AIR POLLUTION CONTROL TECHNOLOGY APPLICABLE
TO 26 SOURCES OF VOLATILE ORGANIC
COMPOUNDS
Prepared By
Emission Standards and Engineering Division
Office of Air Quality Planning and Standards
May 27, 1977
U. S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
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AIR POLLUTION CONTROL TECHNOLOGY APPLICABLE
TO 26 SOURCES OF VOLATILE ORGANIC
COMPOUNDS
Prepared By
Emission Standards and Engineering Division
Office of Air Quality Planning and Standards
May 27, 1977
U. S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
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INTRODUCTION
In recent months, OAQPS has redirected much of its effort to the
review of control technology for principal sources of volatile organic
compounds (VOC). The output of these studies will be control technology
guidelines (CTG) documents and, where appropriate, new source performance
standards. CTG documents identify the effectiveness of alternative
control technologies as well as costs, applicability, and energy and
environmental considerations. CTG documents are now available in draft
or final form for degreasing, dry cleaning, gasoline bulk terminals,
five specific surface coating operations, and miscellaneous petroleum
refinery sources.
Since much of the requisite control technology and related information
is available for several other VOC sources, it was deemed desirable to
prepare statements which highlight air pollution control aspects for the
26 VOC sources cited herein. The statements briefly describe technologies
which are applicable and cite costs, energy and environmental impacts,
and factors which may limit applicability of the technologies along
with principal references. It is OAQPS intention to finalize CTG
documents for these VOC sources over the next 12 months.
The VOC sources for which control technology summaries are presented
cover a broad spectrum of industry ranging from petroleum refining
through gasoline marketing, surface coating, and solvent-use industries.
Current emissions from the 26 sources are estimated to be approximately
6,500,000 metric tons per year. This total represents 23 percent of
all VOC sources and 37 percent of stationary sources.
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A number of major VOC sources (representing an additional 38 percent
of the stationary source emissions) are under study but are not included
in this summary. Five specific surface coating industries (automobile
assembly, can, coil, paper, and fabric coating) and the dry cleaning
industry were not summarized since CTG documents will be available in the
very near term. Chemical manufacturing operations are also not included
since OAQPS has just initiated a major contract effort in this area which
will not yield initial results until mid-1978. Work has also been
initiated to assess VOC emissions from ship and barge transfer operations.
Stage II (vehicle fueling) service station controls are not included
because comments on the November 1, 1976, proposal are under review.
The remaining 25 percent of the VOC emissions from stationary sources are
emitted from combustion sources, other manufacturing processes, and
small solvent users. Should you be aware of major VOC sources which
d
have not been scheduled for review, please bring them to the attention
of Mr. Robert T. Walsh, Chief, Chemical and Petroleum Branch, Emission
Standards and Engineering Division, MD-13, U. S. Environmental Protection
Agency, Research Triangle Park, North Carolina 27711.
ii
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TABLE OF CONTENTS
Page Number
Storage of Crude Oil and Gasoline . .... 1
Tank Truck Gasoline Loading Terminals 5
Bulk Gasoline Plants 8
Gasoline Service Station Underground Tank Loading .......... 11
GasolineJTank Trucks in Transit . 14
Petroleum Refineries
Leaks from Miscellaneous Refinery Sources • "• • • 16
Refinery Process Drains and Wastewater Separators . . . . .. . . 19
Refinery Vacuum Producing Systems .... 22
Refinery Process Unit Turnaround • ..........24
Leaks from Natural Gas and Natural Gasoline Processing 26
Plants .
Leaks from Oil and Gas Production Fields 29
Cutback Asphalt Paving .31
Cold Cleaning with Organic Solvents . . 34
Vapor Degreasing . 38
Graphic Arts
Rotogravure Printing Operations ... 43
Web-Offset Printing Operations 4.5
Web Letterpress Printing Operations 48
Flexographic Printing Operations 52
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Page Number
Rubber Tire Industry
Camel back or Tread End Manufacture 55
Fabric and Wire Dip and Cement 57
Green Tire Spraying 60
Adhesives ....... 62
Large Appliances 64
Magnet Wire Coating 67
Flat Wood Products 70
Industrial Surface Coating ............ 73
iv
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STORAGE OF CRUDE OIL AND GASOLINE
Process Description
The floating roof tank is most commonly used for storage of gasoline
and crude oil. The tank consists of a welded or riveted cylindrical
vessel equipped with a deck or roof which floats on the liquid surface
and rises and falls according to the liquid level in the tank. The liquid
surface is completely covered by the roof except for the space between the
roof and the wall. A sliding seal(s) attached to the roof contacts the
tank wall and covers this space. Escape through this seal is the primary
source of hydrocarbon emissions.
Base Line Emissions
Base line (current control) hydrocarbon emissions nationwide from
gasoline and crude oil storage tanks calculated from correlations in API
1 7
Bulletin 2517 are 1,540,000 metric tons per year. ' This represents 8.9
percent of the estimated 1975 national emissions from stationary sources.
Approximately 60 percent or 926,000 metric tons per year are from floating
roof tanks. The new source performance standard promulgated March 8, 1974,
and many State and local regulations require floating roofs for storage of
gasolines and crude oils after the point of crude oil custody transfer.
The remaining 614,000 metric tons per year .emissions are primarily from the
storage of crude oil and gasoline in fixed roof tanks where floating roof
tank control is not required.
Control Technology
A floating roof tank with a single (primary) sliding seal, either a
metallic-shoe-type seal or nonmetallie-resilient-type seal, is the most commo.
used control technology. While this technology has the potential for
1
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reducing emissions by 70-90 percent compared to storage in a fixed roof
tank, nevertheless there are still substantial emissions largely through
the seal system. Seal losses increase if there is an improper fit
between the single seal and wall which creates gaps through which vapors
are released, leakage through the fabric cover that is used to bridge
the space between the shoe seal and the floating roof, or gaps caused by
rivet heads in the older riveted tanks.
While good maintenance and inspection .programs may be effective in
reducing emissions through the single seal, recent industry tests have
indicated that significant reductions can be achieved by using double
seal technology. This consists of installing a second seal (secondary)
over the single shoe or resilient type seal (primary). Limited test
data indicate that losses with tight secondary and tight primary resilient
type seals are 10 to 25 percent of the loss with a tight primary only.,
Double seal technology will not eliminate the need for frequent maintenance
and inspection programs.
Cost of Control
Since most gasoline and crude oil storage tanks already are equipped
with single seals, the cost of control will be limited to the additional
cost for installing a secondary seal on new tanks or the cost of retro-
fitting existing tanks. Retrofit will be more costly.
Secondary seals cost about $16 per linear foot installed for retrofit
applications. For a tank 200 feet in diameter and 44 feet high with a
capacity of 250,000 barrels the capital cost to retrofit a secondary seal
is $9,800 and the annualized cost $3,000 per year excluding value of the
recovered product. The total capital cost of a floating roof tank with a
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primary seal installed at an East Coast location is $9.80 per barrel
or $2,450,000. Emission reduction and hence cost effectiveness of secondary
seals over and above primary seals will vary with the wind velocity and the
true vapor pressure of the stored product. This is illustrated in the
table below.
Hydrocarbon emission
reduction, metric tons/yr
Value3of hydrocarbon
saved
Annual cost to retrofit
minus saving
Cost of emissions
controlled, $/metric ton
4 MPH
3.0 psia
3.6
$400
$2,600
$722
1
6.0 psia
7.2
$800
$2,200
$305
8 MPH
3.0 psia 6.0 psia
10.9 21.8
$1,200 $2,300
$1 ,800 $700
$165 $ 32
Wind velocity, miles per hour.
2
Vapor pressure of stored liquid product, pounds per square inch absolute.
3
Value of recovered hydrocarbons is assumed to be $110 per metric ton.
References
1. American Petroleum Institute Bulletin 2517, "Evaporation Loss
from Floating Roof Tanks," February, 1962.
2. "Control of Hydrocarbon Emissions from Petroleum Liquids,"
EPA-600/2-75-042, September, 1975.
3. "Control of Volatile Organic Emissions from Existing Stationary
Sources - Volume I: Control Methods for Surface-Coating Operations,"
EPA-450/2-76-028, November, 1976.
4. "SOHIO/CBI Floating Roof Emissions Program, Interim Report,"
October 7, 1976; "SOHIO/CBIFloating Roof Emissions Program, Final
Report," November 18, 1976.
3
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5. Personal Communication with Manufacturers and Fabricators, May,.
1977.
6. "Petroleum Storage Capacity for National Security," draft report,
National Petroleum Council, August 6, 1975.
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TANK TRUCK GASOLINE LOADING TERMINALS
Process Description
Motor gasoline produced at petroleum refineries is transferred primarily
by pipeline, ship or barge to intermediate storage at loading terminals.
Various grades of gasoline are dispensed through loading facilities into
tank trucks. From terminals the gasoline is delivered to bulk plants or
to commercial or retail accounts (service stations). It is estimated that.
there are approximately 2000 tank truck gasoline loading terminals in the
United States. At uncontrolled terminals the truck compartments are
vented to the atmosphere during loading operations.
Base Line Emissions
Base line (uncontrolled) emissions of hydrocarbon nationwide from
tank truck gasoline loading terminal operations are estimated to be
300,000 metric tons per year, assuming an emission factor of 1 kilogram
per liter (kg/1) and a national throughput of 1065 million liters per
day (1/d).1 This represents 1.8 percent of the estimated 1975 national
2
hydrocarbon emissions from stationary sources. Based on sparse data,
it is estimated that 25 percent of 2000 tank truck gasoline loading
terminals are controlled to some degree.
Control Techno!ogy
Control technology utilized to minimize emissions during tank truck
gasoline loading include: 1) top-submerged or bottom loading of gasoline
(58 percent efficient); 2) vapor recovery equipment (93+ percent efficient);
and 3) thermal oxidation (99+ percent efficient). A well designed vapor
recovery system will reduce the hydrocarbon concentration of exhaust gases
to less than 5 percent by volume. In a thermal oxidizer system if a firebox
temperature of 760°C or greater is maintained, a 99+ percent efficiency for
the unit would be anticipated.
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When vapor recovery or incineration are used, precautions should
be taken to ensure that there are no leaks from the trucks and vapor
collection equipment during loading. Leaks can be monitored with portable
hydrocarbon detectors. Hatches and pressure relief valves on trucks and all
valves and connections leading to the vapor control device should be
monitored. An emission level of 80 milligrams per liter (mg/1) of
gasoline loaded can be achieved with a vapor recovery system and
27 mg/1 with an oxidation system provided good leak prevention is
maintained. Emission levels with bottom fill or top-submerged fill
will be approximately 610 mg/1. Approximately 300 terminals have
been equipped with vapor control equipment; most have retrofitted
vapor recovery systems to existing facilities. It is estimated that
10 facilities are equipped with thermal oxidizers.
Energy Requirements
The energy requirements for top-submerged or bottom fill are minimal.
When vapor recovery is used, the energy required to operate the recovery
system is more than offset by the increased gasoline recovery. Thermal
oxidizers have about the same energy requirements as vapor recovery
systems, but there is no offsetting credit for product recovery. Terminals
rarely can utilize waste heat from incinerators.
Cost of Control
Estimated capital costs to retrofit an existing top-splash fill,
950,000 1/d terminal, are estimated to be $1500 where simple drop tubes
are installed at two racks (with 3 loading arms per rack); $194,000
for converting the two loading racks and the trucks from top-splash
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loading to bottom loading; plus an additional $141,000 for thermal
oxidizers or $205,000 where vapor recovery is installed. Estimated
annual direct operating costs are negligible for drop tubes or bottom
loading. Estimated annual direct operating costs range from $5,500
per year for thermal oxidizers to $8,000 per year for vapor recovery
systems. For a 950,000 1/d terminal with vapor recovery with 100
percent recovery of vapors from the tank truck, an estimated annual
credit of $48,700 for recovered gasoline would be realized. The
estimated cost effectiveness of a 950,000 1/d terminal converted to
bottom-fill loading with refrigeration type vapor recovery approximates
$0.18 kilogram of hydrocarbon controlled.
References
1. "Control of Hydrocarbon Emissions from Petroleum Liquids,"
EPA-600/2-75-042, September 1975.
2. "Control of Volatile Organic Emissions from Existing Stationary
Sources - Volume I: Control Methods for Surface Coating Operations,"
EPA-450/2-76-028, November 1976.
3. "Control of Hydrocarbon from Tank Truck Gasoline Loading
Terminals," EPA guideline document in preparation to be released
in 1977.
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BULK GASOLINE PLANTS
process Description
Bulk gasoline plants are typically secondary distribution facilities
which receive gasoline by large tank trucks, and subsequently distribute
it via small tank trucks to farms, businesses, and service stations. A
typical bulk plant has three fixed roof storage tanks with a total storage
capacity of 185,000 liters and an average daily throughput of 75,700 liters.1
In 1972 there were -approximately 23,000 bulk plants in the U.S.; the number
.declined- by ,11.3 percent from 1967 to 1972.2
Base Line ;Emisston.s
Hydrocarbon vapors are emitted to the atmosphere during filling of
storage tanks and loading of tank trucks. Additionally, breathing losses
occur at storage tanks. The estimated nationwide uncontrolled emission from
bulk plants is ,146,000-metric tons per year (68,000 metric ton's per year
from tank truck loading losses and 78,000 metric tons per year from storage
2
tank breathing and working losses). Emissions from bulk plants contributed
to about 0.8 percent of the total 1975 National hydrocarbon emissions from
4
stationary sources.
Control Technology
Vapor control techniques currently in use at bulk plants include:
top-submerged fill, bottom fill, and vapor balance. Bottom and top-
submerged loading can reduce truck loading emissions by 58 percent, and
can be retrofitted to existing racks and tank trucks. Probably the only
vapor control system currently in use is .the vapor balance system. Tests
on two vapor balance systems indicate that they can achieve 90 to 100 percent
5
efficiencies. Although condensation, adsorption, and incineration systems
are commonly used in controlling gasoline bulk terminal emissions, they
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have not been installed at bulk plants because of their high cos-ts.
No technical impediments prevent their use at bulk plants.
Vapor leakage from tank truck hatch seals, piping connections, and
pressure-relief valves will result in low vapor recovery efficiencies for
balance systems. It is particularly important that the tank truck hatches
be tightly sealed during all transfer operations. The overall effective-
ness of vapor balance systems will depend on efficient recovery or
destruction of the vapor collected in the bulk plant delivery truck at
the bulk terminal. If bulk terminals are not equipped with vapor recovery
or incineration systems there will be some loss in efficiency.
Cost of Control
For an existing 75,700 liters per day top-splash fill bulk gasoline
plant the estimated capital cost of conversion for top-submerged fill is
$640 or $71,800 for bottom fill. The approximate annualized cost for
conversion from top-splash to bottom fill is $8,900 or $270 per metric
ton of hydrocarbon recovered. Conversion from top-splash to top-submerged
fill will result in an annualized.credit of $4,800 or $120 per metric ton
of recovered hydrocarbon.
The capital and annualized costs of installing a vapor balance control
system at an existing 75,700 liters per day plant are $47,100 and $1,410
respectively. The cost-effectiveness of a vapor balance system is $179
per metric ton of HC controlled for plants using top-splash and $470 per
metric ton of HC controlled for plants using bottom or top-submerged fill.
References
1. "Study of Gasoline Vapor Emission Controls at Small Bulk Plants,"
EPA 68-01-3156, October, 1976.
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2. U. S. Department.of Commerce, Bureau of Census, 1972 Census of
Wholesale Trade, subject series, "Petroleum Bulk Stations and Terminals,"
#WL 72-5-2, U. S. Government Printing Office, Washington, D.C.
3. "Control of Hydrocarbon Emissions from Petroleum Liquids,"
EPA-600/2-75-042, September, 1975.
4. "Control of Volatile Organic Emissions from Existing Stationary
Sources - Volume I: Control Methods for Surface-Coating Operations,"
EPA-450/2-76-028, November, 1976.
5. "Control of Volatile Organic Emissions from Bulk Gasoline Plants,"
EPA guideline document in preparation to be released in 1977.
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GASOLINE SERVICE STATIONS
UNDERGROUND TANK LOADING
Process Description
There are two major emission sources in gasoline service stations;
the loading of gasoline into underground storage tanks (Stage I) and the
fueling of vehicles (Stage II). In both cases, gasoline vapor is displaced
from the tanks by the incoming liquid. A lesser source is breathing losses
in storage tanks.
Base Line Emissions
Emissions vary with filling rate, filling method, Reid vapor pressure,
and system temperatures. Based on an estimated loss of 1.1 grams per liter*
(g/1) of gasoline loaded, national emissions from loading underground tanks
at service stations are 400,000 metric tons per year or 2.3 percent of total
stationary source emissions in the United States. An additional 0.1 g/1
of vapor is lost through breathing vents in underground tanks. This adds
42,000 tons per year bringing the total emissions from the storage tanks
to 442,000 tons per year or 2.6 percent of.stationary source emissions.
Control Technology
Stage I losses can be reduced significantly by returning the displaced
vapors from underground storage tanks to the delivery tank truck. The
collected vapors are displaced to a vapor recovery system at the bulk
terminal when the truck tanks are filled. Thus, vapors from service
station storage tanks are ultimately controlled at the terminal. The
"vapor balance system" itself (vapor return hose from service station
*Submerged fill = 0.88 gram per liter, splash fill = 1.4 grams per liter.
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underground storage tanks to tank truck compartments and a submerged
fill pipe to reduce vapor generation) is 93 to 100 percent efficient
in controlling working losses. The effectiveness of the system is
reduced considerably if leaks exist in the vapor collection lines
or in the truck tanks or if the truck hatches are not tightly sealed
while in transit.
Fifteen air quality control regions have implemented this control
strategy (Stage I) in service stations. No devices are used specifically
to control breathing losses, however, where Stage II control systems are
employed (balance underground tanks and vehicle tank) breathing losses
are greatly reduced.
Cost of Control
Stage I capital costs have been estimated at $1900 per station made
up as follows:
Drop tubes, vent valves - $ 300-500
Installation - $ 100
Trenching, backfill
paving - $1,300-1,600
Operating costs are insignificant. For a typical service station
dispensing about 227,000 liters (60,000 gallons) of gasoline per month,
the cost effectiveness of a Stage I is estimated to be a credit of $77
per metric ton of gasoline recovered.
These do not include minor costs associated with conversion of trucks
to balance systems. They do, however, include trenching and backfill
paving costs which could be associated with Stage II controls.
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References
1. "Revision of Evaporative Hydrocarbon Emissions Factors,"
Radian Corporation for EPA-OAQPS, EPA-450/3-76-039, August 1976.
2. "Control of Hydrocarbon Emissions from Petroleum Liquids,"
Radian Corporation for EPA-IERL, EPA-600/2-75-042, September 1975.
3. "A Study of Vapor Control Methods for Gasoline Marketing
Operations," Volume I and II, Radian Corporation for EPA-OAQPS,
EPA-450/3-75-046 a and b, April 1975.
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GASOLINE TANK TRUCKS IN TRANSIT
Process Description
Motor gasoline is loaded into tank trucks for distribution to bulk
plants, commercial accounts, and retail service stations. During transit
on the return trip from the site of the gasoline drop to the terminal,
open or leaking hatches, connections, or pressure-vacuum valves can cause
the loss of hydrocarbon vapors.
Base Line Emissions
Base line (uncontrolled) emissions nationwide from tank truck hatch
covers are estimated to be 45 to 90 metric tons per year. This estimate
is based on a volume of 1065 million liters per day of gasoline transported
in tank trucks; the vapors in the truck being saturated; and a gross
estimate of 10 to 20 percent loss of the vapor during transit. EPA source
tests indicate that a large loss of vapor from tank trucks has occurred
in many instances prior to gasoline loading operations. These losses are
0.25 to 0.5 percent of the estimated 1975 national hydrocarbon emissions
from stationary sources and 4.0 to 8.0 percent of the emissions from
2
transportation sources.
Control Technology
The installation and maintenance of effective hatch seals and pressure-
vacuum vents and ensuring that the hatches are shut and locked prior to
transit is all that is required to virtually eliminate the estimated 45 to
90 metric tons or more of hydrocarbon currently being emitted. There will
still be some emission, however, due to the effect of diurnal temperature
changes on truck compartments causing venting through relief valves to the
atmosphere.
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Cost of Control
The cost of control will be limited to the cost of installing and
maintaining effective seals, connections, and pressure-vacuum valves.
This cost is considered to be minimal compared to the value of the product.
recovered.
References
1. "Control of Hydrocarbon Emissions from Petroleum Liquids,"
EPA-600/2-75-042, September, 1975.
2. "Control of Volatile Organic Emissions from Stationary Sources
Volume I: Control Methods for Surface-Coating Operations," EPA-450/2-76-028,
November, 1976.
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LEAKS FROM MISCELLANEOUS REFINERY SOURCES
Process Description
Petroleum refining is the third largest industry in the United States
and presents a potential hydrocarbon (HC) emission problem by virtue of
the large quantities of petroleum liquid refined and the intricacy of the
refining process. There are 266 refineries currently operating in the
United States. Refineries process crude oil through fractionation,
decomposition, rebuilding and rearrangement, extraction, and product
finishing into over 2500 products.
Base Line Emissions
Miscellaneous sources of HC emissions that are considered here
include: (1) pipeline valves, flanges, and other connections, (2) pump
and compressor seals, (3) pressure relief devices, and (4) sampling
systems.
Based on January 1, 1977, refinery capacity the hydrocarbon
emissions from the refinery sources listed above are estimated to
2
amount to over 160,000 metric tons per year or about one percent of
the stationary source hydrocarbon emissions. These estimates are
based on data obtained by the Los Angeles County Joint Study of
34
petroleum refinery emissions in the late 1950's and EPA studies.
Control Technology
Controls for refinery hydrocarbon emissions fall into two categories,
equipment specifications and monitoring techniques. Proper equipment must
be installed and kept in good working order by a regular leak detection
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and maintenance program. A component is considered to be in good working
order if there is no hydrocarbon concentration above 100 ppm as hexane
at 5 centimeters from the surface.
There should be a daily unit area walkthrough inspection to locate
leaks. When the ambient hydrocarbon concentration anywhere within the ;
unit area is over 20 ppm, there is probably a leak present in the unit.
The component causing the elevated concentration should be located and <
should be repaired if it exceeds the 100 ppm level.
In addition to the daily unit area monitoring, certain components
should be individually checked for leaks and certain components should
have specified control equipment installed. The pipeline valves should
be individually checked for leaks monthly. Rotating pumps and compressors
should be fitted with mechanical seals when possible, and all pumps and
compressors should be checked for leaks daily. Pressure relief valves
should either be vented to the flare header system, protected by a rupture
disc, or inspected monthly. Sampling equipment should be checked daily
for leaks. It is estimated that implementation of this program would
reduce hydrocarbon emissions from these sources by 91 percent to 14,000
2
metric tons per year.
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Cost of Control
Since the control equipment discussed above is presently being
operated in several refineries, it appears the controls are justifiable
either in terms of cost-benefit for recovered product or safety. It
is also felt that the cost of the additional instrumentation and personnel
needed to implement the leak detection and maintenance plan will be
appreciably offset by savings from product recovery. Therefore, no
rigorous cost-benefit analysis has been developed since the cost impact
will be minimal.
References
1. "Annual Refining Survey," The Oil and Gas Journal, March 28,
1977.
2. "Control of Hydrocarbon Emissions from Miscellaneous Refinery
•» ••» •••••..
Sources," EPA guideline document in preparation to be released in 1977.
3. "Joint District, Federal and State Project for the Evaluation of
Refinery Emissions," Los Angeles County Air Pollution Control District,
Nine reports 1957-1958.
4, U. S. EPA, Office of Air Quality Planning and Standards, MDAD-
MRB, "National Air Quality and Emission Trends Report 1975," EPA-450/1-
76-002, Research Triangle Park, North Carolina 27711, November 1976.
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REFINERY PROCESS DRAINS AND WASTEWATER SEPARATORS
Process Description
Petroleum refineries generate large quantities of process wastewater.
Depending on many factors, a refinery may generate up to one barrel of
wastewater for every barrel of crude oil throughput. Process wastewater
originates from several sources in petroleum refineries including, but not
limited to, crude desalting, leaks, spills, pump and compressor seal cooling
and flushing/sampling, and equipment cleaning. Contaminated wastewater is
collected in the process drain system and directed to the refinery treat-
ment system where oil is skimmed in a separator and the wastewater undergoes
additional treatment as required.
Base Line Emissions
The nationwide hydrocarbon emissions from petroleum refinery process
drains and wastewater separators are estimated to be 295,000 metric tons
per year based on January 1, 1977, throughput of 2.69 million cubic meters
2
of crude oil per day. This is approximately 1.6 percent of the nationwide
3
stationary source emissions of hydrocarbons.
Control Technology
Controls for refinery process drains and wastewater separators consist
of 1) the refinery operator should perform a monthly monitoring program
for detection of hydrocarbon concentrations above 100 ppm as hexane at
5 centimeters.from the process drains and wastewater separators and 2) floatin
roof covers for all forebays and all initial wastewater separators. The
monitoring program is necessary to ensure that no excess hydrocarbons have
been released into the drain system and that all hatches remain closed
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when not in use. The covers are necessary to ensure that the volatile
hydrocarbons are returned to the system (crude desalter unit usually)
before they can evaporate to the atmosphere. Application of these controls
will result in an estimated 90 percent reduction in emissions from these
sources.
There are important considerations that need to be taken into account
when covering a wastewater separator. When using a floating roof cover,
care must;be taken'to ensure that the cover'wilV'not interfere with the
••operation of the oil skimmer. Fixed roof covers can have a vapor space
between the cover>and the liquid surface, this vapor space may constitute
an explosion hazard unless it is gas-blanketed with hydrocarbon or nitrogen
- ;4
-and vented to a flare.
Cost -of Control
The H976'•estimates'for-cos4:-e^
separators -by installing flo'ati rig* roof -covers 'for the forebay and main
separator are a cre:dit of $70.48 and $79.73 per metric ton of emissions
45
reduced .for a 9850 and a 31,800 cubic meter per day refinery, respectively. '
The cost of the portable hydrocarbon analy'zier needed for the monitoring
.program "should'range from $800 to $4000 each, depending on the type of
instrument used. Although'no rigorous cost-effectiveness analysis has been
•performed for the 'Teak detection plan, it is felt that the costs will be
appreciably off-set ;by savings from-product recovery.
References
1. "Control of Hydrocarbon Emissions from Miscellaneous Refinery
Sources," EPA guideline document in preparation to be released in 1977.
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2. Annual ;Refining Survey, The Oil and Gas Journal, March 28, 1977.
3. U. S. EPA, Office of Air Quality Planning and Standards, MDAD-MRB,
"National Air Quality and Emission Trends Report 1975," EPA-450/1-76-002,
Research Triangle Park, North Carolina 27711, November 1976.
4. "Hydrocarbon Emissions from Refineries," Committee on Refinery
Environmental Control, American Petroleum Institute Publication No. 928,
July 1973.
5. "Economic Impact of EPA's Regulations on the Petroleum Refining
Industry," U. S. EPA, Office of Planning and Evaluation, Report Number
230/3-76-004, April 1976.
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REFINERY VACUUM PRODUCING SYSTEMS
Process Description
Bottoms from the atmospheric distillation tower can be further
fractionated if the temperature is increased and the pressure is lowered.
This is performed in the vacuum distillation tower. Three types of vacuum
producing devices are used to remove gases and vapor from the tower: steam
jets with barometric condensers, steam jets with surface condensers, and
mechanical vacuum pumps. The educted vapors and evaporation from the
accumulators or hot wells(barometric condensers only) are potential
hydrocarbon emissions from refinery vacuum producing systems.
Base Line Emissions
Based on January 1, 1977, refinery capacity (2.69 million cubic meters
inc
2
per day), The hydrocarbon emissions from the refinery vacuum producing system!
are estimated to amount to approximately 127,000 metric tons per year.'
This is about 0.7 percent of the total stationary source hydrocarbon
emissions.
Control Technology
The non-condensable gases should either be vented directly to a
combustion device or compressed and added to the refinery fuel gas system.
The hot wells and accumulators should be covered and vented to a combustion
device. Implementation of these controls will result in negligible
emissions of hydrocarbon to the atmosphere.
Energy Requirements
There will be an energy requirement for the non-condensable gas
compressor if one is used, but this requirement will more than be off-set
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by the savings from the recovered hydrocarbons. A 15,900 cubic meter per
day refinery will recover the equivalent of 1300 cubic meters of crude oil
per day. Other energy requirements for the controls listed are minimal.
Cost of Control
Estimates of the cost-effectiveness of compressing the non-condens-
ables and incinerating them in the nearest firebox are a credit of $31.16
per metric ton of hydrocarbon emissions reduced. This is based on a
45
15,900 cubic meter per day refinery operating in 1973. ' This estimate
does not include the cost of a condensate receiver for a surface condenser
or the cost of covering the barometric hot well.
References
1. Annual Refining Survey, The Oil and Gas Journal, March 28, 1977.
2. "Control of Hydrocarbon Emissions from Miscellaneous Refinery
Sources," EPA guideline document in preparation to be released in 1977.
3. U. S. EPA, Office of Air Quality Planning and Standards, MDAD^MRB,
"National Air Quality and Emission Trends Report 1975," EPA-450/1-76-002,
Research Triangle Park, North Carolina 27711, November 1976.
4. "Hydrocarbon Emissions from Refineries," Committee on Refinery
Environmental Control, American Petroleum Institute Publication No. 928,
July 1973.
5. "Economic Impact of EPA's Regulations on the Petroleum Refining
Industry," U. S. EPA, Office of Planning and Evaluation, Report Number
230/3-76-004, April, 1976.
23
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REFINERY PROCESS UNIT TURNAROUND
Process Description
Periodically every refinery processing unit must be shut down for
maintenance. The shutting down, purging and restarting of a unit is
called a turnaround. In short, when a unit is shut down, the hydrocarbon
liquids are pumped to storage and the hydrocarbon gases are purged from
the vessel. It is then ventilated to provide a safe atmosphere for
workmen. The emissions that occur as a result of the shutting down is
called blowdown. Unit turnarounds occur every one to five years depending
on many factors.
Base Line Emissions
The nationwide hydrocarbon emission estimate for refinery blowdown
systems is 450,000 metric tons per year, based on January 1, 1977, capacity
2
of 2.69 million cubic meters of crude oil throughput per day. This is
approximately 2.5 percent of the total stationary source emissions of
hydrocarbons.
Control Technology
Controls for refinery blowdown systems consist of combusting the
non-condensable vapors. When the vessel is dep^essarized, the non-condensable
vapors can be--either added to tte refinery fye3vg3S."*a#stem or
the ^pressure in the vessel dropsK'fcelow that of;4$tetjlie1 gas
vapors are then combusted in the flare. This should continue at l^ast
until the hydrocarbon concentration in the vessel drops below 10 percent
by volume. The vessel is then ventilated to atmosphere to allow maintenance
personnel to enter. Application of these controls will result in emissions
of 2300 metric tons per year from process unit turnaround.
24
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Cost of Control
Since the control technology described above is presently being applied
in several refineries, it appears the controls are justifiable either in
terms of recovered product or refinery safety. Piping costs are involved
with attaching some of the units to existing fuel gas and flare systems;
these costs should be minimal.
References
1. "Control of Hydrocarbon Emissions from Petroleum Liquids," U. S.
EPA Report No. 600/2-75-042, September, 1975.
2. Annual Refining Survey, The Oil and Gas Journal, March 28, 1977.
3. U. S. EPA, Office of Air Quality Planning and Standards, MDAD-MRB,
"National Air Quality and Emission Trends Report 1975," EPA-450/1-76-002,
Research Triangle Park, North Carolina 27711, November, 1976.
25
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LEAKS FROM NATURAL GAS AND NATURAL GASOLINE PROCESSING PLANTS
Process Description
Natural gas is produced in conjunction with crude oil, natural gas
liquids, water, carbon dioxide, and hydrogen sulfide. The crude oil and
water are generally separated from the gases near the wellhead. Gas free
crude and other liquids are stored for eventual transfer to the refinery.
The remaining liquids and gases are sent to a gas plant where" the liquids,
hydrogen sulfide, carbon dioxide, and C2 to C,- hydrocarbons are separated
from methane before it is placed in the pipeline. The emissions and
control techniques described below apply only to the natural gas and
natural gasoline plant not to any facilities between the wellhead and
the gas plant.
Base Line Emissions
The nationwide hydrocarbon emission estimate for natural gas and
natural gasoline processing plants is 152,000 metric tons per year, based
on 1973 estimates of 1.86 billion normal cubic meters of production per
day. This is about 0.9 percent of the total stationary source hydrocarbon
emissions.
Control Technology
Oil-water separators, pump and compressor seals, pressure relief
devices, and pipeline valves and flanges are the sources of hydrocarbon
emissions. These emissions occur as a result of leaks. One of these
components is deemed to be leaking if there is a concentration of 100 ppm
hydrocarbon as hexane at a distance of 5 centimeters from the component.
The leaks will be minimized if the oil-water separators are covered,
mechanical seals are used on all rotating pumps and compressors, all
pressure relief devices are vented to flares or protected by rupture discs,
26
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and if a regular program of leak detection and maintenance is followed.
The frequency with which each type of component should be individually
checked for leaks is 1) oil-water separators - monthly; 2) pump and
compressor seals - daily; 3) pressure relief devices - monthly; and
4) pipeline valves - monthly. Also the ambient air concentrations should
be measured daily throughout the plant using a portable hydrocarbon
detector. The source of any ambient hydrocarbon readings over 20 ppm
should be located and repaired if the source is in excess of the 100 ppm
level. Application of the above controls will result in an estimated
91 percent reduction in hydrocarbon emissions from these sources.
Energy Requirements
Implementation of these controls will have a minimum impact on energy
use and can result in an energy savings due to decreased losses of hydro-
carbon product.
Cost of Control
Since the control equipment discussed above are presently being
applied in many plants, it appears the controls are justifiable either in
terms of cost-benefit for recovered product or refinery safety. Even
though additional instrumentation and personnel may be needed to implement
the leak detection and maintenance plan, these costs will be off-set by
savings from product recovery. The cost of a portable hydrocarbon detector
should range from $800 to $4000 each, depending on the type of instrument
used. Therefore no rigorous cost-benefit analysis has been developed
since the cost impact will be minimal.
References
1. "Control of Hydrocarbon Emissions from Petroleum Liquids" U. S.
EPA Report No. 600/2-75-042, September, 1975.
27
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2. U. S. EPA, Office.of Air Quality Planning and Standards, MDAD-MRB,
"National Air Quality and Emission Trends Report 1975," EPA-450/1-76-002,
Research Triangle Park, North Carolina 27711, November, 1976.
3. "Control of Hydrocarbon Emissions from Miscellaneous Refinery
Sources," EPA guideline document in preparation to be released in 1977.
28
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LEAKS FROM OIL AND GAS PRODUCTION FIELDS
Process Description
In a producing oil well, there are three basic methods of bringing
the oil to the surface: natural flow, steam or water lifting (injection
of steam or water into the well), and pumpiag. Oil and gas production
i.
operations include the separating and transferring of oil and gas. The
production from each well is sent to a gathering system Which consists
of the piping, valves, and fittings that are necessary to collect and
combine the production from the individual wells.
Crude oil and natural gas liquids are produced in association with
gases and water which must then be treated to separate crude oil from
gas and water. The gas free crude and other petroleum liquids are
stored for eventual transfer to the refinery. The gases are then piped
to a gas plant where any remaining liquid hydrocarbon, hydrogen sulfide.
carbon dioxide, and C2 to C5 hydrocarbons are separated before the methane
is placed in the pipeline. The control techniques described below apply
to the well head equipment, heater treaters, separators, and the piping
and valves up to but not including the gas plant.
Base Line Emissions
Leaks from pump seals, compressor seals, relief valves, open crude
ponds, and pipeline valves are the source of hydrocarbon emissions from
production fields. The nationwide hydrocarbon emission estimate of
148,000 metric tons per year1 for crude and gas production is extremely
rough.
29
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Control Technology
Effective control of potential leaks requires a good detection and
maintenance program. Any leak which exceeds 100 ppm at a distance of
2
5 cm from the source would require maintenance. All potential leak
sources should be checked monthly with a portable hydrocarbon detector.
Ponds or other types of open crude storage should be eliminated and
replaced by storage tanks.
Costs of Control
The cost of the maintenance program is dependent on the size of the
field, the number of sources, and the degree of maintenance employed but
is not expected to be significant. The hydrocarbon detector would cost
about $800 to $4,000.
References
1. "Control of Hydrocarbon Emissions from Petroleum Liquids,"
Radian Corporation. September 1975.
2. "Control of Hydrocarbon Emissions from Miscellaneous Refinery
Sources," EPA guideline document in preparation to be released in 1977.
30
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CUTBACK ASPHALT PAVING
Process Description
Asphalt is a by-product of petroleum distillation (natural or
manmade) which is used in many different paving applications. Asphalts
take the form of asphalt cement (the residue of the distillation of
crude oils) and liquefied asphalts. Liquefied asphalt is frequently
thinned with volatile petroleum distillates (cutbacks) such as naphtha
and kerosene. Heat is used with cutbacks to facilitate spraying. The
volatiles in cutback asphalts release hydrocarbons into the atmosphere
in amounts that vary according to the type of cutback.
Baseline Emissions
The national hydrocarbon emission estimates from the use of cutback
asphalt paving products was 672,000 metric tons per year in 1975.
Control Technology
The technology to control hydrocarbon emissions from these paving
operations consists of substituting emulsified asphalts in place of
cutback asphalts. Emulsified asphalts use water and non-volatile emulsifying
agents for liquefaction; virtually no pollutants are emitted during the
curing of emulsions. Emulsified asphalts are used widely in the construction
and maintenance of pavements ranging from high traffic volume highways and
airports to low-volume rural roads and city streets. Emulsions have been
available since 1903 and used extensively since the 1930's.
31
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Energy Requirements
The substitution of emulsions for cutbacks could save almost 1.59
billion liters of petroleum distillate annually for use as or conversion to
fuels and eliminate the 672,000 metric tons of hydrocarbons currently
being emitted to the atmosphere. Also, much of the energy required to
heat the cutbacks would be saved.
Environmental Considerations
There are no adverse environmental effects associated with the
substitution of emulsified asphalt for cutback asphalt.
Costs of Control
The price difference between the two types of liquefied asphalt
concrete is insignificant. Therefore, there is no control cost
associated with the substitution.
Factors Which Affect Applicability - Emulsified asphalt can be substituted
for cutbacks in almost any application. Some emulsified asphalts, however,
usually are not used when rain is anticipated or when temperatures fall
below 10°C. Emulsified asphalt is not recommended for long-term stockpiling
(more than 3-4 weeks) whereas cutback asphalt can be stockpiled indefinitely.
The same construction equipment used for cutbacks can be used for emulsions.
A moderate amount of training (one or two days) is necessary to familiarize
operators with technology for employing emulsions.
32
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References
"Some Air Quality and Energy Conservation Considerations for the
Use of Emulsions to Replace Asphalt Cutbacks in Certain Paving Operations,"
Prepared by Francis M. Kirwan and Clarence Maday, U. S. Environmental
Protection Agency, March 1977, draft report.
33
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COLD CLEANING WITH ORGANIC SOLVENTS
Process Description
Cold cleaners are tanks of organic solvent used for cleaning or
degreasing metal parts at or near room temperature. Metal parts
may be cleaned manually by spraying and brushing or automatically
by immersion into an agitated solvent bath. Automotive parts
cleaning and plant maintenance are normally performed using cold
cleaning because it is inexpensive and there is no need for the
cleanliness obtainable with vapor degreasing. There are an estimated
1,300,000 cold cleaners in operation in the United States.
Base Line Emissions
An estimated 360,000 metric tons of organic solvents were emitted
as a result of cold cleaning in 1974. Evaporation of disposed waste
solvent accounted for over half of the total. The solvents included
aliphatic (50 percent), halogenated (34 percent), aromatic (10 percent),
and oxygenated (6 percent) organics. Three-fourths of the halogenated
solvent used were methyl chloroform, methylene chloride, and trichloro-
(g\
trifluoroethane (Freon 113^. All three react very slowly in the atmos-
phere yielding negligible oxidant. However, because of their chemical
stability, they pose a threat to the earth's ultraviolet shield in that
they may deplete ozone in the stratosphere.
Control Technology
Emission standards are not practical because degreasing is by nature
an open operation that prevents complete capture or measurement of emissions,
34
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Equipment and operating standards appear to be the only viable alternatives.
Emission control is accomplished through both improved operating
practices and addition of control equipment. The most important operating
improvements are: (1) store and then dispose of or distill waste solvent
so as to minimize atmospheric evaporation, (2) close covers on cold cleaner
tanks whenever possible, and (3) drain cleaned parts sufficiently. The
basic control equipment is the cover and a parts drainage facility. These
should be standard on cold cleaners. For cleaners using high volatility
solvents (greater than 33 mm Hg vapor pressure at 38°C), important
control devices are the water cover (for halogenated solvents) and a
high freeboard (the clearance as measured from the so-1 vent level to the
top of the cleaner).
Controls on waste solvent disposal can reduce total cold cleaning
emissions by 10 to 40 percent; controls on direct emissions can reduce
emissions by an additional 10 to 30 percent, for a total efficiency of
20 to 70 percent.
Energy Requirements
No significant energy is consumed to control cold cleaners. Distillatio
consumes approximately 0.3 kilowatt-hour per kilogram of waste solvent
compared to approximately 25 kilowatt-hours per kilogram required to
produce replacement solvent.
References
1. "Control of VOC from Organic Solvent Metal Cleaning Operations,"
EPA Guideline Document in preparation to be released in 1977.
35
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2. "Study to Support New Source Performance Standards for Solvent
Metal Cleaning Operations," Dow Chemical Company, Prepared for EPA
under Contract No. 68-02-1329, Task No. 9.
36
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Control Cos!ts
Typical Retrofit Cases
Solvent Used
Control Devices
Capital Annualized
Cost Cost (Credit)
($) ($/yr)
Cost (Credit) Emissit
Effectiveness Reducti
($/kg controlled) (kg/y»
Low Volatility Drainage Facility
(Mineral Spirits)
25
0.5
0.3-(0.07)
25
High Volatility
(e.g. blended
solvent with
60% methyl
chloroform)
Drainage Facility,
Mechanically
assisted cover
65
(25)
(0.08)-(0.3)
100
37
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VAPOR DECREASING
Process Description
A vapor degreaser is a tank in which metal parts are cleansed
by the washing action of condensing solvent. Vapors are contained within
the tank by means of cooling coils near the top. Only non-flanmable
halogenated solvents are employed in vapor degreasers. The cleaning
process may be assisted by spraying or by immersion into the boiling
liquid solvent. Open top vapor degreasers are by definition open and
are batch loaded; conveyorized degreasers are enclosed and are
continuously loaded. The most recent estimates indicate that there
are about 4000 conveyorized and 22,000 open top vapor degreasers in
operation in the United States.
Base Line Emissions
In 1974, vapor degreasing operations resulted in approximately
300,000 metric tons of organic solvent emissions. One-third came
from conveyorized and two-thirds from open top degreasing.
Halogenated organics are always used for vapor degreasing because
of non-flammability and high vapor density. In decreasing order of
usage, the predominant solvents are trichloroethylene, 1,1,1 trichloro-
ethane (methyl chloroform), perchloroethylene, trichlorotrifluoroethane
(Freon 113^ and methylene chloride.
Control Technology
For most vapor degreasers, it is difficult or impossible to measure
emissions directly. Furthermore, emissions tend to vary widely depending
upon the type of parts being degreased, solvents and operating practices.
38
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Thus, losses do not necessarily reflect the degree of control being
exercised. For these reasons, equipment and operating standards appear
to be the most viable control approaches.
Open Top Vapor Degreasers - Organic emission reductions are
accomplished through both improved operating practices and installation
of control equipment. The ten most effective operating practice improve-
ments are: (1) keep cover closed whenever possible, (2) minimize solvent
carry-out by proper parts racking, convey parts at less than 3.3 meters
per second, cook work loads for at least 30 seconds and dry for at least
15 seconds, (3) do not degrease porous materials, (4) do not process work
loads that occupy more than 50 percent of the horizontal open area,
(5) do not let the vapor level drop more than 10 centimeters below
normal, (6) do not spray above the vapor level, (7) repair leaks
immediately, (8) store and then dispose of or distill waste solvent
so as to minimize atmospheric evaporation, (9) maintain exhaust
ventilation below 20 meters per minute per square meter of air/vapor
interface, and (10) ensure that the water separator operates properly.
Control equipment and features which reduce emissions are covers,
safety switches, .increased freeboard, refrigerated chillers, enclosed
design and carbon adsorbers. A complete control system would include
the first two devices and one of the last three.
Covers may be manually operated, mechanically assisted, powered
or automated, but the crucial factor is that they be convenient to operate.
Safety switches should be designed to cut off the spray if the vapor
level drops too low, and to cut off the sump heater if the sump overheats
39
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or the cooling coils cease functioning. A minimum freeboard ratio
(freeboard height divided by degreaser width) of at least 0.5 is
recommended by degreaser manufacturers, but it should be as large
as possible consistent with ease of inserting and removing parts.
Refrigerated chillers cool the air immediately above the vapor zone
to impede outward diffusion and convection of vapors. An enclosed
design keeps the cover closed at all times except when dry parts are
actually entering or exiting the degreaser. Carbon adsorption systems
are effective organic vapor control devices but are limited in degreasing
by the difficulty in capturing fugitive emissions.
Use of all ten operating practices may reduce emissions by 20 to
40 percent; the control equipment and design features may reduce them
by an additional 30 to 60 percent, for an overall efficiency of 45 to
75 percent.
Conveyorized Degreasers - For control of conveyorized units, the
most effective operating practices are: (1) repair leaks immediately,
(2) store and then dispose of or distill waste solvent so as to minimize
atmospheric evaporation, (3) maintain exhaust ventilation below 20 meters
per minute per square meter of air/vapor interface, (4) ensure that the
water separator operates properly, (5) minimize solvent carry-out by
proper parts racking, and (6) convey parts at less than 3.3 meters per
second.
Control equipment and features which reduce emissions are safety
switches, refrigerated chillers, carbon adsorption, minimized conveyor
openings and downtime cover. Safety switches, refrigerated chillers,
and carbon adsorption were discussed earlier. The entrance and exit
40
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opening for conveyed parts should, be as small as possible to minimize
vapor escape; all openings should be covered during shut down to
prevent vapors from escaping.
A complete control system for a conveyorized unit with all of the
devices listed, i.e., chiller or adsorber (but not both), will reduce
VOC emissions by 50 to 70 percent.
Energy Requirements
Carbon adsorption requires energy, usually in the form of steam
for desorption. The steam requirement is typically 5 kilowatt-hours
per kilogram solvent recovered. This energy expenditure is more than
offset since production of replacement solvent consumes about 25 kilowatt-
hours per kilogram.
References
1. "Control of VOC from Organic Solvent Metal Cleaning Operations,"
OAQPS guideline document to be released in 1977.
2. "Study to Support New Source Performance Standards for Solvent
Metal Cleaning Operations," Dow Chemical, prepared for EPA under contract
no. 68-02-1329, Task No. 9.
41
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Control Costs (retrofitted)
Major Control Device Option
For Typical Open Top Vapor
Degreaser: (1.67 m2 area)
Capital Costs ($)
Avg. Annual i zed Cost
.Manual
Cover
300
(800)
Freeboard
& Powered
Cover
8000
310
Re frig.
Chiller
6500
85
Enclosed
Design
16,000
35
Carbon
Adsorption
10,300
800
(Credit)($/yr)
Cost (Credit) Effectiveness (0.4)
($/kg controlled)
Emission Reduction (metric 1.1-3
ton/yr)
0.4-(0.04) 0.03-(0.1) 0.2-(0.1) 0.5-0.06
1.7-3.8 2.3-4.2 6.1-4.2 2.3-4.6
For typical Conveyprized
Degreasers: (3.8 n£ vapor
area)
Monorail Deg.
Adsorber Chiller
Cross-Rod Deg.
Adsorber Chiller
Capital Cost ($)
Avg. Annualized Cost
(Credit) ($/yr)
Cost (Credit)
Effectiveness
($/kg controlled)
Emission Reduction
(ton/yr)
17,600
(1,600)
8,600
(3,700)
17,600
(1,500)
7,500
(650)
(0.03)-(0.19) (0.24)-(0.32) (0.53)-(0.14) (0.016)-(0.19)
10-17
10-17
4-7
4-7
42
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GRAPHIC ARTS
ROTOGRAVURE PRINTING OPERATIONS
Process Description
In the gravure method of printing, the very fluid inks fill the recessed
image areas, excess ink is wiped off by a doctor knife, the image is trans-
ferred directly to the paper or other substrate and the product is dried.
When the paper is fed from a roll, the process is known as rotogravure.
Since sheet-fed gravure is slow, it is little used and is not included in
this subject category.
Base Line Emissions
The emission from rotogravure presses are estimated to be 140,000
metric tons per year.
Control Technology
Carbon adsorption has been successfully used at several large publication
2
rotogravure plants. Overall recovery efficiency is about 90 percent, giving
an emission level of 0.05 kilograms per liter of ink.
Packaging and specialty gravure printers use a wide range of solvents
2
depending upon the substrate to be printed. Carbon adsorption may be more
expensive for such operations because of the difficulty or impossibility of
reusing the recovered solvents. Fume incineration has been used in a few
instances. Overall efficiency is 85 to 90 percent with a resultant emission
level of 0.07 kilograms per liter of ink. Although water-borne inks are used
43
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for certain specialties, they are not available for all uses.
Cost of Control
The cost of carbon adsorption units ranges from $170,000 for a
single press plant to over $1,000,000 for a large publication printing
plant. Annual costs, without solvent reuse, are $70,000 and $520,000
or $250 and $120 per metric ton of solvent controlled for a small and
large plant respectively. With solvent reuse, a profit would be assured
since rotogravure ink solvents cost about 10 cents per kilogram. Additional
details on costs are given in Reference 3.
Installed costs of incinerators without heat recovery range from
$100,000 for a small (2.4 Nm3/s) plant to $325,000 for a large (43 Nm3/s)
plant.3 Annual costs would be about $100,000 and $1,000,000, respectively,
or $275 and $185 per ton. With primary and secondary heat recovery,
installed costs would be $140,000 and $500,000 respectively. Annual costs
would be $34iOOO and $220,000, respectively, or $120 and $40 per ton.
More details on incinerator costs are given in Reference 3.
References
1-. Gadomskii R. R., et. al., "Evaluations of Emissions and Control
Technologies in the Graphic Arts Industries, Phase I," Graphic Arts
Technical Institute, August 1970.
2. "Environmental Aspects of Chemical Use in Printing Operations,"
EPA-560/1-75-005, Office of Toxic Substances, U. S. Environmental
Protection Agency, January 1976.
3. "Control of Volatile Organic Emissions From Existing Stationary
Sources - Volume I: Control Methods for Surface Coating Operations,"
EPA-450/2-76-028, U. S. Environmental Protection Agency, November 1976.
44
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GRAPHIC ARTS ;
WEB-OFFSET PRINTING OPERATIONS
Process Description ;
In offset lithography, the printing and non-printing areas of the
image carrier are on the same plane. The image areas are sensitized so
as to be ink wettable and water repellent. The image is first transferred
to a rubber covered roll (called a blanket) and hence is transferred to
the paper. The image carrier is thus "offset" from the substrate. The
paper is fed to the press from a roll and forms a continuous "web" as it
travels through the printing and drying operations.
Base Line Emissions
It is estimated that web-offset presses emit 100,000 metric tons per
year of VOC.]'2
Control Technology
A number of direct flame incinerators have been installed to control
emissions from web-offset dryers. Nineteen test reports show an average
3
efficiency of 95 percent. Conventional inks average about 45 percent
organic solvent by volume, and contain 0.36 kilgrams per liter. Allowing
for a slight loss of capture, overall efficiency is 90 percent, equivalent
to an emission level of 0.036 kilograms per liter of ink used.
Eight test reports on catalytic incinerators averaged 89 percent
efficiency. Allowing for a slight lack of capture, overall efficiency is
85 percent. Achievable emission level is 0.054 kilograms per liter of
ink.
45
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Ultraviolet curing inks eliminate the use of solvent. The vehicle
of the ink consists entirely of monomers and prepolymers which polymerize
under the influence of heat and a catalyst. Since time and temperature
requirements are about the same as for drying conventional ink, conventional
dryers can be used. The inks contain some organic solvent, averaging
a
about 15 percent of the solvent content of conventional inks. Emission
rates are about 0.054 kilograms of VOC per liter of ink.
A carbon adsorption system has been used in one web-offset printing
plant. Conventional heat-set inks are used, averaging about 45 percent
solvent. Overall-recovery efficiency is about 90 percent,equivalent to
an emission level of about 0.036 kilograms per liter of ink used.
Cost of Control
The costs of incineration for web-offset presses are the same as
those cited for rotogravure printing. Additional details on costs are
given in Reference 5.
In Reference 5, page 262, it is estimated that ultraviolet curing inks
cost two or three times as much as conventional inks. The cost of hardware
to replace the existing oven is considerable, but no specific figures are
available. However, the cost of operating a UV unit is less than the fuel
cost of a conventional oven.
The cost of heat-reactive inks is reported to be 140-200 percent of the
5
of conventional inks. Sim
is no additional equipment cost.
5
cost of conventional inks. Since conventional ovens can be used, there
46
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A carbon adsorption system controlling a web-offset printing plant
3 5
is reported to have a capital cost of 3.3 to 4.7 cents per Nm /s.
3
Presumably, installed cost would be 6.6 to 9.4 cents per Nm /s. In the
desorption and recovery process in this system, electric heaters, vacuum
pumps, and refrigerated condensers are used. The cost of conventional
systems using steam for desorption are given in Reference 4.
References
1. Gadomski, R.R., et.al.."Evaluations of Emissions and Control
Technologies in the Graphic Arts Industries, Phase I". Graphic
Arts Technical Institute, August 1970.
2. Test Report Summaries. Los Angeles County Zone, South Coast Air
Quality Management District. El Monte, California.
3. Gadomski, R.R., et.al., "Evaluations of Emissions and Control
Technologies in the Graphic Arts Industries, Phase II" Graphic Arts
Technical Institute, May 1973.
4. "Environmental Aspects of Chemical Use in Printing Operations."
EPA-560/1-75-005. Office of Toxic Substances, Environmental Protection
Agency, January 1976.
5. "Control of Volatile Organic Emissions from Existing Stationary Sources -
Volume I: Control Methods for Surface Coating Operations I1 EPA-450/2-76-02
U.S. Environmental Protection Agency, November 1976.
47
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GRAPHIC ARTS
WEB LETTERPRESS PRINTING OPERATIONS
Description of the Process
In the letterpress method of printing, the image areas are raised
relative to the nonimage areas. This is the original method of printing
with type. Ink is applied to the image areas and transferred directly
to paper or other substrate. The ink is viscous enough not to run into
the recessed (nonimage) areas.
Letterpress printing can be divided into three categories. Newspaper
printing ulitizes ink composed of petroleum oils and carbon black, but no
volatile solvent. The ink "dries!l by absorption into the porous newsprint
paper. Roll-fed (web) presses utilizing nonporous paper employ organic
solvent-borne inks which dry by solvent evaporation. Sheet-fed presses
ulitize a non-solvent ink which dries'by air oxidation at room temperature
in racks. Only web presses using solvent-borne inks are included in the
subject category.
Base Line Emissions
The total national annual emissions of VOC web letterpress are
estimated to be 78,000 metric tons.
Control Technology
A number of incinerators have been installed to control print dryers*,
Test reports siiov; an average efficiency of 95 percent. ' Allowing for a
48
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slight loss of capture, overall efficiency is 90 percent, comparable
to an.emission level of 0.036 kilograms per liter of ink used.
Ultra-violet curing inks eliminate the use of volatile solvents.
The vehicle of the ink consists entirely of monomers and prepolymers
which polymerize to a dry resin film in a few seconds in an ultra-violet
light chamber. Emissions are essentially zero.
Heat reactive inks reduce the use of solvents. The vehicle for these
inks consists mostly of monomers and prepolymers which polymerize under
the influence of heat and a catalyst. Time and temperature requirements
are about the same as for drying conventional inks, hence conventional dryers
can be used. The inks contain only about 15 percent of the organic solvent
content of conventional inks. Emission rates are about 0.054 kilograms per
1i ter.
Conventional heat-set inks averaging about 45 percent solvent can be
controlled with carbon adsorption. Overall recovery efficiency is about 90
percent. Achievable emission level is about 0.036 kilograms per liter of
ink used.
/
Water-borne inks are used in some letterpress applications and can
achieve an emission level of 0.06 kilograms of VOC per liter of ink (minus
water) representing a reduction of 80 percent over a typical heat-set ink.
Cost of Control
The cost of incineration for letterpress operations are similiar to
those cited earlier for rotogravure printing. Additional details are given
in Reference 4.
49
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In Reference 3, page 262, it is estimated that ultraviolet curing
inks cost 2 to 3 times as much as conventional inks. The cost of the
hardware to replace the existing oven would be considerable, but no
specific figures are available. However, the cost of operating a UV
unit is less than the fuel cost of a conventional oven.
The cost of heat-reactive inks is reported to be 140 to 200 percent
of the cost of conventional inks. Since conventional ovens can be used,
there is no additional equipment cost for a changeover.
The hardware of a carbon adsorption system controlling a web-offset
3
printing plant is reported to cost 3.3 to 4.7 cents per Mm /s. Presumably
o
installed cost would be 6.6 to 9.4 cents per Mm /s. In the desorption and
recovery process in this system, electric heaters, vacuum pumps, and
refrigerated condensers are used. The cost of conventional systems
using steam for desorption is given in Reference 4.
V
References
1. Gadomski, R. R., "Evaluations of Emissions and Control Technologies
in the Graphic Arts Industries, Phase II," Graphic Arts Technical Institute,
May 1973.
2.. Gadomski, R. R., "Evaluations of Emissions and Control Technologies
in the Graphic Arts Industries, Phase I," Graphic Arts Technical Institute,
August 1970.
3. "Environmental Aspects of Chemical Use in Printing Operations,"
EPA-560/1-75-005, Office of Toxic Substances, U. S. Environmental
Protection Agency, January 1976.
50
-------
4. "Control of Volatile Organic Emissions from Existing Stationary
Sources - Volume I: Control Methods for Surface Coating Operations,"
EPA-450/2-76-028, U. S. Environmental Protection Agency, November 1976.
5. Test Reports from the Los Angeles County Zone, South Coast Air
Quality Management District, El Monte, California.
51
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GRAPHIC ARTS
FLEXOGRAPHIC PRINTING OPERATIONS
Process Description
In flexographic printing, like letterpress, the image areas are
raised above the nonimage surface. The distinguishing feature is that
the image carrier is made of rubber. Flexographic presses are usually
rotary web presses, i.e., roll-fed. The major categories of the flexo-
graphic market are: flexible packaging and laminates, multiwall bags,
milk cartons, folding cartons, corrugated paper, paper cups and plates,
labels, tags, tapes,, envelopes and gift wrap.
Flexography uses very fluid inks, typically about 60 percent organic
solvent. The inks dry by so.lvent evaporation, usually in high velocity air
dryers at temperatures generally below 121°C.
Base Line Emissions
It is estimated that flexographic presses emit 58,000 metric tons per
2
year of VOC.
Control Technology
A few flexographic presses are controlled by incineration. One test
report of a direct-flame incineration showed a control efficiency of 98
3
percent. No test reports of catalytic incinerators have been received,
but the technique appears to be applicable, unless fouling or poisoning
substances are present. No such materials are evident in flexography.
52
-------
2. Gadomski, R.R., et.al., ''Evaluations of Emissions and Control Tech-
nologies in the Graphic Arts Industries, Phase I. Graphic Arts
Technical Institute, August 1970.
3. Test Reports from Los Angeles County Zone, South Coast Air Quality
Management District. El Monte, California.
4. "Control of Volatile Organic Emissions from Existing Stationary Sources
Volume I: Control Methods for Surface Coating Operations",
EPA-450/2-76-028. U.S. Environmental Protection Agency, November 1976.
54
-------
With a typical ink of 60 percent organic solvent, an incinerator system
with an overall efficiency of 85 percent would have an overall efficiency
of 85 percent and would have an achievable emission level of 0.07 kilogram
per liter of ink.
Water-borne inks are used in several types of flexography applications,
A typical water-borne ink can achieve an organic emission level of 0.1
kilogram per liter of ink (minus water), representing a reduction of 80
percent over a typical solvent-borne ink.
Ultraviolet curable and heat reactive inks have not been developed
with the low viscosity and other properties required for flexographic
inks, but there is a potential for their use. Since most of the solvents
used in flexographic inks are water soluble, a carbon adsorption system
using conventional steam desorption would require a distillation system
to recover the solvents. This wouTd be a deterrent but the method is
potentially viable.
Cost of Control
The costs of incineration for flexographic presses would be similar
to those cited above for rotogravure printing. Additional details are
given in Reference 4.
The costs of water-borne inks are comparable to those of solvent-
borne inks. Fuel cost for drying may be increased slightly.
References
1. "Environmental Aspects of Chemical Use in Printing Operations",
EPA/560/1-75-005. Office of Toxic Substances, Environmental Protection
Agency, January 1976.
53
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RUBBER TIRE INDUSTRY
Part 1 - CAMELBACK OR TREAD END MANUFACTURE
Process Description
This operation involves the use of organic solvent-borne cement
to "tackify" the tire tread after extrusion but before it is used to
build tires. The extruded tread-sidewall is assembled, cut to proper
length and the ends are coated with rubber cement. The solvent, generally
naptha, evaporates rapidly as the tread is conveyed through the building.
Base Line Emissions
The emission factor for undertread cementing is estimated to be 28
grams per tire. Since 250,000,000 tires are produced annually in this
country, these emissions amount to 7,000 metric tons per year.
Control Technology
The control system consists of a collection system (to collect the
evaporated solvent from organic solvent-borne cement spray originating
from the spray operation and conveyors) and a control device (carbon
adsorber). Collection efficiency is 90 percent and adsorption efficiency
is 95 percent for an overall control efficiency of 85 percent. This
technology is not in widespread use in the industry but has been used at
several plants.
Cost of Control
The costs of carbon adsorption for this source are presented in
Table 1. When the recovered solvent is credited at its market value,
there is a net cost savings when a carbon adsorber is installed in a plant.
55
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Table 1. CARBON ADSORPTION COSTS FOR A,TYPICAL
UNDERTREAD CEMENTING OPERATION3
Annualized Control cost,
operating $/ton of
Capital cost, hydrocarbons
Incineration device cost, $ $/year removed
Case with no credit for recovered 180,000 65,000 160
solvent
Case with recovered solvent 180,000 35,000 85
credited at fuel value
Case with solvent credited at 180,000 (10,000)b (24)b
market value
«
a Exhaust rate of 2.3'Nm /s, temperature of 21°C, operation at 25 percent LEL.
Costs in parentheses indicate a net gain.
References
1. "Identification and Control of the Hydrocarbon Emissions from Rubber
Processing Operations", EPA guideline document in preparation to be
released in 1977.
2. "Assessment of Industrial Hazardous Waste Practices, Rubber and Plastics
Industry", Chapter III, Rubber Products, Contract 68-02-3194,
Foster D. Snell.
3. "Source Assessment Document" No. 24 Rubber Processing, EPA Source
Assessment Document in preparation to be released in 1977.
56
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RUBBER TIRE INDUSTRY
Part 2 - FABRIC AND WIRE DIP AND CEMENT
Process Description
Tire manufacturers dip textiles, cord, and wire into rubber cement
or latex dip before calendering with rubber. In this process, sheets
of textiles, cord, and wire are fed under controlled tension to a cement
or latex dip tank. After dipping, the material is fed past a series of
vacuum lines or rotating beater boxes to remove excess rubber or latex.
The coated material passes through a drying oven to remove almost all
the solvent. There is a trend to perform this operation at the textile
mills rather than the tire manufacturing plant.
Base Line Emissions
The emission factor for textile, cord, or stranded wire cementing
or latex dipping is 100 grams per tire. Since 250,000,000 tires are
presently produced annually in this country, these emissions amount to
25,000 metric tons per year. Fabric dipping or cementing is used on
other segments of the rubber industry such as the manufacturing of
braided hose, braided belts, and rubber footwear. The emission factor
for cementing or dipping in these industries is 25 grams per kilogram
of product produced.
Control Technology
Incineration and carbon adsorption can be.employed to control
volatile organic emissions from textile and stranded wire cementing
or dipping operations. Thermal incineration can reduce the volatile
57
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organic emissions by 95 percent. Catalytic incinerators can reduce
the volatile organic emissions by 90 percent. Carbon adsorption can
reduce volatile organic emissions by 90 percent. It has not been feasible
to replace organic-borne with water-borne or high-solids materials.
Space may be a problem since half of the tire manufacturing plants
are housed in older buildings with little available vertical space
between floor and ceiling.
Cost of Control
Cost calculations for incineration and carbon adsorption are shown
in Tables 1 and 2.
References
1. "Identification and Control of Hydrocarbon Emissions from
Rubber Processing Operations." EPA guideline document in preparation
to be released in 1977.
2. "Assessment of Industrial Hazardous Waste Practices, Rubber
and Plastics Industry." Foster D. Snell, Inc. Florham Park, New Jersey.
February 1976.
3. "Source Assessment Document - Rubber Processing." Monsanto
Research Corporation. Dayton, Ohio. August 1975. (Draft Document).
58
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Table 1. : INCINERAr'T'^J COSTS FOR A TYPICAL
FABRIC CCMENTTNG OPERATION1"*
Incineration device
Ho !>ent rocovory
Thermal
Catalytic
Primary heat recovery
Themal
Catalytic
Primary and secondary heat recovery
Thermal
Catalytic
Capital
cost, $
100,000
' 105,000
20,000
120,000
145,000
140,000
Annual ized
operating
cost ,
$/year
50,000
50,000
35,000
35, -000
28,000^
30,000
Control cost,
$/ton of
hydrocarbons
removed
90
90
63
63
$
aExhaust rate of 2.3 Nm /s, temperature of 160°C, operation at 25 percent
.of the LEL.
Assumes that heat is recovered and used.
Table 2. CARBON ADSORPTION COSTS FOR A TYPICAL
FABRIC CEMENTING OPERATION0"
se with no credit for recovered
solvent
sc with recovered solvent
credited at fuel value
se with solvent credited at
market value
Capital
cost, $
180,000
180,000
180,000
Annual ized •
operating
cost ,
$/year
65,000
38,000
(9,COO)h.
Centre] • cost,
S/ton of
hydrocarbons
removed
160 .
90
(23)b
aExhaust rate of 2.3 Nm /s, temperature of 80°C, operation at 25 percent
.of the LEL.
Costs in parentheses indicate a net gain.
59
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RUBBER TIRE INDUSTRY
Part 3 - GREEN TIRE SPRAYING
Process Description
Before molding and curing, a "green" (nonvulcanized) tire is sprayed
both inside and out with organic solvent-borne release agents (a material
that prevents sticking to the vulcanizing mold). The solvent evaporates
in the spray and vulcanizing areas.
Base Line Emissions
Emissions due to green tire spraying are estimated at 140 grams per
tire. Since 250,000,000 tires are produced annually in this country,
these emissions amount to 35,000 metric tons of VOC each year.
Control Technology
Emissions would be 90 percent reduced by the substitution of water-
borne for organic solvent-borne materials for both the inside and outside
spray for green tire application. Water-borne materials have been used
by several plants but are not in widespread use.
There are no technological impediments to the replacement of organic
solvent-borne release agents with water-borne materials.
Adsorption is a feasible option but would likely be higher in cost
than use of water-borne materials. Adsorption has not been used for this
process.
Cost of Control
The switch from organic solvent-borne to water-borne material will
not require significant capital investment. Most of the same equipment
60
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usually can be, employed. Although the spray parameters are changed, the
cost of the water-borne material is less. There are no known factors
limiting control technology application.
References
1. "Identification and Control of the Hydrocarbon Emissions from Rubber
Processing Operations", EPA guideline document in preparation to be
released in 1977.
2. "Assessment of Industrial Hazardous Waste Practices, Rubber and
Plastics Industry", Chapter III, Rubber Products, under EPA Contract
68-02-3194, by Foster D. Snell.
3. "Source Assessment Document - Rubber". EPA source assessment
document in preparation to be released in 1977.
61
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ADHESIVES
Process Description
Adhesives are used for joining surfaces in assembly and construction
of a large variety of products. Adhesives allow faster assembly speeds,
less labor input, and more ability to join dissimilar materials than
other fastening methods. Adhesives may be water-borne, organic soWent-
borne, hot melt or high-solids.
Base Line Emissions
Organic solvent usage for various adhesive applications are given
below:
Organic Solvent -,
Application (metric tons/year)
Flooring, tile, wall covering 11,000
Other construction 14,000
Aircraft assembly 900
Automobile assembly 20,000
Plywood and veneer 2,000
Particle Board 1,300
Furniture assembly 7,300
Other wood products 11,800
Textile products 2,000
Footwear 7,300
Pressure sensitive tapes and labels 263,000
Gummed tapes and labels . 5^700
Packaging laminates 5,800
Other paper products 14,000
Glass insulation 13,000
Abrasive products 5,900
Printing and publishing 6,300
Rubber Products 21,500
Tires 1,000
Other 67,600
Total496,800
62
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Essentially all of the organic solvent used in these adhesive
applications is emitted to the atmosphere when the adhesive dries.
Control Technology
Organic solvent-borne adhesives can, in many instances, be replaced
with water-borne adhesives, hot melt adhesives, sol vent!ess two com-
ponent adhesives, or radiation cured adhesives. Organic solvent
reduction of 80 to 99 percent per job can be achieved by such replacement.
Water-borne natural adhesives (including animal glue, starches, dextrin
and proteins) already account for over 50 percent of the total adhesive
2
volume and have been in use for a long time. Synthetic water-borne
adhesives recently have been developed which have properties comparable
to organic solvent-borne adhesives. These water-borne synthetic adhesives
can replace organic solvent-borne adhesives for many applications.
Cost of Control
Low solvent adhesive may be lower or higher in cost,depending on the
product. In any case, the adhesive is only a small part of the cost of
the manufactured product and does not substantially affect product cost.
References
1. "Adhesives", Predicaste, Inc., 137, May 29, 1975.
2. "Synthetic Adhesives", Connolly, Eleanor, Stanford Research Institute,
1967.
63
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LARGE APPLIANCES
Process Description
Large appliance parts typically are stamped from metal sheets,
cleaned, and pretreated. Exterior parts are coated with a prime
coating by flow or spray coating techniques. Interior parts are
coated by flow or dip coating techniques. (Sometimes the prime
and interior part coatings are the same.) After curing, interior
parts are ready for assembly, and exterior parts are moved to the
topcoat application area. The topcoat is applied by automatic
electrostatic spraying and manual air spraying for touchup and
shading. After curing, the parts are assembled.
Base Line Emissions
Base line emissions for 1973 were about 32,300 metric tons per
year uncontrolled.
Control Technology
Table 1 shows the VOC reductions possible with applicable control
technology. Powder and electrodeposition provide the greatest reduction
of organic emissions but may involve extensive equipment changes.
Although water-borne and high-solids coatings do not provide as great
a reduction in emissions (60 to 90 percent), they usually may be
applied using existing coating application equipment. Add-on control
technology (incinerators and adsorbers) may be difficult to install due
to the multi-level structure and limited floor space in some existing
plants.
64
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Cost of Control :
If new coating application equipment is necessary, capital costs
for converting to low-solvent coatings may be appreciable. However,
reduced solvent and energy and labor requirements may lower operating
costs. Add-on control technology may be the most costly control method
p
($450-$650 per metric ton of organics removed for incinerators for
3
control of ovens and about $1100 per metric ton of organics removed
for carbon adsorbers for control of application and flashoff areas).
Energy Requirements
Incineration may require additional energy since ovens are often
located on the top level of the plant while the processes that can use
the recovered heat are often located at ground level.
References
1. "Sources and Consumption of Chemical Raw Materials in Paints
and Coatings - By Type and End Use," Stanford Research Institute,
October 197.4, page 210.
2. Combustion Engineering, Inc., Wellsville, New York, "Report on
Fuel Requirements, Capital Costs, and Operating Expense for Catalytic
and Thermal Afterburners," prepared for the U. S. Environmental Protection
Agency under Contract No. 68-02-1473, Task 13, EPA-450/3-76-031,
September 1976.
3. "Control of Volatile Organic Emissions from Existing Stationary
Sources - Volume I: Control Methods for Surface Coating Operations,"
EPA-450/2-76-028, November 1976 (OAQPS No. 1.2-067).
65
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Table 1
Control Technology for Large Appliance Coating
VOC Emissions,
Application
Primer
Application:
Interior Part
Single Coat
Application:
Topcoat
Application:
Control
Technology
Water- Borne
Electrodeposition
Water- Borne
Electrodeposition
Powder
Water-Borne
"Higher" Solids
Powder
Has Been Used
In Large
Appliance Plant?
yes
yes
yes
yes
yes
yes
yes
yes
Major
Equipment
Change
Necessary?
no
yes
no
yes
yes
no
no
yes
kilograms per
liter of coat-
ing (minus
water)
0.29b
0.02
0.29b
0.02
0.02
0.29b
0.44C
0.02
Percent
Reductic
80b
99
80b
99
99
80b
57C
99
All Applications:
Coating Area
and Flashoff
Tunnel:
Oven:
Carbon
Adsorber
Incinerator
no
yes
no
no
0.29
81
a The base case assumed that the previous organic solvent-borne coatings
contain 30 volume percent solids.
The water-borne coating is assumed to contain 30 volume percent solids,
14 volume percent organic solvent, and 56 volume percent water. This
is equivalent to the 80/20 Rule 66 definition of a water-borne coating.
c This is equivalent to about 45-50 volume solids coating presently
applied. Research is currently being done to apply high-solids (70-80
volume percent)coatings. Such application techniques should be
available in the near future.
Although no change in coating equipment is necessary, perhaps other plant
modifications will be necessary in large appliance plants to install
such equipment.
66
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MAGNET WIRE COATING
Process Description
Wire coating is the process of insulating electrical wire by applying
insulation varnish or enamel. Coated wire is used in a variety of
electrical machinery such as motors and transformers.
During coating, the wire is unwound from a spool and passed through
a bath of coating. The wire is then drawn through an orifice or die which
scrapes off excess coating, leaving a layer of predetermined thickness.
The wire is conveyed through an oven (around 800°F) where the solvent is
driven off and the coating cured.
Base Line Emissions
Annual solvent use for wire coating is 29,500 metric tons per year.
There is a high degree of control already in the industry, especially on
newer coating lines. Estimates of current solvent emissions are 8,000
metric tons per year.
Control Technology
Incineration, the only control technology commonly used, achieves
2 3
90 - 95 percent control and may be thermal or catalytic. * M6st newer
wire coating ovens are built with an internal catalytic incinerator which
burns solvents inside the oven. Control is common because recovered heat
can be .used, and because it eliminates malodors and avoids the buildup of
flammable resins in the stack. Some newer types of coatings
67
-------
will poison catalysts. If coatings that poison catalysts are used,
thermal incinerators are required.
Powder coatings and water-borne coatings have been developed for
only a small number of wire products to date.
Cost of Control
A typical wire coating oven with an internal catalyst costs $100,000 to
$200,000. The catalytic bed represents about $20,000 of the total.
For internal incinerators, ten or more ovens are frequently vented
4
to one incinerator. Costs for such an incinerator are given in Table 1.
TABLE 1 INCINERATION COST FOR WIRE COATING
(7 NnT/s, 290°C, 15% of LEL)
Type of
Incineration
Installed
Cost$
Annuali zed
Operating
Cost, $/yr
Cost Effectiveness
$/metric ton
of Solvent Removed
Non Catalytic 183,000
Primary and
Secondary Heat
Recovery
Catalytic 220,000
Secondary Heat
Recovery
34,800
39,690
48
55
68
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References
1. "Sources and Consumption of Chemical Raw Materials in Paints and
Coatings - By Type and End Use", Stanford Research Institute,
October 1974, page 210.
2. Ruff, R.J., "Catalytic Combustion in Wire Enameling", Wire,
October 1951, pages 936-940.
3. KJoppenburg, W.B., DeBell and Richardson Trip Report No. 106,
April 6, 1976.
4. Combustion Engineering, Inc., Wellsville, N.Y.,"Report of Fuel
Requirements, Capital Cost and Operating Expense for Catalytic and
Thermal Afterburners". Prepared for the U.S. Environmental Protection
Agency, Research Triangle Park, N.C. under Contract No. 68-02-1473,
(Task No. 13), Publication No. 450/3076/031.
69
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FLAT WOOD PRODUCTS
Process Description
Flat wood products include plywood, particle board, hardboard, cedar
siding, and Softwood molding. Not all such products are factory coated.
When they are factory coated, VOC emissions occur from: reverse-roll-
coating of filler; direct roll-coating of sealer; direct roll-coating of
topcoats; curtain coating; printing of wood-grain patterns and drying in
an infrared or steam-heated oven after one or more of the above coating
operations.
Base Line Emissions
At present, approximately 54,000 metric tons of VOC are emitted
yearly by sources in this category.
Control Technology
The control technology available for flat wood products includes
low-solvent ultraviolet (UV) curable coatings, water-borne coatings,
2
and incinerators. UV curable coatings are sensitive to UV radiation,
under which rapid polymerization takes place to form the coating film.
UV fillers are frequently employed but only a few lines use UV cured
topcoats. UV curable inks> from the paper coating industry would seem
to be applicable for grain printing as well. Opaque base coats
curable with UV radiation are not now available though they are expected
to be available soon. Where UV coatings are applicable, they produce
70
-------
essentially zero VOC emissions. Use of water-borne coatings usually
results in about an 80 percent VOC emission reduction. Water-borne
coatings are available for filling and base coating but few water-
borne graining inks or topcoats are marketed.
Afterburners can be used to control VOC emissions from baking ovens
2
with control efficiencies of greater than 90 percent. Although no
flatboard coating facility is now known to use carbon adsorption as
an air pollution control device, it is technically feasible.
Limitations to the use of UV coatings are lack of suitable opaque
basecoats and the difficulties associated with curing irregular shapes.
Water-borne coatings have problems with "blocking" (i.e., the sticking
of the paper sheets used to separate boards), poor adhesion or staining.
Also, high gloss water-borne topcoats are not generally available at
present.
Cost of Control
Accurate cost estimates are not yet available, but there probably
would be increased costs associated with water-borne coatings. First,
the coatings themselves may cost more. Also, there may be higher main-
tenance and utility costs with these coatings. Utility costs for UV
curing are less than the costs for curing conventional coatings.
Environmental Considerations
UV cure coatings do not have any adverse impact on the environment.
Water-borne coatings may result in slightly increased cost for water
pollution control since clean-up residue is sewered.
71
-------
Energy Requirements
Energy requirements for UV curing are less than for conventional
curing. For water-borne coatings, energy requirements may be slightly
greater than for conventional coatings though some plants are able to
operate at the same fuel usage. At afterburner equipped plants, there
would seem to be ample opportunity to make use of recovered heat in
the baking oven.
References
1. "Sources and Consumption of Chemical Raw Materials in Paints
and Coatings - By Type and End Use," Stanford Research Institute,
October 1974, page 210.
2. Emission Test Reports from Metropolitan Office of Southern
California Air Pollution Control District, No. C-2133, C-2292.
72
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INDUSTRIAL SURFACE COATING
Process Description
There are many surface coating operations for which emission
limitations have not been recommended in specific EPA guidelines
(Control Technology Documents) or Standards Support and Environmental
Impact Statements. While each product has to meet usage and possibly
substrate specifications which may be unique, nevertheless, generali-
zations can be made as to the applicability of the low solvent coatings,
i.e. powder, water-borne and high solids coatings. These coatings are
adaptable to many metal and plastic products. Particularly where the
coating is hand sprayed or air dried, low solvent coating may represent
the most cost effective means of VOC control.
Base Line Emissions
Base line emissions are shown below.
Solvents Used -|
Industry (metric tons per year)
Transportation equipment (other 15,400
than auto and light trucks)
Marine equipment 27,300
Factory finished building products 6,800
(other than flat wood products)
Exterior industrial maintenance 68,600
Interior industrial maintenance 38,600
Other products finishes 84,100
Thinners used 114,500
Total 335,300
Control Technology
Metal and plastic can be coated with enamels or other coatings con-
taining at least 33 percent feollds by volume. With average percent solids
73
-------
now around 20 percent, there will be about a 50 percent emission reduction
achieved by going to the higher solids coating. Coating with 33 percent
solids have already been used in many products, so no new technology should
be involved for most industries to use this technology. The coatings are
also applicable to wood products with opaque coatings.
The 33 percent solids coatings are not feasible for wood furniture and
other wood products with clear coatings which show the wood grain. Neither
do they apply to "trade sales", that is shelf goods or stock type coatings
sold through retail or wholesale outlets to jobbers, dealers, painters,
contractors, builders, automobile refinishers, or jobbers for maintenance of
residences, institutions, and office buildings. These types of coatings
can't usually be employed in industrial maintenance finishes which are
specifically formulated for a particular performance requirement in the
industrial environment.
There are many small metal products that are coated in only a few
colors. Such products include lawn and garden machinery, light fixtures,
bicycles, tools, playground equipment, small parts, metal furniture, and
innumerable other fabricated metal products. These products usually can
be primed by electrodeposition (EDP) and topcoated with powder coatings,
resulting in significantly less volatile organic compound (VOC) emissions.
EDP and powder coatings have been used by numerous sources in these
industries for both new and retrofit installations. Organic solvent emissions
when using these coating technologies are almost zero, so efficiency of
control approaches 100 percent. A realistic number limit is 0.04 kilogram
of VOC per liter of coating used. Water-borne dip and spray and high-solids
74
-------
coatings also are applicable to these sources but emission are greater,
about 0.37 kilograms per liter of coating used. This is an 80-90
percent VOC reduction over typical organic solvent-borne coatings. If
EDP or powder cannot be used, the latter should be evaluated. The key
factor governing applicability is whether the product meets normal use
specifications when coated with powder or by EDP. This is not usually
a problem since EDP and powder almost always give superior finish. Many
colors, frequent color change, large size,or the presence of heat-
sensitive materials may affect the feasibility of these options.
Cost of Control
The cost for metal coaters to switch to 33 percent solids enamels
usually is not great. There should be no development costs since such
coatings are already marketed. Conventional application techniques and
equipment frequently can be used but some capital investment may be necessary.
References
1. Stanford Research Institute, "Sources and Consumption of Chemical
Raw Materials in Paints and Coatings - By Type and End Use",
October 1974, page 210.
75
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