From: "Steinwurtzel, Robert N." <rsteinwurtzel@bakerlaw.com>

To: Chuck French/RTP/USEPA/US@EPA 

Cc: Russell Kemp <rkemp@environcorp.com>, "DeLaquil, Mark" <mdelaquil@bakerlaw.com>, 

"Steinwurtzel, Robert N." 

<rsteinwurtzel@bakerlaw.com>

Date: 02/11/2011 05:36 PM 

Subject: FW: ABR Response to MACT/RR Issues 

Chuck, please find attached ABR's initial response to the issues identified by EPA during the conference 

call conducted on Wednesday, February 9. We appreciate the opportunity to confer with the agency and 

to submit the attached comments. We should discuss convening again, either in person or by phone, in 

the near future. Regards, Robert. 

My Bio | Web site | 

V-card 

T 202.861.1708 

F 202.861.1783 

M 

www.bakerlaw.com

Robert Steinwurtzel 

rsteinwurtzel@bakerl 

aw.com 

Baker & Hostetler 

LLP 

Washington Square, 

Suite 1100 

1050 Connecticut 

Avenue, N.W. 

Washington, D.C. 

20036-5304 

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(See attached file: Ltr to Chuck French.pdf)(See attached file: NESHAPProposal.pdf)(See attached file: ffshakerFactSheet.pdf) 






 EPA-452/F-03-024

Air Pollution Control Technology 

Fact Sheet

EPA-CICA Fact Sheet Fabric Filter

1 Mechanical Shaker Cleaned Type

Name of Technology: Fabric Filter - Mechanical Shaker Cleaned Type

 - Mechanical Shaker Cleaned Type with Sonic Horn Enhancement

 (also referred to as Baghouses)

Type of Technology: Control Device - Capture/Disposal

Applicable Pollutants: Particulate Matter (PM), including particulate matter less than or equal to 10

micrometers (μm) in aerodynamic diameter (PM10), particulate matter less than or equal to 2.5 μm in

aerodynamic diameter (PM2.5), and hazardous air pollutants (HAPs) that are in particulate form, such as most

metals (except mercury is the notable exception, as a significant portion of emissions are in the form of

elemental vapor).

Achievable Emission Limits/Reductions:

Typical new equipment design efficiencies are between 99 and 99.9%. Older existing equipment have a range

of actual operating efficiencies of 95 to 99.9%. Several factors determine fabric filter collection efficiency.

These include gas filtration velocity, particle characteristics, fabric characteristics, and cleaning mechanism.

In general, collection efficiency increases with increasing filtration velocity and particle size. 

For a given combination of filter design and dust, the effluent particle concentration from a fabric filter is nearly

constant, whereas the overall efficiency is more likely to vary with particulate loading. For this reason, fabric

filters can be considered to be constant outlet devices rather than constant efficiency devices. Constant

effluent concentration is achieved because at any given time, part of the fabric filter is being cleaned. As a

result of the cleaning mechanisms used in fabric filters, the collection efficiency is constantly changing. Each

cleaning cycle removes at least some of the filter cake and loosens particles which remain on the filter. When

filtration resumes, the filtering capability has been reduced because of the lost filter cake and loose particles

are pushed through the filter by the flow of gas. As particles are captured, the efficiency increases until the

next cleaning cycle. Average collection efficiencies for fabric filters are usually determined from tests that

cover a number of cleaning cycles at a constant inlet loading. (EPA, 1998a)

Applicable Source Type: Point

Typical Industrial Applications:

Fabric filters can perform very effectively in many different applications. Common applications of fabric filter

systems with mechanical shaker cleaning are presented in Table 1, however, fabric filters can be used in most

any process where dust is generated and can be collected and ducted to a central location. Sonic horn

enhancement of mechanical shaker cleaning is generally used for applications with dense particulates such

as utility boilers, metal processing, and mineral products.
EPA-CICA Fact Sheet Fabric Filter

2 Mechanical Shaker Cleaned Type

Table 1. Typical Industrial Applications of Shaker Cleaned Fabric Filters (EPA, 1998a)

Application Source Category Code (SCC)

Utility Boilers (Coal) 1-01-002...003

Non-Ferrous Metals Processing 

(Primary and Secondary):

Copper 3-03-005, 3-04-002

Lead 3-03-010, 3-04-004

Zinc 3-03-030, 3-04-008

Aluminum 3-03-000...002

3-04-001

Other metals production 3-03-011...014

3-04-005...006

3-04-010...022

Ferrous Metals Processing:

Coke 3-03-003...004

Ferroalloy Production 3-03-006...007

Iron and Steel Production 3-03-008...009

Gray Iron Foundries 3-04-003

Steel Foundries 3-04-007,-009

Mineral Products:

Cement Manufacturing 3-05-006...007

Coal Cleaning 3-05-010

Stone Quarrying and Processing 3-05-020

Other 3-05-003...999

Asphalt Manufacture 3-05-001...002

Emission Stream Characteristics:

a. Air Flow: Baghouses are separated into two groups, standard and custom, which are further

separated into low, medium, and high capacity. Standard baghouses are factory-built, off the shelf

units. They may handle from less than 0.10 to more than 50 standard cubic meters per second

(sm3

/sec) (“hundreds” to more than 100,000 standard cubic feet per minute (scfm)). Custom

baghouses are designed for specific applications and are built to the specifications prescribed by

the customer. These units are generally much larger than standard units, i.e., from 50 to over 500

sm3

/sec (100,000 to over 1,000,000 scfm). (EPA, 1998b)

b. Temperature: Typically, gas temperatures up to about 260°C (500°F), with surges to about 290°C

(550°F), can be accommodated with the appropriate fabric material. Spray coolers or dilution air

can be used to lower the temperature of the pollutant stream. This prevents the temperature limits

of the fabric from being exceeded. Lowering the temperature, however, increases the humidity of

the pollutant stream. Therefore, the minimum temperature of the pollutant stream must remain

above the dew point of any condensable in the stream. The baghouse and associated ductwork

should be insulated and possibly heated if condensation may occur. (EPA, 1998b)
EPA-CICA Fact Sheet Fabric Filter

3 Mechanical Shaker Cleaned Type

c. Pollutant Loading: Typical inlet concentrations to baghouses are 1 to 23 grams per cubic meter

(g/m3

) (0.5 to 10 grains per cubic foot (gr/ft3)), but in extreme cases, inlet conditions may vary

between 0.1 to more than 230 g/m3

 (0.05 to more than 100 gr/ft3). (EPA, 1998b)

d. Other Considerations: Moisture and corrosives content are the major gas stream characteristics

requiring design consideration. Standard fabric filters can be used in pressure or vacuum service,

but only within the range of about ± 640 millimeters of water column (25 inches of water column).

Well-designed and operated baghouses have been shown to be capable of reducing overall

particulate emissions to less than 0.05 gr/m3

 (0.010 gr/ft3), and in a number of cases, to as low as

0.002 to 0.011 g/m3

 (0.001 to 0.005 gr/ft3). (AWMA, 1992)

Emission Stream Pretreatment Requirements:

Because of the wide variety of filter types available to the designer, it is not usually required to pretreat a waste

stream’s inlet temperature. However, in some high temperature applications, the cost of high temperatureresistant bags must be weighed against the cost of cooling the inlet temperature with spray coolers or dilution

air (EPA, 1998b). When much of the pollutant loading consists of relatively large particles, mechanical

collectors such as cyclones may be used to reduce the load on the fabric filter, especially at high inlet

concentrations (EPA, 1998b).

Cost Information:

Cost estimates, expressed in 2002 dollars, are presented below for mechanical shaker cleaned fabric filters

and for sonic horn enhancement. Both the shaker cleaned and sonic horn cost estimates assume a

conventional design under typical operating conditions. The costs do not include auxiliary equipment such

as fans and ductwork. 

The costs for shaker cleaned systems are generated using EPA’s cost-estimating spreadsheet for fabric filters

(EPA, 1998b). The cost estimate for sonic horn enhancement is obtained from the manufacturer quote given

in the OAQPS Control Cost Manual (EPA, 1998b). Sonic horns are presented as an incremental cost to the

capital cost for a shaker cleaned system. The operational and maintenance (O&M) cost for shaker cleaned

systems are reduced by 1% to 3% with the sonic horn enhancement. 

Costs are primarily driven by the waste stream volumetric flow rate and pollutant loading. In general, a small

unit controlling a low pollutant loading will not be as cost effective as a large unit controlling a high pollutant

loading. The costs presented are for flow rates of 470 m3

/sec (1,000,000 scfm) and 1.0 m3/sec (2,000 scfm),

respectively, and a pollutant loading of 9 g/m3

 (4.0 gr/ft3) .

Pollutants that require an unusually high level of control or that require the fabric filter bags or the unit itself

to be constructed of special materials, such as Gore-Tex or stainless steel, will increase the costs of the

system (EPA, 1998b). The additional costs for controlling more complex waste streams are not reflected in

the estimates given below. For these types of systems, the capital cost could increase by as much as 30%

and the O&M cost could increase by as much as 7%.

a. Capital Cost: $17,000 to $153,000 per m3

/sec ($8 to $72 per scfm)

$1,000 to $1,300 per m3

/sec ($0.51 to $0.61 per scfm), additional cost for 

 sonic horns

b. O & M Cost: $9,300 to $51,000 per m3

/sec ($4 to $24 per scfm), annually
EPA-CICA Fact Sheet Fabric Filter

4 Mechanical Shaker Cleaned Type

c. Annualized Cost: $11,000 to $95,000 per m3

/sec ($5 to $45 per scfm), annually

d. Cost Effectiveness: $41 to $334 per metric ton ($37 to $303 per short ton)

Theory of Operation:

In a fabric filter, flue gas is passed through a tightly woven or felted fabric, causing PM in the flue gas to be

collected on the fabric by sieving and other mechanisms. Fabric filters may be in the form of sheets,

cartridges, or bags, with a number of the individual fabric filter units housed together in a group. Bags are

most common type of fabric filter. The dust cake that forms on the filter from the collected PM can significantly

increase collection efficiency. Fabric filters are frequently referred to as baghouses because the fabric is

usually configured in cylindrical bags. Bags may be 6 to 9 m (20 to 30 ft) long and 13 to 31 centimeters (cm)

(5 to 12 inches) in diameter. Groups of bags are placed in isolable compartments to allow cleaning of the

bags or replacement of some of the bags without shutting down the entire fabric filter. (STAPPA/ALAPCO,

1996)

Operating conditions are important determinants of the choice of fabric. Some fabrics (e.g., polyolefins,

nylons, acrylics, polyesters) are useful only at relatively low temperatures of 95 to 150°C (200 to 300°F). For

high-temperature flue gas streams, more thermally stable fabrics such as fiberglass, Teflon®, or Nomex® must

be used (STAPPA/ALAPCO, 1996).

Practical application of fabric filters requires the use of a large fabric area in order to avoid an unacceptable

pressure drop across the fabric. Baghouse size for a particular unit is determined by the choice of air-to-cloth

ratio, or the ratio of volumetric air flow to cloth area. The selection of air-to-cloth ratio depends on the

particulate loading and characteristics, and the cleaning method used. A high particulate loading will require

the use of a larger baghouse in order to avoid forming too heavy a dust cake, which would result in an

excessive pressure drop As an example, a baghouse for a 250 megawatt (MW ) utility boiler may have 5,000

separate bags with a total fabric area approaching 46,500 m2

 (500,000 square feet). (ICAC, 1999)

Determinants of baghouse performance include the fabric chosen, the cleaning frequency and methods, and

the particulate characteristics. Fabrics can be chosen which will intercept a greater fraction of particulate, and

some fabrics are coated with a membrane with very fine openings for enhanced removal of submicron

particulate. Such fabrics tend to be more expensive. Cleaning intensity and frequency are important variables

in determining removal efficiency. Because the dust cake can provide a significant fraction of the fine

particulate removal capability of a fabric, cleaning which is too frequent or too intense will lower the removal

efficiency. On the other hand, if removal is too infrequent or too ineffective, then the baghouse pressure drop

will become too high. (ICAC, 1999)

Mechanical shaking has been a popular cleaning method for many years because of its simplicity as well as

its effectiveness. In typical operation, dusty gas enters an inlet pipe to the shaker cleaned fabric filter and very

large particles are removed from the stream when they strike the baffle plate in the inlet duct and fall into the

hopper. The particulate-laden gas is drawn from beneath a cell plate in the floor and into the filter bags. The

gas proceeds from the inside of the bags to the outside and through the outlet pipe. The particles are

collected on the inside surface of the bags and a filter cake accumulates. In mechanical shaking units, the

tops of bags are attached to a shaker bar, which is moved briskly (usually in a horizontal direction) to clean

the bags. The shaker bars are operated by mechanical motors or by hand, in applications where cleaning is

not required frequently. (EPA, 1998a)

The vibration cleaning method is similar to mechanical shaking units. It utilizes a pneumatically driven high

frequency, low amplitude vibration of the bag frame to clean the bags. This method has limited application

due to its low cleaning energy and smaller baghouse design (Billings, 1970). 
EPA-CICA Fact Sheet Fabric Filter

5 Mechanical Shaker Cleaned Type

Sonic horns are increasingly being used to enhance the collection efficiency of mechanical shaker and

reverse-air fabric filters (AWMA, 1992). Sonic horns utilize compressed air to vibrate a metal diaphragm,

producing a low frequency sound wave from the horn bell. The number of horns required is determined by

fabric area and the number of baghouse compartments. Typically, 1 to 4 horns per compartment operating

at 150 to 200 hertz are required. Compressed air to power the horns is supplied at 275 to 620 kiloPascals

(kPa) (40 to 90 pounds per square inch gage (psig)). Sonic horns activate for approximately 10 to 30 seconds

during each cleaning cycle (Carr, 1984) .

Sonic horn cleaning significantly reduces the residual dust load on the bags. This decreases the pressure

drop across the filter fabric by 20 to 60%. It also lessens the mechanical stress on the bags, resulting in

longer operational life (Carr, 1984). As stated previously, this can decrease the O&M cost by 1 to 3%,

annually. Baghouse compartments are easily retrofitted with sonic horns. Sonic assistance is frequently used

with fabric filters at coal-burning utilities (EPA, 1998a).

Advantages:

Fabric filters in general provide high collection efficiencies on both coarse and fine (submicron) particulates.

They are relatively insensitive to fluctuations in gas stream conditions. Efficiency and pressure drop are

relatively unaffected by large changes in inlet dust loadings for continuously cleaned filters. Filter outlet air

is very clean and may be recirculated within the plant in many cases (for energy conservation). Collected

material is collected dry for subsequent processing or disposal. Corrosion and rusting of components are

usually not problems. Operation is relatively simple. Unlike electrostatic precipitators, fabric filter systems

do not require the use of high voltage, therefore, maintenance is simplified and flammable dust may be

collected with proper care. The use of selected fibrous or granular filter aids (precoating) permits the highefficiency collection of submicron smokes and gaseous contaminants. Filter collectors are available in a large

number of configurations, resulting in a range of dimensions and inlet and outlet flange locations to suit

installation requirements. (AWMA, 1992)

Disadvantages:

Temperatures much in excess of 290°C (550°F) require special refractory mineral or metallic fabrics, which

can be expensive. Certain dusts may require fabric treatments to reduce dust seepage, or in other cases,

assist in the removal of the collected dust. Concentrations of some dusts in the collector, approximately 50

g/m3

 (22 gr/ft3), may represent a fire or explosion hazard if a spark or flame is accidentally admitted. Fabrics

can burn if readily oxidizable dust is being collected. Fabric filters have relatively high maintenance

requirements (e.g., periodic bag replacement). Fabric life may be shortened at elevated temperatures and

in the presence of acid or alkaline particulate or gas constituents. They cannot be operated in moist

environments; hygroscopic materials, condensation of moisture, or tarry adhesive components may cause

crusty caking or plugging of the fabric or require special additives. Respiratory protection for maintenance

personnel may be required when replacing fabric. Medium pressure drop is required, typically in the range

of 100 to 250 mm of water column (4 to 10 inches of water column). (AWMA, 1992)

Other Considerations:

Fabric filters are useful for collecting particles with resistivities either too low or too high for collection with

electrostatic precipitators. Fabric filters therefore may be good candidates for collecting fly ash from low-sulfur

coals or fly ash containing high unburned carbon levels, which respectively have high and low resistivities, and

thus are relatively difficult to collect with electrostatic precipitators. (STAPPA/ALAPCO, 1996)
EPA-CICA Fact Sheet Fabric Filter

6 Mechanical Shaker Cleaned Type

References:

AWMA, 1992. Air & Waste Management Association, Air Pollution Engineering Manual, Van Nostrand

Reinhold, New York. 

EPA, 1998a. U.S. EPA, Office of Air Quality Planning and Standards, “Stationary Source Control

Techniques Document for Fine Particulate Matter,” EPA-452/R-97-001, Research Triangle Park, NC.,

October. 

EPA, 1998b. U.S. EPA, Office of Air Quality Planning and Standards, “OAQPS Control Cost Manual,”

Fifth Edition, Chapter 5, EPA 453/B-96-001, Research Triangle Park, NC. December. 

Billings, 1970. Billings, Charles, et al, Handbook of Fabric FIlter Technology Volume I: Fabric Filter

Systems Study, GCA Corp., Bedford MA, December.

Carr, 1984. Carr, R. C. and W. B. Smith, Fabric Filter Technology for Utility Coal-Fired Power Plants, Part

V: Development and Evaluation of Bag Cleaning Methods in Utility Baghouses, J. Air Pollution Control

Assoc., 34(5):584, May.

ICAC, 1999. Institute of Clean Air Companies internet web page www.icac.com, Control Technology

Information - Fabric Filters, page last updated January 11, 1999.

STAPPA/ALAPCO, 1996. State and Territorial Air Pollution Program Administrators and Association of

Local Air Pollution Control Officials, “Controlling Particulate Matter Under the Clean Air Act: A Menu of

Options,” July.