Air Pollution Control Technical Library
Achieving Low Particulate Emissions with Electrostatic Precipitators
Robert Mastropietro, March 1994
Abstract
A great deal of literature has been published in recent years maligning electrostatic precipitators (ESP) as not being
effective in achieving low emissions, or as being less effective than fabric filters in collecting fine particulate.
This observation is not valid, provided the ESP is properly sized. The misconception comes from comparing modern high
efficiency fabric filters, with 1950-1970's vintage ESP's…
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Air Pollution Control for Waste to Energy Plants
Mark Sankey, April 1997
Abstract
Recent regulations require owners and operators of many waste-to-energy facilities to upgrade their existing air pollution
control equipment. While it makes sense for some of these to install systems which meet BACT (Best Available Control Technology)
standards, for others such a route could be less than the best choice. For the purpose of this discussion we will consider BACT
standards to be at least 90% S02 reduction and 95% HCl reduction…
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Current U.S. Air Pollution Control Technologies & Future Trends
William Morris, July 2002
Abstract
The North American air pollution control market continues to evolve in response to new and changing environmental regulations,
new technologies, and even some new applications of proven technologies. Some of the future changes expected in the environmental
regulations include tighter emissions regulations on SO2, NOx, PM-2.5, Mercury control and air toxics such as lead, and cadmium…
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Effective Use of both COHPAC™ & TOXECON™ technologies as the "Technology of the Future" for Particulate & Mercury Control on Coal Fired Boilers
Richard Miller, Ramsay Chang & Jean Bustard - December 2003
Abstract
With the pending legislation for reduction of mercury emissions as well as other pollutants from the combustion of coal from power plants, several programs are currently underway to demonstrate mercury emissions from existing facilities. This paper will discuss the success of utilizing EPRI's COHPAC™ and TOXECON™ technologies as offered commercially by Hamon Research-Cottrell for the reduction of mercury and other pollutants, including fine particulates.
The success of this unique multi-pollutant control technology, to remove mercury and dioxins from flue gas was adopted by American Ref-Fuel, for use at their SEMASS waste-to-energy combustion facility located in Massachusetts. It has also been demonstrated for coal-fired power plant applications during the first full-scale DOE test program conducted by ADA-ES at Alabama Power E.C. Gaston Station. Results from SEMASS and this initial DOE demonstration program, plus additional released information from the second phase of this DOE program which starting in early 2003, will be discussed in this paper...
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Electrostatic Precipitator Rebuild Strategies for Improved Particulate Emissions
Robert Mastropietro, December 2002
Abstract
Due to governmental legislation, which reduced allowable particulate emission in the 1972-1978 time period, there were a great
number of utility electrostatic precipitators (ESPs) installed in that era. This "aging fleet" of ESPs is now about 25-30 years
old, and are often the highest emitting sources (in terms of particulate matter) within utility systems. These older units were
designed (and are Grand-Fathered) to achieve 0.1 LB/MMBTU of particulate matter, instead of modern NSPS of 0.03 LB/MMBTU.
Many of the units are experiencing problems with the internal electrodes corroding or sustaining rapper damage, to the point
of failure…
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Electrostatic Precipitator Upgrade Strategies - Get the Most From What you Have
Robert Mastropietro, Mark Sankey, April 1997
Abstract
Over the years, many power generation facilities have installed electrostatic precipitators to control particulate emissions.
With the Clean Air Act Amendments of 1990, power plants must determine if their existing precipitator equipment is adequate.
Many power companies have already completed this task and upgraded or replaced equipment, but the work is now in progress for
many others. In every case the condition and capabilities of the existing equipment must be assessed and weighed against the
applicable, new regulations. Assessment includes consideration of the mechanical and structural condition of a precipitator
as well as particulate collection performance. A unit which is large enough to achieve the necessary performance may only
need refurbishing…
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Electrostatic Precipitators for Refinery Fluid Catalytic Cracking Units
Robert Mastropietro, John Cunic, May 2001
Abstract
Electrostatic precipitators have been used for many years to collect particulate coming from refinery FCCUs
(Fluidized Catalytic Cracking Units). These ESPs must be designed to accommodate particulate that can have very high
resistivity and may create extreme back-corona situations. Additionally, after having been processed by a series of upstream
cyclones, the particulate entering the ESP can have an extremely fine particle size distribution. Because of this
pre-collection, the required efficiencies are deceivingly low. Yet even efficiencies of less than 90% can be difficult because
of the fine particle size. To further acerbate this difficulty, current run plans call for continuous FCCU operation for up
to five years. These factors combine to create an ESP application that is quite different from any other common industrial
application
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HCl Emissions Controls at Alcan Berea
William Morris, May 2002
Abstract
This paper describes the design, initial operation and performance testing of an Acid Gas Removal (AGR) system installed by
Hamon Research-Cottrell (HR-C) during Phase II of the acid gas removal project at the Alcan Rolled Products-Recycling Facility
in Berea, Kentucky. This facility process recycled aluminum cans into high purity ingots for manufacturing new cans. It is
reported to be the largest facility of its kind in the US. The combined flue gas from the line #2 decoater and one (1)
holding furnace is processed by the system to control emissions of hydrogen chloride (HCl) gas and particulates.
The AGR system consists of a Quench Reactor, Dry Venturi, and High Pressure Pulse Jet Fabric Filter. Each Quench Reactor
vessel uses a six (6) air atomized nozzles to disperse the lime slurry for acid gas control. The PJFF consists of four (4)
modules arranged in two rows…
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Impacts Of ESP Performance on PM-2.5
William Morris, May 2002
Abstract
Potential legislation concerning PM-2.5 (particulate matter less than 2.5 microns) has been under discussion for several years,
in the USA. It is unclear today what form the final legislation will take, concerning testing of stationary sources. Ambient
air quality is the issue, and stack emissions from stationary sources are only one contributor to atmospheric concentrations
of PM-2.5. Since PM-2.5 can come from a wide variety of sources (road dust, automobile exhausts, farm fields, acid condensation,
etc.), PM-2.5 from stationary sources is only indirectly linked to total atmospheric PM-2.5. Also the PM-2.5 generated by
stationary sources can come from two distinctly different sources…
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Particulate Control for Biomass Fired Boilers
Robert Mastropietro, May 1996
Abstract
Electrostatic precipitators (ESP's) have been providing dependable service as dry dust collectors for biomass applications
for more than 20 years. During this period the industry has moved from the experimental, to cautious, to standard practice
stages. ESP's have been used on woodwaste, sludge, chicken litter, grape vine prunings, bagasse, etc. Design standards have
been developed to address most sizing issues including fly ash chemistry and resistivity. Salt soaked bark applications have
been encountered and successfully controlled. PM-10 regulations have sometimes been an issue and can be successfully
demonstrated with an ESP. Lastly the main problem area with operation of ESP's on biomass has been internal fires. Specific
operating conditions have been successfully demonstrated to control fires, by controlling boiler operating conditions
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Practical Problems with Electrostatic Precipitators can provide significant contribution to science
Robert Mastropietro, September 1998
Abstract
Electrostatic precipitators (ESPs) have served industry as dust and aerosol collectors since being invented by Frederick
Cottrell in 1907. Since that time, the design and sizing of ESPs has changed dramatically. Required emissions from ESPs
have decreased from those required for "good neighbor policy", to those required to protect public health (PM-10/PM-2.5)
or sensitive downstream equipment. Additionally industry is constantly changing processes and operating conditions to which
we must apply ESPs, which create applications challenges. Lastly the ESP suppliers themselves are making changes to the
electrode geometry, insulator assemblies, boundary clearances, etc. to make the product less costly. Occasionally changes
result in a practical problem with the new ESP design, which require solutions. However, these practical problems opportunity
and incentive to advance the science of electrostatic precipitation…
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Precipitator Replacements and Rebuilds. Where does the money go?
Mark Sankey, August 1995
Abstract
During the next several years many electrostatic precipitator owners in the power industry will be faced with the need to
upgrade or replace existing equipment because of changes in regulations, deadlines for reduction in SO2 emissions, and the
age and condition of existing precipitators. This study is a planning guide for precipitator upgrades. The equipment selected
is representative for many actual situations. Cost sensitivity to collection performance, precipitator configuration, outage
requirements, and other factors is shown. Cost differences between rebuilds and complete replacements are also shown.
The study focuses on the precipitator and basic auxiliaries and presents a comparison of potential upgrade options for a
typical existing precipitator installation…
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Prevention of Fires and Explosions in Electrostatic Precipitators
Robert Mastropietro, May 1995
Abstract
In the past, two types of fires or explosions have been observed in electrostatic precipitators (ESP). The first type has
been a fire in the dust collected on the ESP collecting plates or in the ESP hoppers. For this type of fire, carbon is the
combustible material. A second type of fire occurs when a flammable mixture of gases in the ESP explodes. Carbon monoxide
or natural gas have typically been present when these explosions occurred. Suspended dust type explosions, i.e. "grain elevator" type, have not been observed, but may also be possible. Because an ESP inherently provides a source of ignition
(sparking between electrodes), control of fires has been accomplished by controlling flue gas oxygen levels. The following
discussion is basically a compilation of information collected from various technical sources on the inflammability limits
of various gas mixtures…
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Rebuild & Enlargement of Existing Weighted Wire ESPs as a result of coal switching
Robert Mastropietro, December 1992
Abstract
A recent trend in the electric power generating industry is toward the use of low-sulfur coal in facilities originally
equipped with electrostatic precipitators that were designed to operate with high-medium sulfur coal. Although this trend
has been triggered by a variety of reasons, its driving force is compliance with the sulfur dioxide reduction requirements
of the Clear Air Act Amendment's Title IV. Although the reduced sulfur content in the coal helps to lower S02 emissions,
it produces a corresponding increase in particulate resistivity and a substantial degradation in precipitator performance.
Several available technologies exist that can enhance ESP performance and restore its operation to performance levels near,
or equal to, that experienced before the switch of coal. One technology involves the rebuilding and enlargement of the existing
ESP to meet the new flue gas conditions created by the switch to low-sulfur coal…
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The Use of Treatment Time and Emissions instead of SCA and Efficiency for sizing ESPs
Robert Mastropietro, August 1997
Abstract
The first commercial electrostatic precipitator (ESP) was developed in 1907. Since that time many types of mathematical
models have been used to calculate ESP sizes relative to desired performance. This paper discusses several of these historical
approaches, before describing a treatment time vs. emissions approach to ESP sizing. The use of treatment time vs. emissions
for sizing ESP's has become a common approach to this calculation, due to changes in ESP designs and performance requirements…
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Results of Activated Carbon Injection for Mercury Control upstream of a COHPAC Fabric Filter
Richard Miller, May 2003
Abstract
Injecting activated carbon upstream of a COHPAC fabric filter represents one of the most cost-effective approaches
of reducing mercury emissions from coal-fired boilers. This configuration is referred to as TOXECON, and it can produce
high levels of mercury reduction, up to 90%, at relatively low carbon feed rates, 2-3 lb/Macf, without contaminating
the bulk of the ash. This paper will provide results from short-term tests conducted on coal-fired boiler flue gas
and the most recent results from a year-long test that began in March 2003. This new long-term program is being
conducted by ADA-ES working in partnership with the Department of Energy National Technology Laboratory (NETL),
EPRI and a number of power generators and vendors. These tests are being conducted on ? of Alabama Power's E.C.
Gaston Unit 3 COHPAC fabric filter. Results from a short-term test program at this site in 2001 showed high mercury
removal efficiencies were possible, but operational restraints prevented running these conditions for extended periods
and could not provide information on long-term impact on fabric filter performance. The current program will evaluate
the long-term (~ 1 year) performance of activated carbon for mercury control and its affect on bag life, pressure drop
and balance-of- plant equipment. The paper will also present progress on a new $50M five-year demonstration program of
TOXECON that will take place at the We Energies Presque Isle Power Plant. This project was recently awarded under the
Clean Coal Power Initiative.
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Reviving an Electrostatic Precipitator
Peter Aa, November 1991
Abstract
Although electrostatic precipitators (ESPs) have been in use for many years to collect dusts from manufacturing operations in the pulp and paper, steel, cement, chemical, and petrochemical industries, their largest application today is in the removal of flyash from coal-fired boilers employed in steam or electric power generation. Compared with other dust-collection systems, ESPs are highly efficient in removing solid or liquid (mist) particles from effluent-gas streams. This is because, in the cleaning process, the forces in a precipitator directly work only on the suspended particles themselves, not on the entire gas stream.
Most of the existing ESPs have been in service for 15 years or more, and their performance has inevitably deteriorated with age. In light of increasing pressure to comply with local and national air-quality standards, it is imperative that these units work properly at all times. Otherwise, plants could face fines, curtailed production, or even complete shutdowns…
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Wide Plate Spacing for Precipitators
Peter P. Bibbo, October 1988
Abstract
The benefits of wide plate spacing probably are not totally exploited in most industrial processes. Higher collection efficiency at lower overall cost may be a valid claim in certain few benign precipitator applications, but equivalent performance at lower cost could probably be achieved in a very large number of new and existing installations. Yet there are other applications where wide plate spacing would lead to decreased performance and potentially higher maintenance cost.
Where it can be a benefit, wide plate spacing delivers at least equivalent performance only if the applied voltage is proportionally increased. Theoretically, the increase in performance is due to the higher electric field at the collecting plate. The field at the collecting plate is understood to be the primary variable in predicting collection efficiency. But before knowing why this does not always work, it is first necessary to understand some basics, such as what dust properties affect precipitation, and how wide is wide?…
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Full-Scale Evaluation of Mercury Control with Sorbent Injection and COHPAC at Alabama Power E.C. Gaston
Richard Miller & Co-Authors, February 2002
Abstract
The overall objective of this project was to determine the cost and impacts of mercury control using sorbent injection into a COompact Hybrid PArticulate Collector (COHPAC) at Alabama Power's Gaston Unit 3. This test is part of a program funded by the Department of Energy's National Energy Technology Laboratory (NETL) to obtain the necessary information to assess the costs of controlling mercury from coal-fired utility plants that do not have scrubbers for SO2 control. The economics will be developed based on various levels of mercury control.
Gaston Unit 3 was chosen for testing because COHPAC represents a cost-effective retrofit option for utilities with existing electrostatic precipitators (ESPs). COHPAC is an EPRI patented concept that places a high air-to-cloth ratio baghouse downstream of an existing ESP to improve overall particulate collection efficiency. Activated carbons were injected upstream of COHPAC, downstream of the ESP to obtain performance and operational data. Residue hopper ash and carbon samples were collected to evaluate the impact ash properties. A series of parametric tests were conducted to determine the optimum operating conditions for several levels of mercury control up to 90% mercury removal. Based on results from these tests, a longer-term test with one sorbent and optimized conditions was conducted to assess impacts to COHPAC and auxiliary equipment.
Results were very encouraging with up to 90% removal of mercury for short operating periods using powdered activated carbon. A significant increase in cleaning frequency of the COHPAC baghouse occurred with the injection of activated carbons. During the long-term tests an average mercury removal efficiency of 78% was measured. The PAC injection rate for the long-term tests, 1.5 lbs/Mmacf, was chosen to maintain COHPAC cleaning frequency below 1.5 pulses/bag/hour..
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Advancement in Air Pollution Control for Pulp and Paper Industry
Prakash Dhargalkar & Jose Astolphi, Jr, November 1997
Abstract
Control of air pollution from pulp and paper plants is a unique challenge. This paper presents case studies related to
design and operation of electrostatic precipitators (ESPs) for recovery and wood-fired boilers. The increasingly stringent
emission requirements, as well as changes in the boiler design, have necessitated improvements in the ESP technology.
Highlights of ESP features - including discharge and collecting electrodes, electrical sectionalization, microprocessor controls,
rappers, etc. will be presented in this paper. Recent enhancements in the technology will be discussed. Data from operating
plants will be presented to illustrate how emission levels can be achieved reliably...
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Application of U.S. Pollution Control Systems in Taiwan
Prakash Dhargalkar, November 1989
Abstract
Environmental pollution has become a major concern worldwide. Many countries are imposing stringent regulations on
existing power plants and industrial manufacturing facilities. All new plants are required to comply with tight emission
limits for various toxic pollutants. Many emission control technologies developed in the U.S. for various applications
are capable of controlling pollution from power plants, waste incineration facilities as well as other manufacturing
processes. Long term operating experience has demonstrated high reliability consistent with the overall plant operation.
Also, reliable techniques and equipment have been developed and installed for continuous monitoring of emission levels
of various pollutants. The U.S. experience is available for application in Taiwan, which has undertaken a major task of
environmental protection...
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An Integrated Waste Management Plant in Italy
Prakash Dhargalkar, June 1991
Abstract
Disposal of residential municipal waste poses a growing problem in many locations throughout the world due to limited availability of landfills. Most existing landfills arm approaching their capacities while the opening of new landfills has become increasingly difficult due to stringent regulations. Various types of combustion technologies have been employed to recover energy while simultaneously reducing the amount of waste to be landfilled. Incineration of wastes has been adopted by many communities to reduce the volume of the refuse to be landfilled; typically a reduction of up to 80 percent is possible. Recycling, although attractive, does not provide a total solution since it results in less than 50 percent waste reduction.
Mass burning incineration of wastes with simultaneous production of steam and power is the most widely used approach to-date. It not only reduces the waste volume but also recovers useful energy, which improves the overall economics. However, public concerns over the emissions from such plants have stimulated researchers and government agencies worldwide to explore different means of waste reduction as well as to focus on control of emissions. All new incineration plants are equipped with state-of-the-art emission control systems.
This paper describes a unique waste management system under construction in Grove, located in the famous wine region of Chianti, Italy. Design highlights of this novel process and the air pollution control system are presented...
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Control of Emissions from Municipal Solid Waste Incinerators
Prakash Dhargalkar, April 1988
Abstract
Increasing attention is being given to recovery of energy from incineration of municipal garbage as a means of managing waste disposal problem. Recent regulations have specified maximum acceptable emission levels for various pollutants from these waste-to-energy facilities. An emission control system, consisting of a quench reactor (dry scrubber), dry venturi and a fabric filter, has not only demonstrated compliance with the specified emission levels, but has achieved even lower emissions for many pollutants including dioxins/furans in full-scale plants. Operating experience and performance data from two different facilities is presented in this paper...
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HI-R Electrostatic Precipitators for a Belgian Steel Plant
Prakash Dhargalkar & Philippe Delvaux, November 1991
Abstract
Research-Cottrell's Hi-RTM electrostatic precipitator technology has been selected for the control of particulate emissions from a major steel plant in Belgium. ESP's have been, or will be, installed on various gas streams including two blast furnaces, converter house and a steel plant. Innovative design and construction features have been incorporated to permit installation of the ESP's within the constraints of the operating practice and the layout of the existing facility. Dust emissions will be curtailed significantly when all the ESP's are in operation by 1992. Design features of the various ESP's and performance data from the completed blast furnace installation are presented in this paper...
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Enhancing Aging ESP Performance Utilizing COHPAC Hybrid Fabric Filter Technologies
Richard Miller, April 2003
Abstract
After many years of service, there are an increasingly large amount of existing electrostatic precipitators installed on numerous applications, including coal-fired boilers, municipal waste combustors, and other non-combustion applications such as cement kilns, steel applications, etc. that can no longer meet their original, current and/or future emission control requirements. These requirements can be either; total particulates, fine particulates, metals and even toxins such as mercury, dioxins, etc. One method that has been successfully applied to enhance the ability of ESP's to meet these requirements has been the installation of COHPAC fabric filter technology in series with the existing ESP collectors. This paper will provide an overview of this technology and its ability to improve the performance of existing ESP collectors...
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Dry Electrostatic Precipitators-Still the Choice for Particulate Collection On Oil-Fired Boilers
Robert Mastropietro , December 2005
Abstract
Dry electrostatic precipitators (ESPs) have been used to collect particulate on oil-fired boilers for about 40 years. Although other particulate collection technologies have made inroads on coal-fired boilers, ESPs continue to be the best choice for particulate collection on oil fired boilers. This dependence on ESPs is due to issues such as high sulfuric acid levels, hygroscopic/sticky fly ash, fly ash fire potential, and low cost of ESPs for the oil-firing, feature a combination of low cost, reliable operation, and low particulate emissions. It is anticipated that ESPs will continue to provide reliable service on oil-fired boilers for many years to come...
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Particulate Control for Biomass Fired Boilers SA
Robert Mastropietro , May 2004
Abstract
Electrostatic precipitators (ESP's) have been providing dependable service as dry dust collectors for biomass applications for more than 25 years. During this period the industry has moved from the experimental, to cautious, to standard practice stages. ESP's have been used on woodwaste, sludge, chicken litter, human sewerage sludge, sunflower husks, bagasse, etc. Design standards have been developed to address most sizing issues including fly ash chemistry and resistivity. Salt soaked bark applications have been encountered and successfully controlled. PM-10 regulations have sometimes been an issue and can be successfully demonstrated with an ESP. Lastly the main problem area with operation of ESP's on biomass has been internal fires. Specific operating conditions have been successfully demonstrated to control fires, by controlling boiler operating conditions...
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