United States
Environmental Protection
Agency
Industrial Environmental Research s
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-84-026 Mar. 1984
SERA Project Summary
Inspection and Operating and
Maintenance Guidelines for
Secondary Lead Smelter Air
Pollution Control
Fred Hall, Ron Hawks, Gary Saunders, and John 0. Burckle
Secondary lead smelters are an
important segment of the domestic
nonferrous metals industry- Over the
last five years they accounted for 55 to
58 percent of the total domestically
supplied lead. In 1982, about 95
percent of the secondary lead was
produced by 48 major operating plants
with the balance supplied by a large
number of very small plants.
The toxicity of lead together with its
relatively high vapor pressure at operating
furnace temperatures make it a serious
environmental/occupational health
problem that is difficult to control
economically. The U.S. Environmental
Protection Agency (EPA) has promul-
gated a National Ambient Air Quality
Standard (NAAQS) for lead of 1.5/ug/m*.
The Occupational Safety and Health
Administration (OSHA) has promul-
gated a workplace standard of 50
/ug/m3 and a blood level standard of 40
/ug/100 ml of whole blood. Operation
and maintenance (O&M) techniques
will become important tools in main-
taining continued compliance with
these standards.
This Project Summary was developed
by EPA's Industrial Environmental
Research Laboratory. Cincinnati, OH.
to announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
The success of an air pollution compli-
ance program ultimately depends upon
the competence of the field inspectors
and the adequacy of their inspections.
The ability to identify, describe, and
evaluate air pollution emissions and
those factors responsible for their
occurrence is a fundamental requirement
of the inspection process. Both the
availability of sound inspection procedures
and adherence to the procedures are of
vital importance to the inspection process.
An air pollution control agency having
adequate enforcement powers but inade-
quate inspection procedures would be
unlikely to make significant progress
towards attainment of air quality goals.
Also, such an agency may even see
erosion of its enforcement powers as a
result of adverse court decisions arising
from improperly executed inspections.
The most important aspect of mainte-
nance of air quality is the attainment of
"continuing compliance." A "continuing
compliance inspection" is an inspection
of sources, which have previously proved
initial compliance with the regulations in
that they have installed the necessary air
pollution control equipment and/or
modified their process(es) to be able to
meet required emission limits, to deter-
mine that they remain in compliance on a
continuing, long-term basis. Most agen-
cies perform a continuing compliance
inspection once or twice a year depend-
ing upon their resources or any complaints
received.
Report Summary
The manual was developed as an
inspection manual incorporating opera-
tion and maintenance information for
-------
secondary lead smelting. It presents an
overview of secondary lead operations,
describes typical emission problems
associated with the material preparation,
smelting, refining, and oxidation process-
es (Figure 1), and reviews the potential
causes of the problems and possible
corrective measures. It also describes
types of control equipment used in
secondary lead smelting operations and
typical O&M problems experienced with
control equipment. Topics include: (1)
process description and flow diagrams for
a typical secondary lead smelter and lead
oxide process; (2) operating conditions
typical of secondary lead smelting
operations; (3) process and fugitive
emissions operations and their control;
(4) design considerations to improve
O&M; and (5) basic operation and
maintenance procedures necessary to
remain in compliance, including typical
O&M problems associated with the
secondary lead industry, such as corro-
sion, proper instrumentation required for
reliable operation, proper recordkeeping
procedures, waste handling guidelines,
and safety considerations.
The prevention of lead emissions from
secondary smelters is shown to depend
largely on O&M practices. Fabric filters
are usually used to remove paniculate
matter from lead smelter process and
ventilation gas streams. Because proper-
ly operated fabric filters are very efficient,
little lead particulate matter is emitted in
stack gases when operated under condi-
tions of continuing compliance. Fugitive
emissions, however, are a major prob-
lem. Control systems are only partially
effective in capturing fugitive emissions.
Also, handling of the lead particulate
matter after it has been collected is a
potential cause of fugitive emissions.
Lead dust escapes from the material
handling and smelting processes into the
workplace and is continually reentrained
and dispersed throughout the smelter.
Emission factors for specific sources are
given in Table 1. Sufficient reentrainment
may occur to cause the NAAQS of 1.5
//g/m3 to be exceeded. Continued compli-
ance can be achieved only by applying the
appropriate combination of engineering
and administrative controls, and by
adopting operating, maintenance, and
housekeeping practices to make those
controls work effectively.
The manual is heavily oriented toward
an inspection approach emphasizing tech-
niques to achieve improvements in the
status of continuing compliance through
operations and maintenance procedures.
It has been written for use both as an
educational and a reference tool by state
and local enforcement field inspectors
and entry-level engineers whose famil-
iarity with secondary lead operations may
be limited, and, as such, can be useful
both as a training manual and as a guide-
book during field inspections.
Inspection of a secondary lead smelter
requires that data be recorded on site for
later use in evaluating smelter emission
control and compliance practices. The
following items are useful to ensure that
the inspection is complete and to maximize
the pertinent information that can be
Pretreatment
n nn
Refining
Products
Draining and
Decasing
Sloping Hearth
Dross
and — *|
Fine Dust [
,--H Dust f 1
I Agglomeration \
_j niwi
e, !
\> Solid
Residues
I— »JZinc, ty% -
I Leaching \ v
Figure 1. Sources of air emissions from secondary lead plants.
2
-------
Table 1. Sources and Emission Factors for Point and Fugitive Emissions from Secondary Lead Smelters"
Point source emissions. Ib/ton
Fugitive emissions, Ib/ton
Source
Raw material handling and transfer
(scrap lead, scrap iron, coke,
limestone, etc.)
Lead and iron scrap burning
Battery decasing
Crushing or shredding
Rotary or reverberatory furnace
Paniculate
NA
NA
NA
NA
32-70
Lead Basic*
NA
NA
NA
NA
7-16 £
Paniculate
NA
NA
NA
NA
Lead Basicc
NA
NA
NA
NA
sweating
Charging
Tapping
Scrap removal
Reverberatory furnace smelting
Charging
Slag tapping
Lead tapping/casting
Blast furnace smelting
Charging
Slag tapping
lead tapping/casting
Holding pot
Reverberatory furnace softening
Charging
Tapping (drossing, skimming,
lead removal)
Kettle softening/refining
Charging
Tapping fdrossing, skimming,
lead removal!
Kettle alloying/refining
Charging
Tapping, drossing, skimming
Kettle oxidation"
Charging
Reverberatory furnace oxidation
Charging
147
193
NA
NA
34
44
NA
NA
B
0.8
<40
NA
0.2
NA
NA
1.6-3.5
2.8-15.7
NA
NA
0.04
NA
NA
NA - data not available.
"Source: U.S. Environmental Protection Agency. Compilation of Air Pollution Emission Factors. 1980.
b All emission factors are based on the quantity of material charged to the furnace (except paniculate kettle oxidation).
0 The basis of the emission factor refers to the method from which the emission factor was obtained.
B - Emission factor based on source test data and is rated (EPA 1980) as above average.
E - Engineering estimate supportable by visual observation and emission tests for similar sources.
These emission factors are rated (EPA 1980) poor.
" Factors based on amount of lead oxide produced.
' Factors based on amount of lead cast.
0.4-1.8
0.6-3.6
NA
NA
0.01
NA
NA
Casting (pigging f
Flue dust handling and transfer
Vehicular traffic
Traffic on paved roads
Traffic on unpaved roads
Hooding, ductwork, control
device, or furnace leaks
NA
NA
NA
NA
NA
NA
NA
NA
0.88
NA
NA
NA
0.2
NA
NA
NA
E
-------
obtained while the inspector is on site:
• Smelter plot plan
• Engineering drawings or sketches
of equipment and specifications
• Process flowsheet and equipment
checklist
• Raw material/product checklist
• Individual process worksheets
• Emission control equipment (systems)
acceptance or performance test
results
• Maintenance records
Most of these items can be obtained
during the file review at the appropriate
EPA Regional and local offices, especially
results of performance tests conducted to
determine compliance.
Prior to the inspection, the worksheets,
process flows, and maintenance records
should be reviewed with the plant's
representative at the plant. Organizing
these items prior to the actual inspection
helps ensure that all necessary data are
obtained.
The purpose of inspecting control
equipment is to evaluate system perform-
ance with respect to regulatory require-
ments and operation and maintenance
procedures. Inspections can vary in
detail, depending upon the objective. For
example, cursory inspections can be
performed by only quick, external exami-
nation of the control equipment and
recording of several temperature and
static pressure readings. Thorough
inspection requires more detailed analy-
sis of the control system and perhaps an
internal inspection of the equipment.
Inspection requirements should be
tailored to the characteristics of each
facility, and the time available for each
inspection.
An inspector, upon arrival at the plant
to be inspected, should determine exist-
ing plant self monitoring procedures by
questioning plant management. Any
records that show control system operat-
ing parameters and production levels
should be quickly reviewed to estimate
plant "baseline values". A baseline value
is the value of a given parameter (e.g., fan
static pressure and temperature or fabric
filter pressure drop) when all the equip-
ment in a system is operated in a manner
that provides acceptable performance. If
actual operating values differ significant-
ly from baseline values, operation of the
process or control equipment has changed
enough to warrant further questioning of
plant personnel to determine probable
reasons for these deviations.
Some parameters can indicate the
performance of the control equipment.
These include opacity and fan parameters.
Opacity
Observation of the opacity and compar-
ison of this value with the baseline value
provides the initial indicator of any
process or control equipment perform-
ance variation.
Fan Parameters
Fan parameters are generally the
parameters that plant and regulatory
personnel use the least in evaluating
control equipment performance. Each fan
has a unique static pressure/motor
current/gas volume curve at any given
speed. Because fan speed is usually fixed
(and must be manually and intentionally
changed by plant personnel), it need not
be measured each time plant personnel
check the system. The gas volume
through the fan may be read directly
from the curve.
Fabric Filters
The most frequently used indicator for
fabric filter operation is the pressure
drop across the filter medium. The
cleaning system operation should be con-
firmed, and the timing sequence should be
recorded. The waste handling system
(including hoppers, airlocks, and convey-
yors) should be checked for proper
operation. Hoppers should not be used for
storage of captured dust. Although
hoppers may be insulated, the hopper
discharge should be warm to the touch. A
cold hopper discharge on a "hot source"
may indicate hopper plugging.
The previous steps provide some
information, but the only reliable method
of evaluating fabric filter performance is
internal inspection. Safety is a prime
concern in performing an internal inspec-
tion. Generally, special equipment is
required to enter these baghouses.
The actual internal inspection takes
little time. The majority of the time
required is used to prepare equipment and
to isolate and open compartments. The
location and nature of all bag failures
should be recorded for maintenance
schedule optimization. The use of a
fluorescent dye and a portable UV light
may be helpful in identifying problems.
Pinholes and bag seal leaks are easily
spotted. Figure 2 indicates the steps for
internal and external inspections of fabric
filters.
Wet Scrubbers
Inspection of a wet scrubber relies
heavily on baseline values because
internal inspection of the equipment is
not usually possible. An inspector must
attempt to quantify any change in
efficiency based upon a change in the |
water flow rate, pressure drop, gas 1
volume (throat velocity), or gas tempera-
ture. The only other parameter that can
significantly affect scrubber performance
is a shift in the particle size distribution.
Such a shift is difficult to measure, but
generally decreases collection efficiency,
when the shift is to smaller sizes, when
all other parameters are held constant.
Because of the low gas stream temper-
ature, other problems with liquor solids
content and evaporation are not typically
encountered. Corrosion is generally
limited because of construction practices
(e.g., the use of 316 stainless steel). Little
day-to-day variation in scrubber operation
is expected.
For inspection purposes, the ventilation
system is def i ned as the ductwork leadi ng
from the emission points to the control
devices. Two major problems with venti-
lation systems are duct plugging and
excessive air inleakage, both of which
cause changes in the static pressure and
temperature profiles of the ductwork
system. An inspector should carefully
examine the ventilation system to identify
the problem. Static pressure taps are
recommended throughout the length of
ductwork to provide data on air inleakage
and ductwork plugging. A
The ventilation system inspection ™
should include routine measurement of
the temperature and static pressure at
the furnace or kettle hood outlet, at the
afterburner outlet (if applicable), at the
inlet and outlet of the cooling loops, and
at some point downstream of dilution air
dampers. These parameters vary with
production rate, and ambient temperature
and operating logs should be examined to
determine long-term baseline values,
which take into account normal process
variations.
In addition to the measurement of
static pressure and temperature at the
emission point, the face velocity and
positioning of all fugitive hooding should
be checked. Improper positioning of
hooding or hood damage may result in the
reduction of capture efficiencies. Low
duct static pressures indicate an undersized
or underperforming fan.
-------
External Inspection
Internal Inspection
Check Pressure Drop Across
Each Compartment,
I
Check Condition of Lines
and Pressure Gauges.
I
Check Cleaning System
Equipment:
Pulse-Jet Mechanism
Solenoids
Reverse-Air Blowers
Shakers
I
Check Solids Removal
Equipment-
Screw Conveyor
Pneumatic System
Heaters
Vibrators
1
Investigate any Other
Indications of Nonoptimal
Performance.
Check Bags:
Bag Tears
Bag Deterioration
Dropped Bags
Oily Bags
Wet Bags
Improper Bag Tension
Deposits on Floor
±
Check Clean Air Chamber
for Possible Leaks.
±
Check Hoppers for
Incomplete Solids Removal
and for Corrosion.
Figure 2. Steps for external and internal inspection of fabric filters.
Fred Hall. Ron Hawks, and Gary Sounders, authors of the Project Report are with
PEDCO Environmental. Inc., Cincinnati. OH 45246; John BurcUe, author of the
Project Summary and EPA Project Officer (see below}, is with the Industrial
Environmental Research Laboratory, Cincinnati, OH 45268.
The complete report, entitled "Inspection and Operating and Maintenance
Guidelines for Secondary Lead Smelter Air Pollution Control," (Order No. PB
84-149 368; Cost: $14.50, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
U. S. GOVERNMENT PRINTING OFFICE: 1984/759-102/0897
-------
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
"34
Official Business
Penalty for Private Use $300
j: i •
------- |