technology, energy efficiency and environmental externalities in the iron and steel industry - ait,...

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I r o n & S t e e l I n d u s t r y

TECHNOLOGY, ENERGY EFFICIENCY AND

ENVIRONMENTAL EXTERNALITIES IN THE IRON

AND STEEL INDUSTRY

School of Environment, Resources and Development Asian Institute of Technology

Bangkok - Thailand

Technology, energy efficiency and environmental externalities in the iron and steel industry

Iron Ore Limestone MetallurgicalCoal Scrap

Sinter Plant Blast Furnace(B.F.) Coke Ovens

Sinter Coke

Basic Oxygen Furnace (BOF)/Open Hearth Furnace (OHF)

Ingot Casting

ContinuousCasting

LiquidSteel

Primary Rolling

Hot Rolling Mill

Cold RollingMill

Sheets, Plates,Sections, Strips,

Pipes

Hot Coils,Sections, Plates,

Bars, Pipes, Rods

Water Spray(for cokeproducts)

By-products (totreatment plant)

B.F. Slag

Granulationto

cementplant

SlagProcessing

Roadbuildingmaterial

SteelScrap

to steelplant

Steel Slag(1500°C)

PigIron

Oxygen

SteamSteam

Water Jet

RAW MATERIAL

IRON MAKING

STEEL MAKING

CASTING & PRIMARYROLLING

ROLLING &FINISHING

FINAL PRODUCT

Iron & Steel Industry

Brahmanand Mohanty

School of Environment, Resources and Development Asian Institute of Technology

Bangkok - Thailand

Technology, Energy Efficiency and Environmental Externalities in the Iron and Steel Industry © Asian Institute of Technology, 1997 Edited by Brahmanand Mohanty Published by School of Environment, Resources and Development Asian Institute of Technology P.O. Box 4, Pathumthani 12120 Thailand e-mail: [email protected] NOTICE Neither the Swedish International Development Cooperation Agency (Sida) nor the Asian Institute of Technology (AIT) makes any warranty, expressed or implied, or assume any legal liability for the accuracy, completeness, or usefulness of any information, appratus, product, or represents that its use would not infringe privately owned rights. Reference herein to any trademark, or manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by Sida or AIT. ISBN 974 - 8256 - 71 - 5 Printed in India by All India Press, Pondicherry. FOREWORD

The use of fossil fuels leads to the emission of so-called "Green House Gases (GHG)", a concept which comprises carbon dioxide, nitrous oxides, sulfur oxides, etc. In recent years, a good deal of research has provided enough material to put forward the claim that a big increase in the concentration of carbon dioxide in the atmosphere would lead to a rise in the average global temperature, with negative consequences for the global climate. This claim has been confirmed by the United Nations Intergovernmental Panel on Climate Change (IPCC) in its second scientific assessment published in 1996. Global warming can have catastrophic impact on human and global security: island nations and low lying coastal regions would be permanently drowned by the rise in the level of the oceans brought on by the melting of polar ice; drought would become widespread; and desertification would expand and accelerate. Persistent famines, mass migrations and large-scale conflict would be the result. Agriculture, food and water security, and international trade would come under severe strain. Until recently, industrialized countries have accounted for most of the emission of the GHG, in particular carbon dioxide, because their economic development has been very strongly based on the use of fossil fuels. However, the same dynamic has also led to a situation where the newly industrializing countries of Asia and Latin America (the strong South) are today contributing significantly to the emission of carbon dioxide. This tendency will spread to and encompass an increasing number of developing countries unless both the industrialized and the developing countries jointly agree on implementing the measures to halt and then reverse the global trend towards a rapid rise in the emission of carbon dioxide. That is the central purpose of the IPCC, which has succeeded in obtaining commitments from most of the industrialized countries to reduce their emissions of carbon dioxide. At the 1995 meeting in Berlin of the Conference of the Parties (CoP) to the United Nations Climate Convention, it was decided to initiate negotiations to strengthen the emission-reduction measures by the industrialized countries, as well as countries of Eastern Europe and the Former Soviet Union. The final negotiations are planned to take place at the December 1997 meeting in Kyoto of the CoP, which ought to result in legal instruments to ensure that the agreed measures are being fulfilled. The fossil fuel generated climate problem is very complex, with strong vested interests and special alliances. There is still considerable skepticism in the developing world about the need for measures to counter global warming, in particular in the strong South, which in no way wants to jeopardize its own rapid economic development. It is therefore imperative to find innovative solutions, both technical and institutional, to the climate problem, which are acceptable to both the North and the South. Meeting this challenge calls for inter alia research programs that tackle the technological, techno-economic and policy problems in promoting the transition to decreasing use of fossil fuels, increasing energy efficiency and fuel substitution, and carbon recycling systems of energy production and use.

The Asian Regional Research Programme on Energy, Environment and Climate (ARRPEEC) is part of this global effort, which Sida is very pleased to have initiated and is fully supporting. The ARRPEEC comprises technological, techno-economic and policy research on energy efficiency, fuel substitution and carbon recycling in the principal economic sectors of East, Southeast and South Asian countries. M R Bhagavan Senior Research Adviser, Department for Research Cooperation Swedish International Development Cooperation Agency, Sida

PREFACE Industries have always played a crucial role in the socio-economic development of a country. They have contributed primarily to increased prosperity, greater employment and livelihood opportunities. On the other hand, industries are accused of accelerating the consumption of scarce fossil fuels and of polluting the local, regional, and global environment by releasing solid, liquid and gaseous pollutants to their surroundings. Experiences gained worldwide have shown that these impacts of industries on resource use and the environment can be contained through more efficient production processes and adoption of cleaner technologies and procedures. Thus, fossil fuel consumption can be cut down drastically and waste generation can be avoided or minimized to the lowest possible level. Regulatory regimes introduced in several countries have led the industries to adopt appropriate measures. Some countries have adopted economic instruments to reflect the true cost of goods and services by internalizing the environmental costs of their input, production, use, recycling and disposal. The improvement of production system through the use of technologies and processes that utilize resources more efficiently and achieve “more with less” is an important pathway towards the long-term sustenance of industries. It is in this context that a research project was undertaken by the Asian Institute of Technology (AIT), with the support of the Swedish International Development Cooperation Agency (Sida). The project entitled “Development of Energy Efficient and Environmentally Sound Industrial Technologies in Asia” was launched with the specific objective to enhance the synergy among selected Asian developing countries in their efforts to grasp the mechanism and various aspects related to the adoption and propagation of energy efficient and environmentally sound technologies. Three energy intensive and environmentally polluting industrial sub-sectors (cement, iron & steel, and pulp & paper) and four Asian countries of varying sizes, political systems and stages of development (China, India, Philippines, Sri Lanka) were selected in the framework of this study. To enhance in-country capacity building in the subject matter, collaboration was sought from reputed national institutes who nominated experts to actively participate in the execution of the project. The activities undertaken in the first phase of the project were the following:

- Evaluation of the status of technologies in selected energy intensive and environmentally polluting industries;

- Identification of potential areas for energy conservation and pollution abatement in these industries;

- Analysis of the technological development of energy intensive and polluting industries in relation with the national regulatory measures;

- Identification of major barriers to efficiency improvements and pollution abatement in the industrial sector.

Based on the initial guidelines prepared at AIT under the leadership of Dr. X. Chen, discussions were held with the experts from the national research institutes (NRIs) of the four participating countries. The outcomes of these meetings were used as a basis for the preparation of country reports which were presented at two project workshops held at Manila in May 1995 and at Bangkok in November 1995. On the basis of the reports submitted, cross-country comparison reports were prepared at AIT and additional relevant information was sought from the NRIs to bridge some of the gaps found in their respective reports. This is the second of the four volumes of documents which have resulted from this interactive research work between AIT and the NRIs. This volume on “Technology, energy efficiency and environmental externalities in the iron and steel industry” covers a description of the cement manufacturing process, and the energy and environmental aspects associated with it. Then there is a cross-country comparison of the iron and steel sector in the four countries, followed by individual country reports prepared by the four NRIs. The first five chapters were prepared by Dr. B. Mohanty and Dr. Uwe Stoll with the assistance of research associates figuring in the Project Team. Sincere thanks are extended to all the members of the Project Team including the supporting staff, past and present, for their active participation and contribution to the project. The enthusiasm and dynamism of Dr. X. Chen during the execution of the first phase and the understanding and leadership provided by Dr. C. Visvanathan in the crucial completion period of the project are acknowledged here. The project would have never seen the light of the day without the support of Sida. Finally, appreciations are due to two individuals who have actually conceived the Asian Regional Research Programme on Energy, Environment and Climate (ARRPEEC) and provided constant support and encouragement to this specific project under the overall program: Dr. M.R. Bhagawan, Senior Research Adviser at Sida, and Dr. S.C. Bhattacharya, Professor at AIT. Brahmanand Mohanty Asian Institute of Technology June, 1997

PROJECT TEAM

Faculty Members (Asian Institute of Technology - School of Environment, Resources and Development)

- Dr. Xavier Chen, Energy Program (Until February 1996) - Dr. Brahmanand Mohanty, Energy Program - Dr. Uwe Stoll, Environmental Engineering Program (Until January 1996) - Dr. C. Visvanathan, Environmental Engineering Program (From January 1996)

Research Associates (Asian Institute of Technology - School of Environment, Resources and Development)

- Ms. Nahid Amin - Ms. Lilita B. Bacareza - Mr. Z. Khandkar - Mr. Aung Naing Oo - Mr. K. Parameshwaran

National Research Institutes

- Institute for Techno-Economics and Energy System Analysis, Tsinghua University, Beijing, China (Prof. Qiu Daxiong)

- Energy Management Centre, Ministry of Power, New Delhi, India (Mr. S. Ramaswamy)

- Department of Energy, Manila, Philippines (Mr. C.T. Tupas) - Energy Conservation Fund, Ministry of Irrigation, Power and Energy, Colombo,

Sri Lanka (Mr. U. Daranagama) Research Fellows

- Dr. Wu Xiaobo, School of Management, Zhejiang University, China (January-June 1996)

- Ms. Wang Yanjia, Tsinghua University, China (May-November 1996) - Mr. Anil Kumar Aneja, Thapar Corporate R&D Centre, India (May-November

1996) - Ms. Marisol Portal, National Power Corporation, Philippines (May-November

1996) - Mr. Gamini Senanayake, Industrial Services Bureau of North Western Province,

Sri Lanka (May-November 1996)

Table of Contents

1. GENERAL.....................................................................................Error! Bookmark not defined.

2. PROCESS DESCRIPTION .........................................................Error! Bookmark not defined. 2.1 INTRODUCTION ....................................................................Error! Bookmark not defined. 2.2 THE CONVENTIONAL ROUTE ...............................................Error! Bookmark not defined.

2.2.1 Mining and Iron Ore Concentration ............................Error! Bookmark not defined. 2.2.2 Iron Making..................................................................Error! Bookmark not defined.

2.2.2.1 Blast furnace option...................................................Error! Bookmark not defined. 2.2.2.2 Direct reduction iron..................................................Error! Bookmark not defined. 2.2.2.3 Smelting reduction (SR) process ...............................Error! Bookmark not defined.

2.2.3 Steel Making.................................................................Error! Bookmark not defined. 2.2.3.1 Open hearth furnace ..................................................Error! Bookmark not defined. 2.2.3.2 Basic oxygen furnace ................................................Error! Bookmark not defined. 2.2.3.3 Electric arc furnace....................................................Error! Bookmark not defined. 2.2.3.4 Bessemer converter ...................................................Error! Bookmark not defined.

2.2.4 Rolling Mill Operations ...............................................Error! Bookmark not defined. 2.2.5 Pickling ........................................................................Error! Bookmark not defined. 2.2.6 Finishing ......................................................................Error! Bookmark not defined.

3. ENERGY ISSUES IN IRON AND STEEL INDUSTRY...........Error! Bookmark not defined. 3.1 TYPICAL ENERGY CONSUMPTION PATTERNS ......................Error! Bookmark not defined. 3.2 ENERGY EFFICIENCY MEASURES.........................................Error! Bookmark not defined.

3.2.1 Short Term Measures ...................................................Error! Bookmark not defined. 3.2.2 Medium Term Measures...............................................Error! Bookmark not defined.

3.2.2.1 Changes And modifications in processes ..................Error! Bookmark not defined. 3.2.2.2 Waste heat recovery ..................................................Error! Bookmark not defined. 3.2.2.3 Self power generation...............................................Error! Bookmark not defined.

3.2.3 Long Term Measures....................................................Error! Bookmark not defined. 3.2.4 Energy Management Program.....................................Error! Bookmark not defined.

3.3 NEW ENERGY EFFICIENT TECHNOLOGIES FOR STEEL MAKINGError! Bookmark not defined. 3.4. CONCLUDING REMARKS .....................................................Error! Bookmark not defined.

4. SOURCES OF POLLUTANTS AND POLLUTION CONTROLError! Bookmark not defined. 4.1 SOURCES AND CHARACTERISTICS OF POLLUTANTS ............Error! Bookmark not defined.

4.1.1 Wastewater...................................................................Error! Bookmark not defined. 4.1.1.1. Iron ore concentration...............................................Error! Bookmark not defined. 4.1.1.2. Coke process.............................................................Error! Bookmark not defined. 4.1.1.3. The blast furnace ......................................................Error! Bookmark not defined. 4.1.1.4. Pickling process........................................................Error! Bookmark not defined.

4.1.2. Gaseous and particulate emissions .............................Error! Bookmark not defined. 4.1.2.1. Preparation of iron ore..............................................Error! Bookmark not defined. 4.1.2.2. Coking ......................................................................Error! Bookmark not defined. 4.1.2.3. Blast furnace operation.............................................Error! Bookmark not defined. 4.1.2.4. Steel making .............................................................Error! Bookmark not defined.

4.1.3 Solid waste generated ..................................................Error! Bookmark not defined. 4.2. CURRENT POLLUTION ABATEMENT STRATEGIES AND TECHNOLOGIESError! Bookmark not defined.

4.2.1. Air pollution control....................................................Error! Bookmark not defined. 4.2.2. Water pollution control ...............................................Error! Bookmark not defined.

5. CROSS COUNTRY COMPARISON OF THE IRON AND STEEL INDUSTRYError! Bookmark not define5.1 INTRODUCTION ....................................................................Error! Bookmark not defined. 5.2 OVERVIEW OF THE INDUSTRY..............................................Error! Bookmark not defined.

5.2.1 Role in National Economy ...........................................Error! Bookmark not defined. 5.2.2 Share in Total Energy Consumption ...........................Error! Bookmark not defined.

5.2.3 Trends of Production....................................................Error! Bookmark not defined. 5.2.4 Mills and Capacities ....................................................Error! Bookmark not defined.

5.3 PARAMETERS AFFECTING ENERGY EFFICIENCY..................Error! Bookmark not defined. 5.3.1 Steel-making Process Mix ............................................Error! Bookmark not defined. 5.3.2 Iron to Steel Ratio ........................................................Error! Bookmark not defined. 5.3.3 Share of Continuous Casting .......................................Error! Bookmark not defined. 5.3.4 Energy Consumption at Sub-Processes........................Error! Bookmark not defined. 5.3.5 Capacity of Equipment.................................................Error! Bookmark not defined. 5.3.6 Awareness on Energy Conservation ............................Error! Bookmark not defined.

5.4 PARAMETERS AFFECTING POLLUTION ABATEMENT MEASURESError! Bookmark not defined. 5.4.1 Causes for the Pollution Problems ..............................Error! Bookmark not defined. 5.4.2 Current Water Pollution Control Strategies ................Error! Bookmark not defined. 5.4.3 Current Air Pollution Control Strategies.....................Error! Bookmark not defined. 5.4.4 Current Solid Waste Control Strategies.......................Error! Bookmark not defined. 5.4.5 Comparison of Effluent and Emission Characteristics Error! Bookmark not defined.

5.5 POTENTIAL FOR ENERGY EFFICIENCY IMPROVEMENTS.......Error! Bookmark not defined. 5.5.1 Measures on Structure of the Industry .........................Error! Bookmark not defined. 5.5.2 Measures on Raw Materials and Products ..................Error! Bookmark not defined. 5.5.3 Potential of Energy Conservation Measures ...............Error! Bookmark not defined.

5.6 POTENTIAL FOR POLLUTION ABATEMENT...........................Error! Bookmark not defined. 5.7 CONCLUSION........................................................................Error! Bookmark not defined.

6. PROFILE OF IRON AND STEEL INDUSTRY IN ASIAN INDUSTRIALIZING COUNTRIES............................................................ ERROR! BOOKMARK NOT DEFINED. 6.1 COUNTRY REPORT: CHINA...........................................ERROR! BOOKMARK NOT DEFINED.

6.1.1 Introduction..................................................................Error! Bookmark not defined. 6.1.2 Technological Trajectory of China’s Iron & Steel IndustryError! Bookmark not defined.

6.1.2.1 Capacity and Productivity of the Iron & Steel Industry of ChinaError! Bookmark not defined. 6.1.2.2 Product Mix, Process Mix and Equipment Used.......Error! Bookmark not defined. 6.1.2.3 Role of the Iron & Steel Industry in the Economic Development of ChinaError! Bookmark not define

6.1.3 Evolution of Energy Efficiency in the Iron & Steel Industry of ChinaError! Bookmark not defined. 6.1.3.1 Breakdown of Energy Consumption .........................Error! Bookmark not defined. 6.1.3.2 Energy Efficiency and Specific Energy ConsumptionError! Bookmark not defined. 6.1.3.3 Energy Conservation Potential Analysis ...................Error! Bookmark not defined.

6.1.4 Environmental Externalities of the Iron & Steel Industry of ChinaError! Bookmark not defined. 6.1.5 Potential for Energy Efficiency Improvement and Pollution Abatement through

Technological Change ................................................Error! Bookmark not defined. 6.1.5.1 Energy Efficiency Improvement in the Iron and Steel IndustryError! Bookmark not defined. 6.1.5.2 Main Measures Used to Control Pollution in the Metallurgy SectorError! Bookmark not defined.

6.1.6 Status of Application of New Technologies..................Error! Bookmark not defined. 6.2 COUNTRY REPORT: INDIA....................................................Error! Bookmark not defined.

6.2.1 Introduction..................................................................Error! Bookmark not defined. 6.2.2 Technological Trajectory of India’s Iron & Steel IndustryError! Bookmark not defined.

6.2.2.1 Structure of the Indian Steel Industry: Capacity and ProductionError! Bookmark not defined. 6.2.2.2 Product Mix and Capacity Utilization .......................Error! Bookmark not defined. 6.2.2.3 Trends in the Steel Making Process ..........................Error! Bookmark not defined.

6.2.3 Evolution of Energy Efficiency in the Iron & Steel Industry of IndiaError! Bookmark not defined. 6.2.3.1 Energy and Material Consumption............................Error! Bookmark not defined. 6.2.3.2 Energy Consumption at the Process Centers .............Error! Bookmark not defined. 6.2.3.3 Specific Energy Consumption ...................................Error! Bookmark not defined. 6.2.3.4 Energy Saving Measures Implemented in Recent YearsError! Bookmark not defined.

6.2.4 Environmental Externalities of the Iron & Steel Industry of IndiaError! Bookmark not defined. 6.2.4.1 Pollution-Areas in the Iron and Steel Industry of IndiaError! Bookmark not defined. 6.2.4.2 India’s Environmental Standards for Pollution Control and AbatementError! Bookmark not defined.6.2.4.3 Pollution Control Equipment Installed in the Iron & Steel Industry of IndiaError! Bookmark not defi

6.2.5 Potential for Energy Efficiency Improvement and Pollution Abatement through Technological Changes ..............................................Error! Bookmark not defined. 6.2.5.1 Energy Efficiency Improvement through Energy ConservationError! Bookmark not defined. 6.2.5.2 Potential for Pollution Abatement through Management and TechnologyError! Bookmark not define

6.2.6 Status of Application of New Technologies..................Error! Bookmark not defined. 6.3 COUNTRY REPORT: PHILIPPINES..........................................Error! Bookmark not defined.

6.3.1 Introduction..................................................................Error! Bookmark not defined. 6.3.2 Technological Trajectory of the Philippine Steel IndustryError! Bookmark not defined.

6.3.2.1 Capacity.....................................................................Error! Bookmark not defined. 6.3.2.2 Product Mixes...........................................................Error! Bookmark not defined. 6.3.2.3 Current Position in the National Economy................Error! Bookmark not defined.

6.3.3 Evolution of Energy Efficiency with Technological ChangeError! Bookmark not defined. 6.3.4 Environmental Externalities of Technological Development in the Philippine Iron

and Steel Industry .......................................................Error! Bookmark not defined. 6.3.5 Potential for Energy Efficiency Improvement and Pollution Abatement through

Technological Change ................................................Error! Bookmark not defined. 6.3.5.1 Energy Efficiency......................................................Error! Bookmark not defined. 6.3.5.2 Pollution Abatement ..................................................Error! Bookmark not defined. 6.3.5.3 Managerial Improvement ..........................................Error! Bookmark not defined.

6.3.6 Status of Application of New Technologies for Energy Efficiency Improvement and Pollution Abatement ...................................................Error! Bookmark not defined.

6.3.7 Conclusions and Further Studies .................................Error! Bookmark not defined. 6.4 COUNTRY REPORT: SRI LANKA ..........................................Error! Bookmark not defined.

6.4.1 Introduction..................................................................Error! Bookmark not defined. 6.4.2 Technological Trajectory of the Sri Lankan Iron and Steel IndustryError! Bookmark not defined.

6.4.2.1 Capacity and Production............................................Error! Bookmark not defined. 6.4.2.2 Product Mix, Process Mix and Capacity Utilisation..Error! Bookmark not defined. 6.4.2.3 Role of the Industry in National Economy................Error! Bookmark not defined.

6.4.3 Evolution of Energy Efficiency in the Iron and Steel Industry of Sri LankaError! Bookmark not defin6.4.4 Environmental Externalities in the Iron and Steel Industry of Sri LankaError! Bookmark not defined6.4.5 Potential for Energy Efficiency Improvement and Pollution Abatement through

Technological Change ................................................Error! Bookmark not defined.

General 1

GENERAL

The iron and steel industry is one of the largest industrial energy consumers, accounting for 20-45% of total industrial energy demand in many countries. It plays a significant role in the economic growth of developing countries. Recent years have seen rapid industrialization and infrastructure development leading to higher steel consumption and consequently increased production requirement in Asian industrializing nations. Although production has increased mainly due to extended plant capacities and introduction of new factories, little attention had been paid to efficient energy utilization and environmental pollution control. The main causes for energy inefficiency and environmental pollution are outdated production technology in use, aged industrial infrastructures, lack of management skills and coal dominated energy structures. Among the industries which give rise to excessive concentrations of dangerous chemical substances, obnoxious exhaust gases and contaminated process waters, the iron and steel industry is one of the largest and severest players. Therefore, there is a need for an integrated approach towards energy and environment management of the industry so that better energy efficiency and environmental friendliness can be achieved. This document describes the process technology in use, energy saving opportunities, major causes and sources of pollution and the techniques and practices for pollution abatement related to the iron and steel industry. The paper also presents the technological trajectory of the iron and steel industry in four Asian industrializing countries, namely P.R. China, India, the Philippines and Sri Lanka, preceded by a cross-country comparison of the industry.

Technology, Energy Efficiency and Environmental Externalities in the Iron and Steel Industry 2

2. PROCESS DESCRIPTION

2.1 Introduction

The iron and steel industry is very complex and usually vertically integrated, requiring high temperatures at various stages of the production process. New steel plants are integrated complexes containing a variety of units such as materials loading and handling facilities, coal washeries, coke ovens, several types of furnaces (open hearth, electric, basic oxygen, etc.), converters, steel making shops, blooming or slab and billet making shops, rolling and finishing mills and ancillary units like oxygen plants, power plants, gas plants, slag disposal units, foundries, heat treatment units, cooling towers, water treatment plants and so on. Iron is cast at temperatures over 1200°C; steel at about 1600°C. During many of the additional processes like coke making, sintering, pelletizing and hot rolling, temperatures of 1000°C are common while 1200°C and higher are not exceptional. Based on the raw materials used and processes involved, steel mills can be classified into two groups:

- Integrated mills, which require the metallurgical coal, and involve four major process stages: - reduction of coal to coke - iron making process - conversion of iron to steel, and - refining, casting and finishing processes

- Mini mills (secondary mills), which do not use metallurgical coal, and involve the

following processes: - iron making process (for direct reduction mills only) - conversion of iron to steel, and - refining, casting and finishing processes

The iron making process and its conversion to steel can be of various combinations such as:

- blast furnace and open hearth furnace (BF-OHF), - blast furnace and basic oxygen furnace (BF-BOF), - direct reduction and electric arc furnace (DR-EAF), and - scrap based electric arc furnace (Scrap-EAF).

Of these combinations, the first two options are used in integrated mills while the last two options are used in mini mills. Presently, modern direct reduction furnaces are emerging as a promising technology for use in integrated steel plants as well. Simplified flow diagrams depicting typical steel mills are shown in Figures 2.1. and 2.2, while Table 2.1 shows the characteristics of principal methods of producing steel.

Process Description 3


Sinter Plant Blast Furnace(B.F.) Coke Ovens

Sinter Coke


Ingot Casting

ContinuousCasting

LiquidSteel

Primary Rolling

Hot Rolling Mill

Cold RollingMill


Pipes


Bars, Pipes, Rods

Water Spray(for cokeproducts)

By-products (totreatment plant)

B.F. Slag

Granulationto

cementplant

SlagProcessing

Roadbuildingmaterial

SteelScrap

to steelplant

Steel Slag(1500°C)

PigIron

Oxygen

SteamSteam

Water Jet

RAW MATERIAL

IRON MAKING

STEEL MAKING

CASTING &PRIMARYROLLING

ROLLING &FINSHING

FINAL PRODUCT

Figure 2.1. Simplified flow diagram of conventional integrated iron and steel mills


RAW MATERIAL Iron Ore Natural GasScrap

DirectReductionFurnace

Gas ReformerReducing

Gas

Electric ArcFurnace

Preheated Ladle

Tundish

ContinuousCasting

SpongeIron

Liquid Steel

Billets

Storage(for processingat a later time)

Reheat Furnace

Hot Rolling Mill

Bars, Rods,Sections, etc.

IRON MAKING

STEEL MAKING

CASTING

ROLLING

FINAL PRODUCT

Scrap Preheating

Figure 2.2. Simplified flow diagram of conventional mini steel mills


Table 2.1. Characteristics of principal methods of producing steel

Integrated Steel Plant Mini Steel Plant Type of Furnace BF-OHF BF-BOF DR-EAF Scrap-EAFIron making stage Blast furnace

(BF) Blast furnace

(BF) Direct

reduction furnace (DR)

-

Steel making stage Open hearth furnace (OHF)

Basic oxygen furnace (BOF)

Electric arc furnace (EAF)

Electric arc furnace (EAF)

Capacity range a/ (million tons/yr)

0.5-2.0 0.5-3.7 0.2-1.0 0.2-0.8

Investment cost b/ (US$ per ton

installed in 1982 prices)

1,700-2,000 c/

1,500-1,800 500-900 d/ 350-550

Main material inputs Iron ore, scrap

Iron ore, scrap Iron ore, scrap scrap

Main energy inputs Coking coal, oil, electricity

Coking coal, oil, electricity

Natural gas, e/ electricity

Electricity

Note: a/ Typical range (crude steel). b/ Includes working capital and interest during construction. c/ Rough estimate because new capacity addition by this route has been abandoned. d/ Does not include pellet plant. e/ Coal-based DR processes are currently being developed. (Source: Nippon Steel Corporation, hereafter referred to as NSC) The following section 2.2 elaborates the conventional options while the new and alternative technologies are discussed in subsequent sections. 2.2 Conventional Route

There are four major stages of conventional steel processing route: - mining and iron ore concentration (beneficiation), - iron making (usually blast furnace treatment), - steel production (usually basic oxygen furnace treatment), and - rolling and finishing

Iron ore concentration is generally done at or near the mining site, whereas the last three processes are carried out at steel plants located elsewhere.


2.2.1 Mining and iron ore concentration

Procurement and preparation of iron ore and other essential raw materials for feeding the steel plant involves mining, transportation to site, stock piling and then crushing, grinding, screening and grading operations for obtaining the required sizes. This is followed by concentration of ores (to achieve an ore-rich product), blending (to ensure a feed of uniform chemical composition), agglomeration of fine concentrates, etc. The iron is found in nature as oxides - hematite (Fe2O3) and magnetite (Fe3O4) - and as carbonates and silicates. Typical impurities in the iron ore are sulfur, aluminum oxide (Al2O3), phosphorus, silica (SiO2) and titanium. Today, hematite is scarce and the primary available ore is taconite, which is a lower grade ore, usually consisting about 25% iron, which is present as either (Fe2O3) or (Fe3O4). So the taconite must be concentrated; usually this is done at the mining site. The taconite is crushed so that most of the silicates (sand) are no longer attached to the iron oxide particles. The pulverized solids are mixed with water to form a slurry; this slurry of the fine particles is then passed near a magnet which separates out the magnetic iron particles, while pure sand and some nonmagnetic taconite remain in the slurry. The ore particles are thus concentrated to about two-thirds iron by weight. The iron-containing particles are agglomerated by some low-pressure pelletizing technique into about 25 mm moist balls, sintered in a furnace, and then taken to the steel makers. The sintering operation consists of placing the moist pellets on a conveyer belt and then blowing very hot air through them. As the pellets reach high temperature, they dehydrate and coalesce into fairly hard balls. From the grate, the pellets are taken to a kiln, where they are strongly heated and hardened. 2.2.2 Iron making

Extraction of iron from the ore may be done in either of the two different ways practiced at present:

- Blast Furnace Treatment, and - Direct Reduction

The output from the blast furnace is known as pig iron and that from direct reduction furnace is called sponge iron. Blast furnace treatment is the most commonly used method of iron making and will be discussed to some detail in this section. 2.2.2.1 Blast furnace option

In the blast furnace, the concentrated ore is treated with coke and limestone. Typical proportion of raw material feeding is either iron ore: coke: limestone: air = 7 : 3:1 : 16 or iron ore : scale and scrap : coke : limestone : air = 15 : 2:6 : 2 : 25 by weight. The coke converts Fe2O3 and Fe3O4 into pure iron (Fe) by removing impurities. Ore and limestone are directly fed to the blast furnace while the coal charge is led to the coke ovens for carbonization. The different process stages involved with the blast furnace treatment are:


Coke Oven

To produce coke, coal is heated in a tall, narrow coking oven in a low-oxygen atmosphere. The processes in use for making metallurgical coke are the beehive process and the byproduct process. Of these two, the byproduct process, shown in Figure 2.3 is most widely used. After coal is blended and weighed, a hopper-equipped vehicle operating on top of the oven is loaded with a charge of coal. This vehicle, called a Larry car, moves to the oven to be charged, and the coal is loaded through charging holes at the top of the oven. Following the heating or coking process, the doors on each end of the oven are removed, and the coke is pushed with a ram from the oven into a coke car. The car is then transferred to a quench tower where water, often wastewater from another step in the process, is sprayed on the hot coke to cool it for transport, use, or further preparation. The gases driven out off the coal, are recovered as coal tar, ammonium sulfate, light oil, and coke-oven gas, which eventually get converted into substances such as explosives, fertilizers, and synthetic rubber or are used for fuel. The following products are obtained from the burning of a ton of coal: 600 - 700 kg of coke, 8 - 12 kg of (NH4)2SO4, 22 - 54 liters of tar, 1000 - 1050 m3 of gas, 45 - 900 g phenol, 9 - 15 liters of light oil and 230 - 550 g naphthalene (Nemerow, 1978). In blast furnace, the coke burns with air at about 1500°C. In limited O2, the coke can react:

Coke + 1/2O2 CO

The CO is a reducing agent that can react with Fe2O3 and Fe3O4 to produce Fe. In addition, the heat melts the iron and the impurities. The latter floats and is skimmed off as the white hot liquid iron flows out of the furnace. Further, in the case of coke ovens, choking of collecting mains leads to spill-over of ammonia liquor inside the ovens through the ascension pipes if the liquor does not find an outlet. Such spilling damages the flues and almost stops the operation of the batteries. This trouble occurs due to gradual accumulation of spill-over liquor, when the tar and liquor also become viscous causing further difficulties in detecting and checking the occurrence. This is a major danger (although rare) to personal safety and environment which should be prevented at all costs. Fluctuations on steam supply to the exhaust may also affect the suction maintained in the gas main and the pressure in the collecting main. This trouble is not uncommon in steel plants having many bulk consumers of high pressure steam and requires proper tackling to prevent leakage and bursts of foul gases. Limestone

The limestone (primarily CaCO3) can act as a flux, causing the impurities - particularly silicon dioxide (SiO2) - to melt at lower temperatures than they otherwise would. When CaCO3 is heated strongly, it decomposes into calcium oxide:

CaCO3 CaO + CO2


This process is called calcination. The CO2 thus generated can react as:

CO2 + C 2CO The CO acts as a reducing agent. The CaO reacts with SiO2 to form CaSiO2 which is the principal component of the waste slag. The slag can be separated from the molten iron because it is lighter and floats on the iron surface. Blast furnace treatment

In blast furnace, the coke is fed through the top, along with iron ore and limestone, and the mixture is blasted from below by hot air. The coke located near the bottom has adequate oxygen to react completely to form CO2. As the CO2 produced rises in the furnace, it encounters more coke and greatly reduced oxygen supply. The CO2 then reacts further with coke to form CO:

CO2 + C 2CO The CO can react with the iron ore, purifying it as follows:

Fe2O3 + 3CO 2Fe + 3CO2 The Fe thus produced is called crude or pig iron. Figure 2.4 illustrates a typical blast furnace. Basically, a blast furnace is a large vertical cylinder, lined with heat resistant fire brick, and encircled by plates for the flow of cooling water. Common dimensions would be 50 m tall and 10 m in diameter at the base. The hot air is blasted into the lower part of the furnace at a rate of more than 2,800 m3/minute. Each blast furnace is equipped with several stoves that provide this hot air. The stoves are heated to high temperatures, air is blown through them, heated to 1500°C - 1650°C, and then blown into the blast furnace. The stoves are alternated, i.e., while one is being emptied of air, the others are heating. This air supplies both the oxygen and heat necessary to initiate and sustain the combustion in the furnace. The hot air is blasted into the furnace through holes (called tuyeres) located near the bottom. The hot air ignites the coke, causing the raw materials to melt and flow together, so the above described reactions take place inside the furnace. As the materials coalesce, the volume decreases, allowing for more raw materials to be fed in at the top. The pure melted iron, being denser than the impurities, settles at the bottom of the furnace, and the slag floats on top of this. Every four or five hours it is necessary to tap the furnace to draw off the molten iron. This is done by unplugging the iron notch located near the floor. The iron flows in a cement trough to the ladle cars, which can each hold up to 160 tons of molten iron. After tapping, and the typical removal of about 400 tons of molten metal, the furnace is replugged. It is also necessary to frequently draw off the waste slag. This procedure is similar


to that for the molten iron, the plugs being located higher on the furnace, above the iron layer. Because of the heating value of blast furnace gas, it is used as a fuel and must be cleaned before doing so as large quantities of dust are entrained with it. Basic cleaning devices include cyclones, wet scrubbers, electrostatic precipitators, and baghouse filters. 2.2.2.2 Direct reduction of iron

Direct reduction processes, producing sponge iron, are suitable for small scale operations, and are therefore generally used in mini-mills with electric arc furnaces. They avoid the coking plant and involve the reduction of dry, pure iron oxides in the presence of a reducing agent at temperatures around 900 to 1000°C. The process yields dark-gray, porous masses of the same size and shape as the original lumps or ore-particles. At 1000°C, the ore particles begin to sinter and at 1200°C, a pasty porous mass forms. If carbon is present in the reducing agent, then at 1300°C, the mass begins to fuse rapidly absorbing the carbon. There are four basic categories of commercial scale direct reduction processes as summarized in Table 2.1.

2.2.2.3 Smelting reduction (SR) process

This is a prospective technology for the production of molten iron (>1500°C) using reduced or pre-reduced iron ore. The molten iron is subsequently treated in an oxygen converter. The process is suitable for small scale production of iron and steel based on coal. The different types of smelting reduction technologies are listed below:

i. Inred process: consists of flash smelting chamber and electric arc furnace. Pre-reduction and smelting reduction devices are integrated in a single unit. ii. Elred process: consists of pre-reduction unit (pressurized circulating fluidized bed) and a DC electric arc furnace as the smelting reduction furnace equipped with a hollow single-electrode for charging the materials. iii. Plasmasmelt process: iron ore (pre-reduced in a fluidized bed reduction furnace) and coal are blown into the main reactor, a shaft furnace, through tuyeres together with top gas reduced into plasma. iv. Krupp process: the molten iron contains about one percent carbon and is refined in the bottom-blown oxygen converter.

v. KR process: consists of a shaft furnace for reduction and a melting furnace.


Table 2.1. Commercially available basic direct reduction processes

Process Reducing agent/Fu

el

Raw material used

Characteristics

Shaft furnace process

Gaseous (30-40%)

Lump ores, pellets

Operating temperature: 800-900°C

Static bed process Gaseous Lump ores, pellets

Fluidized bed process

Gaseous Relatively fine ores (60 µ - 6 mm)

Higher reducing gas temperature enhances productivity, but at temperatures beyond 800°C, metallic particles tend to stick together.

Rotary kiln process Solid Extensive range (coarser fines to lump ores)

Various types of solid reducing agents and considerably high temperature reduction.

2.2.3 Steel making

The conventional route for integrated steel plants is the blast furnace option in which the pig iron from the blast furnace is further treated in a steel making furnace to produce steel. Pig iron is a combination of about 95% iron, 3-4% carbon and small amounts of manganese, phosphorus, sulfur and silicon. It is not a good structural material owing to its inferior strength caused primarily by the presence of carbon impurities. The purpose of the steel making stage is to remove impurities, primarily the excess carbon, and to add desirable materials to form alloys of iron. The steps are aimed at enhancing the strength and durability of the product. The specific properties of various types of steel can also be influenced by the type of heat treatment steps to which it is subjected. There are several types of steel such as carbon steel, alloy steel, tool steel, etc. Steel is processed not only with pig iron as the sole raw material, but also with scrap iron and scrap steel added to it. The steel production process itself is very complex. The metal must undergo several treatment steps which are quite diverse, as are the environmental considerations. Rolling mill operations, pickling, final shaping and finishing follow these steps. There are four common methods of steel-making:

- Open Hearth Furnaces, - Basic Oxygen Process, - Electric Furnaces, and


- Bessemer Converter. 2.2.3.1 Open hearth furnace

Use of an open hearth furnace is a classical steel production method. A schematic diagram of a open hearth furnace is shown in Figure 2.5. Here, mixture of scrap iron, steel and pig iron are melted to produce steel. The furnace consists of an open, saucer-shaped floor, which is exposed directly to flames. The entire furnace is lined with refractory brick. Air and fuel (gas, oil, tar, etc.) are heated below the hearth and then blown in directly above the steel and ignited so the temperatures reach to about 1650oC. After 8-10 hours, the batch of the melted steel is tapped from the side, opposite from where the raw materials are added. Each batch typically weighs 50-500 tons, depending upon the furnace capacity. The typical feed consists of about 5-6% CaCO3, and equal portion of pig and scrap iron. Initially, the furnace is filled with CaCO3 and scrap. The CaCO3 acts as a flux, as in the blast furnace operations, thus removing impurities and forming a slag. The impurities are removed by oxidation caused by the O2 in the air and the Fe2O3 from the rusty scrap. The Fe2O3, for example, can react with the excess C as:

Fe2O3 + 3C 2Fe + 3CO

The limestone will react with the sulfur and phosphorus oxides, and prevent their emission:

CaO + SO2 CaSO3

6CaO + P4O10 2Ca3(PO4)2.

In addition, it will react with the silicon and manganese oxides, the products of which form part of the slag. After about an hour, the molten pig iron is added. By this stage, much of the remaining carbon in the iron has boiled off as gaseous CO2. After the desired amount of carbon is removed from the mixture, manganese-containing Spiegeleisen can be added to help the removal of some of the entrained O2. Spiegeleisen is typically 16-28% manganese, less than 6.5% carbon, and 1-4.5% silicon. After about half an hour, as the furnace is tapped, ferromanganese is added to the steel to further remove more O2. The tapping procedure allows the molten product to overflow the ladle so that the slag runs over into a separate ladle called a slag thimble; the steel is then poured into ingot molds. At this stage, small amounts of aluminum may be added to further oxidize the steel. 2.2.3.2 Basic oxygen furnace

The basic oxygen process (BOP) or Linz-Donawitz (LD) process is the same as the open hearth process, except that it uses O2, not air. This adaptation permits a faster and more economical processing of the materials. The open hearth process typically takes 8 hours to process the steel; the BOP, 40-45 minutes. Due to faster process time, lower energy consumption makes BOP the process of choice, replacing the earlier open hearth furnaces.


In the industrial market economies, 67% of steel is manufactured in BOF whereas only 3% is from OHF.

2.2.3.3 Electric arc furnace The electric arc furnace is a round steel shell, lined with fire brick (Figure 2.6). Three carbon electrodes, each approximately 1800 mm long and 300 mm in diameter, are inserted through top. Large amounts of electricity are fed to the electrodes, the current arcs among the electrodes and the molten slag generating extremely high temperatures of about 1900oC. The melting and refining operations are very similar to those of the open hearth process. The process is, however, restricted primarily to the recovery of scrap steel and alloys, not the processing of pig iron. Much of the product is a precise type of alloy or of carbon steel, so the process is used when it is essential to have a steel with very exacting characteristics. 2.2.3.4 Bessemer converter

The Bessemer converter is an egg-shaped, open-topped, tippable furnace. The converter is tipped on its side, filled with molten iron, and then righted. Air is then blown into the bottom, through the molten steel, at a pressure greater than 20 psi and at a rate of over 700 m3/minute. This air oxidizes the impurities, and burns them out of the iron. As the air flow is initiated, flames and sparks fly upwards of 10 m, changing from red to yellow to white as the manganese, silicon and then carbon are oxidized. The flame dies after about 10 minutes, at which time the steel is poured from the converter. A modern modification of the Bessemer process is to use O2, not air, in order to eliminate problems that are created by the presence of N2 in the air. This process reduces the processing time for steel to 20-25 minutes. Steel made by this process contains larger than average amounts of sulfur and phosphorus. The result of this is a steel that is stiffer, harder, and more easily machined or threaded than similar BOP steel. 2.2.4 Rolling mill operations

After the furnaces, the rolling mill operations are the next step in the steel-making process. These operations consist of either conversion of steel ingots to forms called blooms, slabs or billets by traditional techniques, or slab production by continuous casting. With the conventional techniques, the partially finished steel is first, before any actual mill operations, cooled in molds after the removal from the furnace, and then subjected to a series of steps, including chipping, grinding, and scarfing. The scarfing uses O2 torches to remove surface defects. The process therefore produces iron oxide fumes as well as slag and scale. Slag and scale are washed off by water jets under pressure. The steel ingots must be heated to about 1200oC before shaping, and this is usually done in heating pits called soaking pits. At this temperature, the ingots become white hot and somewhat soft. The steel then goes to one of several different types of mills, depending upon the ultimate product desired.


The rolling mills resemble large clothes wringers, compressing the softened ingots between heavy rolls into long, thin shapes. Mills have typically two, three or four rolls through which the steel must pass. After an initial hot rolling, much sheet steel may be further processed by a cold rolling procedure. Many plants are now instituting continuous casting. Rather than cooling the steel in molds after the furnace operations and then re-heating it prior to rolling, the molten steel is allowed to cool only slightly (to a temperature comparable to that obtained in the soaking pits) and then rolled immediately into the desired shapes. Thus, the energy consumption for steel-making is reduced significantly. 2.2.5 Pickling

Most steel products need to undergo some further shaping after the initial rolling mill operations. Before this final shaping of the steel can occur, the steel must undergo a pickling process. The purpose of this step is to remove dirt, grease and especially iron oxide scale which accumulates on the metal during fabrication. Usually, either sulfuric acid (H2SO4) or hydrochloric acid (HCl) is used. For many years, H2SO4 was the major acid used, but its rising cost, combined with the decreasing cost of HCl, have made the latter the primary choice for new installations. Hydrochloric acid pickling differs from H2SO4 pickling in the basic chemistry of the pickling action. Hydrochloric acid readily dissolves all the various oxides of iron in the scale, yet reacts relatively slowly with the base material. The dissolved solids in the HCl pickle liquor are far below saturation concentration and the steel is left clean and free of crystals or insoluble slime. Sulfuric acid on the other hand acts at a high reaction rate with the parent metal and blows off oxides in the strip. Because of this, more scale-breaking is required before pickling. The benefits of HCl pickling are: easier regeneration of acid; no over pickling and more flexibility on the line; elimination of the secondary scale breaker; high pickling speeds; and a 20% reduction in wastewater volume. An additional advantage is that HCl can pickle faster and at lower concentrations, and supposedly gives a “cleaner” finish. It may however lead to more corrosion. For many purposes, the pickling can be accomplished in a continuous system using several tanks in series, each succeeding tank containing acid of greater strength. The last tank in line contains fresh acid, the first contains the almost spent liquor. This later tank is the one whose contents are disposed of. Newer systems allow lower acid usage, to minimize the environmental effects. 2.2.6 Finishing

The final steel finishing operations consist of process such as final rolling in finishing mills, tin plating, galvanizing, chrome plating, coating, tempering, and/or polishing. Depending upon the equipment available and the intended product specifications, the techniques for


finishing steel vary widely. In general, the finishing mills include rail and structural mills, wire and nail mills, hot and hold strip mills, pipe mills, etc.

Energy Issues in Iron and Steel Industry 15

3. ENERGY ISSUES IN IRON AND STEEL INDUSTRY

3.1 Typical Energy Consumption Patterns

There are two sources of energy utilized in the iron and steel industry, namely primary and secondary. The primary energy sources are metallurgical or coking coal, fuel oil, electricity and natural gas. The secondary energy sources are coke oven gas (COG) from carbonization of coal, blast furnace gas (BFG) from reduction of iron ore with coke and basic oxygen gas (LDG) from decarburization of molten iron. The shares of purchased primary energy sources for different steel making processes are shown in Table 3.1, while the breakdown of secondary energy consumption in a typical BF-BOF plant is illustrated in Figure 3.1. Table 3.1. Specific energy consumption (SEC) and share of primary energy sources

in steelmaking

Process BF-OHF BF-BOF DR-EAF Scrap-EAF SEC (GJ/t of steel)

28.03 25.1 24.68 10.46

Coking Coal (%) 62 71 - - Natural Gas (%) - - 53 - Fuel Oil (%) 24 13 15 41 Electricity (%) 14 16 32 59

Source: NSC

8%

42%

50%BOF gasCoke oven gasBlast furnacegas

Figure 3.1. Breakdown of secondary energy in a typical BF-BOF steel plant

Typical specific energy consumptions for different steel making processes are shown in Figure 3.2. The energy flow in an integrated BF-BOF steel plant is illustrated in Figure 3.3 which distinguishes between primary and secondary energy sources. The energy consumption of sub-processes are given in Figures 3.4 and 3.5 for integrated steel mill and mini-mill, respectively.

16 Technology, Energy Efficiency and Environmental Externalities in the Iron and Steel Industry

0

5

10

15

20

25

30

BF-BOF BF-OHF DR-EAF Scrap-EAF

Ener

gy C

onsu

mpt

ion

in G

J/to

n St

eel

Ironmaking Steelmaking Rolling Others

71.6%

3.4%

16.6%

8.4%

63.2%

14.7%

14.7%

7.4%

18.9%

57.6%

23.7%

1.8%

56%

40%

4%

Figure 3.2. Typical specific energy consumption for steelmaking processes

(Source: NSC) In fact, the specific energy consumptions vary from mill to mill depending on the following factors:

- fuel rate in the BF, - hot metal ratio in the BOF/OHF steel shop, - degree of stabilization of the production flow, and equipment performance, - extent of rolling of finished steel products.

These and other such factors are presented in Figure 3.6. 3.2 Energy Efficiency Measures

The main objectives of energy conservation measures in iron and steel industry are to expand the use of secondary energy and to reduce the requirement of primary purchased energy. These conservation measures can be classified as short, medium and long term measures according to the type of investment and time frame for investment recovery. Figure 3.7 depicts the energy efficiency measures against a process flow diagram for integrated iron and steel plant while Figure 3.8 gives the same for mini steel mills. 3.2.1 Short term measures

These measures involve the application of available technologies without substantial investments, as follows.


Coal 71.3

Sinter Plant

10

Coke Ovens

81.1

Blast Furnace

58.8

BOF/CC

13.1

Rolling Mills

23.4

Power House

25

23.4

Electricity 14.5

Oil Based Energy

12.8

Purchased Energy (100%)

70 14.59.310

8.2

71.3

92

19.25.8

3.5

LPG 1.0

3.57.13.4

Coke 0.4

0.4

6.7 6.6

7.31.9

14.7 Coke

0.1

1.3

0.817.3 a

29.3

4.4

10.1

41.6

2.6

6.0

1.0

3.1

31.6 b

Pig Iron 11.0

20 d

16.2

Sinter

196.5 c

0.3

0.3

1.5

Ingat or cc Slab 4.7

69

2.6

8.0

1.2

5.5 d

0.4 d

0.6 dFinished

Productsa. Tar & Heat Loss b. Reaction Heat, Heat Loss from Furnace & Slag c. Heat Loss of Ingots & slags by Cooling & Other Losses d. Losses

Energy Consumption Purchased Coal & Coke Electricity Oil Based Energy Steam LPG By-Product Gas Coke Oven Gas BF Gas CO Gas Product Flow

Figure 4. Typical Energy Flow in BF-BOF Integrated Steel Plant


Figure 3.3 Typical energy flow in a BF-BOF integrated steel plant


Figure 3.4. Energy consumption of sub-processes in an integrated steel mill

Figure 3.5. Energy consumption of sub-processes in a mini steel mill


Figure 3.6. Main factors affecting energy consumption in a

conventional integrated steel mill

(i) Management practices, such as - inspection to encourage conservation activity, - training programs for operating energy intensive equipment, - turning off motors and heaters when not in use.

(ii) Low level investment programs, such as

- increased pellet usage in blast furnace ( energy saved = 1.15 * 103 MJ/ton of steel) - using coke with less ash and sulfur content - increased EAF capacity - increased use of induction heating of steel slabs (energy saved = 1.37 * 103 MJ/ton of steel) - insulation improvement of furnaces and steam lines - reduction of excess combustion air by installing and regularly maintaining the oxygen

sensor


RAW MATERIAL Iron Ore Limestone MetallurgicalCoal Scrap

Sinter Plant Blast Furnace Coke OvensSinter Coke


Ingot Casting

ContinuousCasting

LiquidSteel

Primary Rolling

Hot Rolling Mill

Cold RollingMill


Pipes


Bars, Pipes, Rods

IRON MAKING

STEEL MAKING

CASTING &PRIMARY ROLLING

ROLLING &FINISHING

FINAL STEELPRODUCT

Process Flow

PigIron

BF : Blast furnaceBOF: Basic oxygen furnaceOHF: Open hearth furnaceSS : Suspended solidsTDS: Total dissolved solids

Figure 3.7. Energy efficient options for integrated iron and steel mill

Energy Efficient Options




Ingot Casting

ContinuousCasting

LiquidSteel

Primary Rolling

Hot Rolling Mill

Cold RollingMill


Pipes


Bars, Pipes, Rods

Energy Flow

PigIron

GasPurification to own plant

Coke oven gas

GasCleaning to gas delivery

Blast furnace gas

B.F

. gas

enric

hmen

t

enric

hed

gas

Energy(2.4 GJ/tof sinter)

Energy(1.4 GJ/tof iron)

Energy(1.4 GJ/tof iron)

Energy incl. Electricity(1.1 GJ/t steel for BOF 3.9 GJ/t steel for OHF)

Energy incl.Electricity(0.2 GJ/t of

slab)

Energy incl.Electricity

Energy incl.Electricity

2.0

GJ/

t of s

lab

for

tota

l Ing

ot &

Prim

ary

Energy incl.Electricity3.0 GJ/t

of product

Energy &Electricity

Crude gas

Crude gas (1500°C)

Exhaust(1500°C)

A.1. Waste heat recovery from sinter coolerA.2. Waste heat recovery from dry quenching of cokeA.3. Blast furnace hot stove top gas recoveryA.4. Pressure recovery turbine for B.F. top gasA.5. External desulfurizationA.6. COREX TechnologyA.7. Oxy-coal blast furnace process

C.1. Continuous casting to replace ingot casting &primary rolling

D.2. Increase in hot direct rolling ratioD.1. High speed rolling mills


RAW MATERIAL Scrap

Electric ArcFurnace

Preheated Ladle

Tundish

ContinuousCasting

Liquid Steel

Billets


Reheat Furnace

Hot Rolling Mill


STEEL MAKING

CASTING

ROLLING

FINAL PRODUCT

Scrap

Electric ArcFurnace

Preheated Ladle

Tundish

ContinuousCasting

Liquid Steel

Billets


Reheat Furnace

Hot Rolling Mill


Electricity(6 GJ/t steel, or

1.7 kWh/kg)

Process Flow Energy Flow

Energy(fuel oil,0.2 GJ/t)

Energy(diesel,

0.14 GJ/t)

Electricity(0.2 GJ/t slab, or0.0556 kWh/kg)

Energy(fuel oil,

1.23 GJ/t)

Recuperator CombustionAir

Exhaust

Electricity& Energy

(3 GJ/t product)

Exhaust gas

Exhaust gas

Scrap Preheating

Sponge Iron Sponge Iron

Scrap Preheating

Figure 3.8. Energy efficient options for mini steel mill

A.1. Ultra high power furnacetransformer

A.2. Oxy-fuel lancers

A.3. Oxy-fuel burnersA.4. Waste heat recovery for scrap

preheatingA.5. Use of burnt lime

A.6. Water cooled roof and panels forwall lining

B.1. Ladle Furnace

A.7. Eccentric bottom tapping

C.1. Self recuperative and regenerativeburners

C.2. Hot charging

Energy Efficient Options

A.8. Direct Current Electric Arc Furnce(DC-EAF)

A.9. Continuous scrap charging

C.3. Direct rolling


3.2.2 Medium term measures

These measures include the switching to new and more efficient technology and recovery of waste heat without significant investment, as follows. 3.2.2.1 Changes and modifications in processes

(i) Continuous casting This is a single process replacing ingot casting, mold stripping, heating in soaking pits, and primary rolling. Here, molten steel from the steel making furnace is directly processed into billets, blooms or slabs, thus leading to higher productivity (increase in final yields by 5-10%), reduction in production time and labor, and energy savings up to 1.69 * 103 MJ per ton of steel. (ii) External desulfurization Energy saving of 0.9 * 103 MJ per ton of steel can be achieved by removing sulfur from pig iron between BF and steel making furnace. (iii) New and modernized BF The characteristics of new and modern BFs are the use of oxygen-enriched blast operation, higher blast temperature and humidity control, elevated top pressure operation, and injection of auxiliary fuels. With these modifications, coke and energy consumption are reduced and BF productivity is raised (energy saved = 0.14 * 103 MJ/ton of steel). (iv) Continuous scrap charging Several charges of scrap into the EAF during a single melting operation cause energy losses due to the frequent openings of the furnace roof. Adaptation of a continuous charging process will lead to an energy saving of the order of 0.6 * 103 MJ per ton of steel. (v) Oxygen enrichment of combustion air in furnaces This improvement can increase the fuel firing rate and reduce the waste gas volume (energy saved = 2.1 MJ/ton of steel for O2 consumption of 7 m3 ). (vi) Scrap preheating with oxy-fuel burners Electricity consumption in EAF can be replaced with the other fuels leading to lower overall energy consumption (energy saved = 0.6 * 103 MJ/ton of steel). (vii) Coal injection into blast furnaces (Oxy-fuel blast furnace process) The replacement of existing fuel injection with a coal injection system would reduce the coke consumption (energy savings potential up to 3 * 103 MJ/ ton of steel). One example


of this is the oxy-coal blast furnace process in which the fuel requirement is provided by coal and the retaining of physical and chemical contributions to the burden support, heat transfer and reforming of the oxidized gases are provided by coke. This is achieved by the injection of coal with oxygen into the blast furnace, thereby achieving high levels of coke and hot blast replacements. The maximum oxygen percentage in the blast, required to maintain a sufficiently high flame temperature, is 51%. (viii) Introduction of ultra high power EAF

It is more suitable to introduce the ultra high power EAF in large mini-mills. Energy saving of 10% as compared with ordinary EAF can be achieved along with the reduction in melting time and increase in furnace productivity. 3.2.2.2 Waste heat recovery

(i) Recovery in iron-making stage a) Waste heat recovery from sinter cooler The temperature of exhaust air from the sinter cooler is 300-350°C and the energy content of its sensible heat is equivalent to approximately 30% of the energy input into the sintering machine. The sensible heat can be recovered by following ways:

1. Recirculating Fans: - introduce the hot air to the ignition furnaces for use as combustion air

(energy saved = 20.92 - 41.84 MJ/ton of sinter). - introduce the hot air to the raw material layer for preheating (energy saved

= 41.84 - 83.7 MJ/ton of sinter). 2. Waste Heat Boiler:

- produce steam for processes, or - provide steam to feed the turbines for power generation (steam saved = 125.5 - 209.2 MJ/ton of sinter).

b) Waste heat recovery from dry quenching of coke The sensible heat of coke (temperature of about 1000°C) can be recovered by circulating non-oxidizing gas in a closed loop. The heat recovered can be used to generate steam or electric power by means of a heat exchanger (energy saved = 334.72 MJ/ton of coke). In comparison with conventional wet quenching, this process can improve the coke quality and environmental performance of the industry. c) Waste heat recovery in BF hot stove The sensible heat of BF hot stove gas can be re-used to preheat the combustion air and fuel gas (energy saved = 83.7 - 125.5 MJ/ton of pig iron).


d) Pressure recovery turbine for the top gas pressure in blast-furnaces The blast furnace top gas exits with a sufficiently high pressure which, after cleaning, may be expanded through a suitable recovery turbine to generate electricity. Up to 50% of the electrical energy required for blast compression can be recovered by this method. The power output depends on the BF and ranges from 8-15 MW (energy saved = 0.25-0.31 * 103 MJ/ton of steel). (ii) Recovery in steelmaking stage:

a) BOF gas (LD gas) recovery During the oxygen-blowing period of a BOF, a large volume of gas is generated. This gas contains up to 90% carbon monoxide, and can be recovered by using:

- Waste heat boiler, combustion type steam recovery system, in which the CO contained in the gas is completely burned using air and the sensible heat is recovered as steam (steam saved = 292.9 MJ/ton of steel).

- COG system, suppressed combustion type gas recovery system, in which the CO

contained in the gas is not burnt, but is recovered as latent heat (latent heat recovered = 836.8 MJ/ton of steel)

3.2.2.3 Self power generation

The on-site electricity generation on combined cycle mode by using the recovery gases as well as additional fuels can improve the overall energy efficiency (energy saved = 0.5 * 103 MJ/ ton of steel). 3.2.3 Long term measures

The long term measures involve modification of the system to obtain an improvement in the efficiency of the process. These are: (i) Direct steel making

- iron ore to steel in a single reactor - easier to control and reduced time to occur - reduced environmental problems.

The COREX technology, discussed under section 3.3 is one example of direct steel making. Another example is the O.R.F. Direct-Steel Process, in which a bed of fine magnetite superconcentrate, laid down on a traveling grate, is heated to about 980°C by hot flue gases and subsequently burnt in air drawn through the bed. This burning raises the temperature to about 1200°C causing the particles to sinter lightly together in a highly permeable bed. A reducing gas, consisting of carbon monoxide and hydrogen (3:1 ratio), is then passed


through the bed. The complete reduction to iron takes less than an hour and yields hot, porous, sintered iron, which is then stripped from the grate and rolled into steel sheet of about one tenth the thickness of the original bed. One limitation of this process is the requirement of iron ores which can be concentrated to a purity of 0.5 per cent gangue or less. (ii) Direct casting

- casting to material directly from the steel making furnace - no requirement of intermediate rolling - process develops unique properties of the product

The different energy efficiency and waste heat recovery measures are summarized in Table 3.2. Examples of such measures are available in:

- energy conservation plan for medium sized integrated steel plant (Figure 3.9) which reduces energy consumption by 20% through the implementation of conservation measures.

- principal measures taken by Nippon Steel Corporation (NSC) in its BF-BOF plants as shown in Figure 3.10.

3.2.4 Energy management program

The establishment of an appropriate organization (called Energy Center) at plant level can help to improve the energy efficiency of iron and steel industry. This Energy Center can:

- provide centralized control over the supply and demand of both primary and secondary energy;

- monitor the operating conditions of energy consuming, generating and distributing facilities;

- reduce energy cost by stabilizing the supply and demand of energy; - improve operation by maximizing the use of by-products.

Figure 3.11 illustrates the role of the Energy Center in channeling the energy flow in an integrated plant.

Energy Issues in the Iron and Steel Industry 29 27

Table 3.2. Energy efficiency and waste heat recovery measures

Prod. stage Energy efficiency increasing measures Energy Rank Waste heat recovery measures Energy Rank Coke plant

Automatic combustion control (ACC) Calorific value control of mixed gas Optimized temperature distribution in combustion chamber Automatic ignition of COG released

F B F B F B F B

Recovery of coke sensible heat (CDQ) Changing of dried coal COG sensible heat recovery Exhaust gas heat recovery

SE A F B S B F C

Sinter plant Particle size distribution control of ore and coke breeze ACC of ignition furnace (control of oxygen content in the waste gases, temperature and pressure) Increase bed depth

F B F C F B

Waste heat recovery from main exhaust gas Cooler waste heat recovery - Combustion air preheating for ignition furnace - Sinter mix preheating - WHB and/or power generation

S A F C F C SE A

Pellet kiln Adding dolomite (self-fluxing pellet) Increased efficiency of cooling zone

F B F C

Waste heat recovery from pellet cooler

F B

DR Preheating of recirculating gas In-site reforming Preheating of combustion air Gas flow pattern control in DR furnace Increased reducing gas temperature

- - F B - - F C - -

Waste heat recovery of reformer DRI latent heat recovery Hot DRI charging into EAF

F B - - E B

BF Burden distribution control Furnace condition control system Insulation of blast main Hot stove heating pattern control

F B F B F C F C

Top pressure recovery turbine Recovery of BFG bled Evaporative stave cooling Hot stove waste heat recovery

E A F B S C F A

BOF CC Automatic ignition of BOF-gas released Programmed control of ladle preheating Improve insulation of CC tundish

F C F C F C

BOF-gas recovery BOF-gas sensible heat recovery

F A S A

EAF

UHP Oxygen blowing

E B E B

Scrap preheating by waste heat

E C


Table 3.2. Energy Efficiency and Waste Heat Recovery Measures (Cont’d)

Prod. stage Energy efficiency increasing measures Energy Rank Waste heat recovery measures Energy RankHot rolling ACC

Optimized heating pattern Extension of furnace length Improved insulation of furnace wall/roof Double insulation of skid Use of hot rolling oil Higher speed rolling Increase in hot slab charging ratio and temperature Increase in hot direct rolling ratio

F B F B F C F C F C F C F B F B F A

Modification of recuperator Slab preheating by waste gas impinging Waste gas sensible heat recovery for steam Steam recovery by evaporative cooling of skid

F B F B S B S C

Cold rolling Steam saving by means of floats and well-sealed lids Dispensing with electrolytic cleaning Programmed heating of coil Extension of furnace length

S C SE B F B F B

Waste heat recovery from cooling water Combustion air preheating from batch type furnace WHB of non-oxidizing furnace

S C F C S B

Others Boiler combustion control Improved mixed gas supply by calorific value control Insulation of tank Power saving for fan and pump operation by rotative speed control

F B F B S C E B-C

Use of back pressure turbine generator Waste heat recovery of boiler Energy supply demand control system

E B F C All B

a/ Type of energy saved: F = fuel; E = electricity; S = steam b/ Rank (effect of measure on energy saving); A = major; B = medium; C = slight Source: NSC

Energy Issues in the Iron and Steel Industry 29

3.5

3

2

1

blastfurnacestovesimpr.

rehe

at fu

rnac

e m

oder

niza

tion*

soak

ing

pit m

oder

niza

tion

bell-

less

bla

st fu

rnac

e to

p

repl

ace

boile

r

blas

t fur

nace

gas

unde

rfiri

ng c

oke

oven

s

CU

MU

LATI

VE

CAPI

TAL

CO

ST (

$ pe

r ton

per

yea

r)

SIM

PLE

PAY

BA

CK

(ye

ars)

CUMULATIVE ENERGY SAVINGS (percent)

* These projects substantially overlap each other. Net total energy savings for the plan are 20%.

replacementof reheatfurnaces

Figure 3.9 Energy conservation plan for a steel mill, including capital cost, energy saving and economic performance


Cake Oven

Sintering Plant

Iron Ore

HSBF

Sint

ered

Ore

Coke

Bree

ze

Bell CokeC

okin

g C

oal B

FG

HotMetal BOF

LDG

ScrapOxygen, etc

Molten Steel

CCReheatingFurnace

HotRolling

ColdRolling

AnnealingFurnace

Cold RolledProducts

Hot RolledProducts

Coke Dry Quenching (CDQ) Steamand or Electricity Recovery

Coke Oven Gas (COG)Sensible Heat RecoveryFuel Pre-heating Coal Drying

BF Top Pressure RecoveryTurbine (TRT)

BOF Off-Gas (LDG)Sensible Heat RecoveryWaste Heat Boiler

Slab Pre-heating by Waste Gas impinging

Extension of Furnace engine

Installation of Partition Walls

Double Insulation of Skid Pipe

Optimization of Heat Pattern

Modification of Recuperator

Fuel

Sav

ing

Hot DirectRolling (HDR)Fuel Saving

Continuous Annealingand Processing Line

RecuperatorAir Pre-heating

Slag SensibleHeat Recovery

Hot Slab Charge (HCR)Fuel Saving

Lowering SlabDischarge Temperature

Waste Heat recovery of HotStove Air and/or Fuel Pre-heating

Waste Heat Recovery of Sintered oreAir Pre-heating, Steam or ElectricityRecoveryNotes:

Electricity and Steam saving Measures have been incorporated in all processes

Adopted measures and installed equipment

Under development

BOF Off-Gas (LDG)Recovery

COG

}

Figure 3.10 Selected measures for a BF-BOF plant at Nippon Steel Corporation


}{

{

Electricity18

Oil 12

Coal70

COG 14

BFG 15 LDG 3

EnergyCenter

13

62

49

10

Loss &Others

By-P

rodu

ctG

ases

By-ProductGases

Elec

trici

ty

Oil

20

17

12

WasteEnergy Recovery

Cooperative ThermalPower Plant

Oxygen, Nitrogen,Water, Compressed Air

Sold

Cake Oven

Iron Ore

Sintering Plant

Coke

Bree

ze8

Blast Furnace

Sint

er

Bell

Cok

e 41

Coki

ng C

oal

16 7

Oil

Inje

ctio

n 8

765

BCF

-1 16

Iron Making Division Steel Making Division Rolling Division

2 4 8 4

Hot DirectRolling

MoltenSteel

OxygenSubmaterials

ContinuousCasting Reheating

Furnace HotRolling

ColdRolling

AnnealingFurnace

Cold RolledProducts

Hot RolledProducts

Energy consumed =

Energy sold =

83

17

Oxygen, nitrogen, water,compressed air are expressedin terms of electricity, &steam in terms of by-productgases.

Process Boiler (Steam)

3

Purc

hase

d En

ergy

100

Hot Metal

(Unit of Energy: percentage of purchased energy)

Figure 3.11 Role of the energy center in an integrated steel plant


3.3 New Energy Efficient Technologies for Steel Making

New technologies for energy conservation, waste reduction and environmentally soundness in the iron and steel industry are introduced. These are mentioned below with their significant characteristics. (i) COREX Technology

The COREX technology is a direct steel making process with following significant advantages:

- elimination of coking plant through use of non-coking coal - elimination of agglomeration plants through the input of 100% lump ore - high operational flexibility with respect to production capacity, raw material

changes and stopping times - much lower investment cost per ton of installed hot metal capacity owing to its

compactness as compared to the conventional blast furnace route - better emission factors than the blast furnace options.

In the COREX technology, the coking plant is eliminated by replacing coke with a wide range of coals. The iron ore reduction and melting are separated into two reactors. The generation of reducing gas and the production of thermal energy from coal for melting occurs in the meter-gasifier, and the reduction of iron ore occurs in a shaft furnace operating at a pressure of up to 5 bar. The coal in the meter-gasifier comes into contact with a reducing gas atmosphere at a temperature of about 1500°C. Drying and de-gasification of the coal particles occur in the upper portion of the meter-gasifier. The energy intensity of a COREX/Direct reduction-Electric arc furnace is 18 GJ/t, as opposed to 25 GJ/t for B.F./Basic oxygen furnace, while most of the emission factors are also lower than those of its counterpart.

The cost of COREX technology is of the order of US$ 1900 per ton installed capacity and the annual variable cost is about US$ 320 per ton installed. The figures for BF-BOF option are US$ 1950 and 570, respectively. (ii) Direct-Current EAF

The technological progress of power electronics in recent years has made possible the manufacture of high-current rectifiers, thus opening scope for the development of DC-EAFs. This is an energy efficient and environmentally sound option for mini steel mills. It uses direct instead of alternating current in an electric arc furnaces with the following advantages:

- sharp reduction in top electrode consumption as compared to AC-EAF - reduction in electric power consumption due to elimination of cold and hot spots - reduction in refractories consumption - low noise level - high productivity as compared to AC electric arc furnaces.


(iii) New Melting Furnace (MECOF)Technology

- The new melting furnace is a hybrid furnace combining the advantage of both the basic oxygen furnace and the EAF. Based on the DC-EAF technology, this furnace incorporates elementary techniques for blowing variety of gases and powers through the furnace bottom.

(iv) Oxy/Coal Blast Furnace Process

- fuel is provided by coal - whilst retaining physical and chemical contributions to burden support,

productivity is increased - results in a higher top calorific value.

(v) Scrap Preheating Technology

- able to preheat scrap to high temperatures - solve the problem of white smoke and offensive odor - time ratio of transformer utilization to the total operating time can be increased

(v) High Speed Rolling Mills

- Lower discharge temperature of the reheat furnace load. - Reduced fuel consumption in the reheating furnaces. - Energy consumption of reheating furnaces lowered by 105-125 MJ/t, i.e., about

10%. - With a low discharge temperature of the billets, heavy reduction mills should be

used in the subsequent rolling stage(s). High speed rolling is an effective way to improve the productivity and reduce energy costs at the rolling stage. High speed rolling mills with large reduction capacity allow for a lower temperature at which billets, blooms or slabs need to be discharged from the reheating furnace in comparison to that for conventional rolling. 3.4. Concluding Remarks

In comparison with other industries, the recovery of waste heat can offer significant energy savings since the temperature levels of the processes in the iron and steel industry are quite high. Therefore, the exploitation of high potential of thermal recovery should be the first priority for the iron and steel industry to improve the energy efficiency of the industry. The adaptation of energy efficient sub-processes, change in current practices to reduce energy losses and change in input raw materials could lead to better efficiency of the industry. Electricity generation for on-site sufficiency or for sale by using waste heat as well as other fuels can lead to better utilization of energy resources at both macro and micro levels.


4. SOURCES OF POLLUTANTS AND POLLUTION MANAGEMENT

4.1 Sources and Characteristics of Pollutants

Dust and smoke emissions and other sources like smog that lead to atmospheric pollution, affect the human, animal and plant environment in many ways, besides deteriorating buildings and damaging machinery. The release of toxic discharges harms the respiratory and digestive systems and the skin and the eyes. Exhaust gases and vapors reduce visibility and penetration of sunlight. Plants are more susceptible to the deleterious effects of sulfur oxides, dust falls and humidity changes. Water pollution by industrial effluents represents a serious threat to man, fish, wildlife and vegetation. Such pollution by liquid wastes also causes serious difficulties in the operation and maintenance of water supply and storage, and sewer installations. The discharges and contamination that pollute air and water in the steel industry may be gases, liquids, solids, or a combination of these. They give rise to psychological, toxic and allergic reactions. Dust produced by many sources in the industry is irritating, toxic and harmful and becomes absorbed in the bloodstream in many cases. Inorganic and organo-metallic gases and fumes that may be irritants and asphyxiants cause damage and inflammation of the skin, eyes and respiratory track and prolonged exposure to some of them leads to fatigue and diseases. Figure 4.1 shows the sources of solid, water and air pollution. Figure 4.2 shows the major sources of pollutants in the form of a process flow diagram, along with the environmentally friendly technological options. 4.1.1 Wastewater

A series of process in this industry naturally brings in a variety of water pollution problems since the industry is a prodigious water consumer (about 150 to 200 ton/ton of steel produced). Most of this water is for non-consumptive use, namely for cooling furnaces, ancillary plant and equipment such as rolls, for cooling and cleaning gases, for cooling fuel burners and roof lances, for cleaning process dusts, ash, scales, etc., for operation of fire service and ventilation equipment, for circulation through condensers and so on. The consumptive and partly consumptive uses of water mainly relate to coke quenching, rinsing in pickling and cold rolling, steam generation and miscellaneous process additions, such as in mixing, grinding and separating. The water pollutants may be mineral matter, sulfurizing compounds, oxidizable constituents, organo-synthetic chemicals, inorganic substances, fertilizing elements and infectious agents. As shown in Figure 4.3, the common sources of water pollution in these integrated plants are phenols, cyanides, ammonia and chlorides (in the cookeries), ore and coke solids and sulfur compounds during ore preparation, washing and sintering; dissolved constituents and impurities during pelletizing; dust and heated water from blast furnace cooling water; ammonia, cyanides, phenols and suspended solids during gas cleaning and slag quenching - all of these resulting from the iron making process; sulfuric acid and iron solids from steel

Sources of Pollutants and Pollution Management in the Iron and Steel Industry 35

making furnaces; tar, heated water and solids from ancillaries of steel works; dust, heated water and iron salts in cooling water; oils, dry sediments, solids, chemical impurities and scale particles in hot and cold rolling wastewater; ferrous hydroxide, ferric deposits, iron solutions and oxygen reduction during pickling - all these caused by the steel works; and dust, heated water, sulfuric acid and solids from foundries, locos and boilers and ancillary plants. Wastes are treated by re-circulation, evaporation, benzole extraction, distillation, sedimentation, neutralization, skimming, flotation and aeration. In the conventional process without recirculation, wastewater (including cooling operations) is generated at an average rate of 80m3 per ton of steel. Major pollutants present in the wastewater generated from pig iron manufacture include total organic carbon (typically 10mg/l), total suspended solids (7000 mg/l), dissolved solids, ammonia (up to 1000 mg/l), cyanide (15 mg/l), fluoride (1000 mg/l), and COD (200 mg/l). Major pollutants from steel manufacturing using the BOF include total suspended solids (typically 4000 mg/l), lead (8 mg/l), chromium (5 mg/l), cadmium (0.4 mg/l), fluoride (20 mg/l), and oil and grease (World Bank, 1995). In gas wash water concentration of suspended solids varies considerably, not only from plant to plant but even hour to hour in the same plant. A typical range of suspended solids is 5000 to 20000 ppm (parts per million) (ESCAP, 1992). 4.1.1.1 Iron ore concentration

A large amount of slurry water with tailings must be disposed of. Some of the tailings release asbestos particles which are of a small size (approximately that of bacteria or colloidal clay) such that they disperse completely and settle minimally. Asbestos is a complex combination of several hydrous silicate minerals that contain primarily calcium, magnesium, sodium, iron and aluminum. The wastewater coming from the sintering shop contains ore and coke up to 30 g per liter. 4.1.1.2 Coke process

The major wastes from preparation of the coke product itself come from the quench tower, where the hot coke is deluged with water. The coke dust present in this quenching water is called “breeze” and is commonly recovered from the water. Important wastes from this phase come from ammonia still, the final cooler and from the pure still (these wastes are numbered in Figure 2.3), where products such as benzene, toluene and xylene are made from the crude naphthalene. Of all the noxious effluents that result in the cooking process, ammonia liquor and ammonia still liquor (spent liquor) pose the major treatment and disposal problems in regard to both quality and complexity. Phenol and oxygen demanding matter are the primary contaminants. These wastes average 200 liter/ton coal feed (Sell, 1992). A summary of the major constituents of these coke plant wastes is given in Table 4.1.


Ore & scrap

Crushing

Sintering

Crushing

Coking

Blast furnace

Steel FurnaceCoating

Steel Rolling,Coating,etc

Coal

Lime Stone

Pig Iron

Finished Steel

Particulates

Particulates

Particulates

Particulates

SS, TDS, Acids

CO, NH3, SOx, NOx

SS, TDS,Dissolved ChemicalsAcids

SS, TDS,Dissolved ChemicalsAcids

CO, NH3, SOx, NOx

Particulates

Slag

Dissolved Chemicals,SS,Acids

LegendSlag

Air Pollutions

WaterPollutions

Figure 4.1 Sources of pollution in a steel plant


RAW MATERIAL Iron Ore Limestone MetallurgicalCoal Scrap



Ingot Casting

ContinuousCasting

LiquidSteel

Primary Rolling

Hot Rolling Mill

Cold RollingMill


Pipes


Bars, Pipes, Rods

IRON MAKING

STEEL MAKING

CASTING &PRIMARY ROLLING

ROLLING &FINISHING

FINAL STEELPRODUCT

Process Flow

PigIron




Ingot Casting

ContinuousCasting

LiquidSteel

Primary Rolling

Hot Rolling Mill

Cold RollingMill


Pipes


Bars, Pipes, Rods

Effluent Flow/Emissions

PigIron

GasPurification to own plant

Coke oven gas

Crude gas

GasCleaning to gas delivery

Blast furnace gas

B.F

. gas

enric

hmen

t

enric

hed

gas

Particulates

Particulates,SO2

H2SO4

Particulates,NH3, CO,SOx, NOx

SS, TDS, Acids,Dissolved chemicals

BF : Blast furnaceBOF: Basic oxygen furnaceOHF: Open hearth furnaceSS : Suspended solidsTDS: Total dissolved solids

SS, TDS, Acids,Dissolved chemicals

Particulates, NH 3,CO, SOx, NOx,Hydrocarbons

Crude gas

Water

SS, NH3, Phenol,Cyanides

DustRemoval

Sludgeto sintering

plant

SS, Acids, Dissolvedchemicals

NOx, SOx

SS, Acids, Dissolvedchemicals, Oils,

Scale & Sediment

SS, Acids, Dissolvedchemicals, Oils,

Scale & Sediment

Figure 4.2. Process flow/emissions and mainly environmental technologies forintegrated iron and steel industry

Environmental Technologies

E.1. Dust Collection & Handling SystemsE.1.1. CylconesE.1.2. Wet scrubbersE.1.3. Electrostatic precipitators for sinter plant

F.1. Direct Reduction FurnaceF.2. Dry quenching of coke


BLAST FURNACE

Iron worksCoke ovens Steel works Ancillaryunits

(Phenals,cyanides,ammonia,chlorides)

PICKLING WASTEIron solution, acidsinsoluble ferroushydroxides, ferricdeposits, oxygendepleted water

WASTE WATERHOT & COLDROLLINGSolids, chemicalsimpurities oils,scale & sediments

STEEL MAKING(Iron oxide and H2SO4 and flouride)

ROLLING ANCILLARIES(Heated water, tar and solid impurities)

WATER FORCOOLING(iron salt,dustsand heated water)

COOLING WATER(Dust and heatedwater and floatingimpurities)

QUENCHINGOF SLAG(solids and H2SO4)

OREPREPARATOIN

WASHINGOF ORE(Solidwastes)

SINTERING(Solids like Ore andcoke particlesand H2SO4)

PELLETIZATOIN(Ore impuritiesmainly dissolved)

IRON AND STEELFOUNDRIES(Heatedwater dust)

LOCO SHOPS(grease,oils,impurities andheated water)

BOILER PLANTS(Heated water,solids and H2SO4particles,etc)

Fig 4.3. Different origins of polluted water in the iron and steel industry

GAS CLEANING(phenol,ammonia,suspended,solids and,cyanides)


Table 4.1. Characteristics of Coke Plant Wastewater

Characteristic Source of Waste

Ammonia StillFinal Cooler 1 Pure Still Combined

BOD5 3974 218 647 53 - 125 2

Total suspended solids (ppm) 356 125 89 3

Volatile suspended solids (ppm) 153 97

Organic and NH3 - N (ppm) 281 14 20

NH3 - N (ppm) 187 10

Phenol (ppm) 2057 105 72 6.4 4

Cyanide (ppm) 110

pH 8.9 6.6 1 No circulation. 2 Depending on composting technique. 3 Average of 11 daily 24-hour composites, including coke breeze. 4 Single-catch sample. (Source: Nemerow, 1978)

4.1.1.3 The blast furnace

The water pollution from this stage results from employing wet method for air pollutant removal. The wet scrubbing of blast furnace gas evolves water laden with flue dust. The wet scrubbers are down-flow water sprays which clean the dust from the up-flowing gases, an operation which is usually an intermediate stage between dry (or cyclone) dust separation and final electrostatic precipitation of the remaining fine particles. Secondary gas washers or precipitators are periodically cleaned by flushing with water, thus adding to the flow of discolored water. The wet-scrubber effluent contains flue dust solids, composed of iron oxide, alumina, silica, carbon, lime and magnesia. The amount of each constituent, in comparison with the total quantity of dust, varies with the type of ore used in the furnace, conditions of the furnace lining, the quality of coke used, the number of furnace in blast, the amount of air being blown, etc. Fe2O3 comprises about 70% and silica 12% of the flue dust content. Some of the physical characteristics of flue dust waste water are given in Table 4.2.

Table 4.2. Characteristics of Wet Scrubber Effluent


Characteristics Value or concentration Suspended solid content Range (ppm) Percent by weight passing 100 mesh sieve Percent by weight passing 200 mesh sieve

500 -4500

86 -99 74 -97

Temperature (oC) 38 - 50 pH 6 - 8 Specific gravity 3 - 3.8

Source: Nemerow,1978

4.1.1.4 Pickling process

The process produces a waste called “pickling liquor”, composed mainly of unused acid and the iron salts of the acid (Fe+++ and Fe++). The acid reacts with the iron salts, forming FeSO4. As the acid is used, it becomes weaker and must be renewed. However, at a point, the concentration of FeSO4 increases to such a degree that it inhibits the action of even a high concentration of sulfuric acid. At this point, the pickling liquor must be discharged and replaced by a fresh batch of sulfuric acid. Since the steel products must be rinsed in water after they leave the pickling tank to remove all trace of acid, the rinse or wash water eventually becomes quite acidic and must also be discarded. The volume of rinse water is 4 to 20 times that of actual pickling liquor. Wash water contains 0.02 to 0.5% H2SO4 and 0.03 to 0.45% FeSO4, as compared with 0.5 to 2.0% H2SO4 and 15 to 22% FeSO4 in the pickling liquors. Thus, H2SO4 and FeSO4 in these ranges of concentration are the major contaminants. 4.1.2 Gaseous and particulate emissions

The general sources of air pollution are smoke, dust and hydrogen supplied in coking operations (such as charging and discharging, carbonizing, quenching and byproducts); dust, fume and sulfur dioxide in the steel shop (which include steel making furnaces, rolling mills, ancillaries and mill furnaces); dust and sulfur dioxide in the iron shop in relation to ore preparation, crushing and screening, ore drying and sintering and blast furnace charging, gas cleaning slag disposal and pig casting; and dust and sulfur dioxide combined with smoke during the ancillary operations (as are involved in the working of iron and steel foundries, boilers and locos). Figure 4.4 briefly indicates the above sources which pollute the air. Air contains oxides such as NO, NO2, N2O, etc., some of which are noxious. Such oxides are generated in processes which involve combustion at high temperatures. The heating furnaces, sintering plants, and coke ovens are major sources of nitrogen oxides. Air emission from pig iron making includes particulate matter (PM) (typically 15 kg/ton of steel manufactured), sulfur oxides (SOx) (1.5 kg/ton of steel), nitrogen oxide (NOx) (0.5 kg/ton of steel), dioxins (mostly from sintering operations), hydrocarbons, carbon monoxide, and hydrogen fluoride.


IRON WORKS

COKE OVENS

STEEL WORKS

ANCILLARYUNITS

BLASTFURNACE

CARBONI-ZATION(fumes)

QUENCHING(fumes dust)

BYPRODUCTS(hydrogensulphide)

CHARGING (fumes)

STEELMAKING(dust,fumes, SO2)

ROLLING (dust)

ANCILLARIES (dust)

MILLFURNACE(SO2)

FURNACE TOP (dust)

GAS PLANT (dust)

SLAGDISPOSAL(dust,SO2)

PIGCASTING (dust)

OREPREPARATION

CRUSHINGANDSCREENING (dust)

ORE DRYING (dust)

SINTERING(dust,SO2)

IRONFOUNDRIES(dust,SO2)

STEELFOUNDRIES(dust,SO2)

BOILER-SHOPS(dust,SO2,smoke)

LOCOSHOPS(fumes,smoke)

Fig 4.4 Various sources of air pollution in the iron & steel industry


Air emission from steel manufacturing (by BOF) may include PM (typically 15 kg/ton of steel), chromium (0.8 mg/Nm3), cadmium (0.08 mg/Nm3), lead (0.02 mg/Nm3), and nickel(0.3 mg/Nm3). In sintering process, air gets heated up and becomes laden with dust, moisture and SO2. Particulates and gases discharged from various processes are summarized in Table 4.3.

Table 4.3. Particulates and Gases Discharged from Iron and Steel Industry

Type of discharge

Coke plant

(kg/ton of coal)

Sinter plant

(kg/ ton of

sinter)

Blast furnace

(kg/ton of iron)

BOF (kg/to

n of steel)

EAF (kg/to

n of steel)

Hot rolling (kg/to

n of steel)

Cold rolling

(kg/ton of steel)

Particulates 30 - 50 15 - 25 0.2-1.6 30 - 33 3.0 - 20 0.4 - 3.5

3.0 -7.0

SO2 0.2 - 1.0 1.0 - 12.0 - - - - - Hydro carbons 4.0 - 8.0 - - - - - - Hydrogen sulfide

0.1 - 0.8 - - - - - -

Hydrogen cyanide

0.1 - 0.6 - - - - - -

Aerosols - - - - - - - Source: Asian Institute of Technology, 1989 4.1.2.1 Preparation of iron ore

Procurement and preparation of iron ore gives rise to problems of air contamination by dust, mineral and metal sublimates, grit particles, etc., depending on their size, nature and concentration and the time of exposure. For example, handling of bulky, friable materials through various stages and their large scale transport, loading and unloading greatly increase the problems by releasing heavy dust and particulates, smoke and emissions from the vehicles moving the materials. Due to natural causes, wind-borne dust is also caused from dumps, storage heap, and mucky roads in the area. 4.1.2.2 Coking

The main emission sources are: storing, heaping, loading and unloading and handling; crushing, screening, blending and piling of coal and coke; charging, pushing and discharging of coke ovens; and quenching of hot coke. Combined pollutants such as coal and coke dusts, grit, smoke, particulates, mists along with volatiles which consist of hydrocarbon vapors, carbon monoxide, ammonia, sulfur dioxide and many other organic and inorganic compounds, are emitted in the process. Leakages and coal charging, coke pushing and quenching operations are major sources of gaseous emissions (smoke and particulate) from byproduct coke ovens. These emissions vary widely depending on the oven conditions, coal characteristics and operating practices


at each plant. Hydrogen sulfide, hydrogen, methane, CO, CO2, N and carbon disulfide are present in the gas. When coal is charged into the hot oven, the gases in the oven are displaced, and the coal immediately begins to volatilize. Particulate matter is emitted through the charging holes in large rushes of smoke at this time. Discharging of the ovens produces grit and dust of a course nature, as also gases due to partial carbonization at times. Quenching also causes dust, grit and small but densely moist droplets. During the initial coal preparation, the grit and dust that escape into the air almost amount to 0.5 kg per ton coal. Coal cleaning with air to eliminate undesirable materials cause copious dust from the dryers and pneumatic cleaners. In coal carbonization installations, tar removal from the raw coke gas collectors causes noxious air pollution. 4.1.2.3 Blast furnace operation

During smelting of iron ore in blast furnaces, particulates consisting of particles of iron ore, sinter and coke, are thrown out with the exit blast furnace gases, which primarily contain CO and SO2. The sulfur remaining in the coke oxidizes to form SO2. The blast-furnace gases leaving the furnace at the top contain large amounts of particulates, namely dust (with about 30% iron, 15% carbon, 10% SiO2 and small quantities of Al2O3, MnO, CaO and other materials) (Bhattacharya, 1975). 4.1.2.4 Steel making

The open hearth furnace and BOP remove impurities through oxidation. Involving reaction at high temperatures and inflammable conditions, the processes give rise to iron vapors which get oxidized and enter into the waste gases, appearing as highly dense emissions of reddish/brown color. It also contains oxides of carbon and silicon. These are a source of intense air pollution and render waste gas cleaning very difficult. In electric furnaces, dust, fume and grit are thrown out due to the exposure of molten steel to extremely high temperatures. The carbon which is added to stir and cleanse the metal, gets oxidized and gives rise to carbon monoxide emissions. During rolling mill operation scarfing is the main source of air pollution. Surface preparation using oxygen jets produces iron oxides; washing by water jets generates water vapor. 4.1.3 Solid waste generated

Compared to the air and water pollution in this industry, the solid wastes generated are minimal. Iron ore concentration, furnace and rolling mill operation are major sources of the solid waste. Slag (from blast furnace and steel melting shop), rubbish and kish (from steel shop pit sides and the mixer, foundry and special casting bays), coal rejects, flue dust, cinder, broken refractors, fine coke breeze, lime dust, rejected mill scale, etc., are some of the solid wastes from this industry. The waste sand and tailings come from the iron ore concentration. Tailings themselves have no nutrients, have poor soil texture and contain


many fines. During the blast furnace operation very hard and fine “coke breeze” is produced from the cooking process. This coke is very difficult to recycle. From the rolling mill operation large amount of solid wastes are produced which mainly consist of chipping and so forth. Treating the wastewater from the process generates heavy sludge consisting of hazardous material which should also be disposed of. Process solid waste from the conventional process, including furnace slag and collected dust, is generated at an average of 500 kg/ton of steel, of which 30 kg may be considered hazardous based on the concentration of heavy metals present (World Bank, 1995). 4.2. Current Pollution Abatement Strategies and Technologies

4.2.1 Air pollution control

In order to combat the menace of air pollution and suppress and control harmful fumes and other gaseous discharges produced in the iron and steel plants, several methods and type of equipment are being employed. The grit and dust from preparation of iron ore, modern purpose-designed bulk materials handling methods and machinery have proved to be definite aids. In most present day plants, large scale use of cover-mounted tipplers, belt conveyers, etc., are being made in addition to water sprays, wind-diverts, grit detention devices, etc. For example, the coke ovens of major integrated works are equipped with air and gas cleaning devices such as dust collectors, cyclones and settlers, scrubbers, smoke stacks with leak-proof vents and shutters. Similarly, the sintering plant is equipped with dust catchers and cyclones, fans, precipitators and scrubbers, gas cleaning apparatus, suction and vibrating screen devices (on sintering stands), for air cleaning and dedusting systems (use of additional devices such as precipitators and filters, diffusers, de-sulfurizers and absorbers is definitely necessary). An ore rich in iron and low in sulfur content, when used in the sinter blend, will tend to lessen the pollution effect of sulfur dioxide. Dry electrostatic precipitators are also used to clean the sinter strand discharge and exit gases, in order to reduce dust and water vapor. The sulfur dioxide content in these gases being very low, electrostatic precipitators serve well for all purposes. Pelletization gas and dust discharges are cleaned by cyclones and scrubbers. Large quantities of fume are given out from the sintering process. The fume is cleaned in battery cyclones and then led to the atmosphere and dispersed through tall chimneys. Further, plenum and exhaust type ventilators and arrangements for dedusting, washing and hydraulic transportation of wet dust are being provided. In the iron making process, cleaning is adopted as a rule; large scale use is made of dust-suction, precipitator and separator devices. Since the blast furnace gas dust contains a high amount of iron and carbon dust which have to be recovered for recharging into the furnace as sinter, and the dust-free gas is used as fuel for coke ovens, stoves and boilers, the gas cleaning plants are quite elaborate. The gas is cleaned in two stages after it passes through the dust catcher, in the gas washers and in the electrostatic precipitators. Cyanide ions are removed by several methods such as oxidation and aeration and conversion into salts.


Temperature reduction of gases, for example blast furnace gases, is achieved by means of scrubbers and spray chambers. Coke oven gas is washed with water, acid and oil. The water removes tar and dust and cools the gas; the acid removes and recovers ammonia (usually as ammonium sulfate) and the wash oil absorbs organic chemicals such as benzene, toluene and xylene. The gas is finally treated to remove sulfur compounds. In case of steel making, efficient cleaning of the gases emitted is necessary because many refining processes, each having its own special characteristics, are employed. Use of oxygen-blown converters, open hearth furnaces and electric furnaces leads to large quantities of extremely fine dust particles and smoke. For suppressing and cleaning these, dry and wet methods using scrubbers are generally employed. Hood devices are used for dust collection, and cloth filters for cleaning fumes in the case of electric furnaces (for controlling the emissions and removing the dust accumulations periodically and more efficiently, roof-mounted hoods equipped with filter bag compartments are quite effective). In the case of LD converters, the selection of the dust collection device depends very much on the converter size, maximum rate of carbon oxidation, quantity of air added and amount of steam produced in cooling. Different devices which include dust collectors, filters, washers, continuous steam generators, heat exchangers and flues, sludge collectors, etc., are used for trapping and cooling the exhaust gases and dust from the converters before they are subject to cleaning. In steel making, the wastewater not only contains suspended matter but slag and acidic constituents. Further, during oxygen blowing, the converters let out a lot of dusty gas with metal sublimates. This gas is cleaned and used as fuel for waste heat boilers. The gas first passes through a hood chamber to the cooler where it is cooled. Evaporative type heat plates are also provided. Scrubbers, venturi tubes and centrifugal collectors are used for final cleaning of the gas. For preventing gas leakages in the converter and gas ducts, nitrogen is supplied to the seals. The flue gases from power plants are treated to remove ash by wet catchers and then vented outside. Fumes, sublimates and metal particles from various steel mill processes are cleaned in specially equipped cleaning plants and then led away to stack. Apart from all these measures, the steel townships are generally separated from the plant site by a wide green belt which helps maintenance of hygienic air. Provision of cooling ponds further helps to improve the environmental conditions in the area. Table 4.4 shows the emission standard requirements by the World Bank for projects financed by it. Also it further states that dilution of emissions to achieve these requirements is unacceptable.

Table 4.4. Emissions from the integrated iron and steel manufacturing Parameter Maximum Value


Particulate matter (PM) (mg/Nm3)

50

Sulfur oxides (SOx) (mg/Nm3)

500

Nitrogen oxides (NOx) (ng/J) - coal fired - fuel oil fired -natural gas fired

260 130 86

Fluorides (mg/Nm3) 5

4.2.2 Water pollution control

Treatment alternatives for primary and secondary controls of wastewater from iron steel industry are presented in the Figures 4.5 and 4.6. The primary method of treatment of by-product coke-plant wastes is to use recovery and removal units with high efficiencies, phenol being the main contaminant recovered. The BOD can be reduced by one-third by the practice of re-circulation and reuse of contaminated waters, and by-product recovery may be undertaken for profit in the case of such materials as ammonium sulfate, crude tar, naphthalene, coke dust, coal gas, benzene, toluene, and xylene. Quench water is usually settled to remove coke dust, and the supernatant liquor from the settling tanks is reused for quenching. Gravity separators are used to remove free oil from the wastes of benzole stills, since the emulsified oils are generally not treated and without separation the free portion of the oil would reach the sewers. Final cooler water is also re-circulated to reduce the amount of phenol being discharged to waste. Phenol is recovered primarily to prevent pollution of streams and to avoid the nuisance of taste in water supplies. Phenols may be removed by either conversion into non-odorous compounds or recovery as crude phenol or sodium phenolate, which have some commercial value. The conversion may be either biological (activated sludge or trickling filtration) or physical (ammonia-still wastes used to quench incandescent coke, a process which evaporates the NH3). Although certain concentrations of phenol (0 to 25 ppm) may be handled by biological units, dilution with municipal sewage is a good idea, since this provides a buffering and diluting medium. The Koppers dephenolization process lowers the phenol content by 80-90% in ammonia-still wastes. The process is essentially a steam-stripping operation, followed by mixing in a solution of caustic soda and renewing pure phenol with flue gas (see Figure 4.7). In treating flue dust, sedimentation followed by thickening the clarifier overflow with lime to encourage flocculation is found most effective for removing iron oxide and silica. Ninety to 95% of the suspended matter settles readily and does so within a one-hour period, the resulting effluent having less than 50 ppm suspended solids. Primary and secondary (lime-coagulated) thickened sludge is also obtained, which can then be lagooned without creating any problem. Figure 4.8 gives details of a typical blast-furnace wastewater treatment process.


Caking

CoolingTower

Settling Pond(ammonia)

Dephenalizer(with oilskimmer)

NeutralizationTank

SinteringBasic Oxygen

Furnace

CoolingTower

Thickener Settling Pond

Rolling

Cooling Tower

Blast Furnace

Vacuum Filter

Settling Pond(with oilskimmer)

ContinuousCasting Acid Picking

Scale Pit(with oilskimmer)

Flat BedFiltration

Cooling Tower

NeutralizationTank

Alkaline WasteRinse water

low pH

Sludge FeOH

Effluent Solids Effluent Filter Cake toSinter Plant

Effluent Effluent Effuent Solids to Land-fill or Sinter Plant Effluent

Figure 4.5. Primary wastewater treatment system

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

28

29

30

31

32

33

36

37

35

b

A B, C, D E

F

L, I, H K, M J

Effluent

Solids Solids

1. Cooling tower2. Equalization basin 3. Free ammonia still4. Dephenolizer5. Desulfuriazation unit6. Fixed ammonia still7. Neutralization tank8. Final settling pond9. Final cooling tower10. Cooling tower

11. Settling pond12. Thickener13. Thickener14. Vacuum filter15. Settling pond16. Coagulation tank17. Flat bed filter18. Settling pond19. Equalization basin 20. Settling pond

21. Clarifier22. Neutralization tank 23. Aeration24. Extended aeration 25. Scale pit 26. Clarifier27. Vacuum filter28. Acid waste holding tack29. Neutealization tank

30. Patash31. Lime32. Acid33. Polyelectrolyte34. Air35. Air36. Alkaline waste37. Na2S2O5

a

27

34

Figure 4.6 Secondary wastewater treatment system


BLAST FURNACE

Iron worksCoke ovens Steel works Ancillary units

Phenals, cyanides, ammonia, chlorides

(Phenals, cyanides, ammonia, chlorides)

PICKLING WASTE Iron solution, acids insoluble ferrous hydroxides, ferric deposits, oxygen depleted water

WASTE WATER HOT & COLD ROLLING Solids, chemicals impurities oils, scale & sediments

STEEL MAKING (Iron oxide and H2SO4 and flouride) ROLLING

ANCILLARIES (Heated water, tar and solid impurities)

WATER FOR COOLING (iron salt,dusts and heated water)

COOLING WATER (Dust and heated water and floating impurities)

QUENCHING OF SLAG (solids and H2SO4)

ORE PREPARATOIN

WASHING OF ORE (Solid wastes)

SINTERING (Solids like Ore and coke particles and H2SO4)

PELLETIZATOIN (Ore impurities mainly dissolved)

IRON AND STEEL FOUNDRIES (Heated water dust)

LOCO SHOPS (grease,oils, impurities and heated water)

BOILER PLANTS (Heated water, solids and H2SO4 particles,etc)

Fig 4.3. Different origins of polluted water in the iron and steel industry

GAS CLEANING (phenol, ammonia, suspended, solids and, cyanides)

NH3Still Waste

Steamstripper

Solutetank

NaOHDephenolizedliquid

Flue gasNa2CO3

Sodium phenolate

Phenol Figure 4.7. The Koppers Dephenolization Process using steam, caustic soda and

flue gas

Figure 4.8. Blast furnace waste water treatment process

The washwater separated from the sludge is re-circulated after cooling and sludge is used for sinter preparation. In the case of steel making, the polluted wastewater in circulation is cleaned by neutralization and precipitation of fine sediments (there is need for the use of equipment which intensify cleaning of suspended matter by magnetic and other principles). The treatment of pickling liquor is a problem of considerable magnitude. For most small steel plants, the recovery of by-products from waste pickling liquor is not economically


feasible and they neutralize the liquor with lime. However, some companies do obtain by-products from this waste, namely copperas and FeSO4.H2O; copperas and H2SO4; FeSO4.H2O and H2SO4; Fe2(SO4)3 and H2SO4; Fe+++ and H2SO4; iron powder; Fe3O4 for polishing or pigments; Fe3O4 and Al2(SO4)3. The recovered ferrous sulfate is usually marketed as a coagulant for chemical treatment of sewage. However, in the developing countries of Asia, the disposal of recovered ferrous sulfate still presents a problem (ESCAP, 1992). The Blaw-Knox-Ruthner process for the recovery of sulfuric acid involves concentration, by evaporation, of waste pickling liquor before it is discharged to a reactor, where anhydrous hydrogen chloride gas is bubbled through it, reacting with ferrous sulfate to produce H2SO4 and FeCl2 (see Figure 4.9). The ferrous chloride is separated from sulfuric acid (which is returned to the pickling line) and is converted to iron oxide in a direct-fired roaster. This liberates HCl which is recovered by scrubbing and stripping and is then recycled to the reactors.


Ore & scrap

Crushing

Sintering

Crushing

Coking

Blast furnace

Steel Furnace Coating

Steel Rolling, Coating,etc

Coal

Lime Stone

Pig Iron

Finished Steel

Particulates

Particulates

Particulates

Particulates

SS, TDS, Acids

CO, NH3, SOx, NOx

SS, TDS, Dissolved Chemicals Acids

SS, TDS, Dissolved Chemicals Acids

CO, NH3, SOx, NOx

Particulates

Slag

Dissolved Chemicals, SS,Acids

Legend

Slag

Air Pollutions

WaterPollutions

Figure 4.1 Sources of pollution

Figure 4.9. Blow-Knox-Ruthner process for acid recovery from spent pickle liquor (a) Process flow diagram; (b) Chemistry of the process


Neutralization of pickle-liquor waste with lime is costly, because there is no salable end-product and there is a voluminous, slow-settling sludge which is difficult to dispose of. Neutralization takes place in four stages:

- formation of ferric hydrate with a pH below 4, - formation of acid sulfate, - formation of the ferrous hydrate with a pH between 6 and 8, - formation of the normal sulfate.

Calcium and dolomite lime are the least expensive neutralizing agents, caustic soda and soda ash being too expensive for such a purpose. For neutralization, dolomitic lime is preferred because of its higher basicity factor compared with lime and the lesser volume of sludge that is finally produced. Three areas of change in the pickling-waste problem are improvements in the treatment of waste from pickling with H2SO4; a new HCl pickling operation; and a new dry de-scaling operation. New treatment methods for H2SO4 pickling include deep well disposal, with a removal efficiency of 85% (based on the fact that the rinse water is not treated and small percentage of the pickle liquor in the well may escape as pollutant), and ion exchange, which has a 85% removal efficiency. Hydrochloric acid wastes are treated by deep well disposal and by neutralization. Deep well sequestering is presently one of the more popular disposal methods. If the geology of the site is appropriate so as not to allow any ground water contamination, a well may be drilled and appropriately cased and then used for relatively low cost. Simple neutralization of the liquor of a pH of about 7 is easily done, but it creates some problems. A particular difficulty is that the solids that form (for example ferrous hydroxide) contain a large percentage of water. This sludge must be thickened in lagoons before final disposal. Since the pickling of one million tons of steel can generate 200,000 tons of wet sludge, this method is feasible only for those plants having quite large areas used for this purpose. Sophisticated neutralization techniques are required if any recovery is desired. A third method of treatment is regeneration, which consists of the following processes: the pickle liquor is pumped to a spray roaster where water and free HCl in the pickle liquor is quickly driven off; the crystal descends inside the roaster while an increased temperature gradient roasts it, producing iron oxide and hydrogen chloride; the iron oxide is collected from the bottom of the roaster; some iron oxide is discharged in the gas and a cyclone is used to collect it; finally, the dry hydrogen chloride is recovered as HCl. Abrasive de-scaling used on cold-rolled strips is done on two machines. The first uses steel spheres about 0.25 mm in diameter; the second uses even smaller angular grit. Both abrasives are cleaned continuously and re-circulated. The suggested treatment for coke plant wastes are given below:


(i) NH3 still

- recovers sodium phenolate with NaOH during steam distillation (phenol is subsequently obtained by passing flue gas through),

- re-circulates and reuses the contaminated NH3 still wastewater for quenching and water sprays for primary and final coolers,

- recovers (NH2)SO4 by making acid with H2SO4.

Biological treatment can be used to remove BOD and possibly to oxidize CN to CO2 and NO2. (ii) Final cooler

- re-circulates final cooler water, - combines the blowdown from this cooler with residual NH3 still waste, and

subjects both to biological treatment. (iii) Pure still

- settles to remove suspended solids and free oil, - sends supernatant (which contains some emulsified oils and BOD) for biological

treatment if it is a serious consideration for ultimate disposal. According to a World Bank report (1995), 90% of the wastewater generated can be reused. Table 4.5 shows the effluent standard requirement by the World Bank for projects financed by it. Also discharged wastewater should in all cases be less than 5 m3/ton of steel manufactured and preferably less than 1 m3/ton of steel.

Table 4.5. Effluents from the integrated Iron and steel Manufacturing Parameter Maximum value

pH 6 - 9 Total suspended solids (mg/l) 50 Oil and grease (mg/l) 10 COD (mg/l) 250 Phenol (mg/l) 0.5 Cadmium (mg/l) 0.1 Chromium (total) (mg/l) 0.5 Lead (mg/l) 0.1 Mercury (mg/l) 0.001 Zinc (mg/l) 2 Cyanides (total) (mg/l) 0.2 Temperature increase ≤ 3oC*


* The effluent should result in a temperature increase of no more than 3oC at the edge of the zone where initial mixing and dilution take place. Where zone is not defined, use 100 m from the point of discharge (Source: World Bank, 1995).

4.2.3 Solid waste reduction

As per the recommendation of World Bank, for projects funded by it, slag generation rates should be between 70 and 170 kg/t of steel manufactured; however, this will depend on the impurity content of feed materials. Approximately 65% of slags from steel manufacturing can be recycled. The slag may be used as construction materials, where possible, if it cannot be reused in the process; slag with more than 4% free lime can be used for iron making or in other manufacturing process. Zinc recovery may be feasible for collected dust. Also, sludges should be disposed off in a secure landfill after the stabilization of heavy metals. 4.3. New and Alternative Pollution Control Technologies

4.3.1 Direct reduction

A direct reduction process generally involves drying, crushing, and preheating the ore, which must contain about 68% Fe, and then injecting the ore into a reducing column. One of most efficient reducing gases is hydrogen. This converts iron oxides directly to metallic iron, which can then be further processed in electric furnaces. There are several definite advantages for direct reduction of Fe. The blast furnace consumes approximately 50% of all the energy used in the steel production. The blast furnace process also adds carbon to the Fe, and this must subsequently be removed. In addition, blast furnace generates some of the most serious environmental problems of the industry. However, a limitation of direct reduction technologies is the requirement of high quality iron ore. The trend towards small facilities, often producing specialty steels, enhances the applicability of general process. A wide variety of direct reduction techniques to produce iron for steel making has been developed of which the COREX technology, discussed in previous section, is the most significant one. The key environmental advantage to all of these processes is to avoid the use of coke. A number of steel companies are modifying their blast furnaces, rather than installing direct reduction process at this time, in order to reduce the use of coke. This can be done by injecting coal or other fuels into the combustion zone. Coal injection can, for example, reduce the coke used from 400 -450 kg/ton of hot metal to 225 - 275 kg/ton. 4.3.2 Direct steel-making

According to a study conducted by American Iron and Steel Institute, the next generation of steel-making process will be based on “inbath” smelting technology. Inbath technology is radically different from conventional treatment methods. The driving force behind its development has been based on both effluent/emission considerations and energy conservation.


The inbath smelting technology is intended to replace traditional coke ovens, blast furnaces, and basic oxygen furnaces with a direct reduction process. In contrast to other direct reduction technologies, this process would eliminate not only the majority of conventional iron-making processes, but also major aspects of steel-making. Inbath smelting uses coal instead of coke. Eliminating the coke ovens, which are increasingly expensive to replace and operate because of environmental problems, reduces the cost per ton of steel while maintaining existing capacity. With this technology, coal and iron ore are fed into a liquid bath of iron containing a high percentage of carbon. The carbon reduces the iron by removing oxygen from the ore, forming carbon monoxide and molten, elemental iron. Oxygen is injected into the exhaust gases before they leave the smelting vessel. Some of the gases are burned. This process, called post combustion, generates additional heat. This energy is recovered in a production process. The hot, reducing exhaust gases are recycled to a pre-reduction vessel where they react with the incoming ore before it is injected into the bath. In this way, the ore is not only heated, but also a portion of the oxygen content is removed prior to charging the ore into the smelting vessel. Alternatively, the gases could undergo further reactions to produce an even more reducing gas, or it could be recovered as a fuel gas for use elsewhere in the plant. After the inbath smelting, the molten iron can be potentially treated by a continuous refining process for desulfurization and decarbonization. One of the main limitation of the process, to date, is the inability to recycle scrap. 4.3.3 Mini-mill technology

Mini-mills utilize electric arc furnaces to process scrap. They have capacities of approximately 130 ton/hour, about half of the 200 - 300 ton/hour which is typical for a standard BOP furnace. Mini mills are more flexible than many traditional steel plants, and they avoid the environmentally poor coke/iron making steps. However, they are quite energy intensive. Much of the product metal also contains traces of other metal contaminants, which prohibit its use as sheet steel in the automotive industry. Moreover, the electric process produces ionized nitrogen, which can lead to excessive hardening of the steel.

4.3.4 Dry quenching of coke

- Accomplishes significant energy savings by means of recovery of the waste heat (more than 80% of the sensible heat of hot coke, i.e., about 1.3 GJ/t of coke),

- Reduced water pollution, - Better coke quality (very low moisture and better strength).


Dry quenching of coke is done by circulating a non-oxidizing gas over the hot coke in a closed loop. This disposes of the problem of the plant equipment being exposed to corrosive phenolic water and vapor. The heat recovered by the non-oxidizing gas may be utilized in a closed loop for the generation of steam or electric power. 4.3.5 Other technologies

Coke making will see expanded regulatory constraints in the coming years and has always been one of the industry’s more difficult areas, with air emissions and quench water as major problems. Dust generation in the electric arc furnaces (EAF), and its disposal, have also been recognized as a serious problem, with the potential for material recovery. Some of the proposed waste minimization opportunities for the above problems are tabulated in Table 4.6.

Table 4.6. Proposed Waste Minimization Opportunities Perceived need Proposed

solution Status Potential

impact of change

Transfer potential

Pollution control from coke making

Dry quenching of coke

In use in Europe

Eliminate suspect carcinogen particulates, VOC’s etc.

Limited and slow

Tar decanter sludge reuse

Return to oven

Under investigation

Eliminate listed hazardous waste

None

EAF dust reuse Pelletize dust R & D underway

Eliminate hazardous waste

good if successful only within industry

EAF waste acid management, both source reduction and recycling

Recovery of CaF2 as raw material

Proposed probably not implemented

Eliminate waste sludge solids, and purchase of virgin Fluorspar

Limited, based on plant design

Pickling acid management and recovery

New membrane technology; distillation

New product/ process from allied

Need to neutralize and dispose off sludge

Extensive if cost effective

(Source: USEPA, 1992) 4.3.5 Recommendations for pollution prevention and control

Where technically and economically feasible, direct reduction of iron ore for the manufacture of steel is preferred because it does not require coke manufacturing and


because it has fewer environmental impacts. The following pollution prevention measures should be considered to achieve the target levels:

(i) Blast furnace operations

- improve the blast furnace efficiency by using coke for reduction and other fuels for supplementary energy;

- recover thermal energy of the blast furnace off-gas before using it as fuel; - increase fuel efficiency and reduce emissions by improving blast furnace charge

distribution; - improve productivity through screening of the charge and better tap-hole

practices; - take action to reduce dust emissions at furnaces, such as covering iron runners

when tapping the blast furnace, using nitrogen blankets during tapping, using eccentric bottom tapping, and continuously charging of furnaces and ladles;

- use pneumatic transport, enclosed conveyor belts, or self-closing conveyor belts, wind barriers, and other dust suppression measures to reduce the formation of fugitive dust;

- use low NOx burners to reduce NOx emissions from burning fuel in ancillary operations.

(ii) Steel manufacturing

- use dry process for the granulation of slag; - reduce energy requirements by preheating scrap and sinter and utilizing energy

from hot steel products and sinter coolers; - use dry dust collection and removal systems to avoid the generation of

wastewater; - use dry sulfur oxide removal systems (such as carbon absorption or lime spraying

in flue gases). 4.4. Concluding Remarks

Where technically and economically feasible, direct reduction of iron ore for the manufacture of steel is preferred because it does not require coke manufacturing and because it has fewer environmental impacts and reduction of specific energy consumption. The use of advanced air pollution control equipment are essential for better air pollution control. Although sulfur oxides are removed with scrubbers and carbon absorption, use of low sulfur fuels may be more cost effective. The acceptable levels of NOx can be achieved either by using low NOx burners or other combustion modifications.


Various recirculation options for wastewater and solid waste are discussed. Use of tertiary treatment for wastewater may be needed to meet the existing effluent standards. Wastewater treatment systems typically include sedimentation to remove suspended solids, physical/chemical treatment such as pH adjustment to precipitate heavy metals, and filtration. Biological treatment may be required to reduce COD levels. Solid wastes containing heavy metals may have to be stabilized using chemical agents before disposal.


5. CROSS COUNTRY COMPARISON OF THE IRON AND STEEL INDUSTRY

5.1. Introduction

The iron and steel industry is one of the most important industries in the developing countries. It plays a significant role in the industrial sector in the aspects of economics, energy and environment. Although the world steel production has been declining in the recent years, some Asian developing countries are enjoying an increasing trend in steel production. The steel products demand is expected to get higher in Asia due to rapid industrialization and infrastructure development. Therefore, there is a call for formulation and implementation of energy conservation and pollution abatement measures in iron and steel industry so that future steel demand can be met in energy efficient and environmentally friendly manner. Since the iron and steel industry is well defined and is quite a mature sector in the industrialized countries, the advantage of Asian developing countries is that they can learn from the experiences of their predecessors and can adopt suitable technologies for themselves. The process technologies used and the trends of development of iron and steel industries in the developing countries are different from each other due to various inherent differences. This section presents a cross-country study of iron and steel industries in China, India, Philippines and Sri Lanka. Important parameters are compared among the countries which are under study as well as industrialized economies in order to understand the major causes of inefficiency in energy use. Also, the available data on effluent and emission characteristics are compared with the German standards. The potentials of application of energy efficient and pollution abatement technologies are mentioned for each country while taking into consideration the current status of technologies used and the future trends of the industry.

5.2. Overview of the Industry

In this section, comparisons are made in order to understand the relative importance of the iron and steel industries of countries from the national point of view of the economy, share in total energy consumption, and the production trends of steel. 5.2.1 Role in the national economy

In 1992, the Chinese iron and steel industry accounted for 5.4% of the total national industrial output and 3.6% of the gross social output value. In 1989, the Indian iron and steel industry had a share of 7.68% in the total manufacturing economy and about 1% of the gross domestic product.

Cross Country Comparison of the Iron and Steel Industry 57

In 1992, the Philippine iron and steel industry contributed 7.6% in the total industrial sector output and 2.48% of the gross national product. 5.2.2 Share in the total energy consumption

From the energy consumption point of view, the relative importance of the iron and steel industries of China and India are given in Figure 5.1. The iron and steel industry of the Philippines is one of the largest electricity consumers since it employs only electric arc furnaces. In 1992, the electricity consumption accounted for 13.8% of the total industrial electricity consumption and 4.9% of national electricity consumption.

0

5

10

15

20

25

30

35

China India

%

Share in Industrial Sector

Share in National Consumption

Figure 5.1. Energy share of the iron and steel industry in China and India

5.2.3 Trends of production

The production trends of crude steel are presented in Figure 5.2. The World total crude steel production has been declining since 1989. However, the production growth rates of China and India are increasing very rapidly, especially in the recent years. China is enjoying the most rapid growth rate in crude steel production in the World and was the second largest crude steel producer in 1993. In China, the growth rate of pig iron production is higher than that of crude steel production in recent years. However, most of the integrated mills in India prefer to produce the higher valued added steel items resulting in a slowdown of growth in pig iron production. The output of finished steel in the secondary steel sector of India declined by 1.6% in 1991-92 because of the inadequate availability of imported steel scrap and a fall in demand. In India, the steel produced from the integrated mills has the highest growth rate, which was 13.3% more in 1992 as compared to 1991. The Philippines is a steel importing country. In 1986, about 30% of the total demand was met by imported steel. The iron and steel industry of the Philippines produces crude steel mainly from recycled steel scraps and imported scraps by employing electric arc furnaces.


The production depends heavily on the availability of steel scraps and has been decreasing in recent years.

0

10

20

30

40

50

60

70

80

90

1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992

Years

Mill

ion

Tons

ChinaIndia

8.1%

1.57%

World Steel Production

500550600650700750800

1982 1984 1986 1988 1990 1992

Years

Mill

ion

Tons

Philippines' Steel Production

0

0.1

0.2

0.3

0.4

0.5

0.6

1982 1984 1986 1988 1990

Years

Mill

ion

Tons

Figure 5.2. Production trends of crude steel In Sri Lanka, there is only one electric arc furnace which was closed due to the escalated electricity price. The iron and steel industry of Sri Lanka is currently producing rolled steel from imported billets. The production trend of the rolled steel is given in Figure 5.3. The production has been increasing dramatically since 1990. 5.2.3 Mills and Capacities

The trends of increases in total number of iron and steel mills in China and India are shown in Figure 5.4. Along with the significant growth in steel production, the number of Chinese mills is found to be increasing rapidly, reflecting the boom of iron and steel industry of China.


0

10

20

30

40

50

60

70

1960 1970 1980 1990 1992

Years

Thou

sand

Ton

s

Figure 5.3. Production trend of rolled steel in Sri Lanka

17441829

15891478

13931332

16891332

0

500

1000

1500

2000

1978 1980 1982 1984 1986 1988 1990 1992

Years

Num

ber o

f Mill

s

ChinaIndia

Figure 5.4. Trends of mill expansions in China and India

In China, there were 17 mills with the plant capacity of more than 1 million tons of steel per year and 21 mills with the plant capacity of 0.5-0.9 million tons of steel per year in 1992. The average production capacity of steel mills was 0.25 million tons of crude steel per year in 1992. The growth rates in number of mills for different annual capacities are given in Figure 5.5.


Num

ber

of M

ills

1

10

100

1000

10000

1986 1988 1990 1992

Total > 1 Mton 0.5-0.9 Mton

2.27%

2.95%

21.65%

Figure 5.5. Growth in number of mills by different annual capacities in China

The steel mills with the annual plant capacity of 0.5-0.9 million tons are growing very rapidly in China. In India, there are 7 integrated steel plants with the total capacity of 17.3 million tons per year. The total installed capacity in 1993 was 25.4 million tons of crude steel and public sector accounted for 63% of the total installed capacity. The secondary steel sector (small and medium mills which use electric arc furnaces and induction furnaces) has been growing rapidly since 1973 and has resulted in an increase in the electricity use in the sector. As a major policy change, the secondary steel mills which use sponge iron instead of scraps are expected to grow more rapidly in the future. In the Philippines, there are about 60 local firms in the iron and steel industry. In 1989, there were 12 companies producing steel with electric arc furnaces having a total capacity of 718,000 tons of crude steel per year. Some existing mills recently expanded their production capacities to meet the increasing steel demand of the country. In Sri Lanka, there is only one public mill with an installed rolling capacity of 96,000 tons per year and four private mills, each with a rolling capacity of about 8,000 tons per year. The share of private sector in total steel production has increased from 4.55% in 1990 to 17% in 1992. The state-owned mill is expected to be privatized soon due to the policy of privatization of state industries. A few small mills with electric arc furnaces have been commissioned very recently but the capacity and production data are not available. The capacity utilization factors (crude steel) in the selected countries are shown in Figure 5.6.


0

20

40

60

80

100

China India Philippines

%

Figure 5.6. Capacity utilization factors (crude steel) in 1992

In Sri Lanka, the capacity utilization factor of rolling mills improved from 52% in 1985 to 55% in 1995, but that of wire products section dropped from 35 to 27% over the same period. 5.3. Parameters Affecting Energy Efficiency

The specific energy consumption of iron and steel industries of the four countries is shown in Figure 5.7. It mainly depends on the following:

- Raw material mix - Level of waste heat recovery - Steel-making process mix - Share of continuous casting in total production, and - Product mix.

In this section, some parameters affecting the specific energy consumption of the iron and steel industry are compared. The trends of evolution in the specific energy consumption of iron and steel production are compared in Figure 5.8 for some countries. The specific energy consumption has been decreasing in both China and India, and this reduction has been more rapid in India. However the consumption is still much higher than those of industrialized countries. Concerning the raw materials, the level of waste steel utilization in developing countries is lower than that of industrialized economies. For instance, the waste steel utilization was 28.03% in China in 1988. However, the waste steel ratios were 31.6% in Japan, 48.2% in USA and 44.8% in UK in 1983.


0

5

10

15

20

25

30

35

40

China India Japan US

GJ/

ton

of S

teel

Figure 5.7 Specific energy consumption of integrated iron and steel industry

10

15

20

25

30

35

40

45

50

1983 1984 1985 1986 1987 1988 1989 1990 1991 1992

Years

GJ/

tons

of S

teel China

IndiaJapanUSA

Figure 5.8. Trends of specific energy consumption in selected countries

In developing countries, iron ore used is of lower grade and the coal has higher ash content as compared with those used in industrialized countries. For instance, the grade of iron ore used in China is 52.17% and that in Japan is 59%. The ash content of coal used in China is 13-14% and that in Japan is about 10%. 5.3.1 Steel-making process mix

The total production of crude steel and shares of different steel-making processes are compared in Table 5.1.


Table 5.1. Total crude steel production and shares of steel-making processes in

1992

Country BOF (%)

EAF (%)

OHF (%)

Total production

(Million tons) China 60.9 21.8 17.3 80.93India 45.5 28.2 26.3 16.22Philippines * 0 100 0 0.47Japan 68.4 31.6 0 98.10USA 62.9 37.1 0 83.20

* 1991 data The level of BOF employment in China is found to be comparable to the industrialized countries. The large share of OHF-steel in both China and India is one of the major causes of higher specific energy consumption levels. The evolution of the share of OHF steel in China and India can be seen in Figure 5.9.

5.3.2 Iron to steel ratio

The iron to steel ratio in steel making processes is compared for different countries in Figure 5.10. The higher iron to steel ratio leads to higher specific energy consumption. This ratio is found to be quite high for China.

0

10

20

30

40

50

60

1982 1985 1986 1987 1988 1989 1990 1991 1992

Years

% o

f Tot

al P

rodu

ctio

n

IndiaChina

Figure 5.9. Evolution of the share of OHF steel in China and India


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1


Rat

io o

f Iro

n/S

teel

Figure 5.10. Iron to Steel Ratio of Selected Countries in 1988

5.3.3 Share of continuous casting

The continuous casting process is a significant energy saving technique in iron and steel industry. However, the share of continuous casting is still very low in developing countries, as can be seen in Figure 5.11.

22.412

94

67.1

0

20

40

60

80

100


% o

f Tot

al P

rodu

ctio

n

Figure 5.11. Share of continuous casting in selected countries in 1990

However, the dissemination rate of continuous casting in China has been accelerated since 1989. The trends of continuous casting ratio for some countries are given in Figure 5.12.


% o

f Tot

al P

rodu

ctio

n

0

10

20

30

40

50

60

70

80

90

100

1985 1986 1987 1988 1989 1990 1991 1992

ChinaJapanUSWorld

Figure 5.12. Share of continuous-cast steel

5.3.4 Energy consumption at sub-processes

The average specific energy consumptions of major processes at the integrated plants in China and India are compared with those of developed countries in Figure 5.13.

0

5

10

15

20

25

Coke-making Sintering Iron-making Steel-making

GJ/

ton

of S

teel

ChinaIndiaDeveloped Countries

Figure 5.13. Specific energy at sub-processes

The higher energy consumption for the steel making process in India can be explained by the greater share of OHFs. However, the inefficiencies of coking and iron making


processes are due to the low quality of coal, limited recovery of waste heat and outdated technologies. Sponge iron production through efficient direct reduction process has been also done in India but the share of direct reduction process is not available. The share of BOF-steel is expected to increase in both China and India along with the conversion of inefficient OHF to BOF. The specific energy consumption of BOF is given in Figure 5.14 for China, India and the developed countries. The specific energy consumption of Indian BOF is as much as 3 times that of developed countries.

0.79

1.77

0.56

0

0.4

0.8

1.2

1.6

2

China India DevelopedCountries

GJ/

ton

of S

teel

Figure 5.14. Specific energy consumption of BOF

5.3.5 Capacity of equipment

Although the total crude steel production of China is as much as five times that of India, the total number of mills in China is lower than that in India. Therefore, the average capacity of Chinese mills can be said to be higher than Indian plants. However, the capacities of equipment used in China are still much lower than those of Japanese mills. A comparison is given in Figure 5.15. The average capacity of Chinese blast furnaces is 45 times less than that of Japanese mills. In fact, the higher the equipment capacity, the more economical it is to recover the waste heat. 5.3.6 Awareness on energy conservation

Among the four countries under study, China has the highest awareness of energy conservation measures in iron and steel industry. As an important industry in manufacturing sector, energy conservation measures have been taking place in Chinese iron and steel industry since 1978. Therefore, the energy consumption of Chinese iron and steel industry increased by only 39.2% during the period between 1980 and 1990 while the output of steel products increased by 80.5%. Nearly all modernized energy saving


technologies can be seen in the Chinese iron and steel industry but the dissemination rate is very low in comparison with developed countries.

Thou

sand

tons

/yr

0

500

1000

1500

2000

2500

Blast furnace Converter EAF Coke oven C. Caster

ChinaJapan

Figure 5.15. Average capacity of equipment in China and Japan

More than 780 energy saving projects have been implemented in China since 1978 and most of them are continuous casting, coke dry quenching, top pressure recovery turbine and converter gas recovery. The cumulative energy savings from the measures undertaken in China are shown in Figure 5.16.

Mill

ion

TOE

0

5

10

15

20

25

1978 1982 1986 1990 1992

Phase 1

Phase 2

Phase 3

Figure 5.16. Cumulative energy savings in China

From 1978 to 1992, the specific energy consumption of iron and steel industry was reduced by 37.5% in China. During the first period (1978-1982), the important measures that got implemented were encouraging the energy conservation activities, enhancing the management of energy utilization, reducing the energy waste, etc. In the second period (1982-1986), energy efficient technologies such as gas recovery of converter, continuous


casting, waste heat recovery were introduced and laws and regulations on energy conservation were enacted. From Figure 5.16, it can be seen that energy saving rate became slow in the third phase (1986-1992). Since the specific energy consumption of Chinese iron and steel industry is still higher than that of developed countries, additional efforts are necessary to speed up the energy saving rate further. In India, the specific energy consumption of iron and steel industry has been decreasing significantly since 1988; however, it is still much higher than that of developed countries and even that of China. The energy conservation measures taken are mostly of small and medium scales such as insulation improvements, installation of recuperates and regenerative ceramic burners, combustion improvements, efficient lighting, oxygen enrichment, control of electrical equipment, etc. It is necessary to focus on process technologies and waste heat recovery to achieve further reduction in specific energy consumption. The awareness of energy conservation in the Philippines and Sri Lanka is limited since the iron and steel industries of these countries do not play very important roles in national economies. Most of the mills in these countries do not have measuring devices on equipment used and the processes are run without controls. 5.4. Parameters Affecting Pollution Abatement Measures

While the energy saving applications in the industry end up with the cost savings in the manufacturing process; the installation, operation and maintenance of pollution abatement devices pay no incentives, perhaps entail additional cost for the industry except for a few cases where some valuable raw materials are recovered. However, strict government policies and public awareness due to growing industrialization in this region merely force the industrialist to operate some sort of pollution abatement programs. The use of obsolete machinery and technologies generally in use in this region further strengthen the already deteriorated environmental issues. The type and quantity of pollutants produced vary from industry to industry depending on the process used. 5.4.1 Causes of pollution problems

As is generally the case, the pollution abatement measures in these countries are at preliminary levels. Following are commonly reported reasons for the pollution problems in these countries:

- poor quality of raw materials and fuel - obsolete technology and machinery in use - poor implementation of the environmental regulations - large number of small industries - feeling that it is an extra expenditure without pay-back


5.4.4 Current water pollution control strategies

Among the four countries under study, China and India pay more attention on pollution control than Philippines and Sri Lanka. In China during a twelve-year period starting from 1980, following were achieved:

- Fresh water consumption reduced to 52 ton/ton of steel produced from 90 ton/ton steel;

- Wastewater re-use rate increased to 78% from 60%; - Treatment rate of wastewater increased to 94% from 12%.

In India during 1988-1992:

- Fresh water consumption reduced to 12 ton/ton of steel produced from 50 ton/ton steel;

- Effluent qualities are well within the local regulatory standards.

In the Philippines and Sri Lanka: - Many wastewater streams discharged without treatment; - Lack of data regarding effluent quality, water consumption, wastewater treatment,

etc. 5.4.3 Current air pollution control strategies

Iron and steel industry generate considerable amount of air pollutants. Though in the recent years a number of measures are being taken to control these pollutants, they are at their primary levels. In China, some measures are being taken to abate dust and smog discharge from the process. Serious efforts were made to recover the waste gases from coke ovens and blast furnaces but less attention was paid to recover gas from converters. Also during the period of 1980 to 1992 the amount of dust discharged reduced to 11 kg/ton of steel produced from 14 kg/ton steel and treatment rate of waste gas increased to 90% from 25%. In India while wet scrubbers and cyclones (number of units installed: 415 and 300, respectively) play a major role in air pollution control, modern air pollution control equipment such as bag filters and electrostatic precipitators (number of units installed: 118 and 87, respectively) are widely used in the integrated steel plants. Such usage of air pollution control equipment led to the reduction of dust emission to 300 mg/m3 from 600 mg/m3 during the period of 1988 to 1992. 5.4.4 Current solid waste control strategies

Generally in all these countries solid wastes generated from the process itself and secondary wastes arise from pollution control measures such as dust collection equipment and wastewater treatment, are dumped at landfill sites without any pretreatment. However in


metallurgy sector of China, some efforts are underway to recover the iron content in mud and usage of metallurgical slags. In India, utilization of blast furnace slag instead of concrete in heavy duty road construction and recycling BOF slag to blast furnace are under consideration. 5.4.5 Comparison of effluent and emission characteristics

In general, the information provided in the country reports are quite diverse. As seen from the Indian and Chinese data, the effluent and emission standards have improved significantly. However the data provided are on different basis. As some of them are given in per ton production basis whereas others in ambient standards, it makes the comparison impossible in some cases. For the purpose of comparison it is preferable to have the amount of pollutant released per ton of product than in ambient standards. It is mainly because the allowable discharge of pollutants to the surroundings in different countries depends on the geographic location, climatic condition and overall intensity of pollutants released from all other sources. A comparison of fresh water consumption and quantity and characteristics of wastewater with German standards is made in Table 5.2. Even though a number of parameters is tabulated, most of them cannot be compared with each other due to the limitation of available data. It could be noted that the fresh water consumption in India is four to five fold less than that of China which means lesser amount of wastewater is produced in Indian industries. However, the water consumption in China is still less than that of USA (more than 100 ton/ton of steel produced). Also, according to the data, effluent characteristics of Indian steel industries meet their local regulatory standards. As can be seen in Table 5.2, no such data are available for the Philippines and Sri Lanka, may be due to the minor share of these industries in their national economies. In Table 5.3 the process specific German standards are provided. However, as no process specific data are available in the country reports, no comparison has been made. A similar comparison for air emissions is shown in Table 5.4. As said earlier, a comparison was not possible in most of the cases due to the limitations in the availability of data and the different basis of the values provided. In case of Indian iron and steel industry, the only data available are on dust emission. Even though the dust emission in Indian iron and steel industry meets local regulatory standard (350 mg/m3) it is very much higher than the German regulatory standards (30 mg/m3). In China, about 80% emission discharge meets its regulatory standards. Here also no data are available from the Philippines and Sri Lanka.

Table 5.2. Quantity and characteristics of wastewater released

Parameters Germany * China India *** Philippines

Sri Lanka

Water consumption (ton/ton steel produced)

51.7 10-12 - -


Wastewater discharged (ton/ton steel produced)

35 - -

pH - - Suspended solids (mg/l) 80

(100) - -

Settleable solids (ml/l) 0.5 - - DS (mg/l) - - BOD5 (mg/l) - - COD (mg/l) 100 - - Oil and Grease (mg/l) 1.25-2 (10) - - Total N (mg/l) - - Total P (mg/l) - - Phenol (mg/l) 0.25-1.0

(1.0) - -

Cyanide (mg/l) 0.09 - - Heavy metals (mg/l) - Pb - Zn

0.5 4.0

- -

Wastewater reuse rate (%)

78.27 - -

Treatment rate of wastewater (%)

94.34 - -

Hydro carbons (mg/l) ** 10 - - * The German regulatory standard is based on the 2-hour composite sampling ** Hydrocarbons only from mineral oils *** The values in the brackets are the Indian regulatory standards Note: Cr,Ni,Cu,As, tin, fluoride and cyanide standards should be decided specifically for

each and every process (from German standards).

Table 5.3. The process specific German standards

Process Settleable solids (ml/l)

COD (mg/l) Pb (mg/l)

Foundry 0.8 200 - Tube mill - 200 - Sheet mill - 200 - Coating with Pb - - 2.0


Table 5.4. Quantity and Characteristics of Air Pollutants Released

Parameters Germany China India ** Philippines Sri Lanka Dust discharged (TSP) (mg/m3) 30 11.0* 250 (350) - - SO2 (mg/m3) 100 - - NOx (mg/m3) 500 - - CO (mg/m3) 100 - - Organics (mg/m3) - - Heavy metals (mg/m3) - - Treatment rate of waste gas (%) 89.9 - - Rate of treated waste gas discharged which meet standards (%)

78.36 - -

* in kg/ton steel produced; ** The values in the brackets are the Indian regulatory standards 5.5. Potential for Energy Efficiency Improvements

5.5.1 Measures on the structure of the industry

Since the iron and steel industry is expected to grow, the future expansion should be well planned in order to achieve better energy efficiency. The level of waste heat recovery plays a significant role in specific energy consumption of the iron and steel industry because the temperatures of the processes involved are quite high. The economics of waste heat recovery is scale-sensitive. Therefore, the larger mills can improve energy efficiencies in financially feasible manner. The restriction of the growth of inefficient small mills is therefore necessary for all countries, especially in China, where the number of mills is increasing very rapidly. Although the larger the mill, the lesser is the specific energy consumption; the optimum mill capacities will depend on the social, geographical and economic conditions of a particular country. Therefore, the optimum level of mill capacity should be estimated on the basis of various considerations to plan the future expansion of the industry. Harnessing of new and energy efficient technologies in new steel plants is also important for assuring better energy use in iron and steel industry. 5.5.2 Measures on raw materials and products

The higher ratio of waste steel in raw materials will lead not only to lower specific energy consumption but also assist in the preservation of the resources. The lower quality of iron ore and coal used in China and India is one of the main causes of the higher energy consumption. The pre-treatment of raw materials should be studied for reducing the overall specific energy consumption.


As far as the products are concerned, the reduction of foundry pig iron production in China can lower the energy consumption of the iron and steel industry since this needs much greater energy than that of pig iron for steel-making. 5.5.3 Potential of energy conservation measures

The potential of major energy conservation measures is summarized in Table 5.5 on the basis of the status of technologies currently in use and the future expansion of the industry.

Table 5.5. Potential of Energy Conservation Measures #

Energy Conservation Measures China India Philippines

Sri Lanka

Short Term Measures - Management practices - Insulation Improvement - Increase in EAF capacity - Combustion air Control

** ** *** **

*** *** **** ***

**** **** **** ****

**** **** **** ****

Medium Term Measures - Substitution of OHF with BOF - Coal injection into blast furnace - Coal moisture control (CMC) - Continuous casting - External desulfurization - Recovery of slab sensible heat - Introduction of modernized blast furnace - Continuous scrap charging - Oxygen enrichment of combustion air - Scrap preheating - Introduction of ultra high power EAF - Waste heat recovery in sinter cooler - Coke dry quenching - Waste heat recovery in blast furnace - Top Pressure recovery turbine (TRT) - BOF gas recovery - Direct rolling - Combine cycle power generation

*** *** **1 *** **** *** **** *** *** *** *** ***

****2 ***4 ***5 ***6 ****7 ****

**** **** **** **** **** *** **** *** *** **** **** **** ****3 **** **** **** **** ****

- - -

**** -

*** -

*** **

**** ****

- - - - -

**** -

- - -

**** -

*** -

*** **

**** *** - - - - -

**** -

Long Term Measures - Direct steel-making - Computerization

**** ****8

**** ****

- ****

- ****

# Note: For each energy conservation measure, the relative scope of application is shown by the number of asterisks. For instance, the replacement of OHF by BOF has a higher


scope in India since about 26% of Indian steel is produced by OHF but only 17% in China. However, this measure has no scope in the Philippines and Sri Lanka where only EAFs are employed.

1 CMC technology has been in use in China for about ten years 2 4% of mills have been using coke dry quenching (CDQ) 3 only one relatively new plant is using CDQ technique 4 about 20% of the blast furnaces have been equipped with waste heat recovery

devices 5 only 20% of blast furnaces whose volume is over 1000 m3 have been installed with

TRT 6 about 50% of the converters, each with a volume of 15 tons, have been equipped

with recovery devices 7 dissemination rate is about 5-6% at present 8 limited number of Chinese mills have installed computer-control systems in

processes 5.6. Potential for Pollution Abatement

As this environmentally polluting industry is growing rapidly in the region, any future expansion should be well planned to abate pollution load to the environment. As seen earlier, the pollution abatement measures in these countries are in their preliminary stages. So as a first step, one must record the pollution loads and water consumption. The source reduction and waste minimization measures rather than end of pipe treatment not only lead to cost saving in waste treatment but also save the depleting natural resources. Recycling of the waste from different processes, particularly the wastewater, should be a serious concern. Larger the mill, lesser is the specific treatment cost both in terms of capital as well as operation and maintenance costs. So it is important to have restriction on the growth of the small mills, especially in China. Although the larger the mill, the lesser is the specific pollution abatement cost, the optimum capacities of mills would depend on social, geographic and economic conditions of a particular country. Therefore, the optimum level of mill capacity should be estimated on the basis of various considerations to plan the future expansion of the industry. Though the usage of good quality raw material will lead to reduction of pollution load, potentials for such measures are very limited due to the depleting trend in the natural resources. However, improved procedure for inspection and classification of scraps will lead to cleaner scrap in the electric arc furnace charging mix, subsequently a reduction in the volume and toxicity of the dust generated from the furnace operation. The potentials of important pollution abatement options based on the available technologies are summarized in Table 5.6.


Table 5.6. Potentials for Pollution Abatement Measures #

Pollution Abatement Measures China

India Philippines Sri Lanka

Short Term Measures - Management practices - Good house keeping - Operating at optimized parameters - Full capacity utilization - Prevention of leakage, spills, overflows

etc. - Resource recovery and recycling - Strict implementation of environmental

regulations

*** *** *** *** *** *** ***

**** *** *** *** *** *** ***

**** *** *** *** *** *** ***

**** *** *** *** *** *** ***

Medium Term Measures - Coke dry quenching - Substitution of OHF with BOF and EAF - Direct reduction - Efficient air pollution control equipment - Advance wastewater treatment

*** *** **** *** ***

**** **** **** *** ***

- - -

*** ***

- - -

*** ***

Long Term Measures - Direct steel-making - Process automation and computerization

**** ****8

**** ****

- ****

- ****

# Note: Number of asterisks implies the relative scope of application for each pollution abatement measure

5.7. Conclusion

The potential for energy saving and pollution abatement in iron and steel industry is quite high in Asian developing countries since the industry is characterized by outdated technologies. Even in highly advanced countries like economies in Europe, the energy saving potential in iron and steel industries was estimated to be 20-30%. The most significant energy saving could arise from process changes such as replacement of OHF with BOF, coal injection, coke dry quenching, continuous casting and direct rolling. The major energy saving opportunities offered in the iron and steel industries of the countries under study are heat recovery from the various waste streams, top gas pressure turbine, BOF gas recovery, scrap preheating and continuous scrap charging. The low cost measures including proper housekeeping could be good initiatives to boost both the energy conservation and pollution abatement in countries like the Philippines and Sri Lanka.


For the pollution abatement measures, source reduction followed by waste minimization should be the priority consideration than the end of pipe treatment methods. Such measures will lead to both cost saving as well as resources saving. To achieve this, process changes such as coke dry quenching, substitution of OHF with BOF and EAF, and direct reduction are essential. Pollution abatement with potential for energy savings could be materialized through a greater awareness about energy conservation, pollution abatement and wider acceptance of the new and energy efficient and environmentally sound technologies. Therefore, encouragement and cooperation from the public institutions and setting of dissemination strategies for energy efficient and environmentally sound technologies are the actions that are necessary for improving energy efficiency and pollution abatement of the iron and steel industry.

Profile of the Iron and Steel Industry in Selected Asian Countries 77

6. PROFILE OF THE IRON & STEEL INDUSTRY IN SELECTED ASIAN COUNTRIES

This section evaluates the current status and technological trajectory of the iron and steel industry in four Asian countries, namely China, India, the Philippines and Sri Lanka. 6.1 Country Report: China

6.1.1 Introduction

This section intends to lay-out the historical and existing conditions in the iron and steel industry of China with regard to the technological development of more energy efficient and environmentally-sound industrial technologies. Being a highly energy-intensive and polluting industry, the diffusion of clean and efficient technologies into the industry is one of the major considerations in today’s global environmental protection agenda. A closer look into China’s situation would have great implications insofar as the country’s future economic, energy, and environmental policies are concerned. The annual output of steel in China has increased rapidly (Table 6.1.1 & Figure 6.1.1), with an average annual growth rate of 8% during the period 1988-1990. In 1993, the steel output of China reached more than 88 million tons (Mt), ranking second in the world after Japan.

Table 6.1.1 Output of steel in China and in other countries (Mt)

Year World China USSR Japan Germany

UK France

USA Italy

1951 210.70 0.90 27.33 6.50 13.40 15.90 8.90 95.00 - 1955 269.20 2.85 45.27 9.40 21.33 20.10 12.59 106.17 - 1974 710.11 21.12 136.00 117.50 53.20 22.40 27.00 132.40 - 1980 716.30 37.12 147.93 111.40 43.84 11.28 23.17 101.46 26.5

0 1985 717.00 46.79 155.00 105.28 40.50 15.72 18.81 80.07 23.9

0 1987 734.00 56.28 161.90 98.51 36.25 17.16 17.53 80.88 22.8

5 1989 783.50 61.32 160.70 107.90 41.00 18.00 19.00 88.90 25.1

0 1990 769.60 66.30 154.41 110.34 38.34 17.90 19.01 89.73 25.4

7 1991 732.80 71.00 133.64 109.66 38.90 16.49 18.41 79.20 25.0

8 1992 714.00 80.93 111.20 98.10 - 16.10 18.00 83.20 24.8

0 Source: Statistics of the iron & steel industry of China, 1993 Energy office, MMI, 1990


News of energy policy research, No. 12, 1992 Note: USSR & Germany in this table, (as well as in all the following tables) refer to the

former Soviet Union and the former West Germany.

0

2000

4000

6000

8000

10000

1980 1982 1985 1986 1987 1988 1989 1990 1991 1992

year

Prod

uctio

n (1

0,00

0t)

pig ironcrude steelrolled steel

Figure 6.1.1 Output of major products in the iron & steel industry of China

6.1.2 Technological trajectory of China’s iron & steel industry

6.1.2.1 Capacity and productivity of the iron & steel industry of China

Table 6.1.2 outlines some characteristics of the modern iron & steel industry of China.

Table 6.1.2 Characteristics of China’s iron & steel industry sector

Item Unit 1980 1986 1988 1990 1992 Number of plants - 1332 1393 1478 1589 1744 Annual steel output (0.5-0.9 Mt)

- 2 6 8 12 21

Annual steel output (>1 Mt) - 12 14 14 16 17 Number of personnel 106 pers 2.441 2.808 3.048 3.153 3.283 Gross output value* 109 yuan 342.2 489.2 551.3 1310 1589.1 Major plants 109 yuan 235.2 324.8 351.6 821.7 965.4 Share of the total % 68.7 66.4 63.8 62.7 60.8 Net output value** 109 yuan 105.4 199.8 276.8 317.9 507.3 Major plants 109 yuan 79.9 135.5 186.0 211.8 309.5 Share of the total % 75.8 67.8 67.2 66.6 61.0 Net fixed assets 109yuan - 502.8 621.4 774.9 1113.4 Fixed assets investment 109yuan 46.31 92.32 158.9 127.5 217.9

Item Unit 1980 1986 1988 1990 1992 Production capacity: Crude steel Mt 39.26 55.98 62.89 71.21 85.98 Continuous casting steel Mt 2.95 8.21 9.30 16.86 24.16


Finished rolled steel Mt 30.00 51.24 59.70 73.38 83.70 Pig iron Mt 39.72 51.95 57.00 65.31 78.14 Output of major products: Crude steel Mt 37.12 52.21 59.43 66.35 80.93 Finished rolled steel Mt 27.16 40.58 46.89 51.53 66.94 Pig iron Mt 38.02 50.64 57.04 62.37 75.89 Total import & export: 109 US$ 26.5 80.95 62.50 50.17 82.46 of which: export 109US$ 2.5 5.60 14.76 20.10 29.29 import 109 US$ 24 75.35 47.74 30.06 53.17

Source: The Iron & Steel Industry Yearbook of China, 1993 Note: * the values for the years 1980s are calculated at 1980 constant prices, and

those for 1990s are calculated at 1990 constant prices; ** calculated at current prices and by allocation method. The three main indices reflecting the technical level of a country’s iron and steel industry are the proportions of major product outputs classified by the smelting process, the ratio of iron to steel, and the continuous casting ratio. The production data during the 1980-1992 period shows that a considerable increase in the production capacity of continuous casting steel has been realized year by year. This could be attributed to various improvements in the iron & steel sector during the period. Table 6.1.3 shows the development of converter and electric arc furnaces vis-à-vis open hearth furnaces in terms of production and output ratios. Along with the increasing trend in production outputs from converter and electric arc furnaces is the decreasing production output from open hearth furnaces.

Table 6.1.3 Technical data from China’s iron & steel industry

Total Open Furnace Converter Electric furnace Year Output

(Mt) Output

(Mt) % to Total

Output (Mt)

% to Total

Output (Mt)

% to Total

1980 37.10 11.89 32.0 18.10 48.8 7.11 19.2 1985 46.75 12.30 26.3 24.37 52.1 10.08 21.6 1986 52.15 12.36 23.7 29.22 56.0 10.57 20.2 1987 56.22 12.78 22.7 31.96 56.8 11.48 20.4 1988 59.35 13.04 22.0 34.24 57.6 12.07 20.3 1989 61.50 13.13 21.3 35.62 57.8 12.75 20.7 1990 66.32 13.16 19.8 39.14 58.9 14.02 21.1 1991 70.89 13.09 18.4 42.80 60.4 15.00 21.2 1992 80.78 13.99 17.3 49.16 60.9 17.63 21.8

Source: Statistics of the Iron & Steel Industry of China, 1993


The technical level of China’s iron & steel industry, however, still lags behind that of the internationally advanced levels, and this gap is considerably large. For instance, China’s ratio of iron to steel in 1992 was 0.94, as compared to most of the developed countries’ level of 0.6-0.8 in the 1980s. The continuous casting ratio in China in 1993 was only 34%, which is comparable only to the 1980 level in the developed countries (Table 6.1.4). Moreover, the proportion of steel by open hearth furnace production in China was still as high as 17% in 1992 (Table 6.1.5), while almost all the open-hearth furnaces have already been eliminated in the developed countries. 6.1.2.2 Product mix, process mix and equipment used

As far as plant mix is concerned, China’s iron & steel industry is characterized by its large number of small scale plants. In 1992, the total number of plants totaled 1,744, while only 17 plants had an average annual output of more than 1 Mt (million tonnes) and 21 plants had an average annual output of 0.5-0.99 Mt. This shows that most of the plants have very low outputs. All in all, the average production scale was only 0.25 Mt/yr-plant in China's iron & steel industry. By the end of 1992, the total weight of the production devices reached 8.96 Mt, including 1128 sets of blast furnaces (120,800 m3), 71 sets of open-hearth furnaces (120,000 tons), 1567 sets of electric arc furnaces (7,225 tons), 217 sets of converters (5,409 tons), and 2122 sets of rollers. The industry devices are characterized by two properties:

- A small average scale due to a large number of equipment: Only 32 blast furnaces had an average volume of more than 1,000 m3 and the whole sector had an average volume per set of only 107 m3. Only 10 electric arc furnaces had individual capacities of more than 50 tons while the average capacity per set for the whole sector was only 4.6 tons.

- Many devices use outdated technologies: From a 1991 survey, 75-80% of the devices

employed outdated technologies compared with the advanced levels of the world. Sector-wise, the proportions were 80.8% for iron-making, 81% for steel-making, 73% for continuous casting, and 75% for rolling.


Table 6.1.4 Comparison of production ratios between China and other countries

Country

1980 1985 1986 1987 1988 1989 1990 1991 1992

A B A B A B A B A B A B A B A B A B China 1.020 6.2 0.940 10.8 0.970 11.9 0.98 12.9 0.96 14.7 0.94 16.3 0.94 22.4 0.95 26.5 0.94 30.0USSR 0.725 10.7 0.718 13.3 0.708 15.0 0.706 0.695 16.1 0.702 17.3 17.9 17.1USA 0.614 20.3 0.572 44.4 0.538 55.2 0.545 0.558 60.9 0.573 64.8 67.1 78.9Japan 0.781 59.5 0.765 91.1 0.760 92.7 0.745 0.750 93.0 0.743 93.5 93.9 95.4Germany

0.773 46.0 0.779 79.5 0.781 84.6 0.787 0.791 88.5 0.799 89.8 91.3 92.0

France 0.827 41.3 0.827 80.6 0.791 90.0 0.767 0.778 94.0 0.802 94.2 93.1 95.2UK 0.569 27.1 0.665 54.8 0.661 60.5 0.694 0.617 70.5 0.681 80.2 83.6 87.0Italy 0.461 49.9 0.507 78.6 0.519 84.1 0.497 0.481 93.9 0.468 94.1 94.8 96.1India 0.894 0.824 0.862 0.834 0.825 - Brazil 33.2 43.7 46.1 49.0 53.9 58.5 58.0Korea - 63.6 71.7 88.3 94.1 96.1 96.8Sweden 49.0 80.6 81.8 83.0 82.3 85.8 85.8World 29.9 49.7 52.4 58.8 61.2 64.1 -

Source: Energy Office, MMI, 1990 Steel, Vol. 26 to 28 A - Iron/steel ratio B - Continuous casting ratio


Table 6.1.5 Steel production through the smelting process in different countries

Smelting process Open-hearth steel

Converter steel Electric steel Total

Country Year Output (Mt)

% of total

Output (Mt)

% of total

Output (Mt)

% of total

(Mt)

China 1988 13.04 22.0 12.07 20.3 34.24 57.6 59.35 1992 13.99 17.3 17.63 60.4 49.16 21.8 80.78

USSR 1988 80.359 49.3 60.473 37.1 22.168 13.6 163.00 1992 49.00 44.1 38.90 35.0 23.20 20.9 111.10

USA 1988 4.642 5.2 52.57 58.4 32.878 36.5 90.09 1992 0.0 0 52.282 62.9 30.817 37.1 83.099

Japan 1988 0.0 0 74.248 70.3 31.343 29.7 105.681 1992 0.0 0 67.144 68.4 30.98 31.8 98.124

Germany 1988 0.0 0 33.938 82.7 7.085 17.3 41.023 1992 0.548 1.3 30.612 77.1 8.581 21.6 39.741

France 1988 0.0 0 14.083 73.7 5.023 26.3 19.106 1992 0.0 0 12.551 69.9 5.41 30.1 17.961

Italy 1988 0.0 0 10.359 43.8 13.31 56.2 13.669 1992 0.0 0 10.164 40.8 14.74 59.2 24.904

UK 1988 0.0 0 14.008 73.9 4.942 26.1 18.95 1992 0.0 0 12.042 75.3 3.959 24.7 16.001

Korea 1988 0.0 0 - 68.4 - 31.6 - 1992 0.0 0 19.587 69.8 8.467 30.2 28.054

Source: Energy Office, MMI, 1990 6.1.2.3 Role of the iron & steel industry in the economic development of China

The iron & steel industry has been one of the key industrial sectors in China, playing an important role in the national economic system. As shown in Table 6.1.6, the output value of the industry accounts for more than 5% of the total output value of the national industry or more than 3% of the gross social output value.

Table 6.1.6 The role of China’s iron & steel industry in the national economy

Year Gross industrial

product (A) 109 Yuan)

Gross national product (B) (109 Yuan)

Iron & steel output value (C)

(109 Yuan)

% of C to A

% of C to

B

1980 5154 8534 267.1 5.2 3.1 1985 9716 16582 552.1 5.7 3.3 1987 13813 23034 776.3 5.6 3.4 1989 22017 34519 1121.5 5.1 3.2 1991 28225 44142 1435.6 5.1 3.3 1992 36802 54825 1999.5 5.4 3.6 Source: The Iron & Steel Industry Yearbook of China, 1993


Note: Values are in current prices. 6.1.3 Evolution of energy efficiency in the iron & steel industry of China

The iron & steel industry of the country is a major energy-intensive sector which accounts for about 10% of the total national energy consumption (Table 6.1.7).

Table 6.1.7 Energy consumption of the iron & steel industry of China

Year 1980 1985 1987 1989 1991 1992 National total (Mtoe) 401.87 511.20 577.53 646.20 691.87 726.00Iron & steel industry (Mtoe) 47.27 51.87 53.40 61.07 69.07 71.80 % of industry to national total 11.76 10.15 9.24 9.44 9.98 9.89

Source: The Iron & Steel Industry Yearbook of China, 1991, 1993 6.1.3.1 Breakdown of energy consumption

The main fuels consumed by the industry are coal (including coking-coal and fuel-coal), electricity, oil and natural gas. Their breakdown is shown in Table 6.1.8. It is worth noting that the coal-oriented energy resource structure is considered fit for China’s conditions and will not vary a lot in the near future.

Table 6.1.8 Constitution of energy consumption in the iron & steel industry of China

Year 1986 1988 1990 1991 1992 Total energy consumption (Mtoe) 56.03 60.43 65.81 69.03 71.80 Coal (Mt) 70.87 75.47 80.69 85.58 88.42 % to Total Fuels Consumed 70.7 70.0 68.8 69.6 69.2 of which: Coke coal (Mt) 49.29 51.27 55.32 59.14 61.10 Fuel coal (Mt) 21.58 24.20 25.37 26.44 27.32 Coke (Mt) 36.83 40.94 46.24 51.29 52.37 Electricity (TWh) 43.29 49.48 57.97 59.88 66.49 % to Total Fuels Consumed 21.0 22.1 23.7 23.4 24.2 Heavy oil (Mt) 4.13 4.32 4.49 4.41 4.68 % to Total Fuels Consumed 6.9 6.8 6.5 6.1 6.2 Natural gas (106 m3) 733 796 742 717 350 % to Total Fuels Consumed 1.1 1.2 1.0 1.0 0.4

Source: Statistics of the Iron & Steel Industry of China, 1993 6.1.3.3 Energy efficiency and specific energy consumption

As shown in Table 6.1.9, the specific energy consumption per ton of steel in the iron & steel industry of China has decreased from 1.36 toe/t-steel in 1980 to 1.054 toe/t-steel in 1992 with a drop of 22.8%. This has been made possible through efforts on technical innovation and enhancement of energy management in the industry. Compared with the


energy consumption per ton of crude steel (Table 6.1.10) in other countries, however, China’s energy consumption (shown in Table 6.1.9) is still 30% higher than that of the world’s average level. The gap of energy efficiency also exists between the domestic enterprises, i.e., main national enterprises, major local enterprises and others. It is a result of the differences in processing techniques, technology and management levels between these enterprises.

Table 6.1.9 Specific energy consumption of the iron & steel industry of China

Year 1980 1985 1987 1989 1991 1992 Specific energy consumption per ton of crude steel (toe/t-steel)

1.36 1.17 1.11 1.09 1.07 1.05

of which: Main national plants 1.10 0.99 0.94 0.81 0.81 0.79 Major local plants -- 1.21 1.19 1.01 0.93 0.89 Comparable energy consumption per ton crude steel (toe/t-steel)

of which: Main national plants 0.80 0.71 0.68 0.66 0.66 0.64 Major local plants 1.04 0.81 0.76 0.73 -- 0.68 Energy conservation per 104* yuan output value (toe/104yuan)

15.43 11.46 10.93 10.79 5.93 7.11

of which: Main national plants 15.01 11.24 10.91 9.63 6.31 7.11 Major local plants 20.03 14.87 12.26 12.94 5.53 5.19

Source: The Iron & Steel Industry Yearbook of China, 1993 Statistics of the Iron & steel Industry of China, 1993 Note: * at 1990 constant prices

Table 6.1.10 Energy consumption per ton of steel in selected countries (toe/ton)

Country 1980 1982 1984 1985 1986 1987 1988 1989 1990 World 0.575 - - 0.533 - - - - - China 1.360 1.170 1.110 1.090 France 0.549 0.569 0.527 0..521 0.478 0.467 - - - Japan 0.462 0.439 0.418 0.418 0.407 0.417 0.420 0.423 0.419Germany

0.513 0.506 0.487 0.505 0.501 0.465 - - -

UK 0.528 0.482 0.437 0.480 0.473 0.459 - - - USA 0.591 - - 0.513 0.497 0.473 - - - Brazil 0.489 0.488 0.503 0.493 0.463 0.484 - - - USSR 0.654 0.580 0.639 - - - - 0.545 - Korea - - - 0.383 0.355 0.365 0.369 - -

Source: Energy Office, MMI, 1990


6.1.3.3 Analysis of the energy conservation potential

Energy consumption in the iron & steel industry of China is still high, but shows a decreasing trend over the past years. With the large gap between the country’s specific energy consumption per ton of crude steel as compared with that of the developed countries, there exists a huge potential for energy conservation. The specific energy consumption per ton of crude steel is a comprehensive index reflecting the energy consumption level of the iron & steel industry. Many factors affect this index. In China’s case, the three major factors leading to the high specific energy consumption index in the iron & steel industry are:

- different calculation lines - unreasonable product structure, and - high energy-consuming processes.

A detailed energy conservation potential analysis would therefore be beneficial for the technical innovation and enhancement of energy management in the industry. Calculation line

The specific energy consumption per ton of crude steel is considered a reasonable index of the specific energy consumption of the industry in almost all countries. Due to the difference between the structures of the industry in various countries, however, the calculation lines also differ. Thus, calculated results are different and cannot be compared. In China, the iron & steel industry covers not only the procedures in mining, ore dressing, sintering, iron-making, steel-making, steel rolling, coke-making, and those for chemical products, e.g. ferro-alloy, & fire-resistant materials, but also some procedures unrelated to the iron/steel production process, such as coal washing, oil refinery, cement production, residential facilities, etc. Based on this scope, the calculated energy consumption level of China would be much higher than that of Japan, because Japan’s iron & steel industry does not include those procedures unrelated to iron/steel production. This difference in calculation would make a differential gap of 185.13 kgoe/t-steel. The comparable energy consumption per ton of crude steel in China’s iron & steel industry in Table 6.1.11 takes into account the energy consumed to produce one ton crude steel by those essential procedures from coking, sintering to finished rolling and process losses. This index is somewhat comparable with the specific energy consumption per ton crude steel in foreign countries, though differences still exist, as in the following example: the index of Japan does not include the value of losses and coking. This difference shows a gap of 289.33 kgoe/t-steel in 1987 and 267.33 kgoe/t-steel in 1990, respectively.


Table 6.1.11 Energy consumption of major processes in China’s iron & steel industry

Major process Energy consumption (% of total)

Sintering 9.65 Coke-making 8.93 Iron-making 32.3 Steel-making 12.0 Blooming 4.2 Rolling 10.1 Ore dressing 5.7 Gas-burning 0.72 Transportation 1.32 Loss 5.29 Machine fix, etc. 9.76 Total 100

Source: Energy Research Institute of Anshan Product structure

In China, the unreasonable product structure of iron & steel industry is one of the main reasons for the high energy consumption in the industry. The huge gap between China’s iron/steel ratio and that of the developed countries means China has a 100 kgoe higher energy consumption per ton steel than the developed countries. According to primary calculations, when the iron/steel ratio decreases by a factor of 0.01, a saving of 0.53 Mtoe a year is possible. China is therefore trying to decrease the iron/steel ratio to 0.9 by the year 2000. Following are the main measures being implemented:

• Decreasing the production of foundry pig iron Because the foundry pig iron needs higher furnace temperature and high silica content, its energy consumption is 10% higher than pig iron for steel making, and high foundry pig iron ratio means high energy consumption. Any decrease in the production of foundry pig iron will thus save energy.

• Higher waste steel utilization for steel making Using waste steel for steel production can decrease the production of pig iron for steel making, decrease the iron/steel ratio and save a great deal of energy. In 1983, the recycle ratio of waste steel was 31.6% in Japan, 48.2% in the US, and 44.8% in UK, while China achieved a figure of only 28.03% as of 1988.


In Japan, the electric furnace steel ratio is 30% while China’s ratio is 22%. Because the main raw material is waste steel, the higher the production of electric furnace steel, the lesser is the recycled waste steel proportion. Developing electric furnace steel and improving the steel production structure can therefore raise the recycled waste steel ratio and decrease the iron/steel ratio of China. In addition, developing new type of converter furnace - EOF - is an effective measure to raise waste steel utilization. EOF mainly uses waste steel as raw material, and it is very appropriate for China’s situation.

• Increasing the import of pig iron Because pig iron production needs high energy consumption, increasing the import of pig iron and decreasing the domestic production is another effective measure to reduce specific energy consumption of steel in the country. Energy consumption by process

A comparison of the specific energy consumption for the main processes in China’s iron & steel production and that of the developed countries is shown in Table 6.1.12. As indicated in the table, energy consumption in China is much higher than those of the other countries.

Table 6.1.12 Specific energy consumption for major processes in the iron & steel industry of China & other countries (kgoe/t-steel)

Year 1978 1980 1985 1990 AARR (%)*

Other countries

(1980) Coke-making 145.33 130.67 122.00 122.67 1.63 110.00 Sintering 69.33 63.33 56.67 51.33 2.70 46.67 Iron-making 347.67 354.00 339.33 339.33 0.97 300.00 Steel-making By open furnace

155.33 133.33 104.00 82.00

5.50

76.67

By Converter 95.33** 71.33** 26.00 18.67 -- 13.33 By electric furnace

268.67 254.00 216.67 197.33 2.62 156.67

Blooming 75.67 57.33 44.00 42.00 5.46 34.67 Rolling 187.33 104.67 101.33 90.00 6.45 60.00 Source: Collected by INET, Tsinghua University Note: * Annual Average Reduction Rate ** Contains the energy consumption of the iron-smelting oven 6.1.4 Environmental externalities of the iron & steel industry of China

Due to the use of outdated technologies in the industry during the initial period of development, not much attention was given to environmental protection, and the pollution problem in the metallurgical sector was serious. Awareness of environmental pollution started only in the 1980s. The government promulgated some decrees for environmental


protection, while the Metallurgy Ministry started to control pollution by carrying out measures for treatment and utilization of waste water, gas and slags (known as the three-waste comprehensive utilization). Technical upgrading was carried out in highly polluting plants, while the use of end-of-pipe technologies for waste treatment was promoted. Table 6.1.13 shows the situation of environmental pollution and its management in the iron & steel industry of China. Generally, there has been an increasing trend for water reuse in the industry, and water consumption per ton of steel has been decreasing over the years.

Table 6.1.13 Pollution and its treatment in the iron & steel industry of China Item Unit 1980 1986 1987 1989 1990 1991 199

2 Industry waste water reuse rate

% 60 71 72.8 74.95

76.07

77.84

78.27

Gross discharged waste water

103 ton

- 276.9

286.6

275.9

281.8

Discharged waste water per ton of crude steel

ton/ton

- 53.0 50.5 45.0 43.2 39.0 35.0

Water consumption per ton of steel

ton/ton

90.0

67 61.7 63.15

58.15

55.39

51.7

Treatment rate of waste water

% 12.6

72.0 84.3 91.23

93.21

94.01

94.34

Dust discharged per ton of steel

kg/ton

- 14.7 13.3 11.0 - - -

Treatment rate of waste gas % 25 79.5 83.1 86.81

86.95

88.92

89.9

Usage rate of metallurgical slags

% 10 76.06 77.41

76.69

74.75

76.53

79.19

Investment in pollution control

108 yuan

- 2.9 3.04 4.11 3.92 5.03 7.23

Output value of three-waste comprehensive utilization

108 yuan

- 3.5 6.3 8.65 9.45 13.84

16.37

Profit of three-waste comprehensive utilization

108 yuan

- 1.61 2.65 3.97 4.41 5.62 5.884

6.1.5 Potential for energy efficiency improvement and pollution abatement through

technological changes

6.1.5.1 Energy efficiency improvement in the iron and steel industry

The main reasons for China’s high energy consumption in the iron & steel industry are identified as follows:


• Low technical level

First, as compared to Japan’s technical level in the industry, the devices and facilities in China’s industry are backward and have a low average production capacity (Table 6.1.14). Second, the development of technologies for energy conservation is also slow. Many technologies which have been used widely in developed countries are not yet fully adapted in China. A comparison between the dissemination rate of technologies between China and Japan is shown in Table 6.1.15. As expected, dissemination rates in China are very low.

Table 6.1.14 Production capacity of devices and facilities in China and Japan Item Blast

furnaceConverter Electric

furnace Coke oven

Continuouscasting

Output (Mt) China 50.95 38.23 14.01 37.71 14.81 Japan 80.14 75.64 34.70 41.27 103.27 Devices (set) China 1130 171 1403 168 110 Japan 34 72 238 61 147 Per set output China 52 224 10 224 135 (103 ton/set) Japan 2357 1051 146 677 705

Source: Energy of Metallurgical Industry, Vol.12, No. 6, 1993.

Table 6.1.15 Dissemination of energy efficient technologies in China and Japan Energy saving Dissemination

rate* Energy Efficient Technology benefits

(kgoe/t) Japan(%) China(

%) Substitution of open furnace with converter 104 100 12 Direct rolling and loading with matting 24 50-60 5-6 Top recycling turbine (TRT) 10.67 92 16 Recovery of converter gas 20.67 90 40 Hermetic recovery techniques 4.67 2 0 Humidity adjustment & coal load in coke-oven 2 5 0 Continuous casting (CC) 16 93 22 Dry coke quenching (DCQ) 15.33 72 4 Source: News on Energy from the Metallurgical Industry, Vol. 10, 1992. Third, the recovery rate of waste heat and waste energy in the industry is not satisfactory. Due to the high temperature/high pressure nature of the iron & steel industry, a large quantity of waste heat and waste energy is produced and this has big potential for recycling. The rate of recovering this energy implies the level of efficiency in energy utilization.


Because of the problems in facilities, finance, techniques, and management systems, however, the recovery rate of waste heat and waste energy is much lower than that in developed countries, particularly in the technical sectors. They are as follows:

1) Dry coke quenching (DCQ)

The output of electricity by DCQ can be equal to 43.33 kgoe/t-coke, and can save about 23.33 kgoe of energy consumed per ton of crude steel. In Japan, the dissemination rate of DCQ has been more than 50% while in China, such technology is practically non-existent yet with the exception of the Shanghai Baoshan Iron & Steel General Corporation.

2) Top gas recycle turbine (TRT)

In Japan, more than 80% of the blast furnaces have introduced the facilities of TRT and have produced 2.9 TWh of electricity annually, representing 14.1% of the total output of electricity of the industry. In China, among more than 1000 blast furnaces, only 7 have been equipped with TRT and the annual output of electricity is only 0.23 TWh.

3) Gas diffusion from blast furnaces and coke ovens

In Japan, the diffusion ratios of gas from both blast furnaces and coke ovens are near zero. In China, the 1987 values were: 8.49% for blast furnaces and 2.67% for coke ovens in main national plants; and 18.5% for blast furnaces and 4.8% for coke ovens in major local plants.

4) Recovery of gas from converters

The application of the gas recovery techniques from the converter has been very popular in Japan, with average recovery rate of 103m3/t-steel or an equivalent of 17.33 kgoe in 1987. In China, only 14 of the 49 large/medium scale plants have been equipped with gas recovery facilities and most of them have very low recovery rates at about 30-40 m3/t-steel (with the exception of the Shanghai Baoshan Iron & Steel General Corporation and the Shouduo Iron & Steel Company).

The above-mentioned factors lead to an energy consumption gap of 53.33 kgoe/t-steel between Japan and China.

• Low level of operational management The energy management level may have a big influence on the energy consumption for a particular plant or process. It is estimated that an additional value of about 39.13 kgoe per


ton of crude steel is consumed in China (as compared to Japan) due to the backwardness of the energy management systems.

• Poor quality of resources and coal-oriented fuel structure China’s iron & steel industry relies mainly on domestic resources and fuels, characterized by lean iron ore and high ash content coal. Such conditions make it more difficult to promote energy conservation in China than in Japan where most of the resources and fuels, such as high quality iron ore & coal, are imported from international markets. In 1987, the average grade of iron ore was 52.17% in China, and 59% in Japan, with coke ash content of 13-14% in China’s main national plants as opposed to 10% in Japan. It is calculated that a gap of about 54.67 kgoe/t-steel is due to the two factors mentioned above. As has been pointed out earlier in Table 6.1.8, the proportion of coal in the energy consumption in China’s iron & steel industry has remained at about 70% during the past years, although that of electricity has been slightly increased to 24.2% in 1992. By experience, the energy equivalent ratio of electricity to oil and coal is 1.0:0.7:0.5. Hence, it is estimated that the high proportion of coal causes an additional energy consumption of 13.33 kgoe/t-steel in China, as compared to Japan. Following are the main technical measures being adopted in the iron & steel industry to reduce the specific energy consumption per ton of crude steel in the iron & steel industry.

1) Upgrading technologies for the sintering process

With technological updating, energy consumption of sintering process in iron & steel enterprises has decreased considerably from 1980 to 1990 (see Table 6.1.16).

Table 6.1.16 Energy consumption for the sintering process in China (kgoe/t)

1980 1985 1987 1989 1990 key enterprises 66 57 52 51 51 local enterprises 80 71 64 60 57

The main techniques used are as follows: - thick layer sintering - pellet ore production technology - new lighting devices which save energy

2) Energy conservation in coke making

In coke production, dry coke quenching (DCQ) and coal moisture control (CMC) technologies have been used for ten years in China. In key enterprises, the average energy


consumption for coke making decreased from 130.67 kgoe/t in 1980 to 122.67 kgoe/t in 1990. In local major enterprises, it decreased from 178 kgoe/t in 1987 to 122 kgoe/t in 1990. Because heat recovery rate of hot coke is still low and the water content of the coal which is used in the coke oven is high, the energy consumption in coke making is still higher than that of developed countries (as shown earlier in Table 6.1.12).

3) Energy conservation measures in iron making

Since 1980, energy conservation in iron making has been improving in China (Table 6.1.17).

Table 6.1.17 Energy consumption (kgoe/t) and coke rate (kg/ton) for the iron making process in China

1980 1985 1988 1989 1990 1991 A B A B A B A B A B A B

Major enterprises

354 535 361 519 335

507 337 519

339 525 339 524

local enterprises 409 627 390 639 359

626 371 627

371 622 361 615

Note: A - Energy consumption in kgoe/t B - Coke rate in kg/ton Main energy conservation measures used in iron making:

• Pulverized Coal Injection (PCI) technology Pulverized coal as a replacement for coke is injected directly into the blast furnace in order to save energy and raise profits. In the early 80s, this technology was used in large scale, with the injection amount increasing rapidly. By 1984, coal injection per ton iron was 54 kg.

• Top Recovery Turbine (TRT) technology in blast furnace The TRT technology is used to recycle the waste energy of blast furnace. Currently, 20% of the blast furnaces in China with volumes over 1000 m3 have TRT devices and more TRT devices are being constructed. Dissemination rate, however, is still low.

• Heat recovery of hot gas in blast furnace


20% of the blast furnaces in the industry are equipped with heat recovery devices and more devices are to be installed. Recovery rate, however, is still a problem.

• Oxygen Converter Gas recovery (OG) technologies 50% of converters with volumes of over 15 tons each are equipped with the OG system, though again, recovery rate is very low.

• Energy conservation measures in electric arc furnaces - Coal - Oxygen to aid in the melting process - Direct Current EAF: with the use of direct current EAFs, electricity

consumption per ton of steel can decrease by 3-5% while electrode consumption can decrease by 50%-60%. In China, DC-EAFs have capacities between 5 - 10 tons.

- Continuous Casting: continuous casting is an important energy conservation

technology. In 1980, continuous casting ratio was only 6.2% in China and this increased to 33% in 1990. The figure, however, is still very low compared with the developed countries.

• Technical measures in steel rolling - Technical updating of heating furnace in steel rolling - Energy conservation by heating of ingot

Through continuous efforts, energy consumption in some Chinese firms have improved a lot, but due to the large number of small scale plants with outdated technologies, the overall situation in the country’s iron & steel industry is not yet satisfactory. More effort is needed to promote energy conservation in the industry, such as enlarging the production scale of plants, raising the technical index of iron/steel ratio, continuous casting ratio, enhancing integrated energy, management and conservation, speeding up the development and dissemination of energy conservation technologies as well as the innovation and upgrading of major manufacturing devices. 6.1.5.2 Main Measures Used to Control Pollution in the Metallurgy Sector

In the area of pollution abatement, the following measures are being applied:

- Removal of dust from discharged gas of sintering machine, open hearth furnace and coke ovens. To transform the use of side-blow converter to top-blow converter in order to decrease the discharged smog.


- Raising the industry water re-use rate in order to decrease the water consumption per ton of steel, and increasing the treatment rate of waste water. In China’s case, the treatment rate increased from 12.6% in 1980 to 94.34% in 1992.

- Recovery of iron content in mud and more attention to the usage of metallurgical

slags. - Increasing the recovery rate of flammable gas in order to save energy and to get

rid of boilers which cause serious pollution. In China, recovery rate of gas from coke ovens and blast furnaces was over 90% in 1985, and has increased through the years. The recovery rate of gas from converters however, is low, with little increase over the years from 12% in 1985.

By means of the comprehensive utilization of waste gas and slags, the metallurgy sector can both control pollution and raise profit. Profit from the three-waste comprehensive utilization in 1992 was almost double that of 1980. Since almost two decades, the metallurgy sector of China has been engaged in environmental protection. Its investment on pollution control keeps increasing and environmental concerns are being taken into consideration in newly built or enlarged construction projects. The government promulgated some decrees to enhance energy management, such as Management Measures for Environmental Protection in Construction Projects, Stipulations on Environment Protection Responsibilities in the Metallurgical Industry (Provisional) and Stipulations on the Management of Environment Protection Facilities in Metallurgical Enterprises (Provisional). Meanwhile, R&D projects on environment protection in the metallurgy sector were also undertaken. As a result, over 100 achievements in environment protection research have gained recognition and have been cited for awards. These include:

- Purification of waste water - Smog control techniques and treatment of smog - Treatment and recovery techniques of metallurgical slags and mud

Hence, environmental protection in the metallurgy sector of China has made great progress and is keeping pace with the developments in steel production. Compared with the developed countries of the world, however, the techniques and management in the industry are still at a low level and pollution remains a serious problem. This poses a challenge to the industry and to the country as a whole 6.1.6 Status of application of new technologies

Since energy conservation began in 1978, the specific energy consumption per ton of crude steel in China has been reduced from 1.68 toe in 1978 to 1.05 toe in 1992 at a rate of 37.5% or an average annual rate of 3.31%. During the past 14 years, the cumulative energy conservation reached 24.47 Mtoe with three periods to characterize the cycle.


First period (1978-1982)

The starting period focused on improving public consciousness on energy conservation, enhancing the management of energy utilization, reducing the waste and loss of energy, etc.. The cumulative amount of energy conserved was 13.78 Mtoe and the annual average saving rate was 6.78% during this period.

Second period (1982-1986)

This period saw the start of expansion and branching activities of the iron & steel plants to iron ore, ferro-alloy, carbon, and fire-resistant materials. Energy conservation laws were also implemented. About 30 efficient techniques, such as gas recovery of converter, continuous casting, waste heat & energy recycle, etc., were introduced. An annual energy savings capacity of 1.51 Mtoe was realized during the period, and the annual average energy savings rate was pegged at 2.75%. Third period (1987- present )

This period is known as the integrated energy savings period. During the past ten years or so, remarkable achievements in energy conservation has been made in a number of cases. But due to the trend of ‘high quality- and high level-oriented production but little investment’ in small scale enterprises, the average annual savings rate was considerably reduced to less than 1%. In general, the industry’s energy conservation efforts are summarized as follows:

• Energy management has been given importance in the management system of the plants

Through continuous efforts since 1978, an efficient energy management system has been established in the industry sector, which includes a professional energy management team with thousands of staff, and the implementation of a large number of fundamental projects for energy conservation. Since energy measurement has been treated seriously as a major part of energy management, the accuracy of the measurement has been improved to provide a base for developing the management level. At present, not only are the computer-based energy statistic systems being widely used in China’s metallurgical plants, other methods such as the norms and standards for heat balance test of the major devices and furnaces, energy balance test for plants or works, electricity balance and water balance test, etc., have also been introduced, and the standardization of energy consumption quota has been implemented. A series of laws and regulations for energy conservation have also been


formulated to speed up the development of energy conservation into a more systematic, standardized and normalized procedure.

• The old pattern of the iron & steel industry development mainly relying on the state supply has been modified to a new one which relies mainly on energy conservation.

From 1980-1990, the energy consumption increased by only 39.2% while the output of iron & steel increased by 80.5%. The industry has been aiming to reach at least half of the rising demand in energy through energy conservation, and the other half through additional state supply. During this period, the target has been reached and the lack of energy which has been restricting the development of the industry has been alleviated.

• The structure of energy consumption of the iron & steel industry has become more suitable to Chinese conditions

Since 1978 when the Central Government announced the reduction in the quota of fuel-oil, the proportion of oil in the total energy consumption of the industry sector has been decreasing to less than 7%, a situation which is more fit for Chinese conditions.

• A sound technical capacity for energy conservation has been established through the dissemination of a series of energy efficient technologies.

During the “sixth five-year plan” period, more than 780 energy saving projects, including fundamental construction and technical innovations, were implemented. This led to an energy saving capacity of 1.51 Mtoe, with a share of about 20% of the practical consumption during the same period. During the seventh five-year plan period, the numbers rose to 700 energy saving projects, with 2 Mtoe energy savings and 40% share of practical consumption. Typical demonstration techniques are CC (continuous casting), CDQ, TRT, converter gas recovery. Various energy centers provide available experiences and lessons for future energy conservation programs.

• The energy consumption index has been reduced on the whole

The specific energy consumption per ton of crude steel was reduced by 37% during the period 1978-1992. In view of comparable energy consumption, the value in the main national plants was reduced to 643 kgoe/t-steel, or 31.14% lower than that in 1978. Those of the major local plants were 682 kgoe/t-steel or 55.07% lower than the value of 1978. With regards to the energy consumption of processes, the values of large and medium scale plants in 1992 were 8.35% and 47.2%, respectively, lower than those in 1978.


6.2 Country Report: India

6.2.1 Introduction

The removal of price and distribution controls on iron and steel on 16 January 1992 led to increased input costs of integrated steel plants. After some increase in material price following the price revision by steel manufacturers, the prices of steel goods have stabilized throughout the country. Steel imports of any kind are now freely allowed. At the same time, the import duty on steel melting scrap was reduced from 35% to 10%, 55% to 35% for pig iron, and from 65% to 45% on billet and HR coils. This had a moderating effect on market prices. Table 6.2.1 shows the performance of the sector in the economy over the period 1973-74 to 1988-89.

Table 6.2.1 Performance of the Indian iron & steel industry in 1973 to 1989 (000,000)

1973-1974 1978-1979 1983-1984 1988-1989 Number of factories

942 1332 1689 1829

Fixed capital (Rs) 83946 218326 449999 802450 Fuels consumed (Rs)

11551 43495 95968 158830

Value of output (Rs)

109070 288748 664372 1417514

Depreciation (Rs) 8930 13724 24820 75798 Net value added (Rs)

23854 56869 131791 257728

Real Growth Rate % share in the manufacturing

economy 1973-

74 1978-

79

1978-791983-84

1983-84 1988-89

1983-84 1988-89

Number of factories

7.17 4.83 1.64 1.51 1.76

Fixed capital 11.58 10.10 0.1 9.54 9.00 Fuels consumed 21.85 3.99 0.92 15.83 11.20 Value of output 12.98 4.98 0.69 6.51 7.68 Depreciation 9.29 10.64 Net value added 10.46 5.15 4.68 5.92 7.44

The production of salable steel by integrated steel plants (main producers) in the year 1991-92 was 10.57 million tons (Mt) which recorded a growth of 13.3% as compared to 1990-91 production levels. The output of finished steel in the secondary sector declined by 1.6% in 1991-92 because of the inadequate availability of imported melting steel scrap and a fall in demand. There was also a deceleration in the growth of production of salable pig iron by the


main plants from 12.1% in 1990-91 to 6.5% in 1991-92 which reflected the slow down in the forging and casting industry. The production of salable steel in April-December 1992 increased by 8% over the corresponding period in 1991. The production of finished steel in 1992-93 was expected to go up reflecting the beginning of a recovery in capital goods and engineering industries.

There was a modest recovery in the production of steel in 1990-91. The production of salable steel by the seven integrated steel plants during the year (including Visakhapatnam Steel Project which commenced production in 1990-91) was 9.53 Mt, which was 5.5% higher than the 9.03 Mt production in the previous year. SAIL improved its capacity utilization from 81% in 1989-90 to 84% in 1990-91. The Tata Iron & Steel Company’s (TISCO) production slipped marginally by 1%. As a major policy change, the government is now encouraging the production of steel in the secondary sector by licensing new units which are based on new energy saving technologies and the use of sponge iron in place of conventional scrap iron. A substantial fall in the production of salable pig iron by the main steel plants was experienced in 1990-91 brought about by the removal of price and distribution controls. All SAIL plants except TISCO curtailed their planned production of pig iron to concentrate on the production of higher value added steel items than on the uneconomic production of pig iron. The demand for pig iron during 1990-91 was estimated at 185 Mt. The government also decided to permit the production of pig iron in the secondary sector. This reduced the pressure on integrated steel plants. The secondary steel sector has grown rapidly in terms of number of plants, and has resulted in an increase in energy consumption over the years.

6.2.2 Technological trajectory of India’s iron & steel industry

6.2.2.1 Structure of the Indian steel industry: capacity and production

Commercial production of steel started in India in the year 1907 when the Tata Iron & Steel Company at Jamshedpur came into existence. In 1919, the Indian Iron & Steel Company (IISCO) was established and in the year 1923, Mysore Iron & Steel Works came into existence. The trend in the installed capacity for producing crude steel according to ownership may be observed from Table 6.2.2. It would be seen that (i) the installed capacity has increased 11 times during the period from the late 1940s to 1990s to reach a level of 25.4 million tons (Mt); (ii) public sector accounts for 55% of the present installed capacity; and (iii) the installed capacity in mini-steel plants forms nearly one-fourth of the total capacity. To study the trends in production, it is necessary to consider not only the production of crude steel but also that of hot metal and finished steel. This is because hot metal, which is produced at the blast furnace, can either be used for the casting of pig iron or for making crude steel. Similarly, the ingot steel can either be made into salable finished steel or into semis (blooms,


billets and slabs) which are sold to re-rollers. Table 6.2.3 lists the total production of steel between 1951 to 1992.

Table 6.2.2 Growth in installed capacity of crude steel (million tons)

Units Late 1940s Mid 1960s March 1993 Private Sectors: TISCO 1.7 2.0 2.5 IISCO 0.5 1.0 - Mini-steel plants 0.1 0.5 9.0 Sub-total 2.3 3.5 11.5 Public Sector: IISCO - - 1.0 ROURKELA - 1.0 1.8 BHILAI - 1.0 4.0 DURGAPUR - 1.0 1.6 BOKARO - - 4.0 VIZAG - - 1.5 Sub-total 0 3.0 13.9 Total 2.3 6.5 25.4

Table 6.2.3 Trends in steel production (Mt)

Year Hot metal

Crude/ingot steel

Finished steel

1951 1829 1503 1091 1961 4405 3418 2237 1971 7030 6302 4793 1981 8554 9385 7903 1982 9691 10764 9384 1992 14412 16219 14692

The secondary steel sector is mainly represented by the small and medium scale plants using electric arc furnace and induction furnace technologies. Seven integrated steel plants are under operation in India at present. The steel manufacturing capacity in India has increased by 22.5 Mt of ingots per year. Of this, integrated steel plants account for 17.3 Mt In addition there are 211 arc furnaces (called mini steel plants) with a total capacity of 7.9 Mt of ingots per year. In 1988-89, integrated steel plants contributed 10.6 Mt towards the total production of steel. 6.2.2.2 Product mix and capacity utilization

TISCO exhibits the highest capacity utilization in the industry (Table 6.2.4). The conversion of hot metal into salable pig iron is marginal in TISCO, which implies that the total hot metal produced at the blast furnaces is being fully utilized for steel making. On the other hand, SAIL units, particularly Bhilai and Bokaro produce substantial quantities of pig iron for sale. The pig iron thus sold caters to the foundry industry of the country.


Table 6.2.4 Product mix (1000 tons) and capacity utilization (%) in 1986-1987

Company Hot metal Crude/ingot Steel Finished steel TISCO 1940 (97) 2250 (97) 1907 (107) BHILAI 2510 (80) 2230 (66) 2150 (80) BOKARO 2813 (61) 2056 (66) 1745 (83) ROURKELA 1223 (76) 1100 (61) 1140 (93) DURGAPUR 1125 (66) 922 (58) 751 (61) IISCO 825 (63) 528 (53) 526 (66)

6.2.2.3 Trends in the steel making process

All over the world, the open hearth furnace route to steel making in the 1960s gave way to the basic oxygen furnace and electric arc furnace in the eighties. In 1992, steel manufacturing from open hearth furnace was totally eliminated in the US and Japan. Electric arc furnace route for steel making which was insignificant in the 1960s has gained momentum and now represents 30% of steel making in the US and 31% in Japan in 1992. The use of electric arc furnaces for steel making in India has made considerable improvement in 1990-1992. Sponge production through direct reduction process has also gained acceptance. The trends in the steel making process in Japan, the USA and India for the basic oxygen furnace, open hearth furnace and electric furnace are graphically shown in Figures 6.2.1 to 6.2.3, respectively.

. 1 9 6 0 1 9 8 2 1 9 9 2

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

%

1 9 6 0 1 9 8 2 1 9 9 2

U n ite d S ta te s

J a p a n

In d ia

Figure 6.2.1 Comparative trend in the use of basic oxygen furnace for steel making

1960 1982 1992

0102030405060708090

%

1960 1982 1992

United States

Japan

India

Figure 6.2.2 Comparative trend in the use of open hearth furnace for steel making


1960 1982 1992

0

10

20

30

40

50

60

70

%

1960 1982 1992

United States

Japan

India

Figure 6.2.3 Comparative trend in the use of electric furnace in steel making

Source: 1960 Data - United Nations Economic Commission for Europe, Structural Changes in

the Iron & Steel Industry, 1979; 1982 Data - International Iron & Steel Institute; Indian Data - SAIL

In India, the conversion from open hearth to oxygen furnace is progressing at a slow pace. However, all the new capacity additions are basic oxygen furnaces. The modernization and substantial expansion programs of the integrated steel plants show a commitment to adopt basic oxygen furnace in their plants. 6.2.3 Evolution of energy efficiency in the iron & steel industry of India

6.2.3.1 Energy and material consumption

The primary sources of energy in steel plants are coking and non-coking coal, liquid hydrocarbons and electricity. The two energy intensive steps in this industry are iron making in the blast furnaces and the production of liquid steel from the hot metal in blast furnaces. Iron making in the blast furnaces consumes nearly 70% of the total energy input into the system whereas net energy consumption is 416.8 kgoe/ton of hot metal in TISCO, and 703 kgoe/ton in the Durgapur Steel Plant. These figures are both higher by 39% and 180%, respectively, compared with UK consumption standards. Table 6.2.5 shows the energy consumption in sponge iron steel plants in the country, while Table 6.2.6 shows the detailed unit-wise material consumption per ton of hot metal products in blast furnace processes from various plants in the Indian iron & steel industry.

Table 6.2.5 Energy consumption per ton in sponge iron plants in India

Fuel Coal-based Gas-based Coal (tons) 1.2 - Natural Gas - 290 Electricity (kWh) 110 150 Light Diesel Oil (liters) 9 - High-speed diesel oil (liters)

3.5 -


Table 6.2.6 Blast furnace specific material consumption rates (1988-89 to 1992-93) ---------------------------------------------------------------------------------------------------------------------- Materials/ Unit 1988-89 1989-90 1990-91 1991-92 1992-93 Services ----------------------------------------------------------------------------------------------------------------------------------- Bokaro Steel Plant: Iron Ore kg 644 636 531 428 426 Sinter kg 1020 1044 1146 1180 1207 Coke (dry) kg 666 664 708 660 663 Durgapur Steel Plant: Iron Ore kg 934 972 936 905 793 Sinter kg 663 683 717 750 850 Coke (dry) kg 856 858 817 805 887 Rourkela Steel Plant: Iron Ore kg 1059 987 828 773 871 Sinter kg 826 886 953 910 879 Coke (dry) kg 736 725 728 709 740 Indian Iron & Steel Co. Ltd.: Iron Ore kg 1491 1518 1474 1423 1484 Scrap & Scale kg 78 90 75 33 27 Coke (dry) kg 1023 1017 947 866 866 Visakhapatnam Steel Plant: Iron Ore kg Nil Nil 182 302 363 Sinter kg Nil Nil 1544 1286 1216 Coke (dry) kg Nil Nil 658 596 580 TISCO: Iron Ore kg 1020 807 645 570 541 Sinter kg 543 763 981 1032 1059 Coke (dry) kg 716 714 674 658 676 ----------------------------------------------------------------------------------------------------------------------------------- The unit-wise energy consumption for various centers of the steel making (open-hearth) process from different plants in the industry are given in Table 6.2.7. Efforts to reduce specific energy consumption in steel melting furnaces with higher productivity led to the introduction of basic oxygen furnace (BOF), replacing the old open hearth furnace (OHF) of making steel from hot metal. BOF consumes much less energy. In India, OHF is declining rapidly and LD converters and electric arc furnaces are becoming more prominent. The Indian steel industry has suffered from a number of disabilities. Obsolete plants machinery and technology have been important factors contributing to low capacity utilization and productivity on the one side, and higher energy consumption and production costs on the other. It is interesting to note that unlike today, the Indian steel industry was internationally competitive in the 1960s.


Table 6.2.7 Specific energy consumption rates of steel melting shop (1988-89 to 1992-93)

----------------------------------------------------------------------------------------------------------------------------------- Materials/ Unit 1988-89 1989-90 1990-91 1991-92 1992-93 Service ----------------------------------------------------------------------------------------------------------------------------------- Bhilai Steel Plant: Hot Metal kg 844 866 934 909 918 Scrap (Iron/Steel) kg 284 291 282 278 264 Bokaro Steel Plant: Hot Metal kg 951 960 960 936 939 Scrap (Iron/Steel) kg 179 180 185 203 201 Durgapur Steel Plant: Hot Metal kg 865 878 865 865 866 Scrap (Iron/Steel) kg 218 220 230 239 267 Indian Iron & Steel Co. Ltd.: Hot Metal kg 489.9 999.7 1010.3 941.0 941.4 Scrap (Iron/Steel) kg 171.2 221.2 229.2 277.1 270.6 Visakhapatnam Steel Plant Hot Metal kg Nil Nil 942.84 949.72 947.29 Scrap (Iron/Steel) kg Nil Nil 142.82 151.49 146.98 TISCO: Hot Metal kg 639 661 719 711 709 Scrap (Iron/Steel) kg 531 494 488 478 503 ----------------------------------------------------------------------------------------------------------------------------------- Gross specific energy consumption

The total energy input from coking coal, non-coking coal, liquid hydrocarbons and purchased electricity, when related to the total production of cast crude steel or finished salable steel gives the gross specific energy consumption. The derived gross specific energy consumption of the steel units in 1986/87 may be observed from Table 6.2.8.

Table 6.2.8 Gross specific energy consumption (1986-1987) - in toe/ton

Company Crude steel Salable steel TISCO 1.030 1.216 BHILAI 1.258 1.305 BOKARO 1.496 1.763 ROURKELA 1.356 1.309 DURGAPUR 1.525 1.872 IISCO 2.070 2.078

The above figures of gross specific energy consumption are influenced by the following :


1. Salable outputs of steel plants are (a) finished product and (b) semis which are not rolled to finished products. The type of finished product as well as the quantity of semis varies from plant to plant.

2. As the raw materials get processed and become intermediate products, different process centers consume different amounts of energy per unit output of the process center - some are energy- intensive processes and some are not.

3. Cast crude steel production (mostly ingot) is achieved through the different routes of production by the plants - some exclusively by open hearth processes, some only by LD converters and some by a combination of both. Hence, the gross specific energy consumption needs to be worked out on the basis of balanced flow energy consumption whereby the carry-over energy of a particular process center is taken into consideration in the next process center. This is being adopted in the present study.

Balanced flow energy

The cost of energy has two components - one being the quantity of energy consumed per unit output and the other being the unit cost of the energy consumed. Since the quantitative consumption of energy per unit output is based on output in terms of cast crude steel, the quantity of energy consumed should be based on balanced flow energy as adopted in international practices. Table 6.2.9 shows the balanced flow energy consumption in toe per ton of cast crude steel. The balanced flow of energy consumption is a concept developed by the International Iron & Steel Institute and followed all over the world. It takes into cognizance the carried-over energy by the material which is used in a given process center and then the additive value for the entire plant is determined through calculation of balanced flow energy.

Table 6.2.9 The balanced flow energy consumption based on the IISI method (energy consumption in toe/ton of crude steel)

----------------------------------------------------------------------------------------------------------------------------------- Company 82-83 83-84 84-85 85-86 86-87 87-88 88-89 89-90 90-91 91-92 ----------------------------------------------------------------------------------------------------------------------------------- BHILAI 0.905 0.893 0.898 0.97 1.055 1.02 0.927 0.885 0.865 0.836 BOKARO 1.079 1.096 1.054 1.082 1.063 0.993 0.94 0.925 0.910 0.886 ROURKELA 1.346 1.292 1.134 1.112 1.165 1.099 1.062 1.023 1.006 1.000 DURGAPUR 1.081 1.176 1.250 1146 1.203 1.155 1.141 1.166 1.126 1.067 IISCO 1.631 1.641 1.966 1.547 1.580 1.613 1.674 1.642 1.608 1.39 TISCO 1.055 0.999 0.976 0.968 0.916 0.934 0.956 0.962 0.983 0.930 ----------------------------------------------------------------------------------------------------------------------------------- Source: BICP Report on Energy Audit of Integrated Steel Plant and SAIL reply. For reasons already mentioned in relation to specific energy consumption, the balanced flow energy consumption also shows variations among the companies and over time in the same


company. From the above table, it can be seen that the Bhilai steel plant has achieved specific energy consumption of 0.836 toe per ton of crude steel. The plant is currently routed as one of the best steel plants in India. In the case of TISCO, its specific energy indices were reduced from 1.05 in 1983 to 0.91 in 1986-87. The specific energy consumption of 0.98 in 1990-91 marginally decreased to 0.93 in 1991-92. However, most of the steel plants have shown remarkable reduction in specific energy consumption and have maintained lower specific energy indices with declining trends from 1987-88. The reduction is mainly attributed to the change from open hearth furnace to basic oxygen furnace in the integrated steel plant. The adoption of continuous casting process is one of the major trends in almost all Indian integrated steel plants. At the relatively new modern steel plant at Visakhapatnam, adoption of dry quenching of coke and continuous casting process is expected to result in lower specific energy consumption. 6.2.3.2 Energy consumption at the process centers

For each of the process centers, energy consumption per ton of output has been computed for each of the Indian integrated steel plant. This would enable comparison of energy intensity of Indian plants and the scope for energy conservation in each process center with efficient plants abroad. For purposes of international comparison, energy consumption of British Steel Corporation is used as the reference. Table 6.2.10 summarizes the position of Indian plants with respect to energy consumption for the process center using weighted average figure for the last five years. Table 6.2.10 Process-wise energy consumption in the iron & steel industry (kgoe/ton)

Process Center 1 2 3 4 Output Sinter Gross coke Hot metal Ingot TISCO 70 204 417 106 BHILAI 81 233 - 117 BOKARO 93 226 570 - ROURKELA 92 232 488 157 DURGAPUR 87 234 703 209 IISCO - 234 498 201 BRITISH STEEL CORP.

55 155 322 -

In the blast furnace center, the most energy-intensive process takes place. Here, iron ore, coke and fluxing material are converted into hot metal. Coke supplies the major portion of the thermal energy necessary for reducing iron into hot metal. Blast furnace gas constitutes a source of by-product energy. Net energy consumption in 1986/87 formed 65 to 73 per cent of gross energy consumption. Net energy consumption in Indian plants varies from 416.8 kgoe/ton of hot metal in TISCO to 703 kgoe/ton in DSP. These figures are higher by 29% and 118%, respectively, than the consumption of 322 kgoe/ton in the U.K.


For the sinter process center, the minimum weighted average consumption was 70 kgoe in TISCO and a maximum 93 kgoe in Bokaro. These are higher by 26% and 68%, respectively, as compared to the consumption in British Steel Corporation (55 kgoe per ton of sinter). Net energy consumption in the coke ovens forms about 51 to 68 percent of the weighted average of net energy consumption. This varies between 203.8 kgoe per ton of coke produced in TISCO to 234 in IISCO, and is 32 and 52% higher than the achieved net consumption of 159 kgoe in the BSC. Durgapur and TISCO do not possess basic oxygen furnaces and net energy consumption varies between 27 kgoe per ton in Rourkela to 48.8 kgoe per ton in Bokaro. Rourkela’s performance is 16% lower than the consumption in the UK plant, whereas Bokaro is higher by 62%. The traditional procedure in continuous casting is to reheat the ingots cast from liquid steel at the soaking pit and roll it into semis. Energy consumption figures at the Bhilai Steel plants compare favorably with that of the UK plant while consumption in TISCO is 43% higher. Nearly 70% of the energy consumed in this center is in the form of electricity. 6.2.3.3 Specific energy consumption

Steel making is an energy intensive process. At every stage in steel production from coke making to the finished steel product, a large quantity of thermal energy is consumed. In addition, considerable electrical energy is required, though it is much smaller in proportion to thermal energy. Integrated steel plants in India have generally adopted the conventional blast furnace-open hearth furnace (OH) - basic oxygen furnace (BOF) - ingot/continuous cast rolling mill route for making steel. The open hearth process still dominates the Indian steel industry unlike that in developed countries, where more than 80% of steel production is through BOF - continuous casting route. The specific energy consumption in Indian steel plants is between 900 to 1200 kgoe/ton crude steel, whereas in developed countries, this is about 500 to 600 kgoe/ton of crude steel. Cooking coal and steam coal contribute over 95% of the total energy input to the plant and the rest comes from furnace oil, light diesel oil, low sulfur heavy stock oil, high diesel oil, and purchased power. The contribution from fuel oils is 4% of the total energy input.

6.2.3.4 Energy saving measures implemented in recent years

Energy conservation measures are mostly realized through proper maintenance and control of processes, and by the modification of various process equipment. SAIL plants have implemented projects towards the reduction of specific oil consumption in the country for steel production, and by regularly finding ways to reduce power consumption. Some of the


short term measures implemented for energy efficiency improvement are summarized in Table 6.2.11. Energy Conservation Measures Implemented in Indian Steel Plants in 1993-94

BHILAI steel plant

- Replacement of 1000 W HPMV lamps by 400 W HPSV - Renovation of illumination of stacking area of ore handling plant - Auto switching of field motors in plate mill - Remote operation of DFG burners at P & BS - Replacement of HPMV with HPSV lamps in mills and sinter plant-I

DURGAPUR steel plant

- On-line sealing of blast leakages in blast furnaces - Lagging of steam pipe lines

ROURKELA steel plant

- Installation of free flowing screens in sinter plant - Oxygen enrichment of blast in blast furnace No.3 - Tar and oil flow meters for SMS, reheating furnaces, etc.

BOKARO steel plant

- Static AC speed regulation of gas storage fan of SMS-II - Conversion of high bay HPMV and 300 GLS fittings with 640 HPSV fittings in SMS

area - Procurement of 7 infra-red pyrometers and 4 oxygen analysers - Procurement and installation of electronic ballasts in fluorescent tube-light fittings in

the shop areas - Aluminum sheet cladding of 39 ATA steam lines from TPP to BPP

IISCO

- Ceramic welding to prevent cross wall leakages in coke ovens - Energy consumption of 825 kgoe/ton of crude steel has been achieved by BSP

Table 6.2.11 Cost effective measures/schemes implemented in SAIL in 1988-1992

S.No. Measure Pay Back Savings Investment Period Expected Cost (Rs 106) (Rs 106) 1. Insulation of recuperators at reheating furnaces, 3 years 20 60


improved microprocessor-based control instruments (1989-91) 2. Installation of recuperators at Strip Mills (1989) 2.5 years 50 125 3. `G' Blast Furnaces (1992-93) 5.2 years 34600 18000 4. Stamp charged Facility at Coke Oven Battery No. 6 10 years 12200 12200 (1992-93) 5. 500 Ton Oxygen Plant B.S.Shop i) Ceramic Recuperators (1990) 3 years 0.5 1.5 ii) Regenerative Ceramic Burners (1992) 3 years 40 12 S.No. Measure Cost Pay-back period (Rs 106) 1. Insulation of cold blast mains for blast furnaces 30.8 6 months 2. Replacement of conventional roof sheets by fiber 33.7 15 months reinforced translucent sheets for day lighting in floor shops 3. Time switches for switching off of street lights 3.9 12 months 4. High emissivity coating for walls of high 1.9 7 months temperature furnaces 5. Effective steam straps on steam lines 11.5 4 months 6. Low steam pressure burners for oil firing 10.6 25 months in reheating furnaces 7. Thermal insulation of fuel oil tank 6.8 10 months 8. Ceramic fiber lining for annealing furnaces 5.0 24 months 9. On-line steam leakage plugging 1.8 2 months 10. Modified water cooled skids in reheating furnaces 4.5 2 months 11. Modified ladle heating stand 17.3 19 months 12. Oxygen analyzer and other equipment for reheating 12.0 10 months furnaces 13. Electrical tape heating of liquid fuel lines 7.9 5 months 14. Double skid insulation for reheating furnaces 8.0 2 months 15. Conversion of HPMV and GLS to HPSV fittings 12.9 13 months -----------------------------------------------------------------------------------------------------------------------------------

- 25 kg coke per ton of hot metal produced is saved by achieving a coke rate of 641 kg/THM at BSP.

- Recycling of sinter plant dust to the system leads to about 5% saving of iron ore materials at DSP.

- Saving of 10,000 ton/year of iron ore fines from LD dust collected from SMS GCP at RSP.


- Saving of 1,60,000 liters of lubricant oil collected from oil reclamation system in rolling mill pump house at RSP.

- Recycling solid wastes in sinter plant, there is a saving in iron ore fines and limestone which amounts to Rs 23 million at BSL.

6.2.4 Environmental externalities of Indian iron & steel industry

The making, shaping and treating of steel involves several intricate processes from the raw-materials to the finished products. The major significant emissions are encountered in the sintering plant, coke ovens, blast furnace, steel making and rolling plants. 6.2.4.1 Pollution-areas in Indian iron and steel industry

The major sources of pollution to water bodies are as follows: - coke ovens and by-product plants of phenol, cyanide, oil and grease, totally

dissolved solids and suspended solids - sintering plant for suspended solids - blast furnace and steel melting shop, total dissolved solids and suspended solids - mills for acidic wastes, oil and grease - power plants for suspended solids

The major sources of air pollution are:

- dust from coke ovens, sintering plant, blast furnaces, steel melting shop, refractory materials plant and power plants

- SO2 from coke ovens, sintering plants and other areas using coke oven and blast furnace gases

Noise pollution are also caused by the following:

- boiler plants, pumps and compressor rooms, finishing bays of rolling mills - points of steam and compressed air leakages

Other solid waste sources are:

- coke breeze from coke ovens - iron ore dust and sludge from blast furnace and steel melting shop - blast furnace slag - steel making slag - mill scales - fly ash from power plants - limestone and dolomite dust from refractory materials plants and steel melting shop - used refractory bricks

At the mines, the main air pollution comes from the dust generated at crusher houses and stockpiles. The source of water pollution is suspended solids from washing plants while noise pollution is generated from blasting related to mining activities


6.2.4.2 India’s environmental standards for pollution control and abatement

The Water (Prevention & Control of Pollution) Rules of 1978 stipulated a maximum use of 20 m3 of water per ton of finished steel for the integrated iron & steel industry. The Environment (Protection) Rules of 1986 Schedule 1 under Rule 3 have fixed the following particulate matter emission standards for the Integrated Iron & Steel Industry (Table 6.2.12).

Table 6.2.12 Emission standards for particulate matter in the integrated iron & steel industry of India

Process Area and/or Process Standard Sintering plant 150 mg per normal cubic meter Steel making during normal operations 150 mg per normal cubic meter Steel making during oxygen lancing 400 mg per normal cubic meter Rolling mill 150 mg per normal cubic meter Carbon monoxide from coke ovens 3 kg per ton of coke produced Refractory material plant 150 mg per cubic meter

Effluents Concentration in mg per liter except for pH

Coke oven: By-product plant pH 6 - 8 Suspended solids 100 Phenol 1.0 Cyanide 0.2 BOD (5 days at 20oC) 30 COD 250 Ammoniacal nitrogen 50 Oil and grease 10 Other plants such as sintering plant, blast furnace, steel melting and rolling mill

pH 6 - 8 Suspended solids 100 Oil and grease 10

6.2.4.3 Pollution control equipment installed in Indian iron & steel industry

Most Indian integrated steel plants were installed more than 30 years back. Because of the large sizes of plants, a great number of pollution control equipment was provided with the main plants. These mainly covered the areas of air and water pollution control. A summary of the type and number of control equipment installed at the five integrated steel plants is given in Table 6.2.13.


These equipments, along with many other smaller control devices were installed gradually over a period of time in the main plants at various steel plants. Some of these control equipments are functioning satisfactorily while others require revamping/modifications. A campaign was launched in all integrated steel plants to undertake necessary revamping/refurbishing and putting back the non-functioning or malfunctioning control equipments into operation by the end of 1993.

Table 6.2.13 Pollution control equipment employed in the integrated steel plants of India

Air pollution control: Number of units Wet scrubbers including venturi scrubbers 415 Cyclones including multi-cyclones 300 Bag filters 118 Electrostatic precipitators 87 Miscellaneous 69 Total 1001 Water pollution control: Bacteriological oxidation plant 3 Acidic waste neutralization plant 5 Thickeners/clariflocculators/settling tanks 55 Vacuum filters 2 Oil and grease catching plants 39 Oxidation ponds 18 Sewage treatment plants 11 Miscellaneous 28 Total 161

6.2.5 Potential for energy efficiency improvement and pollution abatement through technological changes

6.2.5.1 Energy efficiency improvement through energy conservation

Constant emphasis and continuous endeavors to employ environmental assessments have resulted in a significant reduction in the specific energy consumption at all SAIL plants. The energy consumption is being reviewed meticulously through economic as well as environmental angles. Energy conservation measures mostly realized by improving the operational and maintenance practices and by the modification of various equipments are being followed at all SAIL plants. The approach towards reduction of input energy costs of the steel industry like reduction of coal to hot metal ratio, reduction of specific fuel consumption, improvement of recovery of by-product fuels, and reduction of power consumption form the regular features in the implementation strategy of SAIL plants. Some short term measures aimed at conservation are:

- Increasing sinter percentage in BF - Increasing scrap consumption in SMS


- Improving coke oven gas yield - Reducing tap to tap time - Improving heat size in SMS - Maximize BF gas yield

The long term measures incorporate new technologies, equipment and computer controls for processes etc. Some such measures which are being implemented in various plants are:

- Introduction of BCC in coke ovens - Computerized control in combustion and thermal regions of coke oven - Recovery of waste heat from sinter coolers - Replacing OHF by BOF - Automatic speed control of blowers, exhausters and compressors to save energy - Introduction of efficient energy monitoring and auditing system through

computerization Future measures which shall further cut down energy cost (mainly through recovery) and help to attain operating standards at par with advanced steel making countries are:

- Dry quenching of coke in coke ovens of SAIL plants - Generation of power by using BF to gas flow - Use of natural gas through BF tubers

6.2.5.2 Potential for pollution abatement through management and technology

Pollution management strategy

The integrated steel plants realize that technology and equipment alone are not adequate for successful pollution management. These must be complemented by awareness among its employees and integrated into the operational and maintenance practices. This concept forms the backbone of the integrated steel plants' pollution management strategy. Some of the areas identified for air pollution management are:

- on-main charging, dust free pushing, self sealing doors and silica welding of walls in coke oven batteries

- process and production efficiency and centralized electrostatic precipitators at sintering plants.

- screening and upgrading of dust collection units at refractory materials plant - energy recovery from cleaned gases and process change from open hearth to BOF

in steel making shops - adaptation of electrostatic precipitators at power plants to suit Indian coal quality.

Areas for water pollution management include:

- increased recycling after suitable treatment - treatment at source rather than tail-end treatment


- bacteriological oxidation treatment of phenolic effluent at coke oven by-products plants

- improved sludge handling at various clarifier units - improvement of oil catching and separation units - recovery of water from ash dump ponds - adoption of filter presses instead of tailing ponds for washing plants at mines

For noise pollution:

- stoppage of all steam and compressed air leakages - silencers at blast bypass in blast furnaces and steam blow off valves at boilers,

purging silencers at oxygen plants, etc. - noise deadening surface on skids of finishing bay of mills to minimize noise during

product handling - enclosures for all pumps and compressors

In the area of solid wastes management:

- Solid wastes considered as solid by-products (considered as a profit making area) - granulation of all blast furnace slag for cement making - large scale utilization of granulated blast furnace slag, slag ballast, BOF slag and fly

ash in specific proportion for heavy duty road making in place of cement concrete. This has been successfully utilized in other countries

- recycling BOF slag to blast furnace Modernization schemes in energy efficiency and pollution abatement technologies

Three of the major steel plants at Durgapur, Rourkela and Burnpur are undergoing technological upgrading. Apart from this, major investments are proposed for continuous casting facilities at Bokaro and expansion of capacities at Salem Steel Plant. In conceiving these schemes, special care has been taken to incorporate state-of-the-art pollution control equipment wherever necessary. The total expenditure for these modernization schemes would be approximately Rs. 12,300 Billion out of which Rs. 490 Billion will be invested in pollution control (Table 6.2.14).

Table 6.2.14 Expenditures for modernization schemes in India’s iron & steel industry

for energy efficient and pollution abatement technologies

Technology Total Cost (Billion Rs)

Estimated Cost for Pollution Control

(Billion Rs) DSP Modernization 2667.00 212.61 RSP Modernization 2561.00 122.22 IISCO Modernization 5084.00 176.41 BLS Continuous Casting 1600.00 71.52


SSP Expansion 69.37 0.80 SSP Hot Rolling Facilities 425.00 6.97 Total 12306.97 590.53

The modernization and expansion schemes include pollution control measures at the new plants being installed. For the existing plants, various recommendations made were being taken up under the on-going Additions/Modifications/Replacement (AMR) schemes. About 54 such schemes (each costing more than Rs 1 billion) were under implementation at the major plants, at a total cost of Rs 137 billion. These schemes were scheduled to be completed by 1993. Another 41 schemes costing approximately Rs 250 billion were planned (Table 6.2.15).

Table 6.2.15 Projects to be completed under additions/modifications/replacement scheme

Project Plant Site Under Implementation Envisaged Number of

Units Cost (106 Rs) Number of

Units Cost (106 Rs)

Bhilai 20 45.85 8 111.84 Durgapur 13 12.48 16 31.76 Rourkela 9 10.19 7 70.95 Bokaro 7 67.42 10 36.84 IISCO 1 1.23 - - Total 50 137.17 41 251.39 In addition to the above, a large number of smaller value schemes are under implementation. The assessment of revamping/ modification requirements for pollution control equipment is being done on a continuous basis. 6.2.6 Status of Application of New Technologies

Listed below in Table 6.2.16 are the pollution abatement technologies to be adopted in the future plants being introduced into the integrated steel industry of India.

Table 6.2.16 Future centers for pollution abatement in Indian integrated steel mills

Plant Technology Adopted Bhilai New de-dusting systems at the rotary kilns Gas cleaning plant for open hearth furnace 7,8,9 New ESP for boiler # 6 at power plant 1 Replacing existing scrubbers by ESPs for boilers # 1 to 5 at power plant

1 Cast house slag granulation at blast furnace # 5 Durgapur Dust suppression at existing ore handling plant


Dust extraction from bin top at blast furnace complex New de-dusting system for dolomite rotary kiln Cast house slag granulation at blast furnace # 4 New DCDA sulfuric acid plant Rourkela Complete de-dusting system at coke screening plant New bag filter for dolomite brick plant New gas cleaning plant for existing BOF in steel making shop Alkali scrubbing in fertilizer plant to further bring down NOX emission BOD plant for treating coke oven effluent Bokaro Complete revamping of de-dusting systems at coal & ore handling plants New de-dusting system for coke sorting plant New DCDA sulfuric acid plant replacing SCSA process to reduce SOX

emission New ESP for sinter plant Revamping of all ESPs for lime & dolomite kilns BOD plant for treating coke oven effluent IISCO New DCDA sulfuric acid plant replacing SCSA process to reduce SOX Water recycling from pig casting machine All Plants Hydrojet cleaning for coke oven doors Silencers for snort valve at blast furnaces and bypass valves at power

plants Mobile industrial vacuum cleaners for improved housekeeping Nowadays, there is an increasing large scale adoption of air pollution abatement and water pollution prevention measures in the integrated steel plants in India. Effluent quantities have been contained within the norms stipulated by the regulatory agencies. Suspended solids, phenol, oil & grease, cyanide are being monitored on a quarterly basis and are found to be very much within the norms after 1990. Over the years of adopting pollution abatement technologies, a number of improvements have been realized, which are graphically shown in the following figures for water effluent quality. Reducing fresh make-up water is one of the major exercises carried out by the Indian iron & steel industry. Efforts were made to recirculate water and reduce fresh make-up water requirement as well as discharge. The trend in consumption of fresh make-up water requirement which was around 50 m3 per ton of steel in 1987-88 has come down to around 10 - 12 m3 per ton of crude steel, thus very well meeting the requirement (Figure 6.2.4).

Suspended particulates concentration in milligrams per cubic meter have also reduced from 600 mg/m3 in the year 1987-88 to 300 mg/m3 in 1992. This level has satisfied regulations on suspended particulates. Suspended solid concentration has decreased to a great extent after the installation of abatement plants and technologies (Figure 6.2.5).


Country Report: Philippines

6.3.1 Introduction

The steel industries of the industrialized nations have mature markets for steel and are responding to the need for rationalization in their production. In the developing world, the steel industry is emerging as a growth sector as national economies develop significant levels of demand. This is particularly true for South East Asia, which is expected to be one of the few growing markets for steel during the 1990s. Demand in the Asian region continues to grow at a very uneven pace, a problem which is exacerbated by the high levels of fluctuation in recent demands from China. Asian steel consumption has grown faster than its capacity to produce as is illustrated in Table 6.3.1.

Table 6.3.1. Asian steel data (excluding Japan, PR China & Korea)

1982 1992 Mt % Mt %

World Production 645 100 721 100 Asian Production 29 4.5 65 9.0 Asian Consumption

42 6.5 87 12.0

The prime need in the case of the iron and steel industry in Asia is to satisfy the demand for steel and establish adequate production capabilities. Table 6.3.2 gives the historical Apparent Domestic Consumption (ADC) of finished steel for the year 1991 in selected countries.

Table 6.3.2. Apparent domestic consumption of steel products in 1991 (Mt)

Country Long Products % Flat Products % Total Australia 2.4 59 1.7 41 4.1 China 20 36 35 64 55 Indonesia 1.9 50 1.9 50 3.8 Japan 52 55 42 45 94 Korea 15 56 11.8 44 26.8 Malaysia 1.6 48 1.7 41 4.1 Philippines 0.8 50 0.8 50 3.8 Singapore 1.3 52 1.2 48 2.5 Taiwan 7.6 46 8.9 54 16.5 Thailand 2.5 45 3.1 55 5.6 Vietnam - - 0.25 100 0.25 TOTAL 105.1 49 108.4 51 213.5

Source: Beddows and Company, 1993.


Almost all sectors of the economy are beneficiaries of the iron and steel industry. The biggest local consumers of iron and steel products are the construction, industrial, shipbuilding, appliances and automotive industries. 6.3.2 Technological trajectory of the Philippine steel industry

6.3.2.1 Capacity

The Philippine iron and steel industry has evolved into one of the most significant growth industries in the country. There are about 60 local firms involved in the making of iron and steel products, 80% of which are located in Metro Manila. The National Steel Corporation which is the dominant firm in the sub-sector is the only domestic producer of flat-rolled steel, and has the biggest rated capacity for steel melting. The shortfall in NSC’s ability to supply the market with flat rolled products is made up by imports. Imported steel is primarily brought into the country by major trading houses and then distributed either through service centers or end-users themselves. Table 6.3.3 illustrates the supply structure of the local iron and steel products from 1966 to 1986. Table 6.3.3. Supply structure of iron and steel products in the Philippines (in tons)

Year Importation % Share Production % Share Total Supply

1966 312723 46 390931 54 683454 1967 411948 49 430702 51 842650 1968 360258 44 451404 56 811662 1969 328892 39 519602 61 646494 1970 254366 31 573744 69 828110 1971 223329 28 540596 71 763925 1972 242040 30 461443 66 703483 1973 245509 29 592655 71 838164 1974 266893 34 513221 66 780114 1975 293618 31 663755 69 957373 1976 315620 31 709610 69 1025230 1977 309921 28 769760 71 1079681 1978 418663 32 877287 68 1295950 1979 441137 33 900065 67 1341202 1980 855722 45 1050712 55 1906484 1981 760313 44 960955 56 1721268 1982 1164513 47 1339174 53 2503687 1983 1184881 46 1418613 54 2603494 1984 553828 28 1441614 72 1995442 1985 385591 19 1664657 81 2050248 1986 635459 30 1498736 70 2134195

Source: MIRDC, various years.


Apparent domestic consumption of iron and steel products ranged from 1.7 to 2.1 million metric tons per year from 1981 to 1986, based on a study conducted by the Metal Industry Research and Development Center (MIRDC). From 1980 to 1986, an average of 63% domestic requirements for iron and steel products was met by local production. A significant 37% of the demand was supplied by imports. In 1984, the share of demand met by local production increased to 72%. This shift was however due to an importation ban imposed by the government as a result of the country’s foreign exchange difficulties. In 1989, there were 12 companies with electric steel melting facilities which produced billets and ingots. Their total rated capacity was estimated at 718,000 tons a year. The capacities of two companies account for 50% of the total: They are NSC and Armco-Marsteel Alloy Corporation with annual melting capacities of 300,000 and 60,000 tons, respectively. All 12 companies use electric-arc furnaces (EAFs) to produce crude steel from steel scrap. The nominal capacities of these EAFs range from 8 to 45 tons. EAFs are prevalent in the sub-sector because they require much smaller investments compared to a blast furnace. In addition, electric arc furnaces are more flexible with respect to the kind of product output. There are about 33 steel rolling mills in the country, with total annual rated production capacities for bars and rods estimated at 1,086,390 tons. The annual rated production capacity per company ranges from 1,200 to 160,000 tons. There are 11 major GI sheet manufacturers. The total rated capacity of these firms for galvanizing and color bonding is estimated at 451,000 tons per year. The annual rated capacity per company ranges from 18,000 to 100,000 tons. Two types of galvanizing equipment are currently being used by local GI sheet manufacturers. These are the semi-continuous type and the batch type. There are 13 Pipe manufacturers, having a total annual rated capacity of 407,850 tons. Generally, the major facilities of pipe and tube mills are grouped into the forming section, galvanizing section, straightening and cutting section, and threading and finishing section. At the start of the 1990s, steel demand was placed at 1.7 million metric tons with crude steel production estimated at 520,000 tons, mainly coming from recycled scrap. At present, there are 17 steel melting facilities with only 14 plants in operation. The total installed capacity is 1,086,000 tons with an estimated operating capacity of 928,000 tons. 6.3.2.2 Product mix

For the melting and bar & rod rolling, the estimated average consumption of scrap per metric ton of liquid steel is 1,160 kg, yielding an input-output ratio of 1.16:1. Local scrap comes from two major sources: (1) companies which own home scrap, and (2) industrial and obsolete scrap. Home scrap comes from croppings of ingots, billets and other rolled products; clippings from plates and sheets; and defective products. Steel mills are estimated to supply 6 to 30% of scrap used. Industrial scrap is the iron waste from the fabrication of iron and steel products whereas obsolete scrap comes from demolished buildings and worn-out equipment, machinery and automobiles.


Table 6.3.4. Melting facilities in the steelmaking industry of the Philippines, 1992 (Total operating capacity: 928,000 tons/year)

Company Annual capacity

(103 t/year)

Furnace capacity

(tons)

Furnace transformer

rating (MVA*)

Remarks

National Steel 350 45 26.0 with oxy-fuel burner

45 26.0 Armco Marsteel 67 25 12.0 Metro Concast 50 25 9.5 Apollo Steel 40 15 7.5 with Cupola

melting Cathay Pacific -Novaliches plant 45 15 7.5 -Cainta plant 75 25 18.0 Armstrong 20 10 4.5 with expansion Allied Integrated 40 12 0.5 1 furnace operating 12 7.5 Osaka Steel 25 10 7.5 Elegant Steel 40 15 10.0 Master Steel 8 5 0.5 induction furnace Union Steel 8 5 2.0 Globe Steel 50 15 7.5 shutdown but may 10 7.5 soon be operated Marcelo Steel 48 8 2.5 shutdown 10 5.0 12 7.5 Milwaukee 80 30 18.0 SKK 1 40 25 12.0 2 40 25 12.0 PISCOR 60 40 open hearth

furnace not yet in operation

Total 1086 * mega volts-ampere


Source: Philippine Iron and Steel Industry, 1992. In 1986, imports of scrap totaled 85,243 tons valued at US$ 7.6 million, giving an average price of US$89 per tons. Most of the scrap imports were from the United States and the United Kingdom. According to the MIRDC study, the average electrode consumption per tons of liquid steel is 7.5 kg. The carbon electrode requirements of the sub-sector are met mainly by imports. The most common ferro-alloys used by steel plants are ferro-manganese, ferro-silicon, ferro-chrome, and silicon-manganese. It is estimated that the average consumption of ferro-manganese and ferro-silicon is 6 kg each per ton of liquid steel. Silicon-manganese usage averages 5 kg per ton, and ferro-chrome usage 7 kg. In 1986, two local producers of ferro-alloys sold about 1,900 tons of ferro-alloys at an average price of P12,230 per ton. Imports during the year totaled 1,723 tons at an average price per ton of US$655. The ferro-alloys were imported mostly from the Netherlands, the United Kingdom and Taiwan. Imports of billets/ingots and slabs totaled 391,367 tons in 1986 at an average price of US$1,097 per ton. The NSC’s prices for locally produced billets and ingots, on the other hand, averaged P14,126 per ton during the same year. Domestic sales of billets in 1986 totaled 153,931 tons. Cold and hot-rolled products are supplied locally by NSC. In 1986, the average price of domestic cold and hot-rolled products was P11,573 and P10,541 per ton, respectively, while imported cold/hot-rolled hoops and strips was US$773 per ton. Almost 80% of these products were imported from Japan.

6.3.2.3 Current position in the national economy

With the establishment of a democratic government in 1987, GDP grew at a healthy 5.5% from 1987 to 1989. Since 1989, a series of setbacks have hit the Philippine economy, causing the economic growth to slow considerably in 1990 to a rate of 2.4%. Severe droughts in 1991 led to massive power outages and caused a 1% contraction in the economy. The volatility of the Philippine economy as a whole has been mirrored by the steel-consuming sectors as well. The demand for steel increased by 15% from 1988 - 1989 but then contracted 5% from 1980 - 1990. Steel demand contracted a further 8% from 1990 - 1991 before experiencing an explosive 27% rise from 1991 to 1992. In 1992, the iron and steel industry’s output represented 10.4% of the total manufacturing output. It however accounts for 7.6% of the whole industrial sector. A share of about 2.5% of the GDP and GNP was noted in 1992. This is summarized in Table 6.3.5.


Table 6.3.5 Contribution of the iron and steel industry to the national economy Year 1981 1982 1987 1988 1989 1990 1991 1992

Value of Output 4058 3320 14550 19762 25302 29407 32011 33935Manufacturing 71829 79608 169627 204784 230163 267485 315938 327501

Percentage (Manufacturing)

5.65 4.17 8.58 9.65 10.99 10.99 10.13 10.36

Industry Sector 110309 123154 235094 280957 322964 371347 424504 446334Percentage (Industry)

3.68 2.70 6.19 7.03 7.83 7.92 7.54 7.60

GDP 281596 317177 682764 799182 925444 1073098 1244741 1338421Percentage (GDP)

1.44 1.05 2.13 2.47 2.73 2.74 2.57 2.53

GNP 280543 313544 670826 791822 914126 1078408 1262358 1370379Percentage

(GNP) 1.45 1.06 2.17 2.50 2.77 2.73 2.54 2.48

Source: Philippine Statistical Yearbook, 1993 6.3.3 Evolution of energy efficiency with technological changes

The iron and steel sub-sector is one of the biggest users of energy in the country. The Philippine Steelmakers Association estimates that in 1985 at about 45% capacity utilization, the primary and secondary iron and steel processing sub-sector consumed 220 million kWh of electricity and 23 million liters of fuel, mainly fuel oil. The Association likewise estimates that the sub-sector has the biggest consumption of electricity in Metro Manila as compared to other sectors in the area. The average monthly consumption of the iron and steel sub-sector nationwide was placed at 12 million kWh. In 1990, the industry consumed about 789 million kWh of electricity or about 3% of the country’s total electricity consumption (see Table 6.3.6).

Table 6.3.6 Electricity consumption of the Philippine iron and steel industry (106

kWh) Year 1974 1979 1981 1982 1988 1989 1990 1991 1992Iron & Steel*(I&S)

227 360 568 437 988 1369 790 848 1248

Industrial Sector**

7597 7769 8566 9763 8982 9339 9060

I&S percentage 7.48 5.62 11.53 14.02 8.80 9.08 13.77National Total ** 8356 12060 18583 19406 24539 25573 25215 2564

9 2568

2I&S percentage 2.72 2.99 3.06 2.25 4.02 5.35 3.13 3.30 4.86


Source: * National Statistics Office; ** Department of Energy, 1990. Based on the assessment conducted by the Waste Reduction Assessment (WRA) team of the ASEAN Environmental Improvement Project in 1993, wherein five iron and steel companies in the Philippines were considered, the following gives the electricity consumption breakdown (source: Raytheon Engineers & Constructors, 1994):

Lighting 2.50% Air conditioning 2.25% Process (motors, furnaces, etc.) 95.25%

Since the process consumes most of the energy, conservation effort should start in this area. The following were identified as some of the causes of inefficiency:

- Combustion systems: very few companies have controlled combustion processes. They do not know exactly how efficiently they are burning fuel. In cases like these, there is good probability that combustion is occurring either with too much excess air or with deficient air. In both cases, energy is being wasted.

• Cracks and small opening were seen in some small, low pressure boilers where air can infiltrate into the furnaces causing combustion to occur with much excess air.

• In some storage for the solid fuel, coke is not provided with cover, thereby

exposing the fuel to rainwater thereby increasing its moisture content.

- Steam Systems: excess steam is generated by the waste heat boilers which is often brought about by some process changes.

• Un-insulated steam and condensate pipelines, valves and fittings. • Most steam systems drain condensate to the sewer line, thereby wasting water,

chemicals and energy. • Steam-heated acid and chemical baths were observed to be overflowing. • Steam leaks are also common especially on the valves’ and fittings’ connections. • In steam transmission system, heat is usually lost in connective-radiant heat loss

from un-insulated pipes, valves, fittings, and steam leaks.

- Motor Drive Systems: over motoring


6.3.4 Environmental externalities of technological development in the Philippine iron and steel industry

The type and volume of pollutants produced by firms in the iron and steel sub-sector vary according to the processes used. The electric furnaces used in steel melting generate particulate emissions and carbon monoxide. These are removed through the use of glass cleaners. Rolling mills burn fuel which can emit sulfur oxides into the atmosphere. The use of desulfurized fuel will reduce this form of pollution. Fluxing agents used in galvanizing, such as ammonium chloride and zinc ammonium chloride, generate air contaminants. These can be removed using electrostatic precipitators, wet scrubbers, or fabric filters. The installation, operation, and maintenance of anti-pollution devices entail additional costs for firms in the sub-sector. However, strict government policies on industrial pollution, implemented through the National Pollution Control Commission, have led to a widespread use of anti-pollution devices by firms in the sub-sector. Wastewater

Wastewater flow diagrams are not available in most facilities. The wastewater flow rates are not always available and are often estimated. Moreover, too many wastewater streams are allowed to pass to the receiving body of water without adequate treatment. The chemical constituents of the untreated streams are not generally known. Solid wastes

The major solid waste streams generated by the iron and steel industry include the following:

1. slag from the EAF and Cupola furnace operations 2. iron scales from casting and rolling operations, removed from scale pits 3. iron fines and chips generated from cleaning and machining/grinding during metal

finishing operations 4. collected/captured dusts from dust filtration systems as previously emitted from

EAF and Cupola furnace operations 5. water-scrubbed dusts previously emitted from furnace operations, removed from

settling pits 6. water-scrubbed dusts previously generated from blasting/cleaning operations in the

foundry, removed from settling pits 7. sludges from water treatment plants (WTP) 8. sludges from wastewater treatment plants (WWTP) 9. plating sludges from the electrolytic tinning lines 10. skimmed paint mist from collecting water basin; the paint mist previously generated

from spray painting and coating during metal finishing operations 11. sand wastes from foundry operations 12. waste/spent refractory materials from furnace operations 13. waste/spent flux material (ammonium chloride) from galvanizing operations


14. zinc dross from galvanizing operations Except for waste streams # 4 - 10, the above solid waste streams are considered first generation wastes as these are directly derived from the process. The others are considered second-generation wastes since these have undergone a waste treatment process before being generated as a solid waste stream, such as the captured dusts collection systems, and the sludges from the wastewater treatment plants. The solid waste materials generated by the Philippine iron and steel industry can be classified as hazardous or non-hazardous. Currently, there are two ways of determining whether a solid waste stream is hazardous or not. One, a solid waste stream is considered hazardous if it is explicitly listed in the Implementing Rules and Regulations of Republic Act 6969. Two, a solid waste stream is considered hazardous if it exhibits at least one of four hazardous characteristics such as corrosivity, reactivity, ignitability, or toxicity, which are established after the solid waste materials have been subjected to standard laboratory tests. The hazardous solid waste materials of the iron and steel industry include the following:

1. Electric arc furnace and Cupola furnace dusts. Because of the presence of heavy metal contaminants and the possibility of leaching of the environment, the furnace dusts are considered toxic and thus hazardous. Heavy metals found in furnace dusts with established toxicity include lead, chromium, cadmium, and to some extent, mercury.

2. Sludges from wastewater treatment plants. Normally, chromium is significantly present, and proved leachable.

3. Skimmed paint mist. This is explicitly listed as hazardous under the implementing rules and regulations of Republic Act 6969. The paint mist can also contain lead.

4. Spent ammonium chloride flux material, listed as hazardous (inorganic chemical wastes) under RA 6969.

5. Zinc dross (with lead), listed as hazardous (inorganic chemical wastes) under RA 6969.

Table 6.3.7 indicates available figures on the quantity of solid waste generated per unit of production in a specific operation. 6.3.5 Potential for energy efficiency improvement and pollution abatement through


6.3.5.1 Energy efficiency

Some of the process areas where improvements can be realized are as follows: Scrap pre-heating

The temperature of the fumes from the electric arc furnace is at about 1200oC, and this can be used to preheat scrap metals before feeding these to the furnace.


Table 6.3.7 Iron and steel industry operations and solid wastes generation

Operation Solid Waste Quantity Melting (in the EAF) filtered dusts 24 kg per ton of molten metal slag 81-100 kg per ton of molten metalMelting (in the Cupola furnace) scrubbed dusts 2.14 liters per ton of molten metal slag 0.43 m3 per ton of molten metal Continuous Casting slag 1.74 kg per ton of cast metal Hot Rolling scales 7.22-7.5 kg per ton of rolled metalCold Rolling mill scales 14.8 kg per ton rolled metal Galvanizing zinc dross 536 kg per ton galvanized iron Wastewater Treatment Plant sludge 15.5 grams per m3 effluent

Source: Raytheon Engineers & Constructors, 1994. Combustion control

Combustion control involves the measurement of parameters which describe the state of efficiency of combustion, analysis of data to adjust the combustion process parameters which cause the inefficiency in combustion or heat transfer, and the automatic or manual adjustment of parameter values through hardware components. Consistency in achieving optimum combustion is attainable only if it is properly controlled. Motor drives optimization

Motor drive systems may consume as much as 50 to 60% or even more of the total electricity used by the industry. Any conservation program, therefore, for controlling electrical energy cost should consider replacing existing standard motors with more energy efficient models. The size of the motor should match its load. Before considering a replacement, however, good management practice demands a thorough economic analysis to justify the significant cost of retrofitting. Cogeneration

Cogeneration is the simultaneous production of electric power and any useful thermal energy from a single energy source. A thermal power plant generally produces electricity with an energy efficiency of about 34%. With the use of cogeneration, the overall energy efficiency of the system can be as high as 64% or more. There are two general approaches to cogeneration, one by the use of a topping cycle, the other by the use of a bottoming cycle. The topping cycle consists of generating first the electric power and then using the exhausts as thermal energy. The bottoming cycle consists of first using the fuel for the process (e.g. steel furnace, aluminum melting furnace or any high-temperature process equipment) and then using the high temperature waste heat to generate electricity.


Power factor correction

The power factor is the relationship (phase) of current and voltage in an AC electrical system. Under ideal conditions, current and voltage are “in phase” and the power factor is 100%. If inductive loads are present, power factor of less than 100% will occur. One of the common methods of correcting power factors is by installing capacitor banks on the primary or secondary side of the plant power transformer. If electric bill penalties are the only concern, the total capacitor requirement can be installed in one bank on the load side of the metering equipment. The system requires elaborate switching devices to prevent leading power factors during low loads. Capacitors can be installed at load centers, usually motor control centers and switched according to the loads. This method increases the load capabilities of the plant electrical distribution system. The power factor is corrected at the load center and back through the distribution system. Better voltage regulation is obtained for the system’s transformers. Engineering is simplified and costs of installation are reasonable. Capacitors can be connected directly across the terminals of larger motors thereby eliminating the cost of separate switches. This method requires more capacitor units and generally higher installation costs. The power factor is corrected at the motor and back through the distribution system. Energy efficient lighting

The percentage of lighting electrical power in plants is estimated at 2.5%, which is nearly 13 million kWh/year. In all probability, the amount of lumens generated by these millions of kWh may be more than what is optimally needed. Evaluating and redesigning the existing lighting installations with energy efficient luminaires and lamps should be undertaken. Energy use in lighting is a function not only of design and luminaires but also of operating hours and operating modes. Lighting controls may be used to reduce energy in response to availability of daylight, cleaning practices, lighting maintenance systems and the occupancy schedule of the lighted space. 6.3.5.2 Pollution abatement

EAF dust treatment processes

Electric arc furnace melting of steel scrap and briquetted iron generate an estimated 15,000 metric tons per year of EAF dust containing significant amounts of hazardous metals such as chromium, lead, cadmium, and zinc (15%). This waste product is commonly dumped without prior treatment (except pelletizing) on site as reclamation material. Current practices in Taiwan, Japan, Korea, and the U.S. are based on rendering the waste constituents insoluble through chemical or physical means. Solidification, stabilization, vitrification, encapsulation, and fixation are techniques characteristically employed by companies, and on the basis of end results, they may be considered generic variants. These


practices involve locking the constituents in a mix that is structurally sound and chemically alert. Fixation treatment in the Philippines has employed cement as a binder. Other materials such as pozzolana, diatomaceous earth, slag, ground bricks, and other materials containing hydrous silica may also be used. The use of cleaner scrap in the furnace charging mix has the potential of reducing the volume and toxicity of the dusts generated from the furnace operations. This would require an improved inspection and classification procedure of scraps that are currently from varied and numerous suppliers. The existing waste load on the landfill on-site can be reduced if the slag wastes can be utilized as a by-product. Currently, the slag wastes constitute a large fraction of the solid waste burden. Although sea reclamation has been practiced when available, with no apparent and significant opposition, this should not be taken as something permanent. The environmental impact of sea reclamation is not fully understood and may be unacceptable in the future. In which case, the consequent on-site landfilling may compete on limited land, that would have been used otherwise for future expansion or other productive purposes. The segregation of the hazardous from the non-hazardous waste streams can lead to a lower quantity of hazardous waste generated, which will require safe handling and disposal. Currently, some facilities are mixing their hazardous and non-hazardous waste streams. The use of more cast iron scrap materials (engine blocks and machinery parts) rather than steel scraps has potential in foundry operations. The advantages are two-fold: the cast iron material is easier to melt and is also cleaner compared to tin-coated steel scraps. Investigating alternatives to spray painting in metal finishing operations, such as paint-dipping, can be done. Metal recovery in the WWTP sludges such as for tin, which is present in significant levels, up to 20% by weight, and possible use within the process, is possible. The residual sludge for final disposal will also be reduced.

6.3.5.3 Managerial improvement

The companies have the policy of operating their plants with minimum wastes and emission to the environment. They have policy pronouncements and guidelines related to the environment on various areas of their operations. Some of the guidelines are in written memoranda (e.g. on the economical use of electricity) but many have been communicated only verbally to employees concerned. The companies implement their corporate environmental policies by incorporating them in business plans, with top management providing leadership in implementing the policies.


Most of the companies have installed the following systems: (1) environmental; (2) risk management; (3) safety management, and (4) emergency preparedness. The latter covers power failures, fires, strikes, floods, earthquakes, and typhoons, but the systems require complete documentation and integration. Risk management, as in most companies in the Philippines, is just focused on purchasing insurance. 6.3.6 Status of application of new technologies for pollution abatement

The following are the present industry practices in the Philippines for the management of hazardous solid waste materials from iron and steel operations:

- The furnace dusts emitted from melting operations are captured by either dust collecting filters or are scrubbed with water. The captured dusts are removed from the filters (dry condition), or from settling basins (wet condition) and are then transported to a land area on-site where they are stockpiled and eventually landfilled. If there is available land on-site, the landfilling is done on-site; otherwise, the stockpiled solid materials are brought for landfilling off-site.

- The WWTP sludges are removed occasionally, normally during shutdowns or when

the collecting basin is near capacity. The sludges are then either stock-piled on-site (contained in drums or in the open) for off-site landfilling. For sludges derived from WWTPs serving galvanizing operations, the sludges are placed in drums and await transfer to designated cement plants. When there are no trips available, or when there are no specific requirements from the cement plants, the WWTP sludge is disposed in a landfill, either on-site or off-site.

- The skimmed paint mist from metal finishing operations are either collected

together with municipal wastes for disposal off-site, or buried on-site. - The spent ammonium chloride flux material and the zinc dross from galvanizing

operations are normally sold to outside buyers and users. While awaiting pick-up, the solid waste materials are temporarily stockpiled on-site.

- The plating wastes from tinning lines are normally sold to outside buyers.

In case of the non-hazardous solid waste materials generated from iron and steel operations, the following are observed to be the present practice in the Philippines:

- The EAF slag is removed after every melt, allowed to cool near the furnace area, then transported to a landfill on-site. In some cases, the slag material is used to reclaim the nearby sea if the facility happens to be situated in a coastal area. There has also been limited experience in using the slag material as pavement and road base material.


- The mill scales are removed occasionally from the mill scale pits, then transported to the landfill or disposal area normally on-site.

- The foundry slag waste and its residual used sand materials are also collected,

hauled and disposed at the landfill on-site. - Waste refractory materials from furnace operations are partly sold; those remaining

are stockpiled on-site and landfilled. - The iron chips from foundry operations are either sold or recycled within the

process line for low quality castings. - The scrubbed and settled dusts from the blasting and cleaning operations in the

foundry are either recycled or landfilled. 6.3.7 Conclusions

The present administration passed Republic Act No. 7103 - the Iron and Steel Act, where it defines the scope of the backward integration and provides incentives toward the establishment of an integrated steel mill. Two proponents have put forward their project proposals - National Steel with a two million ton per year blast furnace, and the Jacinto group, which engaged Shougang Corporation of China for the feasibility study of an initial one million ton per year blast furnace. The companies’ research and development activities related to the environment are still limited, though all have continuing programs on improving their use of raw materials, improving the operation of their production processes, improving their products, controlling waste emissions , and general housekeeping. On raw materials, two companies maintain a program of looking for substitutes. Some companies conduct formal waste minimization audits and general housekeeping improvement reviews. Others perform continuing research on waste reduction (e.g. recycling of cast iron chip and the re-use of dust). Some have adopted the “five S” program which includes waste segregation and disposal. 6.4 Country Report: Sri Lanka

6.4.1 Introduction

The iron and steel industry in Sri Lanka had been introduced a few decades ago when the Steel Corporation in Oruwala was established in 1961 under the Corporation Act. This Corporation was run basically as a monopoly till the end of 1980, when private investors started getting involved. By now, a few private investors are also involved in this sector. However, about 85% of the local demand is still met by the state owned Steel Corporation. The machinery and the technologies are generally old. Though it has been realized that improvement in energy efficiency and environmental standards are very desirable, the lack of finance has impeded this development.


6.4.2 Technological trajectory of Sri Lankan iron and steel industry

6.4.2.1 Capacity and production

The steel industry in Sri Lanka consists of one mill with an installed rolling capacity of 96000 tons of steel per annum and four smaller mills each with a rolling capacity of about 8000 tons of steel per annum. The larger mill which is state owned, was commissioned in 1962. The rolling output of Sri Lanka’s iron and steel industry is shown in Figure 6.4.1. The reported productivity in Sri Lanka’s steel industry is shown in Figure 6.4.2.

State-Owned

Private Sector

010203040506070

1960 1970 1980 1990 1992

Year

Pro

duct

ion

Figure 6.4.1 Rolling output of Sri Lanka’s iron & steel industry ( in 103 tons per year)

6.4.2.2 Product mix, process mix and capacity utilization

In 1962, at the commencement, the first mill was provided only with the facility of rolling steel from imported billets. Subsequently an EAF was installed to use scrap steel available in the country. At the time of commissioning the EAF, the price of electricity was very low, as most of the electrical energy at that time was generated from already depreciated hydro power plants. With the commissioning of new hydro and thermal power plants the cost of electricity has escalated very much, resulting in the closure of the EAF.


Year

ton

per e

mpl

oyee

0

5

10

15

20

25

30

35

40

1960 1970 1980 1990 1992

Figure 6.4.2 Productivity in Sri Lanka’s steel industry (ton per employee)

Currently the steel factories have two main production lines - rolled products and wire products. In the rolled products section, the capacity utilization improved from 52% in 1985 to 55% in 1995. But the utilization ratio in the wire products section dropped from 35% to 27% over the same period. 6.4.2.3 Role of the industry in the national economy

The contribution of the steel sector to the Sri Lankan economy has been growing over the years. The total value added and the direct employment by the steel sector was as follows:

Year 1985 1993

Value Added (Million Rs.) 23.874 437.346 No. of Direct Employees 1568 1398 Sector employment as a ratio of:

Industrial EmploymentTotal Employment

0.5% 0.03%

0.18% 0.03%

Although the total value added has increased significantly from 1985 to 1993, the direct employment has declined by about 10% mainly due to redundancies. The percentage of value added to GDP increased from 0.02% in 1985 to 0.1% in 1993, representing a five-fold growth in relative terms. The value added to the steel sector as a ratio of industrial value added increased from 0.18% in 1985 to 0.72% in 1993. Despite the increasing contribution over the years, the small percentage ratios in 1993 indicate the insignificant direct contribution of the sector to the industrial and overall value added. However, steel being a direct input to many other economic activities, it remains very important in the Sri Lankan economy notwithstanding the lowly relative figures.


6.4.3 Evolution of energy efficiency in Sri Lankan iron and steel industry

The reported integrated specific energy consumption was 0.175 and 0.244 toe/ton steel in 1990 and 1992, respectively, for the mini - steel industries. The increased specific energy consumption was due to the introduction of steel manufacturing facilities in addition to those existing rolling facilities in 1992 at these mini - steel industries; otherwise it should have been constant. At the largest state owned steel mill, the integrated specific energy consumption was 0.139 and 0.086 toe/ton steel in 1990 and 1992, respectively, which shows an efficient energy consumption.

6.4.4 Environmental externalities in Sri Lankan iron and steel industry

Since Sri Lankan iron and steel industry consists of only electric arc furnaces and rolling mill facilities, the major environmental problems arise from solid waste though water and air pollution cannot be omitted. At the moment none of these factories is equipped with wastewater treatment facilities or air pollution control equipment. 6.4.5 Potential for energy efficiency improvement and pollution abatement through


The problems encountered in the state owned mill and the recommendations to resolve them are given below: Observation Recommendation Supply of billets (of 80 mm square) is unstable and not sufficient, because such billet size is not commonly available world-wide. The existing furnace is unable to achieve an effective operation due to unreasonable configuration and insufficient combustion control devices. The recuperator to preheat the combustion air utilizing the flue gas is not functioning and is beyond repair.

Modify the rolling mill plant to accommodate 120 mm square billet which is available in plenty. For this purpose, replacement of the reheating furnace and addition of a roughing mill are necessary. A new reheating furnace with high thermal efficiency will reduce the fuel consumption.

As a continuation of the privatization of state industries, the state owned steel mill will be privatized very soon. With this arrangement, it is likely that the above suggestions will be implemented soon. In respect of the steel making plant, the factors mentioned below have hindered smooth steel making operations and led to high consumption of electric power:

- redundant hours of scrap charging - insufficient scarp pre-treatment - improper scrap blending


- lack of provisions for Oxygen Lancing and Carbon Injection - low reliability and low accuracy of temperature measurements of molten steel - additive charging being done manually by opening the furnace roof - refractory life being extremely low due to unsuitable refractory lining method for

furnace bottom - lack of suction capacity of exhausting fumes from EAF has deteriorated the plant

environment The other four mills are all privately owned and have been in operation only during the last few years. A few more such small mills are being commissioned at present. Some of these mills have installed EAFs for scrap melting and are operating them successfully. It is generally believed that the state owned steel mill maintains the desirable quality of its product whereas the smaller private mills do not maintain such quality standards. Due to their lower overheads, these small mills are competing very effectively with the large steel mills despite producing inferior products.


7. BIBLIOGRAPHY Sections 1-4

Affandi, M., 1993. “Energy Modeling in the Reformer and Reduction Units in Krakatau Steel Plant”, AIT Thesis no. ET-93-17, Bangkok, Thailand. Asian Institute of Technology, 1989. “Wastewater Treatment in Selected Industries”, Division of Environmental Engineering Silver Jubilee Year 1989, Asian Institute of Technology, pp. 131 -133, 182 -187. Barnes, 1980. “Energy Conservation in the British Steel Corporation”, Energy, no.5, pp.49. Bhattacharyya, A. and Subramaniyam, B.R., 1975. “Pollution from the iron and steel industry - The Indian context”, The Institution of Engineers (India). Bisio, G., 1993. “Exergy Method for Efficient Energy Resource Use in the Steel Industry”, Energy, Vol. 18, No. 9. Biswas, A.K., 1984. “Principles of Blast Furnace Ironmaking”, SBA publication. Culhance, F.R. and Conley, C.M. 1973. “Air pollution control electric arc melting furnaces”, Industrial air pollution control, edited by Kenneth Noll and Joseph Duncan, Ann Arbor Science Publishers inc, Michigan, USA. Dung, T., 1994. “Rational Use of Energy in the Iron & Steel Industry : The Case of Vietnam”, AIT Thesis no. ET-94-21 Bangkok, Thailand. ESCAP, 1992. “Technology Planning for Industrial Pollution Control”, United Nations Economic and Social commission for Asia and the Pacific, Bangkok. Farhangi, Anoushiravan, Mckinzie, L. D. and Brosen, B. W., 1990. “Factor Affecting Cogeneration of Electricity in Indiana’s Iron and Steel Industry”, Energy Systems and Policy, Vol. 14. Ho, J. C., Chou, S.K., and Chandratilleke, T.T., 1990. “Energy Audit of a Steel Mill”, Energy, Vol. 16, No. 7. International Iron and Steel Institute, 1981. “Energy and the Steel Industry”. Kaneko, D. and Kurihara, E., 1984. “Technology and Adaptation in Mineral Processing: A review of alternative iron and steelmaking technologies”, Working paper of World Employment Programme Research, International Labour Organization, Geneva.

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Licis, I. J., 1991. “Industrial Pollution Prevention Opportunities for the 1990s”, United States Environmental Protection Agency. Marc, R., 1979. “Industrial Energy Conservation and the Steel Industries of the United State”, Physics Department, University of Michigan, USA. Matsui, S., 1992. “Industrial pollution control in Japan - A historical prospective”, Asian Productivity Organization. McGanno, H.F. (ed.), 1970. “The Making, Shaping and Treating of Steel, 9th ed.”; United States Steel Corp., Pennsylvania, U.S.A. Meunier, Y., 1984. “Energy Efficiency in the Steel Industry with Emphasis on Developing Countries”, World Bank Technical Paper no.22. Nemerow, N.L., 1978. “Industrial water pollution: origins, characteristics and treatment”, Addison-Wesley Publishing Company Inc, Reading, Massachusetts pp. 482 - 498. Nippon Kokan, K.K., 1980. “Three-Step Scrap Preheating”, New Technology and Product, Sept, pp. 21-22. Overcash, M. R., 1986. “Techniques for Industrial Pollution Prevention: A Compendium for Hazardous and Nonhazardous Waste Minimization”, Translated by Michelle L. DeHertogh, Lewis Publishers, Inc. Rao, C. S. , 1994. “Environmental Pollution Control Engineering”, Wiley Eastern Limited New Age International Limited, New Delhi. ISBN 81-224-0301-8 Satayayut, J., 1990. “Process Modeling for Energy Management in the Steel Manufacturing Industry”, AIT Thesis no. ET-90-19, Bangkok, Thailand. Schrewe, H., 1981. “Developments in Continuous Casting of Steel”, Iron Making and Steel Making, Vol. 4, No.2, pp. 85-90. Sell, N. J., 1992. “Industrial pollution control issues and techniques”, Van Nostrand reinhold, New York, pp. 114 -149. Siuka and Lemperle, 1992. “Metallurgical Process Coupled with COREX Cogeneration”, RERIC News, pp. 10. Steiner, B.A., 1973. “Particulate emission control in the steel industry”, Industrial air pollution control, edited by Kenneth Noll and Joseph Duncan, Ann Arbor Science Publishers inc, Michigan, USA.


Stoll, U., and Amin, N., 1995. “Pulp and paper industry pollution control and management”, Proceedings of the workshop on Development of Energy Efficient and Environmentally Sound Industrial Technologies in Asia, May 29 - 31, 1995, Manila, Philippine. Sven, E., 1987. “Energy Conservation of Classical and New Iron and Steel-Making Technology”, Energy, Vol. 12, no. 10/11, pp. 1153-1168. Tanty B. S., 1990. “Efficient Utilization of Fuels in the Iron and Steel Industry”, AIT Thesis no. ET-90-12, Bangkok, Thailand. Thring , M.W. , 1957. “Grit Dust Fume and Gaseous Pollutants from the Iron and Steel Industry”, Air Pollution, Butterworths Scientific Publications, London. UNEP, 1994. “Cleaner production”, Industry and Environment, Vol 17 No 4, October - December 1994. USEPA, 1991. “ Pollution Prevention”, United States Environmental Protection Agency. United Nations, New York, 1990. “Environmental impacts assessment, Guidelines for industrial development”, ESCAP - Environmental and Development Series, Economic and Social Commission for Asia and the Pacific, Bangkok, Thailand. Visser, W. , 1977. “Water Management and Water Purification in Iron and Steel Works”, Industrial Wastewater and Wastes - 2, Main lectures presented at the second International Congress on Industrial Wastewater and Wastes Stockholm, Sweden, 4 - 7 February 1975, Edited by Goransson, B., Pergamon Press, Oxford. Welburn, R.W., 1985. “Product Specification Requirements for Engineering Steels”, Iron Making and Steel Making, Vol. 12, No.3, pp. 136-142. World Bank, 1995. “Industrial Pollution Prevention & Abatement Handbook”, The World Bank Environment Department in collaboration with United Nations Industrial Development Organization and United Nations Environment Program, Preliminary Version. Section 5

Energy Efficiency Division, 1995, “Technological Trajectory, Energy Efficiency and Environmental Externalities of the Iron & Steel Industry in the Philippines”, Department of Energy, Philippines, Paper presented in the Second SAREC Regional Workshop in Manila, Philippines, 29 & 30 May, 1995.

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The Asian Institute of Technology (AIT) is an autonomous international academic institution located in Bangkok, Thailand. It’s main mission is the promotion of technological changes and their management for sustainable development in the Asia-Pacific region through high-level education, research and outreach activities which integrate technology, planning and management. AIT carried out this Asian Regional Research Programme in Energy, Environment and Climate (ARRPEEC), with the support of the Swedish International Development Cooperation Agency (Sida). One of the projects under this program concerns the Development of Energy Efficient and Environmentally Sound Industrial Technologies in Asia. The objective of this specific project is to enhance the synergy among selected developing countries in their efforts to adopt and propagate energy efficient and environmentally sound technologies. The industrial sub-sectors identified for in-depth analysis are iron & steel, cement, and pulp & paper. The project involves active participation of experts from collaborating institutes from four Asian countries, namely China, India, the Philippines, and Sri Lanka. The technological trajectories, energy efficiency and environmental externalities of the iron and steel industry in the four Asian countries are presented in this document (Volume II). Other related publications based on this research finding include: Volume I Technology, Energy Efficiency and Environmental Externalities in

the Cement Industry Volume III Technology, Energy Efficiency and Environmental Externalities in

the Pulp & Paper Industry Volume IV Regulatory Measures and Technological Changes in the Cement,

Iron & Steel, and Pulp & Paper Industries An assessment of the implementation of energy efficient and environmentally sound industrial technologies among the selected countries is presented in a separate “Cross-Country Comparison” Report.

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