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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%
Turbine inlet temperature :1100OC
CO2 Emissions :390 Kg/MWhr
NOx Reduction Tech. :Water Injection (100 ppm)
GT Type & size :FA-Class , 250MW
Design CC Efficiency (Net, LCV) :55.5%
Turbine inlet temperature :1320OC
CO2 Emissions :350 Kg/MWhr
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