United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S7-84-002 Feb. 1984
&ERA Project Summary
Fabric Filter System Study:
Third Annual Report
K. L Ladd, R. L Chambers, 0. C. Plunk, and S. L Kunka
The report gives results of the third
year of work (ending October 1, 1980)
on the fabric filter study being con-
ducted by Southwestern Public Service
Company for the USEPA. Results of the
special emissions testing program de-
monstrated that emissions were less
than the applicable 1971 EPA standard
of 0.1 lb/106 Btu* in all of the particu-
late emission tests. Fabric studies to
date show that several fabrics have a
potential 3-year baglife. The operation
and maintenance cost reported for the
third year of study is $434,800, or
$1.21 /yr/kW. Data analysis continued
through the third year. Information on
boiler 02 levels, air-to-cloth ratio, tem-
perature, system pressure drop, and
boiler load is being continuously logged.
This Project Summary was developed
by EPA's Industrial Environmental
Research Laboratory, Research Triangle
Park. NC, to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).
Introduction
'The third year of work on the fabric
filter system study being conducted by
Southwestern Public Service (SPS) for
the USEPA ended October 1, 1980. The
overall objective of this project is to make
a comprehensive study of a fabric filter
system used for particulate collection on
an electrical generating unit that utilizes
low sulfur, western coal.
SPS, an electric utility headquartered
in Amarillo, Texas, has a generating
*Non-metnc units are used here for the reader's
convenience Those more familiar with metric units
are asked to use the conversion factors at the end of
this summary.
capability of 3162 MW and serves cus-
tomers in Texas, Oklahoma, New Mexico,
and a small portion of Kansas. Harrington
Station, where the study is being per-
formed, is SPS's first coal-fired plant.
Located 8 miles northeast of Amarillo,
Harrington began operating in July 1976.
Three units are now on line, and construc-
tion is underway on SPS's second coal-
fired plant, Tolk Station. Tolk Station will
also be equipped with fabric filters.
Project activities during the third year
of the study included completion of the
special testing phase, analysis of fabric
testing results, observation of operation
and maintenance parameters, and con-
tinued data collection. The first and
second annual reports describe the objec-
tives and background of these project
activities.
The fabric filter system for Harrington
Unit 2 is a Wheelabrator-Frye, Inc.,
structural baghouse with deflate and
shake cleaning. It first went on line in
June 1 978. The baghouse consists of 28
compartments with 204 bags per com-
partment for a total of 5,712 bags; each
bag is 11.5 in. in diameter and 30 ft, 8.75
in. long at 60 Ib tension. The baghouse.
specified to operate at 1,650,000 acfm of
flue gas at 313°F, yielded an air-to-cloth
ratio of 3.15 to 1 (gross) or 3.4 to 1 (net).
Summary of Project Activities
1. Special testing of emissions was
performed four times during the
reporting period. Three of the emis-
sions tests were done by SPS, and
the fourth was performed jointly by
SPS and GCA. Particulate sizing at
the inlets and stack was attempted
during the SPS/GCAtest.
Particulate emissions from the
Unit 2 fabric filter system were less
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2.
than the applicable standard of 0.1
lb/106 Btu in all five of the panicu-
late emissions tests done to date.
Results (see Figure 1)showthatthe
average of each of the test series is
below both the 0.1 lb/106 Btu
standard and the new 0.03 lb/106
Btu standard.
Results of the special testing
program also showed that the stack
emissions of S02 agreed very well
with theoretically calculated emis-
sion levels based on fuel sulfur
content. The consistency between
the measured and theoretically
derived numbers also indicates that
EPA Method 6 is a reliable and
accurate measurement technique
for SO2 determination. The emis-
sions measured were in the range
of 0.78-1.01 lbSO2/106 Btu, demon-
strating that the existing EPA stan-
dard of 1.2 Ib SOz/106 Btu can be
met by burning coal with a sulfur
content lower than 0.5 percent.
In the summer of 1978 the Harring-
ton Unit 2 fabric filter system was
rebagged with a variety of fabrics to
allow a study of bag life and fabric
wear. Results of this program have
shown that several of the fabrics
0.05-r
0.04- •
ft)
a;
•
0.03- •
0.02- •
0.07 -
CCA
SPS/I
have a potential 3-year baglife. The
study also demonstrated that a
Teflon-coated 10-oz fabric outlasted
a heavier 14-oz acid-resistant fab-
ric. Studying the shaking motion of
these fabrics during cleaning re-
vealed that the stiffness of the 10-
oz fabric and the extra lubrication
offered by the Teflon coating con-
tribute to its longer baglife.
3. Operation and maintenance prob-
lems occurred during the third year
of the study in four main areas:
shaker tube bearings; sagging
shaker tube supports; damper drive
failure; and fabric failure.
The first two items are a result of
inherent design and, once cor-
rected, should not continue to be a
source of maintenance effort. The
third item, damper drive failures,
has been in large part due to
machining and lubrication prob-
lems. The dampers and drive mech-
anisms have been damaged at times
due to overdriving the mechanism
after a limit switch has failed.
The fourth item involved only a
few compartments containing a 14-
oz silicone/graphite-coated fabric
that failed prematurely. This experi-
SPS III
SPS SPS
GCA IV
Symbol
o Individual Test Run
« Average of Test Runs
100
200
300
400
500
600
700
ence, plus an analysis of the reac-|
tion of various fabrics to the shaking
motion and interpretation of fabric
testing data, indicates that the 14-
oz silicone/graphite-coated fabric
is not suitable for either Harrington
baghouse.
4. The operation and maintenance
cost reported for the third year of
study is $434,800, or $ 1.21 /yr/kW.
Thisfigure is somewhat higher than
the expected average because it
includes redesign and modifications
that will not have to be repeated
annually.
5. Data analysis continued through
the third year of study. Information
on boiler 62 levels, air-to-cloth ratio,
temperature, system pressure drop,
and boiler load is being continuously
logged at Harrington. Analyses have
shown that these variables are
highly correlated and that modeling
attempts will require sophisticated
statistical methods.
Conversion Factors
To convert the units in this summary to
metric equivalents, please use the fol-
lowing: '
Non-Metric
Multiplied
fay
Yields
Metric
Btu
°F
ft
ft3
in.
Ib
oz
9.48 x10~4
5/9(°F-32)
0.30
28.32
2.54
0.45
28.35
I
cm
kg
9
Days
Figure 1. Summary of paniculate testing.
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K. L. Ladd, R. L Chambers, 0. C. Plunk, and S. L. Kunka are with Southwestern
Public Service Company, Amarillo, TX 79170.
Dale L. Harmon is the EPA Project Officer (see below).
The complete report, entitled "Fabric Filter System Study: Third Annual Report,"
(Order No. PB 84-141 563; Cost: $10.00, subject to change) will be available
only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
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