meeting new moef norms: presentation title ( arial,...

International Seminar

On

Environmental compliances in TPPs– Issues and challenges30th January 2017

�Message Box ( Arial, Font size 18 Bold)

Presentation Title ( Arial, Font size 28 )

Date, Venue, etc..( Arial, Font size 18 )

Meeting New MOEF Norms:

Technological & Implementation Challenges for Utilities

Ramkrishna Gadre

CP Tiwari

Content

� About Tata Power Company

� Leader in Technology adoption

� MoEF Norms: Present and Revised

� Challenges in Compliance to Specific water consumption Norm and Conversion of OTC to RTC

System

� Challenges in Implementation of ZLD

� SPM abatement technologies and Implementation challenges


� SPM abatement technologies and Implementation challenges

� FGD Technologies and Implementation challenges

� De- NOx Technologies and Implementation challenges

� Estimated Capital Expenditure and Time Required

� Impact on O&M Cost

� Summary – Technological & Implementation Challenges

India’s largest integrated Power Company 2

About Tata Power Company

� India’s largest integrated power company with presence across the entire value chain - fuel, fuel

logistics, generation, transmission, distribution and power trading

� Founded in 1906 to supply power to Mumbai

» First hydro plant commissioned in 1915

» Set up thermal power plants in Mumbai in 1960s

� Current installed generation capacity is in excess of 10,500 MW including Thermal (Coal, Gas,

WHRSG) , hydro, wind, solar etc.


� Out of the above coal based thermal generation capacity is about 6300 MW (Using Imported and

domestic coal)

India’s largest integrated Power Company 3

First Flue Gas

First 800 MW

supercitical thermal unit

Largest Wind Turbine

Generator 2 MW (Visapur)

Largest single location

photovoltaic installation

3 MW (Mulshi)

First 25 MW

solar power

plant in India

5 y

ea

rs

Leader in technology adoption

First UMPP (4000MW) using super

critical technology


First

150 MW

thermal

unit

First

500 MW

thermal

unit

First

gas

insulated

switch

gear

Computerized

grid control &

energy

management

system

220 kV transmission

lines in four circuit

towers

220 kV

Cable

Transmission

Network

First Flue Gas

De-sulphurization

plant in India using

Seawater

First to Introduce SCADA

and Fibre Optic ground wire

communication

First pump storage unit

in the country of 150 MW

Capacity

45

ye

ars

4

MoEF Norms: Present and Revised

Plant / Unit Year of

Commissioning

Parameters Present Norms

(mg/Nm3)

Revised Norms

(mg/Nm3)

CGPL (Coastal Gujarat

Power Limited) – 5x 800

MW

2012 and 2013 SPM 50 50

NOX Not Specified 300

SOX Not Specified 200

Trombay Unit 5 – 500 MW 1984 SPM 150 100


SOX * 200


SOX * 200

Trombay Unit 8 – 250 MW 2009 SPM 100 50


SOX * 600

Maithon Power Limited –

2 x 525 MW

U1-2011

U2-2012

SPM 100 50



* Trombay station has a limit of 24 TPD of SO2.

5

Plant / Unit Year of

Commissioning

Parameters Present Norms

(mg/Nm3)

Revised Norms

(mg/Nm3)

Jojobera Unit 1 to 3 –

1x 67.5 and 2x 120 MW

U1-1996

U2-2000

U3- 2001

SPM 75 100



Jojobera Unit 4 and 5-

2 x 120 MW

U4-2005

U5- 2011

SPM 50 50


MoEF Norms: Present and Revised for TPTCL units (Contd.)


2 x 120 MW U5- 2011NOX Not Specified 300


All Operating Units All units

commissioned

before Dec 2016

Sp. Water

(m3/MWh)

Not Specified 3.5

Cooling Tower Not Specified Mandatory

6

Impacts of new MoEF Norms

Compliance to Specific water consumption

Implementation of Cooling tower

(Conversion from Once through cooling (OTC) to Recirculation Type Cooling (RTC))

Zero Liquid Discharge (ZLD) compliance


SPM abatement technology

Implementation of Flue Gas De-sulphurisation unit

(De- SOx technology)

De- NOx technology

(Implementation of SCR/ SNCR)

7

Challenges in Compliance to

Specific water consumption Norm and


Specific water consumption Norm and

Conversion of OTC to RTC System

8

� New MoEF norm doesn’t differentiate between raw and seawater while indicating norm restricting

the specific water consumption of the TPP

� Compliance to water consumption norm would be possible only for raw water based inland power

plants

� In coastal power plant based on seawater once through cooling (OTC) system and SWFGD, the

water requirement would be very high compared to latest norm of 3.5 and 2.5 cum / MWh

� In a typical 500 MW unit employing seawater based OTCS and SWFGD, estimated specific water

consumption will be as below:

Challenges - Compliance to Sp. Water Consumption Norm


Sr.

No

Consumers (m3/h)

1 Circulating water system 66000

2 Service water 200

3 Potable water 10

4 De-mineralized water 60

5 Total 66270

6 Intake quantity per MW (m3/ MWh) Approx. 132

9

� The typical water consumption for coastal thermal power plant using seawater for once through

cooling and SW FGD would range between 130 cum/MWh and 145 cum/MWh as against the norms

of 3.5 cum/MWh

� The probable options for these plants to reduce the water consumption up to normative levels can

be as follows:

� Option-1: Conversion of existing OTC system to sea water based RTC system for condenser

cooling + sea water FGD [OTC to Sea Water RTC + Sea Water FGD]


Challenges - Compliance to Sp. Water Consumption Norm (Contd.)



cooling + lime / limestone based fresh water FGD [OTC to Sea Water RTC + Lime / Lime Stone

FGD]

� Option-3: Conversion of existing OTC system to fresh water based RTC system for condenser

cooling + lime/limestone based fresh water FGD [OTC to Fresh Water RTC + Lime / Lime Stone

FGD]

10

� Post conversion to cooling tower based RCT system, seawater will be required CT Make-Up

� Seawater will be required for FGD System for scrubber and dilution requirement

� Cycle of Concentration (COC) of Seawater based RCT System will be 1.3 to 1.5 due to seawater

quality limitations (High TDS and TSS/Turbidity).

� As a result, specific water consumption remains above 50 cum/MWh (including Seawater

requirement for CT Make up and SW FGD)

� Due to make up water requirement of seawater based RCT System & FGD system, specific water

Option-1: OTC to Sea Water RTC + Sea Water FGD


� Due to make up water requirement of seawater based RCT System & FGD system, specific water

consumption is much above the stipulated figure of 3.5 m3/MWh

11

In option-1, it is not possible to restrict the specific Water consumption up to

3.5 m3/ MWh

Option-2: OTC to Sea Water RTC + Lime / Lime Stone FGD

� In case OTC system is converted to RTC system, seawater for FGD will have to be sourced separately

(almost 60% to 65% of current cooling water requirement)

� Due to large seawater requirement for seawater based FGD, it may be explored to replace existing

SWFGD with limestone based FGD system that requires comparatively less water

� Conversion of SW FGD into the lime based FGD would need additional space which would be difficult

in brownfield project

� Lime based FGD would need higher O&M costs towards sourcing of feedstock (limestone) and

operational costs for Limestone/gypsum handling system, limestone sizing, slurry preparation,


operational costs for Limestone/gypsum handling system, limestone sizing, slurry preparation,

gypsum dewatering/disposal, waste water treatment etc.

� Due to seawater based cooling tower (RTC system), the specific water consumption shall still be

much higher than specific water norms.

12

In option-2 also, it is not possible to restrict the specific Water consumption

up to 3.5 m3/ MWh

Option-3: OTC to Fresh Water RTC + Lime / Lime Stone FGD

� Fresh water requirement for typical 500 MW unit for Option-3 will be as under:

Sr No Consumers Consumption for 500 MW unit (m3/h)

1 Cooling tower make up 1395

2 Limestone FGD Cooling tower blow-down

3 Service water 200

4 Potable water 10


� As hypothetical scenario, With fresh water based cooling towers and limestone based FGD,

the specific water consumption for typical 500 MW unit may be restricted to 3.5 m3/MWh.

� However there are several technical challenges /constraints which needs consideration for

this option

5 De-mineralized water 60

6 Total 1665

7 Intake specific water quantity 3.33(m3/MWh)

13

� Conversion of Seawater based CW system into fresh water based RTC system would require

additional fresh water to be sourced

� In case of coastal plants with water scarcity, fresh water for CW requirement would have to be

generated through seawater desalination plant

� Desalination plant and lime/limestone based FGD shall also require additional land, infrastructure,

increased aux. power consumption and additional CAPEX+OPEX.

� Layout constraints: Layout study in existing plants has revealed that installation of desalination plant

+ Cooling tower + Limestone FGD installation in brownfield projects would be highly unfeasible.

Option-3: OTC to Fresh Water RTC + Lime / Lime Stone FGD (Contd.)


+ Cooling tower + Limestone FGD installation in brownfield projects would be highly unfeasible.

14

In view of all the above limitations, option-3 seems to be challenging

implementation especially in brownfield plants

� Conversion of existing OCT to RCT shall need major

modifications like:

• CW piping modifications/ replacement

• Condenser modifications/ replacement

• CW pumps modification/ replacement

• Augmentation of electrical power supply due to

increased Aux. power consumption

Difficulties in Conversion of OTC to RCT system


� Layout and Space constraints in installing Cooling tower &

associated system

� Cooling tower implementation feasibility study at one of

our coastal plant revealed that the current space is

insufficient for locating cooling tower. Cooling tower

installation shall need reclamation of marshy land covered

with mangroves which would not be environment friendly

15

Conversion of OTC to RCT System in existing Coastal Plant is not viable due to above

reasons

Challenges in Implementation of ZLD

(Zero Liquid Discharge)


(Zero Liquid Discharge)

16

� Plant uses raw water for various purpose such as cooling water, service water, potable water etc

� Plant generates different types of effluent water having different types / concentration of

contaminants, variations in flow rates, different frequency of generation of effluents etc.

� The zero liquid discharge condition (ZLD) for thermal power plant would need to recycle and

reutilize these different effluents on continuous basis.

� It is necessary to consider the different scenarios of operating conditions such as:

• Monsoon/ non-monsoon condition,

• Wet/ dry mode of ash disposal,

Challenges in implementing ZLD in TPP


• Wet/ dry mode of ash disposal,

• Variations in water requirement for coal handling,

• Water requirement for horticulture

• Effluent utilization opportunities

� Depending on the effluent water balance, the treatment scheme will have to be designed for

treating of high TDS complex waste priority wise

� The high recovery treatment plant is one such good option (>95% recovery plant)

17

SPM abatement technologies and Implementation Challenges

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Suspended Particulate Matter and its Challenges

� Options available for retrofitting of ESP to meet new norms

� Installing additional fields in the upstream/ downstream of ESP

� Increasing the height of ESP.

� Addition of pass parallel to existing ESP

� Challenges includes

� Layout constrain in addition of new field in the upstream/downstream of existing ESP.

� Replacement of ID fan may be required to suit the higher pressure drop across New ESP.


� Increase in height of ESP may require re-design of existing structure and foundation. The

existing foundation details may not be available.

� Space constraint for addition of New Pass.

19

FGD Technologies and implementation Challenges


FGD Technologies and implementation Challenges

20

Overview of all different FGD technologies

� Wet FGD

Uses Aqeous Limestone (Ca(OH)2) in slurry form

Dominantly used in Non- coastal power plants

� Dry FGD

Uses Quick Lime (CaO) in dry powdered form

Due to dry waste handling issues not much in use nowadays

� Sea water based FGD

Makes use of Sea water, Best suited for coastal power plants


Makes use of Sea water, Best suited for coastal power plants

� FBC Boiler

Lime is mixed with bed material and helps to absorb sulphur in furnace

21

Wet Limestone based Flue gas Desulphurization


Difficulties in Installation of Wet Limestone FGD:

� Area within existing & Layout Constraints: Substantial footprint required for facilities like

limestone handling/storage, gypsum handling/storage, slurry preparation system, gypsum

dewatering system, waste water treatment plant etc. Absorber tower and GGH need space close

to chimney which becomes difficult if no sufficient space is provided in original layout.

� Sourcing and Logistics of Limestone: The plant would need access to the limestone on continuous

basis for the operation of FGD. The same may be constrained in many areas due to logistical issues

/ availability issues (For 1000 MW limestone requirement would be approx. 300 TPD)

� Disposal of gypsum: Huge quantity of Gypsum will be generated on a daily basis that would need

large storage pond and evacuation facility (For 1000 MW Gypsum generated daily would be


large storage pond and evacuation facility (For 1000 MW Gypsum generated daily would be

approx. 550-600 TPD)

� Waste water treatment: The waste water from limestone FGD would require the treatment

system to effectively treat the effluent and maintain ZLD for plant.

� Increase in Aux. power requirement (approx. 1.5%) and may need major augmentation in

electrical power supply system to meet this Aux power requirement

� Increased OPEX: The plant OPEX will increase substantially due to increased costs towards

limestone sourcing etc. (Approx. 40 crs. per annum. for 1000 MW plant).

23

Dry Lime based Flue gas Desulphurization


Difficulties in installation of Dry Lime based FGD

� Area within existing layout: Dry Lime FGD faces similar issue of space availability in existing plant

layout especially older plants where sufficient space not provided in original layout.

� Based on the recent reports, Generation capacity of around 90 GW (430 units) is facing problem

due to non-availability of space for FGD.

� Sourcing and logistics of lime: The sourcing of lime will be issue in many areas.

� Byproduct utilization will be challenge


� High cost of reagent: Lime is costlier than Limestone, hence usage may be limited to smaller plant

capacities only.

� Increase in Aux. power requirement (approx. 0.5 to 1%) and may need major augmentation in

electrical power supply system to meet this Aux power requirement

25

Seawater based Flue gas Desulphurization (SWFGD)


� Sea water by nature is alkaline with pH around 8.0 to 8.3. It contains an excess of calcium & sodium carbonates in solution. Theses components gives seawater a substantial capacity to absorb and neutralize SO2from flue gases.

� Only Seawater and air is used in the process, no chemicals/ special materials required

� No secondary waste products generation and hence no disposal issues

� The FGD outlet seawater is treated (dilution/ aeration) before discharge so as to meet the general effluent discharge norms.

Sea Water based FGD Technology


� The absorbed SO2 is transferred into sulphate ions, which is natural constituent of sea water for marine environment.

� The acidic nature of the scrubber water is mainly because of absorption of CO2 and SO2. On aeration the dissolved CO2 escapes out. This together with oxidation of S03 and HC03 brings back the pH & O2 of the scrubber water very close to its original value.

27

Challenges in installation of new SWFGD

� Area within existing layout: The installation of seawater FGD needs substantial footprint for

scrubber tower and auxiliary systems, seawater supply and seawater treatment scheme etc.

� Sourcing of seawater: Seawater for FGD requirement is usually about 20-25% of total CW flow

rate of the unit. In case of OTC system based on seawater it would be possible to tap it from CW

outlet by suitable means.

� It will be furthermore difficult to source seawater in case plant switches to seawater based RTC

system. The same may require separate FGD seawater pumping scheme.

� Treatment of FGD outlet seawater: The seawater treatment needs elaborate system for dilution

and aeration. Construction of the dilution and aeration basin alongside the existing outfall


and aeration. Construction of the dilution and aeration basin alongside the existing outfall

channel/ seal well and its connection would be challenging task.

� In case of seawater based RTC system, the seawater for dilution will not be available and the

process may need chemical dosing for pH correction.

� Variations in requirement of scrubbing water, Dilution and Aeration scheme depending on the

technology provider makes it difficult to plan the scheme/layout/costing in advance prior to

order finalisation

28

� Flue gas duct design:

• Difficulty in duct modifications in older plants including GGH inlet / outlet ducting

� Design of dilution basin/aeration basin and it’s interconnection with existing CW channel/ seal

well in SWFGD:

• It may require the temporary diversion of the CW outfall channel

• CFD modelling/ physical modelling study would be required for hydraulic design

� Outage requirement: Implementation of FGD would require approx. 1 to 4 months outage

Other technological challenges in implementing FGD


� Outage requirement: Implementation of FGD would require approx. 1 to 4 months outage

� Chimney lining of stack post FGD-

• To avoid the corrosion at lower flue gas temperature chimney shall require the acid proof

lining

• Lining activity may need longer outage (> 3 to 4 months)

� Vendor specific changes in the seawater requirement for scrubbing and dilution makes it

difficult to plan the scheme/layout/ Overall Project Cost estimate prior to bidding

29

De- NOx Technologies and Implementation Challenges


De- NOx Technologies and Implementation Challenges

30

NOx Generation & Available De-NOx Technologies

NOx Type Fuel NOx Thermax NOx

Source: NOx formed from Nitrogen in

the Fuel.

NOx formed from N2 in the

Combustion Air.

Formation Sensitive to: • Oxygen Availability

• Fuel Nitrogen Content

• Kinetics

• Furnace Temperature

• Oxygen Availability


Proportion 60% - 80 % 20% – 40 %

Technologies available for NOx abatement:

• Combustion Technology

• SNCR (Selective Non Catalytic Reduction)

• SCR (Selective Catalytic Reduction)

Combustion Technology

� Type of Combustion technologies:

� Low-NOx Burners (LNB):

� Better air and fuel mixture

� Improves staged combustion process.

� Optimize air requirement during primary combustion of coal.


Optimize air requirement during primary combustion of coal.

� Over Fire Air (OFA) / Seperated Over Fire Air (SOFA):

� Better air staging.

� Approx. 70% through LNB and 30% through OFA / SOFA.

� Expected reduction in NOx level < 20%.

Combustion Technology (Contd.)


Typical Scheme of Windbox Arrangement for Low NOx

Challenges in Combustion Technology

� Challenges:

� Modification to existing windbox/ burner arrangement.

� Modification to the existing air duct / structure to accomodate SOFA arrangement.

� Shut down of approx. 6 to 14 weeks depending on extent of work involved.

� Impact on boiler efficiency.


Selective Non Catalytic Reduction (SNCR)

� Selective Non Catalytic Reduction:

� Introducing reagent at appropriate section of furnace where flue gas temperature is

the range of 850 to 11000C.

� Injection ports provided either by multiple injectors or by using retractable lances

with multiple nozzles.

� Injection rate is controlled through each nozzle w.r.t boiler load to minimize reagent


� Injection rate is controlled through each nozzle w.r.t boiler load to minimize reagent

slip.

� Mixing of reagent either with water or compressed air.

� Expected reduction in NOx level < 50% max.

Selective Non Catalytic Reduction (Contd.)


Typical Scheme of Selective Non-Catalytic Reduction

Challenges in SNCR Technology

� Challenges:

� Approx. 4 to 8 weeks of shut down.

� Ammonia slip to be kept minimum (less than 10 ppm).

� Ammonia storage and handling and space requirement.

� Provenness of OEMs in Indian context and for bigger units


� Selective Catalytic Reduction (SCR):

� Uses catalyst and hence installed at low temperature zone of furnace

� Temperature required is in the range of 250 to 4000C.

� Located between economizer and air pre heater.

� Injection of Aqueous ammonia / Anhydrous ammonia / Urea into hot flue gas through

injection grid.

Selective Catalytic Reduction (SCR)


� Mixture passes through a catalyst surface where the NOx is converted into nitrogen

and water.

� NOx reduction efficiency shall be from 50% to 95%.

Selective Catalytic Reduction (SCR) (Contd.)


Typical Scheme of Selective Catalytic Reduction System

Challenges in SCR Technology (Contd.)

� Challenges:

� Catalyst:

� Use of metals such as Molybdenum, Vanadium, Tungsten etc. in catalyst. Hence

this is costly alternative.

� Catalyst designs for low ash coal used in countries abroad are well established.

Use of these catalyst for high ash containing Indian coal are to be proven.


� Cyclone technology proposed by OEMs needs validation.

� Expected life of catalyst is max 3 years. Availability and regeneration facility of

catalyst on long term after first instillation is concern.

� Disposal of catalyst is a challenge. Presently there is no guideline for disposal.

� Auxiliary Power:

� Introduction of catalyst increases pressure drop in fuel gas path.

� Increase ID fan loading and auxiliary power consumption of unit. In some cases

replacement of ID fans may be required.

� Increase in auxiliary power shall be 0.5 to 0.7%.

� Layout Requirement:



� Space requirement to accommodate reactor in the existing layout.

� Modification in the existing duct.

� Support and strengthening of existing boiler structures.

� Non availability of data for existing plant for layout, foundation details etc.

� Effect on Performance:

� Ammonia bisulphate formation lead to air preheater fouling which may reduce the

air preheater effectiveness.

� Cost and Schedule:

� Structural design cost due to catalyst weight and reactor span is considerable.

� The cost and schedule of implementation shall be reconfirmed.

� Provenness:

� Provenness of OEMs in Indian context.



� Challenges for use of reagents:

� Anhydrous Ammonia: Harmful for biological life and difficult to handle.

� Ammonia solution (19 to 25% in water): Handling cost due to dilution.

� Urea:

� Available in India is a challenge and needs to be imported.

� Requires elaborate heating arrangements for tank, pipe lines etc. for handling



� Requires elaborate heating arrangements for tank, pipe lines etc. for handling

urea solution.

� Handling of Ammonia, Storage within existing layout needs detailed analysis


Estimated Capital Expenditure and Time Required

Installation of pollution control equipment is expected to have an avg impact

of 20-40 paise per unit of electricity

Additional Fixed

Cost (e) (Rs./kWh)

0.455 yrs

Pollutant Technology Analyst Cost

Estimates (Rs

lakh/MW)

Impact on

Levelised

Tariff

(Rs / unit)

Construc

tion Time

(Months)

Downt

ime

(Days)

Particulate

Matter

ESP

Upgradation

10 – 15 0.02 – 0.03 3 – 6 20 –

30

SOx FGD 50 – 60 0.11 – 0.13 18 – 24 30 –


0.00 0.50

25 yrs

15 yrs

10 yrs

Bala

nce

Life

Source: Ministry of Environment and Forests, CSE (Proceedings of

Stakeholder Workshop, Sep 2016)10

0.28

0.23

0.20

SOx

Emission

FGD 50 – 60 0.11 – 0.13 18 – 24 30 –

90

NOx

Emission

SCR/SNCR 10 – 25 0.02 – 0.05 4 – 5 7 – 30

Water Cooling Tower

(Cap Ex for

Coastal Plants)

25 - 35 0.05 – 0.07

Total Inland Plants 70 – 100 0.15 – 0.22

Coastal Plants 95 – 135 0.20 – 0.30


Impact on the O&M Costs*

Parameter Plant A Plant B

Annual OPEX

(Rs. Crs)

Cost per unit

(Rs./kWh)

Annual OPEX

(Rs. Crs)

Cost per unit

(Rs./kWh)

CT & CW System 200 0.07 0 0.00

ESP 0 0.00 0 0.00

FGD 200 0.07 18.6 0.02

SCR / SNCR 800 0.27 190 0.16


*at 85% PLF

Typical Opex cost is expected between 25-33% (including Aux) to meet

the new environmental norm. (Based on analyst reports)

11

SCR / SNCR 800 0.27 190 0.16

� Total expenditure expected to implement environment norms will be over Rs 150,000 Cr.

� Fund Availability to fund capital expenditure at such a large scale is a issue

� In existing plants, it may not be possible to implement some of these new MoEF requirements like

RCT System for coastal plants, SCR & FGD System in smaller old units

� Implementation of new Norms will have impact of CAPEX & OPEX on consumer tariff

� Ability of vendors to execute projects nationally at such a large scale may be a challenge

� Short timeframe (Only 1 year left) to implement norms is a major challenge

Summary – Technological & Implementation Challenges


� Short timeframe (Only 1 year left) to implement norms is a major challenge

� Cost of equipments where demand could be more than supply and Indian manufacture content

is yet to be ascertained.

� Challenges of outages timings and management of grid.

Policy of incentive & penalty for complying & non complying Generator with

option of phasing out non complying plant after pre-defined time frame need to

be firmed-up


Website: www.tatapower.com

Email ID:[email protected]

Contact No: 022 67173809

47

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