ENVIRONMENTAL PROT*mON AGENCY
OFFICE OF ENFORCEMENT
EPA-330/2-77-010
Evaluation of
Zinc Fuming Furnace Fugitive Emissions
Bunker Hill Lead Smelter
Kellogg, Idaho
NATIONAL ENFORCEMENT INVESTIGATIONS CENTER
DENVER.COLORADO
APRIL 1977
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Environmental Protection Agency
Office of Enforcement
EPA-330/2-77-010
EVALUATION OF ZINC FUMING FURNACE FUGITIVE EMISSIONS
BUNKER HILL LEAD SMELTER
KELLOGG, IDAHO
April 1977
National Enforcement Investigations Center
Denver, Colorado
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CONTENTS
I INTRODUCTION 1
II SUMMARY AND CONCLUSIONS 3
Compliance Status 3
Company Approach 3
Planned Modifications 4
Maintenance and Operation 4
Charging Emissions Controls 4
Process Modifications 5
Cost Estimates 5
III RECOMMENDATIONS 6
IV PROCESS DESCRIPTION 7
Lead Smelter 7
Zinc Fuming Plant 9
V APPLICABLE REGULATIONS 27
Regulation F - Control of Fugitive Dust 27
Regulation H - Control of Particulate
Emissions From Industrial Processes 28
VI PARTICULATE COLLECTION AND CONTROL 30
Operation and Maintenance 30
Process Modifications 32
Charging Emissions Collection 34
Charging Emissions Control 39
VII COST ANALYSIS 42
VIII RELATED INDUSTRY EXPERIENCE 45
ASARCO - Montana 45
ASARCO - Texas 54
REFERENCES 61
BIBLIOGRAPHY 62
APPENDICES
A 113 Notice of Violation
B Idaho Air Regulations F and H
C Calculations
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TABLES
1 Typical Operating Data for the Zinc Fuming Furnace . . 12
2 Design Parameters and Specifications for Slag
Granulating Pit Scrubber 17
3 Design and Actual Parameters for the Zinc
Oxide Baghouse 21
4 Estimated Mass Rates for the Zinc Fuming Plant .... 26
5 Allowable Rate of Emission Based on Process
Weight Rate 29
6 Alternatives for Providing Appropriate Ventilation
of the Zinc Fuming Furnace Charging Area 37
7 Alternatives for Collecting and Controlling
Particulate from Zinc Fuming Furnace Charging
Emissions 40
8 Summary of Costs for Alternatives to Reduce Zinc
Fuming Furnace Fugitive Emissions 43
9 Operating and Design Information - ASARCO,
Montana Zinc Fuming Plant 49
10 Operating and Design Information - ASARCO,
Texas Zinc Fuming Plant 58
FIGURES
1 Simplified Process Flow Sheet 8
2 Process Flow Diagram 10
3 Physical Arrangement of Zinc Fuming Furnace and
Waste Heat Boiler (1957) 13
4 Fan Characteristic Curves for Zinc Fuming Plant
Stack Fan 33
5 Elevation Drawing Showing Location of Existing
Charge Area Hood for the Zinc Fuming Plant 34
6 Sketch of Hooding Arrangement for Zinc Fuming
Furnace Charge Area (Alternative A) 33
7 ASARCO, East Helena, Montana -
Lead Smelter Plant Flow Sheet 46
8 ASARCO, East Helena, Montana -
Zinc Fuming Plant Flow Sheet 48
9 Process Flow Diagram for Lead and Zinc Dept.,
ASARCO-E1 Paso Smeltering Works 54
10 Process Flow Diagram for Zinc Fuming Plant,
Lead Dept., ASARCO-E1 Paso Smeltering Works .... 57
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I. INTRODUCTION
The Bunker Hill Company, a subsidiary of Gulf Resources and Chemical
Corporation, operates a mine flotation mill, a lead smelter and a zinc
smelter at Kellogg, Idaho. Lead and zinc concentrates produced from the
mill and from other foreign and United States mills are charged to the
custom lead and zinc smelters for processing. Besides refined lead and
zinc, the Company produces black and clear sulfuric acid, high-purity
silver, antimonial (hard) lead, zinc oxide, dore metal (silver-gold
alloy), copper matte and cadmium sponge at this location.
On or about September 22, 1976, the Bunker Hill Company was issued
a Section 113 (Clean Air Act) Notice of Violation [see Appendix A]
addressing several areas of the lead smelter, including the blast furnace,
sintering process area, zinc fuming plant, silver retort and lead refinery.
Since then, the Company has proceeded with corrective action on all
areas with the exception of the zinc fuming plant charge area for which
the Company was to provide adequate exhaust capability to an appropriate
control device. The Company has refused to comply with control require-
ments for the zinc fuming furnace charging emissions, stating that these
emissions were too insignificant to warrant the cost involved, estimated
by the Company to be $300,000.: As a result, Environmental Protection
Agency (EPA) Region X asked the National Enforcement Investigations
Center (NEIC) to analyze the availability and feasibility of technology
for the Bunker Hill zinc fuming plant to comply with the fugitive emis-
sion regulation (Idaho Air Pollution Regulation F) and the process
weight regulation (Idaho Air Pollution Regulation H). Region X also
asked the NEIC to determine the capital and operating costs associated
with any recommendations.
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In August 1976, the NEIC inspected the Bunker Hill lead smelter and
requested further information from the Bunker Hill Company. This infor-
mation was provided by the Company during October 1976 with subsequent
data requested and provided in January and February 1977. An additional
visit to the smelter was made during February 1977. To obtain further
background information, the NEIC conducted inspections of the zinc
fuming furnace operations at ASARCO lead smelters in East Helena, Montana
and El Paso, Texas in 1976-77.
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II. SUMMARY AND CONCLUSIONS
A technical evaluation and cost analysis of the zinc fuming plant
at the Bunker Hill lead smelter was conducted. The evaluation reviewed
means by which the emissions from the plant could be brought into com-
pliance with Idaho Air Regulation H (process weight) and Regulation F
(fugitive dust). The results of the review are as follows.
COMPLIANCE STATUS
The zinc fuming plant does not comply with Idaho particulate
Regulation F. Compliance with Regulation F is interpreted to require
installation of a more effective charge area hood and subsequent gas
treatment in a particulate removal device. The plant does comply with
Regulation H, if consideration is given only to those particulate sources
for which Method 5 determinations were made.
COMPANY APPROACH
Based on information provided by the Bunker Hill Company personnel,
it is believed that the Company was not sufficiently thorough in its
evaluation of zinc fuming furnace charging emission controls. Their
limited review of the problem did not adequately evaluate possible
process and control system alternatives. Furthermore, the Company's
statement that charging emission controls are not practical contradicts
practices at other lead smelters. Of the two other zinc fuming opera-
tions known to be in existence in the United States, one is currently
using charging emission controls while the other intends to have con-
trols by late 1977.
Code of Federal Regulations, Title 40, Part 60.
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PLANNED MODIFICATIONS
Currently, the Company is expanding the main lead smelter baghouse
capacity, increasing the zinc fuming plant stack fan capability and
rebuilding the zinc oxide baghouse. The latter two modifications will
cause a small reduction in the existing fuming plant fugitive emissions.
However, there has been no apparent attempt to expand any of these
modifications into a comprehensive plan which would significantly reduce
fugitive emissions.
MAINTENANCE AND OPERATION
There are some modifications which can be made to existing main-
tenance and operating practices which could reduce the fugitive emis-
sions. The most readily applicable of these includes more frequent
inspections of and adjustments to, the waste heat boiler lance doors.
It is significant, however, that during EPA inspections, parts of both
the waste heat boilers and the zinc fuming furnace were observed to be
under positive pressure. Since these units were designed for negative
pressure, no amount of maintenance would completely eliminate door
leakage. Maintenance and operating modifications developed during this
review could be employed with little or no associated cost.
CHARGING EMISSIONS CONTROLS
Control of charging emissions at the zinc fuming plant can be
accomplished by installing effective fume collection hoods which would
vent to an appropriate particulate removal device. Appropriate par- .
ticulate removal could be provided by expanding the present zinc oxide
baghouse or by installing a new baghouse. The installed cost of con-
trols including the expansion of the existing zinc oxide baghouse is
estimated by NEIC at $320,000, while the cost of controls utilizing a
new baghouse is estimated at $370,000. Annual operating costs are
estimated as $75,000 and $83,000, respectively.
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It may also be possible that the modified main lead smelter bag-
house could be used for treating zinc fuming charging emissions. However,
the Company has expressed concern that this baghouse when modified will
marginally handle planned gas streams. Consequently, the use of the
main baghouse for the zinc fuming furnace charge emissions must be
reviewed after the modified main baghouse is operating. The installed
cost using the main baghouse for charging emissions is estimated by NEIC
to be $57,000, assuming very few additional changes to the baghouse are
necessary. The added annual operating cost would be $14,000.
PROCESS MODIFICATIONS
Various process modifications, in addition to or in conjunction
with charging emission controls, can be made to increase available draft
in the zinc fuming furnace. These include installing an additional
stack fan and expanding the existing baghouse. The modifications alone
would not assure compliance with fugitive emission regulation, but would
reduce charging emissions and thereby reduce the extent of control and
above-estimated costs for charging emission controls. The estimated
installed costs developed by NEIC for these modifications are: new
stack fan —$64,000, and an expanded zinc oxide baghouse — $195,000.
Annual operating costs are expected to be: new stack fan — $22,000,
and an expanded zinc oxide baghouse ~ $52,000.
COST ESTIMATES
All cost estimates developed in this study should be considered as
preliminary (+30%) estimates. Installed costs include engineering,
installation and equipment costs, but do not include costs associated
with production time lost during installation. Annual operating costs
include direct costs, such as maintenance, replacement parts, etc., as
well as indirect costs incurred in depreciation, taxes and insurance.
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III. RECOMMENDATIONS
It is recommended that appropriate enforcement action be initiated
against the Bunker Hill Company for violation of the existing 113 Notice
of Violation for zinc fuming furnace charging area controls. It is
further recommended that any subsequent judicial or administrative
agreement include the following considerations:
1. A date for rebuilding the zinc oxide baghouse and increasing
the zinc fuming plant stack fan capability.
2. A schedule for the Company to design and install a particulate
control system to control zinc fuming furnace charging emis-
sions and to come into compliance with Idaho Regulation F.
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IV. PROCESS DESCRIPTION
LEAD SMELTER*
The primary function of the Bunker Hill Company lead smelter is to
convert lead concentrate into a high-purity lead product. A simplified
flow diagram for the smelter is shown in Figure 1.
Once at the lead smelter, the concentrates are sampled, blended
with other feed materials and pelletized in a dryer. This pelletized
mixture is conveyed to an updraft sinter machine where it is laid on a
traveling grate, ignited and burned. A large portion of the lead sulfide
(PbS) in the feed is oxidized to lead oxide (PbO) and sulfur dioxide
(SOg). The sinter operation produces a porous sinter material and a
byproduct gas containing the S02> a portion of which is captured and
converted to sulfuric acid in a single-contact, single-adsorption acid
plant. Remaining S02, which is emitted from the tail end of the sinter
machine, is exhausted directly to the main stack. Fines from the sinter
process are recycled through the sinter return circuit.
The sinter is mixed with coke and charged to the blast furnace
where it is burned with oxygen-enriched air. As the coke burns, it
furnishes the heat necessary to reduce the sinter to two molten materials:
a lead bullion, and slag. The slag is further processed in a zinc
fuming furnace before being stockpiled. The flue gases from the zinc
fuming furnace contain zinc oxide, a part of which settles out in the
flue system. The remainder is removed in the baghouse.
Information in this section is derived from references 2,3.
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Figure 1. Simplified process flow sheet for the Bunker Hill Lead Smelter
CO
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The lead bullion from the blast furnace is next purified through a
series of refining steps which include dressing in kettles, softening in
a furnace, and degolding, desilvering and dezincing in various other
kettles. Copper, antimony, arsenic, silver and gold are removed during
these steps and treated further to provide marketable forms. With the
proper amounts of impurities removed, the lead is cast into a final
product.
ZINC FUMING PLANT
System Description*
The purpose of the zinc fuming plant is to recover zinc and lead
oxide from the slag generated in the lead smelter blast furnace operation.
The major components of the plant are the zinc fuming furnace, the raw
material charging systems, the slag granulating pit and scrubber, the
waste heat recovery and gas cooling systems, and the fume collection
system. A flow diagram for the plant is shown in Figure 2.
The Bunker Hill zinc fuming plant began operating in 1943. It was
modified in 1956 to increase the furnace capacity and again in 1975 to
install a granulating scrubber. Presently, the plant can process about
550 to 590 m. tons (600 to 650 tons)/day of blast furnace slag, producing
around 70 m. tons (75 tons)/day of zinc oxide fume. The zinc fuming
plant is operated approximately 80% to 85% of the time the blast furnace
is on-line.
Furnace
In practice, the zinc fuming furnace is a batch operation consisting
* Information in this section is derived from references 4j 5, 63 ?t 8.
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10
AIR
TURBO
BLOWERS
COAL
AIR
*
SLAG FUMING PLANT
B F SLAG
COAL
PULVERIZER
TERTIARY
AIR
FAN
GAS OR OIL
STACK
FAN
SLAG FUMING
FURNACE
WATER WALL
BOILER
SECTION
COMBUSTION
SECTION
WASTE HEAT
BOILER
SECTION
ECONOMIZER
SECTION
ASH
ZnO FUME
ZnO COOLING
TOWER
ZnO FUME
NORBLO ZnO
BAGHOUSE
I
RR CAR |
SCRUBBER
SLAG
GRANULATION
PIT
SURGE BIN
LEADED ZnO
TO MARKET TO
KILN
ASH f | RR CAR
» ' »
TO OPP
RR CAR
TO
OPP
OR MARKET
Figure 2. Process Flow Diagram for Zinc Fuming Plant,
Bunker Hill Lead Smelter
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11
of charging/heating, fuming, and tapping cycles. In the charging/
heating cycle, 4.5 m. ton (5.0 ton) capacity pots of blast furnace slag
are charged to the furnace through a charge chute, while a pulverized
coal and air mixture is injected through tuyeres beneath the surface of
the molten slag bath. As combustion occurs, any solid slag present in
the bath is melted as the operating temperature of the bath is maintained
at about 1,000 to 1,100°C (1,800 to 2,000°F). After charging is completed,
the furnace goes into a fuming phase, during which time the amount of
air entering the furnace bottom is about 60% to 75% of the theoretical
air required for complete combustion. Under these conditions, carbon
monoxide is formed and reduces to metal the lead and zinc oxides present
in the slag. The metals are vaporized, and tertiary air is then blown
into the upper part of the furnace to reoxidize the metal vapor. The
coal added during the fuming cycle serves two conflicting purposes: 1)
it provides sufficient carbon monoxide during combustion to reduce the
majority (90%) of the zinc oxide to zinc vapor, and 2) it releases
enough heat to support the endothermic reduction reactions and maintain
the temperature of the bath within the proper operating limits. Typical
data for the zinc fuming furnace operation are shown in Table 1.
Physically, the fuming furnace is somewhat similar to a reverberatory
furnace made up of steel water jackets [Figure 3]. The furnace hearth
is 4.5 m. long x 2.4 m. wide x 6.8 m. high (1j x 8 x 22 ft). The entire
furnace is water-jacketed with water space tapering from 32 cm (12.5 in)
at the bottom to 13 cm (5 in) at top. The charging door is 2.5 m (8 ft)
in diameter, pneumatically operated, and also is water cooled. The door
is 4 m (13 ft) above the bottom of the furnace. The slag from the
furnace is tapped through two water-cooled tapholes near the bottom of
the furnace. Circulation of cooling water through the water jackets is
accomplished by a thermo syphon action.
The Company does not attempt to control either furnace draft or
furnace temperature directly. These variables are said to be kept
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1?.
Table 1
TYPICAL OPERATING DATA FOP THE ZINC FUMING FURNACE
BUNKER HILL LEAD SMELTER7>B
Average cycle times (minutes)
Charging/heating 20
Fuming 90
Tapping 10
Charges/day 12
Material flowrates (m.tons/hr) (tons/hr)
Blast furnace slag 550-590 600-650
Coal 100 110
Fume collected 70 75
Zinc/lead recovery (% by weight)
Average lead in input slag 1.9
Average lead in output slag 0
Average zinc in input slag 14
Average zinc in output slag 1.4
Fuming furnace design pressure -0.68 cm (-0.25 in) W
t WG = Water Gauge.
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Figure 3. Physical Arrangement of Zinc Fuming Furnace and Waste Heat Boiler (1957)
Bunker Hill Lead Smelter
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14
within proper ranges by the controls used to maintain waste heat boiler
operation. At present, indicators for furnace draft and temperature are
inoperable. Company personnel indicated that this is due to problems
caused by high temperature operation and slag formation on instrument
sensors.
Charging
Operation of the zinc fuming furnace requires the input of air,
pulverized coal and blast furnace slag. Combustion air and pulverized
coal are injected into the slag bath through 28 tuyeres, 14 on each side
of the furnace about 14 cm (5-1/2 in) above the furnace bottom. Primary
and secondary air is provided by two Ingersoll-Rand* four-stage blowers
with a rated capacity of 195 m3/min (6,900 cfm) at 0.6 kg/cm2 (8 psig)
pressure. The blowers are driven by Terry* steam turbines. The tertiary
air required for reducing lead and zinc vapors is provided through two
headers at the top of the zinc fuming furnace. Identical Buffalo Forge*
fans, 58 m3/min (2,040 cfm) at 6.4 cm Water Gauge (WG) (2-1/2 in WG)
supply the air requirements, for each of the headers.
The amount of coal added is chiefly determined by the blast furnace
slag characteristics and the amount of steam to be generated in the
waste heat boiler. The approximate coal requirement is roughly set by
adjusting the Bailey* Type V6 volumetric coal meters, located at the
inlet to the pulverizer feeders. This control is typically not adjusted
to any extent from day-to-day operations. Final control of coal addition
is accomplished by regulating the damper controlling the primary air
flow into the furnace. During the charging/heating and fuming cycles
* Brand name
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15
the coal addition is preset at a fairly constant rate, depending on the
number of pots and the zinc content of the blast furnace slag. The coal
feed rate for a given cycle is usually increased during lancing operations
and decreased during tapping. Coal usage rates are estimated from the
Bailey volumetric meters by using an assumed coal density.
The total flowrate of primary and secondary air is provided at a
relatively constant rate. When primary air is reduced, more air will be
shunted through the secondary headers. The flowrate through the latter
is not controlled. As a result of this and the fact that the tertiary
flowrate is also held fairly constant, the air flowrate to the furnace
does not vary appreciably throughout the furnace cycle. Primary air
flow, primary air pressure and secondary air flowrates are indicated by
instrumentation in the control room.
The molten slag charged to the zinc fuming furnace is tapped from
the lead blast furnace into 4.5 m. ton (5 ton) capacity pots. The pots
are lifted by an 18 m. ton (20 ton) capacity crane from the blast
furnace area to an area adjacent to the zinc fuming furnace. The pots
are stockpiled until the charging cycle commences. Then, each pot is
separately hoisted by a 9 m. ton (10 ton) crane to the charging area
platform located next to the furnace charge spout. An operator manually
breaks up any slag skull which had formed on top of the pot as the slag
has cooled. The charge door is opened and the pot is tipped into a
charge chute. At the end of the period in which each pot is being
emptied, two high-pressure air/water nozzles are activated to help
remove slag from the sloping charge chute walls. Operators also manually
clear material that hangs up in the chute. The charge door is closed
and the emptied pot is lowered to ground level.
The slag skull or shell remaining in the charging pot after normal
charging described above is handled in one of two ways: 1) it is
returned to the blast furnace for melting, or 2) it is emptied with the
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16
other pot contents into the zinc fuming furnace. The latter procedure
requires that enough heat be available to melt the skull as well as
permit the waste heat boiler to operate at proper steam production
rates. If the remaining slag skull is emptied into the furnace, it is
necessary to bump the pot repeatedly against a bumper located just above
the charge door in order to break the slag skull loose.
A typical charge consists of 6 to 9 pots. The operator records the
total amount of blast furnace slag emptied into the zinc fuming furnace
in the operator's log.
Slag Granulation
At the conclusion of the zinc furnace fuming cycle, the spent slag
is tapped during a 10-minute period in which the hot slag is allowed to
flow out of the furnace through the tapping chute and is granulated by
water jets. Approximately 450,000 1 (119,000 gal)/day of smelter
recycle and main reservoir water are used to granulate, cool and transfer
the slag from the granulating pit. The slurry collected in the enclosed
granulating pit is pumped to the slag pile.
The particulates which are generated during slag granulation are
captured within the enclosed space above the granulating pit. They are
ventilated from the granulation pit through a Krebs Elbaire* scrubber
and discharged from a wet fan into a stub stack. The design specifications
for the Krebs scrubber are presented in Table 2.
The Company monitors the granulation operation from instrumentation
provided to indicate the granulating pit water level and granulating
water flowrate. The operation of the scrubber is not monitored by
instrumentation.
Brand name
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17
Table 2
DESIGN PARAMETERS AND SPECIFICATIONS FOR SLAG GRANULATING PIT SCRUBBER
BUNKER HILL LEAD SMELTER
Volume, inlet
Temperature
Pressure, inlet
Density
GAS
o
670 act. m /min (24,000 acfm)
88°C(191°F)saturated
-2.5 cm WG (-1 in WG)
0.7 kg/m3 (0.43 lb/ft3)
Inlet loading
Specific gravity
Particulate size
PARTICULATE
1.6 g/m3 (0.7 gr/acf)
Not available
Not available
Manufacturer
Model
Date Installed
Water Rate
Pressure Drop
SCRUBBER
Krebs Elbaire
PxH 8.6.2
1975
910 1 min (240 gal)/min
7.5 cm WG (3 in WG)
Fractional efficiency 97.1% by weight
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18
Gas Cooling
The fume-laden gas discharged from the zinc fuming furnace is at a
temperature of approximately 1,100°C (2,000°F). To recover heat from
this gas and to cool the gas to within a proper temperature range for
acceptable baghouse operation, the gas is drawn through a cooling
system. This system consists of a waste heat boiler, and a zinc oxide
cooling tower. The waste heat boiler contains a water wall section, a
combustion section, the waste heat boiler proper, and an economizer.
The gas from the zinc fuming furnace first passes into the waste
heat boiler. It is designed to generate about 26,000 to 30,000 kg
(58,000 to 66,000 lb)/hr of steam at 17 atm (250 psig) pressure during
normal operating conditions. The waste heat boiler proper and the
economizer consist of a series of tubes. Water is fed to the economizer
tubes from two lower drums. It rises through the economizer tubes to an
upper drum which feeds the waste heat boiler section. This water then
is circulated through the lower boiler drums, and the boiler tube into
the upper steam boiler drum. The combustion chamber has two oil- or
gas-fired burners which are used when the available steam production
from the zinc fuming furnace offgas falls below 23,000 kg (50,000 lb)/hr
of steam. In addition, a separate auxiliary steam boiler is used if
both the furnace offgas and combustion system are unable to maintain
minimum steam requirements. Instrumentation is provided to record steam
flow, steam pressure, waste gas temperature, waste gas pressure and
various other operating status indicators.
The gases leaving the economizer section of the waste heat boiler
pass through a long balloon flue before entering a zinc oxide cooling
tower. The cooling tower consists of a steel box, 7.6 m. wide by 20 m.
long by 5.6 m. deep (25 x 66 x 18 ft) divided into six compartments by
cross baffles. Between each compartment, there are four large U-shaped
cooling pipes, 1 m. diameter, extending from the top of one compartment
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19
to the top of the next compartment. The inlets of the pipes are fitted
with butterfly dampers to adjust or shut off the gas flow. There are no
automatic controls for the cooling tower operation. Operator judgment
dictates when to bypass one or more of the cooling pipe sections. If
tower exit temperatures appear to be excessive, the operator simply raps
the cooling pipes with a sledge hammer to remove particulate deposits.
The gas leaves the cooling towers through a second balloon flue and
into the zinc oxide baghouse.
Fume Collection
The zinc oxide and lead oxide fumes are collected from the furnace
offgas in the economizer hoppers, ductwork, zinc oxide cooling tower,
and the zinc oxide baghouse. The collected material (fume) in the
baghouse is usually transferred directly from the baghouse hoppers to
railroad cars or to the zinc smelter. The material collected from the
other sources is conveyed by screw conveyor to railroad cars or to a
surge bin from which the dust may be further processed in a gas-fired
kiln.
The zinc oxide baghouse consists of five Northern Blower Company
(NorBlo*) dust arresters, each with a dust-settling chamber and a bag
compartment. Ambient air is introduced to the flue gas just prior to
the baghouse through preset louvers located near the inlet to the first
dust arrester. Each bag compartment contains ten sections with 78 bags
per section. Each Dacron* bag is 15 cm diameter by 2.5 m. long (6 in x
2.7 yd). Each section is automatically isolated from the baghouse
* Brand name
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20
outlet flue and provided with reverse air when the compressed air shaker
for that section is activated. The ten bag sections may be shaken on a
cycle of 4-1/2, 11 or 24 minutes with the length of shake per section
being adjustable.
The design parameters and specifications for the zinc oxide baghouse
are shown in Table 3.
Gas from the baghouse is discharged through an American Blower*
stack fan into the main zinc fuming plant stack. The fan is driven by a
steam turbine which is controlled to maintain the draft in the zinc
fuming plant waste heat boiler within the proper range. The fan was
originally designed to provide 3,540 act. m /min (125,000 acfm) at 100°C
(212°F) and 25 cm (10 in) WG static pressure drop.8
Maintenance and Operation
Ten men per shift are assigned to the zinc fuming plant during
normal operation. One man monitors and operates the fuming furnace and
waste heat boilers. Two men are responsible for charging, tapping, and
cleaning tuyeres. One man operates the steam soot blowers and air
lances for cleaning the boiler tubes. The remaining personnel are
responsible for the kiln, baghouse, overhead crane and granulator
operations.
Maintenance requirements include fairly routine practices for this
type of operation such as removing and cleaning dust deposits, keeping
the charge chute free of debris, and replacing worn or damaged equipment.
Of special significance to this study, however, are those practices
* Brand name
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21
Table 3
DESIGN AND ACTUAL PARAMETERS FOR THE ZINC OXIDE BAGHOUSE
BUNKER HILL LEAD SMELTER3,5
BAGHOUSE
Manufacturer - Northern Blower
Model - 78 DA
Date of Installation - 1943
Bag Area - 5,600 m2 (60,500 ft2)
Air to Cloth Ratio (actual) - 3:1
Pressure Drop (actual) - 10-15 cm (4-6 in) WG
Pressure Drop (design) - 3 cm (1 in) WG
Fractional Efficiency - Unknown
GAS
•3
Flowrate (actual) - 5,100 act. m /min (180,000 acfm)
Temperature (actual - 66°C (150°F)
Moisture (actual) - 1-4 vol%
PARTICULATE
Inlet particulate concentration - Unknown
Inlet particulate size - 0.7p (mass median diameter)
-------
22
which affect the uncontrolled emission of participates. These would
include maintenance of water jackets, boiler tubes, lance doors, the
charging door, and the baghouse.
The furnace water jackets form the walls, top and bottom of the
zinc fuming furnace and water wall boiler. These jackets are fastened
together and, as a result, gaps can form as expansion, contraction and
vibration occur within the furnace. The Company has stated that leaks
in the zinc fuming furnace are caulked on an "as needed" basis.7 There
is no inspection conducted to routinely locate furnace leaks.
The tubes in the waste heat boiler are regularly lanced during each
8-hour shift to remove particulate deposits. Particulate deposits
reduce steam production but more importantly, from a fugitive emission
standpoint, they reduce the negative draft available in the fuming
furnace.
The lance doors for the waste heat boiler sections provide an
access for lancing the boiler tubes. These doors are designed to seat
under negative draft and will leak under positive pressures. In addition,
these doors are exposed to varying temperature and mechanical shocks,
created as the doors are opened and shut and as the air lance is inserted
and withdrawn. As a result, the doors may not seat properly, thereby
allowing particulate emissions to escape under pressure through gaps.
The Company stated that no maintenance or inspection of the doors is
performed other than to make sure the doors are closed when not in use.
During the EPA inspections conducted in August 1976 and February 1977,
it was noted that the lance doors were leaking at several locations.
The charge door is pneumatically operated and is purposely opened
only when the slag pots are being emptied into the furnace. Particulate
emissions during fuming and tapping do result when the door does not
close properly, either due to a malfunction by the pneumatic operator or
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23
a buildup of solid material. The Company has stated that these problems
are minimal and are corrected when they occur.7
The zinc oxide baghouse affects fugitive emissions by limiting the
negative draft available in the fuming furnace and waste heat boiler.
This is caused by particulate buildup on the bags, and causes the
pressure drop across the baghouse to increase. If the shake cycle on
the bags is increased, the baghouse pressure can be lowered and the
available draft is then increased. During the February 1977 EPA inspection,
it was observed that the baghouse shake cycle was highly variable. The
Company indicated that this was due to badly worn pneumatic shake valves,
but stated that these valves, as well as the rest of baghouse equipment,
were being rebuilt.
Particulate Sources
Particulate emissions result from four major sources within the
zinc fuming plant. These include the zinc fuming plant stack, the
granulating scrubber stack, the zinc fuming furnace charging area
stack, and the zinc fuming furnace building louver wall openings.
Main Stack
The main stack receives the major gaseous and particulate emissions
from the zinc fuming furnace. The quantity of these emissions is
expected to vary with state-of-heat of the furnace, reaching a maximum
during the charging/heating cycle and the early stages of the fuming
cycle and a minimum during the tapping cycle. Particulate sizes and
concentrations can also expect to vary somewhat during the batch operation.
Data from stack sampling tests conducted by Valentine, Fisher and Tomlinson2
indicate particulate concentration of 0.05 g/std. m3 (0.02 gr/scf) with
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24
o
an average gas flow of 5,100 m /min (180,000 acfm) at the stack.2
Total participate emissions are estimated to be about 11 kg (24 lb)/hr.
Granulating Scrubber Stack
The granulating scrubber and stack are operated intermittently,
about every 10 to 20 minutes during the zinc fuming furnace slag tapping
cycle. The emissions consist of fugitive emissions from the tapping
launder, granulator particulate which are not caught in the scrubber,
and solids from the mist which is carried over from the scrubber spray.
Tests conducted by Alsid, Snowden and Associates9 indicate approximately
0.6 kg (1.3 lb)/hr particulate is emitted.
CharginQ Area Hood
The charging area hood is located just above the fuming furnace
charge chute. The hood is provided with a vent fan and a stack through
which the fumes exit to the atmosphere. The largest portion of parti-
culate emitted through the charging area stack is generated during the
charging cycle. During the charging/heating cycle, fugitive emissions
are released from the zinc fuming furnace from the slag pots and from
the molten slag as it is emptied into the furnace. The proportionate
amounts generated by each contributor are difficult to estimate. The
charging area stack also exhausts fumes from door and furnace leaks
throughout all furnace cycles. The fumes in the charging area hood
emissions are expected to have an 0.7p mass median particle diameter.
Emissions from the charge area hood were measured by Valentine, Fisher
and Tomlinson.2 The emissions were found to be about 0.07 g/std. m
(0.03 gr/scf) at an average flowrate of 1,330 act. m3/min (46,800 acfm).
This amounts to 5.4 kg (12 lb)/hr.
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25
Building Louvers
Fumes which are emitted from leaks and the charging operation are
not always collected in the charging hood and, instead, are emitted
through the zinc fuming furnace building louvered wall openings. These
louvers are located on the roof of the zinc refinery and have a total
22
area of 46 m (500 ft ). Observations of the furnace operation indicated
that fumes typically are emitted through the building louvers approximately
10 minutes every half-hour.10 Fugitive emission measurements based on
particulate collected with a high-volume sampler were conducted by PEDCO,
Inc.10 These measurements indicated that the building louvers were
emitting about 9.6 kg (21 lb)/hr of suspended particulate at a flowrate
of approximately 4,960 act. m3/min (175,000 acfm).
Emission Rate
The total mass rates of all solid materials charged and particulate
emitted from the zinc fuming plant are summarized in Table 4. Based on
data presented in the table, the plant emits approximately 27 kg (58
lb)/hr of particulate at a charging rate of 27 to 29 m. tons (30 to 32
tons)/hr.
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26
Table 4
ESTIMATED MASS PATES FOR THE ZINC FUMING PLANT
BUNKER HILL LEAD SMELTER
MATERIAL CHARGED SKETCH PARTICIPATE SOURCES
Coal
7
Blast furnace
Slag .
1 ' /
ZINC
FUMING
PLANT
Main stack v
r
Granulating stack ^
/
Charging area hood v
/
Building louvers \
/
Material
Mass Rate
Materials charged
Coal
Blast furnace slag
TOTAL
Particulate emitted
Main stack
Granulating stack
Charging area hood
Building louvers
TOTAL
m. tons/day
100
550-590
650-690
kg/hr
11
0.5
5.5
9.5
27
tons/day
110
600-650
710-760
Ib/hr
24
1
12
21
58
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V. APPLICABLE REGULATIONS
There are two Idaho State air regulations which can be applied to
the operation of the zinc fuming furnace: Idaho Regulation F for
control of fugitive dust, and Idaho Regulation H for control of particu-
late emissions from industrial processes. The complete text of these
regulations can be found in Appendix B. The discussion that follows
reviews the Company's compliance with Regulations F and H based upon the
observations made in this study.
REGULATION F - CONTROL OF FUGITIVE DUST
Idaho Regulation F requires that "All reasonable precautions ...
be taken to prevent particulate matter from becoming airborne." The
regulation further states that reasonable precautions may include, but
are not limited to, "... Installation and use of hoods, fansj and fabric
filters or equivalent systems to enclose and vent the handling of dusty
materials." In addition to these guidelines, it was noted during this
study that the zinc fuming plants in East Helena, Montana, and El Paso,
Texas [Section VIII of this report] have or plan to install charging
emission collection and control systems. The Bunker Hill Company has
made no effort to enclose or control fugitive charging emissions from
the zinc fuming plant operation.
As a result of the regulation requirements and practices at other
zinc fuming plant installations, it is reasonable and prudent to assume
that, to comply with Idaho Regulation F, the Company must implement
fugitive emission controls. There are various approaches which can be
used to control fugitive emissions, and some of these are discussed in
Section VI, of this report. As a minimum, however, some means to
control charging emissions will be necessary.
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28
REGULATION H - CONTROL OF PARTICULATE EMISSIONS FROM INDUSTRIAL PROCESSES
Idaho Regulation H limits the rate of particulate emitted from any
process to the values shown in Table 5. In this case, the zinc fuming
plant is considered a process. Coal and blast furnace slag are the
solid materials which make up the process weight input. The particulate
sources for which measurements have been made include the zinc fuming
plant stack, the granulator stack, the charging area stack and the
building louver openings. Based on a process weight input of 29 m. tons
(32 tons)/hr [Table 4], the allowable emission rate is 18 kg (40 lb)/hr.
Actual emissions are estimated to be 27 kg (58 lb)/hr [Table 4]. However,
EPA Method 5 (40 CFR 60, Vol 36, No. 247, Dec. 23, 1971) measurements were
only made for emissions from the three stacks. These emissions were 17
kg (37 lb)/hr. If only the emissions determined by Method 5 are con-
sidered, then the zinc fuming plant does not violate Regulation H.
* E = 55.0(30)0>11-40, E = 40
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29
Table 5
ALLOWABLE RATE OF EMISSION BASED ON
PROCESS WEIGHT RATE*
Idaho - Regulation H
Process Weight
Rate
Ib/hr
100
200
400
600
800
1,000
1,500
2,000
2,500
3,000
3,500
4,000
5,000
6,000
7,000
8,000
9,000
10,000
12,000
tons/hr
0.05
0.10
0.20
0.30
0.40
0.50
0.75
1.00
1.25
1.50
1.75
2.00
2.50
3.00
3.50
4.00
4.50
5.00
6.00
Rate of
Emission
Ib/hr
0.551
0.877
1.40
1.83
2.22
2.58
3.38
4.10
4.76
5.38
5.96
6.52
7.58
8.56
9.49
10.4
11.2
12.0
13.6
Process Weight
Rate
Ib/hr
16,000
18,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
100,000
120,000
140,000
160,000
200,000
1,000,000
2,000,000 1
6,000,000 3
tons/hr
8.00
9.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
45.00
50.00
60.00
70.00
80.00
100.00
500.00
,000.00
,000.00
Rate of
Emission
Ib/hr
16.5
17.9
19.2
25.2
30.5
35.4
40.0
41.3
42.5
43.6
44.6
46.3
47.8
49.0
51.2
69.0
77.6
92.7
Interpolation of the data in this table for process weight rates up to 60,000
Ib/hr shall be accomplished by use of the equation E - 4.10 p°-67^ <#& inter-
polation and extrapolation of the data for process weight rates in excess of
60,000 Ib/hr shall be accomplished by use of the equation:
E = 55.0 JT' - 401 where E = rate of emission in Ib/hr
and P = process weight rate in tons/hr.
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VI. PARTICULATE COLLECTION AND CONTROL
The purpose of this section is to review the alternatives for con-
trolling fugitive emissions from the zinc fuming plant. As discussed in
Section V, it is apparent that the Bunker Hill Company is not complying
with Idaho Air Regulation F requiring that "reasonable precautions... be
taken to prevent partiaulate from becoming airborne. " This section
reviews some of the potential methods the Company could implement to
comply with the regulation.
OPERATION AND MAINTENANCE
Operation and maintenance modifications, as discussed here, include
procedural changes which could be implemented without changing existing
equipment. Occasionally, by altering maintenance and operating practices
it is possible to significantly reduce fugitive emissions.
Maintenance modifications reviewed in this study were those which
would directly reduce fugitive emissions. Specifically, the area which
could be improved most and for which the Company has been cited by the
£ J
EPA in a 113 Notice of Violation is the maintenance of waste heat
boiler doors. These doors should be more frequently inspected by the
Company with the sole purpose of noting significant fugitive emissions,
and the latch mechanism tightened as necessary. Also, as part of the
routine inspection, the physical condition of the zinc fuming furnace
Clean Air Aot3 as Amended 42 USC 1857 (c).
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31
should be examined. These practices could be achieved with a minimum
increase in manpower requirements. It should be noted, however, that
the waste heat boiler doors are designed to operate at negative pres-
sures. If the boilers are under positive pressure, no amount of main-
tenance will prevent door leakage.
The zinc fuming furnace and the waste heat boiler are designed to
operate under negative pressure. During the EPA-conducted inspections,
however, several leaking doors and various emissions from the furnace
were observed signifying that the fuming furnace and portions of the
boiler are under positive pressure. Consequently, operating modifica-
tions that would increase the available draft should be considered.
These could include operating the baghouse shaker on a more frequent
cleaning cycle and increasing the frequency and thoroughness of air
lancing the boiler tubes.
More frequently and/or prolonged baghouse cleaning would lower the
pressure drop across the bags and, therefore, lower the pressure at
the zinc fuming furnace. The drawbacks to this approach are increased
bag wear and the possibility of "puffs" of particulate occurring as
cleaned bags are brought on line. As a result, the bag cleaning cycle
should be optimized for maximum particulate control. At present, the
disrepair and poor condition of the existing baghouse may further limit
the effectiveness of this approach.
The Company currently has a program to routinely air lance the
boiler tubes. It is possible, however, to increase the frequency of
this practice by limiting some of the collateral assignments of the
lancer operator. This approach, as in the case of changing the baghouse
cleaning cycle, must be optimized with other operational requirements.
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32
Although the above described operating and maintenance modifications
can reduce fugitive emissions, they alone are not likely to enable the
plant to comply with Idaho Air Regulation F.
PROCESS MODIFICATIONS
In that process modifications are considered to include equipment
changes, they are differentiated here from maintenance and operating
modifications. For the zinc fuming operation, the most feasible process
modification involves increasing the draft at the furnace. This would
reduce fumes presently escaping from the furnace and the waste heat
boiler and which subsequently become uncontrolled fugitive emissions.
The furnace draft can be increased by increasing the static pressure
drop provided by the stack fan and/or by reducing the pressure drop in
the system, most likely at the baghouse.
The Company has indicated that it is currently rebuilding the
existing steam driver for the stack fan so that it will operate con-
tinuously at 640 rpm.7 The original fan was designed to operate at 509
rpm. The fan can then generate 5,130 act. m /min (181,000 acfm) at 25
cm (10 in) WG whereas the original fan was designed for 3,540 act.
m3/min (125,000 acfm) at 25 cm (10 in) WG. The characteristic fan
curves are shown in Figure 4. The Company has stated that the stack fan
with rebuilt driver will be operating with the largest diameter impeller
and at the highest speeds suitable for this model.7 Therefore, to
further increase available static pressure, an additional fan would have
to be installed in series with the existing stack fan. Because of
inadequate space near the existing stack fan, a new fan could be located
between the zinc oxide cooling tower and the zinc oxide baghouse. It
should be designed so that both fans could be operated to provide an
additional 3 to 5 cm (1 to 2 in) WG of static pressure.
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33
10.0.
5.0-
625 RPM
20
Figure 4.
40 60
% CFM (in thousands)
80
100
Temperature = 212°F
Elevation = 2,300 ft
Fan Characteristic Curves for Zinc Fuming Plant
Stack Fan, Bunker Hill Lead Smelter
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34
The Company also indicated that it is replacing the existing zinc
oxide baghouse with a similar system having the same basic capacity and
components.7 This is not expected to reduce the baghouse pressure drop
below the current7 4 inch WG range. To reduce the pressure drop, an
additional baghouse section could be installed. If a section similar to
those now present were erected, it is estimated that the pressure drop
would be reduced by 1 t.o 3 cm (0.5 to 1 in) WG.
CHARGING EMISSIONS COLLECTION
Maintenance, operational, and process modifications can reduce the
amount of fugitive particulate emissions from the zinc fuming plant;
however, it is unlikely that these changes will provide the extent of
control necessary to meet Idaho Air Regulation F. At other zinc fuming
plant installations in the United States [Section VIII] it has been
necessary to develop means for collecting and removing the emissions
generated during the charging cycle. In this subsection alternatives
for collecting charging emissions are discussed, while in the next
subsection particulate removal alternatives for the charging emissions
are reviewed.
A very critical part of reducing particulate emissions to accepted
levels is to have a properly operating fume collection system. The
existing collection system consists of a 2.4 m x 3.7 m (8 x 12 ft) hood
located above the furnace charge door [Figure 5].8 The hood is con-
nected to a vent fan and stub stack through which emissions are dis-
charged. The hood does not adequately collect charging emissions for a
number of reasons. Basically, the hood is too small and too distant
from the charge area for the available vent fan capacity and for the
magnitude of charging emissions. As a result, fumes escape around the
hood and out through the louvered building openings. It is estimated,
See Appendix C for calculation.
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35
0.* _ ff.y » „• f XV ^«' < ft *W* *•-!
Figure 5. Elevation Drawing Showing Location of Existing
Charge Area Hood for the Zinc Fuming Plant
Bunker Hill Lead Smelter
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36
based on fugitive emission testing, that more fume escapes through the
building openings than is collected by the present charging area hood.
To improve fume collection many alternatives are available. Four
alternatives with subsequent ventilation and hooding requirements are
outlined in Table 6. Restrictions and guidelines used in establishing
these alternatives are as follows:
o The hooding system must allow for the crane access so that blast
furnace pots can be properly emptied into the charging hopper.
o The hooding system must take into account the open nature of the
building and the resulting problems with cross drafts disturbing
ventilating air flow. When possible, curtains should be used to
restrict air flow interferences.
o A canopy-type hood is considered more suited to the control of hot
processes where sudden surges of hot gases and vapors occur.
o An "appropriate" fume collection system should be capable of re-
moving 70% to 90% of the fugitive emissions from the zinc fuming
charging operation.
The most desirable alternative is considered the one requiring less
air volume and, hence, a smaller particulate collection system and fan.
As a result, the dual canopy hood system designed as Alternative A [See
Section VII] was selected for the system despite some drawbacks due to
restricting crane operation. With this alternative, the crane operator
would have to be careful in bumping and moving the slag pots while these
were beneath the collection hoods. A schematic of Alternative A is
shown in Figure 6. The emissions to the particulate removal system
would have the following estimated characteristics:
Flow 2,270 act. m3/min (80,000 acfm)
Temperature 50 to 70°C (120 to 160°F)
Moisture, Volume 1% to 3%
Particle Inlet loading 14 to 28 kg/hr (30 to 60 Ib/hr)
Particle Size 0.7 M MMD
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37
Table 6
ALTERNATIVES FOR PROVIDING APPROPRIATE VENTILATION OF THE ZIHC FUMING FURNACE CHARGING AREA
BUNKER HILL LEAD SMELTER
Alternative
Arrangement
Locations
Estimated Ventilation
Air Requirements
Comments
A
Modified canopy
each approximately
2.4 x 2.1 m
(8x7 ft)
m /min
Side-by-side 2,200
hood located
above charge
hopper 0.6 m
(2 ft) space
between hoods
to allow over-
head crane access.
cfm
80,000 Some restriction and
obstruction to view of
crane operator. Side
enclosed to minimize
drafts.
Dual side draft
hoods, each
2.4 x 2.7 m
(8x9 ft)
Single canopy
hood 6.4 x 5.5 m
(21 x 18 ft)
Building ceiling
collection
On each side of
charge hopper,
hoods facing one
another.
Hood located
approximately
4.9 m (16 ft)
above charge
hopper at elevation
of existing hood.
Top of zinc fuming
building
3,900 140,000
7,600
270,000
11,800 420,000
Release of fume into
zone of very rapid air
motion expected to
require relatively high
capture velocities.
Subject to high cross
draft interference.
Large inlet velocity
and ventilating rate
will be required.
This approach is
practical only if the
entire top of zinc
funning building can
be closed to form a
hood. Large venti-
lation rates will be
required.
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38
FURNACE WALL
PLAN
HOODS
•CRANE RAIL AXIS
APPROXIMATE
SCALE
1" = 4'
ELEVATION
Figure 6. Sketch of Hooding Arrangement for Zinc Fuming Furnace
Charge Area (Alternative A), Bunker Hill Lead Smelter
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39
CHARGING EMISSIONS CONTROL
Once the charging emissions from the zinc fuming furnace are
adequately collected, the fumes must be removed in an appropriate par-
ticulate removal device. Table 7 shows the alternatives that were
evaluated for treating the charging emissions. It was found that the
existing granulating scrubber, the existing zinc oxide baghouse, the
existing main lead smelter baghouse, a new wet scrubber, and a new
electrostatic precipitator (ESP) were not acceptable approaches for
technical reasons. The best devices for controlling the charging
emission appear to be a new baghouse designed specifically for the
charging emissions, an expanded zinc oxide baghouse, or an expanded
main baghouse. The gas collection systems discussed previously
(including hoods, ducting, and a vent fan) will be required for each
of these alternatives.
New Baghouse
A new baghouse designed for the charging emissions could be ex-
pected to have acrylic bags, arranged in a multichamber unit with
2 ?
3,700 m (40,000 ft ) of bag area. The unit could use a shaker cleaning
system and could be designed for 99+% efficiency. It could be located
nearby (e.g., on the roof) provided that any support structure could be
upgraded as necessary. Auxiliary requirements would include a fan,
ducting, isolation gates, instrumentation and a solids removal system.
Expanded Zinc Oxide Baqhouse
The existing zinc oxide baghouse system could be modified by the
addition of a second stack fan and an additional baghouse section. The
ventilation air from the furnace charging area could be introduced at
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40
Table 7
ALTEHUATIYES FOR COLLECTING AlID COHTROLLUIG PARTICULATE FROM ZIllC FUMING FURNACE CHARGING EMISSIONS
BUNKER HILL LEAD SMELTER
Control Device
Alternative
Estimated Reduction
in Fugitive Emissions
Technical
Acceptability
Technical
Review
Existing granulating
scrubber
Existing zinc oxide
baghouse
10-501
30-702
Existing main baghouse
New baghouse 70-90%
New scrubber
60-902
New ESP
60-902
Modified zinc oxide
baghouse
Modified main baghouse
80-902
80-902
Not acceptable The present scrubber is not large
enough for the gas volume to be
treated and, further, is an inertia]
impaction device which is not
efficient for sub-micron participate.
Not acceptable The existing zinc oxide baghouse is
undersized for the current con-
ditions (3:1 air-to-cloth ratio,
2:1 desired). Additional flow would
further increase baghouse pressure
drop and increase furnace pressure,
thereby increasing leakage.
Not acceptable The existing main baghouse is inade-
quate and is currently being expanded.
Acceptable A baghouse would provide good particu-
late control in this application.
Baghouses are used throughout the
smelter and the Company snould be
well-acquainted with their operation.
Not acceptable The low grain loading and small
particle size would require a high-
energy venturi (^100 cm WG AP) for
this application. This fact and the
need to handle a blowdown slurry are
large drawbacks to the use of a
scrubber.
Not acceptable Technically, an electrostatic pre-
cipitator could be used in this
application. However, the lack of
experience of ESP's in similar zinc
fuming furnace operations would hinder
proper design and may lead to over-
conservative sizing criteria and
higher costs. Also, the Company has
had limited experience with ESP
operations.
Acceptable The addition of another zinc oxide bag-
house section and additional stack
fan capacity not only provides a means
of treating charging emissions but also
can increase the draft in the furnace
and waste heat boiler. This reduces
fugitive emissions from these sources.
Hay be The main lead smelter baghouse is cur-
acceptable rently being increased in capacity to
handle the lead smelter blast furnace
upsets. Due to the unpredictable nature
of such upsets it is premature to con-
sider or define further modifications
which would allow the baghouse to treat
fuming furnace charginq emissions. This
Should be analyzed after the currently
planned modifications are put into operation.
From preliminary observations it appears
that there is adequate capacity for treat-
ing charging emission for a large fraction
of the time with little additional modifi-
cation to the main baghouse.
-------
the inlet to the expanded zinc oxide baghouse. Since this air would
typically approach ambient conditions there would be reduced need for
cooling air. As a result, the existing cooling air louvers at baghouse
inlet could be partially closed. The actual additional flowrate to the
zinc oxide baghouse would then be much less than the 2,270 act. m/min
(80,000 acfm) nominally provided by the charge area ventilation fan.
This approach has the added advantage of increasing the available draft
in the fuming furnace and waste heat boiler. Therefore, besides re-
ducing charging emissions, other zinc fuming plant fugitive emissions
would be reduced. Auxiliary requirements for implementing this modifi-
cation would include a ventilation fan, ducting, isolation gates,
instrumentation and a solids removal system.
Modified Main Baghouse
The Company is currently in the process of expanding the main bag-
house to accommodate upsets from the lead smelter blast furnaces.7 The
planned baghouse modifications will accommodate a peak flowrate of
Q
17,000 act. m/min (600,000 acfm) and a normal flowrate of 11,300 act.
o
m/min (400,000 acfm). There will be seven baghouse sections providing
o
an air-to-cloth ratio of 0.6 act. m/min per square-meter cloth area
(1.8 acfm per square-foot cloth area) at normal flowrates. The Company
has indicated, however, that the blast furnace upsets are highly unpre-
dictable. The Company also has indicated that the structural require-
ments for the baghouse will be just adequate when the planned expansions
are made. Consequently, it would be imprudent at this time to suggest
further main baghouse modifications. It does appear, however, that
after the planned changes are made, sufficient capacity will be avail-
able in the baghouse to accommodate the zinc fuming furnace charging
emissions. The few additional modifications necessary to allow the
baghouse to treat these emissions should be insignificant from an
engineering and cost standpoint.
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VII. COST ANALYSIS
The alternatives for reducing fugitive emissions at the zinc fuming
furnace include operation, maintenance, process, and particulate collec-
tion and modifications. The operation and maintenance changes pre-
viously identified could be implemented with very little cost. Process,
and collection and control modifications, however, will involve instal-
lation and operation cost investments. Preliminary cost estimates for
these alternatives are shown in Appendix C.
Table 8 shows the installed costs and operating costs required for
five process and/or control equipment modifications based on preliminary
NEIC estimates. The alternatives can be further summarized as follows.
Installed Yearly
Cost Operating
Alternative Cost
($) ($)
A
B
C
D
E
Additional stack fan
Additional zinc oxide
baghouse section
Charging emission
control - new baghouse
Charging emission
control - expanded
zinc oxide baghouse
Charging emission
control - modified main
baghouse [see Note 4,
Table 8]
64,000
195,000
370,000
320,000
57,000
22,000
52,000
75,000
83,000
14,000
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Table 8
smiua OF COSTS FOR ALTERNATIVES TO REDUCE zinc FUMING FURNACE FUGITIVE EMISSIONS
BUNKER HILL LEAD SHELTER
\ A
^^Alternatives Additional
x. Stack Fan
B
Additional
Zinc Oxide
Baghouse Section
C
Charging Emission
Control -
New Baghouse
0
Charging Emission
Control -
Expanded Zinc Oxide
Baghouse
E
Charging Emission
Control-
Modified Main
Baghouse
DESCRIPTION OF ALTERNATIVE
INSTALLED COST (1C)
1.Collectors
2.Auxiliaries
(hood, fans,
ductwork, etc.)
3.Installation
TOTAL
Add an additional stack
fan between the zinc
oxide cooling tower and
the baghouse. The fan
should be nominally
capable of 5,000 act.
m3/min(180,000 acfm)
at 12 cm WG (5 in WG).
$54.000
$10,000
$64.000
tttt
Add an additional
section to the
to the existing zinc
oxide baghouse.
The section would be
identical to one of
of the existing
sections.
$180.000
$25,000
$90,000
$195,000
YEARLY OPERATING COSTS
Direct
1.Operating Labor
Operator (S5/hr)
Supervisor (S8/hr)
Benefits (25X of labor)
2.Maintenance $1.500
(labor, materials and
replacement parts)
3.Electricity $11,500
(0.008c/kwh)
Indirect
1 .Depreciation $6,500
(10% 1C)
2.Taxes and Insurance $2,000
3.Plant Overhead $500
(50% of labor and
maintenance)
TOTAL (nearest thousand $) $22,000
$15.000
$19,500
$6,000
$7,500
$52,000
Install charging
area collection
hoods, ductwork, a
ventilation fan,
a separate baghouse
and necessary
auxiliary
equipment.
$200,000
$50,000
$120,000
$370.000
$2.000
$500
$500
$12.500
$3.500
$37,000
$11,000
$7.500
$75.000
Install charging area
collection hoods, a
new ventilation fan,
and necessary duct-
work to route the
emissions to the
inlet of the exist-
ing zinc oxide bag-
house section similar
to those described in
alternatives A and B.
$80,000
$120.000
$120,000
$320.000
Install charging area
hoods, a ventilation
fan, and necessary
ductwork to route the
emissions to the inlet
of the modified main
lead smelter baghouse.
ttt
$37.000
$22.000
$57.000
$17.000
$16.000
$32,000
$9,500
$8,000
$83,000
S500
$4,500
$6,000
$2.000
$500
$14,000
For support calculations, see Appendix C.
All coeia are 1-30% prelvnnary estimates. „....,» i i „
Tr.e coate for Alternative E assure that the modified main baghouee can be uaed for sine fuming plant charging
emissions uith only ninor rradificationa. . . ,
tttt All operating costs assume a 701 annual operating factor uith the exception of the nea baghouse emission control
eye tern imihich a 33% operating factor ia used.
t
tt
ttt
CO
-------
44
In reviewing these estimates it is important to note that the
actual reductions in charging emissions if alternatives A or B are
selected are unknown. It is expected that these alternatives, in them-
selves, will not allow the fuming furnace operation to achieve compliance
with Idaho particulate regulations. However, either of the alternatives
should result in a significant decrease in charging emissions. By
reducing charging emissions by alternatives A or B, it is possible to
reduce the particulate load and capture velocities required for the
collection and control of the remaining charging emissions. If the
volume and efficiency requirements for controlling the remaining charging
emissions are reduced, then the costs of charging emission controls
(Alternatives C, D, and E) may be substantially decreased from the costs
shown in Table 8.
All cost estimates developed in this study should be considered as
preliminary (+30%) estimates. Installed costs include engineering,
installation and equipment costs but do not include costs associated
with production time lost during installation. Annual operating costs
include direct cost, such as maintenance, replacement parts, etc., as
well as indirect costs incurred in depreciation, taxes and insurance.
-------
VIII. RELATED INDUSTRY EXPERIENCE
Based on a survey made during this study, there are only two other
lead smelters located In the United States which have zinc fuming opera-
tions. These are the ASARCO lead smelters in East Helena, Montana, and
El Paso, Texas. The NEIC conducted inspections of the East Helena
facility on July 22, 1976 and of the El Paso facility on February 3, 1977,
The following subsections present a short review of the process,
emission observations, and fugitive emission controls noted during
inspections at these installations.
ASARCO - MONTANA*
Process Description
The ASARCO lead smelter is about one-quarter mile south of East
Helena, Montana. Built in 1888, it has been modified many times since
then. A custom smelter, it specializes in processing high sulfur-lead
concentrates and zinc residues from locations throughout the world.
A block diagram showing the overall smelter operation is presented
in Figure 7. An updraft sinter machine receives concentrates, residues,
limestone, silica and coke and produces a granular product (sinter)
suitable for charging to a blast furnace where it is reduced with coke
and scrap iron to produce a crude lead bullion. The crude bullion is
processed at a dressing plant to produce a bullion-grade lead ready for
final refining. Silver and gold are removed during refining. Copper
matte, a speiss (Cu, As, Sb), and blast furnace baghouse dust are shipped
as products requiring further processing.
* Information in this section is derived from reference 11.
-------
46
.~,.~r,^j, w- • --. ,
G /SO -iCf" PI PCS -/Z.'
7 ) Auxr
~
&.'Htkj&f-SjJT $ CAP- 30073*1 f>. ZSf/k
- < -
Figure 7. Lead Smelter Plant Flow Sheet
ASARCO, East Helena, Montana
-------
47
The zinc fuming plant was designed by Anaconda and constructed in
1927; ASARCO purchased the plant in 1972. This plant is essentially a
batch operation. The purpose of the zinc fuming plant is to smelt slag
from the blast furnace and mined slag from a storage pile producing zinc
oxide, lead oxide, and copper matte. The slag enters a furnace with a
coal and air mixture where it is heated by combustion of the coal under
reducing conditions. The zinc and lead initially present in the slag
are reduced, vaporized, re-oxidized and carried with the offgas through
a cooling system by an induced draft fan. The offgas passes through a
balloon flue and enters a baghouse where the lead and zinc oxide fumes
are removed. In addition to the main offgas, the baghouse receives
fumes which are vented from the hooded zinc fuming furnace charging and
tapping areas. The exhaust gas from the baghouse is discharged to a
stack. The slag from zinc fuming furnace is tapped into a gas-fired
holding furnace where copper matte and waste slag are separated. The
total cycle time for the process is about 165 minutes. A process flow
diagram of the zinc fuming plant, prepared during the inspection, is
shown in Figure 8.
Table 9 shows the operating design data for zinc fuming plant
operation. The plant processes approximately 12 m. tons/hr of blast
furnace slag and 7.5 m. tons/hr of mine slag, producing approximately
3.0 m. tons/hr of zinc and lead oxide fume. The furnace is a bolted
water-wall furnace with a capacity of approximately 55 m. tons. The
zinc fuming plant handles seven to eight charges per day.
Process and Emissions Observations
The zinc fuming furnace was observed throughout its full cycle of
operation during the July 22, 1976 inspection. Observations were made
as to how each of the process steps was conducted, where fugitive
emissions occurred, how the emissions were collected and/or controlled,
the effectiveness of the collection/control systems, and what factors
appeared to most influence the emissions and their control.
-------
48
AIR—p-
AIR — >•
COAL *"
SOLIDS
ZINC F
i
TERTIARY
AIR BLOWERS
Dl ACT
FURNACE
AIR BLOWERS
FURNACEl
SLAG A
MINED
SLAG
r _u — — I
tl
ZINC FUMING SPENT SLAG | HOI
COAL
PULVERIZERS
AND FEEDERS
RECYCLED TO
UMING FURNACE
| FURNACE
-• - v - ll
1^
JT
WATER-COOLED 1 J^p
j PI iir ] uullr
fM PANFI F
\
FUME U-TU
M GAS CO
I
LUE J
TUE 1
j
VENTILATION
FAN
T
BE !
OLER I
1 FUGITIVE
J CHARGING;
HOODS
r
BAGHOUSE
FAN
•
LOADING
'
OUSE
.DING
JRNACE
COPPER
MATTE
TO
TACOMA
EMISSIONS FROM
'TAPPING AREA
Figure 8. Zinc Fuming Plant Flow Sheet
ASARCO, East Helena, Montana
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49
Table 9
OPERATING AND DESIGN INFORMATION
ASARCO - MONTANA ZINC FUMING PLANT11
OPERATING
Average cycle times (minutes)
Charging/heating 60-75
Fuming 60-90
Tapping 10-15
Charges/day 7-8
Material flowrates (m.tons/hr) (tons/hr)
Blast furnace slag 12.0 13.2
Mine slag 7.5 8.3
Coal 4.3 4.7
Fume collected 3.0 3.3
Zinc/lead recovery (% by weight)
Average lead in input slag 1-4
Average lead in output slag 0
Average zinc in input slag 12
Average zinc in output slag <2
3
Air flowrate, charging 450 act. m /min.
FURNACE
Type water-wall (bolted)
Capacity 55 m.tons 61 tons
Dimensions 6.4 x 2.4 x 5.2 m (21 x 19 x 17 ft)
Tuyeres 20/side on 30 cm centers, 14 cm
from bottom, 4 cm diameter
Charging Hot slag is charged through charge hole on south side
of furnace approximately 2.4 m from top of furnace.
Cold slag is charged by conveyor into a chute at the
top of the furnace on the east side.
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50
The zinc fuming furnace is charged with 4.5 m. ton (5 ton) capacity
pots of blast furnace slag which are emptied by crane into a furnace
charging hole and with mined slag which is discharged from a continuous
conveyor into a second charging hole near the top of the furnace.
Pulverized coal and air are blown through two rows of tuyeres into the
bottom of the furnace. The crane lifts each pot over the charging hole
and swings it back and forth, banging the pot against a bumper located
above the opening. The pots are handled this way to break up skulls, or
hardened material, which are formed as the pots cool. The pots observed
were completely empty after the operation and no "pot shell" was returned
to the blast furnace. It took about 3 to 5 minutes to empty each pot.
Seven to eight pots are emptied into the furnace for a given charge.
Emissions of fumes result from a number of sources during the
charging/heating cycle. The most significant of these sources observed
were the charge hole and the slag pots which emitted fumes as they were
emptied during the charge. Other sources of emissions were the cold
(mined) slag entry chute as the material was charged, and the leaks in
the furnace walls. These leaks were much more significant during charging
than during the subsequent steps of the process cycle. This was probably
due to the fact that a greater furnace pressure occurred during the
charging period.
The fumes from the hot slag charging operation are collected by an
overhanging hood with an air intake over the furnace top. The degree of
fume collection appeared to vary with the individual crane operator's
technique. During the first observed charge, emptying of the pots was
less vigorous, and resultant fume collection approached 90% to 100%.
However, during the second charge, the pots were more abruptly handled
as they were emptied and fume collection dropped off to 50% to 60% in
some instances.
Also providing some measure of reducing fume generation above the
hot slag charge hole were two air nozzles which direct air into the
-------
51
charge hole opening. The nozzles appeared to have had varied effective-
ness, depending on the conditions within the furnace and the presence or
absence of slag material which had hung up in the charge opening.
Besides operator variation in handling the pots, other factors which
influence the magnitude of the charge emissions are furnace pressure
fluctuations, ventilating air suction pressure, ventilating air flow
rate, the physical arrangement of the duct, and how rigidly the skull
had set up in the pot.
Some fugitive emissions evolved from the cold slag charging chute
at the top of the furnace. These emissions are reduced by an air nozzle
which in this case was located just inside the furnace. This mechanism
did not appear to be operating correctly as significant fumes were
observed to be escaping. The leaks from the furnace walls were uncon-
trolled.
The charging/heating cycle takes approximately 60 to 75 minutes.
The cycle is reportedly longer than for other zinc fuming furnaces;
since ASARCO stockpiles only a few pots of blast furnace slag prior to
beginning a charge, additional pots must be awaited from the blast
furnace as the charge is completed.
After all the slag has been added to the furnace, the furnace
enters a fuming stage in which as much zinc is removed from the molten
bath as is feasible. In this stage, the amount of air added is decreased
and the amount of pulverized coal added is increased compared to that
added in the charging stage.
Tertiary air, to oxidize the lead and zinc vapor, is added through
the two nozzles directing air into the charge opening and through the
single nozzle directing air into the mined slag chute. The fuming cycle
takes from 60 to 90 minutes.
-------
52
Fugitive emissions were observed to emanate from the furnace walls.
The walls of the furnace are a series of water jackets which are bolted
together. In some cases, the gaps between the furnace jackets caused
significant emissions; these gaps were wide enough to allow a view of
the flames from the molten bath inside. As the furnace pressure fluctuates,
the jackets vibrate, thereby allowing fumes to escape. The Company
indicated that the seams are caulked with asbestos rope, Kaolwood* rope
or Si lite* 100 sealer as needed.
The quantity of emissions appears to be a function of maintenance
practices. In some cases, the furnace leaks were in areas of extremely
tight working space and proper caulking would be understandably difficult.
At the end of the fuming cycle, the furnace is tapped through a set
of two tapping holes to remove spent slag. A hood is lowered over the
slag tap launder and appropriate dampers are positioned to allow the
ventilating air to take suction on the tapping line. During the inspection
it took about 10 to 15 minutes to tap the zinc fuming furnace.
The fugitive emissions from the tapping operation were relatively
minor. There was some escape of fumes between the hood and the furnace.
Fugitive Emissions Controls
The fugitive emissions resulting from the zinc fuming, charging,
and tapping operation are collected by hoods over the fuming and tapping
areas, respectively. The charging area uses an overhanging hood with a
collection area of 11 m (118 ft2) and an inlet gas velocity of 64 m
(211 ft)/min. The ventilation flowrate is 730 act. m3/min (25,890 acfm)
-at 90°C and 650 mm Hg.
Brand name
-------
53
The fumes which are collected in the hood are vented to the suction
of the zinc oxide baghouse fan. The baghouse is a shaker-type baghouse
with Nomex* bags. The bag area is 9,100 m2 (98,400 ft2). The total
o
flowrate through the bags is 4,600 act. m /min (164,000 acfm) with a
reported particulate removal efficiency of 99.7% by weight.
The Company has also reported that some reduction in fugitive
emissions has been accomplished by increasing the available draft at the
furnace.11 The Company has done this by installing a larger diameter
impeller in the baghouse fan. This also required increasing the fan
motor from 380 to 530 kW (500 to 700 hp).
ASARCO has stated that the ventilation hoods, ductwork, new venti-
lation fan, and larger baghouse fan impeller and motor were installed at
a cost of $236,000. The ventilation fan and ductwork were put in service
in March 1974. The installation and remodeling of the hoods and the
installation of the larger baghouse fan impeller and motor were completed
in December 1975.
The Company has indicated that future plans are to improve the
baghouse fan volume and extend the charge area hood. Improving the
baghouse fan volume will, in part, be accomplished by reducing the
pressure loss at the junction where the ventilation air flow joins with
the main offgas stream. No information was provided as to the projected
completion dates and costs of these modifications.
* Brand name
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54
ASARCO - TEXAS*
Process Description
The ASARCO lead smelter is inside the city limits of El Paso,
Texas. It was originally built in 1887 but has undergone extensive
modifications since then. A custom smelter, it processes ores from
locations throughout the world.
A block diagram showing the overall smelter operation is presented
in Figure 9. Six updraft sinter machines receive concentrates, residues,
limestone, silica and coke and produces a granular product (sinter)
suitable for charging to a blast furnace where it is reduced with coke
and scrap iron to produce a crude lead bullion. The crude bullion is
processed at a dressing plant and casting to produce a 99% lead product
which is ready for final refining. Copper matte, and a speiss (Cu, As,
Sb) are transferred to the copper department for further processing.
The zinc fuming plant was constructed in 1948. This plant is
essentially a batch operation in which hot slag from the blast furnace
and cold slag held over from earlier operations are smelted to produce
zinc oxide, lead oxide, and copper matte. The slag enters a furnace
with a coal and air mixture and is heated by combustion of the coal
under reducing conditions. The zinc and lead initially present in the
slag are reduced, vaporized, re-oxidized and carried with the offgas
through a cooling system by an induced draft fan. The offgas passes in
series through a waste heat boiler, balloon flue, cooling tower and
baghouse. The baghouse exhaust gas is discharged to a stack. The fume
collected in the flues, cooling tower and baghouse are treated in a
deleading kiln which separates the lead and zinc oxides. The slag from
the zinc fuming furnace is tapped into a gas-fired holding furnace where
copper matte and waste slag are separated.
* Information in this section is derived from reference 12.
-------
PURCHASED ORES AND CONCENTRATES (26% LEAD)
55
SIX DWIGHT LLOYD SINTERING MACHINES
GASES
D & L BAGHOUSE
1760 DYNEL BAGS
Silt
TER
BLAST FURNACES
18 in DIA X 30 FT LONG
1 » t
I SLAG LEAD GASES
t t
DUST TO CLEAN GAS
BLAST FURNACES TO 610 ft CHIMNEY
ZINC FUMING FURNACE
1
L
1 f '
GASES AND FUME SLAG LEAD
•
1 'i
WASTE HEAT BOILER HOLDING FURNACE
COOL
72,000 Ib/hr I
MG TUBES TO DUMP
\
BAGHOUSE
960 ORLON BAGS
18 in DIA X 30 ft LONG
CLEA
Y GAS IMPURE ZINC OXIDE
»
DELEADING KILNS
DROSS ING KETTLE
60 tons CAP
DROSS
ERBERATORY
FURNACE
28 ft LONG X 8 ft 4 in WIDE
MATTE
1
TO COPPER
7 ft DIA x 75 ft LONG
1
SPE1SS L
1
DEPT.
t
IAD GASES
L_
1
L 1 CASTING KETTLE B.F. BAGHOUSE
GASES;* FUME ZINC OXIDE 125 ton EAP 960 WOOD BAGS
BAGHOUSE REFINERY
1
300 ft
160 ORLON BAGS
18 in DIA x 30 ft LONG
I
CLEAN GAS
I
8 ton BLOCKS
99% LEAD
TO REFINERY
18 in DIA X 30 ft
I LONG
CLEAN GAS
TO CHIMNEYS
HIMNEY
Figure 9.
Process Flow Diagram for Lead and Zinc
Department, ASARCO-E1 Paso Smelter ing Works
-------
56
A process flow diagram of the zinc fuming plant, prepared during
the inspection, is shown in Figure 10.
Table 10 shows the operating design data for the zinc fuming plant
operation. The plant processes approximately 19.6 m. tons (21 tons)/hr
of blast furnace slag and 3.0 m. tons (3.3 tons)/hr of cold slag, producing
approximately 3.8 m. tons (42 tons)/hr of zinc and lead oxide fume. The
furnace is a bolted water-wall furnace with a capacity of approximately
54 m. tons (60 tons). The zinc fuming plant handles 10 to 12 charges
per day. The total cycle time for the process is approximately 120
minutes.
Process and Emissions Observations
The zinc fuming furnace was observed throughout its full cycle of
operation during the February 3, 1977 inspection. Observations were
made as to the process steps conducted, where fugitive emissions occurred,
how the emissions were collected and/or controlled, the effectiveness of
the collection/control systems, and what factors appeared to most in-
fluence the emissions and their control.
The zinc fuming furnace is charged with 11 m. ton (12 ton) capacity
pots of blast furnace slag which are emptied by crane into a furnace
charging chute and with cold slag which is discharged from a continuous
conveyor into the same charge chute. Pulverized coal and air are blown
through two rows of tuyeres into the bottom of the furnace. The crane
transports each pot to a bumper block on the ground adjacent to the
fuming furnace. The pots are repeatedly banged against the bumper to
break up skulls, or hardened material, which are formed as the pots
cool. The pots are then lifted over the charge area hole and emptied
into the furnace. It takes about 2 to 5 minutes to empty each pot.
Three to five pots are emptied into the furnace for a given charge.
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57
COLD
SLAG
COAL
VENT FAN
JSLAG 1 1
i
HOLDING
FURNACE
-4
WASTE
HEAT
BOILER
SLAG
COPPER
MATTE
BOILER FANS (2)
INTERMEDIATE FANS (2)
O
VENT FAN
ZnO PRODUCT
TO ZINC RECOVERY
PbO PRODUCT
TO LEAD PLANT
Figure 10. Process Flow Diagram for Zinc Fuming Plant,
Lead Department, ASARCO-E1 Paso Smeltering Works
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58
Table 10
OPERATING AND DESIGN INFORMATION
ASARCO - TEXAS ZINC FUMING PLANT12
OPERATING
Average cycle times
Charging/heating
Fuming
Tapping
Charges/day
Material flowrates
Blast furnace slag
Mine slag
Coal
Fume collected
Zinc/lead recovery
Average lead in input slag
Average lead in output slag
Average zinc in input slag
Average zinc in output slag
Air flowrate, charging
(minutes)
25
80
15
10-12
(m.tons/hr) (tons/hr)
19.6 21.6
3.0 3.3
3.8 4.2
3.8 4.2
(% by weight)
1
0
12-16
0-2
3
430 act. m /min.
FURNACE
Type water-wall (bolted)
Capacity 59.5 tons 54 m.tons
Dimensions 6.0 x 2.1 x 10.2 m (19.7 x 6.9 x 33.5
Tuyeres 26 on north side and 24 on south
side at variable centers, 14 cm
from bottom, 5 cm diameter
Charging Hot slag is charged through charge hole on south side
of furnace approximately 3.7 m from top of furnace.
Cold slag is charged by conveyor into a charge hole
chute at the top of the furnace.
ft)
-------
59
The major fume emissions during the charging/heating cycle came
from the slag pots when they were banged against the bumper block and
emptied during the charge. These emissions occurred chiefly near the
bumper block and at the charge chute. Some minor leakage of fumes was
also noted from the furnace walls. No leakage was observed from the
waste heat boiler lance doors.
After all the hot slag had been added to the furnace, the fuming
stage commences, during which as much zinc as is feasible is removed
from the molten bath. The amount of air added to the furnace is main-
tained fairly constant although the amount of pulverized coal added may
be varied to maintain steam production within proper limits. Tertiary
air, to oxidize the lead and zinc vapor, is added through the charge
opening which is designed to operate at slightly negative pressures.
During the fuming cycle, significant fugitive emissions were
observed from the charge chute. These emissions consisted of high-
opacity, pulse-like emissions which varied from about one second to over
a minute in duration. The Company indicated that this was due to a
malfunctioning soot blower. When particulate deposits were formed on
the boiler tubes, the pressure at the charge chute became positive and,
as a result, fumes were emitted. Leaks from furnace walls and waste
heat boiler lance doors were very insignificant.
At the end of the fuming cycle, the furnace is tapped through a
tapping hole and chute. The chute is hooded and vented to a separate
baghouse. During the inspection it took about 10 minutes to tap the
zinc fuming furnace. The fugitive emissions from the tapping operation
were relatively minor. There was some escape of fumes between the hood
and the furnace.
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60
Fugitive Emissions Controls
The Company currently has no fugitive emission controls for the
charging area of the zinc fuming furnace. However, the Company intends
to enclose the entire building in which the fuming furnace is located.
The fugitive emissions, including charging emissions and other fugitive
emissions from the zinc fuming furnace, will be collected in a venti-
lation system to be located in the roof of the building. The collected
fumes will be ventilated to a new baghouse for treatment. The Company
is designing the system for 16,000 act. m3/min (580,000 acfm) flowrate.
The collection and treatment system is designed to be operational in
August 1977 and is estimated to cost $8.5 million.
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61
REFERENCES
1. Written correspondence, G. M. Baker, Bunker Hill Company to C. V.
Smith, Jr., USEPA-Region X, April 7, 1976.
2. Atmospheric Emission Evaluation at the Bunker Hill Company, Kellogg,
Idaho, Valentine, Fisher and Tomlinson, Seattle, Wash. Feb. 7,
1975.
3. Bunker Hill Facilities description, Bunker Hill Company, 1975 (est.)
4. Personal communication and facility inspection, R. W. Grosser, Jr.
et al., Bunker Hill Co., and R. J. Gosik, USEPA-NEIC, Aug. 16-19,
1976.
5. Written correspondence with attachments, R. W. Crosser, Jr., Bunker
Hill Co. to R. J. Gosik, USEPA-NEIC, Oct. 6, 1976.
6. Written correspondence, R. W. Crosser, Jr., Bunker Hill Co. to R.
J. Gosik, USEPA-NEIC, Jan. 24, 1977.
7. Personal communication and facility inspection, R. W. Crosser, Jr.,
et al., Bunker Hill Co., and R. J. Gosik, USEPA-NEIC, March 1-2,
1977.
8. Written correspondence with attachments, T. H. Coughlin, Bunker
Hill Co., March 1, 1977.
9. Source Test Report (p. 1 and 15), Alsid, Snowden and Associates,
Bellevue, Wash., Aug. 25, 1976.
10. In-Plant Fugitive Dust Emission Measurements - Bunker Hill Lead
Smelter, G. A. Jutze and L. A. Elfers, PEDCo - Environmental
Specialists, Inc., Cincinnati, Ohio, Sept. 30, 1975.
11. Personal communication and facility inspection, S. R. Gasser, et
al., ASARCO Inc., East Helena Plant, and R. J. Gosik, EPA-NEIC,
July 22, 1976.
12. Personal communication and facility inspection, D. P. Hall et al.,
ASARCO Inc., El Paso Smelting Works, and R. J. Gosik, EPA-NEIC,
Feb. 3, 1977.
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62
BIBLIOGRAPHY
American Conference of Governmental Industrial Hygienists, Indus-
trial Ventilation, Ann Arbor, Michigan, 1974.
Billing, C. E., et. al, Handbook of Fabric Filter Technology, Vol.
II, NTIS PB 200 648.
Cotterill, C. H. and Cigan, J. M. (ed.), AIME World Symposium on
Mining and Metallurgy of Lead and Zinc, New York, N.Y. 1970.
Economic Indicators, Chem. Eng., March 14, 1977.
IGCI, Air Pollution Control Technology and Costs: Seven Selected
Emission Sources, NTIS PB 245 065, Springfield, Va., December,
1974.
Peters, M. S. and Timmerhaus, K. D., Plant Design and Economics for
Chemical Engineers, New York, N.Y. 1968.
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APPENDICES
A 113 Notice of Violation
B Idaho Air Regulations F and
C Calculations
-------
APPENDIX A
113 NOTICE OF VIOLATION
BUNKER HILL LEAD SMELTER
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i:
2
3 '
4
6
6
;i
,j I. UNITLU SlA'iES ENVIRONHhinVVL PROTECTION AGENCY
i ""»
fi i' Ucr.lon X
•• 1200 Six ill AVCIU.C
j
ji) | ScaLllu, 'rtjsruiujLon
11
;:; TiiL : ifTL:. oir )
12 ' ) No. X75-OJ-21-113
f". i'.111 \ Ac I rroccoJinp. )
J3 i ) COMI'LiAiJl'.. 'OiU)k.K
; 5 113(..;(L) [-'.2 I'bCA § Iti57c-3(a)(])) ;
14 ,; >
,| Inc LUM..LI- Hill Co..pj.iy )
15 • )
respondent. )
16 .j ! )
17
"i1: ''.'.• ilnnixui Mill Coi.i,i.-...y
:.- •; r.- . ik'\ 29
ij K> '. loj^;, Id.ii o 83S37
IS; !! Aim: Hi:. Jar.ics llalii1), Trcuiucnl
•.•n:.si.anl to section H3(j)(l) of tliu Cic--.i Air Act (hoi01.-..iflor
21 !. rcfcii'O to as the ACL), LIIU Rcgion.il Adr..iiusLtatov now iiiuls Jfa foilouj,:
2° AOMit.isiiuM'or.'s rr-iJi" ^
23 ' L. Ilic bunker Hill c,ui.ipany, i:cbpom!c:r., operates a le.m and /.Jnc
21 ' j.-_. . .ii.i .1 .M I...LI. j i ..laLiO'- h.iLili i., .1. I-..LI. c...:.... .1.1.:- :....«.,oct in
25 ; :ci;uLi ioa under Lnc Clc.in Ail ACL.
i!
26 II J. 'ilic Ko'-poi-Ji-iii 's npoi.iLii.Mi!. aL s.iu1 f.iciJity .iri- sn'ijcv.1 l>i
i
'^7 !' • c-jui •: UMI I of Lho Su.U' of Id.ilio't. Kulc- lnr Llio CmiLii.il ••! ALf
'JS i /c-lJi.1. i. i-, i'.u-t of Li.c lii.ilio SLaLo Air iMpli-n-oiUALion i'lan. liiaL i\ ,;J-
2'J . ,j l.iuo. u-sLriclh llic CCIIOIMLIOII ul finjilivc ilust -i.n. LC .,ui !•••., in ,MIL,
< !i
30 -. .I..TL '..'J Luason.ibU1 iu-uc.u-.Lirns i.ii.ill b_- t.i' c.i to p! C'vnL ,' U'ticu l.ito
31 ; ii-.'.lii' lion bcciJ'Kinr airborne."
Ii
32 • f.0.1'.;1, I.'X'I. O.:!i' !! - I'.'v.o 1 o.r f>
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1
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3
4
6
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7
8
9
10
11
12
13
14
15
16
17
16
19
20
21
22
23
24
25
26
27
2?
29
30
31
32
3. H.iscd on the available in . nation, it'is Jecci Minimi LliaL
Respondent h.ib noi taken nil leasonablc precautions to pi event. particulatu
matter from bccor:iny airborne.
ft. Respondent wan notified oi its Iai]i.ic to tako such pn.iMi.it unib
l|
bj ;\ :.otii.e ol" Violation directed to it, attention Mr. Jnr.ies llallcy,
Prcsidc-.it, on Ju.ie 17, 1975.
5. Sucli violations were observed to continue for more than 30 days
aft or t'.-.u date of the Notice of Violation.
6. Respondent was afforded and exercised the opportunity to confer
| concerni.ii; tho violation required by section 113(a)(i») of the Cloaii Air
I Act on August 29, 1975 when Respondent's representatives met WIL!I
i Rcjjion.iJ AJinini:.trator Cliffnid V. Snith, Jr., the AdminL.str.ntor's
i celct;nti'c, in« tlvo Seattle Region X offices.
il
j1 AIL or a review of the relevant facts, jpcludii-.g the seir.n.'.isj.iess .'.•
l!
; r.iirl vii-l.itioMS, "all i;ood uiith efforts to cui.'ply, .ind the re<_i>id ol t!ie
st 29 coiiteronce regardins this i..attcr, it is hereby
O;\JJLUI:D .-1.5 follows:
I. No latei I linn 30 il.iys after each d.iU: spi-cifted ho low, tho
Respondent sli.ill notify the LPA Regional Office, in writing, of the
j] Respondent's achievement or nnnnch levemcnt of the following activities
!i tho Kospoiiiit-nt is hereby dirocicd tJ .•(.liiovc:
ii. Si.iterinj1, pri'Cii.s .iro.i (inc Ludii;,'. nn.i. cntr.ite fc.\:i\
(1) Submit n description and initiate construction ol
nr. 'iiul f. ic LI it icb c.i p.i!) J i- of pi uv Lil LIU; .idciiu.itc (.•xli.iui.L c.ip.ihi I i I;.
j to j l).ii_,licm:-,o 01 biij'.houucs or other >ippro|ir Latu control syati-.n for
i
j the soin.-fs 1 is,ted l-clow by October Jl, 1973.
- :• i-" 7 ol (<
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1
2
3
4
6
6
7
8
9
10
11
12
13
14
15
Iti
IT
IS
19
20
21
22
2J
il
25
2C,
2V
2S
2-J
(a) Return sir' . conveyor belt open transfer point.
f . .
(b) Kcturn sinter durip to north (phase 2) storage
tank.
(c) Return sinter dunp to cast (pluist- I) stor.ii;c
Hi nk.
(J) Concentrate bin conveyor bait 'nuil.l-n;1. vent
fan c.\!iaiibL.
(c) West bedding roon Ian exhaust.
(f) Last beddiny room Ian c.xhaubt.
({•,) Sinter product line (open conveyor belt nreus.)
(li) Return sinter, south to north jnd wcs: to east
conveyor belts.
(i) Tr.insfcr points JiiJ conveyor belt., siiviuu the
oiit-£lo\.' fro.j tlics pn.isc 1 storage tdi'.'.v.
(j) IL tins [or points .liul ro.ucyor lu-lti- ^civLiii; tlic
oucllow Iron the piia-r.-s 2 storayo tank..
(2) Coiiplctc consLiuction o£ •iilJ have ilucting aid
ii-. dubcrilicu :ibove in Tu]l opciMtioi/ by' M.iroli 31, l'J7».
b. jilast K»r».ice Aio.i.
(1) • Select which ol the two alternative ncd'.ods, iistc.l
•jolow t'no 'Junker Hill Company vj.ll use to contiol fugitive emissions from
•'. L'.u tol'a -ini; sources by Novcribor 1, 1975.
ij (a) IJLa.'-t furittico Ceod area (upset).
1 (li) 1'u'aut iuiii 11.0 ici.-i v.-i-.ts.
I!
!• (c) JJIast furnace feed conveyor s>ys.tc-i.i.
i
! OptJon A. Adi! onto 1 x i si t J ny hood Lnj; anil ihu-t LP.J; to
ii
I;
I1 capture c .cuiis fugitive crimsions fiou the .-iimrccs lifted irn:.i.d uitcl}
1 .iiiovc .inn i-onvoy Lhoia LO .1 new iM^liousc or ot'.u r fij icirini; sjij:o..i.
31
31.!
'','.v II'1.1..Mi Oi"i!.ii - I1-'",1."1 3 of 0
-------
•
Option's. .Modify u. i -place Llic existing flue systcu and
| Curry out necessary upgrading Lo Llic existing ruin bagliou^e to r.ainL.i 1:1
i>
Ij ailecujLc draft such that eruptions and other fugitive ein$s><.iuns> froi.i
'!
ii tlio sources listec immediately above are c.xluu.stcd and ductcc! through
1
2
Curry
.3 Ij ailec.ua
4 !
i
5
the so
li.l: C,0,
6
i
i
7 ij l.i'non.
i>
8 i
9
10
11
12 !!
13 J!
" i
«• I
16
! taken.
17 i
» '
i
lv
20
21 jj
22
23
24
i
25 1
II
i
i
2" ( tunnel
*J* 1 .mi! cv.-
i
•
29 i •""' •••"
(?) If Option A ib chosen, the following stops !>:i.ill be
(a) Submit an engineering plan for addiUoiis to
existing iiooding and the installation of new
control equipment by Dcccrber 31, 1975.
(b) iiegi.i constiuction by ilay 1, 1976.
(c) Submit a report of progress by Septea^or 30, j^Tf
(d) Conplutc cunstrnetiun r.nd opcrtitc uc]ulpiLeiit in
conpliaiicc by Tlarch 31, 1977.
(J) If uption U is c-lu'bcu, the following i,tcp.s t,h.ill he
(a) Submit an engineering plan for wodjJ.'ic.iLions of
'
31
I i-iuiirol
or additions to existing conLio1 i ^n'Lpi.ent ur
i
the instail.ition of ni.v coniiol ei|uL|... I.-.IL (i!i.it
will accor.plish Option U) by Uccciul^cr Jl, 19."j.
(b) Begin construction by Marcli 31, 1976.
(c) Submit a report of p:ogress by Scptei.ihor 30, 1975
(t!) Subnit :i report of progress by Jlarch 3'L, 1977.
(e) Complete LOiistrucLijn >ind in cop'.plitincc by
July 31, J977.
CO Ucductlon of cnLst-ions from Llic bl^ist furn.icc sin'er
•.i.:iHigli ii'.sLall.ition of faciliLics to provide jJjqu.iLo capture
Lr;l of f.i,;ilivc d;ist by in->l.:lling noi_essary djctinr, '.-.ooilin;1.
ijiuitc e\huii-L c.ip.iliility to .1 h.igiuuisc 01 othov .ippLOpri.iLi;
.:y:.ti-in sh.il I r«)|Jow Liu- sclmltiU* In-low:
f.. -li'i.iA-. .: 0!ii)i •{ - r..i •- /•
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1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
1C
17
15
19
20
21
22
23
24
25
20
(a) .Begin con . accion by October 31, 1975.
(b) Submit engineering evaluation of cncirical
suppressant system by March 31, 1976.
(c) Complete construction and ir. final compliance
by October 1, ]97C.
c. Zinc Fiii'.^ni; Tun-ace.
(1) Provide ai'ecuiate exhaust capability lo a l-.i^hou-.e or
ba^.liouscs or other .ippropriatc control system \"or the ::itic Cui.'jni; i.'i—
r.ace charging area in accordance with the following schedule:
(a) Submit an engineering plan for the control
s.ystur.1 by December 31, 1975.
(b) Issue purchase orders for control o(|UJi>3ei- *
January 31, 1976.
(c) Submit a ronort of progress o.i i>e|>tcr.ber 30,
1976.
(d) CoupJi'tc construction of and have facilities
described Jn I.e. (I)1, above, in full operation
by December 31, 1970.
(2) The /.iiiv. Himinj; fuinaie .••ii.ill be 1.1.1 int.i invd and
operated in .1 IcaU-Ircc condition by Dccei.'.bcr 31, 1975.
(I 'd. Silxvr HuUiri .
jj
(1) St.ut construction of necessary ducting and faciii-
i1
Jl ties CO provjdc adequate cxn.itist capability to a b.ighouse or bji;'nouucs
jj or other appropriate contiol system for the silver rcturt bu^ld.Jag
roof ve.itri by Mari.h 3J, 1970.
(2) CoupJoLu conLti-action of and have the ducting and
iaci.1.11 .•:-. de^cr:.5L-d an l.il.(l) ribovc in fulJ operation by Dece.ribcr 31,
'I
29
30
31
3'J
I e. I.e.id Ket iiic-ry.
!i
I.. ".rLl.V • .: Oui)LR - I1 5 <>£ (•
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1
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3
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6
7
8
9
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12
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14
15
16
17
16
19
20
21
22
23
24
25
26
27
28
30
31
3.'
(1) Submit an cngi ing report specifying necessary
ducting and facilities to provide adequate exhaust capability to a
b:.£hcuoe or baghouscs or other appropriate; control system for control
| rf fugitive emission:, from the lead refinery roof vcnti. by M.irrh 31, I97d.
]| (2) Issue purchase orders for control ci|uip.r.cnt by.
!i
i! i!ay 3i, i*J76.
(3) Ciu.ir.iCiicc construction of necessaiy ducting and
j facilities, by Scptonbcr 30, 1976.
(O Submit a report of progress by June 30, 1977.
(5) Submit a report of progress by January 31, 1977.
(6) I'ir.al compliance by July 31, 1970.
TiiO notification mentioned above shall he made to:
i
|i
Ms. Nora MiCoc, Chief
Air Ci»-:i'lL.ir.ce Kt.'.luation Section
U.S. F..i\ i ra.ricntal Protection Aj.er.cy
It.iil Pi op 513
1200 S..\tn Avenue
Seattle, Wab'uington 98101
Tlie Respondent'shall take all reasonable steps, ini'ludin^ pioper
c.ainten.nicc and operation of nil existing emission control devices, to
ii control regulated cnissions during the period covered by this Order.
i. Nothing in tnis Order shall prevent the Adrninistiator from cxercis^n:;
I
! those emergency pcvers hcJJ pursuart to section 303 of the Clean Air
ll
ji Act [bc of dotoriiininj: ;a) whcti'.cr progress is bi.ing n-.aJVi as
| cxpeditiuitsly as practicable; and (b) the actual level of emissions
'i during the period covered by this Orucr, the Rcsponucnt shal]: (1)
S Maintain buch records, (2) install, use, anri nuintaiii buch im-.i i to ring
.1
end s.i..plinf. e<|u_pnent, (3) n.il.c sui.li fui ther rcportsi, and (A) allow such
1. iv.tn of t!1.^ said facility and of records peitaining tin.rcto ab
'I the Uc;',ion.il Adr.inistr.itor rn.iy r
: io-:i': i •••'.!. '.-Knir; -
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APPENDIX B
IDAHO AIR REGULATIONS F and H
-------
P
REGULATIONS F and H
DEPARTMENT OF
HEALTH AND WELFARE
-------
RUI£S AND REGULA"' "MS FOR THE CCKTROL OF AIR POLLUTICN PI IDAHO
LEGAL AUTHORITY
Tlie Board of Environmental Protection and Health, pursuant to the authority granted
by Chapter 1, Title. 39, Idaho Code, and Chapter 52, Title 67, Idaho Code, did adopt
the following Rules and Regulations for the Control of Air Pollution in Idaho on
October 25, 1972. Regulations C and Q ware amended by the Board of Environmental
and Conrounity Services on April~ll, 1974 and did determine the effective date to be
April 11, 1974. Regulation T was adopted and Regulation A attended by the Board of
Environmental and Connunity Services on June 20, 1974, and the Board determined the
effective date to be June 20, 1974. Regulation U was adopted and Regulation A was
amended by the Board of Health and Welfare on December 5, 1974, and the Board deter-
mined the effective date to be December 5,_1974..A Regulation S was revised on Janu-
ary ?., 1975, by the Board of HealEh ancflrtblf are , and the Board determined the effective
date to be January 3, 1975. Regulation U_ was amended on September 18, 1975, and
became effective on October 14, 1975. 2
A. GENERAL PROVISIONS ...............................
B. AIR POLLUTION EMERGENCY REGULATION .......................
........ 21
C. AMBIENT AIR QUALITY STANDARDS ..................
D. REGULATION FOR CONTROL OF OPEN BURNING ............. • .......
E. REGULATION FOR CONTROL OF SMOKE OR OTHER VISIBLE EMISSION ........... 27
F. REGULATION FOR CONTROL OF FUGITIVE DUST ....................
G. REGULATION FOR CONTROL OF PARTICULATE EMISSIONS FROM FUEL BURNING EQUIPMENT . . 29
H. REGULATION FOR CONTROL OF PARTICULATE EMISSIONS FROM INDUSTRIAL PROCESSES ... 31
33
I. REGULATION FOR SULFUR CONTENT OF FUEL ....................
• J. REGULATION FOR CONTROL OF FLUORIDE EMISSIONS ................. '
........ 35
K. REGULATION FOR CONTROL OF ODORS ................
*r
L. REGULATION FOR CONTROL OF INCINERATORS .....................
M. REGULATION FOR CONTROL OF MOTOR VEHICLE EMISSIONS ............... 37
38
N. REGULATION FOR CONTROL OF HOT-MIX ASPHALT PLANTS ....... . .........
0. REGULATION FOR CONTROL OF KRAFT PULPING MILLS ................. 39
P. REGULATION FOR CONTROL OF WIGWAM BURNERS ....................
Q. REGULATION FOR CONTROL OF RENDERING PLANTS ................... *5
R. REGULATION FOR CONTROL OF SULFUR OXIDES EMISSIONS FROM SULFURIC ACID PLANTS . . 45A
S. REGULATION FOR CONTROL OF SULFUR OXIDE EMISSIONS FROM COMBINED ZINC/LEAD ^ ^ ^
SMELTER OPERATIONS ...............................
T. REGULATION FOR AIR POLLUTION SOURCE PERMITS .................. 63
U. STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES .............. 66
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F. REGULATION FOR CONTROL OF FUGITIVE DUST
SECTION 1
Purpose
The purpose of this regulation is to require that all reasonable
precautions be taken to prevent the generation of fugitive dust.
SECTION 2
General Rules
All reasonable precautions shall be taken to prevent particulate
matter from becoming airborne. In determining what is reasonable,
consideration will be given to factors such as the proximity of dust
emitting operations to human habitations and/or activities and atmos-
pheric conditions which might affect the movement of particulate matter.
Some of the reasonable precautions may include, but are not limited to,
the following:
A. Use, where possible, of water or chemicals for control of dust in
the demolition of existing buildings or structures, construction
operations, the grading of roads, or the clearing of land.
B. Application of asphalt, oil, water or suitable chemicals to, or
covering of dirt roads, material stockpiles, and other surfaces
which can create dusts.
C. Installation and use of hoods, fans and fabric filters or equiv-
alent systems to enclose and vent the handling of duscy materials.
Adequate containment methods should be employed during sandblast-
ing or other operations.
D. Covering, at all times when in motion, open bodied trucks trans-
porting materials likely to give rise to airborne dusts.
E. Conducting of agricultural practices such as tilling of land,
application of fertilizers, etc., in such a manner as to limit
dust from becoming airborne.
F. Paving of roadways and their maintenance in a clean condition.
G. Prompt removal of earth or other stored material from streets.
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11. RHCULATlON FOR CONTROL OK PARTICIPATE EMISSIONS FROM INDUSTRIAL
PROCESSES
SECTION 1
PURPOSE
The purpose of this rep.ulation is to establish participate emission
limits for any operation, process or activity not identified by name and
specifically regulated elsewhere in these rules and regulations, and shall
apply during normal operation.
SECTION 2
EMISSION LIMITATIONS
No person shall cause, suffer, allow or permit the emission of p.ir-
tlculate matter to the atmosphere from any process or process equipment in
excess of the amount shown in Table VII-2 for the process weight rate
allocated to such a process or process equipment. The rate of emission shall
be the total of all emission points from the source.
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TABU: vn-2
ALLOWABLE BATE OF jaassicw BASED CN
-yy) ,un>mfScjaiUl*.T!nrF
?rcce
Lb/tir
••••• ~ 1 1 •" '
100
200
400
600
COO
1,000
1,500
2,000
2,500
3.000
3,500
4,000
5,000
6.000
7.000
8,000
9,000
10.000
12,000
rnyviM«Tffj,'BWff'iJiiiHfrifHon1
to 3 Weight
Rate
Toao/Er
1 1 mi ' "
0.05
0.10
0.20
0.30
0*60
0.50
0.7S
1.00
1.25
1.50
1.75
2.00
2.50
3.00
3.50
4.00
4.50
5.00
6.00
PROCESS WEIGHT RATE*
[gfpf Jjggy rff-'rt"*8'1*"^*13'" •**
Rato of
Eaiooicn
Lb/Iir
0.551
0.877
1.40
1.83
2.22
2.53
3.38
4.10
4.76
5.38
5.96
6.52
7.58
8.56
9.49
10.4
11.2
12.0
13.6
Procoos Weight
Rato
Lb/Er
16,000
18,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
100,000
120,000
140.000
160,000
200,000
1,000,000
2,000.000
6,000,000
ftAft.artt^nfr'.fmafmyt^attswt
Tons/Hr
8.00
9.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
45.00
50.00
60.00
70.00
80.00
100.00
500.00
1,000.00
3,000.00
»«HUJHH[fl.Jll«»g|| |||. IH-I 1 w^imrojnram™i.iim.».«m —
*lnterpolation of the data in this table for process weight raj
Ib/hr shall be accomplished by use of the equation E - *.10 P*
in i iinir'ii'fftKHPn*"**mJ**i|g-i--iF[ftym
9£2jglBIMU>SMVM*«^BB*-«>^B*^»H*Mi*^v"1"'
Rate of
Balooton
Lb/Hr
16.5
17.9
19.2
25.2
30.5
35.4
40.0
41.3
42.5
43.6
44.6
46.3
47.8
49.0
51.2
69.0
77.6
92.7
j^iMj«MfPff;MUJfliftffftmW'tff?**!!ai
.63. up to 60,000
'•"7, and inter-
^ _ J *& dK«*^« f* a m ^ ¥
poatlon an cxrHp
60,000 Ib/hr shall be accompliflhoii by use of the equation:
E « 55.0
- 40, whar* F " fata of etnlosion In Ib/hr end
P • procooa voioht roto In tcsno/hr.
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APPENDIX C
CALCULATIONS
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PROJECT: Zinc Fuming Furnace, Bunker Hill Lead Smelter
SUBJECT: ZnO Baghouse Pressure Drop with an Additional Section
NAME: R. Gosik EPA/NEIC
DATE: 3/29/77
Problem: Determine the decrease in pressure drop for the ZnO baghouse
if an additional section is added
References: 1. Handbook of Fabric Filter Technology, Vol. I Fabric
Filter Systems Study, Dec., 1970, C. E. Billings et al
2. Meeting with Bunker Hill Co. and EPA, 3/1/77
Assumptions: As noted in calculations
Calculations: 1. Existing baghouse AP ^ 4 in. WG [Ref. 2]
2. Adding an additional section to the existing 5-section
baghouse will decrease the filtering velocity by 5/6
3. The pressure drop for the baghouse is given by the
following equation
Ap(t) = K? . CiV2t [Ref. 1, p.2-160]
* TTooo
where ^ = resistance coefficient, C. = inlet dust
concentration, v = filtering velocity, t = time
4. At any given time (t) the difference due to the addition
of another baghouse section is given as
APnew = V2new (X Void)2 .7
*Pold " V2old " Void2
therefore in the case where APold = 4 in W.G.
APnew =0.7 x 4 in W.G. = 2.8 in W.G.
o£ a reduction of up to 1.2 in W.G. can be expected
if the baghouse is expanded by 1 section
-------
PROJECT: Zinc Fuming Furnace, Bunker Hill Lead Smelter
SUBJECT: Hood and ventilation requirements for charging area
NAME: R. Gosik EPA/NEIC
DATE; 3/28/77
Problem: Determine the hood size, and ventilation requirements for
the following:
1. Dual-modified canopy hoods (see attached sketch)
2. Dual-side draft hoods
3. Single overhead canopy
4. Single roof-top collection
References: 1. Industrial ventilation, 13th Edition, 1974, American
Conference of Governmental Industrial Hygienists
2. Bunker Hill Co. drawing S53-731, Mar. 6, 1962, Fuming
Plant Ventilation Fan and Hooding for Fuming Furnace
3. Bunker Hill Co. drawing S53-732, Mar. 5, 1962, Fuming
Plant Ventilation Fan and Hooding for Fuming Furnace
4. Attached sketch [Fig. 5]
Assumptions: As noted in calculations
Calculations: 1. Dual-modified canopy hoods
a. Arrangements: defined by space restrictions
see attached sketch [Fig. 5]
b. Flowrate reg'd (p. 4-18, ref. 1)
Q = 1.4 PDV where P = 30 ft, D = 8 ft
(dist. from top of hood to
1/2 the way between the hopper
and pot), V = 240 fpm (assumption)
Q = 1.4 ' 30 ' 8 ' 240 = 80,000 acfm
2. Dual-side draft hoods
a. Dimensions (p. 5-12, ref. 1)
height = 2 x width of 1/2 of charge
hopper (41) = 8'
width = 4/3 x length of charge hopper (71) = 9'
-------
b. Flowrate reg'd
Q = 200 (10 x2 + hood area)
where 200 is capture velocity which is
assumed to be more like 300 fpm, x =
distance from top of?pot to hood (4') hood
area = 8 x 9 = 72 ft
Q = 300 (160 + 72) = 300 (232) = 70,000 acfm
or for two hoods = 140,000 acfm
3. Single overhead canopy
a. Dimensions: It is assumed canopy can be located at
sight of present (8' x 12' hood). Per p. 4-18,
ref. 1 recommended width is dimension^of charge
chute + .4 D (D = height above source= 16')
nd dimension (E-W) = 7' + 2x (.4) Ib = 20'
ide dimension (N-S) = 8' +0.4(16) = 15'
End
Side
b. Flowrate
Q = 1.4 PDV where P = 30', D = 16', V = 400 fpm
(number assumed)
= 270,000 acfm
Single roof-top collection
a. Dimensions: Use existing roof and close-up
existing louvers
b. Flowrate
Q = 1.4 PDV where P = 30', D = 25', V = 400 fpm
Q = 1.4 (30)(25)400
Q = 420,000 acfm
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PROJECT: Zinc Fuming Furnace, Bunker Hill Lead Smelter
SUBJECT: Preliminary costs for installing a new stack fan
NAME: R. Gosik EPA/NEIC
DATE: 3/29/77
Problem: Determine the installed cost and operating cost for erecting
a new stack fan for the zinc fuming plant.
References: 1. Telephone quotation L. Kreeger, American-Standard, 1/17/77
2. Correspondence R. W. Crosser, Bunker Hill Co., to
R. J. Gosik, USEPA-NEIC, Oct. 6, 1976.
3. Plant Design and Economics for Chemical Engineers, 2nd
Ed., Peters and Timmerhaus, 1968.
Assumptions:
1. Stack fan would be located between cooling tower and baghouse
2. Stack fan should provide 180,000 acfm at 5 in W.G.
3. Other assumptions as noted.
4. Loss in production for down-time not included.
Calculations: 1
Equipment cost
per ref. 1 Fan Cost = $45,000
Motor cost = $7,000
Assume additional ductwork is approximately $2,000
Installation cost
per ref. 1 Normal fan and motor estimated at $8,000
Assume that added cost will be required to cut into
existing balloon flue - 2 men with some crane assistance,
$50 per hour for 1 week. $50 40 hr *
• X - 4>£
3. Maintenance cost: Estimate cost (within $500) as $1,000
per year considering continuous usage in a dusty
environment.
4. Replacement parts: Estimate cost as $500 per year
considering continuous usage in a dusty environment.
5. Electricity: (assume 50% overall efficiency)
Power required
= 1.573 x 10"4
1
180,000 ft3
mm
5 in W.G.
1
1
.5
leff)
= 283 hp
-------
Cost 0 .008$
kwh
= 283 hp
1
7200 kwh
hp/yr
.7 (op. fact.)
1
.008$
kwh
= $11,500
6. Depreciation (10% of installed cost)
0.10 x $64,000 = $6,500
7. Taxes and Insurance (3% of installed cost)
0.03 x $64,000 = $2,000
8. Plant overhead (50% of labor and maintenance)
0.5 x $1,000 = $500
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PROJECT: Zinc Fuming Furnace, Bunker Hill Lead Smelter
SUBJECT: Preliminary costs for adding a new ZnO baghouse section
NAME: R. Gosik EPA/NEIC
DATE: 3/29/77
Problem: Determine the installed cost and operating cost for erecting a
new zinc oxide baghouse section
References: 1. Plant Design and Economics for Chemical Engineers, 2nd Ed.,
Peters and Timmerhaus, 1968.
2. Handbook of Fabric Filter Technology, Dec. 1970,
Vol. I and II, C. E. Billings et al
3. Chemical Engineering, Mar. 14, 1977. Economic Indicators
4. Air Pollution Control Technology and Costs: Seven
Selected Emission Source, IGC1, Dec. 1974
Assumptions: 1,
2,
3,
4,
1 baghouse section identical to those ZnO sections
currently being installed.
The baghouse will handle about 30,000 acfm
Loss in production for down-time not included
Other assumptions as noted.
Calculations: 1. Equipment cost
a. Baghouse proper (per ref. 2 assume $5/acfm cost
of entire system - 1970, the baghouse proper
is 1/3 of that cost)
30,000 acfm
1
3
460 (escalation from 1970)
303
$5 *
acfm
$80,000
b. Auxiliaries
Ducting
Part.Disposal
Instrumentation
°f
(est. from ref. 2)
TOTAL
therefore,
15%
10%
5%
30%
,000 x 0.3 = $25,000
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As a part of installation it will also be necessary to remove
part of the old ZnO baghouse building and foundation and
extend the building. Although this cannot be analyzed
accurately without a detail study, it is estimated as part
of this preliminary study (from ref. 1) that these costs will
be about 25% of the total installed equipment cost:
$105,000 xO.25 = $30,000
2. Operating labor - no additional labor
3. Maintenance (from ref. 2 and 4, it is assumed that
total maintenance costs are $0.5/acfm-yr
at 80% op. factor)
30,000 acfm x$0.5 x0.7_ $15,000
acfm 0.8
yr.
4. Electrical: There will be no change in electrical costs
5. Indirect costs
Depreciation 0.10 x $195,000 = 19,500
Taxes & Insurance 0.03 x $195,000 = 6,000
Plant Overhead 0.5 x $15,000 = 7,500
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PROJECT: Zinc Fuming Furnace, Bunker Hill Lead Smelter
SUBJECT: Preliminary costs for erecting a new baghouse for charging
emissions
NAME; R. Gosik EPA/NEIC
DATE: 3/30/77
Problem: Determine the installed cost and operating cost for erecting
a new baghouse to handle the fuming furnace charging emissions
References: 1
Plant Design and Economics for Chemical Engineers,
2nd Ed., Peters and Timmerhaus, 1968.
2. Handbook of Fabric Filter Technology, Dec. 1970, Vol.
I and II, C. E. Billings, et al
3. Chemical Engineering, Mar. 14, 1977, Economic Indicators
4. Air Pollution Control Technology and Costs: Seven
Selected Emission Sources, IGC1, Dec. 1974
5. Telephone conversation, H. Hoons, Flex Kleen, 1/11/77
Assumptions:
Baghouse can be located nearby to fuming furnace
Baghouse will handle 80,000 acfm gas and operate at
99+% particulate removal efficiency
Loss in production for down time not included in costs
This system assumed to have a 30% annual operating factor
Calculations; 1. Equipment cost
a. Baghouse proper (per ref. 2 and 5, assume collector
for this application at $2.5/acfm based on new
installation)
$2.5
acfm
80,000 acfm _ $200,000
b. Auxiliaries (includes ducting, dust removal,
ventilation fan, hoods and
instrumentation, assume at $.65/acfm
per same refs)
acfm
so.ooo acfm * $50j000
-------
c. Installation (assume installation nearby to
the zinc furnace at $1.5/acfm)
$1-50 x 80,000 acfm * $120,000
acfm
2. Operating labor (from ref. 2)
Assume 1/6 manyear for operator @ $5/hr
1/6 x $200 x 52 wk = $2,000
wk yr
Assume additional 20% for supervisor = $500
Benefits @ 25% of labor = $500
3. Maintenance, labor and replacement parts
(Assume 4 yr service life-acrylic bags, in this duty)
Estimate from refs 2 and 4 approximately $.50/acf-yr
at 80% annual operating factor (incl. operating labor)
80,000 acfm
1
.50 0.3. _
x 0.8 "
acfm
Subtracting out operating labor
$15,000 - $2,500 = $12,500
4. Electricity (assume 8 in. W.G. AP @ 80,000 acfm)
Assume that this is essentially needed
for fan, other electricity req'ts
neglected. Fan overall efficiency is 50%.
8 in. W.G.
1
80,000 acfm
1
1.573 x ID'4 hp
in. W.G. -acfm
1
U.b
eff.)
7200 kwh
hp yr
0.3
(op. fact.)
1
$0.008
kwh
= $3,500
Indirect costs
depreciation
taxes and insurance
plant overhead
= 0.1 x $370,000 = 37,000
= 0.03 x 370,000 = 11,000
= 0.5 x 15,000 = 7,500
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PROJECT: Zinc Fuming Furnace, Bunker Hill Lead Smelter
SUBJECT: Preliminary costs for returning charging fumes to an expanded
ZnO baghouse
NAME: R. Gosik EPA/NEIC
DATE: 3/31/77
Problem: Determine the installed cost and operating cost involved in treating
slag fuming charge fumes in an expanded ZnO baghouse
References: 1. Calculations and references noted in "Preliminary Costs
for Adding a New ZnO Baghouse" Section
2. Calculations and references noted, in "Preliminary Costs
for Adding a New Stack Fan"
Assumptions: 1.
2.
3.
4.
5.
Calculations: 1
One additional ZnO baghouse section will handle the
ZnO charging emissions
An additional stack fan will be necessary
Loss in production from down time not included in costs
Assume 70% annual operating factor
Other assumptions as noted
Equipment cost
a. Baghouse proper (per ref. 1) - $80,000
b. Auxiliaries
Baghouse auxiliaries $25,000 (ref. 1)
Fan auxiliaries $54,000 (ref. 2)
In addition to the above auxiliaries there will
be the cost of installing hoods, a ventilation fan
and ductwork. These are estimated as follows:
hoods $6,000
fan $25,000
ductwork $4.000
TOTAL ^$120,000
c. Installation
Baghouse & auxiliaries 100,000
Hoods, fan, ducting 20,000
$120,000
-------
Operating labor
Assume additional operating labor is negligible
Maintenance - labor, materials and replacement parts
Baghouse
Stack
Ventilating fan
4. Electricity:
Stack fan
Baghouse and
vent fan
15,000
1,500
500
17,000
$11,500
$ 4,500
TOTAL $16,000
Indirect costs
depreciation
taxes and insurance
plant overhead
Ref. 1
Ref. 2
(est.)
Ref. 1
(Ref.: calculations
and references noted in
"Preliminary costs for
erecting a new baghouse
for charging emissions"
+ 2 in. W.G. for added
ductwork)
= 0.1 x $320,000 = 32,000
=0.03 x $320,000 = 9,500
= 0.5 x $ 17,500 = 8,000
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PROJECT: Zinc Fuming Furnace, Bunker Hill Lead Smelter
SUBJECT: Preliminary costs for treating charging emissions in
modified main baghouse
NAME; R. Gosik
DATE: 3/31/77
EPA/NEIC
Problem: Determine the installed cost and operating cost involved in
treating the slag fuming furnace charging emission
References:
1.
2.
3.
4.
Assumptions: 1
2.
3.
Smelter yard map drawing, W10-4, Bunker Hill Lead
Smelter, dated 7/15/57
Plant Design and Economics for Chemical Engineers, 2nd
Ed., Peters and Timmerhaus, 1968.
Chemical Engineering, Mar. 14, 1977, Economic Indicators
Calculations and references noted in "Preliminary costs for
returning charging fumes to an expanded ZnO baghouses"
Calculations and references noted in "Preliminary costs
for erecting a new baghouse for charging emissions"
The modified main baghouse will not require further
modifications to treat zinc fuming furnace charging
emissions
Approximately 300' of 2'<|> ductwork is required
Other assumptions as noted
Calculations: 1. Equipment cost
Hoods
Fan
Ducting
TOTAL
6,000
25,000
6.000
$37,000
Installation = 22,000 (per ref. 4)
2. Operating labor costs are assumed to be negligible
3. Maintenance - labor, materials and replacement parts
$500 (per ref. 4)
4. Electricity:
Assume the electricity cost will be the
same as calculated in ref. 5 with the
addition of approximately another 2 in.
W.G. AP requirements for increased ductwork
through which gas will be transported
3,500 x 1.25
Indirect costs
Depreciation
Taxes and insurance
Plant overhead
= $4,500
= 0.1 x 59,000
= 0.03 x 59,000
= 0.5 x 500
= $6,000
= $2,000
= $ 500
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