1. Control of Mercury Emissions by 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

2. 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

3. 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
PG&E NEG
EPRI
Ontario Power Generation
TVA
First Energy
Kennecott Energy
Arch Coal

4. 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.

5. DOE/NETL Test Sites Test Site Coal Particulate Test Control Dates
Alabama Power Bituminous HS ESP Spring
Gaston COHPAC FF 2001
Wisconsin Electric PRB Cold Side ESP Fall
Pleasant Prairie
PG&E NEG Bituminous Cold Side ESP Summer
Brayton Point
PG&E NEG Bituminous Cold Side ESP Fall
Salem Harbor

6. Coal-Fired Boiler with Sorbent Injection and Spray Cooling
Ash and Sorbent
ESP or FF
Hg CEM
Spray Cooling
H2O
Air

7. Semi-Continuous Mercury Analyzer
Heater
Dry Air
CVAA
Flue Gas
Chilled
Impingers
Gold Trap
Mass Flow
Controller
Micro controller
with Display
Waste

8. Sampling Time Required

9. Comparison of OH and S-CEM*, Long Term Tests (10 lbs/MMacf)

10. 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

11. Equilibrium Adsorption Capacities at 250°F Upstream and Downstream of SO3 Injection

12. WEPCO Pleasant Prairie
Testing completed fall of 2001
PRB coal
ESP only
Spray cooling
SO3 conditioning system

14. Activated Carbon Storage and Feed System

15. ESP Configuration, PPPP
Spray Cooling
Carbon Injection

16. Powdered Activated Carbon Injection System

17. 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

18. Mercury Trends Week 1

19. Response Time for PAC Injection on an ESP

20. Carbon Injection Performance on a PRB Coal with an ESP

21. Long Term Trend Data

22. Speciated Mercury Measured by Ontario Hydro Method (10 lbs/MMacf)
(microgram/dncm)
PARTICULATE ELEMENTAL OXIDIZED TOTAL
Baseline
ESP Inlet
ESP Outlet
Removal Efficiency % % %
PAC Injection
ESP Inlet
ESP Outlet
Removal Efficiency % % % %

23. 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

24. Site Test Configuration with EPRI TOXECON at Alabama Power Plant Gaston
Sorbent Injection
COHPAC
Fly Ash (2%) + PAC
Coal
Fly Ash (98%)
Electrostatic
Precipitator

25. S-CEM Duct Traverse

26. Example of S-CEM Data

27. Response Time of PAC Injection with a Fabric Filter

28. Mercury Removal vs. Injection Rate

29. Pressure Drop Increase from PAC Injection

30. Mercury Removal vs. Injection Rate
PAC Rate Limit Due to Pressure Drop

31. 5-Day Continuous Injection

32. Average Mercury Removal Long-Term Tests Gaston, Ontario Hydro
(microgram/dncm)
PARTICULATE OXIDIZED ELEMENTAL TOTAL
Baseline
COHPAC Inlet
COHPAC Outlet
Removal Efficiency % % % %
PAC Injection
COHPAC Inlet
COHPAC Outlet
Removal Efficiency % % % %

33. Comparison of Sorbent Costs for a Fabric Filter and an ESP

34. 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 FF’s will have to be designed to handle higher loadings of PAC to insure high (>90%) mercury removal
Conventional FF’s should not require any modifications for PAC

35. Conclusions (Response to Concentration Variations)
Response times to changes in inlet concentrations:
Feedback data from outlet CEMs—tens 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

36. Future Plans Short-term testing at additional sites Long-term testing
PG&E Brayton Point (Bituminous coal, large ESP) 6/ 2002
PG&E 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)
*CCPI Program (PRB Coal, COHPAC FF)
*CCPI Program (Bituminous Coal, COHPAC FF)
* Proposed

37. For More Information www.adaes.com www.adaes.com/mercury.htm
Link to other mercury related web sites
Publications/reports
Public information on DOE/NETL Mercury Control Program
DOE/NETL Website