The Cost of Mercury Removalfrom Coal-Based IGCC Relative to a PC PlantM.D. Rutkowski, M.G.Klett, R.C. MaxwellGasification Technologies 2002October 27- 30, 2002San Francisco, CaliforniaGasification Technologies Public Policy WorkshopAcknowledgmentsU.S. Department of EnergyNational Energy Technology LaboratoryEastman Chemical CompanyGasification Technologies Public Policy WorkshopBackgroundEPA Announced It Will Regulate Mercury and Other Air Toxicsfrom Coal-Burning Utilities•Two EPA reports to Congress (1997-1998)•Mercury is toxic of greatest concern•Coal-fired plants largest source of mercury•43 tons of mercury per yearGasification Technologies Public Policy WorkshopBackgroundProposed EPA Regulations to Control Mercury Emissionsfrom Coal-Burning Utilities•Regulations to be proposed by December 2003•Regulations to be promulgated by December 2004•Utility compliance by December 2007Gasification Technologies Public Policy WorkshopMercury Removal fromConventional Power PlantsBased on 1997 EPA Report to Congress•Activated carbon injection with and withoutspray cooling•Activated carbon bed•90% removal from stack gas•$1.43/MWh to $3.10/MWh•$17,400/lb Hg to $37,800/lb Hg•Amounts to nearly 10% of COEGasification Technologies Public Policy WorkshopThe Eastman Chemical Approach•Eastman has been removing vapor phasemercury for 20 years•Activated carbon beds•Located upstream of AGR process•Bed changeout every 18 to 24 months•90 to 95% mercury removal•~20-second gas residence time in vesselGasification Technologies Public Policy WorkshopTennessee Eastman, Kingsport, TNGasificationAreaGasificationAreaEASTMANEASTMANGasification Technologies Public Policy WorkshopChemicals from Coal – Final ProductsAcetic AnhydrideAcetic AcidAcetic AnhydrideAcetic AcidCoalCoalAcetic AnhydrideAcetic AcidAcetic AnhydrideAcetic AcidCoalCoalEASTMANEASTMANGasification Technologies Public Policy WorkshopEnvironmentally Friendly Process•Sulfur removal is > 99.9% (with Rectisol)•Eastman has a patented sulfur-free startupprocess (available for license)•NOx is not an issue with chemical productionoperations•Eastman has practiced vapor-phase mercuryremoval from syngas since initial plant startupEASTMANEASTMANGasification Technologies Public Policy WorkshopEastman Vapor-Phase Mercury Removal ProcessWaterRod Mills1300 ton/dayCoalSlurryPumpSlagScrubberOxygenSteamShift Reaction:CO + H2O CO2 + H2SteamDry Shifted GasDry Unshifted GasHg RemovalHg RemovalPreheatingGasifierNGQuench WaterBlowdown, Clarification,And RecycleWaterRod Mills1300 ton/dayCoalSlurryPumpSlagScrubberOxygenSteamShift Reaction:CO + H2O CO2 + H2SteamDry Shifted GasDry Unshifted GasHg RemovalHg RemovalSteamShift Reaction:CO + H2O CO2 + H2SteamDry Shifted GasDry Unshifted GasHg RemovalHg RemovalShift Reaction:CO + H2O CO2 + H2SteamDry Shifted GasDry Unshifted GasHg RemovalHg RemovalPreheatingGasifierNGQuench WaterBlowdown, Clarification,And RecycleEASTMANEASTMANGasification Technologies Public Policy WorkshopVapor-Phase Mercury Removal Processand Performance•Sulfur-impregnated activated carbon beds•~30°C and 900-1000 psig dry syngas feed•~15-20 seconds contact time (based on totalpacked volume)•>90-95% mercury removal (based on RadianInternational study)•>12-18 month lifetime of carbon beds (limitedby pressure drop or shift catalyst changeouts, not mercury breakthrough)EASTMANEASTMANGasification Technologies Public Policy WorkshopMercury Removal BedsEASTMANEASTMANGasification Technologies Public Policy WorkshopMercury Removal BedEASTMANEASTMANGasification Technologies Public Policy WorkshopActivated Carbon to Remove Mercuryfrom IGCC•Calgon type HGR granules•Best temperature is 100°F•No moisture condensation•Sulfided carbon•Adsorbs and converts Hg to HgS•Stable compound for landfill or recoveryGasification Technologies Public Policy WorkshopMercury Removal from IGCC•Syngas at high pressure•Low volumetric gas flow•Moderate temperatures•Particulate-free•Moderate humidityGasification Technologies Public Policy WorkshopFlow Diagram Showing Locationsfor Mercury RemovalFuel GasCooling &KnockoutMercuryRemovalMDEAUnitGas TurbineCombustor410°FFuel GasScrubberCOSHydrolysis103°FSourWaterStripperTexacoGasifier &Fuel GasCoolingASUClausPlantTail GasTreatmentUnitHRSGVent Gas Claus PlantOxidantCoalWaterAir toASU450°FSlagSour WaterWaterRecycle toGasifierClaus PlantOxidantVent Gas toIncineratorStack Gas280°FFlue Gas1131°FSulfurAcid GasGasifierOxidantFuel GasCooling &KnockoutMercuryRemovalMDEAUnitGas TurbineCombustor410°FFuel GasScrubberCOSHydrolysis103°FSourWaterStripperTexacoGasifier &Fuel GasCoolingASUClausPlantTail GasTreatmentUnitHRSGVent Gas Claus PlantOxidantCoalWaterAir toASU450°FSlagSour WaterWaterRecycle toGasifierClaus PlantOxidantVent Gas toIncineratorStack Gas280°FFlue Gas1131°FSulfurAcid GasGasifierOxidantGasification Technologies Public Policy WorkshopMercury Removal Process Design•250 MW net IGCC plant•Texaco radiant cooler gasifier•GE 7FA gas turbine•80% plant capacity factor•Mercury removal located upstream of AGR•20-second gas residence time•Low humidity gas•103°F operating temperatureGasification Technologies Public Policy WorkshopActivated Carbon Bed Design17 tons/yearCarbon replacement rate25 tonsInitial carbon charge0.4%Carbon loading, mercury5 ppbwMercury concentration outlet52 ppbwMercury concentration inlet10 psiPressure drop through bed378 psiaOperating pressureTwo vessels, 7.3 ft diameter x20.2 ft highCylindrical bed configurationGasification Technologies Public Policy WorkshopMercury Removal Cost Basis$7,446/yearO&M labor$59,242/yearOther O&M costs$36,792/yearPower penalty$320,683/yearTotal O&M$217,203/yearCarbon @ $6.43/pound$125,153/yearCapital recovery @ 15%$834,350 ($3.34/kW)Total capital cost$101,75025% contingency$122,100Indirects$203,500Installation$407,000Purchased equipmentGasification Technologies Public Policy WorkshopCost of Mercury Removal$3,412/lbMercury, $/lb131 lb/yearMercury reduction, lb/year$0.254/MWhTotal $/MWh$445,836/yearTotal $/yearGasification Technologies Public Policy WorkshopCompared with Conventional Power Plantsusing Carbon Beds$37,800/pound$3,412/poundCost of removal, $/pound~ 9%< 1%Fraction of COE$3.10/MWh$0.254/MWhCost of removal, $/MWh1601.0Relative volumetric gas flowStack gasSyngas ahead of AGRRemoval locationGasification Technologies Public Policy WorkshopSensitivity to Capital Cost FactorSensitivity of Key Parameters on Mercury Removal Costs$0.000$0.050$0.100$0.150$0.200$0.250$0.300$0.350$0.4001Relative Capital CostFactor = 0.5, 1.0, 2.0

Cost of Mercury Removal, $/MWhGasification Technologies Public Policy WorkshopSensitivity to Carbon CostSensitivity of Key Parameters on Mercury Removal Costs$0.000$0.050$0.100$0.150$0.200$0.250$0.300$0.350$0.4001Relative Carbon Cost Factor = 0.5, 1.0, 2.0

Cost of Mercury Removal, $/MWhGasification Technologies Public Policy WorkshopSensitivity to Carbon Life FactorSensitivity of Key Parameters on Mercury Removal Costs$0.000$0.050$0.100$0.150$0.200$0.250$0.300$0.350$0.400$0.4501Carbon Replacement Time (months) = 9, 18, 36

Cost of Mercury Removal, $/MWhGasification Technologies Public Policy WorkshopAmount of Mercury RemovalSensitivity of Key Parameters on Mercury Removal Costs$0.000$0.050$0.100$0.150$0.200$0.250$0.300$0.350$0.400$0.4501Amount of Mercury Removal (%) = 90, 99+

Cost of Mercury Removal, $/MWhGasification Technologies Public Policy WorkshopConclusions•The cost of mercury removal from anIGCC plant is reduced by locating thecarbon bed in the pressurized syngas stream.•This stream is characterized as havinga greatly reduced volumetric gas flowrelative to that of stack gas by a factorof nearly 200 for the same size plant.•The size of equipment, number of beds, and consequent costs are much lessthan treating for mercury removal in the stack gas of a PC or IGCC plant.•The estimated cost of $0.254 per MWhand $3,412 per pound of mercury from anIGCC plant is shown to be significantlylower than costs of mercury removalfrom PC power plants.•The capital cost estimate of $3.34 per kW for removal from the IGCC plantrepresents less than 0.3 percentof the total IGCC plant capital.•The small increase in cost of electricity of $0.254 per MWh due to adding themercury removal system represents an increase in the overall cost of electricityfrom the plant of less than 1 percent.