EPA-340/1-80-018
Annotated Bibliography of
Literature on Flue Gas
Conditioning (1966-1980)
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of General Enforcement
Division of Stationary Source Enforcement
Washington, DC 20460
March t981
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DISCLAIMER
This report has been reviewed by the Division of Stationary Source
Enforcement, U. S. Environmental Protection Agency, and approved
for publication. Approval does not signify that the contents
necessarily reflect the views and policies of the U. S. Environ-
mental Protection Agency, nor does mention of trade names or
commercial products constitute endorsement or recommendation for
use.
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ABSTRACT
This report presents a comprehensive bibliography of literature
on Flue Gas Conditioning. It was developed through search of
numerous data bases including Air Pollution Abstracts (APTIC),
Chemical Abstracts, Engineering Index (COMPENDEX), Environmental
Abstracts (ENVIROLINE), National Technical Information Service
(NTIS), etc. Publications of Electric Power Research Institute,
Edison Electric Institute and Department of Energy are also
included. Information is provided on the assigned U.S. patents
related to Flue Gas Conditioning. The literature is organized
under four separate categories: (i) general theory, (ii) specific
methods and agents, (iii) specific installations using FGC, and
(iv) legal and regulatory aspects.
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CONTENTS
Abstract
Acknowledgement
1.0 Introduction
2.0 FGC Literature..
2.1 General Theory
2.2 Specific Methods and Agents,....,
2.3 Specific Installations Using FGC,
Page
iii
vi
1
1
2
47
96
2.4 Legal and Regulatory Aspects 123
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ACKNOWLEDGEMENT
The authors are grateful to Mr. Timothy Dempsey of EPA library
services for his assistance in searching useful data bases. A
special note of thanks is due to Mr. Mark Antell, EPA Task
Manager, for excellent coordination and help in support of our
effort.
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ANNOTATED BIBLIOGRAPHY OF
LITERATURE ON FLUE GAS CONDITIONING
1.0 Introduction
Many coal-fired power plants are switching from high to low sulfur
coal to meet sulfur dioxide emission regulations. However, low
sulfur coal produces high resistivity fly ash which is difficult to
collect by an electrostatic precipitator (ESP), and the utilities
are faced with problems of excessive particulate emissions.
Flue Gas Conditioning (FGC) presents a potential solution to the
problem of high resistivity fly ash collection. It usually involves
the injection of a chemical into flue gas to control the electrical
resistivity of the ash and improve its collection in an electro-
static precipitator. it may also serve two more purposes: (i) to
increase the cohesiveness of fly ash particles deposited in a pre-
cipitator and (ii) to improve the electrical properties of the gas
stream flowing between discharge wires and collection electrodes.
2.0 FGC Literature
A considerable amount of work has been done in this increasingly im-
portant area of particulate emissions control. Several different
chemicals have been successfully used for conditioning. To develop
a comprehensive bibliography on FGC literature, the following data-
bases were searched through EPA library services:
a.
b.
c.
d.
e.
Air Pollution Abstracts (APTIC)
Chemical Abstracts
Engineering Index (COMPENDEX)
Environmental Abstracts (ENVIROLINE)
National Technical Information Service (NTIS)
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Publications of Electric Power Research Institute (EPRI), Department
of Energy (DOE) and Edison Electric Institute (EEl) are also in-
cluded in this report. York in-house library is a member of
Southwestern Connecticut Library Council. It provided several
useful citations and all patent information to complete the
literature search.
The literature is organized under the following four separate cate-
gories:
a. General Theory
b. Specific Methods and Agents
c. Specific Installations using FGC
d. Legal and Regulatory Aspects
Many citations deal with more than one category and are, therefore,
listed more than once under separate topics.
2.1 General Theory
Flue gas conditioning technology to reduce the fly ash resistivity
has been known for more than fifteen years, in both the U.S. and
Europe. However, it has gained significant importance only after
1970. Since then, considerable attention has been paid to this area
by many private industries. Many research projects have been
carried out to better understand the mechanism of FGC.
Flue gas conditioning has been extensively discussed in symposiums
on particulate emissions control. This, along with the research
work, has resulted in many publications on the subject. The
citations listed in this section deal with the general theory of
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FGC. They discuss the basic mechanisms of. action of PGC as well as
its various effects on fly ash, viz., resistivity modification,
enhanced cohesiveness, and space charge effects. They also
investigate the conditions under which good results are obtained and
the common problems associated with its use. Each citation is
accompanied by its abstract.
1.
Aimone, R.J., Bourke, B.T., Stuparich, J.J. , "Experience with
Precipitators When Collecting Ash from Low Sulfur Coals",
Presented at the 36th Annual Meeting of American Power Con-
ference, Chicago, IL, April 1974.
Abstract;
This paper discusses many of the problems with
precipitators when collecting fly ash from low sulfur
coals. Also discussed are the techniques for combating
these problems including relatively low gas velocity, use
of suitable rapping method, high degree of electrical
sectionalization, use of double half-wave power with
automatic controls and flue gas conditioning.
2. Archer, William E., "Flyash Conditioning Update", Power
Eng., Vol. 81, No. 6, June 1977.
Abstract;
An account is given of the use of flue gas conditioning by
injecting trace amount of 803 into the flue gas stream
ahead of the electrostatic precipitator in order to reduce
the resistivity of the flyash to a level at which the
precipitator can function normally.
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Atkins, R.S., Bubernick, D.V., "Keeping Fly Ash Out of the
Stack", Environmental Science and Technology, Vol. 12, No. 6,
June 1978.
Abstract:
First, two engineers from a company long in the
precipitator field explain the functions of these systems,
and what some of the design and construction methodology
is. Then two other engineers from EPA and a leading
research institute tell how they tested a hot-side
precipitator, and what they found.
Atkins, Richard S., and David H. Klipstein, "Improved Precipit-
ator Performance by 863 Gas Conditioning", Natl. Eng., Vol. 79,
No. 11, Nov. 1975.
Abstract:
Gas conditioning can dramatically improve the performance
of electrostatic precipitators at relatively low cost. It
can be applied to precipitators already in operation and
to new units. It involves injecting small quantities of a
chemical into the flue gas which optimizes the electrical
resistivity of fly ash, making it more amenable to
collection in a precipitator. Precipitator performance is
discussed. Dust conductivity may be increased by small
quantities of easily ionized chemicals called conditioning
agents. Typically, conditioning compounds for each type
of dust are found by educated trial and error. The most
common conditioning agents are sulfuric acid and ammonia.
There are several types of commercial sulfur trioxide gas
conditioning systems: evaporation of liquid 8037
catalytic conversion of sulfur dioxide; vaporization of
sulfuric acid; and sulfur burning followed by the
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5.
catalytic conversion of SO2 to SO3. The simplest is a
liquid 303 gas conditioning system. Sulfuric acid is
heated above its boiling point, vaporized, and diluted
with air in acid vaporization. Then it is injected into
the flue ahead of the precipitator. About 70 to 75% of
SO2 can be converted to SO3 by catalytic conversion. The
resultant mixture will then be injected into the flue
gas. Sulfur burning is also described. In situ, portable
test, mobile, and computer equipment is discussed. When
switching to a lower sulfur fuel, existing precipitators
are unlikely to maintain performance without either
increased precipitator capacity, reduction in boiler
operating rate, or gas conditioning.
Baxter, Walter A., "Recent Electrostatic Precipitator
Experience with Ammonia Conditioning of Power Boiler Flue
Gases", Journal of the APCA, Vol. 18, No. 12, December 1968.
Abstract;
This paper discusses experiments done by Koppers Company '
with ammonia conditioning of power boiler flue gases for
the purpose of improving the precipitability of the
emitted fly ash. Chemical reactions resulting from
ammonia injection are postulated. Measurements on three
pulverized coal and two cyclone fired boilers, all of
which emit acidic ash, are described. In all five cases,
considerable but varying, increase in precipitator power
input and collection efficiency resulted when gaseous
ammonia in the amount of 15 ppm was injected between the
economizer and air preheater. The conditioned fly ash
showed decreased acidity and inconsistent change in
electrical resistivity. Unless air heater temperatures
were unusually high (>40o°F), the tendency of the air
heater to plug was an additional, but unwanted, result.
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6.
At one station with a high air heater outlet
temperature, ammonia injection has been adopted as a
permanent solution to community pressure for a reduction
of stack discharge. Ammonia injection downstream of the
air heater produced no effect. Future plans are presented
to continue the program beyond results described here.
Bennett, R.P., "Fly Ash Conditioning to Improve Precipitator
Efficiency with Low Sulfur Coals", ASME Publication
76-WA/APC-8, December 1976.
Abstract;
The use of blended chemical agents to condition coal fly
ash to improve electrostatic precipitator efficiency and
reduce particulate emissions has been subjected to
extensive field trials to verify its broad application as
a possible economic solution to pollution problems for the
electric utility industry. These chemical conditioning
agents have been used with a variety of.low to medium
sulfur coals resulting in precipitator efficiency
improvements of 50 to 90 percent. Emissions compliance
levels are often obtained as a result of this treatment.
The effectiveness of this system has been demonstrated on
units from 25 to 750 MW. Case history examples illustrate
the types of units treated and the extent of emissions
reductions obtained.
Bennett, R.P., Kober A.E., "Chemical Enhancement of Electro-
static Precipitator Efficiency", Symposium on the Transfer and
Utilization of Particulate Control Technology, EPA-600/7-
790044a, February 1979.
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Abstract;
8.
It has been shown previously that chemical conditioning of
flyash can offer an immediately available alternative to
retrofit precipitators, baghouses, or other methods of
mechanical collection and usually provides compliance
emissions at relatively low operating cost. The equipment
required involves minimum capital investment and can
usually be installed in a matter of weeks with no
significant unit downtime being involved.
It has now been demonstrated that the technique of
chemical conditioning can be expanded into a previously
untried area with the successful treatment of high-sulfur
coals, of hot precipitators, and of low-sulfur coals
utilizing a dual-injection system to provide minimum
emissions and minimum opacity. Ready availability and
minimum total costs are two advantages of this method.
The use of new conditioning agents for these processes is
continually being examined for further advances in the
state of flue gas chemical conditioning.
Bickelhaupt, R.E., "Sodium Conditioning to Reduce Fly Ash
Resistivity", EPA/650/2-74-092, October 1974.
Abstract:
The resistivity of fly ash is often too high under a
particular set of operating conditions to permit the most
efficient use of an electrostatic precipitator. A variety
of substances> generally referred to as conditioning
agents, can be added to the boiler or to the effluent gas
downstream to attenuate the high resistivity. The report
gives the results of a review of recent research,
including the results of two field tests of sodium
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conditioning, on the effects of sodium content on the
electrical resistivity of coal fly ash. It presents a
procedure for calculating the amount of sodium that must
be added to reduce fly ash electrical resistivity to a
desired value. It discusses advantages and disadvantages
of sodium conditioning for reducing fly ash resistivity.
Bickelhaupt, R.E., "Effect.of Chemical Composition on Surface
Resistivity of Fly Ash", EPA/600/2-75-017, August 1975.
Abstract:
Electrical resistivity is one of the critical parameters
influencing the collectability of fly ash by electrostatic
precipitation. This report discusses research designed to
acquire additional knowledge about the surface conduction
process. Transference experiments revealed that the
alkali metal ions serve as charge carriers. It was
concluded that the attack by certain environmental
species, water and acid, on the surface of the glassy ash
mobilizes the alkali metal ions. A correlation was
established between the magnitude of maxium surface
resistivity and the concentrations of lithium, sodium,
potassium and iron. The correlation offers a possible
means of estimating the resistivity of an ash from the
chemical analysis for a given set of environmental
conditions.
10. Bickelhaupt, R.E., "Measure of Fly Ash Resistivity Using Simu-
lated Flue Gas Environments", EPA/600/7-78/035, March 1978.
Abstract:
The report, describing the apparatus and laboratory
procedures used to determine resistivity for a number of
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fly ashes under a variety of test conditions, supports
research to develop a technique for predicting fly ash
resistivity from chemical analyses of coal and coal ash.
This effort requires considerable knowledge regarding the
relationship between resistivity and several coal and ash
properties. -In particular, the report relates the
experimental problems encountered when attempts were made
to determine the effect of sulfur trioxide on
resistivity. Equipment and procedures were developed to
solve this problem. The report describes the modified
apparatus and technique and illustrates the type of data
acquired.
Bickelhaupt, R.E., Dismukes, E.B., Spafford, R.B., "Flue Gas
Conditioning for Enhanced Precipitation of Difficult Ashes,
Final Report", EPRI-FP-910, October 1978.
Abstract:
A review of the available prior investigations indicates
that the effectiveness of ammonia and triethylamine as
conditioning agents used to improve the performance of
electrostatic precipitators has been inconclusive. When
successful conditioning has occurred, it sometimes has
been impossible to determine the process by which the
conditioning agent affects the performance. The objective
of this research was to examine the ability of these two
conditioning agents with respect to the attenuation of
resistivity and the suppression of back corona.
Conventional resistivity determinations were made using
simulated flue gas environments containing the subject
agents. A second approach utilized a wire-guarded plate
apparatus for the determination of voltage-current
relationships. With regard to the effect these
conditioning agents have on the electrical characteristics
of a precipitator, the laboratory data suggest only an
attenuation of resistivity. A mechanism by which these
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agents enhance conduction is hypothesized. The usefulness
of triethylamine and particulary ammonia is severely
limited by temperature and ash composition. The
effectiveness of both agents is also influenced by the
sulfur oxides present. The voltage-current data suffered
from several experimental difficulties. In general, the
data support the observation that these agents are capable
of reducing resistivity under certain limiting
conditions. Experimental problems prevented the
observation of space charge effects related to ammonia
injection that have been identified during field testing
performed by one of the authors and reported elsewhere.
Borsheim, R., Bennett, R.P., "Chemical Conditioning of Low
Sulfur Western Coal", Presented at 39th Annual Meeting,
American Power Conference, Chicago, IL, April 1977.
Abstract;
This paper gives the results of conditioning program
carried out at Corette plant of Montana Power Company.
Chemical conditioning of fly ash allowed boiler operating
loads to be raised from an average of 148 MW to full 163
MW net load without exceeding particulate emissions and
plume opacity limits.
13. Breich, E.W., "Flue Gas Conditioning for New Electrostatic Pre-
cipitators/An Economic Evaluation", Presented at the Symposium
on the Transfer and Utilization of Particulate Control Tech-
nology, University of Denver, Denver, CO, July 24-28 1978.
Abstract:
This paper discusses the methods and associated costs of
alternative collectors for the collection of low sulfur
coal fly ash on an 800 MW unit. Systems evaluated
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include: cold side precipitators, hot side precipitators,
cold side precipitator with Flue Gas Conditioning, fabric
filters, and flue gas desulfurization systems (scrubbers).
In the case of the scrubber, it is assumed that the fly
ash is removed by either a precipitator system or fabric
filter before entry into the scrubber for removal of
sulfur oxides.
14. Breisch., E.W., "Method and Cost Analysis of Alternative
Collectors for Low Sulfur Coal Fly Ash", Symposium on the
Transfer and Utilization of Particulate Control Technology,
EPA-600/7-79-044a, February 1979.
Abstract;
Flue Gas conditioning in conjunction with a conventionally
sized precipitator is shown to be the most cost-effective
means of collecting low sulfur coal, high resistivity fly
ash. The results obtained with flue gas conditioning are
both predictable and dramatic.
A case in point is the experience which Public Service
Company of Colorado has had with vendors for their new
99.2% efficient precipitator installation at Arapahoe
Station Unit 1. PSCC received bids from a number of
vendors for hot side precipitators and for cold side
precipitators with and without conditioning. The Specific
Collecting Areas proposed ranged from 295 to 334.5 for the
hot gas side precipitator. The bids for .cold side ranged
from an SCA of 688 with no conditioning, down to 279 with
conditioning. PSCC chose the conditioned precipitator and
after a year's operation of the combined installation,
acceptance tests were conducted. The results were even
better than the original conformance tests. Emissions in
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Ib/MM BTU's were .0161; well below the statutory limit of
.10. Average outlet grain loadings were only .0079
gr/dscf.
15. Brennan, H., Reveley, R.L., "Flue Gas Conditioning with Sulfur
Trioxide to Improve Precipitator Performance", Proceedings of
American Power Conference, Detroit Edison Company, Detroit, MI,
1977.
Abstract;
Unavailable
16. Brown, T.D., Lee, G.K., Reeve, J., Sekhar, N., "Improved
Electrostatic Performance by Use of Flyash Conditioning
Agents", Journal of the Institute of Fuel, Series 51, Issue
409, 1978.
Abstract:
Unavailable
17. Cheremisinoff, P.N., "Advanced Flyash Conditioning Technology",
Power Engineering, November 1977.
18.
Abstract;
Effects of high resistivity of flyash on the precipitator
performance are discussed. Improvements in precipitator
performance can be accomplished by new conditioning agents
which not only control the conductivity of flyash but also
increase the particle-to-particle cohesion and the space
charge.
Cohen, Murray S., Bennett, R.P., "Case Studies on Chemical Flue
Gas Treatment As A Means of Meeting Particulate Emission Regul-
ations", ACS Symposium Ser., No. 109, Miami Beach, FL, Sept-
ember 14, 1978.
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Abstract;
A description is given of the chronological development of
two streams of Federal legislation, one regulating the
emissions of particulates from large stationary sources
and the other seeking to reduce the dependence upon
foreign oil imports. It shows how these regulations
offered an opportunity for the development and
commercialization of a new technology called chemical
Flue Gas Conditioning. An explanation is given of the
operation of existing particulate control devices, notably
the electrostatic precipitator (ESP). A description is
also given of how particulate capturability can be
improved by chemical treatment and then how a proprietary
formulation has lead to the treatment of a wide variety of
fuels in both cold and hot side ESP units is illustrated.
Evidence is also presented showing that fine particular
emissions, i.e., those implicated in health effects, could
be significantly reduced.
19. Cook, R.E., "Sulfur Trioxide Conditioning", J. Air Pollution
Control Association, Vol. 25, No. 2, February 1975.
Abstract:
Burning of western low sulfur coal, to reduce sulfur oxide
emissions, has resulted in decreased electrostatic
precipitator collection efficiencies. In an effort to
restore precipitator performance a flue gas conditioning
program was established. This paper discusses experience
with sulfur trioxide as a flue gas conditioning agent.
Testing at State Line Station has proven that sulfur
trioxide conditioning can effectively be used to improve
precipitator performance when burning low sulfur coals.
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20. Dirt, P., Coughlin, R.W., "Improving Efficiency of
Electrostatic Precipitation by Physicochemical Modification of
the Electrical Resistivity of Flyash", AICHE Journal, Vol. 22,
No. 4, July 1976.
21.
Abstract;
Theory and experiment show that lowered resistivity of fly
ash, frequently caused by adding conditioning agents to
flue gas to improve efficiency of electrostatic
precipitation, is caused by capillary condensation of
liquid at the contact points of ash particles, thereby
providing additional pathways for flow of electrical
current.
Dismukes, E.B., "A Study of Resistivity and Conditioning of Fly
Ash", EPA-R2-72-087, February 1972.
22,
Abstract;
An experimental study was made on the injection of 803 and
H2SO4 gaseous conditioning agent to alleviate the problem
of high electrical resistivity of fly ash.
Dismukes, E.B., "Conditioning of Fly Ash with Sulfamic Acid,
Ammonium Sulfate and Ammonium Bisulfate", EPA/650/2-74-114,
October 1974.
Abstract;
The report summarizes recent experience with three
agents—sulfamic acid, ammonium sulfate, and ammonium
bisulfate—used to regulate the electrical resistivity of
fly ash in electric generating'stations to ensure
satisfactory collection of fly ash in electrostatic
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precipitator (ESP's). It presents information about the
effectiveness of theses agents in pilot- and full-scale
ESP's. It also presents the limited information available
from practical trials of these agents concerning their
conditioning mechanisms. It discusses in detail the
fundamental physical and chemical properties of the agents
that are relevant to fly-ash conditioning. From this
information and the results of ESP tests, the report
offers tentative conclusions about conditioning
mechanisms. Finally, the report briefly discusses the
economic aspects of using each of the agents as a
conditioning substitute for sulfur trioxide.
23. Dismukes, E.B., "Conditioning of Fly Ash with Ammonia" EPA-650/
2-75-016, 1975.
Abstract:
Field tests at Tennessee Valley Authority coal-fired power
plants involving the effect of flue gas conditioning with
ammonia on the fly ash collection efficiency of
electrostatic precipitators are described, with particular
emphasis on the mechanisms of collection enhancement.
Ammonia conditioning appears to improve the efficiency of
fly ash precipitation through two mechanisms. The first
consists of a space-charge effect, and the second involves
an increase in the cohesiveness of fly ash. The first
occurs with fly ash having low to moderately high
resistivities, while the second mechanism is observed only
with low-resistivity fly ash. Evidence of each mechanism
is observed only under circumstances where the properties
of the coal and the fly ash as well as the temperature of
the flue gas permit significant concentrations of sulfur
trioxide (2-11 ppm) to occur in the off gas. The reaction
of ammonia with SO3 to produce ammonium sulfate or
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ammonium bisulfate appears to be a key event in the
occurrence of either conditioning process.
24. Dismukes, E.B, "Conditioning of Fly Ash with Sulfamic Acid",
EPA-650/2-75-016, 1975.
Abstract:
Pilot plant and field tests of sulfamic acid flue gas
conditioning for the reduction of fly ash resistivity and
increased electrostatic precipitator collection efficiency
are reviewed. Sulfamic acid appears to be a worthy sub-
stitute for sulfur trioxide as a flue gas conditioning
agent, as evidenced by increases in collection efficiency
obtained at various coal-burning plants with with high-
resistivity fly as problems. The primary advantages of
sulfamic acid are its ease of handling and freedom from
hazard; the high cost of the chemical is its main dis-
advantage. The mechanisms by which sulfamic acid acts as
conditioning agent are not clearly established.
25. Dismukes, E.B., "Conditioning of Fly Ash with Sulfur Trioxide
and Ammonia", EPA-600/2-75-015, August 1975.
Abstract ;
The use of sulfur trioxide and ammonia as flue gas
conditioners to improve the electrostatic precipitation of
fly ash generated in coal-burning power plants was
investigated. The primary role of 303 in improving
collection appeared to be related to a lowering of fly ash
resistivity from the excessive values associated with ash
from low-sulfur coals . Ammonia conditioning appeared to
involve a space charge of the precipitator as well as an
increase in the cohesiveness of the collected as at
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times. Satisfactory sites of injection were the flue gas
ducts in locations upstream from the precipitator,
upstream from the combination of a precipitator and
mechanical collector, and between the two types of
collectors. Fly ash was successfully conditioned at
temperatures ranging from 110 to at least 160°C.
26. Dismukes, E.B., "Techniques for Conditioning Fly Ash",
Conference on Particulate Collection Problems in Converting to
Low Sulfur Coals, EPA 600/7-76-016, October 1976.
27.
Abstract;
Conditioning of fly ash is discussed in connection with
electrostatic precipitators from several points of view:
the purposes served, the types of chemicals used, and
their "mechanisms of action. Major emphasis is given to
resistivity modification with sulfur trioxide and other
agents. Comments are also made on alternative
conditioning mechanisms: increasing the cohesiveness of
deposited fly ash to minimize reentrainment and improving
the electrical properties of the flue gas to increase the
efficiency of fly ash collection.
Dixit, S.N., Cuisia, D.G., "Additives for Coal", Combustion
Vol. 49, No. 6, December 1977.
Abstract;
With proper selection and control of fuel additives,
fireside treatment in operating power plant installations
can produce beneficial effects. Using an advanced stack
gas sampler and an acid dewpoint meter, several functions
of coal additives were demonstrated during actual field
application. Coal additives are capable of reducing acid
_
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additives are capable of reducing acid dewpoint
temperature of the flue gas; hence, minimizing boiler cold
end corrosion; and substantially reducing smoke density
and particulate loadings of the stack. Moreover, it was
shown that coal additive can modify the fireside deposits
to a more desirable chemical composition.
28. "Flue Gas Conditioning", Environment Science and Technology,
Vol. 12, No. 13, December 1978
Abstract:
Low sulfur coals are increasingly used because of
stringent air pollution control restrictions on sulfur
oxide emissions. However, low sulfur coals can present
other problems, such as flyash that is hard to capture
using an electrostatic precipitator. One solution to this
problem is to inject a chemical into the flue gas to
condition the flyash. Some recent developments indicate
that full federal acceptance of the flue gas conditioning
technology may not be too far off. Representative Paul
Rogers (D-FLA) has requested that EPA investigate chemical
conditioning with the possible goal of requiring flue gas
treatment under authority granted the agency under the
Clean Air Act of 1977. Several instances of the use of
flue gas conditioning by U.S. companies are described.
29. Frisch, N.W., Dorchak, T.P, "Impact of Fuel on Precipitator
Performance", Pollution Engineering, Vol. 10, No. 5, May 1978.
Abstract;
Variations in the chemical content of coal used as a fuel
affect the ability of precipitators to remove particulates
from flue gas resulting from coal combustion. For
example, ash having a high electrical resistivity may
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30.
require a much larger precipitator than ash of a low
resistivity requires. High resistivity ash may shorten
the component life of precipitators. Precipitator
performance must be considered in assessing fuel sources,
and optimal conditions must be provided to achieve an
appropriate resistivity level for the fuel chosen. The
roles of conductive agents, ash conditioning, and coal
blending in analysis of coal for plant performance are
explored. Resistivity data are graphed.
Green, G.P., "Operating Experience with Particulate Control
Devices", Presented at the American Society of Mechanical
Engineers, Air Pollution Control Division, National Symposium,
3rd, Philadelphia, PA, April 1973.
Abstract:
31.
Operating experience associated with the control of
particulate emissions from steam plant units burning low
sulfur, high resistivity, western coals is reviewed.
Initially disappointing collection efficiencies with
electrostatic precipitators were improved by conditioning
the flue gas with sulfur trioxide such that its
concentration in the gas to be treated was 20 ppm.
Collection efficiencies for eight different units ranged
from 37.5-94.0% before flue gas conditioning and from
51.2-97.2% after conditioning with SO3.
Jaworowski, R.J., O'Connor, M.J., "Effect of Flue Gas Con-
ditioned Fly Ash on Electrostatic Precipitator Control", Pro-
curement of the ISA Conference and Exhibition, Philadelphia,
PA, October 15-19, 1978.
Abstract:
_
Electrostatic precipitators (ESP) are designed for a
specific combination of dust fineness, resistivity, and
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32.
concentration. The ability of the ESP to cope with
changes in these parameters is limited and significant
reductions in performance often accompany changes in coal
supplies (high sulfur coal to low sulfur coal to reduce
SO2 emissions). This paper discusses the use of
precipitator control readings to diagnose problems
resulting from changes in fly ash resistivity, particle
size distribution, and concentration. The use of chemical
conditioning agents to overcome the adverse effects of
these changes is discussed and examples of successful
applications are given.
Kanowski, S., Coughlin, R.W., "Catalytic Conditioning of Fly
Ash Without Addition of SO3 from External Sources",
Environmental Science Technology, Vol. 11, No. 1, January 1977.
Abstract:
Data and experimental results are presented to demonstrate
that catalytic oxidation of sulfur dioxide (SO2) at the
low concentrations normally present in flue gas from low
sulfur coal can produce sulfur trioxide SO3 in
concentrations sufficiently large to cause good
conditioning by significantly lowering the resistivity of
fly ash. This was accomplished by disposing catalysts in
streams of SO2 bearing flue gas and measuring the effects
of the gases so treated on the resistivity of carbon-free
fly ash obtained from several different coal-fired power
stations. Concentrations of SO2 and 803 were measured by
gas sampling and chemical analysis. The effects of
moisture and temperture were also investigated.
33. Klipstein, D.H., "Improved Precipitator Performance by Gas
Conditioning", Combustion Vol. 47, No. 4, October 1975.
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34,
Abstract;
The switching from, high sulfur to low sulfur Western coals
-should they become available- will reduce SC>2 problems
but add flyash removal problems. One solution, discussed
in this article, is the role of gas conditioning which
involves the injection of small quantities of SO3 into the
flue gas to reduce electrical resistivity of fly ash, thus
making the dust more amenable to collection in the
precipitator. The fundamentals of electrostatic
precipitators are reviewed, and several types of
commercial SO3 gas conditioning systems are examined both
from the technical and economic standpoint.
Kropp, L.I., Shmigol, I.N., Chekanov, G.S., Oglesby, S.,
Bickelhaupt, R.E., "Joint US/USSR Test Program for Reducing Fly
Ash Resistivity", Journal of the APCA, Vol. 29, No. 6, June
1979.
_
Abstract;
An electrostatic precipitator preceded by a wet scrubber
was tested at the Reftinskaya Power Station. The unit
collects a high resistivity fly ash from the combustion of
low sulfur Ekibastuz coal. The operating parameters of
the precipitator were measured as well as the mass
emissions and the in-situ electrical resistivity of the
fly ash. Density, particle size distribution, electrical
resistivity, and chemical composition were determined for
collected samples of the fly ash. The fly ash was also
characterized by X-ray diffraction and scanning electron
micrpscopy. When a centrifugal wet wall scrubber .was.
installed ahead of the electrostatic precipitator, the
temperature of the flue gas entering the precipitator was
decreased and the moisture content increased. The
electrical resistivity of the fly ash was reduced by a
factor of 10, but not enough to overcome the adverse
effects of back corona in the precipitator. Lowering the
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flue gas temperature to about 85OC by the addition of a
venturi scrubber ahead of the centrifugal scrubber reduced
the electrical resistivity of the fly ash by another
factor of 10 and allowed the operation of the precipitator
without back corona.
35. Kukin, I., "Utilization of Additives in Controlled Combustion
Products", Presented at the MECAR Technical Symposium on
Combustion and Air Pollution Control, October 25, 1966.
Abstract:
Practical applications of chemical additives for reducing
air pollution with petroleum fuels are discussed.
Successful results have been achieved in the field by the
use
of additives for fuel oils, both distillate and
and nitrogen oxides. With residual fuels,
SO 2
residual fuels. The major pollutants are:, (1) black
particulate matter representing primarily unburned
hydrocarbons: (2) sulfur oxides (SO2 and SO3). With
distillate fuels, where the sulfur content generally is
below 0.5%, our primary concern is particulate matter and
to a somewhat lesser degree, carbon monoxide, aldehydes
Is, sulfur,
and 803, is the dominant consideration, although the
ability to reduce black smoke emission by means of
chemical additive is certainly a valuable contribution to
air pollution control. The three effective classes of
chemical additives are: (1) combustion catalysts, (2)
oil-ash slag modifiers, and (3) chemical neutralizing
agents. In some cases, these chemical agents can be
combined to give one or more benefits. In a recent trial
at a power plant, one of their products, SSI-3(R), reduced
the black smoke at the same time that it lowered the 803
content of the flue gas from 90 to 5 parts per million.
The case histories cited show how chemical additives are
being used to reduce air pollution and, at the same time,
make a contribution to better overall fuel utilization.
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36.
Kukin, I., "Advances In The Use Of Chemical Treatment In Air
Pollution Reduction Programs", Presented at the National
Petroleum Refiners Association Rocky Mountain Region Meeting,
Billings, MT, October 2-3, 1968, Paper RM-68-80.
Abstract:
37,
Extensive in-plant tests were made on the ability of a
fuel additive containing 25% activated manganese to keep
boiler fireside tubes clean and to reduce the sulfur
trioxide content of the flue gas. Especially good results
were obtained in pressurized furnace of 2500 psig when low
sulfur fuel oil (one percent) was burned. After three
months, the treated furnace showed a 75% reduction in the
S03 content of the flue gas and only slight tar deposits
were apparent. The deposits could be brushed off rapidly,
even by simple air lancing. Since the smaller quantities
than is the ash with magnesium oxide additives. The
manganese additive is not stoiciometrically consumed in
reactions with vanadium and sulfur oxides but regenerates
itself. It reacts with carbons and hydrocarbons to
increase the carbon dioxide content of the flue gas; it
further lowers the ignition temperature of combustible
deposits within a furnace. By eliminating soot, it
improves the appearance of stacks. Another factor
favoring the use of the additive is that it reduces the
excess air to fuel ratio.
Kukin, I., "Additives Can Clean Up Oil-Fired Furnaces",
Environmental Science Technology 1973, Vol. 7, No. 7, July
1973.
Abstract;
The addition of metal-containing additives to improve
boiler cleanliness, cut fireside and air heater corrosion,
and to reduce stack emissions and plumes is discussed. In
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general, fuel additives should provide boiler cleanliness,
high-temperature vanadium corrosion protection, prevention
of loss of operating capacity by maintaining design steam
temperature, cold end (air heater) corrosion protection,
reduction of stack emissions from hydrogen particulate
matter and sulfur trioxide, and improvement in the
handling characteristics of ash in the flue gas in oil
fired boilers equipped with precipitators and stack
collectors. The significant fuel additives in use today
usually contain magnesium oxide (with or without small
amounts of aluminum oxide or hydrate), manganese, and
magnesium oxide with manganese. The characteristics of
each of these additives is discussed, and the efficacy of
magnesium oxide additives is compared to that of manganese
additives. Handling characteristics and air emissions are
also reviewed.
38. Kukin, I., "Effects of Additives On Boiler Cleanliness and
Particulate Emissions", Procurement Int. Meet. Soc. Eng. Sci.,
1st, Tel Aviv, Israel, 1972.
Abstract:
Concentrated metal-containing additives are often used in
oil-fired furnaces to improve boiler cleanliness and
reduce the fireside and air heater corrosion-. They can
also reduce stack emissions, especially hydrocarbon
particulates and sulfur trioxide. They can improve the
handling characteristics of the ash in the flue gas in
oil-fired boilers equipped with precipitators and stack
collectors. Significant fuel additives in use today
contain magnesium oxide, manganese, or magnesium oxide
with manganese. The role of MgO as a fuel oil additive
with high sulfur and high vanadium fuels is described.
Low sulfur-low vanadium fuels often contain manganese
additives. High temperature slagging and corrosion in
oil-fired boilers is reduced with a slurry containing both
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39.
MgO and Mn in combination. Manganese additives reduce
internal boiler fouling of superheaters and reheaters at
low ash input ratios. High sulfur fuels with low Vanadium
content are preferably treated with tail end chemical
injection of an active neutralizing agent to remove 803.
Overall decrease in stack emission ideally is obtained
with a dual additive application consisting of addition of
Mn to the fuel oil and a neutralizing agent to the
economizer outlet. Manganese additives eliminate stack
smoke, particularly in refineries burning pitch or
polymerized bottoms. Corrosion and fouling from SO3 in
coil-fired units can be eliminated by aspirating an
activated neutralizing agent in powder form into the
economizer outlet of the furnace. Other uses of
additives are discussed.
Kukin, I., Bennett, R., "Chemical Control of Particulate
Emissions Through Flue'Gas Conditioning", Presented at 12th
Conference on Air Quality Management in the Electric Power
Industry, The University of Texas at Austin, TX, January 28-30,
1976.
Abstract;
This paper shows how the use of chemicals has become a
valuable, relatively simple and quickly installed method
for helping coal burning units to meet emissions
regulations. Faced with uncertain fuel supplies and
handicapped by a capital shortage, the electric utility
industry can look to increased use of sophisticated
chemical technology for solutions to pollution problems.
The proper application of chemical additives can allow
utilities to meet emission standards related to
particulates and plume opacity, at the same time often
allowing for improved efficiency and reduced fuel usage.
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40. Kukin, I., Bennett, R., "Particulate Emission Control Through
Chemical Conditioning", Combustion Vol. 48, No. 4, October
1976.
41.
Abstract;
The chemical treatment of flue gases to reduce polluting
emissions was subjected to quantitative field tests to
verify its practicality as a possible economic solution to
current energy and pollution problems for electric util-
ities. Chemical conditioning agents for the ash in the
flue gas improved electrostatic precipitator collection
efficiency by 50-90%, so that the units complied with
emission regulations. Some units have been able to oper-
ate at increased capacity while .still meeting compliance
levels. Chemical neutralization of 803 in the flue gas,
resulting in a lowered acid dew point, allows operation at
reduced exit gas temperatures. Reduced particulate emis-
sions frequently result from this safe change in
operation.
Kukin, I., Bennett, R.P., "Chemical Reduction of 803,
Particulates and NOX Emissions, J. Inst. Fuel, Vol. 50, No.
402, March 1977.
Abstract;
The chemical treatment of fuels and flue gas to reduce
polluting emissions was subjected to quantitative fields
tests to verify its practicality as a possible economic
solution to current energy and pollution problems for
electric utilities. Manganese added to a residual fuel
oil at 50 ppm reduced sulphur trioxide emissions by up to
55%. Manganese has also been effective in reducing nitro-
gen oxide emissions by as much as 31%. Chemical con-
ditioning agents for the ash in the flue gas of coal-fired
units were used to improve electrostatic precipitator
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42.
precipitator collection efficiency by 50-90%, so that the
units complied with emission regulations. Examples from
case histories illustrate how environmental protection can
be obtained, at least with regard to SO3, particulates and
NOX, without incurring large capital expense.
Kukin, I., Nelson, H., "The Economics of Chemical Conditioning
for Improved Precipitator Performance", Public Util. Forth,
September 23, 1976.
Abstract;
The result of power companies switching from over 2%
sulfur content coal to low sulfur coal has frequently been
a reduction of electrostatic precipitator efficiency,
resulting in particulate emissions exceeding limits.
Chemical treatment can bring the resistivity of fly ash to
the level required for high efficiency operation of the
electrostatic precipitator. The multifunctional systems
capable of optimizing fly ash resistivity, flue gas space
charge, and fly ash particle size distribution are the
most effective. Case histories illustrate the ability of
these chemcial systems to obviate the need for
multimillion dollar precipitator retrofits. Further
benefits are to be expected in new plant designs, where
savings in capital and operating costs of chemically
treated fly ash permit use of smaller, lower cost
electrostatic precipitators.
Flue gas-fly ash conditioning systems do not contribute
sulfur oxides to stack gases.
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43. Lederman, P.B., Bibbo, P.B., Bush, J. , "Chemical Conditioning
of Ply Ash for Hot-Side Precipitation", Symposium on the
Transfer and Utilization of Particulate Control Technology, EPA
600/7-79-044a, February 1979.
Abstract;
The concerns over universal application of hot
precipitators to certain low alkali, low sulftfr western
coals, which emerged when performance problems on a few
installations in the west were encountered (Columbia,
Comanche, Hayden), have now been eliminated with the
development of practical and proven hot precipitator
conditioning technology. Sodium conditioning has been
proven in the field as the chemical modifier of choice for
hot precipitators. It is economically attractive compared
to other means of upgrading marginal precipitators. This
technology should be considered for new units to provide
conditioned precipitator units capable of operating on
difficult ashes, with the added benefit of some SOX
removal, at lower costs than systems not utilizing
chemical conditioning.
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44.
Livengood, C.D., Farber, P.S., Wong, S.H., "Environmental
Control Strategies for Coal-Fired Power Plants: A Comparative
Evaluation", National conference on energy and the environment,
Cincinnati, OH, USA, 31 October 1977.
Abstract:
45.
An ongoing project has been established at Argonne
National Laboratory for the purpose of assessing the
implications of environmental control technologies for the
coal-to-electricity process from a detailed engineering
and cost point of view. In order to place these
assessments in the proper perspective, it is helpful to
conduct comparative evaluations of their effectiveness
from a total system viewpoint, taking into account
different geographic, environmental, and regulatory
constraints. This paper presents some of the results of
the initial comparisons carried out by the project. The
focus is on control of airborne emissions by presently
available technology, as this has been the principal area
of investigation thus far. The results point out that
there are usually several cost-competitive routes to
achieving compliance with existing regulations. However,
these routes generally have differing total impacts,
particularly offsite, which will become of greater
significance as new regulations force lower levels of
on-site effluents.
Martin, G.B., D.W. Pershing, and E.E. Berkau, "Effects of Fuel
Additives on Air Pollutant Emissions from Distillate-Oil-Fired
Furnaces", Environmental Protection Agency, Research Triangle
Park, NC, Office of Air Programs, Pub-AP-87, June 1971.
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Abstract;
The use of fuel additives to control air pollution from
distillate-oil-fired systems was examined. The additives
tested were commercially available, proprietary
formulations; each additive was analyzed for chemical
composition and was screened for effect on emission
characteristics. Fewer than 10% of the additives affected
any pollutant reduction, whereas more than 20% increased
emissions of at least one pollutant. In a few cases,
metallic additives substantially reduced particulate
emissions, but produced a high concentration of metal
compounds in the flue gas. Additives did not reduce
emissions of carbon monoxide, unburned hydrocarbons,
sulfur oxides, or nitrogen oxides.
46. Matts, S., "Cold-Side Electric Precipitators for High-
Resistivity Fly Ash Require Different Design Philosophy",
EPA-650/2-75-016, 1975.
Abstract:
European versus American designs for electrostatic
precipitators are discussed in economic terms, with
particular reference to the use of cold-side electrostatic
precipitators for the collection of high-resistivity fly
ash. Below a certain temperature of the flue gas being
treated, the dust components absorb increasing amounts of
moisture, resulting in a decrease in resistivity. The
peak resistivity occurs around 150°C, i.e., close to
normal operating temperatures after the air heater.
Cold-side precipitator operation using less-sectionalized
European precipitators is more economical than hot-side
precipitator operation for American fly ashes.
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47. Mcllvaine, R.W., "New Developments and Trends in Air Pollution
Control Equipment", Filter Sep, Vol. 17, No. 1, January-
February 1980.
Abstract;
In fabric filtration, developments include a hybrid
precipitator fabric filter, use of a fabric filter with
spray tower to remove SO2 to recoverable products,
commercialization of electrostatically augmented
scrubbers, and improvements in corrosion resistant
materials. Developments in electrostatic precipitators
include precharging devices, new flue gas conditioning
techniques, and methods of charging. The importance of
these new techniques and predictions for future use are
discussed.
48. McRanie, R.D., J.M. Craig, and G.O. Layman, "Evaluation of
Sample Conditioners and Continuous Stack Monitors for the
Measurement of Sulfur Dioxide, Nitrogen Oxides and Opacity in
Flue Gas from A Coal-Fired Steam Generator", Southern Services,
Inc., Birmingham, AL, Research Department, February 1975.
Abstract:
The effectiveness of sample conditioners and continuous
stack monitors for the measurement of sulfur dioxide,
nitrogen oxides, and opacity in flue gas from a coal-fired
steam generator is reported. Individual evaluations of
the seven sample conditioners, nine SO2 analyzers, nine
NOX analyzers, and two opacity monitors included are
presented. Analyzer accuracy and sample conditioner
influence testing formed an integral part of the
evaluation. Reliable and accurate continuous stack
monitoring systems cannot be purchased off the shelf from
any manufacturer. They must be specified to sample
-------
conditioner recommended for use on a coal-fired steam
generator. It seems to have no effect on the components
of interest in flue gas. The analyzers determined to be
most satisfactory with the SSI sample conditions for S02
are DuPont/ Mine Safety Appliances, and Beckman; for NOX
Thermo Electon and DuPont, and for opacity Lear Siegler.
Design and operation recommendations for a monitoring
system are included and the analytical techniques used in
continuous stack monitoring are discussed.
49. Midkiff, L.A., "Flue-Gas Conditioning Upgrades Performance,
Cuts Down Size of Precipitators", Power Vol. 123, No. 4, April
1979.
50.
Abstract;
Chemical enhancement of precipitator efficiency, once
limited to low-sulfur retrofit applications, is now being
designed into new units. Flue gas conditioning
techniques, their mechanisms,and uses are described.
Flue-gas conditioning began with the use of moisture to
lower ash resistivity. Today's techniques, however,
include modification of particle size, and of the space
charge in the gas phase. Hot-side as well as cold-side
precipitators can often benefit from flue gas treatments
that are properly applied. Flyash with a resistivity of
109-1010ohm-cm is considered ideal for collection.
Methods of lowering the resistivity of the dust, such as
the use of a hot-side precipitator, or chemical
conditioning in the cold-side precipitator, are
discussed. Low-resistivity conditioning and space-charge
conditioning are finally described.
Morris, E.B. and J.L. Schumann, "Condition F-lyash with
Synthetic SO3", Power, Vol. 118, No. 7, July 1974.
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Abstract:
51.
The conditioning of fly ash with synthetic sulfur trioxide
is discussed. It enables an electrostatic precipitator to
achieve normal collection efficiencies when cleaning flue
gas from boilers burning low sulfur, high ash coals. The
injection of minute quantities of SO3 reduces the
electrical resistivity of the fly ash to values below the
critical level of lo" ohms-cm. These S03 quantities
range from 10 to 30 ppm by volume of the flue gas. On
site synthesis eliminates the need for storing or handling
either sulfuric acid or liquid SO3. it is more economical
than installing new hot precipitators, wet scrubbers, or
special low temperature electrostatic precipitators
designed for low sulfur coal. Existing plants can upgrade
the collection efficiency of their electrostatic
precipitators to meet new particulate codes while
continuing to burn economical low sulfur coal.
Nekervis, R., J. Pilcher, J. Varga Jr., B. Gonser, and J.
Hallowell, "Process Modifications for Control of Particulate
Emissions from Stationary Combustion, Incineration, and Metals
(Final Report)", EPA-650/2-74-100, October 1974.
Abstract:
The state of process modifications for controlling fine
particulate emissions from stationary combustion sources
(electrical utilities and industrial processes), municipal
incinerators, iron and steel plants, ferro-ally plants,
and nonferrous metal smelters (zinc plants, copper
smelters, and aluminum reduction cells) is reviewed.
Modifications to conventional stationary combustion
sources considered include: ash fluxing, sulfur trioxide
addition to flue gas, staged combustion, the use of fuel
additives, fly ash agglomeration, solvent refining, and
flue gas recirculation. Unconventional systems studied
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52.
include: fluidized beds, coal gasification, and submerged
combustion. Combined flue-refuse firing, gas cooling, and
pyrolysis methods are considered for incinerators.
Emphasis for iron and steel plants is given to the
bottom-blowing oxygen process. Modification of the
conventional reverberatory smelting procedure and the
introduction of hydrometallurgical methods are discussed
for copper. The chloride electrolytic process by the
Aluminum Company of America is considered with respect to
its stage of development, availability or acceptability by
industry, efficiency in reducing emissions, and environ-
mental impact.
Oglesby, S., Jr., Nichols, G.B., "Electrical Resistivity and
Conditioning (Chapter 7)", Electrostatic Precipitation, Marcel
Dekker, Inc., New York, 1978.
Abstract;
Electrical resistivity of the dust influences electro-
static precipitators (ESP's). If the dust has high
resistivity in a single stage precipitator, the corona
current will be limited, reducing precipitator perform-
ance. The force holding the dust layer to the collecting
plant can be large with high resistivity dust, and high
intensity rapping is required. Such conditions can result
in larger than normal reentrainment. High electrical
resistivity of the dust can result in sparkover or back
corona. Increased thickness of the dust layer can cause a
change from a back corona to a sparking condition for the
same dust. The variations in current are such that the
maximum allowable current is lower by about a factor of
ten than predicted from theoretical considerations.
Volume resistivity and temperature are inversely related
at high temperatures. Surface conduction, occurring at
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lower temperatures, depends upon gaseous reaction with the
particles and the composition and morphology of the
particles. Conduction above about 250°C is controlled, by
an ionic mechanism and related to the alkali metals in the
ash. Surface resistivity is governed principally by the
potassium or sodium and lithium ion concentration.
Empirical relationships are given for determining the
surface resistivity of ashes. Hot precipitators operate
at 600-800°F, where the resistivity is usually low enough
that precipitator electrical conditions are not severely
limited by breakdown of the dust layer. However, about '
50% greater gas volume must be handled. Dust resistivity
can be altered changing the ash or flue gas composition.
Moisture conditioning, sulfur trioxide conditioning,
ammonia additions, and other conditioning agents are
discussed.
53. Ostrovski, O.P., Y.I. Chander, Y.N. Reznikov, L.N. Gulaga,
V.V. Martynenko, A.N. Timofeev, E.P. Mezentsev, I.P. Shkinder,
"Flue Gas Dust Recovery In Electrostatic Precipitators Improved
With An Additive To The Fuel Oil", Refractories Vol. 18, No.
1-2, January-February 1977.
Abstract;
When rotary kilns are fired with sulfurous fuel oil, the
electrostatic precipitators do not function efficiently
owing to the formation of a solid layer of dust on the
electrodes. As a result of high resitivity, the layer of
magnesite and dolomite dust on the precipitation
electrodes acts as an insulator so that the current
decreases sharply and an "inverse corona" is formed. The
formation of solid deposits is attributable to the
sulfurous and chlorous compounds in the material being
fired. An effective method of reducing dust deposits and
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increasing the efficiency of the dust extraction process
consists of using the fuel additive VNIINP-106.
54. Patterson, R., Riersgard, R., Parker R., Sparks, L.E., "Flue
Gas Conditioning Effects on Electrostatic Precipitators",
Symposium on the Transfer and Utilization of Particulate
Control Technology, EPA-600/7-79-044a, February 1979.
Abstract:
Flue gas conditioning agents are used primarily for
maintaining high particulate collection efficiency in
electrostatic precipitators operating on high resistivity
fly ash from low sulfur coals. Burning low sulfur coals
has been a popular method for meeting sulfur dioxide
emissions limits. Flue gas conditioning is rarely
designed into a new installation; rather, it is normally
used as a corrective method for an ailing precipitator.
Many conditioning agents have been investigated for
improving the collection efficiency of ESP's. When
injected, the conditioning agents mix with the gas to form
various gaseous and particulate compounds, depending on
the flue gas composition and temperature. This program is
designed to determine the improvement in ESP performance
and the additional gaseous and particulate compounds which
penetrate the ESP.
55. Paulson, C.A., Potter, E.G., Kahanne, R., "New Ideas on Precip-
itation Technology from the Csiro Combustion Rig", Presented at
the Changing Technology of Electrostatic Precipitation
Symposium, 1974.
Abstract:
A pilot scale coal burning electrostatic precipitation rig
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56.
is described and its use for assessing the precipitation
behavior of fly ash is explained. A method of plotting
dust collection efficiencies against a combined function
of specific collection area and applied voltage has been
developed, which yields a performance line for the
precipitator handling a given dust under stated conditions
of temperature and carrier gas composition. The
performance lines permit the comparison of the
precipitation behavior of fly ashes from different coals,
and are useful in assessing flue gas additives and in
estimating the design size of full scale precipitators
from pilot plant observations. The additives investigated
include ammonia, sulfur trioxide, trimethylamine,
triethylamine, and cyclohexylamine. The performance lines
show that triethylamine at trace levels improves
precipitator performance dramatically with difficult fly
ashes, the improvement being due to agglomeration of
suspended dust and raising of breakdown voltage. Some
other additives, particularly cyclohexylamine, worsen
precipitator performance by lowering breakdown voltage and
dispersive natural dust agglomerates.
Petersen, H.H., "Conditioning of Dust with Water-Soluble Alkali
Compounds", Symposium on the Transfer and Utilization of Parti-
culate Control Technology, EPA-600/7-79-044a, February 1979.
Abstract:
_
A comparison of resistivity measurements and chemical
analyses of dusts from cement rotary kilns has shown a
close relationship between resistivity and the content of
water-soluble alkali compounds. Laboratory experiments
comprising impregnation of high resistivity dust samples
with various water-soluble alkali salts confirmed that
small quantities of alkali compounds were sufficient to
reduce the resistivity considerably. This led to full
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scale experiments at a precipitator installation treating
high resistivity dust from a preheater kiln at a cement
plant in Brazil. Here an aqueous solution of potassium
sulfate was injected, atomized and evaporated in the gas
stream before the precipitator. An 0.4% increase in water
soluble K20 reduced the resistivity of the dust from 1013
to 1011 ohm-cm and a corresponding improvement in precip-
itator performance was observed. Recent additional full
scale conditioning experiments with potassium sulfate and
sodium chloride at a precipitator installation after a
coal-fired lime kiln in South Africa yield similar
results.
57. Radway, J.E., "Effectiveness of Fireside Additives in Coal-
Fired Boilers", Power Engineering, April 1978.
Abstract:
Benefits of using fireside additives in coal-fired boilers
are discussed. A case history is also presented. In
addition to aiding emission control and providing for
greater flexibility in coal use, chemical treatment may
improve operating reliability and increase boiler avail-
ability.
58. Roehr, J.D., "Flue Gas Conditioning Cold and Hot Precipit-
ators", Presented at the Southeastern Electric Exchange
Meeting, New Orleans, Louisiana, April 16-18, 1980.
Abstract:
This paper discusses the reasons for using flue gas con-
ditioning, the various methods and agents used and the
expected operating costs. Several agents or chemicals
have been used to achieve conditioning, such as ammonia,
water, sodium, sulfuric acid, etc. Proprietary compounds
are on the market and are also being used. Some of these
conditioning alternatives are outlined here.
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59
Schwarz, R.C., "Superior Fuel Oil Additives Carry Good
Engineering Credentials", National Engineering, Vol. 76, No. 8,
August 1972.
Abstract;
The choice of a proper fuel oil additive for the particu-
lar problems that beset an individual boiler is a diffi-
cult task. Before making a choice, one should know what
types of additives are available, what mechanism each uses
to function, and possible environmental complications that
can result from the use of each. The many additives on
the. market fall into four general groups: deposition con-
trol agents, combustion catalysts, sludge solubilizers,
and water emulsifiers. Each of these functions is dis-
cussed. Various metal compounds in fuel oil additives
include aluminum, barium, copper, lead, magnesium, and
manganese. Points worth serious consideration in evalu-
ating an additive supplier are listed. The condensation
of sulfur trioxide can cause fouling of the heat recovery
elements by a boiler system. Additives can reduce sulfur
dioxide coversion to 503. Combustion reduce carbon
particulates such as ash in flue gas. •
60. Selle, S.J., Hess, L.L., Sondreal, E.A., "Western Fly Ash
Composition as an Indicator of Resistivity and Pilot ESP
Removal Efficiency", Presented at the Air Pollution Control
Association, Annual Meeting, 68th, Boston, MA, June 15-20,
1975, Paper 75-02.5.
Abstract:
_
Pilot-scale electrostatic precipitator performance tests
were run on -a high and low resistivity western fly ash and
mixtures thereof. The fly ashes were collected from
full-scale electrostatic precipitator hoppers and re-
entrained in a flue gas of constant analysis ahead of a
120 scf/min pilot precipitator. Fly ash composition and
measured resistivity were good indicators of precipitator
performance. '
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Reentrained high sodium fly ash acted as an electrostatic
precipitator conditioning agent for high resistivity fly
ash.
The addition of only 0.75% of the high sodium fly ash
increased the effective migration velocity from 0.5 to 0.8
ft/sec at 300°F. Similar results were obtained at 475°F.
Computer regression analysis correlating laboratory fly
ash resistivity with chemical analysis substantiated the
inverse relationship between resistivity and sodium oxide
content of the fly ash.
61. Spafford, R.B., Dismukes, E.B., Dillon, H.K., "Analysis of
Thermal Decomposition Products of Flue Gas Conditioning
Agents", EPA/600/7-79-179, August 1979.
Abstract:
The report gives results of a study of reactions of sever-
al flue gas conditioning agents in a laboratory-scale
facility simulating conditions in the flue gas train of a
coal-burning power plant. Primary purposes of the study
•were to characterize the chemical species resulting from
adding conditioning agents to flue gas and to identify
potentially hazardous chemical species originating from
the agents that may be emitted into the environment. The
compounds investigated were sulfur trioxide, ammonia,
triethylamine, sodium carbonate, ammonium sulfate, and
diammonium hydrogen phosphate. The predominant types of
reactions observed in these experiments were thermal
decomposition fragments at lower temperatures, and react-
ions with normal components of the flue gas. The only
significant environmental threat of any product identified
during this stiady was the formation of N-nitrosodiethyla-
mine as the result of injecting triethylamine into the
flue gas. This potent carcinogen was found in trace
amounts when triethylamine was injected at 160°C.
62. Sparks, L.E., "Electrostatic Precipitators Options for
Collection of High Resistivity Fly Ash", Conference on
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Particulate Collection Problems in Converting to Low Sulfur
Coals, EPA-600/7-76-016, October 1976.
Abstract:
63.
An analysis of the technical options for collecting high
resistivity fly ash is presented. The options are a large
specific collection area at low temperatures (about
1500C), a wet electrostatic precipitator, a moderate to
large specific collection area electrostatic precipitator
operating at either high (about 370°c) or low temperature
(about 110°C), or a moderate specific collection area for
an electrostatic precipitator operating at normal
temperature with fly ash conditioning. The advantages and
disadvantages of each option are discussed. The potential
for adverse environmental impact of the conditioning
option is also discussed.
Steelhammer, J.C., Polizzotti, D.M., Graffeo, A.J., "Electro-
static Precipitators: Gas Conditioning", AICHE Symposium
Series, Series 74, Issue 175, 1978.
Abstract:
Unavailable
64.
Steelhammer, J.C., Nogash, D.R., Mangravite, F.J., Graffeo,
A.J., Terry, J.P., Harpel, W.L., "Effect of Chemical Additives
on Electrostatic Precipitator Performance", Presented at the
Purdue Air Quality Conference, Annual, 14th, November 12-13,
1975.
Abstract;
Field evaluations of the effect of. various chemical
additives on electrostatic precipitator performance were
performed. The coal used throughout the experiments
contained between 2 and 3% sulfur, 20-25% ash, and 5-7%
mixture. The chemical additives were fed to the flue gas
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65.
as aqueous solutions, and the chemical feed system
consisted of several air atomizing spray nozzles. The
chemical additives were fed to the flue gas for
approximately 1-3 hours before particulate sampling was
started. Increases in precipitator collection efficiency
were obtained with one organic and two inorganic
additives. Efficiencies of 96.4%, 95.3%, and 94,9%,
respectively, were obtained with the additives as compared
to a control efficiency of 91.9%. The increased
efficiencies appeared to be due to space charge effects
and cohesivity modification.
Technology Update, "Fuel Additives: The Bottom Line for Energy
Savings and Pollution Control", Plant Energy Management, March/
April 1978.
Abstract;
Because of rising fuel costs, many industrial plants are
converting to cheaper, less desirable fuel. This
conversion can create problems unless these fuels are
somehow treated. This paper shows how fuel additives can
be used to solve the problems of slag, corrosion, and air
pollution control.
66. Troupe, J.S., "Handwriting on the Power Plant Wall-Flue Gas
Treatment", Combustion, Vol. 50, No. 4, October 1978.
Abstract:
The more important points of flue gas treatment technology
are addressed. Control of particulate matter and sulfur
dioxide is discussed. The capital cost of flue gas
cleaning may be about 20% of the cost of the entire power
plant. SO2 control can account for 65-75%.
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67.
Tseluiko, Yu. I., Chander, Yu. I., Borisovskii, L.M., "Ammonia
Added to the Gas-and-Dust Emission of Rotary Kilns as a Factor
in the Performance of the Electrical Precipitators",
Refractories, Vol. 16, No. 11-12, November-December 1975.
Abstract:
68.
Electrical precipitators are the most efficient gas
scrubbers used in the refractories industry. The degree
of dust entrapment by these devices depends on their
design and electrical regime and on the properties of the
gas and dust mixture emitted by the kiln. The
.resistivity, i.e., specific electrical resistance (SER),
of the dust is a significant factor in the performance of
the precipitator. Conditioning the flue gas with ammonia
reduces the SER of the dust so that the degree of.
dust entrapment in electrical•precipitators increases,
especially when the flue gas contains a large proportion
of sulfur oxides. Conditioning is at optimum with a 3-6%
ammonia solution and an ammonia consumption of 4-5 kg per
100,000 m3 flue gas.
Walker, A.B., "Characteristics and Electrostatic Collection of
Particulate Emissions from Combustion of Low Sulfur Western
Coals", Presented at the Air Pollution Control Asociation,
Annual Meeting, 67th, Denver, CO, June 9-13, 1974, Paper 74-11.
Abstract:
About 90% of the known strippable low-sulfur coal reserves
in the U.S. are in the area west of the Mississippi
River. These coals can meet sulfur oxide emission
regulations without the need for flue gas desulfur-
ization. The principal use of these coals will be as fuel
for conventional boilers which will require particulate
removal efficiencies in excess of 99%. The
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69.
emission characteristics and electrostatic pfecipitator
performance tests on these coals are desribed. Mass
emissions as a percentage of fuel ash were somewhat lower
than Eastern bituminous coals, but there was insufficient
information to suggest deviation from currently available
methods, based upon Eastern coals, for predicting ash
carryover. Size distribution of particulate emissions on
pulverized coal units was similar to that of Eastern
bituminous coal. However, size distribution of
particulates from Western coals in cyclone boilers was
somewhat coarser that from the same fuel in pulverized
coal units or predicted from available data on Eastern
bituminous coals burned in cyclone boilers. Bulk
electrical resitivity of Western fuel ash at typical air
heater outlet temperatures varied over a wide range, could
not be predicted on the basis of fuel sulfur alone, and
generally was above the level where back corona would be
expected. The bulk electrical resistivity of Western fuel
ash, at typical air heater inlet temperatures, varied over
a narrower range with most of the cases encountered being
below the level where back corona would be expected.
Precipitator performance can generally be correlated
according to a modified form of the Deutsch equation.
This indicates that specific collecting electrode areas in
the range of 350-550 sq ft/1000 acfm are required for
achievement of 99% collection efficiency on fly ash with
in-situ resistivity levels in the range of I0l°-1012
ohm-cm; and that specific collecting areas as high as
900-1000 sq ft/1000 acfm may be required to achieve
efficiencies in the 99.8% range.
Watson, K.S., "Australian Experience with Flue Gas
Conditioning", Particulate Control in Energy Processes, EPA
600/7-76-010, September 1976.
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Abstract;
Australian black coal fired in power stations usually
contain less than 1% sulfur and has 15 to 30% ash. Target
emission levels for new plants are often better than 0.1
gm/m3 at NTP -requiring collection efficiencies of 99.5%.
Highly resistive fly ash predicates specific collecting
areas in excess of 80 m2/m3/s (400 ft2/1000 cfm) for cold
precipitators. Early precipitators frequently had
specific collecting areas of less that 50 m2/m3/s and
performed badly. Gas conditioning has been regularly used
to improve collection efficiencies since the middle 60'a
and to date has been provided on 26 precipitators on
boilers from 25 to 500 MW capacity and totalling over
4,000 MW.
Steam and/or water temperature modification, P2O5, NH3,
and S03 were used experimentally from 1955 onwards.
Sulfuric acid was first used operationally in 1964 and
anhydrous ammonia has been used since 1965. Triethylamine
was first used in 1975 and is currently being evaluated.
The effect of reagents varies from station to station and
is also dependent on precipitator type and reagent con-
centration. Considerable care must be given to the
injection system to allow proper mixing and sufficient
resident time. Improvements of migration velocity in
excess of 300% have been attained with SO3/H2SO4 and in
excess of 200% with ammonia, which is perferred reagent
because of its relative safety and convenience. Triethy-
lamine appears to be even more effective than SO3.
Comparatively few operational problems have been reported
and most can be traced to over-conditioning or to poor
distribution. Capital costs range from 0.05 to 0.12 $/KW
and operating costs fom 0.01 to 0.05 mils/KW-hr depending
on the reagent and injection concentration.
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70. White, H.J., "Electrostatic Precipitation of Fly Ash, Fly Ash
and Furnance Gas Characteristics (Part II, Section 3)", J. Air
Pollution Control Association, Vol. 27, No. 2, February 1977.
Abstracts:
Fly ash and furnace ,.gas characteristics that affect design
and performance of electrostatic precipitators are
discussed. The composition, temperature, and pressure
of
the basic corona characteristics of the
the gas govern
precipitator, while particle size, particle concentration,
and electrical resistivity of the fly ash affect both the
corona and the particle collection properties. The gas
flow volume rate is also fundamental to precipitator
design and performance. The chemical compositions of
different kinds of coal and of typical furnace gases are
present in the precipitator. The presence of sulfur
trioxide (SO3) in the flue gas greatly reduces the
electrical resistivity of the fly ash, by raising the
dewpoint of the flue gas. Problems with high resistivity
can
is of
be caused by the use of low sulfur coals; responses
include the location of precipitators ahead of, rather
than after, the air preheater, where gas temperature
600 to 800°F are sufficiently high to overcome problems of
high resistivity. The chemical analysis of fly ash is
presented from the literature. Particle size
distributions of ash from power plants are given. The
measurement and significance of particle size and the
resistivity of fly ash are discussed.
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2.2 Specific Methods and Agents
Several chemicals have been successfully used on coal-fired
utilities to improve the collection efficiency of electrostatic
precipitators. There are about five major suppliers of FGC
systems in the U.S.A. In most of the cases, the conditioning
agent is injected into the flue gas in the form of a liquid
spray, often between the air preheater and the ESP. Sometimes,
it is injected in the furnace. Sulfur trioxide, sulfuric acid,
ammonia, sodium and ammonium compounds are some of.the commonly
used conditioning agents. In addition, there are many
proprietary chemicals whose compositions are kept confidential.
The literature cited in this section deals with the use and
effects of the specific agents. Many references give
information on the particulate emissions before and after
conditioning. Limitations to the use of specific agents and
some common difficulties are also discussed.
1. Archer, William E. , "Flyash Conditioning Update", Power Eng.,
Vol. 81, No. 6, June 1977.
2.
Abstract;
An account is given of the use of flue gas conditioning by
injecting trace amounts of SO3 into the flue gas stream
ahead of the electrostatic precipitator in order to reduce
the resistivity of the flyash to a level at which the
precipitator can function normally.
Atkins, Richard S., and David H. Klipstein, "Improved
Precipitator Performance by SO3 Gas Conditioning", Natl. Eng.,
Vol. 79, No. 11, Nov. 1975.
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Abstract;
Gas conditioning can dramatically improve the performance
of electrostatic precipitators at relatively low cost. It
can be applied to precipitators already in operation and
to new units. It involves injecting small quantities of a
chemical into the flue gas which optimizes the electrical
resistivity of fly ash, making it more amenable to
collection in a precipitator. Precipitator performance is
discussed. Dust conductivity may be increased by small
quantities of easily ionized chemicals called conditioning
agents. Typically, conditioning compounds for each type
of dust are found by educated trial and error. The most
common conditioning agents are sulfuric acid and ammonia.
There are several types of commercial sulfur trioxide gas
conditioning systems: evaporation of liquid SOj;-
catalytic conversion of sulfur dioxide; vaporization of
sulfuric acid; and sulfur burning followed by the
catalytic conversion of SO2 to SO3. The simplest is a
liquid SO3 gas conditioning system. Sulfuric acid is
heated above its boiling point, vaporized, and diluted
with air in acid vaporization. Then it is injected into
the flue ahead of the precipitator. About 70 to 75% of
SO2 can be converted to SO3 by catalytic conversion. The
resultant mixture will then be injected into the flue
gas. Sulfur burning is also described. In situ, portable
test, mobile, and computer equipment is discussed. When
switching to a lower sulfur fuel, existing precipitators
are unlikely to" maintain performance without either
increased precipitator capacity,'reduction in boiler
operating rate, or gas conditioning.
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3.
Baxter, Walter A., "Recent Electrostatic Precipitator
Experience with Ammonia Conditioning of Power Boiler Flue
Gases", Journal of the APCA, Vol. 18, No. 12, December 1968
Abstract:
This paper discusses experiments done by Koppers Company
with ammonia conditioning of power boiler flue gases for
the purpose of improving the precipitability of the
emitted fly ash. Chemical reactions resulting from
ammonia injection are postulated. Measurements on three
pulverized coal and two cyclone fired boilers, all of
which emit acidic ash, are described. in all five cases,
considerable but varying, increase in precipitator power'
input and collection efficiency resulted when gaseous
ammonia in the amount of 15 ppm was injected between the
economizer and air preheater. The conditioned fly ash
showed decreased acidity and inconsistent change in
electrical resistivity. Unless air heater temperatures
were unusually high (>400°F), the tendency of the air
heater to plug was an additional, but unwanted, result.
At one station with high air heater outlet temperatures,
ammonia injection has been adopted as a permanent solution
to community pressure for reduction of stack discharge.
Ammonia injection downstream of the air heater produced no
effect. Future plans are presented to continue the
program beyond results described here.
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Bennett, R.P., "Fly Ash Conditioning to Improve Precipitator
Efficiency with Low Sulfur Coals", ASME Publication
76-WA/APC-8, December 1976.
Abstract; (
The use of blended'chemical agents to condition coal fly
ash to improve electrostatic precipitator efficiency and
reduce particulate emissions has been subjected to
extensive field trials to verify its broad application as
a possible economic solution to pollution problems for the
electric utility industry. These chemical conditioning
agents have been used with a variety of low to medium
sulfur coals resulting in precipitator efficiency
improvements of 50 to 90 percent. Emissions compliance
levels are often obtained as a result of this treatment.
The effectiveness of this system has been demonstrated on
units from 25 to 750 MW. Case history examples illustrate
the types of units treated and the extent of emissions
reductions obtained.
Bennett, R.P., Kober A.E., "Chemical Enhancement of
Electrostatic Precipitator Efficiency", Symposium on the
Transfer and Utilization of Particulate Control Technology,
EPA-600/7-790044a, February 1979.
Abstract:
It has been shown previously that chemical conditioning of
flyash can offer an immediately available alternative to
retrofit precipitators, baghouses, "or other methods of
mechanical collection and usually provides compliance
emissions at relatively low operating costs. The
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6.
operating equipment required involves minimum capital
investment and can usually be installed in a matter of
weeks with no significant unit downtime being involved.
It has now been demonstrated that the technique of
chemical conditioning can be expanded into a previously
untried area with the successful treatment of high-sulfur
coals, of hot precipitators, and of low-sulfur coals
utilizing a dual-injection system to provide minimum
emissions and minimum opacity. Ready availability and
minimum total costs are two advantages of this method.
The use of new conditioning agents for these processes is
continually being examined for further advances in the
state of flue gas chemical conditioning.
Bickelhaupt, R.E., "Sodium Conditioning to Reduce Fly'Ash Re-
sistivity", EPA/650/2-74-092, October 1974.
Abstracts
The resistivity of fly ash is often too high under a
particular set of operating conditions to permit the most
efficient use of an electrostatic precipitator. A variety
of substances, generally referred to as conditioning
agents, can be added to the boiler or to the effluent gas
downstream to attenuate the high resistivity. The report
gives results of a review of recent research, including
the result of two field tests of sodium conditioning, on
the effects of sodium content on the electrical
resistivity of coal fly ash. it presents a procedure for
calculating .the amount of sodium that must be added to
reduce fly ash electrical resistivity to a desired value.
It discusses advantages and disadvantages of sodium
conditioning for reducing fly ash resistivity.
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7. Bickelhaupt, R.E., Dismukes, E.B., Spafford, R.B., "Flue Gas
Conditioning for Enhanced Precipitation of Difficult Ashes,
Final Report", EPRI-FP-910, October 1978.
Abstract;
A review of the available prior investigations indicates
that the effectiveness of ammonia and triethylamine as
conditioning agents used to improve the performance of
electrostatic precipitators has been inconclusive. When
successful conditioning has occurred, it sometimes has
been impossible to determine the process by which the
conditioning agent affects the performance. The objective
of this research was to examine the ability of these two
conditioning agents with respect to the attenuation of
resistivity and the suppression of back corona.
Conventional resistivity determinations were made using
simulated flue gas environments containing the subject
agents. A second approach utilized a wire-guarded plate
apparatus for the determination of voltage-current
relationships. With regard to the effect these
conditioning agents have on the electrical characteristics
of a precipitator, the laboratory data suggest only an
attenuation of resistivity. A mechanism by which these
agents enhance conduction is hypothesized. The usefulness
of triethylamine and particulary ammonia is severely
limited by temperature and ash composition. The
effectiveness of both agents is also influenced by the
sulfur oxides present. The voltage-current data suffered
from several experimental difficulties. In general, the
data support the observation that these agents are capable
of reducing resistivity under certain limiting
conditions. Experimental problems prevented the
observation of space charge effects related to ammonia
injection that have been identified during field testing
performed by one of the authors and reported elsewhere.
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8.
Borsheim, R., "Flyash Conditioning Brings Particulate Emissions
Into Compliance", Power Eng., Vol. 81, No. 1, January 1977.
Abstract:
Low sulfur coal has unfavorable consequences on the
performance of an electrostatic precipitator. Electrical
resistivity of the fly ash, fly ash particle size
distribution, and space charge affect the performance of
the electrostatic precipitator in a coal burning power
plant. Fly ash conditioning involves injecting an agent
into the flue gas, making the fly ash more collectible by
the electrostatic precipitator. One commercial additive
lowers the electrical resistivity of the fly ash by
adsorbing some conductive species on the surface of the
particles. When the Corette Power Station started burning
coal containing 0.7 to 0.9% sulfur and 8 to 10% ash, the
electrostatic precipitator performance was insufficient to
meet particulate emission standards at all loads, and the
unit was operated up to 16% below its load rating in order
to comply. Mechanical and electrical improvements
increased efficiency somewhat, but did not permit
full-power operation. Opacity was measured constantly.
Pre-trial testing in the 148 to 150 MW range gave opacity
readings between 30 and 40%. Opacity levels dropped to 15
to 18% within 4 hr after the start of treatment. The
amount of generation lost by derating was extremely high.
Chemical treatment allowed boiler operating loads to be
raised from an average of 148 MW to full load without
exceeding particulate emissions and plume opacity limits.
The cooling system used prior to treatment deprived the"
unit of combustion air. Cooling is not longer necessary
to maximize precipitator performance. Cost of the
treatment is less than 40 cent/ton of coal. This
technology makes possible high collection efficiencies on
existing equipment at modest prices.
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9. Breich, E.W., "Flue Gas Conditioning for New Electrostatic
Precipitators/An Economic Evaluation", Presented at the
Symposium on the Transfer and Utilization of Particulate
Control Technology, University of Denver, Denver, CO, July
24-28, 1978.
Abstract;
This paper discusses the methods and associated costs of
alternative collectors for the collection of low sulfur
coal fly ash on an 800 MW unit. Systems evaluated
include: cold side precipitators, hot side precipitators,
cold side precipitator with Flue Gas Conditioning, fabric
filters, and flue gas desulfurization systems (scrubbers).
In the case of the scrubber, it is assumed that the fly
ash is removed by either a precipitator system or fabric
filter before entry into the scrubber for removal of
sulfur oxides.
10. Breisch, E.W., "Method and Cost Analysis of Alternative
Collectors for Low Sulfur Coal Fly Ash", Symposium on the
Transfer and Utilization of Particulate Control Technology,
EPA-600/7-79-044a, February 1979.
Abstract;
Flue gas conditioning in conjunction with a conventionally
sized precipitator is shown to be the most cost-effective
means of collecting low sulfur coal, high resistivity fly
ash. The results obtained with flue .gas conditioning are
both predictable and dramatic.
A case in point is the experience which Public Service
Company of Colorado has had with vendors for their new
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99.2% efficient precipitator installation at Arapahoe
Station Unit 1. PSCC received bids from a number of
vendors for hot side precipitators and for cold side
precipitators with and without conditioning. The Specific
Collecting Areas proposed ranged from 295 to 334.5 for the
hot gas side precipitator. The bids for cold side ranged
from an SCA of 688 with no conditioning, down to 279 with
conditioning. PSCC chose the conditioned precipitator and
after a year's operation of the combined installation,
acceptance tests were conducted. The results were even
better than the original conformance tests. Emissions In
Ib/MM BTU's were 0.0161; well below the statutory limit of
0.10. Average outlet grain loadings were only 0.0079
gr/dscf.
11. Brines, E.G., Reveley, R.L., "Flue Gas Conditioning To Reduce
Size and Costs of a New Precipitator at PSCC Arapahoe Station
Unit No. 1", Proc. Am. Power Conf., Vol. 40, Chicago, IL, April
24-26, 1978, Sponsored by 111. inst. of Technol. Chicago, 1978.
Abstract:
This paper is a case history of the design and selection
of a new cold-side electrostatic precipitator install-
ation, working with a flue gas conditioning system at the
Arapahoe Station Unit 1, Public Service Company of
Colorado (PSCC). The installation is guaranteed to meet
particulate emission regulations and performance criteria
of the design specifications for a particulate control
device. Unit No. 1 at Arapahoe is a steam/electric gener-
ating unit rated at 44,000 KW. It has a Babcock & Wilcox
steam generator and ball mills and was designed to burn
coal or gas. The generating unit was installed in 1950.
Until the precipitator was installed, it was equipped with
only a mechanical dust collector.
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12. Brown, T.D., Lee, G.K., Reeve, J., Sekhar, N., "Improved
Electrostatic Performance by Use of Flyash Conditioning
Agents", Journal of the Institute of Fuel, Series 51, Issue
409, 1978.
Abstract;
Unavailable
13. Cheremisinoff, P.N., "Advanced Flyash Conditioning Technology",
Power Engineering, November 1977.
14.
Abstract;
Effects of high resistivity flyash on the precipitator
performance are discussed. Improvements in precipitator
performance can be accomplished by new conditioning agents
which not only control the conductivity of flyash but also
increase the particle-to-particle cohesion and the space
charge.
Cohen, Murray S., Bennett, R.P.V "Case Studies on Chemical Flue
Gas Treatment As A Means of Meeting Particulate Emission
Regulations", ACS Symposium Ser., No. 109, Miami Beach, FL,
September 14, 1978.
Abstract;
A description is given of the chronological development of
two streams of Federal legislation, one regulating the
emissions of particulates from large stationary sources
and the other seeking to reduce the dependence upon
foreign oil imports. It shows how these regulations
offered an opportunity for the development and
commercialization of a new technology called chemical flue
gas conditioning. An explanation is given of the
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15.
operation of existing particulate control device,. notably
the electrostatic precipitator (ESP,. fl ascription is
also given of how particulate capturability can be
improved by chemical treatment and then how a proprietary
Ration has lead to the treatment of a wide variety L
fuels ln both cold and hot side ESP units is illustrated.
Evidence is also presented showing that fine particular
emissions, i.e., those indicated in health effects, could
be significantly reduced.
Cragle, S.H., "Operating Experience with ESP Conditioning m
Elation to an Electrostatic Precipitator Opgradin P g a".
Conference on Particulate Collection Problems in Converting o
Low sulfur coals, EPA-600/7-76-016, October 1976.
Abstract;
This report summarises the major areas of an ongoing
electrostatic preeipitator (ESP) upgrading program at
Pennsylvania Power and Light Company. Particular emphasis
is placed on the area of flue gas conditioning including
eighteen months of operating experience with Apollo
Chemical Corporation products, a planned SO3 injection
trial, and other potential agents.
.Results of ongoing trials of Apollo products at Montour
SES on two 750 MW bituminous coal fired units are
Presented. Performance data, operating problems and cost
information are covered. Eight chemical formulations have
been injected into various combinations of four Xocations
in efforts to improve product performance, solve air
heater plugging problems, and improve distribution of the
product on the fly ash. A significant reduction of
emissions on a difficult- fi^ =~-u -u -L.
itficult fly ash has been noted although
only half as great a reduction as originally expected
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based on tests run with a good collecting fly ash,
heater plugging problems have been eliminated.
Air
The report also covers some of the practical
considerations and potential problems that can occur in
evaluating proprietary additives.
Also, the report briefly summarizes projects on six of the
Company's ESP's including work in the following areas:
fuel quality effects; flue gas conditioning; rappers;
voltage controls; sectionalizing; gas flow distribution;
operation and maintenance; and additional dust collector
capacity.
16. Cook, R., Trykoski, M., "Sulfur Trioxide Injection at State
Line Station", EPA-600/7-76-016, October 1976.
Abstract:
Commonwealth Edison's efforts to overcome the problem of
electrostatic precipitator degradation through the use of
sulfur trioxide (SO3) flue gas conditioning is described.
An analysis of the coal (low sulfur) being burned in
Edison boilers revealed that the coal fly ash, with its
higher resistivity, reduces the current flow between the
electrodes of the electrostatic precipitator, and
therefore the precipitator performance is reduced when
compared to operation on high-sulfur coal. Evaluation of
the Edison generating system showed that a total of 22
precipitators on ten generating units ranging in size from
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120 to 620 MW would suffer degradation while burning low
sulfur coal to the point where they could no longer meet
particulate emission standards while operating at full
load. Flue gas conditioning was sought as a means of
restoring precipitator efficiency through the lowering of
fly ash resistivity. Test results showed a dramatic
improvement in precipitator performance with flue gas
conditioning. Problems related to startup and
miscellaneous boiler and precipitator effects are noted.
Flue gas conditioning systems have not alleviated the
other operating problems associated with the burning of ;
low sulfur coal, but they are enabling these units to meet
particulate emission standards with minimal derating at a
cost far less than that of the only other feasible
alternatives, major precipitator rebuild or a new
precipitator.
17. Cook, Jl.E., "Sulfur Trioxide Conditioning", J. Air Pollution
Control Association, Vol. 25, No. 2, February 1975.
Abstract:
Burning of western low sulfur coal, to reduce sulfur oxide
emissions, has resulted in decreased electrostatic
precipitator collection efficiencies. In an effort to
restore precipitator performance a flue gas conditioning
program was established. This paper discusses experience
with sulfur trioxide as a flue gas conditioning agent.
Testing at State Line Station has proven that sulfur
trioxide conditioning can effectively be used to improve
precipitator performance when burning low sulfur coals.
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18. Dismukes, E.B., "A Study of Resistivity and Conditioning of Fly
Ash", EPA-R2-72-087, February 1972.
Abstract:
19.
An experimental study was made on the injection of SO3 and
H2SO4 gaseous' conditioning agents to alleviate the problem
of high electrical resistivity of fly ash.
Dismukes, E.B., "Conditioning of Fly Ash with Sulfamic Acid,
Ammonium Sulfate and Ammonium Bisulfate", EPA/650/2—74-114,
October 1974.
Abstract;
The report summarizes recent experience with three
agents—sulfamic acid, ammonium sulfate, and ammonium
bisulfate—used to regulate the electrical resistivity of
fly ash in electric generating stations to ensure ;
satisfactory collection of fly ash in electrostatic
precipitator (ESP's). It presents information about the
effectiveness of these agents in pilot- and full-scale
ESP's.' It also presents the limited information available
from practical trials of these agents concerning their
conditioning mechanisms. It discusses in detail the
fundamental physical and chemical properties of the agents
that are relevant to fly-ash conditioning. From this
information and the results of ESP tests, the report
offers tentative conclusions about conditioning
mechanisms. Finally, the report briefly discusses the
economic aspects of using each of the-agents as a
conditioning substitute for sulfur trioxide.
-------
20. Dismukes, E.B., "Conditioning of Fly Ash With Ammonia", Journal
of the APCA, Vol. 25, No. 2, February 1975.
Abstract;
This paper presents the results of an investigation of the
conditioning of fly ash with ammonia in electrostatic
precipitators of power plants operated by the Tennessee
Valley Authority. It focuses attention primarily on the
mechanisms of conditioning encountered under the
particular circumstances available for study. No effect
of ammonia on the electrical resistivity of fly ash was
evident. Instead, the effect of ammonia appeared to be an
enhancement of the space-charge component of the electric
field used for charging and precipitating particles of fly
ash. In addition, a second effect appeared to be an
increase in the cohesiveness of precipitated ash and a
reduction in the quantity of ash reentrained during
electrode rapping. Data demonstrating the value of
ammonia conditioning for lowering the emission of fly ash
during three precipitator studies are presented. Reasons
for the ineffectiveness of ammonia conditioning during a
fourth precipitator study are discussed. In conclusion,
comments are made about the effects to be expected from
ammonia conditioning under circumstances different from
those investigated experimentally, particularly with
ammonia as a conditioning agent for fly ash from low
sulfur western coal.
21. Dismukes, E.B, "Conditioning of Fly Ash with Sulfamic Acid",
EPA-650/2-75-016, 1975.
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Abstract;
Pilot plant and field tests of sulfamic acid flue gas
conditioning for the reduction of fly ash resistivity and
increased electrostatic precipitator collection efficiency
are reviewed. Sulfamic acid appears to be a worthy sub-
stitute for sulfur trioxide as a flue gas conditioning
agent, as evidenced by increases in collection efficiency
obtained at various coal-burning plants with high-
resistivity fly ash problems. The primary advantages of
sulfamic acid are its ease of handling and freedom from
hazard; the high cost of the chemical is its main dis-
advantage. The mechanisms by which sulfamic acid acts as
a conditioning agent are not clearly established.
22. Dismukes, E.B., "Conditioning of Fly Ash with Sulfur Trioxide
and Ammonia", EPA-600/2-75-015, August 1975.
Abstract:
The use of sulfur trioxide and ammonia as flue gas con-
ditioners to improve the elctrostatic precipitation of fly
ash generated in coal-burning power plants was investi-
gated. The primary role of 503 in improving collection
appeared to be related to a lowering of fly ash resistiv-
ity from the excessive values associated with ash from
low-sulfur coals. Ammonia conditioning appeared to
involve a space charge of the precipitator as well as an
increase in the cohesiveness of the collected ash at
times. Satisfactory sites of injection were the flue gas
ducts in locations upstream from the precipitator, up-
stream from the combination of a precipitator and mechan-
ical collector, and between the two types of collectors.
Ply ash was successfully conditioned at temperatures
ranging from 110 to at least 160°C.
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23.
Dismukes, E.B., "Techniques for Conditioning Fly Ash", Confer-
ence on Participate Collection Problems in Converting to Low
Sulfur Coals, EPA 600/7-76-016, October 1976.
Abstract:
Conditioning of fly ash is discussed in connection with
electrostatic precipitators from several points .of view:
the purposes served, the types of chemicals used, and
their mechanisms of action. Major emphasis is given to
resistivity modification with sulfur trioxide and other
agents. Comments are also made on alternative
conditioning mechanisms, increasing the cohesiveness of
deposited fly ash to minimze reentrainment, and improving
the electrical properties to flue gas to increase the
efficiency of collection.
24. Dismukes, E.B., Gooch, J.P., "Fly Ash Conditioning With Sulfur
Trioxide", EPA/600/2-77/242, December 1977.
Abstract;
The report describes an evaluation of an SO3 injection
system for the George Neal Unit 2 boiler of the Iowa
Public Service Company in Sioux City, Iowa. Results of
base line tests without conditioning indicate a dust
resistivity of 6 x 10 to the 12th power ohm-cm at 118°C;
the precipitator's average collection efficiency was 91.3%
at a-specific collecting area of 42.8 sq m2/(m3/sec)>
Because transformer-rectifier sets tripped out, apparently
due to ash buildup in the hoppers, only one precipitator
efficiency test was conducted with SO3 system operating
continuously with all T-R sets operating. Results of this
test were: (1) specific collecting area =41.8 m2/(m3/
sec); (2) collection efficiencies = 99.27% (ASME method),
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98.96% (EPA method), and 98.78% (EPA method, including
first impinger residue); and (3) 4 x 10 to the 10th power
ohm-cm dust resistivity at 143°C. An adequate accounting
was made for the fate of the injected SO3.
25. Engel, W. and M. Meyerkord, "Flue Gas Conditioning at Wisconsin
Power & Light to Improve Hot-side Precipitator Performance",
Presented at the Seventh Annual Technical Conference of the Air
Pollution Control Association, Midwest Section, Kansas City,
Missouri, May 22-23, 1980.
Abstract;
To meet emission standards for sulfur dioxide, an increas-
ing number of power plants have turned to western low-
sulfur coal. While this has several technical and
economic advantages, the fly ash released upon burning
these coals is unfavorable in certain installations for
adequate collection by electrostatic precipitators
(ESPs). Reasons for this unfavorable performance have
been related to high electrical resistivity of fly ash and
relatively high proportion of small particle fly ash.
The cold side precipitator is still the most common means
of particulate collection, especially for plants construc-
ted before the early '70s. Hot-side precipitators are
designed to eliminate the problem of high fly ash resis-
tivity. The concept of the hot-side ESP was based on the
correlations observed between sulfur content in coal, flue
gas temperature, and fly ash resistivity. Fly ash resis-
tivity drops sharply at elevated temperatures. Placement
of the precipitator prior to the air heater where gas
temperatures are typically 600-800°F, helps to overcome
the resistivity problems. Many precipitators perform
adequately in this mode. Certain low-sulfur coals, how-
ever, continue to produce a fly ash chemistry detrimental
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to precipitator operation, despite the higher flue gas
temperature.
This phenomenon was experienced when Wisconsin Power &
Light Company's Columbia Station Unit #1 went on line in
the latter half of 1975. WP&L planners designed the unit
around utilization of low-sulfur western coal, selecting
hot-side electrostatic precipitation as the means of con-
trolling fly ash emissions.
Chemical flue gas conditioning, a technology that has been
effective in upgrading the efficiency of cold side .
electrostatic precipitators, has been successfully devel-
oped to overcome fly ash collection problems on hot side
ESPs. Known commercially as the Coaltrol HPC system, this
new flue gas conditioning system for hot-side precip-
itators has been applied at Columbia Station, enabling the
plant to continue to comply with opacity and emission
requirements.
26. Ferrigan, J.J., m, and J.D. Roehr, "SO3 Conditioning for
Improved Electrostatic Precipitator Performance Operating on
Low Sulfur Coal," Proceedings of the Symposium on the Transfer
and Utilization of Particulate Control Technology, Denver,
Colorado, 1979.
Abstract:
This presentation deals with a case study of a particular
utility's dilemna of having to choose an efficient and
reliable air pollution control device to lower stack
emissions on an existing unit. The paper traces the study
from the time when excessive emissions required MW load
deratings into the decision making process, the testing
stage, and finally into the installation of SO3 flue gas
conditioning.
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It points out why, in this particular case, 803 flue gas
conditioning is a more reasonable choice than the instal-
lation of a new cold side precipitator or fabric filter
baghouse. It clearly shows via test results supplied by a
utility based in upstate New York that 803 flue gas con-
ditioning enables units at their power plant to operate
well within the legal standards enforced by the New York
State Department of Environmental Conservation (NYSDEC).
27. Green, G.P., "Operating Experience with Particulate Control
Devices", Presented at the American Society of Mechanical
Engineers, Air Pollution Control Division, National Symposium,
3rd, Philadelphia, PA, April 1973.
28.
Abstract;
Operating experience associated with the control of
particulate emissions from steam plant units burning low
sulfur, high resistivity, western coals is reviewed.
Initially disappointing collection efficiencies with
electrostatic precipitators were improved by conditioning
the flue gas with sulfur trioxide such that its concent-
ration in the gas to be treated was 20 ppm. Collection
efficiencies for eight different units ranged from
37.5-94.0% before flue gas conditioning and from
51.2-97.2% after conditioning with SO3.
Green, G.P., Landers, W.S., "Operating Experience With Gas
Conditioned Electrostatic Precipitators", United States-USSR
Working Group, Stationary Source Air Pollution Control
Technology, Control Pine-Part., Emiss. Ihd. Sources Symposium
Proc., San Francisco, CA, 1974, January 15-18, Paper 8.
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Abstract:
29.
The effect of flue gas conditioning on the fly ash
collection efficiency of eight electrostatic precipitators
installed on pulverized coal burning units of the Public
Service Company of Colorado is reported. The addition of
15-20 ppm of sulfur trioxide directly to the flue gas
before the electrostatic precipitator increased collection
efficiencies from a range of 37.5-94.0% for the eight
units prior to gas conditioning to a range of 51.4-96.2%.
The low efficiencies prior to SO3 treatment were due to
the high resistivity of the untreated fly ash (10 to the
13 ohm-cm) which in turn was due to the fact that the
plant burns low sulfur western coal. Gas conditioning did
not compensate for design deficiencies other than the
resistivity problem.
Jaworowski, R.J., O'Connor, M.J., "Effect of Flue Gas Con-
ditioned Fly Ash on Electrostatic Precipitator Control", Pro-
curement of the ISA Conference and Exhibition, Philadelphia,
PA, October 15-19, 1978.
Abstract;
Electrostatic precipitators (ESP) are designed for a
specific combination of dust fineness, resistivity, and
concentration. The ability of the ESP to cope with
changes in these parameters is limited and significant
reductions in performance often accompany changes in coal
supplies (high sulfur coal to low sulfur coal to reduce
S02 emissions). This paper discusses the use of
precipitator control readings to diagnose problems
resulting from changes in fly ash resistivity, particle
size distribution, and concentration. The use of chemical
conditioning agents to overcome the adverse effects of
these changes is discussed and examples of successful
applications are given.
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30. Kanowski, S., Coughlin, R.W., "Catalytic Conditioning of Fly
Ash Without Addition of SO3 from External Sources", Environ-
mental Science Technology, Vol. 11, No. 1, January 1977.
Abstract:
Data and experimental results are presented to demonstrate
that catalytic oxidation of sulfur dioxide (SO2) at the
low concentrations normally present in flue gas from low
sulfur coal can produce sulfur trioxide SO3 in concent-
rations sufficiently large to cause good conditioning by
significantly lowering the resistivity of fly ash. This
was accomplished by disposing catalysts in streams of SO2
bearing flue gas and measuring the effects of the gases so
treated on the resistivity of carbon-free fly ash obtained
from several different coal-fired power stations.
Concentrations of SO2 and SO3 were measured by gas samp-
ling and chemical analysis. The effects of moisture and
temperature were also investigated.
31. Kropp, L.I., Shmigol, I.N., Chekanov, G.S., Oglesby, S.,
Bickelhaupt, R.E., "Joint US/USSR Test Program for Reducing Fly
Ash Resistivity", Journal of the APCA, Vol. 29, No. 6, June
1979.
Abstract;
An electrostatic precipitator preceded by a wet scrubber
was tested at the Reftinskaya Power Station. The unit
collects a high resistivity fly ash from the combustion of
low sulfur Ekibastuz coal. The operating parameters of
the precipitator were measured as well as the mass emis-
sions and the in-situ electrical resistivity of the fly
ash. Density, particle size distribution, electrical
resistivity, and chemical composition were determined for
collected samples of the fly ash. The fly ash was also
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characterize by x-ray diffraction and scanning electron
™copy. when a centrifual wet waii sorubjr Jtron
installed ahead of the electro^ = ^-; - .
e-Lectrostatic precipitator, the
temperature of the flue gas entering the pr.cipitator was
decreased and the moisture content increased. The
electrical resistivity of the <=!„ = v
• "y or tne fly ash was attenuated a
decade, but not enough to overcome the adverse effects of
back corona in the precioitatov T • "ects of
e precipitator. Lowering the flue gas
temperature to about 85oc by „,. aaaition J
scrubber ahead of the centrifugal scrubber reduced !s
l1 rSSiStiVity °f °- «y -" -°ther decade and
the operation of «,. precipitator without back
32.
in x. , Advances In The- Use of chemical Treatment In
le mUR r ReaUCti°n Pr°9ramS"' PreSe"ted " ™° »«tl«»»l
BilTin :r ASSOClati°" E°^ — i« -9ion Meeting,
Billings, MT, October 2-3, 1968, Paper RM-68-80.
Abstract;
Extensive in-plant tests were made on the ability of a
fuel additive containing 25S activatefl
boiler fireside tubes clean and to reduce the sulfur
simple air lancing, since the additive is a r e
m-flame catalyst, it can be applied in much smaller
quantities than is the ash with magnesium oxide addit-
"... The manganese additive is not stoiciometrically
consumed in reactions with vanadium and sulfur oxides but
regenerates itself. lt reacts with
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carbons to increase the carbon dioxide content of the flue
gas; it further lowers the ignition temperature of
combustible deposits within a furnace. By eliminating
soot, it improves the appearance of stacks. Another
factor favoring the use of the additive is that it reduces
the excess air to fuel ratio.
33. Kukin, I., "Additives Can Clean Up Oil-Fired Furnaces", Envir-
onmental Science Technology 1973, Vol. 7, No. 7, July 1973.
Abstract:
The addition of metal-containing additives to improve
boiler cleanliness, cut fireside and air heater corrosion,
and to reduce stack emissions and plumes is discussed. In
general, fuel additives should provide boiler cleanliness,
high-temperature vanadium corrosion protection, prevention
of loss of operating capacity by maintaining design steam
temperature, cold end (air heater) corrosion protection,
reduction of stack emissions from hydrogen particulate
matter and sulfur trioxide, and improvement in the
handling characteristics of ash in the flue gas in oil
fired boilers equipped with precipitators and stack
collectors. The significant fuel additives in use today
usually contain magnesium oxide (with or without small
amounts of aluminum oxide or hydrate), manganese, and
magnesium oxide with manganese. The characteristics of
each of these additives is discussed, and the efficacy of
magnesium oxide additives is compared to that of manganese
additives. Handling characteristics and air emissions are
also reviewed.
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34. Kukin, I., "Effects of Additives On Boi-ler Cleanliness and
Particulate Emissions", Procurement Int. Meet. Soc. Eng. Sci.,
1st, Tel Aviv, Israel, 1972.
Abstract:
Concentrated metal-containing additives are often used in
oil-fired furnaces to improve boiler cleanliness and
reduce the fireside and air heater corrosion. They can
also reduce stack emissions, especially hydrocarbon
particulates and sulfur trioxide. They can improve the
handling characteristics of the ash in the flue gas in
oil-fired boilers equipped with precipitators and stack
collectors. Significant fuel additives in use today
contain magnesium oxide, manganese, or magnesium oxide
with manganese. The role of MgO as a fuel oil additive
with high sulfur and high vanadium fuels is described.
Low sulfur-low vanadium fuels often contain manganese
additives. High temperature slagging and corrosion in
oil-fired boilers is reduced with a slurry containing both
MgO and Mn in combination. Manganese additives reduce
internal boiler fouling of superheaters and reheaters at
low ash input ratios. High sulfur fuels with low Vanadium
content are preferably treated with tail end chemical
injection of an active neutralizing agent to remove SO3.
Overall decrease in stack emission ideally is obtained
with a dual additive application consisting of addition of
Mn to the fuel oil and a neutralizing agent to the
economizrer outlet. Manganese additives eliminate stack
smoke, particularly in refineries burning pitch or
polymerized bottoms. Corrosion and fouling from SO3 in
coil-fired units can be eliminated by aspirating an
activated neutralizing agent in powder form into the
economizer outlet of the furnace. Other uses of
additives are discussed.
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35. Kukin, I., Bennett, R., "Chemical Control of Particulate
Emissions Through Flue Gas Conditioning", Presented at 12th
Conference on Air Quality Management in the Electric Power
Industry, The University of Texas at Austin, TX, January 28-30,
1976.
36.
Abstract;
This paper shows how the use of chemicals has become a
valuable, relatively simple and quickly installed method
for helping coal burning units to meet emissions
regulations. Faced with uncertain fuel supplies and
handicapped by a capital shortage, the electric utility
industry can look to increased use of sophisticated
chemical technology for solutions to pollution problems.
The proper application of chemical additives can allow
utilities to meet emission standards related to
particulates and plume opacity, at the same time often
allowing for improved efficiency and reduced fuel usage.
Kukin, I., Nelson, H., "The Economics of Chemical Conditioning
for Improved Precipitator Performance", Public Util. Forth,
September 23, 1976.
Abstract:
The result of power companies switching from over 2%
sulfur content coal to low sulfur coal has frequently been
a reduction of electrostatic precipitator efficiency,
resulting in particulate emissions exceeding limits.
Chemical treatment can bring the resistivity of fly ash to
the level required for high efficiency operation of the
electrostatic precipitator. The multifunctional systems
capable of optimizing fly ash resistivity, flue gas space
charge, and fly .ash particle size distribution are the
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37.
most effective. Case histories illustrate the ability of
these chemical systems to obviate the need for
multimillion dollar precipitator retrofits. Further
benefits are to be expected in new plant designs, where
savings in capital and operating costs of chemically
treated fly ash permit use of smaller, lower cost
electrostatic precipitators.
Flue gas-fly ash conditioning systems do not contribute
sulfur oxides to stack gases.
Lederman, P.B., Bibbo, P.P., Bush, J., "Sodium Conditioning
Aids Precipitation", Presented at Symposium on the Transfer and
Utilization of Particulate Control Technology, University of
Denver, CO, 24-28 July 1978.
Abstract;
Gas conditioning to aid precipitation of high resistivity
particulate has become an accepted method of solving
difficult collection problems. Until recetnly, 863 was
the standard used in cold precipitators. There was no
acceptable conditioning method for hot precipitators.
Within the past two years, Research-Cottrell has developed
sodium conditioning as an alternative for cold
precipitators and as a method of choice for aiding hot
precipitator operation.
The development of this technology encompassed laboratory
studies, pilot tests and field demonstration for a
nine-month period. Commercial installations of sodium
conditioning systems utilizing several process schemes are
in operation.
This paper discusses the laboratory methodology and pilot
tests which lead to the adoption of sodium conditioning.
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38.
Laboratory results comparing this type of conditioning to
others are presented.
The commercial applications are discussed with general
flow plans and typical results. Emissions have been
reduced by about 90% and opacity has dropped from 60-80%
to less than 20% in commercial units using sodium
conditioning.
Economics for sodium conditioning are sensitive to the
particular operating scheme and coal utilized. General
economics will be presented showing that sodium
conditioning is a competitive process for difficult fuels
and fuel switching situation. Operating costs as low as
0.012 cents per KWH can be expected.
Lederman, P.B., Bibbo, P.B., Bush, J., "Chemical Conditioning
of Ply Ash for Hot-Side Precipitation", Symposium on the Trans-
fer and Utilization of Particulate Control Technology, EPA
600/7-79-044a, February 1979.
Abstract;
The concerns over universal application of hot
precipitators to certain low alkali, low sulfur western
coals, which emerged when performance problems on a few
installations in the west were encountered (Columbia,
Comanche, Hayden), have now been eliminated with the
development of practical and proven hot precipitator
conditioning technology. Sodium conditioning has been
proven in the field as the chemical modifier of choice
for hot precipitators. It is economically attractive
compared to other means of upgrading marginal
precipitators. This technology should be considered for
new units to provide conditioned precipitator units
capable of operating on difficult ashes with the added
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benefit of some SOX removal, at lower costs than
systems not utilizing chemical conditioning.
39. Locklin, D.W., Krause, H.H., Reid, W.T., Anson, D., Dimmer,
J.P., "Fireside Additive Trials in Utility Boilers—Overview of
an EPRI Survey", Combustion, February 1980.
Abstract:
40.
This paper is based on results from EPRI Research Project
RP-1035-1. It assembles the available information and
reviews the functions and the effects of known fireside
additives, by primary chemical constituents, as used in
utility boilers firing residual oil and coal. It also
presents this information in a form that can be used by
utilities as a guide for making decisions regarding the
use of fireside additives to combat specific problems.
Martin, G.B., D.W. Perslning, and E.E. Berkau, "Effects of Fuel
Additives on Air Pollutant Emissions from Distillate-Oil-Fired
Furnaces", Environmental Protection Agency, Research Triangle
Park, NC, Office of Air Programs, Pub-AP-87, June 1971.
Abstract:
The use of fuel additives to control air pollution from
distillate-oil-fired systems was examined. The additives
tested were commercially available, proprietary
formulations; each additive was analyzed for chemical
composition and was screened for effect on emission
characteristics. Fewer than 10% of the additves affected
any pollutant reduction, whereas more than 20% increased
emissions of at least one pollutant. In a few cases,
metallic additives substantially reduced particulate
emissions, but produced a high concentration of metal
compounds in the flue gas. Additives did not reduce
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emissions of carbon monoxide, unburned hydrocarbons,
sulfur oxides, or nitrogen oxides.
41. McRanie, R.D. , J.M. Craig, and G.O. Layman, "Evaluation of
Sample Conditioners and Continuous Stack- Monitors for the
Measurement of Sulfur Dioxide, Nitrogen Oxides, and Opacity in
Flue Gas from A Coal-Fired Steam Generator", Southern Services,
Inc., Birmingham, AL, Research Department, February 1975.
Abstract;
The effectiveness of sample conditioners and continuous
stack monitors for the measurement of sulfur dioxide,
nitrogen oxides, and opacity in flue gas from a coal-fired
steam generator is reported. Individual evaluations of
the seven sample conditioners, nine SO2 analyzers, nine
NOX analyzers, and two opacity monitors included are
presented. Analyzer accuracy and sample conditioner
influence testing formed an integral part of the
evaluation. Reliable and accurate continuous stack
monitoring systems cannot be purchased off the shelf from
any manufacturer. They must be specified to sample
conditioner recommended for use on a coal-fired steam
generator. It seems to have no effect on the components
of interest in flue gas. The analyzers determined to be
most satisfactory with the SSI sample conditions for SO2
are DuPont, Mine Safety Appliances, and Beckman; for NOX
Thermo Electon and DuPont, and for opacity Lear Siegler.
Design and operation recommendations for a monitoring
system are included and the analytical techniques used in
continuous stack monitoring are discussed.
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42.
Midkiff, L.A., "Flue-Gas Conditioning Upgrades Performance,
Cuts Down Size of Precipitators", Power Vol. 123, No. 4, April
1979.
Abstract;
Chemical enhancement of precipitator efficiency, once
limited to low-sulfur retrofit applications, is now being
designed into new units. Flue gas conditioning techniques
their mechanisms and uses are described. Flue gas
conditioning began with the use of moisture to lower ash
resistivity. Today's techniques, however, include
modification of particle size, and of the space charge in
the gas phase. Hot-side as well as cold-side
precipitators can often benefit from flue gas treatments
that are properly applied. Flyash with a resistivity of
109-1010ohm-cm is considered ideal .for collection.
Methods of lowering the resistivity of the dust, such as
the use of a hotside precipitator, or chemical
conditioning in the cold-side precipitator, are
discussed. Low-resistivity conditioning and space-charge
conditioning are finally described.
43. Morris, E.B. and J.L. Schumann, "Condition Flyash with
Synthetic SO3", Power, Vol. 118, No. 7, July 1974.
Abstract:
The conditioning of fly ash with synthetic sulfur trioxide
is discussed. , It enables an electrostatic precipitator to
achieve normal collection efficiencies when cleaning flue
gas from boilers burning low sulfur, high ash coals. The
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injection of minute quantities of 803 reduces the
electrical resistivity of the fly ash to values below the
critical level of 1010 ohms-cm. These 803 quantities
range from 10 to 30 ppm by volume of the flue gas. On
site synthesis eliminates the need for storing or handling
either sulfuric acid or liquid 803. It is more economical
than installing new hot precipitators, wet scrubbers, or
special low temperature electrostatic precipitators
designed for low sulfur coal. Existing plants can upgrade
the collection efficiency of their electrostatic precip-
itators to meet new particulate codes while continuing to
burn economical low sulfur coal.
44. Oglesby, S., Jr., Nichols, G.B., "Electrical Resistivity and
Conditioning (Chapter 7)", Electrostatic Precipitation, Marcel
Dekker, Inc., New York, 1978.
Abstract;
Electrical resistivity of the dust influences electro-
static precipitators (ESP's). If the dust has high
resistivity in a single stage precipitatpr, the corna
current will be limited, reducing precipitator perform-
ance. The force holding the dust layer to the collecting
plant can be large with high resistivity dust, and high
intensity rapping is required. Such conditions can result
in larger than normal reentrainment. High electrical
resistivity of the dust can result in sparkover or back
corona. Increased thickness of the dust layer can cause a
change from a back corona to a sparking condition for the
same dust. The variations in current are such that the
maximum allowable current is approximately a decade lower
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than predicted from theoretical considerations. Volume
resistivity and temperature are inversely related at high
temperatures. Surface conduction, occurring at lower
temperatures, depends upon gaseous reaction with the
particles and the composition and morphology of the
particles. Conduction above about 250°C is controlled by
an ionic mechanism and related to the alkali metals in the
ash. Surface resistivity is governed principally by the
potassium or sodium and lithium ion concentration.
Empirical relationships are given for determining the
surface resistivity of ashes. Hot precipitators operate
at 600-800°F, where the resistivity is usually low enough
that precipitator electrical conditions are not severely
limited by breakdown of the dust layer. However, about
50% greater gas volume must be handled. Dust resistivity
can be altered changing the ash or flue gas composition.
Moisture conditioning, sulfur trioxide conditioning,
ammonia additions, and other conditioning agents are
discussed.
45. .Patterson, R., Riersgard, R., Parker R., Sparks, L.E., "Flue
Gas Conditioning Effects on Electrostatic Precipitators", Sym-
posium on the Transfer and Utilization of Particulate Control
Technology, EPA-600/7-79-044a, February 1979.
Abstract:
Flue gas conditioning agents are used primarily for
maintaining high particulate collection efficiency in
electrostatic precipitators operating on high resistivity
fly ash from low sulfur coals. Burning low sulfur coals
has been a popular method for meeting sulfur dioxide
emissions limits. Flue gas conditioning is rarely
designed into a new installation; rather, it is normally
used as a corrective method for an ailing precipitator.
_
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Many conditioning agents have been investigated for
improving the collection efficiency of ESP's. When
injected, the conditioning agents mix with the gas to form
various gaseous and particulate compounds, depending on
the flue gas composition and temperature. This program is
designed to determine the improvement in ESP performance
and the additional gaseous and particulate compounds which
penetrate the ESP.
46. Patterson, R.G., Riersgard, P., Parker, R., Calvert, S.,
"Effects of Conditioning Agents on Emissions from Coal-fired
Boilers: Test Report No. 1", EPA-600/7-79-104a, April 1979.
Abstract:
A field performance test-has been conducted on an
electrostatic precipitator (ESP) which uses sulfur
trioxide as the conditioning agent. The ESP is located at
an electric utilities power plant, burning approximately
1% sulfur coal.
Tests were conducted with and without injection of the
conditioning agent. The ESP performance was characterized
in terms of particle collection efficiency and the
chemical composition of particulate and gaseous
emissions. Fly ash resistivity and duct opac-ity were also
measured.
Results show an average increase in overall efficiency
from 80% to 95% with injection of the conditioning agent.
This is accompanied by a decrease in fly ash resistivity,
a decrease in opacity, and an increase in sulfur trioxide
concentration entering and leaving the precipitator.
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47.
Patterson, R.G., Long, J., Parker, R., Calvert, S., "Effects of
Conditioning Agents on Emissions from Coal-fired Boilers: Test
Report No. 2", EPA-600/7-79-104b, April 1979.
Abstract:
A field performance test was done on an electrostatic
precipitator (ESP) which uses Apollo Chemical Company's
LPA 445 and LAC 51B flue gas conditioning agents. The ESP
is located at an electric utilities power plant, burning
approximately 1 to 2% sulfur coal.
Tests were conducted with and without injection of the
conditioning agents. The ESP performance was
characterized in terms of particle collection efficiency
and the chemical composition of particulate and gaseous
emissions. Fly ash resistivity and flue gas opacity were
also measured.
Measurements indicate that there was no significant change
in overall penetration (0.4%) between the conditioned and
unconditioned tests. There was some evidence that the
conditioning agents reduced reentrainment during electrode
rapping and possible improved the fractional collection
efficiency slightly for particles smaller than about 5 urn
diameter.
48. Paulson, C.A./Potter, E.G., Kahanne, R. , "New Ideas on
Precipitation Technology from the Csiro Combustion Rig",
Presented at the Changing Technology of Electrostatic
Precipitation Symposium, 1974.
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49.
Abstract;
A pilot scale coal burning electrostatic precipitation rig
is described and its use for assessing the precipitation
behavior of fly ash is explained. A method of plotting
dust collection efficiencies against a combined function
of specific collection area and applied voltage has been
developed, which yields a performance line for the
precipitator handling a given dust under stated conditions
of temperature and carrier gas composition. The
performance lines permit the comparison of the
precipitation behavior of fly ashes from different coals,
and are useful in assessing flue gas additives and in
estimating the design size of full scale precipitators
from pilot plant observations. The additives investigated
include ammonia, sulfur trioxide, trimethylamine,
triethylamine, and cyclohexylamine. The performance lines
show that triethylamine at trace levels improves
precipitator performance dramatically with difficult fly
ashes, the improvement being due to agglomeration of
suspended dust and raising of breakdown voltage. Some
other additives, particularly cyclohexylamine, worsen
precipitator performance by lowering breakdown voltage and
dispersive natural dust agglomerates.
Pressey, R.E., Osborn, D., Cole, E., "Flue Gas Conditioning at
Arizona Public Service Company Four Corners Unit No. 4",
Symposium on the Transfer and Utilization of Particulate
Control Technology, EPA-600/7-79-044a, February 1979.
Abstract; '
A Flue Gas Conditioning Program was implemented between
March 22, 1977 and July 22, 1977. The objective was to
evaluate the effects of Apollo Chemical Corporation's
LPA-40 on precipitator performance and emissions.
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During the test period, the usual, operating problems were
encountered. Apollo personnel were given the task of
using EPA Method 5 to determine emission rates and
recommend adjustments and optimization of flow rates.
During the time frame of May 17 through 23, the flow rate
was increased from 0.10 to 0.15 gal/ton with a
corresponding reduction in emissions. At this point, the
unit developed high pressure differential across the
preheater. The conditioning agent was changed from LPA-40
to LPA-445. After additional testing and review, it was
determined that the differential pressure was increasing
again. At this point, the decision was. made to test the
precipitator1s performance with LPA-445 being injected at
a rate of 0.10 gal/ton and follow up with performance
testing without additives. Test results by Apollo
indicated a steady operation with desirable results.
Results of the D.R.I, conditioning tests were determined
by measuring mass loading, integrated average and
real-time particle size distribution, flue gas
composition, temperature, velocity and oxygen profiles and
precipitator performance. The test was separated into two
phases; one with conditioning and one without. The phases
were one month apart.
Chemical and physical analyses were performed to determine
the composition of the conditioning agent, its
decomposition products and both the coal and ash
composition.
50. Petersen, H.H., "Conditioning of Dust with Water-Soluble Alkali
Compounds", Symposium on the Transfer and Utilization of
Particulate Control Technology, EPA-600/7-79-044a, February
1979.
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Abstract;
A comparison of resistivity measurements and chemical
analyses of dusts from cement rotary kilns has shown a
close relationship between resistivity and the content of
water-soluble alkali compounds. Laboratory experiments
comprising impregnation of high resistivity dust samples
with various water-soluble alkali salts confirmed that
small quantities of alkali compounds were sufficient to
reduce the resistivity considerably. This led to full
scale experiments at a precipitator installation treating
high resistivity dust from a preheater kiln at a cement
plant in Brazil. Here an aqueous solution of potassium
sulfate was injected, atomized and evaporated in the gas
stream before the precipitator. An 0.4% increase in water
soluble K2O reduced the resistivity of the dust from lO1^
to 1011 ohm-cm and a corresponding improvement in
precipitator performance was observed. Recent additional
full scale conditioning experiments with potassium sulfate
and sodium chloride at a precipitator installation after a
coal-fired lime kiln in South Africa yield similar
results.
51. Radway, J.E., "Effectiveness of Fireside Additives in Coal-
Fired Boilers", Power Engineering, April 1978.
Abstract;
Benefits of using fireside additives in coal-fired boilers
are discussed. A case history is also presented. In
addition to aiding emission control and providing for
greater flexibility in coal use, chemical treatment may
improve operating reliability and increase boiler
a vai 1 abi 1 i ty .
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52.
53.
Roehr, J.D., "Flue Gas Conditioning Cold and Hot Precipit-
ators", Presented at the Southeastern Electric Exchange
Meeting, New Orleans, Louisiana, April 16-18, 1980.
Abstract:
This paper discusses the reasons for using flue gas
conditioning, the various methods and agents used and the
expected operating cost. Several agents or chemicals have
been used to achieve conditioning, such as ammonia, water,
sodium, sulfuric acid, etc. Proprietary.compounds are on
the market and are also being used. Some of these
conditioning alternatives are outlined here.
Saponja, W., "A Systematic Approach to the Application of
Electrostatic Precipitators on Low Sulfur Coals," Presented at
the Canadian Electrical Association Thermal and Nuclear Power
Section, Edmonton, Alberta, October 9, 1974.
Abstract:
Pilot plant field tests were conducted on the fly ash
removal capabilities of two identical electrostatic
precipitators installed at two coal-fired steam plants
using low ranked sub-bituminous coal with an average
sulfur content of 0.2-0.23%. At one of the plants, fly
ash was readily precipitated with the electrostatic pilot
operation, while at the other plant highly resistive fly
ash resulted in a serious reduction of effective migration
velocity. Flue gas conditioning with sulfur trioxide
(just upstream of the pilot precipitator) at the latter
plant enhanced the precipitation characteristics of the
fly ash particles, and relatively stable electrical
conditions were still evident a day after injection had
ceased. A sulfur trioxide concentration of 20-25 ppm by
volume was adequate. Hot side testing was performed to
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54.
evaluate the proposed installation of hot precipitators at
the second plant location. A reasonable range for
effective migration velocity for a full scale precipitator
is 0.30 to 0.37 ft/sec. High resistivity and back-corona
are encountered at temperatures under about 600°F.
Sodium conditioning of the high resistance coal used at
one location also reduced resistivity but was not
economically competitive with gas conditioning.
Schliesser, S.P., "Sodium Conditioning Test With EPA Mobile
ESP", Symposium on the Transfer and Utilization of Particulate
Control Technology, EPA-600/7-79-044a, February 1979.
Abstract;
The objective of this pilot program was to determine the
conditioning effects of adding anhydrous sodium carbonate
into a "cold-side" slipstream with respect to the
collection performance of an electrostatic precipitator
(ESP). A power plant combusting low sulfur, low sodium
western coal generated the high resistivity ash (2.5 x
1012 ohm-cm @ 270°F) for conditioning evaluation.
A performance evaluation was conducted on a pilot scale
precipitator which treated the base and sodium-conditioned
flyash. The program, conducted over several weeks,
consisted of twenty days of operating and testing. For
each ash species, the pilot precipitator treated 28.3
m3/min (1,000 acfm) of flue gas at an average of HO°C,
maintaining a specific collection area equal to 57
m2/m3/sec.(290 ft2/cfm).
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In situ resistivity measurements,, precipitator operating
conditions, and particulate concentration and size
distribution measurements constitute the data assembled
for the comparative demonstration.
55. Schliesser, S., "Pilot Demonstration of Sodium Carbonate Cond-
itioning", EPA-600/7-79-107, April 1979.
Abstract:
1.
2.
3.
This report describes a performance evaluation, conducted
with a pilot precipitator, studying the effects of ,
injecting anhydrous sodium carbonate to the exhaust of a
utility boiler burning Western coal.
In situ resistivity measurements, precipitator operating
conditions, particulate concentration and size
distribution measurements, and analyses of flyash
composition constitute the data assembled from this
demonstration. The following results reflect the effects
of conditioning the base flyash with a 1-2% concentration
as sodium oxide:
a sixfold reduction in resistivity (i.e., from 2.1 x 1012
to 3.7 x 1011 ohm-cm);
a threefold improvement in average current density, (i.e.,
from 6 to 18 nA/cm2);
a threefold reduction in emission rate, significant enough
to move performance from non-compliance (52.4 nanograms/
joule) to compliance (15.5 nanograms/joule); and
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4. an enhancement in the fractional efficiency
characteristics, particularly in the fine particle range.
The characteristics of sodium carbonate conditioning are
discussed, including the injection considerations,
material specifications, and the distinctive rationale for
resistivity reduction.
56. Schwarz, R.C., "Superior Fuel Oil Additives Carry Good Engin-
eering Credentials", National Engineering, Vol. 76, No. 8,
August 1972.
Abstract:
The choice of a proper fuel oil additive for the
particular problems that' beset an individual boiler is a
difficult task. Before making a choice, one should know
what types of additives are available, what mechanism each
uses to function, and possible environmental complications
that can result from the use of each. The many additives
on the market fall into four general groups: deposition
control agents, combustion catalysts, sludge solubilizers,
and water emulsifiers. Each of these functions is
discussed. Various metal compounds in fuel oil additives
include aluminum, barium, copper, lead, magnesium, and
manganese. Points worth serious consideration in evalu-
ating an additive supplier are listed. The condensation
of sulfur trioxide can cause fouling of the heat recovery
elements by a boiler system. Additives can reduce sulfur
dioxide conversion to SO3. Combustion catalysts reduce
carbon particulates such as ash in flue gas.
57. Selle, S.J., Hess, L.L., Sondreal, E.A., "Western Fly Ash
Composition as an Indicator of Resistivity and Pilot ESP
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Removal Efficiency", Presented at the Air Pollution Control
Association, Annual Meeting, 68th, Boston, MA, June 15-20,
1975, Paper 75-02.5.
58.
Abstract;
*-* ': .
Pilot-scale electrostatic precipitator performance tests
were run on a high and low resistivity western fly ash and
mixtures thereof. .The fly ashes were collected from
full-scale electrostatic precipitator hoppers and
reentrained in a flue gas of constant analysis ahead of a
120 standard cu ft/min pilot precipitator. Fly ash
composition and measured resistivity were good indicators
of precipitator performance.
Reentrained high-sodium fly ash acted as an electrostatic
precipitator conditioning agent for high resistivity fly
ash.
The addition of only 0.75% of the high-sodium fly ash
increased the effective migration velocity from 0.5 to 0.8
ft/sec at 30o°F. Similar results were obtained at 475°F.
Computer regression analysis correlating laboratory fly
ash resistivity with chemical analysis substantiated the
inverse relationship between resistivity and sodium oxide
content of the fly ash.
Southern Research Inst., Birmingham, AL, (Editors),
"Theoretical and Practical Aspects of Electrostatic
Precipitation (Second Quarterly Report)", SORI-EAS-73-017,
January 15, 1973.
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Abstract;
Field studies involving the use of ammonia vapor to
condition flue gas for electrostatic precipitation of fly
ash were performed at two Tennessee Valley Authority
coal-fired steam plants. The data from both plants, one
using low-sulfur coal and the other high-sulfur coal
indicated that the mechanism of conditioning was the same
at each location. The mechanism consists of a chemical
combination of the injected NH3 vapor with the naturally
occurring sulfuric acid vapor in the flue gases to produce
small particles of ammonium sulfate.
These small particles are charged in the precipitator,
resulting in the enhancement of the space charge, the
associated electric field, and ultimately the collection
efficiency. The electrical resistivity of the fly ash was
unchanged by the addition of NH3 vapor.
59. Spafford, R.B., Dismukes, E.B., Dillon, H.K., -"Analysis of
Thermal Decomposition Products of Flue Gas Conditioning
Agents", EPA/600/7-79-179, August 1979.
Abstract;
The report gives results of a study of reactions of
several flue gas, conditioning agents in a laboratory-scale
facility simulating conditions in the flue gas train of a
coal-burning power plant. Primary purposes of the study
were to characterize the chemical species resulting from
adding conditioning agents to flue gas and to identify
potentially hazardous chemical species originating from
the agents that may be emitted into the environment. The
compounds investigated were sulfur trioxide, ammonia,
triethylamine, sodium carbonate, ammonium sulfate, and
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diammonium hydrogen phosphate. The predominant types of
reactions observed in these experiments were thermal
decomposition fragments at lower temperatures, and
reactions with normal components of the flue gas. The
only significant environmental threat of any product
identified during this study was the formation of
N-nitrosodiethylamine as the result of injecting
triethylamine into the flue gas. This potent carcinogen
was found in trace amounts when triethylamine was injected
at 160°C.
60. Sparks, L.E., "Electrostatic Precipitators Options for
Collection of High Resistivity Fly Ash", Conference on
Particulate Collection Problems in Converting to Low Sulfur
Coals, EPA-600/7-76-016, October 1976.
Abstract;
An analysis of the technical options for collecting high
resistivity fly ash is presented. The options are a large
specific collector area at low temperatures (about 150°c),
a wet electrostatic precipitator, a moderate to large
specific collector area electrostatic precipitator
operating at either high (about 370°C) or low temperature
(about 110°c), or a moderate specific collector area for
an electrostatic precipitator operating at normal
temperature with fly ash conditioning. The advantages and
disadvantages of each option are discussed. The potential
for adverse environmental impact of the conditioning
option is also discussed.
61. Sparks, L.E., "Effect of a Flyash Conditioning Agent on Power
Plant Emissions", EPA/600/7-76/027, October 1976.
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62.
Abstract;
The report gives results of a study undertaken as a
preliminary program to provide data on the environmental
effects of a chemical flyash conditioning agent (Apollo
Chemicals conditioner LPA 402A). • Both the emissions due
to the chemical and its effect on electrostatic
precipitator (ESP) performance were investigated. The
tests were conducted over a 10-day period at Pennsylvania
Power and Light Company's Montour Plant with the plant
operating on high sulfur coal (without conditioner) and on
low sulfur coal (with and without conditioner). Sulfur
oxides (SOX), ammonia, organics, particulates, flyash
resistivity, and ESP power supply values were measured
during each test period. During conditioner injection,
the low sulfur coal flyash resitivity was reduced about
60%, although the ESP's responded slowly to this change
and its effect was not clearly evident during the test
period. The results of the SOX, ammonia, and particulate
measurements were inconclusive due both to insufficient
precision for the number of field tests and to the effect
of boiler transients. It is unlikely that the ESP will
meet particulate standards when low sulfur coal is burned
even if the conditioner is used under test conditions.
The test provided useful background information for
planning. More thorough testing at Montour seems
warranted.
Steelhammer, J.C., Nogash, D.R., Mangravite, F.J., Graffeo,
A.J., Terry, J.P., Harpel, W.L., "Effect of Chemical Additives
on Electrostatic Precipitator Performance", Presented at the
Purdue Air Quality Conference, Annual, 14th, November 12-13,
1975.
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Abstract;
Field evaluations of the effect of various chemical
additives on electrostatic precipitator performance were
performed. The coal used throughout the experiments
contained between 2 and 3% sulfur, 20-25% ash, and 5-7%
mixture. The chemical additives were fed to the flue gas
as aqueous solutions, and the chemical feed system con-
sisted of several air atomizing spray nozzles. The chem-
ical additives were fed to the flue gas for approximately
1-3 hours before particulate sampling was started.
Increases in precipitator collection efficiency were
obtained with one organic and two inorganic additives.
Efficiencies of 96.4%, 95.3%, and 94,9%, respectively,
were obtained with the additives as compared to a control
efficiency of 91.9%. The increased efficiencies appeared
to be due to space charge effects and cohesivity
modification.
63. Tseluiko, Yu. I., Chander, Yu. I., Borisovskii, L.M. , "Ammonia
Added to the Gas-and-Dust Emission of Rotary Kilns as a Factor
in the Performance of the Electrical Precipitators", Refract-
ories, Vol. 16, No. 11-12, November-December 1975.
Abstract;
Electrical precipitators are the most efficient gas
scrubbers used in the refractories industry. The degree
of dust entrapment by these device^ depends on their
design and electrical regime and on the properties of the
gas and dust mixture emitted by the kiln. The
resistivity, i.e., specific electrical resistance (SER),
of the dust is a significant factor in the performance of
the precipitator. Conditioning the flue gas with ammonia
reduces the SER of the dust so that the degree of dust
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64.
entrapment in electrical precipitators increases,
especially when the flue gas contains a large proportion
of sulfur oxides. Conditioning is at optimum with a 3-6%
ammonia solution and an ammonia consumption of 4-5 kg per
100,000 m3 flue gas.
Watson, K.S., "Australian Experience with Flue Gas Condition-
ing", Particulate Control in Energy Processes, EPA 600/7-76-
010, September 1976.
Abstract ;
Australian black coal fired in power stations usually
contains less than 1% sulfur and has 15 to 30% ash.
Target emission levels for new plants are often better
than 0.1 gm/m3 at NTP requiring collection efficiencies of
99.5%. Highly resistive fly ash predicates specific
collecting areas in excess of 80 m2/m3/s (400 ft2/1000
cfm) for cold precipitators. Early precipitators
frequently had specific collecting areas of less than 50
m2/m3/s and performed badly. Gas conditioning has been
regularly used to improve collection efficiencies since
the middle 60 's and to date has been provided on 26
precipitators on boilers from 25 to 500 MW capacity and
totalling over 4,000 MW.
Steam and/or water temperature modification, P2°5'
and S03 were used experimentally from 1955 onwards.
Sulfuric acid was first used operationally in 1964 and
anhydrous ammonia has been used since 1965.
65. White, H.J., "Electrostatic Precipitation of Fly Ash: Fly Ash
and Furnance Gas Characteristics (Part II, Section 3)", J. Air
Pollution Control Association, Vol. 27, No. 2, February 1977.
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Abstract; ,
Fly ash and furnace gas characteristics that affect design
and performance of electrostatic precipitators are
discussed. The composition, temperature, and pressure of
the gas govern the basic corona characteristics of the
precipitator, while particle size, particle concentration,
and electrical resistivity of the fly ash affect both the
corona and the particle collection properties. The gas
flow volume rate is also fundamental to precipitator
design and performance. The chemical compositions of
different kind of coal and of typical furnace gases are
present in the precipitator. The presence of sulfur
trioxide (303) in the flue gas greatly reduces the
electrical resistivity of the fly ash, by raising the
dewpoint of the flue gas. Problems of high resistivity
can result from the use of low sulfur coals; responses
include the location of precipitators ahead of, rather
than after, the air preheater, where gas temperatures of
600 to 80o°F are sufficiently high to overcome problems of
high resistivity. The chemical analysis of fly ash is
presented from literature. . Particle size distribution of
ash from power plants is given. The measurement and
significance of particle size and resistivity of fly ash
are discussed.
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2.3 Specific Installations Using FGC
As mentioned before, many power plants are using FGC to reduce
their particulate emissions. Most of the FGC systems have been
installed on the already existing ESP's. At present, about 9%
of the total MW generated by fossil fuels in the U.S.A., are
controlled by FGC. Practically all major utilities have had
some experience with gas conditioning.
The bibliography presented in this section deals with specific
installations using FGC. Many papers discuss the results of
the trial runs or field tests carried out on specific
installations. The majority of FGC systems are used on cold
side precipitators and on the plants ranging from 40 to 1000
MW.
1. Atkins, R.S., Bubernick, D.V., "Keeping Fly Ash Out of the
Stack", Environmental Science and Technology, Vol. 12, No. 6,
June 1978.
2.
Abstract;
First, two engineers from a company long in the
precipitator field explain the functions of these systems,
and what some of the design and construction methodology
is. Then two other engineers from EPA and a l-eading
research institute tell how they tested a hot-side
precipitator, and what they found.
Baxter, Walter A., "Recent Electrostatic Precipitator
Experience with Ammonia Conditioning of Power Boiler Flue
Gases", Journal of the APCA, Vol. 18, No. 12, December 1968.
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Abstract;
This paper discu-sses experiments done by Koppers Company
with ammonia conditioning of power boiler flue gases for
the purpose of improving the precipitability of the v
emitted fly ash. Chemical reactions resulting from
ammonia injection are postulated. Measurements on three
pulverized coal and two cyclone fired boilers, all of
which emit acidic ash, are described. In all five cases,
considerable but varying, increase in precipitator power
input and collection efficiency resulted when gaseous
ammonia in the amount of 15 ppm was injected between the
economizer and air preheater. The conditioned fly ash
showed decreased acidity and inconsistent change in
electrical resistivity. Unless air heater temperatures
were unusually high (>400°F), the tendency of the air
heater to plug was an additional, but unwanted, result.
At one station with high air heater outlet temperature,
ammonia injection has been adopted as a permanent solution
to community pressure for reduction of stack discharge.
Ammonia injection downstream of the air heater produced no
effect. Future plans are presented to continue the
program beyond results described here.
3. Bennett, R.P., "Fly Ash Conditioning to Improve Precipitator
Efficiency with Low Sulfur Coals", ASME Publication 76-WA/APC-
8, December 1976.
Abstract:
The use of blended chemical agents to condition coal fly
ash to improve electrostatic precipitator efficiency and
reduce particulate emissions has been subjected to
extensive field trials to verify its broad application as
a possible economic solution to pollution problems for the
electric utility industry. These chemical conditioning
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4.
agents Tiave been used with a variety of low to medium
sulfur coals resulting in precipitator efficiency
improvements of 50 to 90 percent. Emissions compliance
levels are often obtained as a result of this treatment.
The effectiveness of this system has been demonstrated on
units from 25 to 750 MW. Case history examples illustrate
the types of units treated and the extent of emissions
reductions obtained.
Bennett, R.P., Kober A.E., "Chemical Enhancement of
Electrostatic Precipitator Efficiency", Symposium on the
Transfer and Utilization of Particulate Control Technology,
EPA-600/7-790044a, February 1979.
Abstract;
It has been shown previously that chemical conditioning of
flyash can offer an immediately available alternative to
retrofit precipitators, baghouses, or other methods of
mechanical collection and usually provides, compliance
emissions at relatively low operating costs. The
equipment required involves minimum capital investment and
can usually be installed in a matter of weeks with no
significant unit downtime being involved.
It has now been demonstrated that the technique of
chemical conditioning can be expanded into a previously
untried area with the successful treatment of high-sulfur
coals, of hot precipitators, and of low-sulfur coals
utilizing a dual-injection system to provide minimum
emissions and minimum opacity. Ready availability and
minimum total costs are two advantages of this method.
The use of new conditioning agents for these processes is
continually being examined for further advances in the
state of flue gas chemical conditioning.
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5. Borsheim, R., "Flyash Conditioning_jBrings Particulate Emissions
Into Compliance", Power Eng., Vol. 81, No. 1, January 1977.
Abstract:
Low sulfur coal has unfavorable consequences on the
performance of an electrostatic precipitator. Electrical
resistivity of the fly ash, fly ash particle size
distribution, and space charge affect the performance of
the.electrostatic precipitator in a coal-burning power
plant. Fly ash conditioning involves injecting an agent
into the flue gas, making the fly ash more collectible by
the electrostatic precipitator. One commercial additive
lowers the electrical resistivity of the fly ash by
adsorbing some conductive species on the surface of the
particles. When the Corette Power Station started, burning
coal containing 0.7 to 0.9% sulfur and 8 to 10% ash, the
electrostatic precipitator performance was insufficient to
meet particulate emission standards at all loads, and the
unit was operated up to 16% below,its load rating in order
to comply. Mechanical and electrical improvements
increased efficiency somewhat, but did not permit
full-power operation. Opacity was measured constantly.
Pre-trial testing in the 148 to 150 MW range gave opacity
readings between 30 and 40%. Opacity levels dropped to 15
to 18% within 4 hours after the start of treatment. The
amount of generation lost by derating was extremely high.
Chemical treatment allowed boiler operating loads to be
raised-from an average of 148 MW to full load without
exceeding particulate emissions and plume opacity limits.
The cooling system used prior to treatment deprived the
unit of combustion air. Cooling is not longer necessary
to maximize precipitator performance. Cost of the
treatment is less than 40 cent/ton of coal. This
technology makes possible high collection efficiencies On
existing equipment at modest prices.
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Borsheim, R., Bennett, R.P., "Chemical Conditioning of Low Sul-
fur Western Coal", Presented at 39th Annual Meeting, American
Power Conference, Chicago, IL, April 1977.
Abstract:
This paper gives the results of conditioning program ...
carried out at Corette plant of Montana Power Company.
Chemical conditioning of fly ash allowed boiler operating
loads to be raised from an average of 148 MW to full 163
MW net load without exceeding particulate emissions and
plume opacity limits.
Breisch, E.W., "Method and Cost Analysis of Alternative Col-
lectors for Low Sulfur Coal Fly Ash", Symposium on the Transfer
and Utilization of Particulate Control Technology, EPA-600/7-
79-044a, February 1979.
Abstract:
Flue gas conditioning in conjunction with a conventionally
sized precipitator is shown to be the most cost-effective
means of collecting low sulfur coal, high resistivity fly
ash. The results obtained with flue gas conditioning are
both predictable and dramatic.
A case in point is the experience which Public Service
Company of Colorado has had with vendors for their new
99.2% efficient precipitator installation at Arapahoe
Station Unit 1. PSCC received bids from a number of
vendors for hot side precipitators and for cold side
precipitators with and without conditioning. The Specific
Collecting Areas proposed ranged from 295 to 334.5 for the
hot gas side precipitator. The bids for cold side ranged
from an SCA of 688 with no conditioning, down to 279 with
conditioning. PSCC chose the conditioned precipitator,
and after a year's operation of the combined installation,
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acceptance tests were conducted. The results were even
better than the original conformance tests. Emissions in
Ib/MM BTU's were 0.0161; well below the statutory limit of
0.10. Average outlet grain loadings were only 0.0079
V
gr/dscf.
8. Brines, H.G., Reveley, R.L., "Flue Gas Conditioning To Reduce
Size and Costs of a New Precipitator at PSCC Arapahoe Station
Unit No. 1", Proc. Am. Power Conf., Vol. 40, Chicago, IL, April
24-26, 1978, Sponsored by 111. Inst. of Technol. Chicago, 1978.
Abstract;
This paper is a case history of the design and selection
of a new cold-side electrostatic precipitator
installation, working with a flue gas-conditioning system
at the Arapahoe Station Unit 1, Public Service Company of
Colorado (PSCC). The installation is guaranteed to meet
particulate emission regulations and performance criteria
of the design specifications for a particulate control
device. Unit No. 1 at Arapahoe is a steam/electric
generating unit rated at 44,000 KW, It has a Babcock &
Wilcox steam generator and ball mills and was designed to
burn coal or gas. The generating unit was installed in
1950. Until the precipitator was installed, it was
equipped with only a mechanical dust collector. ,
9. Cragle, S.H., "Operating Experience with ESP Conditioning In
Relation to an Electrostatic Precipitator Upgrading Program",
Conference on Particulate Collection Problems in Converting to
Low Sulfur Coals, EPA-600/7-76-016, October 1976.
Abstract;
This report summarizes the major areas of an ongoing
electrostatic precipitator (ESP) upgrading program at
Pennsylvania Power and Light Company. Particular emphasis
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is placed on the conditioning. PSCC chose the conditioned
precipitator and after a year's operation of the combined
installation, acarea of flue gas conditioning including
eighteen months of operating experience with Apollo
Chemical Corporation products, a planned 803 injection
trial, and other potential agents.
Results of ongoing trials of Apollo products at Montour
SES on two 750 MW bituminous coal fired units are
presented. Performance data, operating problems and cost
information are covered. Eight chemical formulations have
been injected into various combinations of four locations
in efforts to improve product performance, solve air
heater plugging problems, and improve distribution of the
product on the fly ash. A significant reduction of
emissions on a difficult fly ash has been noted although
only half as great a reduction as originally expected
based on tests run with a good collecting fly ash. Air
heater plugging problems have been eliminated.
The report also covers some of the practical
considerations and potential problems that can occur in
evaluating proprietary additives.
Also, the report briefly summarizes projects on six of the
Company's ESP's including work in the following areas:
fuel quality effects; flue gas conditioning; rappers;
voltage controls; sectionalizing; gas flow distribution;
operation and maintenance; and additional dust collector
capacity.
10. Cook, R., Trykoski, M., "Sulfur Trioxide Injection at State
Line Station", EPA-600/7-76-016, October 1976.
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Abstract;
Commonwealtli Edison's efforts to overcome the problem of
electrostatic precipitator degradation through the use of
sulfur trioxide (803) flue gas conditioning is described.
An analysis of the coal (low sulfur) being burned in
Edison boilers revealed that the coal fly ash, with its
higher resistivity, reduces the current flow between the
electrodes of the electrostatic precipitator, and
therefore the precipitator performance is reduced when
compared to operation on high-sulfur coal. Evaluation of
the Edison generating system showed that a total of 22
precipitators on ten generating units ranging in size form
120 to 620 MW would suffer degradation while, burning low
sulfur coal to the point where they could no longer meet
particulate emission standards while operating at .full
load. Flue gas conditioning was sought as a means of
restoring precipitator efficiency through the lowering of
fly ash resistivity. Test results showed a dramatic
improvement in precipitator performance with flue gas
conditioning. Problems related to startup and
miscellaneous boiler .and .precipitator effects are noted.
Flue gas conditioning systems have not alleviated the
other operating problems associated with the burning of
low sulfur coal, but they are enabling these units to meet
particulate emission standards with minimal derating at a
cost far less than that of the only other feasible
alternatives, major precipitator rebuild or a new
precipitator.
11. Cook, R.E., "Sulfur Trioxide Conditioning", J. Air Pollution
Control Association, Vol. 25, No. 2, February 1975.
Abstract;
Burning of western low sulfur coal, to reduce sulfur oxide
emissions, has resulted in decreased electrostatic
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precipitator collection efficiencies. In an effort to
restore precipitator performance a flue gas conditioning
program was established. This paper discusses experience
with sulfur trioxide as a flue gas conditioning agent.
Testing at State Line Station has proven that sulfur
trioxide conditioning can effectively be used to improve
precipitator performance when burning low sulfur coals. -
12. Disrau'kes, E.B., "Conditioning of Fly Ash With Ammonia", Journal
of the APCA, Vol. 25, No. 2, February 1975.
Abstract:
This paper presents the results of an investigation of the
conditioning of fly ash with ammonia in electrostatic
precipitators of power plants operated by the Tennessee
Valley Authority. It focuses attention primarily on the
mechanisms of conditioning encountered under the
particular circumstances available for study. No effect
of ammonia on the electrical resistivity of fly ash was
evident. Instead, the effect of ammonia appeared to be an
enhancement of the space-charge component of the electric
field used .for charging and precipitating particles of fly
ash. In addition, a second effect appeared to be an
increase in the cohesiveness of precipitated ash and a
reduction in the quantity of ash reentrained during
electrode rapping. Data demonstrating the value of
ammonia conditioning for lowering the emission of fly ash
during three precipitator studies are presented. Reasons
for the ineffectiveness of ammonia conditioning during a
fourth precipitator study are discussed. In conclusion,
comments are made about the effects to be expected from
ammonia conditioning under circumstances different from
those investigated experimentally, particularly with
ammonia as a conditioning agent for fly ash from low
sulfur Western coal.
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13. Dismukes, E.B., Gooch, J.P., "Fly Ash Conditioning With Sulfur
Trioxide", EPA/600/2-77/242, December 1977.
14.
Abstract;
The report describes an evaluation of an 863 injection
system for the George Neal Unit 2 boiler of the Iowa
Public Service Company in Sioux City, Iowa. Results of
base line tests without conditioning indicate a dust
resistivity of 6 x 10 to the 12th power ohm-cm at 118°C;
the precipitator's average collection efficiency was 91.3%
at a specific collecting area of 42.8 m^/(m^/sec).
Because transformer-rectifier sets tripped out, apparently
due to ash buildup in the hoppers, only one precipitator
efficiency test was conducted with 803 system operating
continuously with all T-R sets operating. Results of this
test were: (1) specific collecting area = 41.8 m2/
(m3/sec); (2) collection efficiencies =99.27% (ASME
method), 98.96% (EPA method), and 98.78% (EPA method,
including first impinger residue); and (3) 4 x 10 to the
10th power ohm-cm dust resistivity at 143°C. An adequate
accounting was made for the fate of the injected 803.
Engel, W. and M. Meyer3cord, "Flue Gas Conditioning at Wisconsin
Power & Light to Improve Hot-side Precipitator Performance",
Presented at the Seventh Annual Technical Conference of the Air
Pollution Control Association, Midwest Section, Kansas City,
Missouri, May 22-23, 1980.
_
Abstract;
To meet emission standards for sulfur dioxide, an
increasing number so power plants have turned to western
low-sulfur coal. While this has several technical and
economic advantages, the fly ash released upon burning
these coals is unfavorable in certain installations for
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adequate collection by electrostatic precipitators
(ESPs). Reasons for this unfavorable performance have
been related to high electrical resitivity fo the fly ash
and relatively high proportion of small particle fly ash.
The cold side precipitator is still the most common means
of particulate collection, especially for plants con-
structed before the early "70s. Hot-side precipitators
are designed to eliminate the problem of high fly ash
resistivity. The concept of the hot-side ESP was based on
the correlations observed between sulfur content in coal,
flue gas temperature, and fly ash resistivity. Fly ash
resistivity drops sharply at elevated temperatures.
Placement of the precipitator prior to the air heater
where gas temperatures are typically 600-800°F, helps to
overcome the resistivity problems. Many precipitators
perform adequately in this mode. Certain low-sulfur
coals, however, continue to produce a fly ash chemistry
detrimental to precipitator operation, despite the higher
flue gas temperature.
This phenomenon was experienced when Wisconsin Power &
Light Company's Columbia Station Unit #1 went on line in
the latter half of 1975. WP&L planners designed the unit
around utilization of low-sulfur western coal, selecting
hot-side electrostatic precipitation as the means fo con-
trolling fly ash emissions.
Chemical flue gas conditioning, a technology that has been
effective in upgrading the efficiency of cold side
electrostatic precipitators, has been successfully
developed to overcome fly ash collection problems on hot-
side ESPs. Known commercially as the Coaltrol HPC system,
this new flue gas conditioning system for hot-side precip-
itators has been applied at Columbia Station, enabling the
plant to continue to comply with opacity and emission
requirements.
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15.
Ferrigan, J.J., ill, and J.D. Roehr, "SO3 Conditioning for
Improved Electrostatic Precipitator Performance Operating on
Low Sulfur Coal," Proceedings of the Symposium on the Transfer
and Utilizaton of Particulate Control Technology, Denver,
Colorado, 1979.
Abstract;
This presentation deals with a case study of a particular
utility's dilemna of having to choose an efficient and.
reliable air pollution control device to lower stack
emissions on an existing unit. The paper traces the study
from the time when excessive emissions required MW load
deratings into the decision making process, the testing
stage, and finally into the installation of SO3 flue gas
conditioning.
It points out why, in this particular case, SO3 flue gas
conditioning is a more reasonable choice than the
installation of a new cold side precipitator or fabric
filter baghouse. It clearly shows via test results
supplied by a utility based in upstate New York that SO3
flue gas conditioning enables units at their power plant
to operate well within the legal standards enforced by the
New York State Department of Environmental Conservation
(NYSDEC).
16.
"Flue Gas Conditioning", Environment Science and Technology,
Vol. 12, No. 13, December 1978
Abstract;
Low sulfur coals are increasingly used because of
stringent air pollution control restrictions on sulfur
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oxide emissions. However, low sulfur coals can present
other problems, such as flyash that is hard to capture
using an electrostatic precipitator. One solution to this
problem is to inject a chemical into the flue gas to
condition the flyash. Some recent developments indicate
that full federal acceptance of the flue gas conditioning
technology may not be too far off. Representative Paul
Rogers (D-FLA) has requested that EPA investigate chemical
conditioning with the possible goal of requiring flue gas
treatment under authority granted the agency under the
Clean Air Act of 1977. Several instances of the use of
flue gas conditioning by U.S. companies are described.
17. Green, G.P., "Operating Experience with Particulate Control
Devices", Presented at the American Society of Mechanical
Engineers, Air Pollution Control Division, National Symposium,
3rd, Philadelphia, PA, April 1973.
Abstract:
Operating experience associated with the control of
particulate emissions from steam plant units burning low
sulfur, high resistivity, western coals is reviewed.
Initially disappointing collection efficiencies with
electrostatic precipitators were improved by conditioning
the flue gas with sulfur trioxide such that its
concentration in the gas to be treated was 20 ppm.
Collection efficiencies for eight different units ranged
from 37.5-94.0% before flue gas conditioning and from
51.2-97.2% after conditioning with SO3.
-------
18.
Green, G.P., Landers, W.S., "Operating Experience With Gas
Conditioned Electrostatic Precipitators", United States-USSR
Working Group, Stationary Source Air Pollution Control Tech-
nology, Control Fine-Part., Emiss. Ind. Sources Symposium
Proc., San Francisco, CA, 1974, January 15-18, Paper 8.
Abstract:
19.
The effect of flue gas conditioning on the fly ash
collection efficiency of eight electrostatic precipitators
installed on pulverized coal burning units of the Public
Service Company of Colorado is reported. The addition of
15-20 ppm of sulfur trioxide directly to the flue gas
before the electrostatic precipitator increased collection
efficiencies from a range of 37.5-94.0% for the eight
units prior to gas conditioning to a range of 51.4-96.2%.
The low efficiencies prior to SO3 treatment were due to
the high resistivity of the untreated fly ash (10 to the
13 ohm-cm) which in turn was due to the fact that the
plant burns low sulfur western coal. Gas conditioning did
not compensate for design deficiencies other than the
resistivity problem.
Jaworowski, R.J., O'Connor, M.J., "Effect of Flue Gas
Conditioned Fly Ash on Electrostatic Precipitator Control",
Procurement of the ISA Conference and Exhibition,.Philadelphia,
PA, October 15-19, 1978.
Abstract;
Electrostatic precipitators (ESP) are designed for a
specific combination of dust fineness, resistivity, and
concentration. The ability of the ESP to cope with
changes in these parameters is limited and significant
reductions in performance often accompany changes in coal
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supplies (high sulfur coal to low sulfur coal to reduce
SC>2 emissions). This paper discusses the use of
precipitator control readings to diagnose problems
resulting from changes in fly ash resistivity, particle
size distribution, and concentration. The use of chemical
conditioning agents to overcome the adverse effects of
these changes is discussed and examples of successful
applications are given.
20. Kukin, I., Bennett, R., "Chemical Control of Particulate
Emissions Through Flue Gas Conditioning", Presented at 12th
Conference on Air Quality Management in the Electric Power
Industry, The University of Texas at Austin, TX, January 28-30,
1976.
21.
Abstract;
This paper shows how the use of chemicals has become a
valuable, relatively simple and quickly installed method
for helping coal burning units to meet emissions
regulations. Faced with uncertain fuel supplies and
handicapped by a capital shortage, the electric utility
industry can look to increased use of sophisticated
chemical technology for solutions to pollution problems.
The proper application of chemical additives can allow
utilities to meet emission standards related to
particulates and plume opacity, at the same time often
allowing for improved efficiency and reduced fuel usage.
Kukin, I., Bennett, R. , "Particulate Emission Control Through
Chemical Conditioning", Combustion Vol. 48, No. 4, October
1976.
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Abstract;
The chemical treatment of flue gases to reduce polluting
emissions was subjected to quantitative field tests to
verify its practicality as a possible economic solution to
current energy and pollution problems for electric
utilities. Chemical conditioning agents for the ash in
the flue gas improved electrostatic precipitator
collection efficiency by 50-90%, so that the units
complied with emission regulations. Some units have been
able to operate at increased capacity while still meeting
compliance levels.
22. Lederman, P.B., Bibbo, P.B., Bush, J., "Chemical Conditioning
of Fly Ash for Hot-Side Precipitation", Symposium on the Tran-
sfer and Utilization of Particulate Control Technology, EPA
600/7-79-044a, February 1979.
Abstract.;
The concerns over universal application of hot
precipitators to certain low alkali, low sulfur western
coals, which emerged when performance problems on a few
installations in the west were encountered (Columbia,
Comanche, Hayden), have now been eliminated with the
development of practical and proven hot precipitator
conditioning technology. Sodium conditioning has been
proven in the field as the chemical modifier of choice,
for hot precipitators. It is economically attractive
compared to other means of upgrading marginal
precipitators. ' This technology should be considered for
new units to provide conditioned precipitator units
capable of operating on difficult ashes, with the added
benefit of some SOX removal, at lower costs than systems
not utilizing chemical conditioning.
_
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23. Locklin, D.W., Krause, H.H., Reid, W.T., Anson, D., Dimmer,
J.P., "Fireside Additive Trials in Utility Boilers—Overview of
an EPRI Survey", Combustion, February 1980.
Abstract;
This paper is based on results from EPRI. Resear.ch Pro ject
RP-1035-1. It assembles the available information and
reviews the functions and the effects of known fireside
additives, by primary chemical constituents, as used in
utility boilers firing residual oil and coal. It also
presents this information in a form that can be used by
utilities as a guide for making decisions regarding the
use of fireside additives to combat specific problems.
24. Patterson, R.G., Riersgard, P., Parker, R., Calvert, S.,
"Effects of Conditioning Agents on Emissions from Coal-fired
Boilers: Test Report No. 1", EPA-600/7-79-104a, April 1979.
Abstract;
A field performance test has been conducted on an
electrostatic precipitator (ESP) which uses sulfur
trioxide as the conditioning agent. The ESP is located, at
an electric utilities power plant, burning approximately
1% sulfur coal.
Tests were conducted with and without injection of the
conditioning agent. The ESP performance was characterized
in terms of particle collection efficiency and the
chemical composition of particulate and gaseous
emissions. Fly ash resistivity and duct opacity were also
measured.
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Results show an average increase in overall efficiency
from 80% to 95% with injection of the conditioning agent.
This is accompanied by a decrease in fly ash resistivity,
a decrese in opacity, and an increase in sulfur trioxide
concentration entering and leaving the precipitator.
25. Patterson, R.G., Long, J,, Parker, R., Calvert, S., "Effects of
Conditioning Agents on Emissions from Coal-fired Boilers: Test
Report No. 2", EPA-600/7-79-104b, April 1979.
Abstract:
A field performance test was done on an electrostatic
precipitator (ESP) which uses Apollo Chemical Company's
LPA 445 and LAC 5IB flue gas conditioning agents. The ESP
is located at an electric utilities power plant, burning
approximately 1 to 2% sulfur coal.
Tests were conducted with and without injection of the
conditioning agents. The ESP performance was
characterized in terms of particle collection efficiency
and the chemical composition of particulate and gaseous
emissions. Fly ash resistivity and flue gas opacity were
also measured.
Measurements indicate that there was no significant change
in overall penetration (0.4%) between the conditioned and
unconditioned tests. .There was some evidence that the
conditioning agents reduced reentrainment during electrode
rapping and possible improved the fractional collection
efficiency slightly for particles smaller than about 5 urn
diameter.
26. Paulson, C.A.J., Potter, E.G., Kahane, R., "New Ideas On
Precipitation Technology From The Csiro Combustion Rig",
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Presented at the Changing Technology of Electrostatic
Precipitation Symposium, 1974.
27.
Abstract;
A pilot scale coal burning electrostatic precipitation rig
is described and its use for assessing the precipitation.
behavior of fly ash is explained. A method of plotting
dust collection efficiencies against a combined function
of specific collection area and applied voltage has been
developed, which yields a performance line for the
precipitator handling a given dust under stated conditions
of temperature and carrier gas composition. The
performance lines permit the comparison of the
precipitation behavior of fly ashes from different coals,
and are useful in assessing flue gas additives and in
estimating the design size of full scale precipitators
from pilot plant observations. The additives investigated
include ammonia, sulfur trioxide, trimethylamine,
triethylamine, and cyclohexylamine. The.performance lines
show that triethylamine at .trace levels improves
precipitator performance dramatically with difficult fly
ashes, the improvement being due to agglomeration of
suspended dust and raising of breakdown voltage. Some
other additives, particularly cyclohexylamine, worsen
precipitator performance by lowering breakdown voltage and
dispersive natural dust agglomerates.
Pressey, R.E., Osborn, D., Cole, E., "Flue Gas Conditioning at
Arizona Public Service Company Four Corners Unit No. 4",
Symposium on the Transfer and Utilization of Particulate
Control Technology, EPA-600/7-79-044a, February 1979.
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Abstract;
A Flue Gas Conditioning Program was implemented between
March 22, 1977 and July 22, 1977. The objective was to
evaluate the effects of Apollo chemical Corporation's
LPA-4CH on precipitatpr performance and emissions.
During the test period, the usual operating problems were
encountered. Apollo personnel were given the task of
using EPA Method 5 to determine emission rates and
recommend adjustments and optimization of flow rates.
During the time fram of May 17 through 23, the flow rate
was increased from 0.10 to 0.15 gal/ton with a
corresponding reduction in emissions. At this point, the
unit developed high pressure differential across the
preheater. The conditioning agent was changed from LPA-40
to LPA-445. After additional.testing and review, it was
determined that the differential pressure was increasing
again. At this point, the decision was made to test the
precipitator's performance with LPA-445 being injected at
a rate of 0.10 gal/ton and follow up with performance
testing without additives.. Test results by Apollo
indicated a steady operation with desirable results.
Results of the D.R.I, conditioning tests were determined
by measuring mass loading, integrated average and
real-time particle size distribution, flue gas composit-
ion, temperature, velocity and oxygen profiles and
precipitator performance. The .test was separated into two
phases; one with conditioning and one without. The phases
were one month apart. .
Chemical and physical analyses were performed to determine
the composition of the conditioning agent, its decom-
position products and both the coal and ash composition.
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28. Petersen, H.H., "Conditioning of Dust with Water-Soluble Alkali
Compounds", Symposium on the Transfer and Utilization of
Particulate Control Technology, EPA-600/7-79-044a, February
1979.
Abstract:
A comparison of resistivity measurements and chemical
analyses of dusts from cement rotary kilns has shown a
close relationship between resistivity and the content of
water-soluble alkali compounds. Laboratory experiments
comprising impregnation of high resistivity dust samples
with various water-soluble alkali salts confirmed that
small quantities of alkali compounds were sufficient to
reduce the resistivity considerably. This led to full
scale experiments at a precipitator installation treating
high resistivity dust from a preheater kiln" at a cement
plant in Brazil. Here an aqueous solution of potassium
sulphate was injected, atomized and evaporated in the gas
stream before the precipitator. An 0.4% increase in water
soluble K20 reduced the resistivity of the dust from 1013
to 1011 ohm-cm and a corresponding improvement in
precipitator performance was observed. Recent additional
full scale conditioning experiments with potassium
sulphate and sodium chloride at a precipitator
installation after a coal-fired lime kiln in.South Africa
yield similar results.
29. Saponja, W., "A Systematic Approach to the Application of
Electrostatic Precipitators on Low Sulphur Coals", Presented at
the Canadian Electrical Association Thermal and Nuclear Power
Section, Edmonton, Alberta, October 9, 1974.
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Abstract:
30.
Pilot plant field tests were conducted on the fly ash
removal capabilities of two identical electrostatic
precipitators installed at two coal-fired steam plants
using low ranked s.ub-bituminous coal; with an average
sulfur content of 0.2-0.23%. At one of the plants, fly
ash was readily precipitated with the electrostatic pilot
operation, while at the other plant highly resistive fly
ash resulted in a serious reduction of effective migration
velocity. Flue gas conditioning with sulfur trioxide
(just upstream of the pilot precipitator) at the latter
plant enhanced the precipitation characteristics of the
fly ash particles, and relatively stable electrical
conditions were still evident a day after injection had
ceased. A sulfur trioxide concentration of 20-25 ppm by
volume was adequate. Hot side testing was performed to
evaluate the proposed installation of hot precipitators at
the second plant location. A reasonable range for
effective migration velocity for a full scale precipitator
is 0.30 to 0.37 ft/sec. High resistivity and back-corona
are encountered at temperatures under about 600°F.
Sodium conditioning of the high resistance coal used at
one location also reduced resistivity but was not
economically competitive with gas conditioning.
Schliesser, S>, "Pilot Demonstration- of Sodium Carbonate
Conditioning", EPA-600/7-79-107, April 1979.
*
Abstracts •
This report describes a performance evaluation, conducted
with a pilot precipitator, studying the effects of
injecting anhydrous sodium carbonate to the exhaust of a
utility boiler burning Western coal.
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In situ resistivity measurements, precipitator operating
conditions, particulate concentration and size
distribution measurements, and analyses of flyash
composition constitute the data assembled from this
demonstration. The following results reflect the effects
of conditioning the base flyash with a 1-2% concentration
as sodium oxide:
1. a sixfold reduction in resistivity (i.e., from 2.1 x 1012
to 3.7 x 1011 ohm-cm);
2. a threefold improvement in average current density, (i.e.,
from 6 to 18 nA/cm2);
3. a threefold reduction in emission rate, significant enough
to move performance from non-compliance (52.4 nanograms/
joule) to compliance (15.5 nanograms/joule); and
4. an enhancement in the fractional efficiency
characteristics, particularly in the fine particle range.
The characteristics of sodium carbonate conditioning are
discussed, including the injection considerations,
material specifications, and the distinctive rationale for
resistivity reduction.
31. Southern Research Inst., Birmingham, AL, (Editors),
"Theoretical and Practical Aspects of Electrostatic
Precipitation (Second Quarterly Report)", SORI-EAS-73-017,
January 15, 1973.
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32,
Abstract;
Field studies involving the use of ammonia vapor to
condition flue gas for electrostatic precipitation of fly
ash were performed at two Tennessee Valley Authority coal
fired steam plants. The data .from both plants, one using
low sulfur coal and the other high sulfur coal indicated
that the mechanism of conditioning was the same at each
location. The mechanism consists of a chemical
combination of the injected NH3 vapor with the naturally
occuring sulfuric acid vapor in the flue gases to produce
small particles of ammonium sulfate.
These small particles are charged in the precipitator,
.resulting in the enhancement of the space charge, the
associated electric field, and ultimately the collection
efficiency. The electrical resistivity of the fly ash was
unchanged by the addition of NH3 vapor.
Sparks, L.E., "Effect of a Flyash Conditioning Agent on Power
Plant Emissions", EPA-600/7-76-027, October 1976.
Abstract:
The report gives results of a study undertaken as a
preliminary program to provide data on the environmental
effects of a chemical flyash conditioning agent (Apollo
Chemicals conditioner LPA 402A). Both the emissions due
to the chemical and its effect on electrostatic
precipitator (ESP) performance were investigated. The
tests were conducted over a 10-day period at Pennsylvania
Power and Light Company's Montour Plant with the plant
operating on Tiigh sulfur coal (without. conditioner) and on
low sulfur coal (with and without conditioner). Sulfur
oxides (SOX), ammonia, organics, particulates, flyash
resistivity, and ESP power supply values were measured
during each test period. During conditioner injection,
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the low sulfur coal flyash resistivity was. reduced about
60%, although the ESP's responded slowly to this change
and its effect was not clearly evident during the test
period. The results of the SOX, ammonia, and particulate
measurements were inconclusive due both to insufficient
precision for the number of field tests and to the effect
of boiler transients. It is unlikely that the ESP will
meet particulate standards when low sulfur coal is burned
even if the conditioner is used under test conditions.
The test provided useful background information for
planning. More thorough testing at Montour seems
warranted.
33. Steelhammer, J.C., Nogash, D.R., Mangravite, F.J., Graffeo,
A.J., Terry, J.P., Harpel, W.L., "Effect of Chemical Additives
on Electrostatic Precipitator Performance", Presented at the
Purdue Air Quality Conference, Annual, 14th, November 12-13,
1975. ' . ,.
Abstract:
Field evaluations of the effect of various chemical
additives on electrostatic precipitator performance were
performed. The coal used throughout the experiments
contained between 2 and 3% sulfur, 20-25% ash, and 5-7%
mixture. The chemical additives were fed to the flue gas
as aqueous solutions, and the chemical feed system
consisted of several air atomizing spray nozzles. The
chemical additives were fed to the flue gas for
approximately 1-3 hours before particulate sampling was
started. Increases in precipitator collection efficiency
were obtained with one organic and two inorganic
additives. Efficiencies of 96.4%, 95.3%, and 94,9%,
respectively, were obtained with the additives as compared
to a control efficiency of 91.9%. The increased
efficiencies appeared to be due to space charge effects
and cohesivity modification.
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34. Watson, K.S., "Australian Experience with Flue Gas
Conditioning", Particulate Control in Energy Processes, EPA-
600/7-76-010, September 1976.
Abstract;
Australian black coal fired in power stations usually
contains less than 1% sulfur and has 15 to 30% ash.
Target emission levels for new plants are often better
than 0.1 gms/m^ at NTP requiring collection efficiencies
of 99.5%. Highly resistive fly ash predicates specific
collecting areas in excess of 80 m2/m3/s (400 ft2/1000
cfm) for cold precipitators. Early precipitators
frequently had specific collecting areas of less than 50
m2/m3/s and performed badly. Gas conditioning has been
regularly used to improve collection efficiencies since
the middle 60's and to date has been provided on 26
precipitators on boilers from 25 to 500 MW capacity and
totalling over 4,000 MW.
Steam and/or water temperature modification, 1?2O5' NH3,
and 303 were used experimentally from 1955 onwards.
Sulfuric acid was first used operationally, in 1964 and
anhydrous ammonia has been used since 1965. Triethylamine
was first used in 1975 and is currently being evaluated.
The effect of reagents varies from station to station and
is also dependent on precipitator type and reagent
concentration. Considerable care must be given to the
injection system to allow proper mixing and sufficient
residence time. Improvements of migration velocity in
excess of 300% have been attained with SO3/H2SO4 and in
excess of 200% with ammonia, which is the preferred
reagent because of its relative safety and convenience.
Triethylamine appears to be even more effective than 803.
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Comparatively few operational problems have been reported
and most can be traced to over-conditioning or to poor
distribution. Capital costs range from 0.05 to 0.12 $/KW
and operating costs from 0.01 to 0.05 mils/KW-hr depending
on the reagent and injection concentration.
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2.4 Legal and Regulatory Aspects
There is not much literature on the regulatory aspects of using
FGC. "Enforcement Policy on Interim Particulate Controls
(Guidance)" developed recently by DOE is the only document that
deals With ±he regulatory.aspects and again, it applies to only
those power plants that are out of compliance with particulate
emission regulations.
On the legal side, many suppliers have obtained patents for
their conditioning methods using specific chemicals. The
patents are listed and described below.
Patents
1. Patent No. 3,568,403
Title: Removal of Solids from Flue Gas
Piled June 21, 1966
Author: Harry L. Richardson, Pittsburgh, Pennsylvania
Assignor to: Chemical Construction Corporation, New York, NY
Description;
Improve electrostatic pr.ecipitatj.on of entrained solids
from flue gas, which is generated by burning sulfur-con-
taining solid carbonaceous fuel, is attained by burning a
vandium-containing liquid hydrocarbon such as high vandium
content crude oil or refinery residual oil together with
the solid fuel. The vanadium which is thus added to the
combustion process is converted to vandium pentoxide which
causes at least partial catalytic oxidation of sulfur dio-
xide to sulfur trioxide, which provides improved results
and greater efficiency during subsequent treatment of the
flue gas by electrostatic precipitation, in terras of
greater solids removal from the flue gas.
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2. Patent No. 3,689,213
Title: Process for Treating Flue Gases
Filed February 19, 1970
Author: Salvatore A. Guerrieri
Description;
Liquid sulfur dioxide is vaporized and admixed with an
excess of compressed and dehumidified oxygen-containing
gas. The mixture is introduced into a converter wherein
the sulfur dioxide is converted to sulfur trioxide. The
gaseous products from the converter are introduced into a
flue gas, produced by the combustion of a low sulfur,
solid fossil fuel, prior to the passage thereof through
electrostatic precipitator means.
3. Patent No. 3,686,825
Title: Electro-Precipitation -----
Filed May 18, 1970
Author: Howard G. T. Busby, Solihull, England
Assignor to: Lodge-Cottrell Limited, Birmingham, England
Description;
An injection assembly for injecting SO3 conditioning agent
into a duct carrying gas to be cleaned to an electro-
precipitator comprises a manifold extending across the
duct and a plurality of elongated nozzles extending from
the manifold. Each nozzle and associated structure pre-
sents an aerofoil configuration of controlled dimensional
parameters so that optimum aerodynamic conditions are
obtained for the SO3 injection.
4. Patent No. 3,993,429
Title: Gas Conditioning Means
Filed May 7,- 1975
Author: William E. Archer, Huntington Beach, California
Assignor to: Wahlco, Inc., Santa Ana, California
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Description;
A method of preconditioning a boiler fuel gas mixture
containing fly ash for the efficient removal of the fly
ash by electrostatic precipitation comprising the steps
of: ..directing at least a portion of a flow of air into a
sulfur burner;' directing sulfur into said sulfur'burner;
combusting said sulfur within said sulfur burner to create
a fluid mixture including the the combustion products of
said sulfur; detecting the temperature of said fluid
mixuture exiting from said sulfur burner; selectively
varying the quantity of said portion of said directed flow
of air in response to said detecting; passing said fluid
mixture through a catalytic converter to produce a
conditioning mixture; and combining said conditioning
mixture with said flue gas mixture prior to passing said
flue gas mixture into an electrostatic precipitator.
Patent No. 4,043,768
Title: Method of Conditioning Flue Gas to Electrostatic
Precipitator
Filed April 5,1976
Authors: Robert P. Bennett, Bridgewater, New Jersey
Matthew J. O'Connor, Flanders, New Jersey
Assignors to: Apollo Chemical Corporation, Whippany,
New Jersey
Description:
A method of improving the collection characteristics of
particles entrained in a stream of particle-laden gas
formed by the burning of coal for collection by an
electrostatic precipitator, comprising forming a mixture
a. the particle-laden gas at a temperature of 590-
900°C, and
b. finely divided ammonium bisulfate; and mixture
containing 75-1,250 grams and ammonium bisulfate per
metric ton of coal burned to form said gas, and
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c. after forming said mixture, directing said gas
stream through a heat exchange means and into an
electrostatic precipitator to collect said particles
therein.
6. Patent No. 4,058,372
Title: Flue Gas Conditioning with Spiking Gas Containing
Sulfur Trioxide
Piled June 22, 1976
Author: George B. DeLaMater,. Media, Pennsylvania
Assignor to: Air Products and Chemicals, Inc., Allentown,
Pennsylvania
Description;
In a process for removing fly ash from flue gas at a
temperature of from about 140°C to about 160°C by
a. treating the flue gas"with a spiking gas containing
sulfur trioxide in a sufficient amount for
conditioning the flue gas in a mixing zone, and then
b. precipitating the fly ash from the flue gas by
electrostatic means, the improvement which
comprises:
1. forming a spiking gas containing from about
0.15 to 1.2 mol percent sulfur trioxide, and
2. maintaining the spiking gas at a temperature
sufficiently high between a temperature of
from about 300° to about 750°C such that on
treating the flue gas with the spiking gas,
the temperature of any mixture of spiking gas
and flue gas from the point of introduction
to the point of dilution as determined by the
equation.
Patent No. 4,042,348
Title: Method of Conditioning Flue Gas to Electrostatic
Precipitator
Filed August 2, 1976
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Authors: Robert P. Bennett, Bridgewater, New Jersey
Matthew J. O'Connor, Flanders, New Jersey
Alfred E. Kober, Hopatcong, New Jersey
Ira Kukin, West Orange, New Jersey
Assignors to: Apollo Chemical Corporation, Whippany,
New Jersey
Description;
A method of improving the collection characteristics of
particles entrained in a stream of particle-laden gas
formed by the burning of coal for collection by an elect-
rostatic precipitator, comprising forming a mixture of:
a. the particle-laden gas at a temperature of 590°-900°
C., and
b. Finely divided ammonium sulfate; said mixture
containing 75-1250 grams of ammonium sulfate per
metric ton of coal burned to form said gas, and
c. after forming said mixture, directing said gas
stream through a heat exchange means and into an
electrostatic precipitator to collect said particles
therein.
8. Patent No. 4,070,162
Title: Method of Agglomerating Particles in Gas Stream
Filed August 2, 1976
Authors: Alfred E. Kober, Hopatcong, New Jersey
Ira Kukin, West Orange, New Jersey
Assignors to: Apollo Chemical Corporation, Whippany,
New Jersey '"
Description;
A method of conditioning a particle-laden gas comprising
the step of forming a mixture of the particle-laden gas
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and a conditioner comprising finely divided 'urea, said
mixture being at a temperature of at least 150°C, said
conditioner being present in an amount sufficient to
produce agglomeration of said particles.
9. Patent No. 4,070,424
Title: Method and Apparatus for Conditioning Flue Gas With a
Mist of Sulfuric Acid
Filed September 21, 1976
Authors: Wallace I. Olson
Robert H. Gaunt
Jerome G. Lynch
Assignors to: UOP Inc.
Description;
Method of injecting an acid conditioning agent into a.flue
gas stream containing fly ash to be conditioned to enhance
the efficiency with which the fly ash can be electro-
statically precipitated comprising the steps of:
• , passing sulfuric acid conditioning agent under pres-
sure through a first line into a lance incorporating
a sonic atomizing nozzle;
• heating a portion of said first line adjacent said
lance so that said acid will be heated to a temper-
*
ature higher than ambient but lower than its vapor-
izing temperature and which is sufficient to
increase its temperature to at least about 93°C
before it - leaves the nozzle; and
Passing a gas under pressure through a second line
into said nozzle, said gas pressure being at least
about 10 psig higher than the liquid acid pressure,
and said nozzle incorporating means to produce sonic
vibrations capable of breaking up said liquid acid
into a mist having a mean droplet size no greater
than about 10 microns.
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10. Patent No. 4,113,447
Title: Method of Conditioning Flue Gas
Piled May 2, 1977 •
Authors: Robert P. Bennett, Bridgewater, New Jersey
Alfred E. Kofoer, Hopatcong, New Jersey
Assignors to: Apollo Chemical Corporation, Whippany
New Jersey
Description;
A method of conditioning a particle-laden gas formed by
the burning of coal comprising forming a mixture of:
a. the particle-laden gas at a temperature of 200-
900°C, and
b. , finely divided sodium bisulfate; said mixture
containing 75-1250 grams of sodium bisulfate per
metric ton of coal burned to form said gas;
and thereafter passing the mixture through an electrostatic
precipitator.
11. Patent No. 4,123,234
Title: Alkanol Amine Phosphate for Improving Electrostatic
Precipitation of Dust Particles
Filed December 12, 1977
Author: Peter H. Vossos, Lisle, Illinois
Assignor to: Nalco Chemical Company, Oak Brook, Illinois
Description;
In a method of improving the conductivity of particles
entrained in a stream of particle-laden gas formed by the
burning of coal, which particles are collected by an
electrostatic precipitator the improvement of which
comprises treating said gas containing particles prior to
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contact with the electrostatic precipitator at a
temperature not greater then about 650°F, with a
sufficient amount of resistivity-decreasing an alkanol
amine phosphate.
12. Patent No. 4,141,697
Title: Alkaline Treated Molecular Sieves to Increase
Collection Efficiency of Electrostatic Precipitators
Piled January 9, 1978
Author: Vincent M. Albanese, Lockport, Illinois
Assignor to: Nalco Chemical Company, Oak Brook, Illinois
Description:
A method of improving the conductivity of particles
entrained in a stream of particle-laden gas formed by the
burning of coal, which particles are collected by an
electrostatic precipitator which comprises treating said
gas containing the particles prior to contact with the
electrostatic precipitator at a temperature not greater
than about 1800°F with an amount of a molecular sieve
sufficient to decrease resistivity to 108-1010 ohm-cm,
• having the formula
M2/w O:A12°3:wSio2:YH2o
wherein M represents at least one cation which balances
the electrovalence of the tetrahedra, n represents the
valence of the cation, w the moles of SiC>2 and Y the moles
of H2O and then passing the gas to the electrostatic
precipitator.
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13.
14.
Patent No. 4,177,043
Title: Chemical Treatment for Improving Electrostatic
Precipitation of Dust Particles in Electrostatic
Precipitators
Filed May 22, 1978
Author: Vincent M. Albanese, Lockport, Illinois
Assignor to: Nalco Chemical Company, Oak Brook, Illinois
Description:
A method of improving the conductivity of fly ash
particles entrained in a stream of particle-laden gas
formed by the burning of coal, which fly ash particles are
collected by an electrostatic precipitator which comprises
treating said particles prior to their precipitation in an
electrostatic precipitator with a treatment chemical
comprising ammonium sulfate plus triethylamine sulfate
combined in a weight ratio of 0.5-12:1 said treatment
chemical being added at a level of from 0.125-2.0% by
weight of the fly ash present in said particle laden gas.
Patent No. 4,208,192
Title: Sonic Spray of
±n a Swirling Heated Air Stream
Filed October 27, 1978
Authors: William A. Quigley, Greenwich, Connecticut
Paul H. Sorenson, Fairfield, Connecticut
Assignors to: OOP Inc., Des Plaines, Illinois
Description:
Method of injecting an acid conditioning agent into a flue
gas stream containing fly ash to be conditioned to enhance
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the efficiency with which the fly ash can be
electrostatically precipitated comprising the steps of:
a. passing a liquid acid conditioning agent under
pressure through a first line into a nozzle at a
temperature lower than its vaporizing temperature;
b. passing a gas from a first supply source under
pressure through a second line into said nozzle,
said nozzle incorporating means to produce sonic
vibrations capable of breaking up said liquid acid
into a mist plume having an average droplet size of
about 10 microns;
c.! passing a stream of hot gas from a second supply
source having a temperature greater than the
i . . , vaporization temperature of said liquid acid and of
a value of at least about 500°F, tangentially into
, ,, . „ . one end of a cylindrical chamber in which said
.nozzle holder- and nozzle are mounted in such a
manner that said stream of hot gas will travel in a
helical manner and will entrain and vaporize
substantially all of the acid mist plume emanating
from said nozzle; and
d. passing the stream of hot gas containing said
vaporized acid into said flue gas stream after it
has traversed the length of said cylindrical
chamber.
15. Patent No. 4,213,767
Title: Electrostatic Precipitation '
Filed May 14, 1979
Author: Vincent M. Albanese, Lockport, Illinois
Assignor to: Nalco Chemical Company, Oak Brook, Illinois
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Description;
A method of improving the conductivity of particles
entrained in a stream of particle-laden gas formed by the
burning of coal, which particles are collected by an
electrostatic precipitator which comprises treating said
gas containing particles prior to contact with the
electrostatic precipitator at a temperature not greater
than about 800°F, with a resistivity decreasing amount of
hexamethylene tetramine or its water soluble salts and
thereafter passing the gas to the electrostatic
precipitator.
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1.REPOHTNO.
EPA-340/1-80-018
A. TITUS AND SUiTITUE
Annotated Bibliography of Literature on
Flue Gas. Conditioning
TECHNICAL REPORT DATA .
(Please read Instructions on the reverse before completing)
2.
S. REPORT DATE
December 1980
S. PERFORMING ORGANIZATION CODE
7.
pankaj R. Desai, Timothy K. Sutherland,
Anthony J. Buonicore
8. PERFORMING ORGANIZATION REPORT NO.
3. RECIPIENT'S ACCESSION'NO.
9>1RI«ORMINO ORGANIZATION NAME AND ADDRESS
York Services, Corporation
One Research Drive
Stamford, CT 06906
10. !
11. cbNtRACT/GRANT NO.
68-01-4138
12. SPONSORING AGENCY NAME AND ADDRESS
U. S. Environmental Protection Agency
Division.of Stationary Source Enforcement
Washington, DC 20460
13. TYPE OF REPO
Final
14. SPONSORING AGENCY CODE
IS. SUPPUSM6NTARY NOTES
Updates, will be published as available.
This report presents a comprehensive bibliography of literature on
Flue Gas Conditioning. It was developed through search of numerous
data bases including Air Pollution Abstracts (APTIC), Chemical
Abstracts, Engineering Index (COMPENDEX), Environmental Abstracts
(ENVIROLINE), National Technical Information Service (NTIS), etc.
Publications of Electric Power Research Institute, Edison Electric
Institute, and Department of Energy are also included. Information
is provided on the assigned U.S. patents related to Flue Gas
Conditioning. The literature is organized under four separate
categories: (i) general theory, (ii) specific methods and agents,.
(iii) specific installations using FGC, and (iv) legal and
regulatory aspects.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lOENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Flue gas conditioning, fly ash con-
ditioning agents, low sulfur coal
burning, high resistivity fly ash
collection, particulate emission
reduction, precipitator collection
efficiency.
18. DISTRIBUTION STATEMENT
19. SECURITY
eport)
20. SECURITY CLASS (Thispage)
22. PRICE
EJ"A Form 2220-1 O-73)
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