EPA-650/2-75-058-a
July 1975 Environmental Protection Technology Series
JOHNS-MANVILLE
CHEAF EVALUATION
U.S.
Off
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EPA-650/2-75-058-Q
JOHNS-MANVILLE
CHEAF EVALUATION
by
Seymour Calvert, Joel Rowan, and Charles Lake
Air Pollution Technology, Inc.
4901 Morena Boulevard, Suite 402
San Diego, California 92117
Contract No. 68-02-1496
ROAP No. 21ADL-004
Program Element No. 1AB012
EPA Project Officer: Dale L. Harmon
Control Systems Laboratory
National Environmental Research Center
Research Triangle Park, North Carolina 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
WASHINGTON, D. C. 20460
July 1975
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EPA REVIEW NOTICE
This report has been reviewed by the National Environmental Research
Center - Research Triangle Park, Office of Research and Development.
EPA, and approved for publication. Approval does not signify that the
contents necessarily reflect the views and policies of the Environmental
Protection Agency, nor does mention of trade names or commercial
products constitute endorsement or recommendation for use.
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environ-
mental Protection Agency, have been grouped into series. These broad
categories were established to facilitate further development and applica-
tion of environmental technology. Elimination of traditional grouping was
consciously planned to foster technology transfer and maximum interface
in related fields. These series are:
1. ENVIRONMENTAL HEALTH EFFECTS RESEARCH
2. ENVIRONMENTAL PROTECTION TECHNOLOGY
3. ECOLOGICAL RESEARCH
4. ENVIRONMENTAL MONITORING
5. SOCIOECONOMIC ENVIRONMENTAL STUDIES
6. SCIENTIFIC AND TECHNICAL ASSESSMENT REPORTS
9. MISCELLANEOUS
This report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series debcribcs research performed to
develop and demonstrate instrumentation, equipment and methodology
to repair or prevent environmental degradation from point and non-
point sources of pollution. This work provides the new or improved
technology required for the control and treatment of pollution sources
to meet environmental quality standards.
This document is available to the public for sale through the National
Technical Information Service, Springfield, Virginia 22161.
Publication No. EPA-650/2-75-058-a
11
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TABLE OF CONTENTS
Page
Abstract
List of Figures iv
List of Tables
Sections
Introduction 1
Source and Control System 3
Test Method 5
Operating Conditions 13
Particle Data 15
Particle Penetration 23
Opacity 27
Economics 29
Manufacturer's Description of Device 31
Operational Problems 33
Conclusions 35
Appendix A 37
Appendix B 45
111
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LIST OF FIGURES
No. Page
1 Schematic Drawing of CHEAP System 4
2 Modified E.P.A. Sampling Train with Heated
Precutter and Cascade Impactor 6
3 Modified E.P.A. Sampling Train with Precutter
and Heated Cascade Impactor with Attached
Final Filter 10
4 Modified E.P.A. Sampling Train with Precutter,
Cascade Impactor, and Heated Final Filter . . .11
5 Inlet Size Distributions 16
6 Inlet and Outlet Size Distributions 17
7 Run 18 Wet and Dry Size Distributions 20
8 Run 19 Wet and Dry Size Distributions 21
9 Theoretical Power and Pressure Drop Vs. Aero-
dynamic Cut Diameter 30
B-l Cumulative Inlet Mass Concentration for
Run #10 47
B-2 Cumulative Outlet Mass Concentration for
Run #10 47
B-3 Cumulative Inlet Mass Concentration for
Run #11 48
B-4 Cumulative Outlet Mass Concentration for
Run #11 48
B-5 Cumulative Inlet Mass Concentration for
Run #12 49
B-6 Cumulative Outlet Mass Concentration for
Run #12 49
IV
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No. Page
B-7 Penetration Versus Dry Particle Diameter for
Run #10 50
B-8 Penetration Versus Dry Particle Diameter for
Run #11 51
B-9 Penetration Versus Dry Particle Diameter for
Run #12 52
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LIST OF TABLES
No.
A-l Inlet and Outlet Total Particulate Loading
for Runs 4 and 5 39
A-2 Inlet and Outlet Sample Particle Data for
Run #6 39
A-3 Inlet and Outlet Sample Particle Data for
Run #7 40
A-4 Inlet and Outlet Sample Particle Data for
Run #8 40
A-5 Inlet and Outlet Sample Particle Data for
Run #9 40
A-6 Inlet and Outlet Sample Particle Data for
Run #10 41
A-7 Inlet and Outlet Sample Particle Data for
Run #11 42
A-8 Inlet and Outlet Sample Particle Data for
Run #12 42
A-9 Inlet and Outlet Total Particulate Loading
for Runs #13 and #14 Using E.P.A. Method 5. . . 43
A-10 Dry and Wet Sample Particle Data for Run #17. . 43
A-ll Dry and Wet Sample Particle Data for Run #18. . 44
A-12 Dry and Wet Sample Particle Data for Run #19. . 44
VI
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ABSTRACT
Fine particulate collection efficiency as a function
of dry particle size has been computed from data taken on
Johns-Manville's CHEAP system. The CHEAP controls emissions
from a diatomaceous earth calcining and drying process
with an overall collection efficiency of 95%. The unit
was operating at a capacity of 710 Am3/min (25,000 ACFM),
at 63°C (145°F), with a pressure drop of approximately
50 to 53 cm water column (19.5 to 21 inches W.C.).
Initial test results showed inlet and outlet size dis-
tributions to be identical with a mass mean diameter of
0.82 ymA and a geometric standard deviation of 3.9. The
data analysis indicates that particle penetration is rela-
tively independent of particle diameter. Further testing
revealed that particle growth occurs prior to the CHEAP
system. Simultaneous heated and unheated impactor runs
provided dried particle size distribution and actual (or
wet) size distribution existing inside the scrubber, re-
spectively. Particle growth was then determined and showed
that particles grew as much as three times their original
size in the submicron range and less for larger sizes.
This particle growth to a more uniform size can explain
why penetration is relatively independent of inlet dry
particle size.
vn
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INTRODUCTION
Air Pollution Technology, Inc. (A.P.T.), in accord-
ance with E.P.A. Contract No. 68-02-1496, "Experimental
Tests of Novel Fine Particulate Collection Devices", con-
ducted a performance evaluation on Johns-Manville's Clean-
able High Efficiency Air Filtration System (CHEAP) .
From November 5 through November 15, 1974, the A.P.T.
sampling team performed simultaneous inlet and outlet
particle sampling measurements on the CHEAP system. After
the data were analyzed, further testing was scheduled to
determine whether particle growth was occurring prior to
the CHEAP system. Therefore, on March 17 through March 21,
1975, the sampling team returned to the test site. Simul-
taneous heated and unheated cascade impactor tests were
performed on the upstream side of the CHEAP to determine
whether particle growth occurred due to a condensation
nuclei effect.
The results of these series of tests on Johns-Manville's
CHEAP are presented in the text.
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SOURCE AND CONTROL SYSTEM
The CHEAP system is primarily a rotary air filter
system which consists of:
1. Water sprays to wet and clean filter medium
2. Rotary drum containing filter medium
3. Water bath reservoir for cleaning the rotary
filter
4. Dual induced blowers used to exhaust the gas to
the stack.
Figure 1 is a schematic drawing of this system. Prior
to the CHEAP, there is a cyclonic precleaner with water
sprays which performs the primary function of removing the
majority of large particles in the inlet stream.
The scrubber is installed to control the emissions
from a diatomaceous earth calcining and drying process.
Emissions enter the precleaner, saturated at a temperature
of approximately 75°C, where they are acted upon by water
sprays and centrifugal forces which collect the large
particles in the stream. The gas exiting the precleaner,
saturated at 63°C, then enters the CHEAP. Water sprays
again contact the gas as it is drawn through the rotating
filter drum where the final cleansing action takes place.
The gas then leaves through the end of the drum while
the particles collected on the filter media are washed as
the drum rotates into the water bath reservoir. With the
help of two blowers, the gas is forced up the stack and
flows into the atmosphere as a saturated plume at approxi-
mately 60°C. The particle laden water in the reservoir is
periodically drained into the plant's main water purifica-
tion system and then refilled.
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OUTLET SAMPLE
PORTS
o
INLET SAMPLE PORTS
STACK
DUAL BLOWER
UNIT
WATER
SPRAYS
ROTATING
FILTER
DRUM
WATER
LEVEL
s
J>
t
y^—
DRAIN
STRAIGHTEN ING
VANES
SAMPLE PORT FOR
PARTICLE GROUTII
ThSTS
TO ROTOCLONE
CYCLONIC
PRECLEANER
DIATOMACFOUS
l.ARTII CALCI \I.\G
AND DRYING PROCESS
CHEAP UNIT
Figure 1 - Schematic drawing of CHEAP system
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TEST METHOD
The performance characteristic of the CHEAP was
determined by measuring the particle size distribution
and mass loading of the inlet and outlet gas sample simul-
taneously.
For the first series of tests performed in November,
1974, a modified E.P.A. type sampling train with a heated
in-stack University of Washington Mark III (U.W.) cascade
impactor was used for particle measurements. Figure 2
shows a schematic drawing of this sample train. In-stack
filter samples were also taken to obtain total particulate
loading and overall efficiency of the system. Due to
saturated inlet and outlet streams, an in-stack impaction
precutter was attached prior to the cascade impactors and
filters in order to prevent water plugging and particle
runoff through the impactor stages. Greased aluminum
substrates were used in the impactor to prevent particle
bounce and minimize wall losses.
An E.P.A. Method 5 Test was also performed to obtain
an unbiased sample of the total particulate loading
throughout the duct and to determine overall efficiency
of the system. Diffusion battery measurements of very
fine particulates were attempted, but the apparatus could
not cope with the excessive moisture content of the gas.
Gas flow rates were determined by means of a cali-
brated type "S" pitot tube along with the necessary temp-
erature and pressure measurements. Due to complex duct-
work, straightening vanes were inserted upstream of the
inlet sample ports in order to cause a uniform flow pattern,
The inlet sample port was located between the precleaner
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I.LAFIN3 JACK1-T
TIIFRMOMETER
I
IMPINGER TRAIN'
IMPACTION C-\SCADr
PRrCUTITR IMPACTOR
STACK
V.ALL
L LIT. RATH I
TIICRMOMT.TER
lOTOMETtR
ORIFICE METER CRY GAS MiiTER
VACUUM
PUMP
Figure 2 - Modified E.P.A. sampling train with heated precuttcr and
cascade inpactor
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and the CHEAP unit. The outlet sample port was located
on the main stack downstream of the fans. Velocity tra-
verses of the inlet and outlet were performed according
to the E.P.A. standards and average velocity points sel-
ected for one point sampling. Sample flow rates were
measured with the usual E.P.A. train instruments so as
to obtain isokinetic sampling. Continuous velocity
head and temperature readings were taken during sampling
in order to detect any changes in the overall system.
CONDITIONS FOR RUNS
A total of 14 simultaneous inlet and outlet sampling
runs were conducted during the first series of tests on
the CHEAP system. One-point sampling was employed for
all runs except Runs 13 and 14, which were E.P.A. Method
5 Tests. The first five tests were in-stack filter sample
runs to determine total particulate loading and overall
penetration. Runs 1, 2, and 3 were allowed to heat up
to stack temperature before the samples were taken.
However, due to heavy water entrainment, even after the
precutter, the filters became plugged, causing high pres-
sure drops in the sampling system. These runs were dis-
carded due to the short sample time incurred by the plug-
ging.
In Runs 4 and 5, the precutters and filters were
wrapped in electrical heating tape and preheated for
approximately thirty minutes before sampling. The temp-
erature was controlled by means of a variac on the heating
circuit. The moisture problem was then solved and repre-
sentative samples were obtained for these runs.
Runs 6 through 12 were heated in-stack impactor runs.
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The precutter and impactor were preheated for a period
of thirty minutes before sampling.
In Run 6 the outlet impactor collected large amounts
of moisture, causing particle runoff through the impactor
stages. Therefore test data for the outlet of Run 6 were
discarded. The heating temperature was increased to
combat this problem.
During Run 7 problems developed in the outlet sample
train, which made it necessary to abort the test. No
problems occurred on the inlet side.
Run 8 ran smoothly, however, it was discovered that
a plant change occurred earlier than scheduled. The plant
process changed from an oil fired furnace for drying to
a gas fired furnace. The outlet sample was affected by
the plant change, whereas the inlet sample was finished
prior to the change.
Run 9 was taken in a high velocity region to deter-
mine if uniform size distribution existed throughout the
inlet and outlet ducts. Large amounts of moisture were
found in the outlet impactor. It was decided that the
water in the impactor was a direct result of the increased
sample flow rate, i.e. increased entrainment of water due
to higher jet impaction velocities in the precutter.
Previous positions of average flow were taken for the
remaining tests.
Runs 10, 11, and 12 were run under identical plant
conditions with no moisture problems encountered.
Runs 13 and 14 were E.P.A. Method 5 Tests. Due to
high grain loading and a saturated stream at the inlet,
sample time at each traverse point was shortened. Results
of the Method 5 confirmed the validity of one point sam-
pling for the performance testing of the CHEAP.
8
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PARTICLE GROWTH
Further testing was performed from March 17 through
March 21, 1975 to determine if particle growth occurred
in the cyclonic precleaner prior to the CHEAP. The CHEAP
was inoperable at the time of testing and therefore was
bypassed. Testing was done after the cyclonic precleaner
and prior to a rotoclone (See schematic of CHEAP system).
In the determination of the extent of particle growth,
two identical U.W. cascade impactors were used side by
side to sample the effluent. Both impactors were preceded
by identical impaction precutters to prevent moisture
entrainment. The final filters of both impactors were
removed and located in separate filter holders following
the impactor. Then, to sample the dry particle size, one
impactor and its final filter were heated in order to
drive off any condensate on the particle. The actual (or
wet) particle size was measured by the unheated impactor
with only its final filter heated to prevent moisture
build-up. The same modified E.P.A. sampling trains were
used for the particle growth tests. Figures 3 and 4 show
schematics of the dry particle size and wet particle size
sampling trains, respectively.
The dry particle size sampling was comparable to the
first series of tests done on the CHEAP in which both
inlet and outlet impactors were heated.
Sampling flow rates again were measured with the
usual E.P.A. train instruments to obtain isokinetic sam-
pling. The inlets of both nozzles were set at nearly
the same position to assure identical aerosol conditions
and the sample flow rates through both impactors were
identical.
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HEATING JACKET .-THERMOMETER
\t
IMPACTIOX CASCADE
IMPINGER TRAIN
PRECUTTER IMPACTOR FINAL
STACK
WALL
ORIPICE
METER
|
THER?v!OMF.TFR
ROTOMETER
VACUUM
GAUGE
DRY GAS
METER
VACUUM
PUMP
SILICA
GF.L
DUY'.R
I:igurc 3 - Mouii'ied I-.P.A. sampling train with precuttcr ami hoatcd
cascade ir.pactor with attached final filter
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THERMOMETER
IMPINGER TRAIN
IMPACTION
PRECUTTER
CASCADE
IMPACTOR FINAL
FILTER
STACK
WALL
ORIFICE
METER
| I.CE JJATH |
THERMOMETER
ROTOMETER
DRY GAS
METER
VACUUM
PUMP
SILICA
GEL
DRYER
Figure 4 - Modified E.P.A. sampling train with precutter, cascade impactor,
and heated final filter
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Five test runs (Rims 15 through 19) were performed
for particle growth determination. Large amounts of
moisture were accumulated in Runs 15 and 16 on the ini-
tial stages of the impactors which caused stage flooding
and particle run off. After an investigation of the
inside of the duct, it was discovered that the sample
nozzles were directly downstream of a central water spray
nozzle. The spray nozzle was turned off and Runs 17, 18,
and 19 were taken. Both impactors on Run 17 were loaded
heavily, which resulted in plugging several jet holes on
the lower stages. Although visual inspection revealed
similar loading characteristics, as in Runs 18 and 19,
the data were considered invalid due to the jet hole
plugging. Sample times for Runs 18 and 19 were decreased
and ideal loadings were obtained. Results of all test
runs are presented in the Particle Data Section of this
report.
12
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OPERATING CONDITIONS
The CHEAP operating conditions during the initial
test period were as follows:
1. Gas flow rates and related parameters as shown
in tabulation below:
DUCT
Temperature
Velocity
Am3 /rain
ACFM
DN m3/min @0°C
DCFM @70°F
Vol. %H20 vapor
Pressure
INLET
63°C
12.2 m/sec
710
25,000
480
18,300
17
-7.6 cm W.C.
OUTLET
60°C
5.8 m/sec
Same as inlet
Same as inlet
Same as inlet
Same as inlet
17
0.2 cm W.C.
2. Water flow rate to the CHEAP system was reported
as approximately 0.053 m3/min (14 GPM) .
3. Pressure drop through the CHEAP system was
approxmiately 48-53 cm W.C. (19-21 inches W.C.)
during the test period.
4. The L/G ratio during the test period was
approximately 0.11 £/m3.
13
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PARTICLE DATA
Four separate sets of data were obtained from the
CHEAP system during the first test period. The first
two data sets (Runs 4 and 5 and Runs 6, 7, and 8) were
obtained at identical one-point sampling locations and
identical plant conditions. The third set of data points
(Runs 9 through 12] was obtained at the previous sample
locations but the plant was switched from an oil-fired
to a gas-fired drying process. Finally, the fourth data
set was obtained from two E.P.A. Method 5 Tests (Runs
13 and 14).
All particle data for Runs 4 through 14 are given in
Appendix A. Particle concentration and sample flow rates
for Runs 4 and 5 are given in Table A-l. Particle concen-
tration and size for Runs 6, 7, and 8 are tabulated in
Tables A-2 through A-4. Size distribution for these runs
is shown in Figure 5. Runs 9 through 12 are represented
in Tables A-5 through A-8, while the size distribution
plots for these runs are illustrated in Figure 6. Finally,
the particle concentrations for the last data set, Runs 13
and 14 (Method 5) are presented in Table A-9.
In this report, the symbol "d " refers to aerodynamic
diameter, which is equal to the particle diameter (d )
in microns (ym) times the square root of the particle
density (p ) in grams per cubic centimeter (g/cm3) times
the square root of the Cunningham slip correction factor
(C1). The symbol "pmA" represents the units of aerodynamic
size,
dpa= dp( Pp0')"2' ^ CD
15
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10,0
O RUN #6
A RUN #7
RUN #8
0.1
20 40 60 80 90
MASS PERCENT UNDERSIZE
98
Figure 5 - Inlet size distributions
16
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10.0
5.0
I
cd
0.5
0.4
0.3
0.2
0.1
Inlet Run # Outlet
10
20 40 60 80
MASS PERCENT UNDERSIZE
Figure 6 Inlet and outlet size distributions
17
90
98
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As seen in Figures 2 and 3, the following aerodynamic
mass median diameters and standard deviations were found:
RUN NO.
6, 7, 8
9, 10, 11, 12
INLET
dpg,ymA
0.82
0.82
"g
4.2
3.9
OUTLET
dpg,pmA
0.82
ag
3.9
Average sample times for the inlet were five to ten
minutes depending on the grain loading while the outlet
sample time averaged approximately forty-five minutes.
Isokinetic sampling was undertaken for all the test
runs, however, isokinetic conditions are not that crucial
for sampling fine particles. For example, the error
caused by sampling 4 ymA particles at a velocity 501
higher or lower than the gas stream velocity would only
be about 2 or 31 of the concentration.
Single point sampling is also generally sufficient
when measuring fine particle size and concentration. The
fine particles will be well distributed in the gas stream,
except in cases where streams with different particle con-
centrations have not had sufficient time to mix. To
illustrate that one point sampling is sufficient for fine
particles, we may note that Stokes stopping distance of
a 3 pmA particle with an initial velocity of 15 m/sec
(50 ft/sec) is about 0.04 cm (0.016 inches) and for a
1 ymA diameter particle is one ninth of that. Since the
stopping distance is the maximum that a particle can be
18
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displaced from a gas streamline by going around a right
angle bend, it becomes apparent that fine particle dis-
tribution in the gas stream will be negligibly affected
by flow direction changes.
Particle data for the particle growth tests are given
in Appendix A also. Particle concentration and size for
Runs 17, 18, and 19 are given in Tables A-10 through A-12.
Size distributions for Runs 18 and 19 are given in Figures
7 and 8, in which the particle size Cwet or dry) is plot-
ted against the cumulative mass percentage of dry solids.
The amount of particle growth is then related to the dif-
ference between the two curves at each mass percent solids.
These figures show that the small particles grow proportion
ately more than the large ones; as would be the case if
the particles acted as condensation nuclei with a small
fraction of soluble material in a super-saturated gas.
The aerodynamic mass mean diameter of the dry particle
size is almost doubled after particle growth occurs. Aero-
dynamic mass median diameters and standard deviations for
Runs 18 and 19 are given below:
RUN NO.
18
19
DRY PARTICLE SIZE
V pmA
1.4
1.1
°g
3.2
3.1
WET PARTICLE SIZE
dpg,vjmA
2.2
2.1
°g
2.3
2.0
The impaction precutters used during the particle
growth tests had cut diameters of approximately 7 microns
aerodynamic. This explains the effect the precutters
19
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Run 18 Wet Size
Run 18 Dry Size
.1
5 10 20 50
SOLIDS MASS PERCENT UNDERSIZE
Figure 7 - Run 18 wet and dry size distributions
90
20
-------
19 Wet Size
19 Dry Size
5 10 20 50 80
SOLIDS MASS PERCENT UNDERSIZE
Figure 8 - Run 19 wet and dry size distributions
90
21
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have on the size distribution curves. If the precutters
had not been used, more particles and therefore more weight
would have been collected on the first three stages of
the U.W. impactor. This would tend to shift the upper
data points downward and in line with the straight line
curves drawn. See Tables A-ll and A-12 for data on
particles larger than 10 ymA diameter.
22
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PARTICLE PENETRATION
Cumulative mass concentration versus aerodynamic
particle diameter was plotted for Runs 10, 11, and 12
and placed in Appendix B. From the analysis of these
curves (Figures B-l through B-6), and noting that the inlet
and outlet size distributions are identical, we can con-
clude that particle penetration is relatively independent
of particle diameter. The penetration is approximately
5% throughout the size distribution.
Particle penetration versus dry particle size for
Runs 10, 11, and 12 are plotted in Figures B-7 through B-9.
The penetration curves are flat and show a relatively
constant penetration over the particle size.
Particle growth appears to have a beneficial effect
on particle penetration, especially in the submicron range.
Particles in this range grow up to as much as three times
their original diameter. They, in turn, are more easily
captured by inertial impaction and thus a lower particle
penetration occurs. Instead of particle penetration in-
creasing for submicron particles, it remains constant due
to the particle growth and thus the penetration curves
appear flat.
It is important to characterize the CHEAP performance
in such a way that it can be compared to other devices or
evaluated for possible use for the collection of particles
which do not grow. In order to do this, the penetration
data obtained for dried particles were treated in the fol-
lowing way:
1. Determine the wet particle diameter to which a dry
particle would grow by means of Figures 7 and 8.
23
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2. For a typical scrubber, find the cut diameter
which would be consistent with the penetration
versus particle diameter data obtained experimen-
tally and converted to "wet" size by step 1 above
The cut diameter for an equivalent scrubber is
computed by means of equation (2), which is
appropriate for the inertial impaction collection
regieme.
Pt = exp [-Ad2pa]
(2)
3. Compute the scrubber "equivalent" cut diameter
corresponding to a given penetration for a dried
particle size by means of the relationships
found in steps 1 and 2.
The results of the procedure described above are
as shown in the tabulation below:
Dried dpa,
ymA
0.5
0.7
1.0
2.0
Pt.*
0.065
0.05
0.046
0.045
Wet dpa,**
Vim A
1.2
1.5
1.9
2.9
*••*
d^
V
2.0
2.1
2.1
2.1
Predicted
dpc, wmA
0.6
0.71
0.9
1.4
Notes: *Average penetration for Runs 10, 11 5 12
**Average wet diameter for Runs 18 $ 19
***Computed by equation (2)
24
-------
The predicted cut diameters are not constant so
it is necessary to use some judgement in interpreting
the results of the computation above. As can be seen in
Figures B-7, B-8, and B-9, the "dry" penetrations for the
three runs are in close agreement for dry particle dia-
meters larger than 0.8 ymA. The cut diameter corresponding
to dry particles larger than 0.8 ymA could be as low as
0.7 to 0.9 ymA and an estimate of d = 0.8 ymA seems
reasonably optimistic in view of the poorer performance
for larger particles. Thus, a typical scrubber, such
as a venturi, which had an 0.8 ymA cut diameter would give
about the same performance on wet particles as the CHEAP.
25
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OPACITY
Plume opacity of the CHEAP system averaged 10% during
the test period. The visual observation method was used
for all opacity measurements which were taken by a Johns-
Manville employee who was a certified observer trained in
a California Air Resources Board "Smoke School". According
to the observer, visible measurements were taken on a hill
above the stack approximately fifteen meters away. A
detached plume enabled the observer to read opacity at the
stack.
27
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ECONOMICS
Cost data for the CHEAP were not provided by the
manufacturer. According to the manufacturer, technology
is not yet sufficiently well established that reliable
capital and operating costs can be presented.
The CHEAP system uses inertial impaction mechanisms
for collection of particles. Figure 9 represents a plot
of pressure drop (cm W.C.) and theoretical power (KW/Mm3/min)
versus aerodynamic cut diameter. The CHEAP system with a
pressure drop of 50 cm W.C. and a cut diameter of about 0.8
umA can Be compared to different scrubber systems using
Figure 9. "F" is froth density for the plates, "f" is
an empirical constant which is influenced by particle
wettability and other factors for Venturis,'^11 equals
the sieve plate hole diameter, and "d " is the packing
diameter.
29
-------
3.0
< 2.0
3.
UJ
u
u
I—I
2
Q
§
W
0.1
THEORETICAL POWER, KW/Mm3/min
10 50 100
500
NO,
la
Ib
2a
2b
3
4
SCRUBBER
Sieve, F=0.4, d,=0.5 cm
Sieve, F=0.4, d"=0.3 cm
Venturi, f=0.25 (non-wettable)
Venturi, f=0.5 (wettable)
Impingement Plate
Packed Column, d =2.5 cm
10 20 50 100
PRESSURE DROP, AP, cm W.C.
300
Figure 9 - Theoretical power and pressure drop vs.
aerodynamic cut diameter
30
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MANUFACTURER'S DESCRIPTION OF DEVICE
CHEAP is a patented system for removal of fine parti-
culate matter from air or gas streams. It was developed
through R$D efforts of the Johns-Manville Corporation over
the past three years. The system provides continuous fil-
tration through polymeric foam media at high velocities.
These velocities bring into dominant effect the inertial
impaction mechanisms of particle capture and make feasible
relatively compact designs.
The CHEAP unit tested by A.P.T. was tailored to the
specific needs for control of emissions from the diato-
maceous earth processing plant. In this case the control-
ling regulation is that requiring plume opacity no greater
than 20 percent. It was assumed that reduction of dust
loading of the plume to about 50 mg/Am3 would suffice,
but some safety factor was built into the device. Its
efficiency could readily be increased should an increase
in average dust load from the plant or a change in control
regulations engender the need. While this system was
operating with pressure drops of 50-53 cm W.C. (19.5 to
21 inches W.C.) in the course of the A.P.T. testing pro-
gram, it has since been modified (by simple changes in
filter medium configuration and in face velocity) to
reduce the pressure drop to 43 cm (17 inches).
It should be noted that no mist eliminator was employed
in the unit as tested. Such a device will be installed
in some additional units now under construction. This
should reduce the amount of condensed moisture reaching
the stack and collect that portion of solid paniculate
retained in the collected water drops.
31
-------
The precleaner mentioned in the body of the report
is a low-pressure-drop, wet cyclonic separator which had
been used as one stage of the dust control system employed
before installation of the CHEAP unit. It was deempd
appropriate to leave it in the train as protection against
excessive thermal excursions, which may occur occasionally
in the diatomite-processing line. While performing this
function it does collect some of the coarser particulate
present and, thus, relieves the CHEAP of some of the
dust loading. The CHEAP has been operated with the pre-
cleaner deactivated.
32
-------
OPERATIONAL PROBLEMS
The CHEAP, although a temporary installation, operated
very smoothly during the testing period, however, plant
process shutdowns delayed testing on schedule. The major
problem in this CHEAP installation is operating under a
corrosive atmosphere. Residual chlorides from the dia-
tomaceous earth process and sulfates from the oil-fired
furnace, together with a saturated gas stream, tend to
accelerate corrosion on the internal parts of the CHEAP.
Carbon steel fans in both of the blowers were gradu-
ally eroding, causing an imbalance in the units. This,
in turn, caused considerable vibrational problems and
excessive wear on the motors' main shaft bearings.
33
-------
CONCLUSIONS
According to the test results obtained on the CHEAP
(Cleanable High Efficiency Air Filter) system, particle
penetration is relatively independent of dry particle size.
Penetration is approximately 5% with the mean dry particle
diameter equal to 0.82 ymA. This aerodynamic diameter is
equivalent to an actual size of 0.45 microns (ym) when the
density for diatomaceous earth is assumed to be 2.5 g/cm3.
The CHEAP appears to be a reasonably efficient device
for fine particulate control of saturated emissions from
a diatomaceous earth calcining and drying process. Par-
ticle growth occurring in the precleaner prior to the
CHEAP is beneficial to the fine particle collection effi-
ciency of the system to a certain extent. Particle growth
tests could not be performed on the outlet of the CHEAP
and therefore the extent to which particle growth increases
collection efficiency was predicted but not quantitatively
'onfirmed.
Results from the E.P.A. Method 5 Tests are comparable
to the results obtained in the one-point total mass loading
tests. We can therefore conclude that one-point sampling
of the CHEAP system was sufficient and representative for
the testing performed.
35
-------
APPENDIX A
37
-------
Table A-l. INLET AND OUTLET TOTAL PARTICULATE LOADING
FOR RUNS 4 and 5
RUN
NUMBER
4
5
INLET
(mg/DNm3)
492
372
OUTLET
Og/DNm3 )
22.5
31.3
Pt %
4.6
8.4
SAMPLE VOLUMES
DNm3
IN OUT
0.061 0.57
0.081 0.57
Table A-2. INLET AND OUTLET SAMPLE PARTICLE DATA FOR RUN #6
IMPACTOR
STAGE
NUMBER
Precutter
1
2
3
4
5
6
7
Filter
Sample
Volume
(DNm3)
INLET
M
cum
(mg/DNm3)
401
356
356
356
356
304
214
126
95.4
d
pc
(ymA)
20
8.9
4.0
1.7
0.97
0.54
0.33
-
0 20
OUTLET
M d
cum pc
(mg/DNm3) (ymA)
High Moisture
Entrainment
Causing Particle
Runoff -
Outlet Data
Invalidated
Mcum
V
pmA
= Cumulative mass collected on that stage and
those below
= Cut diameter (aerodynamic) for that stage
= Microns, aerodynamic = d (C' p ) 1/2
39
-------
Table A-3. INLET AND OUTLET SAMPLE PARTICLE DATA FOR RUN #7
IMP ACTOR
STAC.f-.
I\UML-;I:R
Prccuttcr
1
2
3
4
5
6
7
Filter
Sample
Volume
(DNin3)
INLl.T
M
cum
Cmg/DNm3)
569
501
501
501
500
439
329
252
225
d
pc
(pmA)
20
9.0
4.2
1.8
0.98
0.53
0.35
~
0.095
oun i.r
M d
CUIl! pC
(iag/FJMin3) (pmA)
Outlet Sample
Train Malfuntion-
No data obtained
Table A-4. INLET AND OUTLET SAMPLE PARTICLE DATA FOR RUN *8
IMPACTOR
STAGE
NUMBER
Precutter
1
2
3
4
5
6
7
Filter
Sample
Volume
(DKm3)
INLET
Mcum
Cmg/DNm3)
423
355
355
355
355
309
216
148
114
d
pc
CpiiiA)
21
9.1
4.3
1.8
1.0
0.55
0.33
-
0.077
OUTLET
M
cum
Cmg/DNm3)
Change in
V
(pmA)
Plant
Operation-
Outlet Data
Invalidated
40
-------
Table A-5. INLET AND OUTLET SAMPLE PARTICLE DATA FOR RUN #9
1MPACTOR
STAGE
NUMBER
Precutter
1
2
3
. 4
5
6
7
Filter
Sample
Volume
(DNm3)
INLET
Mcum
(mg/DNm3)
303
272
270
268
265
235
154
103
87
V
(ymA)
20
8.5
4.1
1.7
0.95
0.52
0.32
-
0.11
OUTLET
M d
cum pc
(mg/DNm3) (ymA)
Particle Runoff
Due to Moisture
Accumulation-
Outlet Data
Invalidated
Table A-6. INLET AND OUTLET SAMPLE PARTICLE DATA FOR RUN #10
IMPACTOR
STAGE
NUMBER
Precutter
1
2
3
4
5
6
7
Filter
Sample
Vo lume
(DNm3)
INLET
Mcum
(mg/DNm3)
320
298
298
298
298
254
178
127
95
d
pc
(ymA)
21
9.1
4.3
1.8
1.0
0.55
0.33
~
0.082
OUTLET
"cum
(mg/DNm3)
21.1
17.3
17.3
17.2
17.0
14.6
11.9
9.5
6.5
V
(ymA)
23
10
3.8
2.0
1.1
0.62
0.39
-
0.61
41
-------
Table A-7. INLET AND OUTLET SAMPLE PARTICLE DATA FOR RUN #11
1MPACTOR
STAGT.
NUMBER
Precutter
1
2
3
4
5
6
7
Filter
Sample
Volume
(DNm3)
INI.KT
M
cum
(mg/DNm3)
266
225
225
225
224
193
133
91
68
d
pc
frimA)
20
8.8
4.1
1.7
0.96
0.53
0.32
0.12
OUTLKT
M
cum
(mg/DNm3)
15.1
11.3
11.3
11.3
11.3
9.8
7.7
6.3
3.1
d
pc
(umA)
23
10
3.7
1.9
1.1
0.61
P. 35
0.64
Table A-8.INLET AND OUTLET SAMPLE PARTICLE DATA FOR RUN #12
IMPACTOR
STAGE
NUMBER
Precutter
1
2
3
4
5
6
7
Filter
Sample
Volume
(DNm3)
INLET
Mcum
(mg/DNm3)
265
238
238
238
237
203
139
89
66
d
pc
(ymA)
20
8.8
4.1
1.7
0.96
0.53
0.32
0.089
OUTLET
M
cum
(mg/DNm3)
17.6
12.7
12.7
12.7
12.7
11.9
9.9
8.3
6.0
V
(umA)
23.2
10.3
3.8
2.0
1.1
0.62
0.39
0.64
42
-------
Table A-9. INLET AND OUTLET TOTAL PARTICULATE LOADING FOR
RUNS #13 AND #14 USING E.P.A. METHOD 5
RUN
NUMBER
13
14
INLET
(mg/DNm3)
466
389
OUTLET
(mg/DNm3)
20.6
20.8
Pt%
4.4
5.3
SAMPLE VOLUMES
DNm3
IN
0.058
0.053
OUT
0.62
0.64
Table A-10. DRY AND WET SAMPLE PARTICLE DATA FOR RUN #17
IMPACTOR
STAGE
NUMBER
Precutter
1
2
3
4
5
6
7
Filter
Sample
Volume
(DNm3)
DRY PARTICLE SIZE
cum
(mg/DNm3)
686
660
660
660
634
554
449
317
290
d
pc
(vmA)
•
26.7
11.8
4.5
2.3
1.4
0.72
0.42
0.09
WET PARTICLE SIZE
M
cum
(mg/DNm3)
475
475
449
449
449
343
71.3
31.7
5.3
V
(ymA)
26.3
11.5
4.3
2.2
1,3
0.70
0.39
0.14
43
-------
Table A-ll. JRY AND WtT SAMPLE PARTICLE DATA FOR RUN' #18
IMP ACTOR
STACK
NUMHHR
Prccutter
1
2
3
4
5
6
7
Filter
Sample
Volume
(DNm3)
DRY
M
cuu
(mg/DNm3)
467
394
369
369
344
320
202
108
64
d
pc
(ymA)
26.3
11.5
4.3
2.2
1 .3
0.70
0.39
0.059
Wl.T
M
cum
(mg/DNm3)
369
569
514
544
295
201
95.9
27.1
d
pc
(ymA)
26.6
1] .7
4.4
2.3
1.3
0.71
0.5Q
0.058
Table A-12. LiRY AND WET SAMPLE PARTICLE DATA FOR RUN
IMl'ACTOR
STACK
NUMBIiR
Precutter
1
2
3
4
5
6
7
Filter
Sample
Volume
(UNm1)
DRY
Mcum
(mg/DNm3)
295
219
219
219
216
204
160
88.6
49.2
d
pc
(ymA)
25.8
11.3
4.3
2.2
1.2
0.69
0.39
0.080
WET
cum
(my/DNm3)
194
194
189
187
170
101
41.8
11.8
V
(ymA)
26.6
11.7
4.4
2.3
1.3
0.71
0.41
0.077
44
-------
APPENDIX B
45
-------
400
1
co
in
1-1
u
300
200
100
0
012345
AERODYNAMIC DIAMETER, ymA
Figure B-l - Cumulative inlet
mass concentration for Run #10
20
15
oo
CO
w
I—I
t-l
J
L
10
012345
AERODYNAMIC DIAMETER, ymA
Figure B-2 - Cumulative outlet
mass concentration for Run #10
-------
00
240
200
*
CO
C/)
w
> 100
0
01234
AERODYNAMIC DIAMETER, umA
Figure B-3 - Cumulative inlet mass
concentration for Run #11
to
H
<
01 34
AERODYNAMIC DIAMETER, ymA
Figure B-4 Cumulative outlet mass
concentration for Run #11
-------
260
01234
AERODYNAMIC DIAMETER, ymA
Figure B-5 - Cumulative inlet mass
concentration for Run #12
e
z:
Q
hH
H
01234
AERODYNAMIC DIAMETER, ymA
Figure B-6 - Cumulative outlet mass
concentration for Run #12
-------
.10
2
o
t-l
H
U
PL,
2
O
2
W
a,
u
i— i
i
01
0.3 0.5 1.0 2.0 3.0
AERODYNAMIC PARTICLE DIAMETER, ymA
Figure B-7 - Penetration versus dry particle diameter
for Run 10
50
-------
o
I—I
H
U
o
l-t
H
H
PJ
W
0<
W
u
HH
£
<
0.3 0.5 1.0 2.0 3.0
AERODYNAMIC PARTICLE DIAMETER, ymA
Figure B-8 - Penetration versus dry particle diameter
for Run 11
51
-------
H
U
PH .05
2
O
W
w
—
.03
.01
iiiiiiii iiiiiiiiii iiiii iiiii iiiii iiiii ••••••••« iniiiiiii iniiin »'""
0.3 0.5 1.0 2.0 3.0
AERODYNAMIC PARTICLE DIAMETER, ymA
Figure B-9 - Penetration versus dry particle diameter
for Run 12
52
-------
TECHNICAL REPORT DATA
(Please read faUfuelions on the reverse before completing)
1 REPORT NO
EPA-650/2-75-058-a
3 RECIPIENT'S ACCESSION NO.
4 TITLE AND SUBTITLE
Johns -Manville CHEAP Evaluation
5 REPORT DATE
July 1975
6. PERFORMING ORGANIZATION CODE
7 AUTHOR(S)
Seymour Calvert, Joel Rowan, and Charles Lake
8 PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORSANIZATION NAME AND ADDRESS
Air Pollution Technology, Inc.
4901 Morena Boulevard, Suite 402
San Diego, CA 92117
10. PROGRAM ELEMENT NO.
1AB012; ROAP 21ADL-004
11. CONTRACT/GRANT NO.
68-02-1496
12 SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research .and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Task Final: 11/74-6/75
14. SPONSORING AGENCY CODE
15 SUPPLEMENTARY NOTES
. ABSTRACT The pepol!t gives resuits of an evaluation of the Johns-Manville CHEAP sys-
tem for controlling particulate emissions. Fine particulate collection efficiency as a
function of dry particle size was computed from data taken on the CHEAP system, a
system used to control emissions from a diatomaceous earth calcining and drying
process with an overall collection efficiency of 95%. The unit was operating at a cap-
acity of 710 A cu m/min (25,000 acfm), at 63C (145F), with a pressure drop of approx-
imately 50-53 cm (19. 5-21 inches) water column. Initial tests showed inlet and outlet
size distributions to be identical with a mass mean diameter of 0. 82 micrometers A
and a geometric standard deviation of 3. 9. The data analysis indicates that particle
penetration is relatively independent of particle diameter. Further tests revealed that
particle growth occurs prior to the CHEAP system. Simultaneous heated and unheated
impactor runs provided dried particle size distribution and actual (or wet) size distr-
ibution existing inside the scrubber, respectively. Particle growth was then determ-
ined, showing that particles grew as much as three times their original size in the
submicron range, and less for larger sizes. This particle growth to a more uniform
size can explain why penetration is relatively independent of inlet dry particle size.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c COSATI Field/Group
Air Pollution
Dust
Diatomaceous Earth
Roasting
Drying
Impactors
Scrubbers
Air Pollution Control
Stationary Sources
Fine Particulate
CHEAP Systems
Collection Efficiency
13B
11G
08G
13 H
07A
18 DISTRIBUTION STATEMENT
Unlimited
19 SECURITY CLASS (This Report)
Unclassified
21
NO OF PAGES
63
20 SECURITY CLASS (Thispage/
Unclassified
22. PRICE
EPA Form 2220-1 19-73)
53
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