Advanced Coal Power Plant Water Usage

Transcription

1 CoalFleet for Tomorrow Advanced Coal Power Plant Water Usage Ronald L. Schoff Project Manager Advanced Coal Generation Options Charlotte, North Carolina July 8 9, 2008 CoalFleet for Tomorrow is a registered service mark of Electric Power Research Institute, Inc.

2 U.S. Forecasts Largest Coal Generation Capacity Installation in 40 Years Capacity Added (GWs) U.S. Coal Capacity Additions, Capacity Addition Levels Not Seen in 40 Years Industry Growth Trend Not Seen in 50 Years 20 Year Market Trough Source: U.S. Department of Energy NETL & Annual Energy Outlook

3 Coal Technology Options w/o CO 2 Capture (Approximate data, current technologies) NSPS = New Source Performance Standards PC = Pulvervized Coal SCPC = Supercritical PC USPC = Ultra-Supercritical IGCC = Integrated Gasification NGCC = Natural Gas Efficiency (HHV Basis) PRB Bit. NSPS PC Fleet Average 33% SCPC (1050 F Steam) w/ SCR 37% 38% USPC (1100 F Steam) w/ SCR 38% 39% IGCC (CoP E-Gas) w/ SCR 38% 39% NGCC (GE 7FB) w/ SCR 50% Regulated SO 2 lb/mw-hr NO X lb/mw-hr Particulate lb/mw-hr <0.3 <0.5 < <0.3 <0.5 <0.2 <0.1 <0.2 <0.1 nil 0.1 nil Mercury % Reduction -- ~36% 80% 80% 90% -- Non- Regulated CO 2 lb/mw-hr Water Usage gal/mw-hr , ,950 1, ,900 1, ,850 1, Relative Emissions Profiles for PC and IGCC are Very Low. 3

4 Overview Water enters gas path in coal as moisture and hydrogen Gasification-produced syngas contains H 2 and H 2 O H 2 O is condensed prior to combustion and is recoverable Combustion products contain only H 2 O H 2 O is contained in flue gas to the atmosphere 80% or more of water use in an advanced coal plant is Cooling Water Condenser duty has the greatest impact on Cooling Water flow Cooling water temperature has a direct impact on Power Output need to keep it low while reducing water usage 4

5 Integrated Gasification Combined Cycle (w/o CO 2 Capture) Sulfur Separation Tail Gas Recycle Sulfur Recovery Unit Oxygen Coal Gasifier Syngas Cooler or Quench Filter COS Hydrolysis Syngas Cooling & Hg Removal Acid Gas Removal Unit Acid Gas Slag Particulates Syngas Diluent (N 2 ) Water Clean Fuel Gas Reheat/ Humid. Extraction Water In Water Out Fuel Gas Coal H 2 O Flue Gas Coal H 2 Condensation AGR Solvent CT Evaporation CT Blowdown Gas Turbine HRSG Steam Turbine Raw Water 5

6 IGCC Plant Overview Current IGCC Plants contain 2 trains of equipment to produce ~780 MWe of gross power output 70% of auxiliary power required is from intercooled compressors (~110 MWe at ISO) Increasing CW temperature by 20 F increases power demand by ~5% for compressors 1 Hga increase in Condenser backpressure can reduce gross power by ~5% There are significant financial drivers to maintaining low CW temperature while reducing water losses, thus usage 6

7 Integrated Gasification Combined Cycle (w/ CO 2 Capture) Sulfur Separation Steam Tail Gas Recycle Sulfur Recovery Unit Oxygen Coal Gasifier Syngas Cooler or Quench Filter Water Gas Shift Syngas Cooling & Hg Removal Acid Gas / CO 2 Removal Unit Acid Gas Slag Particulates CO 2 Syngas Diluent (N 2 ) Water CO 2 Comp. Extraction Water In Water Out Fuel Gas Reheat/ Humid. Clean Fuel Gas CO 2 To Pipeline Coal H 2 O Flue Gas Coal H 2 Condensation CT Evaporation Gas Turbine HRSG Steam Turbine AGR Solvent CT Blowdown Raw Water 7

8 IGCC Plant Overview Addition of CO 2 Capture Water gas shift reactors included to convert CO to CO 2 for removal; also convert H 2 O to H 2 More H 2 to gas turbine increases emissions of H 2 O at stack and reduces recoverable condensed water Increased coal demand to meet GT needs increases water usage incrementally by ~5% Reduction in net MWe from plant impact the specific water usage more than actual water usage, which is driven mostly by gross MWe, not net MWe 8

9 Pulverized Coal Combustion (w/o CO 2 Capture) Limestone Slurry Activated Carbon Baghouse / ESP FGD Flue Gas To Stack ID Fans SCR Fly Ash Evaporation & Blowdown Losses Gypsum Secondary Fans Pulverized Coal Boiler Steam Turbine / Condenser Cooling Tower Water In Coal H 2 O Water Out Flue Gas Primary Fans Pulverized Coal Power Makeup Water Coal H 2 Gypsum CT Evaporation LS Slurry CT Blowdown Bottom Ash Raw Water 9

10 PC Plant Overview All power in a PC plant comes from the Steam Turbine Condenser duty is higher per net MW for PC than IGCC, as a result Water usage is higher for PC as a consequence FGD and Wet ESP can have further impact on water use 10

11 Pulverized Coal Combustion (w/o CO 2 Capture) Limestone Slurry Activated Carbon Baghouse / ESP FGD CO 2 Capture Flue Gas To Stack ID Fans Secondary Fans SCR Pulverized Coal Boiler Fly Ash Steam Turbine / Condenser Gypsum Evaporation & Blowdown Losses Cooling Tower CO 2 CO 2 Compressor Water In Coal H 2 O Water Out Flue Gas Primary Fans Power Makeup Water Coal H 2 Gypsum Pulverized Coal CT Evaporation Bottom Ash LS Slurry CT Blowdown Raw Water 11

12 PC Plant Overview CO 2 Capture Flue gas needs to be cooled prior to CO 2 capture, which normally results in installation of a direct contact cooler Some water may be recoverable CO 2 capture system condenses ~50% of LP steam for solvent reboiling, which reduces condenser duty Additional cooling demand imposed by CCS system (solvent cooling, primarily) Specific water usage is much higher than non-capture due to high level of power loss in CO 2 capture system Actual water usage may go up 10-20%, but not as much as specific water usage implies Note: Oxyfuel combustion depends on separation of CO 2 and H 2 O in a flue gas condenser this technology could be used to recover water from all coal power cycles 12

13 IGCC, PC & NGCC Plant Water Loss Comparison gal/mwh gal/mwh Water Loss, Gal/Mwh gal/mwh gal/mwh 452 gal/mwh gal/mwh gal/mwh E-Gas Shell GE R-C GE Quench NGCC PC Sub PC Super Process Losses Flue gas losses Cooling water losses 13

14 IGCC, PC & NGCC Plant Water Loss Comparison Raw Water Usage (gpm/mwnet) IGCC IGCC w/co2 USCPC USCPC w/co2 NGCC NGCC w/co2 14

15 Advanced Coal Power Plants EPRI Program Options EPRI CoalFleet for Tomorrow Program (P66): Accelerating deployment of advanced coal technologies: IGCC Ultra-supercritical PC (>1100ºF) Supercritical Circulating Fluidized-Bed Oxyfuel Combustion Fostering development of IGCC CO 2 capture capability/ convertibility. EPRI CO 2 Capture and Storage (P165): Accelerating development of advanced post-combustion CO 2 capture technology (PC plants). Understanding issues and demonstrating security of CO 2 storage from fossil generation. 15

16 Questions and Discussion 16