United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Research Triangle Park NC 27711
EPA-600/7-79-094
April 1979
Assessment of a
High-velocity Fabric
Filtration System Used
to Control Fly Ash
Emissions
Interagency
Energy/Environment
R&D Program Report
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
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9. Miscellaneous Reports
This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series. Reports in this series result from the
effort funded under the 17-agency Federal Energy/Environment Research and
Development Program. These studies relate to EPA's mission to protect the public
health and welfare from adverse effects of pollutants associated with energy sys-
tems. The goal of the Program is to assure the rapid development of domestic
energy supplies in an environmentally-compatible manner by providing the nec-
essary environmental data and control technology. Investigations include analy-
ses of the transport of energy-related pollutants and their health and ecological
effects; assessments of, and development of, control technologies for energy
systems; and integrated assessments of a wide-range of energy-related environ-
mental issues.
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This report has been reviewed by the participating Federal Agencies, and approved
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This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/7-79-094
April 1979
Assessment of a High-velocity Fabric
Filtration System Used to Control
Fly Ash Emissions
by
J.D. McKenna, J.C. Mycock,
K.D. Brandt, and J.F. Szalay
Enviro-Systems and Research, Inc.
2141 Patterson Avenue, SW
Roanoke, Virginia 24016
Contract No. 68-02-2148
Program Element No. EHE624
EPA Project Officer: J.H. Turner
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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CONTENTS
Abstract
List of Figures
List of Tables
Acknowledgements
11
iii
v
vi
Section
I
II
III
IV
V
VI
VII
VIII
IX
X
XI
XII
XIII
XIV
Title
Introduction
Conclusions
Recormendations
The Kerr Boilers
System Design and Manufacture
Description of Baghouse Details
List of System Components
Bag Candidates
Description of the Controls
Instrumentation
List of Instrumentation
Economic Consideration
Operation
Start-Up and Operating Procedures
Data Obtained
Future Plans
Appendix
Page
1
6
7
8
13
17
21
23
26
36
38
40
53
58
60
71
72
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ABSTRACT
As a follow-up to a pilot plant study, a full scale investigation of
applying high velocity fabric filtration to coal-fired boiler fly ash control
was conducted. Two filter systems were separately applied to two 60,000 lb./
hr. coal fired boilers. Performance evaluations conducted over the course
of a year included total mass removal efficiency and fractional efficiencies.
One filtration system employed Teflon felt as the filter medium while the
second system employed Gore-Tex, a PTFE laminate on PTFE woven backing.
During the course of the year a limited number of glass felt and woven glass
bags were introduced into the house containing Gore-Tex.
Installed, operating and annualized costs have been computed for five
filter media (Teflon felt, Gore-Tex PTFE laminate, 2 weights of woven glass
and a felted glass fabric) in a fabric filter system capable of handling
70,000 ACFM. The lighter weight woven glass fabric is the least expensive
filter medium overall and (assuming a four-year bag life is feasible) this
makes fabric filtration an economically attractive alternative to electro-
static precipitation.
11
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LIST OF FIGURES
Figure
Number Title Page
1 Kerr Pilot Plant 2
2 EPA Demonstration of the Enviro-Systems Fabric 4
Filter System
3 House on Truck Leaving Factory 15
4 House Being Lifted Onto Hopper - Far View 15
5 House Being Lifted Onto Hopper - Near View 16
6 Conpleted System 16
7 Top View of Module Showing Cell and Bag 18
Arrangement
8 Schematic of Bag Arrangement 24
9 Control Panel 27
10 System Schematic - House Number 1 29
11 System Schematic - House Number 2 30
12 Plan and Elevation Views of a Baghouse 31
13 Comparison of Five Filter Media for Installed 42
Costs vs. Gas-to-Cloth Ratio
14 Comparison of Five Filter Media for Operating 43
Costs vs. Gas-to-Cloth Ratio
15 The Impact of Varying Pressure Drop on Operating 45
Costs: Teflon Felt Operating Costs vs. Gas-
to-Cloth Ratio
16 The Impact of Varying Pressure Drop on Operating 46
Costs: PTFE Laminate Operating Costs vs.
Gas-to-Cloth Ratio
17 The Impact of Varying Pressure Drop on Operating 47
Costs: Felted Glass Operating Costs vs. Gas-
to Cloth Ratio
111
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LIST OF FIGURES
(continued)
Figure
Number Title
18 The Impact of Varying Pressure Drop on Operating 48
Costs: 15 Oz./Yd.2 Woven Glass Operating Costs
vs. Gas-to-Cloth Ratio
19 The Iitpact of Varying Pressure Drop on Operating 49
Costs: 22.5 Oz./Yd.2 Woven Glass Operating
Costs vs. Gas-to-Cloth Ratio
20 Conparison of Five Filter Media for Annualized 51
Costs vs. Gas-to-Cloth Ratio
21 The Effects of Bag Price Reduction on Annualized 52
Costs vs. Gas-to-Cloth Ratio for Teflon Felt
22 Conparison of the Pilot Project and the Full Scale 70
Assessment Project in Terms of Outlet Particle
Size Distribution
A-l SD-10 General Arrangement 80
A-2 Baghouse Pictorial Showing Gas Flow 81
A-3 Baghouse Pictorial Showing Gas Flow 81
A-4 Baghouse Pictorial Showing Gas Flow - Shock si
A-5 Baghouse Pictorial Shewing Gas Flow - Drag 81
IV
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LIST OF TABLES
Table
Number Title
1 Filter Media Characteristics 1
2 Parameters Monitored 36
3 Alarms and Shut-Down Functions 37
4 Installed, Operating and Annualized Costs 41
5 Inlet Characterization 61
6 Outlet Characterization 62
7 Sumnary of EPA Method 5 Outlet Data 63
8 Coal Analysis 65
9 Inlet Characterization (Particle Sizing) 67
10 Outlet Characterization by Andersen 68
Impactor (Particle Sizing)
11 Mass Emissions and Particle Size Removal 69
Efficiencies
A-l Maintenance Schedule 95
A-2 Particle Size Distribution (Microns) Fran 102
Andersen Tests - Teflon Felt -
Gas-to-Cloth Ratio 4.5-6/1
A-3 Fractional Loading (Grains/dscf) From 103
Andersen Tests - Teflon Felt -
Gas-to-Cloth Ratio 4.5-6/1
(Nozzle Wash Chatted From Stage 1)
A-4 Fractional Loading (Grains/dscf) From 104
Andersen Tests - Teflon Felt -
Gas-to-Cloth Ratio 4.5-6/1
(Nozzle Wash Included in Stage 1)
A-5 Particle Size Distribution (Microns) From 105
Andersen Tests - Gore-Tex (With Some
Woven Glass) - Gas-to-Cloth Ratio 4.5-6/1
A-6 Fractional Loading (Grains/dscf) From 105
Andersen Tests - Gore-Tex (With Some
Woven Glass) - Gas-to-Cloth Ratio 4.5-6/1
(No Nozzle Wash Recorded)
v
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ACKNOWLEDGEMENTS
This program was funded by the Environmental Protection Agency (EPA
Grant Number 68-02-2148) with FabricsAmerica as the prime contractor and
Enviro-Systems & Research, Inc. as the major sub-contractor.
The authors wish to express their deep appreciation for installation
of Gore's fabric filters and for their subsequent technical assistance to:
W. L. Gore & Associates, Inc.
Also for technical assistance, to:
E. I. duPont de Nemours & Corpany, Inc.
And for the donation of fabric filters as well as testing assistance
to:
Huyck Corporation
Enviro-Systems & Research, Inc. also wishes to thank Dr. James H.
Turner for his technical guidance and overall direction as Project Officer.
VI
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Operation during 1977 of the baghouses at Kerr Industries was not ideal.
Mechanical failures were the greatest problem, resulting in one or the other
baghouse going off-stream, sometimes for days at a time. Difficulties at the
Kerr boiler house sometimes caused shutdown of the baghouses and resulted in
the almost daily occurrence of cold start-ups. Both baghouses experienced dew
point excursions during 1977 as a result of the mechanical and boiler house
problems mentioned above. The 1977 coal miners' strike necessitated the use,
for part of the year, of poor quality coal at Kerr.
The net result of these difficulties is illustrated by the higher than
anticipated system pressure losses.
Another illustration of the impact of these difficulties, particularly the
burning of poor quality coal, is evidenced in part by the lower than normal
filtration efficiencies. However, when reviewing these data, one must take into
account the inlet grain loadings, which seemed both lower and finer than one
would normally expect.
VII
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INTRODUCTION
In 1973 Enviro-Systerns & Research, Inc. was awarded an EPA contract for
the purpose of determining the technical and economic feasibility of employing
fabric filter dust collectors for fly-ash emission control, particularly as
applied to industrial boilers. Initially, the program was jointly funded by
EPA, Kerr Finishing Division of FabricsAmerica and Enviro-Systerns & Research,
Inc. (ES&R). The plant, located in Concord, North Carolina, served as the
host site for the program, and ES&R manufactured and installed the pilot
facility. The pilot plant, installed on a slip stream of Kerr's No. 2
boiler, was sized to handle 11,000 ACFM when operating at a gas-to-cloth
ratio (apparent filtering velocity) of 6/1. This prototype facility was
actually a two module commercial size unit (Enviro-Clean Model RAC-3)
selected in order to minimize future scale-up problems. It is shown in
Figure 1.
In order to evaluate fabric filtration as an acceptable means of dust
collection with respect to coal-fired stoker boilers, the following had to
be examined:
1. Pressure drop vs. gas-to-cloth ratios for the various levels
of cleaning-air volumes and bag material types.
2. Outlet loadings by size vs. gas-to-cloth ratios for the
various levels of cleaning air volumes and bag material
types.
3. S02, 303, inlet loadings and particle size distributions.
4. Capital and operating cost comparisons for the different
bag materials vs. an electrostatic precipitator.
5. The boiler load for the various tests performed.
(R) (R)
The filter media evaluated were Noinex felt, Teflon felt (2 styles),
(R) (R)
Gore-Tex and Dralon-T . Fractional efficiencies were determined using
an Andersen inertial impactor for the four filter media at three gas-to-cloth
levels. The effect of cleaning gas volume on outlet loading and on pressure
drop across the bags was evaluated.
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Figure 1
Kerr Pilot Plant
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In addition, studies of the effect of cleaning frequency and duration
were conducted. The overall technical conclusion was that all four media
tested could achieve outlet loadings meeting state code requirements regard-
less of the gas-to-cloth ratio (apparent filtering velocity). As the gas-
to-cloth ratio increased, both the pressure drop and the outlet loadings
increased.
Installed costs were determined and operating and annualized costs were
developed from the operating characteristics obtained plus assumptions
regarding bag life. They were then compared with precipitator costs devel-
oped for tlie same site. This pilot plant program and subsequent economic
analysis led to the conclusion that fabric filter dust collectors are suit-
able for control of fly-ash from stoker fed coal-fired industrial boilers in
terms of both dust removal efficiency and operating pressure drop. The main
question left unanswered was what bag life is achievable with continuous
service. If two year bag life could be achieved, even with Teflon felt (the
most expensive bags), fabric filters appear economically more attractive
than electrostatic precipitators for industrial coal-fired boiler applications.
The pilot plant program provided short term performance data including
dust removal efficiencies and pressure drops for a number of filter media.
These data and a preliminary economic analysis indicated that long term bag
life and performance studies were warranted. The EPA thus decided to award
a contract for the full scale assessment of this approach to fly-ash control.
Figure 2 is an artist's rendition of the assessment project. The initial
contract awarded to FabricsAmerica, with ES&R as the major sub-contractor,
called for ES&R to design, fabricate, install and then operate the two
fabric filter units for a period of one year. Contract options called for
subsequent additional long term operation of the units in order to test other
filter media and also to evaluate the device as a sulfur dioxide removal
system.
The purpose of the assessment program is the testing of a full scale
fabric filter system installed on an industrial size coal-fired stoker boiler.
The baghouse system will be operated and tested over the duration of the pro-
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Figure 2
EPA DEMONSTRATION OF THE ENVIRO-SYSTEMS FABRIC FILTER SYSTEM
AT KERR FINISHING DIV FABRICS AMERICA, CONCORD, NORTH CAROLINA
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gram to determine general operating parameters, bag life data and economic
factors necessary for making techno-economic evaluations.
The objectives of the program are to demonstrate the feasibility of
applying fabric filtration to industrial size coal-fired stoker boilers and
to obtain the following data:
1. Comparisons of system performance (size efficiency and pres-
sure drop) for Noitiex, Gore-Tex, Teflon and Dralon-T fabrics.
2. Determination or prediction of fabric changes and fabric
life for each fabric.
3. Capital, operating and annualized costs for the filter
system for each fabric tested, and comparison with equiva-
lent electrostatic precipitators.
4. A record of all pertinent boiler and filter system operating
parameters.
5. Scale-up factors or deviations from the original work
performed under Contract 68-02-1093.
6. Characterization of the flue gas stream.
7. Characterization of the boiler fly-ash.
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CONCLUSIONS
"Average" outlet particle size distribution curves are roughly parallel
for the pilot plant and the full scale unit; however, the full scale unit
yielded a smaller percentage of sub-micron particles.
The outlet transmisscmeter on Baghouse No. 2 recorded little change in
opacity between normal operation and grate cleaning.
Bag failure rate in the first year indicates that bag life for both
Teflon felt and the Gore-Tex PTFE laminate could exceed the estimated four
years if the failure rate is not accelerated by on-stream time.
Of the media tested, Teflon felt is the most resistant to wear by
abrasion and acid attack. Nomex felt is the least resistant to acid attack.
The least expensive filter medium to install and operate with (assuming a
four-year bag life) is the 15 oz./yd.2 woven glass.
The Teflon felt medium is the most expensive to install. At gas-to-
cloth ratios of 3.5/1 and lower, Teflon felt is also the most expensive with
which to operate; however, at higher gas-to-cloth ratios, the PTFE laminate
is the most expensive to operate, because of higher pressure drops for this
medium.
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RBCCMyENDATIONS
Irrpactor data should be collected to prove or disprove the theory that
the multicyclone in use during the pilot plant project did indeed cause the
shift in the "average" particle size distribution curves.
In order to corroborate predicted bag life the Teflon felt medium needs
to remain on stream so that actual bag life can be determined. During this
time pressure drop versus gas-to-cloth data should be expanded and corre-
lated with on-stream time.
Finally, the lime injection system needs to be evaluated as an S02
pollutant removal system as well as an aid in reducing acid attack on filter
media.
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THE KERR BOILERS
The Kerr Finishing Division of FabricsAmerica is a textile dye and
finishing plant located in the textile belt of central North Carolina.
Kerr's normal production schedule is three shifts per day, five days
per week (although they sometimes operate six days per week) with 450-500
employees. Plant capabilities include processes to bleach, mercerize, dye,
nap, finish and Sanforize both cotton and synthetic fabrics, as well as
cutting and preparing corduroy.
Two Babcock and Wilcox Type FF integral furnace, water tube boilers
are in operation at the Kerr facilities. During the test period they have
been in use 146 hours per week and are shut down only between 11:00 PM
Saturday and 9:00 PM Sunday each weekend. The annual plant shutdowns occur
one week in July to encompass July 4th as well as three or four days sur-
rounding Christinas.
The boilers burn bituminous IV X V modified stoker coal. The average
combined coal consumption of these boilers is approximately 75 tons per day;
however, during winter months nearly 100 tons of coal are burned per day
since the plant is also heated by steam. At this time the average heat
input per boiler is 50 million BTU per hour, although its design parameter
is 73.2 million BTU per hour.
Last winter's coal strike had some effect on boiler operation at Kerr.
The company was able to purchase coal from a nearby plant that had converted
to oil burners. Although this coal was readily accessible, it was poorer in
quality than the coal ordinarily used and much of it was frozen or wet.
With the higher moisture content it is difficult to keep up the boiler load
since the excess water tends to put the fire out.
Based on specific performance conditions, the Babcock and Wilcox Company
guarantees a two-hour peaking capacity of seventy thousand pounds of steam
per hour for each boiler. The design capacity for each boiler is sixty thou-
sand pounds of steam per hour although the load range is actually twenty-five
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thousand to sixty thousand pounds per hour each. The boilers operate at
approximately forty-five thousand pounds of steam per hour each about fifty
percent of the tine. They operate at the high load thirty percent of the
tiros and the low load twenty percent of the time. Usually when one boiler
is running high the other is running low. At the design capacity of sixty
thousand pounds of steam per hour each, the boilers should have a combined
efficiency of 82% or greater, with a draft loss of less than 5.4 inches (W.G.)
through the unit and with less tlian three parts per million of solids in the
steam leaving the boiler. However, the operating efficiency is approximately
77%.
In this type of boiler the furnace gases enter one side of the boiler,
travel up the full height, make three horizontal passes and then exit through
the opposite side of the boiler. Baffles between the tube sections keep the
flow across the tubes rather than along than. "The interior of the steam
drum is so arranged that the boiler water circulates down to the lower drum
through a section of boiler tubes in the third or last gas pass of the boiler.
The water from the lower drum then circulates up through the remainer of the
boiler tubes and the tubes in the furnace walls. An additional water-cooled
wall in the furnace of the FF boiler provides an "open-pass" through which
the gases flow after leaving the furnace." (Steam, The Babcock & Wilcox
Company, 1955; pp. 11-5, 11-6)
Both boilers are right hand with lieating surfaces of 7,900 sq. ft. and
design pressures of 250 psi. The tubes are two inches in diameter (except in
the furnace walls where they are two and one-half inches) the insides of
which are cleaned by a standard turbine tube cleaner and the outsides by soot
blowers. Boiler and furnace casings were constructed of #12 gauge steel.
Each boiler is equipped with a Detroit Rotostoker consisting of a
stoker proper, which includes a four-section dumping grate having a total
active grate area of 186.1 square feet; a steam cylinder operated by a
three-way control valve; two one-horsepower motors each running two stoker
coal feeders; four hand controlled blast gates for controlling forced
draft air to each grate section; and a sectionalized front assembly with
ashpit and firing doors. The grates are cleaned at four-hour intervals
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(1:00, 5:00 and 9:00 AM; 1:00, 5:00 and 9:00 PM) and the cleaning lasts
approximately 20 minutes per boiler, or about 5 minutes per grate. Included
also is an extension coal hopper assembly to increase coal storage to 2,200
pounds. Each boiler is also equipped with a cinder return system for
returning the heavy particulate collected by the raulti-cyclones for
reburning. This system is no longer in operation since the multi-cyclones
have been gutted.
Fly ash collected in the pilot study as well as early in the full scale
operation had a high carbon content. In December, 1976, an evaluation of
the possibility of re-injecting this fly ash was made. Re-injection would
yield a dual problem of increased dust loading and increased abrasion on
this type of baffle design boiler. It was estimated that a 70% re-injection
was possible when a baghouse was used, but it would give an efficiency
improvement of only 3 or 4 percent. It is believed that this measure would
be more feasible on a modern boiler where steps could be taken to reduce
abrasion and slag build-up.
Both boilers are similarly equipped. The only difference between them
is that Unit #2 is equipped with overfire steam injection to achieve better
combustion control. The coal is put in three feet above the boiler bed,
thus there is a certain amount of suspended coal dust. The steam injection
system is merely a perforated steam pipe, through the boiler wall, which
blows the suspended coal down to the boiler bed to be burned.
The air heaters have 4,700 square feet of heating surface composed of
two-inch elements of 15 gauge steel with steel plate baffles to produce proper
heat transfer. The steam and bottom drums are 54 inches and 36 inches in
diameter, respectively, and the drum plate lias a tensile strength of 70,000
psi. The multi-cyclones were Model 9VG12 manufactured by the Western
Precipitation Corporation. They were sized to handle 35,000 CFM at 400° F
with a pressure drop across each multicyclone of 2.4 inches (water column).
The multi-cyclones were gutted before beginning the assessment project.
Each boiler was also provided with ports for three Babcock and Wilcox
register type burners to ease a fuel transition to oil or natural gas,
should there be a need.
10
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The forced draft fan is a Sturtevant #95 Turbovane, Design 9, with a
40 horsepower general purpose induction motor with special insulation to
resist abrasive dust and with a magnetic across-the-line starter. The
forced draft fan was sized to handle 17,000 CFM at 80° F. The induced
draft fan is a Sturtevant #1002 TVTD, Design 2, with a 100 horsepower
general purpose induction motor, also with the dust-resistant insulation
and with an auto-transformer reduced voltage magnetic starter. This fan
was sized to handle 33,000 CFM at 400° F.
The soot blowers are Automatic Valv-in-Head Model G-9B, manufactured
by the Diamond Power Specialty Corporation. Each boiler has tvro soot
blowers with two-inch revolving elements made of steel and "calorized"
(i.e., heavy seamless steel "calorized" inside and out by impregnating the
steel surface with aluminum, thus making it very refractory to high gas
temperatures). The air heaters each have one straight line unit. Scot
blower operating pressure is 150 pounds. The furnace draft is increased
for soot blowing and the air and fuel are manually controlled.
Each boiler is equipped with Bailey meters. The boiler meter (Type
D36) indicates and records steam flow and records air flow supplied to the
furnace for combustion. The temperature recorder (Type K35, Class 5H5H5H)
indicates and records gas temperature entering and leaving the air heater
as well as air leaving the air heater. The boiler drum water level
recorder Type LU35, Class 1) has high and low water level alarm and indi-
cating lights.
According to the Baboock and Wilcox Company's proposal, the control
equipment was arranged " to control the fuel supply and the position
of the induced draft damper simultaneously and in parallel as required to
meet the demand for steam as indicated by changes in steam pressure at the
boiler outlet. Optimum combustion conditions will be automatically main-
tained at all times by readjusting the position of the induced draft
damper as required to maintain the steam flow and air flow records of the
boiler in coincidence. Furnace draft will be maintained automatically by
positioning the forced draft damper."
11
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The feedwater control is "two-element and air-actuated, receiving a
primary load change impulse from the boiler steam flow recorded with final
repositioning impulse from the boiler drum level".
The air compressor is a "two stage, air cooled, motor drive, hori-
zontal receiver mounted design".
Each stack is 75 feet from floor level and 48 inches in diameter. The
steel stacks were supplied as seven stages plus a flare and with an expan-
sion joint between the induced draft fan and the stack.
12
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SYSTEM DESIGN AM3 tBVHUFACTURE
Before the full scale system could be completely designed, the location
for the collectors had to be determined. The objectives were to maximize
the use of the space available and to determine the length of duct to the
collectors. The final decision was to parallel the baghouses at the end of
the property near the boiler house. This location isolated the units from
plant traffic and minimized the loss of parking space. The control room
was then placed adjacent to the baghouses for easy access. Also considered
in this orientation was the possible future location of lime injection
equipment for sulfur dioxide removal.
The baghouse foundations were designed as spread footings at the orig-
inal grade. The structural support system was designed as column and beam
construction with a cantilever section to support the testing platform at
the collector discharge end. A "penthouse" over both baghouses was built
to protect workers during bag changes and testing. The penthouse has solid
metal sides with several translucent roof panels for light and fans for
ventilation. All levels have stair access for testing and maintenance.
Prior to operation of tlie baghouses certain measures had to be taken to
insure its success. The existing multi-cyclones were gutted because they
provided little ash removal and because the tubes were in poor condition.
Also a boiler stack damper had to be designed since the baghouse inlet
ductwork opened into the existing stacks. The stacks could not support
heavy top caps, so a butterfly-type was designed, and positioned above the
duct take-off to the collector. This location of the cap facilitates
servicing and cap position monitoring from the roof of the boiler house.
An interlock was built into the boiler start-up circuits to prevent
starting if the stack dampers are closed.
The baghouses are identical to facilitate interchangeability of parts.
The air compressors are interconnected to provide back-up capability. The
inlet duct lengths were designed so that test ports could be located 8 duct
diameters downstream and 2 duct diameters upstream from any flow disturbance,
and the inlet ducts measure 36" X 36". This facilitates testing by requiring
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only 12 traverse points in the duct according to the Code of Federal Regu-
lations (Title 40, Part 60, Appendix A). The testing platform at the inlet
ducts was extended to the boiler house roof to provide easy access. Adjust-
able inlet distribution dampers have been provided as a means to equalize
distribution of tlie dust loading to all hoppers and chambers.
Pyramid hoppers with double dump valves were selected over trough hop-
pers with screw conveyors. This choice was made in order to eliminate the
potential abrasion and wear problems that fly ash conveying via screw
conveyors pose. During manufacture of the hoppers and double dump valves,
provisions were made for capacitance type hopper level indicators. The
ash is currently delivered from the double dump valves through elephant
trunk tubes to bins supplied by Kerr Finishing.
The fan stacks were set at a height equal to the existing boiler stacks
in order to provide the same 12 point sampling traverse criteria as out-
lined for the inlet ductwork. The outlet duct inside area is 11.396 square
feet. The stacks are set for vertical discharge and have a rain lip at the
top for drawing off water. The stacks have expansion-isolator joints and
are supported by the penthouse floor.
Figures 3 through 6 show steps in the erection of the baghouses and
the completed structure.
14
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Figure 3
House on Truck Leaving Factory
Figure 4
House Being Lifted onto Hopper - Far View
15
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Figure 5
House Being Lifted onto Hopper - Near View
Figure 6
Completed System
16
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DESCRIPTION OF BAGHOUSE DETAILS
Before the dust collector design could be finalized, certain criteria
had to be examined. Ite collector would have to remove fly ash at a concen-
tration of 0.6 grains/cubic foot (80% of which was smaller than 10 microns
in diameter). The total flue gas design volume to be handled was 70,000
ACFM at 400° F with a moisture content of 8% by volume. The baghouse system
would be in continuous operation outdoors at an elevation of 700 feet above
sea level. Maximum design pressure drop across the total system was 12
inches of water.
Two Enviro-Clean Model 648--RAC3-5-104 fabric filter dust collectors
were selected for the assessment project each to handle the flue gas from
one boiler. The operating pressure drop should range from 2-7" W.G. and the
maximum operating temperature is 450° F. Figures for the SD-10 general
arrangement and for the baghouse gas flow can be found in Appendix A-2.
Each single chamber baghouse consists of 18 cells with thirty-six bags
per cell, or 648 bags per house. The bags are five inches in diameter and
eight feet - eight inches in length, yielding a total fabric area of 7,440
square feet per baghouse. This produces a gas-to-cloth ratio of 4.71 to 1
with all cells active, or 4.98 to 1 with one cell cleaning. Cleaning cycles
are automatically set by a timer but are adjustable.
The bags are set into a tube sheet (as seen in Figure 7), located
6 3/4" to 4 3/4" from the sloped top of the house. Two snap rings are
incorporated into the open end of each bag and when the bag is in place
one ring is above and one below the tube sheet. Each bag also slips into
a grid of metal prongs at the bottom of each cell to prevent bag-bag and
wall-bag abrasion. On a horizontal plane, spacing between the bags at the
tube sheet is 6 3/8 inches from the center of one bag to the center of the
next in one direction and 6*5 inches perpendicular to the first direction.
Rigid cages 5 inches in diameter with 10 vertical supports are set
inside the bags to prevent them from collapsing. The cages were constructed
of 9 gauge mild steel and were electrolytically plated with nickel to a
thickness of 3 mils, the nickel plating was then coated by a chrome flashing
17
-------
ooooo
f oooool
.00000
ooooo1
JQOOO
Figure 7
Top View of Module Showing Cell and Bag Arrangement
18
-------
to a thickness of 1 mil. Before this type of cage was chosen, both a wire
mesh and a spiral cage were considered. The spiral cage was eliminated
because of its potential for creating abrasion between the bags and the
house walls. The wire mesh was eliminated because it was unproven. The
nickel-chrome coating over mild steel was used in an attempt to reduce
corrosion.
The baghouses are constructed of 10 gauge mild steel with 3" 1" by
3' 4" hatch covers over each cell. The hatch covers are hinged to provide
easy access for checking and replacing bags. Each baghouse has three
pyramid hoppers with side-wall slopes of 60°. Tne hoppers are made of
3/16" mild steel and have a capacity of approximately 363 ft. each, or
1,089 ft. per house. The hoppers can be emptied either automatically or
manually through the "double-dump" valve at the bottom of each hopper.
The double-dump valve consists of two chambers, each with a volume of
approximately 1 ft. , with a gate opening from the hopper into the upper
chamber and a gate opening between the chambers. The purpose of the valve
is to eliminate a back-draft into the hopper because of its negative pres-
sure. The upper chamber is filled, closed off and then the ash dropped
into the lower chamber where it exits via elephant trunk tube into a
barrel. The long straight ductwork between boilers and baghouses is
constructed of 3/16" mild steel plate. Ductwork, baghouses and hoppers
are covered by three inches of high temperature Fiberglas insulation which
in turn is covered by a 20 gauge aluminum skin.
Other components for each baghouse (a list of system components follows
this section) include a standard cleaning timer panel, high temperature
cutoff switch, a cleaning assembly (blower) and manual slide gates, as well
as platforms, handrails and caged ladders. Auxiliary components include:
1. A fan with V-belt drive and motor rated at 150 H.P. for
35,000 ACFM at 440° F and 12" S.P. for each house.
2. A system drives panel containing cleaning fan motor
starters (reduced voltage automatic type) and a 3 KVA
transformer.
19
-------
3. Dampers that are ranotely operated to open on a temperature
set-point or upon shutdown of baghouse. Slide dampers were
provided in each stack duct take-off to isolate the bag-
houses. A signal sent by a Nineties Series 11SAD4 single
solenoid (spring return) activates an Advance Automation
Company Triple A cylinder (with two Nuflo valves each) to
slowly open or close the damper in question.
4. A temperature control system in which inlet temperature
probes are set at 440° F. If this point is reached, the
sensor will be interlocked to open the relief cap first,
followed in order by the system fan motor shutdown and then
the cleaning fan motor shutdown.
The two baghouses were covered by a "penthouse" to enable testing in
inclement weather. A system control console located under the penthouse
houses individual cleaning fan motor ampere read-outs, system fan motor
readouts, inlet duct gas temperature read-outs and individual collector
pressure drop read-outs.
20
-------
List of System Components
1. Garden City #AAKT-18-6 Fan with upblast'discharge, maximum reconmended
speed of 1800 rpm at 600° F.
2. Garden City Vortex Damper. A pressure transmitter (PI) in the boiler
stack sends an electric signal to a control unit on the control console.
This control unit maintains a constant pressure by supplying a nodulated
air supply to the vortex damper control.
3. Lincoln Motor, 150 H.P., full load speed 1780 rpm, full load current 342
amps.
4. Ingersoll-Rand Type 30 Air Compressor, Model T305TM. The Model T305TM
is a 5 horsepower compressor with a receiver capacity of 60 gallon with
maximum receiver and discharge pressure of 200 psig.
5. Eclipse Burner No. 300 H.P. This burner provides a heat capacity of
3,000,000 BTU/Hr. and requires a 1/3 horsepower blower.
6. Advance Automation Air/Hydraulic-Lav Pressure Cylinder
Model B960 3.5 Inch Bore 12 Inch Stroke
Model BS2121P1 2.5 Inch Bore 4 Inch Stroke
Model BS2123P1 1.25 Inch Bore 4 Inch Stroke
7. Lincoln Motor, 15 H.P., full load speed 1175 rpm, full load current A7 amps.
8. Advance Automation Actuator/Positioner Air Cylinder, Model B960, 3.5
inch bore, 16 inch stroke.
9. Arrow Model A-30 Non-Cycling Refrigerated Air Dryer.
10. Arrow Model 3104 Air Filter.
11. Arrow Model 1584 Air Regulator.
12. Arrow "Oilescer" Filter, Model 3304P with automatic drain.
13. Stack Cap, single blade, butterfly type, 48 3/8" inside flange diameter.
14. Purge Damper, single blade, butterfly type, 20" X 7" inside flange.
21
-------
15. Clean Air Stack Danper, louvered type, parallel blade, 6 blades, 2' 6.75"
X 4' 6.75" inside flange.
16. Bleed-In Damper, single blade, butterfly type, 6" X 36" inside flange.
17. Isolation Danper, louvered type, parallel blades, 4 blades, 36.5" X
36.5" inside flange.
22
-------
BAG CANDIDATES
The fabrics initially considered for use in the demonstration project
were those used in the pilot project - Teflon felt Style 2663, a tetra-
(R)
fluoroethylene (TFC) fluoro-carbon; Gore-Tex , an expanded Teflon (Poly-
tetrafluoroethylene - PTFE) with interfacing air filled pores; Dralon-T
i-a\
felt, a homopolymer of 100% acrylonitrile; and Noraexv"y felt, a high temper-
ature resistant nylon fiber (polyamide). Of these media, the Teflon felt
and tlie Gore-Tex PTFE laminate were selected as the first to be tested for
bag life studies.
Dralon-T was not included initially because of the maximum temperature
limitation of approximately 280° F. It is, however, still under considera-
tion. Modification of the system to cool the flue gas at the baghouse
inlet could bring satisfactory results with Dralon-T.
Nomex felt was also omitted from the first testing due to fabric degra-
dation resulting from acid attack observed during the pilot program, tfowever,
it is still under consideration since a lime coating on the fabric might
decrease the intensity of acid attack. Therefore, a useful study could be
made of treated and untreated bags with respect to on-stream time.
Currently, Baghouse No. 2 contains one full cell of Huyck experimental
felted glass bags and one cell each of Globe Albany 22% oz. woven glass
bags and Globe Albany 15 oz. woven glass bags (both with the Q-78 finish).
Also, there are three Nbmex bags in Baghouse No. 2. Locations of these
bags can be seen in Figure 8. These bags are being screened as possible
alternatives to the Gore-Tex bags in Bagtouse No. 2. Specifications for
these fabrics are listed in Table 1.
23
-------
Figure 8
Schenatic of Bag Arrangement
Si rip R
Baghouse 1
Teflon Felt
Side A
1
I
2
2
3
3
456
4 5 6
7 8
_ Cleaning Air Flow
7 8
9
9
NJ
Side A
Baghouse 2
PTFE Lamiante
Where not
marked other-
wise.
Side B
n
i
N
1
= Nomex
G
lobe Albany
22.5 Oz./YcF
36 Bags
2
Felt
2
3
3
L
i
\
N
Globe Albanv
,15 oz./Yd.2
36 Bags
5
5
4 Huvck t
36 Bags
6
6
7 8
Cleaning Air Flow
7 8
H
9
9
-------
Table 1
Ul
Filter Media
Teflon(R) Felt
Style 2663
Gore-Tex( PTFE
Laminate
Weight ~
Ozs./Yd.
21-29
4-5 +
Filter Media Characteristics
Mullen Tensile
Permeability Burst Strength
CFM/Sq. Ft. psi Lb./Inc. Min.
15-45 250 180 X 150
8-15 239-400
Cost
Per Bag
(12/77)
$ 53
45
(R)
Globe Albany
Woven Glass
Type Q78-S1611
Globe Albany
Woven Glass
Q78 Finish
(R)
Huyck - Experimental
Needled Fabric
15
22.5
29 + 2
42
25
40 + 10
700
800 +
350
630 X 360
500 X 300
14.61
18.65
21.50*
Dralon(R)-T
(D\
Nonexv ' Felt
13-15
14
20-30
25-35
250
450
131 X 100
*Based on Quote of $14.25/Yd.2
-------
DESCRIPTION OF THE CONTROLS
The elaborate control system at Kerr was designed to facilitate
testing and to facilitate the solution of any problem that might arise.
Tlie system is arranged so that the entire operation of both baghouses is
controlled from the console located in the control house adjacent to the
baghouses. When set-up for automatic operation, either baghouse can be
started and stopped from controls located in the boiler house; however,
provision is made on the control house console to lock-out the boiler
house start function.
Also located in the control liouse are the circuit breakers and starters
for the various motors, the main power disconnects, the system logic
control panels, and the distribution circuit breaker panel for 110 and 220
volt utility circuits (lighting and convenience outlets are located in the
baghouse area).
located at required locations external to the control house are posi-
tion indicating limit switches, pressure and temperature transducers,
thermocouples, burner controls for heating flue gas and air entering the
baghouse, and sequence controllers for the bag-cleaning function. A power
safety switch disconnect is located adjacent to each drive motor.
The console (Figure 9) is arranged in three parts with test instru-
mentation located in the center and the baghouse controls at the left and
right. Each baghouse console is arranged with a system diagram with status
lights located in the middle (vertical section), and all operating controls
(push buttons, indicating lights, and selector switches) on the lower or
desk section.
The control console selector switch allows baghouse operation to be
fully automatic, manual, or in testing mode. When switched to the "off"
position all control power will be disconnected leaving only the "power
available" indicating lights "on".
In the automatic mode the system is started or stopped by pressing
one "start" or one "stop" pushbutton. Damper and thermostat locations
-------
Figure 9
Control Panel
21
-------
can be found in Figures 10 and 11. A plan view (Figure 12) is also
included for reference. Upon starting the system, the preheat operation is
initiated. At this time the baghouse is isolated from the stack by closing
D3 and opening relief cap D6 to allow escape of the flue gas through the
stack. Dampers Dl (the bleed air damper) and D2 (the vortex danper) are
fully opened and the exhaust danper D4 is closed. This allows ambient air
to enter and be heated by the flame heater before passing through the bag-
house and the i/ortex damper to the cleaning fan and then exhausted to the
atmosphere through purge dampers D5A and D5B.
During the preheat node only, the cleaning fan and the heater will be
in operation. The temperature of the air is controlled by means of a ther-
mostat at T2 (baghouse inlet) which controls the heater flame by controlling
the heater gas valve. When the desired preheat temperature of 250° is
reached, or when the temperature T4 at the exhaust stack reaches 180° F, the
control system automatically will initiate the normal operating condition.
The equipment will operate in the following sequence when changing from
preheat to normal operation.
A. Open D4 (Exhaust Stack Damper)
B. Close D5A, Open D5B (Adapt-A-Clean and Purge Outlet Dampers)
C. Start Bag Cleaning System
D. Open D3 (Baghouse Isolation Damper at Kerr Stack)
E. Close Dl (Ambient Air Inlet Damper)
F. Set D2 Control on Automatic
G. Start System Fan
H. Close Relief Cap D6
During normal operation the flue gas will be passed through the baghouse
by opening dampers D3 (baghouse inlet), D2 (vortex), D4 (baghouse exhaust),
running the system and cleaning fans, and closing purge outlet damper D5A
and D5B and stack relief cap D6. A pneumatic pressure controller located
on the console maintains a set static pressure at the stack inlet by control-
ling the position of the vortex damper (D2); thus, air volume through the
house is controlled. Air temperature through the baghouse is controlled by
the inlet temperature thermostat at T2 at 250° + 10° F. If the temperature
28
-------
NJ
VD
51AC< GAMPCR
{win/tt^)
I BOILER
' STACK.
DUCT UEATER
« BLEED AIR DAMPER o-i
rnvr
I :i/V
irca i rnn IITI i
INLET DAMPER
TC# = Thermocouple - Tenperature Recorder
TW = Tracor-Westronics Thenrocouple
TIC = Teirperature Indicator - Controller
IT = Tenperature Alarm (BH £1)
ENVIRO SYSTEMS-FABRIC FILTER/ COM. FIRED BOILER
KERR INDUSTRIES -EPA PROJECT
Figure 10
System Schematic
VDRTCX DAMPER D 2 '
-------
TO ATM03FMUU
CO
o
_-. ~
" *"" -
I
I _
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BOILER
STACK
MOUSE
N» 2
^
TRMJ&MltV ITC3I
^ STACK DAMPER D-fc /
X^ (ULIl/ CW)
DUCT WtJkTER
« bLIED JklH DAMPER D- t
; \t/\\ rfrn rrrci fTrn .
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puflTi* Q**-pi» °«^« 1 ^
ANNU&AR ° .1 ^
fD (tS
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TC# - Thermocouple - Tenperature Recorder
TW = Tracor-Westronics Thermocouple
X
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RCVIM!
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ES«R ~~-~~^.^ (MRC.E
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H" aj" m» ^~^~
\ } 1
©
\ EfD /\ Effl /\ Sad /
\T / \ * / \ " /
(Reference #'s in Baghouse) \ / \ / \ /
TIC = Tenperature Indicator - Controller \_/ \_/ \y
2T = Tenperature Alarm (BH #2)
a a a
U«
HT = Hopper Tenperature ENV,RO SVSTEMS-FABR.C F.LTER/COM. HRF.D BOILER °'"«"« ^ " /
MERR INDUSTRIES - EPA PROJECT
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^
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TP
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TIMUT »»F)
(US
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TP . TCST PORT
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Figure 11
System Schematic
VORTfX OAMPCR O 2
-------
DUCT HEATER
SURNER"
BLEED A.IR
CAMprn D-I
K.
E1S*R
FABRIC FILTER
;
IWLET DAMPER 0-3
PLAN VIEW
BOILER
STACK
U)
ENVIRO SYSTEMS-FABRIC FILTER/COAL FIRED BOILER
KERR INDUSTRIES - EPA PROJECT
TO
STACK DAMPER D-4
REVERSE AIR DAMPER
DVA
PURGE DAMPER OSB
Elevation
Figure 12
In the plan view of the baghouse system, the distance
between the inlet daitper and bleed-air daitper is
different on the two houses.
VORTEX DAMPER
01
10 FAM
-------
drops below 250° F, the heater system is activated, if the temperature rises
above 380° F, ambient air is admitted to the system by opening damper Dl
and shutting off the heater.
System shutdown will be initiated by any of the following conditions:
A. Pressing any "stop" pushbutton
B. Temperature at T2 (Baghouse Inlet) exceeds 425° F
C. Boiler shutdown (initiated by "stop" pushbutton in boiler house)
D. Failure of either fan
E. Power failure
F. Control power failure
For any of the above conditions the relief cap D6 will be tripped and
thus will open automatically. As soon as 06^ is fully opened (limit switch
check) and provided E or F has not occurred, the following shutdown sequence
will be started:
A. Open Dl
B. Activate heater control
C. Open vortex D2 fully
D. Close D3
E. Open D5
F. Close D4
G. Stop system air fan - drop out normal operation relay MR
H. Start purge and purge timer; the purge cycle has the same system
set-up as "preheat" except that tlie heater will not come on
unless temperature drops below 250° F during the 1% hour purge
cycle.
I. After set time - stop purge
J. Drop out automatic system, start-up relay "AR"
K. Stop cleaning fan
During shutdown sequence a light will flash on trouble annunciator
panel and an alarm will sound. The alarm panel will also indicate the
reason for the shutdown. Note; Alarm may be shut-off by pressing "silence"
pushbutton but light will remain on until circuit causing the alarm is reset.
By switching the selector to "man" each separate operating mode will
be started and stopped manually. Interlocking will be provided, however, to
32
-------
prevent a wrong starting or shutdown sequence and all protective devices and
circuits will be functioning. Once started, the particular mode will operate
automatically as previously described under automatic operation.
Three different sets of "start-stop" pushbuttons will be activated by
the "man" position of the selector switch and indicating lights will give
the status. The following modes can be thus started:
A. Preheat
B. Normal
C. Purge
Operation will be as follows:
Pressing the preheat "start" pushbutton will initiate the previously
described preheat mode. When the set temperature of 250° F is reached an
indicating light will light and a permissive interlock will close enabling
the normal "start" pushbutton. The operator may then press the normal
"start" pushbutton and the previously described normal mode will proceed.
If any of the system shutdown signals occur the automatic shutdown sequence
will occur automatically. However, since both the preheat and normal nodes
may be stopped at any time by the operator, he may also start and stop the
purge mode at any time normal operation has ceased. The purge mode will
continue until the operator shuts down except where automatic shutdown may
occur.
With the selector switch in "test" position each electric drive motor
and each damper for all system components may be operated by a spring return
selector switch. This feature provides for checking out all equipment before
starting the baghouse or after emergency shutdowns, etc. No system inter-
locking will be active; however, protective functions such as overloads,
heater protective devices, circuit breakers and excessive temperature func-
tions will be active.
The following equipment operates regardless of the various operations
previously described.
A. Air compressors operate to maintain control air pressure but can
be started and stopped at the console. However, the entire system
33
-------
cannot function if control air pressure is too low. The air dryer
must be started before either air compressor can be started.
B. The trouble annunciators will be energized at all times.
C. By means of a "man-auto" selector switch, the bag cleaning
sequencing control may be operated manually (selector in
"man") even though the rest of the system is not operating.
When in the "auto" position, it will be started during the
automatic sequences previously described.
D. By opening the control circuit breaker (in the enclosed control
house area), all equipment will be de-energized (except the
burner blower motor).
The inlet gas heating control consists of an RTD element located at
T2 and a control unit (on the control house console) with read-out, temp- .
erature setting, high-low alarm contacts and a pneumatic output, as well
as a pneumatically operated gas volume at the heater. The gas will shut
off at the desired temperature setting (or above) and is modulated by a
controller to maintain set temperature.
A constant set pressure at PI is maintained by controlling the vortex
damper D2 on the system fan. A pressure transnitter Pi supplies an electric
signal (4-20 mA) to a control unit located on the control console in the
control house. The control unit maintains a set pressure at PI by supplying
a modulated air supply to the D2 (vortex) pneumatic damper control. Exces-
sive pressure at Pi will be alarmed and will cause system shutdown.
34
-------
INSTRlMEMiATION
Many parameters related to the operation of the baghouses are moni-
tored and/or recorded. These include boiler stack pressure, baghouse flow
rates, pressure drops and temperatures as well as fan current, speed, etc.
Table 2 is a listing of these parameters. Note that only Baghouse No. 2
is equipped with transmissometers to record inlet and outlet opacities.
Certain functions are alarmed on the annunciator. Alarm conditions
will cause horns (located in penthouse and boiler house) and a buzzer in
the control house to sound and the particular alarm light to flash. Pres-
sing the "acknowledge" pushbutton will silence horns and buzzer and stop
flashing of the light; however, the light will remain on until the alarm
condition has been corrected or reset. Seme alarm functions will also
cause a system shutdown. The alarmed functions are listed in Table 3.
A key operated selector switch is provided so that audible alarms may be
turned off when the equipment is being checked or adjusted.
A listing of the instrumentation at the facility is located at the
end of this section. Also, location of all pressure and temperature
sensors can be found in Figures 10 and 11 for Baghouses 1 and 2,
respectively.
35
-------
Table 2
Parameters Monitored
Paraineter Measured Recorded
Boiler Stack Pressure X X
Baghouse Inlet Flow X
Baghouse Pressure Drop X
Baghouse Main Fan Pressure Drop X
Baghouse Outlet Flow X
Boiler Stack Temperature X
Baghouse Inlet Temperature X X
Baghouse Outlet Temperature X
Baghouse Cleanirig Air Temperature x
Baghouse Inlet Opacity* X
Baghouse Outlet Opacity* X
Cleaning Air Fan Static Pressure X
Cleaning Air Fan Current X
Main Fan Speed X
Main Fan Current X
System Voltage X
Baghouse Temperatures X
*Baghouse No. 2 Only
36
-------
Table 3
Alarms and Shut-Down Functions
Alarm &
Function Alarm Only Shut-Down
Bag Cleaning on Manual X
Boiler House Stop X
Control House Stop X
System Fan Below 1400 RPM X
Cleaning Air Fan Off X
Hopper Full X
Heater Off X
Pneumatic Air Low X
Stack Pressure Out of Range X
Pliase Monitor Tripped X
Inlet or Outlet Temperature High x
Dryer Off X
Alarm Horns Off X
37
-------
List Of Instrunentation
1. Taylor Electronic Differential Pressure Transmitter No. 1301T
This is a force balance instrument transmitting 4-20 mA signals
proportioned to the differential produced by the primary element.
The transmitter provides capability for measuring differential spans
from 1 to 10 inches of v/ater at operating pressures as high as 50
PSIG.
2. Taylor Electronic Differential Pressure Transmitter No. 1302T
This instrument is identical to the 1301T except it is adjust-
able from 5 to 50 inches of water and has a maximum working pressure
of 500 PSIG.
3. Taylor Pneumatic Indicating Controller No. 441R
The Taylor 441R controller is a single duty pneumatic indicating
controller with proportional response and differential gas feature.
The instrument requires an air supply pressure between 18 & 30 PSIG
with 20 PSIG being recommended. The output is a nominal 3 to 15 PSIG
signal.
4. Taylor Alarm No. 1016N
The 1016N alarm is a solid state instrument which accepts a
current or voltage input signal and provide relay contacts for oper-
ating external devices.
5. Taylor Alarm No. 1019N
The 1019N alarm is a solid state instrument which accepts a
thermocouple or millivolt input signal and provides relay contacts
for operating external devices. The relay within the alarm is de-
energized when an alarm condition exists or when power fails.
6. Taylor 2140J Series Multi-Scan Recorder
This is a potentiometric instrument which applies the princ-
iple of measuring by opposition. It is basically a D.C. voltage
meter which operates as well with current and resistance, depending
38
-------
List of Instrumentation (Continued)
on voltage. The unit can accept up to six different functions.
7. Model 400-0000 High Performance Transmissotieter manufactured by
Contraves Goerz Corporation.
8. Model 401-0000 Process Control Transmissometer manufactured by
Contraves Goerz Corporation.
9. Model ES-MS401C Recorder with felt tip cartridge pen and chart
speed of 3 cm/hr. manufactured by Esterline Angus Instrument
Corporation.
10. Taylor Industrial Thermocouple No. 81CT14 iron-constantan type.
11. Taylor Resistance Thermocouple device with 100 ohm platinum bulb.
12. Annubar No. 741-316
The annubar is an annular averaging velocity head sensor
for the natural measurement of flow through a duct. It produces
a differential pressure proportional to the square of the fluid
velocity. Manufactured by Dieterich Standard Corporation.
39
-------
ECONOMIC CONSIDERATIONS
Installed, annual operating and annualized costs have been computed for
the Teflon felt and PTFE laminate filter madia already in use at Kerr, and also
for an experimental felted glass fabric and two weights (15 oz./yd.2 and 22.5
oz./yd.2) of woven glass fabric that are being considered. Table 4 lists these
costs.
Installed costs and total cost of flange-to-flange hardware plus bags plus
installation (installation costs are based on in-house estimates), were deter-
mined for a fabric filter dust collector sized to handle 70,000 ACFM at 350° F.
The bag costs are based on January, 1978 quotes. The hardware and installation
are 1975 prices for RAC-3 model collectors similar (although different in size)
to those at Kerr. A listing of equipment included in these prices as well as
a bill of materials listing actual costs can be found in Appendix A-3. ES&R
no longer manufactures the RAC collectors but 1978 costs for the comparable
SD-10 units can be obtained by applying a multiplier of 1.7 to 1975 RAC costs.
Electrostatic precipitator costs for 1978 are also located in Appendix A-3.
Since the conclusion of the pilot study the price of the Teflon felt bags
has been reduced from $75/bag to $53/bag. This price lowering has increased
competition among fabric types. For gas-to-cloth ratios of 2.9/1, 5.8/1,
8.9/1 and 11.3/1, the installed costs for Teflon felt are $4.07, $3.79, $1.72
and $1.53 per ACFM. This cost is still somewhat higher than that of the PTFFE
lamiante, but the Teflon felt has been proven to damage less easily and, thus,
may last longer. The experimental felted glass and both fabric weights of
the woven glass are similar with respect to installed costs, and the 15 oz./
yd.2 woven glass has an installed cost of $2.89, $1.60, $1.33 and $1.22 for
gas-to-cloth ratios of 2.9/1, 5.8/1, 8.9/1 and 11.3/1 respectively. The
difference in installed costs between the most expensive and least expensive
fabrics decreases markedly as the gas-to-cloth ratio increases (see Figure
13). This is due to the decreasing percentage of capital costs attributable
to the fabric filters.
Figure 14 is a comparison of the five filter media for annual operating
costs. A sample calculation of operating and annualized costs is located in
40
-------
Table 4
Installed, Operating and Annualized Costs*
G/C Ratio
(" W.G.)
Filter Media
Teflon Felt
($53/Bag)
Gore-Tex/Gore-Tex
($45/Bag)
Globe Albany3
Vfoven Glass - 15
($14.61/Bag)
Globe Albany
Wbven Glass - 22.5 Oz./Yd.
($18,65/Bag)
Huyck Felted Glass
($21.50/Bag)
T'lange-to-flange costs are based on cost of ES&R's RAC collectors installed at Kerr in 1975, plus 1975
engineering installation estimates; bag prices and operating costs are based on prices effective 1/78.
2pressure drops are actuals obtained in the pilot study (plus 2" for the drop across the inlet duct) and
were used in the pilot study calculations.
3A multiplier of 1.7 applied to 1975 installed costs will give 1978 installed costs.
41977 mean G/C ratios and Ap's obtained in the assessment project at Kerr for Teflon felt and Gore-Tex
houses.
^Pressure drops are assumed to be equal to those of Teflon felt.
2.9/1
5.8
8.9
11.3
6 (Approx.)
2.9
5.8
8.9
11.3
6 (Approx. )
2.9
5.8
8.9
11.3
2.9
5.8
8.9
11.3
2.9
5.8
8.9
11.3
2.5
3.4
5.9
9.2
7.14
4.2
5.3
8.9
11.4
12. 24
2.5
3.4
5.9
9.2
2.5
3.4
5.9
9.2
2.5
3.4
5.9
9.2
1975
Installed
Costs3
$ 285,080
153,700
120,570
107,318
153,700
267,800
145,060
114,810
102,710
145,060
202,158
112,239
92,929
85,205
210,884
116,602
95,838
87,532
217,040
119,680
97,890
89,174
1977
Operating
Costs
$ 33,100
20,410
20,120
24,130
27,050
31,833
21,656
24,063
26,210
34,030
12,273
10,042
13,212
18,605
14,555
11,134
13,940
19,187
16,094
11,903
14,453
19,597
1977
Annualized
Costs
$ 71,016
40,852
36,156
38,403
47,492
67,450
40,949
39,333
39,870
53,323
39,260
24,970
25,572
29,937
42,603
26,642
26,686
30,829
44,960
27,820
27,472
31,457
-------
II
a
CO
o
H
I
CO
10
8
8
in
300
200
100
Figure 13
Comparison of Five Filter Media for Installed Costs
vs.
Gas-to-Cloth Ratio
KEY;
O Teflon Felt ($53/Bag)
A Gore-Tex PTFE Laminate ($45/BRg)
(~\ Huyck Experimental Felted Glass
($21.50/Bag)
Globe Albany 22.5 Oz. woven Glass
($18.65/Bag)
D Globe Albany 15 Oz. Woven Glass
($!4.61/Bag)
4 6 8 10 12
Gas-to-Cloth Ratio (ACFM/Ft.2)
A multiplier of 1.7 applied to these 1975 installation costs will give
1978 installation costs.
42
-------
Figure 14
Comparison of Five Filter Media for Annual Operating Costs
- _____
Gas-to-Cloth Patio
35..
30
en
a
TD 25
20
15
10
KEY:
O Teflon Felt
A Gore-Tex PTFE Laminate
O Huyck Experimental Felted Glass
Globe Albany 22.5 Oz. Woven Glass
Globe Albany 15. Oz. Woven Glass
j_
J_
6 8
Gas-to-Cloth Ratio
10
12
43
-------
Appendix A-3. The following assumptions were made in order to compute these
values:
1. Bag replacement would be 25% per year.
2. Operating pressure drops would be the same as those determined
in the pilot study for Teflon felt and PTFE laminate, since
the pilot study dealt with a wider range of gas-to-cloth
ratios than the assessment project has thus far. (However,
for comparison, Table 4 shows actual 1977 mean operating
G/C ratios and Ap's for both baghouses, and their effect
on operating and annualized costs.)
3. The pressure drops for woven glass bags and felted glass
bags would be the same as those for Teflon felt.
4. Current average electrical rates were $0.021/KWH.
5. Based on operation of 6,240 hours/year.
From the graph it is obvious that the 15 oz./yd. woven glass bags have
the lowest operating cost assuming that the pressure drops used in the
computations are nearly correct. Operating costs for these bags are $0.18,
$0.14, $0.19 and $0.27 per ACFM for gas-to-cloth ratios of 2.9/1, 5.8/1,
8.9/1 and 11.3/1. With the lowered Teflon felt bag price, Teflon felt has a
lower operating cost than the PTFE laminate for gas-to-cloth ratios higher
than 4/1. This is due to the high operating pressure drops attributable to
the PTFE laminated fabric. Figures 15 through 19 show the increasing cost
of each fabric filter system by increasing pressure drops in one inch (W.G.)
increments. If the pressure drop is as much as 4" W.G. greater than found
in the pilot study, it would increase the annual operating costs by as much
as $8,000 per year for each filter medium.
It should be noted that these values do not include the operating costs
for the cleaning-air fan. A 4,000 ACFM fan operating at a 2" W.G. pressure
drop would cost approximately $205/year to run, based on the 6,240 hour work
year and current electrical costs. This value would double if the operating
pressure drop were 4" W.G. Even though this cost should be considered in
total operating costs, it is fairly insignificant with respect to the rest
of the baghouse operating costs.
44
-------
en
en
8
S
CTi
Figure 15
The Impact of Varying Pressure Drop on Operating Costs
Teflon Felt Operating Costs vs. Gas-to-Cloth Ratio
50 r-
45
40
a .
*i
o
35
30
25
20
15
KEY;
Pilot Plant Ap
Pilot Plant Ap + 1" w.G.
Pilot Plant Ap + 2" W.G.
Pilot Plant Ap + 3" W.G.
Pilot Plant Ap + 4" W.G.
V Pilot Plant Ap at Old Price
of $75/Bag
8
10
12
Gas-to-Cloth Ratio (lm/Ft. )
45
-------
Figure 16
The Itnpact of Varying Pressure Drop on Operating Costs
Laminate Operating Costs vs. Gas-to-Cloth Ratio
40r
35
ro
O
30
25
g 20
(Ti
15
10
O Pilot Plant Ap
D Pilot Plant Ap + 1" w.G.
A Pilot Plant Ap + 2" W.G.
O Pilot Plant Ap + 3" W.G.
O Pilot Plant Ap + 4" W.G.
I . I i I
6 8
Gas-to-Cloth Ratio
10
12
46
-------
Figure 17
The Impact of Varying Pressure Drop on Operating Costs
Felted Glass Operating Costs vs. Gas-to-Cloth Patio
30
25
3
fi 20
o
i-H
I
is
1 1
s
10
KEY;
O
Pilot Plant Ap
D Pilot Plant Ap + 1" W.G.
A Pilot Plant Ap + 2" W.G.
O Pilot Plant Ap + 3" W.G.
<0> Pilot Plant Ap + 4" W.G.
6 8
Gas-to-Cloth Ratio (ACFM/Ft.2)
10
12
47
-------
Figure 18
The linpact of Varying Pressure Drop on Operating Costs
Woven Glass (15 Oz.) Operating Cost vs. Gas-to-Cloth Ratio
30-
25
a
n
o
H
" 20
3
01
8 15
10
0
_L
KEY:
O Pilot Plant Ap
D Pilot Plant Ap + 1" W.G.
A Pilot Plant Ap + 2" W.G.
O Pilot Plant Ap + 3" W.G.
Pilot Plant Ap + 4" W.G.
6 8
Gas-to-Cloth Ratio
10
12
48
-------
Figure 19
The' Impact of Varying Pressure Drop on Derating Costs
Vtoven Glass (!zz.5 Oz.) Operating Costs vs. Gas-to-Cloth Ratio
30r
25
i i
a
n
o
w
-P
20
-5 15
10
r--
r-
cn
KEY;
O Pilot Plant Ap
D Pilot Plant Ap + 1" W.G.
A Pilot Plant Ap + 2" W.G.
O Pilot Plant Ap + 3" W.G.
O Pilot Plant Ap + 4" W.G.
6 8
Gas-to-Cloth Ratio (ACFM/Ft- )
10
12
49
-------
Annualized costs for baghouses with these filter media are graphed in
Figure 20. These values are based on the straight line method of deprecia-
tion over 15 years (6 2/3% per year). Capital costs are assumed to be equal
to the amount of depreciation; therefore, depreciation plus other capital
charges amount to 13 1/3 percent of the initial capital costs of the equip-
ment. Annualized costs would then equal the annual operating costs plus
13 1/3 percent of the installed cost.
The 15 oz. woven glass fabric is the least expensive with respect to
annualized costs ($0.56, $0.36, $0.37 and $0.43 per ACFM for gas-to-cloth
ratios of 2.9/1, 5.8/1, 8.9/1 and 11.3/1) with the 22.5 oz. woven glass and
the experimental felted glass close behind. The new Teflon felt bag price
makes it very competitive with the PTFE laminate at low gas-to-cloth ratios,
and makes it less expensive (again due to the higher operating pressure drop
of the PTFE laminate fabric) at gas-to-cloth ratios higher than 5.8/1.
Figure 21 shows the amount of the decrease in Teflon felt annualized costs
due to the lowered bag price.
50
-------
Figure 20
Qjiparison of Five Filter Media for Annualized Cost
vs.
Gas-tcr-Cloth Ratio
80
B
II
a
n
o
a
8
8
N
70
r-
i--
60
50
40
30
KEY;
Teflon Felt
Gore-Tex PTFE Laoninate
O Huyck Experimental Felted Glass
Globe Albany 22.5 Oz. Wbven Glass
Globe Albany 15 Oz. Woven Glass
o
D
20
6 8 10
Gas-to-Cloth Ratio (ACFM/Ft.2)
12
51
-------
90
80h
70
en
&
fO
o
60
50
1
H
40
30
20
Figure 21
The Effects of Bag Price Reduction on Annualized Costs
vs.
Gas-to-Cloth Ratio for Teflon Felt
KEY;
O $75/Bag, Pilot Plant Ap
$53/Bag, Pilot Plant Ap
6 8
Gas-to-Cloth Ratio (ACFPVFt.2)
10
12
52
-------
OPERATION
Baghouse No. 1 (the Teflon house) was initially brought on line on
Novenfoer 7, 1976 for debugging and brought on line again on Decerrber 15
through 17. The Gore-Tex house was brought on line on December 29, 1976.
Current start-up and operating procedures are listed following this section.
After four months of operation, two additional procedures were added: the
boilers would be brought up to load before the baghouses would be brought
on line and the baghouses would be shut down one hour before the boilers.
Flue gases would be vented through the boiler stack during these tiites.
The first problem encountered when Baghouse No. 1 was brought on line
was that the instrumentation system controller failed to maintain stable
conditions. This poor response caused the duct gas heater to naifunction
shorting out the system. One measure taken to solve this problem was the
redesign of the burner area. In the December start-up the system controller
began to over-respond to the stack cap closure, creating a pressure surge.
A representative of Taylor Instruments recommended a dartpering valve to
decrease the sensitivity of the primary signal to the system controller.
This was installed in February, 1977.
The cleaning-air fan in Baghouse No. 2 was found to be cracked, causing
an outage of that unit until it could be replaced. The severely cold
weather during February, 1977, created other problems. The damper operator
in Baghouse No. 2 was damaged and had to be totally replaced. Also, freezing
occurred in the control system air lines. The revamping of the compressed
air system included the installation of after-coolers on each compressor and
a larger capacity air dryer for the system.
Maintenance activities through the year were varied. Standard mainte-
nance procedures are located in Appendix A-4. A continuously running pneu-
matic purge was installed on Baghouse No. 1's stack to clear the pressure
tap of moisture and dust in June, 1977. An access hatch was also installed
on the stack so that cleaning and maintenance of the stack damper could be
more easily performed. In August, maintenance activities included recalibra-
tion of the inlet differential pressure transmitter by shifting the zero to
53
-------
make it read properly, replacement of a vortex damper positioner that had
been misadjusted, replacement of wires between the control house and compres-
sor No. 2 because of a short in the wiring, and replacement of a flame rod
in the heater since it would not come on during "pre-heat". Other mainte-
nance activities were tightening of the belts on the fan, which solved the
problem of system fan failure shutting down the system; adjusting the stack
pressure alarm setting from 1.0" to 1.5" on each side of zero so that the
danper control arm would not set off the alarm and shut down sequence when
the cap started closing; installing an air scoop on Unit Ho. 1 at the junc-
tion of the exhaust stack and the inlet to the cleaning air fan duct since
no dead head pressure was registering and the system did not appear to be
cleaning properly; and finally, replacing gasketing on D5B and adjusting the
rest of the dampers for a tighter fit.
Again in September the main fan control system began to malfunction,
shutting down the system, and the cleaning damper leaks were still causing
loss of cleaning pressure and, therefore, cleaning effectiveness. November
brought a heater malfunction and an induced draft fan failure for Boiler
No. 1. Both were repaired. In December, the purge damper was sealed to
improve cleaning air pressure and cleaning-air fan belts and sheaves were
replaced. Also, the line between the cleaning-air plenum and the control
room gauge was obstructed and had to be replaced.
Maintenance problems of Baghouse Ho. 2 during 1977 have included the
repair of its gas burner because of a surface overheat in May and the repair
of the differential pressure transmitter for the controller in August. While
the transmitter was out of commission the system was operated manually with
the wire from relay No. 45 removed so that the alarm would not shut it down.
The heater wires had to be replaced again in August and one cell was not
operating because the clevis had separated from the damper cylinder and the
cylinder was jammed in the "up" position this was repaired.
Back pressure into the boiler became a problem in Unit No. 2, so the
boiler stack damper was held open during operation. The stack cap was open
all of September with no problems, so this became standard for operation
54
-------
of Baghouse Mo. 2. Other problems encountered were low cleaning air pres-
sure (improved by welding the purge damper closed), obstruction of the line
between the cleaning-air plenum and the control roan gauge, and a burner
short circuit (rewired with asbestos wire).
Another problem encountered was the deterioration of the silicone
gasketing material around the hatch covers and dampers in January, 1977.
The problem was attributed to the high temperature and the SO- concentra-
tions in the flue gas. The replacement was asbestos tad-pole style
gasketing, but in November, 1977, a damper sealing problem became
apparent - caused by the hardening of the asbestos into a compressed
state. At this time an asbestos tad-pole design gasket with a Teflon
coating and with a spring-wire mesh center is being tested in the purge
vent damper (D5A) in Bagliouse No. 1. This appears to solve the problems
of compression and hardening.
By April, 1977, it was evident that too heavy a filter "cake" was on
the bags and that they would have to be cleaned. An industrial cleaning
contractor was hired in May to raise each bag above the tube sheet and to
manually vacuum each bag. During the month following bag cleaning the
average pressure drop across the Teflon house was 7" W.G. The Teflon felt
bags were vacuumed in July and again in November the latter time because
the pressure drop became too high for effective cleaning and visual inspec-
tion of the bags showed heavy pearling (an indication of sub-dew point
excursions).
Although Baghouse No. 2, outfitted with Gore-Tex bags of PTFE laminate,
had only started up December 29, 1976, by April eight bags had been replaced;
four due to material failure and four due to shrinkage which forced the
cages above the tube sheets. Twenty-five more were seriously damaged during
vacuum cleaning in May. An inspection in July found thirty more bags to
have holes or tears in them, apparently due to some maintenance activity.
Since there were no more spare Gore-Tex bags, one complete cell of touse
No. 2 was filled with Globe Albany woven glass bags (these were 22.5 oz./
yd.2 bags taken from the pilot facility at Nashville Thermal Transfer
55
-------
Corporation) on July 27. A representative of Gore Associates suggested that
the Gore-Tex bags could be repaired and suggested that the bags be steam
cleaned instead of vacuumed to lower the risk of damage. In October, three
more bags were lost; one was shredded and two had one-inch diameter holes.
In November, fourteen bags were discovered to have one and a half inch holes
in the upper two feet of the bag, primarily where the bags made contact with
cage ribs.
56
-------
List of Bag Replacements
Baghouse No. 2
Gore-Tex Bag Loss
Date
4/77
5/77
7/77
10/77
11/77
No. of Bags
Replaced
8
25
30
3
14
Garments
4 Shrank (Forced Cage Up)
4 Material Failure
First Cleaning Was During May
Serious Damage During Cleaning
Holes or tears apparently due to
maintenance. Gore said bags should
be steam cleaned in place; can
repair these.
1 Shredded, 2 w/Snall Holes
Holes l-lV long in upper 2 feet
of bag where contact rib of cage.
Thirty-six (36) Huyck experimental glass bags put in House No. 2, Cell
6A, 3/28/77.
Thirty-six (36) Globe Albany 22% oz./yd.2 Wven bags put in House No. 2
Cell 3, 5/27/77.
Thirty-six (36) Globe Albany 15 oz./yd. bags installed in House No. 2,
Cell 5, 2/21/78.
Three (3) Ncmex felt bags installed in House No. 2, Cells No. 1, 4 and 9,
2/21/78.
57
-------
START-UP AID OPIRATEIG PPDCEDUPES
I Start-Up Preliminary Procedures
A. These devices must be closed:
1. ftain Disconnect Switch
2. All Motor Starter Doors
3. All Motor Starter Circuit Breakers
4. All ftotor Disconnects
5. Control Circuit Breakers
B. Fuses must be in place and of recommended rating.
C. Air dryer switch must be on before air compressor is
started.
D. Press air compressor "start" button and "air compressor on"
indicating light must be lighted.
E. All trouble annunciator lights must be out after pressing
silence button.
F. Turn mode selector from "off" to "test" to check operation
of all drives and dampers (except stack cap).
G. Turn mode selector to "off".
II Automatic Operating Procedures
A. Turn mode selector to '"automatic".
B. Wait about 10 seconds until all relays have reset.
C. Press "auto start" pushbutton.
D. System will start-up and operate as described.
Ill Manual Operating Procedures:
A. Turn selector switch to "manual".
58
-------
START-UP AND OPERATING PPOCEDURES (OONTItlUED)
B. Wait about 10 seconds until all relays have reset.
C. Start preheat cycle.
D. Wait until baghouse is up to 250° F (on digital read out)
and exhaust stack is up to 180° F (on temperature recorder)
E. Press normal start pushbutton.
59
-------
DATA OBTAINED
Inlets to both baghouses were characterized by both EPA Methods 1-5
testing (substituting a medium porosity alundum thimble for a heated glass
filter) and by continuous recording monitors. The ranges of various para-
meters as well as average values can be found in Table 5. These averages
are based on six tests for the inlet to Baghouse No. 1 and three for the
inlet to Baghouse No..2. The data vary only slightly between houses.
In January, 1973, (prior to the pilot study) the North Carolina Air
Quality Division performed testing on two consecutive days to determine the
quantity of particulate emissions from the stack for Kerr's Boiler No. 2.
The Orsat analysis of the stack gas showed the oxygen content to be 10% and
the carbon dioxide content to be 9.5% with no carbon monoxide. An emission
factor of 0.36 Ib./million BTU was assigned to each Kerr boiler, based upon
design BTU input. This factor multiplied by the actual BTU input (a compu-
tation based on the actual steam production rate and the generating effi-
ciency of 77%) yielded the allowable emission rates of 25.1 Ib./hr. and 27.8
Ib./hr. for the two tests which had actual emission rates of 131.4 Ib./hr.
and 135.6 Ib./hr., respectively.
Outlet emissions testing during the first year of the assessment
project's operation proved that the baghouse emissions would be in compliance
with air pollution regulations under most conditions. The high oxygen
content in the gas results in higher excess air and higher emission rates.
Better results could be obtained by elimnating some of this oxygen. Table
6 lists a summary of outlet data acquired by EPA Methods 1 through 5 sampling
as well as the data recorded on baghouse monitors. Table 7 lists the para-
meters used in computing the emission rates for specific tests.
Since the gas-to-cloth ratio did not vary much in 1977 (4.5/1 to 5.8/1)
it is assumed that this had very little effect on outlet grain load. How-
ever, coal variablity, bag on-stream time, across-house pressure drop and
boiler load are interrelated in affecting each other and, possibly, outlet
loading. From Table 7 it does not appear that boiler load has any effect
upon the outlet loading. Nor does it appear to influence any other parameter.
60
-------
Table 5
Inlet Characterization
1977
Baghouse #1
Teflon Felt
002 (*)
CO (%)
02 (%)
MDisture (%)
T (° F)
Gas Volume (ACFM)
Grain Loading (Grains/DSCF)
Source Testing
(EPA Method 5)
Baghouse #2
Largely Gore-Tex
4.5
(Range 3.9-5)
15.2
(Range 14.5-16.8)
5.1
(Range 3.0-8.3)
322
(Range 310-350)
37,700
(Range 34,900-40,700)
0.5356
(Range 0.3846-0.7878)
4.4
(Range 3.9-4.7)
14.6
(Range 13.7-15.5)
3.1
(Range 2.7-3.3)
317
(Range 310-330)
35,300
(Range 33,100-38,100)
0.4272
(Range 0.3999-0.4593)
Continuous Mpnitoring
Boiler Stack Temperature
Inlet Temperature
Inlet Flow Rate
Inlet Opacity
300° F
(Range 270-330° F)
270° F
(Range 100 -320° F)
95° F
(Range 50-120° F)*
310° F
(Range 240-335° F)
76.7 Ft./Sec. 61.1 Ft./Sec.
(Range 59.44-88 Ft./Sec.)** (Range 24-74 Ft./Sec.)**
40%
(Range 18-80%)
*The stack cap is always open on #2.
**Coirputed with the average inlet temperature, the values were then adjusted
by dividing the flow rate derived by 1.25 and 1.5 for baghouses 1 and 2,
respectively, to correspond to values obtained via pitot tube.
61
-------
Table 6
Outlet Characterization
1977
002 (%)
CO (%)
02 (%)
Moisture (%)
T (° F)
Gas Volume (ACFM)
Grain Loading (Grains/DSCF)
Emission. Factor (Ii>./106 BTU)
Baghouse #1
Teflon Felt
Baghouse #2
Largely Gore-Tex
4.0
(Range 3.7-4.3)
Source Testing
(EPA Method 5)
4.2
(Range 3.8-4.9)
14.9
(Range 14.2-15.3)
4.0
(Range 2.8-4.8)
291
(Range 272-320)
46,700
0
14.6
(Range 13.8-15.8)
3.5
(Range 2.7-5.0)
292
(Range 260-307)
45,600
(Range 44,500-49,000) (Range 44,200-46,800)
0.0367
0.0605
(Range 0.0175-0.0912) (Range 0.0263-0.1230)
0.16778
0.36963
(Range 0.06299-0.41764) (Range 0.11846-0.72096)
Continuous Monitoring
Outlet Tenperature (° F)
Outlet Flow Rate (ft./s)
Ap Ifouse ("H20)
Ap Main Fan ("H20)
Reverse-Air Fan Temperature
(° F)
Outlet Opacity (%)
280
(Range 230-305)
64
(Range 43.2-74.8)*
7.1
(Range 2.7-13.8)
10.8
(Range 3.6- >15)
275
(Range 230-300)
290
(Range 210-310)
69.3
(Range 39.7-77.4)*
12.2
(Range 8.7->15)
13.2
(Range 9.6-> 15)
300
(Range 230-315)
(Range 4-20)
*Based on Average Outlet Tenperature
62
-------
Table 7
Sunmary of EPA Method 5 Outlet Data
Baghouse
Run #
1
2
9
30
31
32
Baghouse
7
11
12
No. 1
Date
12/16/76
12/17/76
4/26/77
9/1/77
9/1/77
9/1/77
No. 2
1/20/77
4/27/77
4/28/78
Approximate
Gas-to-Cloth
Ratio
5.5
5.4
5.1
5.8
5.7
5.8
5.8
5.4
5.8
oscm
30,640
29,088
31,635
31,106
30,714
31,186
32,747
30,431
26,949
1977
% 02
6.7
7.1
6.4
5.6
5.7
5.6
5.1
6.5
6.5
Outlet Loading
Lb./Hr.
8.85
8.21
24.72
4.67
3.48
7.45
34.51
6.85
13.80
Average
Emission Factor Boiler Load
Iib./106_BTU_ Lb./Hr.
0.14746
0.13598
0.41764
0.09170
0.06799
0.14592
0.72096
0.11846
0.26948
41,250
45,250
38,000
32,000
37,600
32,600
44,000
40,500
50,600
-------
Coal variability does appear to be the major influence in baghouse
operation and outlet loading. During 1977 a poorer quality of coal was
used in April, August and December due to heavy rains and flooding, and
the coal miner's strike. The coal used during these months had a higher
volume of water decreasing the ability to get the boilers up to load and
was generally of poorer quality. When used, this coal caused an increase
in across-house pressure drop to 12" W.G. and above. In April the pressure
drop increases kept causing the baghouses to shut down. The primary causes
of the pressure drop increases were the increase in water content and the
increase in inlet loading - both causing the bags to "plug" up.
A coal analysis was performed on the standard coal used early in
December 1977 and can be found in Table 8. Ash taken from Baghouse No. 2
at this time was found to have an unburned carbon content of 25.21%. Still
using the poorer quality coal in February 1978 showed the unbumed carbon
content in the ash to be 33.81% and 34.39% for Baghouses 1 and 2 respectively.
Since on-stream time affects the filter media, it also affects baghouse
operation. The Qore-Tex filters underwent a great deal of abrasion in con-
tact with the metal ribs of the cages. There were instances of holes at
other locations which could be due to the flexing or acid attack. The
permeability of the new Gore-Tex bags ranged from 8.13 to 12.9 ft. /ft. /min.
with the average being 10.22 ft.3/ft.2/min. After one month on-stream
these bags had permeabilities of about 2.5 ft.3/ft,2/min. and the perms were
not improved by vacuuming the bags. Throughout the year bags were removed
periodically for perms. The highest found was 4.05 ft.3/ft.2/min. after
vacuuming. The bag had been on-stream less than three months. By November
1977 the average permeability (after vacuuming) was only 1.25 ft.3/ft.2/min.
It should be noted that manual industrial vacuuming can and did damage bags
in place, at Kerr. The vacuuming did not improve the pressure drop across
Baghouse No. 2.
The Teflon felt bags have responded somewhat better. New bags had a
perm range of 27.5 to 41.73 ft.3/ft.2/min. with an average of 33.12 ft.3/
ft.2/min. After two months on stream the bags had an average perm of 10.45
ft.3/ft.2/min. but were vacuumed to an average of 15.53 ft. /ft. /min. By
64
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Table 8
Coal Analysis
December 1977
I-5oisture
Ash
Volatile
Fixed Carbon
As Received
6.87 %
14.35 %
30.12 %
48.66 %
Dry
15.41 %
32.34 %
52.25 %
Sulfur
Carbon
Hydrogen
Oxygen & Nitrogen
0.67 %
65.49 %
4.21 %
8.41 %
0.72 %
70.32 %
4.52 %
9.03 %
Heat Value
BTU/lb.
As Received
11560
Dry
12412
MAF
14674
65
-------
i 2
April of 1977, some bags oould still be cleaned to 20.8 ft. /ft. /min. Indus-
trial vacuuming did not harm the fabric and lowered the across-house pressure
drop 5-8" W.G. each time it was done.
The across-house pressure drops have been found to be approximately four
inches higher in the Teflon house during the full scale demonstration than in
the pilot program. This could be attributable to the removal of the multi-
cyclones or to the longer on-stream time of the bags.
Also directly attributable to the removal of the multicylones at the
beginning of the demonstration project is the outlet particle sizing. Tables
9 through 11 show inertia! impactor characterizations of inlet and outlet,
mass emissions removal efficiencies, and particle size removal efficiencies.
(Tables A-2 through A-6 in Appendix A-5 show results of individual Andersen
tests on outlets.) Figure 22 shows the relationship of the average curve
for the pilot plant using Teflon felt (no nozzle wash was collected) and the
average curves for the demo unit with and without the nozzle washes. With-
out the nozzle wash, the curves approximate each other in shape, but the
demo is shifted up and to the left due to larger particles entering the
baghouse than during the pilot study when the multicyclone was in use.
66
-------
Table 9
Inlet Characterization
(Particle Sizing)
Mean of Andersen tests from Pilot Study.
1
2
3
4
5
6
7
8
Back-Up
Filter
Particle
Diameter,
>8.72
5.45
4.02
2.47
1.55
0.86
0.51
0.35
<0.35
Total
Loading
Grains/dscf
.145462
.03850
.02643
.01287
.01276
.00492
.00270
.00297
.00429
.25090
Brink test on inlet of Teflon felt house, 11/15/78.
1
2
3
4
5
6
Particle
Diameter,
>1.59
0.92
0.61
0.30
0.17
0.09
Total
Loading
Grains/dscf
.058312
.12987
.03973
.01882
.00767
.00465
.25904
.264153
.12987
.03973
.01882
.00767
.00465
.46488
, J.D., Mycock, J.C. and Lipsconib, W.O. Applying Fabric Filtration
to Coal Fired Industrial Boilers: A Pilot Scale Investigation. EPA-650/
2-74-058a, U.S. Environmental Protection Agency, Washington, D.C. August,
1975. 191 pp.
Probe + nozzle washes omitted from Stage 1
Probe + nozzle washes included in Stage 1
67
-------
Table 10
Outlet Characterization by Andersen Impactor
(Particle Sizing)
Mean values of 13 tests during 1977 on Teflon felt house, gas-to-cloth ratio 4.5-6/1.
Particle
Diameter,
>9.41
Cumulative %
Less Than Size Indicated
Loading
Grains/dscf
6.
4.
2.
1.
.60
.06
.85
.85
0.85
0.51
0.36
<0.36
77. 921
64.50
48.27
34.85
22.29
13.42
8.44
5.63
5.482
4.63
3.46
2.41
1.65
1.01
.63
.36
CO
Total
.00102J
.00062
.00075
.00062
.00058
.00041
.00023
.00013
.00026
.00462
.04229'
.00038
.00052
.00047
.00034
.00029
.00017
.00012
.00016
.04474
Mean values of 3 tests during 1977 on (largely) Gore-Tex house, gas-to-cloth ratio 4.5-6/1.
Particle
Diameter,
>10.43
7.32
4.51
3.17
2.06
0.95
0.57
0.41
< 0.41
Cumulative %
Less Than Size Indicated
66.411
55.14
42.32
35.36
27.07
17.68
10.06
6.19
Total
Loading
Grains/dscf
.003041
.00102
.00116
.00063
.00075
.00085
.00069
.00035
.00056
.00905
T>robe + nozzle washes emitted from Stage 1
Probe + nozzle washes included in Stage 1
-------
Table 11
Mass Emissions and Particle Size Removal Efficiencies
Mass Emissions Removal Efficiencies
Teflon Felt House
Best Case 95.45% @ .0175 gr/dscf outlet loading
Mean 93.15 @ .0367
Worst Case 88.42 @ .0912
(Largely) Gore-Tex House
93.42% @ .0263 gr/dscf
85.84 @ .0605
73.22 @ .1230
Particle Size Removal Efficiencies at G/C ratio of approx. 6/1 for both media.
Particle
Diameter, /i
.2
.3
.5
.7
1.0
1.5
2.0
3.0
5.0
7.0 -
10
20
Teflon Felt
Penetration
.0042
.0031
.0024
.0021
.0021
.0021
.0023
.0028
.0040
.0055
.0083
.0219
: House
Efficiency
99.58%
99.69
99.76
99.79
99.79
99.79
99.77
99.72
99.60
99.45
99.17
97.81
-Tex House
Overall
98.02
Penetration
.0075
.0063
.0054
.0051
.0050
.0051
.0054
.0061
.0077
.0094
.0122
.0223
Efficiency
99.25%
99.37
99.46
99.49
99.50
99.49
99.46
99.39
99.23
99.06
98.78
97.77
98.99
Particle size removal efficiencies are shown in the graph to the right.
Based on 1977 source (EPA Method 5) tests.
2
Based on 1977 Andersen tests on outlets of both houses, and 1978 Brink test on inlet
to Gore-Tex house (linear least squares data fit).
*
No probe and nozzle washes were collected.
10
O Teflon Felt
A Gore-Tex
Efficiency, %
99.9 59^ 98
S
o
M
O
H
to
H
o
CO
p-l
.7
.5
.1 "12
Penetration
-------
10
8
I
8
o
..0
.8
.6
.4
Full Scale With
Nozzle Wash
Full Scale Without
Nozzle Wash
O Pilot Plant
.2 .5 1 2 5 10 20 40 60
Mean Cumulative % Less Than Size Indicated
80
90
Figure 22
Conparison of Pilot Plant with Full Scale Assessment Project in
Terms of Outlet Particle Size Distribution
(Teflon Felt - Gas-to-Cloth Ratio 4.5-6/1)
70
-------
FUTURE PLANS
The EPA has elected to exercise all contract options, thus the two
demonstration units will continue to be operated and tested throughout 1978
and 1979. House No. 1 will continue to be operated with Teflon felt as the
filter media. The program plan calls for replacement of the Gore-Tex with
a series of other filter media, thus obtaining cost, life and performance
data on a variety of candidate media considered potentially suitable for
fly ash control applications. The initial candidate materials include both
a woven glass and an experimental felted glass.
Estimates for a new multi-cyclone and for refurbishing the interior of
one of the existing multi-cyclones are being collected. If economically
feasible, a multi-cyclone will be used as a particulate pre-collector for
House No. 1 (the Teflon house) for comparison with results obtained by
baghouse use alone.
Operation of the fabric filter as an SC>2 removal system by the use of
two (2) injected sorbents will begin in 1979.
71
-------
APPENDIX
Section Contents
A-l Units of Measure - Conversions 74
Glossary of Terms 75
A-2 SD-10 General Arrangement 80
Shock-Drag Bag Cleaning System 81
A-3 List of Equipment Included in Installed Costs 83
Bill of Materials for Actual Kerr Installation 84
List of Components Included in the Flange-to-
Flange 1978 Collector Costs
Installed, Operating and Annualized Costs for
Electrostatic Precipitators - 1978
Sample Calculations of Operating and Annualized
Costs for Fabric Filtration
Sample Calculations of Operating and Annualized
Costs for Electrostatic Precipitation
A-4 Baghouse Maintenance Procedures
Baghouse Maintenance Schedule
Spare Parts List
A-5 Results of Andersen Impactor Tests on Outlets
72
-------
APPENDIX A-l
Units of Measure - Conversions
Glossary of Terms
73
-------
UNITS OF MEASURE - CONVERSIONS
Environemntal Protection Agency policy is to express all measure-
ments in Agency documents in metric units. When implementing this
practice will result in undue costs or lads: of clarity, conversion
factors are provided for the non-netric units used in a report. Gen-
erally, this report uses British units of measure. For conversion to
the metric system, use the following conversions:
TO CONVERT FRCtl
op
ft.
ft.2
ft. 3
ft/min (fpm)
ft.3/min
in
in2
oz
oz/yd2
grains
grains/ft3
Ib force
Ib mass
lb/ft2
in H20/f t/min
in H0/f t/min
lb/ft2
TO
°C
meters
meters2
meters-^
centijneters/sec
centinetersVsec
centimeters
centimeters^
grams
grams/meter2
grams
grams/meter^
dynes
kilograms
grams/centimeter'1
on Il20/cm/sec
cm H20/on/sec
o
gm/cro
MULTIPLY BY
5_ (°F~32)
9
0.304
0.0929
0.0283
0.508
471.9
2.54
6.45
28.34
33.89
0.0647
2.288
4.44 x 105
0.453
0.488
5.00
10.24
74
-------
GLOSSARY OF TERMS
ACID DEW-POINT - The temperature at wliich the condensation of the acid
vapors initiates for a given state of humidity and pressure.
AIR-TO-CLOTH RATIO - The volumetric rate of capacity of a fabric filter;
the volume of air (gas), cubic feet per minute, per square foot of
filter media (fabric).*
BAG- The customary form of filter element. Also known as tube, stocking,
etc. Can be unsupported (dust on inside) or used on the outside of
a grid support (dust on the outside).
BLINDING (BLINDED)- The loading, or accumulation, of filter cake to the
point where capacity rate is diminished. Also termed "plugged".
CLOTH - In general, a pliant fabric; - woven, knitted, felted, or other-
vase formed of any textile fiber, wire, or other suitable material.
CLOTH WEIGHT - Is usually expressed in ounces per square yard or ounces
per square foot. However, cotton sateen is often specified at a
certain number of linear yards per pound of designated width. For
example, a 54" - 1.05 sateen measures 1.05 linear yards per pound
in a 54" width.
DAMPER - An adjustable plate installed in a duct for the purpose of reg-
ulating air flow.
DIMENSIONAL STABILITY - Ability of the fabric to retain finished length
and width, under stress, in hot or moist atmosphere.
DUST LOADING - The weight of solid particulate suspended in an air (gas)
stream, usually expressed in terms of grains per cubic foot, grams
per cubic meter or pounds per thousand pounds of gas.
*Although it is EPA's policy to use the metric system for quantative
descriptions, the British system is used in this report because not to
do so would tend to confuse some readers fron industry. Readers who
are more accustomed to metric units may use the table of conversions in
the appendix to facilitate the translation.
75
-------
GLOSSARY OF TERMS
FABRIC - A planar structure produced by interlacing yarns, fibers or
filaments.
KUiTThU fabrics are produced by interlooping strands of yarn, etc.
TOVEN fabrics are produced by interlacing strands at more or less
right angles.
BffiJDED fabrics are structures built up by the interlocking action
of the fibers themselves, without spinning, weaving or knitting.
FELTED fabrics are structures built up by the interloclcing action
of the fibers themselves, without spinning, weaving or knitting.
FILTER MEDIA - The substrate support for the filter cake; the fabric
upon which the filter cake is built.
FILTER VELOCITY - The velocity, feet per minute, at which the air (gas)
passes through the filter media, or rather the velocity of approach
to the media. The filter capacity rate.
FILTRATION RATE - The volume of air (gas), cubic feet per minute, passing
through one square foot of filter media.
FRACTIONAL EFFICIENCY - The determination of collection efficiency for
any specific size or size ranae of particles.
GRAIN - 1/7000 pound or approximately 65 milligrams.
INCH OF WATER - A unit of pressure equal to the pressure exerted by a
column of liquid water one inch high at a standard temperature.
The standard temperature is ordinarily taken as 70° F. One inch
of water at 70° F. = 5.196 Ib per sq. ft.
MASS MEAN PARTICLE DIAMETER - Refers to the point of a curve plotting
particle diameter versus cumulative mass percent that shows 50%
of the material is less than and 50% of the material is greater
than the indicated particle diameter.
MICRON (um) - A unit of length, the thousandth part of 1 im or the
millionth of a meter, (approximately 1/25,000 of an inch).
MULLEN BURST - The pressure necessary to rupture a secured fabric speci-
men, usually expressed in pounds per square inch.
76
-------
GLOSSARY OF TERtIS
NEEDLED FELT - A felt made by the placment of loose fiber in a systematic
alignment, with barbed needles moving up and down, pushing and pulling
the fibers to form an interlocking of adjacent fibers.
NON-VtoVEN FELT - A felt made either by needling, matting of fibers or
compressing with a bonding agent for permanency.
NYLON - A manufactured fiber in which the fiber forming substance is any
long-chain synthetic polyamide having recurring amide groups.
PEARLING - Refers to a condition of the dust cake on the fabric wliich
appears as nodular structures of agglomerated dust.
PERMEABILITY, FABRIC - Measured on Frazier porosity meter, or Gurley
permeometer, etc. Not to be confused with dust permeability. The
ability of air (gas) to pass through the fabric, expressed in cubic
feet of air per minute per square foot of fabric with a 0.5" F^O
pressure differential.
PITOT TUBE - A means of measuring velocity pressure. A device consisting
of two tubes - one serving to measure the total or impact pressure
existing in an air stream, the other to measure the static pressure
only. When both tubes are connected across a differential pressure
measuring device, the static pressure is compensated automatically
and the velocity pressure only is registered.
POROSITY, FABRIC - Term often used interchangeably with permeability.
Actually percentage of voids per unit volume - therefore, the term
is improperly used where permeability is intended.
PRESSURE, STATIC - The potential pressure exerted in all direction by
a fluid at rest. For a fluid in motion, it is measured in a direc-
tion normal to the direction of flow. Usually expressed in inches
water gage, when dealing with air.
PRESSURE, TOTAL - The algebraic sum of the velocity pressure and the
static pressure (with due regard to sign). In gas-handling systems
these pressures are usually expressed in inches water gage. The
sum of the static pressure and the velocity pressure.
77
-------
GLOSSARY OF TERMS
TEMPERATURE, DEW-POINT - The temperature at which the condensation of
water vapor in a space begins for a given state of humidity and
pressure as the temperature of the vapor is reduced. The tempera-
ture corresponding to saturation (100 per cent relative humidity)
for a given absolute humidity at constant pressure.
TWILL WEAVE - Warp yarns floating over or under at least two consecutive
picks from lower left to upper right, with the point of intersection
moving one yarn outward and upward or downward on succeeding picks,
causing diagonal lines in the cloth.
VELOCITY HMD - Same as velocity pressure. (See Pressure, Velocity).
VELOCITY OF APPROACH - The velocity of air (gas), feet per minute, normal
to the face of the filter media.
VELOCITY TRAVERSE - A method of determining the average air velocity in
a duct. A duct, round or rectangular, is divided into numerous
sections of equal area. The velocity is determined in each area
and the mean is taken of the sun.
78
-------
APPENDIX A-2
SD-10 General Arrangement
Shock-Drag Bag Cleaning System
79
-------
General Arrangement 5D-IO
00
o
Pyramid Hopper
TO FLAMGl
Figure A-l
SD-10 General Arrangement with Pyrainid toppers
The arrangement of the SD-10 is very similar to that of the RAC-3's in use at Kerr.
-------
Figure A-2
Baghouse Pictorial Showing Gas Flow
Figure A-3
Baghouse Pictorial Showing Gas Flow
STEP 2
Dirty gases enter
the classifier at one
end through a wide
center Inlet, are deflected
downward Into the hopper,
then forced to reverse direc-
tion before entering the fabric
filter cells. This quick change In the
direction of flow removes the heavy
participate before the gases reach the
niter bags.
THE FABRIC FILTER
The gases now pass through the
fabric, depositing the remaining
participate on the outer surface of
the bags. This deposit Is periodi-
cally removed from the fabric
surface by the unique SHOCK-
DRAG Cleaning System, design-
ed to prolong bag life by mini-
mizing distortion of the fibers.
00
STEP 3
STEP 4
SHOCK
As solid matter collects on the
outside of the (liter bag, a cake or
crust Is formed which begins to
restrict the flow of gas. When the
pressure drop across the fabric
reaches a predetermined level, a
damper Is actuated which Isolates
the cell from the main gas stream
and simultaneously Introduces
cleaning gas flowing In the re-
verse direction. The Inrush of
cleaning gas rapidly distends the
filter bags, cracking the dust cake
and permitting the large agglo-
merated pieces to fall Into the
hopper.
DRAG
Now that the SHOCK has broken
off the outer crust, the flow of
clean gas continues, pushing and
pulling the dust particles away
from the fabric In an operation
called DRAG. These finer parti-
cles are forced from the bag and
propelled Into the hopper. The
Envlro-Clean SD Is unique In that
It provides both SHOCK end
DRAG In Independently control-
lable amounts. The Drag cleaning
phase has proven significant In
minimizing re-entralnment of the
fine partlculate during the clean-
Ing cycle.
Figure A-4
Baghouse Pictorial Showing Gas Flow - Shock
Figure A-5
Baghouse Pictorial Showing Gas Flow - Drag
-------
APPENDIX A-3
List of Equipment Included in Installed Costs
Bill of Materials for Actual Kerr Installation
List of Components Included in the Flange-to-Flange
1978 Collector Costs
Installed, Operating and Annualized Costs for Electro-
static Precipitators - 1978
Sample Calculations of Operating and Annualized Costs
for Fabric Filtration
Sample Calculations of Operating and Annualized Costs
for Electrostatic Precipitation
82
-------
List of Equipment Included in "Installed Cost"
COLLECTOR
Standard Collector Conponents
Bags
COLLECTOR AUXILIARY COMPONENTS
Support Structure
Cleaning Control Panel (Standard)
Reverse-Air Blower
Reverse-Air Service Platform and Railing
High-Pressure Switch
High-Temperature Switch
Rotary Air Lock
Handrails
Ladder
Paint
Insulation
SYSTEM ALJXTT.TARIES
Control Panel
Cross Screw
Ductwork
System Fan
Relief Cap
Installation
ENGINEERING SERVICES
Site Survey
Design & Engineering
Drawings
Start-Up and Instruct
83
-------
BILL OF MATERIALS
Job No.
[tern
1
2
3
4
5
6
7
8
9
10
11
12
13
76-100
Qty.
2
2
1296
1
2
1 Lot
1
1
1 Lot
1
2
6
1
Part No.
S-9101P9
S-9097
S-2096
S-9102P9
76-100-
76-100-
76-100-
76-100-
76-100-
76-100-
S-9144
76-100-
Material
648-RAC3-5-104 Baghouse with
Insulation
ES16, Arrg. 9, Reverse-Air Fan
Assembly
Rigid Cage Assemblies
(Included in 1)
Conpressor System
9 Module Pyramid Hoppers With
Insulation (Included in 1)
Structure and Walkways
Pent House Assembly
System Motor Control Center
Ductwork With Relief Caps and
Dampers
Control House
System Fan Assemblies
Double Dump Valves
Motor Speed Control Center
14
15
(Included in 8)
76-100- System Control Console
(Included in 8)
Heat Control System
(Included in 8)
Actual
Costs
$ 120,700
3,800
8,000
19,810
7,977
45,406
64,498
39,648
27,585
9,000
84
-------
List of Conponents Included in the Flange-to-Flange
1978 Collector Costs
(Coal-Fired Boiler Applications)
Collector
Supports
Tinier
Reverse-Air Fan
Feverse-Air Fan Platform
High Pressure
High Temperature
Double Dump Valves
Heater
Ladder
Paint
Insulation (2 Inches Thick)
85
-------
Electrostatic Precipitabor - 1978
Installed, Operating and Annualized Costs
Efficiency
90%
Installed
SCA Costs
247 $250,750
($3.58/ACFM)
Operating
Costs
$26,832
($0.38/ACFM)
Annualized
Costs
$60,182
($0.86/ACFM)
95%
309 274,550
(S3.92/ACFM)
27,252
($0.39/ACFM)
63,767
($0.91/ACFM)
99%
463 366,520
($5.24/ACFM)
36,869
($0.53/ACFM)
85,616
($1.22/ACFM)
86
-------
Fabric Filter
Operating and Annual!zed Costs
Sairple Calculations
Formulae for calculating theoretical operating and annualized cost of control
were taken from: Edminsten, N.G. and Bunyard, F.L. , "A Systematic Procedure
for Determining the Cost of Controlling Particulate Emissions from Industrial
Sources", JAPCA, V20 N7, p. 446, July, 1970.
I. Fabric Filter Operating Cost:
Case - Teflon Felt at A/C = 5.8/1
Where: G = Theoretical Annual Cost for Operation and
Maintenance
S = Design Capacity, ACFM
P = Pressure Drop, Inches of Water
E = Fan Efficiency, Assumed to be 60% (Expressed
as 0.60)
0.7457 - A Constant, 1 Horsepower = .7457 Kilowatt
H = Annual Operating Time, 6240 Hours
(24 Hours/Day X 5 Days/Week X 52 Weeks /Year
6240 HoursAear)
K = Power Costs, S/KWH
M = Maintenance Cost, $/ACFM (Based on 25% Bag
Replacement Per Year)
In this case:
S = 70,000 ACFM
P = 3.4 Inches of Water
E = 60%
H = 6,240 Hours
K = $0.021/KWH
M = (No. of Bags in House X 25% Replacement Rate X
Cost Per Bag) T S
87
-------
Sample Calculations
(Continued)
M = 1080 Bags X .25 X $53/Eag = $,20443/ACFM
70,000 ACFM
Assuming a 60% fan efficiency reduces the above
equation for G to:
G = S (195.5 X 10~6 PHK + M)
Substituting the figures above yields:
G = 70,000 [(195.5 X 10~6 X 3.4 X 6240 X 0.021) + 0.20443]
= 70,000 (.08710 + .20443)
= 70,000 (.29153)
= 20,410 (Dollars)
II. Total annualized cost of control is equal to the annual operating
cost plus the annualized capital cost.
Annualized Capital Cost = 0.133 X Installed Costs
Assumptions:
1. Purchase and installation costs are depreciated over
fifteen (15) years.
2. The straight line method of depreciation (6 2/3% per
year) is used.
3. Other costs called capital charges are assumed to be
equal to the amount of depreciation. Therefore,
depreciation plus other capital charges amount to
13 1/3 percent of the initial capital costs of the
equipment.
In this case: Teflon Felt at A/C = 5.8/1
Total Annualized Cost of Control = .133 X Installed Costs +
Operating Costs
(.133 X 153,700) + 20,410
= 40,852 (Dollars)
88
-------
Electrostatic Precipitator
Operating and Annual!zed Costs
Sample Calculations
Formulae for calculating theoretical operating and annualized cost of control
were taken from: Edminsten, N.G. and Bunyard, F.L., "A Systematic Procedure
for Determining the Cost of Controlling Particulate Emissions from Industrial
Sources", JAPCA V 20 N 7, p. 446, July, 1970.
I. Flange-to-flange cost for a 99% efficient ESP, sized for 70,000
ACFM was estimated as $215,600 by an ESP manufacturer. Typically,
installation costs would be 70% of the flange-to-flange costs so
a total ":.nstalled" cost would be approximately $366,520.
II. Operating Costs: Case 99% Efficiency
G = S (JHK + M)
Where: G = Theoretical Annual Cost for Operation and
> Maintenance
S Design Capacity in ACFM
J = Power Consumption (Total Connected load X Power
Factor) in KW/ACFM
H = Annual Operating Time, Hours/Year = 6,240
K = Power Cost ($0.021/KWH in this Case)
M .Maintenance Cost - Moderate Amount of 3% of the
Flange-to-Flange Cost ($/ACFM)
X S,240 X 0.021 + M
= 70,000 (0.4343 + .0924)
= 70,000 (0.5267)
= 36,869 (Dollars)
III. Total annualized cost of control is equal to the annual operating
cost plus the annualized capital cost.
Annualized Capital Cost = 0.133 X Installed Costs
89
-------
Assunptions:
1. Purchase and installation costs are depreciated over
fifteen (15) years.
2. The straight line method of depreciation (6 2/3% per
year) is used.
3. Other costs called capital charges are assumed to be
equal to the amount of depreciation. Therefore,
depreciation plus other capital charges amount to
13 1/3 percent of the initial capital costs of the
equipment.
Annualized Capital Costs = 0.133 (366,520) + 36,869
= 35,616 (Dollars)
90
-------
APPENDIX A-4
Maintenance Procedures
Maintenance Schedule
Spare Parts List
91
-------
MAECTMAKCE PROCEDURES
Inspection and maintenance of. bags, dampers, cylinders and actuators
can be made without shutting down the collector. A Basic Maintenance
schedule follows these procedures in Table A-l.
Switches in the damper control panel allow any individual cell to
be removed from the automatic cleanina cycle. By turning the selected
cell's toggle switch to the "OFF" position, its damper will remain in
the normal open position. By turning the toggle switch to "MANUAL", the
damper is moved to its reverse cleaning position. These switches may be
utilized even when the automatic cleaning cycle is in operation.
Isolating A Cell
When high negative static pressure inside the baghouse prevents
lifting of the hatch cover, turn the selected cell's toggle switch to
"MANUAL" and that cell will become pressurized allowing opening of the
hatch. Once the cell is open, turn switch to "OFF" position while
working in the cell.
Whenever work is to be done inside a cell, a plywood or metal plate
should be laid over the bags to:
- Prevent dislodging of the bags from the tube sheet.
- Prevent dropping of tools into the bags.
- Restrict ambient air from back flowing through the bags.
Bag Replacement
When replacing bags while the system remains in operation, it is
best to use several boards in the cell so that a minimum of bags are
exposed.
Step 1 - Remove Cage and Bag Together
Step 2 - Pull Bag From Cage
Step 3 - Insert Cage Into New Bag
Step 4 - Reinsert Cage
92
-------
- Viher. iaserting nesv bag, make certain pmp rings ?^ce in
place in the tube sheet and a total seal is obtained.
- When reinserting cage, maice certain cage reaches the
bottom of the bag.
The Cleaning Air System
The shock-drag cleaning system is working properly if (with all dampers
closed) the static pressure on the shock-drag plenum manometer reads + 8 -
10" W.G.
NOTE: - The cleaning cycle must be turned "OFF" to make this reading.
If this reading is low, the possible causes are:
- LDW air pressure at cylinders (must be 80 psi minimum) ;
if less than 80 psi - check regulator and lines for leakage
or freeze-up.
- Broken damper linkage (visually check damper positions) .
- Missing damper gasketing (visually check) .
- Shock-Drag drive worn (check for belt adjustment) .
- Damper obstructed from closing proper ly.
It is important that the shock-drag system be maintained, in proper
working order to insure tliat the pressure drop across the collector is
kept within design limits.
Shock Drag Fan and Motor
Check belts for wear and alignment. Check bearing for overheating
and lubrication.
Pneumatic Valves and Cylinders
Care must be taken to prevent freezing of the air lines and valves.
The air dryer and lubricator must also be maintained regularly or the
cleaning air system raay not function properly. Check for proper operation
of cleaning damper solenoid valves by activating then via manual override.
93
-------
The Cleaning Control Panel
The cleaning control panel is designed to control the shock-drag
cleaning of the bags by controlling the position of the individual cell
darpers. A damper's normal position is up, allowing system air to pass
and the bags to collect dust. Selectively, one cell at a tine, the
control panel activates a cell solenoid, which through a pneumatic
cylinder moves the cells damper to the down position. This stops the
system air flow and allows reverse air to flow into the cell and clean
the bags.
Two time delay relays provide variable control over the cleaning
time and the time between cleaning. TD1 controls the time a cell is
cleaning. TD2 controls the delay time between cells.
Control Panel Operation
Check for proper operation by scanning temperature and pressure
gauges for abnormal readings.
Hopper Dump Valve Operation
The double dump valve is checked manually to see that both gates open.
Should either one fail to open or close the difficulty lies in one of
two possibilities: either a weld or linkage has broken, in which case
re^welding v.culd be necessary; or, the shaft supporting plate could be
binding due to dirty parts in which case disassembly and cleaning would
be necessary.
94
-------
TABLE A-l
MAINTENANCE SCHEDULE
DRAIN AIR COMPRESSOR TANKS
ACTIVATE CLEANING DAMPER
SOLENOID VALVES VIA MANUAL
OVERRIDE TO CHECK FOR
PROPER OPERATION
CLEAN MAGNEHELIC LINES
CHECK HOPPER DUMP VALVE
OPERATION
REPLACE PLOTTER PAPER
DATE PLOTTER PAPER
GREASE CLEANING-AIR FANS
CHECK CONTROL PANEL OPERATION
INSPECT HARDWARE AND FITTINGS
CHECK BELT TENSION, CLEANING-AIR
AND MAIN FANS
CHANGE OIL IN AIR COMPRESSORS
VENT AIR FILTERS
CHECK AIR REGULATOR OPERATION
CLEAN CONTROL ROOM WORK AREA
DAILY WEEKLY
X
BI-WEEKLY
MONTHLY
BI-MONTHLY AS NECESSARY
X
X
X
X*
X
X
*TWO DAYS AFTER NEW BELTS, NORMAL OPERATION.
-------
SPARE PARTS LIST
This spare parts list is divided into three sections:
SECTION I - Parts located from the boiler stack to the baghouse
stack, excluding the control room control panel.
&SCTION II -- Pares located ir, the control reran control panel.
SECTION III - General parts (locally available).
96
-------
PARTS, SECTION I IM STOCK ORDER
Pneumatic Regulator X
Pneumatic Filter Assentoly X
Pneumatic Pressure Gauge (160 psi) X
Pneumatic Solenoid 12
(Cat. No. 8342A) 4-2; Volts 110/50
120/60; Pipe 1/4 Orifice 3/16;
Pressure Lt. Oil 100; Air Water 125;
Serial No. 5 40525 K7)
Pneumatic Air Restricter X
Limit Switch Assembly X
Inlet Damper Actuator Cylinder/
Repair Kit
Boiler Stack Cap Cylinder
Burner Control Valve Diaphrara
Burner Spark Plug
Bleed Air Cylinder/Repair Kit
Burner Gas Pressure Switches
Transmissometer, Moisture Absorbing
Capsules
Transntissonieter, Air Filters
Burner, Spark Plug Wire
97
-------
PARIS, SECTION I (continued) IN STOCK ORDER
Cleaning-Air Fans, Belts
Cleaning-Air Fans, Sheaves
Cleaning-Air Fans, Motor
Double Dump Valves, Cylinder Repair Kit
Double Dunp Valves, Linkage
System Fan, Belts
System Fans, Pillot Blocks/Bearing
Vortex Damper Cylinder, Repair Kit
Vortex Damper, Positioner
Air Compressor, Head Gaskets
Air Compressor, Filter
Air Compressor, Interoooler Safety Valve
Cleaning Damper Cylinder, Repair Kit
98
-------
PARTS, SECTION II
Part
Aux. Contacts (N.C.)
Aux. Contacts (No)
Sectional Terminal Block
Type AA Relay
Type M Relay
4 Pole Attachnent
Rear Pole (N.O.)
Variable Resistor
Adj. Lever
Overload Relay, Size 00
Limit Switch
Selector Switch
2 Pos., Spr. Rt.
Operator
Standard Button
Safety Breaker
Fuse Clip Kit
Std. Indicating Light
111. Pushbutton
Manufacturer
Cutler Hammer
Cutler Hammer
Cutler Hamer
Cutler Hamer
Cutler Hammer
Cutler Harrier
Clarostat
Cutler Hammer
Cutler Hammer
Cutler Hammer
Cutler Hammer
Cutler Hammer
Cutler Hammer
Cutler Hammer
Cutler Hammer
Cutler Hammer
Stock No.
C320KA2
C381TS
9575H2526-66
C381EF
D26MPR
A43
E50KL535
A10ANOB
E50AL1
T1371
Black T101
Red T102
Ch 130
C350KE23-6381
10250T185
10250T471
In Stock
6
6
(25) In 1 Box
1
3 Face Plates
8 Buchanan
2
2
1
1
6
15
4
6
1
1
3
2
99
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PARTS, SECTION III
Copper Tubing
Copper Fittings
Rubber Tubing
Rubber Clamps
Fasteners
Grease Fittings
Electrical Conduit, Flexible
Wiring, High Temperature
Electrical Fuses
Light Bulbs
Grease
Oil
Piping Cutout Valves
IN STOCK ORDER
100
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APPENDIX A-5
Particle Size Distribution (Microns) From
Andersen Tests - Teflon Felt
Gas-to-Cloth Ratio 4.5-6/1
Fractional Loading (Grains/dscf) From
Andersen Tests - Teflon Felt
Gas-to-Cloth Ratio 4.5-6/1
(Nozzle Wash Omitted From Stage 1)
Fractional Loading (Grains/dscf) From
Andersen Tests - Teflon Felt
Gas-to-Cloth Ratio 4.5-6/1
(Nozzle Wash Included in Stage 1)
Particle Size Distribution (Microns) From
Andersen Tests - Gore-Tex (With Some Woven Glass)
Gas-to-Cloth Ratio 4.5-6/1
Fractional loading (Grains/dscf) From
Andersen Tests - Gore-Tax (With Some Woven Glass)
Gas-to-Cloth Ratio 4.5-6/1
(No Nozzle Wash Recorded)
101
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Table A-2
o
N)
Particle Size Distribution (Microns) From Andersen Tests
Teflon Felt - Gas-to-Cloth Ratio 4.5-6/1
Run No.
14*
15*
16*
17*
18*
25
26
27
28
29
33
34
35
SI
>10.60
> 8.46
XL1.63
> 9.61
> 9.55
> 9.64
> 9.75
>8.87
>8.96
>8.92
>8.77
>8.79
> 8.80
S2
7.44
5.93
8.16
6.74
6.70
6.76
6.84
6.22
6.28
6.25
6.15
6.16
6.17
S3
4.58
3.64
5.03
4.15
4.12
4.16
4.21
3.82
3.86
3.84
3.78
3.79
3.80
S4
3.22
2.56
3.54
2.91
2.90
2.92
2.96
2.68
2.71
2.70
2.65
2.66
2.67
S5
2.10
1.66
2.31
1.89
1.88
1.90
1.92
1.74
1.76
1.75
1.72
1.73
1.73
S6
0.97
0.76
1.07
0.87
0.86
0.87
0.88
0.79
0.80
0.80
0.79
0.79
0.79
S7
0.58
0.45
0.65
0.52
0.51
0.52
0.52
0.47
0.47
0.47
0.47
0.47
0.47
S8
0.42
0.32
0.47
0.37
0.37
0.38
0.38
0.34
0.34
0.34
0.33
0.34
0.34
Back-Up
<0.42
<0.32
<0.47
<0.37
<0.37
<0.38
<0.38
<0.34
<0.34
<0.34
<0.33
<0.34
<0.34
Mean > 9.41 6.60 4.06 2.85 1.85 0.85 0.51 0.36 <0.36
*Nozzle Wash Not Recorded
-------
Table A-3
o
OJ
Run #
14
15
16
17
18
25
26
27
28
29
33
34
35
Total
Mean
Fractional Loading (Grains/dscf ) From Andersen Tests*
Teflon Felt - Gas-to-Cloth Ratio 4.5-6/1
SI
.00135
.00201
.00246
.00132
.00234
.00039
.00022
.00038
.00033
.00018
.00123
.00070
.00041
.01332
.00102
S2
.00070
.00107
.00086
.00087
.00154
.00024
.00023
.00026
.00022
.00020
.00088
.00046
.00053
.00806
.00062
S3
.00064
.00115
.00098
.00138
.00141
.00052
.00037
.00031
.00029
.00029
.00101
.00064
.00075
.00974
.00075
S4
.00090
.00069
.00095
.00066
.00110
.00049
.00062
.00020
.00032
.00020
.00077
.00073
.00046
.00809
.00062
S5
.00085
.00055
.00107
.00069
.00161
.00034
.00029
.00014
.00016
.00017
.00062
.00063
.00040
.00752
.00058
S6
.00074
.00038
.00074
.00048
.00066
.00029
.00031
.00015
.00018
.00016
.00041
.00041
.00038
.00529
.00041
S7
.00057
.00021
.00035
.00024
.00034
.00027
.00022
.00005
.00011
.00008
.00016
.00023
.00021
.00304
.00023
S8
.00033
.00007
.00009
.00011
.00018
.00020
.00009
.00009
.00011
.00005
.00009
.00016
.00013
.00170
.00013
Back-Up
.00082
.00015
.00064
.00023
.00027
.00017
.00013
.00019
.00009
.00005
.00023
.00024
.00015
.00336
.00026
Total
.00690
.00628
.00814
.00598
.00945
.00291
.00248
.00177
.00181
.00138
.00540
.00420
.00342
.06012
.00462
*Nozzle Wash Omitted From Stage 1
-------
Table A-4
Run #
25
26
27
28
29
33
34
35
Tbtal
Fractional Loading (Grains/dscf )
Teflon Felt - Gas-to-Cloth
SI
.06820
.00458
.03616
.01859
.02686
.05979
.04434
.07978
.33830
S2
.00024
.00023
.00026
.00022
.00020
.00088
.00046
.00053
.00302
S3
.00052
.00037
.00031
.00029
.00029
.00101
.00064
.00076
.00419
S4_
.00049
.00062
.00020
.00032
.00020
.00077
.00073
.00046
.00379
S5
.00034
.00029
.00014
.00016
.00017
.00062
.00063
.00040
.00275
from Andersen Tests*
Ratio 4.5-6/1
S6_
.00029
.00031
.00015
.00018
.00016
.00041
.00041
.00038
.00229
§7
.00027
.00022
.00005
.00011
.00008
.00016
.00023
.00021
.00133
S8
.00020
.00009
.00009
.00011
.00005
.00009
.00016
.00013
.00092
Back-Up
.00017
.00013
.00019
.00009
.00005
.00023
.00024
.00015
.00125
Total
.07072
.00684
.03755
.02007
.02806
.06396
.04784
.08280
.35784
Mean
.04229
.00038 .00052
.00047
.00034 .00029
.00017 .00012 .00016
.04474
*Nozzle Wash Included in Stage 1
-------
Table A-5
o
LTI
Run ft
8
10
19 -
Mean
Run #
8
10
19
Tbtal
Mean
Particle Size Distribution (Microns)
Gore-Tex (With Some
SI S2
>11.42 8.02
>11.34 7.96
> 8.54 5.99
>10.43 7.32
Fractional
S3
4.94
4.90
3.68
4.51
Loading
From Andersen Tests*
Woven Glass)- Gas-to-Cloth Ratio 4.5-6/1
S4_ §5
3.48 2.26
3.45 2.24
2.58 1.67
3.17 2.06
Table A-6
(Grains/DSCF) From
S6_ S7_
1.05 0.63
1.04 0.62
0.76 0.45
0.95 0.57
Andersen Tests*
S8_
0.46
0.45
0.32
0.41
Gore-Tex (With Some Woven Glass) - Gas-to-Cloth Ratio 4.5-6/1
SI S2
.00730 .00212
.00024 .00011
.00157 .00083
.00911 .00306
S3
.00213
.00008
.00127
.00348
S4 S5
.00110 .00118
.00005 .0
.00074 .00107
.00189 .00225
S6 S7 S8
.00125 .00068 .00034
.00005 .00006 .00004
.00124 .00133 .00068
.00254 .00207 .00106
Back-Up
.00064
.00020
.00083
.00167
Back-Up
<0.46
<0.45
<0.32
<0.41
.00304 .00102 .00116 .00063 .00075 .00085 .00069 .00035 .00056
Total
.01674
.00083
.00956
.02713
.00905
*Nozzle Wash Omitted From Stage 1
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/7-79-094
2.
3. RECIPIENT'S ACCESSION NO.
a. TITLE AND SUBTITLE Assessment of a High-velocity Fabric
Filtration System Used to Control Fly Ash Emissions
5. REPORT DATE
April 1979
,. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
J.D.McKenna, J.C.Mycock, K.D.Brandt, and
J.F.Szalav
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Enviro-Systems and Research, Inc.
2141 Patterson Avenue, SW
Roanoke, Virginia 24016
10. PROGRAM ELEMENT NO.
EHE 624
11. CONTRACT/GRANT NO.
68-02-2148
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
Final: 12/76-12/77
14. SPONSORING AGENCY CODE
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
i-RTP project officer is^JTH. Turner, MD-61, 919/541-2925
EPA/600/13
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The report gives results of a full-scale investigation (following a pilot
plant study) of applying high-velocity fabric filtration to coal-fired boiler fly ash con-
trol. Two filter systems were applied separately to two 60,000 Ib steam/hr coal-
fired boilers. Performance evaluated over a year included total mass removal effi-
ciency and fractional efficiencies. One filter system used Teflon felt as the filter
medium; the other used Gore-Tex, a PTFE laminate on PTFE woven backing. During
the year, a limited number of glass felt and woven glass bags were introduced into
the house containing Gore-Tex. Installed, operating, and annualized costs were
computed for five filter media (Teflon felt, Gore-Tex PTFE laminate, two weights of
woven glass, and a felted glass fabric) in a fabric filter systems capable of handling
70,000 acfm. The lighter weight woven glass fabric is the least expensive filter
medium overall and (assuming that a 4-year bag life is feasible) this makes fabric
filtration an economically attractive alternative to electrostatic precipitation. The
15 oz woven glass fabric had a projected annualized cost of $0. 36/acfm at an air-to-
cloth ratio of 5.8/1.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COS AT I Field/Group
Pollution
Filtration
Fabrics
Fly Ash
Coal
Boilers
Fluorocarbon Fibers
Glass Fibers
Felts
Woven Fabrics
Pollution Control
Stationary Sources
Fabric Filters
Bag Houses
High Velocity Tests
13B
07D
11E
21B
21D
13A
11B
8. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
114
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
106
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