AREPORT ON VOCATIONAL TRAINING

INOIL AND NATURAL GAS CORPORATION LIMITED

HAZIRA, SURAT

Training Period: 18/12/2015 to 18/01/2016

SUBMITTED BY, MENTOR,ARPAN SAXENA DHARMENDRA KUMAR

From,C. K. Pithawala College of Engineering and TechnologySurat.

ACKNOWLEDGEMENT

I owe my credits of this summer training to:-

Miss Sandhya Bhatt GSU/GDU

Sh. Gaurav Pandey – LPG & KRU

Sh. Ravi Kant – CFU

Sh. Dharmendra Kumar– Utility and offsite

Sh. H. M. Ray – Cogeneration plant

Sh. Abhilash Patel – DPD/CWU

Sh. R. S. Pradhan – SRU

INDEXSL.NO TITLE PAGE NO.

2. Gas Terminal & Slug Catcher 8

3. Gas Sweetening Unit 8

4. Gas Dehydration Unit 12

5. Dew Point Depression Unit 13

6. Condensate Fractionation Unit 19

7. Sulphur Recovery Unit 15

8. Liquefied Petroleum Gas Unit (LPG) 24

9. Kerosene Recovery Unit 23

11. Utility System 27

12 CO-GEN 39

13 MECHANICAL MENTINANCE 47

14 MECHANICAL COMPONENTS IN PLANT 52

PREFACE Teaching gives the knowledge of theoretical aspects of management but implementation of theory gives practical knowledge of management field. Practical Knowledge of theory is of greater important for an engineering student. I am thankful to my college, CKPCET, Surat for arranging summer training before entering into the specialization field of master. This project report is an outline of what we have learnt during our training period at Oil & Natural Gas Corporation Limited (ONGC), one of the prestigious public sector companies running with strategy values and time management. We are thankfu l to Oi l & Natura l Gas Corporation L imited for g iv ing us such a va luab le opportunity to work with them.

I am thankfu l to Oi l & Natura l Gas Corporation L imited for g iv ing me such a va luab le opportunity to work with them.

ONGC as Processing Industry: Oil and Natural Gas Corporation is a public sector petroleum company involved in wide scale exploitation of oil as well as natural gas from the Indian mainland as well as from Arabian Sea and Indian Ocean. ONGC is one among the Indian Government’s Navrathna Companies which involves the most profit making nine public sector companies and hence is one of the most profit making companies in India.

Foundation:

In August 1956, the Oil and Natural Gas commission was formed. Raised from mere directorate status to commission, it had enhanced powers. In 1959, these powers were further enhanced by converting the commission into a statutory body by an act of Indian Parliament Oil and Natural Gas Corporation Limited (ONGC) (incorporated on June 23, 1993) is an Indian Public Sector Petroleum Company. It is a fortune global 500 companies ranked 335th, and

contributes 51% of India’s crude oil production and 67% of India’s natural gas production in India. It was set up as a commission on August 14, 1956. Indian

government holds 74.14 % equity stake in this company. ONGC is one of Asia’s

largest and most active companies involved in exploration and production of oil .It is involved in exploring for and exploiting hydrocarbons in 26 sedimentary basins of India. It produces 30% of India’s crude oil requirement. It owns and operates more than 11,000 kilometers of pipelines in India. In 2010, it was ranked 18th in the Plants Top 250 Global Energy Company Rankings and is ranked 413st in the 2012 Fortune Global 500 list. It is the largest company in terms of market cap in India.

ONGC Represents India’s Energy Security

ONGC has single-handedly scripted India’s hydrocarbon saga by: Establishing 7.38 billion tons of In-place hydrocarbon reserves with more

than 300discoveries of oil and gas; in fact, 6 out of the 7 producing basins have been discovered by ONGC: out of these In-place hydrocarbons in domestic acreages, Ultimate Reserves are 2.60 Billion Metric tons (BMT) of Oil plus Oil Equivalent Gas (O+OEG).

Cumulatively produced 851 Million Metric Tonnes (MMT) of crude and 532 Billion Cubic Meters (BCM) of Natural Gas, from 111 fields.

ONGC has bagged 121 of the 235 Blocks (more than 50%) awarded in the 8 rounds of bidding, under the New Exploration Licensing Policy (NELP) of the Indian Government.

ONGC’s wholly -owned subsidiary ONGC Videsh Ltd. (OVL) is the biggest Indian multinational, with 33 Oil & Gas projects (9 of them producing) in 15 countries, i.e. Vietnam, Sudan, South Sudan, Russia, Iraq, Iran, Myanmar, Libya, Cuba, Colombia ,Nigeria, Brazil, Syria, Venezuela and Kazakhstan.

HAZIRA PLANT

INTRODUCATION TO HAZIRA GAS PROCESSING COMPLEX

Natural gas has gained increased importance in the recent past by virtue of

its usage as substitute for coal, petrol and diesel as fuel in industrial boilers and

furnaces. Natural gas being rich in propane and butane gives straight run LPG. It

has now become possible to liquefy and transport natural gas. It is available for

uses fuel in automobiles also.

Some of the gas fields in India are producing Sour Natural gas containing

poisonous Hydrogen Sulphide Gas in varying amount. Sour natural gas containing

H2S require special treatment for removal of the poisonous gas. HC Condensate

associated with Sour Natural Gas also becomes sour and gives rise to production

of sour LPG which requires additional treatment for making it sweet, marketable

and safe for use.

Hazira Gas Processing Complex is receiving sour natural gas from South

Bassein Gas Fields which is a sub sea reservoir. The gas is transported from South

Basin field to HGPC through a sub sea pipeline. The gas is received at Gas

Terminal in a Slug Catcher where gas and slug containing HC Condensate,

moisture and chemicals (like corrosion inhibitors) are separated. Gas and

associated Condensate are sent further in separate system for processing.

The sour gas processing system at Hazira Plant, consist of followings:

1. Gas Receipt Terminal

2. Gas Sweetening Unit

3. Gas Dehydration Unit

4. Dew Point Depression Unit

5. Sulphur Recovery Unit

6. Sour Condensate Processing Unit

7. Gas Based LPG Recovery Unit

8. Kerosene Recovery Unit

GAS RECEIPT TERMINAL

At the Gas Terminal after the first receiving valves the sour gas and

condensate are then routed through a set of Pressure Reduction Control System.

These control valves maintain down stream pressures at a pre set value.

(Normally set at 70 kg / cm2). In case the pressure exceeds the value, these valves

try to close and maintain the pressure. These control valves are operated

normally in automatic mode. The Gas and Condensate then passes through

cyclone separators / filters and further distributed to Slug Catchers.

Slug, catchers are having liquid holding of 11,000 cubic meters each. They

are nothing but set of parallel pipe fingers of 48 inch diameter and approximately

500 meters in length. These pipe fingers are mounted at a slope of 1:500; thus

forming separation and collection zone. The sour gas separated is taken out from

top riser pipes to Gas Sweetening Units and the sour liquid thus collected is

routed to Condensate Fractionation Units.

GAS SWEETENING UNIT

Sour Gas from slug Catcher is distributed to different GSU trains under the

pressure control and flow control. Sour gas is first preheated up to 40 – 45 Deg. C.

sour Condensate of gas from CFU also enters down stream of preheated under

flow control. The combine Sour gas passes through knock out drums and enters

the bottom of high pressure absorber column.

The Absorber is having valve type trays. The amine solution (Methyl Di

ethanol Amine of concentration 480 gm/liter) is pumped from individual trains

units tank and is injected at the desired tray of the column. The amine and gas

flow in the column is counter current. The sweet gas from the top of the column

is cooled and routed to GDU / LPG units through a knock out drum (K.O.D).

45

AB

SO

RB

ER

AMINE TANK

PUMP

SOUR GAS FROM CFU

SOUR GAS FROM S/C

RICH AMINE

SWEET GAS

60kg/cm2

35 C

H.P. ABSORPTION

The rich amine from the bottom of the column flows to medium pressure

absorber / flash drum. The flash gases go to fuel gas header. The amine then

passes to the plate heat exchanger (exchanger returns hot lean amine solution)

and enters a regenerator column where it regenerates.

REGENERATO

R

RICH AMINE

REBOILER

COOLER

REFLUX

ACID GAS

LEAN AMINE

1 kg/cm2

128 C

AMINE REGENERATION

LP STEAM

REGENERATO

R

RICH AMINE

REBOILER

COOLER

REFLUX

ACID GAS

LEAN AMINE

1 kg/cm2

128 C

AMINE REGENERATION

LP STEAM

Regenerated column is also having valve type trays with associated reflux

and reboiler arrangement. Regenerated lean amine from the bottom goes back to

the MDEA tank and is recycled in the process.

Liberated acid gas from top of the regenerator column goes to Sulphur

Recovery unit under pressure control. The acid gas mainly consists of Carbon

dioxide, Hydrogen Sulphide and some water.

GAS DEHYDRATION UNIT: Purpose of GDU:

To remove water vapors from sweet gas with the help of tri-ethylene glycol solution.

Design of GDU:

The purpose of a glycol dehydration unit is to remove water from natural gas and natural gas liquids.

When produced from a reservoir, natural gas usually contains a large amount of water and is typically completely saturated or at the water dew point. This water can cause several problems for downstream processes and equipment

At low temperatures the water can either freeze in piping or, as is more commonly the case, form hydrates with CO2 and hydrocarbons (mainly methane hydrates).

Depending on composition, these hydrates can form at relatively high temperatures plugging equipment and piping.

Glycol dehydration units depress the hydrate formation point of the gas through water removal.

Without dehydration, a free water phase (liquid water) could also drop out of the natural gas as it is either cooled or the pressure is lowered through equipment and piping. This free water phase will often contain some portions of acid gas (such as H2S and CO2) and can cause corrosion.DEHYDRATION OF GLYCOLFunction of glycol dehydration unit is to remove moisture from rich glycol and convert it into lean glycol.

DEW POINT DEPRESSION UNIT: The purpose is to remove hydrocarbon condensate from the sweetened and dehydrated gas by chilling to avoid hydrate formation in long

distance H-B-J pipeline. The feed gas from GDU train is chilled to about (-) 5 deg.C in a chiller with the help of propane refrigerant in close circulation cycle. The cooled gas condensate is pumped to LPG plant for distillation. This treated gas is then sent to GAIL for onward transmission to H-B-J

39

PROPANE REFRIGERATION CYCLE

2.7 kg/cm215 kg/cm2

COMPRESSOR

CONDENSER

ACCUMULATOR

SUPER COOLER

CHILLER

0 oC 70oC

40oC

30oC

- 5oC

KOD

LIQ. PROPANE QUENCH

pipeline and partly to local consumers.

38

GAS CHILLING

COND. TO LPG

SEPARATOR

CHILLER

GAS/GAS COOLER

SWEET & DRY GAS FROM GDU

GAS TO GAIL /HBJ PIPELINE

LIQ. PROPANE FROM ACCUMULATOR

PROPANE VAP. TO COMPRESSOR

5oC

12oC

SULPHUR RECOVERY UNIT:

Acid gas from GSU regenerator is brought to Sulphur recovery Unit to

convert the poisonous Hydrogen Sulphide Gas into elemental Sulphur by liquefied

oxidation catalytic process. Acid gas coming from GSU is taken to Absorber /

Oxidizer vessel via inlet KOD under flow control which contains LOCAT solution.

Hydrogen Sulphide is oxidized to elemental Sulphur by atmospheric air in

presence of the catalyst. Carbon dioxide, Oxygen, Nitrogen, Water vapour and

traces of Hydrogen Sulphide (within the permissible limit set by Pollution Control

Board) is

19

ABSORBER / OXIDIZER

ADDITIVESARI 310 C ARI 310 MSurf actantBiochemDef oamer

SLURRY PUMP

SULPHURSLURRYTO MELTERAIR

BLOWER

ACIDGAS

LOCAT

vented to the atmosphere, LOCAT solution returns back to Oxidizer /

Absorber under pressure control and Molten Sulphur thus separated is taken to a

surge drum under level control. Molten Sulphur from surge drum is pumped by

vertical pumps to preconditioning unit for temperature conditioning with the help

if thermal fluid and the sent to Roto former. Here the Molten Sulphur is palletized

and then bagged in HDPE Bags, in the unit for final disposal (Selling in the

Market). Sulphur Recovery Unit has been installed as an environmental protection

unit only.

10

CW

KOHARI 600ARI350ARI310CARI400

LOCAT RETURN

MELTER

SEP

ERA

TO

R

SURGE DRUM

MOLTEN SULPHUR

ROTOFORMERBLOWERACID GAS FROM GSU

ACID GAS KOD

SUMP

STACK AT 28 M HEIGHT

ABSORBER OXIDISER

SLURRY

KOD

COOLER

BAGGING

SRU BLOCK DIAGRAM

11

Acid GasAir

Sulphur Particles

Scraper

Reduced LoCAT

Regenerated LoCAT

Center Well ( 4 Nos. )

Air Spargers

Acid Gas Spargers

Air Blast Line

Auto circulationFlow path

ABSORBER INTERNALS

12

SEPARATO

R

SURGE DRUM

MELTE

R

STEAM

MOLTEN SULPHUR

ROTOFORMER

BAGGING

FROM ABSORBER

LOCAT RETURN

MELTER / SEPARATOR

4 kg/cm2

140 oC

SOUR CONDENSATE PROCESSING UNITSour Condensate Processing Unit is Hazira Project is called as Condensate

Fractionation Unit (CFU). Associated Sour gas condensate from Slug Catcher is

preheated and taken into a condensate surge drum operating at slightly lower

pressure than incoming pressure in CFU. Condensate, Water and Gas are

separated in the surge drum. Condensate from bottom of the drum is pumped to

a stripper column through coalesce filters under flow control. In stripper column,

H2S is stripped along with lighter Hydro carbons and taken out from the column.

Liberated gas from surge drum and stripper to are jointly compressed by Off Gas

compressor and feed to Gas Sweetening train for elimination of H2S .

The liquid from stripper bottom is reboiled and feed to LPG column under

level and flow control in LPG Column LPG is taken out from the top through

Condenser reflux drum and NGL from the bottom through NGL cooler, under level

control to storage area. It is being continuously monitored that LPG coming out

from distillation column should not contain H2S more than 20 PPM. LPG thus

prod

uced from CFU is a sour LPG and the same is sweetened through processing in

Caustic Wash Unit before sending to LPG spheres.

28

STRIPER & OFF GAS COMPRESSOR

18 kg/cm2

OFF GAS TO GSU

60 kg/cm2

TO LPG COLM.

MP STEAM

COMPRESSOR

60valve trays

140oC

4 PPM H2S max.

FROM FILTER / COALCR.

In case it is found that the LPG is sphere contains more than 4 PPM of H2S

after sampling (as preparation for dispatch to consumers), the bulk of LPG is re-

routed through Caustic Wash Unit to restrict the H2S level below permissible limit.

29

LPG COLUMN10 kg/cm2

TO FLARE

LPG TO SPHERE

NGL TO KRU / TANK

HP STEAM

FRM STRIPPER BOTTM.

REFLUX DRUMREFLUX

190 oC

60 oC

60 valve trays

KEROSENE RECORY UNITNGL produced from CFU is given value addition in KRU by way of producing aromatic rich naphtha (ARN), superior kerosene oil (SKO), heavy cut (HC) and/or high-speed diesel (HSD). The hot NGL is fed to Naphtha Column for distillation from where Naphtha is recovered as a top product. The bottom stream is fed to the Kerosene column through the gas fired furnace for further fractionation .Kerosene/ ATF is recorded from top of the Kerosene Column and HSD/ Heavy Cut is recovered from the bottom. A suitable chemical additive is

added in ATF to maintain electrical conductivity, and storage stabilizer for HSD before these products are sent to storage.

LPG RECOVRY UNIT: A part of sweet gas from outlet of GSU (about 5 MMSCMD) and all the sweet condensate from DPD are taken as feed to LPG Recovery Unit. State-of-the-art cryogenic process using Turbo-Expander has been used for the first time in ONGC. The feed gas is first dried in molecular sieve dryers and then chilled in a Cold Box to (-) 300 C. The chilled vapor is expanded isentropically in Turbo-Expander wherein temperature of the gas falls to (-) 570 C. The heavier hydrocarbons (C 3+) get liquefied in the chilling process, which are separated for fractionation in LEF and LPG columns. The lean gas liberated from top of LEF column is further compressed as per requirement of downstream consumers. The products coming out from LPG column are LPG as a top product and Naphtha as a bottom product. A part of LPG is further distilled to obtained propane, which is used as a refrigerant in LPG and DPD unit.

LPG Spheres:-

The output from LPG stripper columns are generally LPG and other gases.This LPG is stored in large LPG spheres.This LPG is forced to the hight of the LPG spheres by pumps.

The design of the spheres are of spherical shape.There are 2 main reasons for it.

1. The inlet fire water from the top can be easily expanded as it enters the spheres. And is given for insulation process.

2. The stresses devloped on the sharp edges of other shapes like cubic shape, cylindrical shape etc, are hiher according to LAME’S Theorm . Whereas in

spherical shape there are no sharp edges which reduces the stress development.

The spheres are situated at several hights from ground because it causes sufficient presure different due to difference in height.

UTILITY SYSTEMUnder Utility and Mechanical Maintenance Unit, there comes the following

1) IG plant

2) Cooling towers

3) Heat Exchangers

4) Fire water

5) Steam

IG PLANT

Utility department meets the basic requirements of the plants which are necessary

For plant to run such utilities are1.air2.water3.steam1.Air -there are 3 types of air a) plant air-plant air is compressed air used in cleaning purpose. b) Instrument air- instrument air is compressed air without moisture content. main use of instrument air is to actuate pneumatic valves.c) inert gas- inert gas in plant is produced by removing oxygen content from instrument air and it is used where there are chances of fire. During purging of the LPG spheres N2 is used.

KSS/HZR-UTLT/2002 14

X 101

C 101

H 101

CW

FG

SEAL POT

V 101

C 102 A

C 102 C

C 102 B

X 102

V 102

E 102V 104

X 103

V 105 AD-A

V 105 AD-B

V 106

X 105E 103E 104

V 107

P 103 A/B

IG PLANT - PFD

AIR BLOWER

COMBUSTION CHAMBER

SUMP

KOD

FILTER

PROTECTOR

COMPRESSORS

AFTER COOLER MOISTURE

SEPARATOR

PRE FILTER

DRYERS

FILTERHEATER

AFTER COOLER

MOISTURE SEPARATOR

IG RECEIVER

FROM TR. B

TO TR. B

KSS/HZR-UTLT/2002 10

PRE FILTER HEATER

FIC

TOWER I TOWER II

x

x

x

4 WAY VALVE

COOLERMOISTURE SEPARATOR

AFTER FILTER

IA TO HEADER

FROM COMP.

190oC

185oC

35oC

BANK I 190oC

BANK II 220oC

BANK III 220oC

AIR DRYERS

KSS/HZR-UTLT/2002 16

COMP RESSORS

AIR RE CEIVE R

PRE FILT ER

ADSORBE RS

O2

BLOW SILEN CE R

F 001

V 104 A V 104 B V 102

N2

VESSEL

PRODUCT GAS FILTERS

V 43 - 1

F 002 / F 003

V 43 - 2

N2

BLOW SILEN CER

FI 101

PRODUCT FLOW ME TE R

V 103

PRODUCT N2

STORAGE

N2 PLANT PFD

K 101A

K 101B

V 101

25K001

HEAT EXCHANGER

A heat exchanger is a device used to transfer heat between one or more fluids. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contactInside ongc hazira only two types of heat exchangers are used1.shell and tube type-Shell and tube heat exchangers consist of series of tubes. One set of these tubes contains the fluid that must be either heated or cooled. The second fluid runs over the tubes that are being heated or cooled so that it can either provide the heat or absorb the heat required. A set of tubes is called the tube bundle and can be made up of several types of tubes: plain, longitudinally finned, etc. Shell and tube heat exchangers are typically used for high-pressure applications (with

pressures greater than 30 bar and temperatures greater than 260 °C).This is because the shell and tube heat exchangers are robust due to their shape.Several thermal design features must be considered when designing the tubes in the shell and tube heat exchangers: There can be many variations on the shell and tube design. Typically, the ends of each tube are connected to plenums (sometimes called water boxes) through holes in tubesheets. The tubes may be straight or bent in the shape of a U, called U-tubes.

2.plate heat exchanger

A plate heat exchanger is a type of heat exchanger that uses metal plates to transfer heat between two fluids. This has a major advantage over a conventional heat exchanger in that the fluids are exposed to a much larger surface area because the fluids spread out over the plates. This facilitates the transfer of heat, and greatly increases the speed of the temperature change. Plate heat exchangers are now common and very small brazed versions are used in the hot-water sections of millions of combination boilers . The high heat transfer efficiency for such a small physical size has increased the domestic hot water (DHW) flowrate of combination boilers. The small plate heat exchanger has made a great impact in domestic heating and hot-water. Larger commercial versions use gaskets between the plates, whereas smaller versions tend to be brazed.

The concept behind a heat exchanger is the use of pipes or other containment vessels to heat or cool one fluid by transferring heat between it and another fluid. In most cases, the exchanger consists of a coiled pipe containing one fluid that passes through a chamber containing another fluid. The walls of the pipe are usually made of metal, or another substance with a high thermal conductivity , to facilitate the interchange, whereas the outer casing of the larger chamber is made of a plastic or coated with thermal insulation , to discourage heat from escaping from the exchanger.

COOLING TOWER

Cooling Tower is the utility which is used to cool the hot water received from various parts of plant with heat transfer from atmosphere.There are 2 types of cooling tower1.cross flow cooling tower

Crossflow is a design in which the air flow is directed perpendicular to the water flow (see diagram at left). Air flow enters one or more vertical faces of the cooling tower to meet the fill material. Water flows (perpendicular to the air) through the fill by gravity. The air continues through the fill and thus past the water flow into an open plenum volume. Lastly, a fan forces the air out into the atmosphere.

A distribution or hot water basin consisting of a deep pan with holes or nozzles in its bottom is located near the top of a crossflow tower. Gravity distributes the water through the nozzles uniformly across the fill material.

Advantages of the crossflow design:

Gravity water distribution allows smaller pumps and maintenance while in use.

Non-pressurized spray simplifies variable flow.

Typically lower initial and long-term cost, mostly due to pump requirements.

Disadvantages of the crossflow design:

More prone to freezing than counter flow designs. Variable flow is useless in some conditions.

More prone to dirt buildup in the fill than counter flow designs, especially in dusty or sandy areas.

2.counter flow cooling tower

In a counter flow design, the air flow is directly opposite to the water flow (see diagram at left). Air flow first enters an open area beneath the fill media, and is then drawn up vertically. The water is sprayed through pressurized nozzles near the top of the tower, and then flows downward through the fill, opposite to the air flow.

Advantages of the counter flow design:

Spray water distribution makes the tower more freeze-resistant. Breakup of water in spray makes heat transfer more efficient.

Disadvantages of the counter flow design:

Typically higher initial and long-term cost, primarily due to pump requirements.

Difficult to use variable water flow, as spray characteristics may be negatively affected.

Typically noisier, due to the greater water fall height from the bottom of the fill into the cold water basin

Parameters of cooling tower-Range-The range is the temperature difference between the warm water inlet and cooled water exit.Approach — The approach is the difference in temperature between the cooled-water temperature and the entering-air wet bulb temperature (twb). Since the cooling towers are based on the principles of evaporative cooling, the maximum cooling tower efficiency depends on the wet bulb temperature of the air. The wet-bulb temperature is a type of temperature measurement that reflects the physical properties of a system with a mixture of a gas and a vapor, usually air and water vapor Approach=temp. of cooling water- temp. of saturated air Approach is generally between 2-3 `CCooling Efficiency –

he cooling tower efficiency can be expressed as

μ = (ti - to) 100 / (ti - twb) (1)

where

μ = cooling tower efficiency (%) - common range between 70 - 75%

ti = inlet temperature of water to the tower (oC, oF)

to = outlet temperature of water from the tower (oC, oF)

twb = wet bulb temperature of air (oC, oF)

The temperature difference between inlet and outlet water (ti - to) is normally in the range 10 - 15 oF.

KSS/HZR-UTLT/2002 29

SYSTEM

BASIN

PUMP

FAN

AIR

SYSTEM

PUMP

FAN

BASIN

AIR

CROSS FLOW INDUCED DRAFT

COUNTER FLOW INDUCED DRAFT

TYPES OF COOLING TOWERS

KSS/HZR-UTLT/2002 43

ACID STORAGE TANK ACID TRANSFER PUMP

P 206

V 210

T 203 A T 203 B T 203 C

X 204

FAN X203

BASINCHANNEL

SUMP

PUMP P 204

MAKE UP WATER

FIRE WATER

SUMP LEVEL CONTROLLER

SAND FILTER X 207

SHMP HEDP ZnSO4

Cl2

FROM SYSTEM

MAIL CELL O/L VALVE

T 202

COOLING TOWER PFD

KSS/HZR-UTLT/2002 52

20 T 213

20 P 207 A/B

RAW WATER STORAGE TANK

STRONG ACID CATION EXCHANGER

22X202A/B/C22X201A/B/CWEAK BASE ANION EXCHANGER

22V201A/B DEGASSED WATER TANK

22C201A/B DEGASSING TOWER

22B201A/B/C/D AIR BLOWERS

22X203A/B/CSTRONG BASE ANION EXCHANGER

22X204A/B/CMIXED BED EXCHANGER

22T201DM WATER TANK

20T201DM WATER TANK

22P205A/B/C

20P205A/B

TO HP BOILERS

TO MP BOILERSNEUTRALISATION PIT

22P203A/B

TO OWS

22P201A/B/C/DHCL NaOH

AIR HCL NaOH

DM WATER PLANT

DM water stands for demineralized water. The minerals such as calcium, magnesium, that has tendency to form scales of carbonates inside the tubing, has to be remov-ed before it is taken into use as a water feed to the boiler. So there is a dedicated plant set up to remove the minerals.

As explained in the above diagram, the cations and anions of the water are removed separately.

COGENERATION PLANT(CO-GEN)Cogeneration plant is the responsible for all the power and steam requirement of the plant. Cogen Plant has a total capacity of producing 50MW power out of which approx. 30 MW is used by the plant and rest is either delivered to DGVCL and consumed by the offices at the site, meets the power requirement of the ONGC Nagar.

INTRODUCTION:Cogeneration means simultaneous generation both electrical and thermal energy by raising a single primary heat source, thereby increasing the overall efficiency of the plant. Cogeneration is one of the most powerful and effective energy conservation techniques. In industries like refineries, petrochemical, fertilizer, sugar etc, there is a requirement of both power and steam. LPG/CSU plant at Uran needs power and steam. To meet this requirement a cogeneration plant was setup. Hence this plant fulfills the requirement of both electrical power and steam at a very low cost and high efficiency and reliability.

Cogeneration is of two types namely

Copping up cycle Bottom up cycle

Copping cycle is one of in which heat requirement is attained by externally firing the fuel. Whereas in bottom up cycle the heat requirement is fulfilled by internal chemical reactions this cycle is used in medicine production. Cogeneration plant at ONGC Uran is based on copping up cycle. The principle of this plant is mentioned below:

PRINCIPLE:Air from atmosphere is taken through an air filter and compressed in axial flow compressor driven by the turbine. The compressor air enters into combustion chamber where it is mixed with fuel (lean gas). During combustion its temperature increases at constant pressure (process B to C) then it expands mechanical energy by rotating the turbine. A major part of this energy is available for the generator. Hence the thermal efficiency of the generator is very low Diesel engine is used for initial cranking of the system. Once the turbine attains the speed the contact is broken. However only 30% of the compressed air is used for combustion and

Energy conversion and the rest of the air are used for cooling and sealing of the net bas path (Turbine blades nozzles etc). The efficiency of the turbine can be increased if the metallurgical part of the nozzle and blades are improved so that the size of the compressor can be reduced for the same turbine

What is Cogeneration?

Cogeneration is the process whereby a single fuel source, such as natural gas, is used to produce both electrical and thermal energy. By definition, an onsite cogeneration system is more efficient than a utility operated central power plant since thermal energy that would otherwise be wasted is captured for use at the facility. The result is a much more efficient use of fuel which can generate substantial savings for the end user. Conventional electrical generation by a utility central plant is only about 35% efficient compared to the 90% efficiency of an Intelligent Cogeneration Unit by IPS.

Because Intelligent Power Systems cogeneration equipment is so efficient, most installations deliver significant energy cost savings.

If your facility has a need for thermal energy, in the form of heating and/or cooling, you are a good candidate for a cogeneration system. Intelligent cogeneration systems can provide Electricity, Cooling, Heating, Hot water or Steam.

An Intelligent cogeneration system uses less fuel to produce the same amount of energy -saving money and helping to protect the environment

Some Facts about Efficiency: A typical facility will purchase electricity from the utility and fuel (gas or oil) to power a boiler for hot water and heating. This process is inefficient and expensive when compared to producing electrical and thermal energies onsite through cogeneration with Intelligent Power Systems.

Transmitting power from a central power plant across long distances carries the unfortunate price of a significant waste of power. By the time electricity reaches your facility, much of the energy used to produce the electricity is wasted. Electricity sent over the utility grid is generally between 25% and 35% efficient - which means that as much as 75% of the energy used by the utility to generate and transmit electricity is lost before it even gets to you. By definition, this inefficiency flows through to you as a customer in the form of higher electric rates.

An existing hot water heater (boiler) is typically anywhere from 50% to 80% efficient, which wastes as much as one-half of the input fuel.

The poor overall efficiency of separate electric and thermal energy production is bad news for the environment and for your profitability.

The good news is that Intelligent Power Systems equipment provides electricity and hot water at a combined efficiency that approaches 90%.

Electricity created right where it is used, at your facility, has no detrimental power line loss. More importantly, exhaust heat is recovered and provided to your facility as useable energy. Overall, the process is more efficient, which leads to savings for you, and the environment.

Depending on your circumstances, your savings can be substantial compared to the conventional methods of meeting your energy needs.

Layout Diagram of the Co-Generation Plant

Power capacity of the gas turbine (GT):

Power- 3*19.6 MWGE frame- 5 gas turbines

Steam capacity of the waste heat recovery boilers (HRSG):

Steam- 2*75+1*90 TON/HRWaste heat recovery boilers

Plant demand for power and steam:

Power average - 41.0 MW/HRPower (peak) - 50.0 MW/HRSteam - 150 TON/HRExport (with 3 GTS) - 5.0 MW/HRImport (with 3 GTS) – NIL

This power and steam demand is easily met by the Co-generation plant as the power turbines produce 3*19.6 MW= 58.8 MWThe steam produced by the HRSG is 2*75+1*90 TON/HR = 240 TON/HR But sometimes one of the gas turbine may not be operational as mechanical failure may occur, fuel gas line may leak, seizure of the compressor of the turbine etc. The Co-generation plant is always connected to the power grid MSEB in the case of failure of one of the turbines. Thus undisturbed power supply continues

Electric power to all the facilities and township at Hahira is supplied by cogeneration power plant through three gas turbine generators. These turbines are based on total energy conservation concept. The heat energy of gas turbine exhausts is used for generation of high, medium and low pressure steam for use in various process units. Excess power from the plant is wheeled to GEB grid for revenue generation.

How Cogen Works:

1. Two natural gas-fired combustion turbines drive generators to produce electricity.

2. The hot combustion gases from each turbine pass through a corresponding heat-recovery steam generator (HRSG) to produce steam. The HRSGs contain duct burners to produce additional steam as needed.

3. The high- and low-pressure steam from the HRSGs passes through a single extracting/condensing steam turbine that sends heating steam to the UW and produces electricity for the Madison area.

4. The exhaust steam is sent to a condenser and then cooled by cooling towers. This process forms water that is reused.

5. Centrifugal chillers provide 20,000 tons of chilled-water capacity. Electric-driven chillers use roof-mounted cooling towers for heat rejection.

6. The steam heat and chilled water is used on the UW-Madison campus.

7. The electricity is sent to an adjacent substation and then to the Madison area.

Cogeneration & CHPCogeneration (cogent) through combined heat and power (CHP) is the simultaneous production of electricity with the recovery and utilization heat. Cogeneration is a highly efficient form of energy conversion and it can achieve primary energy savings of approximately 40% by compared to the separate purchase of electricity from the national electricity grid and a gas boiler for onsite heating. Combined heat and power plants are typically embedded close to the end user and therefore help reduce transportation and distribution losses, improving the overall performance of the electricity transmission and distribution network (see district energy for more details). For power users where security of supply is an important factor for their selection of power production equipment and gas is abundant, gas-based cogeneration systems are ideally suited as captive power plants (i.e. power plants located at site of use).

Benefits of Gas Engine CHP

The high efficiency of a CHP plant compared with conventional bought in electricity and site-produced heat provides a number of benefits including

On site production of power Reduced energy costs Reduction in emissions compared to conventional electrical generators and

onsite boilersHeat Sources from a Gas Engine

The heat from the generator is available in from 5 key areas:

1. Engine jacket cooling water2. Engine lubrication oil cooling3. First stage air intake intercooler4. Engine exhaust gases5. Engine generator radiated heat, second stage intercooler

1, 2 and 3 are recoverable in the form of hot water, typically on a 70/90˚C flow return basis and can be interfaced with the site at a plate heat exchanger.

The engine exhaust gases typically leave the engine at between 400 and 500˚C. This can be used directly for drying, in a waste heat boiler to generate steam, or via an exhaust gas heat exchanger combining with the heat from the cooling circuits. 5. The heat from the second stage intercooler is also available for recovery as a lower grade heat. Alternatively new technologies are available for

the conversion of heat to further electricity, such as the Organic Rankine Cycle Engine.

CHP applications

A variety of different fuels can be used to facilitate cogeneration. In gas engine applications CHP equipment is typically applied to natural gas (commercial, residential and industrial applications), biogas and coal gas applications.

CHP System Efficiency

Gas engine combined heat and power systems are measured based upon the efficiency of conversion of the fuel gas to useful outputs. The diagram below illustrates this concept.

Firstly the energy in the fuel gas input is converted into mechanical energy via the combustion of the gas in the engine’s cylinders and their resulting action in the turning of the engine’s crankshaft. This mechanical energy is in turn used to turn the engine’s alternator in order to produce electricity. There is a small amount of inherent loss in this process and in this example the electrical efficiency of the engine is 40% (in reality GE Jenbacher gas engines are typically between 40-48.7% electrically efficient).

THE MAINTENANCE PHILOSOPHY

The continuous operation of Hazira Gas Processing Complex is very critical for keeping the sheels of downstream industries running. Therefore, the down time costs are enormous as compared to the running costs or maintenance costs. In order to keep the plant equipment and machinery in good shape and to achieve highest level of equipment and system availability, a stringent maintenance regime is adopted.

All the plant equipments are divided into three groups

i) Rotary Equipment - Includes all the rotating and reciprocating Eqpts.Such as compressors, pumps, gear boxes,

engines, Motors, agitators, fans, conveyers etc.

ii) Semi Rotary Eqpts.- Includes eqpts. Such as safety valves, control valves, shutdown valves, MOV’s Manual operated valves, NRV’s.

Iii) Static Eqpts. - Includes all eqpts. Such as pressure vessels, heat Exchangers, columns, furnaces, boilers, flare stacks, Piping networks.

The above three groups of equipments are maintained for its regular & long-time needs through dedicated maintenance teams of;

a) Mechanical Discipline.b) Electrical Disciplinec) Instrumentation/Electronics Discipline

Most of the planned and unplanned jobs are carried out during general shift timings (8.45 a.m. to 6.15 p.m.) by the respective maintenance groups dedicated to different units. However to cater to the emergencies and minor jobs during odd hours, a round the clock shift maintenance teams of different disciplines are also deployed. These teams are under the supervision of resident engineers 9RE’s), stationed at the plant itself for 24 hours. This adds to the increased availability of maintenance people during holidays and other odd hours. Apart from this all the key maintenance engineers have been provided with telephones at their residences and can be called for duty within very short span of time.

MAINTENANCE STRATEGIES

In order to keep the equipments and other facilities in proper condition so that risk of equipment failure are minimized, the following maintenance strategies are adopted.

A. PLANT TURNAROUND STRATEGY :

- The complete plant is subdivided into a number of units based on t their operations and the units are further broken up into Trains (Process Streams).

- With continuous operation of the equipments and various systems, their efficiency slowly reduces over the time. In order to bring these systems back to original efficiency and also to attend to many accumulated maintenance jobs, the units are shutdown, one by one, and repair/maintenance work is carried out. This whole process of planned shutdown and turning around the plant efficiency, is called plant turn around. The plant turn around are also necessary to meet the statutory requirements of OISD standards and Factory Act requirement, to inspect all the Pressure Vessels once in four years and get the safety certificates from these agencies.

- Since the whole plant cannot be put under shut down to take up the turn around jobs, a running plan strategy is adopted so that different units turn around is staggered over a period of time.

- During the turn around, the unit is positively isolated from other process units and all the rotary, semi static and static equipments are taken up for repairs/overhauls/inspection etc. To accomplish this help from expert outside agencies/OEM representatives, etc. is obtained. The planning and execution of turn around work is closely monitored by the management. A typical plan for carrying out the turn around, is placed at Annexure-II.

During turn around safety is ensured for safe working. After depressurising/drawing the medium from vessels/tanks/etc. inert gas/steam/plant air purging is carried out. Before man entry oxygen content is measured (min 20%) in the equipment.

All nozzles to the equipment are blinded. Internal cleaning and inspection carried out. Hydrotesting is normally done at 15 times design pressure for 30 minutes. After hydrotesting water is depressurized, drained and equipment is dried up. IG purging is again carried out after deblinding of nozzles to ensure oxygen content below 0.5%.

B. Rotary Equipment Maintenance Strategies :

The equipment critically can be described in the following categories;

i) Category -A+ Main process equipments of continuous operation not having standby and whose outage results in immediate production loss.

ii) Category –A Main process equipments of continuous operation but having standby and whose outage results in immediate production loss.

iii) Category- B Process and auxiliary equipment usually spared, whose outage does not normally cause immediate production loss.

iv) Category –C All process equipments required for intermittent operation.

There are over 714 rotary equipments in HGPC. A summary of rotary equipments is placed at annexure-I. Now depending upon the criticality of the equipment the spares availability and maintenance needs are given due priority.

All the rotary equipments are subjected to the following maintenance regime.

i) Pro-Active Maintenance

a) Predictive Maintenanceb) Preventive maintenancec) Overhauling

ii) Reactive/Breakdown Maintenance.

A brief about these maintenance techniques.

I) Pro-Active Maintenance I) Predictive maintenance :

While the equipment is in operation any growing internal problem is detected by trouble shooting techniques called CONDITION MONITORING TECHNIQUES.

The recommendations made based on these observations are immediately implemented by the concerned maintenance group. This helps in preventing the unplanned shutdown/breakdowns of the equipments and excessive damage to the parts. This is achieved by system of regular monitoring of vibrations, noise level and lube oil condition, of all the equipments. The frequency of these checks depends on the criticality of the equipments.

iii) Time Bound Preventive Maintenance :

This is the oldest way of preventive maintenance. All the equipments are subjected to monthly, quarterly, half yearly, annual preventive maintenance checks as per the Preventive Maintenance Schedules prepared in advance.

III) Overhauling :

For all the major critical equipments, the overhauls are planned depending on the running hours and the recommendations of Original Equipment Manufacturer (OEM). For category A+ equipment’s these overhauls are clubbed with the plant turn around. Sometimes the experts from OEM are called to carry out the overhauling of the critical equipment’s.

II) Break down Maintenance :

In spite of regular preventive, predictive, and overhaul maintenance, there are a few cases of break down maintenance. These break downs of equipment are attended immediately, sometimes working overnight depending upon the criticality of the equipment.

Each break down case is thoroughly analysed using defect analyses technique, so that such occurrences can be avoided in future. In case of major break down the help from OEM experts is also sought.

The above maintenance regime has been helpful in achieving nearly 100% system availability and above 98% equipment availability.

MECHANICAL COMPONENTS USED INSIDE HAZIRA PLANTPUMPS- Pumps are mainly used to transport liquid for various requirements of the plants . there are 3 types of pumps used in hazira plant in order to pump fluid

1.Centrifugal pump-

The centrifugal pump creates an increase in pressure by transferring mechanicalenergy from the motor to the fluid through the rotating impeller.The fluid flows from the inlet to the impeller centre and out along its blades.The centrifugal force hereby increases the fluid velocity and consequentlyalso the kinetic energy is transformed to pressure

Centrifugal pumps are used in cooling tower in order to pump to cooling water for various cooling applications such as heat exchangers and centrifugal pumps are also used in kerosene recovery unit

2.Reciprocating pump-

Reciprocating are widely used in hazira plant in GDU ,GSU in order to pump MEDA and GLYCOL

3.Screw pump – screw pump is special type of pump used to handle slurry. Screw plant is used in SRU

Gland Packing- gland packing is used to prevent of leakage of fluid being pumped by the pump. That packing is generally used in centrifugal pumps

Mechanical seal- function of mechanical is seal is same as gland packing i.e to prevent leakage of fluid to be pumped and that type of seal is generally used in all types of pumps

Expansion Bellow- Expansion bellow is used to restrict thermal expansion in pipes. Bellow is made of rubber material so that can easily contracted in case of thermal expansion

Compressor- Hazira plant is a gas processing plant so it deals with gas and gas can not be pumped by pumps so compressors are used . There are mainly 3 types of compressors .compressors are used in inert gas plant,GDU,GSU

1.Reciprocating compressor -

SINGLE ACTING RECIPROCATING COMPRESSORS

Single acting compressor is used in GDU and GSU

reciprocating compressor is constructed of metal and has the following main parts :-

1. THE CYLINDERThis is a metal tube-shaped casing (or body), which is generally fitted with a metal lining called a 'cylinder liner'. The liner is replaceable when it becomes worn and inefficient. The cylinder is also fitted with suction and discharge ports which contain special spring loaded valves to allow liquid to flow in one direction only - similar to check valves.

2. THE PISTONThe piston consists of a metal drive rod connected to the piston head which is located inside the cylinder. The piston head is fitted with piston rings to give a seal against the cylinder lining and minimise internal leakage. The other end of the drive rod extends to the outside of the cylinder and is connected to the driver. Modern industry generally used high power electric motors and gearing to convert the rotating motion into a reciprocating action.In a single acting compressor, the backward stroke of the piston causes a suction which pulls in gas (or air) through the inlet valve. (The same suction action keeps the discharge valve closed). On the forward stroke, the positive pressure generated by the piston, closes the inlet valve and opens the discharge valve. The liquid is displaced into the discharge system. Because the action is positive displacement, a piston compressor can generate very high pressure and therefore MUST NEVER be operated against a closed discharge system valve unless it is fitted with a safety relief system in order to prevent damage to the compressor and/or the driver and/or other downstream equipment.

Figure : Single Acting, Reciprocating Compressor (Simplified)

In the old days of piston pumps, the driver used to be (and still is in some cases), high pressure steam which was fed to drive double acting cylinders by a system of valves in a steam chest – like the driver of an old steam engine. The reciprocating action is converted to rotation to drive the engine wheels. (See photograph below).

Figure : – Conversion of Rotation to Reciprocation

DOUBLE ACTING-This type of compressor operates in exactly the same way as the single acting with respect to its action. The difference is, that the cylinder has inlet and outlet ports at EACH END OF THE CYLINDER. As the piston moves forward, liquid is being drawn into the cylinder at the back end while, at the front end, liquid is being discharged. When the piston direction is reversed, the sequence is reversed. With a double acting compressor, the output pulsation is much less than in the single acting.

Screw compressors- A rotary screw compressor is a type of gas compressor which uses a rotary type positive displacement mechanism. They are commonly used to replace piston compressors where large volumes of high pressure air are needed, either for large industrial applications or to operate high-power air tools such as jackhammers.

The gas compression process of a rotary screw is a continuous sweeping motion, so there is very little pulsation or surging of flow, as occurs with piston compressors.

CENTRIFUGAL COMPRESSOR- This type of compressor is used in inert gas plant

Centrifugal compressors, sometimes termed radial compressors, are a sub-class of dynamic axisymmetric work-absorbing turbomachinery. The idealized compressive dynamic turbo-machine achieves a pressure rise by adding kinetic energy/velocity to a continuous flow of fluid through the rotor or impeller. This kinetic energy is then converted to an increase in potential energy /static pressure

by slowing the flow through a diffuser. The pressure rise in impeller is in most cases almost equal to the rise in the diffuser section.