EPA-600/2-78-004a
January 1978
Environmental Protection Technology Series
SOURCE ASSESSMENT: COTTON GINS
Industrial Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine 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 (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental 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 through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-78-004a
January 1978
SOURCE ASSESSMENT:
COTTON GINS
by
6. D. Raw!ings and R. B. Reznik
Monsanto Research Corporation
Dayton, Ohio 45407
Contract No. 68-02-1874
Project Officer
H. Kirk Mil lard
Industrial Pollution Control Division
Industrial Environmental Research Laboratory
Cincinnati, Ohio 45268
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
This report has been reviewed by the Industrial Environmental
Research Laboratory-Cincinnati, U.S. Environmental Protection
Agency, and approved for publication. Approval does not signify
that the contents necessarily reflect the views and policies of
the U.S. Environmental Protection Agency, nor does mention of
trade names or commercial products constitute endorsement or
recommendation for use.
11
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FOREWORD
When energy and material resources are extracted, processed, converted, and
used, the related pollutional impacts on our environment and even on our
health often require that new and increasingly more efficient pollution con-
trol methods be used. The Industrial Environmental Research Laboratory -
Cincinnati (lERL-Ci) assists in developing and demonstrating new and im-
proved methodologies that will meet these needs both efficiently and economi-
cally. '
This report contains an assessment of air emissions from cotton gins. The
study was conducted to provide EPA with sufficient information to decide
whether additional control technology needs to be developed for this emis-
sion source. Further information on this subject may be obtained from the
Food and Wood Products Branch, Industrial Pollution Control Division.
David 6. Stephan
Director
Industrial Environmental Research Laboratory
Cincinnati
iii
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PREFACE
The Industrial Environmental Research Laboratory (IERL) of the
U.S. Environmental Protection Agency (EPA) has the responsibility
for insuring that pollution control technology is available for
stationary sources to meet the requirements of the Clean Air Act,
the Federal Water Pollution Control Act, and solid waste legis-
lation. If control technology is unavailable, inadequate, or
uneconomical, then financial support is provided for the develop-
ment of the needed control techniques for industrial and extract-
ive process industries. Approaches considered include: process
modifications, feedstock modifications, add-on control devices,
and complete process substitution. The scale of the control
technology programs ranges from bench- to full-scale demonstra-
tion plants.
IERL has the responsibility for developing control technology for
a large number of operations (more than 500) in the chemical and '
related industries. As in any technical program, the first step
is to identify the unsolved problems. Each of the industries is
to be examined in detail to determine if there is sufficient
potential environmental risk to justify the development of con-
trol technology by IERL. This report contains the data necessary
to make that decision for cotton ginning.
Monsanto Research Corporation has contracted with EPA to investi-
gate the environmental impact of various industries that represent
sources of emissions, in accordance with EPA's responsibility, as
outlined above. Dr. Robert C. Binning serves
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ABSTRACT
This report summarizes the assessment of air emissions from cot-
ton gins. The study was completed to provide EPA with sufficient
information to determine whether additional control technology
needs to be developed for this emission source.
Cotton gins are used to separate cotton fibers from cottonseed
and trash. During the 1976 crop year, 2.30 x 106 metric tons of
lint cotton were ginned in 18 southern and western states.
Particulates composed of cotton dust, cotton lint, fine-leaf
trash, and other trash are released to the atmosphere during each
step of the ginning process. Emissions are enhanced because
materials are handled by air conveying systems. The average
particulate emission for the entire ginning process is 3.14 g/kg
of cotton ginned.
Potential environmental effects from ginning were assessed by
determining the source severity at a typical plant boundary.
Severity is defined as the ratio of the ground level particulate
concentration to a reduced threshold limit value. Source severi-
ties for nine individual emission points at a typical gin ranged
from 1 to 40, while the severity for one other point was less
than 0.01.
All cotton gins in the United States use a combination of
cyclones, separators, condensers, and inline filters to separate
cotton and trash from the conveying air stream and to reduce air
emissions. The emission factor of 3.14 g/kg is therefore a con-
trolled emission factor. Additional controls are not normally
used by the industry.
This report was submitted in partial fulfillment of Contract
68-02-1874 by Monsanto Research Corporation under the sponsorship
of the U.S. Environmental Protection Agency. This report covers
the period April 1975 to August 1977, and the work was completed
as of August 1977.
v
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CONTENTS
Foreword iii
Preface iv
Abstract v
Figures viii
Tables ix
Abbreviations and Symbols *i
Conversion Factors and Metric Prefixes xii
1. Introduction 1
2. Summary 2
3. Source Description 5
General description 5
Process description 8
Material flow 15
Geographic distribution 19
4. Emissions 23
Emission characteristics ". 23
Representative cotton gin 34
Effect on air quality 38
5. Control Technology 41
State of the art , 41
Future considerations 46
6. Growth and Nature of the Industry 48
Present technology 48
Emerging technology 48
Industry production trends 49
7. Unusual Results 50
References 54
Appendix 58
Glossary 66
vn
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FIGURES
Number Pac
1 Percent distribution of cotton ginned in 1976 5
2 Usual start of cotton harvest 7
3 Predominant types of cotton planted in Texas, Oklahoma,
and New Mexico 7
4 Flow diagram of the cotton ginning process 9
5 Inclined cleaner 11
6 The ginning rib-saw relationship at the point where
ginning takes place 13
7 The gin stand 13
8 Unit saw-type cleaner 14
9 Average composition of dry, picker-harvested seed
cotton 16
10 Average composition of dry, stripper-harvested seed
cotton 16
11 Number of active cotton gins, 1976 19
12 Geographical location of active cotton gins by county,
1976 20
13 Leading 100 cotton ginning counties, 1976 20
14 Typical ginning operation 26
15 Effect of trash content on emission factor 28
16 Effect of field extraction of trash on emission factors 29
17 Effect of feed rate on emission concentration 29
18 Composite of accumulative particle size distribution . 31
19 General distribution of %/F as a function of distance
from the source, showing the two general roots to
the plume dispersion equation 40
20 Relative dimensions for a small-diameter (<96 m),
high-efficiency (>99%) cyclone 42
21 Fixed-screen inline filter with revolving wiping brush 43
Vlll
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FIGURES (continued)
Number Page
22 Revolving-screen inline filter with fixed wiping brush 44
23 Horizontal round inline filter with radial wiping arm 44
24 Standard condenser drum covering overlaid with fine
screen or fine perforated metal 45
25 Trend in cotton production 49
26 Trend in the number of active gins 49
27 Optimum design teepee incinerator 51
TABLES
1 Characteristics of Representative Cotton Gins 2
2 Emission Factors and Source Severities for Cotton Dust
Emissions from a Representative Cotton Gin 3
3 Ginnings of Cotton by State, 1976 6
4 Proportion of Lint, Seeds, and Trash in Dry Seed Cotton 15
5 Particle Size Distribution of Gin Trash 17
6 Application of Pesticides to Cotton Crops in 1971 . . . 21
7 Population Densities of Cotton Ginning Counties
Containing Active Cotton Gins 22
8 TLV's of Pesticides Applied to Cotton Crops 25
9 Emission Factors for Best Available Controlled Cotton
Dust Emissions from a Cotton Gin Processing
Stripper-Harvested Cotton at a Rate of 10 Bales/hr . 28
10 Range of Total Emission Factors as Related to Trash
Content of the Seed Cotton 28
11 Emission Factors for Controlled Cotton Dust Emissions
from a Cotton Gin Processing Picker-Harvested
Cotton at a Rate of 10 Bales/hr 30
12 Pesticide Analysis of Seed Cotton and Trash 32
13 Pesticide Emission Factors 33
14 Trace Element Analysis of Particulate Emissions from
the Unloading Fan at a Gin Processing Midseason,
Picker-Harvested Cotton 34
15 Distribution of Gin Batteries by Capacity in Bales per
Hour for Each State, Region, and United States, 1970 35
ix
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TABLES (continued)
Number
16
17
18
19
20
21
22
Number of Gins, by Size and Normal Operating Schedule
Emission Factors for a Representative Cotton Gin . . .
Mass of Cotton Dust Emitted in the United States . . .
Source Severity for Controlled Cotton Dust Emissions
from a Representative Cotton Gin
Summary of Cost Data for Model Cotton Gin Plants . . .
Design Basis for Model Cotton Gin Plants .......
Summary of Air Pollution Regulations Concerning
36
37
38
40
47
47
Incineration of Gin Trash 51
23 Emission Factors for a Teepee Burner Burning Wood
Waste 53
24 Estimated Soruce Severity and Ymax f°r Emissions from
a Teepee Burner at a Typical Cotton Gin 53
25 Annual Mass of Emissions from Teepee Burners 53
x
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ABBREVIATIONS AND SYMBOLS
a. — standard deviation of A.
A. -- average emission factor from the ith cotton gin
CO — carbon monoxide
e ~ 2.72
F — hazard factor for an emission species
h — stack height, m
^DSQ -- dose that is lethal to 50% of a test population
N — total number of gins
OES — optical emission spectrography
Q -- mass emission rate, g/s
S — source severity
t — averaging time
t -- short-term averaging time
TLV — threshold limit value
u -- national average wind speed (4.5 m/s)
TT -- 3.14
X — ground level concentration of a pollutant
X~ — time-averaged ground level concentration of a
pollutant
X — maximum ground level concentration of a pollutant
max
X~ — time-averaged maximum ground level concentration of a
max pollutant
XI
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CONVERSION FACTORS AND METRIC PREFIXES
CONVERSION FACTORS
a
To convert from
Degree Celsius (°C)
Kilogram (kg)
Kilogram (kg)
Kilogram/meter3 (kg/m3)
Kilometer2 (km2)
Meter (m)
Meter (m)
Meter3 (m3)
Metric ton
Radian (rad)
Second (s)
to
Degree Fahrenheit
Pound-mass (pound mass
avoirdupois)
Ton (short, 2,000 pound
mass)
Pound-mass/foot3
Mile2
Foot
Mile
Foot3
Pound
Degree
Minute
Multiply by
= 1.8 t° + 32
V*r
2.204
1.102 x 10~3
6.243 x 10~2
3.860 x 10"1
3.281
6.215 x 10-^
3.531 x 101
2.205 x 103
5.730 x 101
1.667 x 10~2
METRIC PREFIXES
Prefix Symbol Multiplication factor
Kilo
Milli
Micro
k
m
y
103
10~3
10~6
Example
2 kg
2 mg
2 ym
2 x 103 grams
2 x 10"3 gram
2 x 10~6 meter
Standard for Metric Practice. ANSI/ASTM Designation: E 380-766
IEEE Std 268-1976, American Society for Testing and Materials,
Philadelphia, Pennsylvania, February 1976. 37 pp.
XII
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SECTION 1
INTRODUCTION
Cotton gins are used to separate cotton fibers (lint) from the
cottonseed and to remove trash from the lint. During the ginning
process, cotton dust consisting of dirt, fine-leaf and other
trash, and lint are emitted into the atmosphere. The emission of
cotton dust and lint is enhanced because the ginning operation
uses air to handle the seed cotton, lint cotton, cottonseeds, and
trash. Thus, gins require cyclones, separators, and condensers
to separate the transported material from the conveying air.
Emissions from the ginning process are dependent on the ginning
rate and seed cotton trash content. The major factor affecting
seed cotton trash content is the method of harvesting. The two
primary harvesting methods are machine stripping and machine
picking.
The potential environmental impact of atmospheric emissions from
cotton gins has been investigated and is summarized in this
report. Sources of emissions, their characteristics, and the
process variables that affect the quantity of emissions are
identified. Emissions produced from ginning cotton harvested by
the two primary methods are considered. Air pollution control
measures employed at cotton gins are also described.
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SECTION 2
SUMMARY
In the 1976 crop year, 10.58 x 106 bales of cotton, representing
2.30 x 106 metric tons of lint cotton, were ginned at 2,771 cot-
ton gins spanning 18 southern and western states. Texas ginned
more cotton (31.3%) than any other state and contained the largest
number (29.2%) of active cotton gins. California and Mississippi
ranked second and third, ginning 23.6% and 10.9% of the total and
containing 8.2% and 14.0% of the active gins, respectively.
In this study, atmospheric emissions from cotton ginning were
investigated. This included emissions associated with unloading
of the seed cotton from the trailers, cleaning it, separating the
lint from the seeds, and cleaning and baling the lint. Emissions
from transporting seed cotton to the gin and from the processing
of cottonseeds to produce cottonseed oil or meal were not
considered.
In order to assess the potential environmental impact of cotton
ginning, a representative gin was defined as one having the
characteristics shown in Table 1.
TABLE 1. CHARACTERISTICS OF REPRESENTATIVE COTTON GINS
Annual production 914 metric tons/yr or 4,200 bales/yr
Average production capacity 1,481 kg/hr or 6.8 bales/hr
Operating period 10 hr/day, 6 days/wk, 10 wk/yr, 600 hr/yr
Location In a county having a population density
of 12 persons/km2
Particulates composed of dust, fine-leaf trash, lint, and other
trash are generated during each step of the ginning process. The
emission of cotton dust is enhanced because seed cotton, lint
cotton, seed, and trash are handled almost exclusively by air
conveying systems. As a result, each ginning process step
requires a cyclone, separator, or condenser to separate the pro-
duct or trash from the conveying airstream and discharge the air
to the atmosphere.
al metric ton = 106 grams; conversion factors and metric system
prefixes are presented in the prefatory pages.
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Table 2 summarizes the emission factors at various points in a
representative cotton gin. The emission factors were calculated
from source test data gathered at six gins and representing about
2,000 source test measurements. Plume dispersion calculations were
used to determine xmax» the maximum 24-hr average ground level
cotton dust concentration downwind from a gin, which is also
included in Table 2. The source severity, S, for cotton dust
emissions from gins is defined as the ratio of j to a hazard
factor, F, which consists of a modified thresholcPJimit value
(i.e., 0.2 mg/m3 • 8/24 • 1/100) containing an exposure factor
and a safety factor. Initial calculations revealed that x"max
occurs within 25 m of each source, which is well within the
boundaries of a typical cotton gin. Therefore, the ground level
dust concentration at the property line (204 m from each source)
was used to calculate the source severity values at various
emission points, as(summarized in Table 2.
TABLE 2. EMISSION FACTORS AND SOURCE SEVERITIES FOR COTTON
DUST EMISSIONS FROM A REPRESENTATIVE COTTON GIN
Emission point
Unloading fan
No. 1 dryer and cleaner
No. 2 dryer and cleaner
Trash fan for extractors
Overflow fan
No. 1 lint cleaner condenser
No. 2 lint cleaner condenser
Mote fan
Battery condenser
Master trash fan
TOTAL
Stack
height ,
m
5
5
5
5
5
2
2
5
2
16
.2
.2
.2
.2
.2
.4
.4
.2
.4
.0
c
a
Emission factor,
g/kg
0
0
0
0
0
0
0
0
0
0
3
.305
.258
.160
.027
.246
.942
.277
.262
.337
.330
.144
+
±
±
±
±
±
±
±
±
±
±
0
0
0
0
0
0
0
0
0
0
0
.109
.042
.068
.010
.010
.087
.067
.012
.057
.067
.197
b
Xmax'
yg/m3
8
6
4
0
6
26
7
7
9
<0
.2
.9
.3
.7
.6
.6
.8
.0
.5
.01
c
Source .
severity
12
10
6
1
10
40
12
10
14
<0.01
c
Emission factors calculated from 2,000 source test measurements.
At property line, 204 m from emission source.
Column not additive.
Ihe mass of cotton dust emitted in each of the 18 ginning states
was calculated. Cotton dust emission contributions did not exceed
0.82% of any state's particulate burden and averaged 0.15% for 18
ginning states. On a national basis, emissions from cotton gins
in 1976 represented 0.04% of the total annual particulate emissions.
The affected population was defined as the number of persons
living in the area around the gin where the time-averaged ground
level concentration (x") of emissions divided by the hazard factor
-------
is greater than 1.0. Plume dispersion calculations indicate that
Y is greater than or equal to 1.0 between the gin property line
(204 m from emission source) and 4.1 km from the gin. Within the
annular area, the affected population is 576 persons based on an
average population density of 12 persons/km2.
All cotton gins in the United States use a combination of
cyclones, separators, condensers, and inline filters to separate
the product and trash from the conveying air stream and to reduce
air emissions. Approximately 80% of the gins use covered con-
denser drums instead of inline filters.
The trend in the cotton ginning industry is to replace the smaller
gins (less than 7 bales/hr) with large centralized ones (greater
than 10 bales/hr). Cotton production is expected to grow at a
rate of about 2% to 5% for the next 3 years. Therefore, the
emissions should increase by 2% to 5% over the same period. As
the price of petroleum continues to increase, the increased cost
of synthetic fibers is creating a renewed demand for natural
fibers.
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SECTION 3
SOURCE DESCRIPTION
GENERAL DESCRIPTION
The Bureau of the Census, U.S. Department of Commerce, reports
that 10.58 x 106 bales of cotton representing 2.30 x 106 metric
tons were ginned in the United States during the 1976 crop year
(August 1976 through February 1977) (1). This production rate
represents a 27.5% increase over the amount ginned in 1975, but
an 8.3% decrease from the amount ginned in 1974, and an 18.5%
decrease from that ginned in 1973. Cotton was ginned in 18 south-
ern and western states. Five states—Arizona, Arkansas, Califor-
nia, Mississippi, and Texas—ginned 81.5% of the total quantity
ginned. The geographical distribution of cotton ginned in 1976
is shown in Figure 1.
Figure 1. Percent distribution of cotton ginned in 1976.
The emissions discussed in this report include those from unload-
ing the seed cotton at the gin, cleaning it, separating the lint
from the, seeds, and cleaning and baling the lint. Emissions from
transporting the seed cotton to the gin and from the production
of cottonseed oil or meal are excluded.
(1) Cotton Ginning in the United States, Crop of 1976. U.S.
Department of Commerce, Bureau of the Census, Washington,
D.C., June 1977. 19 pp.
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The quantity of cotton ginned, the number of active and idle gins,
and the average production statistics for gins in the 18 cotton-
producing states are given in Table 3. Texas gins more cotton
(31.3%) than any other state and contains the largest number
(29.2%) of active cotton gins. California and Mississippi rank
second and third, ginning 23.6% and 10.9% of the total and con-
taining 8.2% and 14.0% of the active gins, respectively.
The cotton ginning season usually begins in mid-July in southern
Texas and lasts through January in northern Texas and central
California (Figure 2). In 1976, 90.0% of the cotton in the United
States was ginned in the 3-month period between October 1 and
December 31 (1). However, the length of any given season is
completely dependent upon weather conditions during the growing
and harvesting season. If the summer months are especially dry or
if the early portion of the winter is especially wet, the length
of the season will be significantly shorter, ending as soon as
early December.
TABLE 3. GINNINGS OF COTTON BY STATE, 1976 (1)
State
Alabama
Arizona
Arkansas
California
Florida
Georgia
Kentucky
Louisiana
Mississippi
Missouri
Nevada
New Mexico
North Carolina
Oklahoma
South Carolina
Tennessee
Texas
Virginia
United States
Cotton
Equivalent
217-kg bales
351,131
873,083
779,744
2,492,764,
2,612
196,529.
2,612°
555,135
1,147,891
161,681.
2,612
73,253
73,695
174,969
144,202
225,774
3,316,268,
2,613
10,576,568
ginned
Weight ginned,
metric tons
76,450
190,092
169,769
542,735
569
42,789
569
120,866
249,923
35,203
569
15,949
16,045
38,095
31,396
49,156
722,032
569
2,302,776
Percent
of total
ginned
3.3
8.3
7.4
23.6.
<0.1
1.9
<0.1
5.2
10. '9
1.5
<0.1
0.7
0.7
1.6
1.4
2.1
31.3
<0.1
100
Number of
gins
Active
153
112
312
228
2
105
0
122
388
97
1
46
56
95
99
145
809
1
2,771
Idle
45
10
66
8
2
38
1
21
48
12
0
12
21
10
39
33
122
0
488
Average number
of bales
per gin**
2,295
7,795
2,499
10,933
1,306
1,872
0
4,550
2,958
1,667
2,612
1,592
1,316
1,842
1,457
1,557
4,099
2,613
3 , 817
Average net
weight of
bale , kg
•224.2
221.7
223.1
222.4
230.3
227.3
C
222.8
224.3
219.3
225.9
223.0
224.6
220.0
222.4
220.1
222.0
219.6
222.5
• Number of running bales divided by the number of active gins.
Estimated values because figures were not released to avoid disclosure of information for individual gins.
Not available.
Two basic types of cotton are grown in the U.S.: picker-harvested
(65%) and stripper harvested (35%). Picker-type cotton grows on a
taller plant than the stripper type and is harvested with a spin-
dle picker machine. This machine removes cotton from the bur with
rotating spindles, leaving unopened bolls on the plant and collect-
ing relatively few leaves, burs, and other trash. The smaller,
stripper-type cotton plant is grown in the more arid, irrigated
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E3 Before Aug. 20
B Aug. 20 - Sept. 9
m Sept. 10 - Sept.30
E30ct. 1-Oct. 20
ED After Oct. 20
Figure 2. Usual start of cotton harvest.
areas of Texas, Oklahoma, and eastern New Mexico (Figure 3) (2).
Here yields are relatively low and production costs must be kept
at a minimum. Mechanical strippers are used to harvest this
cotton. These machines strip away both open bolls (with their
burs) and unopened bolls, collecting leaves, burs, sticks, rocks,
and soil in the process. As a result, stripper-type cotton arriv-
ing at the gin contains as much as six times more trash than
picker-type cotton (3).
Figure 3.
STRIPPER TYPE
PICKER TYPE
BOTH TYPES
Predominant types of cotton planted in
Texas, Oklahoma, and New Mexico (2).
(2) Texas Cotton Review, 1973-74. The Univeristy of Texas,
Natural Fiber Economic Research. Research Report No. NFFPC-
NFER-UT-104-74 (PB 235 388), Austin, Texas, July 1974.
143 pp.
(3) Pendleton, A. M., and V. P. Moore. Ginning Cotton to Pre-
serve Fiber Quality. Publication No. ESC-560. U.S. Depart-
ment of Agriculture, Federal Extension Service, Washington,
D.C., September 1967. 19 pp.
7
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In spite of the numerous varieties of cotton grown across the
U.S., there is little variation in the basic cotton ginning pro-
cedures. The five basic ginning steps include the 1) unloading
system, 2) seed cotton drying and cleaning system, 3) overflow
system, 4) lint cotton cleaning and handling system, and 5) bat-
tery condenser and baling press. The largest variation in gin
design is the amount of equipment used in each of the five pro-
cess steps. For example, stripper gins use more equipment for
seed cotton cleaning than picker gins.
There are numerous process steps that remove trash from the
cotton and exhaust pneumatic conveying air to the atmosphere.
Pneumatic conveying systems are used throughout the gin to 1) con-
vey seed cotton from trucks, trailers, or storage; 2) operate
cotton conditioners or dryers; 3) supply necessary volumes of air
to the gin stand and lint cleaner; 4) convey cotton from point to
point in the ginning system; and 5) convey seed, hulls, and trash.
Numerous separators, cyclones, and condensers are used to separate
the cotton, trash, and seed from the conveying system.
PROCESS DESCRIPTION
A detailed flow diagram of a typical cotton ginning process for
picker-type cotton is shown in Figure 4. Gins designed for
stripper-type cotton contain additional equipment such as an air-
line cleaner and anothef stick extractor. Each of the five gin-
ning steps and associated equipment are described in detail below.
Unloading System
Trucks and trailers transport seed cotton from the field to the
gin. Pneumatic systems equipped with telescoping intake tubes
suck the seed cotton from the vehicles and convey it to a separa-
tor and feed control unit. The screen assembly in the separator
removes the seed cotton from the conveying air, permitting it to ,
fall to the feed control unit. The conveying air flows through
the screen and from the separator to a cyclone system where it is
cleaned and discharged to the atmosphere. The feed control unit
serves to 1) minimize chokages in seed cotton cleaners, 2) provide
an even flow of cotton to the dryers and cleaners for efficient
operation, and 3) decrease time loss between bales.
Gins that handle stripper-harvested cotton and other seed cotton
that contains high quantities of trash install a green boll trap
and airline cleaner either before or after the separator and feed
control unit. The green boll trap is an inertial separator that
removes unopened cotton bolls and other heavy foreign matter.
Airline cleaners permit both air and seed cotton to pass entirely
through the cleaner. In this respect they differ from gravity
cleaners. Airline cleaners are used to remove sand from seed
cotton and to break the bolls before cleaning. Trash collected
from these two units together with the trash collected by the
8
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HEATER
NG -H_J NO. 2
A-AIR
T- TRASH
SC - SEED COtTON
S - COTTONSEED
LC-LI NT COTTON
NG - NATURAL GAS
—I
Figure 4. Flow diagram of the cotton ginning process.
-------
cyclones is transported pneumatically or by screw conveyors to
the trash disposal area.
Seed Cotton Cleaning System
Seed cotton is subjected to three basic conditioning processes
before it enters the gin stand for separation of lint from the
seed: drying, cleaning, and extracting. The basic difference
between cotton ginning procedures lies in this process category.
While the gins use basically the same equipment, they vary in the
placement and number of the units within the conditioning process.
To insure adequate conditioning, cotton gins use two similar
conditioning systems, in"series (Figure 4).
The key to preserving quality during ginning is proper moisture
content of the fiber. The higher the moisture content, the more
resistant the fibers are to breakage when subjected to the
stresses of processing. However, the lower the moisture content,
the easier it is to separate the trash from the fiber, and the
more efficient the gin cleaning machines will be.
Cotton dryers are designed to reduce the moisture content of the
seed cotton to an optimum level of 6.5% to 8.0% (3). There are
several types of cotton dryers on the market, but all are varia-
tions of the tower dryer. Heated air conveys the seed cotton
through the tower dryer at about 600 m/min, giving an exposure
time of 10 s to 15 s. The temperature of the heated conveying
air ranges from 180°C at the inlet of the dryer to 65°C at the
discharge end. Heaters for gin drying systems use natural gas,
propane, butane, and propane-butane mixtures for fuel (3, 4).
A push-pull high pressure fan system conveys seed cotton through
the tower dryer to the cleaner system. The seed cotton cleaners
serve the dual purpose of first opening the cotton or breaking up
large wads and, second, removing fine foreign matter such as leaf
trash, sand, and dirt from the seed cotton. The seed cotton
cleaner consists of revolving spiked drums or cylinders, turning
at about 400 rpm, that convey the cotton over a series of grid
rods or screens. This process agitates the cotton, allowing the
fine foreign matter to fall through the screen or grid opening
(Figure 5). The capacity of these cleaners ranges from 6 to 12
bales/hr depending on the width. The cleaners may be used in a
horizontal position or inclined at an angle of 0.52 rad (30°).
The majority (more than 80%), referred to as "inclined cleaners,"
are installed at an angle to conserve space (3).
The large particles of foreign matter are removed from the seed
cotton under an entirely different principle referred to as
(4) Handbook for Cotton Ginners. Agriculture Handbook No. 260.
U.S. Department of Agriculture, Agriculture Research Service,
Washington, D.C., February 1964. 121 pp.
10
-------
INLET
SEED COTTON
OUTLET
TRASH OUTLET
Inclined cleaner
(3).
Figure 5.
"extracting." The extractor, commonly called a stick machine, is
used to remove large particle trash such as sticks, stems, and
burs from the seed cotton. '
Because of the differences in trash content of the seed cotton,
the combination of extracting equipment used is the primary dif-
ference between a gin processing picker-harvested cotton and one
processing stripper-harvested cotton. A gin processing picker-
type cotton uses a stick and green leaf extractor and an
extractor-feeder. Because of the relatively larger amounts of
trash and burs encountered, gins processing stripper-type cotton
use a combination of a bur machine, stick machine, and
extractor-feeder.
The bur machine, used by gins in Texas, Oklahoma, and New Mexico
that process stripper-harvested cotton, removes the burs from the
seed cotton. The bur trash is pneumatically conveyed to the trash
storage area, and the seed cotton falls into the stick machine.
The latter machine removes other large trash particles consisting
of sticks, leaf trash, and stems. This machine is replacing the
less efficient bur machine in gins where cotton is not stripped.
Seed cotton issues from the extractor unit and is pneumatically
conveyed through the second conditioning system, consisting of a
tower dryer, inclined cleaner, stick machine, distributor, and
extractor-feeder. If the seed cotton has a moisture content less
than 6.5%, the tower dryer is replaced by a moisture addition
unit (5).
(5) Feairheller, W. R., and D. L. Harris. Particulate Emission
Measurements from Cotton Gins, J. G. Boswell Co., El Rico #9,
Corcoran, California. EMB Project Report No. 72-MM-19, U.S.
Environmental Protection Agency, November 1974. 424 pp.
11
-------
In general (more than 60% of the gins), the trash from the extrac-
tors is combined in a common high-pressure pneumatic system and
sent to a bank of cyclones. The trash collected in the cyclones
is carried (by screw or pneumatic convection) to the trash stor-
age area. The trash from each of the inclined cleaners is
separately conveyed pneumatically to its own cyclone system. The
trash collected by these cyclones is also conveyed to the trash
storage area (Figure 4).
Overflow System
Seed cotton issues from the second inclined cleaner into a screw
conveyor distributor. This distributor apportions the seed cot-
ton to the extractor-feeders at a rate controlled by the gin stand
capacity. When the flow of seed cotton from the screw distribu-
tor exceeds the total intake rates of the extractor-feeders, the
excess seed cotton flows into the overflow hopper.
A pneumatic system picks up seed cotton from the overflow hopper
as required by the extractor-feeder. A separator removes the seed
cotton from the conveying air, dropping it back into the screw
distributor and discharging the air into a bank of cyclones.
Lint Cotton Handling System
The gin stand, which is the heart of the gin, embodies the basic
ginning principle that has remained unchanged since its invention
by Eli Whitney in 1792. Basically, it consists of saws turning
between ribs. The saw teeth pass between the ribs at the ginning
point approximately parallel to the rib face to avoid a shearing
action that would cut the fibers (Figure 6). Cotton enters the
gin stand through a huller front which performs some cleaning
action (Figure 7). The saw grasps the locks of cotton, drawing
them through a widely spaced (50 mm) set of "huller ribs" that
strip off hulls and sticks, allowing them to fall out of the
machine.
The locks are drawn into the roll box from the huller ribs, where
the removal of the fibers from the seeds takes place. As the
seeds are cleaned, they slide down the face of the ginning rib
and fall out the bottom of the gin stand to be conveyed to the
seed house by a screw conveyor or pneumatic system. The lint is
removed from the saw by a blast of air or a brush. This process
is known as "doffing." The lint is then conveyed by air to the
lint cleaning system for final cleaning and combing before baling.
The lint cotton from the gin stand is removed from its low pres-
sure conveying air stream by a condenser that forms the lint into
a batt. This batt is fed into the first set of lint cleaners,
where saws comb the lint cotton and remove leaf particles, grass,
and motes (immature seeds with short, immature fibers attached).
A lint cleaner is shown in Figure 8. The lint cleaning saw, a
cylinder covered with a continuous ribbon saw, rotates at
12
-------
GINNING RIB
3921- 1
Figure 6. The ginning rib-saw relationship
at the point where ginning takes
place (3) .
3921-2
Figure 7. The gin stand (3)
13
-------
CONDENSER DRUM ASSEMBLY
DOFFING ROLLERS
COMBING ROLLER
FEED BAR
GRID BARS
SAW CYLINDER
ASSEMBLY
Figure 8. Unit saw-type cleaner (4).
about 1,000 rpm. The cleaned lint is removed from the saw by a
brush that also provides the air to convey the lint to the second
set of lint cleaners.
The low pressure air discharged from each lint cleaner condenser
passes through an inline filter for lint fly removal before being
exhausted to the atmosphere. The trash collected from both sets
of lint cleaners is combined in a pneumatic system and conveyed
by a mote fan to a set of cyclones.
Battery Condenser and Baler
Lint cotton is pneumatically conveyed by low pressure fans from
the lint cleaning system to a battery condenser. The battery
condenser contains a condenser drum covered with a screen that
separates the lint cotton from the conveying air. The conveying
air is discharged through an inline filter before being exhausted
to the atmosphere.
14
-------
The batt of lint cotton is then fed into the baling press, which
packs it into uniform bales of cotton.
MATERIAL FLOW
The quantity of material flowing through a cotton gin depends on
the gin's capacity, the rate at which the seed cotton is harvested
and transported to the gin, and the type of cotton. It takes more
(47%) stripper-type seed cotton than picker-type cotton to produce
a bale of lint cotton because of the relative trash contents of
the two types of seed cotton (Table 4) (6, 7). The values in
Table 4 also show the breakdown of seed cotton in terms of lint,
seed, and trash content. Figures 9 and 10 further illustrate the
compositions of picker-type and stripper-type seed cotton.
TABLE 4. PROPORTION OF LINT, SEEDS, AND
TRASH IN DRY SEED COTTON (6, 7)
Component
Machine-
picked
Machine -
stripped
Weight of dry seed cotton required to
produce a 227-kg bale of lint cotton:
Range, kg
Average, kg
Lint content, kg
Percent of seed cotton
Seed content
Range, kg
Average, kg
Percent of seed cotton
Trash content
Range, kg
Average, kg
Percent of seed cotton
Composition, %
635 to 900
680
227
33
320 to 450
360
54
45 to 115
90
13
900 to 1,100
1,000
227
23
340 to 450
410
41
320 to 545
360
36
Burs
Sticks
Leaf and dirt
35
15
50
65
15
20
(6) Survey of Particulate Emissions, Frisby-Bell Cotton Gin,
LaVilla, Texas, April 1 to August 31, 1971. Texas Air Con-
trol Board, Austin, Texas, September 1971. 31 pp.
(7) Durrenberger, C. Cotton Gin Report. Texas Air Control Board,
Austin, Texas, May 31, 1974. 50 pp.
15
-------
TRASH 13 %
Figure 9. Average composition of dry,
picker-harvested seed cotton.
Figure 10. Average composition of dry,
stripper-harvested seed cotton.
16
-------
Machine-stripped cotton contains an average of four times more
trash than machine-picked cotton. A 10-bale/hr gin will produce
900 kg/hr of trash when ginning machine-picked cotton and
4,000 kg/hr of trash when ginning machine-stripped cotton. The
particle size distribution of gin trash is given in Table 5 (8, 9)
TABLE 5. PARTICLE SIZE DISTRIBUTION OF GIN TRASH
Particle size,
Vim
>3,300
420 to 3,300
74 to 420
<74
>150
50 to 150
25 to 50
10 to 25
5 to 10
0 to 5
Stripper trash (8)
67.5
27.2
4.5
0.8
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
Percent by weight
Picker trash (8)
49.8
42.3
5.7
2.2
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
Picker trash (9)
N.A.9
N.A.
N.A.
N.A.
96.7
0.5
1.1
1.0
0.3
0.4
TOTAL
100
100
100
Not applicable; not measured in the original report.
Approximately 90% to 99% of the trash is removed from the seed
cotton during the entire ginning process (10). A bur machine
removes 7% to 12% of the total trash in picker-type seed cotton.
It is about 75% efficient at removing burs and 35% efficient at
removing sticks. The stick and green leaf machine is 13% to 20%
efficient at removing total trash content of picker-type cotton
(personal communication, Mr. Garner, USDA Cotton Ginning Research
Laboratory, Stoneville, Mississippi, May 6, 1975). At one gin
processing stripper harvested cotton, 98% of the burs, 95% of the
(8) Baker, R, V., and V. L. Stedronsky. Gin Trash Collection
Efficiency of Small Diameter Cyclones. Publication No. ARS
42-133, U.S. Department of Agriculture, Washington, D.C.,
July 1967. 16 pp.
(9) McCaskill, D. L., and R. A. Wesley. Tests Conducted on
Exhausts of Gins Handling Machine Picked Cotton. The Cotton
Gin and Oil Mill Press. September 5, 1970. 12 pp.
(10) Criteria for a Recommended Standard - Occupational Exposure
to Cotton Dust. Publication No. (NIOSH)75-118, U.S. Depart-
ment of Health, Education, and Welfare, Washington, D.C.,
1974. 159 pp.
17
-------
sticks, and 57% of the fine trash were removed before the dis-
tributor (11) .
The trash collected by all cyclone systems at a gin is pneumatic-
ally conveyed by a master trash fan to a trash disposal area. A
cyclone system separates the conveying air from the trash and
drops the trash into a storage bin. A 1965 survey revealed that
37% of the cotton gins in the U.S. incinerated the trash, 59%
returned the trash to the land, and 5% disposed of the trash by
other methods (12). However, the Clean Air Act of 1970 bans open
incineration of cotton gin wastes except for a few isolated cases
under EPA supervision (13).
The number of fans required and the amount of air moved during
ginning vary with the size of the plant and with the method of
harvest. The number of fans also depends on the types of equip-
ment used and their arrangement in the ginning sequence.
The amount of air moved per fan by high pressure fans handling
seed cotton and trash ranges from 57 to 312 m3/min. The number of
fans required varies from 10 in the 6-bale/hr gin designed for
machine-picked cotton to 24 in the 36-bale/hr gin for machine-
stripped cotton. More fans and greater air volumes are required
for gins processing machine-stripped cotton because they must
handle more material to produce a bale of lint as a result of the
higher trash content of this cotton type.
Discharges from these fans carry varying amounts of dust, trash
particles, and lint into the atmosphere. Dry cyclones, inline
.filters, and condenser coverings are used by all gins to reduce
these emissions.
During the growing season, cotton crops are sprayed with all types
of pesticides; e.g., fungicides, herbicides, insecticides, miti-
cides, fumigants, defoliants, and desiccants. Pesticide residues
can accumulate on and in the cotton plant and cotton boll.
(11) Parnell, C. B., Jr., and R. V. Baker. Particulate Emissions
of a Cotton Gin in the Texas Stripper Area. Production
Research Report No. 149, U.S. Department of Agriculture,
Agricultural Research Service, Washington, D.C., May 1973.
18 pp.
(12) Pendleton, A. M. Current Gin Trash Disposal Practices. In:
Control and Disposal of Cotton-Ginning Wastes. Publication
No. 999-AP-31, U.S. Department of Health, Education, and Wel-
fare, Public Health Service, Cincinnati, Ohio, 1967.
pp. 39-44.
(13) Wilmot, C. A., Z. M. Looney, and 0. L. McCaskill. The Cost
of Air Pollution Control to Cotton Ginners. Publication
No. ERS-536, U.S. Department of Agriculture, Economic
Research Service, Washington, D.C., February 1974. 35 pp.
18
-------
Therefore, the cotton dust and lint emitted during the ginning
process may contain trace quantities (less than 1%) of these
pesticides.
The quantities of pesticides used and the areas treated with
these pesticides in 1971 are given in Table 6 (14).
To date, the Environmental Protection Agency has banned the pes-
ticides aldrin, dieldrin, DDT, chlordane, heptachlor, 2,4-D, and
2,4,5-T. Further tests are being conducted on the environmental
effects of the fungicide ethylenebisdithiocarbamate. EPA has
confirmed that methyl parathion, parathion, malathion, phorate,
and demeton are fully suitable substitutes for certain uses of
DDT (15).
GEOGRAPHIC DISTRIBUTION
The number of active cotton gins in each of the 18 ginning states
is shown in Figure 11. For illustrative purposes, the geograph-
ical location of the 502 counties in the U.S. containing active
cotton gins is shown in Figure 12. Figure 13 shows the 100 lead-
ing cotton ginning counties and illustrates the four major cotton
producing regions. These 100 counties gin 81.5% of the cotton
and contain 60.8% (1,686) of the active cotton gins (1).
The population densities of the 445 ginning counties and the num-
ber of active gins located in these counties are given in Table 7.
The table shows that the majority (75.7%) of the counties contain-
ing gins have population densities less than 20 persons/km2 and
contain 66.7% of the active gins.
56
(2.0%)
99
O.6HI
153 \(3.8%)
388 \<5.5%)
(14.0*1
122
(4.4%)
Figure 11. Number of active cotton gins, 1976 (1).
(14) Andrilenas, P. A. Farmer's Use of Pesticides in 1971. .
Quantities. Agricultural Economic Report No. 252, U.S.
Department of Agriculture, Economic Research Service,
Washington, D.C., July 1974. 56 pp.
(15) Gibney, L. EPA Seeks Substitutes for Banned Pesticides.
Chemical and Engineering News, 53(23)15-16, June 9, 1975,
19
-------
Figure 12. Geographical location of active
cotton gins by county, 1976.
Figure 13,
Leading 100 cotton gin-
ning counties, 1976.
20
-------
TABLE 6» APPLICATION OF PESTICIDES TO COTTON CROPS IN 1971 (14)
Type of pesticide
Inorganic fungicides :
Copper sulfate
Organic fungicides:
Dithiocarbamates
Zineb
Others
Phthalimides
Captan
Dinocap, dodine, quinones
Phenols
Other organics
Total fungicides (excluding sulfur)
Sulfur
Total fungicides
Inorganic herbicides
Organic herbicides :
Arsenicals
Phenoxys :
2,4-D
Other phenoxys
Phenyl ureas :
Diuron
Linuron
Fluometuron
Other phenyl ureas
Amides :
Alanap
Alachlor
Other amides
Carbamates
Dinitro group
Triazines
Other organics :
Trifluralin
Hitralin
Dalapon
Korea
Others
Total herbicides
Inorganic insecticides
Synthetic organic insecticides:
Organochlorines :
Strobane
DDT
Endrin
Dieldrin
Toxaphene
Organophosphorus :
Disulfoton
Bidrin
Methyl parathion
Parathion
Halathion
Trichlorofon
Azinphosmethyl
Phorate
Ethion
Others
Carbamates :
Carbaryl
Methomyl
others
other synthetic organics
Total insecticides
Hiticides:
Dicofol
Chlorobenzilate
Omite
Others
Fumigants :
Dibromochloropropane
Telone
others
Defoliants and desiccants:
Arsenic acid
DEP and folex
Others
Total miscellaneous pesticides
TOTAL PESTICIDES
Quantity applied
to cotton crops
(active ingredients) ,
metric tons
11. 8
5.4
15.4
2.3
6.8
33.6
24.5
99. B
6,839.4
6,939.2
252.7
3,433.3
l.B
27.7
257.6
24.0
1,512.3
19.1
1.8
1.8
85.3
1.4
173.3
365.6
2,061.2
226.8
8.2
383.8
57.6
8,895.1
31.3
98.0
5,968.5
484.4
29.5
12,751.6
102.1
352.9
10,427.4
1,161.2
303.9
65.3
130.6
45.4
2.7
733.5
550.7
18.1
16.8
0.9
33,274.7
85.7
11.3
2.7
28.1
95.7
279.4
152.9
2,744.7
2,269.8
2,810.1
8,480.5
57,589.5
Treated area,
tan2
210.4
24.3
93.1
36.4
109.3
295.4
566.6
1,335.5
2,699.3
4,034.9
1,072.5
16,685.8
20.2
1,161.5
3,140.5
890.3
17,021.7
234.7
68.8
8.1
437.1
72.8
1,036.0
4,524.6
27,535.8
2,088.2
89.0
1,695.7
1,817.1
79,600.4
93.1
72.8
9,644.0
1,060.3
704.2
13,253.9
2,238.0
7,272.5
25,836.0
2,760.0
1,104.8
773.0
481.6
736.6
121.4
4,921.1
987.5
339.9
267.1
97.1
73,655.4
.955".!
206.4
44.5
457.3
97.1
56.7
934.9
3,731.3
14,723.0
4,188.7
25,394.9
182,685.6
21
-------
TABLE 7. POPULATION DENSITIES OF COTTON GINNING COUNTIES CONTAINING ACTIVE COTTON GINS
ro
0 to 5
persons/km2
State
Alabama
Arizona
Arkansas
California
Florida
Georgia
^Louisiana
Mississippi
Missouri
New Mexico
North Carolina
Oklahoma
South Carolina
Tennessee
Texas
Others
TOTAL
No. of
ginning
counties
0
5
0
0
0
0
0
1
0
8
0
9
0
0
49
1
73
Ho. of
active
gins
0
60
0
0
0
0
0
2
0
31
0
30
0
0
280
1
404
5 to 20
persons/km2
No. of
ginning
counties
32
2
26
6
2
35
16
44
5
1
6
12
13
15
43
1
264
No. of
active
gins
71
9
176
153
2
83
87
287
44
15
10
60
30
91
326
1
1,445
20 to 50
persons/km2
No. of
ginning
counties
10
1
5
2
0
9
2
8
3
0
9
3
13
4
14
0
83
No. of
active
gins
54
43
132
75
0
21
24
97
53
0
37
5
61
48
111
0
761
Population
. density
50 to 100
persons/km2
No. of
ginning
counties
4
0
0
0
0
1
1
1
0
0
4
0
2
0
2
0
15
No. of
active
gins
27
0
0
0
0
1
9
2
0
0
8
0
5
0
65
0
117
100 to 200
persons/km2
No. of
ginning
counties
1
0
1
0
0
0
1
0
0
0
1
0
2
0
2
0
8
No. of
active
gins
1.
0
4
0
0
0
2
0
0
0
1
0
3
0
25
0
36
>200
persons/km2
No. of
ginning
counties
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
0
2
No. of
active
gins
0
0
0
0
0
0
0
0
0
0
0
0
0
6
2
0
8
Total
NO. Of
counties
with
active
gins
47
8
32
8
2
45
20
54
8
9
20
24
30
20
116
2
445
Total
No. of
active
gins
153
112
312
228
2
105
122
388
97
46
56
95
99
145
809
2
2,771
-------
SECTION 4
EMISSIONS
EMISSION CHARACTERISTICS
Selected Emission Species
Particulates composed of dust, fine-leaf trash, lint, and other
trash are generated during each step of the cotton ginning pro-
cess. The emission of cotton dust is enhanced because seed cot-
ton, lint cotton, seed, and trash are handled almost exclusively
by air conveying systems. As a result, each ginning process step
requires a cyclone, separator, or condenser to separate the prod-
uct or trash from the conveying air and discharge the air to the
atmosphere. Gins use 10 to 24 cyclones, depending on ginning
capacity.
Emissions from the unloading fan, inclined cleaners, trash fan,
and overflow system consist of dust and fine-leaf trash. Emis-
sions from the gin stand, lint cleaner condensers, mote fan, and
battery condensers contain lint fly and cotton dust.
The threshold limit value (TLV®) established by the American
Conference of Governmental Industrial Hygienists for nonlint
cotton dust is 0.0002 g/m3 of air (16). The acute local, acute
systemic, and chronic local inhalation toxic hazard rating for
cotton dust is moderate (17).
Cotton dust emissions from gins may also contain trace quantities
(less than 1%) of pesticides, defoliants, and desiccants. The
predominant pesticides sprayed on cotton fields in 1971 were DDT,
toxaphene, and methyl parathion (Table 6). To reduce the amount
of green leaves and stems on the stalk where harvesting is to be
done with a spindle picker, a chemical defoliant is applied to
cotton fields when 60% of the bolls are open. Defoliation also
(16) TLVs® Threshold Limit Values for Chemical Substances and
Physical Agents in the Workroom Environment with Intended
Changes for 1976. American Conference of Governmental
Industrial Hygienists, Cincinnati, Ohio, 1976. 94 pp.
(17) Sax, N. I. Dangerous Properties of Industrial Materials,
Third Edition. Reinhold Book Corp., New York, New York,
1968. p. 591.
23
-------
reduces the population of insects that feed on the green cotton
leaves in the late season. The predominant (greater than 90%)
defoliants used in 1971 were sodium chlorate and tributylphos-
phorotrithioites (DEF and Folex).
When stripper machine harvesting is to be done before frost, a
chemical desiccant is applied to the field to reduce the moisture
content of the leaves and stems. Cotton desiccation is primarily
used in the uplands of Central Texas and the Blackland area and
nonirrigated areas of South Texas. The predominant desiccants
used on cotton crops are arsenic acid and paraquat. The TLV's
for the .pesticides, defoliants, and desiccants applied to cotton
are shown in Table 8.
In experimental toxicology, it is common practice to determine the
quantity of poison per unit of body weight (of an experimental
animal) that will have a fatal effect. The values are expressed
as milligrams of poison per kilogram of body weight. A commonly
used concentration figure is the amount of poison that will kill
one-half of a group of experimental animals. This is known as the
LD50 test (Lethal Dose—50%). When TLV's are not available, LD50
values can be used to estimate the relative toxicity of a
chemical.
Emission Factors
The numerous exhaust points at a gin can be arranged into 10
emission source categories based on specific ginning operations
(Figure 14). Conveying air transports the seed cotton, lint
cotton, and seed from one process step to the next. In addition,
trash is conveyed away from each process step by air. Cyclones
and inline filters are used to remove the air from the trash. The
trash is then conveyed by air or screw conveyors to the trash
hopper, and the conveying air is discharged to the atmosphere.
Cyclone exhausts are located 4 m to 15 m above the ground and
inline filter and condenser exhausts are located 1.5 m to 5.0 m
above the ground (personal communication, C. B. Parnell, Jr.,
Texas Agricultural Extension Service, Texas A&M University, Col-
lege Station, Texas) (18).
Fugitive dust emissions result when the trash hoppers are emptied
into trucks. During ginning periods, the trash hoppers are
emptied from one to four times a day (6).
A literature search of both public and private information sources
revealed six sets of reliable source test data. The data were
judged reliable based on the gin sampled, sampling methods employed,
(18) Taylor, M., M. Preusse, D- Johnson, and R. Wallis. Particu-
late Survey of Cotton Gin Operations, Lubbock and Lubbock
County, December 1971-January 1972. Texas State Department
of Health, Air Pollution Control Services, Austin, Texas,
December 1972. 19 pp.
24
-------
TABLE 8. TLV's OF PESTICIDES APPLIED TO COTTON CROPS (16, 17)
Type of pesticide
Inorganic fungicides:
Copper sulfate
Organic fungicides:
Dithiocarbamates
Zineb
Phthalimides
Captan
Dinocap , dodine , quinones
Phenols
Organic herbicides:
Arsenicals
Phenoxys
2,4-D
Phenyl ureas :
Diuron
Linuron
Fluometuron
Amides:
Alanap
Alachlor
Carbamates, see insecticides
Dinitro groups
Triazines
Other organics :
Trifluralin
Nitralin
Dalapon
Korea
Synthetic organic insecticides:
Organochlorines :
Strobane
DDT
Endrin
Dieldrin
Toxaphene
Organophosphorus :
Disulfoton
Bidrin
Methyl parathion
Parathion
Trichlorfon
Az inphosmethy 1
Phorate
Ethion
Carbamates:
Carbaryl
Methomyl
Miticides:
Dicofol
Chlorobenzilate
Omite
Fumigants:
Dibromochloropropane
Telone
Defoliants and desiccants:
Arsenic acid
DBF
Folex
Sodium chloride
TLV, mg/m3a
1.0
(5.0)
(5.0)
0.4
19.0
0.5
10.0
(5.0)
(5.0)
(5.0)
(5.0)
(5.0)
(0.1)
(5.0)
(10.0)
(5.0)
(1.0)
(5.0)
0.5
1.0
0.10
0.25
0.5
(0.1)
(0.1)
0.2
0.1
(1.0)
0.2
(0.1)
(0.1)
5.0
(0.1)
(1.0)
1.0
(5.0)
(0.1)
(0.1)
0.25
(1.0)
(5.0)
(5.0)
Acute oral LD5Q,
mg/kg
300
>5,200
9,000
300 to 1,000
3,400
1,500 to 4,000
8,900
8,200
1,200
10 to 60
3,000 to 5,000
>10,000
2,000
970
2,000
220
113 to 118
5 to 17.8
46
80 to 90
12.5
15 to 22
14 to 24
3.6 to 13
560 to 630
11 to 13
1.1 to 2.3
27 to 65
500 to 850
17
809
960
2,200
173
250 to 500
48 to 100
350
1,272
1,200
aValues in parentheses are assumed TLV's based on their LDs0'
according to the following schedule:
TLV = 0.1 if LD50 <300 mg/kg
TLV - 1.0 if 300 10,000 mg/kg
25
-------
EMISSIONS
EMISSIONS
EMISSIONS
EMISSIONS
EMISSIONS
EMISSIONS
EMISSIONS
EMISSIONS
EMISSIONS
Figure 14. Typical ginning operation,
26
-------
the number of samples collected, and the standard deviation of the
emission averages at each source. Gins A and B (Appendix) were
USDA research cotton gins equipped with the best ginning and con-
trol equipment and operating with maximum efficiency. Gin C was
sampled by a private consulting company as requested by the Texas
Air Control Board for the purposes of collecting data and develop-
ing source sampling procedures applicable to agricultural process-
ing industries. Gins D, E, and F were sampled by Monsanto Research
Corporation in order to determine emissions from cotton gins
equipped with the best available air pollution control equipment.
% ' L
Before sampling at each gin, all cyclone, inline filters, conden-
ser, and wet scrubber exhausts were equipped with stack exten-
sions, as required by EPA stack sampling procedures. The sampling
ducts were sized so as not to affect the back pressure (and con-
trol efficiency) of the control devices. All sampling tests were
conducted under isokinetic conditions. In addition, samples were
collected only when the exhaust air had been used to actively
convey materials within the ginning system.
Stripper-Harvested Cotton—
Table 9 lists emission factors for gins processing stripper-
harvested cotton, the results of emission test data from Gin A.
The raw data and a description of Gin A are presented in
Appendix A. This gin is equipped with cyclones and inline fil-
ters on all the fan exhausts»
TABLE 9. EMISSION FACTORS FOR BEST AVAILABLE CONTROLLED COTTON-
DUST EMISSIONS FROM A COTTON GIN PROCESSING STRIPPER-
HARVESTED COTTON AT A RATE OF 10 BALES/HR
Test cottons3
Early season
Emission source
Unloading fan
No. 1 dryer and cleaner
No. 2 dryer and cleaner L
Trash fan for extractors
Overflow fan and distributor
No. 1 lint cleaner condenser
No. 2 lint cleaner condenser
Mote fan
Battery condenser
Master trash fan
TOTAL
g/kg
0.455 i 0.105
0.102 ± 0.010
0.058 ± 0.005
-
0.191 + 0.073
0.736 ± 0.096
0.106 ± 0.009
0.177 ± 0.015
0.154 ± 0.026
0.076 ± 0.012
2.055 ± 0.164
Percent
of
total
22.2
5
2.8
9.3
35.8
5.2
8.6
7.5
3.7
100
Midseason
g/kg
0.351 ± 0.209
0.357 ± 0.049
0.135 ± 0.017
—
0.303 ± 0.010
1.229 ± 0.113
0.166 ± 0.017
0.247 ± 0.024
0.155 ± 0.020
0.410 ± 0.062
3.353 ± 0.254.
Percent
of
total
10.5
10.6
4
9
36.7
5
7.4
4.6
12.2
100
Late season
g/kg
0.664 ± 0.150
0.349 ± 0.033
0.152 ± 0.018
—
0.103 ± 0.009
2.219 ± 0.385
0.189 ± 0.038
0.279 ± 0.043
0.144 ± 0.021
0.323 ± 0.030
4.422 ± 0.421
Percent
of
total
15
7.9
3.4
2.3
50.2
4.3
6.3
3.3
7.3
100
Extremely dixty
g/kg
3.454 ± 0.55
0.843 ± 0.067
0.264 ± 0.027
—
0.167 ± 0.018
2.377 ±0.315
-
0.462 ± 0.03S
0.200 ± 0.017
0.520 ± 0.066
8.287 ± 0.643
Percent
of
total
41.7
10.2
3.2
2
28.7
5.6
2.4
6.3
100
Average trash content of the four test cottons is 24.74%, 28.80%, 29.80%, and 36,49%, respectively.
Combined with master trash system.
No sample.
Approximately 1,100 source test samples were collected from 10
emission points at this gin (11). All emission values not falling
within plus or minus three standard deviations were rejected
before the calculation of the final average and standard devia-
tion. The uncertainty values on the emission factors are 95%
27
-------
confidence limits calculated from the individual source
measurements.
As Table 9 indicates, the emission factors are greatly influenced
by the trash content of the seed cotton. The longer the open boll
remains on the cotton plant, the more trash it accumulates. A
threefold increase in the total emission factor was experienced
when the trash content was increased from 24.74% to 38.25%. A
linear regression analysis of the total emission factor as a
function of trash content yielded a zero order correlation coeffi-
cient of 0.989 and a standard error of the estimate equal to 1.64
(Figure 15) (11).
8.0
Ol
* 6.0
a:
g
£ 4.0
t/i
to
= 2.0
0 24
28 30 32 34
TOTAL TRASH CONTENT, %
36
38
Figure 15. Effect of trash content on emission factor (11).
The extremely dirty seed cotton (test 4) was a result of an
improperly adjusted mechanical stripper harvester. A mechanical
defect allowed the stripper mechanism to descend so low that
large amounts of loose soil were picked up and mixed with the
seed cotton. These emission values are included to indicate
maximum dust emission factors from a gin processing stripper-
harvested cotton.
A further illustration of the variation in emission factors as a
result of fluctuations in seed cotton trash contents is given in
Table 10. The ranges of total emission factors and trash con-
tents were obtained by summing the averages minus the confidence
limits and the averages plus the confidence limits.
TABLE 10. RANGE OF TOTAL EMISSION FACTORS AS RELATED
TO TRASH CONTENT OF THE SEED COTTON (11)
Test
Item
Emission factor, g/kg
Trash content, %
Early
Low
1.70
23.34
season
High
2.40
26.11
Midseason
Low
2.83
27.82
High
3.
29.
87
78
cottons
Late
Low
3.69
28.41
season
High
5.15
31.20
Extremely
Low
7.19
34.73
dirty
High
9.38
38.25
28
-------
Emission factors can also be influenced by the use of field
extraction harvesting units. These harvesters remove trash from
the seed cotton as it is harvested. Emission tests conducted on
field extracted stripper-type cotton showed a decrease in the
total emission factors ranging from 1% to 36% (Figure 16) (11).
o
R
o
00
00
-------
Picker-Harvested Cotton—
Emission factors for gins processing picker-harvested cotton are
given in Table 11. These values were determined by averaging the
appropriate emission factors from the source test data for Gins B
through F. The raw data and a description of each gin are given
in Appendix A. Each of these gins is equipped with cyclones and
inline filters or condenser drum coverings on all the fan exhausts.
TABLE 11. EMISSION FACTORS FOR CONTROLLED COTTON DUST
EMISSIONS FROM A COTTON GIN PROCESSING PICKER-
HARVESTED COTTON AT A RATE OF 10 BALES/HR
Emission source
Emission factor, g/kg Percent
Low Average of total
Unloading fan
No. 1 dryer and cleaner
No. 2 dryer and cleaner
Trash fan for extractors
Overflow fan"
No. 1 lint cleaner condenser
No. 2 lint cleaner condenser
Mote fan
Battery condenser
Master trash fan
TOTAL
1.34 0.032 0.259 ± 0.079 8.8
0.690 0.005 0.158 ± 0.068 5.4
0.73 0.003 0.185 ± 0.135 6.3
0.198 0.006 0.052 ± 0.028 1.8
0.303 0.103 0.19 ± 0.019 6.5
2.784 0.127 0.655 ± 0.132 22.3
1.122 0.072 0.388 ± 0.134 13.2
0.385 0.162 0.277 ± 0.05 9.5
1.05 0.110 0.519 ± 0.114 17.7
0.816 0.034 0.250 ± 0.12 8.5
9.418 0.654 2.933 ± 0.302 100
Based on largest single emission factor reported from the gins sampled.
Estimated emission factor based on the average of the emission factors
for stripper-harvested cotton because no source test measurements were
made from this source for picker-harvested cotton.
The uncertainty values associated with each emission factor were
calculated from the standard deviations of the averages reported
from each gin's source test measurements and computed in the fol-
lowing manner:
N
N
N
E.
i=l
where A. = the average emission factor from the ith gin
a1!" = the standard deviation of A.
The emission factors in Table 11 indicate that 62.7% of the emis-
sions from gins processing picker-harvested cotton are from the
lint-handling system. As with stripper-harvested cotton, there
is a large variation in emission factors as a result of fluctua-
ting ginning rates and varying trash contents of the seed cotton.
Picker-harvested seed cotton contains 5% to 15% trash.
30
-------
Tests were conducted at the U.S. Cotton Ginning Research Labora-
tory, Stoneville, Mississippi, over a 3-yr period to determine
both the collection efficiency and the emission particle size dis-
tribution of cyclones (19). The results indicated that a sharp
decrease in collection efficiency took place when the recommended
inlet velocity of 914 m/min was exceeded. The total collection
efficiency varied from 99.884% to 99.946% by weight, with an
average value of 99.927% by weight.
The particle size analysis of the emissions showed that 90% of
the particles emitted from the cyclone were smaller than 8 ym
(Figure 18). The coefficient of determination for the curve fit
was 0.990.
100
CD
K-i
C£
I—
CO
I—I
1=1
LU
M
»—i
GO
80
60
40
20
Y = 107.5702 - 146-9117
8 12
PARTICLE SIZE,
16
20
24
Figure 18.
Composite of accumulative particle
size distribution (19) .
One factor that affects the emissions is the maintenance of the
air pollution control equipment. Source tests on a 1.5 m skimmer
at a gin processing picker-harvested cotton found significantly
larger emissions as the unit got increasingly dirty (6) . Initial
samples from the skimmer yielded an average emission factor of
2.35 g/kg. Later resampling of the same unit under similar condi-
tions resulted in an average emission factor of 8.6 g/kg. After
the skimmer ,was dismantled and the trash lines were cleaned,
resampling indicated an average emission factor of 0.77 g/kg.
(19) Wesley, R. A., W. D. Mayfield, and 0. L. McCaskill. An
Evaluation of the Cyclone Collector for Cotton Gins. Tech-
nical Bulletin No. .1439, U.S. Department of Agriculture,
Washington, B.C., January 1972. 13 pp.
31
-------
Pesticides and Trace Elements—
Pesticide residues may accumulate on cotton plants, cotton bolls,
and topsoil. Therefore, trace quantities of these pesticides may
be found in the cotton dust and lint emitted during the ginning
process.
Samples of unprocessed picker-harvested seed cotton and trash
were collected at Gins E and F for pesticide analysis. The seed
cotton was collected at the trailer before ginning.
Trash samples were collected from the bottom discharges of the
cyclones from the green leaf and stick extractor, gin stand and
mote chamber, gravity-type cleaner, and trash house. The samples
were analyzed at the EPA Pesticides Monitoring Laboratory in Bay
St. Louis, Mississippi, under the direction of Dr. Han Tai. The
results of this analysis are given in Table 12 (20, 21).
TABLE 12. PESTICIDE ANALYSIS OF SEED COTTON AND TRASH (20, 21)
Sample concentration, ppm by wt
Compound
p,p'-DDT
O,p-DDT
p,p'-TDEa
p ,p ' -DDE
Toxaphene
DBF
Methyl parathion
Endrin
Seed
cotton
4.57
0.54
0.19
0.31
6.16
0.09
0.09
0.01
Green leaf
and stick
extractor
10.1
1
0.21
0.45
25.9
0.17
0.17
b
Trash
Gin stand
and mote
chamber
17.2
2
0.78
1
27.9
0.17
0.06
b
Gravity-
type
cleaner
53
5.94
2.60
3.91
136
0.7
0.10
b
Trash
house
19.5
3.57
2.08
1.61
22.5
b
0.33
<0.01
Minimum
detectable
limit
ppm by wt
0.01
0.01
0.01
0.01
0.1
0.05
0.05
0.01
Degradation product of DDT. No sample collected.
Pesticide emission factors are given in Table 13. They were
calculated based on the assumption that the pesticide concentra-
tion in the cyclone emissions is the same as the concentration in
(20) Feairheller, W. R., and D. L. Harris. Particulate Emission
Measurements from Cotton Gins, Delta and Pine Land Co.,
Scott, Mississippi. EMB Project Report No. 72-MM-16, U.S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, November 1974. 239 pp.
(21) Feairheller, W. R., and D. L. Harris. Particulate Emission
Measurements from Cotton Gins, Bleckley Farm Service Co.,
Cochran, Georgia. EMB Project Report No. 72-MM-23, U.S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, November 1974. 265 pp.
32
-------
TABLE 13. PESTICIDE EMISSION FACTORS
Emission factor, u
-------
TABLE 14. TRACE ELEMENT ANALYSIS OF PARTICULATE EMISSIONS
FROM THE UNLOADING FAN AT A GIN PROCESSING
MIDSEASON, PICKER-HARVESTED COTTON (21)
Concentration in dust,
Element ppm by wt
Antimony
Arsenic
Barium
Beryllium
Boron
Cadmium
Calcium
Chromium
Copper
Iron
Lead
Lithium
Magnesium
Manganese
Nickel
Potassium
Silicon
Silver
Sodium
Strontium
Tin
Vanadium
Zinc
<4,700
-------
TABLE 15. DISTRIBUTION OP GIN BATTERIES BY CAPACITY IN BALES/HR
FOR EACH STATE, REGION, AND UNITED STATES, 1970 (13)
Capacity in bales/hr
State
and
region
6
or
below
7
and
8
9
and
10
11
to
13
Number of
North Carolina
South Carolina
Georgia
Alabama
Southeast
Mississippi
Tennessee
Missouri
Arkansas
Louisiana
Mid south
Texas
Oklahoma
Southwest
New Mexico
Arizona
California
West
TOTAL
89
119
106
153
467
201
142
54
216
51
664
154
44
198
12
2
0
14
1,343
16
45
64
72
197
161
49
43
135
54
442
467
43
510
22
27
48
97
1,246
0
4
6
5
15
23
3
7
23
17
73
294
17
311
6
61
115
182
581
5
20
21
25
71
61
12
10
29
21
133
146
17
163
8
13
49
70
437
14
to
17
gin
0
5
3
8
16
22
1
1
8
4
36
71
7
78
2
3
25
30
160
18
19
to
21
22
to
25
36
Total3
batteries
1
1
3
0
5
28
1
1
8
8
46
25
3
28
0
7
8
15
94
0
0
0
1
1
1
0
0
0
2
3
10
2
12
0
0
2
2
18
0
0
0
0
0
6
0
0
2
2
10
7
0
7
0
0
10
10
27
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
111
194
203
264
772
503
208
116
421
159
1,407
1,174
133
1,307
50
113
258
421
3,907
Totals do not agree with census figures because both active gins and those
idle gins considered likely to operate again are included here.
The length of the ginning season extends from August through
January, but individual gins operate only during a small portion
of the season. Ginning periods range from 8 to 24 hr/day, 5 to
7 days/wk, and 5 to 20 wk/yr. The results of an EPA-sponsored
survey illustrating operating schedules in 1974 (Table 16) (23)
indicate that the average gin operates approximately 10 hr/day,
6 days/wk, and 10 wk/yr for a total of 600 hr/yr.
(23) LeSourd, D. , and F. K. Zada. Final Report - Capital and Oper-
ating Cost Study of Model Cotton Gin Plants with Pollution
Control Systems. RTI Project No. 41U-762-7, Research Tri-
angle Institute, Research Triangle Park, North Carolina, and
PEDCo-Environmental Specialists, Inc., Cincinnati, Ohio, May
1974. 221 pp.
35
-------
TABLE 16. NUMBER OF GINS, BY SIZE AND
NORMAL OPERATING SCHEDULE (23)
Capacity
in
bales/hr
1 to 4
5 to 9
10 to 14
15 to 19
20 to 24
25 to 29
30 to 34
TOTAL
Number
of
plants
52
151
50
17
1
1
4
276
No.
plants
built
last
5 yr
1
3
5'
0
1
1
0
11
Normal operating
Hr/day
Up
to
8
2
0
0
0
0
0
0
2
89s
to
12
36
67
18
5
0
0
1
127
12*
to
18
9
28
5
3
0
0
0
45
18*
to
23
1
3
2
2
1
0
0
9
24
2
34
18
7
0
1
2
64
schedule
Days/wk
5
or
less
5
1
2
0
0
0
0
8
5k
to
6
33
68
16
4
1 -
0
0
122
7
9
65
23
12
0
1
4
114
5 ,
or
less
5
8
1
0
0
0
0
14
- 6
to
10
17
51
19
7
1
1
2
98
Wk/yr
11
to
15
22
65
24
5
0
0
1
117
16
to
20
7
19
3
3
0
0
1
33
Over
20
1
0
0
1
0
0
0
2
This operating period and the ginning capacity of 6.8 bales/hr
yield an annual production rate of 4,080 bales/yr of cotton. In
comparison, the average production rate reported by the U.S.
Bureau of the Census for the 1976 cotton year is 3,734 bales/yr-
gin of cotton (1).
The trend in the ginning industry is toward large gins with pro-
duction capacities greater than 18 bales/hr and continuous opera-
tion for 7 days/wk, 12 to 20 wk/yr.
All cotton gins use high efficiency (greater than 99%) , small
diameter (less than 0.96 m) cyclones on all fan exhausts, except
at the lint cleaner condenser and battery condenser exhaust.
Cyclone exhausts are located 4 m to 15 m above the ground, with
an average emission height of 5.2 m.
Approximately 80% of the active gins either use or are in the
process of adding screen coverings to their condenser drums in
order to reduce emissions. These screen coverings are about 94%
efficient at collecting lint fly and particles greater than 125 ym
and 5% efficient for particles less than 125 ym, yielding a total
collection efficiency, by weight, of 36% to 42%. The remaining
gins (20%) have installed inline filters on their condenser
exhausts. These units are 99% efficient at collecting lint fly
and 70% efficient for dust, yielding a total collection efficiency
of 87% (9, 11) (personal communication, C. B. Parnell, Jr., Texas
'Agricultural Extension Service, Texas A&M University, College Sta-
tion, Texas). Inline filters and condenser exhausts are located
1.5 m to 5.0 m above the ground, with an average emission height
of 2.4 m.
Cotton dust emission factors at individual gins vary widely, from
about 0.6 g/kg to 9.5 g/kg, depending on the ginning rate and seed
cotton trash content. Evaluation of the emission factors in
Tables 9 and 11 indicates that while stripper-harvested cotton
contains relatively more trash than picker-harvested cotton, the
average total emission factors for gins handling these two types
of cotton differ by only 13.3%. Therefore, the average total
36
-------
emission factor of 3.144 ± 0.197 g/kg for typical controlled emis-
sions will be used to define a representative cotton gin. The
emission factors for each emission source within a gin are given
in Table 17. The values were calculated by averaging the appro-
priate emission factors for midseason-harvested stripper cotton
and the average values for picker cotton.
TABLE 17. EMISSION FACTORS FOR A REPRESENTATIVE COTTON GIN
Emission factor,
Emission source g/kg
Unloading fan
No. 1 dryer and cleaner
No. 2 dryer and cleaner
Trash fan for extractors
Overflow fan
No. 1 lint cleaner condenser
No. 2 lint cleaner condenser
Mote fan
Battery condenser
Master trash fan
0
0
0
0
0
0
0
0
0
0
.305
.258
.160
.027
.246
.942
.277
.262
.337
.330
+
±
±
+
+
+
+
±
±
+
0
0
0
0
0
0
0
0
0
0
.109
.042
.068
.010
.010
.087
.067
.012
.057
.067
TOTAL 3.144 ± 0.197
The masses of cotton dust emitted from gins in the 18 cotton-
ginning states are given in Table 18 (24). These values were
calculated by multiplying the average total cotton dust emission
factor (3.144 g/kg) by the quantity of cotton ginned in each
state.
The contribution of cotton dust particulate emissions to each
state's total annual particulate emissions is also shown in
Table 18. The maximum, minimum, and average gin emission contri-
butions are 0.82%, less than 0.01%, and 0.15%, respectively. On
a national basis, emissions from cotton gins in 1976 represented
0.04% of the total annual particulate emissions.
As indicated from data in Table 7, 94.2% of all cotton gins are
located in counties with fewer than 50 persons/km2. In addition,
74.7% of the counties containing cotton gins have a population
density lower than 11 persons/km2. Furthermore, 50% of the cot-
ton gins are located in counties with a population density less
than 12 persons/km2. A value of 12 persons/km2 will therefore be
used to represent the population density around a representative
gin.
(24) National Emission Report - 1972. Publication No. EPA-450/2-
74/012, U.S. Environmental Protection Agency, Washington, B.C.
June 1974. 422 pp.
37
-------
TABLE 18. MASS OF COTTON DUST EMITTED IN THE UNITED STATES
State
Alabama
Arizona
Arkansas
California
Florida
Georgia
Kentucky
Louisiana
Mississippi
Missouri
Nevada
New Mexico
North Carolina
Oklahoma
South Carolina
Tennessee
Texas
Virginia
TOTAL U.S.
Quantity Mass of
ginned emissions
in 1976, from gins,
metric tons metric tons/yr
76,450
190,092
169,769
542,735
569
42,789
569
120,866
249,923
35,203
569
15,949
16,045
38,095
31,396
49,156
722,032
569
2,302,776
240
598
534
1,706
2
135
2
380
786
110
2
50
50
120
98
155
2,270
2
7,240
Total state
particulate
emissions (24)
metric tons/yr
1,178,643
72,685
137,817
1,006,452 ,
226,460
404,574
546,214
380,551
168,355
202,435
94,040
102,785
481,017
93,595
198,767
409,704
549,399
477,794
17,872,000
Contribution
from gins , %
0.02
0.82
0.39
0.17
<0.01
0.03
<0.01
0.10
0.47
0.05
<0.01
0.05
0.01
0.13
0.05
0.04
0.41
<0.01
0.04
Based on a representative gin emission factor of 3.144 g/kg.
EFFECT ON AIR QUALITY
In order to determine the effect of cotton gin emissions on air
quality, the source severity, S, is defined as:
S =
(1)
where
xmax = a time~wei<3nted' 24-hour average of the maximum
downwind ground level concentration of the emission
species
F = TLV (8/24) (1/100)
(2)
where
TLV = threshold limit values for the emission species
8/24 = normalizes the factor to a 24-hr/day exposure
1/100 = safety factor
For criteria pollutants, the 24-hr primary ambient air standard
is substituted for F.
38
-------
The value of xmax is calculated from the following equation (25):
xmax xmax\t / (3)
where xmax = maximum ground level concentration of the emission
species (calculated from Equation 4)
to = short-term averaging time
t = averaging time
= 2 Q
^max
where Q = emission rate, g/s
TT = 3.14
e = 2.72
u = average wind speed, m/s
h = stack height, m
The equation for Xmax (Equation 4) is derived from the general
plume dispersion equation for an elevated source and gives the
ground level concentration directly downwind from the source under
U.S. average atmospheric stability conditions (25). A wind speed
of 4.5 m/s is used for u.
For a 24-hr time-weighted ground level concentration, the values
of time for t and t (Equation 3) are 3 min and 1,440 min, respec-
tively. Therefore, Equation 3 reduces to:
= Xmax(T7140)°"17 = (0.35)Xmax (5)
Values of x anc* S for representative cotton gins emitting cot-
ton dust areashown in Table 19, based on the TLV for cotton dust
of 0.2 mg/m3 (16). A representative gin is defined as producing
4,080 bales/yr (888 metric tons/yr), operating 600 hr/yr, and
having a total emission factor of 3.144 ± 0.395 g/kg. The value
of S for each possible pesticide emission (Table 13) was less
than 0.01.
Because of low emission heights (5.2 m for cyclones and 2.4 m for
inline filters), the values of Ymax occur within 25 m of the
source. This distance is well within the property lines of a typi-
cal gin. The Handbook for Cotton Ginners (4) recommends a gin
yard design of 305 m x 427 m for minimum safe distances between
buildings for fire protection. The radius of a circle of equal
(25) Turner, D. B. Workbook of Atmospheric Dispersion Estimates.
Publication No. 999-AP-26, U.S. Department of Health, Educa-
tion, and Welfare, Public Health Service, Cincinnati, Ohio,
May 1970. 84 pp.
39
-------
TABLE 19. SOURCE SEVERITY FOR CONTROLLED COTTON DUST
EMISSIONS FROM A REPRESENTATIVE COTTON GIN
Emission source
Unloading fan
No. 1 dryer and cleaner
No. 2 dryer and cleaner
Trash fan for extractors
Overflow fan
No. 1 lint cleaner condenser
No. 2 lint cleaner condens'er
Mote fan
Battery condenser
Master trash fan
Stack
height ,
m
5.2
5.2
5.2
5.2
5.2
2.4
2.4
5.2
2.4
16
At
—
xmax'
Ug/m3
84.4
71.4
44.3
7.5
68.1
122.4
36
72.5
43.8
9.6
Xmax
Source
severity,
S
127
107
66
11
102
184
54
109
66
14
At property line
—
Xmax'
yg/m3
8.3
6.9
4.3
0.7
6.6
26.6
7.8
7
9.5
<0.01
1 Source
severity ,
S
12
10
6
1
10
40
12
10
14
<0.01
a.
Property line 204 m from source.
area for this gin yard is 204 m. Therefore, the ground level cot-
ton dust concentration at the property line (204 m from the
source) , calculated from the general plume dispersion equation
(25), is used for x (and x_ax) • The values of 7 and the
corresponding values 8f S are also given in Table 1
Another measure of the potential environmental impact is the popu-
lation that may be affected by emissions from a typical cotton
gin. The affected population is defined as the number of persons
living in the area around a gin where the time-averaged ground
level concentration (-y) divided by F is greater than 1.0. Because
the compactness of cotton-ginning operations at a gin, the total
emission factor of 3.144 g/kg and the dominant stack height of
5.2m were used to calculate the affected population. Plume
dispersion calculations show the two locations downwind from the
gin where x/F exceeds 1.0 (Figure 19). For x/F greater than or
equal to 1.0, the values of xx and x2 are 12 m and 4,113 m.
Since a gin is located a distance of 204 m from the gin property
line, the resulting area circumscribed by the annulus from 204 m
to 4,113 m gives an affected population of 576 persons based on
an average population density of 12 persons/km2 .
Figure 19.
x, x2
DISTANCE FROM SOURCE
General distribution of x/F as a function
of distance from the source, showing the two
general roots to the plume dispersion equation,
40
-------
SECTION 5
CONTROL TECHNOLOGY
STATE OF THE ART
Numerous devices are used at cotton gins to reduce particulate
emissions. Air pollution control equipment currently employed
includes cyclones, filters, and wet scrubbers.
Cyclones
The cyclone is used at all cotton gins to collect dust and trash
from the conveying air and to reduce particulate emissions (26).
The number of cyclones recommended for a gin ranges from 10 for
a 6-bale/hr gin processing picker-harvested cotten to 24 for a
36-bale/hr gin processing stripper-harvested cotton (13). More
cyclones are required for a gin processing stripper-harvested
cotton because of the relatively high quantities of trash in
the stripper cotton.
The majority (greater than 90%) of the cyclones used at gins are
the small-diameter (less than 0.96 m), high-efficiency (greater
than 99% for particles greater than 125 ym) type developed by the
Atomic Energy Commission (13). Relative dimensions for this type
of cyclone are critical for satisfactory operation (Figure 20).
An 0.86-m diameter has been recommended as the optimum for high
efficiency cyclones (13). In addition, the air inlet velocity
must be approximately 914 m/min, and the air volume must not
exceed 85 m3/min (4). The back pressure for these cyclones
ranges from 996 Pa to 1,245 Pa (4 in. to 5 in. of water). The
calculated pressure drop for cyclones designed for an inlet
velocity of 914 m/min is 1,071 Pa (4.3 in. of water) (13).
When the volume of air exceeds 84 to 130 m3/min, two or more
cyclones are used in parallel. Cyclone banks consists of a single,
double, or quadruple arrangement of cyclones. Single cyclones
handle up to 85 m3/min, double cyclones handle up to 170 m3/min,
and quadruple cyclone sets handle up to 311 m3/min.
(26) Moore, V. P., and 0. L. McCaskill. Evaluation of Abatement
Methods Applicable to Cotton Gins. In: Industrial Air
Pollution Control, Noll, K. E., and J. R. Duncan (eds.).
Ann Arbor Science Publishers, Inc., Ann Arbor, Michigan,
1974. pp. 229-240.
41
-------
J
ORT1
<
[ONS
H
C
•^^
-><_^
" "~ "" "
h-DEH
]
— 0^ — -
Figure 20.
Br = Dr/4
u v,
Hc = Dc/2
D£ - Dc/2
LC = 2DC
sc = Dc/8
ZC = 2DC
Jr = 0.3 m MINIMUM
Relative dimensions for a small-diameter,
(<96 m) high-efficiency (>99%) cyclone (13)
Tests were conducted in 1972 at the U.S. Cotton Ginning Labora-
tory, Stoneville, Mississippi, to determine the collection effi-
ciency of the small-diameter (less than 0.96 m) , high-efficiency
(greater than 99% for particles less than 125 pm) cyclone (19) .
The cyclone was designed according to Figure 20 with a 0.41-m
diameter and an inlet velocity of 914 m/min. The results showed
that there was a sharp decrease in collection , efficiency when the
recommended inlet velocity of 914 m/min was exceeded. The total
collection efficiency varied from 99.884% to 99.946% by weight.
A composite of all data indicated that the cyclone operated at an
average collection efficiency of 99.927% by weight.
Earlier reports indicate that for a small-diameter cyclone with a
0.76-m diameter, the total particulate collection efficiency was
99.94% by weight on large trash removed from stripper-harvested
cotton when the cyclone operated with an inlet velocity of
approximately 914 m/min (8) . Other source test data measured
cyclone particulate collection efficiencies ranging from 83% to
99.9% by weight (21) .
Filters
Filters are installed at about 20% of gins, nationwide, to collect
lint fly and small amounts of dust on low-pressure, high-volume air
42
-------
discharges following condensers. These filters may be of a fixed-
screen or revolving-screen design. Essentially, a filter of this
type consists of a fine mesh filtering screen mounted in an
enclosed housing. The screen may be of stainless steel or Monel
bolting cloth with about 50% open area. Foreign matter such as
lint fly and leaf trash accumulates on the screen surface during
the collection sequence and acts as a filter to catch finer dust
particles.
Three basic types of inline filters are used at cotton gins. The
first design, developed in 1964, is a fixed concave screen inline
air filter with a revolving wiping brush (Figure 21) (27). The
dust and lint-laden air passes into the filter screen. When the
back pressure of the unit reaches a preset level, a motor is
activated that causes the brush to revolve and clean the screen.
WIPING BRUSH
FINE MESH FILTERING SCREEN
DUST & LINT-
LADEN AIR
CLEAN AIR
Figure 21.
Fixed-screen inline filter with
revolving wiping brush (13).
The second type of inline filter is similar in design to the
first, except that it uses a screen-covered revolving drum with a
fixed wiping brush (Figure 22) (13).
A new, simpler design is a round inline filter with a fixed,
flat (horizontal) screen and a radial wiping arm (Figure 23) (28).
This filter is less expensive than the others because it requires
no scaffolding and is easier to construct. In comparative tests,
(27) Alberson, D. M., and R. V. Baker. An Inline Air Filter for
Collecting Cotton Gin Condenser Air Pollutants. Publication
No. ARS 42-103, U.S. Department of Agriculture, Washington,
B.C., September 1964. 16 pp.
(28) Parnell, C. B., Jr., and R. V. Baker. Application and
Design of Round Air Filters for Axial-Flow Fan Exhausts of
Cotton Gins. In: Proceedings of First Annual Symposium on
Air Pollution Control in the Southwest, Cooper, H. B. H.,
Jr., and J. M. Hughes (eds.)., Texas A&M University, College
Station, Texas, November 1973. pp. 168-188.
43
-------
DUST & LINT-
LADEN AIR
WIPING BRUSH
CYLINDER
SCREEN
COVERED.
REVOLVING
DRUM
CLEAN AIR
Figure 22.
Revolving-screen inline filter
with fixed wiping brush (13).
WIPING ARM
CLEAN AIR
ROUND AIR FILTER
DUST & LINT
Figure 23.
Horizontal-round inline filter
with radial wiping arm (13).
all three types of filters had collection efficiencies of about
99% for lint fly and overall collection efficiencies of 80% on
stripper-harvested cotton.
Studies at the USDA Ginning Research Laboratory indicate that
lint fly emissions can also be reduced by covering the condenser
drum with fine screen wire (0.5-mm to 1.9-mm openings), as shown
in Figure 24 (13). This design reduced the lint fly and dust con-
centration in the exhaust air from 0.12 to 0.05 g/m3 when the
drum was covered with 70-mesh (210-ym openings) cloth. When the
condenser was covered with perforated metal having 8.4-mm diam-
eter openings and a 20% open area in lieu of the conventional
covering material, the dust concentration was reduced from
0.12 g/m3 to 0.07 g/m3 of exhaust air (26).
44
-------
FINE SCREEN OVER STANDARD DRUM
OR
FINE PERFORATED METAL
STANDARD DRUM COVERING
Figure 24. Standard condenser drum covering overlaid with
fine screen or fine perforated metal (13).
Approximately 80% of the country's active gins either use covered
condensers or are installing them in order to reduce lint fly
emissions (personal communication, C. B. Pernell, Jr., Texas
Agricultural Extension Service, Texas A&M University, College
Station, Texas). Covering a condenser drum costs about $300,
whereas installed inline filters cost about $2,000 each.
Wet Scrubbers
To date, less than five cotton gins use wet scrubbers. The J. G-
Boswell Company Gin, El Rico 19, uses air/water spray scrubbing
chambers on the exhaust outlets of the battery condensers and on
the exhaust from all six lint cleaners. Two skimmer-spray column
combinations are used to control the exhaust emissions from the
two inclined cleaners, two overflow separators, two moisture-
conditioning hoppers, and the extractor feeders.
Results of source test data at this gin found that the particu-
late collection efficiency of the lint cleaner wet scrubber
ranged from 74.1% to 96.2%, with an average value of 83% by
weight (5). The skimmer and spray column combinations yielded
collection efficiencies ranging from 98.3% to 99.8%, with an
average value of 99.1% by weight.
Cost Overview
Recent studies have evaluated the economic impact of retrofitting
cotton gins with air pollution control equipment. Estimates for
the cost of installing small-diameter, high-efficiency cyclones
and inline air filters, plus the cost of overhead storage hoppers
and trucks for hauling trash, range from about $24,000 for a 6-
bale/hr gin designed for machine-picked cotton to over $53,000
for a plant capable of ginning 36 bales of stripper-harvested
cotton/hr (13).
45
-------
If all active gins in the United States were compelled to install
cyclones on all fan exhausts, inline filters on all condenser
exhausts, and a secondary collection system, and haul the accum-
ulated trash to an approved site away from the plant, the re-
sulting total investment would exceed $100 million (13). Annual
costs under these conditions, including depreciation, interest,
taxes, insurance, maintenance, extra energy, and hauling expenses,
would exceed $28.5 million. This amounts to about $2.33/bale,
based on a 12.8 x 106-bale crop.
The purpose of a second study was to develop capital and operating
costs for three model cotton gins (23), including costs for three
alternative pollution control systems and their impact on the
ginning cost. A summary of these cost data is given in Table 20.
The assumptions used to derive the cost values are listed in
Table 21. The cost of retrofitting these three gins ranges from
$0.47 to $2.37/bale (13).
FUTURE CONSIDERATIONS
The installation of small-diameter, high-efficiency cyclones on
all exhaust high pressure fans and of inline filters on low pres-
sure condenser exhausts would reduce particulate emissions from
cotton gins. Maintenance of the cyclones and inline air filters
is a major factor affecting the performance of each device. Each
gin should take extra precautions to insure that the cyclone
discharge lines do not clog. Further work on the design of
cyclone discharge systems would help to control emissions.
Source test data indicate that field extraction of trash can
reduce emissions by 1% to 35% (11). This procedure is not widely
practiced to date.
Other suggestions for reducing emissions from gins include:
1) operate cyclones only at their design capacities and install
additional cyclones if the present ones are overloaded, 2) insure
that the machine harvesting equipment is properly adjusted so
that it does not pick up soil in the harvesting process, and
3) shelter the trash hopper system when the hopper dumps into the
hauling truck.
46
-------
TABLE 20. SUMMARY OF COST DATA FOR MODEL COTTON GIN PLANTS
Cost factor
Model Plant A, 10 bales/hr :
Capital cost
Ginning cost/yr
Ginning cost/bale
Cost of controls/bale
Model Plant B, 24 bales/hr:
Capital cost
Ginning cost/yr
Ginning cost/bale
Cost of controls/bale
Without pollution
control systems
$339,788
157,592
25.02
517,086
377,578
14.98
With pollution control systems
Ia
$ 360,265
162,852
25.84
0.82
550,674
389,301
15.45
0.47
IIb
$ 384,584
168,875
26.80
1.78
612,069
40-6,459
16.13
1.15
IIIC
$ 426,497
176,838
28.07
3.05
669,424
416,348
16.52
1.54
Model Plant C, 40 bales/hr:
Capital
Ginning
Ginning
Cost of
cost
cost/yr
cost/bale
controls/bale
978,044
522,990
16.14
1,025,558
538,671
16.62
0.48
1,114,180
561,168
17.32
1.18
1,183,726
599,654
18.51
2.37
With high-efficiency cyclones and inline filters.
With high-efficiency cyclones and wet scrubbers.
With baghouses.
TABLE 21. DESIGN BASIS FOR MODEL COTTON GIN PLANTS (23)
Location
Type of cotton ginned
Method of harvesting
Density of bale of ginned cotton
Rated capacities:
Model Plant A
Model Plant B
Model Plant C
Equipment utilization factor8
Operating schedule:
Model Plant A
Model Plant B
Model Plant C
Plant costs
Operating costs
Supervisionuand labor:
Maintenance
Utili'tiesb
Bags and ties
Trash disposal
Interest on borrowed capital
Depreciation**
Property tax
Insurance
Pollution control systems:
System I
System II
System in
Ginning costs
Southeastern-South Central region of the United states
Upland cotton
Machine picked
224 kg/m3
Ten 227-kg bales of cotton/hr
Twenty-four 227-kg bales of cotton/hr
Forty 227-kg bales of cotton/hr
75%
One 12-hr shift, 7 days/wk, 70 days/yr
Two 10-hr shifts, 7 days/wk, 70 days/yr
Two 12-hr shifts, 7 days/wk, 45 days/yr
Based on proposals prepared by manufacturers of cotton gin equipment
Industry*s practices and wage structure
Industry's average $/bale
Industry's average $/bale
Industry's average $/bale
Based on $4.4/metric ton ($4/ton) of trash
Based on 7% interest rate
Industry's allowable depreciation rates
Assumed 2% of capital investment
Assumed 1% of capital investment
High-efficiency (small-diameter) cyclones on high-pressure system
and inline filters on low-pressure system
High-efficiency (small-diameter) cyclones on high-pressure system
and wet scrubbers on low-pressure system
Baghouses (fabric filters)
For the purpose of this study, costs of hauling in the seed cotton,
hauling out the seeds and the ginned cotton, and warehousing are
not considered as part of the ginning operation but as related
services for which separate charges are levied.
aDefined as the average hourly production rates during the ginning season, divided by the hourly rated
capacity of the gin. plant.
bBased on figures obtained from cotton gin equipment manufacturer.
CEstimate based on figures from "What We Know About Pollution Control." Published by Texas Cotton
Ginners Association.
dBased on figures obtained from cotton gin equipment manufacturer.
47
-------
SECTION 6
GROWTH AND NATURE OF THE INDUSTRY
PRESENT TECHNOLOGY
There is very little variation in the equipment used at different
cotton gins. The primary difference is in the placement of equip-
ment and duct work. For example, one gin may include the trash
from the gin stands with the trash from the extractors. Other
gins may include the gin-stand trash with that from the conden-
sers or mote fan. Additionally, some (less than 30%) gins employ
three seed-cotton cleaning stages instead of two.
A smaller difference in process description is in the amount of
air required to process stripper-harvested cotton as opposed to
picker-harvested. Gins processing stripper-harvested cotton
require about 20% more air because of the higher trash content in
the seed cotton (13).
EMERGING TECHNOLOGY
Because of regulations in the 1970 Clean Air Act, all ginning
states have banned the incineration of gin trash. Gins now must
have trash houses where the trash is stored until enough accumu-
lates to fill a truck. During the ginning season, the trash
house is emptied from one to four times daily, and extra precau-
tions must be taken to insure that this dumping of the trash bin
does not become another source of particulate emissions.
The Occupational Safety and Health Administration is requiring
gins to reduce the amount of suspended particulate matter in the
rooms of the gin to 1.0 mg/m3 (29). This ruling means that room
ventilation systems will be installed, thus requiring more
cyclones or inline filters.
The most significant trend in the ginning industry is to fewer,
larger gins (13). While cotton acreage and the production have
been declining generally, the older, low-capacity (6 bales/hr)
gins are being replaced by higher-capacity (greater than
(29) General Industrial Occupational Safety and Health Standards.
29 CFR 1910.1000, U.S. Department of Labor, Occupational
Safety and Health Administration, Washington, D.C., January
1976.
48
-------
10 bales/hr) plants. The trend to fewer plants could be acceler-
ated by imposed air pollution control regulations. The cost of
installing additional air pollution control devices is prohibi-
tive for low-volume, older gins.
INDUSTRY PRODUCTION TRENDS
As previously mentioned, there is a slow downward trend in the
production of cotton. As illustrated in Figure 25, there is a
wide fluctuation in the amount of cotton ginned from year to year
because of fiber demand and weather conditions.
15
S 10
o
o
ce.
o_
PROJECTED
1960
1965
1970 1975
CROP YEAR
1980
1985
Figure 25. Trend in cotton production (1).
In addition, there is a definite decrease in the number of active
cotton gins (Figure 26). The trend is toward fewer, but larger
capacity, continuous gins.
6,000
5,000
LJLJ
p 4,000
o
3,000
2,000
1,000
0
l/)
O
-------
SECTION 7
UNUSUAL RESULTS
Emissions from the incineration of gin trash (sticks, stems,
leaves, burrs, and dirt) are discussed separately because it is a
practice that is rapidly being phased out. Before the 1970 Clean
Air Act, a large portion (more than 35%) of the gins disposed of
gin trash by open burning or by incineration in teepee burners
(12). These incineration methods are relatively inefficient and
result in plumes with an opacity reading more than 40% and numer-
ous complaints from residents near the gin. After the passage of
the Act and its amendments, open burning of gin trash was outlawed
in all ginning states except Arkansas and in certain isolated
areas in west Texas having high incidence of Verticillium Wilt
(Table 22).
State air pollution control regulations also limited the opacity
of the plume from teepee burners and other incinerators to Ringel-
mann 1 or 2, depending on the state. This requirement is virtu-
ally impossible for teepee burners to meet, and the majority of
such burners were subsequently shut down.
Table 22 indicates that less than 133 gins are still allowed to
use teepee burners. In the states of Alabama, Arkansas, and
Louisiana, the state air pollution control authorities have
granted compliance variances and allowed gins to use teepee
burners. However, plans are being formulated by these states to
phase out these incinerators in the next 2 to 5 years.
In all cotton ginning states, incineration of gin trash is per-
mitted provided that it is carried out in multiple chamber incin-
erators and that the emissions meet the state standards. Few
(less than 10) gins are equipped with this type of incinerator
because of the higher capital cost as compared to land disposal
methods. However, these gins are experimenting with recovering
the heat from these incinerators and using it to dry the seed
cotton. This concept would reduce natural gas fuel costs, thus
reducing the cost of the incinerator. Safety problems associated
with the air-to-air heat exchanger and in choosing the proper
design characteristics have slowed down industrial acceptance of
this concept.
Because a few teepee burners are still in use, emission factors
are developed in this section. A teepee burner or incinerator,
shown schematically in Figure 27, is a conical-shaped steel shell
50
-------
TABLE 22. SUMMARY OF AIR POLLUTION REGULATIONS
CONCERNING INCINERATION OF GIN TRASH
Open Number of gins
burning using
State permitted teepee burners
Alabama
Arizona
Arkansas
California
Georgia
Louisiana
Mississippi
New Mexico
North Carolina
Oklahoma
South Carolina
Tennessee
Texas
No
No
Yes
No
No
No
No
No
No
No
No
Nod
No°
<20
0
66
0
if*
45D
0
o
1C
0
0
0
0
Approved by Georgia Environmental Protection Division.
Granted a variance to burn by Louisiana Air Control
Division.
r*>
"Meets all North Carolina emissions regulations.
Open burning temporarily permitted in certain areas
of west Texas with high incidence of Verticillium Wilt.
TRASH
FROM-
GIN
•=nCYCLONE EXIT GAS
\J
SURGE
BIN
FAN
—^
UNDERFIREAIR
Figure 27. Optimum design teepee incinerator,
51
-------
with the base diameter approximately equal to the height and
topped with a dome-shaped, spark-arrester screen. Cotton gin
trash is pneumatically conveyed to a cyclone where the trash is
separated from the air stream. The trash falls either directly
into the incinerator or first into a surge bin where it is dis-
charged at a controlled rate into the incinerator.
Several teepee modifications have been suggested to reduce smoke
and air emissions. Some of these modifications include radial
forced air injection, continuous feeding, the elimination of as
many openings and cracks as possible, adequate but controlled
underfire air supply, damper at the top, and maintenance of an
exit gas temperature between 370°C and 480°C regulating air flow
rate (30, 31). The most critical of these factors appears to be
the level of maintenance on the incinerator. It is not uncommon
for teepee burners to have missing doors and numerous holes in the
shell, which result in excessive combustion air, low burning
temperatures, and, therefore, higher emission rates of combustible
pollutants.
No stack test data are reported in the literature for emissions
from teepee burners at cotton gins. However, several stack tests
have been conducted on teepee burners burning wood waste. The
emission factors shown in Table 23 are a result of extensive
tests made on a well-maintained teepee burner at Forest Research
Laboratory at Oregon State University burning wood waste (30).
The emission factors shown should represent best case values for
teepee burners at cotton gins. Hydrocarbon emission species
include polynuclear hydrocarbons such as benzo(a)pyrene, pyrene,
perylene, anthanthrene, and fluoranthene. Emissions of pesti-
cides, defoliants, and dessicants can also be expected if these
materials have been applied to the cotton.
Using the emission factors in Table 23, the source severity and
values of x" can be calculated for a typical cotton gin. Since
only gins tna£ process picker-harvested cotton are allowed to
incinerate their waste, the average trash generation rate of
90 kg/bale will be used to calculate trash quantities. The values
of x" and S are given in Table 24 for a stack height of 10 m.
TUcLX
The mass of emissions from teepee burners in those states still
allowing, the practice are given in Table 25.
(30) Kim, B. C., R. B. Engdahl, E. J. Merzey, and R. B. Landrigan.
Preliminary Report on Screening Study for Background Informa-
tion and Significant Emissions from Major Incineration
Sources. Batelle, Columbus Laboratory, Columbus, Ohio,
May 25, 1973. pp. 74-98.
(31) Kreichelt, T. E. Air Pollution Aspects of Teepee Burners
Used for Disposal of Municipal Refuse. Publication No. 999-
AP-28, U.S. Department of Health, Education, and Welfare, Pub-
lic Health Service, Cincinnati, Ohio, September 1966. 35 pp.
52
-------
TABLE 23. EMISSION FACTORS FOR A TEEPEE
BURNER BURNING WOOD WASTE (30)
Exit gas
temperature, °C
200
425
Emission factor, g/kg of waste charged
Particulate CO
8 (3.
2 (0.
5)b 30
5) 10 (65)
Hydrocarbons
2.3
0.3 (5.5)
}Based on a wood waste with a moisture content of 50%.
Data in parentheses are those given in Reference 32.
TABLE 24. ESTIMATED SOURCE SEVERITY AND Xmax FOR EMISSIONS
FROM A TEEPEE BURNER AT A TYPICAL COTTON GIN
Exit gas
—
, 9
y . uq/mv>
temperature, Amax
°C
200
425
Particulate
250
60
CO
930
310
Hydrocarbon
70
9
Source severity, S
Particulate
1.2
0.3
CO
0.02
0.008
Hydrocarbon
0.4
0.06
TABLE 25. ANNUAL MASS OF EMISSIONS FROM TEEPEE BURNERS
For exit gas
State temperature, °C
Alabama
Arkansas
Louisiana
200
425
200
425
200
425
Mass of emissions, metric tons/yr
Particulate
47
12
155
39
106
26
CO Hydrocarbons
176
59
582
194
397
132
14
2
45
6
30
4
(32) Compilation of Air Pollution Emission Factors, Second Edition,
Publication No. AP-42, U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina, April 1973.
pp. 2.3-1 to 2.3-3.
53
-------
REFERENCES
1. Cotton Ginning in the United States, Crop of 1976. U.S.
Department of Commerce, Bureau of the Census, Washington,
B.C., June 1977. 19 pp.
2. Texas Cotton Review, 1973-74. The University of Texas,
Natural Fiber Economic Research. Research Report No. NFFPC-
NFER-UT-104-74 (PB 235 388), Austin, Texas, July 1974.
143 pp.
3. Pendleton, A. M. , and V. P. Moore. Ginning Cotton to Pre-
serve Fiber Quality. Publication No. E§C-560. U.S. Depart-
ment of Agriculture, Federal Extension Service, Washington,
D.C., September 1967. 19 pp.
4. Handbook for Cotton Ginners. Agriculture Handbook No. 260.
U.S. Department of Agriculture, Agriculture Research Service,
Washington, D.C., February 1964. 121 pp.
5. Feairheller, W. R. , and D. L. Harris. Particulate Emission
Measurements from Cotton Gins, J. G. Boswell Co., El Rico #9,
Corcoran, California. EMB Project Report No. 72-MM-19, U.S.
Environmental Protection Agency, November 1974. 424 pp.
6. Survey of Particulate Emissions, Frisby-Bell Cotton Gin,
LaVilla, Texas, April 1 to August 31, 1971. Texas Air Con-
trol Board, Austin, Texas, September 1971. 31 pp.
7. Durrenberger , C. Cotton Gin Report. Texas Air Control
Board, Austin, Texas, May 31, 1974. 50 pp.
8. Baker, R. V., and V. L. Stedronsky. Gin Trash Collection
Efficiency of Small Diameter Cyclones. Publication No. ARS
42-133, U.S. Department of Agriculture, Washington, D.C.,
July 1967. 16 pp.
9. McCaskill, D. L., and R. A. Wesley. Tests Conducted on
Exhausts of Gins Handling Machine Picked Cotton. The Cotton
Gin and Oil Mill Press. September 5, 1970. 12 pp.
10. Criteria for a Recommended Standard - Occupational Exposure
to Cotton Dust. Publication No. (NIOSH) 75-118 ;, U.S. Depart-
ment of Health, Education, and Welfare, Washington, D.C. ,
1974. 159 pp.
54
-------
11. Parnell, C. B., Jr., and R. v. Baker. Particulate Emissions
of a Cotton Gin in the Texas Stripper Area. Production
Research Report No. 149, U.S. Department of Agriculture,
Agricultural Research Service, Washington, D.C., May 1973.
18 pp.
12. Pendleton, A. M. Current Gin Trash Disposal Practices. In:
Control and Disposal of Cotton-Ginning Wastes. Publication
No. 999-AP-31, U.S. Department of Health, Education, and
Welfare, Public Health Service, Cincinnati, Ohio, 1967.
pp. 39-44.
13. Wilmot, C. A., Z. M. Looney, and 0. L. McCaskill. The Cost
of Air Pollution Control to Cotton Ginners. Publication
No. ERS-536, U.S. Department of Agriculture, Economic
Research Service, Washington, D.C., February 1974. 35 pp.
14. Andrilenas, P. A. Farmer's Use of Pesticides in 1971. . .
Quantities. Agricultural Economic Report No- 252,
U.S. Department of Agriculture, Economic Research Service,
Washington, D.C., July 1974. 56 pp.
15. Gibney, L. EPA Seeks Substitutes for Banned Pesticides.
Chemical and Engineering News, 53(23)15-16, June 9, 1975.
16. TLVS® Threshold Limit Values for Chemical Substances and
Physical Agents in the Workroom Environment with Intended
Changes for 1976. American Conference of Governmental
Industrial Hygienists, Cincinnati, Ohio, 1976. 94 pp.
17. Sax, N. I. Dangerous Properties of Industrial Materials,
Third Edition. Reinhold Book Corp., New York, New York,
1968. p. 591.
18. Taylor, M., M. Preusse, D. Johnson, and R. Wallis. Particu-
late Survey of Cotton Gin Operations, Lubbock and Lubbock
County, December 1971-January 1972. Texas State Department
of Health, Air Pollution Control Services, Austin, Texas,
December 1972. 19 pp.
19. Wesley, R. A., W. D. Mayfield, and 0. L. McCaskill. An
Evaluation of the Cyclone Collector' for Cotton Gins. Tech-
nical Bulletin No. 1439, U.S. Department of Agriculture,
Washington, D.C., January 1972. 13 pp.
20. Feairheller, W. R., and D. L. Harris. Particulate Emission
Measurements from Cotton Gins, Delta and Pine Land Co.,
Scott, Mississippi. EMB Project Report No. 72-MM-16,
U.S. Environmental Protection Agency, Research Triangle Park,
North Carolina, November 1974. 239 pp.
55
-------
21. Feairheller, W. R., and D. L. Harris. Particulate Emission
Measurements from Cotton Gins, Bleckley Farm Service Co.,
Cochran, Georgia. EMB Project Report No. 72-MM-23, U.S. Envi-
ronmental Protection Agency, Research Triangle Park, North
Carolina, November 1974. 265 pp.
22. Cuffe, S. T. , and J. C. Knudson. Considerations for Deter-
mining Acceptable Ambient and Source Concentrations for
Particulates from Cotton Gins. In: Control and Disposal of
Cotton-Ginning Wastes. Publication No. 999-AP-31,
U.S. Department of Health, Education, and Welfare, Public
Health Service, Cincinnati, Ohio, 1967. pp. 79-90.
23. LeSourd, D., and F. K. Zada. Final Report - Capital and
Operating Cost Study of Model Cotton Gin Plants with Pollu-
tion Control Systems. RTI Project No. 41U-762-7, Research
Triangle Institute, Research Triangle Park, North Carolina,
and PEDCo-Environmental Specialists, Inc., Cincinnati, Ohio,
May 1974. 221 pp.
24. National Emission Report - 1972. Publication No. EPA-450/2-
74/012, U.S. Environmental Protection Agency, Washington, D.C.,
June 1974. 422 pp.
25. Turner, D. B. Workbook of Atmospheric Dispersion Estimates.
Publication No. 999-AP-26, U.S. Department of Health, Educa-
tion, and Welfare, Public Health Service, Cincinnati, Ohio,
May 1970. 84 pp.
26. Moore, V. P., and 0. L. McCaskill. Evaluation of Abatement
Methods Applicable to Cotton Gins. In: Industrial Air Pol-
lution Control, Noll, K. E., and J. R. Duncan (eds.). Ann
Arbor Science Publishers, Inc., Ann Arbor, Michigan, 1974.
pp. 229-240.
27. Alberson, D. M., and R. V. Baker. An Inline Air Filter for
Collecting Cotton Gin Condenser Air Pollutants. Publication
No. ARS 42-103, U.S. Department of Agriculture, Washington,
D.C., September 1964. ,16 pp.
28. Parnell, C. B., Jr., and R. V. Baker. Application and Design
of Round Air Filters for Axial-Flow Fan Exhausts of Cotton
Gins. In: Proceedings of First Annual Symposium on Air
Pollution Control in the Southwest, Cooper, Jr., H. B. H.,
and J. M. Hughes (eds.)., Texas A&M University, College Sta-
tion, Texas, November 1973. pp. 168-188.
29. General Industrial Occupational Safety and Health Standards.
29 CFR 1910.1000, U.S. Department of Labor, Occupational
Safety and Health Administration, Washington, D.C., January
1976.
56
-------
30. Kim, B. C., R. B. Engdahl, E. J. Merzey, and R. B. Landrigan.
Preliminary Report on Screening Study for Background Informa-
tion and Significant Emissions from Major Incineration
Sources. Batelle, Columbus Laboratory, Columbus, Ohio,
May 25, 1973. pp. 74-98.
31. Kreichelt, T. E. Air Pollution Aspects of Teepee Burners
Used for Disposal of Municipal Refuse. Publication No. 999-
AP-28, U.S. Department of Health, Education, and Welfare, Pub-
lic Health Service, Cincinnati, Ohio, September 1966. 35 pp.
32. Compilation of Air Pollution Emission Factors, Second Edition.
Publication No. AP-42, U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina, April 1973.
pp. 2.3-1 to 2.3-3.
57
-------
APPENDIX
DATA USED TO CALCULATE COTTON DUST EMISSION FACTORS
This appendix presents the raw data used to establish the emis-
sion factors given in Section 4 and describes the six cotton gins
where the source test data were collected.
GIN A
The particulate emission factors for a gin processing stripper-
harvested cotton were obtained from source test data collected
during the 1970 crop year at the USDA South Plains Cotton Ginning
Research Laboratory, Lubbock, Texas (11). Figure A-l is a flow
diagram of the ginning process showing the 10 sampling locations
(exhausts). The source tests were made to determine the total
particulate emission rates, to obtain estimates of emission rates
for field extracted and nonfield extracted cottons, and to evalu-
ate the effects of different feed rates on the emission rates.
A switch relay system was designed into the sampling system so
that all exhausts could be sampled simultaneously and only when
the air emitted had been used to actively convey material within
the ginning system. In order to sample under isokinetic condi-
tions, ductwork was attached to the top of each elevated cyclone,
connected to an inverted U-shaped duct, and extended down to
ground level, the shape resembling a candy cane. High-volume
samplers with voltage transformers (to control the sampling flow
rate) and inclined glass manometers were used to sample each
exhaust.
Approximately 1,100 glass fiber filters were used to collect
samples. All data not falling within plus or minus three standard
deviations were rejected before calculating the final average
and standard deviations. It was assumed that there was an exter-
nal error associated with any value outside this range.
The emission factors calculated from this set of source test data
were presented in Table 9 (Section 4). Emission tests were con-
ducted for cotton harvested during four periods; early season
(first week in November), midseason (mid-November), late season
(late November), and extremely dirty cotton (late November). The
extremely dirty cotton was the result of an improperly adjusted
mechanical stripper that collected loose soil along with the
cotton.
58
-------
SEED
COTTON
UNLOADING
SYSTEM
UNLOADING SYSTEM
i
y 'ft * £
AIRLINE CLEANER —*---
u
EXHAUST-
SEED COTTON
CLEANING
SYSTEM
OVERFLOW SYSTEM
nvrr?n c\\\\ ^^_^_
OVERFLOW SEPARATOR —
1 , .*-.•.
r *-'•'•• -f-
LINT COTTON
HANDLING
SYSTEM
I
*,.,. NO. 1
W I
S- ,>;>" X
.» "^ <£'-L V
''•$••• BUR h
SJ
• ; <*-,• '^« V
l!x(: NO. 2
""""4 :
STICK
f 4
— * GIN ST
,,. NO. 1
NO. 2
PRESS
" ff' • •
PACKA
TNn TNFn n FMrn i... r ,;fc«~*r ,,,
1ACHINE •* T
MACHINE »-
" - 1 '-
JBUTOR SEPARATOR JT, "*
. » r*- " tl __
AND — . 1
1 TNT f.l EANFR ^
f ^
T *
GING SYSTEM
•; i f
1
1 *
v "V |
t
1 t
^ 1
-J4
i- , ••-
*-**• i
u •
I BUR BOX | '
rr — H •-
— v-v
•_I-^_I
i t
i 1
1 t
.-il '
EXHAUST
EXHAUST
EXHAUST
EXHAUST
EXHAUST
I
EXHAUST
t
1
EXHAUST
I
EXHAUST
V CYCWNE
D INLINE AI-R FILTER
O COVERED CONDENSER
X SACKS
Figure A-l. Cotton ginning system showing the 4 subsystems
and 10 exhausts that were sampled (11) .
GIN B
The particulate emission factors for gins processing picker-
harvested cotton were obtained by averaging the appropriate emis-
sion factors for Gins B through F. These emission factors are
given in Table A-l. Standard deviations or accuracy values were
not reported for these emission factors.
Gin B is the USDA Cotton Ginning Research Laboratory, Stoneville,
Mississippi (9). Source tests were conducted during the 1969
crop year. Isokinetic sampling was conducted in the same manner
as that used at Gin A. A process flow diagram and the eight
source sampling locations for this gin are shown in Figure A-2.
Fifty samples were collected from each exhaust between October 3
and November 17, 1969, while 100 bales of machine-picked cotton
59
-------
TABLE A-l. SUMMARY OF SOURCE TEST DATA FROM GINS
PROCESSING PICKER-HARVESTED COTTON
Emission source
unloading fan
No. 1
Ho. 2
Trash
dryer and cleaner
dryer and cleaner
fan
Gin B (9)
b0.228
Cyclone (2)
0.012
Cyclone (2)
O.OOS
Cyclone (2)
0.013
Cyclone (2)
Average
Gin C
0.359 t
Skimmer
0.234 i
Cyclone
0.086 ±
Cyclone
0.048 ±
Cyclone
emission factor, g/kg, and controls
(6)
0.199
0.190
(4)
0.020
(4)
0.037
(2)
Gin D (5)
0.248 ± 0.057
Cyclone (4)
0.204 ± 0.073
Cyclone (4)
Gin E
0.203 ±
Cyclone
0.181 ±
Cyclone
0.095 ±
Cyclone
(22) .
0.069
(4)
0.025
(2)
0.043
(2)
sampled
Gin F (23)
Wet scrubber
0.462 ± 0.270
Skimmer and spray column
Overflow fan
No. 1
No. 2
Mote
lint cleaner condenser
lint cleaner condenser
fan
Battery condenser
0.531
Standard drum covering
0.158
Standard drum covering
0.271
100 X 100 Mesh filter on drum
0.222
Standard drum covering
Master trash fan
0.768 ±
Skimmer
0.475 ±
Cyclone
0.314 ±
Skimmer
0.218 ±
Cyclone
0.104
0.197
(2)
0.289
0.250
(4)
0.667 i 0.243
Inline filter
0.532 ± 0.182
Inline filter
0.63 ± 0.075
Inline filter
0.87 ±
0.17
Inline filter
0.282 ±
Cyclone
0.016
(1)
0.0191 ± 0.0078
Wet scrubber
0.0127 ± 0.0037d
Wet scrubber
0.282 ± 0.05
Cyclone (2)
d
0.392
Wet scrubber
Average
0.259
0.158
0-185
0.052
0.19
0.655
0.388
0.277
0.519
0.250
± 0.
± 0.
± 0.
079
068
135
± 0.028
± 0.
± 0.
± 0.
± 0.
± 0.
019°
132
134
05
114
± 0.12
"Blanks indicate data not available. "Number in parentheses indicates the number of cyclones. Estimated from stripper-harvested cotton emissions.
Not used to calculate the average.
UNLOADING FAN
-TO TWIN CYCLONES
6 CYLINDER CLEANER
AND
STICK MACHINE
6
CYLINDER CLEANER
-TO TWIN CYCLONES
-TO TWIN CYCLONES
TRASH FAN
GIN STAND
AND FEEDER
TO TWIN CYCLONES
LINT CLEANER
WASTE CONDENSER
NO.
1 LINT CLEANER
TO ATMOSPHERE
NO.
2 LINT CLEANER
BATTERY CONDENSER
-TO ATMOSPHERE
-TO ATMOSPHERE
-TO ATMOSPHERE
Figure A-2. Flow diagram of Gin B (9).
60
-------
were being processed. The average trash content of the seed cot-
ton was 7.6% (personal communications, R. A. Wesley and
0. L. McCaskill. USDA Cotton Ginning Research Laboratory, Stone-
ville, Mississippi, June 4, 1975).
GIN C
This gin was sampled by a private consulting firm for the Texas
Air Control Board for the purpose of obtaining source test data
and establishing test methods applicable to agricultural process-
ing industries (6). The gin is located in South Texas and proc-
esses picker-harvested cotton at an average rate of 10.8 bales/hr.
During the 10-day sampling period, 56 samples were taken from
eight source locations (Table A-l). Candy-cane-shaped ducting
was installed on the exhausts of all cyclones that were sampled
in order to insure isokinetic sampling procedures.
GIN D
Gins D, E, and F were sampled by MRC under EPA Contract No.
68-02-0226 for the purpose of obtaining source test data from
gins equipped with the best types of pollution control equipment
currently available (5, 20, 21).
Emission points on all three gins were equipped with candy-cane-
shaped duct extensions to permit isokinetic sampling. Care was
taken in the design of the ducting so as not to change the back
pressure (and collection efficiency) of each control device.
Gin D is located in Mississippi and processed machine-picked cot-
ton at a rate of about 20 bales/hr. The source test data are
summarized in Table A-l. A process flow diagram and the sampling
locations are shown in Figure A-3. All emission points at Gin D
were equipped with either small-diameter, high-efficiency
cyclones or inline filters.
GIN E
This gin is located in Georgia and processed picker-harvested
cotton at approximately 9 bales/hr. A process flow diagram for
this gin is shown in Figure A-4 (20). All exhaust points were
controlled with either small-diameter, high-efficiency cyclones
or inline filters.
The source test data are summarized in Table A-l.
GIN F
This gin is located in California and processed picker-harvested
cotton at about 10 bales/hr. Figure A-5 shows the process flow dia-
gram (21). Wet scrubbers were used on the outlets of the battery
condenser and all six lint cleaners. Two skimmer-spray column
61
-------
combinations were used to control the emissions from the inclined
cleaners, overflow separators, moisture conditioning hoppers, and
the extractor feeders.
The emissions from this gin were sampled in early December 1972
and the results are summarized in Table A-l.
62
-------
CYCLOKE
(V>-SCREW CONVEYOR
UNLOADING AT TRAILERS
(TELESCOPE SUCTION TUBE)
LINT CLEVER UNT CLEANERS (2)
FAN
ABBREVIATIONS:
A - AIR
SC - SEED COTTON
LC - LINT COTTON
S - SEED
T - TRASH
NG - NATURAL GAS
db
CYCLONE
do CD
CYCLONE CYCLONE
LC BALES
" (500 Ib)
Figure A-3. Flow diagram of Gin D (5).
-------
I CYCLONE
CTi
STONE T'RAP
UNLOADING AT TRAILERS
(TELESCOPE SUCTION TUBE)^
STONES,
GREEN
BOLLS
CYCLONE
TELESCOPE
SUCTION TUBE
UNLOADING SEPARATOR
A.SC
QD CYCLONE
)CYCLONE
'FAN A.SC INCLINED CLEANER O FAN
v^*\ >-
\V^v "*
A.SC
r *
TQWER
DRYER
#2
C
c
AjSC DRYER #2 SEPARATOR (JFAN
A.T
$
VACUUM DROPPER
(NOT IN OPERATION)
SC OVERFLOW
SEPARATOR
(BYPASSED]
INLINE FILTERS
SCREW CONVEYOR
WITH DROPPER
AND GLOWER
LC BALES
(500 Ib)
ABBREVIATIONS:
A - AIR
SC - SEED COTTON
LC - LINT COTTON
S - SEED
T - TRASH
NG - NATURAL GAS
Figure A-4. Flow diagram of Gin E (20).
-------
VED
en
FIRST CLEANING STAGE
GRID CLEANERS
SECOND CLEANING STAGE
CLEANER
DAMPER
TELESCOPE
SUCTION TUBES
AT TRAILERS
GREEN LEAF AND
STICK REMOVER
I TRAILER DUMP
] I ! WITH
L J FEED CONTROL
THIRD CLEANING STAGE
IMPACT CLEANERS (2)
SC - SEED COTTON
LC - LINT COTTON
M - MOTES
T - TRASH
S - SEED
NG - NATURAL GAS
VED - VERTICAL EXHAUST DUCT
HED - HORIZONTAL EXHAUST DUCT
TRASH FAN
Figure A-5. Flow diagram of Gin F (21).
-------
GLOSSARY
batt: Matting of lint cotton in the condenser drum as the lint
is separated from the conveying air.
battery condenser: Final condenser at the gin press that col-
lects lint cotton from air-conveying systems.
bur: Rough casing surrounding the seed cotton before the boll is
opened.
candy cane: Ducting attached to the top of an elevated cyclone,
then connected to an inverted U-shaped section of duct and
finally extended down to the ground—the shape resembling a
candy cane.
condenser drum: Device located over a lint cleaner or lint slide
that separates the lint cotton from the conveying air stream;
device normally consists of a cylinder covered by perforated
metal that contains holes about 2.5 mm in diameter.
cotton dust: Dust generated as a result of the processing of cot-
ton fibers combined with naturally occurring materials such
as soil, stems, leaves, sticks, bracts, and inorganic matter
that may have accumulated on the cotton fibers during the
growing or harvesting period.
cylinder cleaner: Machine with rotating cylinders that remove
dirt and small trash from the seed cotton but do not remove
large trash.
defoliation: Naturally or artificially induced shedding of leaves
from the cotton plant; chemicals are normally used to defoli-
ate cotton to aid mechanical harvesting.
desiccation: Killing leaves and reducing the leaf moisture con-
tent on the cotton plant with a chemical; leaves do not wilt
and fall off plant as in defoliation.
distributor: Device to apportion seed cotton to various machines
or gin stands; excess cotton from this device is discharged
to the overflow system; a distributor may be of the belt or
pneumatic type or equipped with an auger or helical screw.
66
-------
doffing: Act or process of removing lint cotton from any part of
a machine; function can be accomplished with rollers,
brushes, or a blast of air.
extractor: Device for removing large trash such as burs, sticks,
stems, and leaves from seed cotton; device may accomplish
cleaning but should not be confused with a cleaner.
gin stand: Machine that separates the cotton lint from the seed.
inline filter: Device that cleans lint fly and cotton dust from
the conveying air before discharging the air to the
atmosphere.
lint cleaner: Machine for removing foreign matter from lint
cotton.
lint fly: Short (less than 50 vim) cotton fibers emitted from the
condensers and mote fan.
mote: Immature cotton seed with short, immature fibers attached.
picker-type harvester: Harvesting machine that removes cotton
from the bur with rotating spindles, leaving unopened bolls
on the plant.
separator: Inline machine that separates seed cotton from the
conveying air.
stick machine: Machine that efficiently removes sticks and green
leaves from the seed cotton.
stripper-type harvester: Harvesting machine that pulls or strips
all cotton bolls, open and unopen, from the plant; machine
also collects relatively large amounts of leaves, sticks,
and stems.
67
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
\. REPORT NO.
EPA-600/2-78-004a
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
SOURCE ASSESSMENT: COTTON GINS
6. REPORT DATE
January 1978(issuing date)
0. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
G. D. Rawlings and R. B. Reznik
8. PERFORMING ORGANIZATION REPORT NO.
MRC-DA-726
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Monsanto Research Corporation
1515 Nicholas Road
Dayton, OH 45407
1O. PROGRAM ELEMENT NO.
1AB604
11. CONTRACT/GRANT NO.
68-02-1874
12. SPONSORING AGENCY NAME AND ADDRESS
Industrial Environmental Research Laboratory—Cin,, OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Task Final, 4/75-11/77
14. SPONSORING AGENCY CODE
EPA/600/12
15. SUPPLEMENTARY NOTES
IERL-Ci project leader for the report is H. Kirk Willard
16. ABSTRACT
This report describes a study of air pollutants from cotton gins. Cotton gins
separate cotton fibers from cottonseed and trash. During the 1976 crop year,
2.6 x 106 metric tons of lint cotton were ginned. Particulates composed of cotton
dust, cotton lint, fine-leaf trash, and other trash are released to the atmosphere
during each step of the ginning process. The average particulate emissions for the
entire process is 3.14 g/kg of cotton ginned. Potential environmental effects from
ginning were assessed by determining the source severity at a typical plant boundary.
Severity is defined as the ratio of the ground level particulate concentration to a
reduced TLV. Source severities for nine individual emission points at a typical gin
ranged from 1 to 40> while the severity for one other point was less than 0.01. Cotton
gins in the United States use a combination of cyclones, separators, condensers, and
inline filters to separate cotton and trash from the conveying air stream and to
reduce air emissions.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Air Pollution
Assessments
Cotton Plants
Agricultural Machinery
b.lDENTIFIERS/OPEN ENDED TERMS
Air Pollution Control
Source Assessment
Source Severity
Cotton Gins
COSATI Field/Group
13B
8. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (This Report)
Unlimited
21. NO. OF PAGES
80
20. SECURITY CLASS (This page I
Unlimited
22. PRICE
EPA Form 2220-1 (9-73)
68
ft U.S. GOVERNMENT PRINTING OFFICE: 1978— 757-140/6673
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