Control of Mercury Emissions by Injecting Powdered Activated Carbon (PAC)

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Control of Mercury Emissionsby Injecting
Powdered Activated Carbon (PAC)
Presentation to Utility MACT Working Group May
13, 2002 EPA, RTP, NC
Michael D. Durham, Ph.D., MBA ADA Environmental
Solutions 8100 SouthPark Way B-2 Littleton, CO
80120 303 734-1727
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Outline

• ADA-ES DOE/NETL Hg Control Program
• Background on PAC Injection Technology
• Results from PAC with an ESP
• Results from PAC with a FF
• Conclusions and Future Plans

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ADA-ES Hg Control Program

• Full-scale field testing of sorbent-based mercury
  control on non-scrubbed coal-fired boilers
• Primary funding from DOE National Energy
  Technology Laboratory (NETL)
• Cofunding provided by
• Southern Company
• Wisconsin Electric
• PGE NEG
• EPRI
• Ontario Power Generation
• TVA
• First Energy
• Kennecott Energy
• Arch Coal

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Project Overview

• Perform first full-scale evaluations of mercury
  control on coal-fired boilers (up to 150 MW
  equivalent).
• Evaluate effectiveness of sorbent-based Hg
  control (activated carbon).
• Test several different power plant
  configurations.
• Document all costs associated with Hg control.

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DOE/NETL Test Sites
Test Site Coal Particulate Test Control Dates A
labama Power Bituminous HS ESP Spring Gaston
COHPAC FF 2001 Wisconsin Electric PRB Cold Side
ESP Fall Pleasant Prairie 2001 PGE
NEG Bituminous Cold Side ESP Summer Brayton
Point 2002 PGE NEG Bituminous Cold Side
ESP Fall Salem Harbor 2002
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Coal-Fired Boiler with Sorbent Injection and
Spray Cooling
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Semi-Continuous Mercury Analyzer
Heater
Dry Air
CVAA
Flue Gas
Chilled Impingers
Gold Trap
Mass Flow Controller
Micro controller with Display
Waste
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Sampling Time Required
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Comparison of OH and S-CEM, Long Term Tests (10
lbs/MMacf)
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Capture of Vapor Phase Hg by Solid Sorbents

• Mass Transfer Limits (getting the Hg to the
  sorbent)
• Removal increases with particle concentration
• Produces percentage removal independent of
  concentration
• Particle control device (FF vs ESP) is a critical
  parameter
• Sorbent Capacity to hold Hg depends upon
• Sorbent characteristics
• Temperature
• Mercury concentration
• Concentrations of SO3 and other contaminants

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Equilibrium Adsorption Capacities at
250FUpstream and Downstream of SO3 Injection
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WEPCO Pleasant Prairie

• Testing completed fall of 2001
• PRB coal
• ESP only
• Spray cooling
• SO3 conditioning system

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(No Transcript)
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Activated Carbon Storage and Feed System
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ESP Configuration, PPPP
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Powdered Activated Carbon Injection System
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Baseline Hg Measurements (?g/dscm)
Location Particle Bound Oxidized, Hg2 Elemental, Hg0 Total, Hg
Inlet 99 0.16 2.29 6.21 8.65

Inlet 01 1.84 2.34 11.39 15.55

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Mercury Trends Week 1
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Response Time for PAC Injection on an ESP
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Carbon Injection Performance on a PRB Coal with
an ESP
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Long Term Trend Data
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Speciated Mercury Measured by Ontario Hydro
Method (10 lbs/MMacf)
(microgram/dncm)
PARTICULATE ELEMENTAL OXIDIZED TOTAL Baseline
ESP Inlet 1.97 12.22 2.51
16.71 ESP Outlet 0.01 9.80
6.01 15.82 Removal Efficiency 99.5
19.8 -139.3 5.3
PAC Injection ESP Inlet 0.98
14.73 1.73 17.44 ESP Outlet
0.00 4.27 0.44 4.71 Removal
Efficiency 100.0 71.0 74.5
73.0
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Alabama Power E.C. Gaston

• Alabama Power Company E.C. Gaston Electric
  Generating Plant Unit 3, Wilsonville, AL
• 270 MW Firing a Variety of Low-Sulfur, Washed
  Eastern Bituminous Coals
• Particulate Collection System
• Hot-side ESP, SCA 274 ft2/1000 acfm
• COHPAC baghouse supplied by Hamon
  Research-Cottrell
• Wet Ash Disposal to Pond

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Site Test Configuration with EPRI TOXECON at
Alabama Power Plant Gaston
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S-CEM Duct Traverse
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Example of S-CEM Data
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Response Time of PAC Injection with a Fabric
Filter
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Mercury Removal vs. Injection Rate
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Pressure Drop Increase from PAC Injection
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Mercury Removal vs. Injection Rate
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5-Day Continuous Injection
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Average Mercury Removal Long-Term Tests Gaston,
Ontario Hydro
(microgram/dncm)
PARTICULATE OXIDIZED ELEMENTAL TOTAL Baseline
COHPAC Inlet 0.09 9.54 5.97
15.60 COHPAC Outlet 0.01 11.19
3.34 14.54 Removal Efficiency
89.1 -17.3 44.1 6.8
PAC Injection COHPAC Inlet 0.23
6.37 4.59 11.19 COHPAC Outlet
0.12 0.91 0.03 1.05 Removal
Efficiency 45.6 85.7 99.3
90.6
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Comparison of Sorbent Costs for a Fabric Filter
and an ESP
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Conclusions (PAC General)

• PAC injection can effectively capture elemental
  and oxidized mercury from both bituminous and
  subbituminous coals
• Additional field tests and long-term
  demonstrations are necessary to continue to
  mature the technology
• Fabric filters provide better contact between the
  sorbent and mercury than ESPs resulting in higher
  removal levels at lower sorbent costs
• New COHPAC FFs will have to be designed to
  handle higher loadings of PAC to insure high
  (gt90) mercury removal
• Conventional FFs should not require any
  modifications for PAC

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Conclusions (Response to Concentration Variations)

• Response times to changes in inlet
  concentrations
• Feedback data from outlet CEMstens of minutes
• Impact of changes in injection rate tens of
  minutes to hours
• Long averaging times will be required to recover
  from upsets
• Injection at somewhat higher rates will make the
  technology more capable to handle inlet
  fluctuations
• PAC injection lends itself to the use of feed
  rate parameters as a definition of Maximum
  Achievable Control Technology

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Future Plans

• Short-term testing at additional sites
• PGE Brayton Point (Bituminous coal, large ESP)
  6/ 2002
• PGE Salem Harbor (Bituminous coal, SNCR, large
  ESP) 9/2002
• TBD (PRB coal, small ESP) 3/2003
• Southern Company (Bituminous coal, small
  ESP) 8/ 2003
• Long-term testing
• Alabama Power (Bituminous coal, COHPAC
  FF) 2002-2003
• CCPI Program (PRB Coal, COHPAC FF) 2004-2006
• CCPI Program (Bituminous Coal, COHPAC
  FF) 2004-2006
• Proposed

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For More Information

• www.adaes.com
• www.adaes.com/mercury.htm
• Link to other mercury related web sites
• Publications/reports
• www.adaes.com/MercuryPublic.htm
• Public information on DOE/NETL Mercury Control
  Program
• www.netl.doe.gov/products/environment/index.html
  DOE/NETL Website