MIDWEST RESEARCH INSTITUTE
REPORT
OPEN DUST SOURCES AROUND
IRON AND STEEL PLANTS
SPECIAL REPORT
ADDENDUM
Prepared for:
Industrial Environmental Research Laboratory
Environmental Protection Agency
Research Triangle Park
North Carolina 27711
Under Contract No. 68-02-2120
MRI Project No. 4123-L
Special Report
Date Prepared: February 4, 1977
by
Midwest Research Institute
425 Volker Boulevard
Kansas City, Missouri 64110
MIDWEST RESEARCH INSTITUTE 425 VOLKER BOULEVARD, KANSAS CITY, MISSOURI 64110 • 816753-7600
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MRI-NORTH STAR DIVISION 3100 38th Avenue South, Minneapolis, Minnesota 55406 • 612 721-6373
MRI WASHINGTON, D.C. 20005- 1522 K STREET, N.W. • 202 293-3800
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600R77009
OPEN DUST SOURCES AROUND
IRON AND STEEL PLANTS
SPECIAL REPORT
ADDENDUM
Prepared for:
Industrial Environmental Research Laboratory
Environmental Protection Agency
Research Triangle Park
North Carolina 27711
Under Contract No. 68-02-2120
MRI Project No. 4123-L
Special Report
Date Prepared: February 4, 1977
by
Midwest Research Institute
425 Volker Boulevard
Kansas City, Missouri 64110
MIDWEST RESEARCH INSTITUTE 425 VOLKER BOULEVARD, KANSAS CITY, MISSOURI 64110 • 816753-7600
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PREFACE
This report addendum was prepared for the Environmental Protection Agency
(Mr. Robert V. Hendriks, Project Officer) to present the results of a sur-
vey of open dust sources around an iron and steel plant. The work was per-
formed in the Environmental and Materials Sciences Division of Midwest
Research Institute under EPA Contract No. 68-02-2120. This report was
written by Dr. Chatten Cowherd and Mr. Russell Bohn.
Approved:
MIDWEST RESEARCH INSTITUTE'
L. J. Shannon, Director
Environmental and Materials
Sciences Division
February 4, 1977
11
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TABLE OF CONTENTS
1.0 Introduction 1
2.0 Unpaved Roads 1
2.1 Source Extent 1
2.2 Correction Parameters 4
3.0 Aggregate Storage Piles 5
3.1 Loading Onto Piles 7
3.2 Vehicular Traffic 7
3.3 Wind Erosion 8
3.4 Load-out 9
4.0 Wind Erosion of Exposed Areas 9
5.0 Summary of Dust Emissions 10
References '14
List of Tables
No. Title Page
1 Experimentally Determined Fugitive Dust Emission Factors . . 2
2 Plant D - Road Emissions 3
3 Plant D - Storage Pile Emissions 6
4 Plant D - Open Area Emissions 11
5 Plant D - Summary of Open Dust Source Emissions 12
6 Plant D - Unit Emissions 13
iii
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1.0 Introduction
Significant quantities of fugitive dust may be emitted from storage
piles, vehicular traffic, and wind erosion of exposed areas around
iron and steel plants. Reliable estimates of these emissions require
the use of (a) data on source extent and/or activity levels and
(b) emission factors which have been appropriately corrected for local
climatic conditions and silt (fines) content of the emitting surface.
Table 1 lists the measures of source extent, the basic emission fac-
tor formulae, and the correction parameters associated with each per-
tinent source category. The mathematical expressions for each emis-
sion factor were derived from field measurements described in reports
1-3 /
prepared by Midwest Research Institute (MRI). Supporting informa-
tion for several of these factors is presented in EPA's Emission Fac-
tor Handbook.— The factors presented in Table 1 describe emissions
of particles smaller than 30 u in diameter, the approximate effective
cutoff diameter of a standard high volume particulate sampler (based
on particle density of 2 to 2.5 g/cnr).—'
This report presents the results of a survey of open dust sources at
a representative iron and steel plant, designated as Plant D. Sur-
vey results and procedures are given below for each source category,
following the format used in the report for Plants A and B, dated
November 2, 1976, and in the report for Plant C, dated January 11,
1977.
2.0 Unpaved Roads
Table 2 lists source extent and activity factors, emission factor cor-
rection parameters, and calculated emission rates for specific unpaved
roads lying within the property boundaries of Plant D. The plant had
no paved roads within its boundaries.
The experimentally determined emission factors for unpaved roads given
in Table 1, with an additional correction for vehicle weight, were
used to calculate fugitive dust emissions. The appropriate measure
of source extent is vehicle-miles traveled.
2.1 Source Extent
The following steps were used to develop the inventory of roads, ve-
hicle types, and mileage traveled:
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Table 1. EXPERIMENTALLY DETERMINED FUGITIVE DUST EMISSION FACTORS
a/
Source category
Aggregate storage
(sand and gravel;
crushed stone)
Unpaved roads
Paved roads
Wind erosion
Measure of extent
Tons of aggregate put
through storage cycle
Vehicle-miles traveled
(light duty)
Vehicle-miles traveled
(light duty)
Acre-years of exposed
land
Emission factor—
(Ib/unit of
source extent)
0.33
(PE/100)2
0-49
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Table 2. PLANT D - ROAD EMISSIONS
Roads
Unpaved
Road length-'
(miles)
10.6
Source extent
Vehicle class:
Light Duty A
Medium Duty B
Heavy Duty C
A
B
C
Vehicle-miles
traveled'1
(miles/day)
720
WO
120
Vehicle weight
correction
(based on
observation)
1.0
3.5
8.0
Correction factors
Vehicle speed-'
(mph)
20
20
15
Road surface
silt content—'
(%>
10
10
10
Emission
factor
(Ib/VMT)
2.3
8.1
13.7
Emissions-
Dally
emissions
(tons /day)
0.8
1.8
0.8
Yearly
emissions
(tons/year)
292
657
292
Total
10.6
1,280
3.4
1,241
a_/ Determined from plant map.
b/ Data obtained from plant personnel.
c_/ Assumed value.
d/ All emissions are based on partlculates less than 30 n In diameter.
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1. Unpaved road segments with specific surface and traffic charac-
teristics were identified by plant personnel, and the length of
each segment was determined from a map of the plant.
2. • The types and sizes of the vehicles traveling on unpaved roads
were specified by plant personnel.
3. Figures on the daily mileages traveled by each vehicle type were
furnished by plant personnel.
All of the roads at Plant D boundary are slag surfaced. As indicated
in Table 2, total unpaved road mileage within the plant is 10.6 miles.
These roads were indicated to be in good condition throughout the
plant and to be regularly maintained.
Vehicular traffic at Plant D was comprised of three basic vehicle
types:
* Type A - light duty, 36 vehicles (automobiles and pickup trucks).
* Type B - medium duty, 22 vehicles (flatbeds and other medium
sized trucks).
* Type C - heavy duty, 6 vehicles (larger trucks with load capacity
greater than 25 tons).
As indicated by plant personnel, these vehicles travel over all the
unpaved roads in the plant. Thus, no specific plant road segments
were identified as having higher than average traffic volumes.
2.2 Correction Parameters
Because of adverse weather conditions during the time of the survey,
it was not possible to obtain representative samples of road surface
dust from which to determine silt content. Therefore, a silt content
of 10% for the road surface material was assumed. Average vehicle
speed was estimated by plant personnel and the number of dry days per
year for the plant locale was determined from the Climatic Atlas.—'
Because the experimentally determined emission factors for unpaved
roads were developed for light duty vehicles, it was necessary to
apply vehicle weight correction multipliers to account for increased
emissions from medium duty and heavy duty vehicles. It was assumed
that emissions increase in proportion to vehicle weight. Ratio of
average empty truck weights to average light duty vehicle weight
(4 tons) were used as correction multipliers, because trucks travel
at higher speeds during the unloaded portions of travel cycles.
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3.0 Aggregate Storage Piles
An inherent part of the operation of integrated iron and steel plants
is the maintenance of outdoor storage piles of mineral aggregates
used as raw materials, and of process wastes. Storage piles are usually
left uncovered, partially because of the necessity for frequent trans-
fer of material into or out of storage.
Dust emissions occur at several points in the storage cycle—during
loading of material onto the pile, whenever the pile is acted on by
strong wind currents, and during load-out of material from the pile.
Truck and loading equipment traffic in the storage pile areas are
also a substantial source of dust emissions.
Table 3 gives data on the extent of open storage operations involving
primary aggregated materials at Plant D. This information was devel-
oped from (a) discussions with plant personnel, (b) plant statistics
on quantities of materials consumed, and (c) field estimations during
, the plant survey.
The emission factor for aggregate storage piles given in Table 1 was
derived from field measurements of dust emissions from active and in-
active storage piles of sand, gravel, and crushed stone. The major
operational contributions to storage pile emissions were found to be:
1. Loading onto piles from dumptrucks,
2. Vehicular traffic around piles during 90-day storage,
3. Wind erosion during 90-day storage, and
4. Load-out from piles to dumptrucks utilizing high loaders.
As expected, the quantity of emissions is directly proportional to
the amount of material put through the storage cycle.
Because aggregate storage operations in the iron and steel industry are
similar to operations described above, the experimentally determined
emission factor and operational contributions were used as a basis for
the development of estimated emission factors for each material/operation
combination. In each case, the factor was adjusted to the content of
silt (fines) in the given aggregate and to the degree of material-
handling equipment activity in comparison with the operations used in
the sand and gravel and crushed stone industries.
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Table 3. P1ANT D - STORAGE PILE EMISSIONS
Material
in
storage
low vola-
tility
coal
High vola-
tility
coal
Iron ore
pellets
Screened
iron ore
Coke breeze
Screened
limestone/
dolomite
Dolomite
stone
Total
Source
Amoun t
In
storage
(tons)—
25,000
30,000
50,000
66,600
40,000
5,000
12,000
216,600
extent Correction factors
Annual Duration
thruput Silt of Load-in
(million content storage (Ib/ton
tons)^ (%)-' (days)^' stored)
0.05 5.5 180 0.2
0.06 2 360 0.1
1.8 13 10 0.3
.0.4 19 60 0.5
0.04 7 90 0.2
0.14 9^ 13 0.2
0.04 1.5-' 45 0.04
2.49
Emission factors-
Total
Vehicular Wind storage
traffic erosion Load-out cycle
(Ib/ton (Ib/ton (Ib/ton (Ib/ton
stored) stored) stored) stored)
0.3 ' 0.9 0.2 1.6
0.1 0.7 0.1 1.0
0.7 0.1 0.5 1.6
£' 1.1 0.7 2.3
0.7 0.6 0.3 1.8
0.9 0.1 0.3 1.5
0.1 O.I 0.1 0.4
Yearly
emissions
(tons/year)
40
30
1,440
460
36
105
a
2,119
a/ Data obtained from plant personnel.
b/ Assumed silt content based on sieving of similar materials.
£/ Calculated from data obtained from plant personnel.
d/ Assumed value.
e/ Determined negligible.
I/ All emissions are based on participates less than 30 u in diameter.
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During the survey, weather conditions prohibited the collection of
representative samples of the storage.materials to be analyzed for
silt content. Storage pile silt content values were assumed to be
the same as the values obtained for similar materials previously sized
at other steel plants.
Table 3 presents the emission factors for the storage of primary aggre-
gate materials used in integrated iron and steel plants. The rationale
for the derivation of the emission factor expression for each operation
is given below.
3.1 Loading Onto Piles
The method of loading onto storage piles at Plant D consisted of uti-
lizing front-end loaders for the coke breeze and screened stone piles;
a stacker for the iron pellet piles; and an overhead gantry/clamshell
drop for the screened iron ore, large stone, and for the coal piles.
The front-end loader and gantry drop method of loading onto the piles
is considered comparable to the operations for which field measure-
ments were performed. The stacker method of pile formation was judged
to emit less dust than the emission-tested load-in process, so an activ-
ity factor of 0.75 was incorporated into the load-in emission factor
equation. Based on these assumptions, the following equation was used
to derive emission factors for the procedure of pile load-in:
EFX = 0.04 (S/1.5) K
where EFi = emission factor (Ib/ton of material transferred)
0.04 = experimentally determined emission factor for loading
of sand and gravel
x
S = silt content of given aggregate material (percent)
1.5 = silt content of emission-tested material (percent)
K = activity factor (0.75 for iron pellets, 1.0 for all
other materials)
3.2 Vehicular Traffic
Vehicular traffic around emission-tested aggregated storage piles,
consisting of truck and high-loader movements associated with
load-in and load-out, was generally more intense than traffic
around storage piles at the iron and steel plant. The following
stored aggregate materials were assigned a reduced traffic-related
activity factor:
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Screened iron ore: K = 0 (no vehicular traffic)
Iron ore pellets: K = 0.5
Coal: K = 0.5
Large stone: K = 0.5
The coal, coke breeze, and screened stone storage piles at Plant D
were worked in a manner similar to the emission-tested aggregate,
and were thus assigned a K-factor of 1.
Based on these considerations, emission factors for traffic around
the storage piles were calculated using the following equation:
- 0.13 (S/1.5)
C,Cn ~ „— JS.
2 (PE/100)2
where EF9 = emission factor (Ib/ton of material stored)
PE = "Thornthwaites precipitation-evaporation index (93)
S = silt content of given aggregate material (percent)
K = activity factor
The value 0.13 Ib/ton was the factor experimentally determined for
vehicle-generated emissions around the emission-tested aggregate
piles. These test piles had an average silt content of 1.5% and the
area where the testing occurred had a PE index of 100.
3.3 Wind Erosion
The correction factors deemed to be appropriate for dust emissions
generated by wind erosion were silt content, PE index, and length of
time material is in storage. The silt content and PE index were ra-
tioed in the same manner as for the traffic-related factor. Because
the relationship of emissions to duration in storage was assumed to
be linear, the correction multiplier is simply a direct ratio between
the duration of given material in storage, and the 90-day estimate of
duration for emission-tested aggregate materials. These assumptions
are incorporated into the following equation:
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(PE/100)2
where S = silt content of given stored material (percent)
PE = Thornthwaites precipitation-evaporation index (93)
D = duration of material in storage (days)
The value 0.11 Ib/ton was the factor experimentally determined for wind
erosion from piles with a silt content of 1.5% stored for 90 days in
a locality having a PE index of 100.
3.4 Load-out
The method of loading out from the piles at Plant D consisted of uti-
lizing either a front-end loader pickup and dump into a conveyor bin
(coal, ore pellets, coke breeze, and stone piles) or a gantry/clamshell
removal and dump into a rail hopper car (iron ore) which released the
material onto an undergound conveyor. The activity level (K-factor)
for these two methods was judged to be similar in nature to the
emission-tested load-out process.
Based on these considerations, emission factors for aggregate load-out
were calculated by the following equation:
EF/ = O.Q5 v~, I..-, v
4. ' Js.
(PE/100)2
where EF4 = emission factor (Ib/ton of material stored)
S = silt content of stored material (percent)
PE = Thornthwaites precipitation-evaporation index (93)
K = activity factor = 1
The value 0.05 Ib/ton was the factor experimentally determined for
load-out of storage piles with a silt content of 1.5% in a locality
having a PE index of 100.
4.0 Wind Erosion of Exposed Areas
Unsheltered areas of bare ground around plant facilities are subject
to atmospheric dust generation by wind erosion, whenever the wind ex-
ceeds the threshold velocity of about 12 mph. The bare ground area
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within the boundaries of Plant D was estimated to be 10% of the plant
property, based on discussions with plant personnel during the plant
survey. To account for the sheltering effect of plant structures, the
effective exposed area was taken to be 7.5% of the plant property.
As indicated in Table 1, the parameters which influence the amount of
dust generation by wind erosion are soil erodibility, silt content of
the surface soil, precipitation-evaporation index, and fraction of
the time wind speed exceeds 12 mph. The soil erodibility factor (47)
and the surface silt content (15%) were derived from previous sieving
of similar surface soil materials at another steel plant. Thornthwaites
precipitation-evaporation index for Plant D was determined to be 93.—
Finally, the value for the fraction of time the wind speed was greater
than 12 mph (25%) was obtained from weather records.- The results
from wind erosion of Plant D's exposed areas are presented in Table 4.
5.0 Summary of Dust Emissions
A breakdown of calculated emissions from open dust sources at Plant D
is presented in Table 5. For Plant D, the largest contributing source
was the iron ore pellet piles. Unpaved roads were also a major contrib-
utor to Plant D's dust emissions inventory. The remaining sources have
relatively minor impact. Table 6 gives Plant D's emissions from open
dust sources, stated on a per ton of steel produced basis. Expressing
emissions in this manner is useful when comparing the emissions from
steel plants of various sizes.
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Table 4. PI ANT D - OPEN AREA EMISSIONS
Wind erosion
Plant D open areas
Total
plant
area
(acres)
1.1003-7
Source extent
Total
open
area
(acres)
Effective
open area
fraction
0.75*/
Soil
credibility
(tons/acre -year)
47k/
Correction
factors
Surface soil
silt content
(I)
IS*/
Mind
id/
speed—'
0.25
PE
Index^
93
Emission
f ac tor
(Ib/acre-year)
917
Emissions-'
Dally
emissions
(tons/day)
0.1
Yearly
emissions
(tons/year)S'
37
a/ Data obtained from plant personnel.
b/ Based on sieving of similar materials.
c/ Assumed value.
d_/ Fraction of the time the wind speed Is greater than 12 mph.
e_/ Thornthwaltes precipitation-evaporation Index
{_/ Based on participates less than 30 u In diameter.
g/ Yearly emissions = dally emissions multiplied by number of dry days per year.
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Table 5. PLANT D - SUMMARY OF OPEN DUST SOURCE EMISSIONS
Percentage
Source Tons of particulate per year— of total
1. Unpaved roads 1,241 37
2. Wind erosion - open areas 37 1
3. Storage piles
Low/high volatility coal 70 2
Iron ore pellets 1,440 42
Screened iron ore 460 14
Coke breeze 36 1
Stone piles 113 3
Total all open sources 3,397 100
a/ Based on particles less than 30 u in diameter.
12
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Table 6. PIANT D - UNIT EMISSIONS
Pounds of particulates— per
Source short ton of steel produced
Unpaved roads 1.7
Wind erosion - open areas 0.1
Storage piles 2.8
Total 4.6
a/ Based on particles less than 30 u in diameter.
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REFERENCES
1. Cowherd, C., Jr., K. Axetell, Jr., C. M. Guenther, and G. A. Jutze,
Development of Emission Factors for Fugitive Dust Sources, EPA
Publication No-. EPA-450/3-74-037, June 1974.
2. Cowherd, C., Jr., C. M. Guenther, D. Nelson, and N. Stich, Quantifica-
tion of Dust Entrainment From Paved Roadways, Final Report Draft,
EPA Contract No. 68-02-1403 (Task 7), March 31, 1976.
3. Cowherd, C., Jr., C. M. Guenther, D. Nelson, and K. Walker, Develop-
ment of a Methodology and Emission Inventory For Fugitive Dust For
the Regional Air Pollution Study, EPA Publication No. EPA-450/3-
76-003, January 1976.
4. Compilation of Air Pollution Emission Factors, U.S. Environmental
Protection Agency, Publication AP-42, October 1975.
5. Climatic Atlas of the United States, U.S. Department of Commerce,
Environmental Science Services Administration, Environmental Data
Service, U.S. Government Printing Office, Washington, D.C., June
1968.
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