current and emerging mercury and multipollutant control ...€¦ · wet fgd modification 83 % of...

CURRENT AND EMERGING MERCURYCURRENT AND EMERGING MERCURYAND MULTIPOLLUTANT CONTROLAND MULTIPOLLUTANT CONTROL

TECHNOLOGIESTECHNOLOGIESICAC Forum '03:ICAC Forum '03:

Multi-Pollutant Emission Controls & StrategiesMulti-Pollutant Emission Controls & StrategiesOctober 14-15, 2003, Nashville, TNOctober 14-15, 2003, Nashville, TN

RaviRavi K. K. SrivastavaSrivastava, U.S. EPA, National Risk Management Research Laboratory,, U.S. EPA, National Risk Management Research Laboratory,Research Triangle Park, NC 27711Research Triangle Park, NC 27711James James StaudtStaudt, Andover Technology Partners, 112 Tucker Farm Rd., North Andover, MA, Andover Technology Partners, 112 Tucker Farm Rd., North Andover, MA0184501845E. E. Stratos TavoulareasStratos Tavoulareas, Energy Technologies Enterprises Corp., 1112 , Energy Technologies Enterprises Corp., 1112 TowlstonTowlston Rd., Rd.,McLean, VA 22102McLean, VA 22102Wojciech JozewiczWojciech Jozewicz and and Michiel DoornMichiel Doorn, ARCADIS , ARCADIS GeraghtyGeraghty & Miller, Research Triangle & Miller, Research TrianglePark, NC 27709Park, NC 27709

22

What We’ll Cover Today . . .What We’ll Cover Today . . .

Sources of mercurySources of mercuryRegulatory driversRegulatory driversMercury speciation andMercury speciation andcapturecaptureControl technologiesControl technologies

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Sources of MercurySources of Mercury

Top five anthropogenic sources (1999)Top five anthropogenic sources (1999)–– Utility coal - 47.9 tons (39.8%)Utility coal - 47.9 tons (39.8%)–– Industrial boilers - 12 tons (10%)Industrial boilers - 12 tons (10%)–– HWI - 6.6 tons (5.5%)HWI - 6.6 tons (5.5%)–– Chlorine production - 6.5 tons (5.4%)Chlorine production - 6.5 tons (5.4%)–– MWC - 5.1 tons (4.2%)MWC - 5.1 tons (4.2%)

Natural sourcesNatural sources–– Volcanoes - annual tonnage not quantifiedVolcanoes - annual tonnage not quantified–– Forest fires - annual tonnage not quantifiedForest fires - annual tonnage not quantified

44

Policy DriversPolicy DriversUtility MACTUtility MACT–– Maximum degree of emissions reduction achievable, taking in toMaximum degree of emissions reduction achievable, taking in to

consideration costconsideration cost–– At least as stringent as the best performing facilities for new sources;At least as stringent as the best performing facilities for new sources;

average of the top performing 12 percent for existing sourcesaverage of the top performing 12 percent for existing sources–– Emissions standard applicable to each sourceEmissions standard applicable to each source–– Section 112 does not allow trading between facilities to meet theSection 112 does not allow trading between facilities to meet the

standard; averaging among units at a given facility can be consideredstandard; averaging among units at a given facility can be considered

Clear SkiesClear Skies–– Emissions reductions from power plants: Emissions reductions from power plants: NOxNOx by 67 percent, SO2 by by 67 percent, SO2 by

73 percent, and mercury by 69 percent; to be phased-in between 2008-73 percent, and mercury by 69 percent; to be phased-in between 2008-2018; includes emissions cap and trade provisions2018; includes emissions cap and trade provisions

55

Policy DriversPolicy Drivers(Continued)(Continued)

PM Transport Rule: regulatory approach that usesPM Transport Rule: regulatory approach that usesexisting CAA mechanisms to address transportedexisting CAA mechanisms to address transportedair pollutionair pollution–– Analyze sources of SO2 (for PMAnalyze sources of SO2 (for PM2.52.5) and ) and NOxNOx (for PM (for PM2.52.5 and and

ozone).ozone).–– Determine whether there is a significant contribution fromDetermine whether there is a significant contribution from

individual states.individual states.–– Controls effective 2009/2010 at the earliest.Controls effective 2009/2010 at the earliest.–– EPA develops an emissions budget for each state. States haveEPA develops an emissions budget for each state. States have

discretion in deciding which sources to control to meet the budget.discretion in deciding which sources to control to meet the budget.–– Plan to propose an optional cap-and-trade program similar to AcidPlan to propose an optional cap-and-trade program similar to Acid

Rain and Rain and NOxNOx SIP call. SIP call.

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>2500 °C

Hg°

APCDInletEntrained PM

CO2

H2O

SO2

NOx

HCl N2 Hg

Coal

Mercury Speciation:

300 °F

Hgo, Hg2+ compounds, particulate mercury Hg(p)

Mercury in Coal-fired BoilersMercury in Coal-fired Boilers

Temperature, °C

Thermochemical Equilibrium Calculations

Hg°

HgCl2HgO

0 300 600 900 1200

Mas

s Fr

actio

n

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Mercury SpeciationMercury Speciation

In general, speciation depends on:In general, speciation depends on:–– Coal properties (mercury, chlorine, and ash contents)Coal properties (mercury, chlorine, and ash contents)–– Time/temperature profileTime/temperature profile–– Flue gas composition and fly ash characteristicsFlue gas composition and fly ash characteristics

(carbon, calcium, iron, porosity)(carbon, calcium, iron, porosity)– Flue gas cleaning conditions

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Mercury Capture in Existing EquipmentMercury Capture in Existing Equipment

Removal in PM ControlsRemoval in PM ControlsMercury can be adsorbed onto fly ash surfaces; HgMercury can be adsorbed onto fly ash surfaces; Hg2+2+ is ismore readily adsorbed than Hgmore readily adsorbed than Hg00

Mercury can be physically adsorbed at relatively lowerMercury can be physically adsorbed at relatively lowertemperatures (hot-side ESP vs. cold-side ESP)temperatures (hot-side ESP vs. cold-side ESP)

Capture in Wet ScrubbersCapture in Wet ScrubbersHgHg2+2+ capture depends on solubility of each compound; capture depends on solubility of each compound;HgHg00 is insoluble and cannot be captured is insoluble and cannot be capturedCapture enhanced by SCRCapture enhanced by SCR

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ICR DataICR Data

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0

20

40

60

80

100

Hg

Rem

oval

(%)

Bituminus�� Subbituminous • Bituminous Bituminous vsvs

subbituminous subbituminous

•• Hg capture for differentHg capture for different coal-control technology coal-control technology combinations correlate combinations correlate with coal chlorine content with coal chlorine content

•• No data on UBC content No data on UBC content of fly ash of fly ash

1010

Chlorine vs. Mercury SpeciationChlorine vs. Mercury Speciation

ICR data for HgICR data for Hg00

at ESP & FF inletat ESP & FF inlet

HgHg00 oxidation appears oxidation appearsto be independent ofto be independent ofchlorine above 100chlorine above 100µµg/gg/g

Other important factorsOther important factors–– TemperatureTemperature–– Fly ash carbonFly ash carbon0%

20%

40%

60%

80%

100%

10 100 1,000 10,000Coal Chlorine, ppm dry

%H

g0 a

t PC

D In

let

Cold-side ESP & FFHot-side ESP

1111

Impact of Carbon In AshImpact of Carbon In Ash

0%10%20%

30%40%50%60%70%

80%90%

100%

0 100,000 200,000 300,000 400,000 500,000

C:Hg Ratio

Hg R

emov

al A

cros

s ES

P

DeVitoPlant APlant BPlant C

Cold-Side ESP, bituminous coal

Hot-side ESP, bituminous coal

1212

Speciation influences emissions controlSpeciation influences emissions control–– Ionic HgIonic Hg2+2+ is removed easily by wet scrubbers is removed easily by wet scrubbers–– Volatile elemental HgVolatile elemental Hg00 is difficult to capture is difficult to capture

SCR units are being used extensively to meetSCR units are being used extensively to meetcurrent current NOxNOx regulations regulationsSCR can convert elemental mercury in coalSCR can convert elemental mercury in coalcombustion flue gas into the ionic formcombustion flue gas into the ionic form–– field data in Europe and U.S. reflects increase infield data in Europe and U.S. reflects increase in

HgHg2+2+ across SCR reactor across SCR reactor

SCR and Mercury InteractionsSCR and Mercury Interactions

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SCR-Mercury R&DSCR-Mercury R&DTested 4 utility plants in the 2001 and 2 in 2002; retested 2 plants in 2002;Tested 4 utility plants in the 2001 and 2 in 2002; retested 2 plants in 2002;total of 8 data pointstotal of 8 data pointsOxidized mercury increase across SCR: bit. - up to 71%; Oxidized mercury increase across SCR: bit. - up to 71%; subbitsubbit. - 10% (one. - 10% (onedata point only)data point only)Removal in PM control and FGD (5 data points) - ~ 85% - 90%Removal in PM control and FGD (5 data points) - ~ 85% - 90%Results from repeated tests were consistent with previous data; impacts ofResults from repeated tests were consistent with previous data; impacts ofSCR catalyst aging not apparentSCR catalyst aging not apparentSCR systems with relatively lower catalyst volumes (space velocity greaterSCR systems with relatively lower catalyst volumes (space velocity greaterthan 3500 hr-1) also showed significant oxidation increasesthan 3500 hr-1) also showed significant oxidation increasesData gaps: PRB, blendsData gaps: PRB, blendsOngoing EPA bench- and pilot-scale research:Ongoing EPA bench- and pilot-scale research: HClHCl provides critical chlorine provides critical chlorinesource for Hgsource for Hg00 oxidation; oxidation; NOxNOx has a significant promotional effect; has a significant promotional effect; SOSOxx has haslittle effect under the conditions of this studylittle effect under the conditions of this study

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Some Retrofit Control OptionsSome Retrofit Control OptionsPlants with ESP or FF: Plants with ESP or FF: sorbentsorbent injection; injection; sorbentsorbentinjection + pulse jet FF (PJFF); circulating fluid bedinjection + pulse jet FF (PJFF); circulating fluid bedabsorber (CFBA) on bit.-fired for SOabsorber (CFBA) on bit.-fired for SO22 and mercury and mercurycapturecapture

Plants with dry FGD systems:Plants with dry FGD systems:–– Bit. coal - small amounts of carbon, if neededBit. coal - small amounts of carbon, if needed–– SubbitSubbit. coal - . coal - sorbentsorbent injection or injection or sorbentsorbent injection + pulse jet FF injection + pulse jet FF

(PJFF); ; (PJFF); ; sorbentsorbent injection + FF (upstream of SDA) if injection + FF (upstream of SDA) ifneutralization of chlorine is a concernneutralization of chlorine is a concern

Plants with wet FGD systems: SCR; oxidation catalysts,Plants with wet FGD systems: SCR; oxidation catalysts,reagents, and other systemsreagents, and other systems

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Carbon Injection ProjectsCarbon Injection ProjectsAlabama Power E.C. Gaston: unit 3, 270-MW, low-sulfur eastern bit. coals (0.14Alabama Power E.C. Gaston: unit 3, 270-MW, low-sulfur eastern bit. coals (0.14ppmppm Hg and 160 Hg and 160 ppmppm ClCl); hot-side ESP, COHPAC ); hot-side ESP, COHPAC baghousebaghouse; testing on one-half of; testing on one-half ofthe gas stream, nominally 135 MW; wet ash to pondthe gas stream, nominally 135 MW; wet ash to pond

WEPCO Pleasant Prairie: unit 2, 600-MW, PRB coal (0.11 WEPCO Pleasant Prairie: unit 2, 600-MW, PRB coal (0.11 ppmppm Hg and 8 Hg and 8 ppmppm ClCl););ESP (468 ftESP (468 ft22//kacfmkacfm), spray cooling, SO), spray cooling, SO3 3 conditioning; testing on one ESP chamberconditioning; testing on one ESP chamber(1/4 of the unit); fly ash sold for use in concrete(1/4 of the unit); fly ash sold for use in concrete

PG&E PG&E BraytonBrayton Point: unit 1, 245-MW, low-S bit. coal (0.03 Point: unit 1, 245-MW, low-S bit. coal (0.03 ppmppm Hg and 2000-4000 Hg and 2000-4000ppmppm ClCl); SO); SO3 3 conditioning system; 2 conditioning system; 2 ESPsESPs in series (550 ft in series (550 ft22//kacfmkacfm); PAC injection); PAC injectionbetween the between the ESPsESPs

PG&E Salem Harbor: 85-MW, low-S bit. coal (0.03-0.08 PG&E Salem Harbor: 85-MW, low-S bit. coal (0.03-0.08 ppmppm Hg and 206 Hg and 206 ppmppm ClCl););ESP (474 ftESP (474 ft22//kacfmkacfm); SNCR); SNCR

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Mercury Removal Trends with ACIMercury Removal Trends with ACI

0

20

40

60

80

100

0 5 10 15 20 25 30Injection Concentration (lb/MMacf)

Mer

cury

Rem

oval

(%) Brayton Point

PPPP

Gaston

Source: ADA Environmental Solutions (2003)

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PG&E Salem HarborPG&E Salem Harbor(w/o PAC Injection)(w/o PAC Injection)

85-MW, low-S bit. coal (0.03-0.0885-MW, low-S bit. coal (0.03-0.08ppmppm Hg and 206 Hg and 206 ppmppm ClCl); ESP (474); ESP (474ftft22//kacfmkacfm); SNCR); SNCR

High baseline removal due to highHigh baseline removal due to highlevels of LOI; minimal impact onlevels of LOI; minimal impact onreducing LOI from 30-35% to 15-20%reducing LOI from 30-35% to 15-20%at 300 at 300 ooFF

Temperature has greater effect thanTemperature has greater effect thanLOILOI

SNCR has no impact on Hg removalSNCR has no impact on Hg removal 0

10

20

30

40

50

60

70

80

90

100

270 290 310 330 350 370

17-19% LOI (45 lb/M Macf)20-24% LOI (55 lb/M Macf)25-29% LOI (68 lb/M Macf)>30% LOI30-35% LOI, C1, High Load21-27% LOI, C2, High LoadLS bitum coal

Hg

Rem

oval

(%)

Temperature (oF)


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PG&E Salem HarborPG&E Salem Harbor(w/ PAC Injection)(w/ PAC Injection)

At lower temperatures,At lower temperatures,removal by PAC affected byremoval by PAC affected byhigh baseline removalhigh baseline removalAt higher temperatures, linearAt higher temperatures, linearbehavior (similar to that atbehavior (similar to that atBraytonBrayton Point Point

0

10

20

30

40

50

60

70

80

90

0 5 10 15 20 25

280-290 F298-306 F322-327 F343-347 F

Hg

Rem

oval

(%)

Injection Concentration (lb/106 acf)


1919

Cost of Control with Carbon InjectionCost of Control with Carbon Injection((Low-sulfur Bituminous Coal)Low-sulfur Bituminous Coal)

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0.00

0.50

1.00

1.50

2.00

2.50

3.00

40% 50% 60% 70% 80% 90% 100%

Total mercury removal (%)

mills

/kWh

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��975 MW, ESP

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975 MW, COHPAC

100 MW, ESP

100 MW, COHPAC

2020

Cost of Control with Carbon InjectionCost of Control with Carbon Injection((SubbituminousSubbituminous Coal) Coal)

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0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

40% 50% 60% 70% 80% 90% 100%

Total mercury removal (%)

mills

/kWh

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975 MW, ESP

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975 MW, COHPAC100 MW, ESP100 MW, COHPAC

2121

What is amultipollutant

controltechnology?

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MultipollutantMultipollutant Control Examples Control Examples

Electrocatalytic Electrocatalytic Oxidation (ECO)Oxidation (ECO)Advanced Dry FGD (several flavors)Advanced Dry FGD (several flavors)Plasma-enhanced ESP (PEESP)Plasma-enhanced ESP (PEESP)PahlmanPahlmanREACTREACTOzone-Based TechnologiesOzone-Based TechnologiesCoal BeneficiationCoal BeneficiationMany othersMany others

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MultipollutantMultipollutant Controls Controls

YYYYYYYYOzone-BasedOzone-Based

YYYYYYYYREACTREACT

YYYYYYYYPahlmanPahlman

YYYYYYNNPEESPPEESP

YYYYYYNNAdv Dry FGDAdv Dry FGD

YYYYYYYYECOECO

Fine PMFine PMHgHgSOSO22NOxNOxProcessProcess

2424

Wet FGD ModificationWet FGD Modification83 % of U.S.-installed FGD capacity83 % of U.S.-installed FGD capacityCapable of removing SOCapable of removing SO22 in excess of in excess of95 %95 %Can remove oxidized HgCan remove oxidized HgThree routes for NO removal:Three routes for NO removal:–– gas phase oxidation to Ngas phase oxidation to N22OO55

–– oxidation to NOoxidation to NO22 and reduction to N and reduction to N2 2 in thein thescrubber via sulfate and bisulfate ionsscrubber via sulfate and bisulfate ions

–– other processes (Mitsubishi and other processes (Mitsubishi and LextranLextran))

Investigate SO2, Hg, Investigate SO2, Hg, NOx NOx removal andremoval andSO2 to SO3 conversionSO2 to SO3 conversion

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Development of Development of Multipollutant SorbentsMultipollutant Sorbents

SorbentSorbent Development Development–– Synthesis,Synthesis,

Characterization,Characterization,Evaluation &Evaluation &OptimizationOptimization

–– Relate structure andRelate structure andchemical nature tochemical nature toadsorption characteristicsadsorption characteristics

0

20

40

60

80

100

120

140

160

Am

ount

Adsorb

ed

NO2 SO2 Hg

Pollutant

Capture Capacity of Various Sorbents

A-Clay

K-Clay

Act C

Lime

ox-CSH

NO2 and SO2 capacity given as mg/g adsorbed in 1 hr at 80˚C;

Hg0 capacity given as µg/g adsorbed in 1 hr at 80˚C

•Types of Sorbents Being Studied–Sorbents synthesized using industrial by-products–Modified carbon-type sorbents–Surface modified Calcium Silicate Hydrate (C-S-H)–Multipollutant sorbents that also have adsorptive capacity for CO2

current and emerging mercury and multipollutant control ...€¦ · wet fgd modification 83 % of...

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