EPA-600/2-76-042
February 1976
Environmental Protection Technology Series
PARTICULATE CONTROL MOBILE TEST UNITS:
First Year's Operation
Industrial Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into five series. These five broad
categories were established to facilitate further development and application of
environmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series describes research performed to develop and
demonstrate instrumentation, equipment, and methodology to repair or prevent
environmental degradation from point and non-point sources of pollution. This
work provides the new or improved technology required for the control and
treatment of pollution sources to meet environmental quality standards.
EPA REVIEW NOTICE
This report has been reviewed by the U.S. Environmental
Protection Agency, and approved for publication. Approval
does not signify that the contents necessarily reflect the
views and policy of the Agency, nor does mention of trade
names or commercial products constitute endorsement or
recommendation for use.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-76-042
February 1976
PARTICULATE CONTROL MOBILE TEST UNITS:
FIRST YEAR'S OPERATION
by
Robert E, Opferkuch
Monsanto Research Corporation
1515 Nicholas Road
Dayton, Ohio 45407
Contract No. 68-02-1816
ROAP No. 21ADM-034
Program Element No. 1AB012
EPA Project Officer: Dale L. Harmon
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
-------
ABSTRACT
This report summarizes the first year of operation of EPA-
owned mobile test units that are being used in the field
to study the applicability of different control methods to
the control of fine particulate emitted from a wide variety
of sources. Two mobile units are described: 1) a" fabric
filter (baghouse) and 2) a wet scrubber. The latter unit
includes two types of wet scrubbers: venturi and sieve
tray.
Results from baghouse tests on a coal-fired power plant indi-
cate suitability of a baghouse, with woven glass bags, for
control of dust from this type of source. Results from tests
on a pulp mill lime recovery kiln show high dust removal
efficiency, but the associated high moisture content of the
gases portends operating problems sufficient to indicate that
a baghouse would be unsuitable for control of dust from this
source.
Operation of the mobile scrubber unit during the year was
confined to startup testing and correction of mechanical and
operating difficulties.
11
-------
CONTENTS
No. Page
Abstract ii
List of Figures iv
List of Tables v
Acknowledgements vi
Sections
I Conclusions 1
II Recommendations 2
III Introduction and Objectives 3
IV Review of Operations 5
V References 49
VI Appendices
A. Baghouse Mechanical and Operational
Difficulties Encountered in the Field 50
B. Graphs of Percent Penetration by
Particle Size 54
111
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FIGURES
No. Page
1 Baghouse Unit on Site at Plymouth 7
2 Baghouse Unit on Site at Plymouth 8
3 External View of Mobile Scrubber Unit 30
4 Mobile Scrubber Flow Diagram 31
5 Mobile Scrubber Unit Process Area 32
6 Control Panel 33
7 Sieve Tray Column 36
8 Sieve Tray Characteristic Curves 37
9 Venturi Scrubber 38
10 Characteristic Curves-Small Throat Venturi 39
11 Characteristic Curves-Medium Throat Venturi 40
12 Characteristic Curves-Large Throat Venturi 41
13 Schematic Plan of Scrubber Unit 42
14 Dust Accumulation in Flow Nozzle 47
15 Revised Flow Schematic 48
16 Mud Deposit in Induction Fan Inlet 53
IV
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TABLES
Page
1 Proposed Test -Plan - Shake Mode 9
2 Proposed Test Plan - Pulse Mode 10
3 Proposed Test Plan - Reverse Mode 11
4 Actual Run Conditions 12
5 Total Mass Sample Results 14
6 Impactor Mass Results 16
7 Percent Penetration by Particle Size, Shake
Mode 18
8 Percent Penetration by Particle Size, Pulse
Mode 19
9 Percent Penetration by Particle Size, Reverse
Flow Mode - A/C Ratio, Glass Bag 20
10 Percent Penetration by Particle Size, Reverse
Flow Mode - Filtration Time, Glass Bag 21
ri Percent Penetration by Particle Size, Reverse
Flow Mode - A/C Ratio, Nomex Felt Bag 22
12 Percent Penetration by Particle Size, Reverse
Flow Mode - Filtration Time, Nomex Felt Bag 23
13 Mean Size (GMD), Microns 24
14 Revised Baghouse Testing Program 28
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ACKNOWLEDGEMENTS
The unstinting cooperation and help afforded the field test
crew by the management, and technical and operating person-
nel at Pennsylvania Power and Light Company, Shamokin- Dam,
Pa., generating station, and at Weyerhauser Corporation,
Plymouth, N. C., pulp mill, are acknowledged with sincere
thanks.
The Project Officer, Mr. Dale L. Harmon, provided valuable
assistance in negotiating entrance to the test sites, in
interfacing with the mobile unit fabrication contractors,
and in helpful suggestions regarding test plans.
VI
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I. CONCLUSIONS
Operating on a coal-fired power plant, baghouse cleaning-
mode/bag-type combinations can be ranked in descending order
of collection efficiency as follows:
1) Reverse clean - Nomex felt bag
2) Reverse clean - Glass bag
3) Shake clean - Nomex felt bag
4) Shake clean - Nomex woven bag
5) Pulse clean - Nomex felt bag
In general, the more efficient the cleaning mode, the poor-
er the filtration; or, the less a bag is cleaned, the better
it filters.
In general, the more difficult a bag is to clean, the better
it filters.
The smaller the fiber size in a bag fabric, the better its
retention of fine particles.
The more disoriented the bag fabric structure, e.g., felt
vs. woven, the more difficult the bag is to clean, conse-
quently the better it filters. This may include surface
disorientation, such as napping.
i
Although the relative humidity level has not been establi-
shed, it seems clear that for dust sources with associated
high moisture content, operating problems engendered by con-
densation will make baghouse control of dust impractical,
e.g., pulp mill lime recovery kiln.
-------
II. RECOMMENDATIONS
1. The need exists for review and evaluation of presently
used particulate sampling techniques in regard to the
usefulness of results obtained in relation to program
objectives.
2. It appears that repackaging and upgrading the baghouse
unit could improve the cost-effectiveness of the field
program.
3. A study of the present design and system configuration
of the scrubber unit could result in beneficial revisions
leading to improvement in cost-effectiveness of the field
program.
-------
III. INTRODUCTION AND OBJECTIVES
The purpose of this contract is to provide the operational
effort required to obtain field, laboratory, and pilot
plant test data from three types of EPA-owned equipment and
systems: 1) mobile test units; 2) an aerodynamic test
chamber; and 3) a model pilot SOX scrubber.
The mobile test units consist of truck-mounted items of
conventional dust collection equipment: fabric filter
(baghouse), venturi scrubber, sieve tray scrubber. A
fourth item, currently in design stage, will be an electro-
static precipitator. The main objective is to assess the
ease or difficulty associated with this type of equipment
in control of particulate of varying characteristics
obtained at different types of emission sources in the
field.
The wind-tunnel-like aerodynamic test chamber provides for
gas movement in a wide range of velocities at temperatures
from ambient to above 150°C and a broad spectrum of gas
composition and particulate loading. The objectives for
its use are calibration of fine particulate measurement
equipment, and characterization of the capabilities of com-
mercially available, pilot-scale, fine particulate control
equipment and devices.
The model pilot SOX scrubber consists of twin, 23-cm diame-
ter scrubbers and associated systems capable of several
types of scrubbing modes operating in parallel or series.
The objective of their operation is to find quick, easy,
inexpensive solutions to operating and technical problems
encountered in the development of full-size SOX scrubbing
systems.
The aerodynamic test chamber and model pilot scrubber sys-
tem are semi-permanent installations at the Environmental
Research Center at Research Triangle Park, N. C. Although
the mobile units use this location as a service base, the
majority of their operating time is spent in the field at
various plant sites about the country.
The three operational areas represent, to varying degrees,
different program interests, and up to now, different
groups or sections within the Industrial Environmental
Research Laboratory. The contractor's primary objective is
to fulfill the needs of each interest within the contract
scope. Thus, his involvement varies a little in each opera-
tional area. For example, in the areas of the aerodynamic
-------
test chamber and pilot SOX scrubbers, program and test
planning, and interpretation of results activities are
mainly conducted by EPA personnel. The contractor schedules
and executes the test plans per specified conditions, and
collects and reduces data to usable form. The nature of
the current program, especially the pilot SOX scrubber pro-
gram, dictates this type of relationship. On the other
hand, in the mobile test unit area, the contractor is also
largely responsible for developing the test plans and inter-
preting the results obtained.
This report summarizes operation of the mobile baghouse and
scrubber units during the first contract year. The baghouse
unit operated in the field evaluation program essentially
the entire year. Delayed receipt of the scrubber unit,
occasioned by slower than expected delivery of materials
during fabrication, plus mechanical difficulties that
emerged during startup testing have frustrated attempts to
start the field evaluation program with this unit.
-------
IV. REVIEW OF OPERATIONS
BAGHOUSE UNIT
Background
The mobile fabric filter system (baghouse unit) was designed
and fabricated by GCA/Technology Division, Bedford, Mass.
The unit, mounted on a 1360 kg truck, is described at length
in GCA reports (Ref. 1, 2). Briefly, it has the following
capabilities:
Filtration can be conducted at cloth velocities as
high as 0.102 m/s with a pressure differential up to
51 cm of water and at gas temperatures up to 288°C.
The mobile system can be adapted to cleaning by
mechanical shaking, pulse jet, or low pressure
reverse flow, with cleaning parameters varied over
broad ranges.
The system can be operated in a series filtration
mode.
One to seven filter bags of any media, 1.22 to 3.05
meters long and up to 30 cm in diameter may be used.
Automatic instruments and controls permit 24-hour
operation of the system.
After brief field tests, the unit was delivered to present
contractor personnel for use in a large field testing pro-
gram for the Industrial Environmental Research Laboratory
of EPA.
For several reasons, the baghouse unit, as received,
required preliminary "dry run" testing at the RTP Environ-
mental Research Center, and intensive shakedown tests in
the field under severe conditions. The dry run tests at
RTP were directed at operational check of system components
and training of new operators.
Following this, the unit was given intensive shakedown tests
in the field on a pulp mill lime recovery kiln. After a
brief return to RTP for refurbishing, the unit was taken to
Sunbury, Pa., for tests on Pennsylvania Power and Light
Company's Shamokin Dam, coal fired, generating station.
-------
On completion of these tests, about two months were required
to refurbish the unit and sample trains, after which the
unit was placed at a lime recovery kiln at Weyerhauser
Corporation's pulp mill in Plymouth, N. C. At this writing,
the unit is in final phases of testing on the lime kiln and
will next move to a recovery furnace at the same plant.
Shakedown Tests
The dry run tests at RTF revealed a number of operational
deficiencies, none of which appeared particularly serious.
While these deficiencies were readily corrected, the ques-
tion persisted of performance reliability and durability
under severe, protracted field conditions, since all sys-
tems operating in an integrated mode could not be checked
in dry run tests.
For field shakedown testing, the unit was attached to a pulp
mill lime recovery kiln. A host of difficulties ensued.
These are noted, along with remedial actions, in Appendix A,
which also lists operational difficulties encountered subse-
quently at Sunbury and on return to Plymouth. Figures 1
and 2 show the unit on site at Plymouth.
Sunbury Tests
Details of testing at Sunbury were reported in a special
technical operations report for that site, and operational
difficulties, as noted above, appear in Appendix A.
Three types of bags and three cleaning modes were tested:
Bag Type: Glass
Nomex Woven
Nomex Felted
Cleaning Mode: Shake
Pulse
Reverse
Test plans proposed for each cleaning mode with each bag type
are shown in Tables 1-3. Time restraints imposed by
lengthy sampling periods and availability of the test site
resulted in adoption of the compromise test plan shown in
Table 4. Throughout the tables and graphs that follow,
-------
r*w|
Figure 1. Baghouse Unit on Site
at Plymouth, N.C.
-------
Figure 2. Baghouse Unit on Site
at Plymouth, N.C.
3
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Table 1. PROPOSED TEST PLAN-
SHAKE MODE
Series 1
Variable: Air/Cloth ratio (A/C)
A/C range: 0.005 - 0.041 m/s
Test values: 0.005, 0.010, 0.020, 0.030, 0.041 m/s
All other parameters at standard conditions.
Series 2
Variable: Filtration period
Test values: 10, 20, 30 min
Use optimum A/C determined above. All other parameters
at standard conditions.
Series 3
Variable: Cleaning (shake) period
Test values: 5, 10, 20, 30, 60 sec
Use optimum A/C and filtration period determined above.
All other parameters at standard conditions.
Standard Conditions
Filtration period 20 min
1st pause 10 sec
Cleaning period 10 sec
2nd pause 30 sec
Shake frequency 7 cps
Amplitude 2.22 cm
Shaker-arm acceleration 4.4g's
Bag tension 0.682 kg
A/C 0.02 m/s
9
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Table 2. PROPOSED TEST PLAN-
PULSE MODE
Series 1
Variable: Air/Cloth ratio (A/C)
A/C range: 0.010 - 0.102 m/s
Test values: 0.010, 0.020, 0.030, 0.041, 0.0508, 0.076,
0.102 m/s
All other parameters at standard conditions.
Series 2
Variable: Pulse jet pressure
Test values: (2.76, 3.45, 4.14, 4.83, 5.52, 6.21) x 105 Pa
Use optimum A/C determined above. All other parameters at
standard conditions.
Series 3
Variable: Pulse interval
Test values: 15, 30, 60, 90, 120 sec
Use optimum A/C and pulse jet pressure determined above.
All other parameters at standard conditions.
Standard Conditions
Pulse interval 60 sec
Pulse duration 0.10 sec
Pulse jet pressure 4.14 x 10^ Pa
A/C 0.020 m/s
10
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Table 3. PROPOSED TEST PLAN-
REVERSE MODE
Series 1
Variable: Air/Cloth ratio (A/C)
A/C range: 0.005 - 0.041 m/s
Test values: 0.005, 0.010, 0.020, 0.030, 0.041 m/s
All other parameters at standard conditions.
Series 2
Variable: Filtration period
Test values: 20, 30, 40 min
Use optimum A/C determined above. All other parameters
at standard conditions.
Series 3
Variable: Cleaning (reverse) period
Test values: 5, 10, 20, 20, 60 sec
Use optimum A/C and filtration period determined above,
All other parameters at standard conditions.
Standard Conditions
Filtration period 30 min
1st pause 10 sec
Cleaning period 10 sec
2nd pause 30 sec
Bag tension 0.682 kg
A/C 0.02 m/s
R. F. air rate 0.047 m^
11
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Table 4. ACTUAL RUN CONDITIONS
SHAKE MODE
Filtration period 20 min.
1st pause 10 sec
Cleaning period 10 sec
2nd pause 30 sec
Shake frequency 7 cps
Amplitude 2.22 cm
Shaker-arm acceleration 4.4g's
Bag tension 0.682 kg
A/C 0.010, 0.015,
0.020 m/s
PULSE MODE
Pulse interval 1,2, 3 min
Pulse duration 0.10 sec
Pulse jet pressure 4.14 x 10^ pa
A/C 0.020, 0.031
(max.) m/s
REVERSE MODE
Filtration period 30, 40, 50 min
1st pause 30 sec
Cleaning period 20 sec
2nd pause 30 sec
Bag tension 0.682 kg
A/C 0.010, 0.015,
0.020 m/s
R. F. air rate 0.045 m^/s
12
-------
sample runs are identified by a code composed of the
following:
First letter = Cleaning Mode: S - Shake
P - Pulse
R - Reverse
Second letter = Bag Type: G - Glass
NW - Nomex Woven
NF - Nomex Felted
First Number = A/C ratio, fpm (x 5.08 x 10- = m/sec)
Second Number = Filtration Period, min, for shake and
reverse
= Pulse interval, sec, for pulse
Within the reliability of the sampling techniques, test
data precision was generally good. Overall collection
efficiency was derived from two sources: total mass samp-
ler, and impactor total mass. Results from each source are
shown in Tables 5 and 6. Of these, the total mass sampler
results are believed to be more accurate since there are
some known loss errors associated with the impactor total
mass results. By either method, however, efficiency appears
to be quite good.
The data and discussion related to size distribution, too
voluminous for this report, are summarized in Tables 7
through 12 in the form of percent penetration by particle
size, grouped to show, by cleaning mode and bag type:
-Effect of A/C ratio,
-Effect of pulse interval, and
-Effect of filtration period
on penetration by particle size. This information is shown
graphically in Appendix B.
The mean particle size for each sample run is shown in
Table 13, wherein also are the arithmetic averages of
grouped inlet values and outlet values for each operating
mode, and ultimately, the overall average size (geometric
13
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Table 5. TOTAL MASS SAMPLE RESULTS
Mass Loading,
Percent
Run
S-G-2-20
S-G-3-20
S-G-4-20
Average
S-NW-2-20
S-NW-3-20
S-NW-4-20
Average
S-NF-2-20
S-NF-3-20
S-NF-4-20
Average
P-NF-4-1
P-NF-6.2-1
P-NF-6 . 2-2
P-NF-6. 2 -3
Average
R-G-2-30
R-G-3-30
R-G-4-30
R-G-4-40
R-G-4-30
Average
2
3
4
5
1
1
4
4
5
3
7
6
7
3
3
3
1
1
In
503
108
030
3 213
828
246
898
2 991
466
818
299
4 862
858
855
069
525
6 325
616
197
075
509
960
2 672
Out
93
1
207
100
14
1
53
23
1
1
1
1
2
35
119
77
58
21
9
8
13
Col.
96
99
94
99
99
97
99
99
99
99
99
98
98
99
99
99
-
-
Eff . Penetration
.30
.97
.88
97.05
.76
.89
.23
98.96
.71
.98
.98
99.89
.94
.56
.03
.97
99.13
.42
.73
.74
99.63
3
0
5
0
0
2
0
0
0
0
0
1
1
0
0
0
.70
.03
.12
2
.24
.11
.77
1
.28
.02
.02
0
.06
.44
.97
.03
0
.58
.27
.26
0
.95
.04
.11
.88
.37
14
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Table 5. TOTAL MASS SAMPLE RESULTS (Confd)
Mass Loading,
Percent
Run
R-NF-2-30
R-NF-3-30
R-NF-4-30
R-NF-3-40
R-NF-3-50
R-NF-3-30
Average
3
4
4
3
4
2
In
902
122
282
833
889
352
3 896
Out
1
5
1
3
1
2
Col.
99
99
99
-
99
99
Eff. .Penetration
.99
.88
.99
.95
.95
99.95
0.01
0.12
0.01
0.05
0.05
0.05
Average
3 969
31
99.18
0.82
15
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Table 6. IMPACTOR MASS RESULTS
Mass Loading, mg/rn^
Percent
Run
S-G-2-20
S-G-3-20
S-G-4-20
Average
S-NW-2-20'
S-NW-3-20
S-NW-4-20
Average
S-NF-2-20
S-NF-3-20
S-NF-4-20
Average
P-NF-4-1
P-NF-6.2-1
P-NF-6.2-2
P-NF-6.2-3
Average
R-G-2-30
R-G-3-30
R-G-4-30
R-G-4-40
R-G-4-30
Average
3
2
8
5
1
2
6
2
4
1
1
7
1
1
2
_
4
4
1
2
1
1
1
1
1
In
870
702
794
5 130
473
695
290
3 160
549
885
534
4 649
305
053
351
580
786
725
__
2 634
534
328
763
588
969
718
168
214
985
168
2 129
Out
4
4
8
5
2
1
2
2
3
1
33
2
2
67
86
28
1
1
1
1
1
1
3
4
1
Col.
99
99
99
99
99
99
99
99
97
99
99
_
99
99
99
99
99
99
99
99
Eff. Penetration
.92
.79
.68
99.80
.96
.97
.96
99.96
.77
.87
.87
.89
.93
__
99.47
.99
.99
.99
.99
.97
.91
.74
.66
99.91
0
0
0
0
0
0
0
0
2
0
0
0
0
0
0
0
0
0
0
.076
.211
.325
0.
.036
.035
.035
0.
.233
.134
.13
.110
.066
___
0.
.0025
.0021
.013
.007
.031
.089
.265
.345
0.
204
035
535
094
16
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Table 6. IMPACTOR MASS RESULTS (Cont'd)
Mass Loading,
Percent
Run
R-NF-2-30
R-NF-3-30
R-NF-4-30
R-NF-3-40
R-NF-3-50
R-NF-3-40
Average
Average
1
2
1
1
5
2
1
In
557
061
985
756
733
557
809
313
290
031
962
1 718
2 634
Out
1
1
4
1
1
1
1
. 1
1
1
1
1
7
Col.
99
99
99
99
99
99
99
99
99
99
99
Eff . Penetration
.98
.98
.61
.83
.92
.95
.99
.99
.99
.94
.93
99.92
99.83
0
0
0
0
0
0
0
0
0
0
0
.019
.020
.391
.166
.079
.047
.006
.003
.007
.058
.065
0
0
.078
.167
17
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Table 7. PERCENT PENETRATION BY PARTICLE SIZE, SHAKE MODE
Geo. Mean Dia,
30
10
8
6
5
4
3
2
£ i
0.7
AVG.
S-NW-2
01 Q q
. i y j
0.511
0.383
0.158
0.100
0.210
0.166
0.191
0.177
0.267
n o/ini
S-NW-3
U . Ufl^o
0.0825
0.0833
0.0954
0.0981
0.156
0.259
0.318
0.0956
0.0714
n oiio
S-NW-4
OA Q~l
. ft OX
0.629
0.818
0.591
0.400
0.183
0.167
0.221
0.318
0.271
n TQQQ
Avg.
0.408
0.428
0.281
0.199
0.183
0.197
0.243
0.197
0.203
S-NF-2
OC C A
. D D*i
0.967
1.030
0.822
0.256
0.153
0.0643
0.0826
0.216
1.390
n qq^a
S-NF-3
004 c
. Jft O
1.500
1.520
0.304
0.215
0.135
0.0275
0.0073
0.015
0.0615
n A^^Z
S-NF-4
On"? c
. U / -D
0.0261
0.0250
0.0400
0.100
0.0312
0.0200
0.0483
0.0261
0.0944
n 1 1 Af\
Avg.
0.831
0.858
0.509
0.190
0.106
0.037
0.0597
0.0857
0.515
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Table 8. PERCENT PENETRATION BY PARTICLE SIZE, PULSE MODE
P-NF-4-1 P-NF-62-1 P-NF-6.2-2 P-NF-6.2-3
Geo. Mean Dia.
30
10
8
6
5
4
3
2
1
0.7
AVG.
AVG.
Run 1
04 fie
. 4 UD
00 r\c
. £ UO
2.00
1.250
0.815
0.682
0.262
0.155
0.121
0.166
0.629
0.
Run 2
Ono Q
. Uo y
1 no
-L . J. J
1.16
2.75
2.35
0.80
0.10
0.041
0.126
0.40
0.984
807
Run 1
0(\~l £>
. U / O
1 "5Q
JL . jy
5.67
11.30
12.30
4.55
1.21
0.95
11.4
3.65
5.82
1
Run 2
OQA
yt
2 en
. DU
16.30
28.60
32.60
32.80
9.50
4.10
5.29
1.14
14.75
0.3
Run 1
Onfi*?
. u u /
Om c.
. U J- D
0.031
0.024
0.014
0.013
0.180
0.371
0.191
0.139
0.109
0
Run 2
0.001
0.003
0.007
0.072
0.137
0.343
0.142
0.090
0.0994
.104
Run 1
o c c
J D D
i fin
-L . U U
1.27
0.95
6.20
5.82
4.27
8.57
4.89
1.33
3.811
4
Run 2
9 cp
£. . J O
1.98
3.55
3.98
4.42
5.24
10.90
4.04
1.53
4.455
.13
Avg.
1 1 fiO
_L . -L U J
3.748
6.053
7.283
6.226
2.612
3.179
3.275
1.056
-------
Table 9, PERCENT' PENETRATION BY PARTICLE SIZE, REVERSE FLOW MODE
Effect of A/C Ratio
Glass Bag
Geo. Mean Dia
30
10
8
6
5
4
to .,
0 -5
2
1
0.7
R-G-2-30
Run 1 Run 2
0.00294 0.00286
0.00476 0.00333
0.00476
0.00476
0.00434
0.0025
0.00115
0.00015
0.024
0.0472
0.00303
0.00217
0.00135
0.00059
0.00077
0.00268
0.0647
0.052
R-G-3-30
Run 1 Run 2
0.024 0.0106
0.115 0.0250
0.0836
0.0261
0.0175
0.0128
0.0116
0.0187
0.0182
0.0208
0.138
0.0769
0.026
0.0111
0.010
0.0126
0.00603
0.012
Run 1
0.188
0.469
0.75
0.159
0.073
0.180
0.0279
0.0105
0.0176
0.0414
R-G-4-30
Run 2 Run 3
0.0857 0.379
0.125 0.524
0.183
0.0695
0.073
0.360
0.100
0.0127
0.0241
0.048
0.548
0.246
0.354
0.487
0.486
0.217
1.500
0.327
Run 4
0.250
0.167
0.139
0.176
0.194
0.122
0.170
0.189
AVG.
AVG.
0.0104 0.0145
0.0125
0.0360 0.0353
0.0357
0.2129
0.1201
0.1696
0.1759
-------
Geo,
Table 10. PERCENT PENETRATION BY PARTICLE SIZE, REVERSE FLOW MODE
Effect of Filtration Time
Glass Bag
Mean Dia.
30
10
8
6
5
4
3
2
1
0.7
AVG.
AVG.
Run 1
0.188
0.469
0.75
0.159
0.073
0.180
0.0279
0.0105
0.0176
0.0414
0.2129
R-G-4-30
Run 2
0.0857
0.125
0.183
0.0695
0.073
0.36
0.100
0.0127
0.0241
0.048
0.1201
0.1696
Run 3
0.250
0.167
0.139
0.176
0.194
0.122
0.17
0.189
0.1759
R-G-4-4
Run 1
0.282
0.0795
0.479
0.00447
0.00434
0.00444
0.00432
0.00250
0.0938
0.417
0.0731
0.0929
0
Run 2
0.480
0.479
0.319
0.021
0.0133
0.00833
0.00432
0.00178
0.0444
0.0469
0.1126
-------
Table 11. PERCENT PENETRATION BY PARTICLE SIZE, REVERSE FLOW MODE
Effect of A/C Ratio
Nomex Felt Bag
R-NF-2-30
Geo.
to
Mean Dia.
30
10
8
6
5
4
3
2
1
0.7
Run 1
0.0485
0.214
0.0388
0.00571
0.00408
0.00354
0.00457
0.0112
0.0157
0.0222
Run 2
0.1458
0.143
0.187
0.333
0.184
0.0291
0.0149
0.0384
0.008
0.008
Run 1
7.83
4.56
4.09
2.45
1.75
0.106
0.0621
0.00917
0.0359
0.0727
R-NF-3-30
Run 2
0.0871
0.700
0.357
0.0111
0.0231
0.0426
0.0294
0.00733
0.291
0.826
Run 3
0.197
0.429
0.634
0.060
0.0338
0.0195
0.0259
0.0952
0.0143
0.00526
R-NF-4-30
Run 1
0.0633
0.0567
0.0263
0.0486
0.0771
0.015
0.0854
0.0657
Run 2
0.00344
0.00345
0.00351
0.00368
0.0260
0.0214
0.0310
0.005
AVG.
AVG.
0.0355 0.105
0.070
0.254 0.146
0.200
0.0548 0.0122
0,0335
-------
Table 12. PERCENT PENETRATION BY PARTICLE SIZE, REVERSE FLOW MODE
Effect of Filtration Time
Nomex Felt Bag
Geo,
10
.ean Dia,
30
10
8
6
5
4
3
2
1
.7
Run 1
7.83
4.56
4.09
2.45
1.75
0.106
0.0621
0.00917
0.0359
0.0727
R-NF-3-30
Run 2
0.871
0.700
0.357
0.0111
0.0231
0.0426
0.0294
0.00733
0.291
0.826
Run 3
0.197
0.429
0.634
0.060
0.0338
0.0195
0.0259
0.0952
0.0143
0.00526
R-NF-3-40
Run 1 Run 2
0.00862
0.00522
0.00500
0.00449
0.00333
0.00217
0.0230
0.0970
0.0109
0.0225
0.0250
0.0228
0.0088
0.00323
0.00667
0.0840
R-NF-3-50
Run 1 Run 2
0.140 0.236
0.274 0.0752
0.125 0.0666
0.0363
0.0277
0.0456
0.0138
0.0074
0.0162
0.00704
0.0276
0.0241
0.0233
0.015
0.012
0.010
0.008
AVG.
AVG.
0.254
0.200
0.1463
0.0186 0.0230
0.0208
0.0614 0.0567
0.0591
-------
Table 13. MEAN SIZE (GMD), MICRONS
per Run Average
Run IN OUT IN OUT
S-G-2-20
S-G-3-20
S-G-4-20
S-NW-2-20
S-NW-3-20
S-NW-4-20
S-NF-2-20
S-NF-3-20
S-NF-4-20
P-NF-4-1
P-NF-6.2-1
P-NF-6.2-2
P-NF-6.2-3
R-G-2-30
R-G-3-30
R-G-4-30
R-G-4-40
R-NF-2-30
R-NF-3-30
10.1
17.7
27.6
6.98
8.13
55.7
44.7
6.51
9.95
9.45
91.9
15.6
7.54
5.11
^ *""" *"* "^ ^
31.4
29.6
19.6
20.1
13.3
15.6
23.1
6.87
9.23
30.2
56.5
10.6
17.75
7.82
9.66
11.65
7.87
12.7
19.6
10.3
6.82
2.89
3.83
3.89
2.21
2.13
3ft\
. ou
41 Q
. -L y
2.74
3.55
9.00
6.97
8.53
11.58
9.29
18.6
7.24
16.1
20.5
17.7
10.1
10.1
17.7
27.6
6.98
8.13
55.7
44.7
6.51
9.70
53.7
6.32
30.5
19.9
14.0
8.08
43.4
12.6
9.66
11.65
7.87
12.7
19.6
10.3
4.85
3.86
2.17
3p Q
. o y
3.14
7.99
9.80
18.6
11.7
16.1
24
-------
Table 13 (cont'd)
R-NF-4-30 3.85 9.02
3.21 11.9 3.53- 10.5
R-NF-3-40 5.45 9.22
47.3 9.88 26.3 9.55
R-NF-3-50 36.6 12.3
16.2 14.4 26.4 13.3
Overall Average 22.6 9.85
25
-------
mean diameter) for inlet and outlet.
Analysis of size distribution results leads to the following
general statements:
Based on collection efficiency of particles 5 ju and
less in size, cleaning-mode/bag-type combinations
can be ranked in descending order of collection
efficiency as follows:
1) Reverse clean - Nomex felt bag
2) Reverse clean - glass bag
3) Shake clean - Nomex felt bag
4) Shake clean - Nomex woven bag
5) Pulse clean - Nomex felt bag
The more efficient the cleaning mode, the poorer" the
filtration, or, inversely, the less the bag is
cleaned, the better it filters. Going from poorest
to most efficient cleaning mode the ranking is:
reverse, shake, pulse.
The more difficult a bag is to clean, the better it
filters. The significant comparison here is between
Nomex felt and Nomex woven in shake mode.
Bag-fabric characteristics have a strong effect on
filtration efficiency.
Fiber size - It is understood that the smaller the
fiber diameter in a bag fabric, the greater the
retention of small particles. In the present case,
an interesting comparison is found between glass
fabric and Nomex felt, in reverse cleaning mode.
The glass fabric is woven, 200 g/aq m with air
permeability of 40 cfm/sq ft. The Nomex felt is
332 g/sq m with permeability of 40 cfm/sq ft.
Strictly on this comparison, a considerable dif-
ference in performance would be expected. The glass
bag, being more open and lighter in weight, should
perform worse than the Nomex felt bag, yet data
obtained suggest almost equal performance. Assuming
both fabrics are made of 3-denier fiber, the Nomex
fiber diameter would be about 1.5 times larger than
the glass fiber due to the difference in density.
26
-------
This disparity will be even greater if the glass
fiber is less than 3-denier, i.e., the glass fiber
will be even smaller in diameter.
Fabric structure - It is not surprising in present
comparisons that the Nomex felt bag outperforms the
Nomex woven bag. Fiber size in the two fabrics is
likely the same, 3-denier. The woven bag is light,
107 g/sq m, but tightly woven, with permeability
of 18 cfm/sq ft. Relative to the woven bag, however,
air passages in the felt bag are tortuous, provid-
ing frequent opportunity for particle-fiber col-
lision. It is this same character of the felt bag
that makes it more difficult to clean.
Though far from rigorous, these statements appear to coin-
cide with reality, i.e., at Sunbury, a full scale baghouse
using glass bags and reverse cleaning mode is in satisfac-
tory operation on the generating station. The bag ranking
shown above indicates Nomex felt bags may be more efficient
but their higher cost for an incremental improvement is
unjustifiable.
Plymouth Tests
In view of the time restraints imposed on the program by
the lengthy sampling period required to collect a reliable
amount of sample in the effluent position, the test plan
for Plymouth was again modified. Overall efficiency from
total mass sampling was adopted as the prime criterion for
evaluating baghouse response to changing test conditions.
For each bag/cleaning-mode condition showing best efficiency,
size distribution measurements would be made. This approach
has the beneficial effect of reducing the time consumed in
sampling. The test plan for Plymouth is shown in Table 14.
Early data from Plymouth indicate high collection efficien-
cies. This is supported by the following. While dust load-
ings at Plymouth are somewhat higher than those at Sunbury,
it is necessary to sample the effluent 7-8 hours, com-
pared with 3-4 hours at Sunbury, to collect a reliably
measurable amount of mass.
It is not sufficient, however, to consider collection
efficiency alone as a basis for baghouse application to a
pulp mill lime recovery kiln. The high temperature, 204° -
260°C, can be accommodated by glass bags but the high mois-
ture content, over 20%, would be anathema to practical
27
-------
Table 14. REVISED BAGHOUSE TESTING PROGRAM
(Lime Kiln/Recovery Furnace)
Weyerhauser Pulp Mill, Plymouth, N. C.
CLEANING
MODE
SHAKE
REVERSE
A/C
RATIO
Low High
3
3
5
3
3
3
3
5
FILTERING
TIME (min)
Low High
30
50
30
30
30
50
30
30
CLEANING
TIME (sec)
Low
5
5
5
5
5
5
High
20
20
28
-------
operation of the system. A costly and seldom used preheat
and bypass system would be required at each startup of the
baghouse, and insulation requirements would be extreme to
prevent condensation and deposition of mud on the bags and
throughout the system.
SCRUBBER UNIT
Background
The mobile scrubber unit was designed and fabricated by the
Detection Branch, Chemical and Biological Sciences Division
of the Naval Surface Weapons Center (NSWC), Dahlgren, Va.,
under Project Order No. 4-0105-(NOL)/EPA - 1AG -133 (D)
Task 2. On completion of construction and brief equipment
check-out by NSWC, the present contractor received the unit
for the Industrial Environmental Research Laboratory on
December 16, 1974 and placed it on site at Pennsylvania
Power and Light Company's generating station at Sunbury,
Pa., for initial field shakedown testing. Shortly after
startup of the unit at Sunbury, the induction fans failed
and NSWC retrieved the unit to determine the cause of fail-
ure and to repair the fans.
On completion of repairs and minor modifications, the unit
was returned to IERL (via its contractor) and taken to the
Research Triangle Park for extensive shakedown tests under
simulated field conditions. Following this, the unit was
taken to Weyerhauser Corporation's pulp mill at Plymouth,
N. C. and hooked up to a lime recovery kiln for execution
of a test plan for evaluating dust control efficiency of
the two types of scrubbers involved. At this writing, test-
ing has not begun, pending completion of baghouse unit tests.
Unit Description
The scrubber unit consists of a venturi scrubber and a
sieve tray scrubber, together with supporting functional
systems housed in the 13.72-meter trailer shown in Figure 3.
A schematic process flow diagram is shown in Figure 4. The
system permits operation of either the venturi scrubber or
sieve tray scrubber at maximum nominal rate of 0.24 m^/s
gas flow rate. A presaturator is intended to cool and satu-
rate high temperature gas entering to protect heat sensitive
elements ahead of the scrubbers and minimize temperature
29
-------
Figure 3. External View of
Mobile Scrubber Unit
-------
ICRUMEO
U* CUT
Ifl .g -:
THROTTLE VALVE
KJTTERFLY VALVE
MOTON MIVEM
BUTTERFLY VALVE
SOLE MOID VALVE
CHECK VALVE
FftOCEU IK9TI
Figure 4. Mobile Scrubber
Flow Diagram
31
-------
Figure 5. Mobile Scrubber Unit Process Area
32
-------
Figure 6. Control Panel
-------
and evaporation of recirculating scrubber liquid when in
closed loop mode. The presaturator can be bypassed when
desired.
The demister is intended to collect both liquid and solid
entrained in the scrubber exhaust, thus affording some pro-
tection to the high speed induction fans. A solids filter
permits removal and disposal of particulate collected by
the scrubbers when in closed loop circulation mode. In open
loop mode, the filter minimizes solids load on the available
external drainage system.
The gas duct entering the unit is equipped with in-line
electric heaters to minimize gas temperature loss between
the source and the scrubbers. A flow nozzle in the duct
permits measurement of the gas rate to the scrubbers.
Liquid from all components noted flows to a sump tank, to
the solids filter, to the supply tank, and then is recircu-
lated through the scrubbers.
Figure 5 is a view of the process area looking forward in
the trailer. In the foreground, on the floor, are the
induction fans. Above them, near the ceiling, is the
demister. Just beyond the fans is the venturi scrubber.
Beyond this, and partially obscured, is the sieve tray
scrubber. Forwardmost, just left of the control room door,
is the presaturator. Figure 6 is a view of the control
room panel.
Sieve Tray Scrubber
The sieve tray scrubber is a four-tray column in which
liquid, fed to the downcomers in the top section, flows
across each tray, over a weir into downcomers to the sec-
tion below, collecting finally in a level-controlled bot-
toms chamber from which it drains to the sump tank.
Gas enters the bottom chamber, flows up through successive
trays and discharges from the top scrubbing section. The
column is shown in Figure 7.
Three sets of sieve trays, each with the same total open
area, have hole sizes of 0.32 cm, 0.48 cm, and 0.64 cm,
respectively. Since the liquid level on each tray, con-
trolled by the fixed height of the inlet/outlet weirs, is
nominally constant, regardless of liquid flow rate, and
since the total open area of the three sets of sieve trays
34
-------
is constant, pressure drop across the sieve tray column is
mainly a function of the total gas flow rate and is rela-
tively independent of tray hole size and liquid flow rate.
This relationship is shown in the characteristic curves in
Figure 8.
Venturi Scrubber
The venturi scrubber consists simply of a venturi throat
section attached to a cyclone as shown in Figure 9. Scrub-
bing liquid is added to the throat about two inches below
the throat entrance. Three interchangeable throat sections,
each 30.5 cm long, have diameters 3.5 cm, 6.0 cm, and 8.5
cm. As expected, characteristic curves for each venturi
throat, Figures 10 through 12, show pressure drop to be
significantly dependent upon both gas and liquid flow rates.
Sunbury Shakedown Tests
The scrubber unit was taken, as received, directly from
NSWC at Dahlgren, Va., to a generating station of Pennsyl-
vania Power and Light Company at Sunbury, Pa., to undergo
field shakedown testing. The 15 cm diameter ducting sup-
plied with the unit was connected through a 15 x 10 cm
reducer to a 10 cm port in the breaching of No. 1-A boiler,
between the induced draft fans and the plant baghouse
installation. Gas withdrawn from the breaching at this
point contained 2300 - 6870 mg/m3 of dust and about 1200
ppm
A stepwise startup of the scrubber systems revealed no signi-
ficant deficiencies or difficulties in overall functioning
of systems and components. Within a matter of minutes, how-
ever, the pH of the liquid in the closed- loop curculating
system dropped to about 1.7 and SC>2 gas-off from the solids
filter made the process area of the trailer virtually unin-
habitable. Opening the rear door of the trailer afforded
little relief since an exhaust fan in the forward end of
the process area carried SO2 forward throughout the length
of the process area (refer to Figure 13) . Conditions in
the control room were tolerable, however, and since the
systems can be operated largely from this point, it was
possible to proceed with characterizing the scrubbers with
respect to flow and pressure drop.
In Figure 4 it is seen that the drain line from the venturi
cyclone does not contain a valve. During operation of the
35
-------
Figure 7. Sieve Tray Column
36
-------
30
25
a 20
o
§
Q
15
CO
W
w
£
10
10
m3/min
.118
0.09^
O-0.32 cm HOLES
A-0.48 cm HOLES
EJ-0.64 cm HOLES
50
100
L/G, m-^-sec/lO^m^-sec
Figure 8. Sieve Tray Characteristic Curves
200
37
-------
Figure 9. Venturi Scrubber
38
-------
Q
W
300
200
100
60
20
0.1^2 nr/seo
0.6
1.0
2.0
L/G, m^-
6.0
10
Figure 10. Characteristic Curves
Small Throat Venturi
39
-------
200
o
*
I
I
CO
s
L/G, n-
Figure 11. Characteristic Curves
Medium Throat Venturi
-------
100
50
§
1
10
0.283 aVsec
0
0.189
0.142
0.094
0.5
1.0
L/G,
5
10
Figure 12. Characteristic Curves
Large Throat Venturi
-------
Ate.
y j/Z-
t=^j
J
SOLIOS
FANS
o
TJ
Figure 13. Schematic Plan of Scrubber Unit
-------
sieve tray scrubber, considerable bypassing of gas through
the venturi and cyclone to the sump tank was observed. The
bypass vapor circuit in this case is: through the venturi
and cyclone to the sump tank, up the demister drain line.
This is a logical consequence of the fact that the demister
drain line, which is not submerged at the sump tank end,
taps in, at its upper end, at about the lowest pressure
point in the system. Further, with a copious gas flow up
the demister drain line, a downward flow of liquid would be
strongly inhibited, if not prevented.
A manual valve was installed in the cyclone drain line to
alleviate, in the field, the bypassing situation. However,
it was not possible in the field to correct the demister
drain line arrangement.
Within a week of operation, erratic, inconsistent, gas flow
readings were observed and traced to accumulation of dust
in the pressure taps in the flow nozzle (Figure 14). There
was no way in the field to remedy this condition except to
remove the nozzle section and clean out the dust accumula-
tion.
Within two weeks of performance testing operations, the
induction fans failed with severe damage to the fans. The
apparent cause was accumulation of liquid in the fans from
one or a combination of the following: condensation from
saturated scrubber exhaust, penetration of mist through the
mist eliminator, or failure of the mist eliminator to drain
to the sump tank. The situation was aggravated by the fact
that the liquid in the fans was extremely corrosive from
absorption of SC>2.
The scrubber unit was returned to NSWC, who repaired the
fans and attempted to analyze the cause of failure. They
concluded that:
Ball drive failures were caused by continuous water
carry over from the scrubber system. This carry
over in the gas stream increased the density of the
medium (gas and entrained water) being pumped by the
blower. An over-torque condition resulted, causing
ball drive slippage (normally designed to roll except
when short torque overloads occur). The increased
friction caused overheating and spalling in the ball
drive unit.
Impeller failure was caused by a combination of
erosion of the aluminum impeller by entrained par-
ticles in the high velocity gas stream, and high
43
-------
torque loading on the rotor caused by large quantities
of entrained water in the gas stream.
While these conclusions are valid as far as they go, they
are not comprehensive of the total situation. For example,
they make no mention of the highly corrosive environment to
which the fans were subjected. The main problem with the
fans is their inherent delicacy for such severe service.
It is virtually impossible to prevent either liquid or solids
from entering and accumulating in the fans, and in many in-
stances the wet gas will be extremely corrosive.
In an effort to minimize entrained particulate carry over
to the fans, NSWC installed a cartridge filter element be-
tween the mist eliminator and the fans. A vacuum bottle
and pump were furnished to remove liquid collected by the
element.
To mitigate the situation of S02 gas-off from the solids
filter, NSWC completely enclosed the filter in opaque plas-
tic film and installed a small fan to exhaust from beneath
this covering through the trailer wall to the atmosphere.
Simulated Field Testing at RTF
When the scrubber unit was returned to the RTF, it was set
up for extensive operational testing under simulated stack
gas conditions, i.e., both fly ash and SC>2 were injected
into the entering ambient air stream.
A significant point of interest during these tests was per-
formance of the solids filter. At Sunbury, the filter pass-
ed a considerable amount of fines, and the filter cloth was
observed to index frequently, presumably due to rapid blind-
ing of the cloth. However, due to the short, intermittent
operation at Sunbury, it was not possible to determine to
what extent fines would accumulate in the scrubbing liquid,
or what effect such condition would have. Neither was it
possible to establish whether the apparent rapid blinding
of the filter cloth was a transient or persistent effect.
Operation at RTF was also not long enough to settle the
question of fines accumulation, but performance of the fil-
ter in regard to cloth blinding was quite satisfactory.
The major difficulty with the solids filter lay in its being
totally wrapped in opaque plastic, which not only prevented
observing its performance, but also prevented access to the
44
-------
solids discharge hopper and other points of service.
Consequently, this arrangement was completely removed and
replaced with a plexiglass hood, which permits observation
and access to service points, and provides for collection
and discharge of gas-off from the filter liquid.
With the trailer exhaust fan arrangement as initially in-
stalled, air flow was from the back of the trailer forward.
This flow was so strong as to cause the small filter exhaust
fan to run backwards because of the draft entering through
it from outside. The direction of rotation of the exhaust
fan was reversed. This not only permitted the filter ex-
haust fan to function, but trailer ventilation was in the
more desirable direction of front to rear.
The solenoid valve in the sieve-tray scrubber drain line
became inoperative from deposition of fly ash in the pilot
flow chamber and, generally, in the working parts of the
valve. It was replaced by a manual valve with no inter-
ference in scrubber operation. It was anticipated the same
fate would befall the solenoid valve in the presaturator
drain, but it was decided to prove this in the field.
The flow patterns in the demister drain, sump tank, and in-
line gas filter were revealed to be indiscriminate and in-
adequate. The sump tank had no vent, per se, the only vapor
outlet being, as previously noted, up through the demister
drain line. This arrangement effectively obviated liquid
flow down the line to the sump tank and resulted in the in-
line filter carrying the liquid burden from the demister.
The vacuum drainage system provided for the in-line filter
was inadequate to cope with this load. As noted earlier,
the demister drain line terminus at the sump tank was not
immersed but was flush with the top of the tank while all
other liquid lines entered submerged.
These interrelated lines were rerouted as follows. First,
the demister drain line was teed into the presaturator drain
line, which has a submerged terminus in the sump. This pro-
vided liquid seal against gas bypassing through the pre-
saturator to the demister, since the total liquid head avail-
able for sealing is in excess of the system pressure. Second,
a vapor vent line was installed from the former demister
drain line tap, on the sump tank top, to a point downstream
of the in-line filter. Since this point represents the low-
est pressure point in the system, the sump tank is also at
low pressure, encouraging all liquid flow in this direction
while permitting separate vapor flow from the tank. Third,
the vacuum-pump/vacuum-bottle arrangement for draining the
in-line filter was replaced by a line from the filter
45
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element to the sump tank with submerged discharge. Since,
as noted, the sump tank is at the lowest pressure in the
system, there is adequate driving force to drain the in-line
filter to the sump tank. The revised system is shown sche-
matically in Figure 15 for comparison with Figure 4.
During testing at RTF, erratic gas flow readings were again
observed and, again, traced to dust accumulation in the flow
nozzle differential-pressure taps. A series of air nozzles
was installed around the circumference of the flow nozzle
to permit short, frequent air blasts to clear out the dust
accumulation. A small paint-spray compressor supplies the
air blast.
Field Testing at Plymouth
On completion of testing and modifications at RTF, the
scrubber unit was taken to Weyerhauser Corporation's pulp
mill at Plymouth, N. C., and connected to the exhaust
breaching of a lime recovery kiln. As expected, the sole-
noid valve in the presaturator drain line soon became in-
operable from solids pluggage and had to be replaced by a
manual ball-valve. Otherwise, at this writing, all systems
are performing as expected. There has not, however, been
sufficient operating time to reveal more obscure problems
anticipated such as the effect of fines accumulation in the
closed-loop scrubber-liquor system and pluggage of the Pall
ring section in the presaturator.
46
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Figure 14. Dust Accumulation
in Flow Nozzle
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tALL VALVE
X
UTTEHR-Y WLVE
Morem MIVCN
UTTCRFLY VALVE
THMOTTL* VALVE
SOLENOID VALVE
CHECK VALVE
PflOCEU IMSTItUHENTATION tTATION
Figure 15. Revised Flow
Schematic
-------
V. REFERENCES
Hall, R. Mobile Fabric Filter System - Design Report.
GCA/Technology Division. Contract No. 68-02-1075.
October 1974.
Hall, R. Mobile Fabric Filter System - Final Report.
GCA/Technology Division. Contract No. 68-02-1075.
May 1975.
Opferkuch, R. E. , S. P. Schliesser, and S. R. Turney.
Mobile Baghouse Unit - Technical/Operations Report.
Monsanto Research Corporation. Contract No. 68-02-1816
March 1975.
49
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VI. APPENDIX A
BAGHOUSE MECHANICAL AND
OPERATIONAL DIFFICULTIES
ENCOUNTERED IN THE FIELD
Problem
Apparent Cause
Remedial Action
Site
1. Condensation
-slipstream duct
-baghouse
-exhaust fan
(see Figure 16)
ui
o
a. Leakage (dilution) .at duct
joints (Morris couplings)
b. Leakage at baghouse section
flanges, glass windows, bag-
shaker suspension rods, rotary
valve in dust hopper discharge
c. Conductive and radiant heat loss:
duct, baghouse, exhaust fan
a. Plastic rubber sealant (Silastic)
applied at duct joints
b. All flanged joints sealed with
plastic rubber, in the field.
Subsequently, heavy asbestos
gaskets provided for flanged
joints. Could not cope with
shaker rods in field. Subse-
quently provided rubber 0-ring
seals. Removed rotary valve and
sealed outlet with blind flange.
c. 3-1/2" fiberglass insulation
applied on top of magnesia insul-
ation. Baghouse exhaust duct and
blower fiberglass insulated.
Plyr.outh
2. Flow controller
failure
Ruptured bellows
Manual control with measurement
by pitot tube. Replacement parts
ordered for repair
Plymouth
3. Dust pluggage in
discharge hopper
Dust bridging above rotary dis-
charge valve. Probable causes:
-moist solids
-air leakage through rotary valve
-inadequate hopper ancle
Remove valve, seal with blind
flange, manual cleanout. Sub-
sequently added hopper vibrators
Plymouth
-------
4. Restricted flow rate
through baghouse
Induction fan drive
inadequate HP
Changing fan/motor pulley combina-
tion to achieve higher fan speed
overloaded motor, circuit breaker.
Subsequently replaced with larger
drive
Plymouth
5. High temperature
controller failure
Both high and low temperature
controllers wired wrong. High
temperature controller burned
out '
Controllers rewired but only low
temperature controller operative
6\ Lack of accessability
to control console
circuitry
Poor design
None with present product. Con-
sole must be virtually disassembled
to troubleshoot and repair
7. Induction fan out of
balance
Solids deposits on, corrosion
of wheel
Removed wheel, sandblasted, re-
balanced
Sunbury
8. Failure of bag differ-
ential pressure indi-
cator recorder
Unknown
Use Magnehelic gauges to
indicate
9. Dust pluggage in dis-
charge hopper
Solids bridging above rotary
discharge valve. Vibrators
ineffective
Remove valve, seal with blind
flange, manual cleanout
10. SC>2-laden gas contam-
inating work area
Gas leakage around flow control
damper (positive pressure point
in system)
Personnel wear respirators. Could
not seal as shaft must be free to
rotate. Subsequently moved damper
to negative pressure point in
system
11. Unable to install
felt bags
Bag hangers could not accept
thickness of felt bag material
Bags notched to adapt to hangers.
Subsequently, new hangers designed,
installed
12. Gate valves sticking
Solids deposits on moving gate
parts and seats prevented full
closure or resistance to move-
ment from a s exposition
Rapping valve assembly with hanmer,
disassembly and cleaning
-------
13. Malfunction of flow
control danper
Loose linkages between controller
and damper
Linkages adjusted
Plymouth
Reversa flow fan
failure
Plastic wheels deformed from
hii^h temperature
None. Metal wheel replace-
ments planned
15. Dust pluggage in
discharge hopper
Dust bridging above rotary
discharge.valve
Hopper kept at elevated temper-
ature by heat tapes permitted
solids flow
16. Gate valves inoper-
able
Solids deposits on moving gate
parts and seats froze position
Disassemble and clean. Require
redesign
to
-------
Figure 16. Mud Deposit in
Induction Fan Inlet
53
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VI. APPENDIX B
Graphs of Percent Penetration
by
Particle Size
54
-------
o
M
EH
W
8
K
Percent Penetration by Particle Size
EFFECT OF AIR/CLOTH RATIO
Shake Mode, Nomex Woven Bag
10
7 a » 10
SIZE, MICRONS
55
-------
Percent Penetration by Particle Size
EFFECT OF AIR/CLOTH RATIO
Shake Mode, Nomex Felt Bag
55
O
3
o
01
K
.2
7 8 » 10
10
SIZE, MICRONS
-------
Percent Penetration by Particle Size
EFFECT OF AIR/CLOTH RATIO
Pulse Mode, Nome* Felt Bag
53
o
a
8
8
( 7 » 9 10
SIZE, MICRONS
57
-------
Percent Penetration by Particle Size
EFFECT OF PULSE INTERVAL
Pulse Mode, Nomex Felt Bag
10
iov
SIZE, MICRONS
58
-------
Percent Penetration by Particle Size
EFFECT OF AIR/CLOTH RATIO
AND PULSE INTERVAL
SIZE, MICRONS
59
-------
Percent Penetration by Particle Size
EFFECT OP AIR/CLOTH RATIO
Reverse Mode, Glass Bag
10-
o
M
H
W
P«
I
10'
4 6 678910
6 ( 7 8 10
10
SIZE, MICRONS
60
-------
Percent Penetration by Particle Size
EFFECT OF FILTRATION TIME
Reverse Mode, Glass Bag
10'
r^
a
B
a
B
O
10'
7 t t 10
SIZE, MICRONS
61
-------
Percent Penetration by Particle Size
EFFECT OF AIR/CLOTH RATIO
Reverse Mode, Nomez Felt Bag
S3
o
I. -
S
B
10
6 * T t t 10
SIZE, MICRONS
62
-------
Percent Penetration by Particle Size
EFFECT OF FILTRATION TIME
Reverse Mode, Nomex Felt Bag
10'
o
M
H
I
W
8
e
10'
2 3 4 6678910
2 3 4 56789 10
20 8 4 ft * T 9 1
10'
10
SIZE, MICRONS
63
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TECHNICAL REPORT DATA
(Phase read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-76-042
2.
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
Particulate Control Mobile Test Units: First Year's
Operation
5. REPORT DATE
February 1976
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
Robert E. Opferkuch
9. PERFORMING OR8ANIZATION NAME AND ADDRESS
Monsanto Research Corporation
1515 Nicholas Road
Dayton, Ohio 45407
10. PROGRAM ELEMENT NO.
1AB012; ROAP 21ADM-034
11. CONTRACT/GRANT NO.
68-02-1816
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Initial year
14. SPONSORING AGENCY CODE
EPA-ORD
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The report summarizes the first year of operation of EPA-owned mobile
test units that are being used in the field to study the applicability of different con-
trol methods to the control of fine particulate emitted from a wide variety of
sources. Two mobile units are described: a fabric filter (baghouse) and a wet
scrubber. The latter includes two types: venturi and sieve tray. Results from the
baghouse tests on a coal-fired power plant indicate suitability of a baghouse, with
woven glass bags, for control of dust from this type of source. Results from tests
on a pulp mill lime recovery kiln show high dust removal efficiency; however, the
associated high moisture content of the gases portends operating problems sufficient
to indicate that a baghouse would be unsuitable for control of dust from this source.
Operation of the mobile scrubber unit during the year was confined to startup tes-
ting and correction of mechanical and operating difficulties.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Air Pollution
Dust
Dust Collectors
Mobile Equipment
Test Equipment
Field Tests
Woven Fabrics
Glass Fibers
Filters
Scrubbers
Electric Utilities
Pulp Mills
Kilns
Coal
Air Pollution Control
Stationary Sources
Fine Particulate
Baghouses
Wet Scrubbers
Venturi
Sieve Tray
13B
11G
13A
15E
14B
HE
11B
07A
21D
B. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
70
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
64
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