United States
                               Environmental Protection
                               Industrial Environmental Research
                               Research Triangle Park NC 27711
                               Research and Development
                               EPA-600/S7-82-028  August 1982
Project Summary
                               Pilot-Scale Assessment  of
                               Conventional  Particulate
                               Control  Technology for
                               Pressurized Fluidized-Bed
                               Combustion  Emissions

                               W. 0. Lipscomb III, S. R. Malani, C. L. Stanley, and S. P. Schliesser
                                This report presents the results of
                               a performance evaluation of con-
                               ventional particulate control tech-
                               nology applied to the EPA/Exxon
                               pressurized fluidized-bed combustion
                               (PFBC) mini plant in Linden, NJ. The
                               EPA mobile electrostatic precipitator
                               (ESP) and fabric filter pilot facilities
                               were slipstreamed downstream of
                               the miniplant's tertiary cyclone to
                               simulate the flue gas stream exiting
                               a PFBC combined-cycle gas turbine.
                               Results presented include control-
                               device operating characteristics and
                               performance based on mass and
                               fractional  efficiencies. ESP mass
                               efficiency  varied  from 80 to 90
                               percent and appeared to be sensitive
                               to miniplant operating conditions.
                               The mobile baghouse efficiency was
                               99.3 percent. The EPA mathematical
                               performance models for the ESP,
                               fabric filter, and venturi scrubber
                               were exercised to generate a basis
                               for an economic analysis of conven-
                               tional particulate control alternatives.
                               Costs of control for a 350 MW PFBC
                               ranged from 0.33 to 0.51 mills/kWh
                               for fabric filters and from 0.30 to 0.57
                               mills/kWh for ESPs. Venturi scrubbing
                               costs were  considerably higher (0.66
                                This Project Summary was developed
                               by EPA's Industrial Environmental
                               Research Laboratory, Research Triangle
                               Park, NC. to announce key findings of
                               the  research project that is fully
                               documented in a separate report of the
                               same title (see Project Report ordering
                               information at back).

                               Introduction and Objectives

                                Fluidized-bed combustion (FBC) sys-
                               tems being developed for steam and
                               electrical power generation and process
                               heating employ a number of concepts,
                               including atmospheric and pressurized
                               combustion, temperature control by
                               fuel-to-air ratio, heat transfer surface,
                               and particulate circulation. These FBC
                               systems offer attractive advantages
                               over conventional combustion in costs,
                               resource utilization, and environmental
                                Current FBC development programs
                               use calcium-based sorbents (limestones
                               and dolomites) for  in-situ control of
                               sulfur oxides (SOx) in the combustor,
                               while lower combustion temperatures
                               limit  to some degree the formation of
                               thermal nitrogen oxides (NOX). Particu-
                               late matter (PM) emissions from an
                               atmospheric FBC system are controlled
                               by conventional technology. In contrast,
                               the pressurized fluidized-bed combustion
                               (PFBC)  process uses the hot, high-
                               pressure flue gas exiting the combustor
                               to drive a gas turbine to generate
                               additional power, and  conventional

   technology for control of PM emissions
   is not applicable.
      There has been considerable discus-
   sion  of the degree of PM  removal
   required ahead  of  the  gas turbine to
   prevent excessive corrosion and/or
   erosion of the turbine.  High-pressure,
   high-temperature PM control technology
   (e.g., ceramic filters) has been investi-
   gated to provide a flue gas cleansed of
   PM to ensure acceptable turbine operating
   and maintenance costs and life expec-
   tancy. Recently, turbine designers have
   reduced the limitations on PM concen-
   tration and size distribution required so
   that  a  secondary  or tertiary cyclone
   system can achieve the required level of
   PM  control. The residual particulates,
   while acceptable for the gas turbine,
   must be further controlled  to meet
   environmental standards.
      This  study assessed a pilot-scale
   application of conventional PM control
   technology (i.e., an electrostatic precipi-
   tator (ESP) and a fabric filter (baghouse))
   to a PFBC cyclone-cleaned exhaust. The
   program's objectives were accomplished
   using EPA's mobile ESP and baghouse
   slipstreamed from the 630 kW EPA/Exxon
   Research and  Engineering Company
   miniplant in Linden, NJ.
      The mobile ESP pilot assessment was
   conducted during April and May 1979,
   and the mobile fabric filter program was
   accomplished in June 1979.
      Specific program objectives were to:
        Test the applicability of conventional
        PM control technology to cyclone-
        cleaned PFBC emissions.
        Evaluate respective control device
        operating characteristics  and  per-
        formance levels.
        Exercise EPA/IERL-RTP's control
        device performance models to esta-
        blish a basis for cost analysis.
             Generate cost-of-control estimates
             for an  ESP, a  baghouse, and a
             venturi  scrubber.
           Results presented in this report are
         specific to the EPA Exxon miniplant and
         the  slipstreamed mobile ESP and bag-
         house; extrapolation to other systems
         may be risky.

          The  study pointed to the following
            Conventional PM control technology
             appears applicable to cyclone-
             cleaned PFBC emissions.
            ESP operating characteristics and
             performance were influenced by
             PFBC operating conditions and
             sorbent  type. Cold-side  ESP perfor-
             mance  was  better than  hot-side
             performance on a normalized  gas
             treatment basis.
            Fabric filtration affords  an appreci-
             ably higher degree  of control at
             approximately the same costs as an
   This PFBC process  is apparently
    subject  to  peaking sulfur dioxide
    (SOzJ/sulfur trioxide (SOs) emission
    levels, which cause acid dew-point
    excursions and seriously impact
    control hardware specifications
    and operating conditions.
   There were both similarities and
    differences in conventional control
    device operating characteristics for
    the PFBC process and for conventional
    coal-fired boilers.

  Recommendations generated by the
study include:
   Conduct further pilot-scale control
    evaluations of the PFBC process to
    optimize control device design and
    operating conditions.
   Address the extent of and resolution
    of the apparent SOz/SOa excursions
    associated with this and  possibly
    other PFBC processes.
           W. 0. Lipscomb. Ill, S. R. Malani, C. L Stanley, and S. P. Schliesser are with
             Acurex Corporation, Morrisville, NC 27560.
           John O. Milliken is the EPA Project Officer (see below).
           The complete report, entitled "Pilot-Scale Assessment of Conventional Particu-
             late Control Technology for Pressurized Fluidized-Bed Combustion Emis-
             sions," (Order No. PB 82-230 921; Cost: $13.50, subject to change) will be
             available only from:
                   National Technical Information Service
                   5285 Port Royal Road
                   Springfield, VA 22161
                   Telephone: 703-487-4650
           The EPA Project Officer can be contacted at:
                   Industrial Environmental Research Laboratory
                   U.S. Environmental Protection Agency
                   Research Triangle Park, NC 27711
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