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					     Update on Full-Scale
Activated Carbon Injection for
Control of Mercury Emissions

             Presentation to
      Utility MACT Working Group
              August 8, 2002
             Washington D.C.
         Michael D. Durham, Ph.D., MBA
         ADA Environmental Solutions
            8100 SouthPark Way B-2
              Littleton, CO 80120
                  303 734-1727
Outline

    ADA-ES DOE/NETL Hg Control Program
    Summary of Previous Results from PAC
     with a FF and an ESP
    Preliminary results from Brayton Point
    Conclusions and Future Plans
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
    –   We Energies
    –   PG&E NEG
    –   EPRI
    –   Ontario Power Generation
    –   TVA
    –   First Energy
    –   Kennecott Energy
    –   Arch Coal
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.
Coal-Fired Boiler with
Sorbent Injection
           Sorbent
           Injection




                                   Hg
                                   CEM
                       ESP or FF




                         Ash and
                         Sorbent
  DOE/NETL Test Sites
Test Site             Coal       Particulate     Test
                                  Control       Dates
Alabama Power      Bituminous     HS ESP        Spring
Gaston                           COHPAC FF       2001
We Energies           PRB       Cold Side ESP    Fall
Pleasant Prairie                                 2001
PG&E NEG           Bituminous   Cold Side ESP   Summer
Brayton Point                                    2002
PG&E NEG           Bituminous   Cold Side ESP    Fall
Salem Harbor                                     2002
Description of Typical Test Plan
Tests are conducted in three distinct phases:
  – Baseline: Document mercury concentration at
    several locations with no ACI
    » Ontario Hydro and S-CEM
  – Parametric: A series of 8 hr. tests at different
    parametric conditions (sorbent, feedrate,
    operating conditions)
    » 3 weeks:   S-CEM only
  – Long-term: Ten day run at constant conditions
    using optimum sorbent and feedrate
    » Ontario Hydro and S-CEM
Semi-Continuous Mercury Analyzer

 Status: Manual operation; data every ten minutes
                             Dry Air           Heater


Flue Gas
            Chilled                                      CVAA
           Impingers

                                          Gold Trap


                                                        Mass Flow
                                                        Controller
                       Micro controller
                        with Display
                                                                     Waste
      Response Time for PAC
      Injection on an ESP
                      16                                          40
Total Hg (µg/dNm3 )




                                                                       lbs/Mmacf Sorbent
                                              ESP Inlet
                      12                                          30

                       8                                          20
                                                  ESP Outlet

                       4                                          10

                       0                                          0
                       6:00   10:00   14:00      18:00    22:00
Alabama Power E.C. Gaston Unit 3

   270 MW Wall Fired Boiler
   Particulate Collection System
     –   Hot-side ESP, SCA = 274 ft2/1000 acfm
     –   COHPAC baghouse supplied by Hamon
         Research-Cottrell
   Washed Eastern low-sulfur bituminous
    coal
     –   11,902 Btu/lb
     –   1.2% S
     –   14.7% ash
     –   0.14 ppm Hg
     –   0.017 % Cl

   Baghouse Temperature: 250-270 oF
  Site Test Configuration at Alabama
  Power Plant Gaston
                              Sorbent
                              Injection

                                              COHPAC


              Electrostatic
Coal          Precipitator




                                          Fly Ash (2%) + PAC
         Fly Ash (98%)
Mercury Removal vs. Injection Rate


                 100
  % Hg Removal




                 80
                                                 FGD
                 60                              PAC20
                                                 HydroC
                 40                              FGD 2
                                                 FGD3
                 20                              Fine FGD
                                                 OH Avg.
                  0
                       0          2          4              6

                       Injection Concentration (lb/MMacf)
Ontario Hydro Measurements at Gaston

                        (microgram/dncm)
                      PARTICULATE   OXIDIZED   ELEMENTAL TOTAL
Baseline (no ACI)
 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%
       5-Day Continuous Injection

                          25
           Hg (µg/Nm3)




                                                                            Ontario Hydro
                          20
                                             Total Inlet
                          15
                          10
                           5
                                                                  Total Outlet
                           0
                               4/22   4/23                 4/24          4/25                4/26      4/27
                         300                                                                               12
Boiler Load (MW)




                                                                                                                Inj. Conc. (lb/MMacf)
                         250                                                                               10
                                                                                Load
                         200                                                                               8
                         150                                                                               6
                         100                                                                               4
                                                                     Sorbent Injection Concentration
                          50                                                                               2
                           0                                                                               0
                            4/22      4/23                 4/24         4/25                4/26       4/27
Misleading Short-Term Test

                100
 % Hg Removal




                80
                                                FGD
                60                              PAC20
                                                Insul
                                                HydroC
                40                              FGD 2
                                                FGD3
                20                              Fine FGD
                                                 OH Avg.
                                                Insul 1
                 0
                      0          2          4              6

                      Injection Concentration (lb/MMacf)
We Energies Pleasant Prairie Unit 2

   600 MW Turbo Charged Boiler
   Particulate Collection System
     – Cold-side ESP, SCA = 468 ft2/1000
       acfm
     – Wahlco SO3 System
   Powder River Basin, subbituminous
     – 8,385 Btu/lb
     – 0.3% S
     – 5.1% ash
     – 0.11 ppm Hg
     – 0.0008 % Cl
   ESP Temperature: 290 oF
Carbon Injection Performance on a
PRB Coal with an ESP
                                                                   FGD
                80
                                                                   FGD humid
                70                                                 FGD(g)
                60                                                 FGL
                                                                   FGD, no SO3
 % Hg Removal




                50                                                 FGD(g), no SO3
                40                                                 Insul
                                                                   Long Term Tests
                30                                                 Ontario Hydro
                20

                10

                 0
                     0   10        20         30        40    50
                         Injection Concentration (lb/MMacf)
Speciated Mercury Measured by
Ontario Hydro Method (10 lbs/MMacf)

                        (microgram/dncm)
                       PARTICULATE   ELEMENTAL OXIDIZED   TOTAL
Baseline (no ACI)
 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%
PG&E NEG Brayton Point Unit 1

   245 MW Tangential Boiler
   Particulate Control System
    – Two ESPs in series with combined
      SCA of 559 ft2/kacfm
    – EPRICON SO3 system
   Eastern low-sulfur bituminous
    coal
    – 12,319 Btu/lb
    – 0.7 % S
    – 11% ash
    – 0.03-0.05 ppm Hg
    – 0.1-0.4 % Cl
   ESP Temperature: 280-340 oF
Sampling Locations
                       #2
                                    #3             #4
                            Stack
      #1    East
#0



             Old ESP
             Old ESP                     New ESP
APH
APH
Sampling Locations

                              Sorbent
                 Location 3   Injection
                                     Location 2

    Location 4                              Location 1
Variability of Baseline (no ACI)
Mercury Removal at Brayton Point
Five sets of Ontario Hydro measurements have
  been made since 1999 documenting baseline
  mercury removal
 The coal specification for the West Virginia low-
  sulfur bituminous coal has been the same during
  this time period
 Measured variability:
      Mercury in coal: 0.03-0.08 ppm
      Chlorine in coal: 0.08-0.4 %
      Mercury in flue gas: 2.9-6.4 ug/m3
      Percent of mercury
       (as oxidized or particulate): 89-95%
    Removal        across ESP: 30-91%
Preliminary Results with ACI from
S-CEM Measurements at BP
                      100



                      80
Mercury Capture (%)




                      60



                      40                      Different symbols
                                              represent different
                      20                      sorbents or operating
                                              conditions
                       0
                            0   5        10          15         20    25

                                    Injection Rate (lb/MMacf)
Mercury Removal Trends with ACI

                        100
                                      Gaston
  Mercury Removal (%)



                                                               Brayton Point
                         80

                         60
                                                                PPPP
                         40

                         20

                          0
                              0   5      10      15       20       25      30
                                  Injection Concentration (lb/MMacf)
           Mass Transfer is a
           1st Order Rate Equation

                     1.6
                     1.4       Gaston
-Log(Hg Remaining)




                     1.2                                         Brayton Point
                     1.0
                     0.8
                     0.6
                     0.4
                                                                 Pleasant Prairie
                     0.2
                     0.0
                           0   5        10     15       20       25      30         35
                                         Injection Rate (lb/MMacf)
Differences in Coal and Flue Gas
Characteristics for the Three DOE Sites

                    Pleasant     Gaston        Brayton
                     Prairie                    Point
Coal                     PRB     Washed      Eastern Bit.
                                Eastern Bit.

Mercury (ppm)            0.11       .14          0.03
Hg in Flue Gas (ug/m3)   17         15            1-3
Chlorine (ppm)            8         169        1000-4000
HCl (ppm)                1                       150
Reasons to be Cautious in Extrapolating
Preliminary Results from BP

    Bituminous coals present measurement
     challenges for S-CEMs

    Very low mercury concentrations in coal and flue
     gas (sorbent capacity and measurement issues)

    Unusual two ESPs in series configuration

    Exceptionally large ESP

    Documented variability in day to day performance
Spray Cooling and ACI
    At Pleasant Prairie, no improvement in mercury removal
     were observed when spray cooling by 50 oF
    Sorbents such as activated carbon have excess capacity
     and therefore are unlikely to benefit from spray cooling
    At Brayton Point, high levels of mercury removal were
     measured at ESP temperatures of 280-340 oF without
     cooling the gas
    Therefore, spray cooling should not be necessary for most
     applications of PAC injection
    May be beneficial when gas temperature is above 350 oF
     (i.e. lignite sites may require spray cooling)
Carbon-in-Flyash Issues

     Even small amounts of carbon in flyash can
      limit use as a cement admixture.
     If currently selling flyash, must address loss
      of sales and disposal
     Several developing technologies to address
      the problem:
      – Separation
      – Combustion
      – Chemical treatment
      – Configuration solutions such as TOXECON.
        Comparison of Sorbent Costs for
        a Fabric Filter and ESPs

                 100
                                 COHPAC FF Bit                   ESP Bit
Hg Removal (%)




                  80

                  60
                                                                ESP PRB
                  40

                  20

                   0
                       0   0.5       1       1.5     2    2.5        3     3.5   4
                                         Sorbent Costs (mills/kWh)
Conclusions
    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
    Coal characteristics appear to effect ACI performance
     with an ESP
Future Plans

 Short-term testing at additional sites
   –PG&E Salem Harbor (Bituminous coal, SNCR, large ESP)
                                                     9/2002

 Long-term testing
   – Alabama Power (Bituminous coal, COHPAC FF) 2002-2003
   –*CCPI Program (PRB Coal, COHPAC FF)         2004-2006
   –*CCPI Program (Bituminous Coal, FF)         2004-2006

 * Proposed

				
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