&ER&
United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
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
mills/kWh).
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
impact.
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
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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.
Conclusions
The study pointed to the following
conclusions:
• 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
ESP.
• 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
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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