NTPC_Technology Options for Higher Efficiency

8/8/2019 NTPC_Technology Options for Higher Efficiency

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D. K Jain

Executive Director (Engineering), NTPC Ltd.


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Overview of Indian power sector

Higher energy efficiency: Need and options Super critical and higher steam parameters

Gas turbine technology

R&M

IGCC Conclusion


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Installed Generation Capacity -140,302 MW (31.12.2007)

Electricity Generation- 660 BKwh (2006-07)

Per Capita Consumption-665 Kwh/Yr (2006-07) Shortages (Energy ~ 8.5%, Peak ~ 15%)

Per capita electricity consumption way below that of developedcountries. Rapid capacity expansion inevitable to sustain economicgrowth that hovers around 9% at present.


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!"#

1,700 4,60013,000

28,000

66,000

98,184

118,419

140,302

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

1950 1960 1970 1980 1990 2000 2005 Dec-07

Generating Capacity needs substantial enhancement to raise living standard


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!$

Generating Capacity (MW)(As on 31 Dec 2007)

64 %90,646Thermal

140,302

10,855

4,120

34,681

100 %TOTAL

8 %Renewable

3 %Nuclear

25 %HydroThermal : Fuel Mix (MW)

100.0%90,646Thermal

1.3%1,202Oil

16.2%14,692Gas

82.5%74,752Coal

Coal is main-stay of Indian power sector


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%

%

Dec, 07 Required by 2012

Generating CapacityGenerating Capacity

Source: CEA, [Ministry of Power, GOI

By 2012

Per capita consumption 1,000units

Installed capacity over 210,000MW

Spinning reserves 5%

Total rural householdelectrification by in next five years

Inter-regional transmissioncapacity 30,000 MW with NationalGrid in place

Energy efficiency/ conservation

Quality and reliable power supply

140,302 MW

212,000 MW


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&'(

Demand for power is growing with growth in economy Large capacity addition needed to meet the projected growth in

demand With tariff based bidding gaining ground, utilities have to bring

down their cost of generation to remain competitive

Increased emphasis on Environment and Clean Technologies CDM opportunities arising out of global warming concerns

Fuel, Land & Water availability becoming more and moredifficult

Efficiency enhancement feasible in future plants as well asexisting plants


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)

Up gradation and refinement of present technology

Pulverized Coal Power Plants

Higher steam parameters

Supercritical and Ultra Supercritical

Improvement in cycle configuration and turbine technology

Reduction in auxiliary power consumption

Combined Cycle Power Plants

Advanced class gas turbine Renovation &Modernization and up-rating

New Technologies

Integrated Gasification and Combined Cycle

Oxy-fuel Combustion


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*+

,

170 ata

5370 C

1945

5370

C

500 MW

130 ata

5370 C

1965

5370

C

200 MW to

250 MW

247 ata

5370 C

1900

5650 C

660 MW

130 ata

5350 C

2060 to 2190

5350

C

110 MW to

120 MW

70 to 90 ata

490 to 5350 C

2370

No Reheat

60 MW to

100 MW

60 ata

4800 C

2470

No Reheat

30 MW to

50 MW

1950s1950s

Turb Inlet Pressure/ Temp

Turbine Cycle Heatrate (kCal/kW-hr)

Reheat Temp.

Unit Size

1960s1960s 1970s1970s 19771977 19831983 UderUderConstrnConstrn..

PeriodPeriod

37.637.2 38.533 to 3530.529Gross efficiency (%)


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%

!"#$%$!&% '())*&

'())+ *&

!%&,

'())-

.())+ *&&

/0))12 3


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-.

/00!"*

39.438.537.837.6Gross Efficiency

1850190019321945Design Turbine

Cycle Heat Rate(Kcal/kW-hr)

593565565537IPT Inlet Temp (C)

565537537537HPT Inlet Temp (C)

247247170170HPT Inlet Pr(kg/cm2)

Super-CriticalSuper-CriticalSub-CriticalSub-CriticalTechnology

660/800 MW(UnderDevelopment)

660 MW(underconstruction)

500 MW New500 MW Old

While migrating to 800 MW, NTPC plant efficiency shall be comparable with those in thedeveloped countries


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~0.7~1~10.81~0.67~0.59Volatile/Fixed Carbon

11501200

1250

12501300

1350

12501300

1350

+1400Ash Fusion Temperature (C)

45-6540-5535-4566505550HGI

5400-

6200

5800-

6500

6200-

6400

3692660068006700Gross Calorific Value ,Kcal/kg (AD) %

252940-4545 approxFixed Carbon(AD) %

0.5-0.60.7 max0.9-1.00.50.70.70.7Sulphur (AD) %

30-4238-4439-452423-2825-3223-30Volatile Matter (AD) %

7-88 max12 max3815.015.015Ash Content (AD) %

10-1812 typical10 max2.0-3.52-42-4Inherent Moisture (AD) %

12-2520 max14 max9810.09Total Moisture (AR) %

Type CType BType A

INDONESIAIndian Coal(Dadri)

S AfricaChinaAustralia


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1+*

(

3 X 660

3 X 800

246/535/565

24

6/565/565

246/56

5/590

102.000

97.500

101.000

96.500

100.000

95.500

92.000

93.000

94.000

95.000

96.000

97.000

98.000

99.000

100.000

101.000

102.000

Cost/MW

UnitSize

SteamPa

rameters

Relative Cost / MW Vs Unit Size & Steam Parameters

246/535/565

246/565/565

246/565/590

Expected Cost / KW of 660 MW size units with 246/535/565 steam parameters = 100 (Base)


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*+

Deciding Factors: Furnace Size for Indian Coals

Experience of various manufacturers forlarge size furnace

Present Scenario: Indian coal - Operational experience for

500 MW and design experience for660MW

The furnace plan area for 800 MW and1000 MW size units for Indian coal - ofthe order of 415 m2 and 500 m2

respectively

Manufacturers have experience with amaximum furnace size of 400-450 m2

Thus 800 MW size and possibly 1000

MW for better coals may be the ultimateunit size with Indian coal at present.

400-450 m2(maximum)

Manufacturers

experienceworldwide

~500 m21000 MW withtypical Indian coal

~415 m2800 MW withtypical Indian coal

Furnace Size


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.%.%

GT Type & Size :D/E-Class, 90-100 MWDesign CC Efficiency (Net, LCV) :48.3%

Turbine inlet temperature :1000OC

CO2 Emissions :400 Kg/MWhr

NOx Reduction Tech. :Water Injection(upto100ppm)

Anta,

Auraiya,Kawas

Under

Induction

GT Type & Size :E-Class , 140 MW

Design CC Efficiency (Net, LCV) :50.3%



NOx Reduction Tech. :Water Injection (100 ppm)

GT Type & size :FA-Class , 250MW

Design CC Efficiency (Net, LCV) :55.5%



NOx Reduction Tech. :DLN Burner

Faridabad,

Kayamkulam-I,Gandhar-I


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-2!3

Plant performance optimizationGeneration maximization

Condition monitoring & R&M optimization throughcost benefit evaluation

Time based R&M

Pro-active R&MReactive R&M

Improve upon design efficiency-Use of higher cycle parameters to takeadvantage of recent metallurgical advancements

-State of the art turbine steam path design

Attain design efficiency

Uprating of capacityRestoration of lost capacity

Cost effective technology upgradesIn-kind replacement

Present FocusPast Focus


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4

+.

IGCC is gasification of coal and then

its use in combined cycle

Due to higher projected efficiency,suitability for carbon capture and ease

of capturing other pollutant IGCC is

promising technology.

With high natural gas prices andpressure for reduction of emission of

green house gases, IGCC with carbon

capture seem to be a favorable option

for fossil fuel based power generation


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5 $'+

Vacuum ResidueTexaco

(Now GE)

Commissioned: 1982

Expansion: 1976

Bharuch

LigniteWinklerCommissioned: 1963

Closed: 1979

Neyveli

CoalKopper-Tozek(Entrained Bed)

Commissioned: 1980Closed: 1999

Talcher

CoalKopper-Tozek

(Entrained Bed)

Commissioned 1980

Closed 1999

Ramagundam

FuelTechnologyCommissioningdate

Plant

Above gasifier were based on internationally available technologyNone of the coal and lignite based gasifier were successful with highash Indian coal and they have been decommissioned


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)3.

NTPC has carried out two feasibility studies on IGCC: one incollaboration with USAID and the other with an indigenousmanufacturer

Impediments to adoption of IGCC Low carbon conversion

Low cold gas efficiency

Plant efficiency lower than PC Plant

Requirement of a big cleaning system for gases carrying large amount ofhighly abrasive particulate matter

Inadequate experience with higher gasifier pressure

80 to 100% increase in capital cost w.r.t. to conventional plant

Relative inexperience with typical coal w.r.t. erosion and availability


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$'.'.

Oxy fuel combustion is use ofmixture of oxygen andrecycled CO2 in conventional

power plant Almost pure oxygen with two

third of total flue gas asrecycled gas will be used inPulverized Coal fired plant tokeep the flame temperaturesame as conventional plant

Thus flue gas is almost pureCO2 and hence ready forsequestration

Control of oxygen injectionpoint will help in NOx controlalso

Technology is in very early stages of development


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For Indian Coal, the PC fired plants with high cycle parameters are more efficient thanthe IGCC with current technology.

Adoption of higher parameters in super critical plants is the means for further efficiencyimprovement.

As we move to higher steam parameters for supercritical plants, the economic benefit,accruing due to lower fuel cost associated with higher plant efficiency, does not

compensate for the increased capital cost. To take advantage of the environmental benefits of higher cycle parameters without

jeopardizing affordability of power, the long term strategy is to reduce the cost of materialsuitable for high steam parameters.

IGCC technology need to be developed in the identified areas to make it suitable forIndian coals. However, suitable mechanism needs to be put in place to encourage andincentivise higher technological and financial investment in this development.

R&M and up-rating can go long way in improving the energy efficiency of old powerplants

Thus, for Indian thermal power sector, the options for efficiency improvements are: Adopt improved cycle parameters in new plants Develop IGCC further for Indian coal

Innovative R&M / up-rating of old plants to improve efficiency

Work on the technologies of the future such as oxy-fuel combustion, advanced cycles etc.


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6000C/6000C (eff = 39.9 %)

Base Efficiency=37.6 % (Gross, GCV)

5370C/5370C (eff = 38.2%)

5370C/5650C (eff = 38.5%)

5650C/5650C (eff = 38.8%)

Efficie

ncy

%

5370C / 5370C

170 246 316MS Pressure Kg/cm2

5650C/5930C (eff = 39.4%)

Efficiency figures corresponds to boiler efficiency of 85% on GCV basis


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'()31

Rs 810 Cr

(US$2-2.5 mn)

32 to 33 %

13-20%

37 to 40%

100 MW

IGCC

(Feasibility Study)

35 to 37 %35.336.2Net efficiency

(Typical)

Rs 79 Crores

(US$1.75-2.25 mn)

Rs 4.5 to 5.5 Cr

(US$1.13-1.38 mn)

Rs 4.5 to 5.5 Cr

(US$1.13-1.38 mn)

Capital Cost (PerMW)

13-20%5-6%5-6%Auxiliary Power

40 to 43%37.638.5Gross efficiency(Typical)

500 MW

IGCC

(Expected)

500 MW

Sub Critical

660 MW

Super Critical

Parameter

Capital Cost High due to cost of development, additional systems etc.


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2400-250022001000-1200Syngas GCVkCal/NM3

>99**>99%96*85 to 92%Carbon Conversion

75-83%**71.3%*72.5%*68-70%Cold gas efficiency

40.5**38.3*/39.7**35.4*/39**32-33%Net on GCVEfficiency

GE 6FA

U-Gas /BHEL

100 MW IndianIGCC

(Air blown)

GE 7FA

Texaco

Tampa***, Florida

(Oxygen blown)

V 94.2GE 7FAGT

ShellE-GasGasifier

BuggenumNetherlands

(Oxygen blown)

Wabas, Indiana

(Oxygen blown)

Plant

* DOE or other site ** Nexant Phase-A Report *** Climate in Florida is closer to India


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& Selection and design of gasifier is coal dependent

Entrained bed gasifier suitable for low ash and low moisture coal

Moving bed gasifier has not been used in IGCC. It is not good at handling

fines in coal. Tar and phenol are difficult to handle Fluidized bed gasifiers are limited to pilot scale. It is suitable for high ash

coal but present gasifiers are designed for high reactive coal

Penalty for cold gas cleanup is very high for air blown fluidized bedgasifier

Hot gas particulate cleaning, desulphurization and alkali cleaning is key toutilizing full potential of IGCC

These technology are still under development around the world

Gas turbine combustor are to be developed and tested for low Btu syngasfrom air blown fluidized bed gasifier. Alternatively enriched air operation

may be required.

High temperature Fluidized bed gasifier, Hot gas cleanup andLow BTU GT Combustor are required for Indian Coal based IGCC

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NTPC_Technology Options for Higher Efficiency