EPA-600/7-78-056
Office of Research and Development Laboratory __ . HOTO
Research Triangle Park, North Carolina 27711 MaTCR 1978
TESTS OF FABRIC
FILTRATION MATERIALS
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EPA-600/7-78-056
March 1978
TESTS OF FABRIC
FILTRATION MATERIALS
by
Jan R. Koscianowski, Lidia Koscianowska,
and Maria Szablewicz
Institute of Industry of Cement Building Materials
(IPWMB)
45-641 Opole
Oswiecimska Str. 21 POLAND
Public Law 480 (Project P-5-533-4)
ROAP 21ADJ-094
Program Element No. EHE624
EPA Project Officer: James H. Turner
Industrial Environmental Research Laboratory
Office of Energy, Minerals and Industry
Research Triangle Park, N.C. 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, D.C. 20460
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ABSTRACT
This report describes laboratory and pilot scale testing of filter
fabrics. Tests were made on flat specimens and on bags. Fifteen
styles of fabrics made from cotton, polyester, aramid or glass
were tested using cement, coal or talc dusts. Collection efficiencies
and pressure drop data are presented for inlet dust concentrations
3 32
of 10 - 11 g/m , filtration velocities of 60 and 80 m /m -hr,
temperatures of 20 to 30°C and relative humidities of 55 to 60 percent.
Conclusions reached were: 1) fabrics which performed well on bench scale
apparatus also performed well on large scale apparatus, 2) free area
calculations for characterizing fabrics are useful for staple fiber
fabrics, but not for continuous filament fabrics, 3) smooth fiber fabrics
with low coefficients of friction may have poor collection efficiency at
high filtration velocities, 4) cleaning properties of fabrics depend
on the fabric composition and structure, and on dust properties, but
not on filtration velocity.
Collateral tests are described.
ii
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TABLE OF CONTENTS
SECTION PAGE
1.0 INTRODUCTION 1
1.1 Methods of Filter Fabric Testing 3
1.2 Interpretation of Results of Experiments 5
2.0 RESEARCH OBJECTIVES 8
2.1 General Program 8
2.2 Detailed Program for the First Phase 9
2 .3 Fabric and Dust Selection 10
3.0 LABORATORY TESTS OF FILTRATION 22
3.1 Equipment and Procedures 22
3.2 Results and Discussion 25
3.2.1 Air Flow Through Clean Fabrics 25
3.2.2 Laboratory Testing of Filtration Fabrics.. 32
3.3 Conclusions 50
4.0 LARGE-SCALE TESTING 51
4.1 Equipment and Procedures 51
4.2 Results and Discussion 59
4.3 Conclusions 70
5.0 STUDY OF REGENERATION PROPERTIES OF FABRICS 71
5.1 Introduction 71
5.2 Results and Discussion 76
5.3 Conclusions 81
6.0 CONCLUSIONS 83
7 .0 RECOMMENDATIONS 84
iii
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TABLE OF CONTENTS (Continued)
SECTION PAGE
APPENDIX A 85
APPENDIX B 179
APPENDIX C 196
APPENDIX D 198
APPENDIX E 200
IV
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LIST OF FIGURES
FIGURE PAGE
1 Comparison of Efficiency in Laboratory and Large-Scale.. 7
2 Illustration of Laboratory Stand 22
3 Diagram of the Laboratory Test Stand 23
4 Hydraulic Characteristic of Polyester Fabrics 27
5 Hydraulic Characteristic of Glass, Cotton and Nylon
Fabrics 28
6 Hydraulic Characteristic of Nomex Fabrics 28
7 Pressure Drop vs. FA for Clean Air Flow 40
8 Comparison of Cross-Sections of Threads with Continuous
Filament and Staple Fibers 41
9 Effect of "Free Fibers" on Fabric Structure 42
10 Surface of Dust Cake on Fabric 862B 43
11 Surface of Dust Cake on Fabric Q53-875 46
12 Surface of Dust Cake on Fabric Q53-870 47
13 Surface of Dust Cake on Fabric Q53-878 48
14 Illustration of the Large-Scale Stand 51
15 Diagram of the Large-Scale Test Stand 53
16 Diagram of Regeneration Cycles 55
17 Construction of Bags 56
18 Efficiency vs. Gas Loading of Filtration Area for
Cotton Fabrics 64
19 Efficiency vs. Gas Loading of Filtration Area for
Polyester Fabrics 65
20 Efficiency vs. Gas Loading of Filtration Area for
Nomex Fabrics 66
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LIST OF FIGURES (Continued)
FIGURE PAGE
21 Efficiency vs. Gas Loading of Filtration Area for
Glass Fabrics 67
22 Theoretical Run of Filtration and Regeneration Process.. 73
23 Practical Run of Filtration and Regeneration Process.... 74
24 Characteristic of Pressure Drop Values in Dust
Filtration Process 75
A-l Particle Size Distribution of Cement Tested Dust 86
A-2 Particle Size Distribution of Coal Tested Dust 87
A-3 Particle Size Distribution of Talc Tested Dust 88
A-4 Surface of Clean Fabric Style 960 89
A-5 Surface of Clean Fabric Style 862B 90
A-6 Surface of Clean Fabric Style C866B 91
A-7 Surface of Clean Fabric Style C868B 92
A-8 Surface of Clean Fabric Style 865B 93
A-9 Surface of Clean Fabric Style C890B 94
A-10 Surface of Clean Fabric Style C892B 95
A-ll Surface of Clean Fabric Style 852 96
A-12 Surface of Clean Fabric Style 853 97
A-13 Surface of Clean Fabric Style 190 98
A-14 Surface of Clean Fabric Style 850 99
A-15 Surface of Clean Fabric Style 802B 100
A-16 Surface of Clean Fabric Style Q53-875 101
A-17 Surface of Clean Fabric Style Q53-870 102
A-18 Surface of Clean Fabric Style Q53-878 103
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LIST OF FIGURES (Continued)
FIGURE PAGE
A-19 Pressure Difference vs. Filtration Time for Fabric
Style 960 104
A-20 Pressure Difference vs. Filtration Time for Fabric
Style 862B 105
A-21 Pressure Difference vs. Filtration Time for Fabric
Style C866B 106
A-22 Pressure Difference vs. Filtration Time for Fabric
Style C868B 107
A-23 Pressure Difference vs. Filtration Time for Fabric
Style 865B 108
A-24 Pressure Difference vs. Filtration Time for Fabric
Style C890B 109
A-25 Pressure Difference vs. Filtration Time for Fabric
Style C892B 110
A-26 Pressure Difference vs. Filtration Time for Fabric
Style 852 Ill
A-27 Pressure Difference vs. Filtration Time for Fabric
Style 853 112
A-28 Pressure Difference vs. Filtration Time for Fabric
Style 190 113
A-29 Pressure Difference vs. Filtration Time for Fabric
Style 850 114
A-30 Pressure Difference vs. Filtration Time for Fabric
Style 802B 115
A-31 Pressure Difference vs. Filtration Time for Fabric
Style Q53-875 116
A-32 Pressure Difference vs. Filtration Time for Fabric
Style Q53-870 117
A-33 Pressure Difference vs. Filtration Time for Fabric
Style Q53-878 118
A-34 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 960 (talc dust, q = 60m3/m2/hr) 119
&
vii
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LIST OF FIGURES (Continued)
FIGURE PAGE
A-35 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 960 (talc dust, q = 60m3/m2/hr) 120
&
A-36 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric C866B (talc dust, q = 60m3/m2/hr) 121
&
A-37 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric C868B (talc dust, q = 60m3/mx/hr) 122
O
A-38 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 865B (talc dust, q = 60m3/m2/hr) 123
O
A-39 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric C890B (talc dust, q = 60m3/m2/hr) . .. . 124
&
A-40 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric C892B (talc dust, q = 60m3/m2/hr) 125
O
A-41 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 852 (talc dust, q = 60m3/m2/hr) 126
&
A-42 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 853 (talc dust, q = 60m3/m2/hr) 127
O
A-43 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 190 (talc dust, q = 60m3/m2/hr) 128
6
A-44 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 850 (talc dust, q = 60m3/m2/hr) 129
&
A-45 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 802B (talc dust, q = 60m3/m2/hr) 130
O
A-46 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 053-875 (talc dust, q = 60m3/m2/hr).. 131
&
A-47 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric Q53-870 (talc dust, q = 60m3/m2/hr),. 132
O
A-48 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric Q53-878 (talc dust, q = 60m3/m2/hr).. 133
&
A-49 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 960 (talc dust, q = 80m3/m2/hr) 134
&
A-50 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 862B (talc dust, q = 80m3/m2/hr) 135
O
viii
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LIST OF FIGURES (Continued)
FIGURE PAGE
A-51 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric C866B (talc dust, q = 80m3/m2/hr) 136
o
A-52 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric C868B (talc dust, q = 80m3/m2/hr) 137
o
A-53 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 865B (talc dust, q = 80m3/mz/hr).... 138
&
A-54 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric C890B (talc dust, q = 80m3/mx/hr) 139
&
A-55 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric C892B (talc dust, q = 80m3/m2/hr) 140
O
A-56 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 852 (talc dust, q = 80m3/m2/hr) 141
o
A-57 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 853 (talc dust, q = 80m3/m2/hr) 142
&
A-58 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 190 (talc dust, q = 80m3/m2/hr) 143
O
A-59 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 850 (talc dust, q = 80m3/m2/hr) 144
O
A-60 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 802B (talc dust, q = 80m3/m2/hr) 145
O
A-61 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric Q53-875 (talc dust, q = 80m3/m2/hr).. 146
6
A-62 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric Q53-870 (talc dust, q = 80m3/m2/hr).. 147
O
A-63 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric Q53-878 (talc dust, q = 80m3/m2/hr).. 148
5
A-64 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 960 (coal dust, q = 60m3/m2/hr) 149
O
A-65 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 862B (coal dust, q = 60m3/m2/hr) 150
&
A-66 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric C866B (coal dust, q = 60m3/m2/hr) 151
o
ix
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LIST OF FIGURES (Continued)
FIGURE PAGE
A-67 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric C868B (coal dust, q = 60m3/m2/hr) 152
o
A-68 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 865B (coal dust, q = 60m3/m2/hr) 153
&
A-69 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric C890B (coal dust, q = 60m3/m2/hr) 154
O
A-70 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric C892B (coal dust, q = 60m3/m2/hr) . .. . 155
&
A-71 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 852 (coal dust, q = 60m3/m2/hr) 156
5
A-72 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 853 (coal dust, q = 60m3/m2/hr) 157
O
A-73 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 190 (coal dust, q = 60m3/m2/hr) 158
O
A-74 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 850 (coal dust, q = 60m3/m2/hr) 159
5
A-75 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 802B (coal dust, q = 60m3/m2/hr) 160
O
A-76 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric Q53-875 (coal dust, q = 60m3/m2/hr). . 161
O
A-77 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric Q53-870 (coal dust, q = 60m3/m2/hr).. 162
&
A-78 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric Q53-878 (coal dust, q = 60m3/m2/hr).. 163
O
A-79 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 960 (coal dust, q = 80m3/mx/hr) 164
O
A-80 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 862B (coal dust, q = 80m3/m2/hr) 165
O
A-81 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric C866B (coal dust, q = 80m3/m2/hr).... 166
&
A-82 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric C868B (coal dust, q = 80m3/mz/hr) 167
O
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LIST OF FIGURES (Continued)
FIGURE PAGE
A-83 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 865B (coal dust9 q = 80m3/m2/hr) 168
o
A-84 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric C890B (coal dust, q = 80m3/m2/hr) 169
O
A-85 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric C892B (coal dust, q = 80m3/m2/hr) 170
O
A-86 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 852 (coal dust, q = 80m3/m2/hr) 171
O
A-87 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 853 (coal dust, q = 80m3/m2/hr) 172
o
A-88 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 190 (coal dust, q = 80m3/m2/hr) 173
&
A-89 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 850 (coal dust, q = 80m3/m2/hr) 174
O
A-90 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric 802B (coal dust, q = 80m3/m2/hr) 175
&
A-91 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric Q53-875 (coal dust, q = 80m3/m2/hr).. 176
O
A-92 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric Q53-870 (coal dust, q = 80m3/m2/hr).. 177
o
A-93 Pressure Difference vs. Filtration Time for Large-Scale
Testing of Fabric Q53-878 (coal dust, q = 80m3/m2/hr).. 178
O
XI
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LIST OF TABLES
TABLE PAGE
1 Fabric Parameters 12
2 Physical Properties of Test Dusts 17
3 Particle Size Distribution of Cement Dust 18
4 Particle Size Distribution of Coal Dust 19
5 Particle Size Distribution of Talc Dust 20
6 Chemical Properties of Test Dusts 21
7 Values of Characteristic Factor "C" 29
8 Free Area for Investigated Fabrics 31
9 Laboratory Efficiency of Tested Filtration Fabrics 33
10 Filtration Resistance at Laboratory Tests 36
11 Number of Ducts/Canals Observed in Laboratory Testing... 45
12 Large-Scale Efficiency of Tested Filtration Fabrics 61
13 Comparison of Qualitative Parameters of Fabrics 69
14 Susceptibility for Regeneration of Fabrics Tested with
Talc Dust (q = 60m3/m2/hr) 77
o
15 Susceptibility for Regeneration of Fabrics Tested with
Talc Dust (q = 80m3/m2/hr) 78
O
16 Susceptibility for Regeneration of Fabrics Tested with
3 2
Coal Dust (q = 60m /m /hr) 79
O
17 Susceptibility for Regeneration of Fabrics Tested with
3 2
Coal Dust (q = 80m /m /hr) 80
O
B-l Pressure Drop vs. Gas Loading of Filtration Area for
Pure Fabrics 180
Xll
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LIST OF TABLES (Continued)
TABLE PAGE
B-2 Characteristic Pressure Drop for Reverse Air Flow
3 2
Regeneration (talc, q = 60m /m /hr) 188
o
B-3 Characteristic Pressure Drop for Mechanical
3 2
Regeneration (talc, q = 60m /m /hr) 189
&
B-4 Characteristic Pressure Drop for Reverse Air Flow
3 2
Regeneration (talc, q = 80m /m /hr) 190
O
B-5 Characteristic Pressure Drop for Mechanical
3 2
Regeneration (talc, q = 80m /m /hr) 191
O
B-6 Characteristic Pressure Drop for Reverse Air Flow
3 2
Regeneration (coal, q = q = 60m /m /hr) 192
O ft
B-7 Characteristic Pressure Drop for Mechanical
3 2
Regeneration (coal, q = 60m /m /hr) . 193
O
B-8 Characteristic Pressure Drop for Reverse Air Flow
3 2
Regeneration (coal, q = 80m /m /hr) 194
&
B-9 Characteristic Pressure Drop for Mechanical
3 2
Regeneration (coal, q = 80m /m /hr) 195
O
xiii
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ACKNOWLEDGMENTS
As authors, we thank each employee of the United States Environmental
Protection Agency who participated in this endeavor for their contribution
and help. Special thanks for help and support throughout the program
are extended to our Project Officer, Dr. James H. Turner.
xiv
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1.0 INTRODUCTION
Filtration has been defined as a process for removal of solid
particles from an aerosol by a porous medium. Widest industrial
application has been found for textile media, which can be subdivided
into two groups: non-woven (fibers, mattes, felts) and woven (filter
fabrics). These two groups have differences in surface and spatial
structure which, depending upon filtration and process parameters,
determine the choice between the two.
There are many publications in engineering and scientific journals
about textile filtration media, in which different authors chose different
testing conditions to confirm empirical dependences. The conclusions
from these experiments have not proven to be very useful under alternate
conditions, particularly with different aerosols and filtration media.
Classical filtration theory was born in the First and Second World
Wars with efforts to establish a theoretical base for removal of toxic
substances and solid pollutants from the air. The special requirements
of the nuclear power industry and the space program have influenced the
development of the theory, and it is still being refined. Increasing
pressures on the legislatures concerning dust emission into the air
during the last twenty years has stressed the need for theoretical studies
of the dust collectors used for industrial filtration.
Although the description of the filtration process on a macroscopic
level for given aerosol and filter parameters has been relatively easy, its
generalization to the microscopic level in terms of particulate properties
and structural parameters is still the subject of investigation. Many
-------
authors have tried to base the description of filtration processes
on classical filtration theory and have derived general mathematical
relations. But these seem inadequate in light of the differences
between atmospheric filtration, for which the theory was derived, and
industrial filtration; for example, the possibility of filter structure
regeneration in a dust collector.
From previously published studies, three main types of filtration
processes can be delineated:
1) High efficiency filtration with initial particle concentrations
3 3
below 1 mg/m (or 0.5 mg/m ),
3
2) Air filtration at initial concentrations between 1 mg/m and
3
50 mg/m , and
3
3) Dust filtration at initial concentrations above 50 mg/m .
Each of these processes requires special conditions to insure that
separate filtration mechanisms predominate. The initial concentration,
according to which the three groups are divided, is the decisive factor
for selecting parameters for the filtration process and determining its
efficiency. It also determines the focus of the investigation with
regard to particle interactions and the effects of filter structure.
Industrial dust collectors fall into Group 3 because the initial
concentrations are far in excess of 50 mg/m . The major operating
characteristic of this group is the formation of a dust cake on the
filter structure, followed by a cyclic regeneration. At present, there
is no mathematical description of the dust filtration process which
could make possible prediction of filter characteristics in industrial
-------
applications, optimization of filter media structures and filtration
parameters, and projection of the optimized filtration structure for
defined filtration conditions.
In this situation, there is wide application of empirical methods
in selection of the filter medium in filtration conditions. A selection
of filter media is usually done prior to testing, with consideration
of aerosol temperature, aerosol humidity, aerosol corrodibility, and
method of filter regeneration. As a result of the selection, we obtain
a group of filter media which are satisfactory from the point of view
of thermal, chemical, and mechanical resistance.
Economic factors also have weight in the selection process, using
qualitative filter medium parameters (efficiency, flow resistance), which
may be obtained from permeability data, results of brief tests, or prior
experience. Finally, pilot tests of certain filter media of differing
structures should be run to select the best medium for specific applica-
tions, with the type and degree of testing dependent upon the importance
of the problem.
Apart from such applications testing of filter materials, testing
methods are also the scientific foundation for the investigation of the
peculiarities of dust filtration. Of course, they are different in scope,
and the criteria of choice are based upon the scientific premises connected
with the problem.
1.1 Methods of Filter Fabric Testing
Tests of textile media are conducted in four levels of experiments:
laboratory scale, large scale, pilot scale and industrial scale.
Laboratory testing is conducted with samples of selected filtration
2
fabrics with a surface area of 100-300 cm . Dusty air can flow through
-------
the fabric in an upward or downward direction, and the dust collection
efficiency is evaluated by weighing. The pressure drop as a function
of time is also recorded. Laboratory testing measures Type I dust
filtration, the initial filtering action of a virgin filtration medium.
The dust used for testing can be separated or unseparated, according
to the requirements of the testing program. Laboratory testing allows
easy variation of the experimental conditions to identify and define
their effects on filtration.
Large scale testing is conducted on full-size filtration equipment,
usually one to four bags installed in a special casing. It simulates
the industrial experimental conditions with respect to regeneration and
the thermodynamic parameters of the dispersion medium. The generation
of the aerosol is performed by injecting dust into the gas or air stream
with the help of a dust feeder. Large scale testing operates with Type
III dust filtration, where multiple loading and regeneration of the
fully filled fabric occurs. The degree of filling depends upon the
strength of the regeneration system. Industrial dusts are used in large
scale testing, just as well-characterized dusts are used in laboratory
scale testing. The test stands allow for performing the same kinds of
experiments as in laboratory testing, but the time involved is much
longer because a larger area must be filled.
Pilot Scale testing is conducted on miniaturized fabric filters which
collect some of the gases from the pilot system. These tests are capable
of giving very precise information on those aspects of filter media
relating to the aerosols. They are primarily empirical tests, facilitating
-------
the choice of filtration and regeneration times for the filter material.
Such testing also helps to estimate the bag life. Because of the
variability of the initial aerosol parameters, the results of pilot
testing are not significant for theoretical research, but can be used
to verify the tendencies of the process.
Industrial testing includes the whole filter device or dust control
system. It is conducted only in special cases or for very important
technologies because of very high costs and the relatively small amount
.of theoretical information obtained. Industrial scale tests do provide
the best actual confirmation of the filter selection process and the
performance of the filters.
1.2 Interpretation of Results of Experiments
The fact that there is no sound theoretical basis for interpreting
the dust filtration process means that interpretation is limited to the
specific conditions of the experiments. Interpretation is based on a
comparative analysis of qualitative fabric filtration performance for
special aerosols and types of dust. The performance factors to be com-
pared are the average dust removal efficiency and the time variation
dust-fabric resistance of the system for specific initial concentrations.
The regeneration properties of filter fabrics are also estimated
by comparison of values of the coefficient for regeneration susceptibility,
a coefficient which is directly connected with the structure of the filter
medium surface and fiber and dust properties. It can be defined in terms
of certain static pressure gradients.
A comparative analysis is conducted for each particular scale of
experiment. For instance, laboratory scale experiments measure different
-------
types of filtration from large scale experiments. The degree of evaluation
depends on the number of parameters used to characterize the process. The
comparative analysis can be conducted on a few chosen parameters or, in
a larger experimental program, on the functional form of the parameters.
The results obtained in laboratory scale testing usually give
lower values for dust removal efficiency and filtration resistance than
those obtained in large-scale tests. This is illustrated in Figure 1.
At present, it is very difficult to define the character of the correlation
between Type I and Type III dust filtration. This problem is still the
subject of investigation, and although laboratory scale testing does not
absolutely determine the qualitative parameters encountered on the
industrial scale, it still is a very important element of investigations.
According to our experience, filtration fabrics which had unsatisfactory
values for the parameters in laboratory tests were also regarded as fabrics
of low effectiveness in industrial conditions. It is important to note
that at present laboratory tests are necessary for development of new
fabric configurations and for evaluation of filtration mechanisms on dust
removal efficiency. It is possible that in the future the theoretical
foundation of dust filtration processes will allow the use of laboratory
tests for qualitative testing of manufactured textile media, substituting
efficiency and filtration resistance for the currently used permeability
magnitude.
-------
POLYESTER FABRIC
LARGE-SCALE
LABORATORY 3CALL
99,82
80 100 120 MO 160
GA3 LOADING OF FlLTKATIOfl AREA, IK
Figure 1 . Comparison of iix'ficiency in Laboratory
and Large-ocale.
-------
2.0 RESEARCH OBJECTIVES
The basic objectives of this research program, supported by the
EPA and conducted by the Institute of Cement Building Materials in
Opole, were: determination of the dust removal efficiency of fabrics
manufactured in the USA (supplied by EPA); determination of the flow
characteristics of fabrics, both clean and during filtration; compila-
tion and comparative analysis of the results in order to determine
the qualitative parameters of the tested fabrics; and evaluation of
the regeneration properties of the fabrics. The total program included
laboratory testing, large-scale testing, and auxiliary studies.
2.1 General Program
Laboratory testing was performed on fifteen kinds of filtratir-r
fabrics and four types of dust, under the following conditions:
1) Dust concentration at the inlet of the test chamber was
10-11 g/m3.
2
2) Dust loading on the filtration areas was 400 g/m with
AP < 250 mm water.
o o
3) Gas loading on the filtration areas was 60 and 80 m /m -hr.
4) The relative humidity of the dispersion medium (not adjustable)
was 55 to 60 percent.
5) The temperature of the dispersion medium was 20 to 30°C.
6) The dispersion medium was atmospheric air at atmospheric
pressure.
-------
Large-s._ale tests "ere performed using filtration bags with operating
lengths of 3300 mm, with the same dusts used in the laboratory testing.
All other te?f conditions were identical with those in the laboratorv
scale testing except for the relative humidity, which was 65 to 72
percent.
According to the results obtained in the laboratory testing and
large-scale tests, a comparative analysis will be conducted for
the purpose of determining the qualitative properties of the fabrics
for filtration of aerosols containing four types of dust. The results
obtained will be used for further investigations of the mathematical
model for the dust filtration process (Project P-5-533-3).
2.2 Detailed Program for the First Phase
The tasks for the laboratory tests were the following:
1) Preparation of separated cement, coal, and talc dusts,
using the ALPINE separator;
2) Determination of the physico-chemical properties of
separated and non-senarated dusts;
3) Testing of the filtration fabrics (15 kinds) received from
the USA, using cement, coal, and talc dusts; and
4) Compilation and preliminary analysis of these results.
The tasks for the large-scale testing were similar:
1) Separation of the testing dusts, cement and talc, by a
subcontractor;
2) Determination of physico-chemical properties of separated
and unseparated dusts;
3) Testing of fifteen kinds of filtration fabrics received from
the USA, using cement and coal dusts: and
9
-------
4) Compilation and preliminary analysis of the results.
The auxiliary studies consisted of:
1) Testing the flow properties of the filtration fabrics
during clean air flow;
2) Determination of the filtration fabric parameters according
to Polish standards;
3) Special testing of the fabrics with regard to structural
parameters;
4) Determination of the regeneration properties of the fabrics;
and
5) Preliminary analyses of these results.
2.3 Fabric and Dust Selection
Fifteen types of filtration fabrics were selected for use in the
majority of tests under this project, No. 5-533-4. These fabrics were
supplied by EPA and were manufactured in the USA from the following
raw materials:
Cotton (stable fiber): Globe-Albany Style 960;
TJ
Dacron polyester (staple fiber): Styles 862B, C866B, and C868B;
T>
Dacron polyester (continuous filament): Style 865B (staple fill),
Styles C890B and C892B;
TJ
Nomex aromatic nylon (staple filter): Styles 852, 853, and 190;
15
Nomex aromatic (continuous filament) : Style 850;
Nylon polyamide (staple fiber) : Style 820B;
Glass (staple fiber) : Style Q53-875
and Glass (continuous filament): Styles Q53-870 and Q53-878 (texturized
fill).
10
-------
The technical characteristics of these fibers are shown in Table 1.
The test dusts used were cement, coal, talc, and fly ash. These
industrial dusts were taken from appropriate points in the production
processing line in order to preserve their physico-chemical properties.
Separated dusts were used according to the contractors' stipulations,
and so the laboratory dusts were processed by the ALPINE separator, and
the dusts used in the large-scale tests were separated by subcontractors.
In accordance with suggestions from Dr. James H. Turner, EPA Project
Officer, testing was performed only with dust samples containing no more
than 10 percent by weight of particles with diameter greater than 20
micrometers. The subcontractor declined to separate coal dust for the
large-scale testing because of the explosive properties of finely divided
coal, and so the Project Officer agreed to conducting laboratory tests
with separated and unseparated coal dust but large-scale tests only on
unseparated coal dust. The physical and chemical properties of the test
dusts are shown in Tables 2 through 6 and Figures A-l through A-3.
11
-------
Table 1. FABRIC PARAMETERS
PARAMETER
Fabric Style No.
Fabric Weight
Thread count in 10 cm:
warp
fill
Thickness
2
(pressure = 20 g/cm )
Tensile strength: warp
fill
Elongation during
tension: warp
fill
Permeability
Weave
UNIT
g/m
mm
kg/5 cm width
kg/5 cm width
%
%
3 2
dm /m /second
at 10 mm H20
VALUE
862B
330
138
110
0.87
162
125
35
42
382
1
1
C866B
379
164
138
0.92
212
162
34
44
240
2
2 "
C868B
438
164
158
0.96
210
221
34
42
163
2
2 "
-------
Table 1 (continued)
Fabric Style No.
Fabric weight
Thread count in 10 cm:
warp
fill
Thickness
2
(pressure = 20 g/cm )
Tensile strength:
warp
fill
Elongation during
tension: warp
fill
Permeability
Weave
g/m
mm
kg/5 cm width
kg/5 cm width
%
%
3 2
dm /m /second
at 10 mm H20
865B
337
302
178
0.63
330
135
41
37
166
3
1
C890B 1 C892B
'
168
292
262
0.24
170
136
20
34
107
3
1 "
151
254
232
0.24
162
122
29
33
70
3
1 "
-------
Table 1 (continued)
Fabric Style No.
Fabric Weight
Thread count in 10 cm:
warp
fill
Thickness
2
(pressure = 20 g/cm )
Tensile strength:
warp
fill
Elongation during
tension: warp
fill
Permeability
Weave
g/m
TTTTTT
kg/ 5 cm width
kg/5 cm width
%
%
3 2
dm /m /second
at 10 mm H20
852
292
122
100
0.92
148
120
30
23
457
1
1
853
350
154
144
1.08
175
148
28
28
187
2
2 "
190
510
1.79
67.4
108
19
56
97
-------
Table 1 (continued)
Fabric Style No.
Fabric Weight
Thread count in 10 cm:
warp
fill
Thickness
2
(pressure = 20 g/cm )
Tensile strength:
warp
fill
Elongation during
tension warp
fill
Permeability
Weave
g/m
mm
kg/ 5 cm width
kg/ 5 cm width
%
%
3 3
dm /m /second
at 10 mm HO
960
337
384
238
0.74
99
103
15
14
45
4
1
850
155
380
288
0.24
188
151
40
35
148
3 7
I Z
802B
401
140
136
1.08
17U
179
41
44
140
2 „
2 Z
-------
Table 1 (continued)
Fabric Style No.
Fabric Weight
Thread count in 10 cm:
warp
fill
Thickness
2
(pressure = 20 g/cm )
Tensile strength:
warp
fill
Elongation during
tension: warp
fill
Permeability
Weave
g/m
mm
kg/5 cm width
kg/5 cm width
%
%
3 2
dm /m /second
at 10 mm H20
Q53-875
281
210
204
0.31
176
160
3.9
4.1
226
1
3 "
Q53-870
282
210
204
0.30
188
196
3.5
4.1
58
3 x
1 X
Q53-878
451
176
96
0.56
475
248
6
6
219
3
1 °
-------
Table 2. PHYSICAL PROPERTIES OF TEST DUST
PARAMETER
Angle of repose of dust
(on glass surface)
Poured dust weight
(1 liter)
Cone angle of heaped dust
Jogged dust density
UNIT
Degrees
g/dm
Degrees
g/cm
KIND OF DUST
CEMENT COAL TALC
After
sep.
41°50'
898.33
47°17'
1.40
Before
sep.
55°20'
7:6.67
48°09'
1.13
After
sep.
44°40?
571.67
41°49'
0.77
Before
sep.
62°
406.67
49°56'
0.62
After
sep.
90°
498.30
40°01'
0.87
Before
sep.
90°
446.70
61°45'
0.77
-------
Table 3. PARTICLE SIZE DISTRIBUTION OF CEMENT DUST
00
SEPARATED FOR
LABORATORY SCALE
Density: 2.86 g/cm
Range of
Particle
size in ion
0-2 . 13
2.13-3.91
3.91-5.92
5.92-9.17
9.17-14.20
14.20-23.67
23.67-28.99
28.99-32.54
>32.54
Percent
by weight
6.70
10.80
16.80
23.10
24.10
16.30
2.10
0.10
100.0
SEPARATED FOR
LARGE-SCALE
o
Density: 2.78 g/cm
Range of
Particle
size in urn
0-2.15
2.15-3.95
3.95-5.99
5.99-9.28
9.28-14.37
14.37-23.95
23.95-29.34
29.34-32.93
32.93-60
>60
Percent
by weight
11.91
18.90
30.19
24.89
10.46
3.02
0.43
0.07
0.13
100.00
SEPARATED FOR
LARGE-SCALE
0
Density: 2.857 g/cm
Range of
Particle
size in ym
0-2.17
2.17-3.97
3.97-6.02
6.02-9.34
9.34-14.46
14.46-24.09
24.09-29.52
29.52-33.13
>33.13
Percent
by weight
9.85
17.90
34.06
25.52
10.08
2.82
0.33
0.21
100.77
-------
Table 4. PARTICLE SIZE DISTRIBUTION OF COAL DUST
SEPARATED FOR
LABORATORY SCALE
3
Density: 1.55 g/cm
Range of
Particle
size in um
0-2.38
2.38-4.11
4.11-8.31
8.31-12.10
12.10-20.72
20.72-36.13
36.13-45.08
45.08-51.77
51.77-60
>60
Percent
by weight
7.15
13.86
30.20
21.51
23.88
3.21
0.09
0.02
0.01
0.07
100.00
iTON-SEPARATED FOR
LARGE-SCALE
o
Density: 1.48 g/cm
Range of
Particle
size in urn
0-2.95
2.95-5.41
5.41-8.19
8.19-12.70
12.70-19.67
19.67-32.78
32.78-40.16
40.16-45.08
45.08-60
60-88
88-150
150-200
>200
Percent
by weight
4.70
6.89
9.90
11.28
10.86
12.07
4.26
2.25
8.56
10.95
12.98
3.50
2.80
101.00
NON- SEPARATED FOR
LARGE-SCALE
Density: 1.50 g/cm
Range of
Particle
size in ]_im
0-2.42
2.42-4.18
4.18-8.44
8.44-12.29
12.29-21.06
21.06-36.72
36.72-45.82
45.82-52.62
52.62-60
60-88
88-150
350-200
-200
!
..
Percent
by weight
2.72
4.68
6.06
12.52
12.80
12.51
5.85
3.23
7 . 02
9.70
14.00
4.56
4.35
100.00 '
-------
Table 5. PARTICLE SIZE DISTRIBUTION OF TALC DUST
SEPARATED FOR
LABORATORY AND LARGE-SCALE
Density: 2.80 g/cm3
Range of
Particle
size in ym
0-2.15
2.15-3.95
3.95-5.99
5.99-9.28
9.28-14.37
14.37-23.95
23.95-29.34
29.34-32.93
^32.93
Percent
by weight
6.86
14.00
20.52
25.61
18.96
11.49
2.04
0.52
100.00
SEPARATED FOR
LARGE-SCALE -
3
Density: 2.78 g/cm
Range of
Particle
size in ym
0-1.77
1.77-3.05
3.05-6.17
6.17-8.98
8.98-15.39
15.39-26.83
26.83-33.47
Percent
by weight
4.93
11.39
17.14
41.37
22.45
2.72
100.00
-------
Table 6. CHEMICAL PROPERTIES OF TEST DUSTS
SEPARATED
CEMENT TEST DUST
Component
Loss by
roasting
Si02
Fe2°3
A12°3
CaO
MgO
so3
Na2°
K2°
Total
Percent
by weight
6.93
21.32
2.37
6.73
54.36
1.99
5.63
0.23
0.61
100.17
NON- SEPARATED
COAL TEST DUST
Component
Loss by
roasting
Si02
Ti02
A12°3
CaO
MgO
so3
Na£0
2
Total
Percent
by weight
25.51
51.13
0.92
8.58
22.96
6.91
2.62
3.21
0.88
2.35
99.56
r
SEPARATED
COAL TEST DUST
Component
Loss by
roasting
Si02
Ti°2
A12°3
CaO
MgO
so3
Na20
2
Total
Percent
by weight
24.14
46.75
1.04
10.46
22.78
8.25
3.34
4.42
0.85
1.81
99.70
-------
3.0 LABORATORY TESTS OF FILTRATION
This section describes the testing performed in the laboratory,
for both clean air flow and dust filtration. The results are presented
along with the conclusions which were drawn.
3.1 Equipment and Procedures
Laboratory testing of selected filtration fabrics was concluded
on a stand specially designed by the IPWMB and adapted for the testing
of flat fabric specimens under ambient air conditions. This stand is
shown in Figure 2.
Figure 2. Illustration of laboratory stand.
The testing stand includes the testing chamber, a rotameter for
measuring flow rate, a needle valve to control the flow, a vibrato-injecting
dust feeder, a micromanometer for pressure-drop measurements, and a vacuum
pump. These parts are illustrated in Figure 3. The testing chamber itself
22
-------
jj'LGW CONTROL VALVE
DUST FEEDER
AIR
OUTLET
FILTER CHAMBER
VACUUM PUMP
FILTER TE3T STAND
PAPER FILTER
IfcCLINED MAN(*lETERox
Figure 3. Diagram of the Laboratory Test Stand.
23
-------
is equipped with a diffuser at the inlpt end, a fabric specimen table,
and a control filter table at the outlet end. A round fabric specimen
2
with a test area of 100 cm was positioned in the middle of the table,
supported by wire net screening (4 cm on a side).
During testing, dusty air flows through the fabric from the top
downward. The inlet diffuser provides a uniform flow across the entire
test area of the fabric. After passing through the fabric specimen, the
air then passes through a control filter of soft batting and paper (a disc
2
with an area of 200 cm ) , which is positioned on the table at the outlet
end and is supported by wire net screening (1 cm on a side).
The average dust collection efficiency was determined by weighing
the fabric specimen and the control filter and applying the equation:
G G -G G
E = _z = c ° = *
E G G G + G (3>:L)
c c z o
where G = weight of dust collected on the fabric; G = weight of dust
z o
collected on the control filter; and G = weight of dust fed into the
testing chamber.
Temperature and humidity of the ambient air were recorded for 72 hours
during the test run.
With this stand data can be obtained on the mean filtration efficiency,
the flow characteristics of filtration materials during clean air flow,
rise in flow resistance during dusty air flow, and the degree of filling
of filtration materials. Although it was specially designed for the
laboratory testing of woven filtration fabrics, this stand can also be used
for laboratory testing of other materials, for instance, felt.
24
-------
3. 2 Results and Discussion
3.2.1 Air Flow Through Clean Fabrics
Filtration fabrics are changing porous media; their spatial
and surface structure can vary with the flow conditions. In general,
an increase of flow leads to an increased pressure drop, but the varia-
tions in the function
AP = f(q ), (3.2)
o
where AP is the static pressure drop and q is the gas loading on the
o
3 2
filtration area (m /m -hr), are connected with the spatial composition
of fabric structure and depend on structural parameters.
The structure of woven fabrics is much more complicated than of
non-woven ones. Just as in non-woven fabrics, the basic element of
structure is an elementary fiber of definite length and diameter. However,
fiber parameters do not directly determine structural properties. Individual
fibers make up the structure of yarn, and it is the manufacturing process
that determines the blend of fibers in the yarn. Finally, in woven
fabrics, the yarns are mutually crossed in definite patterns, and the flow
properties result from a combination of the yarn and the weave structures
Despite intensive investigations, the physical parameter structure,
which is related to all the technological parameters of fiber, yarn, and
fabric and the spatial composition of the fabric, has yet to be defined.
The coefficient K (flow resistance), which stems from Darcy's law,
has only a statistical sense with regard to flow through fabrics. It can
be used to examine the influence of the variation of individual parameters
on the flow resistance, but it does not provide a physical understanding
25
-------
of the filtration structure. As a result, it cannot be used in fabric
structure design or in prediction of flow characteristics.
Permeability is a quantity commonly used to classify woven filtration
media. It has been defined experimentally as the air flow rate per unit
area at a fixed pressure drop. In the USA, the pressure drop is standardized
at 0.5 inches of water, and in Poland at 20 mm (sometimes 10 mm) of water.
Measuring the permeability of one fabric at several different places enables
an estimate of the fabric homogeneity to be made; this is another qualitative
parameter used by filtration fabrics producers. The absolute value of the
permeability indicates the porosity of the spatial and surface structure.
From a mathematical point of view, permeability cannot be accepted
even as a statistical parameter for classifying woven fabrics, because
there could be infinitely many structures of differing compositions but
with the same permeability. The most important use is a comparison of the
functions AP = f(q ) at specific values. This is the reason for conducting
O
air flow experiments through clean filtration fabrics.
The results of these experiments are shown in Table B-l and in Figures
4 through 6. Photographs of the fabric surfaces indicating differences
in structure are shown in Figures A-4 through A-8.
Based on the technological parameters of yarn fabrics, the free-flow
area through each fabric was calculated by:
FA = I2 - (n_d 1 + n d 1 - n n d d ), (3.3)
°o ww owow \.-»-j;
where
1 = 10 cm,
n = number of threads in warp on 10 cm,
26
-------
12
10
o
CM
. 6
3
I I
O Polyester 08923
v Polyester C890B
a Polyester b65B
Polyester G868B
0 Polyester G866B
A Polyester fc62B
200
GAci LOADING Oi? FILTRATION AREA, in ra3/m2/hr
Figure 4. Flow Characteristics of Polyester Fabrics,
27
-------
o
CM
35
03
CO
v Cotton 960
0 Glass
Nylon 802B
A Glass Q53-878
D Glasa Q53-&75
200
GAS LOADING OP FILTRATION AREA, in m3/m2/hr
Figure 5. Flow Characteristics of Glass, Cotton and Nylon Fabrics.
a
•H
v Noraex 190
O Nome* 850
D Noaiex 853
h A Nomex 852
ffi
GAS LOADING OP FILTRATION AREA, in m
Figure 6. Flow Characteristics of Nomex Fabrics.
28
-------
n = number of threads in fill on 10 cm,
w '
d = diameter of warp yarn (cm), and
d = diameter of fill yarn (cm).
w
Diameters of the warp and fill yarns were calculated from the
metrical numbers according to:
(3.4)
X/NnT"
V o
and
w
X/Nrn"
v w
(3.5)
where Mm and Nm are the metrical numbers for the warp and fill yarns
o w J
respectively, and C is a characteristic constant, depending on the kind
of fiber (see Table 7).
Table 7. VALUES OF CHARACTERISTIC FACTOR "C1
Raw Materials
Cotton and staple viscose
Worsted wool: French System
British System
Carded wool
Polyamid silk, continuous polyester
and nomex
Staple polyester
Glass
C" Values
1.25
1.26
1.32
1.36
1.50
1.32
0.705
29
-------
Because of the large distortions in glass yarns, FA was calculated
by projected values of d and d . The results of these calculations are
o w
shown in Tabl*1 8. Values of FA for the ^Luup of fabrics tested range
between zero and 17.4 percent.
The specific values of FA serve to draw a curve (See Figure 7)
showing AP as a function of FA. The diagram was drawn for a filtration
3 2
area gas loading of q = 100 m /m -hr. It is easy to observe that points
c>
fall along two straight lines (in the range tested) , intersecting in the
region of FA = 5.5 percent and AP = 15 mm of water. Curve A shows a
decreasing dependence for increasing values of FA; this agrees with
intuition and is compatible with flow principles. Curve B shows an
increasing function for increasing values of FA, which seems to be con-
tradictory.
Analyzing the kinds of fabrics which fall along curves A and B,
we come to the following conclusions:
1. Curve A represents the variation of FA for Polyester Styles
865B, C868B, and 862B and for Nomex Style 850, 853, (852).
2. Curve B represents the variation of FA for Polyester Styles
C890B, C892B for Nylon Style 802B, and for Glass Style Q53-875,
Q53-878.
3. Cotton Style 960 and Glass Style Q53-870 lie outside the curves
because of principal differences in structure due to their
weave. They have not been considered here.
The dependence of curve A is characteristic of fabrics made from staple
fibers, while curve B is characteristic of continuous filament fabrics. The
inverse dependence of curve B is a result of a significant deformation of
30
-------
Table 8. FREE AREA FOR INVESTIGATED FABRICS
Kind of Raw Material
Cotton
•p
Dacron Polyester
(staple fiber)
Dacron Polyester
(continuous filament)
TJ
Nomex Aromatic Nylon
(staple fiber)
Nomex Aromatic Nylon
(continuous filament)
Nylon Polyamide
(staple fiber)
Glass
(staple fiber)
Glass
(continuous filament)
Type of
Filtration
Fabric
960
862B
C866B
C868B
865B
C890B
C892B
852
853
190
850
802B
Q53-875
Q53-870
Q53-878
Calculated Values
of "FA"
(In Percent)
0.969
13.326
9.731
4.514
0
8.048
13.256
17.422
5.984
5.148
6.650
1.578
1.066 *
3.292
For projected diameter of yarns,
31
-------
the yarn in the fabric structure, caused by the reduced friction between
the silky fibers. As a result, the true value of FA much lower than
the calculated one and the resistance to flow increases in inverse
proportion to the FA value, which is calculated from the technological
parameters and weave parameters. It seems that FA is not a representative
parameter for continuous filament or silk-type fabrics. Differences
in structure of staple and continuous filament fabrics are shown in
Table 8.
3.2.2 Laboratory Testing of Filtration Filters
The results of the laboratory tests conducted under this
project are shown in Tables 9 and 10. Figures A-19 through A-33 show
the increase of filter resistance during the filtration process. A
comparative analysis of the fabrics tested was conducted using these
results, for each raw material group, taking into consideration the
final filtration efficiency and its variation as a function of the gas
loading on the filtration area and also the final filtration resistivities
for a specific gas loading on the filtration area (q ) and for the
O
estimated dust loading of the filtration area (L ).
Cotton and Nylon Fabrics
The Cotton and Nylon Fabrics group was represented in these tests by
Styles 960 and 802B. These fabrics reached the highest values of
efficiency among all the tested fabrics. It is interesting to note that
Nylon Fabric Style 802B reached similar values of efficiency, independent
of type of dust and values of gas loading. Cotton Fabric Style 960
reached the highest efficiency, 99-99 percent, for talc at q =60 m3/m2-hr
O
32
-------
Table 9. LABORATORY EFFICIENCY (in percent) OF TESTED FILTRATION FABRICS
(Dust concentration of C =10 g/m3 and L = 400 g/m2)
o °
Type
of filtration
fabrics
Cotton
(staple filter)
Style No. 960
•D
Dacron polyester
(staple fiber)
Style No. 862B
Style No. C866B
Style No. C868B
Gas loading
of
filtration
area in
3 2
m /m /hr
60
80
60
80
60
80
60
80
Kind of dust
Separated
Cement
Dust
99.96
99.98
99.83
99.74
99.93
99.93
99.95
99.95
Separated
Coal
Dust
99.60
99.97
99.89
98.39*
99.93
99.93
99.92
99.94
Separated
Talc
Dust
99.99
99.99
99.87
98.96*
99.86
99.86
99.95
99.96
Non-Separated
Coal
Dust
99.68
98.74
99.93
99.91
99.95
99.92
UJ
U)
observed ducts/canals
-------
Table 9 (continued)
T5
Dacron polyester
(cont. filament)
Style No. 865B
Style No. C890B
Style No. C892B
p
Nomex aromat . nylon
(staple fiber)
Style No. 852
Style No. 853
Style No. 190
T>
Nomex aromat . nylon
(cont. filament)
Style No. 850
60
80
60
80
60
80
60
80
60
80
60
80
60
80
99.95
99.93
99.59
98.18
99.88
99.45
99.77
99.87
99.95
99.90
99.95
99.94
99.35
98.62
99.95
99.87
99.79
A
98.64
99.76
99.12
99.90
99.91
99.95
99.96
99.97
99.98
99.69
*
98.09
99.97
99.94
99.76
99.37
99.76
99.55
99.95
99-94
99.94
99.92
99.96
99.97
98.99
99.87
99.88
99.63
98.76
99.68
99.19
j
97.41 !
observed ducts/canals
-------
Table 9 (continued)
Nylon polyamide
(staple fiber)
Style No. 802B
Glass
(staple fiber)
Style No. Q53-875
Glass
(cont. filament)
Style No. Q53-870
Style No. Q53-878
60
80
60
80
60
80
60
80
99.96
99.96
A
97.54
*
84.63
*
95.03
A
86.38
*
94.51
A
85.11
99.96
99.99
98.60
*
82.18
A
93.03
A
85.05
A
96.12
A
78.32
99.97
99.97
A
88.21
A
70.32
A
93.65
A
85.97
A
91.74
A
80.81
CO
Ln
observed ducts/canals
-------
Table 10. FILTRATION RESISTANCE (in mm HO ) AT LABORATORY TESTS
3 2
(Dust concentration C = 10 g/m and L = 400 g/m )
Type
of filtration
fabrics
Cotton
(staple fiber)
Style No. 960
TJ
Dacron polyester
(staple fiber)
Style No. 862B
Style No. C866B
Style No. C868B
Gas loading
of
filtration
in
3 2
m /m /hr
60
80
60
80
60
80
60
80
Kind of dust
Separated
Cement
Dust
31.60
48.35
22.52
37.45
22.21
36.42
23.70
38.24
Separated
Coal
Dust
39.97
77.58
28.44
59.09
35.63
67.31
31.60
65.57
Separated
Talc
Dust
36.82
68.41
28.52
38.63
22.83
41.23
25.09
44.16
Non-Separated
Coal
Dust
18.86
41.00
20.35
46.05
21.27
48.82
-------
Table 10 (Continued)
R
Dacron polyester
(cont. filament)
Style No. 865B
Style No. C890B
Style No. C892B
T?
Nomex aromat. nylon
(staple filter)
Style No. 852
Style No. 853
Style No. 190
P
Nomex aromat. nylon
(cont. filament)
Style No. 850
60
80
60
80
60
80
60
80
60
80
60
80
60
80
32.31
60.99
43.06
66.05
58.86
99.22
20.22
38.71
18.80
38.24
20.29
37.32
44.64
73.79
40.93
77.42
63.60
107.76
66.99
126.56
31.44
59.72
30.89
65.65
29.48
66.36
53.56
99.86
35.15
71.73
54.12
95.43
60.91
113.60
23.46
47.80
26.33
47.87
27.34
50.09
47.40
92.75
25.15
65.41
42.58
93.38
45.35
100.01
j
-------
Table 10 (continued)
Nylon polyamide
(staple fiber)
Style No. 802B
Glass
(staple fiber)
Style No. Q53-875
Glass
(cont. filament)
Style No. Q53-870
Style No. Q53-878
60
80
60
80
60
80
60
80
21.68
36 . 18
43.45
63.04
59.09
88.32
33.58
44.71
29.15
59.33
54.04
64.46
58.46
92.43
45.51
49.53
20.79
46.61
34.13
39.50
58.70
79.95
30.18
40.61
00
NOTE:
Filtration resistance are average values of the final measured pressure drop of filtration cycles.
-------
3 2
as well as at q^ = 80 m /m -hr. Both fabrics demonstrate the increase
o
of filtration efficiency with the increase of gas loading on the
filtration area in tests conducted with separated coal dusts, supposedly
caused by electrostatic effects.
The high efficiency of these tested fabrics results from quite good
filling of the fabric structure with fibers and from application of
staple fibers to their production. Staple fibers favor a filling in of
free areas by "free fibers". The effect of "free fibers" on fabric
structure is illustrated in Figure 9.
The calculated values of FA are quite low for both fabrics:
0.969 percent for Fabric 960 and 6.650 percent for Fabric 802B.
Filtration resistances for Nylon Fabric 802B (as measured by the final
static pressure drop) are similar to those obtained for staple fiber
fabrics (Polyester and Nomex). However, cotton fabrics demonstrated
high filtration resistances, characteristic of this group of fabrics.
Polyester Fabrics
In this group of fabrics, the influence of staple fibers on
filtration efficiency and resistivity is easily observed. The lowest
values of efficiency were recorded for the continuous filament fabrics,
C890 and C892B, and for the staple fiber fabric 862B. The staple fiber
fabric 862B has a much more porous structure than other fabrics. Its
value of FA = 13.3 percent indicates little fill of structure, and at
3 2
a gas loading of q = 60 m /m -hr, the fabric reaches an efficiency of
5
the same level as other polyester fabrics. However, at a gas loading
of a =80 m3/m -hr, the filtration efficiency is decreasing. This is
8
caused by the formation of ducts/canals in the empty area between yarns
(see Figure 10).
39
-------
10
o
CM
33
g
ro
CQ
960
A Nomex (staple) V Cotton (staple)
A Nomex (fil.) O Nylon (staple) .
D Polyester (staple)
• Polyester (fil. )
O Glass
10 15
FREE AREA, in percent
o 7
Figure 7. Pressure Drop vs. FA for Clean Air Flow (q = 100 m /m /hr)
O
-------
a) Continuous filament
BI
b) Staple fibers
Figure 8. Comparison of cross-sections of threads with
continuous filament and staple fibers.
41
-------
! 1
= Area of calculated PA
d , d = Diameter of yarn (warp and fill)
o w
1,1 = Distance "between axes of yarns
o w
(along warp and fill)
Figure 9. Effect of "free fibers" on fabric structure.
42
-------
Figure 10. Surface of Dust Cake on Fabric 862B (dust
q = 80 m3/m2/hr).
O
talc,
43
-------
The mechanism of ducts/canals formation is dust cake structure
defects, as a result of pressure drop differences across an area
of loose filtration structure (with low endurance parameters). The
area of loose filtration structure is formed by "free fibers" which
are susceptible, to geometric formation.
The formation of ducts/canals in the filtration process was
also noted for the fabric C890B during testing with separated coal
dust. It can be caused by displacement of silky fibers with low
coefficients of friction. The other fabrics, 865B, C866B, and C868B,
have high efficiencies of about 99.95 percent and the decrease of
efficiency with increasing gas loading of the filtration arr••* is not
observed in the range of our tests. The filtration resistances of
continuous filament Polyester fabrics are twice as high as those of
staple fiber fabrics.
Laboratory testing of polyester fabrics were conducted with two
types of coal dust: separated, with MMD = 7.5 urn, and unseparated,
with MMD = 28 pm. Big differences in filtration efficiency were not
observed, but the filtration resistances with unseparated dusts were
30-45 percent lower than those with separated dusts. This is a result
of different structures of the dust cake formed during the fx;nation
process.
Nomex Fabrics
The results of testing the Nomex fabrics indicates they are on
the same level as Polyester fabrics. Fabric 850 (continuous filament)
appeared to have the lowest efficiency and highest filtration resistance
in this group.
44
-------
Glass Fabrics
labrics made with glass fibers reached the lowest values of
efficiency of all the fabrics tested in the laboratory experiments.
Fabric Q53-875 with staple fibers appeared to be the most efficient
one in this group. The low values of efficiency are caused by ducts/
canals formation, favoring the penetration of dust particles through
the filtration structure. The formation of free areas between yarns,
the direct cause of ducts/canals formation, is characteristic of glass
fabrics because glass fibers have very low coefficients of friction.
That is why threads and fibers displace during air flow, forming
"free areas". The influence of "free fibers" is limited by their
fragility, leading to considerable penetration of particles through
the filtration structure. Fabric samples with ducts/canals in the
dust cake are shown in Figures 11 through 13.
In the tests conducted r t coal dust, the counting of canals was
recommended. The number of ducts/canals at certain gas loadings is
shown in Table 11.
Table 11. NUMBER OF DUCTS/CANALS OBSERVED IN LABORATORY TESTING
(Testing of glass fabrics with separated coal dusts)
Kind
of fabric
Q53-875
Q53-870
Q53-878
Gas loading
of filtration
area
3 2
m /m /hr
60
80
60
80
60
80
Number
of
ducts/canals
—
102
16
42
7
69
45
-------
Figure 11. Surface of Dust Cake on Fabric Q53-875
(dust: talc, q = 80 m /m /hr).
&
46
-------
•
•
10x magnification
Figure 12. Surface of Dust Cake on Fabric Q53-870
(dust: cement, q = 80 m^/ir
o
47
-------
Figure 13. Surface of Dust Cake on Fabric Q53-878
(dust: cement, q = 80 m3/m2/hr).
48
-------
The data shown in Table 11 correspond with the filtration efficiencies
obtained. Fabric Q53-875, which reached the highest efficiency in the
3 2
group of 98.60 percent at q = 60 m /m -hr did not have any canals in its
o
3 2
surface. The existence of canals numbering N = 102 at q = 80 m /m -hr
5
reduced its filtration efficiency to 82.18 percent.
Because each stage of formation of the system filtration structure -
dust cake is correlated with a definite value of dust loading, L , in
grams per square meter and with a proportionate pressure drop, AP in mm
of water (which depend on the filter and dust properties), it is possible
to estimate experimentally a limiting AP value for the formation of
KK
ducts/canals, for a give type of dust. For instance, for Fabric Q53-875
and coal dust of MMD = 7.5 ym, the value of AP is 54 mm of water,
KK
2 32
corresponding to L = 400 g/m at q = 60 m /m -hr. Knowing the initial
concentration, it is possible to estimate the length of the filtration
process before the formation of ducts/canals, and consequently, the time
of operation of the filter at its highest efficiency. For other fabrics,
the gas loading of the filter which causes variations in the flow resistance
is so high that AP values are outside the range of our experiments.
KR
Filtration resistances for glass fabrics under these conditions are higher
than for Polyester and Nomex fabrics. The high resistances occur in
continuous filament glass fabrics (Q53-870).
It is interesting to note that application of texturized thread in
the fill of Fabric Q53-878 did not increase the efficiency, but only
caused a decrease in filtration resistance.
This comparative analysis concerns itself with Dust Filtration Type I,
characteristic of laboratory testing, and so cannot be the decisive estimator
49
-------
for the fabrics. Qualitative parameters obtained in large-scale testing,
where the dust filtration process is similar to that in industrial dust
collectors (Type III Dust Filtration), will be the decisive parameters
for the fabrics.
3.3 Conclusions
Using separated dusts under the given conditions of testing (q , L ),
the following fabrics can be regarded as satisfactory for cement, coal,
and talc from a qualitative point of view:
Cotton Fabric 960
Nylon Fabric 802B
Polyester Fabrics 865B, C866B, and C868B
Nomex Fabrics 190, 852, 853
Glass Fabric Q53-875
Polyester and Nomex Fabrics based on continuous filaments and
Fabric 862B with staple fibers reach satisfactory operation only at
3 2
gas loadings of the filter of q = 60 m /m -hr.
O
The testing conditions of the glass fabrics were too severe for
their structure, resulting in the formation of ducts/canals.
50
-------
4.0 LARGE-SCALE TESTING
4.1 Equipment and Procedures
Large-scale testing of EPA-selected filtration fabrics was conducted
on an apparatus specially designed by IPWMB (Single Compartment Baghouse).
This apparatus is illustrated in Figure 14.
Figure 14. Illustration of large-scale stand.
This apparatus includes the following (see Figure 14): a filter
chamber, collection hopper, dust feeder, fans, pipelines and valves, and
control and measurement system. The filter chamber is of cylindrical
form (diameter 700 mm and length 3520 mm) and is composed of four separate
elements, tightly connected together. This construction enables experiments
51
-------
to be conducted on filter bags of various length. The last element of
the filter chamber is the head, on which an optional mechanical regeneration
system can be installed. The collection hopper is in the lower part of
the filter chamber. The filter chamber itself is thermally insulated.
The bag, 710 to 3250 mm in length and 200 mm in diameter, was installed
eccentric, to the filter chamber axis because of the installation of a
radio-isotope probe for the measurement of dust-cake thickness deposited
2
on the bag. The total filtration area is 2.01 m , and the net area is
2
1.884 m . A diagram of the single-compartment baghouse with its control
and measurement system is shown in Figure 15.
The testing dust is delivered to the circulating air with a screw
dust feeder with a capacity of 0.5 to 15 kg/hr + 10 percent. A variable
gear regulates the capacity of the screw dust feeder. The single-compartment
baghouse is equipped with two fans. The main gas is a type MMW 14, used
for keeping an underpressure throughout the testing apparatus and causing
3
the flow through the filter chamber. It has a fan capacity of 1200 m /hr
at a pressure of 600 mm of water. The reverse air fan is a type WP 20/1,
used for reverse air flow (in a direction opposite Lo the gas flow during
3
filtration). It has a capacity of 1200 m /hr at a pressure of 300 mm of
water.
Sections of the reverse flow and circulation gases (filtered ^ are
equipped with type NP-27 electric heaters to assure dry filtration condi-
tions in the filter chamber. Control valves in the pipelines allow control
of the gas loading on the filtration area at the set test values and assure
a constant load on the fans. Some actions of the control system and the
52
-------
Ln
OJ
M EC HAN> ML J>H A K E R
~~" {VIBRATOR J~
DUST FEEDER
ELECTRIC HEATER
r~
INCLINED
MANOMETER
f
Figure 15. 'Diagram of the Large-Scale Test Stand.
-------
instruments of the single-compartment baghouse are remotely controlled
from a desk in the operations room.
The control system allows testing in a manual mode, or automatically
with one of three variations of filter bag regeneration: reverse air flow
regeneration, mechanical regeneration, or mechanical regeneration with
simultaneous reverse air flow.
The test apparatus is equipped with several measurement devices
and control-measurement sets for the recording of humidity of the gas,
temperature of the gas, rate of flow, static pressure, dust concentration
before and after the filter chamber, duration of particular filtration
cycles and the temperature and humidity of the air in the laboratory.
The general conditions of the experiments are summarized as:
1) The maximum length of the filter bag was 3500 mm.
2) The construction of the filter bag was as in Figure 17.
3) The dispersion medium was atmospheric air taken as is.
4) The regeneration mode was reversed air flow with mechanical
vibration, with only mechanical vibration on the last cycle
of measurement.
5) The regeneration cycle is shown in Figure 16.
6) The reverse air loading is 20 percent higher than the gas
loading during the filtration cycle.
7) The measurement of dust concentration after the filter chamber
was by an aspiration method. (In some measurements, the particle
size distribution was done with the use of an Andersen Impactor.)
8) Experiments on bags filled with dust were done by multiple
repetitions of the filtration-regeneration cycle.
54
-------
FILTRATION
CYCLE
DELAY
1
MINUTE
RE-
VERSE
15
SECONDS
DELAY
3
MINUTE
REGENERATION
CYCLE
FILTRATION
CYCLE
a) For research objectives
FILTRATION
CYCLE
DELAY
1
MINUTE
VIBRA-
TION
10 Sec.
20 Sec.
50 Sec.
DELAY
3
MINUTE
REGENERATION CYCLE
b) For final cycle.
Figure 16. Diagram of Regeneration Cycles,
55
-------
B
B
500
700
..7QP._.
3300
700
A-A
HIRE RING
B-B
FABRIC
K
2
$
8
^
5
, '0
\
\
Figure 17. Construction of Bags.
-------
Some of the steps involved with the control and measurement in
the large-scale experiments are enumerated below:
1) Weighing and hanging the clean filter bag.
2) Adjusting the rate of flow so that the gas loading was compatible
with established values.
3) Adjusting the rate of reverse air flow.
4) Repetitive measurements of the initial flow resistance of the
clean fabric at the set gas loading by switching on the air
flow.
5) Adjusting the set-point of the dust feeder.
6) Dusting of the filter bag to attain rough equilibrium. The
bag must be dusted for about 8 hours, with periodic regeneration
until APN is constant.
7) Weighing of the filter bag after the structure fills to determine
the degree of filling L^ (after regeneration):
weight of filled bag - weight of clean bag
N net test area
8) Experimental determinations of the bag dusting time and the final
resistance of the covered filter bag, AP , at a specific LQ:
weight of covered bag-weight of clean bag
o net test area
9) Conducting a measuring cycle for a specific L :
a) Dusting of the filter bag to coverage L in the predetermined
time t^,.
r 1
57
-------
b) Recording the increase in resistance (AP) in the time t - .
c) Stopping the dust feed.
d) Measuring the final resistance AP .
K
e) Switching off the air flow in the system.
f) Weighing of the dust which has fallen into the hopper by
gravity.
g) Regeneration of the filter bag in the desired mode.
h) Measuring the bag resistance after regeneration, AP .
i) Weighing the dust collected in the hopper after regeneration
of the filter bag.
Steps ji through j^ are repeated five times.
10) Measuring the average dust concentration after the filter chamber
during the fivefold dusting.
11) Removing the filter bag and weighing it to determine the degree
of filling after the fivefold dusting.
12) Repetition of hanging the bag and recording its initial resistance.
13) Repetition of these steps for the next value of dust loading L .
14) Changing the filter bag for the next value of gas loading, qg.
Dust samples for laboratory examination are taken from the dust feeder,
from the collection hopper after filtration but before regeneration, and
from the filter bag after regeneration. A dust sample for fractional
analysis should be taken from each new part of the dust fed to the feeder.
The filtration efficiency for the single-compartment baghouse at
fixed conditions was determined from weighing according to:
E =
where E is efficiency, G is the total weight of dust fed to the filter
58
-------
chamber, calculated from the dust balance or capacity of the feeder and
GQ is the weight of dust in the cleaned gas, from the measurement of
emissions.
4.2 Results and Discussion
Large-scale testing was begun using separated talc. Because of
the physical properties of this dust (see Table 2), we encountered several
difficulties in the realization of the designed testing program. The
most difficult problems were in keeping the inlet dust concentration
3
constant at 10 g/m + 10 percent and in preventing the dust from
precipitating in the installation.
In order to keep the low concentration of dust at the inlet of the
filtration chamber within its tolerance, we were forced to improve the
dust feeder installed on the test stand. The first step was to obtain
uniform dust feeding at a constant rate. Accordingly, continuous
pulverization was applied ir. the feeder. With individual calibrations
for the dust, this gave good results.
The next problem concerned the ability to quantitate the amount of
dust in each part of the test stand, due to its precipitation, and the
necessity of calculating the quantity of dust fed to the filter chamber
in order to determine the dust loading for each cycle. In order to do
that, we were forced to change the profile of some parts of the installation
in the path of the aerosol, from the point of the dust inlet to the pipe-
line to the point of emergence from the filtration chamber. The problem
of dust settling on the walls of the pipe leading to the filter chamber
was brought under control by the application of vibrators and a heating
assembly in the dust feeder.
59
-------
Although these problems were under control during the testing,
during some filtration cycles with talc the following effects were
observed:
1) Exceeding the tolerance level in the concentration for
tests at q =60 m3/m2-hr for Fabric: 853 (12.03 g/m3),
o
190 (11.87 g/m3), and 852 (11.60 g/m3).
2) Overrunning the desired dust loading, L , for the introductory
filling cycles, during the filling of the fabric. For the last
five measurement cycles, the values were at the proper level.
Tests conducted after this, using coal dust, were not affected
in this way.
These differences were not only a result of controlling the tests
at low concentrations in the inlet gas, but also from the different
properties of both dusts. In contrast to coal, with talc, it was very
difficult to keep the established of L because of the inconsistent
r o
character of the dust cake, because of the small range of particle sizes
(up to 20 ym) and the strong adhesion properties. Basing the target
3
value of L = 400 g/m on the pressure drop measured, very often at the
end of a cycle, a higher or lower value of L was obtained.
The results of large-scale testing are shown in Table 12 and Figures
18 through 21. The table contains mean values of filtration efficiency
and outlet concentrations, obtained over five measurement cycles after
reaching equilibrium (with reverse air flow regeneration). The figures show
the dependence of filtration efficiency as a function of gas loading on
the filtration area.
60
-------
Table 12. LARGE-SCALE EFFICIENCY OF TESTED FILTRATION FABRICS
3 2
(Dust concentration of C =10 g/m and L = 400 g/m )
o o
Type
of filtration
fabrics
Cotton
(staple fiber)
Style No. 960
T>
Dacron polyester
(staple fiber)
Style No. 862B
Style No. C866B
Style No. C868B
Gas loading
of
filtration
area in
3,2,,
m /m /nr
60
80
60
80
60
80
60
80
Kind of dust
Separated Talc Dust
Efficiency
in
percent
99.985
99.825
99.975
99.685
99.989
99.958
99.959
99.854
Outlet
concentration
in
g/m
0.0016
0.0148
0.0026
0.0330
0.0012
0.0047
0.0038
0.0131
Unseparated Coal Dust
Efficiency
in
percent
99.917
99.984
99.782
99.805
99.955
99.623
99.936
99.912
Outlet
concentration
in
g/m
0.0090
0.0016
0.0226
0.0181
0,0044
0.0037
0.0017
0.0100
-------
Table 12 (Continued)
t?
Dacron polyester
(cont. filament)
Style No. 865B
Style No. C890B
Style No. C892B
T>
Nomex aromat. nylon
(staple fiber)
Style No. 852
Style No. 853
Style No. 190
n
Nomex aromat . nylon
(cont. filament)
Style No. 850
60
80
60
80
60
80
60
80
60
80
60
80
60
80
99.966
99.947
99.964
99.966
99.911
99.307
99.963
99.864
99.983
99.928
99.992
99.944
99.996
99.995
0.0033
0.0050
0.0034
0.0032
0.0079
0.0658
0.0043
0.0126
0.0021
0.0069
0.0010
0.0051
0.0005
0.0004
99.986
99.994
99.950
99.972
99.957
99.976
99.989
99.974
99.718
99.979
99.989
99.978
99.959
99.989
0.0015
0.0006
0.0053
0.0027
0.0044
0.0024
0.0010
0.0024
0.0287
0.0019
0.0012
0.0021
0.0043
0.0010
-------
Table 12 (continued)
Nylon polyamide
(staple fiber)
Style No. 802B
Glass
(staple fiber)
Style No. Q53-875
Glass
(cont. filament)
Style No. Q53-870
Style No. Q53-878
60
80
60
80
60
80
60
80
99.996
99.842
99.951
99.952
99.597
99.690
99.889
98.876
0.0004
0.0155
0.0048
0.0046
0.0406
0.0304
0.0108
0.1123
99.815
99.986
99.896
99.895
99.817
99.783
99.678
99.501
0.0174
0.0015
0.0128
0.0099
0.0193
0.0223
0.0323
0.0495
u>
-------
-p
•a
Jfr
•p
8
o
0)
P.
§
M
O
M
K
M
separated talc
— unsep
10 g/m3
400 g/m2
60 80
GAS LOADING ON FILTRATION AREA (m5/m2/hr )
Figure 18. Efficiency vs. Gas Loading
of Filtration Area for
Cotton Fabric (Large-Scale Test)
64
-------
100
93,9
•H
ffi
99,8
O
b
0)
O
99,7
99,55
separated
unseparated
= 10 g/m3
= 400 g/m3
99,6
60
40
GAS LOADING ON FILTRATION AREA (m3/m2/W)
Figure 19. Efficiency vs. Gas Loading of Filtration Area
for Polyester Fabrics (Large-Scale Test)
65
-------
weight
-p
a
0)
0
^
0)
H
O
EFFIC
JPigxire 20.
60 SO
GAS LOADING ON FILTRATION AREA (m3/m2/hr)
Efficiency vs. Gas Loading of Filtration Area
for Nomex and Nylon Fabrics (Large-Scale Test)
66
-------
•P
C
«>
o
fc
0)
1
M
O
separated talc
—— unscparated coal
i 10
= 400 g/m2
Figure 21
60 80
GAS LOADIHG ON PII/TRATION AREA (m5/m2/hr)
Efficiency vs. Gas Loading of Filtration Area
for Glass Fabrics (Large-Scale Test)
67
-------
In the appendix, Figures A-34 through A-93 show the change of filtra-
tion resistance as a function of time for each kind of fabric, dust, and
gas loading. The detailed compilation of results will be enclosed in the
final report.
In order to conduct a comparison of the results, the fabrics were
ordered according to the outlet concentration in the following ranges:
3
less than .0025 g/m ,
.0025 - .01 g/m3,
3
.01 - .1 g/m , and
greater than .1 g/m .
Table 13 was organized with these criteria.
As shown in the table, the lowest outlet concentration was obtained
for four fabrics: Cotton Fabric 960, Nylon Fabric 802B, Nomex 190, and
Nomex 850 (continuous filament). For the first three fabrics, the results
are the same as in the laboratory testing. The very good results of
the Nomex 850 filtration fabric, which had the lowest value of efficiency
in the laboratory testing, can be explained by the packed structure of
the dust during the filtration process. This disagreement in rank between
the laboratory testing and the industrial scale testing was observed only
with the Nomex 850. The lowest efficiencies among the tested fabrics were
observed in the glass fabrics. Fabric Q53-875 showed the best filtration
properties in this group of fabrics, just as in laboratory testing. In
some cases, increased gas loading on the filtration area resulted in
increased outlet concentration. The preliminary results of these tests
will be the subject of further investigations in order to explain some
recorded events.
68
-------
Table 13. COMPARISON OF QUALITATIVE PARAMETERS OF FABRICS
Kind of
Dust
Talc
Coal
Gas
loading on
filtration
area
3,2,,
m /m /hr
60
80
60
80
Q
Outlet concentration in g/m
below
0.0025
960
C866B
802B
190
850
853
850
865B
C868B
190
852
960
865B
C892B
802B
190
852
850
853
0.0025 -
0.01
865B
862B
C868B
C890B
C892B
852
Q53-875
C866B
C890B
190
853
Q53-875
960
C866B
C890B
C892B
850
C866B
C868B
C890B
Q53-875
0.01 -
0.1
Q53-870
Q53-878
960
865B
862B
C868B
C892B
802B
852
Q53-870
862B
802B
853
Q53-875
Q53-870
Q53-878
862B
Q53-870
Q53-878
above
0.1
Q53-878
1
69
-------
4.3 Conclusions
Large-scale testing conducted with coal dust and talc confirmed the
necessity of conducting laboratory testing as a preliminary selection
process for filtration fabrics. The filtration efficiencies in large
scale testing are higher than those obtained in laboratory testing, due
to the filling of the spatial structure to equilibrium. For the testing
conditions (q , L ) and dusts given (separated talc, unseparated coal),
the following fabrics can be regarded as satisfactory from a quantitative
point of view:
For separated talc dust:
Polyester Fabrics C866B, C890B;
Nomex Fabrics 190, 850, 853; and
Glass Fabrics Q53-875;
For unseparated coal dust:
Cotton Fabric 960,
Polyester Fabrics 865B, C866B, C868B, C890B, C892B, and
Nomex Fabrics 190, 852, 850.
The Cotton 960 and Nylon 802B fabrics had satisfactory efficiencies for
3 2
separated talc dust at a gas loading of q = 60 m /m -hr.
o
70
-------
5.0 STUDY OF REGENERATION PROPERTIES OF FABRICS
5.1 Introduction
During the life of a fabric filter, the material exists in one of
three states: as clean fabric, which has not had any contact with the
dust or gas medium; as filled fabric, which has been in contact with
the dust or gas medium, but which was regenerated; and dust-covered
fabric, which is fully filled with dust and dust cake. The thickness
of the dust cake depends on the length of contact with the gas-dust
medium.
These stages of the filtration fabrics are characterized by separate
resistivities (static pressure drops) at specific values of gas loading:
AP = clean fabric resistivity,
AP = filled fabric resistivity, and
AP = dust-covered fabric resistivity.
K.
Following the principle of superposition, the following relation
holds:
APR = APN + APW , qg= const., (5.1)
where AP is the dust cake resistivity.
w
This relation shows the specific problems of a practical nature
connected with accurately measuring the fabric regeneration process. The
dust-covered fabric resistivity (the final resistivity of a filtration
cycle) is dependent upon the clean fabric resistivity, the physico-chemical
properties of the dust, and the gas loading.
71
-------
Figures 22 and 23 show the theoretical and actual course of the
filtration and regeneration processes in the bag filter, with signifi-
cant values indicated. In a theoretical run, at constant gas and
dust loading, the duration of filtration in a particular cycle is
constant, resulting in a final resistance in each cycle, AP , which is
Jx
constant. However, in actual conditions where the values characterizing
gas and dust loadings are variable in time and mean values only are used,
the distribution of the flow pressure drop is completely different
(Figure 23).
The duty life of a filtration fabric in a bag filter depends to a
large degree on the method of regulating the regeneration system. For a
given concentration, the final resistivity of dust-covered fabric should
attain a definite level AP . Multiple repetitions of filtration-regeneration
Jx
cycles lead to a certain increase of the filled fabric resistivity, measured
during regeneration. The increase tends toward a specific value, AP ,
for a given mode of regeneration, as a result of a fabric structure of
large specific area and thickness.
The fabric susceptibility for regeneration can be easily determined
by measuring this final value of resistance for a given mode of regeneration.
In order to compare filtration fabrics, the following equation for the
susceptibility for regeneration was developed:
AP - AP
Q _ , NK o
bR L APT, - AP (5'2)
K o
2 "} ?
at constant dust loading (q in g/m -hr), constant gas loading (q in m /m -hr)
3
and constant initial concentration (C in g/m ); AP and AP are defined as
72
-------
OJ
g
CO
to
TIME
Figure 22. Theoretical Run of Filtration and Regeneration Process.
-------
TIME
Figure 23. Practical Run of Filtration and Regeneration Process.
-------
Ui
a
CQ
co
TIME
Figure 24. Characteristic of Pressure Drop Values in Dust Filtration
Process.
-------
before, and AP is the final filled-fabric resistivity for a definite
mode of resistivity. The values of fabric susceptibility range from 0 to
100 percent.
5. 2 Results and Discussion
The estimation of regeneration properties for the group of fabrics
examined was conducted with values of the susceptibility for regeneration
calculated as above. Suitable values of pressure drop were taken from
data recorded during industrial scale testing and are shown in Tables
B-2 through B-9. The susceptibility was calculated for the fabrics after
four stages of regeneration:
1) after reverse flow regeneration, S ;
RR
2) after mechanical shaking (vibration) for 10 seconds, S ;
KMl
3) after mechanical shaking (vibration) for 20 seconds, S ; and
4) after mechanical shaking (vibration) for 30 seconds, S
The results of testing with specific gas loadings and dusts are shown in
Tables 14 through 17.
The susceptibility for regeneration, which is a property of the fabric
surface, depends to a large degree on adhesion effects at the interface
between the fabric and the dust cake. Thus, it depends on fiber properties
as well as on dust properties. The interaction of dust particles and fibers
(of solid state) is conditioned by different kinds of mechanisms. The
main mechanisms contributing to adhesion are molecular forces, electrostatic
forces, and capillary attraction. In dry filtration, the participation of
capillary forces is much weaker than electrostatic effects. Tests conducted
in our Institute confirm the large influence of electrostatic effects, not
only on filtration efficiencies, but also on their susceptibility for
regeneration.
76
-------
Table 14. Susceptibility for Regeneration of Fabrics
Tested with Talc Dust (in percent)(Gas load-
ing of filtration area q = 60 m^
o
Kind
of
Fabric
Style 960
Style 190
Style 852
Style 850
Style 853
Style 802B
Style 862B -
Style 865B
Style C866B
Style C868B
Style C890B
Style C892B
Style Q53-870
Style Q53-875
Style Q53-878
Susceptibility for Regeneration
SRR
67.3
82.7
86.3
64.3
43.4
70.3
81.1
79-2
77.1
68.9
70.2
75.3
66.3
77.6
73.9
SRM1
63.6
79.5
90.6
65.3
40.4
63.6
81.1
79.5
78.0
70.9
69.1
70.9
63.0
72.7
70.7
SRM2
61.4
78.7
89.8
65.1
38.2
63.2
82.7
79.5
74.8
69.4
71.3
73.9
63.0
79.1
70.7
SRM3
61.4
78.7
90.0
64.5
38.2
63.2
83.7
80.1
74.8
69.9
72.4
74.7
62.5
80.9
71.5
JRR
RM1
RM2
RM3
= reverse flow regeneration
= mechanical shaking during 10 sec
= mechanical shaking during 20 sec
= mechanical shaking during 30 sec
77
-------
Table 15. Susceptibility for Regeneration (in percent) of
Fabrics Tested with Talc Dust. (Gas loading of
filtration area q =80 m-V
Kind
of
Fabric
Style 960
Style 190
Style 852
Style 850
Style 853
Style 802B
Style 862B
Style 865B
Style C866B
Style C868B
Style C890B
Style C892B
Style Q53-870
Style Q53-875
Style Q53-878
Susceptibility for Regeneration
SRR
63.2
80.5
74.6
73.1
57.5
68.9
85.9
83.5
78.1
68.7
80.1
83.6
74.8
86.1
77.7
SRM1
61.3
78.5
54.9
69.5
57.3
64.8
83.8
77.8
73.4
62.2
71.7
85.2
71.3
79.2
74.2
SRM2
60.7
77.9
59.2
68.6
57.3
63.9
84.4
78.0
75.2
62.6
71.2
90.3
69.6
80.2
73.8
SRM3
60.7
78.5
60.6
68.9
57.3
64.8
85.0
78.6
77.1
63.7
71.9
91.7
69.9
83.5
74.2
RR
RM1
RM2
RM3
= reverse flow regeneration
= mechanical shaking during 10 sec
= mechanical shaking during 20 sec
= mechanical shaking during 30 sec
78
-------
Table 16.
Susceptibility for Regeneration (in percent) of
Fabrics tested with Coal Dust. (Gas loading of
filtration area q = 80 m3/m2/hr).
&
Kind
of
Fabric
Style 960
Style 190
Style 852
Style 850
Style 853
Style 802B
Style 862B •
Style 865B
Style C866B
Style C868B
Style C890B
Style C892B
Style Q53-870
Style Q53-875
Style Q53-878
Susceptibility for Regeneration
SRR
58.2
80.6
75.2
77.3
70.9
77.4
83.9
82.2
79.6
78.4
83.3
86.1
76.6
89.1
88.9
SRM1
55.4
77.5
73.2
74.0
68.4
75.3
83.9
75.9
78.7
78.0
83.3
85.5
69.2
84.3
85.8
SRM2
55.4
77.5
72.4
71.7
69.6
74.7
84.6
77.1
80.1
77.3
79.5
84.7
66.7
84.9
85.1
SRM3
55.4
77.5
73.2
70.0
69.6
75.3
85.0
78.3
81.5
77.3
78.6
84.7
64.7
85.5
85.1
RR
RM1
RM2
RM3
= reverse flow regeneration
= mechanical shaking during 10 sec
= mechanical shaking during 20 sec
= mechanical shaking during 30 sec
79
-------
Table 17. Susceptibility for Regeneration (in percent) of
Fabrics tested with Coal Dust. (Gas loading of
filtration area q = 80 m^/m2/hr).
o
Kind
of
Fabric
Style 960
Style 190
Style 852
Style 850
Style 853
Style 80 2B
Style 862B •
Style 865B
Style C866B
Style C868B
Style C890B
Style C892B
Style Q53-870
Style Q53-875
Style Q53-878
Susceptibility for Regeneration
SRR
62.8
84.1
84.2
77.4
76.3
75.7
84.5
86.6
83.1
80.7
85.9
83.1
84.2
88.4
92.2
SRM1
57.7
79.3
84.6
60.9
69.8
74.5
82.0
86.9
81.4
78.9
76.7
77.5
79-5
80.4
92.4
SRM2
56.5
80.9
82.7
64.6
68.3
74.5
82.9
85.9
81.6
80.3
75.4
73.9
79.5
80.4
91.8
SRM3
55.0
81.9
83.8
67.3
67.8
74.5
83.8
85.9
82.4
81.0
74.4
76.9
82.1
82.0
91.8
RR
RM1
RM2
RM3
= reverse flow regeneration
= mechanical shaking during 10 sec
= mechanical shaking during 20 sec
= mechanical shaking during 30 sec
80
-------
For preliminary interpretation of the calculated results of the
susceptibility, the following classifications were used:
1) Good - a susceptibility for regeneration of 80-90 percent.
2) Satisfactory - a susceptibility of 70-80 percent.
3) Bad - a susceptibility below 70 percent.
According to these criteria, the reverse air flow regeneration using
unseparated coal dust is ranked
Good for Fabrics 190, 862B, 865B, C890B, C892B, Q53-875,
and Q53-878;
Bad for Fabric 960; and
Satisfactory for the remaining fabrics.
Using separated talc dust, the ranking of fabrics is:
Good for Fabrics 190, 852, 862B, and 865B;
Bad for Fabrics 960, 850, 853, 802B, C868B, and Q53-870; and
Satisfactory for the remaining fabrics.
With mechanical regeneration alone, with a vibrator amplitude of 3 mm
at a frequency of 1400 per minute, the susceptibility for regeneration is
5-10 percent lower than with reverse air flow.
The considerably lower regeneration properties for the filtration of
the aerosol containing talc could be caused by the smaller MMD of talc
as compared with the MMD of unseparated coal dust. The differences between
the shape of the particles and the surface structure of the fabric are
also of great importance. These problems ought to be further investigated
and their results applied by filtration fabrics manufacturers.
5.3 Conclusions
For specific conditions of filtration and regeneration processes, an
estimation of the regeneration properties of fabrics can be obtained by
81
-------
measuring the pressure drops across the filter. An improvement in
regeneration effects for the fabrics can be obtained by increasing the
intensity of regeneration.
82
-------
6.0 CONCLUSIONS
Test measurements, conducted in laboratory and large scale
experiments on fifteen kinds of USA-manufactured filtration fabrics,
led to the following initial conclusions.
1) Although the dust filtration process characteristic of
laboratory testing is different from the process in large-
scale testing, fabrics which performed well in laboratory
testing were also found to perform well in large-scale
testing.
2) With clean air flow through filtration fabrics, FA calculated
from the technical parameters of the fabrics is a value
characterizing the fabric structure for staple fibers. For
continuous filament fabrics, FA is not a representative value
because of the deformation of structure.
3) Fabrics manufactured with silk-like fibers with low coefficients
of friction are very sensitive to increases in the gas loading
of the filtration area, leading to the formation of ducts/canals
and reducing their filtration efficiency (for certain experimental
conditions and fabrics).
4) Because the test conditions for the glass fabrics were too severe,
leading to the formation of ducts/canals, the efficiencies were
low and do not indicate the true filtration properties.
5) The regeneration properties depend on the materials of the fabrics
and dusts, and on the surface properties of structure, but do not
depend on the gas loading on the filtration area at which the
process was realized.
83
-------
7.0 RECOMMENDATIONS
Further research is deemed necessary. The completion of all cycles
of investigation will enable the definition of more detailed results,
especially in the comparison range between laboratory and large-scale
testing and in estimation of the regeneration properties of filtration
fabrics. The comparison of filtration and regeneration properties
between American and Polish fabrics is also foreseen.
The data obtained will be used in Project 5-533-5.
84
-------
APPENDIX A
85
-------
LIJ
N
Ul
h-
uu
t—
X
o
111
0,5
2345 10 20 30 40 50 100 200 300
PATRICLE DIAMETER, MICROMETERS
Figure A-1
Particle Size Distribution of Cement Tested
Dust (1 - for laboratory testing, 2 - for
large-scale testing)-
86
-------
2 3 4 5 10 20 30 40 50 IOC 200 300
PATffKLE DIAMETER, MICROMETERS
Figure A-2.
Particle Size Distribution of Coal Tested
Dust (1 - for laboratory testing, 2 - for
large-scale testing).
87
-------
-
'• ^/ ^-^X^.^:i^^^'--M.
LU
2345 ID 20 3D 40 50 ICC Z)D SCO
PATRICLE DIAMETER, MICROMETERS
figure A-3. Particle Size Distribution of Talc
Tested Dust.
88
-------
BJ i
Figure A-4. Surface of Glean Fabric Style 960
(cotton fiber).
89
-------
s-
*•• "'•„
'
fc
Figure A-5. Surface of Glean Fabric Style 662B
(polyester fiber)
90
-------
Figure A-6. Surface of Clean Fabric Style C866B
(polyester fiber)
91
-------
figure A-7. Surface of Clean Fabric Style CQ68B
(polyester fiber)
92
-------
- «
-•"•
••••.
*
gure A-8. Surface of Clean Fabric Style 865B
(polyester fiber)
93
-------
-*»• •••«"«
Figure A-9. Surface of Clean Fabric Style C890B
(polyester fiber)
94
-------
Figure A-10. Surface of Clean Fabric Style C892B
(polyester fiber)
95
-------
w"
-Jf
-
Figure A-11. Surface of Clean Fabric Style 852
(nomex fiber)
96
-------
Figure A-12. Surface of Clean Fabric Style 853
(nomex fiber)
97
-------
..".
(• "•/" ' •, • :%v" • ••^'•.••'f. :•'•:•
Figure A-13. Surface of Clean Fabric Style 190
(nomex fiber)
98
-------
Figure A-14. Surface of Glean Fabric Style 850
(nomex fiber)
99
-------
If I
Figure A-15. Surface of Clean Fabric Style 802B
(nylon fiber)
100
-------
Figure A-16. Surface of Clean Fabric Style Q53-875
(glass fiber)
101
-------
Figure A-17. Surface of Clean Fabric Style Q53-870
(glass fiber)
102
-------
Figure A-18. Surface of Clean Fabric Style Q53-878
(glass fiber)
103
-------
O separated cemeuu duat
ZX separated coal dust
D separated talc dust
= 60 m5/m2/h
= 80
10 20 30
FILTRATION TIME, in minutes
Figure A-19. Pressure Difference vs. Filtration
Time for Fabric Style 960.
104
-------
O separated cement dust
A. separated coal dust
D separated talc dust
V unseparated coal dtrat
= 60
q = 80 m5/m2/hr
D
Figure A-20.
10 20 30
FILTRATION TIME, in minutes
Pressure Difference vs. Filtration
Time for Fabric Style 862B.
105
-------
4)
70
O separated cement dust
A separated coal dus-t —
separated talc dust
unseparated coal dust
Figure A-21.
10 20 30
FILTRATION TIME, in minutes
Pressure Difference vs. Filtration
Time for Fabric Style C866B.
106
-------
50
0)
-p
•H
i
a
CO
O separated cement nu; L>
0 /O 20 30
FILTRATION TIME, in minutes
Figure A-22. Pressure Difference vs. Filtration
Tim© for Fabric Style C868B.
40
107
-------
70
o 60
£3
•H
O
50
S5 30
O separated cement dust
A separated coal dust
D separated talc dust
V unseparated coal dust/
-* O
a s 60 nr/m >
Ts x . P
q_ s 80
10 20 30
FILTRATION TIME, In miautee
Figure A-23* Pressure Difference vs. Filtration
Time for Fabric Style 865B.
108
-------
-------
O separated cement dust
A separated coal dust
separated talc dust
0
Figure A-25-
10 20 30
FILIATION TIME, in minutes
Pressure Difference vs. Filtration
Time for Fabric Style C892B.
110
-------
separated cement dust
separated coal dust
separated talc dust
60
= 80 m5/m2/hr
0
Figure A-26.
10 20 30
FILTRATION TIME, in minutes
Pressure Difference vs. Filtration
Pirne for Fabric Style 852.
ill
-------
80
70
£ 60
s
O separated cement dust
A separated coal dust
D separated talc dust
q_ = 60 m5/m2j
"/hr
0
Figure A-2?,
ID 20 30
PILTRADION TIME, in minutes
Pressure Difference vs« Filtraticwi
Time for Fabric Style 853.
112
-------
80
70
0
0
Q separated cement dust
A aeparated coal dual;
D separated talc dust
TL 2
q = 60 nr/m /hr
* ?
= 80 nr/a/far
10 20 30
PILTRATI01T TIME, in minutes
Figure A-28. Pressure Difference vs. Filtration
Time for Fabric Style 190.
113
-------
100
-p
co
CM
o
a
O
A
separated cement
separated coal
separated talc
q = 60 nr /Eif
60
a 80
Figure A-29,
10 20 30 <
FILTRATION TIME, in minutes
Pressure Difference vs. Filtration
Time for Fabric Style 850.
114
-------
separated ceutent dust
separated coal dust
separated tal
Q = 60 m-via /hr
l = 80 nrViu2/hr
u
ID 20 30
FILTRATION TIM3, in minutes
Figure A-30. Pressure Difference vs. Filtration
Time for fabric Style 802B.
115
-------
€>
-P
g
80
70
60
c
•H
« *
g
w
O separated cement dust
A separated coal dust
0
Figure
separated tele dust
q^ a 60 m^/ia /hr
* = 80
10 20 30
FILTRATION TIME, in minutes
Pressure Difference vs. Filtration
Time for Fabric Style
116
-------
separated cement
separated coal
separated talc
Figure A-32.
10 20 30
FUrTRATIQN HMBf in minutes
Pressure Difference vs. Filtration
Time for Fabric Style Q 55-870.
117
-------
50
fcl
o
43
I
O separated cement dust
/\ separated coal dust
G separated talc duet
7t p
a. s 60 m^/m /hr
o z p
« 80 ar/m Air
0
Figure A-35,
10 20 30
FILTRATION TUB, in minutes
Pressure Difference vs. Filtration
Time for Fabric Style Q 55-878.
118
-------
Dust: sep. Talc
100
400 ' 500 700 500 900
FILTRATION TIME, in minutes
Figure A-34. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric 960.
-------
•p
s
«H
O
c
-H
30
20
10
60 m3/m2/
400 g/m?
h-CQ « 10 g/m5
Dust: sep. Tal
ni
IV
0
100
200
300
700
500
900 1000 MOD
TIME, in minutes
Figure A-35. Pressure Difference vs. Filtration Time for
large-Scale Testing of Fabric 862B
-------
q = 60 m3/E!2/hr
Dust: sep. Talc
0
400 500 900 1000 1100
FILTRATION TIME, in minutes
(ZOO
Figure A-36. Pressure Difference vs. Filtration Time for
Large-scale Testing of Fabric C866B.
-------
NJ
|S5
SI
*H
O
q = 60 nrVmfyhr
LQ = 400
C_ « 10
Dust: sep. Talc
400 500 60D 700 800
FILTRATION TIKE, in minutes
.Figure A-37. Pressure Difference vs. Filtration Time for
Testing- of Fabric C368B.
-------
CO
0)
q,
*3
L"
60 m/m
400 g/m
(T » 10 g/m5
Dust: sep. Talc
1
DI
IV
D 100
Figure A-38.
200
300
400
500
600
700
800
900
FILTRATION TIME, in minutes
Pressure Difference rs. Filtration Time for
Large-Scale testing of Fabric 865B
-------
ro
.p-
Dust: sep. Talc
Figure A-39.
600 7QO 800 900
FILTRATION TIME, in minutes
Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric C890B.
1000
-------
4)
-P
05
40
g
20
10
$„=* 60 m5/m2/hr
L0 = 400 g/m*
CQ = 10 g/m5
Dust: sep. Talc
700 800 900 1000 1100
FILTRATION TIME, in minutes
Figure A-40. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric C892B.
1200
-------
1-0
= 400 g/m
Co = 10 g/m3 ~
Dust: sep. Talc
700 800 900 1000 1100
FILTRATION TIME, in minutes
Figure A-41. Pressure Difference vs. Filtration Time for
large-Scale Seating of Fabric 332.
-------
q = 60 m /m
&
L0 = 400 g/m
C = 10 g/m5
700 800 900 1000
FILTRATION TIME, in minutes
Figure A-42.
Pressure Difference vs. Filtration Time for
Large-Scale Testing og Fabric 85J.
-------
ro
oo
Figure 1-43.
400 500 600 700
FILTRATION TIMS* in minutee
Pressure Difference vs. Filtration Tis» for
Large-Scale Testing of Fabric 190.
-------
l-o
60 m3/m2/iir
400 g/m2
10 g/m3
set>. Talb
1000 1100 1200 1300 MOO
FILTRATION TIKE, in minutes
Figure A-44. Pressure Difference vs. Filtration Time for
large-Scale Testing of Fabric 850.
-------
o
f-
t)
•p
V4
O
I
7T p
q s 60 1ST/ID. /
I <= 400 g/m
100 200 300 400 500
FILTRATION TIME, in minutes
600
A-45. Pr«ae«r» Difference va. Filtration Time for
Testing of Fabric 602B.
-------
1900
PILCRAII08 f UK, la aimtee
Pressure Difference TS. Filtration Tint for
large-Scale feeting of Fabric 053-875.
-------
Co
400 g/m2
10 g/m5
Dust: a«p. Talc
900
FIMEATIQH TINE, in
Diff«roie« vs. Filtration Tine for
Larg»-Scmle Testing, of Fabric Q53-&70.
-------
UJ
OJ
Dust: sep. Talc
0 100
Figure A-48.
300
400
500 600 700 SOO
PILTRATIOU TIME, in minutes
Pressure Difference vs. Filtration Time for
I*rge-Sc*le Testing cf Fabric Q53-878.
-------
UJ
-O
L = 400 g/m2—
Dust: scp. Talc
D
300 400 500 600 700
FILTRATION TIME, in minutes
Figure A-49. Pressure Difference vs. Filtrtion Time for
Large-Scale Testing of Fabric 960
-------
Figure A-50.
300 400 500
FILTRATION TIME, in minutes
Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric 862B.
-------
a)
-------
oo
—I
-p
s
100
200 300 400 500 600
FILTRATION TIM3, in minutes
700
Figure A-52. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric C868B.
-------
OJ
oo
= So m5/m2/h|rDust
Ap0
0 100 200 300 400 500 600
FILTRATION TIME, in minutes
Figure A-53. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric 865B.
700
-------
0
100
200
300
800
900
FILTRATION TIMS, in minutes
Figure A-54. Pressure Difference vs. Filtration Time for
large-Scale Testing of Fabric C390B.
-------
o
q, = 80 m5/m2/t
"S
FILTRATION TIME, in minutes
Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric C892B.
-------
•p
ca
a!
ft*
too
200 300 400 500 600
FILTRATION TIME, in minutes
Figure A-56. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric 85?
-------
100
200
300 400 500 600
FILTRATION TIME, in minutes
Figure A-57. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric 853.
-------
LO
Dust: sep. Talc
FILTRATION TIME, in minutes
Figure ^-58. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric 190.
-------
L0 = 40C Km —
= 10
Dust: sep. Talc
0
200
300 400 500 600 700
FILTRATION TIME, in minutes
Figure A-59. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric 850.
800
900
-------
-O
Ul
Figure A-60.
200 300 400 500
FILTRATION TIME, in minutes
Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric 802B.
-------
Dust: sep. Talc
0
200 300 400 500 600
FILTRATION TIME, in minutes
700
Figure A-61. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric Q53-875.
-------
80 m5/m2/h
400 g/m2
10 g/m5
aep. Talc
Ap,
6 IOD
Figure A-62.
200 300 400 500 600
FILTRATION TIME, in minutes
Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric Q53-370.
-------
00
Dust: sep.Talc
0
too
300 400 500
FILTRATION TIME, in minutes
Figure A-63. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric Q53-878.
-------
40 r
p
30
I •* . 2 J
q = 60 nr/m /nr
LQ « 400 g/m2
-C0 = 10 g/m5
Dust: uneep. Coal
« 20
II 111
IV
/
100 200
300 800 900 IDOO IIOO
FILTRATION TIME, in minutes
I200 I300
Figure A-64. Pressure Difference va. Filtration Time for
Large-Scale Testing of Fabric 960.
-------
t-1
(_n
O
«H
O
C3
•H
q = 60 m5/m2/hr
L. = 40Q g/m2
C =10 g/m5
o
Dust: unsep. Coal
(00
200
400 500 600 700
FILTRATION TIM, in minutes
600
900
figure jk-65. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric &62B.
-------
g
c
•H
. 30
o
20
10
CM
TP O I
q^ = 60 mj/m /hr
L^ » 400 g/aa2
C =10 g/m
o
Dust: unsep. Coal
II
r
in
/I
A
IDO 200 300 600 700 800 900
FILTRATION TIME, in minutes
1000
IfOO
Figure A~66. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric C666B.
-------
s
q = 60 m5/m2/hr
Dust: unsep. Coal
e
500 600 70D SOO 900
FILTRATION TIME, in minutes
Figure A-67. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric C868B.
-------
Dust: unscp. Coal
400 600 800 1000 1200
FILTRATION TIME, in mixret*8
Vigur* A-68. Pressure Difference vs. Filtration Time for
fc*rge-3c*le Testing of Fabric S65B.
-------
(Jl
V
-p
cti
L° = 400 ts/rn
-C » 10 ,
\J
Dust: unsep. Coal
200
400 600 SOQ 1000 1200
FILTRATION TIME, in minutes
Figure A-69. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric C890B.
-------
I i3
a * 60 nr/m /hr
L « 400 g/m2
10 g
60
o
CO
CM
20
i
w
Bast: unsep. Coal
/I
7
IV
200 1000 1200 1400 1600 2000 2200
FILTRATION TIME, in minutes
2400
Figur« A-70. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric C892B.
-------
4)
-P
8
Dust: unsep. Coal
30D 400 5DD 1500 1600
FILTRATION TIME, in minutes
Figure A-71. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric 852.
-------
«H
o
6 20
n
Q
£ 10
= 60
5
L = 400 g/m
C « 10 g/m5
0
Duat: unsep. Coal
II 111
V VI
0
IDO
200 300 700 300 900 1000
FILTRATION TIME, in minutes
1100
Figure A-72. Preesure Difference vs. Filtration Time for
Large-Scale Testing of Fabric 853.
-------
00
cO
«H
O
30
O
125
0
q = 60 m^/ni^/hr
L = 400 r/m2
o
GQ = 10 ,:;/m^
Dust: unsep. Coal
IOO
200 300 400 500
FILTRATION TIME,
600 700
minutes
800
900
figure A-73. Pressure Difference vs. Filtration Time for
Lar^e-Scale Testing of Fabric 190.
-------
(Jl
AP
0
700
900
Figur* A-74.
IIOO (500 1700 1900 2100
FILTRATION TIKE, in minutes
Pressure Difference vs. Filtration Time for
large-scale Testing of Fabric 850
2300
2500
-------
M
O
+»
03
«H
O
20
q.,r = 60 m5/in /hr
LQ = 400 g/m°
"co = 1° *'
Thist: unsep. Coal
Figure A-75
500 900 1000 1100
FILTRATIOK TIME, in minutes
Pressure Difference vs. Filtration lime for
Large-Scale Testing of Fabric 802B.
1200
1300
-------
fc
pq
CO
50
20
10
Ap,
(
q « 60 m
LQ * 400
-C0 - 10 g
Bust: uns
Coa
yi
/
—
/
— "•
1
/
— •
W/]
g/m
/ 3
/m'
«p.
1
A
— •
•
^i^^
J tOO 200
/
1
I
/
/
/
/
/
V
11
/
/
n
,/
/
IV
/
f
1
V
/I
/
3
600 TOO 800 900 1000 HDD 7200
Figure A-76.
FILTRATION TIME, in minutee
Diff*renc« vs. Filtrmtion Time for
Larg«-Scal« Teetiiig of Fabric
-------
4)
-P
e
C
•H
a 60
o
qT = 60 m^/m /jh
•-" / P '
L = 400 g/n
C = 10 g/m3
Dust: unsep.
Coal
III
IV
100 200 900 (ODD IIOO 1200 1300
FILTRATION TIME, in minutes
MOO
(500
Figure A-77.
Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric 053-870.
-------
OJ
Dust: unsep.
Coal
Figure A-78.
700 SOO 900 1000
FILTRATION TIME, in minutes
Pressure Difference TS. Filtration Time for
large-Scale Testing of Fabric Q55-878.
1300
-------
Dust: unsep. Coal
200 300 400 500 600
FILTRATION TIME, in minutes
Figura A-79.
Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric 960.
-------
qg = 80
LQ = 400 g/m2
«= 10 g/m5
Dust: uns«p. Coal
0
Figure
200 300 400 500 600
FILTRATION TIME, in minutes
Pressure Difference vs. Filtration Time for
large-Scale Testing of Fabric 862B.
TOO
-------
ON
q = 80 ai5/m2/hr
= 400 g/m2
Dust: unsep. Coal
300 400 500 600
FILTRATION TIME, in minutes
Figure A^-81 . Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric G866B.
-------
*)
-P
I
Dust: unsep. Coal
200 300 400 500 600
FILTRATION TIME, in minutes
Figure A»82. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric C868B.
-------
00
q, = 80 m5/:r.2/hr
0
200 300 400 500 600
FILTRATION TIME, in minutes
700
8DD
900
Figure A-&JJ. Pressure Difference vs. Filtration Time for
Large-Scale Test-inxr of Fabric S65B.
-------
Dust: unsep. Coal
700 SOD 900
FILTRATION TIME, in minutes
1000
1100
1200
Figure A-84. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric C890B.
-------
-J
o
at: unsep. Costl
300 400 500 600 700
JILIEATION TIME, in minutes
Figure A-85. Presaure Difference V3. Filtration Time for
Large-Scale Testing of Fabric C892B.
900
-------
LQ = 400 g/m2
CQ = 10 g/m5 _
Dust: unsep. Coal
0
IOO
300 400 500 600
FILTRATION TIME, in minutes
Figure A-86. Pressure Difference vs. Filtration Time for
Large«*Scale Testing of Fabric 852.
-------
fc
e
•p
«M
O
80 ra5/m2/hr
400 ?/m2 —
CQ = 10 ^/V
Dust: unsep. Coal
200
300 400 500 600
FILTRATION TIME, in minutes
700
Figure A-87. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric 853.
-------
UJ
tt 30
P
0
q = 80 E
LQ = 400
G a 10
2
Dust: unsep. Coal
100 200 300 400 500 600
FILTRATION TIME, in minutes
700
Figure A-88. Pi-eaaure Difference vs. Filtration Time for
Large-Soale Testing of Fabric 190.
-------
60
g . 2
,Q = 400 g/mc
C - 10 g/m3
Dust: unsep. Coal
J I
300 500 600 700 SOO
FIJ/TRATION TIME, in minutes
Pigur« A-89. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric 850.
1000
-------
Dust: unsep. Coal
200 300 400 500 600
FILTRATION TIME, in minutes
Figure A-90. Pressure Difference vs. Filtration Time for
Large-scale Testing of Fabric 802B.
-------
100
200 300 500 600 700
FILTRATION TIME, in minuteB
800
900
1000
Figure A-91. Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric Q53-875.
-------
-p
8
—c
*s
80 m
400 g/m2
10 g/m3
/hr
Duat: tmsep.
Ooal
III
IV
0
IOO
200 300 700 800 900
FILTRATION TIB5E, in minutes
IOOO
IIOO
/200
Pigtire A-92.
Pressure Difference vs. Filtration Time for
Large-Scale Testing of Fabric Q53-870.
-------
-J
oo
LQ = 400 g/m
—C = 10 g/m3
0 IOO 200 300 600 700 6DD 900
FILTRATION TIME, in minutes
Figure A-93. Pressure Difference vs. Filtratior Time for
Large-Scale Testing of Fabric Q53-878.
flODO
-------
APPENDIX B
179
-------
Table B-l. Pressure Drop (in mm of water) vs. Gas Loading of Filtration Area for Pure Fabrics
Kind
of
Fabric
960
Average
862B
Average
Gas loading of filtration area in m-Vm^/hr
50
2.77
3.08
2.84
3.16
2.84
2.94
0.16
0.16
0.16
0.19
0.16
0.17
60
3.63
3.79
3.40
3.87
3.48
3.63
0.19
0.19
0.19
0.22
0.19
0.20
80
5.29
5.29
4.98
5.61
5.06
5.25
0.25
0.25
0.28
0.32
0.28
0.28
100
7.11
7.27
7.03
7.90
7.19
7.30
0.35
0.38
0.38
0.44
0.38
0.39
120
8.85
9.64
9.09
10.19
9.32
9.42
0.51
0.51
0.51
0.60
0.54
0.53
140
10.83
11.77
11.14
12.32
11.38
11.49
0.66
0.66
0.66
0.79
0.70
0.69
160
12.72
13.98
13.04
14.54
13.19
13.49
0.79
0.82
0.82
0.95
0.82
0.84
180
14.62
16.04
14.85
16.59
15.01
15.42
0.92
0.95
0.95
1.11
0.98
0.98
Conditions
Tern.
°C
20
21
Rel.
Hum.
%
47
43
Atm.
Press .
mmHg
745
747
oo
o
-------
Table B-l (Continued)
Kind
of
Fabric
C866B
Average
C868B
Average
3 ?
Gas loading of filtration area in m /mz/hr
50
0.40
0.40
0.47
0.40
0.32
0.40
0.79
0.71
0.63
0.63
0.63
0.68
60
0.47
0.47
0.55
0.47
0.40
0.47
0.87
0.87
0.79
0.79
0.79
0.82
80
0.63
0.71
0.79
0.71
0.55
0.68
1.26
1.26
1.19
1.11
1.11
1.19
100
0.95
0.95
1.11
0.95
0.71
0.93
1.74
1.66
1.58
1.50
1.50
1.60
120
1.26
1.26
1.50
1.34
1.03
1.28
2.29
2.21
2.13
1.98
2.05
2.13
140
1.58
1.58
1.98
1.74
1.34
1.64
2.92
2.84
2.69
2.45
2.61
2.70
160
1.90
1.90
2.29
2.05
1.58
1.94
3.56
3.40
3.16
2.92
3.08
3.22
180
2.29
2.21
2.69
2.45
1.82
2.29
4.11
3.95
3.63
3.40
3.63
3.74
Conditions
Tern.
°C
20
23
Rel.
Hum.
%
42
47
Atm.
Press .
nnnHg
748
742
oo
-------
Table B-l (Continued)
Kind
of
Fabric
865B
Average
C890B
Average
3 2
Gas loading of filtration area in m /m /hr
50
0.63
0.79
0,79
1.03
0.95
0.84
1.19
1.03
1.03
1.26
0.95
1.09
60
0.95
1.03
1.03
1.26
1.19
1.09
1.42
1.26
1.26
1.50
1.19
1.33
80
1.26
1.50
1.50
1.90
1.82
1.58
2.05
1.74
1.82
2.13
1.58
1.86
100
1.90
2.21
2.21
2.69
2.61
2.32
2.69
2.29
2.37
2.37
2.13
2.37
120
2.53
2.84
2.84
3.48
3.40
3.01
3.48
2.92
3.00
3.63
2.69
3.14
140
3.00
3.48
3.48
4.19
4.11
3.65
4.19
3.48
3.63
4.35
3.24
3.78
160
3.48
3.95
3.95
4.99
4.82
4.24
5.06
4.11
4.27
5.21
3.79
4.49
180
3.95
4.66
4.74
5.61
5.53
4.90
6.00
4.98
4.98
6.16
4.42
5.31
Conditions
Tern.
°C
20
22
Rel.
Hum.
%
47
35
Atm.
Press.
mmHg
745
742
00
M
-------
Table B-l (Continued)
Kind
of
Fabric
C892B
Average
852
Average
3 2
Gas loading of filtration area in m /m /hr
50
1.50
1.50
1.66
1.74
1.90
1.66
0.16
0.19
0.22
0.19
0.19
0.19
60
1.82
1.82
2.13
2.21
2.37
2.07
0.24
0.25
0.25
0.22
0.25
0.24
80
2.61
2.69
3.00
3.08
3.32
2.94
0.32
0.35
0.38
0.35
0.35
0.35
100
3.48
3.79
4.03
4.03
4.58
3.98
0.47
0.47
0.51
0.44
0.47
0'.47
120
4.50
4.82
5.21
5.21
5.77
5.10
0.55
0.60
0.66
0.60
0.63
0.61
140
5.53
5.77
6.32
6.56
7.19
6.27
0.71
0.79
0.85
0.76
0.79
0.78
160
6.64
6.79
7.66
7.74
8.53
7.47
0.87
0.92
1.01
0.89
0.95
0.93
180
1 .Ik
7.82
8.77
8.93
10.03
8.63
1.03
1.11
1.14
1.04
1.07
1.08
Conditions
Tern.
°C
22
23
Rel.
Hum.
. %
35
53
Atm.
Press.
mmHg
742
746
00
-------
Table B-l (Continued)
Kind
of
Fabric
853
Average
190
Average
3 2
Gas loading of filtration area in m /m /hr
50
0.63
0.79
0.63
0.63
0.55
0.65
1.11
1.19
1.03
1.11
1.11
1.11
60
0.79
0.95
0.79
0.79
0.71
0.81
1.34
1.42
1.26
1.42
1.34
1.36
80
1.11
1.42
1.11
1.19
1.03
1.17
1.90
2.05
1.82
1.97
1.98
1.94
100
1.50
1.83
1.42
1.50
1.34
1.52
2.53
2.77
2.45
2.61
2.61
2.59
120
1.98
2.45
1.90
2.05
1.74
2.02
3.32
3.63
3.24
3.40
3.40
3.40
140
2.37
3.00
2.29
2.53
2.12
2.46
4.03
4.42
3.95
4.19
4.19
4.16
160
2.84
3.56
2.77
3.00
2.61
2.96
4.74
5.14
4.58
4.90
4.90
4.85
180
3.24
4.11
3.08
3.40
2.92
3.35
5.37
5.93
5.29
5.61
5.61
5.56
Conditions
Tern.
°C
23
23
Rel.
Hum.
%
48
54
Atm.
Press.
mmHg
750
746
oo
-------
Table B-l (Continued)
Kind
of
Fabric
850
Average
802B
Average
3 2
Gas loading of filtration area in m /m /hr
50
0.63
0.63
0.63
0.63
0.63
0.63
0.87
0.79
0.79
0.87
0.95
0.85
60
0.79
0.79
0.79
0.79
0.79
0.79
1.03
0.95
0.95
1.03
1.11
1.01
80
1.11
1.11
1.11
1.19
1.11
1.13
1.50
1.34
1.34
1.50
1.58
1.45
100
1.50
1.50
1.50
1.58
1.50
1.52
1.98
1.74
1.82
2.05
2.13
1.94
120
1.98
1.98
1.98
2.13
2.05
2.02
2.69
2.29
2.45
2.69
2.92
2.61
140
2.53
2.45
2.45
2.61
2.53
2.51
3.40
2.92
3.00
3.40
3.63
3.27
160
3.00
2.92
2.92
3.00
2.92
2.95
4.03
3.48
3.63
4.03
4.35
3.90
180
3.63
3.32
3.32
3.48
3.40
3.43
4.66
3.95
4.19
4.66
4.98
4.49
Conditions
Tern.
°C
23
23
Rel.
Hum.
. %
48
47
Atm.
Press.
mmHg
750
742
00
-------
Table B-l (Continued)
Kind
of
Fabric
Q53-875
Average
Q53-870
Average
3 2
Gas loading of filtration area in m /m /hr
50
0.22
0.22
0.22
0.22
0.22
0.22
1.90
1.90
1.90
1.90
1.90
1.90
60
0.28
0.32
0.25
0.25
0.28
0.28
2.21
2.21
2.21
2.21
2.21
2.21
80
0.41
0.44
0.38
0.38
0.41
0.40
3.32
3.48
3.32
3.32
3.48
3.38
100
0.54
0.57
0.51
0.54
0.57
0.55
5.06
5.06
4.74
4.90
5.06
4.96
120
0.76
0.79
0.73
0.76
0.79
0.77
6.64
6.64
6.32
6.48
6.64
6.54
140
0.95
0.98
0.89
0.92
1.01
0.95
8.22
8.06
7.90
7.90
8.06
8.03
160
1.11
1.14
1.07
1.11
1.17
1.12
9.64
9.48
9.32
9.48
9.64
9.51
180
1.26
1.33
1.26
1.30
1.33
1.30
11.22
11.06
10.74
10.90
11.06
11.00
Conditions
Tern.
°C
25
26
Rel.
Hum.
. %
50
38
Atm.
Press.
mraHg
747
747
00
-------
Table B-l (Continued)
Kind
of
Fabric
Q53-878
Average
3 2
Gas loading of filtration area in m /m /hr
50
0.35
0.35
0.38
0.35
0.38
0.36
60
0.44
0.44
0.47
0.44
0.44
0.45
80
0.66
0.63
0.70
0.60
0.69
0.66
100
0.92
0.89
0.95
0.95
0.98
0.94
120
1.26
1.20
1.30
1.26
1.33
1.27
140
1.61
1.55
1.65
1.61
1.65
1.61
160
1.92
1.83
1.98
1.96
1.98
1.93
180
2.24
2.17
2.34
2.28
2.31
2.27
Conditions
Tem.
°C
25
Rel.
Hum.
%
50
Atm.
Press.
mmHg
747
00
-------
Table B-2. Characteristic Pressure Drop (in mm water) For
Reverse Air Flow Regeneration (dust: separated
talc, q = 60 m3/m2/hr, C = 10g/m3).
Kind Of
Fabric
Style 960
Sytle 862B
Style C866B
Style C868B
Style 865B
Style C890B
Style C892B
Style 852
Style 853
Style 190
Style 850
Style 802B
Style Q53-875
Style Q53-870
Style Q53-878
APK
26.80
20.20
22.20
22.00
34.40
49.10
38.10
19.64
14.70
14.10
36.60
23.60
50.60
41.40
38.30
AP0
4.00
0.60
0.80
1.40
1.30
2.80
1.70
0.60
1.10
1.40
1.40
2.70
0.80
2.50
1.10
APNK
11.45
4.28
5.70
7.83
8.15
16.60
10.73
3.15
8.80
3.95
13.97
8.90
11.98
15.63
10.83
188
-------
Table B-3. Characteristic Pressure Drop (in mm water) For
Mechanical Regeneration (dust: separated talc,
qg = 60 m3/m2/hr, CQ = 10 g/m3).
Kind Of
Fabric
Style 960
Sytle 862B
Style C866B
Style C868B
Style 865B
Style C890B
Style C892B
Style 852
Style 853
Style 190
Style 850
Style 80 2B
Style Q53-875
Style Q53-870
Style Q53-878
APRM1
12.3
4.3
5.5
7.4
8.1
17.1
12.3
5.1
9.2
4.0
13.6
10.3
14.4
16.9
12.0
APRM2
12.8
4.0
6.2
7.7
8.1
16.1
11.2
5.5
9.5
4.1
13.7
10.4
11.2
16.9
12.0
APRM3
12.8
3.8
6.2
7.6
7.9
15.6
10.9
5.4
9.5
4.1
13.9
10.4
10.3
17.1
11.7
189
-------
Table B-4.
Characteristic Pressure Drop (in mm water) For
Reverse Air Flow Regeneration (dust: separated
talc, q^ = 80 m3/m2/hr, C0 = 10 g/m3).
g
0
Kind Of
Fabric
Style 960
Sytle 862B
Style C866B
Style C868B
Style 865B
Style C890B
Style C892B
Style 852
Style 853
Style 190
Style 850
Style 802B
Style Q53-875
Style Q53-870
Style Q53-878
APK
37.50
34.20
33.00
28.60
40.80
60.50
45.60
22.40
22.50
16.80
63.90
23.80
54.50
80.60
51.90
APo
5.70
0.80
1.10
2.40
2.10
4.30
2.40
1.10
1.90
1.90
2.50
1.90
1.10
3.20
1.10
APNK
17.35
5.50
8.08
10.60
8.50
15.45
9.53
6.45
10.65
4.83
19.00
8.70
8.50
22.70
12.63
190
-------
Table B-5. Characterization Pressure Drop (in mm water) For
Mechanical Regeneration (dust: separated talc,
qo = 80 m3/m2/hr, C = 10 g/m3).
Kind Of
Fabric
Style 960
Sytle 862B
Style C866B
Style C868B
Style 865B
Style C890B
Style C892B
Style 852
Style 853
Style 190
Style 850
Style 802B
Style Q53-875
Style Q53-870
Style Q53-878
APRM1
18.0
6.2
9.6
12.3
10.7
20.5
8.8
9.6
10.7
5.1
21.2
9.6
12.2
25.4
14.2
APRM2
18.2
6.0
9.0
12.2
10.6
20.5
6.6
9.8
10.7
5.2
21.8
9.8
11.7
26.7
14.4
APRM3
18.2
5.8
8.4
11.9
10.4
20.1
6.0
9.5
10.7
5.1
21.6
9.6
9.9
26.5
14.2
191
-------
Table B-6.
Characteristic Pressure Drop (in mm water) For
Reverse Air Flow Regeneration (dust: unsep. coal,
q = 60 m3/m2/hr, r = 10 g/m3).
8
0
Kind Of
Fabric
Style 960
Sytle 862B
Style C866B
Style C868B
Style 865B
Style C890B
Style C892B
Style 852
Style 853
Style 190
Style 850
Style 802B
Style Q53-875
Style Q53-870
Style Q53-878
APK
28.6
28.9
22.7
28.3
26.9
35.5
51.5
25.4
22.0
17.6
41.0
20.2
51.1
58.0
42.4
Apo
3.5
0.9
1.1
1.9
1.6
1.4
3.3
0.8
1.4
1.6
1.4
1.6
0.8
2.8
0.9
APNK
14.0
5.4
5.5
7.6
6.1
7.1
10.1
6.9
7.4
4.7
10.4
5.8
6.3
15.7
5.5
192
-------
Table B-7. Characteristic Pressure Drop (in mm water) For
Mechanical Regeneration (dust: unsep. coal,
q = 60 m3/m2/hr, C = 10 g/m3).
Kind Of
Fabric
Style 960
Sytle 862B
Style C866B
Style C868B
Style 86 5B
Style C890B
Style C892B
Style 852
Style 853
Style 190
Style 850
Style 802B
Style Q53-875
Style Q53-870
Style Q53-878
APRM1
14.7
5.4
5.7
7.7
7.7
7.1
10.3
7.4
7.9
5.2
11.7
6.2
8.7
19.8
6.8
APRM2
14.7
5.2
5.4
7.9
7.4
8.4
10.7
7-6
7.7
5.2
12.6
6.3
8.4
21.2
7.1
APRM3
14.7
5.1
5.1
7.9
7.1
8.7
10.7
7.4
7.7
5.2
13.3
6.2
8.1
22.3
7.1
193
-------
Table B-8.
Characteristic Pressure Drop (in mm water) For
Reverse Air Flow Regeneration (dust: unsep. coal,
q = 80 m3/m2/hr, Cn = 10 g/m3).
g
0
Kind Of
Fabric
Style 960
Sytle 862B
Style C866B
Style C868B
Style 865B
Style C890B
Style C892B
Style 852
Style 853
Style 190
Style 850
Style 802B
Style Q53-875
Style Q53-870
Style Q53-878
APK
38.9
29.5
31.2
29.3
42.1
65.6
53.9
28.3
26.4
20.9
54.4
26.2
51.9
66.7
52.4
APo
5.8
1.1
1.6
1.9
1.7
3.8
4.1
1.7
1.9
2.1
2.7
1.9
0.9
2.9
1.3
APNK
18.1
5.5
6.6
7.2
7.1
12.5
12.5
5.9
7.7
5.1
14.4
7.8
6.8
13.0
5.3
194
-------
Table B-9.
Characteristic Pressure Drop (in mm water) For
Mechanical Regeneration (dust: unsep. coal,
q = 80 m3/m2/hr, r = 10 g/m3).
& u
Kind Of
Fabric
Style 960
Sytle 862B
Style C866B
Style C868B
Style 865B
Style C890B
Style C892B
Style 852
Style 853
Style 190
Style 850
Style 802B
Style Q53-875
Style Q53-870
Style Q53-878
APRM1
19.8
6.2
7.1
7.7
7.0
18.2
15.3
5.8
9.3
6.0
8.1
10.9
16.0
5.2
APRM2
20.2
6.0
7.1
7.3
7.4
19.0
17.1
6.3
9.6
5.7
8.1
10.9
16.0
5.5
APRM3
20.7
5.7
6.8
7.1
7.4
19.6
15.6
6.0
9.8
5.5
8.1
10.1
14.3
5.5
195
-------
APPENDIX C
Glossary of Terms
Because of differences in terms used in the literature about
dust filtration and filtration media and the various parameters or
stages characteristic of filtration processes, we propose a uniform
usage of terms for this area. The proposed terms have physical meanings
in relation to the processes and phenomena occuring during dust filtra-
tion which are quite different from air filtration processes.
FILTRATION. Process of the removal of solid particles from an
an aerosol stream in or on the structure of a porous
medium.
AIR FILTRATION. Filtration process of atmospheric aerosols.
DUST FILTRATION. Filtration process of industrial aerosols.
DUST FILTRATION TYPE I. The initial phase of the complete dust
filtration process when the fabric first begins
operation as a filtration medium. This phase ends
when the pressure drop reaches a predetermined level.
DUST FILTRATION TYPE II. The second phase continues until the
fabric is fully filled with dust. This phase ends
when the structure reaches the state of equilibrium.
DUST FILTRATION TYPE III. This phase occurs when a stable level
of filling of the fabric by dust has been reached and
when the pressure drop returns to a constant level
after regenerations. This is a typical process for
industrial dust collectors.
196
-------
GAS LOADING ON FILTRATION AREA. Mean calculated value of gas,
in cubic meters, passing through square meter
of filtration medium per hour.
PERMEABILITY. Gas loading on the filtration area at a specific
pressure drop.
(USA) 0.5 inch of water
(Poland) 20 mm of water
DUST LOADING OF FILTRATION AREA. Mean calculated value of dust
quantity, in grams, removed per square meter of
filtration medium.
FILTRATION VELOCITY. The true velocity of the aerosol, in meters
per second, passing through filter medium (measured in
true conditions).
FILLED STRUCTURE. The structure filled with dust, accumulated during
2
filtration process, in g/m , which is retained after
regeneration (without dust cake).
DEGREE OF FILLING. The ratio of a limited filling for a given
regeneration schedule to the completely filled structure,
in percent.
2
DUST-COVERED STRUCTURE. The structure with dust cake in g/m .
The full glossary of terms will be enclosed in final report.
197
-------
APPENDIX D
LIST OF NOMENCLATURE
E = efficiency
G = weight of dust collected on the fabric
z
G = weight of dust collected on the control filter or
weight of dust in cleaned gas
G = weight of dust fed to the testing chamber
AP = static pressure drop
AP = static pressure drop of pure fabric
AP = static pressure drop of filled fabric
AP = static pressure drop of filled fabric at balance
NK.
AP = static pressure of covered fabric
K.
AP = limiting value of pressure drop of ducts/canals formation
JS.K
AP = static pressure drop of dust cake
q = gas loading on filtration area
o
FA = free area
1 = length
n = number of threads in warp in 10 cm
n = number of threads in fill in 10 cm
w
d = diameter of warp yarns
d = diameter of fill yarns
w J
Nm = metrical number of warp yarn
Nm = metrical number of fill yarn
w J
C = characteristic constant
1 = distance between axes of yarns along fill
198
-------
1 = distance between axes of yarns along warp
w
L = fabric filling for a given regeneration cycle
L = dust loading of filtration area
t = time
S = susceptibility for regeneration of fabric
R
S = susceptibility for reverse air flow regeneration
RR
S = susceptibility for mechanical regeneration of fabric
C = initial concentration
199
-------
To Convert From
ft
ft2
ft3
ft/min
ft3/min
in.
. 2
in.
APPENDIX E
METRIC CONVERSIONS
To
meters
2
meters
meters
centimeters/sec
3
centimeters /sec
centimeters
2
centimeters
Multiply By
0.305
0.0929
0.0283
0.508
471.9
2.^4
6.45
200
-------
TECHNICAL REPORT DATA
(Please read Iiiitructions on the reverse before completing)
REPORT NO
EPA-600/7-78-056
2.
3. RECIPIENT'S ACCESSION-NO.
'ITLE ANDSUBTITLE
Tests of Fabric Filtration Materials
5. REPORT DATE
March 1978
6. PERFORMING ORGANIZATION CODE
. AUTHOR(S)
Jan R. Koscianowski.
Maria Szablewicz
Lidia Koscianowska, and
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Institute of Industry of Cement Building Materials
(IPWMB)
45-641 Opole
Oswiecimska Str. 21 POLAND
10. PROGRAM ELEMENT NO.
EHE624; ROAP 21ADJ-094
11. CONTRACT/GRANT NO.
PL-480 (Project P-5-533-4)
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND F
Final; 6/73-12/77
14. SPONSORING AGENCY CODE
EPA/600/13
15. SUPPLEMENTARY NOTES JERL-RTP project officer is James H. Turner, Mail Drop 61,
919/541-2925.
16. ABSTRACT
The report describes laboratory and pilot scale testing of filter fabrics.
Tests were made on flat specimens and on bags. Fifteen styles of fabrics (made from
cotton, polyester, aramid, or glass) were tested, using cement, coal, or talc dusts.
Collection efficiencies and pressure drop data are presented for inlet dust concentra-
tions of 10-11 g/cu m, filtration velocities of 60 and 80 cu m/sq m-hr, temperatures
of 20-30 C, and relative humidities of 55-60%. Conclusions reached were: (1)
fabrics which performed well on bench scale apparatus also performed well on
large scale apparatus; (2) free area calculations for characterizing fabrics are
useful for staple fiber fabrics, but not for continuous filament fabrics; (3) smooth
fiber fabrics with low coefficients of friction may have poor collection efficiency at
high filtration velocities; and (4) cleaning properties of fabrics depend on the fabric
composition and structure, and on dust properties, but not on filtration velocity.
Collateral tests are described.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
COSATI Field/Group
Air Pollution
Dust Filters
Tests
Fabrics
Cotton Fabrics
Polyester Fibers
Glass Fibers
Air Pollution Control
Stationary Sources
Fabric Filters
Aramid
13B
13K
14B
11E
11B
13. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (This Report)
Unclassified
215
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
201
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