Gasification Combined Cycles 101. Dr. Jeff Phillips EPRI

Transcription

1 Gasification Combined Cycles 101 Dr. Jeff Phillips EPRI

2 Outline What is coal? What is coal gasification? What is a combined cycle? What happens when we put them together? (IGCC) IGCC compared to other fossil fuel power generation options What s possible in the future (2020)? 2

3 Carbon Ash (rock) Sulfur Nitrogen Hydrogen Mercury Water 3

4 U.S. Coal Basins 4

5 Typical U.S. Coal Analysis (Coal Properties Differ Markedly) Pittsburgh #8 Illinois #6 Wyoming Texas Lignite Ultimate Analysis Moisture Carbon Hydrogen Nitrogen Chlorine Sulfur Oxygen Ash Higher Heating Value-as Received (Btu/lb) 13,260 10,982 8,340 6,010 5

6 What happens when coal burns? Carbon => CO 2 (carbon dioxide) Ash => flyash Sulfur => SO 2, SO 3 (SOx) Nitrogen => N 2 and NOx Hydrogen => H 2 O Mercury => Hg, HgCl 2 Water => water vapor (H 2 O) 6

7 What is gasification? Similar to combustion (burning) but with less than half the amount of oxygen needed to fully burn the coal Combustion: excess air Gasification: excess fuel (by a lot!!) 7

8 Combustion & Gasification Products 8

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13 Combustion vs Gasification Combustion Gasification Carbon CO 2 CO Hydrogen H 2 O H 2 Nitrogen NO, NO 2 NH 3 or N 2 Sulfur SO 2 or SO 3 H 2 S or COS 13

14 Combustion vs Gasification SO 2 & SO 3 is scrubbed out of stack gas reacted with lime to form gypsum NOx controlled with low NOx burners and catalytic conversion (SCR) H 2 S & COS are easily removed and converted to solid sulfur or sulfuric acid NH 3 washes out of gas with water, thermal NOx controlled by diluent injection in GT Large volume of flyash & sludge Hg can be removed by contacting flue gas with activated carbon Ash is converted to glassy slag which is inert and usable Hg removed by passing high pressure syngas thru activated carbon bed 14

15 Steam cycles vs Combined cycles Steam Cycles have a boiler a steam turbine Referred to as Rankine cycle, fossil boiler, fossil steam plant, conventional coal plant Combined Cycles have a Gas Turbine a heat recovery steam generator (HRSG) a steam turbine 15

16 Conventional Coal Plant 14 MW 41 % Efficiency (LHV basis) 86 MW 100 MW 41 MW 45 MW 16

17 Gas Turbine Photo source: Siemens 17

18 Gas Turbine simple cycle 100 MW 62 MW 38 MW 38% Efficiency (LHV basis) 18

19 Combined Cycle 22 MW 100 MW 40 MW 62 MW Fuel 19 MW 38 MW 21 MW to condenser = 57 MW 57% Efficiency! (LHV basis) 19

20 Combined Cycle Photo source: Siemens 20

21 100MW Net Coal to Power: = 42% (LHV basis) 9MW 21MW 26 MW 17MW 47MW 15MW 79MW 49MW 30MW IGCC schematic from US DOE 21

22 Existing Coal-based IGCCs Puertollano (Spain) Wabash (Indiana) Polk (Florida) Buggenum (Netherlands) 22

23 Other Notable US Gasification Plants: Dakota Gasification (lignite to SNG) Eastman Chemical (coal to chemicals) Coffeyville, KS Refinery (pet coke to ammonia fertilizer) Delaware City Refinery (pet coke to power) Negishi Oil Refinery IGCC Yokohama, Japan (gasifies asphalt residues) EPRI

24 Comparison to other fossil fuel options Emissions Greenhouse gases Cost of Electricity 24

25 Permitted & Actual IGCC NOx & SOx Emissions Proposed NSPS SOx limit 2.0 lb/mw-hr Lower GT firing temperature yields lower NOx Wabash has run a 30-day test with deep sulfur recovery in which SO2 emisssions averaged 0.27 lb/mw-hr Heavy oilbased IGCC with SCR Proposed NSPS NOx limit NOx - permit NOx - actual SOx - permit SOx - actual 0.0 Elcogas (SP) Nuon (NL) TECO Wabash Negishi (JP) Elm Rd Steelhead 25

26 PC Plant NOx & SOx Emissions Data Proposed NSPS SOx limit lb/mw-hr Proposed NSPS NOx limit NOx - permit NOx - actual SOx - permit SOx - actual Navaho 2 Intermountain 2 W A Parish 6 W A Parish 8 Elm Road Spruce 2 Comanche 3 Council Bluffs 4 Isogo 1 (JP) Isogo 2 (JP)

27 Emissions Comparison State-of-the-Art Coal Combustion, IGCC, and NGCC Values represent technology capability, not permit levels 0.8 Bituminous lb/mw-hr PRB NOx SO2 PM NGCC+SCR IGCC+SCR IGCC SCPC+SCR SCPC+SCR 27

28 Emissions Comparison with Older Coal Plants and Federal Standards lb/mw-hr NOx SO2 PM NGCC+SCR IGCC+SCR IGCC SCPC+SCR NSPS NSPS-proposed PC-old 250 US plants exceeded these levels in

29 Solid Waste Comparison (Based on nominal 500 MW plant size) Solid Waste, lb/mwh Pittsburgh #8 Illinois #6 Wyoming PRB TX Lignite Sulfur Spent Sorbent Ash/Slag PC- Sub PC- USC CFB IGCC PC- Sub PC- USC CFB IGCC PC- Sub PC- USC CFB IGCC PC- Sub PC- USC CFB IGCC 29

30 Makeup Water Comparison Makeup Water, gpm/mw PC CFB IGCC 30

31 CO 2 Emissions without CO 2 Capture 1,200 1,000 CO2 Emissions (kg/mw-hr) PC-Sub PC-Super PC-Ultra NGCC IGCC PC-old 31

32 IGCC with CO 2 Removal and Optional Hydrogen Co-Production Sulfur CO 2 to use or sequestration Coal Prep Gasification C + H 2 O = CO + H 2 Gas Cooling Shift CO+ H 2 O = CO 2 + H 2 Sulfur and CO 2 Removal O 2 N 2 Hydrogen Air Separation Unit Gas Turbine Air BFW Air Steam HRSG BFW Steam Turbine 32

33 Great Plains Synfuels Plant Uses water-gas shift and recovers CO 2 for enhanced oil recovery 105 MMSCFD Source: Dakota Gasification 33

34 FutureGen Project A 275 MW (nominal) IGCC with CO 2 capture and H 2 export Coal gasification followed by water-gas shift reaction 90% of CO 2 will be removed from syngas, compressed to circa 2000 psia and injected into deep saline aquifers for sequestration Remaining syngas will be primarily H 2 Small slipstream will upgraded to high purity H 2 and sold over the fence Rest will be fired in an advanced combined cycle Site selection RFP to be issued in March 2006 Operation targeted to begin in

35 Pulverized Coal (PC) with CO 2 Removal Fresh Water CO 2 to use or Sequestration Coal Air PC Boiler SCR ESP FGD CO 2 Removal MEA Flue Gas to Stack Steam Turbine Fly Ash Gypsum/Waste 35

36 CO 2 Capture Comparison Exhaust or Syngas Pressure CO 2 Volumetric Concentration CO 2 Partial Pressure Natural Gas Combined Cycle Exhaust Supercritical Coal Boiler Exhaust 14.7 psia 4% 0.6 psia 14.7 psia 13% 1.9 psia IGCC Syngas 825 psia 40% 330 psia 36

37 Impact of CO2 Capture Results from recent IEA & US DOE studies on bituminous coal adjusted to standard EPRI economic inputs, $2/MMBtu coal, 85% capacity factor, 2005 USD year Levelized Cost of Electricity, $/MWhr Range of Uncertainty Range of Uncertainty Delta for Capture Without Capture (Excludes cost of emission allowances and CO2 pipeline to sequestration site) 0 GE IGCC Shell IGCC SCPC-IEA SCPC-DOE 37

38 What s Possible in 2020? 38 38

39 What s Possible: IGCC without CO2 Capture Levelized Cost of Electricity, $/MWh IGCC w/o capture IGCC, w/o capture Cost of CO 2, $/metric ton 39

40 What s Possible: Pulverized Coal without CO2 Capture Levelized Cost of Electricity, $/MWh PC w/o capture PC w/o capture Cost of CO 2, $/metric ton 40

41 What s Possible: Comparison of IGCC and PC Levelized Cost of Electricity, $/MWh PC w/capture 2020 PC w/o cap 2020 IGCC, w/o cap 2020 IGCC w/capture Cost of CO 2, $/metric ton 41

42 The End