AIR-BORNE PARTICULATE EMISSIONS
FROM COTTON GINNING OPERATIONS
waaam



•V.V.V.V

The Robert A. Taft
Sanitary Engineering Center
TECHNICAL REPORT
A60-5
U. S. DEPARTMENT OF HEALTH,
EDUCATION, AND WELFARE

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AIR-BORNE PARTICULATE EMISSIONS
FROM COTTON GINNING OPERATIONS
Prepared by
Engineering Research and Development Unit
Air Pollution Engineering Research
U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service
Bureau of State Services
Division of Engineering Services
Robert A. Taft Sanitary Engineering Center
Cincinnati, Ohio

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INTRODUCTION
Modern cotton ginning installations using
pneumatic conveying equipment, air blast clean-
ing equipment, and seed cotton conditioning
equipment have increased the output of normal
ginning operations and improved cotton fiber
quality. This gain in output has been accom-
panied by a major increase in the volume of air
bearing lint and dust discharged to the atmos-
phere. The increased proportion of machine-
picked cotton supplied to ginning operations
has further increased the volume of waste ma-
terials. Present day ginning practices may
produce up to 1, 000 pounds of waste material
for each bale of cotton ginned, a significant por-
tion of which will be discharged to the atmos-
phere.
Although the discharge of waste material to
the atmosphere from the individual cotton gin-
ning operation generally results in only a local
air pollution problem, the number of such es-
tablishments and the gradual urban encroach-
ment into the areas of ginning operations is
great enough to warrant consideration of suit-
able control methods. Figures 1 and 2 indicate
the pollution effects and the pollutants involved
in the problem. In order to consider possible
solutions to these problems, field and labora-
tory studies of particulate emissions from cot-
ton gins were conducted by the Public Health
Service, in cooperation with the Agricultural
Research Service.

-tLl
•v4
-A1
Figure 1. LOCALIZED POLLUTION
PROBLEM
Figure 2. EXAMPLES OF GIN
DISCHARGES

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2
AIR-BORNE PARTICULATE EMISSIONS FROM COTTON GINNING OPERATIONS
OBJECTIVES
The objectives of these studies were three-
fold: first, to assess the quantity of particulate
emissions from cotton ginning operations in
terms of its air pollution potential; second, to
evaluate the effectiveness of standard laboratory
quality evaluation test equipment for predicting
these emission values; and third, to develop an
economically feasible control technique and
suggest control equipment for the reduction of
particulate emissions to the atmosphere.
From the standpoint of the air pollution po-
tential of cotton ginning particulate emissions,
it is necessary to differentiate portions of the
emissions by particle size. Those which are of
sufficiently small size to carry beyond the prem-
ises of the ginning operations under average
weather conditions constitute a local air pollu-
tion problem. That portion having a large
enough particle size to deposit on the gin prem-
ises is a lesser problem. Based on an average
wind speed of 10 miles per hour and for par-
ticles with a density equal to the average den-
sity of particulate emissions from ginning oper-
ations, it is assumed in this report that parti-
cles 100 microns in diameter and larger will
deposit on the premises and that particles
smaller than 100 microns will carry beyond the
gin premises to the surrounding community.
BACKGROUND
Field sampling of cotton gin effluent and lab-
oratory investigation of procedures for the eval-
uation of air pollution materials discharged to
the atmosphere from the ginning of cotton were
conducted at the Cotton Ginning Laboratory,
Agricultural Research Service, U.S. Depart-
ment of Agriculture, Stoneville, Mississippi.
The investigation was made at this laboratory,
since this operation was considered to be repre-
sentative of ginning operations in general, and
the cotton harvested by both machine-and hand-
picked methods and processed during testing
was representative of the cotton from the areas
in question.
The flow diagram, Figure 3, indicates the
following major sources of particulate emis-
sions: unloading fan, six cylinder cleaner,
stick and bur machine, gin stand, separator
No. 2, seven cylinder cleaner, separator No. 3,
and the condenser. The unloading fan, discharge
point No. 1, supplies the air for the transfer of
cotton from the storage bins or from a wagon to
the first separator. These wastes are carried
to the dust house by the moving air stream and
consist mostly of sand, dirt, and other fine
materials.
The cotton then passes from the first sepa-
rator onto the feed control, into the tower dryer,
through a boll trap, and then to the six cylinder
cleaner which opens and cleans the boll cotton.
The waste discharge from the six cylinder
cleaner, discharge point No. 2, is carried to
the dust house by a moving air stream and con-
sists of fine particles of leaf trash, dirt, sand,
stems, and small sticks. (See Glossary)
From the cleaner the cotton is moved to the
stick and bur machine which removes burs,
sticks and stems, together with fine trash not
removed by the cylinder cleaner. The discharge
duct from the stick and bur machine joins with
the air discharge duct from the gin stand and
wastes from these sources are carried to the
dust house, designated as discharge point No. 3.
Samples were taken from the combined dis-
charges because individual samples from these
two emission sources were unobtainable due to
the inaccessibility of the separate ducts.
From the stick and bur machine the cotton
passes to a second separator, then to a stub
tower dryer, and then to a seven cylinder clean-
er. The discharge from the second separator
at discharge point No. 4 is emitted directly to
the atmosphere outside the building. These
wastes, carried through the separator, con-
sisted mainly of fine particles of leaf trash,

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Field Sampling Equipment and Techniques
3
NO. Z DISCHARGE
TO OUTSiOC pr. «
WAGON
NO. 40 90AR0MAN e&H
SEVEN CYLINDER
'no «SPhElPSFAN
© 1925 RPM
' DISCHARGE TO'
CONDENSER DISCHARGE
'TO DUST MOUSE
DISCHARGE COMBINED
NO. 35 CLARAGE
FIGURE 3. FLOW DIAGRAM OF U. S, DEPARTMENT OF AGRICULTURE
COTTON GIN, STONEVILLE, MISSISSIPPI
The waste discharge from the seven cylinder
cleaner, discharge point No. 5, is carried to
cyclones. Tests include the use of either the
standard or the alternate (parallel) cyclones.
These wastes consist mainly of pin and pepper
trash and dirt.
The seed cotton then passes from the seven
cylinder cleaner on a belt distributor to the
extractor-feeder and then to the huller front
gin stand. The trash from the gin stand, burs,
sticks, stems, motes, and pin and pepper trash
is combined, as previously noted, with the
waste discharge from the stick and bur machine
and blown to the dust house, discharge point
No. 3.
From the gin stand the cotton is transferred
first to a separator which removes fine leaf
particles, motes, dust, and sticks, which are
discharged directly to the atmosphere outside
the building, discharge point No. 6. The cotton
next travels to the lint cleaner and then to the
condenser, which discharges pin and pepper
trash to the dust house, discharge point No. 7,
then to the baler, and out as a finished product.
Field Sampling Equipment and Techniques
Initially it was intended to take simultaneous
samples at each discharge point to differentiate
between total particulate and air pollution par-
ticulate emissions to the atmosphere, i. e.,
particles less than 100 microns in size. Dupli-
cate sampling trains were to be used, with one
train preceded by a settling chamber to remove
the particulate 100 microns or over in diameter.
Due to weather conditions, insufficient cotton
was on hand at the Stoneville Laboratory to
allow sampling by both techniques at every point
of discharge as originally planned. To further
conserve cotton, samples were taken simulta-

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4	AIR-BORNE PARTICULATE EMISSIONS FROM COTTON GINNING OPERATIONS
inary evaluations were made at each discharge
point to determine those locations containing
non-air-pollution particulate, and the settling
chamber, Figure 4, was employed at only those
emission points. The sampling system, Figure
5, consisted of a sampling probe, a high effi-
ciency cyclone used during high loadings only,
a glass-fiber filter, a pump, an orifice flow
meter, an integrating bellows gas meter, and
various wet- and dry-bulb thermometers.
All points of discharge to the atmosphere
were sampled. Whenever possible, sampling
positions were selected along straight runs of
duct at least 12 pipe diameters in length, and
samples were taken at a distance equal to 8
pipe diameters(l) from the start of the run.
Where it was necessary to sample ducts not
having 12 pipe diameters of straight flow, sam-
ples were obtained at a point two-thirds of the
longest straight flow distance downstream from
a point of gas flow disturbance such as a bend,
damper or valve.
Four to sixteen point sampling traverses
were run, when possible, at each sampling
point using isokinetic sampling procedures. (1)
When the settling chamber was used, the probe
was fixed at a point in the duct with a velocity
equal to the average velocity through the duct,
as it was impossible, because of the bulky na-
ture of the equipment, to move the probe for
sampling traverses.
GAS
EXIT
GAS-
INLET
I. SAMPLING PROBE
2.SETTLING CHAMBER
3.	PROBE CONNECTED TO
SAMPLING SYSTEM NO. 2
4.	BLOWER
5.	MOTOR
6.	FLOW VALVE
7.	PITOT TUBE
8.	INCLINED
MANOMETER
FIGURE 4. SETTLING CHAMBER USED IN CONJUNCTION WITH
SAMPLING SYSTEM NO. 2
(1) "Methods for Determination of Velocity, Volume, Dust and Mist Content of Gases", Bulletin

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Emission from Ginning Operations
5
GAS
EXIT
GAS
INLET
8a
8b
1.	SAMPLING PROBE
2.	HIGH EFFICIENCY CYCLONE
3.	FIBER-GLASS FILTER 6 HOLDER
4.	PUMP
5.	PUMP BYPASS VALVE S LINE
6.	DRY BULB THERMOMETER
7. ORIFICE
8a MANOMETER TO REGISTER
8b. AP ACROSS ORIFICE
SURGE BOTTLE
9.	BELLOWS GAS METER
10.	DRY BULB THERMOMETER
I I. WET BULB THERMOMETER
FIGURE 5. SAMPLING SYSTEM NO. 2
Emissions from Ginning Operations
The data on atmospheric emissions, Table 1,
are limited in that replicate samples were ob-
tained during ginning of both hand- and machine-
picked cotton for only the cyclone discharges.
There is, therefore, no indication of the varia-
tions at the other points of discharge due to the
method of picking. Table 2 presents data on
the amount of material collected by the settling
chamber and the sampling train, expressed in
percent by weight of cotton ginned. Table 3
contains calculated particle discharges to the
atmosphere for the total emissions and for the
air pollution portion of the emissions, i. e. ,
that portion of the discharged particulates less
than 100 microns in diameter.
The evaluation of the particulate emission
data from the ginning operation was made, as
previously discussed, on two bases: first, on
a consideration of the total particulate emis-
sion; and, second, on a consideration of only
that portion which constitutes a local air pol-
lution problem, i. e. , particles of less than
100 microns in diameter.
The data in Table 3 show that the calculated
air pollution portion of the total particulate dis-
charge (i.e. , particles less than 100 microns
in diameter) from the gin to the atmosphere
with no air pollution control devices utilized
was approximately 7. 0 pounds per bale (1. 39%)
of cotton ginned. However, the gin had in-
stalled two types of cyclones on the discharge
from the seven cylinder cleaner. One was an
84" diameter standard cyclone with tapered top
and bottom sections and the other a pair of 34"
diameter high efficiency design operating in

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TABLE 1
SUMMARY OF FIELD DATA
U. S. DEPARTMENT OF AGRICULTURE COTTON GINNING LABORATORY
STONEVILLE, MISSISSIPPI
Sample Point
Description
Unloading Fan
Pipe
Size
16" D
Average
Velocity
FPM
4680
Volume
SCFM
6280
Type Cotton,
Picking Method
Machine
Sam
Settling
Chamber
GR/SCF
pies Collected
Sampling
Train
GR/SCF
0. 359
Total
GR/SCF
0. 359
Average
Emission
Rate lbs/hr
19.32
Six Cylinder
Cleaner
16" D
3150
3878
Hand
0. 078
0. 037
0. 115
3.82
Stick & Bur Ma-
chine Discharge
Combined With
Huller Front &
Mote Discharge
from Gin Stand
11" D
4320
2783
Hand
0. 524
0. 026
0. 550
13.12
No. 2 Separator
12" D
4450
3260
Machine
0. 065
0. 065
1.82
Seven Cylinder
Cleaner to
Cyclones
Standard Cyclone
Inlet*
18" D
4340
7030
Hand
Machine
0.0957
0.0957
0.0124
0.0103
0.1081
0.1060
6.51
6.39
Standard Cyclone
Outlet*
19-1/4" D
3890
7030
Hand
Machine
0.0070
0.0150
0.0070
0.0150
0.42
0.90
Alternate Cy-
clone Inlet*
18" D
4180
6731
Hand
Machine
0.0347
0.0346
0.0186
0.0495
0.0533
0.0841
3.08
4.85
Alternate Cy-
clone Outlet*
14" D
3680
6731
Hand
Machine
0.0019
0.0054
0.0019
0.0054
0.11
0.31
Separator No. 3
21" D
1610
3865
Hand
0.0440
0.0440
Condenser
42" D
1240
11523
Hand
0.0223
0.0223
1.46
2.20

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Emissions from Ginning Operations
TABLE 2. EFFLUENT SUMMARY .
(Percent by Weight of Cotton Ginnedf
Sample
Point No.
Sample Point Description
Settling
Chamber (S)
Sampling Train (A)
Total (T)
Unloading Fan
0.966
0.966
Six Cylinder Cleaner
0.130
0.062
0.192
Stick & Bur Machine Dis-
charge Combined With Hul-
ler Front & Mote Discharge
From Gin Stand
0.625
0.031
0.656
Separator No. 2
0.091
0.091
Seven Cylinder Cleaner To
Cyclones
'Buffalo" Cyclone Inlet
0.289
0.034
0.323
'Buffalo" Cyclone Outlet
0.033
0.033
"A.E.C." Cyclone Inlet
0.100
0.097
0.197
"A.E.C." Cyclone Outlet
0.010
0.010
Separator No. 3
0.073
0.073
Condenser
0.106
0.106
TABLE 3. ATMOSPHERIC PARTICLE EMISSIONS
Description of Condition
Fractions Under Conditions*
Totals
% by Weight
of Cotton Ginned
Pounds
per bale
A. Total Discharge,
No Control
T +T +T +T +T +T +T +T
1 2 3 4 5A 5C 6 7
2
2.34%
11.7
B. Total Discharge, Installed
Cyclones in Use
T1+T2+T3+T4+T5B+T5D+T6+T7
2
2.11%
10.5
C. Total Discharge of Air
Pollution Material
(Cyclones not in Use)
A1+WA4+A5A+A5C+VA7
2
1.39%
7.0
D. Total Discharge of Air
Pollution Material
(Cyclones in Use)
A1+A2+A3+a4+A5b+A5d+A6+A7
2
1.35%
6.8

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8
AIR-BORNE PARTICULATE EMISSIONS FROM COTTON GINNING OPERATIONS
efficiencies from 85 to 93% and 95 to 96% respec-
tively, but were applied only to the discharge
from the seven cylinder cleaner, the average
air pollution discharge to the atmosphere, when
these cyclones were being utilized, was 6. 8
pounds per bale (1. 35%) of cotton ginned. The
total particulate discharged to the atmosphere
from the ginning operation, when no control
equipment was used, was approximately 11. 7
pounds per bale (2. 34%) of the cotton processed.
With the cyclones in use for the seven cylinder
cleaner, the total particulate discharge was
10. 5 pounds per bale (2. 11%) of the cotton
ginned. Since the gin sampled was selected as
typical of such operations, these values may be
assumed to show generally the order of dis-
charges from cotton gins.
Laboratory Quality Evaluation Test Equipment
Two standard laboratory quality evaluation
test devices were considered as having potential
application in predicting air pollution particu-
late emissions from the cotton ginning opera-
tion. The first of these was the fractionator,
Figures 6 and 7. This equipment, normally
used to determine the quantity of foreign ma-
terial contained in cotton, consists essentially
of a sheet metal box-like container in which the
cotton is agitated by air jets. In the operation
of this device, a sample of non-ginned cotton is
prepared for fractionation by hand removal of
unopened bolls, seeds, and trash. Weights of
cotton and removed trash are obtained. The
prepared cotton is then placed in the fractiona-
tor and a compressed air supply, connected to
inlets at the bottom rear of the fractionator, is
turned on. The cotton is lifted by the air stream,
follows the curved top of the fractionator, drops
onto the air discharge slots in the bottom front
of the fractionator, and is carried across the
bottom to be once again picked up by the air
jets, repeating the cycle. The agitation of the
cotton by the air stream is continued for a
period of ten minutes.
As the cotton is churned by the air stream,
the foreign material is dislodged and is carried
along with the fractionator effluent. The test
equipment used to determine the waste material
discharged from the fractionator sampled the
entire air flow of the fractionator, and consist-
ed of a settling chamber, a cyclone, and a glass
fiber filter which was followed by a high volume
blower to eliminate excessive back pressure on
the fractionator. After fractionation, the cotton
and the fractions collected by the sampling sys-
tem were weighed to determine the amounts of
foreign material removed from the cotton.
Figure 6. EXTERIOR VIEW	Figure 7. INTERIOR VIEW

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Laboratory Quality Evaluation Test Equipment
9
A second standard laboratory quality evalua-
tion test device used to predict the amount of
air pollution particulate emission from cotton
gin operations was the Shirley Analyzer, Figure
8. Basically, this equipment is used to deter-
mine the amount of foreign material remaining
in the clean lint after ginning. Its principle of
operation is similar to that of a lint cleaner in
that it uses a similar saw arrangement for the
removal of foreign material. It is more effi-
cient than lint cleaners in use commercially,
but causes a greater loss of usable fibers.
As a method for collecting the fine fraction
of the foreign material removed from a cotton
sample by the Shirley Analyzer was not avail-
able, it was necessary to determine this value
by a material balance; that is, the weight of
cotton placed in the analyzer must equal the
weight of the cleaned sample plus the collected
waste material plus the fine fraction quite ap-
propriately designated as noncollected waste.
Table 4 contains fractionator sampling train
data for cotton obtained from the Stoneville,
Mississippi, area. Table 5 contains similar
Figure 8. SHIRLEY ANALYZER
fractionation data on cotton from the Clemson,
South Carolina, area. Data obtained from the
tests performed by the Shirley Analyzer for
cotton from the Stoneville, Mississippi, area
are presented in Table 6.
TABLE 4. FRACTIONATION DATA ON 20 SEED COTTON SAMPLES FROM THE
STONEVILLE, MISSISSIPPI AREA
Sample
Number
Large Foreign Material
Removed by Hand
Before Fractionation
Seed Cotton
After Frac-
tionation
Settling Chamber Catch
Cyclone Catch
Material
Collected
On Filter
Wet
Dry
Wet
Dry

gms
gms
gms
gms
gms
gms
gms
Hand-Picked
1
2
3
4
5
6
7
8
9
10
0.2
0.3
0.4
0.6
0.2
0.8
0.2
0. 5
0. 6
0.8
179. 0
206. 0
176. 0
166.0
170.0
171.0
159.0
171.0
170.0
172. 0
1.	09
.86
2.	00
.77
,85
5.32
4.92
6.88
5.35
5.01
.95
.75
1.86
.70
.75
4.95
4.60
6.45
5.05
4.70
1.19
1.82
1.44
1. 18
1.	39
1.47
1.72
1.11
2.	15
1.43
1.07
1.73
1.36
1. 10
1.30
1.42
1.61
1.06
2.02
1.37
0. 083
0. 096
0. 099
0.055
0. 064
0. 083
0. 091
0. 075
0. 156
0. 088
Machine-Picked
11
12
13
14
15
16
17
18
19
20
5.6
8.1
5.6
4.6
4. 6
9.6
7.7
7. 0
10.3
6.2
169. 0
140.0
172.0
158. 0
154.0
159.0
146.0
168.0
197. 0
150. 0
10.83
6. 00
9. 38
7.74
7.89
9.05
9.61
12.99
13. 59
9.75
10. 00
5.33
8.43
6.97
7. 19
8.23
8.65
11.81
12.34
8.86
.90
1.45
1.85
1.82
1.55
1. 55
1.24
1.43
2.10
1.20
.83
1.32
1.65
1.66
1.43
1.43
1.08
1. 30
1.96
1.10
0. 086
0. 095
0. 130
0. 083
0. 092
0. 252
0. 125
0. 155
0.220

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TABLE 5
FRACTIONATION DATA ON 20 SEED COTTON SAMPLES
FROM THE CLEMSON, SOUTH CAROLINA AREA
Sample
Large Foreign Material
Removed by Hand Before
Fractionation
Seed Cotton After
Settling Chamber Catch
Cyclone Catch
Material
Collected
On Filter
Number
Fractionation
Wet
Dry
Wet
Dry

gms
gms
gms
gms
gms
gms
gms
i
Cd
O
»
%
H
HH
O
ci
f
>
H
W
M
CO
Cfl
ft
O
3
3
o
o
o
-3
H
O
52
a
z
a
o
M
ss
>
H
o
52
w
Hand- Picked
21
22.4
186.0
12.38
11.03
1.81
1.40
0.126
22
17.8
169.0
8.78
8.44
.96
.90
0.113
23
19.1
158.0
12.57
12.25
1.38
1.30
0.149
24
28.9
144.0
11.70
11.25
1.43
1.34
0.150
25
36.1
122.0
10.63
10.22
1.00
.96
0.118
26
30.0
170.0
14.23
13.76
1.21
1.14
0.175
27
29.2
176.0
15.37
15.00
1.34
1.31
0.154
28
35.6
184.0
13.08
12.70
1.15
1.08
0.138
29
18.8
150.0
13.09
12.75
1.39
1.31
0.133
30
26.4
170.0
15.23
14.81
1.00
.94
0.136
Machine-Picked
31
5.0
166.0
4.11
3.78
.95
.86
0.080
32
5.4
153.0
5.64
5.18
.96
.87
0.061
33
2.0
196.0
6.56
6.10
.70
.63
0.063
34
5.9
141.0
5.99
5.43
.91
.82
0.096
35
3.7
159.0
7.74
7.23
.66
.59
0.072
36
10.4
169.0
9.81
9.16
.78
.70
0.062
37
3.2
162.0
6.99
6.43
.89
.81
0.079
38
11.9
156.0
8.80
8.11
.82
.75
0.083
39
13.2
134.0
17.41
16.30
.80
.73
0.068
40
13.9
145.0
15.63
14.59
1.22
1.12

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Laboratory Quality Evaluation Test Equipment
11
TABLE 6
SHIRLEY ANALYZER AND DRYING DATA ON 19 SAMPLES OF
LINT COTTON FROM THE STONEVILLE AREA
Sample
Classi-
fication
Wet Sample
of Lint
Fed
Dried
Sample of
Lint Fed
Wet Samples
Dried Samples
Noncollected
Waste
Cleaned
Lint
Collected
Waste
Cleaned
Lint
Collected
Waste

gms
gms
gms
gms
gms
gms
% by Weight of
Dried Cotton*
Hand-Picked Without Lint Cleaner
1
100.00
92.70
94.40
2.34
89.23
2.13
1.446
2
100.00
93.17
94.53
2.60
89.29
2.37
1.621
3
100.00
92.73
94.82
2.46
90.28
2.14
0.334
4
100.00
94.17
94.88
2.54
90.74
2.25
1.253
5
100.00
92.13
94.42
2.56
89.04
2.31
0.847
Hand-Picked With Lint Cleaner
6
100.00
93.04
96.28
1.32
91.51
1.18
0.376
7
100.00
93.62
96.14
1.28
91.78
1. 14
0.748
8
100.00
92.78
96.64
.87
91.83
.83
0.129
9
100.00
93.24
96.65
1.03
91.38
.97
0.955
Machine-Picked Without Lint Cleaner
10
100.00
94.51
93.76
4.90
88.62
4.29
1.693
11
100.00
94.55
91.73
6.33
86.86
5.53
2.285
12
100.00
94.28
94.67
3.88
89.34
3.45
1.580
13
100.00
94.61
95.00
3.63
89.71
3.21
1.786
14
100.00
94.04
93.14
4.96
88.81
4.31
0.978
Machine-Picked With Lint Cleaner
15
100.00
94.26
94.19
4.27
89.65
3.72
0.944
16
100.00
94.48
93.28
4.91
88,83
4.30
1.429
17
100.00
94.02
94.37
3.92
89.50
3.60
0.979
18
100.00
94.50
94.71
3.26
89.58
2.90
2.138
19
100.00
94.44
94.48
3.68
90.13
3.31
1.059

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12	AIR-BORNE PARTICULATE EMISSIONS FROM COTTON GINNING OPERATIONS
Applicability of Fractionator as Air Pollution Indicator
A statistical evaluation (Appendix 1) of the
fractionator discharge data, Tables 4 and 5,
indicates it is not possible to separate the ef-
fects of the picking method from the effects of
the area from which the cotton was obtained. It
is, therefore, not possible, based on fraction-
ator data, to make a general statement that one
picking method results in less air pollution ma-
terial than the other, independent of the area
from which the cotton was obtained. By a com-
parison of the mean percent air pollution ma-
terial for each picking method and each area
separately, it was observed that the Clemson
area machine-picked cotton yielded significantly
less air pollution material than did hand-
picked cotton from the Clemson area, and both
hand- and machine-picked cotton from the
Stoneville area. The latter three did not differ
significantly from each other.
Based on the fractionator data for cotton
from the Stoneville area, the ranges of expected
amounts of air pollution material from individual
cotton samples during fractionation were es-
timated using statistical techniques. (2) The
limits of the estimated ranges are such that the
probability is less than one in twenty that not
more than 5% of the individual samples will fall
beyond these limits. All data were used in com-
puting these limits, since statistical analysis
failed to detect a difference between the amount
of waste removed by either method of picking
for cotton from the Stoneville area.
A comparison of field data (Table 3) with the
limits of the estimated ranges based on the
fractionator data is as follows:
Air pollution material dis-
charged to the atmosphere
from the ginning operation
(Percent by weight of cot-
ton ginned - Table 3). . . .
Limits of estimated range
of air pollution material
(Percent by weight of cot-
ton ginned after removal
of seeds)	
It is obvious that the field test data fall with-
in the fractionator range of air pollution ma-
terials discharged from the ginning operation;
hence fractionator data may be used to predict
the amount of air pollution material that would
be discharged during the ginning of cotton with-
out control equipment. Further, it is possible
by statistical methods to estimate the discharge
of air pollutant material (expressed as percent
by weight of ginned cotton) from the fractionator
data (expressed as percent by weight of cotton
fiber after fractionation). The accuracy of es-
timation increases as the number of fraction-
ator samples increases, e.g., based on a single
fractionator sample, the estimated discharge of
air pollutant material lies somewhere between
40% to 160% of the value obtained by the frac -
tionator, whereas for 20 fractionator samples,
the estimated discharge lies between 86% to
114% of the mean of the fractionator data. Inter-
mediate values are indicated below:
No. of Fractionator Estimation Limits in
Samples	Percent of Mean
1	40 - 160
5	74 - 126
10	81 - 119
20	86 - 114
Since these analyses show that the fraction-
ator data are indicative of actual field sampling
of air pollution materials discharged during the
ginning process, this device could be used to
evaluate on a nation-wide basis air pollution
originating from cotton gins. Samples of cot-
ton, both hand- and machine-picked, could be
selected on a random basis, and sent to a cen-
tral location for fractionation testing and data
analysis.
1.39%
1.00% - 4.00%
(2) "Introduction to Statistical Analysis, " Dixon, W.J., and Massey, F. J., Jr., p. 110, 1951,

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Applicability of Shirley Analyzer as Air Pollution Indicator
13
Applicability of Shirley Analyzer as Air Pollution Indicator
Ten samples of ginned cotton (5 each hand-
and machine-picked) taken just prior to passing
through the lint cleaner and nine samples
(5 machine- and 4 hand-picked) which had been
processed through the cleaner were analyzed
using the Shirley Analyzer to determine the ap-
plicability of this device for evaluating the
amount of air pollutant material resulting from
the lint cleaning process, Table 6. Results
indicate that samples which had passed through
a lint cleaner contained on the average about
70% as much particulate (noncollected waste)
as did samples which had not passed through the
cleaner.
Statistical evaluation of the tests performed
(Appendix 2) indicates a large variation in test
results, due either to sampling variation or
variation inherent in the analyzer. This varia-
tion is so great that the probability is less than
one in twenty that an actual difference of 30%
would be detected using the Analyzer. It may
be concluded then, that the Shirley Analyzer is
not practical for evaluating the amount of pollu-
tion material resulting from the lint cleaning
operation. By analyzing an even larger number
of samples in the Shirley apparatus, it is prob-
able that the difference of 30% noted above would
be determined to be statistically significant.
However, from the practical standpoint it is not
desirable to employ a laboratory device re-
quiring an excessive number of samples.
This device, however, is satisfactory for
evaluating differences in pollution from the lint
cleaning process due to methods of picking.
Statistical analysis of this same data indicates
that significantly less particulate (noncollected
waste) was obtained for hand-picked cotton, i. e.,
about 58% of that for machine-picking. As
previously noted, the analysis of fractionator
data showed no significant difference between
hand-picked and machine-picked cotton. There
are two possible explanations for this variation.
First, the Shirley Analyzer is more efficient in
cleaning cotton than either the gin or fraction-
ator, and second, before a cotton sample is
placed in the fractionator, all large foreign
materials, such as sticks, stems, leaves, hulls
and seeds are removed by hand. In the ginning
process there is a possibility that some of the
above material is reduced in size, thereby cre-
ating air pollution particulates from waste nor-
mally not considered air pollution material.
Since, as may be seen from the fractionator
data in Tables 4 and 5, machine-picked cotton
does contain more hulls than hand-picked, it is
possible that the ginning operation created the
difference between hand-picked and machine-
picked cotton. In this event the Shirley Analy-
zer, which uses ginned cotton, would show this
difference whereas the fractionator, which
uses unginned cotton, would not.
Since this difference does not appear at pres-
ent to affect the comparison of gin test data and
fractionator data, further consideration will not
be given to this point.
Control Equipment Investigation
Control techniques and equipment for reduc-
tion of particulate emissions must be within the
economic limitation imposed by the marginal
operation of the cotton ginning industry. To
satisfy this economic limitation, several con-
ditions must be met:
1.	Moderate initial cost, and reasonable
operation, cleaning, and maintenance
costs.
2.	Maximum pressure drop not to exceed
about 0. 5 inches of water, so as to
allow use of low cost air moving equip-
ment with nominal power consumption.
3.	Relatively simple means for cleaning
and disposal of waste.
4,	High collection efficiency for all par-
ticle sizes and for operation under
variable flow rates and dust loadings.
After considering specifications and costs of
control devices currently available, it was ap-
parent that no standard equipment would meet
all the requirements.
Because of the relatively high concentration
of lint fibers in the effluent discharge, it was

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14	AIR-BORNE PARTICULATE EMISSIONS FROM COTTON GINNING OPERATIONS
burlap (which is readily available at cotton gins)
as the filter media would best satisfy all of the
requirements. Burlap was chosen as the fab-
ric because of its low cost and high porosity;
hence, its low resistance and ability to main-
tain a high filter velocity. The burlap fibers
initially act as a filtering media for the lint.
Later the lint fibers collected on the burlap
create a closely arranged cotton-fiber filter
surface on the loosely woven coarse burlap fil-
ter cloth. Such a technique results in high ef-
ficiency filtration and still meets the required
economic limitations.
To test this technique, a pilot model was
constructed as shown in Figure 9. This device
consisted essentially of a box, four sides of
which were covered with burlap. Two high
volume samplers provided the suction to pull
the discharge from the gin through the inlet
duct into the filter chamber, through the burlap
filters, and then discharge the clean air to the
atmosphere. Total discharge from the pilot
filter unit was sampled using two high efficiency
glass sampling filters attached to the top of
the pilot unit. The filter area of this pilot de-
vice could be varied by removing a section of
sheet metal and substituting a strip of filter
material. By obtaining the total weight of ma-
terial settled within the device and collected on
the burlap, and that collected on the glass fiber
sampling filters, it was possible to compute
the efficiency of the pilot unit. Pressure taps
were inserted on both sides of the burlap filter
to indicate the pressure loss across the pilot
unit.
.
HIGH VOLUME SAMPLER

&
FLOW METERS
SUCTION CHAMBER
BURLAP FILTER 11
FILTER 1
.CHAMBER"
SAMPLING LINE

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Control Equipment Investigation
15
The pilot device was tested on effluent from
a commercial gin in Mississippi wherein all
effluents were conducted to a single point of
discharge to a dust house. Two filtration ve-
locities were used, one at 30 ft/min. and the
other at 60 ft/min. Formation of the filter
matrix was excellent as shown in Figure 10.
Initial pressure drop and increase in pressure
drop with time were low for both filtration ve-
locities studied. As indicated in Figure 11, the
initial pressure drop for each filtration velocity
was less than 0.02 inches of water andincreased
during a two-hour period to 0. 10 inches of wa-
ter for the 30 ft/min. filtration velocity and to
0. 47 inches of water for the 60 ft/min. velocity.
Particulate loadings in the discharge and the
total mass of particulate collected by the pilot
unit are shown in Table 7. Assuming that inlet
Figure 10. BURLAP FILTER WITH
LINT LOADING
loading was uniform during all four quarters of
the total sampling period, the loading during
each quarter, and the collection efficiency of
the unit during that quarter were calculated.
As may be seen from the results, the tech-
nique appears to be worthy of full-scale trial.
Such a control unit would possess low initial
cost, low pressure drop with a correspondingly
low power requirement, and high collection
efficiency.
It is suggested that a trial full-scale unit be
designed to operate at an approximate filter
velocity of 30 ft/min. Such a design would have
a low pressure drop increase with time and
would require cleaning only every four to eight
hours. For minimal initial cost, the unit
should consist of a wooden frame covered with
open wire screen to support the burlap, be open
sided and roofed with a sufficient overhang to
protect the filters against rain. Cleaning would
be done manually by entering the chamber and
removing the collected lint and dust mass from
the burlap.
I .60
40
FILTER AREA = I SO. FT.
FILTER VEL0CITY=60FT.
PER MIN.-
m
.20
FILTER AREA'2 SQ FT
FILTER VELOCITY * 30 FT
PER MIN.—\
UJ
.10
20
40
SAMPLING TIME (MINUTES)
60
80
100
120
NUTES)
Figure 11. ANTICIPATED PRESSURE

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TABLE 7
BURLAP FILTER TEST RESULTS

TEST A
Filter Area = 2 sq. ft.
Filter Velocity = 30 ft. /min.
TEST B
Filter Area = 1 sq. ft.
Filter Velocity = 60 £t./min.
Time
Interval
(min.)
Loading to
Settling Cham-
ber and Burlap
Filter During
Time Interval
(gms)
Material Col-
lected on Glass-
Fiber Filter
(gms)
Efficiency
of Settling
Chamber and
Burlap Filter
Loading to
Settling Cham-
ber and Burlap
Filter During
Time Interval
(gms)
Material Col-
lected on Glass-
Fiber Filter
(gms)
Efficiency
of Settling
Chamber and
Burlap Filter
0-30
5.025
0.469
91.5%
4.45
0.280
94.1%
30 - 60
5.025
0.159
96.9%
4.45
0.068
98.5%
60 - 90
5.025
0.093
98.2%
4.45
0.053
98.8%
90 - 120
5.025
0.071
98.6%
4.45
0.025
99.4%
TOTAL
20.100
0.792
Avg= 96.2%
17.80
0.426

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Appendix 1
17
Summary
The quantity of particulate emissions from
a typical cotton gin and laboratory devices for
predicting such emissions have been evaluated.
Although the data obtained are limited in scope,
they are believed to be adequate for a general
assessment of the problem. It has been shown
that the standard laboratory fractionator is ef-
fective in establishing the amount of air pollu-
tion material that will be discharged to the at-
mosphere during ginning operations. From the
limited number of areas used in this study, air
pollution emissions from cotton ginning appear
to be about 1-1/2% of the total weight of proc-
essed cotton. Since the gin sampled was se-
lected as typical of such operations, this value
may be assumed to show generally the order
of such discharges from ginning operations.
A pilot model of a device to control particu-
late discharges from cotton gins was designed
based on two common principles employed in
control equipment; namely, gravity settling
and fabric filtration. Tests in the field indi-
cate the method to be much more efficient
(96%-97% removal) than equipment presently
used in ginning operations. A prototype control
device based on the pilot tests is suggested as
a means for economically controlling particu-
late discharges from ginning operations. This
device should be trial tested to establish its
feasibility under full-scale field conditions.
Personnel
The Engineering Research & Development
Unit, Air Pollution Engineering Program, Public
Health Service, carried out the field sam-
pling and laboratory studies for this report.
Messrs. C.M. Merkel, J.V. Shephard, and
E. A. Harrel of Cotton Ginning Laboratories of
the U. S. Department of Agriculture at Stone-
ville, Mississippi, made the necessary arrange-
ments for sampling in the field and assisted in
obtaining field and laboratory data.
Appendix 1
Statistical Evaluation of Cotton Gin Fractionator Data
In this evaluation, the variable X is the
amount of air pollution material contained within
cotton expressed as a percent of dry cotton
by weight. The factor "percent dry cotton" was
determined experimentally as the ratio of the
weight of a 30-50 gram sample of seed cotton
after drying to its weight before drying. Using
data from Tables 5 and 6, a total of 40 such val-
ues of X were available.
A preliminary analysis showed that, for cot-
ton from a given area picked by a given method,
the variation between means of different sam-
ples of cotton was not significantly different
from the variation within measurements ob-
tained from replicate analysis of the same sam-
ple. This then established that sampling intro-
duced no complications in subsequent analyses.
The analysis of variance, therefore, reduced
to a determination of the effect of two factors,
namely area (Clemson and Stoneville) and pick-
ing method (hand and machine). The results of

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18
AIR-BORNE PARTICULATE EMISSIONS FROM COTTON GINNING OPERATIONS
The results of the analysis of variance computations may be summarized in tabular form as
follows:
TABLE 8
MEAN PERCENTAGE AIR POLLUTION VALUES (AVERAGE OF 10 SAMPLES)
Machine-Picked Cotton	Hand-Picked Cotton
Area	X*	95% CI*	X*	95% CI*
Clem son 0.54%** 0.44%- 0.64%	0.79% 0.69%-0.89%
Stoneville 0.91% 0.81%- 1.01%	0.84% 0.74%-0.94%
COMBINED 0.72%	0.81%
**This value is significantly lower than the other three values,	which average 0.85%.
Symbols: X - estimated mean %-air pollution (average of 10 samples)
95% CI - 95% confidence interval for true mean.
TABLE 9
ANALYSIS OF VARIANCE
Source of Variation	„Sum of	Degrees of variance
—		——	Squares	Freedom 	—
I Between Methods of Pick-
ing (M)		0.078234	1 0.0782
II Between Areas (A)		0.444577	1 0.4446
EI A x M Interaction		0.267813	1 0.2678
IV Between Replicate Cotton
Samples		0.232243	10 0.0232
V	Between Replicate Analyses
(Within Samples)		0.674013	26 0.0259
Total		1.696880	39
VI	Poll IV and V		0.906256	36 0.0252
Symbols: N.S. - not significant at 0. 05 probability level.
* - significantly greater than unity at .01 probability level.
F - Ratio
I/m = 0.29 N.S.
n/in - 1.66 N.S.
m/VI = 10.63*

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Appendix 2
19
Appendix 2
Statistical Analysis of Shirley Analyzer Data
A total of nineteen 100 gram samples of
ginned cotton from the Stoneville area, Table 7,
nine of which had been processed through the
gin lint cleaner and ten of which had not, were
dried for one hour at 210° F. Each sample was
weighed and then separated by the use of a
Shirley Analyzer into "cleaned lint" and "col-
lected waste" components which in turn were
also weighed. "Non-collected waste" (the air
pollution fraction) was expressed as a percent-
age of the weight of dried cotton and used as the
response variable X, in the analysis described
below.
The analysis of variance technique was
used to evaluate the effect of two factors, name-
ly picking method (hand and machine) and lint
cleaner (i.e., whether or not the lint cleaner
was used). The results of this analysis are
presented in Tables 10 and 11.
TABLE 10
MEAN PERCENTAGE NON-COLLECTED WASTE VALUES
Machine-Picked Cotton	Hand-Picked Cotton

n
X
95% CI

n
X
95% CI

Total X
Lint Cleaned
5
1.31%
0.90% -
1.72%
4
0.55%
0.09% -
1.01%
0.93%*
Lint Not Cleaned
5
1.66%
1.25%-
2.08%
5
1.10%
0.69% -
1.51%
1.38%*
COMBINED
10
1.49%
1.20%-
1.78%
9
0.86%
0.55% -
1.17%

~Ratio 0.93/1.38 = 68% (about 70%)
Symbols: ji_- number of samples
X - estimated mean % non-collected waste (average of n samples)
95% CI - 95% confidence interval for true mean
TABLE 11
ANALYSIS OF VARIANCE
, . ..	Sum of Degrees of Variance
Source of Variation	squares Freedom Estimate
I Between Methods of Pick-
ing (M)	 1.883304	1	1.8833
II Lint Cleaner (L)	 0.793547	1	0.7935
HI M x L Interaction	 0.188635	1	0.1886
IV Between Replicates
(Exp. Error)	 3.361341	15	0.2241
TOTAL	 6.226827	18
V Pool in and IV	 3.549976	16	0.2219
Symbols: N. S. - not significant at .05 probability level.
** - significantly greater than unity at .01 probability level.
F - Ratio
I/m = 8.49**
H/V = 3.58 N.S.

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20
AIR-BORNE PARTICULATE EMISSIONS FROM COTTON GINNING OPERATIONS
Appendix 3
Glossary
Boll trap - a gravity settling type device.
Condenser - a machine designed to collect ginned
lint into smooth, endless "Bat".
Dust house - rather large tall structure open on
top and sometimes also open on bottom.
Acts as settling chamber and elutriator.
Extractor-feeder - a device which extracts
burs, stems, whole leal, and other trash
from seed cotton and then feeds the cotton
to the huller front gin stand.
Feed control - consists of a sealed paddle-wheel
arrangement to maintain constant flow of
material through the gin.
Huller Front Gin Stand- an arrangement of saws
and air blasts that removes seeds, hulls,
and motes from the cotton, and in addi-
tion, the gin fronts remove appreciable
quantities of leaves and stems, even when
elaborate cleaning and extracting proc-
esses have preceded them.
Leaf trash - small bits of leaf contained in the
lint.
Lint Cleaner - a device designed primarily to
remove fine leaf particles, motes, dust,
sticks, and shale fragments.
Motes - a small group of fibers held together
by a portion of the covering of the seed.
Pin and pepper trash - small pieces of dirt,
sand, etc., that appear as pepper in the
cleaned cotton.
Seed cotton - lint cotton from which the seeds
have not been removed.
Separator - mechanical device which separates
the carrier air stream from the carried
lint. Example: wire screen with rotary
rake.
Seven Cylinder Cleaner - contains seven spiked-
drum cylinders which carry and "scrub"
the seed cotton over wire mesh or perfo-
rated metal screens through which fine
particles of leaf trash, dirt or sand,
stems and small sticks are expelled from
the cotton.
Six Cylinder Cleaner - similar to seven cylin-
der cleaner.
Stick and Bur Machine - employs a revolving
saw cylinder. The teeth of the saw hold
the locks of seed cotton, subject them to
a carding and cleaning action as the cot-
ton is spread across the surface of the
saw cylinder, and strip them of heavy
trash and burs.
Stub tower dryer - a device in which the cotton
follows a tortuous path while being sub-
jected to heated air.
Tower dryer - a longer version of the stub

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