United States
Environmental Protection
Agency
Office of
Reseach and
Development
Industrial Environmental Research
Laboratory
Research Triangle P.~'k. North Carolina 27711
EPA-600/7-77-013
February 1977
EPA AND ERDA
HIGH-TEMPERATURE/
HIGH-PRESSURE PARTICULATE
CONTROL PROGRAMS
Interagency
Energy-Environment
Research and Development
Program Report
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S.
Environmental Protection Agency, have been grouped into seven series.
These seven broad categories were established to facilitate further
development and application of environmental technology. Elimination
of traditional grouping was consciously planned to foster technology
transfer and a maximum interface in related fields. The seven series
are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series. Reports in this series result from
the effort funded under the 17-agency Federal Energy/Environment
Research and Development Program. These studies relate to EPA's
mission to protect the public health and welfare from adverse effects
of pollutants associated with energy systems. The goal of the Program
is to assure the rapid development of domestic energy supplies in an
environmentally—compatible manner by providing the necessary
environmental data and control technology. Investigations include
analyses of the transport of energy-related pollutants and their health
and ecological effects; assessments of, and development of, control
technologies for energy systems; and integrated assessments of a wide
range of energy-related environmental issues.
REVIEW NOTICE
This report has been reviewed by the participating Federal
Agencies, and approved for publication. Approval does not
signify that the contents necessarily reflect the views and
policies of the Government, nor does mention of trade names
or commercial products constitute endorsement or recommen-
dation for use.
This document is available to the public through the National Technical
Information Service, Springfield, Virginia 22161.
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EPA-600/7-77-013
February 1977
EPA AND ERDA
HIGH-TEMPERATURE/HIGH-PRESSURE
PARTICULATE CONTROL PROGRAMS
by
R.A. Kennedy, H. Dhillon, and J.B. Truett
The Mitre Corporation
Metrek Division
McLean, Virginia 22101
Contract No. 68-01-3539, Task 4
Program Element No. EHE623
EPA Project Officer: Dennis C. Drehmel
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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FOREWORD
The U.S. Environmental Protection Agency (EPA) and the U.S. Energy Research
and Development Administration (ERDA) are engaged in research and development on
methods for removal of particulate matter from gases at elevated temperature and
pressure. Success in this endeavor is important for reasons of health and ecology,
for protection of process equipment, and for energy conversion efficiency. Some
of the advanced energy processes have excellent environmental potential. Development
of these processes is especially dependent on solution of the particulate problem.
This document, describing the related EPA and ERDA programs, is part of the effort
to affect interagency coordination in. the continuing development work.
iii
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ABSTRACT
This report describes and compares current projects sponsored by .the U.S.
Environmental Protection Agency (EPA) and the .U.S. Energy Research and Develop-
ment Administration (ERDA), relating to the control of particulate matter in
fuel gas streams at high temperatures (1000 to 2000 F) and high pressures
(5 atmospheres and greater).
The purpose of the description is to document each project indicating the
sponsor, contractor, funding, project officer,1 duration, milestones, and to
provide a narrative statement of objectives and the -technology involved. Project
descriptions are intended to provide a basis for identifying any overlap or dupli-
cation and to indicate .areas which are not addressed by either Agency. Description
of these projects was obtained from documentation provided by the two Agencies
and from discussions with Agency contractor representatives.
The project descriptions and the discussion of possible overlap or omissions
which follow is organized to consider particulate control in the three categories
of: (1) particulate characterization and aerosol mechanics,, ,(2) instrumentation
and measurement, and (3) control technology development. Conclusions and recom-
mendations are reached .regarding the questions of overlap and omissions, and the
general subject ,of interagency -coordination. Introductory material reflects the
respective roles of EPA .and ERDA and the rationale and options relating to parti-
culate control through hot ;gas cleanup at .elevated pressure.
The overall .effort for control of •particulate matter at high temperatures
and pressure includes four proj-ects sponsored by ERDA and eight projects sponsored
by EPA.
Comparison of the EPA and .ERDA .activities for possible overlap and omissions
is summarized in the '.conclusions .which indicate that there is little evidence of
any 'overlap
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CONTENTS
Disclaimer ....... ii
Foreword ••' iii
Abstract iv
Tables .-..'. - vi
1. Introduction 1
2. Conclusions 11
3. Recommendations 14
4. ERDA Projects .; . . 15
5. EPA Projects . 31
6. Comparison of ERDA and EPA Programs 48
References and Bibliography • 51
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TABLES
Number Page
1 Typical Turbine Specifications , 10
2 ERDA High Temperature/Pressure Projects 16 •
3 EPA High Temperature/Pressure Projects 32
VI
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SECTION 1
INTRODUCTION
The U.S. Environmental Protection Agency (EPA) and the U.S. Energy Research
and Development Administration (ERDA) are both engaged in research and development
on methods for removing particulate matter from fuel and combustion gas streams
at nigh temperatures ( 1000 to 2000 F) and pressures ( 5 atmospheres and higher).
However, the primary orientation of the two agencies' programs differ significantly.
EPA's principal interests are to insure that human health and the environ-
ment are adequately protected from the adverse effects of particulate emissions,
and that technological methods are available for controlling such emissions to
acceptable levels. From EPA's standpoint, such control technology does not
necessarily have to operate at conditions of high temperature and pressure (HTP),
although HTP operation may be more efficient and more economical.
One of ERDA's principal interests in particulate removal from hot pressurized
gases relates to the capability of using such gases (produced by gasification or
combustion of coal and other solid fuels) to drive turbines and other equipment
without introducing the large thermal inefficiencies attendant to cooling and
depressurizing the gas for particulate removal at ambient temperatures prior to
combustion. If the particulate-laden gas stream enters a gas turbine without
particulate removal, the resultant decrease in turbine blade life would probably
adversely affect the economics of operation. Another of ERDA's primary interests
is insuring that the exhaust gas from the turbine and other combustion processes
meets emission standards for particulate matter.
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1.1 EPA Involvement in HTP Particulate Removal
EPA's work on HTP particulate removal is part of its R&D program for :parti-
culate control. The overall program includes assessment of the effects of pollu-
tants on human health and welfare; development of technological measures for
controlling the release of environmental pollutants; and monitoring and controlling
of the release of particulate matter into the environment. Since a major portion
of man-made particulate pollutants are associated with energy conversion and
utilization facilities, EPA has focused its attention mainly on steam/electric
power plants '(among the various stationary sources of atmospheric pollutants)
and on the automobile (among mobile sources). The present report 'deals only with
stationary sources.
The current emission standards for fuel combustion facilities are. expressed
as pounds of particulate matter per million Btu of heat input. The current
emission limit from new stationary sources is 0.1 pound of particulate matter
per million Btu of thermal energy released by combustion processes. The ambient
air standard is imposed in terms of the concentration of "total suspended parti-
culate" per cubic meter of air. Although the size distribution of the particulate
is not reflected in these standards, the health and environmental effects of
particulate pollutants are related to the size distribution as' well as the chemical
composition of the particulate. Very fine particles can by-pass: the body's
respiratory filters and may produce adverse health effects by penetrating deep
into the lungs. Small particles (0.1 to ly in size) also reduce the atmospheric
visibility. In view of these characteristics of small particles, EPA is considering
the establishment of standards for fine particulate emissions and ambient concen-
tration.
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Earlier EPA work has demonstrated that particulate removal to meet existing
emission standards for combustion processes can be accomplished by application
of available equipment to exhaust gases under the moderate temperatures and
pressures at the stack (end-of-system cleanup). EPA recognizes, however, that
particulate removal can be performed, partially if not totally, within the energy
conversion system, and that within-system cleanup may be accomplished with greater
efficiency and less expense than end-of-system cleanup. Such within-system parti-
culate removal may be performed with the gas stream at high temperature and
pressure, or at high pressure and reduced temperature. One objective of EPA's
Particulate Control Program is to identify effective combinations of these three
approaches to particulate control: removal at HTP, removal at high pressure and
low/moderate temperatures, and removal at the moderate end-of-system temperatures
and pressures.
The requirements of improved thermal efficiency and equipment protection
have caused ERDA to concentrate on the monitoring and control of particulate at
high temperatures and pressures. The success of these efforts can be expected to
reduce the requirements of control technology at the exhaust end of the gas turbines.
At this time, cyclones, electrostatic precipitators, and fabric filters are being
used effectively for removing particulate from gas streams at low to moderate
temperatures and pressures. However, the control equipment has to handle very
large volumes of gases at reduced temperatures and pressures. This consideration
is a major incentive for EPA's efforts in the area of HTP particulate control
technology. In addition, the use of HTP clean-up systems would eliminate the
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problems of recovery of specific cor.-.pounds that could be combusted in the process
to form non-parti'culate pollutants. These compounds include tars and oils
(high sulfur), ammonia, hydrocarbons, phenols, etc.
EPA's interest in particulate pollutants is motivated by the undesirable
effects of particulate matter on the environment- However, EPA recognizes that
any steps taken to reduce the concentration of particulate in fuel gas streams
within the fuel processing and utilization cycles will result in the minimization
of the cleanup effort needed at the point of release into the atmosphere. The
interrelation between in-process cleanup and end-of-system cleanup forms the
basis for coordination between the particulate control activities of EPA and
ERDA.
1.2 ERDA's: Involvement in HTP Particulate Removal
A major element in ERDA's mission is to enhance the utilization of domestic
fuel resources. Toward' this end', ERDA has undertaken extensive programs for
producing synthetic fuel gases through the utilization of gasifiers and power
generation by fluidized bed combustors. Innovative advanced power systems (combined
gas-steam turbine cycles, etc.) are being developed for efficient utilization of
these systems. It is very desirable to maintain the pressure and temperature of
the fuel or combustion gas stream at high levels (pressures up to 1000 psig and
temperature upto 2000 F). Despite significant improvements iri the' synthetic gas
production' process,- it is probable that the synthetic fuel gas from most of the
production processes will contain some suspended particles of various sizes.
The equipment utilizing this fuel or combustion gas at high temperature and pres-
sure is generally a gas turbine. Excessive concentrations of particulate tend to
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damage the blades of the turbine through erosion, corrosion and deposition. The
efficiency of the turbine could decrease as a result of this damage. Although
the size range, concentration, and velocity of particles that cause turbine
damage have not been established conclusively, particles larger than 2 microns (y)
in size appear to be more harmful than smaller particles.
It is possible to clean up the fuel gas stream adequately at moderate
temperature and pressure by using the existing control technology for low
temperature/pressure operation. Lowering the temperature and pressure of the
fuel gas stream lowers the thermal efficiency of the system. Moreover, the
volume of gas increases when the pressure is decreased. Therefore, the require-
ments of high termal efficiency, gas turbine protection, and the possibility
of cleaning a smaller volume of gas make it very attractive to employ control
technology that operates efficiently at high temperature and pressure.
1.3 Presentation and Categorization of EPA and ERDA Activities
The objective of this report is to review the ongoing and planned activities
of EPA and ERDA pertaining to HTP particulate control, and to determine any overlaps
between these activities. Since EPA and ERDA are operating relatively independently,
it is entirely possible that there may be some problem areas which are not addressed
by either Agency. A number of such instances are identified in this report.
Recognizing the potential benefits of high temperature/pressure particulate
clean-up, each Agency has undertaken RD&D efforts in this area. ERDA's activities
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are generally ancillary to its efforts- deal-ing with the development of gas-if-ier.s'
and f-luid-lzed1 bed> combustors'. EPA has initiated a- few maj.or efforts concentrating
exclusively on the development and demonstration of high temperature/pressure
particulate clean-up technology.
The overall program for R&D in the high temperature/pressure particulate
clean-up covers three major sub-areas. These are:
(1) Particulate characterization and aerosol mechanics (physical and
chemical properties, particle collection mechanisms);
(2) Measurement and instrumentation (for observing mass and volume concen-
tration,, particle size distribution, and particle velocity)' for high
temperature/pressure operation; and
(3) Control technology (particulate removal devices) for operation in
high temperature/pressure gas streams.
The ERDA and EPA activities are discussed in terms of these categories in
Sections 4.0 and 5.0 of this report. The rationale for the selection of. these
three activity categories is presented' in the subsections immediately following.
1.3.1 Particulate' Characterization'.and Aerosol .Mechanics
A- comprehensive' knowledge of the physical and chemical characteristics of
particul'ate at high temperature and- pressures is essential for developing
effective measurement instruments and particulate removal equipment under these
conditions.
Since ERDA's major incentive for the control of particulate at HTP is
associated' with the: protection of equipment receiving, the- part"icle-l'oaded; gas
streams, the1 maj'or emphasis in ERDA programs is placed on the prevention of
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damage to turbines and other equipment by particulate matter. Nevertheless,
the need for protecting the environment is also germane because of present
or future standards for particulate emissions. It is possible that stringent
New Source Performance Standards may be established for the emissions of fine
particulate. Some of these particulates may be the result of reactions in the
turbine which produce secondary particulate. In addition, the constituents of
the fine particulate (too small to be considered harmful to turbines) may include
hazardous materials such as lead, mercury and arsenic.
The preceding remarks highlight the need for comprehensive characterization
of the particulate content of fuel gas streams at high temperature and pressure.
This characterization will involve statements concerning the particle size distri-
bution, the chemical content of particles and the identification of gaseous com-
ponents which can be expected to transform into secondary particulate either in
the turbine, in the heat recovery and exhaust system, or after the exhaust gases
are released to the atmosphere.
Characterization of the aerosol will provide an indication of the magnitude
of the HTP particulate problem in terms of (1) the potential damage to the power
generation equipment through erosion, corrosion, and deposition; and (2) the
expected impact on air quality of the particulate emissions from the power
generation system, and the resultant effect on human health, the ecology, and
esthetics. A detailed knowledge of the magnitude and the nature of the HTP
particulate control problem can be significant in the development of an
effective control strategy for preventing equipment damage and evironmental
quality deterioration while maintaining high energy conversion efficiency.
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In the ^context of effectiveness of control technology, it is important to
study the mechanics of particulate behavior under conditions involving high
temperatures and -pressures. Physical properties such as resistivity of particles,
and phenomena involving thermal ionization and reentrainment need to -be more
completely understood in order to optimize the utilization of the .particulate
control technologies.
The need for characterization of particulate at high temperatu-r.e and pressure
did not arise.-until particulate control under these conditions became a 'necessity
on account of advanced power systems. EPA has already undertaken significant
efforts dealing with measurement instrumentation and control technology develop-
ment for particulate at HTP. However, the activities pertaining to the charac-
terization .of particulate under these conditions have not gained momentum.
1.3.2 Measurement and Instrumentation
In the development of .direct combustion systems involving -gas turbines, it
is important to undertake -real-time monitoring and analysis of the particles in
the f-uel gas stream to -record the mass loading (or volumetric loading) and the
size distribution of the particles entering the gas turbine at .high temperature
and pressure. An evaluation of -the performance of HTP .particulate cont-rol-tech-
nology also requires a reasonably accurate measurement of the -par-t-ioulate loading
and size distribution ;at the inlet and .outlet of the control equipment.
In the vicinity of the turbine inlet, pressures as high as 500 psi and
temperatures ranging from 1000 F to 2000 F can be encountered. In such severe
conditions, 'mechanical devices such as hot wire anemometers either fail quickly
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or become inaccurate vrith the passage of time. Instruments utilizing mechanical
sampling techniques perturb the volume being monitored, and affect accuracy of
measurement.
The measurement methods used for collection of fractional efficiency data
are based on various procedures including inertial impaction, optical counting,
condensation nuclei counting and diffusion batteries. Because of the severe
conditions associated with high temperature/pressure particulate control equipment,
techniques other than the optical counters are not very effective in measuring
equipment efficiency.
1.3.3 Control Technology
Although no specific standards have been set for allowable particulate loadings
for gases used for driving gas turbines, it is generally agreed that the lifetine
and performance efficiency of gas turbines can be increased by reducing the parti-
culate content of the gas stream (particulate larger than 2y are considered more
harmful than smaller particles). As an example, some typical particulate loading
specifications are listed in Table 1. Electrostatic precipitators (ESP), scrubbers,
and fabric filters have been successfully used for removing particulate from exhaust
gases at moderate levels of temperature and pressure, but not under HTP conditions.
Lowering the temperature and pressure of the turbine inlet gas stream for the purpose
of facilitating particle removal by using proven techniques would result in a large
loss of energy. Therefore, it is highly desirable that the particulate removal be
carried out at high temperatures and pressures in order to maintain high thermal
efficiency of the fuel conversion processes (coal gasifiers,FBC, etc.).
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TABLE 1. TYPICAL TURBINE SPECIFICATIONS
Turbine Manufacturer
Particulate Loading
(Maximum Allowable)
United Aircraft"3
Westinghouse
General Electric
(for aircraft-type turbines)
Brown Bovari
ERDA*
(*See PON FE-7, Section 4.3)
0.8 pound/10 scf low Btu fuel gas
(or ~12 ppm)
0.03 percent (in fuel oil)
(or 300 ppm by weight)
30 ppm by weight in fuel gas
(10 micron maximum)
1-2 ppm by weight (in gases entering
turbine)
0.75 grains/scf (or-2.6 ppm by weight)
in 0-2P- range
0.001 grains/scf (or~ppb by weight)
in 2-6|JL range
The increased prospective utilization of combined gas/steam turbine/electrical
generating systems, coal gasification and synthetic gaseous fuels has intensified
EPA's interest in HTP particulate removal technology. The economic and operational
incentives for the utilization of HTP particulate removal technology (e.g.,
improved fuel utilization efficiency, combustion of some harmful compounds1, and
the need to handle a smaller volume of gaseous products make HTP particulate
removal appear attractive for EPA.
Specific ERDA projects are described in Section A and EPA projects in Section 5.
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SECTION 2
CONCLUSIONS
1. Fo overlaps.
There does not appear to be any significant overlap or duplication of the
EPA and ERDA programs. The relatively small size of the ERDA program provides
little opportunity for duplication, in itself.
2. Significant gaps exist.
The combined EPA and ERDA effort on particulate control at elevated temperatures
and pressure is not large (Average combined expenditures are less than $2
million per year for contract effort). Gaps or omissions in the combined
activities are most evident in the characterization of particulates and the
study of aerosol mechanics, both of which might be considered to be fundamental
to the development of a strong information base for control technology.
3. Both Agencies have a common interest in solving the overall problem of
particulate control
EPA's role in the control of particulate centers on potential harmful effects
of the emissions while ERDA's orientation is directed at the protection of
equipment employed in advanced energy systems and in increasing system efficiency.
However, each Agency has a substantial stake in the other's main purview of
responsibility. The successful development of advanced energy systems will have
an important bearing on future energy-related emissions. In a similar manner,
the health and ecological effects of these advanced systems must be environ-
mentally acceptable if they are to be implemented. Each Agency has an interest
in the solution of the particulate problems that fall within the primary responsi-
bility of the other.
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If any of these problems remain unsolved, there will be no advanced system
nor will, the expected benefits in health, ecology, or energy self-sufficiency
be realized.
4. Increased interagency coordination is needed.
The interagency interest in the particulate control problem will require
continued coordination in these programs. If the small size of the ERDA
activities can be attributed to their recent inception, it may be expected
to grow in the future. New developments in the field of advanced energy
systems may also stimulate this growth. Increase in the attention given'
to the particulate problem will require a corresponding need for increased
coordination if programs1 are: to be efficiently planned without duplication
and1 without serious omissions and if maximum use is to be made of the
resulting technical data.
5. Equipment protection requirements can be exped.itiously established.
Determination of health and ecological effects may required substantial
lead times due to the need for observations' covering long spans' of life.
Equipment requirements, however,, may be ascertained more expedi'tiously.
Determination of these equipment requirements would set a bottom limit
which would narrow the field of consideration and allow concentration of
effects study resources-^
6.. HTP parti'cu'lat-e cleanup.'not essential for meeting emission standards.
Particulate' cleanup of hot pressurized gases is not an absolute environ-
mental requirement. Removal of offending materials at any point prior to
discharge will satisfy environmental considerations. Early cycle cleanup
12
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may be more efficient because of reduced volume and may allow energy
extraction which would not be practical otherwise. Environmental interest
in the point of cleanup is a function of the efficiency of particulate
removal, along with whatever energy penalties may be avoided. EPA's
interest in the hot pressurized cleanup technology is based upon the
assumptions that advanced energy systems have a good potential for environ-
mental advantages and that these systems will require early cycle cleanup
to avoid unacceptable energy penalties or equipment damage.
7. ERDA does not have centralized programs for particulate control RD&D.
Unlike EPA, ERDA's research and development activities are not organized
around particular pollutants or pollutant control technologies. Consequently,
there is no centralization of responsibilities within ERDA for the control
of particulates at high temperatures. Unless a focal point is established
and functioning at ERDA, program coordination will require contact with a
number of ERDA research and development offices.
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SECTION 3
RECOMMENDATIONS
1. Increase interagency coordination.
Both EPA and ERDA will probably continue to pursue programs in particuTate
control. With growth of developments in advanced energy systems, the s'ize
of this activity may increase from its present level. Efficient planning
of these programs will require close cooperation and coordination.
2. Focus responsibilities for coordination.
Due to the organizational structure of ERDA and the more immediate interest
of EPA -in health and ecological effects, EPA may well be the more logical
organization 'to take the lead and initiative in establishing necessary
channels for coordination.
3. Coordinate1future program plans.
Interagency coordination in particulate control need not be limited to after-
the-fact disclosures of program activities or the exchange of data. Joint
planning of future activities could include discussions and recommendations
for assignments of particular developments. Projects aimed toward filling
identified gaps should receive priority attention.
4. Facilitate technology transfer between agencies.
In addition to the interagency coordination of activities discussed above,
technology transfer should not be neglected. Specific or special provisions
for accomplishing this transfer is appropriate to any coordination discussions
which are held.
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SECTION A
ERDA PROJECTS
ERDA has five specific projects identified as addressing the subject of HTP
particulate characterization, measurement, or control. These are identified in
Table 2 and summarized in the following sub-sections. Specific projects are
described in a consistent format, insofar as possible from available information.
In addition to these five specific projects, it should be noted that there are
many other ERDA programs associated with development of energy systems. These programs
may include requirements for hot gas cleanup incident to operation of experimental
equipment. The program descriptions which follow are those primarily devoted to
particulate control research and development.
4.1 Characterization and Aerosol Mechanics
Of the many ERDA programs devoted to the primary objective of developing advanced
energy systems, several include particulate characterization tasks. While these
programs have other primary objectives, the characterization activity is pertinent
to HTP particulate control. This portion of the applicable programs is briefly
described below.
• At Argonne National Laboratories some studies pertaining to chemical charac-
terization of particulate in the combustion gases generated by a coal fired,
pressurized FBC are being undertaken. This characterization work is done
incident to the evaluation of the effects of operating variables in the bench
scale plant on response variables in the flue gas, including particulates.
Particulates are collected from two series cyclone separators, a sintered
steel filter and a final bag filter.
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TABLE 2. ERDA HIGH TEMPERATURE/PRESSURE PROJECTS
Title
Contractor
Funding
($K)
Milestones
1. Particulate Analysis
Instrumentation
2. Particulate Measurement
in FBC Systems
3. Centrifuge Gas Cleanup
System
4. ESP Development and
Test
5. Moving Bed, Granular-
Bed Filter
Leeds & Korthrup 75
Spectron Development
Laboratories 17
Mechanical Tech-
nology, Inc. 151
Not Awarded
Combustion Power
Company
1/77 Completion
12/76 Completion
5/77 Completion
1/77 Contractor
Selection Expected
12/77 Complete Phase I
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Chemical characterization is oriented toward collecting data relating to study
of additive entrainment under various operating conditions.
• The Exxon Research and Engineering Company is collecting characterization
data in conjunction with its Miniplant (FBC) work. This characterization
work has commenced within the last twelve months and has not yet been compiled
in any of the papers describing Miniplant operation. The data available to
date is limited and reported only in the monthly reports submitted to the
ERDA Fossil Energy Division sponsoring the FBC development.
• Work at the ERDA Morgantown Research Center includes atmospheric FBC develop-
ment. Particular attention is devoted to the combustion of residual mining
wastes not suitable for firing in conventional systems. Various pulverized
coals are also being tested. Chemical characterization data is being developed
in conjunction with the FBC operation. This characterization is not intended
exclusively to determine the character of the process off-gases, as the particle
composition is also indicate of operating conditions such as combustion effi-
ciencies.
• At the ERDA Grand Forks Research Center, data on particle resistivity
is being acquired as a part of ESP operation studies. Particle characteristics
are also being studied within the Fluidized Bed Combustion Wet Scrubber Program.
4.2 Measurement and Instrumentation
Recognizing the potential of measurement devices employing optical properties,
ERDA is currently undertaking two activities in this program area. These projects
are described below.
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PROJECT TITLE: PARTICIPATE ANALYSIS INSTRUMENTATION FOR FLUIDIZED-BED
COMBUSTION SYSTEMS
Contract Number: E(9A9-18)-2412
Contractor: Leeds and Northrup Company
North Wales, Pennsylvania
Total Funding: $106,200
Period of Performance: May 1976 to May 1977
Sponsoring Division: Office of Fossil Energy, ERDA
Project .Officer: Mr. John Geffken
Purpose: To examine the feasibility of monitoring equipment to evaluate
particle characterization in gas streams at high temperatures and pressures.
Objectives:
(1) Adapt an existing measurement technique (low angle forward optical
scattering) to the harsh fluidized bed combustion environment;
(2) Calibrate and test the instrumentation at the Argonne National
Laboratory's pressurized fluidized-bed combustion unit, followed by
demonstration of the unit on the Curtis Wright small gas turbine unit;
and
(3) Evaluate the performance for potential commercial application.
Description of Technology: This instrument utilizes a Leeds and Northrup
low-angle forward scattering technique instrument package for simultaneous
measurement of particle size and velocity. This device will be directly
interfaced with a data sorter (mini-processor) to provide on-line statistical
information, which can be used in a real-time mode or stored for later inter-
pretation.
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The measuring device will be developed to operate at temperatures in
the range 1,500 - 2,000 F, and pressures up to 10 atmospheres. This package
is a potentially useful analytical tool for fluidized-bed combustion research
as an accurate on-line monitoring device for determining the efficiency of
particle filtering systems essential for the commercial deployment of PFBC
systems using gas turbine cycles. In the program, special attention would
be focused on the quality and cleanliness of viewing windows under high
pressure, high temperature, high particle loads, and a highly turbulent
gas stream.
Activities: This project involves the performance of the following six
tasks during the period of performance.
Task 1: Application Analysis and Instrument Optimization
Task 2: Instrument Design and Manuals
Task 3: Fabrication and Assembly
Task 4: Check Out and Test
Task 5: Installation and Training Support
Task 6: Data Evaluation
PROJECT TITLE: PARTICLE MEASUREMENT IN FLUIDIZED-BED COMBUSTION SYSTEMS
Contract Number: E(49-18)-2413
Contractor: Spectron Development Laboratories, Inc.,
Costa Mesa, Calif.
Total Funding: $17,219
Period of Performance: April 1976 - December 1976
Sponsoring Division: Office of Fossil Energy, ERDA
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Project Officer: Mr. John Geffken
Purpose: To examine the feasibility of an advanced diagnostic technique to make
particle field measurements in fluidized bed combustion systems.
Objectives:
(1) Test the capability of a Spectron Development Laboratories Particle Morphokine-
tometer (PM) to obtain particle size and velocity measurements in the output
train of a FBC at Argonne National Laboratories;
(2) Determine operational limitations in terms of particle loading in the flow,
light scattering outside the sample volume, and environmental limitations
including window contamination, window flange creep, and window deformation
due to high temperature and pressure; and
(3) Analyze acquired data by comparing particle size distribution and mass
estimates with other available sampling techniques, and .estimated instrument
sensitivity to variations in particle content.
Description of Technology; The particle morphokinetometer involves the
mixing of two equally intense coherent light beams at an angle. The inter-
4 • •
ference of the two beams produces a set of well defined equally spaced
interference fringes. The light scattered by a particle traversing the
fringe set is modulated according to the size and position of the particle.
The particle size is determined by the ratio of the amplitudes of the
modulated scattered intensity to the average scattered intensity. The
signal time period is a measure of the particle velocity.
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Activities: This project has the following milestones:
- design and installation of windows and flanges on the output train
of a FBC at Argonne National Lab (ANL) (completed in October 1976)
- instrument operation for both cold and hot FBC flows for four weeks
at ANL by SDL and ANL personnel (completed November 1976)
- report summarizing data and instrument evaluation by ANL and SDL
personnel (due December 1976)
4.3 Control Technology
The major projects in ERDA's high temperature/high pressure particulate
control technology effort are described below:
PROJECT TITLE: STUDY OF CENTRIFUGE GAS CLEAN-UP AND SEPARATION SYSTEM
Contract Number: E(49-18)-2428
Contractor: Mechanical Technology, Inc.
Latham, New York
Total' Funding $151,000
Period of Performance: May 1976 to May 1977
Sponsoring Division; Materials & Power Generation, ERDA
Project Officer: Mr. W. Fedarko
Purpose: To examine the feasibility of centrifuge systems for gas particu-
late clean-up and gas constituent separation in coal conversion processes,
with special emphasis on HTP operation of centrifuges.
Objectives:
(1) Determine the effectiveness and process economic advantages of centrifuges
(alone or in combination with cyclones) for removal of particulates from
the gas stream generated by coal combustion or coal conversion processes.
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(2) To evaluate the effectiveness and process economics of the centrifuges
for separation of gas constituents is also an objective of this project.
(3) To study the technical performances of centrifuges as a function of
various operating conditions (flow rates, degree of purity, pressure,
temperature, etc.) up to pressures of 1,000 psig, temperatures of
1500 F, and flow rates as high as 200,000 scfm.
Description of Technology; In this process, centrifuges will be utilized
for separating particulate from the low-Btu gas stream produced by a
gasifier. In equipment to be tested, a centrifuge is combined with
a cyclone for separating fluids of different specific gravities or for
separating suspended particles from a gas stream, by utilizing the centri-
fugal force generated by the rotary motion.
The substitution of centrifuges for other methods of removing particu- .
late from high- and low-Btu gases should result in better separation factors,
thereby producing fuels of higher purity at lower costs. Centrifuges are
more compact and require less energy than present particulate removal
facilities. If the upper temperature and pressure limits and particulate
removal efficiencies are acceptable for the process clean-up, the centri-
fuge systems could offer an effective and economical alternative for HTP
particulate clean-up.
Activities: In this project the following activities and time schedules
are planned:
(1) Determine centrifuge capabilities in terms of flow rates, clean-up
efficiency and reliability at high temperatures and pressures (to be
completed in early 1977).
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(2) Scudy the process economics, including the initial and operating costs,
involved in employing centrifuges for particulate removal and separation of
gases at HTP (to be completed by (May 1977).
(3) Study the effect of centrifuge size, velocity, diameter, length,
casing design, materials, method of suspension, drive, controls, and
number of stages (series and parallel) on the technical performance
and economy of centrifuge systems (to be complete in May 1977).
(4) Prepare optimized conceptual designs of appropriate centrifuge systems,
giving engineering details, expected performance, power requirements
and estimated costs (to be completed by May 23, 1977).
PROJECT TITLE: GRANULAR BED FILTER DEVELOPMENT
Contract Number: EF-77-C-01-2579
Contractor: Combustion Power Company
Total Funding: $928,306
Period of Performance: January 1977 - December 1977
Sponsoring Division: Office of Fossil Energy, ERDA
Project Officer: Mr. John Geffken
Purpose: The purpose of the first phase of this contract is to determine the
scientific and engineering principles upon which granular bed filteration
operates. In particular, the granular bed filtration process will be analyzed
theoretically and evaluated.
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Objectives:
(1) To determine the scientific and engineering principles upon which granular
bed filtration operates.
(2) To predict the effects and inter-relationships of Granular Bed Filter (GBF)
design var-iables.
(3) To predict the filtration performances of the GBF from a given set of design
variables.
Description of Technology: Combustion Power Company, Inc., was awarded a contract
to perform an intensive program to determine the scientific and engineering
principles upon which granular bed filtration operates. The first phase of the
program will develop the theoretical analysis of the moving bed granular bed
filtration process and perform verification testing at ambient temperature.
Specifically, work will be performed on cold testing and mathematical modeling.
The cold flow facility will be designed with the provision for subsequent hot
flow testing. If successful, the program will continue with & series of hot
mode tests, and construction and operation of a process development unit scale
MB-GBF to show its commercial applicability. Subsequent phase (e.g. hot flow
tests) will be scheduled to insure that the GBF program continues on a timely
basis. Hot gas cleanup is necessary for commercial application of pressurized
•fluidized bed combustion, GBF is one of the most viable contending systems.
Application -is also seen in coal conversion plants.
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Activities: This project involves the performance of the following seven tasks
during the period of performance.
Task 1.1 Theoretical Analysis of Granular Bed Filtration Process
Task 1.2 Calibration of Particle Sampling Equipment
Task 1.3 Dust Loading and Sampling Calibration Test Set-Up
Task 1.4 Cold-Flow Model Design
Task 1.5 Cold-Flow Model Test Set-Up
Task 1.6 Cold-Flow Model Tests for Design Variables
Task 2 Front Face Cleaning
PROJECT TITLE: ELECTROSTATIC PRECIPITATORS DEVELOPMENT AND TEST OPERATIONS
DEMONSTRATIONS (PROGRAM OPPORTUNITY NOTICE)
Contract Number: PON FE-7
Contractor: Not yet selected
Total Funding: Undetermined
Period of Performance: Contractor selection expected by January 1977.
No other details available at this time.
Sponsoring Division: MERC (ERDA)
Project Officers: Mr. Charles Grua, Mr. Corell Shale
Purpose: To develop and demonstrate by test operations, electrostatic
precipitators for particulate removal from gaseous fuels produced from
coals at temperatures in the range 1000 F to 1800 F and at pressures
ranging from one atmosphere to 450 psl.
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Objectives:
(1) To demonstrate by test operations an improved electrostatic precipitator
capable of high temperature operation with acceptable collection efficiency.
(2) To enhance the utilization of low-Btu gas as a substitute for natural
gas by extending the state-of-the-art of purification methods., and
to improve the efficiency of gas turbine or combined cycle power ^plants
through the removal of particulates from low-Btu gas at high temperatures
and pressures.
(3) To demonstrate that improved ESPs can attain particulate removal effi-
ciencies of 99.5 percent to 99.9 percent, and clean low-Btu gas such
that it contains less than 0.75 gr/scf of particulate in 0-2 micron
range, and less than 0.001 gr/scf in the 2-5 micron range.
Description of Technology: The particulate loading specification for gas
turbines require a high removal efficiency for particulate in the size range
of 2p and larger. . Electrostatic precipitators which operate very effectively
at moderate temperatures and pressures can be expected to be utilized success-
fully at high temperatures and pressures provided the desirable properties
of the .collection equipment and particulate can be maintained under these
severe conditions. The ESPs have a low pressure drop, high efficiency for
small particulate, and possess the ability to handle both gases and vapors
for high volume flow. The collected particulate can be removed easily..
The steps in the electrostatic precipitation of particulate are:
- place a charge on the particle to be collected
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- attract the particle to the collector which has opposite charge,
- neutralize the charge at the collector and remove the collected particle.
At high temperatures, the particle resistivity may be low enough to
cause excessive reentrainment. Also, the particulate may generate thermionic
emissions, thereby diminishing the charge on the particles, and a resultant
drop in collection efficiency may occur. The material used for electrodes may
not be able to withstand the severe conditions...This may result in misalign-
ment of electrodes, non-uniform charging, and failure of the electrode material.
If the problems listed above can be tested through the use of superior
design, improved material, and better operation procedure, ESPs may turn
out to be as effective at high temperatures and pressures as they are at
moderate levels of temperatures and pressure.
Activities: This program will include the following activities (milestones
not, yet scheduled):
(1) One or more improved versions of electrostatic precipitators will be
tested in conjunction with a coal gasifier.
(2) The precipitator design and characteristics will be improved until
it is capable of displaying adequate particulate.removal efficiency
at high temperatures (up to 1800 F) and high pressures (up to 450 psi).
(3) The demonstration of the capabilities of an improved ESP 'for HTP
particulate removal will be carried out in conjunction with a gasifier.
This gasifier may either be owned by the contractor or be provided
by the Morgantown Energy Research Center of ERDA.
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PROJECT'TITLE: WESTINGHOUSE SHOCK TUBE (INACTIVE)
The project described -below is not currently active and consequently
not properly considered as a part of the ERDA program. Mention is made
•here as a matter of convenience in the belief that it will be.of interest to
.the reader. The work completed, and that which may be initiated in the future,
could provide a significant contribution in establishing particulate require-
ments for turbine operation.
The :project, recently completed by Westinghouse, was sponsored by the
ERDA Division of iFossil Energy under contract E(49-18)-1514. The work was
associated with Advanced Coal Gasification for Electric Power Generation
conducted July, .1975 through June, 1976. This low^Btu gasification project
was done in conjunction with the Public Service Company of Indiana.
The Westinghouse'particulate study objective was to define the parti-
culate tolerance of turbine blades necessary for development of equipment
to be used in the low-Btu gasification process.
Determination of particulate .tolerance is accomplished in an erosion
prediction 'process using-a combination of mathematical models and experi-
mental data. A unique feature of the -technique concerns the use of a shock
tube to produce .experimental data for the erosion and deposition-models..
The 'Shock 'tube provides for acceleration of measured amounts of 'particulate
along with IDop.p'ler laser measurement at the point of impingement on the
test blades, adjustable to various impact angles.
The shock tube ^experimentation was restricted to low temperature gas
streams. However, the operators believe that heating the shock tube may
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be controlled to produce an aerosol suitable for examination of gas streams
in the 2000 F range. While proprietary development is reported as continuing,
the technique remains a possible condidate for future joint development.
4.4 General Comments on ERDA Programs in the HTP Particulate Removal
ERDA's work in the area of HTP particulate control is oriented primarily
toward prevention of the damage that might be caused to the turbine by the parti-
culate which are allowed to enter the turbine. Consequently, the measurement
techniques and particulate removal mechanism being developed, tested, and demon-
strated by ERDA are designed to address the particulate fraction which falls in
the 2p and larger size category, although it is recognized that the lower end
of the size range of particles that might damage turbine equipment is not yet
firmly established. While it is entirely possible that some pollutants in the
vapor form might also cause damage to the turbine, the current efforts are
directed mainly at particulate control as a means for minimizing the erosion,
corrosion and deposition problems in gas turbines.
The ERDA program does not currently include a substantial effort for charac-
terization of particulate matter found in the gas streams entering the gas turbine,
in terms of its chemical and physical properties. However, an increase in character-
ization work is planned on completion of construction of those pilot plants which will
produce hot gas streams. This characterization will be done as part of the operational
experimentation.
In the area of measurement instrumentation, ERDA has two projects in progress.
These activities are aimed at the development, testing, and demonstration of
measuring devices using optical scattering techniques for in-situ installation.
Coupled with on-line data processors, these devices are capable of yielding
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simultaneous measurements of particle size distribution, concentration and
velocity. In terms of operating ranges, these devices cover temperatures up
to 2000 F and pressures up to 10 atmosphere. The temperature parameter is
adequate for most anticipated uses, but the pressure range may be inadequate,
because ERDA is about to start testing and demonstrating particulate control
equipment at pressures as high as 1,000 psig. Therefore, it would be desirable
to extend the pressure limit on the operation of these measuring devices.
ERDA is currently engaged in testing and demonstrating the capabilities
of centrifuges and ESPs for particulate removal at high temperatures and
pressures. In the absence of well-accepted specifications for allowable parti-
culate loading and size distribution for gas turbines, it is difficult to select
the most effective techniques for particulate removal at high temperatures and
pressures. A knowledge of these specifications will also give some indication
concerning the impact of turbine exhaust gases on the ambient air (in terms of
particulate concentration).
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SECTION 5
EPA PROJECTS
EPA currently has eight active projects that address the control of particu-
late matter at HTP conditions. These are identified in Table 3 and are summarized
in the following subsections. It is noted that seven of the eight ongoing projects
are components of EPA's Particulate Control Program; the other is part of the
Fluidized Bed Combustion Program and is identified as such.
5.1 Characterization and Aerosol Mechanics
In the past, EPA's major interest in the characteristics of particulate
matter has centered on the effects of such material on the environment and human
health. Emphasis has consequently been placed on the characteristics of particles
in ambient air. One study on the mechanics of aerosols at high temperature and
pressure was recently completed (August 1976) (Reference 2). At present, EPA has
no active projects on particulate characterization at HTP conditions.
5.2 Measurement and Instrumentation
EPA funded one project on measuring particulate parameters at HTP conditions
during FY 1976. The original specifications of this project were as follows:
r
PROJECT TITLE; MEASUREMENT FOR HIGH TEMPERATURE/HIGH PRESSURE PROCESSES
Contractor: Acurex/Aerotherm Division
Total Funding: $ 90,000 (FY 76)
$120,000 (FY 77)
$ 70,000 (FY 78)
$ 25,000 (FY 79)
$ 25,000 (FY 80)
Period of Performance: October 1975 to October 1978
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TABLE 3. EPA HIGH TEMPERATURE/PRESSURE PROJECTS
OJ
N3
Title
1. HTP Measurement
2. Hot ESP
3. HTP Filtration
4. Ceramic Filter
Materials
5. New Concept for HTP
Collection (Dry Scrubber)
6. Assessment of Granular Bed
Filter Technology
7. Granular Bed Filter
8. Collection Mechanisms
(Aerosol Mechanics)
Contractor
Aerotherm
Acurex
Cottrell
Environmental
Sciences
Aerotherm
Acurex
Westinghouse
Air Pollution
Technology
Air Pollution
Technology
Exxon
Research
Air Pollution
Technology
Funding ($K)
90 ;(FY-76)
120 '(FY-7?)
70 (FY-78)
25 '(FY-79)
25 (FY-80)
137 XFY-75)
284 (FY-76)
593 (FY-76)
240 (FY-75)
431 (FY-76)
140 (FY-76)
150 (FY-76)
300 (FY-77)
50 (FY-75)
300 (FY-76)
10/75
9/78
4/76
1/77
1/78
4/79
8/76
9/77
3/76
7/77
10/78
8/76
9/77
8/76
9/77
7/77
7/78
Phase
1/77
Phase
2/78
Milestones
Measure/Develop
Final Report
Define Stable T&P
Demonstrate Feasibility
Complete Pilot Scale
Complete Demo
Primary Evaluation
Verification
Demonstrate Feasibility
Complete Pilot test
Complete Demo
Primary Evaluation
Verification
Primary Evaluation
Verification
Complete System Study
Complete Demo
1 - Completed
Final Report
2 - Underway
Final Report
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Sponsoring Division: Particulate Technology Branch, IERL-RTP, EPA
Project Officer: Mr. William R. Kuykendal
Purpose: This project is being conducted for the purpose of evaluation,
development, field testing and application research of high temperature,
high pressure measurement techniques necessary for HTP particulate control
technology development.
Objective: The first technical objective of this project is to develop
measurement instrumentation needed for measuring the mass loading, size
distribution and velocity of particulate in gas streams at high temperatures
and pressures.
The second objective is to develop measurement support for the evaluation
of particulate control technology being developed by IERL.
Description of Technology: The technical approach being followed in this
project is similar to that adopted for the Method 5 particulate train. This
train consists of a water jacketed probe which collects the sample and directs
it into a cyclone. The cyclone is followed by an impactor, a filter, and an
impinger (for condensible products). The outlet from the impinger is con-
nected to a pump which delivers the dried sample to a dry gas meter.
In the first phase, technology development will concentrate on the
testing and demonstration of a short-term measurement system for particulate
and gaseous concentration. The second phase will involve a three year
effort aimed at the development of an optimized measurement system for
particulate at HTP.
Activities: The activities in the two phases of this program are described
below.
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Phase I
Develop an acceptable measurement system 'for the measurement of pa-r-ticifiate-
and gaseous concentration/composition data at high temperatures and pres-
sures (due for completion in October 1976).
Phase II
Develop an optimized system for the measurement of particulate and gaseous
concentration/composition data at high temperatures and pressures (due 'for
completion :by October 1978).
5.3 Control Technology
In fulfilling its responsibility to develop and demonstrate ;particulate
control technology, EPA is currently conducting the following projects 'that
address the control of particulate matter in HTP gas streams'.
PROJECT TITLE: DEVELOP HIGH TEMPERATURE AND PRESSURE ELECTROSTATIC
PRECIPITATOR .(ESP) '
Contractor: .Research Cottrell
Total -Funding: $137.,000 (FY 1975)
$284 ,.000 (FY 1976)
Period of Performance: April 1976 .to April 1979
Sponsoring Division; Particulate Technology Branch, lERL-RTP,, EPA
Project Officer: Mr. Leslie E. Sparks
Purpose: The purpose of this project is to determine the suitability of
electrostatic precipitators for particulate cleanup at high temperatures
and .pressures.
Objectives: There are two phases of this project, with the following.
objectives:
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Phase I
(1) To define the temperature-pressure regions in which stable electro-
static precipitator operation is possible.
(2) To determine the temperature/pressure conditions in advanced energy
processes, both for synthetic fuels and combustors.
Phase II
If there is sufficient overlap between the system (advanced energy pro-
cesses, synthetic fuels) requirements and ESP operating conditions, the
objective of this phase will be to develop high temperature/pressure ESP's.
Description of Technology: EPA's major interest is focused on fine particu-
late removal, and there have been some doubts about the effectiveness of
ESP's in removing fine particles from the gas stream. In the case of these
small particles, the main particle charging mechanism, "field charging"
makes up for the lack of diffusion charging in the case of particles which
are smaller than 1/2 micron. Under moderate operating conditions (pressure
and temperature), the ESP's display minimum collection efficiency for
particles in the size range 0.1 to 1.0 microns.
Activities: The activities involved in this project include the following:
(1) Determine corona characteristics at temperature up to 2000 F, and
pressures up to 500 psi in combustion gas and fuel gas environment.
In particular, determine the impact of high temperature on particle
resistivity, thermal ionization, re-entrainment and critical pressure.
(2) Identify the temperature/pressure limits for stable ESP operation, by
conducting batch operation of a single tube pilot precipitator.
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(3) Develop and operate a multiple prototype module in continuous operation
mode.
PROJECT TITLE; THE DEVELOPMENT OF HIGH TEMPERATURE. HIGH PRESSURE^PARTICLE
CONTROL BY FILTRATION
Contractor; Acurex Corporation/Aerotherm Division
Total Funding: $593,000
Period of Performance: August 1976 to August 1978
Sponsoring Division; Particulate Technology Branch, IERL-RTP, EPA
Project Officer: Dr. D. C. Drehmel
Purpose: The purpose 'of this project is to support the development of
filtration as a technique for removing particulate from the high temperature/
pressure gas stream generated by gasifiers and combustion (pressurized FBC).
Objectives: The following are the major objectives of this project.
(1) To develop filtration procedures for ensuring that tihe gas turbines
using ;gases generated by gasifiers and pressurized FBCs are protected
from 'the suspended particles in these fuel gases.
(2) To determine the •suitability of the filtration concept as an effective
means for controlling suspended particulate at high temperatures and
pressures.
(3) To develop a'pilot scale HTP filtration device.
(4) To carry-out an economic analysis of full scale filtration systems.
Description' of 'Technology; Filtration is one of the most reliable techniques
for removing 'suspended particles from gaseous streams. However, the severe
conditions represented by high temperatures and pressures require care'ful
36
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consideration in the selection of materials and designs for filters to be
used in this environment.
The most promising candidates for filter material are ceramics (silica,
alumina, zirconia, etc.). which can be woven or felted into a gas filter.
Abrasion in weaves can be reduced by high temperature coatings and novel
weaving techniques.
Activities: This project will be conducted in two phases. The activities
in each phase are listed below.
Phase I - Preliminary Evaluation
(1) Carry out theoretical studies concerning filter operations under high
temperature and pressure conditions.
(2) Select and obtain test materials for filters; design, fabricate and
construct test apparatus.
(3) Conduct experiments and collect data.
(4) Analyze data and carry out an economic analysis of filtration as a
means for HTP particulate control.
(5) Conduct bench scale testing of the selected filtration system.
Phase II - Verification
(1) Plan experiments for verifying the results yielded by Phase I.
(2) Conduct experiments, collect data, analyze data and generate results
pertaining to the validity of the indications yielded by the preliminary
evaluation.
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PROJECT TITLE; DEVELOP CERAMIC FILTER
Contractor: Westinghouse
Total Funding: $240,000 (FY 1975)
Period of Performance; March 1976 to October 1976
Sponsoring Division; Particle Technology Branch, IERL-RTP, EPA
Project Officer: Dr. D. C. Drehmel
Purpose: To determine the suitability of ceramic filters as a means for
removing particles from combustion and fuel gases for the purpose of pro-
tecting gas turbines and the environment.
Objective; The overall objective of this project is to develop and demon-
strate ceramic filters for removal of particulate matter from gas streams
at high temperatures and pressures.
In the first .phase of this project, the objective is to demonstrate
the feasibility of using such filters under severe conditions represented
by high temperatures (up to 2000 F) and pressures (up to an undetermined
level).
Description of .Technology; Cyclones (or centrifuge), scrubbers, ESPs and
fabric filters are the four particulate removal techniques in use at this
time. Various design, material and .operational problems have resulted in
the first three techniques being relatively less successful in cleaning
HTP gases. Fabric ,and bed filters have consistently shown acceptable levels
of performancejeven under extreme conditions. Because,.of the [Severe opera-
ting environment, the selection of .a durable material for filters has been
a prime objective of researchers dealing the HTP control technology.
38
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Westinghouse has tested a ceramic filter developed by Horizons Inc.
The results have been satisfactory, in terms of collection efficiency,
operating reliability, and durability of the equipment. Contrary to
original expectations, the pressure drop in the ceramic filter was not
very high. Initial indications are that it would be feasible to use
ceramic filters for removing particulate from gases at high temperatures
and pressures.
Activities:
(1) Demonstrate the feasibility of using ceramic filters for particle
removal from gaseous streams at high temperatures and pressures
(already completed).
(2) Completed pilot tests involving the use of ceramic filters for
removing particles from HTP gases (due March 1977).
(3) Conduct a demonstration of a particulate clean-up system using ceramic
' filters (due for completion in October 1978).
PROJECT TITLE; NEW CONCEPT FOR HTP COLLECTION (DRY SCRUBBER)
Contractor: Air Pollution Technology (APT) Inc.
Total Funding: $431,000
Period of Performance: August 1976 to August 1978
Sponsoring Division: Particulate Technology Branch, IERL-RTP, EPA
Project Officer: Dr. D. C. Drehmel
Purpose: To develop an innovative technique for controlling fine particulate
at high 'temperature and pressure.
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Objective:
(1) To conduct theoretical and experimental studies aimed at the development
of a new concept for fine particulate control at high temperature and
pressure.
Description of the Technology; The technology to be examined is a "dry
scrubbing system" for controlling fine particulate matter in a gas stream.
The system provides for contacting the fine particle-laden gas to be cleaned,
with large (diameter of 100^ or more) collector particles. The collectors
(large particles) are introduced in a contactor unit consisting of a venturi
like device allowing injection of the collectors in the venturi throat. Agglo-
meration of the fine and large particles will allow removal in a subsequent
separator designed for high efficiency removal of large particles. A gravity
settler and virtual impactor are to be evaluated for the separation step. The
system will be examined at the bench and pilot scales. Regeneration and recycle
of the collector particles is planned as part of the system but is to be
evaluated independently of the bench and pilot demonstrations. These demon-
strations will be operated at high temperature and low pressure in the expec-
tation that the impaction mechanism is not specifically dependent on pressure.
Collector particles to be used will include ash particles, large agglomerates
of fine particles, and metal beads.
Activities
The technical objectives of the project will be completed in two phases:
40
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Phase I: Preliminary Evaluation of the Dry Scrubbing Concept
1. Theoretical calculations of the mechanism of fine particle collection through
use of relatively large particles (8/76 - 11/76);
2. Bench scale experiments to evaluate the concept (8/76 - 3/77);
3. Economic analysis based upon the theoretical calculations and bench
scale experiments (2/77 - 4/77);
4. Investigation of the energy and cost relationship as a function of temperature
and pressure (3/77 - 5/77);
Phase II: Verification of Fine Particle Collection
1. Formulation of a verification test plan (5/77 - 8/77);
2. Design of a 500 SCFM Model (6/77 - 12/77);
3. Test of the 500 SCFM Model (12/77 - 6/77); and
4. Economic analysis of dry scrubber operation based on data obtained in test
of the Model (6/77 - 8/77).
PROJECT TITLE: ASSESSMENT OF GRANULAR BED FILTER TECHNOLOGY
Contractor: Air Pollution Technology (APT) Inc.
Total Funding: $140,000
Period of Performance: September 1976 to June 1978
Sponsoring Division: Particulate Technology Branch, IERL-RTP, EPA
Project Officer: Dr. D. C. Drehmel
Purpose: To evaluate the existing granular bed filter systems for assessing
the suitability of this technology for particulate control at high tempera-
ture and pressure.
41
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Objective: The objectives of this project are:
(1) To evaluate the status of the current granular bed filter technology...
(2) To assess the adequacy of granular bed filters for meeting the parti-
culate clean-up requirements of various advanced energy systems.
Description of Technology: In order to maintain high thermal efficiency
and protect the turbines in advanced power systems, it is necessary to
remove the particulate from the gaseous fuel stream at high temperatures
and pressures. Along with ESPs, fabric filters, and centrifuges, granular
bed filters offer the potential of effective and reliable service under these
conditions.
Under other EPA projects, there is performance data concerning existing
granular bed filters (including the Rexnord filter)• These data indicate
relatively poor performance in removing fine particles (1M- in size). The
Combustion Power Company (CPC) granular bed filter not available for test
at this time.
The assessment of the performance of various existing granular bed
filter systems will lead to the development of engineering models and
design equations for predicting filter performance. These systems will be
designed for operations at pressures up to 15 atmospheres and temperatures
up to 1100 C.
Activities; This project is being conducted in two phases. The following
activities are scheduled:
Phase I
Study the literature pertaining to empirical and theoretical information
concerning granular bed filters. (Due to be completed by September 1977).
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Phase II
Carry out field sampling, and conduct detailed costs at two granular bed
filter installations selected as a result of Phase I study. Determine the
effectiveness and characteristics of these two systems. Prepare a final
report by June 1978.
PROJECT TITLE: PARTICULATE CONTROL IN PRESSURIZED FBC-GRANULAR BED FILTER
APPLICATIONS
Contractor: Exxon Research and Engineering Company
Total Funding: $150,000 (FY 76)
$300,000 (FY 77)
Period of Performance: December 1976 to December 1978
Sponsoring Division: IERL, RTF, EPA
Project Officer: D. B. Henschel
Purpose: To design, develop and demonstrate a granular bed filter for
particulate clean-up of combustion gases produced by a pressurized,
fluidized coal combustion bed.
Objectives: The major objectives of this project are:
(1) To establish operational feasibility of granular bed filters under
pressurized FBC operating conditions.
(2) To optimize the performance, and measure the long-term effects asso-
ciated with an expandable sand type granular bed filters.
(3) To demonstrate the ability of granular bed filters to meet EPA
emissions standards by cleaning fuel and combustion gases at high
temperatures and pressures.
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Description of Technology: In a pressurized FBC, the combustion gases are at
pressures up to 10 atmospheres and temperatures up to 1600 F. The particulate
in the combustion gases must be removed before the gases go into a gas tur-
bine. The system being developed by Exxon involves two stages of cyclones
followed by a Ducon granular bed filter between the FBC and the gas turbine
inlet. Particles retained by the granular bed filter are periodically
removed by "blowing back" with compressed air.
Activities:
(1) The installation of a Ducon bed filter is scheduled for completion by
December 1976.
(2) The filter will be checked out during the period December 1976 to
May 1977.
(3) The filter operation will be carried out over a 15 month period
(May 1977 to August 1978). During this time period, efforts will be
made to measure the performance of the Ducon granular bed filter and
optimize its particulate removal efficiency. Maintenance of high removal;
efficiency over an extended period of time will be an objective during this
period. The extension of equipment life will also be a target.
(4) Starting in March 1977, an alternate HTP particulate removal system will
be selected, designed and installed. The checking out and operation
of this device will be completed by December 1978.
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PROJECT TITLE: EFFECTS OF HTP ON PARTICLE COLLECTION MECHANISMS
Contractor: Air Pollution Technology (APT) Inc.
Total Funding: $350,000
Period of Performance: December 1975 to November 1977
Sponsoring Division: Particulate Technology Branch, IERL-RTP, EPA
Project Officer: Dr. D. C. Drehmel
Purpose: To conduct theoretical studies of aerosol mechanics at HTP
followed by laboratory experimentation.
Objectives: The objectives of this project are followed in two phases:
Phase 1
To determine the effects of temperature, pressure and particle diameter of
aerosols on various particle collection mechanisms, and to identify useful
collection mechanisms through theoretical studies.
Phase 2
To conduct laboratory scale experimentation to fill the gaps and reduce
the uncertainties identified in the theoretical study results produced in
Phase 1.
Description of Technology; This project does not concern a particular or
specific technology in the sense that would apply to development of instru-
mentation or a collection or removal device.
The project is intended to develop analytical techniques for studying
the high temperature and pressure aerosol mechanics which will in turn pro-
vide the data necessary for development of particulate control technologies.
These gas mechanics are imperfectly understood with the uncertainties
45
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representing a significant gap in the capability to develop associated1
measurement and control devices.
Activities:
(1) Phase 1 has been completed'with a Final Report scheduled in January'b/f:-(i9'7,7!.
(2) Phase 2 is underway with completion scheduled for November o'f I977 and; a'
Final Report in February of 1978.
5.4 General Comments' on EPA Programs in the HTP Particulate Control Area
Although EFA's interest in HTP particulate control is related only indirectly
to the development of .advanced energy systems using gasification or fluid'ized bed's,
the Agency has a strong interest in the development of HTP particulate control
technology because of the potential environmental impact of the emi'ssiciris from ga's-
turbines and other energy conversion equipment. EPA's major concern is to ensures
that adequate control systems are available at the time needed for applicatiioVi to-
new energy conversion technology.
EPA considers it highly desirable to have specifications for allowable
particle concentration and- size distribution- for gas turbines. Such' specifica-
tions would make it possible for EPA'1 and ERDA to determine the extent of commona-
lity that exists between ttieir respective requirements for HTP particulate control
systems. For instance,, the requirements for gas cleanliness for turbine- pro"t-ec-
tion are believed to depend on turbine design' arid may be less: stringent than"1 for'
environmental protection. Even if the turbine specifications for total particul'ate
loading are more stringent than that for environmental protection, the emissions':
46
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from turbines may include a high proportion of small particles (<2p) and the environ-
mental impact of these emissions may be disproportionately serious (relative to
total emissions).
An attractive feature of high temperature/high pressure particulate cleanup
is the smaller volume of exhaust gases prior to combustion. However, the severe
environment at the turbine inlet may result in low collection efficiency and
equipment reliability. Therefore, a detailed cost benefit study should be performed
to evaluate the economics of HTP particulate clean-up as compared with particulate
removal under moderate conditions.
EPA's current efforts in the area of HTP particulate control technology
development are principally concerned with filters, electrostatic precipitators,
and granular beds. Cyclones and centrifuges are not being addressed by any of EPA's
ongoing projects.
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SECTION 6
COMPARISON OF ERDA AND EPA PROGRAMS
The preceding sections describing the Agencies' high temperature and pressure
particulate control activities are organized into the categories: of:
- Characterization and Aerosol Mechanics,
Measurement and Instrumentation, and
- Control Technology
This same organization is employed in this1 comparison which is directed1 toward!
identification of any overlaps or duplication among the projects1 and discussion'.
of the gaps or omissions. As will be noted, little if any overlap is1 detected,
while a comprehensive program coverage is yet to be achieved.
6.1 Characterization and Aerosol Mechanics
6.1.1 Overlaps
While EPA has recently completed one study of HTP aerosol mechanics and1 has
another currently under way,, neither Agency is; currently pursuing programs' for'
characterizing particulate matter in terms of chemical composition or size distri-
bution. ERDA's work in this area is confined to whatever is- done incident to1,,
or as a part of, development work in advanced energy processes. Thfsr report is
not inclusive of all such ancillary work which may have- produced characterization
data, or will in the future.. In the absence of specific characterization programs,
there is no evidence of overlaps except as! may or may not occur casually in the
advanced energy systems- research, development, and demonstration.
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6.1.2 Gaps
Since EPA has a single current project on aerosol mechanics, and neither
EPA nor ERDA have current characterization projects, gaps in this area include
all necessary characterization and study of aerosol mechanics which has
not been completed. Without attempting to enumerate all the potential gaps,
I
characterization of the hot gas streams from all promising gasification and
pressurized fluid bed combustion processes would seem to be likely candidates.
This would include data on physical and chemical characteristics of particu-
late matter and on aerosol mechanics up to 2000 F and 1000 psig; and for the
various fuels used by the advanced energy processes.
6.2 Measurement and Instrumentation
6.2.1 Overlaps
The EPA program does not include instrumentation test or evaluation which is
in any way similar to the two ERDA sponsored devices under investigation. There
is no evidence of overlap or duplication.
6.2.1 Gaps
The collective instrumentation programs of EPA and ERDA includes only the
three devices described. It seems probable that there are many more devices and
measurement techniques worthy of evaluation. More specifically, two of the three
devices mentioned are designed for pressures up to ten atmospheres. The need for
measurement of hot gas streams to 1000 psig will be required.
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6.3 Contrpl; Technolog-ies.;
6;. 3; li Over-laps-,
B,ot-h-. EPA\ and; ERDA; have; psriOj;ec.tss fore the; development- of"" hot: ESE"s'.. Noi ot-Ker,:
areas..,of. pptent-ial: duplication-, haye; been--, identiff±ed;!..
Two.-, separate, programs in the:-dieyelopmenb off electrostatic: precipitator.s?
do not necessarilyv constitute, an- overlaps even- ifi the; devices^ are.' ihtendedi toi
operatef.on :.s-imi-larr hp.tt. gas;; str.eams.i, proyid.edj the;, pr.ecipitator,: mechanics^ or.'
technologyvdif f err significantly.. The. ERDA1^ program- is- in> the; procurement, stage,,
not - underr contract", ( and-j inf prmatlpn- regarding- detaiis--! off operation" iss not*:
ayailable,.. Cpnsequ,ently-j t whateyerj duplication -may exists between-- the?, two > pro?-
grams.,cannotrbe,»assessed^ at; thlsc
6i3.2;;
SeyenfOf f;thesprograms5jrepprted..-;h'ereiri-imay;'be« included; in-, the?general! cate=-
gory. of; control j.technolpgy|:deyelppment';, Th'e^ technologies?; inc'ludecelec-trostatlc"
pr.ecipitatprs, _t granularrbed.jfilters5. ceramicf-materia-lsr,. aadry;.- scrubber- andr; a^
centrifuge... Gapsyin.nthisadeyelppmenti:and-ievaluation : includesthoseftpossible-;-
devices,jnptfbeing-cpnsidered.^anddthe,-:limitinggcharacteristicsMof; the^hbtigas'1
streamsiS;tp^wh.ich?vthef-.deyices2mighttbeaappliedri. Penddrig?.;the<':suecesssaeh;Leved:i'*inr.
the. deyelppment; which ^issunderwayv. it fdoes.::nott appear ^ obvious;; that ^ any v specif icf.
areas ?ar,eebeingoneglected«attthisstime; . Theeeff6rt-and;-;attention;;beinggaccorded;s
the jprpblems <-p|5cpntrpl [technplpgy-/probablyyexceedsstheplevel I of f additipnal),wor-kt'
needed in.cha;racter4-zatipn,i ^nstrument-ation}- .andcinj.'establishinggtheerequirements'*
fpr protect ion-of.; human ;.health,. ,the,--ecology-, ,^and 'equipment: which!:wi'll,';reeeiv.e*the--
hot gas .streams .-
50
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REFERENCES AND BIBLIOGRAPHY
1. Dhillon, H. and H. Mahar. Alternate Control Strategies for Fine Particles.
The MITRE Corporation, METREK Division, (M76-76), August 1976.
2. Rao, A. K., M. P. Schrag, and L. j. Shannon. Particulate Removal From Gas
Streams at High Temperature/High Pressure. Midwest Research Institute.
EPA-600/2-75-020, August 1975.
3. Fulton, R. W. and S. Youngblood. Survey of High Temperature Clean-Up Tech-
nology for Low Btu Fuel Gas Processes. Aerotherm Report 75-134, January 1975.
4. Perkin, H. C. Air Pollution. McGraw Hill and Co., 1974.
5. Whitby, K. T. and B. Cantrell. Atmospheric Aerosols - Characteristics and
Measuremental Sensing and Assessment. Las Vegas, Nevada, September 1975.
6. Waggoner, ;A. P. and R. J. Charlson. Aerosol Characteristics and Visibility.
Final Report, EPA Grant // R-800-665, 1975.
7. Altshuller, A. P. Principal Species in Atmospheric Fine Particulate Matter.
Minutes of Meeting, EPA Air Pollution Chemistry and Physics Committee,
Alexandria, Va., 1975.
8. Altshuller,, A. P. Characteristics of the Chemical Composition of the Fine
Particulate Fraction in the Atmosphere (Draft). U.S. Environmental Protec-
tion Agency* Research Triangle Park, N.C.
9. Hiddy, G. M. Characterization of Aerosols in California, (ACHEX)... Final
Report to Air Resources Board, State of California, Vol. I-IV, 1974.
10. Abbott, J. H. and D. C. Drehmel. Control of Fine Particulate Emissions
from Stationary Sources. U.S. Environmental Protection Agency, IERL-RTP,
Chemical Engineering Progress, December 1976, p. 47.
51
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/7-77-013
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
EPA and ERDA High-Temperature/High-Pressure
Particulate Control Programs
5. REPORT DATE
February 1977
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
R.A. Kennedy, H. Dhillon, andJ.B. Truett
9. PERFORMING ORGANIZATION NAME AND ADDRESS
The Mitre Corporation
Metrek Division
McLean, Virginia 22101
10. PROGRAM ELEMENT NO.
EHE623
11. CONTRACT/GRANT NO.
68-01-3539, Task 4
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final; 6-11/76
14. SPONSORING AGENCY CODE
EPA/600/13
is.SUPPLEMENTARY NOTES j.ERL_RTp project officer for this report is D. C. Drehmel, Mail
Drop 61, S1S/54S-8411 Ext 2925.
16. ABSTRACT
The report describes and compares current projects sponsored by EPA
and the U.S. Energy Research and Development Administration (ERDA), relating to
the control of particulate matter in fuel gas streams at high temperatures (1000 to
200'J F) and high pressures (5 atm and greater). The descriptions document each
project (indicating the sponsor, contractor, funding, project officer, duration, and
milestones) and provide a narrative statement of objectives and technology involved.
Project descriptions provide bases for identifying overlap or duplication, and indi-
cate areas not addressed by either Agency. Descriptions were obtained from docu-
mentation provided by the two Agencies and from discussions with Agency contractor
representatives. Comparison of EPA and ERDA activities for possible overlap and
omissions is summarized in the conclusions which indicate that there is little evidence
of any overlap or duplication. Since the composite effort of both Agencies is not
large, some important areas of interest are not addressed. No projects are dedicated
exclusively to characterization and study of aerosol mechanics; however, one such
EPA-sponsored study was completed recently. Some characterization work is done at
ERDA, incident to advanced energy systems development. Development of instrumen-
tation is limited and does not extend to the expected 1000-psig operating range.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Air Pollution
Fuels
Gases
Particles
Air Pollution Control
Stationary Sources
Particulate Control
High Temperature
High Pressure
Fuel Gas Streams
13B
2 ID
07D
13. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS /This Report)
Unclassified
21. NO. OF PAGES
52
20. SECURITY CLASS (Thispage}
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
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