clean coal technologies for sustainability

8/2/2019 Clean Coal Technologies for Sustainability

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Dr. V. K. SETHI

Prof. & Head

RGPV

Bhopal

CLEAN COAL TECHNOLOGIES FOR

SUSTAINABLE POWER DEVELOPMENT


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PRIORITIES ON ENERGY GENERATION SECTOR:

Increased use of Advanced Fossil Fuel Technology.

Promote CCT in countries where coal is main stayfuel for Power Generation.

Reduce Atmospheric Pollution from EnergyGenerating Systems.

Enhance productivity through Advanced Fossil FuelTechnology.

WORLD SUMMIT ON SUSTAINABLE DEVELOPMENT


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POWER SCENARIO IN INDIA

Installed capacity in utilities (March 31, 2002)

Thermal 73,274 mw

Hydro 25,574 mw

Nuclear 2,860 mw

Wind 1,427 mw

Total 1,03,135 mw

Total energy generation - 383 billion kwh Per Capita Energy Consumption -400 kwh


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DEMAND PROJECTION

YEAR 2012 CAPACITY ADDITION BY SECTORS

Central 46,500 MW

State & IPP 41,800 MW

NCES 10,700 MW

Nuclear 6,400 MW

Total 105,400 MW

YEAR 2020 MIX OF GENERATION

Thermal 326,000MW Renewable & Hydro 104,000 MW

Nuclear 20,000 MW

Total 450,000 MW


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CLEAN COAL TECHNOLOGIES

Mining Management & Practices(Reduction of Extraneousmaterial)

Coal Preparation Process after mining to improve

inherent & Extraneous material(washing & beneficiation)

Conversion Technologies Supercritical, PFBC and IGCC

Post combustion cleaning Particulate and gaseouspollutants removal(Environmental requirement)


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VISION 2020

PROGRAM

Post combustion Clean-up-Desulfurization

(FGC systems) Supercritical

In-combustion Clean-upFluidized bed

combustion (CFBC,PFBC, AFBC)

Gasification using +fluidized bed, moving bedor Entrained bed Gasifiers

Pre combustion Clean-up beneficiation/washing

Technologies for utilization of Coal for Power Generation with minimalpollutants discharged to the atmosphere (Reduced CO2, Sox, Nox,

SPM) at high conversion efficiency

.World Coal Institute.

CLEAN COALTECHNOLOGIES


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TECHNOLOGIES

Clean Coal Technologies (CCTs)are defined as technologies designed

to enhance:

Efficiency of conversion

Environmental acceptability of coal

extraction, preparation and use.


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COAL FOR POWER

GENERATIONChina and India are projected to account for30%

of the worlds increase in energy consumption

between 2000-2020 and 92% of increase in coal use.

The key environmental challenges facing the coalindustry are related to :

Coal Mining

Particulate emission

Disturbance land me

Acid rain

Ozone and Waste disposal


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INDIA AMONGST TOP SIX

EMITTERS OF CO2Country Total emission Percentage

of

(Million Tonnes of CO2) world emission

USA 5470 24%

China 3121 14%

Russian Federation 1456 6% Japan 1173

Germany 884 4%

India 881 4%


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Note : Green House inventory

for India for Energy Sector(Million Tonnes of CO2)Energy Sector CO2 CO2 equivalent

(CO2+CH4+NOx)

Total Emission 508 565

(58% of total) (64% of total)

Source : IAE : 1999


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PER CAPITA EMISSIONS OF CO2

Top 6 Polluters

World Developed countries

Parties

(Tonnes of CO2 per

capita)

Developing Countries

(Tonnes of CO2 per

capita)

Qatar 44.08

Bahrain 35.23

UAE 30.11

Kuwait 25.01

Singapore 23.47U.S.A 20.50

USA 20.50

Luxemboury 20.42

Australia 16.52

Canada 15.76

Finland 12.47Estonia 12.47

Qatar 44.08

Bahrain 35.23

U.A.E. 30.11

Kuwait 25.01

Singapore 23.47Saudi Arabia 13.27

Note : Per capita CO2 equivalent emissions for India in 1990 are estimated to be

1.194 tonnes or 325 kg of Carbon per capita. This contribution 58% of National

Emissions and 4% of global emission.

Source : IEA 1999 & UNDP 1998.


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COSTOF VARIOUSCO2 MITIGATIONOPTIONS FOR INDIAN POWER SECTOR

Potential

Technologies

1. Co-generation

2. Combined Cycle

3. PFBC

4. IGCC

5. Supercritical

6. Coal Washing

Green house

gas emission

reduction (kg/kWh)

1.50

0.960.18

0.23

0.18

0.125

COST (Rs/Tonnes CO2).

480

260024000

16000

16000

8500Source: ADP 1998


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Zero Emission Technology

(ZET)This technology combines and forms a part of :

Clean Coal Technologies

Solid to liquid fuel technology

GHG mitigation technology Clean Development Mechanism for power sector

Non-CFC Refrigerant and Non-CFC Aerosol PropellantTechnology

Clean Aviation Fuel or ATF for aircraft Substitute LPG for domestic use.


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Measures to achieve Sustainable

Development

Promoting CCTs, including carbon

sequestration is essential to a balanced cost

effective climate change response

Developing countries where coal combustion

efficiencies are low CCT promotion a need ofthe day.


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EFFICIENCY IMPROVEMENT FORECAST

CONVENTIONAL Vs IGCC( Courtesy BHEL)

60555045

403530

1990 1995 2000 2005 2010Year of commercial use

NetThermalEfficiency(%)

Ceramic gasturbine

566 Co 600 Co623 Co 1300 C

o 1500 Co

540 Co650 Co1184 Co

IGCC (15 C Amb)IGCC (Indian Condition)

Super Critical PC Power Plant (15 C Amb.)oSuper Critical PC Power Plant (Indian Condition)

o

Sub Critical PC Power Plant (Indian Condition)


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570

256

384380

0

100

200

300

400

500

600

CO2

MMT

2.84.3

10

6.6

0

5

10

15

SO2

M

MT

85

128

13.3

20

0

50

100

150

ASH

M

MT No Change Scenario

Specific Coal Consumption

=0.75 KG/KWH

Coal

Ash : 43%

Sulphur : 0.6%

Ideal Scenario

Specific Coal Consumption=0.35 KG/KWH

Coal

Ash : 15%

Sulphur : 3%

POLLUTANT GENERATION FROM PC PLANTS

1997

1997

1997

1997

1997

1997

2002

2002

2002

2002

2002

2002


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SOx NOx Particulates

0

10

20

30

40

50

60

70

80

90

100

110

120

PERCEN

TAGE

OFPC

PLANTS

PC

IGCC

PFBC

PC+FGD

RELATIVE EMMISSION


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SUPER CRITICAL UNITS

Standardized Unit Size 660 MW, 246 ata, 537 oC

Station Size 2x660 MW (Minimum) Common Off site facility

FW Temperature 270 oC 275 oC with 6 Heaters.

Total Capacity Planned 14,560 MW *

Number of Units 22 Units

*Includes 6x720 MW and 2x500 MW Imported sets.


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Main advantages of

Super-Critical Steam Cycle

Reduced fuel cost due to improved thermal efficiency

Reduction of CO2 emissions by 15% per unit of Powergenerated compared to sub-critical

Very good part load efficiencies

Plant costs are comparable with sub-critical units


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Current State-of-Art

Super-critical Steam Power Generation Plants

Pressure - 300 bar

Temperature - 600o

CEfficiency - 45% (LHV Basis)

Nickel based alloys allows up 650oC

By the year 2005 - 620 oCBy the year 2020 - 650-700 oC

Cycle Efficiency - 50-55%

& I PE I I


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& I PE I ITECHNOLOGY

Main Thrust Areas : Materials & Metallurgy for components of boiler &

turbine subjected to high temperature and high

pressure. Supercritical cycle optimization -incremental heat rate

improvement

Retrofit of supercritical boiler to subcritical PC boiler

Fluidized bed supercritical steam cycles

Once through HRSGs with supercritical parameters

Multi-reheat supercritical boilers with double/triple

reheater.


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EXPECTED BENEFITS:

Coal Saving 1,565,200 Tonnes

Co2 Emission Reduction 1,909,544

SO2 Emission Reduction 11,648

Ash Reduction 661,752

SUPER CRITICAL SCENARIO


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COAL BASED COMBINED CYCLE PLANT

Routes

Combustion Gasification

Hot Flue gas under pressure

drives the G.T.

Pressurized gasification

process produces fuel forG.T.

Pressurized

Fluidized BED

Combustor (PFBC)

Options Available

Moving BED

Fluidized BED

Entrained BED

COAL BASED


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COAL BASEDCOMBINED CYCLE POWER GENERATION

Offers Plant efficiency over 44% with advanced GT

Has Lower emission of gaseous and solid pollutants

Accept Inferior and varying quality of coals

Lower water requirement

Capability of phased construction and retrofitting


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IGCC TECHNOLOGY ...

Gasification of coal is the cleanest way of utilization of coal,while combined cycle power generation gives the highestefficiency.

Integration of these two technologies in IGCC powergeneration offers the benefits of very low emissions andefficiencies of the order of 44-48%.

The comparative indices show that in case of IGCC,emission of particulate, NOx and SOx are:

7.1%, 20% and 16%, respectively, of thecorresponding emissions from PC plant.


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IGCC ... Environmental performance of IGCC plants far exceeds that

of conventional and even supercritical plants.

Three major areas of technology that will contribute toimprovements in IGCC are :

hot gas de-sulfurisation

hot gas particulate removal

advanced turbine systems


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DEVELOPMENTAL GOALS FOR IGCC

To utilize Indias low grade coal for power generationwith improved plant efficiency.

To introduce coal gas in Natural Gas based Combined

Cycle Plants in a phased manner.

To increase power generation capacity at the level ofpresent emission.

To develop state of Art Technology for Indigenous andExport Markets.


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Gasifier

Raw GasCooler

CombustionChamber

Comp. Turb.

Alternator

Air

COAL

Ash

Exhaust

Gases

Condenser

WHB

Alternator

ST

Air

Fuel

Steam

GasClean Up

Booster

Steam

IGCC


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IGCC DEVELOPMENT PROGRAM IN INDIA

MAJOR MILE STONES:

Choice of gasification for high ash coals by BHEL 6.2 MW IGCC demonstration plant established by BHEL both with

Moving Bed and Fluidized Bed.

Coal Characterization by BHEL & IICT for gasification application.

Intensive data generated by IICT on oxygen-steam gasification in their

Moving Bed gasifier.

Task force CEA, CSIR, NTPC & BHEL constituted to assess

technological maturity & Financial requirement for a green field IGCC

plant of 100 MW capacity at Dadri (NTPC).

BHEL, CSIR & NTPC prepared proposal for setting up of this 100 MW

IGCC demonstration plant.


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Circulating Fluidized Bed Combustion(CFBC) technology has selectively beenapplied in India for firing high sulphur

refinery residues, lignite, etc.

CFBC Technology is superior to PC PowerPlant Technology:

Lower NOx formation and the ability tocapture SO2 with limestone injection thefurnace.

Circulating fluidized Bed Combustion


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Good combustion efficiencies comparable to PCPower Plants.

The heat transfer coefficient of the CFB furnace isnearly double that of PC which makes the furnacecompact.

Fuel Flexibility: The CFB can handle a wide range offuels such as inferior coal, washery rejects, lignite,anthracite, petroleum coke and agricultural wastewith lower heating.

Circulating fluidized Bed Combustion


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Steam to Super Heater

Cyclone

FurnaceCoal FeedHopper

Ash Cooler

Back-Pass

ESP

ExternalHeat-Exchanger

HP Air

Circulating Fluidised Bed Boiler

CFBC Vs Other Clean Coal


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CFBC Vs Other Clean CoalTechnologies

At present pulverized fuel firing with FGD are less costly

than prevailing IGCC technology. However, firing in CFB

Boiler is still more economical when using high sulfur lignite

and low-grade coals and rejects.

0.8-0.981.491.0Relative O&M

Cost/kW

1.15-1.421.03-1.191.0Relative CapitalCost/kW

41-4236.734.8Cycle Eff. %

IGCCPF+FGD/SCRCFBCITEM


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Renovation & Modernization (R&M) and LifeExtension (LE) of old power plants is a cost-effective option as compared to adding up greenfield plant capacities.

Growing environmental regulations would force

many utilities within the country to go forrevamping these polluting old power plants usingenvironmentally benign CFBC technology.


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Sustainable Power Development calls foradoption of Clean Coal Technologies like

Supercritical cycles, IGCC and FBCtechnologies

Supercritical Power technologies mayselectively be used for Pit Head powergeneration using washed coal

SUMMERY


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IGCC can revolutionize the power generationscenario in India, once the commercial viability oftechnology with high ash coals is established at the

proposed 100 MW plant.

The success of the project will largely depend onmaturity of Fluidized bed gasification technology for

high ash Indian Coals.

CFBC technologies are particularly useful for BoilerEmission reduction through revamping of old

polluting plants.

SUMMERY


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clean coal technologies for sustainability

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