-------
wastewater sources. Solid wastes, however, are generated by all plants in the
form of collected parti culates, slag, broken fabric filters, and sludge (when
scrubbers are used).
Table 5-8 summarizes data on the organic content of scrubber water outlet
streams obtained in the recent EPA Environmental Assessment Study.7 Individual
organic compounds were not quantified, but a number of high-molecular-weight
compounds were identified in the scrubber water of Furnace C-2. The more
predominant identified compounds were:
l *
Fluoranthene and/or pyrene
Benzo(a)pyrene and/or perylene and or 10, 11-benzofluoranthene
C15/16 benz°Pyrene> Possibly with a naphthalene group.
Analyses of grab samples of particulate collected in fabric filters
on
open furnaces showed concentrations of organics in the range of 65 to 384 ppm
by weight. In one case, POM compounds accounted for 1 to 3 percent of the
total organics in the particulate. Concentrations of 7031 ppm of organics were
detected in the particulate matter from a fabric filter controlling the emis-
sions leaking from the top of a mix-sealed furnace, and POM accounted for 15 to
20 percent of these organic compounds.
Other studies on organic concentrations in liquid streams include data on
the oil content of wastewater streams, which indicate a concentration of less
than 2 ppm by weight.
5.4 OTHER ATMOSPHERIC EMISSIONS
Limited data have been obtained on other atmospheric emissions from
ferroalloy furnaces. These include data on sulfur acids, gaseous hydrocarbons,
and metals.
5.4.1 Sulfur Oxides
A joint EPA-Ferroalloy Association report on ferroalloys stated that
sulfur oxide emissions were less than 20 parts per million (ppm) and never
exceeded 3.2 kg/h (7 Ib/h). For this reason, sulfur oxides are rarely
included in an emission test program. The results of one set of recent tests
showed concentrations of 69 to 74 ppm for a 20-MW silicon open furnace and 83
50
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TABLE 5-8, ORGANIC CONCENTRATIONS IN SCRUBBER WATER
DISCHARGE STREAMS
Furnace
A-l
A-2
B-2
C-T
C-2
mg/ liter
11. 2a
14.1b
551
134
71
kg/MW-h
0.11
0.12
1 .55
0.97
0.48
*8.2 percent adsorbed on solids.
344 percent adsorbed on solids.
51
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ppm from a 25-MW ferrosilicon open furnace. These concentrations amount to
approximately 45.5 kg/h (100 Ib/h) for each furnace, or 1.8 to 2.1 kg/MW-h (4
to 4.6 Ib/MW-h).
This value is considerably higher than the previously reported data,
possibly because of the higher sulfur content of the petroleum coke used in the
electrodes. Because the sulfur content of the feed materials was not measured
during the emission test, however, no direct correlation between feed compo-
sition and emissions can be made.
5.4.2 Nitrogen Oxides
No measurements have apparently been made for these compounds, but con-
centrations are expected to be very low because of the lack of oxygen in the
reaction zone.
5.4.3 Inorganic Constituents
Tests for the inorganic constituents of the furnace exhaust gases were
conducted on three furnaces as part of EPA's environmental assessment stud-
17 18
1es. * Table 5-9 summarizes the results of these tests. The tests on
Furnaces D-l and B-l (both open furnaces) were performed on the gas stream
preceding particulate control systems, and the test on Furnace D-2 (a closed
furnace) was performed on the gas stream after it had passed through a venturi
scrubber with a high pressure drop. Analyses of these samples were performed
largely by spark source mass spectrometry techniques on each fraction of the
sample collected with a source assessment sampling system. The fractions were
then added to obtain the values in Table 5-9. Arsenic, mercury, and antimony
were analyzed by atomic absorption.
Although data from the tests on Furnaces D-l and D-2 cannot be directly
compared (because they made different products), the much lower values for all
elements obtained in the test on Furnace D-2 after the scrubber still show that
the scrubber was very effective in reducing the emissions. The composition of
these components varies widely, depending on the material charged. Major com-
ponents were not quantified because they could not be analyzed by these tech-
niques.
52
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Of special concern are those metals the EPA has designated as priority
pollutants. These are summarized in Table 5-10 on a mg/MW-h (10~ Ib/MW-h)
basis.
No detailed data on particle size were obtained in these assessment
studies, but the cyclone catch in the particulate sampling trains confirms
previous data indicating that the particulates are largely less than 10 micro-
meters and frequently less than 1 micrometer in diameter.
54
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TABLE 5-10. FURNACE EMISSION RATES OF SELECTED METALS9
[mg/MW-h (10-6 lb/MW-h)]
Metal
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Copper
Lead
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
Furnace—product
D-2— SiMn
0.13 (0.29)
62.5 (138)
0.017 (0.037)
MC
MC
MC
2.75 (6.06)
4.25 (9.36)
MC .
0.21 (0.46)
0.14 (0.31)
0.30 (0.66)
MC
D-1-- FeMn
475 (1,046)
12,000 (26,432)
2.5 (5.5)
1,675 (3,689)
13,000 (28,630)
8,500 (18,720)
MC
127 (280)
1,000 (2,200)
375 (826)
250 (551)
750 (1,650)
MC
B-l--50% FeSi
2,584 (5,692)
866 (1,907)
1.3 (2.9)
1,811 (3,990)
5,751 (12,667)
MC
MC
3.8 (8.4)
3,990 (8,790)
342 (753)
6,901 (15,200)
54 (119)
MC
MC = M,ajor component.
aRates for D-l and B-l represent uncontrolled emissions; rates for D-2 represent
measured emissions after a venturi scrubber.
55
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REFERENCES FOR SECTION 5
Memo anc) attachments from C. Harvey, PEDCo Environmental, Inc., to R. W.
Gerstle, PEDCo Environmental, Inc., April 25, 1980, transmitting informa-
tion from EPA Region VI.
Letter from M. Hayward, State of Iowa Department of Environmental Quality,
to R. W. Gerstle, PEDCo Environmental, Inc., June 3, 1980.
Letter and attachments from M. Hayward, State of Iowa Department of
Environmental Quality, to R. W. Gerstle, PEDCo Environmental, Inc., June
3, 1980.
Letter and attachments from P. A. Nelson, State of Washington, Department
of Ecology, to J. Zieleniewski, PEDCo Environmental, Inc., April 18, 1980.
Copy of Emission Test Report from State of South Carolina. Sent to R. W.
Gerstle, PEDCo Environmental, Inc., May 15, 1980.
Copy of Emission Test Report from R. Gore, State of Alabama to R. W.
Gerstle, PEDCo Environmental, Inc., June 16, 1980.
Westbrook, C. W., and D. P. Daugherty. Draft Copy of Environmental
Assessment of Electric Submerged-Arc Furnaces for Production of Ferro-
alloys. Research Triangle Institute. EPA Contract 68-02-2630. March
1980. 206 pp.
Rudolph, J. L., et al. Ferroalloy Process Emissions Measurement. U.S.
Environmental Protection Agency, Research Triangle Park, North Carolina.
EPA-600/2-79-045, February 1979. 185 pp.
Yerino, L., and H. Belknap. Determination of Compliance Status and
Evaluation of Baghouse Rebuilding Efforts SKW (Airco) Alloys Plant. PEDCo
Environmental, Inc. EPA Contract No. 68-01-4147, Task 83. Auqust 1979
pp. 10 & 11.
10. Memos from L. Gibbs of PEDCo Environmental, Inc., to project file re-
garding contacts with regulatory personnel in Ohio, April 3 and 14, 1980.
11. Information from C. Mikoy, Ohio Environmental Protection Agency, North-
east Office, to R. W. Gerstle, PEDCo Environmental, Inc., April 17,
1980.
1.
2.
3.
4.
5.
6.
7.
8.
9.
56
-------
12. Telecori. P. McManus, U.S. Environmental Protection Agency, Region III, to
R. W. Gerstle, PEDCo Environmental, Inc., April 22, 1980, regarding
compliance status of ferroalloy plants.
13. Reference 7, p. 187.
14. Reference 7, p. 67*
15. Cywin, A., and P. W. Diercks. Development Document for Effluent Limita-
tions Guidelines and New Source Performance Standards for the Smelting and
Slag Processing Category. U.S. Environmental Protection Agency. Wash-
ington, D.C. Publication No. EPA-440/l-74-008a, February 1974. 169 p.
16. Dealy, J. 0., and A. M. Killin. Engineering and Cost Study of the Ferro-
alloy Industry. U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina. EPA-450/2-74-008, May 1974. p. VI-48.
17. Reference 7, pp. 119 and 120.
18. Reference 8, pp. 47 and 48. .
57
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SECTION 6
PRODUCTION PROCESSES AND BEST AVAILABLE CONTROL TECHNOLOGY
Because no ferroalloy facilities in the United States are subject to NSPS,
this section deals with process changes, the best control technology currently
available, and the operational problems of this technology. It also presents
cost data for fabric filter systems, by far the predominant method of emission
control.
The type of particulate emission control used varies with the type of
furnace. Scrubbers predominate on closed and semiclosed furnaces, and fabric
filters are by far the most widely used control devices on open furnaces.
Tapping fumes are generally vented to fabric filter systems (either separate
systems or the furnace's own control system).
6.1 FERROALLOY PRODUCTION PROCESSES
As described in Section 4, ferroalloys are produced by the following
processes: electric submerged-a"c furnace at 31 locations, metalothermic at
8 locations, and electrolytic at 4 locations. The single blast furnace, in
operation until a few years ago, is no longer in use. Vacuum and induction
furnaces, which are in limited use, are alloy refining processes for the
production of specialty metals. Only the electric submerged-arc furnace is
significant as far as air pollution is concerned, partially because of its
widespread use and partially because of the copious amount of fume it gen-
erates. This is the only ferroalloy production furnace subject to the NSPS,
and it is still the major method for producing ferroalloys.
Ferrophosphorous is a byproduct of manufacturing phosphorous by the
electric arc furnace process. The emissions from this process are unique
58
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because the product (phosphorous) is condensed and collected from the furnace
exhaust gas stream. The ferrophosphorous is a slag byproduct that is peri-
odically tapped from the furnace.
6.1.1 Electric Submerged-Arc Furnaces
Descriptions of the electric submerged-arc furnace can be found in the ,
90
open literature, and they are reviewed only briefly here. '
Figure 6-1 is a flow diagram of a typical ferroalloy production facility.
The electric submerged-arc furnace in which the smelting takes place consists
of a hearth lined with carbon blocks. Openings in the hearth permit tapping
(or draining) of metal and slag. The steel furnace shell and its hood or cover
components are water-cooled to protect them from the heat of the process.
Car'bon electrodes are vertically suspended in a triangular formation above the
hearth. Normally there are three (sometimes more), and they may be prebaked or
of the self-baking, Soderberg type. These electrodes extend 1 to 1.5 m (3 to 5
ft) into the charge materials. Three-phase current arcs through the charge
materials from electrode to electrode, and the charge is smelted as the elec-
trical energy is converted to heat. Coke and other reducing materials that are
added to the furnace react chemically with the oxygen in the metal oxides to
form carbon monoxide and reduce the ores to base metal. The furnace emits
byproduct carbon monoxide along with entrained particulate matter and metal
vapors.
Power is applied to the furnace on a continuous basis, and feed materials
may be charged continuously or intermittently. Molten ferroalloy and slag are
intermittently tapped into ladles from tap holes in the lower furnace wall.
(Furnaces producing calcium carbide may be intermittently or continuously
tapped.) The melt is poured from the ladles into molds or casting machines.
After the product cools and solidifies, it is crushed, sized, and loaded into
rail cars for shipment. Slag may be disposed of in landfills, but most is sold
for road ballast.
For reduction of atmospheric emissions, the furnaces and tapping stations
are hooded and the off-gases are ducted to a particulate control device (scrub-
ber, fabric filter, or electrostatic precipitator). The configuration of the
hood and/or furnace roof determines whether the furnace is categorized as open,
semisealed, or closed.
59
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6.1.1.1 Open Furnaces--
In the open furnace, a canopy hood through which the electrodes extend is
located 2 to 2.7 m (6 to 8 ft) above the furnace's upper rim. This opening
between the furnace and hood allows large amounts of ambient air to enter the
hood and exhaust system. As the air combines with the hot gases, the carbon
monoxide and most of the organic compounds are burned and the furnace emissions
are diluted and cooled by the ambient air.
This type of furnace is by far the most popular in the United States
because of its product flexibility. However, the large opening around the hood
allows fumes to escape if sufficient draft is not provided. Control equipment
must, of course, be designed to handle the large volumes of gas [8,520 to
18,720 Nm3/MW-h (30,000 to 660,000 scf/MW-h)] inherent in an open furnace
design. Many open furnaces are partially hooded to minimize air intake, and
still allow complete combustion of furnace gases.
6.1.1.2 Semisealed Furnaces—
The semisealed (or mix-sealed) furnace has a water-cooled hood that fits
tightly around the top of the furnace and is vented to an air pollution control
system. The electrodes extejrid down through the hood, and raw materials are
charged through annular gaps around each electrode. Because the seal provided
by the raw material mixture around each electrode is not airtight, fumes may
leak out unless sufficient draft is provided by the air pollution control
system.
Much less outside air is drawn into a semisealed furnace than into an open
furnace, and pollutarlt concentrations are therefore much higher. The resulting
gases are also rich in carbon monoxide. Only four U.S. plants currently use
the semisealed furnace. This type of furnace is not used in the United States
to produce silicon metal or alloys with more than about 75 percent silicon
because it cannot be readily stoked from the outside. -If the high silicon
mixes are not stoked, bridging and resulting pressure buildup from entrapped
gases may occur in the furnace. This condition leads to "blows" (or possibly
explosions) when the gas breaks through the mix or the bridged material col-
lapses. ,
61
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6.1.1.3 Closed or Sealed Furnaces--
This type of furnace utilizes a tight-fitting, water-cooled hood on top of
the furnace, which is vented to an air pollution control system. Raw materials
are fed through separate sealed chutes, and the electrodes penetrate the hood
through seals. The furnace is thus completely sealed and operates under a
slight positive pressure regulated by the fume exhaust system. No outside air
enters the furnace system, and high concentrations of CO (80 to 90 percent) and
particulates are emitted. Exhaust gas volumes reportedly range from 200 to 260
Nm3/MW-h (7060 to 9180 scf/MW-hj, and uncontrolled particulate concentrations
range from 11.5 to 70 g/Nm3 (5.0 to 30.6 gr/scf).4
From the standpoint of air pollution, a closed furnace is the most de-
sirable because all its fumes exhaust through an emission control system and
the total volume of exhaust gas is only 2 to 5 percent of that from an open
furnace. Only two closed furnaces are currently in operation in the United
States; both at one plant, they pfoduce silvery pig iron containing less than
20 percent silicon and smaller amounts of other alloys. Ferroalloys with
higher silicon contents are more difficult to produce in a closed furnace
because they tend to bridge over in the furnace if they are not stoked, and the
closed nature of the furnace makes stoking from the outside much more dif-
ficult. Lack of stoking can lead to explosions from trapped gas.
6.1.2 Process Modifications
In the United States little change has occurred in the process technology
of this industry over the last 5 years. Investigation of beneficiation of feed
materials, operating practices, and possible mechanical modifications to
furnaces continues in an effort to improve operations and minimize emissions.
Generalizations cannot be made regarding design and operation, however, because
a specific evaluation of each furnace type, raw material, and product mix is
required.
The split furnace is an innovative development in furnace design. In
this design the furnace is divided into two separate parts. The upper part is
a relatively narrow ring with flat interior surfaces. This upper ring rotates
more rapidly than the lower furnace portion (e.g., in one design the ring
rotates at 0.1 revolution per hour (rph) while the furnace rotates at 0.01
rph.) This rotation around the stationary electrode has a mixing effect on
62
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the furnace contents and reduces bridging and crust formation problems. A
small (8.5^MW) closed split furnace producing 75 percent FeSi has been operat-
ing in Norway for several years.
A study by Battelle reports that sealed furnaces in Japan are producing
FeMn (high-, medium-, and low-carbon), SiMn, FeSi, high-carbon FeCr, and SiCr.
In these furnaces stoking devices are inserted through seals in the furnace
walls. : . . '
6.2 CONTROL TECHNOLOGY
No basic changes in control technology have occurred in this industry
since promulgation of the NSPS in 1976; however, some changes in control
device design arid operating practices have evolved and have resulted in im-
proved reliability of these devices on ferroalloy furnaces.
6.2.1 Fabric Filter Control System
The fabric filter control system is generally the method of choice for
controlling particulate emissions from the open submerged-arc furnace. This
system is used at 27 of the 31 plants in the United States. The following
discussion is based on generalized information from fabric filter manufacturers
and users contacted for this study. * "' Site-specific conditions will
vary.
The predominant fabric filter system is the pressure type, in which the
fan is on the inlet or dirty side of the filter. These systems exhaust di-
rectly from the top of the baghouse and have no final stack. Cleaning is
accomplished by a reverse-air system, a mechanical shaking system, or a com-
bination of both. Pulse-air cleaning systems are also used at a few instal-
lations. During the cleaning cycle, which is either timed or triggered by
pressure drop and lasts for 1 to 2 minutes, the compartment is isolated from
the gas stream. Because temperatures are in the 177°C (350°F) and higher
range, glass fiber and Nomex fabrics are the most popular, and bag life is on
the order of 1.5 to 2 years. In systems with reverse-air cleaning and glass
fiber bags, air-to-cloth (A/C) ratios are approximately 37 m/h (2 ft/min) as
shown in Table 6-1. In systems with mechanical shakers and Nomex bags, A/C
ratios are a slightly higher 55 m/h (3 ft/min). In systems with pulse-jet
cleaning, A/C ratios are 92 to 130 m/h (5 to 7 ft/min).
• • •: . ' 63
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Fabric weights vary from 170 to 475 gm/m (5 to 14 oz/yd2), and a
typical bag is 28.75 cm (11.5 in.) in diameter and 9.2 m (30 ft) long.
Pressure drops reach about 3.2 kPa (13 in. of water) prior to a cleaning
cycle. When a system is operating properly, it achieves collection efficien-
cies in excess of 99 percent. Broken bags are discarded in landfill areas.
Table 6-1, which presents fabric filter design data obtained from the
recent literature, shows the range of fabric filter applications. Glass
fiber is the fabric cited most frequently. Air-to-cloth ratios usually ran
slightly less than 37.8 m/h (2.0 ft/min). One installation reported that a
higher pressure drop of 3.7 to 4.5 kPa (16 to 18 in. of water) occurred at an
air-to-cloth ratio of 51.0 m/h (2.75 ft/min). The limited data reported on
particulate loading before and after the filter systems showed efficiencies
in excess of 99 percent.
In Europe, pretreatment of the gas stream has been accomplished by the
use of a perforated rotating drum dust agglomerator filled with ceramic
18
balls. The gas stream is first cooled and then passed through the agglom-
erator, where the dust impinges on the ceramic balls. The resulting large
particles are then collected in a fabric filter system, which uses polyester
or acrylic bags and has an air-to-cloth ratio of about 91.3 m/h (5 to 1
ft/min).
6.2.1.1 Fabric Filter System Costs-*
Costs of fabric filter systems depend mainly on the gas flow, type of
fabric (which is related to the operating temperature), and the number of
bags requ" red (related to air-to-cloth ratio). Based on discussions with
p Q - ' .
equipment suppliers ' and generally used engineering factors, the cost of a
fabric filter system can be calculated by the following equation:
Cost> •* = -d ^5'64 + 1<95 x bag cost^ + 47>160
(Jan. 1980)
where: acfm = actual cubic feet per minute
A:C = air-to-cloth ratio, ft/min
Bag cost is expressed in $/ft2 as follows:
Polyester 0.65
Acrylic 0.79
Nomex 1.59
Coated glass fiber 0.74
65
-------
The entire installed cost (including both direct and indirect items) would be
approximately 2.4 times the fabric filter system cost (see Appendix).
A fabric filter system treating 343,000 m3/h (200,000 acfm) and having
an air-to-cloth ratio of 36.6 m/h (2 ft/min) with Nomex bags would cost
$921,000, and the total installed cost would be approximately $2,200,000.
6.2.2 Scrubbers
High-pressure-drop venturi scrubbers have been applied successfully to
a number of ferroalloy furnaces, especially closed and semi sealed furnaces.
19-22
Table 6-2 summarizes reported scrubber data. Pressure drops in the range
of 13.7 to 22.4 kPa (55 to 90 in. of water) make the use of these scrubbers
very energy-intensive, especially when large volumes of gas must be treated.
On the order of 5 to 10 percent of the furnace power requirement may be used
0-3
by the fan motor to draw the gas through the scrubber system.
6.2.3 Other Control Systems
One installation of a sand-bed filter (gravel bed) was reported on a
closed ferrosilicon furnace in Sweden. The furnace utilized a water-cooled
o
hood, and filter system emissions ranged from 400 to 500 mg/Nm (0.17 to 0.22
gr/scf). This concentration would result in a visible plume, but because of
the fairly small quantity of gas exhausted from a closed furnace, this
installation complied with an emission limit of 15 kg/1000 kg of product (30
lb/ton).12
One electrostatic precipitator is in operation on an open furnace in the
United States. This system utilizes gas conditioning with ammonia to enhance
particulate resistivity and increase collection efficiency.
6.2.4 Flares
Flares are used on closed and semisealed furnaces to reduce carbon
monoxide emissions. A flare, which is essentially an open afterburner,
should also reduce combustible particulate and organic matter. Because
actual test data on flares are not available, an approximation of a flare's
ability to reduce organic or particulate matter must be based on afterburner
data.
66
-------
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-se
UI
CD
CQ
Z>
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o
o
LL,
03
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S«> ^^
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^i£ <*
«*£T "l^T
.; in ^.in
kO
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CO
CT»
^*-CM \o ro o in r-
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. o ^r f- a* o ro •
tn - CM • - r— «3- O
O O CM O •—-
^—^ «—• CM •
o o t
f O *• *•
._-. _. j- • oor-
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O CJ
O CTi
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o o o o en o
\O ^ VO O *3" CO
CM in CM in CM ^-
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,
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|| A * r. » r. »
OO C\JCT» CO CM OO CM
0*0 r»-o om oco
^^ f—<— CMr— CMi—
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CM r- i— 'i—
1
1 s
g. 2
O O
67
-------
The combustion efficiency of a flare is primarily a function of tempera-
ture, turbulence, oxygen content, and residence time. Because of the rapid
cooling and dilution inherent in flares, residence time is short (about 0.1
second).*' Temperatures of 581° to 994°C (1078° to 1822°F) have been measured
experimentally in a small pilot plant equipped with flares burning natural
24
gas. ^ Combustion of liquid droplets requires vaporization, and the rate at
which a droplet burns is dependent on its,.s4ze. and,,,thfi temperature. This
relationship is expressed by:
2
. = 29,800 md
where:
t
P
m
d
T
time required for combustion, seconds
partial pressure of oxygen, atmospheres
molecular weight
droplet diameter, cm
temperature, °K
For a 200-molecular-weight hydrocarbon, this formula gives a residence
time of 0.0084 second at 1000 K (1340°F) and an oxygen content of 0.1 atm for
a 50-micrometer droplet. This relationship indicates that more than enough
residence time exists in a flare to vaporize and burn small droplets.
For solids, the combustion relationship is much more complex and cannot
be readily predicted. For a 1 -mi crometer particle, estimated combustion
times range from 0.043 second at 793°C (1460°F) for a coal char to 175 seconds
at 827°C (1520°F) for a soot particle.26 Based on this minimum amount of
data, one can only assume that most solids composed of volatile organic
matter probably would be burned in a flare, whereas inorganic and carbon
particles would not be burned.
6.3 CONTROL OF TAPPING EMISSIONS
Molten ferroalloy is removed from the electric submerged-arc furnace
through a tap hole that is flush with the floor of the carbon hearth. The
tap hole is closed by the manual insertion of a carbon graphite plug after
completion of tapping or by means of a hydraulic or pneumatic mud gun.
Based on an assumed 16.6 m/s (50 ft/s) gas velocity and a 1.7 m (5 ft)
long flame.
68
-------
When the molten metal is ready to be tapped, the tap hole is pierced by
drilling, by use of a single shot pellet fired from a gun-like piece of
equipment, or by oxygen lancing.
The molten ferroalloy passes through the open tap hole to a trough ar-
rangement fixed to the furnace shell and then to runners that direct it to a
ladle or, in some instances, to a runner going directly to a casting bed.
When the ladle is filled with the molten metal, an electric overhead trav-
eling (EOT) crane transports it to the point of deposit, where the metal is
then poured into a bull ladle, a reaction ladle, a pigging machine, or a
shallow cast bed.
Emissions occur during the following:
o
o
o
o
Piercing of the tap hole, if drilling or lancing is used
Tapping at the furnace proper, the runners, and ladle
Transporting in the ladle
Pouring into the bull ladle, reaction ladle, pigging unit, or the
cast bed.
Problems encountered in the control of emissions from retrofit installa-
tions include lack of space to install hooding and still have sufficient room
for operators to do their work; ducting and hooding interference with the
operation of the EOT crane at the tap hole area; and hooding difficulties at
the ladle, especially during pouring, because of floor layout, design, and
existing equipment. Proper planning could prevent most of these problems in
new furnaces.
Since furnace tapping takes 10 to 15 percent of the total cycle time,23
significant emissions can occur. When the molten metal is poured into a bull
ladle, emissions are very high but of a short duration; whereas, when the
metal is poured into a reaction ladle, emissions are both significant and of
rather long duration. Emissions are also high but of a short duration when
the metal is poured from a ladle to a casting bed; however, they are both
higher and prolonged when the molten metal goes directly from the furnace to
an adjacent cast bed during tapping.
69
-------
Several possible measures are available for reducing emissions during
tapping in new furnaces.
0 Hooding could be designed to minimize emissionsi instead of in
arrangement in which an EOT crane transports the ladle, a ladle car
on tracks or a rubber-tired unit with a ladle tilting device
operating under a canopy tunnel enclosure could be used to trans-
port the molten metal to the bull ladle or casting bed; casting
beds could be designed to eliminate crosscurrents and emissions
could be collected overhead; and reaction ladle operations could be
designed to take place in an enclosed building and emissions could
be collected overhead. In each instance, the control equipment
would be a fabric filter system.
0 It may be possible to enclose and vent the tap area around each
furnace and to use pendant-operated EOT cranes to service the area,
independent of the main EOT cranes. Airflow would be 70.7 to 94
m3/s (150,000 to 200,000 cfm).
0 Another possible control method is the use of a telescopic emission
capture device (see Figure 6-2).
0 The use of an air curtain in the tapping area.would permit the
crane access to the tap hole area, runners, and ladle (see Figure
6-3). Airflow would be 16.5 to 21.2 m3/s (35,000 to 45,000 cfm).
0 Ladles could be equipped with covers, but this would increase
handling time and maintenance.
0 The use of a vermiculite slag blanket would minimize emissions in
transportation, but it would also create pouring problems.
0 A verticle takeoff on the hood over the tapping area could help to
alleviate fugitive emissions.
0 A total building enclosure with an overhead collection system would
also minimize fugitive emissions to the atmosphere, but would not
achieve compliance with the NSPS since visible emissions are
determined at the hood.
70
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FAR SIDE- ID FAN
AUX HOIST DRUM
TRANSFER
DUCT
SPLIT RUBBE
COVER OVER
TRANSFER DUCT
TELESCOPIC CAPTURE
DUCT (SIMILAR TO
STEEL HILL SOAKING
PIT CRANE)
TRANSFER DUCT
TO FAN
AND BAGHOUSE
(CAN BE MOUNTED
OVERHEAD UNDER
THE ROOF TRUSSES)
BLDG
COLUMN
CAPTURE HOOD
FIXED TO
SPREADER BEAM
HOIST
DRUM
TRANSFER
DUCT
TROLLEY
WALKWAY 1
•
B0
n
TELESCOPIC
CAPTURE
DUCT
E.O.T.
GIRDER
Figure 6-2. Ladle/EOT crane .fugitive emission collection system.
71
-------
ELECTRODES-
EXHAUST TO
CONTROL EQUIPMENT
ELECTRIC SUBMERGED ARC FURNACE
OPENING FOR
CRANE CABLES
AIR IN
PICKUP
AIR AND
AIR FLOW -FUGITIVES OUT
PATTERN
Figure 6-3. Air-curtain fugitive control system.
72
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REFERENCES FOR SECTION 6
1. Draft Preprint from F. J. Schottman, U.S. Department of the Interior, to
PEDCo Environmental, Inc., April 7, 1980.
2. Dealy, J. 0., arid.A. M. Killin. Engineering and Cost Study of the
Ferroalloy Industry. U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina. EPA-450/2-74-008, May 1974. p. VI-48.
3. Background Information for Standards of Performance: Electric Sub-
merged-Arc Furnaces for Production of Ferroalloys, Volume 1: Proposed
Standards. U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina. EPA-450/2-74-018a, October 1974. p. 7.
4. Denizeau, J., and H. D. Goodfellow. Environmental Legislation Approaches
and Engineering Design Considerations for Ferroalloy Plants. In:
Proceedings of the Fourth International Clean Air Congress (Paper,
VI-20). Japan. May 17-20, 1977.
5. Engineering/Mining Journal. October 1978. pp. 45, 51.
6. Mobley, C.'£., and A. 0. Hoffman. A Study of Ferroalloy Furnace Product
Flexibility. Battelie Columbus Laboratories. NTIS No. PB-247-273/657,
July 1975. 83 pp.
7. Telecon. Hoffman, C., W. W. Criswell Co,s Inc., with M. Giordano, PEDCo
Environmental, Inc. Fabric Materials for Baghouses. May 9, 1980.
8. Telecon. R. F. Morand, Wheelabrator-Frye, Inc., with L. Yerino, PEDCo
Environmental, Inc., May 29, 1980. Fabric Filter Control Systems.
9. Telecon. G. Applewhite, American Air Filter Co., with L. Yerino, PEDCo
Environmental, Inc., May 30, 1980. Fabric Filter Control Systems.
10. Telecon. R. Scherrer, Midwest Carbide Co., with R. Gerstle, PEDCo
Environmental, Inc., June 6, 1980. Emission Control Systems.
11. Boegman, N. Ferro Alloy Furnace Emission Control in South Africa -
Policy, Progress, Problems, and Cost. Department of Health, Government
of South Africa, Pretoria, South Africa. 4pp. May 16-20, 1977.
12. Lomo, A. Pollution Problems with Electric Reduction Furnaces in the
Ferroalloy Industry. In: Proceedings INFACON. 1974. pp. 251-257.
73
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13. Payton, R. N. Innovations in Ferroalloy Baghouse System Design.
Journal of the Air Pollution Control Association, 26:18-22. January
14. Bettanini, C. Four Years' Experience with Bag Filters for Ferrosilicon
Fumes. Filtration and Separation. July/August 1977. pp. 398-402.
15. Pollution Control, Materials and Gas Reuse and Features of Big New
Quebec Plant. Modern Power and Engineering, May 1974. 4 pp.
16. Meredith, W. R. Operation of a Baghouse Collecting Silica Fumes. In-
Electric Furnace Proceedings, Air Pollution and Environmental Control
Equipment and Processes. 1972. pp. 69-71.
17. The Fabric Filter Newsletter. No. 17. March 1977. pp. 9 & 10.
18. Telecon. Bentner, H. P. Interal Corp.t with L. Yerino, PEDCo Environ-
mental, Inc. Luhr EKU System. May 23, 1980.
19. Ratzlaff, R. 6. Construction and Operation of a New Ferromanganese
Facility. Union Carbide. 4 pp. 1974.
20. Field Test of a Venturi Scrubber in Russia. Presented at Second Fine
Particle Scrubber Symposium, New Orleans, May 2, 3, 1977. 8 pp.
21. Sherman, P. R., and E. R. Springman. Operating Problems with High-
Energy Wet Scrubbers on Submerged-Arc Furnaces. Union Carbide Corp ,
Niagara Falls, New York; Marietta, Ohio. Presented at AIME Furnace
Conference, Chicago, Illinois, December 1972. 20 pp.
22. Horibe, K. A Completely Closed Electric Furnace for the Production of
75 Percent Ferrosilicon. In: Proceedings INFACON. 1975. Johannes-
burg, South Africa, pp. 91-98. 1975.
23. Trip Report. To Union Carbide Corporation Plant, Marietta, Ohio. By
PEDCo Environmental, Inc. June 5, 1980.
24. Straitz, J. F. Flaring for Gaseous Control in the Petroleum Industry
Paper 78-58.8, presented at the 1978 Annual Meeting of the Air Pollution
Control Association. June 1978. p. 8.
25. Rolke, R. W., et al. Afterburner Systems Study. National Technical
Information Service. PB212560, August 1972. p. 196.
26. Reference 25, pp. 197-198.
74
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SECTION 7
CONCLUSIONS
7.1 INDUSTRY GROWTH
Total domestic production of ferroalloys has remained fairly static
since promulgation of the NSPS in 1976. Because no new furnaces have been
built or modified, no furnaces are currently subject to the NSPS. The
industry's annual growth rate has declined from 1.5 percent to zero. Two
large plants (one at Brilliant, Ohio, and the other at Sheffield, Alabama)
have been shut down and furnaces at many plants have been shut down and some
have been dismantled. In 1971, 158 electric arc furnaces were in operation,
145 for ferroalloy production and 13 for calcium carbide production.
Currently, approximately 89 are producing ferralloys and 7 are producing
calcium carbide. No new furnaces are expected to begin operation in this
country in the next few years. This decline in the industry has resulted
from a rapid increase in imports ancl the fairly static condition of the
domestic steel industry.
Another trend in this industry is the purchase of U.S. plants by foreign-
based companies. Approximately 50 percent of the capacity of the plants in
the United States are now owned by or being sold to foreign companies.
7.2 PROCESS CHANGES
No new process technology has been introduced to this industry, and the
basic technology has remained unchanged. The electric submerged-arc furnace
is still by far the predominant method for producing ferroalloy. The metal-
othermic and electrolytic processes are still used for speciality alloy
production, but they account for only about 5 percent: of total alloy produc-
tion.
75
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Advances in furnace design include the split rotating furnace, which
minimizes buildups and bridging of the mix and thereby reduces the amount of
external stoking required. This design allows the furnace to be more
enclosed than an open furnace and thus decreases fugitive emissions around
the hood. No split rotating furnaces are currently used in the United
States.
7.3 CONTROL EQUIPMENT
No innovations in control equipment or control systems have been devel-
oped, but operation of the existing equipment has improved as experience has
been gained. Fabric filter systems are the most common means of particulate
control. When properly maintained, they can reduce emissions to a level that
complies with applicable state regulations. In this country, high-pressure-
drop scrubbers are used mainly on semisealed and closed furnaces. These
devices can reduce particulate emissions by more than 99 percent and can
achieve emission levels that meet applicable regulations. In addition,
scrubbers reduce organic emissions by 16 to 97 percent.
Flares are used on closed and semisealed furnaces to reduce carbon
monoxide emissions. They probably also reduce organic and combustible
particulate emissions, but quantitative data on their efficiency are not
available.
An electrostatic precipitator is used effectively on one open furnace in
this country.
Control of fugitive particulate emissions generated by furnace tapping,
ladle transfer, and casting continues to be a problem on existing furnaces
because it is difficult to retrofit adequate hooding systems. This is a
site-specific problem that does not require new technology. Such control
could be designed into a new installation more easily than it can be retro-
fitted into an existing one.
7.4 EMISSIONS
New data on emissions from ferroalloy furnaces have been gathered as
part of EPA's environmental assessment studies. These studies included tests
to determine the amount of particulates, organics (including polynuclear
76
-------
aromatic hydrocarbons)> and trace metals in the emissions. Also, a number of
tests were conducted on existing furnaces to determine whether they were in
compliance with state regulations.
7.4.1 Organic Emissions
Of prime interest among the new data are those on organic emissions,
particularly POM. Quantitative data obtained to date are very limited, and
only rough estimates of industrywide organic emissions can be made. These
are shown in Table 7-1.
TABLE 7-1. ESTIMATED ORGANIC EMISSION RATES AFTER CONTROL
Furnace type
Open
Semi sealed
Closed
Control device
Fabric filter
Scrubber
Scrubber
• • , •
Scrubber
Total organic
kg/MW-h
0.20
0.29
0.15
0.01
emission,3
(Ib/MW-h)
(0.44)
(.0.63)
(0.33)
(0.022)
Before any further reduction by flares.
When these emission rates are multiplied by the respective furnace capacities,
the estimate of total annual organic emissions from submerged-arc furnaces is
2220 Mg (2440 tons), based on 70 percent utilization. Data presented in
Section 5 on polynuclear organic matter show that POM compounds represented
from 8.3 to 75 percent of the total organic emissions after a scrubber and
before the flare. The single test on a semisealed furnace after a scrubber
showed that BaP accounted for 0.84 percent of the organic emissions.
The ground-level ambient air impact can be estimated by an atmospheric
dispersion model. Table 7-2 presents ground-level concentrations of organics
obtained by utilizing EPA's PTDIS dispersion model for selected 20-MW plants
at a windspeed of 4.4 m/s (10 miles/hour) and a Class C atmospheric stability.
These estimates show that the highest levels occur 1 to 2 km from the stack
and that an open furnace with a scrubber represents the worst case with 24-
' ' • 3 •
hour concentrations of 1.1 to 1.6 ug/m . This is because the scrubber water
lowers the stack gas temperature, which in turn decreases dispersion.
77
-------
U-
oo
1—1
2:
•=c
cu
o
u_
o
2E
O
UJ LU
O O
D;
_] I
a CM
cs
Q
LU
oo
UJ
CM
uj
_ i
CO
10 3.
c-*:
o u
rd
>
i
> 0)
- u
) >r«
1 QJ
> -a
a)
CL
cu
o
re
c:
i-
u_
r-oo
«JCM
o o
0 0
•— o
o o
CO CO
00
IOCO
o o
0 0
§§
0 0
CO
0
CO
o
~
o
LO
CO
o
S.
u
IT) r—
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•d- -a-
•— 0
o o
CM C3
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CO O
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00
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CD
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CO
CO
CD
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CO
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o
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-------
Ground-level concentrations of other compounds, can be estimated by a
direct proportion of the values in Table 7-2. Thus, if BaP comprises 0.8
percent of the total organic emissions from a semisealed furnace, the average
24-hour ground-level concentration would be: (0.8% x 0.64 yg/m ) = 0.005
"3 '••',' ' '
yg/m at a point about 2 km from the stack.
None of the ferroalloy plants practices direct control of organic
emissions. Scrubbers used for particulate control also reduce organic emis-
sions and would be expected to reduce POM compounds by a similar amount. The
POM compounds thus end up in the wastewater stream, where they could cause a
disposal problem. Flares used for CO control would also be expected to
reduce organic and POM emissions; however, data pertaining to the extent of
control are lacking. The use of open furnaces, in which combustion of CO and
other combustible matter takes place in the furnace, minimizes organic emis-
sions.
7.4.2 Trace Metal Emissions
Section 5 presented limited data on emissions of trace metals. The major
metallic emissions are composed of oxides of the product alloys produced in the
furnace. The trace element emissions, which are related to impurities in the
ores, may Vary widely. Ferroalloy plants with high efficiency particulate
controls as required by most state and local regulations are not generally
major sources of lead. Lead emissions are subject to the national ambient air
... - - 3 ' • - • • ' - .
standard of 1.5 yg/m .
Cadmium, arsenic, and copper compounds are also emitted by ferroalloy
furnaces. Again emission data are sparse and highly variable. Table 7-3
presents estimated emissions of trace metals that are or may be designated as
hazardous pollutants under Section 112 of the Clean Air Act.
79
-------
TABLE 7-3. ESTIMATED EMISSIONS OF HAZARDOUS TRACE
METALS. AFTER CONTROL
Metal9
Arsenic
Beryllium
Cadmi urn
Copper
Mercury
Leadd
Estimated Emissions
mg/MW-h
62
0.02
17C
. 8.5C
4
2.7
g/24 hoursb
30
0.01
8.2
4.1
1.9
1.3
Beryllium* mercury,and arsenic are_ currently listed under Section 112 of the
Clean Air Act. The other metals are being considered for possible
designation as hazardous pollutants.
For a 20-MW furnace.
Based on uncontrolled emission measurement and assumed 99% reduction
in a scrubber.
A
Designated as a criteria pollutant, not a hazardous pollutant.
These data show that mercury and beryllium emissions are approximately 1.9
and 0.01 g/day respectively. These are fairly low levels compared with the
allowable emission of 10 g/day for beryllium and 2300 g/day for mercury for
other processes as designated in Section 112 of the Clean Air Act. Lead
emissions are also relatively low.
7.5 SOURCE TESTING METHOD EVALUATION
The Standards of Performance for new ferroalloy facilities specify the
testing methods for measurement of the emissions. The testing methods
described (specifically Method 5) have been used successfully on wet scrubber
and enclosed fabric filters.
Several precautions have been taken by various testing teams to ensure
accurate data collection and safety of sampling personnel. For example, for
sampling at the inlet to a control device, the use of a cyclone of large
volume (200 ml) is recommended to minimize the need for changing plugged
filters during the test run. This allows uninterrupted sampling of integral
80
-------
furnace cycles.. If a filter change is necessary, it should be made at the
point in the furnace cycle where the run began.
High carbon monoxide content is inherent in the production of ferro-
alloys in sealed and semi sealed furnaces. The testing method states that
when the CO content is greater than 10 percent by volume, the heating systems
specified in Method 5 should not be used. Electrical-resistance heating
systems can create an explosion hazard in high CO content gases. Although
the absence of probe and filter heating systems may not bias the results of
tests on fabric filter control devices, it will bias the results of tests at
the outlet of wet scrubbing systems because of condensation. Use of a steam
, •. '.•••.' ,1.:1 ' . •.....••. • 4
heating system is recommended when sampling the exit from wet collectors.
The probe and filter portions of the sampling system should be heated to 120°
+14°C (250d + 25°F), as specified in Method 5.
As a safety precaution, the vacuum pump should be properly grounded to
' 3 ' ' •
minimize the chance of sparking. It is also recommended that a length of
large diameter tubing be attached, to the exit end of the meter box orifice.
This tubing should be vented away from al1 personnel, to minimize the health
45
hazards associated with high CO content in the gas stream. ' Before sam-
pling begins, the orifice should be calibrated with the length of tubing
attached, to insure isokinetic sampling conditions.
In stacks with high CO contents, high negative static pressures, and
high temperatures [540°C (1000°F)], an air-tight seal should be provided
around the, probe. In one case, an improper seal reportedly caused air to
leak into the stack and ignite the gas.-
In addition to EPA Method 5„ Level 1 Source Assessment Sampling Systems
(SASS trains) have been used to characterize emissions from ferroalloy fur-
naces.4'6 Qas chromatography and electron capture have been used successfully
for the determination and quantification of reduced and oxidized sulfur com-
pounds4, and gas chromatography by flame ionization has been used for the
' -• • -••••' ' ' . ' • .. ' 4
determination and quantification of hydrocarbon compounds.
The CO content of the gas stream associated with the production of
ferroalloys has been measured by EPA Method 3 procedures, with minor diffi-
culties. A standard Orsat apparatus with the volumetric capacity to measure
CO quantities in the 30 to 80 percent range should be used for testing sealed
furnaces.
81
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Testing open fabric filters presents difficulties because an enclosed
duct is not available and a complete traverse of the open area is impossible.
A Specific test plan must be developed for each site. Erection of a tem-
porary stack on one module of the fabric filter system (to facilitate mea-
surement of particulate concentrations) and measuring total gas flow at the
fabric filter inlet have been used to obtain emission rates:
.7,8
the amount
of ambient air induced into a fabric filter system .has beeji. estimated by
" 7 : •'.."• •':• '•'-• v $''• ." ?';'
making heat balances around the system. Measurements after flares have not
been attempted because of inaccessibility and the unconfined nature of a
flare.
82
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REFERENCES FOR SECTION 7
1. Dealy, J. 0., and A. M. Killin. Engineering and Cost Study of the
Ferroalloy Industry. U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina. EPA-450/2-74-00&, May 1974. p. IV-3.
2. Lomo, A. Pollution Problems with Electric Furnaces in the Ferroalloy
Industry. In: Proceedings INFACON. pp. 251-257. 1974.
3. Telecon. M. Bockstiegel, PEDCo Environmental, Inc., to J. Gluts, Mogul
Corporation, May 2, 1980. Source Testing of Ferroalloy Production
Facilities.
4. Telecon. M. Bockstiegel, PEDCo Environmental, Inc., to D. Harris,
Monsanto, May 13, 1980. Source Testing at Ferroalloy Facility in
Canada.
5. Telecon. M. Bockstiegel, PEDCo Environmental, Inc., to R. Schab, Beling
Engineering Consultants, May 16, 1980. Source Testing of Ferroalloy
Production Facilities.
6. Westbrook, C. W., and D. P. Daugherty. Draft Environmental Assessment
of Electric Submerged Arc Furnaces for Production of Ferroalloys. U.S.
Environmental Protection Agency, Contract No. 68-02-2630. March 1980.
7. Telecon. M. Bockstiegel, PEDCo Environmental, Inc., to J. Fox, Frederick-
sen Engineering Co, May 15, 1980. Source Testing of Open Baghouses.
8. Telecon. M. Bockstiegel, PEDCo Environmental, Inc., to H. Rogers,
Environmental Management, May 15, 1980. Source Testing of Ferroalloy
Production Facilities.
83
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SECTIC-N 8
RECOMMENDATIONS
8.1 CHANGES IN REGULATIONS
No changes in particirtate emissions regulations are recommended at this
time. Limited additional test data for determination of compliance with State
emission regulations have indicated particulate emissions also comply with the
NSPS. Regulations in other countries are generally less restrictive than U.S.
regulations, except those for closed furnaces.
Visible emissions from control equipment vents ate usually in compliance
with the NSPS requirement of 15 percent or less opacity, except during
malfunctions. Most plants are also in compliance with existing state regu-
lations. Visible emissions from tapping are a problem on existing furnaces,
but technology available for hooding and control of new furnaces should
enable them to comply with the NSPS. No change in the visible emission
levels is recommended.
Flares are used on streams with high CO content, and there is no need to
change the CO emissions limit.
8.2 AREAS OF FURTHER STUDY
I
Although emissions of many organic compounds have been identified from
open, closed, and semisealed furnaces, data are currently insufficient to
determine the magnitude and impact of these emissions; especially after
control devices. It is therefore recommended that tests be performed on open
furnaces equipped with fabric filter control systems to determine the quantity
of the organic and especially POM compounds in the! exit gas stream and how
effectively they are controlled by fabric filtration systems. A determination
of how much a flare reduces organic and POM concentrations will be necessary
for an assessment of emissions from closed and semiclosed furnaces.
84
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APPENDIX
COSTS FOR FABRIC FILTER SYSTEMS
Data required:
Gas flow and gas temperature to baghouse
Type of ferroalloy produced
A/C ratio
AP = 13 in. of water
Reverse air and insulated baghouse
Baghouse cost:
x acfm to baghousex
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4. Installed costs:
Direct
Fabric filters, fans, and motor
Instrumentation and controls
Electrical (no transformers)
Piping
Insulation
Painting
Site preparation
Foundations
Structural work
Indirect
Engineering
Contractor's fee
Field expenses
Freight
Offsites
Taxes (if not exempt)
Allowance for startup, etc.
Spares
Contingency
Escalation
Interest during construction (12%/yr)
Material
and
equipment^
x
O.Olx
0.05x
O.Olx
Supplied/
baghouse
O.OOlx
O.OOSx
O.Olx
O.Olx
1.096x
0.1 Ox
O.lSx
0.05x
0.04x
0.02x
0.025x
0.015x
0.02x
0.06x
0.075x
0.162x
0.717X
Installation
0.4x
O.OOSx
0.05x
O.Olx
0.05x
0.009x
O.OOBx
O.Olx
O.Olx
0.584x
Total installed cost = 2.397x. [Total installed cost does not
include ducting to the baghouse or to the stack nor the stack cost.
(Note: Most of ducting and stack costs would be part of the furnace
costs). Dust removal would be accomplished by plant's vehicle No
costs for disposal area.]
86
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5. Annual Operating Costs:
Utilities ,
a. Electricity:
I.D. fan: 0.00314 x 0.746 x baghouse acfm x 8760 x 0.035
= 0.6823 x acfm = $
Reverse: 0.0614 x 0.00314 x 0.746 x acfm x, 8760 x 0.95
x 0.2 x 0.035 =0.0084 x acfm = $
11 x 0.746 x acfm x 0.25 x 0.035 x 8760
Screw conv.:
6.00143 x acfm
b. Operations
1. Labor
2. Supervision
c. Maintenance
440,000
1 man/shift x $8.50/h x 8760 = $ 74,500
15% of labor = 11,200
1 . Labor
d. Overhead
1. Plant
2. Payroll
e. Fixed costs:
Depreciation
1 man/shift x 9.00 x 8760 = 78,840
P
acfm (baghouse) Y bag cost $/ft _
A/C ratio * 2 ~
: 0.1 (b.l + b.2 + c.l) = 16,500
0.5 (b.l + b.2 + c.l) = 82,270
0.2 (b.l + b.2 + c.l) = 32,908
100
equip. 1ife (15 yr)
Interim replacement
Insurance
Taxes
Capital cost
= 6.67%
= .35%
.30%
= 2.00%
=12.00%
21.32%
0.2132 x total installed cost
87
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f. Dust removal
1 truck per day - 2 h/day - captive truck
2 (8.50) x 1.9 x 365 x .95
Total annual operating cost
is total of all items
= $11,200
$
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TECHNICAL REPORT DATA
(I'lcau- rcaJ Instructions on ill? mem be fun i am/ilt linn i
1 (REPORT NO.
EPA-450/3-80-41
2.
4. TITLE ANDSUBTITLE
Review of New Source Performance Standards for
Ferroalloy Production Facilities
7 AUTHOR(S) ..'.,„•
R. w. Gerstle, W. F. Kemrier, and L. V. Yerino
9. PERFORMING ORGANIZATION NAME At>
PEDCo Environmental, Inc.
11499 Chester Road
Cincinnati, Ohio 45246
JD ADDRESS
12. SPONSORING AGENCY NAME AND ADDRESS
DAA for Air Quality Planning and Standards
Office of Air, Noise, and Radiation
U.S. Environmental Protection Agency
Research Triangle Park, M.C. 27711
3 RECIPIENT'S ACCESSION NO.
5 REPORT DATE
December 1
980
6 PERFORMING ORGANIZATION CODE
e. PERFORMING ORGANIZATION REPORT NO.
P/N 3450-10
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
Contract No. 68-02-3173
Assignment 10
13. TYPE OF REPORT AND PERIOD COVERED
Draft Final
14. SPONSORING AGENCY CODE
EPA/200/04
IE SUPPLEMENTARY NOTES
OAQPS Project Officer: George B. Crane, MD-13, (919)541-5301
16 ABSTRACT
The purpose of this study was to determine if any revisions are needed in
the NSPS for Ferroalloy Production Facilities. Information was obtained from
manufacturers, regulatory agencies, and the literature.
In 1979, ferroalloy production was 1.6 Tg (1,830,000 tons), which represents
a 21.5 percent decline since 1971. The number of electric submerged-arc furnaces
has also decreased from a total of 158 to 89 for ferroalloys and 7 for calcium
carbide. No new furnaces have been built since 1974, and none are subject to
the NSPS. Tests made to determine compliance with state regulations showed
particulate emission rates in the range of 0.07 to 0.2 kg/MW-h (0.10 to 0.44
lb/MW-h). Fabric filter control systems are widely used on open type furnaces,
and high-pressure-drop scrubbers are used on semisealed and closed furnaces.
Flares are used to reduce CO emissions. Limited organic emissions data showed
a range of 0.15 to 0.29 kg/MW-h (0.33 to 0.63 Ib/MW-h) prior to the flare.
Because of lack of growth and an absence of new technology, no changes in
the NSPS are recommended.
17.
a. DESCRIPTORS
Air pollution, regulations
Ferroalloys
18. DISTRIBUTION STATEMENT
Unlimited
KEY WORDS AND DOCUMENT ANALYSIS
b.lDENTIFIERS/OPEN ENDED TERMS
New Source Performance
Standards (NSPS)
Iron and Steel Industry
19. SECURITY CLASS f This Report)
Unclassified
2O. SECURITY CLASS (This page)
Unclassified
c. COSATI Field/Group
13B
11F
21. NO. OF PAGES
96
22. PRICE
EPA Form 2220-1 (t-73)
89
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