United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S7-86/039 Mar. 1987
Project Summary
Ferroalloy Industry Particulate
Emissions: Source Category
Report
Evelyn J. Limberakis, Joseph Vay, and Stephen Gronberg
A review was made of all available
data characterizing paniculate emis-
sions from ferroalloy producing electric
arc furnaces. The data were summa-
rized and rated in terms of reliability.
Total and size specific emission factors
were developed for the ferroalloy in-
dustry. The ferroalloy industry and fur-
nace operation were described in detail
with emphasis on factors affecting
emissions. A replacement for Section
7.4 (Ferroalloy Production) of EPA re-
port AP-42, A Compilation of Air Pollu-
tant Emission Factors, was prepared,
containing the size specific emission
factors developed during this program.
This Project Summary was devel-
oped by EPA's Air and Energy Engineer-
ing Research Laboratory, Research Tri-
angle Park, NC, to announce key
findings of the research project that is
fully documented in a separate report
of the same title (see Project Report
ordering information on back).
Introduction
The purpose of this program was to
summarize the best available informa-
tion on inhalable particulate matter
emissions in the ferroalloy industry.
The main objective of the program was
to develop reliable total and size-
specific emission factors for each fer-
roalloy product group. Both uncon-
trolled and controlled emission factors
are presented in this report. The uncon-
trolled emission factors represent emis-
sions that would result from a particu-
late control system if the control device
(baghouse, scrubber, etc.) were by-
passed. The controlled emission factors
represent emissions emanating from a
particulate control system. Size specific
emission factors are generally based on
the results of cascade impactor sam-
pling conducted simultaneously with
total particulate sampling at the inlet or
outlet to a control device.
A second objective of this program
was to present current information on
the ferroalloy industry. A third objective
was to prepare a replacement for Sec-
tion 7.4, Ferroalloy Production, in AP-
42, "A Compilation of Air Pollutant
Emission Factors."
The above objectives were met by an
intensive 10 week search for data. Data
were collected from the following
sources:
• New England Research Application
Center (NERAC) computerized liter-
ature searches
• Telephone conversations with state
and federal EPA personnel
• Industry personnel
• Environmental consultants
• GCA/Technology Division files
• AP-42 ferroalloy background file at
EPA's Office of Air Quality Planning
and Standards
• Fine Particle Emission Information
System (FPEIS)
The particulate emissions data con-
tained in the referenced documents
were reviewed, analyzed, summarized,
and ranked according to the criteria pro-
vided in the report, "Technical Proce-
dures for Developing AP-42 Emission
Factors and Preparing AP-42 Sections,"
April 1980. After ranking the data, emis-
sion factors were calculated using the
highest quality data available. The qual-
ity of the data used to develop each
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emission factor is indicated by the emis-
sion factor rating.
Process control system operating
data as well as general industry infor-
mation were also obtained and summa-
rized as general background informa-
tion. It was not the objective of this
program to provide detailed engineer-
ing analyses, product specifications, or
detailed evaluations of trends in the in-
dustry.
Summary of Project Results
Emissions are generated from several
activities at a ferroalloy facility includ-
ing raw material handling, smelting,
and product handling. The emission
factors presented in Tables 1 and 2 rep-
resent controlled and uncontrolled
emissions from a ferroalloy smelting
furnace. Emissions from raw material
handling, pretreatment operations, and
product handling are not included due
to insufficient data. The smelting fur-
naces are by far the largest paniculate
emission source in a ferroalloy plant.
Fugitive emissions from open sources
are treated in a different report.
Furnace emissions are captured by
hoods (for open furnaces) or aspirated
directly from the furnace (for closed fur-
naces). Baghouses are used to control
emissions generated from 85 percent of
open furnaces in the U.S., while scrub-
bers are used on 13 percent of furnaces
and electrostatic precipitators on 2 per-
cent. Scrubbers are used almost exclu-
sively to control high temperature ex-
haust gases from closed (sealed)
furnaces. Scrubbers do not remove
much CO and H2.
Control efficiencies for well designed
and operated control systems (i.e., bag-
houses with air-to-cloth ratios of 1 - 2
ftVft2 (18-38 m3/m2), and srubbers with
pressure drops of 55 - 96 in. H20 (19-24
kPa) have been reported to be in excess
of 99 percent. It must be stressed that
conscientious maintenance of the con-
trol system is necessary if such high
efficiencies are to be consistently
achieved.
Emissions from tapping can often be
significant. Some plants capture these
Table 1. Emission Factors for Paniculate from Submerged Arc Ferroalloy Furnaces'
Paniculate emission factors
(uncontrolled)11
Furnace kg/Mg lib/ton) Size factor
Product* type alloy kg (lb)/MW-hr data Notes rating Control device11
FeSi(50%) Open 35 (70) 7.4 (16.3) Yes e,f B Baghouse
Covered 46 (92) 9.3 (20.5) £ Scrubber
High energy
Low energy
Particulate emission factors
(controlled^
kg/Mg (Ib/ton)
alloy
0.9
0.24
4.S
(1.8)
(0.481
(9.0)
kg (IbVMW-hr
0.2
0.05
0.77
(0.4)
(0.11
(1.7)
Size
data Notes
Yes e
g
0
Emission
factor
rating
B
E
E
FeSi (75%)
Open 158
Covered 103
FeSi (90%) Open 282
Si metal (98%) Open 436
FeMn (80%) Open 14
(316)
(206)
(564)
(872)
(28)
16
13
24
33
4.8
(35)
(29)
(53)
(73)
(11)
Yes
Yes
Yes
g
h
i
E
E
E
B
B
Scrubber
Low energy 4.0
(8.0) 0.5
(1.1)
Baghouse
16
0.24
Baghouse
Scrubber
High energy 0.8
(32) 1.2 (2.6)
(0.48) 0.078 (0.2)
(1.6) 0.34 (0.7)
Yes h
Yes i
1
B
B
E
FeMn (1% Si) Covered
Sealed
FeCr (high
carbon)
SiMn
Open
Open
Sealed
6
37
78
96
-
(12) 2.4
(74) 17
(157) 15
(192) 20
(-) -
(5.3)
(37)
(33)
(44)
(-)
Yes
Yes
k
1
n
o
4
E
E
C
C
High energy
ESP
Scrubber
Scrubber
High energy
0.25
1.2
2.1
0.15
(0.5) 0.10
(2.3) 0.23
(4.2) 0.44
(0.30) 0.016
(0.2)
(0.5) Yes
(1.0) Yes
(0.04)
i,m
n
P
m
C
C
C
E
'Factors are for main furnace dust collection system before and after control device. Where other emissions, such as leaks or tapping, are included or quantified
separately, such is noted. Particulate sources not included: raw material handling, storage, preparation; and product crushing, screening, handling, packaging.
^Percentages are of the main alloying element in product.
'In most source testing, fugitive emissions not measured or collected. Where tapping emissions are controlled by primary system, their contribution to totai
emissions could not be determined. Fugitive emissions may vary greatly among sources, with furnace and collection system design and operating practices.
''Low energy scrubbers are those with AP <20 in. HjO; high energy, with AP >20 in. Hfl.
'Includes fumes captured by tapping hood (efficiency estimated near 100%).
fFactor is average of three sources, fugitive emissions not included. Fugitive emissions at one source measured an additional 10.5 kg/Mg alloy, or 2.7 kg/MW-hr
eDoes not include emissions from tapping or mix seal leaks.
^Estimated 60% of tapping emissions captured by control system (escaped fugitive emissions not included in factor).
'Estimated 50% of tapping emissions captured by control system (escaped fugitive emissions not included in factor).
ilncludes fume only from primary control system.
^Includes tapping fumes and mix seal leak fugitive emissions. Fugitive emissions measured at 33% of total uncontrolled emissions.
>Assumes tapping fumes not included in emission factor.
mDoes not include tapping or fugitive emissions.
"Tapping emissions included. Factor developed from two test series performed on the same furnace 7 years apart. Measured emissions in latter test were 36% les
than in former.
"Factor is average of two test series. Tests at one source included fugitive emissions (3.4% of total uncontrolled emissions). Second test insufficient to determin
if fugitive emissions were included in total.
PFactors developed from two scrubber controlled sources: one operated at AP = 47-57 in. HjO; the other at unspecified AP. Uncontrolled tapping operation
emissions are 2.1 kg/Mg alloy.
iDash = No data.
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Table 2. Size Specific Emission Factors
Control
Product device
50% FeSi
Open furnace Noneb
Baghouse
80% FeMn
Open furnace Noned
80% FeMn
Open furnace Baghoused
Si Metal
Open furnace None"
Baghouse
for Submerged Arc
Panicle size"
(\i.m)
0.63
1.00
1.25
2.50
6.00
10.00
15.00
20.00
c
0.63
1.00
1.25
2.50
6.00
10.00
15.00
20.00
0.63
1.00
1.25
2.50
6.00
10.00
15.00
20.00
c
0.63
1.00
T.25
2.50
6.00
10.00
15.00
20.00
C
0.63
1.00
1.25
2.50
6.00
10.00
15.00
20.00
C
1.00
1.25
2.50
6.00
10.00
15.00
20.00
Ferroalloy Furnaces
Cumulative mass %
s stated size
45
50
53
57
61
63
66
69
100
31
39
44
54
63
72
80
85
100
30
46
52
62
72
86
96
97
100
20
30
35
49
67
83
92
97
100
57
67
70
75
80
86
91
95
100
49
53
64
76
87
96
99
100
Cumulative mass
emission factor
kg/Mg (Ib/ton) Emission factor
alloy rating
16
18
19
20
21
22
23
24
35
0.28
0.35
0.40
0.49
0.57
0.65
0.72
0.77
0.90
4
7
8
a
10
12
13
14
14
0.048
0.070
0.085
0.120
0.160
0.200
0.220
0.235
0.240
249
292
305
327
349
375
397
414
436
7.8
8.5
10.2
12.2
13.9
15.4
75.8
76.0
(32) B
(35)
(37)
(40)
(43)
(44)
(46)
(48)
(70)
(0.56) B
(0.70)
(0.80)
(1.0)
(1.1)
(1.3)
(1.4)
(1.5)
(1.8)
(8) B
(13)
(15)
(17)
(20)
(24)
(26)
(27)
(28)
(0.10) B
(0.14)
(0.17)
(0.24)
(0.32)
(0.40)
(0.44)
(0.47)
(0.48)
(497) B
(584)
(610)
(654)
(698)
(750)
(794)
(828)
(872)
(15.7) B
(17.0)
(20.5)
(24.3)
(28.0)
(31.0)
(31.7)
(32.0)
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Table 2. Size Specific Emission Factors for Submerged Arc Ferroalloy Furnaces—Continued
Cumulative mass
emission factor
Control Particle size*
Product device (v-m)
FeCr (HC>
Open furnace Noneb 0.5
1.0
2.0
2.5
4.0
6.0
10.0
c
ESP 0.5
1.0
2.5
5.0
6.0
10.0
c
Cumulative mass %
£ stated size
19
36
60
63'
76
88'
91
100
33
47
67
80
86
90
100
kg/Mg (Ib/ton)
alloy
15
28
47
49
59
67
71
78
0.40
0.56
0.80
0.96
1.03
1.08
1.2
(30)
(57)
(94)
(99)
(119)
(138)
(143)
(157)
(0.76)
(1.08)
(1.54)
(1.84)
(1.98)
(2.07)
(2.3)
Emission factor
rating
C
C
SiMn
Open furnace A/one* 0.5
1.0
2.0
2.5
4.0
6.0
10.0
c
Scrubbers 0.5
1.0
2.5
5.0
6.0
10.0
28
44
60
65
76
85
96'
100
56
80
96
99
99.5
99.9'
100
27
42
58
62
73
82
92'
96
1.18
1.68
2.02
2.08
2.09
2.70'
2.1
(54)
(84)
(115)
(125)
(146)
(163)
(177)'
(192)
(2.36)
(3.44)
(4.13)
(4.26)
(4.28)
(4.30)'
(4.3)
C
C
3Aerodynamic diameter, based on Task Group on Lung Dynamics definition.
Particle density = 1 g/cm3.
b Includes tapping emissions.
cTotal paniculate, based on Method 5 total catch (see Table 1).
^Includes tapping fume (capture efficiency 50%).
"Includes tapping fume (estimated capture efficiency 60%).
'Interpolated data.
^Primary emission control system only, without tapping emissions.
emissions in varying degrees using the
main canopy hood, and others employ
separate tapping hoods ducted to either
the furnace control device or a separate
control device. Emission factors for tap-
ping operations are unavailable due to
the lack of data.
E. J. Limberakis, J. Vay, and S. Gronberg are with GCA/Technology Division,
Bedford, MA 01730.
Dale L. Harmon is the EPA Project Officer (see below).
The complete report, entitled "Ferroalloy Industry Paniculate Emissions: Source
Category Report," (Order No. PB 87-129 268/AS; Cost: $18.95, subject to
change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Air and Energy Engineering Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park. NC 27711
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Information
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EPA/600/S7-86/039
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