EPA-450/2-77-022
                 November 1977
                 (OAQPS NO. 1.2-079)
                                    OAQPS GUIDELINES
                         CONTROL OF VOLATILE
                             ORGANIC EMISSIONS
                                              FROM
                     SOLVENT METAL CLEANING
                  U.S. ENVIRONMENTAL PROTECTION AGENCY
                      Office of Air and Waste Management
                    Office of Air Quality Planning and Standards
                   Research Triangle Park, North Carolina 27711
I

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                         EPA-450/2-77-022
  CONTROL OF VOLATILE
    ORGANIC EMISSIONS
              FROM
SOLVENT METAL CLEANING
       Emissions Standards and Engineering Division
          Chemical and Petroleum Branch
      L S. ENVIRONMENTAL PROTECTION AGENCY
         Office of Air and Waste Management
       Office of Air Quality Planning and Standards
       Research Triangle Park. North Carolina 27711
               No\ember 1977

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This report is issued by the Environmental Protection Agency to report
technical data of interest to a limited number of readers.  Copies are
available free of charge to Federal employees, current contractors and
grantees,  and nonprofit organizations - in limited quantities - from the
Library Services Office (MD-35) , Research Triangle Park, North Carolina
27711;  or,  for a fee, from the National Technical Information Service,
5285 Port Royal Road, Springfield, Virginia 22161.
                   Publication No.  EPA-450/2-77-022

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                                 PREFACE
     The purpose of this  document is  to  inform  regional,  State,  and local
air pollution control  agencies of the different techniques  available for
reducing organic emissions from solvent  metal  cleaning (degreasing).  Solvent
metal cleaning includes the use of equipment from any of three broad categories:
cold cleaners, open top vapor degreasers, and conveyorized degreasers.  All
of these employ organic solvents to remove soluble impurities from metal
surfaces.
     The diversity in designs and applications of degreasers make an emission
limit approach  inappropriate; rather, regulations based on equipment specifications
and  operating requirements are recommended.  Reasonably available control
technology  (RACT)  for  these sources entails implementation of operating
procedures  which minimize  solvent loss and  retrofit of applicable control devices.
Required control equipment can be  as  simple as  a manual  cover or as complex
as a carbon adsorption system, depending on the size  and design of  the
 degreaser.   Required  operating procedures  include  covering degreasing
 equipment whenever possible,  properly using  solvent  sprays,  reducing the  amount
 of solvent carried out of the unit on cleaned  work by various means, promptly
 repairing leaking  equipment,  and most importantly properly disposing of wastes
 containing volatile organics.  Not all  controls and  procedures  will be applicable
 to all degreasers, although in general  specific operating requirements and
 control devices will  be applicable to the majority of designs within each
 category of degreasers.   Control  of  open  top and  conveyorized vapor
 degreasing is  the most  cost  effective,  followed by waste  solvent  disposal
 for all degreasing operations,  manufacturing  cold cleaning  and maintenance
  cold cleaning.
                                   m

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     Two levels of control for each type of degreaser have been identified
here as examples of reasonably available control  technology (RACT).  In general,
control level A shows proper operating practice and simple, inexpensive
control equipment.  Control level  B consists of level  A plus additional
requirements to improve the effectiveness of control.   The degree of
emission reduction for both individual items and control  levels are
discussed in the text.  Specific requirements can be modified to achieve
whatever level  of control is necessary.   Control  systems  for cold cleaners
are shown in Table 1, those for open top  vapor degreasers  in Table 2, and
those for conveyorized degreasers  in Table 3.
     Two exemptions are recommended.  First, conveyorized degreasers smaller
          2
than 2.0 m  of air/vapor interface should be exempt from  a requirement for
a major control device.  This would not  be cost effective and would tend to
move the small  conveyorized degreaser users to open top vapor degreasers
which emit more solvent per unit work load.  Second, open top vapor degreasers
                2
smaller than 1  m  of open area should be exempt from the  application of
refrigerated chillers or carbon adsorbers.  Again,  requirement for these
would not be cost effective.
                                   IV

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            TABLE 1-  CONTROL SYSTEMS FOR COLD CLEANING

Control System A
Control Equipment:
     1 .  Cover
     2.  Facility for draining cleaned parts
     3'  Permanent, conspicuous label, seizing the operating requirements
Operating Requirements:
           not dispose of waste solvent or transfer it to another party,
            £** Sffr^STA'S 5*3 <^="
     2.  Close degreaser cover whenever not handling parts in the cleaner.
     3.  Drain cleaned parts  for  at least  15 seconds or until dripping ceases.
 Control System B
 Control Equipment:
      1   Cover:  Same as in System A, except if W  "W,^1!^ "


 counterweight! nq or powered systems.)


 SM tf ^cft?^^^^™      ^t fit inlo tL cleaning
 system.
      3  Label:  Same as in  System A
                                      » '.
  excessive splashing.
       5   MOT control d.vie. for Mghly .ol.ttl. sol«nt,:  If tts so1«nt
  jf'fflia I: iJi't?«:"fcWi! 82 m." Ai£,"«2t5
  devices must be used:
       a.  Freeboard that gives a freeboard ratio*** >. 0.7
       b.  Mater cover (solvent must be insoluble in and heavier than water)
       c.  Other systems of equivalent control,  such as a refrigerated  chiller
  or carbon  adsorption.
  Operating  Requirempntt:
       Same  as in System A
                                                  d1vld"'
   width of the degreaser.

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    TABLE 2.  COMPLETE CONTROL SYSTEMS FOR OPEN TOP VAPOR DEGREASERS


Control System A

Control Equipment:

     1.  Cover that can be opened and closed  easily without  disturbing  the
vapor zone.

Operating Requirements:

     1.  Keep cover closed at all times except when processing  work  loads
through the degreaser.

     2.  Minimize solvent carry-out by the following measures:

     a.  Rack parts to allow full drainage.
     b.  Move parts in and out of the degreaser at less  than 3.3 m/sec  (11  ft/nrin).
     c.  Degrcase the work load in the vapor  zone at least 30 sec.  or until
condensation ceases.
     d.  Tip out any pools of solvent on the  cleaned parts before removal.
     e.  Allow parts to dry within the degreaser for at least 15 sec. or until
visually dry.
     3.  Do not degrease porous or absorbent  materials,  such as cloth,  leather,
wood or rope.

     4.  Work loads should not occupy more than half of  the  degreaser's open
top area.

     5.  The vapor level should not drop more than 10 cm (4  in) when the
work load enters the vapor zone.

     6.  Never spray above the vapor level.

     7.  Repair solvent leaks immediately, or shutdown the degreaser.

     8,  Do not dispose of waste solvent or transfer it  to another party
such that greater than 20 percent of the waste (by weight) will
evaporate into the atmosphere.  Store waste solvent only in  closed containers.

     9.  Exhaust ventilation should not exceed 20 m /min per m   (65  cfm per ft2)
of degreaser open area, unless necessary to meet OSHA requirements.   Ventilation
fans should not be used near the degreaser opening.

    10.  Water should not be visually detectable in solvent  exiting  the water
separator.

Control System B

Control Equipment:

     1.  Cover Csame as in system A}.

     2.  Safety switches

     a.  Condenser flow svrftcPi and thermostat - Csfiuts off sump neat if condenser
coolant is either not circulating or too warm).
     b.  Spray safety switch -  (shuts off spray pump if the vapor level drops
excessively, about 10 cm (4 in).

     3.  Major Control Device:

     Either:  a.  Freeboard ratio greater than or equal  to 0.75, and if the
degreaser opening is > 1 m  (10 ft'), the cover must be powered,
              b.  Refrigerated chiller,
              c.  Enclosed design (cover or door opens only when the dry part
is actually entering or exiting the degreaser.),                   ,          „
          2   d.  Carbon adsorption system, with ventilation >_ 15 m /min per m
(50 cfm/ft  ) of air/vapor area  (when cover is open), and exhausting <25 ppm
solvent averaged over one complete adsorption cycle, or
              e.  Control system, demonstrated to have control  efficiency,
equivalent  to or better than  any of the above.

     4.   Permanent, conspicuous label, summarizing operating procedures #1  to #6.

Operating Requirements:

     Same as  in System A

                                 vi

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        TABLE 3.   CONTROL SYSTEMS FOR CONVEYORIZEO DEGREASERS

Control System A
Control Equipment:  None
Operating  Requirements:                                     2              ,
., .e
fins should not be  used near the degreaser opening.
     2.  Minimize carry-out emissions by:
     :-.  ssaaisr-i5=» S^SKJ
     3  Do not dispose of waste solvent or  transfer It to another party such
 ss
      4.   Repair solvent leaks  inmediately, or shutdown the degreaser.
      5.   Water should not be visibly detectable in  the solvent exiting the
 water separator.
 Control  System B
 Control  Equipment:
      1.  Major  control  devices; the degreaser must be controlled by either:
      a.  Refrigerated chiller,          upntiiation > 15 m2/min per m2 (50 cfm/ft2)
      b.  Carbon ^sorption  system  wthvent.lat    ij5^^'  <25 ppm of
                                                                    or
  than either of the above.
  or vapor.
       3.  Safety switches
       a   Condenser flow switch and thermostat - Cshuts off  sump heat if
   C°01T ^raylafS   S^Si."     P-P " Conveyor if the vapor
                                                 off sump heat when vapor
   level  rises too high).
   of the opening.
        5 '  Down-time covers:  Covers  should be provided for closing off  the
   entrance and exit during shutdown hours.
   Operating Requirements:
         1  to 5 .  Same  as  for System A
    and removed just before they are
                                 vn

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                             TABLE OF CONTENTS

                                                                          Page
Preface	-Hi
Chapter 1.0  Introduction and Summary 	 1_1
        1.1  Need to Regulate Solvent Metal  Cleaning  	 1-1
        1.2  Regulatory Approach  	 1-2
Chapter 2.0  Sources and Types of Emissions  	 2-1
        2.1  Industry Description 	 2-1
        2.2  Types of Degreasers and Their Emissions  	 2-4
             2.2.1  Cold Cleaners	2-7
                    2.2.1.1   Design and Operation 	 2-7
                    2.2.1.2   Emissions  	 2-12
             2.2.2  Open Top Vapor Degreasers	2-16
                    2.2.2.1   Design and Operation 	 2-16
                    2.2.2.2   Emissions  	 2-25
             2.2.3  Conveyorized Degreasing  	 2-33
                    2.2.3.1   Design and Operation 	 2-33
                    2.2.3.2   Emissions  	 2-39
        2.4  References	2-45
Chapter 3.0  Emission Control Technology  	 3-1
       - 3.1  Emission Control Devices   	 3-1
             3.1.1  Emission Control Devices  	 3-1
                    3.1.1.1   Improved Cover 	 3-2
                    3.1.1.2   High Freeboard 	 3-5
                                    vm

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                                                                         Page


                  3.1.1.3  Refrigerated Chillers 	  3"6

                                                                         3-9
                  3.1.1.4  Carbon Adsorption   	

                                                                         3-14
                  3.1.1.5  Safety Switches 	

                                                                         o -I c

           3.1.2' Controls to Minimize Carry-Out 	


           3 l 3  Controls for Both Solvent Bath and                     3_18

                  Carry-Out Emissions  Combined   	


                  3.1.3.1  Automated Cover-Conveyor System  	 3-18

                                                                         o 20
                  3.1.3.2 Refrigeration  Condensation   	


            3.1.4 Control of  Waste Solvent Evaporation 	 3'22


                   3.1.4.1  Current Practices 	  3'22


                   3.1.4.2  Recommended Practices 	  3"2

                                                                          3-27
            3.1.5  Other Control  Devices   	

                                                                          •3 OQ
                   3.1.5.1  Incineration   	

                                                                          o oft
                   3.1.5.2  Liquid Absorption 	

                                                                          3-29
        3.2  Complete Control  Systems   	

                                                                          3-30
            3.2.1  Cold  Cleaning  Control  Systems   	 °


            3.2.2 Control Systems for Open Top Vapor                     3_32

                   Degreasing 	


            3.2.3 Control  Systems for Conveyorized  Degreasers   	 3-32


                                                               	3-37
        3.3 References  	

                                                               	4-1
Chapter 4.0  Cost Analysis 	

                                                               	4-1
        4.1  Introduction  	

                                                               	4-1
             4.1.1  Purpose   	

                                                               	4-1
             4.1.2  Scope 	

                                                                           4-2
             4.1.3  Model  Plants  	


             4.1.4  Capital Cost Estimates	4"

                                                                           4-3
              4.1.5  Annualized Costs  	
                                   IX

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                                                                           Page
        4.2  Cold Cleaners	4-4
             4.E.I   Model  Plant Parameters	4-4      |
             4.2.2  Control  Costs	4-6
        4.3  Open Top Vapor Degreasers	4-8
             4.3.1   Model  Plant Parameters 	 4-8
             4.3.2  Control  Costs	4-8
             4.3.3  Cost Effectiveness	 ... 4-14
        4.4  Conveyorized  Degreasers 	  	 4-16
             4.4.1   Model  Plant Parameters 	 4-16
             4.4.2  Control  Costs	4-18
             4.4.3  Cost Effectiveness	4-20
        4.5  References	4-24
Chapter 5.0  Adverse Environmental  Effects of Applying
             The Technology  	 5-1
        5.1  Air Impacts	5-1      ^
        5.2  Water Impacts	5-1
             5.2.1   Waste Solvent Disposal	5-1
             5.2.2  Steam Condensate from Carbon Adsorption  	 5-2
                    5.2.2.1   Chlorinated Solvent in Steam
                             Condensate	5-2
                    5.2.2.2  Stabilizers in Steam Condensate 	 5-3
             5.2.3  Effluents from Water Separators  	 5-4
        5.3  Solid Waste Impact  	 5-4
        5.4  Energy Impact	5-5
        5.5  Other Environmental Concerns  	 5-6
        5.6  References	5-8
Chapter 6.0  Compliance Testing Methods and Monitoring
             Techniques	6-1

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       6 1  Observation of Control Equipment and
            Operating  Practices  	
                                                                        fi—?
       6.2  Material Balance   	
                                                                        6-3
       6.3  Other Emission Tests  	
Chapter 7.0   Enforcement Aspects  	
                                                                        7-2
       7.1   Regulatory Approaches 	
             7.1.1  Emission Standards 	 7"2
             7.1.2  Equipment Standards  	 7~3
             7.1.3  Operational  Standards  	  7"4
             7.1.4  Solvent Exemption Standards  	
        7.2  Affected  Facilities - Priorities   	  7"5
             7.2.1  Definitions  of Affected Facilities  	  7'5
             7.2.2 Priorities of Enforcement   	
 Appendix A.O   Emission Test  Results
 Appendix  B.O   Calculations
                                   XI

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                               LIST OF TABLES
                                                                          Page       I
 Table 1   Control Systems for Cold Cleaning	v
 Table 2   Control Systems for Open Top Vapor Degreasers	vi
 Table 3   Control Systems for Conveyorized Degreasers  	  vii
Table 2-1  Common Metal Cleaning Solvents  	 2-3
Table 2-2  National Degreasfng Solvent Consumption (.1974)	2-5
Table 2-3  Emissions from Solvent Degreasers (1974) 	 2-6
Table 3-1  Control Systems for Cold Cleaning	3-31
Table 3-2  Complete Control Systems for Open Top Vapor Degreasers .... 3-33
Table 3-3  Control Systems for Conveyortzed Degreasers  	 3-35
Table 4-1  Cost Parameters for Model Cold Cleaners  	 4-5
Table 4-2  Control Costs for Typical Cold Cleaners  	 4-7
Table 4-3  Cost Parameters for Model Open Top Vapor Degreasers	4-9
Table 4-4  Control Cost for Typical Stze Open Top 1/apor Degreaser .... 4-10       M
Table 4-5  Control Cost for Small Open Top 'Vapor Degreaser	4-11
Table 4-6  Cost Parameters for Model Conyeyorfzed Degreasers	4-17
Table 4-7  Control Costs for Typical Conveyorized Degreasers  	 4-19
                                   xn

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                             LIST Of FIGURES
                                                                         Page
Figure 2-1  Cold Cleaner	2~9
Figure 2-2  Cold Cleaner Emission Points 	  2~13
Figure 2-3  Open Top Vapor Degreaser	2-18
Figure 2-4  Basic Principle for Water Separator for Vapor Degreaser  . .  2-20
Figure 2-5  Open Top Degreaser with Offset Condenser Coils 	  2-21
Figure 2-6  Two Compartment Degreaser with Offset Boiling Chamber  . . .  2-22
Figure 2-7  Two Compartment Degreaser   	  z~23
Figure 2-8  Degreaser with Lip Exhaust  	  2'24
Figure 2-9  Open Top Vapor Degreaser Emission Points  	  2~26
Figure 2-10 Cross Rod Conveyorized Degreaser  	 2~35
Figure 2-11 Monorail Conveyorized Degreaser   	 2-36
Figure 2-12 Vibra Degreaser   	 Z"37
                                                                         7  *3Q
Figure 2-13 Ferris  Wheel  Degreaser  	 c"°°
Figure 2-14 Mesh Belt  Conveyorized  Degreaser  	 2-40
 Figure 2-15 Conveyorized Degreaser  Emission Points 	 2~42
 Figure  3-1  Refrigerated Freeboard  Chiller 	 3~7
 Figure  3-2  Carbon  Adsorber  	 3"10
 Figure  3-3  Adsorption Cycle 	 3"11
 Figure 3-4  Desorption Cycle 	 3"12
 Figure 3-5  Elevator Design of Degreaser - Vapor Type  	 3-19
 Figure 3-6  Vapor Pressures of Several Solvents  	  3~21
 Figure 3-7 -External Still 	  3"25
 Figure 4-1  Cost-Effectiveness of Alternative Control Options for
             Existing Open Top Vapor Degreasers  	 ^-'3
 Figure 4-2  Cost-Effectiveness of Alternative Control Options for
             Existing Monorail Degreasers	^'
 Figure 4-3  Cost-Effectiveness  of Alternative Control Options for
             Existing  Cross-Rod  Degreasers	4""
                                   xm

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                      1.0   INTRODUCTION AND SUMMARY

     The purpose of EPA's series of control  technique guideline documents
is to provide guidance on emission reduction techniques which can be applied
to existing sources in specific industries.   The documents are to be used to
assist States fn revising their implementation plans (SIP's) to attain and
Tnafntain National Ambient Air Quality Standards (NAAQS).  This document discusses
volatile organic compound (VOC) emissions and applicable control techniques
for organic solvent metal cleaning operations (degreasing with solvents).

1.1  NEED TO  REGULATE SOLVENT METAL CLEANING
     Solvent  metal  cleaning  is  a  significant source  of volatile organic
compounds  (VOC)  and tends  to be concentrated in urban  areas where the
oxidant NAAQS is likely  to  be exceeded.   In  1975  solvent  metal  cleaning
emitted about 725 thousand metric tons  of organics.   This represents
 about four percent of the national organic  emissions from stationary
 sources.  Presently, solvent metal cleaning is the fifth largest stationary
 source of organic emissions.  Although emissions from solvent degreasing
 (i.e., metal cleaning) represent about four percent of nationwide VOC
 sources, the proportion is  significantly higher  in most  urban areas,
 because of their  high concentration of metalworking  industries.  For example,
                                    1-1

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the Southern California Air Quality Management District estimates that 14.8
percent of the stationary organic emissions in Los Angeles County are               4
attributable to solvent degreasing.
     Control technology is available to reduce hydrocarbon emissions from
existing solvent metal cleaning operations.  However, this technology has
not been broadly applied largely because of unawareness of economic
incentives and the absence of regulatory requirements.  In 1974, for example,
16 states covered degreasing operations with solvent regulations identical
or similar to Rule 66 of the Los Angeles County Air Pollution Control District.
Since then, additional state and local agencies have adopted the same types of
statutes.  Generally, up to 3,000 pounds of VOC emissions per day are allowed
from sources using solvents considered non-photochemically reactive under
Rule 66 criteria.  Since solvent metal cleaning operations rarely release
more than that amount, they have usually complied with Rule 66 regulations
merely by substitution.  Regulatory incentive to institute control  technology       A
rather than substitution is necessary to achieve positive emission  reduction.
1.2  REGULATORY APPROACH
     Photochemical oxidant control  strategies in the past have relied heavily
on the substitution of solvents of  relatively low photochemical  reactivity to reduce
emissions of higher reactivity VOC.  Thus,  total emissions did not  necessarily
decrease, only the make-up of those emissions changed.  One problem with this
approach was that many solvents classed as  low reactivity materials have since
been found to be moderately and in  some cases highly reactive.  EPA's current
direction and the direction of this document is toward positive reductions of
all VOC emissions.  This is not only more rational from a standpoint of
conservation but some low reactivity solvents are now suspected of  contributing
                                    1-2

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to upper atmospheric ozone depletion.   These reasons  and others  support the
decision to concentrate on positive reduction rather than substitution.
     Positive emission reduction from solvent metal cleaning should be
attained though use of proper operating practices and retrofit control
equipment.  Proper operating practices are those which minimize solvent
loss to the atmosphere.   These  include covering degreasing equipment
whenever  possible,  proper use of  solvent  sprays, various means of  reducing
the amount of solvent carried out of  the  degreaser on  cleaned work, prompt
 repair of leaking equipment,  and  most importantly, proper  disposal  of wastes
 containing volatile organic solvents.  In addition to  proper operating
 practices there are many control  devices  which can be  retrofit  to degreasers;
 however, because of the diversity in their designs, not all degreasers
 require all control devices.  Small degreasers using room temperature solvent
 may require only a cover, whereas a  large degreaser using boiling solvent
 may require  a  refrigerated freeboard chiller or a carbon adsorption  system.
 Two types of control  equipment which will  be applicable to many degreaser
  designs  are  drainage  facilities  for  cleaned parts and safety switches and
  thermostats  which  prevent large  emissions  due  to  equipment malfunction.  The
  many  degreaser designs  along with the emissions  characteristic of those
  designs  and the factors affecting those  emissions are described in Chapter 2.
  Control  devices for each type of emission and control systems  for each
  degreaser design are described in Chapter 3.
                                      1-3

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                    2.0   SOURCES  AND TYPES  OF  EMISSIONS

2.1  INDUSTRY DESCRIPTION
     Solvent metal cleaning describes  those processes using non-aqueous
solvents to clean and remove soils from metal  surfaces.   These solvents,
which are principally derived from petroleum,  include petroleum distillates,
chlorinated  hydrocarbons,  ketones, and alcohols.  Organic solvents such as
these can be  used alone  or in blends to remove water insoluble soils for
cleaning  purposes and to prepare parts for painting, plating, repair,
inspection,  assembly, heat treatment or machining.
      Solvent metal  cleaning is  usually chosen after experience has  indicated
 that satisfactory cleaning is  not obtained with  water or detergent  solutions.
 Availability, low cost and farniMarily combine to make water the first
 consideration for cleaning; however,  water has several  limitations  as a
 cleaning agent.  For example, it exhibits low solubility for many organic
 soils, a slow drying rate, electrical conductivity, a high surface tension
 and a  propensity for rusting ferrous metals  and  staining non-ferrous metals.
 All of these limitations can be overcome  with the  use of  organic solvents.
      A typical  industrial deceasing  solvent would be expected  to  dissolve
  oils,  greases,  waxes,  tars,  and in some  cases water.   Insoluble matter such
  as sand, metal  chips,  buffing  abrasives  or fibers, held by the  soils, are
  flushed away.
                                      2-1

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     A broad spectrum of organic solvents is available.   Choices among the
solvents are based on the solubility of the soil, toxicity, flammability,
evaporation rate, effect on non-metallic portions of the part cleaned and
numerous other properties.  The most important properties of solvents
commonly used in metal cleaning are summarized in Table  2-1.
     As would be expected, the metal working industry is the major user of
solvent metal cleaning.  Eight SIC codes (Numbers 25 and 33 to 39) cover
these industry categories.  Examples of industries within these classifications
are automotive, electronics, appliances, furniture, jewelry, plumbing,
aircraft, refrigeration, business machinery and fasteners.   All are frequent
users of organic solvents for metal cleaning.   However,  the use of solvents
for metal cleaning is not limited to these industries; solvent metal  cleaning
is also used in non-metal working industries such as printing, chemicals,
plastics, rubber, textiles, glass, paper and electric power.  Often,  the
function of the organic solvents in these industries is  to  provide maintenance
cleaning of electric motors, fork lift trucks, printing  presses,  etc.   Even in
non-manufacturing industries, solvent metal  cleaning is  commonplace.   Most
automotive, railroad, bus, aircraft, truck and electric  tool repair stations
use these solvents.   In short, most businesses perform solvent metal  cleaning,
at least part time,  if not regularly.  The number of companies routinely using
solvent metal  cleaning operations probably exceeds one million.   Furthermore,
large scale users may often have over 100 separate degreasing  operations at
one plant location.
     Solvent metal  cleaning is broken into three major categories:  cold
cleaning, open top vapor degreasing and conveyorized degreasing.   In  cold
cleaning operations, all  types of solvents are used depending  on  the  type
of parts to be cleaned.   Vapor degreasing uses halogenated  solvents because

                                   2-2

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                                                           Table  2-1

                                                  COMMON METAL CLEANING SOLVENTS****
Tvpe of Solvent/
               Solvent
Soils
           Toxicity  Flash  Evaporation  Solubility
                         t    Rate**      & wt.j —
Alcohols
               Ethanol  (95%)
               Isopropanol
               Methanol
 Aliphatic Hydrocarbons
                Heptane
                Kerosene
                Stoddard
                Mineral Spirits 66

 Aromatic Hydrocarbons
                Benzene***
              •  SC  150
vj               Toluene
'0               Turpentine
                Xylene

 Chlorinated Solvents           ,.4 *«,*•*
                Carbon Tetrachloride***
                Methylene Chloride
                Perchloroethylene
                 1,1,1-Trichloroethane
                Trichloroethylene

  Fluorinated Solvents
                 Trichlorotrifluoro-
                   ethane (FC-113)
  Ketones
                 Acetone
                 Methyl ethyl ketone
poor
poor
poor
                                            good
                                            good
                                            good
                                            good
                                             good
                                             good
                                             good
                                             good
                                             good
                                           excellent
                                           excellent
                                           excellent
                                           excellent
                                           excellent
                                             good
  good
  good
11
1000*
400*
200*
500*
500
200
200
10*
200
200*
100*
100*
10*
500*
100*
350*
100*
60°F
55°F
58"F
<20°F
149°F
105°F
107°F
10°F
151°F
45°F
91°F
81°F
none
none
none
none
none
24.7
19
45
26
0.63
2.2
1.5
132
0.48
17
2.9
4.7
111
363
16
103
62.4
              1000*
                                                          1000*
                                                           200*
                                                                  none
<0°F
28°F
                                                                            439
122
 45
                                             0.2
                                                                                          27
Boiling Point Pounds
(Ranqe) Per Gal,
165-176°F
179-181°F
147-1498F
201-207°P
354-525-F
313-380°F
318-382'F
176-177eF
370-410°F
230-232°F
314-327'F
281-2848F
170-172°F
104-105. 5°F
250-254-F
165-194eF
188-190°F
6.76
6.55
6.60
5.79
6.74
6.38
6.40
7.36
7.42
7.26
7.17
7.23
13.22
10.98
13.47
10.97
12.14
Price
Per GaLt
$ 1.59
$ 1.26
$ 1.11
$ 0.86
$ 0.66
$ 0.62
$ 0.62
$ 1.06
$ 0.90
$ 2.40
$ 0.96
$ 3.70
$ 2.83
$ 3.33
$ 2.78
$ 3.13
                                                                                                       117°F
132-134°F
174-176°F
                                                                                                                   13.16    $ 7.84
6.59
6.71
    •Federal Register, June 27, 1974, Vol  39^No.  125                beaker Qn an analytical balance (Dow Chemical Co




     (July 1, 1975).
                                                                                $  1.45
                                                                                $  1.74
                                                                             ethod)

-------
they are not flammable and their vapors are much heavier than air.
      The most recent estimates are that there are 1,300,000 cold
cleaning units in the United States, with about 70 percent of these
devoted to maintenance or servicing operations and the remainder used
for manufacturing operations.  There are also an estimated 22,000 open
top vapor degreasers and 4,000 conveyorized degreasers.   Of the estimated
726,000 metric tons per year of solvent used for degreasing, roughly 60
percent is for cold cleaning, 25 percent for open top vapor degreasing
and 15 percent for conveyorized degreasing.  Tables 2-2  and 2-3 summarize
the above information.  Emissions are discussed in detail  in the next
chapter.

2.2  TYPES OF DEGREASERS AND THEIR EMISSIONS
      There are three basic types of organic solvent degreasers:   cold
cleaners, open top vapor degreasers, and conveyorized degreasers.   Cold
cleaners are usually the simplest and least expensive.   Their solvent is
usually near room temperature, but is sometimes heated.   The temperature,
however, always remains below the solvent's boiling point.   A cold cleaner
is a tank of solvent usually including a cover for nonuse  periods.   Inside
is a work surface or basket suspended over the solvent.   An open  top vapor
degreaser resembles a large cold cleaner;  however, the solvent is  heated  to
its boiling point.  This creates a zone of solvent vapor that is  contained by
a set of cooling coils.   Both the cold cleaner and the open top vapor degreaser
clean individual  batches of parts; thus, they are termed "batch loaded".   A
conveyorized degreaser is loaded continuously by means of  various  types of conveyor
systems, and may either operate as a vapor degreaser as  a  cold cleaner.
                                     2-4

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       Solvent Type
                                      Table 2-2

                      National Degreasing  Solvent  Consumption*  (1974)
                                                            *^
                                    Solvent Consumption  (10  metric tons)

                                    cleaningVapor degreaslng
Halogenated:
  Trichloroethylene
  1,1,1 Trichloroethane
  Perchloroethylene
  Methylene Chloride
  Tri chl orotri f1uoroethane
 Aliphatics
 Aromatics:
   Benzene
   Toluene
   Xylene
   Cyclohexane
   Heavy Aromatics
                                   T53
                                    222
                                    7
                                   14
                                   12
                                    1
                                   12
                                   4T
                                                  "276
                                                                    legreaslng
25
82
13
23
10
128
80
41
7
20
153
162
54
30
30
~~429~
                                                                        222
   46
  Oxygenated:
    Ketones:
      Acetone
      Methyl  Ethyl  Ketone

    Alcohols:
      Butyl
    Ethers
                                    10
                                     8
                                                                          29
Total Solvents:
 Range of Accuracy:

                                  on the above estimates.

Delude!125,000 metric tone^from non boiling conyevorized degreasers.

  Includes 75,000 metric tons from conveyorized vapor degreasers.
 ***
                                             2-5

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Type Degreaser
                                Table 2-3

                 Emissions from Solvent Degreasers  (1974)
Estimated National
     Emission
    (103Mt/yr)
Approximate
No. of Units
 Nationally
Averaged Emission
  Rate per Unit
     (Mt/yr)
Cold Cleaners


Open Top Vapor
 Degreasers


Conveyorized
 Degreasers
      380'
      200
      100
 1,220,000


    21,000



     3,700
      0.3
      10
      27
*380 emission = 450 consumption (from Table 2-2) minus 25 for wiping losses,
25 for conveyorized cold cleaning and 20 for non-evaporative waste solvent
disposal  (incineration and non-evaporating landfill encapsulation).
                                   iJ-6

-------
2.2.1   Cold Cleaners
      Cold cleaner operations include spraying, brushing, flushing and
immersion.  The solvent occasionally is heated in cold cleaners but always
remains well below its boiling point.
      Cold cleaners are defined here not to include nonboiling conveyortzed
degreasers which are covered in Section 2.3.  Wipe cleaning is also not
included.
      Cold cleaners are estimated to result in the largest total emission
of the three categories of degreasers.  This is primarily because of the
extremely large number of these units (over 1 million nationally) and because
much of the disposed of waste solvent is allowed to evaporate.  It is
estimated that cold cleaners emit 380 thousand metric tons of organics per
year, this being  about 55 percent of the national degreasing emissions
(see Appendix B.I).  Cold cleaning solvents nationally account for almost
all of the aliphatic, aromatic, and oxygenated degreasing solvents and
about one-third of halogenated degreasing solvents.
      Despite the large aggregate emission, the average cold cleaning unit
generally emits only about one-third ton per year of organics, with about
one-half to three-fourths of that emission resulting from evaporation of
the waste solvent at a disposal site.
2.2.1.1  Design and Operation -
                                      2-7

-------
      Typical  Model  - A typical  cold  cleaner is  shown  in  Figure  2-2.   The
 dirty parts  are cleaned manually  by  spraying  and  by soaking  in  the  dip  tank.
 The solvent  in  the  dip tank  is  often agitated to  enhance  the cleaning action.
 After cleaning, the basket of cleaned parts may be suspended over the solvent
 to allow the  parts  to drain,  or the  cleaned parts may  be  drained on  an
 external  drainage rack (not  shown) which  routes the drained  solvent  back  into
 the cleaner.  The cover is intended  to be  closed whenever parts are  not being
 handled  in the  cleaner.  The  cold cleaner  described and shown in Figure 2-|
 is  most  often used  for maintenance cleaning of metal parts.  A typical size
 of such  a maintenance cold cleaner is about 0.4 m2 (4  ft2) of opening and
 about  0.1 m   (30 gallon) capacity.
     Applications -  The  two basic types of cold cleaners  are maintenance
 cleaners and manufacturing cleaners.  The maintenance  cold cleaners  are usually
 simpler, less expensive, and  smaller.  They are designed  principally  for
 automotive and  general plant maintenance cleaning.
     Manufacturing  cold  cleaners usually perform a higher quality of cleaning
 than do maintenance  cleaners and are thus more specialized.  Manufacturing
 cold cleaning is generally an integral stage in metalworking production.
 Manufacturing cold  cleaners are fewer in number than maintenance cleaners
 but tend to emit more solvent per unit because of the larger size and work
 load.  Manufacturing cleaners use a wide variety of solvents, whereas
maintenance cleaners use mainly petroleum solvents such as mineral  spirits
 (petroleum distillates, and Stoddard solvents).   Some  cold cleaners  can
serve both maintenance and manufacturing purposes  and  thus are difficult
to classify.
     The type of cold cleaner to be used for a particular application depends
on two main factors: (1) the  work  load and (2) the required cleaning

                                      2-8

-------
                             Figure ?-l



                            COLD CLEANER
Basket
Solvent
                                                                     Cleaner
                                                                      Pump
                                    2-9

-------
effectiveness.  Work load is a function of tank size, frequency of cleaning,
and type of parts.  Naturally, the larger work loads require larger degreasers.
The more frequently the cold cleaner is used, the greater the need to automate
and speed up the cleaning process; more efficient materials handling systems
help automate, while agitation speeds cleaning.  Finally, the type of parts
to be cleaned is important because more thorough cleaning and draining
techniques are necessitated for more complexly shaped parts.
     The required cleaning effectiveness establishes the choice of solvent
and the degree of agitation.  For greater cleaning effectiveness, more
powerful solvents and more vigorous agitation are used.   Generally, emissions
will increase with agitation and with higher solvency.
     Equipment Design - Although classifying cold cleaners according to
maintenance or manufacturing application is a convenient initial approach,
manufacturing cold cleaners vary so widely in design that no one typical
design can adequately describe them.  Thus, a more specific classification of
manufacturing cold cleaners must also consider the equipment design.  The
most important design factors are tank design, agitation technique, and the
material handling of parts to be cleaned.
     The two basic tank designs are the simple spray sink and the drip tank.
The simple spray sink is usually less expensive.  It is  more appropriate  for
cleaning applications that are not difficult and require only a relatively
low degree of cleanliness.  The dip tank provides more  thorough cleaning
through soaking of dirty parts.  Dip tanks also can employ agitation, which
improves cleaning efficiency.
     Agitation is generally accomplished through use of pumping, compressed
air, vertical motion  or ultrasonics.  In the pump agitated cold cleaner,
the solvent is rapidly circulated in the soaking tank.   Air agitation involves

                                    2-10

-------
dispersing compressed air fro. the bottom of the soaking tank; the air bubbles
providing a scrubbing action.  In the vertically agitated cold cleaner, dirty
parts move up and down while submerged in order to enhance the cleaning process.
Finally, in the ultrasonically agitated tank, the solvent is vibrated by high
frequency sound waves.  Ultrasonically agitated liquids often need to be heated
to  specific temperatures  to  achieve  optimum cavitation.  Cavitation  is the
implosion of  microscopic  vapor cavities within  the  liquid solvent.   The  implosions,
which are caused  by pressure differentials  of the sound waves in  the solvent,
 break down  the dirt film on  the  parts.
      The designs  for material handling in cold cleaning systems  are  almost
 endless, but they are generally divided into manual and batchloaded  conveyorized
 systems.  (Continuously loaded conveyorized systems are described separately in
 Section 2.3).  Manual loading is used for simple, small-scale cleaning operations
 and  is self  explanatory.  Batchloaded conveyorized systems are for  use in the
 rnore complex, larger-scale  cleaning operations.  These systems may  include an
 automated dip, which automatically  lowers,  pauses, and raises the work load.
 They may also include systems,  such as a roller  conveyor, to transfer the work
 load to  other operations.   In another variation,  two  or more dip  tanks may be
 used in  series.   These  tanks may contain increasingly pure solvent  in a "cascade--
 cleaning system.   The  consecutive dip  tanks may  also  contain different  cleaning
  solutions  for more complex  operations  and  may even be combined  with vapor
  cleaning and aqueous systems.
       The materials handling technique can  be important in reducing  emissions
  from cold cleaning.  Regardless of the system, the work loads need to be handled
  so  that the solvent has sufficient time to drain from the cleaned  parts into an
  appropriate container.  Drainage facilities are described in Section 3.1.2.
                                       2-11

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2.2.1.2  Emissions -
      Solvent evaporates both directly and indirectly from the  cold cleaners.
The emission rates vary widely;  nevertheless,  the average emission  rate,
calculated from national consumption data, is  estimated to be about 0.3
metric ton per year.  Maintenance and manufacturing cold cleaners are
estimated to emit approximately 0.25 and 0.5 metric tons per year, respectively
(see Appendix B.2.2).  Data from the Safety Kleen Corporation reports only
0.17 metric tons per year for thier cold cleaner.  However, their emissions
are expected to be lower than others because most of the waste solvent from
Safety Kleen units is distilled and recycled by the company.
      Emissions from a cold cleaner occur through:  (1) bath evaporation, (2)
solvent carry-out,  (3) agitation,  (4) waste solvent evaporation, and (5)
spray evaporation.  These are depicted in Figure 2-2 and discussed in the
following sections.
     Bath Evaporation - Bath evaporation can be greatly reduced through use of
a cover.   Generally, the cover should be closed whenever the parts  are not being
handled in the cold cleaner.  Although covers  are standard equipment on most
cold cleaners, keeping the cover closed requires conscientious effort on the part
of the operator and his suoervision.  As will  be discussed in Section 3.1.1, there
are various means of inducing the operator to  close the cover more frequently.
     Where solvents much more volatile than mineral spirits are used, adequate
freeboard height is important to reduce evaporation.   Freeboard height is the
distance from the solvent to the top edge of the cold cleaner.   The requirement
for freeboard height is most commonly expressed as freeboard ratio, with  freeboard
ratio being defined as the ratio of freeboard height to degreaser width (not
length).
     Excessive drafts in the workshop can significantly increase solvent bath
evaporation.  Thus, room and exhaust ventilation should be no greater than is
                                     2-12

-------
                              BATH/      ,
                             EVAPORATION    /
Figure 2-2.   COLD CLEANER EMISSION POINTS
                            2-13

-------
necessary to provide  safe levels  for  the  operator's  health  and plant's  protection.
     Agitation Emissions  - Agitation  increases  emissions.   The rate  of  emission
depends upon: (1)  use of  the cover,  (2) agitation  system  adjustments  and (3)  vola-
tility of the solvent.   If the cover  is kept closed  during  agitation, then emissions
usually are insignificant.  However,  agitation  emissions  can  increase dramatically
with the cover open.   This is especially  true with ultrasonic agitation of solvents
heated to their optimum cavitation temperature. The bath should also be agitated for
no longer than necessary to complete  the  cleaning.  Poor adjustment  of  the agitation
system may also increase emissions.   In  particular,  the air flow into air agitated
                                       3
cleaners should be about 0.01 to 0.03 m   per minute per square meter of opening.
     EPA tests on cold cleaners indicate  that the  volatility of  the  solvent greatly
affects emissions due to agitation.   Emissions  of  low volatility solvents increase
significantly with agitation; however, contrary to what one might expect, agitation
causes only  a small increase in emissions of high  volatility solvents.   This is
believed to  be due to the already high unagitated  evaporation rate of high volatility
solvents (see Appendix A).  Little difference was  found between the effects of pump
agitation and air agitation.
     Carry-Out Emissions  -  Carry-out emissions depend on the existence  and use of  a
drainage facility.   Drainage  facilities  are  racks  or shelves used for draining excess
solvent  off  cleaned  parts.  The  drainage facility is standard equipment for some cold
cleaners and is easily and  inexpensively retrofitted for most other  cold cleaners.
Drainage facilities  are  described further  in Section 3.1.2.
     Although  installation  of a  drainage facility is usually no problem,  it will
sometimes  require  a  special  effort to fully use the facility.   As recommended
from ASTM  D-26,  cleaned  parts should drain  at  least 15 seconds.   For  rapid
pace work,  such  as automotive repair, this  time may be perceived  as  too
                                          2-14

-------
delaying; nonetheless, the 15 second drain time should be adhered to.
                  ^         - Waste solvent evaporation is the greatest
source of emissions from cold cleaning.  The amount of waste solvent disposed
of depends  on the size of the cold cleaner and  on  the  frequency  of  disposal.
When the cleaning job  removes large quantities of oil and other contaminants,
or requires  a  high  degree  of cleanliness,  the  solvent will be disposed of
more frequently.  Conversely, if  the  cold cleaner is equipped with an effective
 filter, as many  cold  cleaners present are,  then solid impurities are removed
 and disposal is  required less frequently.
      Waste solvent evaporation  depends not only  upon  the amount but also  upon
 the method of disposal.  Acceptable methods of handling waste  solvent  include
 proper incineration, distillation, and chemical  landfilling, where the waste
 solvent is  buried in enclosed containers and encapsulated by impermeable soil.
 Disposal routes that  result  in total  emission  to the environment include flushing
 into sewers,  spreading waste solvent  for  dust control, such as on dirt roads,
 and landfilling where  the solvent can evaporate or leach into  the soil.  Waste
 solvent evaporation  is  discussed further in Section 3.1.4.
      Sprav  Evaporation -  Evaporation from solvent spraying will increase with
  the pressure  of the  spray,  the fineness  of the spray, and the  tendency to splash
  and  overspray out  of the  tank.   Evaporation is  also  greater when  the  spray  is
  used  constantly and when  volatile solvents are  used.   Preferrably,  the  spraying
  pressure should be less than 10  psig, and the spray  should be a solid,  fluid
  stream.2  The solvent loss from overspraying  and splashing can usually be
  eliminated by sensible design and careful operation.
       Solvent Type - The type of  solvent is a  factor that greatly  affects the
  emission rate from the cold cleaner.  The volatility of the solvent at  the
  ooeratinq temperature is the sinale most important variable.
                                     2-15

-------
     More toxic organics are rarely used in degreasers,  but when they are
they tend to be much better controlled to protect workers and to comply
with OSHA regulations.  These include carbon tetrachloride, benzene and
methyl ethyl ketone.
     The price of the solvent influences the care that is taken to conserve
it.  Thus, more expensive solvents are emitted less.  In addition, the higher
the price of the solvent, the more likely that the wastes will be recovered,
and the more economical control will become.

2.2.2  Open Top Vapor Degreasers
     Vapor degreasers clean through the condensation of hot solvent vapor on
colder metal parts.  Open top vapor degreasers are batch loaded, ue., they
clean only one work load at a time.
     Open top  vapor degreasers are estimated to  result in  the second  largest
emission of the three categories  of degreasers.   It is estimated that open
top vapor degreasers  emit 200 thousand metric tons of organics  per year, this
being about 30 percent  of the national degreasing emissions  (see Appendix  B.3).
2.2.2.1  Design and Operation -
      The Cleaning  Process -  In the  vapor  degreaser, solvent  vapors  condense on
the parts to  be cleaned until  the temperature of the  parts approaches the  boiling
point of  the  solvent.   The  condensing solvent both  dissolves  oils  and provides  a
washing  action to  clean the  parts.   The  selected solvents  boil  at  much lower
temperatures  than  do  the contaminants;  thus,  the solvent/soil  mixture in the
 degreaser boils  to produce  an  essentially pure  solvent  vapor.
      The simplest  cleaning  cycle involves lowering  the  parts into the vapor
 zone  so that the  condensation  action can begin.   When condensation* ceases, the
 parts are slowly withdrawn from  the degreaser.   Residual liquid solvent on the
                                       2-16

-------
parts rapidly evaporates as the parts are removed from the vapor zone.   The
cleaning action is often increased by spraying the parts with solvent (below
the vapor level) or by immersing them into the liquid solvent bath.
     Basic Design - A typical vapor degreaser, shown in Figure 2-3, is a
tank designed to produce and contain solvent vapor.  At least one section of
the tank is equipped with a heating system that uses steam, electricity, or
fuel combustion to boil the solvent.  As the solvent boils, the dense solvent
vapors displace the air within the equipment.  The upper  level of these pure
vapors is controlled by condenser coils  located on the sidewalls of the
degreaser.  These coils, which are supplied with a coolant such as water, are
generally located around the entire  inner surface  of the  degreaser, although
for some smaller equipment they  are  limited to a spiral coil  at one end of  the
degreaser.  Most vapor degreasers are  also equipped with  a water jacket which
provides additional  cooling  and  prevents convection of  solvent  vapors up hot
degreaser walls.
      The  cooling  coils must  be placed  at some distance  below the top edge  of
 the degreaser to  protect the solvent vapor  zone  from  disturbance caused  by air
movement  around the equipment.  This distance from the  top of the  vapor  zone
 to the top  of the degreaser  tank is called  the freeboard and is generally
                      •
 established by the location  of the condenser coils.   The freeboard is  customarily
 50 to 60 percent of the width of the degreaser for solvents with  higher  boiling
 points, such as perch!oroethylene, trichloroethylene, and 1,1,1-trichloroethane.
 For solvents with lower boiling points, such as trichlorotrifluoroethane
 and meth.ylene chloride, degreasers have normally been designed with a
 freeboard equal to at least 75 percent of the degreaser width.  Higher
 freeboards than those recommended will further reduce solvent emissions; however,
 there comes a point where difficulty associated with moving parts into and out

                                      2-17

-------
                                     '. Figure 2-3

                                 OPEN TOP DEGREASER
                          Safety Thermostat
Condensing Coils
                            Freeboard


                              Water Jacket

                           Condensate Trough



                            Water Separator
Temperature
Indicator
Cleanout Door
Solvent Level Sight Glass
    Heating Elements

Work Rest And Protective Grate
                                      2-18

-------
of a degreaser with a high freeboard outweighs  the benefit of increased
emission control.
     Nearly all vapor degreasers are equipped with a water separator such as
that depicted in Figure 2-4.  The condensed solvent and moisture are collected
in a trough below the condenser coils and directed to the water separator.  The
water separator is a simple container which allows the water (being immiscible
and less dense than solvents) to separate from the solvent and decant from the
system while the solvent  flows from the bottom of the chamber back into the
vapor degreaser.
     Variations in Design  -  Figure 2-5, 2-6 and  2-7 show the most popular open
top vapor  degreasers  in use.  These units range in size from table top models
with open  top  dimensions  of 1 foot  by 2 feet up to units which are 110 feet long
and 6 feet wide.   A  typical  open top vapor degreaser is about 3 feet wide by 6
feet long.
     Historically, degreasers of the typical size and smaller have been supplied
with a  single  piece,  unhinged, metal cover.  The  inconvenience of using this
cover has  resulted in general disuse or, at  best, use only  during prolonged
periods  when  the  degreaser would not be operated, for example  on weekends.  More
recently,  small open top  degreasers have been  equipped  with manually operated
 roll-type  plastic covers, canvas curtains,  or  hinged  and  counter-balanced metal
 covers.   Larger units have been equipped with  segmented metal  covers.   Finally,
most  of the  larger open top vapor  degreasers (200 square  feet and  larger) and
 some  of the  smaller degreasers  have had manually  controlled powered covers.
      Lip exhausts such as those shown  in Figure 2-8 are not uncommon although
 in use en less than half of the existing open top vapor degreasers.  These
 exhaust systems are designed to capture solvent vapors escaping from the
 degreasers and carry them  away from the operating personnel.  To the extent
                                      2-19

-------
             Figure 2-4
BASIC PRINCIPLE FOR WATER SEPARATOR
FOR VAPOR DEGREASER



SOLA
01
f^

/ENT
JT


V
i
(WATER)
t
(SOLVENT)

J)
                             WATER
                               OUT

                             WET SOLVENT
                                FROM
                              CONDENSER
                 2-20

-------
                                L      Picture 2-5
                     OPEN TOP DEGREASER WITH OFFSET CONDENSER  COILS
Freeboard
Water
Jacket
Heat
Input
Condenser
Coil
                                                                        Water
                                                                        Separator
                                      2-21

-------
                2-8
DEGREASER WITH LIP EXHAUST
                          Exhaust Inlet
                                           Exhaust
                                           Duct
                     Condensing Unit
               2-24

-------
that they disturb the vapor zone, they increase solvent losses.    For
properly designed exhaust systems, the covers dlose below the
lip exhaust inlet level.
     Applications - Open  top vapor degreasers are usually less capital  intensive
than conveyorized systems, but more capital intensive than cold cleaning
equipment.  They are generally located near the work which is to be cleaned at
convenient sites in the plant, whereas conveyorized vapor degreasers tend to be
located at central cleaning stations requiring transport of parts for cleaning.
Open top degreasers operate manually and are generally used for only a small
portion of the workday or shift.
     Open top vapor degreasers are found primarily in metal working plants,
as described previously.   Furthermore, the larger the plant  the more likely
it will use vapor degreasers instead of cold cleaners.  Vapor degreasers are
generally not used for ordinary maintenance cleaning of metal parts, because
cold cleaners can usually do this cleaning at a lower cost.  An exception may
be maintenance cleaning of electrical parts by means of vapor degreasers because
a high degree of cleanliness is needed and there is intricacy of design.
2.2.2.2  Emissions -
     Unlike cold cleaners, open top vapor degreasers lose a relatively small
proportion of their solvent in the waste material and as liquid carry-out.
Rather, most of the emissions are those vapors that diffuse out of the degreaser.
As with cold cleaning, open top vapor degreasing emissions depend heavily on
the operator.  The major  types of emissions from open top vapor degreasers
are depicted in Figure 2-9.
     An average open top  vapor degreaser emits about 2.5 kilograms per hour
     2                                   2
per m  of opening (0.5 pounds per hour ft ).  This estimate is derived from
                                 2-25

-------
en
                                                              CD
                                                            DIFFUSION AND
                                                            CONVECTION
•v.i '/•;••
 V\,' '••
CARRY-OUT
                                                                                 CONDENSER
                                                                                   COILS
                                 Figure 2-9.   OPEN TOP DECREASED EMISSION POINTS

-------
national consumption data on vapor degreasing solvents  and from seven  EPA
emission tests summarized in Appendix A.   Assuming an average  open  top vapor
                                                     2        2
degreaser would have an open top area of about 1.67 m  (18 ft ), a  typical
emission rate would be 4.2 kilograms per hour or 9,500  kilograms per year
(9 pounds per hour or 10 tons per year).
     Diffusion Losses - Diffusion is the escape of solvent vapors from the
vapor zone out of the degreaser.  Solvent vapors mix with air at the top of
the vapor zone.  This mixing increases with  drafts and with disturbances
from cleaned  parts  being moved  Into and out  of the vapor  zone.  The solvent
vapors  thus diffuse into the room air and into the atmosphere.  These  solvent
losses  include the  convection of warm solvent-laden air upwards out of the
degreaser.
      Diffusion losses  from the  open  top vapor degreaser can be  minimized by
the following actions:
      a.  Closing the cover,
      b.  Minimizing drafts,
      c.  Providing  sufficient  cooling by  the condensing  coils,
      d.  Spraying only below the vapor level,
      e.  Avoiding excessively  massive work loads,
      f.  Maintaining an effective water separator,
      g.  Promptly  repairing leaks.
      The cover must be closed whenever the  degreaser is  not in use.  This
  includes shutdown  hours and times between loads.  Cover design is  also important.
  Improved designs for the  cover  can make it  easier to use thereby facilitating
  more frequent closure.  Covers  should also  be designed to be closed while a
  part is being cleaned  in  the degreaser.
      Drafts  can be minimized by avoiding the  use of ventilation fans  near the

                                       2-27

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 degreaser opening and by placing baffles on the windward side of the degreaser.
 A  baffle is simply a vertical sheet of material placed along the top of the
 degreaser to shield the degreaser from drafts.
     Sufficient cooling by the condensing coils should be attained by following
 design specifications for the degreaser.  Cooling rate is a function of solvent
 type, heat input rate, coolant temperature and coolant flow.  If the vapor
 level does not rise above the midpoint of the cooling coils, then the cooling
                          4
 rate is probably adequate.
     The solvent must not be sprayed above the vapor level  because such
 spraying will cause solvent vapors to mix with the air and  be emitted.   When
 this occurs, the operator should wait for the vapor level to return to normal
 and then should cautiously operate the spray wand only below the vapor level.
     A massive work load will displace a large quantity of  solvent vapor.   The
 work load should not be so massive that the vapor level  drops more than about
 10 on (4 inches)  as the work load is removed from the vapor zone.   Otherwise,
 excessive quantities of solvent vapors will  mix with the air as  the vapor level
 falls and rises.
     The water separator should be kept properly functioning so  that water does
 not return to the surface of the boiling solvent sump.   Water can combine with
 the solvent to form an azeotrope,  a  constant boiling mixture of  solvent and water
 that has a lower vapor density and higher volatility than does pure solvent
      6
 vapor.
     Lastly, it is  important for any leaks  to be repaired properly  and  promptly.
 Special  attention should be paid to  leaks of hot solvent because hot solvent
 evaporates quickly.   These leaks may be greater than they appear or go  completely
unnoticed.
     Carry-Out  Emissions  -  Carry-out emissions  are  the  liquid and vaporous  solvent
entrained on the clean  parts  as  they are  taken  out  of the degreaser.  Crevices
                                  2-28

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and cupped portions of the cleaned parts may contain trapped liquids or vapors
even after the parts appear to be dried.  Also, as the hot cleaned part is with-
drawn from the vapor zone, it drags up solvent vapors and heats solvent-laden
air causing it to convect upwards out of the degreaser.
     There are seven factors which directly effect the rate of carry-out
emissions:
     a.  Porosity or absorbency of work loads,
     b.  Size of work loads in relation to the degreaser1s vapor area,
     c.  Racking parts for drainage,
     d.  Hoist or conveyor speed,
     e.  Cleaning time in the vapor zone,
     f.  Solvent trapped in cleaned parts,
     g.  Drying time.
     Porous or absorbent materials such as cloth, leather, wood or rope will
absorb and trap condensed solvent.  Such materials should never enter a vapor
zone.
     The work load preferably should not occupy more than one-half of the
degreaser's working area.    Otherwise,  vapors  will be pushed out of the
vapor zone by means of a piston  effect.
     Proper racking of parts   is  necessary to  minimize entrainment (cupping)  of
solvent.   For example, parts  should be  positioned vertically with cups  or
crevices facing downward.
     A maximum hoist speed of 3.3 meters  per minute  (11 feet  per minute) has  been
generally accepted as reasonable  by the  degreasing industry.8  Rushing  work
loads into and out of the degreaser will  force solvent vapors out into  the air
and leave liquid solvent on the  cleaned  parts  which  can subsequently  evaporate
into the air.

                                     2-29

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     Cleaning time is  the  period  the  work  load  remains  in the  vapor zone.
If this is not long enough to allow the  work  load  to  reach  the temperature
of the condensing vapor,  the parts will  not dry properly when  removed  from
the vapor zone.   The work load should remain  in  the  vapor zone  until  the  vapors
                                                       is
                                                       10
                                9
no longer condense on the parts.    Usually,  30  seconds  is  sufficient;
however, massive work loads may require longer periods.
     Before the cleaned parts emerge from the  vapor zone,  they  should be
tipped and/or rotated to pour out any collected liquid solvent.   The  work load
should be removed from the vapor zone slowly (at a vertical  speed not to exceed
11 feet per minute).
     Drying time is critical.  It should be long enough to allow the  solvent
to vaporize from the clean part but not significantly longer.   When a hot
dried part rests just above the vapor level, it causes solvent-laden  air to
                                                               12
heat up and rise.  Typically a work load can dry in 15 seconds.
     Waste Solvent Evaporation - Solvent emissions may also result from
disposing of waste solvent sludge in ways where the solvent can evaporate
into the atmosphere.  The volume of waste solvent in sludge from vapor degreasers
is much less than that from cold cleaners for equivalent work loads for two
reasons.  First, the solvent in the vapor degreaser sump can be allowed to become
much more contaminated than the solvent used in a cold cleaner because the
contaminants, with high boiling points, stay in the sump rather than vaporize
into the vapor  zone.  Second, vapor degreasing solvents are halogenated and as
such are generally more expensive; thus, they are more often distilled and
recycled than cold cleaning solvents.
     Although the waste solvent evaporation from vapor degreaser  sludge is
usually less than the diffusion and carry-out  losses, it still contributes
about  5 to  20 percent of  the degreaser's total solvent emissions.    When

                                      2-30

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the solvent in the sump accumulates too much oil  and other contaminants
problems can occur.  The most serious is coating of the heater surfaces, leading
to overheating and subsequent chemical degradation of the solvent.
Thus, the solvent sludge must be cleaned out of the degreaser periodically
and replaced with fresh solvent.
     There are four practices that can reduce and nearly eliminate the
atmospheric evaporation from waste solvent disposal:
     a.  Boil-down,
     b.  Use of in-house distillation,
     c.  Use of contract reclamation services,
     d.  Transfer to acceptable disposal facilities.
     Boil-down is a technique of distilling pure solvent from the contaminated
mixture  in the degeeaser.  As the  contaminated solvent is boiled in the sump.
pure solvent vaporizes and condenses on the cooling coils where it is  routed
to and stored in  a holding tank.   Boil-down can usually reduce the solvent
content  in the contaminated material  to less  than  40 to 45 percent by  volume.
When production schedules permit further boil-down time,considerably lower
                       14
levels can be achieved.
     In-house distillation can  be  an  efficient and often profitable method of
treating waste solvent.  Distilled solvents can normally  be  reused although
additional stabilizers must  be  added  sometimes.  Distillation systems  vary from
centralized  centers  to  relatively  small external stills for  one or more vapor
degreasers.   Through  distillation, the so>vent content  of the waste solvent
sludge can  be  reduced to about  20  percent  by  weight (12-15 percent by  volume)
 in most  operations.     Additional  steam stripping  can  reduce this further.
     Presently most  vapor  degreaser operators do not use  in-house distillation
                                         2-31

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but transfer their waste solvent to another system or company.  Even if the
waste solvent is distilled, there are oils and contaminants, called still
bottoms, that require disposal.  The preferable disposal  methods, for
minimizing solvent evaporation into the atmosphere, are distillation plants
and special incineration plants.  Disposal in landfills after evaporation
is also ased but is less desirable.  Waste solvent disposal  is discussed
in greater detail  in Section 3.1.4.
     Exhaust Emissions - Exhaust systems are often used on  larger than average
open top vapor degreasers.   These systems are called lip  or lateral exhausts
and they draw in solvent-laden air around the top perimeter of the degreaser.
Although a collector of emissions, an exhaust system can  actually increase
evaporation from the bath,  particularly if the exhaust rate is excessive.
Some exhaust systems include carbon adsorbers to collect  the exhaust solvent
for reuse; thus, exhaust emissions can be nearly eliminated if the adsorption
system functions properly.
     In some poorly designed exhaust systems, the ventilation rate can be  too
high.   If the air/vapor interface is disrupted by high ventilation rates,  more
solvent vapors will mix with air and be carried out by the  exhaust system.   A
rule of thumb used by manufacturers of degreaser equipment  and control  systems
is to set the exhaust rate  at 50 cubic feet per minute per  square foot of
                       3               ?  1 fi
degreaser opening  (15 m  per minute •  m ).
     The primary objective  of exhausting is  to assure  that  the threshold limit
value (TLV) as adopted by OSHA is not exceeded.  The exhaust level recommended
above is satisfactory for OSHA requirements on ventilation  except when the quality
of operation of the degreaser is rated as "average" or "poor."  Poor operation is
noted by OSHA to include excess carry-out of the vapor and  liquid solvent,
contamination of the solvent, or improper heat balance.  In these cases, and

                                       2-32

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for solvents with a TLV <_100 opm,  the minimum OSHA ventilation  requirement  is
75 or TOO cubic feet per minute per square foot of degreaser  opening,
Consequently, atmospheric emissions from poorly operated  degreasers  are
increased even further.

2.2.3  Conveyorized Degreesing
     There are several types of conveyorized degreasers,  operating  both  with
cold and vaporized solvents.  An average conveyorized degreaser  emits  about
25 metric tons per year of solvent; however, because of their limited  numbers  they
contribute only about 15 percent of the total solvent degreasing emissions.
Because of their large work capacity conveyorized degreasers  actually  emit
less solvent per part cleaned than either open top vapor degreasers  or cold
cleaners.  Controls discussed in Chapter 3 can reduce this amount still
further.
2.2.3.1  Design and Operation -
     In conveyorized equipment, most, and sometimes all,  of the  manual parts
handling associated with open top vapor degreasing has been eliminated.
Conveyorized degreasers are nearly always hooded or covered.   The enclosure
of a degreaser diminishes solvent losses from the system as the  result of air
movement within the plant.  Conveyorized degreasers are used  by  a broad
spectrum of metalworking industries but are most often found  in  plants where
there is enough production to provide a constant stream of products  to be
degreased.
     There are seven main types of conveyorized degreasers:  monorail, cross-rod,
vibra, fern's wheel, belt, strip, and circuit board cleaners.  While most of the
seven types of conveyorized degreasers may be used with cold or vaporized solvent,
the  first four are almost always  vapor degreasers.
                                       2-33

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     The  cross-rod degreaser  (Figure 2-10)obtains its name from the rods
 between the  two power driven  chains from which parts are supported as they
 are conveyed through the equipment.  The parts are contained in pendant
 baskets or,  where tumbling of the parts is desired, perforated cylinders.
 These cylinders are rotated by a rack and pinion design within the solvent
 and/or the vapor zone.  This  type of equipment lends itself particularly
 well to handling small parts which need to be immersed in solvent to obtain
 satisfactory cleaning or requires tumbling to provide solvent drainage from
 cavities  in  the parts.
     A monorail vapor degreaser (Figure 2-11) is usually chosen when the
 parts to  be  cleaned are being transported between manufacturing operations
 using a monorail conveyor.  This design lends itself to automatic cleaning
 with solvent spray and vapor.  The parts can be moved in one side and out the
 other, as illustrated, or they can turn 180° while in the vapor or spray
 portions  of  the equipment and exit the equipment through a tunnel parallel to
 the entrance.
     In a vibra degreaser (Figure 2-12) dirty parts are fed through a chute
which directs them into a pan flooded with solvent.  The pan is connected
to a spiral  elevator.   The pan and spiral  elevator are  vibrated,
causing the parts  to move from the pan ap the spiral  to the exit chute.   The
parts condense solvent vapor as they are vibrated up the spiral and dry as
soon as they leave the vapor zone.   These degreasers are capable of processing
quantities of small  parts.  Since the vibratory action  creates  considerable
noise, acoustical  insulation of the equipment is needed or the  system must be
enclosed  in a noise-control  booth.
     Three other typical  units are the ferris wheel,  belt,  and  strip degreasers
The ferris wheel  degreaser (Figure 2-13) is  one of the  least expensive and
                                     2-34

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                                     .Figure 2-10
                           CROSS-ROD CONVEYOlRIZED DEGREASER
Conveyor.
Path
Chain
Supports
 Work
 Basket
                                                              Cross  Rods
           Water
           Jacket
Boiling  Chamber
                                           2-35

-------
          i Elflure 2-11
MONORAIL CONVEYORIZED DEGREASER
Spray
Pump
Bo i
Chamber
                              Water
                              Jacket
              2-36

-------
                 I   Figure  2-12

                 VIBRA DEGREASER
                                            Workload  Discharger Chute
Ascending
Vibrating
Trough
Condensers
Distillate
 Trough
Workload
Entry Chute
                                            Distillate Return
                                            For Counter-
                                            flow Wash
                        2-37

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                    Figure 2-13
               FERRIS WHEEL DEGREASER
Work
Basket
                                               Sear to tumble
                                               baskets
          Boiling
          Chamber
                            2-3b

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smallest conveyorized degreasers.   It generally uses  perforated  baskets,
as does the cross-rod degreaser.   The belt degreaser  is  designed to enable
simple and rapid loading and unloading of parts (see  Figure 2-14).   A strip
degreaser resembles a belt degreaser, except that the strip itself is being
cleaned.  The strip degreaser is an integral step in the fabrication and
coating of some sheet metal products.
      Circuit board  cleaners are conveyorized degreasers which use one of the
 previously described  designs specifically  in the production of  printed circuit
 boards.   There  are  three types of  circuit board cleaners:  developers,
 stripoers, and  defluxers.   In  the  production of circuit boards, ultraviolet rays
 are projected through a film  of  an electrical  circuit pattern to create  an
 image on a copper sheet covered  with resist.   The  developer degreaser dissolves
 off the unexposed resist.  This  copper covered board is then dipped in an acid
 bath to etch away the copper that is not covered by the hard, developed
 resist.  Next, the stripper degreaser dissolves off the developed resist.
 Then a wave of solder passes over the bare copper circuit and  bonds to it.
 Lastly,  the defluxer degreaser dissolves  off  the flux left after the solder
  hardens.  Because  of the  nature of  the materials being cleaned, circuit board
  cleaners can use cold  (room temperature)  solvents,  as well as   vapor
  degreasing  processes.
  2.2.3.2  Emissions -
       About  85  percent of the  conveyorized degreasers are vapor types,  leaving
  15 percent as  conveyorized non-boiling degreasers.   Circuit board cleaners
  represent most of the non-boiling conveyorized degreasers.1    An average
  emission rate from a conveyorized vapor degreaser is about 25 metric tons
  per year, while that for non-boiling conveyorized degreasers  is almost 50
  metric  tons per year.  However, most new designs for non-boiling conveyorized
                                        2-39

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                                       Fiqure  t-14
                           MESH BELT CONVEYORIZEO DEGREASER
Conveyor;
Path
                         Boil ing
                         Chamber

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degreasers are far more efficient than the older designs.18  It is  estimated
that the vapor types presently contribute about 75 percent of the conveyorized
degreaser emissions nationally and the non-boiling types contribute the
remaining 25 percent.  On the national scale, about 75,000 metric tons/year
are emitted from conveyorized vapor degreasers, and about 25,000 metric tons/
year are from conveyorized non-boiling degreasers .(see Appendix B.4).  The
major types of emissions from conveyorized degreasers are depicted in Figure 2-15.
     Bath Evaporation  -  For  an equivalent work  load,  the diffusion and convection
of solvent  vapors  from the solvent bath  are  considerably less  for  conveyorized
degreasers  than  for open top degreasers.  This  is  because  the  conveyorized  de-
greasers  are  normally  enclosed except for a  relatively  small entrance  and exit.
      Because  conveyorized  degreasers  are generally automated,  operating  practice
 is a minor factor while design  and  adjustment are major factors affecting
 emissions.   Proper adjustment of the  degreasing system primarily affects bath
 evaporation and  exhaust emissions,  while operation and degreaser design  affect
 carry-out and waste solvent  evaporation.
      The main adjustment affecting  the bath evaporation rate is the heating
 and cooling balance.  Basically, the cooling supplied by the primary
 condensing coils should be sufficient to condense all the vaporized solvent.
 Also, the heating rate needs to be large enough to prevent the vapor level
 from dropping as cold parts enter the vapor zone*
      With regard to equipment design, bath evaporation can be  reduced by
                                                                            19
 minimizing the entrance and exit areas  and by  regulating the  spray system.
 Naturally the smaller the area  of opening,  the lower the  loss  of  solvent
 vapors.  Partial  covers can be  placed over  the openings which silhouette the
 parts  to be  cleaned yet give enough  margin  for safe  passage.   Sprays  should be
  designed or  adjusted  so that they  do not cause turbulence at  the  air/vapor
  interface.   Spray pressure  should  the minimum necessary for proper  performance
                                       2-41

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ro
i
IV)
                DIFFUSION AND

                 CONVECTION
                   ®
WASTE SOLVENT
                                    Figure  2-15.  CONVEYORIZED DEGREASER EMISSION POINTS

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 One well designed system uses the high pressure spray in a contained and
 partially submerged chamber.
       Poor operation can increase convective losses from the solvent bath.
 For instance, if work baskets are overloaded the vapor zone may collapse
 increasing air vapor mixing and, thus, emissions.   This can be avoided by
 following the manufacturer's specification for allowable work load in tons
 per hour, which is determined through an energy balance of the system.   The
 heating capacity of the solvent boiler must be greater than the heat loss due
 to solvent condensation on  the work  load.   Evaporative losses from the  bath
 also increase when there is delay in solvent leak  repair.
       Carry-Out Emissions - Carry out of vapor and liquid  solvent  is  usually
 the major emission  from conveyorized degreasers.   It  is difficult to  reduce
 carry-out emissions, because the  amount of work  load is  inherently large.
       Two factors  affecting carry-out emissions  are the  drainage of cleaned
 parts  and their  drying  time.   Parts  drainage  is  improved by proper racking,
 as  was discussed for open top  vapor  degreasing.  Racking is especially critical
 in  conveyorized degreasers,  because  there  is  little an operator can  do to
 reduce carry-out from a poorly designed system.  The degreaser design should
 allow sufficient space and  time for  the cleaned parts to dry completely.  Some
 designs include a shroud extending from the exit to form a drying tunnel.  Again
 the conveyor speed should not exceed 3.3 meters per minute (11 feet per minute)
              ?n
vertical  rise.
      Exhaust Emissions  - In some cases the emissions  can be high because of
an excessive ventilation rate.   As with open top vapor  degreasers the ventilation
rate should not be much  greater than  15 m3/min-m2 (50 cfm/ft2) of air/solvent
          21
interface.
                                        2-43

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      Waste Solvent Evaporation - Evaporation from waste solvent disposal is
the smallest emission from conveyorized degreasers.  Most conveyorized
degreasers are designed to distill their own solvent.  An external  still  is
attached to the conveyorized degreaser so that used solvent can be  constantly
pumped out, distilled and returned.   Thus, the wastes  will  usually
consist only of still bottoms.  Still, because of the high volume,  waste  solvent
emissions from conveyorized degreasers are significant, typically equalling
                                                                      oo
10 to 20 percent of the total emissions from a conveyorized degreaser.
      As was discussed earlier, the  method of disposal  of the still  bottoms
or undistilled waste solvent will determine the amount of solvent that
evaporates into the atmosphere.
                                       2-44

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  REFERENCES
  1.  T. J. Kearney, "Reply to J. C. Bellinger letter of September 3, 1976,"
      letter of October 1976.
  2.  American Society for Testing and Materials (ASTM), Committee D-26,
      "Recommended Practice for New Source Performance Standards  to Control
      Solvent Metal Cleaning Emissions."
  3.  Surprenant, K. S. and Richards, D. W.  of Dow Chemical  Company,  "Study
      to Support New Source Performance Standards  for Solvent Metal  Cleaning
      Operations," Volume 2, Appendix C.-12,  prepared for Emission  Standards
      and Engineering Division (ESED),  under Contract # 68-02-1329, Task Order
      #9, June 30, 1976.
  4.  Information provided by  K.  S.  Surprenant  by  telephone  to J.  C.  Bellinger
      EPA,  March  3,  1977.
  5.   Dow Chemical  Company,  "Modern  Vapor  Degreasing,"  operating manual, Form #
      100-5185-72.
  6.  ASTM, D-26.,  "Handbook of Vapor Degreasing," ASTM Special Technical
     Publication 310 A, Philadelphia, April, 1976.
  7.  Detrex Chemical Ind., Inc., Detroit, "Todays' Concepts  of Solvent
     Degreasing," operating manual.
 8.  ASTM, D-26, Op. Cit.
 9.  Ibid.
10.   Surprenant,  Op. Cit.
11.   American Society for Testing and Materials Op.  Cit.
12.   Surprenant,  Op. Cit.
13.   "Trip Report - Meeting  of ASTM  Committee D-26 on Halogenated  Organic Solvents,
     Gatlinburg,  Tenn.",  EPA memorandum  from J.  L. Shumaker  to D.  R.  Patrick,
     June 30,  1977.
                                      2-45

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14.   Information  provided  by  Detrex Chemical  Industries, Inc., Letter from
     L.  Schlossberg  to  J.  L.  Shumaker, June 28, 1977.
15.   Surprenant,  Op.  Cit.
16.   ASTM,  D-26,  Op.  Cit.
17.   Bellinger, J.  C.,  "Maximum  Impact of  NSPS on  1985 National Degreasing
     Emissions,"  December,  1975.
18.   Information  provided  by  Bob Porter  of Hollis  Engineering Company, Nashua,
     N.  H.  by telephone to J.  C.  Bellinger, EPA, March 28,  1977.
19.   American Society,  Op.  Cit.
20.   ASTM,  D-26,  Op.  Cit.
21.   Information, K.  S. Surprenant, Op.  Cit.
22.   Ibid.
                                       2-46

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                     3.0   EMISSION  CONTROL TECHNOLOGY

     This  chapter describes individual  emission control  devices applicable
to solvent degreasers, and then shows how these can be combined to form
complete control systems.  Estimates are also provided of the control
efficiency (i.e., percent emission reduction) of individual control devices
along with a range of control efficiency for the complete control systems.
     It is important  to  keep in mind that  optimum  control systems will not
be equivalent for each degreaser design or even each  application  of  a
particular design.   All  of the major devices discribed  in this  chapter will
yield  optimum control in certain  instances;  however,  because  degreaser
 designs and  applications vary,  one or  more of  these devices could be
 completely unsuitable for a given degreaser.   Processes must be evaluated
 individually to determine the optimum control  system.  The individuality
 of systems is such that control efficiencies estimated in this chapter are
 not directly comparable and should not be used to rate one device against
 another.  They are given  only as general  levels of control which one  could
 expect from appropriately  applied technology.

 3.1   EMISSION  CONTROL DEVICES
  3.1.1  Solvent Bath Emissions
       There  are five main devices  that can reduce  emissions from the solvent
  bath:
       1.   Improved cover,
       2.   High  freeboard,
                                       3-1

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     3.  Refrigerated chillers,
     4.  Carbon adsorption,
     5.  Safety switches.
3.1.1.1  Improved Cover -
     The cover is the single most important control  device for open top vapor
degreasers.  Although covers are normally provided on open top degreasers
as standard equipment, they can usually be made more easy to use, and hence
more frequently used, if they are mechanically assisted, powered or automated.
     For vapor degreasers the cover should open and close in a horizontal
motion, so that the air/vapor interface disturbance is minimized.  These
types of covers include roll type plastic covers, canvas curtains and
guillotine covers.  It is usually advantageous on larger open top vapor
degreasers to power the cover.  This may be done pneumatically or electrically,
usually by manual control with an automatic cut off.  The most advanced covering
systems are automated in coordination with the hoist or conveyor.  The cover
can be designed so it will close while the parts are being cleaned and dried.
Thus, the cover would only be opened for a short period of time when the parts
are actually entering or exiting the degreaser.  This is further described in
Section 3.1.3.1.
     On cold cleaners, covers are frequently mechanically assisted by means
of spring loading or counterweighing.  A pedal operated or powered system
can make the cover even more convenient to use.  For specific applications,
two additional types of covers can be used; these are the submerged cover
and the water cover.  The submerged cover  (commercially termed "turbulence
baffle") is a horizontal sheet of material submerged about two inches below
the surface of the liquid solvent that is  vigorously pump agitated.  The
water  cover is simply a  layer of water about two to four inches  thick over a
                                  3-2

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halogenated solvent.   The water cover cannot be used in many applications, however
because the water may corrode the metal surface of the cleaned parts or may
cause chemical degradation of halogenated solvent.
     Covers on cold cleaners which use flammable solvents generally have a
fusible link  in the support arm.  This link is designed to open if the solvent
catches fire, thus  allowing the cover to close and smother  the flames.
Unfortunately, some designs  require  disassembly of  the mechanism  for normal
closing of the cover.   These designs cause  unnecessary emissions  and should  be
avoided.
      Not  all  cold cleaner designs  include  a soaking feature.  Some of  the
 smaller maintenance  units are  designed with an enclosed  sump from which  solvent
 is pumped to a sink  for cleaning parts.   The sink drains back to the sump,
 minimizing the time  during which solvent can evaporate.   Although the  solvent
 is contained, these  units generally include a cover on the sink as a fire
 prevention feature.   It is doubtful that closing this cover can effect a
 significant additional emission reduction.
      Even though conveyorized degreasers are basically covered by design,
 additional cover related control can be achieved by   minimizing the openings*/
 and covering the openings during shutdown  hours.   ASTM has  recommended that
 there not be more than 6 inches (15 cm) clearance  between the parts on the
 conveyor  and the sides of the opening.1  This clearance  can be specifically
 defined  as  the average distance between the edge of  the  openings and  the  part,
 and  termed  the "average  silhouette  clearance."   Average  silhouette  clearance
 can  be appreciably  less  than  6  inches (15  cm) for  parts   that are not unusually
  large.   EPA recommends an  average  silhouette clearance  of 4 inches  (10  cm)  or
  10 percent of the opening's width.
                                   3-3

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     Covers can be easily made for the entrance  and  exit  to  the  conveyorized
degreaser  so that they can be closed immediately after shutting down the
degreaser.   These covers can be made of any material  that impedes drafts
into the degreaser and should cover at least 80  to 90 percent of the
opening.  Closing these covers is most important during the hours immediately
after shutdown, because the hot solvent is cooling and evaporation continues.
Even after the solvent sump has cooled, the down-time cover may be significantly
effective for more volatile vapor degreasing solvents.
     A cover on an open top vapor degreaser has  been shown to reduce total
emissions by approximately 20-40 percent depending upon the frequency of
        2
its use.
     It is impossible to estimate a single control efficiency for the cold
cleaning cover, because the emission  reduction varies  too greatly with respect
to  the  solvent volatility, draft velocity, freeboard  ratio, operating temperature
and agitation.  However,  it can be  estimated that bath evaporation  rate  varies      (
directly with  the  solvent  volatility  at operating temperature.   Although a
closed  cover can  nearly  eliminate  the bath evaporation,  the  cover can do nothing
to  reduce  the  carry-out or waste  solvent  emissions.   Thus,  a  normally closed
cover becomes  effective only  when  bath evaporation  accounts  for an  appreciable
portion of the total  emission.   More  specifically, when  solvent volatility  is
moderate to high  (approximately > 0.3 psi  at 100°F  (2.1  kPa at  38°O),  it is
 significantly effective to close the cover at all  times  when parts  are  not
 being  cleaned manually in the cold cleaner.   It is  especially important that
 the cover be closed when the bath is agitated or heated.  If none of these
 conditions apply, then the cover should at least be closed during long  periods
                                                                                   3
 of cold cleaner disuse, such as during shutdown hours and idle periods  > 1/2  hour.
                                    3-4

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     The effectiveness of a down-time cover on conveyorized degreasers should
be significant, although it is difficult to quantify.  One test found that
about 18 percent of the total emissions was  due to evaporation during down-time.
It is expected that most of this loss could be eliminated by a down-time cover.
3.1.1.2  High Freeboard -
     The freeboard primarily  serves  to reduce drafts near the air/solvent
interface.  An acceptable  freeboard  height  1s usually determined by  the freeboard
ratio,  the  freeboard  height divided  by the  width  (not length) of the degreaser's
air/sol vent area.
      Normally the  freeboard  ratio  is 0.5-0.6  for  the open  top vapor  degreasers,
 except for  very  volatile  solvents, such  as  methylene chloride or fluorocarbon
 solvents, where  a  minimum freeboard ratio of  0.75 is used.   In  fact, the
 American Society for Testing and Materials has  recommended that a  minimum
 freeboard ratio of 0.75 be an alternative control for open top  degreasers using
              5
 all solvents.
      For an open top vapor degreaser that is idling (has no work load), the
 emission reduction from raising a freeboard ratio from 0.5 to 0.75 may typically
 be 25-30 percent.  In fact,  an  increase  in ratio from 0.5 to 1.0 may yield
  about  a 50 percent reduction in emissions.  These are EPA estimates  based on
  a  test by  Dow Chemical,6  The total emission reduction  due  to  the freeboard
  will  generally  be less  for  open top vapor degreasers under  normal work load,
  because the  freeboard is less effective in reducing the carry-out emissions
  than solvent bath emissions.
       The freeboard height seems to have little effect  on  cold  cleaners using
  solvents with low volatilities, such as mineral  spirits,  but provides  significant
  benefits for cold cleaners  using higher volatility solvents,  such  as the
  halogenated ones.  OSHA  requires at least a 6 inch (15 cm)  freeboard for
   cold cleaners.
                                     3-5

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3.1.1.3  Refrigerated Chillers -
     The vapors created within a vapor degreaser are prevented from overflowing
the equipment by means of condenser coils and a freeboard water jacket.
Refrigerated freeboard chillers add to this basic system a second set of
condenser coils located slightly above the primary condenser coils of the
degreaser (see Figure 3*1).   Functionally, the primary condenser coils
control the upper limit of the vapor zone.  The refrigerated freeboard
chilling coils on the other hand impede the diffusion of solvent vapors  from
the vapor zone into the work atmosphere by chilling the air immediately  above
the vapor zone and creating a cold air blanket.  The cold air blanket results
in a sharper temperature gradient.  This reduces the mixing of air and solvent
vapors by narrowing the air/vapor mixing zone.  Finally, the chilling produces a
stable inversion layer which decreases the upward convection of solvent laden air.
     Freeboard chillers operate with refrigerant temperatures in the range of
                                       *
-30 to 5°C.  Although there is a patent on units which operate below 0°C,
most major manufacturers of vapor degreasing equipment offer both above
and below freezing freeboard chillers.
     The recommended operating temperature for below freezing chillers is
-30 to -25°C.  Because of these low temperatures, designs must include a timed
defrost cycle to remove the ice from the coils and restore the heat exchange
efficiency.  Although the liquid water formed during the defrost cycle is
directed to the water separator, some water contamination of the vapor
degreasing solvents is not uncommon.  Water contamination of vapor degreasing
solvents can have an adverse effect on water  soluble stabilizer systems,
although major stabilizer depletions from this are rare.  Water, however,
contributes to equipment corrosion and can diminish the working life  of  the
equipment  significantly.
  US  Patent 3,375,177  issued to AutoSonics  Inc., March 26, 1968.
                                    3-6

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                             I Figure 3-j__
                    REFRIGERATED FREEBOARD CHILLER
                                                 Chiller
Primary
Coils
                                                              Water Jacket
                                3-7

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      Refrigerated freeboard chillers are normally sized by specifying
the cooling capacity per length of perimeter.   The above freezing refrigerated
freeboard chiller is normally designed to achieve a minimum of 500 Btu/hr
(865 W/m-°K) cooling capacity per foot of air/vapor interface perimeter, while
the below freezing refrigerated freeboard chiller is normally designed to
the following specifications:
                                              Minimum Cooling Capacity
      Degreaser Width                         (Btu/hr ft of perimeter)
      < 3.5 ft. (1.1 m)                                  200
      > 3.5 ft. (1.1 m)                                  300
      > 6 ft. (1.8 m)                                    400
      > 8 ft. (2.4 m)                                    500
      > 10 ft. (3.0 m)                                   600
      Normally each pass of finned cooling coil  is expected to remove 100 Btu/hr
                o
ft (173 W/m-°K).    The previous specifications are typical  design standards
used by manufacturers of chillers.  EPA test data indicate  that these design
standards will provide satisfactory emission control, but at present data are
insufficient to confirm that they yield optimum emission control.
      In addition to these, a third type of refrigerated chiller, known as
the refrigerated condenser coil, is available.  Refrigerated condenser coils
do not provide an extra set of chilling coils as the freeboard chillers do,
but replace the primary condenser coils.  If the coolant in the condenser
coils is refrigerated enough, it will create a layer of cold air above the
air/vapor interface.  DuPont and Rucker Ultrasonics have recommended that the
cooling rate of refrigerated condenser coils be equal to 100-120 percent of
the heat input rate in the boiling sump, in order to give optimum emission
        Q
control.   The refrigerated condenser coils are normally used only on small
open top vapor degreasers (especially with fluorocarbon solvent), because
                                      3-8

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energy consumption may be too great when used on larger open top vapor degreasers.
The refrigerated condenser coil offers portability of the open top vapor
degreaser  by excluding the need for plumbing to cool condenser coils with
tap water.
      Tests have been performed for EPA on three below freezing refrigerated
freeboard chillers.  Emission  reductions of 16, 43, and 62 percent were
measured.10  The chiller  which achieved only a 16 percent reduction  in emissions
was installed around 1968 and  the  design was not representative of present
designs.  This  degreaser also  had  a low "uncontrolled" emission rate  of
0.14  Ib/hr  ft2, partly due  to  the  use  of a cover.  The units which achieved
43 and  62 percent  reduction in emissions are  thought  to  be more representative
of present  designs.
       EPA has  not  performed tests  on  above freezing  freeboard  chillers  or
 refrigerated condensing  coils.  However,  tests  are planned which  should
 help  quantify the effectiveness of these  controls.
       Chillers are not normally used on cold cleaners.   While it is  certain
 that a chiller would reduce emissions, especially from units using the more
 volatile solvents, this control is generally too expensive for a normal cold
 cleaner.  A chiller on a cold cleaner should have about the same effectiveness
 as a normally closed cover, but it would cost considerably more.   In fact, a
 chiller  could well cost more  than the cold cleaner itself.  Still, some
 manufacturing cold cleaners with  unusually high emission rates could find
 a chiller appropriate.
 3.1.1.4  Carbon Adsorption -
        Carbon adsorption systems are widely used to  capture solvent emissions
 from metal  cleaning operations.   On  appropriate degreasing processes,  these
 devices  can achieve high  levels of emission  control.  Equipment  design and
 operation  (as  illustrated  in  Figures  3-2, 3-3,  and  3-4)  are  fairly well
                                      3-9

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                                               Figure 3-2.   CARBON ADSORBER
                                                 Solvent-Laden Air Inlet
co
o
                                                                                                       Steam Line
                                                Clean Air Exhaust

-------
    Figure 3-3
ADSORPTION CYCLE
                                            Solvent-Laden

                                              Air Inlet
                                             Activated Carbon
                                                  Bed
                                       Clean Air
                                       Exhaust
          3-11

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                                       Figure 3-4
                                    DESORPTION CYCLE
      Condenser
Recovered 4~
Solvent
                                Solvent laden
                                steam
                                                                                 Activate
                                                                                 Carbon
                                         3-12

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standardized and described in detail  in general  literature, in the Dow
      n                                       12
Report   and in the report by JACA Corporation.
      A well designed and maintained carbon adsorption system will normally
capture in excess of 95 percent of the organic input to the bed.  Carbon
adsorption systems for solvent metal  cleaning normally will  achieve about
                                                      13
40-65 percent reduction of the total  solvent emission.    One reason for
the difference between the theoretical awl actual tsr that tfie ventilation apparatus
of the control system cannot capture all of the solvent vapors and deliver
them to the adsorption bed.  As has been discussed earlier, major loss
areas are drag-out on parts, leaks, spills, and disposal of waste solvent, none
of which are greatly affected by the ventilation system.  Improved ventilation
design can  increase an adsorber's overall emission control efficiency.
Higher ventilation rate alone, however, will not necessarily be advantageous,
since increased turbulence could disrupt the air/vapor  interface  causing an
increase in emissions, all of which would not be captured by the  collection
systems.  The effectiveness  of the ventilation system can also  be improved
through use of drying tunnels and other devices which decrease  losses due
to dragout.
      Poor  operation has  been found to decrease  the control  efficiency  of
carbon  adsorption  systems.   Examples  are dampers that do not open and close
properly, use of  carbon that does not meet  specifications, poor timing  of
the  desorption  cycles, and excessive  inlet  flow  rates.  Desorption  cycles
must be frequent  enough to prevent breakthrough  of  the  carbon beds,  but not
so frequent as  to cause excessive energy waste.  The  degreaser's  air/vapor
interface may  be  disturbed as a  result  of excessive adsorber inlet  flow.  This
can  increase  losses  due to low adsorber  inlet collection  efficiency.  Good
                                  3-13

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operating practice and proper maintenance will  eliminate all  of the above
problems.
      Carbon adsorption systems can effect the  highest achievable level  of
emission control for many degreasing operations.   Its positive aspects are
well known.  There are, however, a few negative aspects that should be
mentioned.  First, where solvent mixtures are used, the collected solvent
emissions will be richer in the more volatile components.  Thus, the
recovered solvent mixture is rarely identical to that used in the cleaning
system.  Second, there are solvent components that are water soluble.  Examples
are acetone or et%.J alcohol used as co-solvents with trichlorotrifluoroethane and
various stabilizers added to many solvents to inhibit decomposition.  These, water
soluble components will be selectively extracted by the steam during the desorption
process.   In  these cases, fresh solvent, stabilizers and/or co-solvents must
be  added  to the recovered solvent before it  is reused.
       Tests performed  on carbon adsorption systems controlling  an  open top
vapor  degreaser and a  conveyorized non-boiling degreaser, measured 60 and
65  percent emission reduction  respectively.    These  levels of  control are
typical  of properly designed,adjusted  and maintained  adsorption systems  on
degreasing operations  which  are suitable for this  type  of control.   Three
other  carbon  adsorption  systems were  tested  and  found to have  low  control
efficiencies.  Two of these  systems  achieved 21  percent and  25  percent emission
                                                                            15
 reductions.   A third  was found to actually  increase  emissions  by 8 percent.
 These  tests exemplify the need for proper application,  design,  operation,
 and maintenance of carbon adsorption systems.
 3.1.1.5  Safety Switches -
       Safety switches are devices used on vapor degreasers  to prevent emissions
 during malfunctions and abnormal  operation.   The five main  types of safety
                                         3-14

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switches are:
      1.  Vapor level control thermostat,
      2.  Condenser water flow switch and thermostat,
      3.  Sump thermostat,
      4.  Solvent level control,
      5.  Spray safety switch.
 The  first four safety switches  listed above  turn  off the  sump  heat while  the
 fifth turns  off  the spray.
      The most important safety switch  is the vapor level control  thermostat.
 This device is activated when solvent  vapor zone rises above the designed
 operating level.   This can occur if the coolant flow is interrupted, for
 example.  When the hot vapors are sensed, the sump heater is turned off thus
 minimizing vapor escape.  This thermostat should be a manual reset type for
 manually operated degreasers.  For conveyorized degreasers, the vapor level
 control  thermostat should activate an alarm system.  These controls should
 be  checked  frequently.
        The condenser water flow switch and thermostat  turn off the sump heat
 when either the condenser water  stops circulating  or  the condenser water becomes
 warmer than specified.   If  the  condenser water flow switch  and  thermostat  is
  properly adjusted, then it  will  serve  as a  back-up for the  safety  vapor
  thermostat  and  also assure  efficient  operation of the condenser coils.
  In summer  months,  the cooling water for condensing coils often  becomes  too
  warm.   In  this case, the thermostats  in a condenser water flow  switch can
  signal a need for improvement, such as increasing the water flow rate.   This
  problem occurred during a test performed for EPA.
        As oils, greases and other contaminants build up  in the solvent, the
  boiling point of  the mixture increases.  Both the  sump  thermostat and solvent
                                       3-15

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level  control  prevent the sump from becoming too hot,  thus  causing solvent
decomposition.   The sump thermostat cuts off the heat  when  the sump temperature
rises  significantly above the solvent's boiling point.   The solvent level
control  turns  off the heat when the liquid level of the boiling sump drops
down to the height of the sump heater coils.  Without  these controls,
excessive heat could decompose the solvent, emitting such things as hydrochloric
acid.
      The spray safety switch is not used as often as  the other safety switches,
but it can offer a significant benefit.  Specifically, if the vapor level
drops  below a  specified level, then the pump for the spray application will
be cut off until the normal vapor level is resumed.  Thus,  the spray safety
switch prevents spraying above the vapor level which causes excessive
emissions.
      The effectiveness of the five safety switches cannot be quantified
because their operation results from poor degreaser maintenance and use.
Nevertheless,  considering the fact that vapor degreasers do not always
receive proper attention and maintenance, it is expected that the safety
switches will  provide a significant reduction in emissions for typical vapor
degreasing operations.
3.1.2  Controls to Minimize Carry-out
      Carry-out emissions are the solvent emissions that result when clean
parts still containing  liquids or vapors are extracted from the vapor degreaser.
As described in chapter 2, good operating practices are the primary method of
reducing  carry-out emissions.  Furthermore, there  are devices that can help
minimize  the carry-out  from cold cleaners and conveyorized degreasers, but
not generally  from open top vapor degreasers.
                                     3-16

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      The main control  device for carry-out emissions  from cold cleaners  is
a simple drainage facility.   The two types of drainage facilities are the
external and internal drainage racks (or shelves).   The external drainage rack
is attached to the side of the cold cleaaer at the top.  The liquid solvent
from the cleaned parts drains into a tra«jj| ami is returned to the cold cleaning
bath.  This control is Inexpensive Sal easily wtrotttted.  An internal
drainage facility is located beneath the cover.  It may be a basket that
is suspended over the solvent bath, or a shelf from which the solvent drains.
Particularly with solvents of higher volatilities  (i.e., much greater than
that of  mineral  spirits), an  internal drainage facility can prevent a
significant solvent  emission.   The  internal  drainage  facility sometimes  cannot
be reasonably  retrofitted, because  there may  not be enough room inside the
 cold cleaner  to  drain  parts  while  cleaning other parts.
       The  main control devices  for carry-out emissions from conveyorized
 degreasers are a drying  tunnel  and rotating  baskets.   A drying  tunnel  is
 simply an  extension  from the exit  of the  conveyorized degreaser.   This  tunnel
 extension  gives  cleaned  parts more time to dry completely.  The drying  tunnel
 should work particularly well in combination with  carbon  adsorption.   Drying
 tunnels can be retrofitted,  if there is adequate  space.  Rotating baskets ^
 may be used on cross-rod degreasers and ferris wheel  degreasers.  A rotating
 basket is a perforated cylinder containing parts  to be cleaned that is slowly
 rotated through the cleaning system, so that the parts cannot trap liquid
 solvent.  Rotating baskets are designed into the conveyorized system and hence
 are not easily  retrofitted.
       Conveyors themselves can contribute to carry-out emissions.  Some
 designs cause less emissions than others.   In general, these emissions are
 directly  proportional to the surface area entering and leaving  the cleaning
                                       3-17

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zone.   One design, uses small  pushers to move parts  along fixed rods which
support the work.   This design is advertised to carry-out 70 percent less
solvent than conventional  wire mesh conveyors.
     The effectiveness of control devices that help  minimize carry-out
emissions cannot be quantified.  The amount of carry-out depends too much
on the type of work loads (shape and crevices) and the quality of operation.
Nevertheless, it is obvious that if the exiting cleaning parts visibly show
liquid solvent, then carry-out emissions will be substantial.
3.1.3  Controls for Solvent Bath and Carry-out Emjssjpns Combi ned
     Two control systems reduce both solvent bath and carry-out emissions.
They are the automated cover-conveyor system and a refrigeration condensation
system.  Both systems are relatively new designs and infrequently used in
practice.  They are somewhat complex and expensive in relation to most other
control devices.
3.1.3.1  Automated Cover-Conveyor System -
     The purpose of an automated cover-conveyor system is to close the
cover of an open top vapor degreaser when parts are being cleaned and
dried.  Thus, the cover is open only for the short period of time when dry
parts are actually entering or exiting.  (It is possible to use this system
on a cold cleaner but  the solvent volatility and losses would generally
have to be very high to justify the expense of such a system.)  The automated
cover must be capable  of closing while the part is inside the degreaser.   If
the part is  conveyed by means  of a  cable and hoist, then the cover  can
close horizontally and be split  into two parts so that  it closes at the  center
where the cable is located.   If  the  parts  are conveyed  by means of  a shelf
that automatically lowers and  rises, then  the vapor degreaser can be
covered  by  a permanent enclosure with  a  vertical door,  (See  Figure  3-5).
                                    3-18

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                                                                   &.-
-------
Automated conveyor systems include adjustable timing delays for cleaning
and drying and automatic cut-offs to position the work load for cooking and
drying.
     Because emissions could occur only for the short period of time when
dry parts are entering or exiting the automated degreaser, it is expected
that an  automated cover-conveyor system would provide highly effective
control.
3.1.3.2   Refrigeration Condensation -
     Direct condensation of solvent vapors from exhaust air streams is a
possible although perhaps difficult means of recovering solvent.  Some
                                                           20
insight  into the problem is gained by examining Figure 3-6.
     Condensation will occur when an air/vapor stream is refrigerated to
a temperature where the solvent's equilibrium vapor pressure is less than
its actual vapor pressure.  The actual vapor pressure is calculated by
multiplying the percent solvent vapor concentration (by volume) by the total
pressure (usually atmospheric).  For example, 1000 ppm of perchloroethylene
at atmospheric pressure yields an actual vapor pressure of 0.76 mm Hg
(0.1 percent concentration multiplied by 760 mm Hg).  Extrapolating from
the graph, 0.76 mm Hg intersects curve #9 at -25°C; thus, condensation
occurs below -25°C for perchloroethylene at 1000 ppm and 1 atmosphere.
     Although solvent concentrations may reach 1000 ppm momentarily, the
average  concentration of chlorinated solvent vapors from typical operations
                                       21
is about 300 ppm (0.23 millimeters Hg).    Consequently, direct condensation
of perchloroethylene would not usually occur until the temperature of the
air/vapor stream was reduced to at least -40°C.
     There are two major problems with refrigeration condensation.  First,
at these low temperatures, ice forms rapidly on the heat exchange surfaces,
reducing the heat exchange efficiency.  The ice formation also requires the removal
                                        3-20

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                Figure  3-6.   Vapor Pressures ot Several  Solvents
1

1
4
5
Methytane chloride


1 1 l-TrichloroMhane
Carbon tttrachloride
fi
7
8
9
10
Ethytene dichloride (1,2-dichloroethana)
Trichloroethytene
1 , 1 ,2-Trichloroethane
Perchloroethylene
Stoddard Solvent
Til
\?
ii
I4
15





                                JO-   40-   50"  60-  70- 60- 90' IOO'   |20-   I4Q-  I6Q-  ISO' 200' "°' "°'C
10.000
 5000
  1000
      -20    -10    *0    10   20   30  40  50 o 60 70  80 90100   12O  140  160 180 20O 220 24O
                                               3-21

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of a large amount of heat (1300 Btu's per pound)  which will  add significantly
to the cost of this control,  Second, when condensation occurs a fine mist of
liquid solvent is formed.  The problem is in removing this mist from the air
stream.
     This analysis indicates that it would be difficult to control  emissions
from degreasers with refrigeration condensation,   However, this rests on two
assumptions:  (1) 1 atmosphere pressure is maintained and (2)  vapors cannot
be collected in higher concentrations,  Still, this  does not preclude its
successful use,  An example is one design which was  reported after  the initial
EPA test program had been completed,  The equipment  manufacturer, Autosonics
Inc., reported successful emission control using  a prototype of their design,
called the "Zero-Emission" vapor degreaser.  This system employs refrigeration
condensation along with carbon adsorption and is  reported to be able to
capture solvent vapors with unusually high efficiency.  EPA tests on this
degreaser are planned,
3.1,4  Control of Waste Solvent Evaporation
3,1,4,1  Current Practices -
     Emissions from waste solvent occur through a number of diverse routes,
none of which can be easily monitored or quantified.  Based on the  limited
information currently available (see Appendix B,5),  it is estimated that
about 280 thousand metric tons of waste solvent were disposed of from metal
degreasing operations in 1974,  This is approximately one-third of  the total
metal degreasing emissions.
     Most of this waste is disposed of in a manner such that it can evaporate
into the atmosphere,  A large fraction is indiscriminately dumped into
drains or onto the grounds surrounding the using  facility.  Some waste
solvent is stored in open containers and evaporates.  A small amount of waste
solvent finds its way to municipal or chemical landfills that make  no
                                     3-22

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attempt to encapsulate the solvent.  Some larger companies have used
deep well  injection, but overall  this is considered an insignificant disposal
route for waste solvent from degreasing.  It has been estimated that these
four disposal routes account for ^35 percent of the total  waste solvent
load.
     It is convenient for automotive maintenance facilities to dispose of
their waste solvent along with their waste crankcase oil.   Perhaps as much
as 15 percent of the total waste solvent load (or <33 percent of the
waste solvent from maintenance cold cleaners) enters this route.  Crankcase
oil  is reprocessed, rerefined, used for dust control on unpaved roads or handled
in other ways, none of which pay significant attention to the solvent
fraction.
     Properly controlled incineration is one of the few disposal routes
which does not result in organic emissions to the atmosphere.  However,
only a small fraction (^5 percent) of waste solvent is believed to be disposed
of in this manner.
     Solvent reclamation is the most environmentally acceptable route for
waste solvent.  It  is believed that ^45 percent of the waste solvent load
                                        22 23
is being reclaimed  through distillation.  '    Primarily, halogenated
solvents are distilled; petroleum related solvents, such as mineral spirits,
are  more difficult  and less profitable  to distill, because such solvents
are  flammable and inexpensive, compared to halogenated solvents.
3.1.4.2  Recommended Practices -
     Reclamation Services - Reclamation services collect waste solvent, distill
it,  and return the  reclaimed portion to the  solvent  user.  Charges vary but
are  roughly  equal to one  half  the market  value  of  the  solvent.  In industrial
 areas where  large numbers of users  are  present,  solvent scavenging and
 reclamation  is being practiced profitably.   In  rural  areas, where users are
                                      3-23

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separated by large distances, collection and transportation is  a limiting
factor.   However, suitable collection systems could be devised  and reclamation
service could be expanded beyond the industrial  areas.  For example, it would
be possible for the rural user to store waste solvent in sealed containers
until sufficient volume is acquired to make collection economical.
     Another alternative is offered by the Safety Kleen Corporation.  This
firm provides a service of supplying both the solvent and cold  cleaning
equipment to users.  The solvent used is periodically collected and replaced
with fresh solvent by the company and the used solvent is distilled at central
locations.  The firm operates in industrial areas throughout the U.S.
     In-House Reelamation - Many large users practice in-house  reclamation.
In vapor degreasing, the use of stills is fairly common.  For instance,
nearly all conveyorized vapor degreasers and large open top degreasers are
equipped with stills, (see Figure 3-7).  These stills have been customarily
used because they reduce the maintenance cost of cleaning the vapor degreasing
system, enable the system to remove soils collected without interrupting
the  cleaning process and recover valuable quantities of solvent.  The Dow
Report estimated that the total yearly cost of in-house reclamation of
chlorinated solvents can be  recovered from the first  350 gallons distilled.
Nonchlorinated solvents, because of their flammability and lower recovery
value, would require 6 to 12 times this quantity.
     Bottoms from all distillation columns are of a hazardous nature,
containing metals, sludge, residual solvent, etc.  They must be disposed
of properly in chemical  landfills or preferably  through a properly  controlled
high temperature  incineration facility.
     Each solvent  class  exhibits its own peculiar problems in distillation.
Chlorinated solvents are partially stripped  of their  stabilizers  during
                                 3-24

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                                Figure 3-7
                            EXTERNAL STILL
Water
Separator
Condensate
Collection
Trough

Steam Inlets
                                                                        Freeboard
                                                                        Water Jacket
                                                                      Water Inlet
                                                                        Automatic
                                                                        Level Control
                                                                     >Steam Outlets
                                          3-25

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 distillation.  These must be replaced to avoid chemical decomposition  of
 the  recovered solvent.  Nonchlorinated solvents are quite flammable and
 require equipment designed to prevent fires and explosions.  Solvent blends
 usually consist of solvents of different boiling points; thus, the solvent
 initially recovered has a higher portion of lower boiling point solvents.
 Certain contaminates can also greatly increase the difficulty of distilling
 any  solvent.  For example, azeotropes can form between contaminates and solvents
 during distillation, making separation difficult.  Also, adverse chemical
 reactions can occur.  For these reasons distillation service companies
 generally analyze waste solvent.  The company using in-house distillation
 can often eliminate analysis and avoid many of the problems encountered by
 services which distill a mixture of solvents from different users, because the
 solvents and the contaminants are known.
     Direct Incineration - Direct incineration in a properly controlled
 facility is another environmentally acceptable disposal route for waste
 solvent.  Incineration does not, however, produce a useable product and
 often requires significant amounts of supplementary fuel.   For these
 reasons, it is not as attractive as reclamation.   Nonchlorinated solvents are
 fuel  oil grade waste and after simple filtration  of hazardous contaminates
 could provide the heat value necessary for incineration of chlorinated
 compounds.   However, their fuel  value will  be considerably less  than their
 solvent value.
     There  are approximately 25  to 50 facilities  in the United States  capable
 of acceptably incinerating chlorinated solvents.   Such facilities  require high
temperatures H200°C),  sufficient residence time (about 2 seconds),  and
sophisticated exhaust gas  cleaning equipment to remove halogenated compounds
 (primarily  HC1),  particulates,  and other  contaminants.   Capital  investment to
                                     3-26

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build this type of incinerator is significant (1.5 to 5 million dollars for
6 gallon of waste per minute capacity).  Operating costs have been estimated
                                          24
at less than 2
-------
 3.1.5.1  Incineration -
     Incineration has been used for many years to control emissions of organics
 to the atmosphere.  For degreasing operations, it could be applied most
 easily to systems using petroleum hydrocarbons and oxygenated solvents which
 readily combust to carbon dioxide and water.  Application to systems using
 halogenated hydrocarbons would be more difficult.  Although halogenated
 hydrocarbons are non-flammable under normal conditions, they can be pyrolyzed
 at temperatures in the incineration range.  The pyrolytic decomposition of
 chlorinated hydrocarbons, for example, will release chlorine, hydrochloric
 acid, and phosgene depending upon the conditions of oxidation.  These products
would have to be removed from the off-gas stream of the incinerator using
 sophisticated gas cleaning equipment before exhausting to the atmosphere.
     The cost of incineration could also be high.  First, capital requirements
are generally large, particularly in comparison to the relatively low cost of
most degreasers.  Furthermore, costs would be significantly increased with
 the addition of gas  cleaning equipment, were that needed.  Next, solvent
 concentrations in exhaust streams are frequently below the range required
to sustain combustion; thus, supplemental fuel would be required.  Scarce fuel
resources would make this a limiting factor.
3.1.5.2  Liquid Absorption -
     Liquid absorption is a well  known process that has been investigated for
use in  solvent metal  cleaning.  For example, trichloroethylene vapors in air
could be substantially reduced by absorption in mineral oil.   However,  at an
absorption column temperature of 30°C (86°F), the air stream leaving the
column  might contain about 120 ppm mineral  oil.  Thus, the process  could
result  in control of one hydrocarbon but emission of another at a nearly
                               I O
equal or possibly greater rate.
                                  3-28

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     Chilling the absorbing fluid would reduce its concentration in the
exhaust air.  However, cooling to a temperature below 0°C (32°F) would cause
ice formation in the column since water is insoluble in mineral oil.  Although
this could be avoided by prerefHgeration of the air stream, the use of
refrigeration would greatly increase energy consumption.  Finally, the energy
requirement for recovering the solvent from the mineral oil is great.  Thus,
it appears  that this method of emission control is impractical except for the
recovery of  (1) high concentrations of solvent vapors  in air,  (2) very valuable
                                           19
vapors or  (3) highly toxic chemical vapors.

3.2  COMPLETE CONTROL SYSTEMS
     A complete emission  control  system utilizes  both  control  equipment  and
operating  procedures.   Although  controls  can  be combined in many ways  to form
many different  control  systems,  two basic control  systems  for  each  type
degreaser  are presented here.   Generally, control  system A consists of proper
operating  practices and simple,  inexpensive  control  equipment.  Control
system B consists of system A plus other  devices  that increase the effectiveness
of control.  The details of control  system A or B can be modified to arrive
 at the level of control needed.
      The emission control efficiency of reasonably well designed and maintained
 control  systems is estimated from the present test data base.   Control systems
 which are seriously defective are not uncommon.  A few such systems were
 even recommended unintentionally by control system vendors to EPA as being
 exemplary; it required close inspection  and sometimes emission measurements
 to discover that the systems were defective.
                                      3-29

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3.2.1  Cold Cleaning Control Systems
     The most important emission control  for cold cleaners is the control
of waste solvent.  The waste solvent needs to be reclaimed or disposed of so
that a minimum evaporates into the atmosphere.  Next in importance are the
operating practices of closing the cover and draining cleaned parts.   Several
other control techniques become significant only in a small fraction of
applications.  The control devices and operating practices for control
systems A and B are summarized in Table 3-1.
     There is not a large difference in effect between system A and B,
because most of the cold cleaning emissions are controlled in system A.  If
the requirements of system A were followed conscientiously by nearly all
of the cold cleaning operators, there would be little need for the additional
system B requirements.  However, because cold cleaning operators can tend
to be lax in keeping the cover closed, equipment requirements #1 and #4  in            ^
system B are added.  Similarly, the modifications for #2 and the equipment
requirements in #3 would effect significant emission reductions in a few
applications.
     Although the effectiveness of the control systems depends greatly on
the quality of operation, average cases have  been approximated, (see Appendix B.2).
System A could reduce  cold  cleaning emissions by 50  (±20) percent
and  system B may reduce  it  by 53  (+20) percent.  The lower end of the  range
represents the emission  reduction projected for poor compliance, and  the higher
end  represents excellent  compliance.  As  can  be readily seen from these  estimates,
the  expected benefit  from system  B  is only  slightly better than that  for
system A for an  average  cold  cleaner,  assuming low volatility
solvents.  This  difference  is  small because the additional devices required
in system  B  generally control  only  bath evaporation, which represents about          M

                                         3-30

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              TABLE 3-1.   CONTROL SYSTEMS FOR COLD CLEANING


Control System A

Control Equipment:

     1.  Cover

     2.  Facility for draining cleaned parts

     3.  Permanent, conspicuous label, summarizing the operating requirements

Operating Requirements:

     1.  Do not dispose of waste solvent or transfer it to another party,
sucK that greater than 20 percent of the waste (by weight) can evaporate
into the atmosphere.*  Store waste solvent onlv in covered containers.

     2.  Close degreaser cover whenever not handling parts in the cleaner.

     3.  Drain cleaned parts for at least 15 seconds or until dripping ceases.

Control System B

Control Equipment:

     1.  Cover:   Same as in System A, except if (a) solvent volatility is
greater than 2 kPa  (15 mm Hg or 0.3 psi) measured at 38°C  (100°F),**
(b) solvent is agitated, or (c) solvent is heated, then the cover must
be designed so that it can be easily operated with one hand.  (Covers for
larger deqreasers may require mechanical assistance, by spring loading,
counterweiqhtinq or Dowered systems.)

     2.  Drainage facility:  Same as in System A, except that if solvent
volatility is greater than about 4.3 kPa (32 mm Hg or 0.6  psi) measured at
38°C  (100°F), then  the drainage facility must be  internal, so that parts are
enclosed under the cover while draining.  The drainage facility may be
external for applications where an internal type  cannot fit into the cleaning
system.

     3.  Label:   Same as in System A

     4.  If used, the solvent spray must be a solid, fluid stream (not a
fine,  atomized or shower type spray) and at a pressure which does not cause
excessive splashing.

     5.  Major control device for highly volatile solvents:  If the solvent
volatility is > 4.3 kPa  (33 mm Hg or 0.6 psi) measured at  38°C (100°F), or
if solvent is heated above 50°C  (120°F), then one of the following control
devices must be used:

     a.  Freeboard  that gives a freeboard ratio*** >_0.7

     b.  Water cover (solvent must be insoluble in and heavier than water)

     c.  Other systems of equivalent control, such as a refrigerated chiller
or carbon adsorption.

Operating Requirement.*;:

      Same as  in System A


*Water and solid  waste regulations must also be complied with..
**Generally solvents consisting  primarily of mineral spirits (Stoddard) have
volatilities  < 2  kPa.
***Freeboard  ratio  is  defined as  the  freeboard height divided by the
width of the  degreaser.


                                       3-31

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 20  to  30 percent of  the  total emission from an average cold cleaner.   For
 cold cleaners with high  volatility solvents, bath evaporation may
 contribute ^50 percent of the total emission; ft is estimated that system B
 may achieve 69 (+20) percent control efficiency, whereas system A might
 experience only 55 (+20) percent control.
 3.2.2  Control Systems for Open Top Vapor Degreasing
     The basic elements  of a control system for open top vapor degreasers
 are proper operating practices and use of control equipment.  There are
 about ten main operating practices.  The control equipment includes a  cover,
 safety switches and a major control device, either high freeboard, refrigerated
 chiller, enclosed design or carbon adsorption.   Two control systems for open
 top vapor degreasers are outlined in Table 3-2.
     The vapor level thermostat is not included because it is already  required
 by OSHA on "open surface vapor degreasing tanks."  The sump thermostat and
 solvent level control are used primarily to prevent solvent degradation and
 protect the equipment and thus are also not included here.   The emission
 reduction by these controls is a secondary effect in any event.   The two
 safety switches presented serve primarily to reduce vapor  solvent emissions.
     System A may reduce open top vapor degreasing emissions by 45 (+15) percent,
 and system B may reduce them by 60 (+J5)  percent.  For an average size
 open top vapor degreaser, system A and B  would  reduce emissions  from 9.5 m
 tons/year down to about  5.0 and 3.8 m tons/year, respectively.  It is  clear that
 system B is appreciably more effective than system A.
 3.2.3  Control Systems  for Conveyorized Degreasers
     Control  devices  tend to work most effectively  on conveyorized degreasers»
mainly because they are enclosed.   Since  these  control  devices can usually
 result in solvent savings,  they often will  net  an annualized profit.
                                  3-32

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    TABLE 3-2.  COMPLETE CONTROL SYSTEMS FOR OPEN TOP VAPOR DE6REASERS

Control  System  A
Control  Equipment:
     1.   Cover  that can  be opened and closed easily without disturbing  the
vapor zone.
Operating Requirements:
     1.  Keep cover closed at all times  except when processing work loads
through the degreaser.
     2.  Minimize solvent carry-out by  the  following measures:
     t:  K S8 X STJ"!} ffi'SR— «          0c         ,
     c   Degrease the work load in the vapor zone at  least 30 sec. or until
 visually ^ry.^  ^^^ porQus Qr absorbent materials,  such  as  cloth, leather,
 wood or rope.
      4.  Work  loads  should not occupy more than half of  the degreaser 's open
 top area.
      5.  The vapor level should not drop more than 10 cm (4 in)  when  the
 work load enters the vapor zone.
      6.  Never spray above the vapor level.
      7.  Repair solvent leaks immediately, or shutdown the degreaser.
      8.  Do not dispose of waste  solvent or  transfer It to another party
                                                              1
                       ,
  fans  should not be used near the degreaser opening.
      10.   Water should not be visually detectable in  solvent  exiting the water
  separator.
  Control  System JL
  Control  Equipment:
       1.   Cover  (same as in  system A).
       2.   Safety switches
       a   Condenser flow switch  ana tnermostat - Csnuts off sump neat if condenser
  C°°lan                      ^ (IhuTs'oVspTay pump if the vapor level  drops
       b
  excessively, about 10 cm (4 in).
       3.  Major Control Device:
       Either-  a   Freeboard ratio greater than  or equal  to 0.75, and if the
   degreaser opening is > 1 m2 (10 ft*), the cover must  be  powered,
                b   Refrigerated chiller,
                c'  Enclosed design (cover or door opens only when the dry part
   is  actually entering orbiting the denser.),                 .3         .2
   (50 cfm/ft2)  of  air/vapor area (when cover is open),  and exhausting <25 ppm
   solvent averaged  over one c^^^tSd^S^control  efficiency,
   equivalent to or better than any of the  above.
        4.  Permanent,  conspicuous  label, summarizing operating procedures  #1  to #6.

   Operating Requirements:
        Same as  in  System  A

                                        3-33

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Two recommended control systems for conveyorized degreasers are shown in
Table 3-3.  Control system A requires only proper operating procedures which
can be implemented, in most cases, without large capital expenditures.  Control
system B, on the other hand, requires a major control device.
     Major control devices can provide effective and economical control for
conveyorized degreasers.  A refrigerated chiller will tend to have a high
control efficiency, because room drafts generally do not disturb the cold air
blanket.  A carbon adsorber also tends to yield a high control efficiency,
because collection systems are more effective and inlet streams contain
higher solvent concentrations for conveyorized degreasers than for open top
vapor degreasers.
     Small scale conveyorized degreasing applications can result in significantly
high annualized costs from using a major control  device.  Consequently, many
operators raay be motivated to use the less expensive open top vapor degreaser
in place of a conveyorized one, even though more solvent is emitted for an            *
equivalent work. load.   Thus, it is reasonable to exempt eonveyorized  degreasers with
less than 2.0 m  of air/vapor interface from requirement of a major control device.
     The remaining three control  devices recommended in system B should entail
nominal  expense in relation to their potential  solvent savings.   Because of
the wide diversity of applications for conveyorized  degreasing,  there may be
a few applications where the drying tunnel  or a minimized opening  may be
impractical;  thus, occasional  exceptions may have to be made for these two
requirements.   For example, a plant might not have enough space  available  to
permit use of a drying tunnel; also, hanging parts may occasionally swing
from a conveyor line more than the clearance allowed by the control requirement.
     The control efficiency for system A is estimated  at 25 C±5) percent and
for system B,  60 (±10) percent.   Emissions  from a typical  conveyorized  degreaser

                                       ' 3-34

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         TABLE 3-3.   CONTROL  SYSTEMS  FOR  CONVEYORIZED DEGREASERS


Control  System A

Control  Equipment:  None

Operating Requirements:
     i   Exhaust ventilation should not exceed 20 m3/min per m2 (65 cfm per ft  )
of degreaSrTpening! unless necessary to meet OSHA requirements.   Work place
fans should not be used near the degreaser opemng.

     2.  Minimize carry-out emissions by:
                              conTeyorlpeed at < 3.3 m/min (11 ft/min).

      3    Do  not  dispose of waste solvent or transfer it to another party such
 that  greater than  20  percent of the waste  (by weight) can evaporate
 into  the atmosphere.   Store waste solvent  only in covered containers.

      4.   Repair  solvent leaks  immediately, or shutdown the degreaser.

      5.   Water should not be visibly  detectable  in  the solvent exiting  the
 water separator.

 Control  System B

 Control  Equipment:
      1.   Major control devices;  the degreaser must  be  controlled  by  either:
      b          asorptSon1 Astern, with ventilation >15 m^/min per m2  (50 cfm/ft2)
 of air/vapor area (when down-time covers are open), and exhausting <25  ppm of
 solvent by volume averaged over a complete adsorption cycle, or
      c.  System demonstrated to have control efficiency -qumlent to or  better
 than either of the above.

      2   Either a drying tunnel, or another means such as rotating (tumbling)
 basket] sufficient to prevent cleaned parts from carrying out solvent  nquid
 or vapor.

      3.  Safety switches

      a.  Condenser flow  switch and thermostat -  (shuts off sump heat if
 coolant is either not circulating or too warm).
      b.  Spray  safety switch -  (shuts off spray  pump or conveyor  if the vapor
      !  drons excessively, e.g. >  10 cm (4 in.)).
      c  Sapor  ?evel control thermostat - (shuts off sump heat when vapor
  level  rises too high).
      4  Minimized openings:  Entrances and exits should silhouette work
  loads  so that the average  clearance  (between parts and the edge of the
  degreaser opening) is either <10 cm  (4  in.) or <10 percent of  the width
  of the opening.
      5.  Down-time covers: Covers  should be provided  for closing off  the
  entrance and  exit during shutdown hours.

  Operating  Requirements:

       1. to 5.  Same  as  for System A

       6   Down-time cover must be placed over  entrances and  exits  of conveyorized
  degreasers immediately after the conveyor and  exhaust are  shutdown
  and removed just before they are started up.

                                          3-35

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may decrease from 27 to 'vZO and Ml  (metric 1 tons/yr for systems A and B,
respectively.  Thus, system B offers a much greater emission reduction per
degreaser for conveyorfzed degreasers than for cold cleaners or open top vapor
degreasers.
                                          3-36

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3.3  REFERENCES
1.  American Society for Testing and Materials (ASTM), Committee D-26,
    "Recommended Practice for New Source Performance Standards to Control
    Solvent Metal Cleaning Emissions."
2.  Surprenant, K. S. and Richards, D. W. of Dow Chemical Company, "Study
    to Support New Source Performance Standards for Solvent Metal Cleaning
    Operations,"  Vol. 2, prepared for Emission Standards and Engineering
    Division  (ESED), under Contract # 68-02-1329, Task Order #9, June 30, 1976.
3.  Ibid.
4.  Ibid,  Appendix C-9.
5.  American  Society for Testing Materials,  Op. Cit.
6.  Surprenant,  K. S.,  Op. Cit, Appendix C-12.
7.   Information  provided by  H.  A.  Rowan  of Magnus Division  of  Economics  Lab.
     Inc.,  S.  Plainfield, N.  J.,  by telephone to J.  C. Bellinger,  EPA
    March  28, 1977.
 8.   Information  provided by  J.  Picorney of  Baron  Blakeslee  Inc.,  Chicago,
     by telephone to  J.  C.  Bellinger,  EPA, November  18, 1976.
 9.  "Trip Report - Collins tnow Rucker Ultrasonics) Inc., Concord, Calif."
     EPA memorandum from J. C. Bollinger to  D. R.  Patrick, November 5, 1976.
10.  Surprenant, K. S., Op. Cit., Appendices C-3,  C-5, and C-7.
11.  Ibid, pg. 4-5.
12.  JACA  Corp., Fort Washington, Pa., "Air Pollution Control  of Hydrocarbon
     Emissions - Solvent Metal Cleaning  Operations,"  prepared for EPA, Office
     of Technology Transfer, Seminar:  "Upgrading Metal Machining, Fabricating,
     and Coating Operations to Reduce Pollution."
13.  Surprenant, *C. S.,  Op. Cit., pg. 4-59.
14.  Ibid, Appendices C-10 and C-ll.
                                          3-37

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15.  Ibid, Appendices C-4, C-5, and C-8.
16.  Ibid, Appendix C-7.
17.  Kearney, T. J., Detrex Chem. Inc., letter to J.  F.  Durham, EPA,
     February 17, 1976.
18.  Surprenant, 1C. S., Op. Cit.
19.  Ibid.
20.  Ibid, pg. 4-16.
21.  Ibid, pg. 4-18.
22.  Information provided by F. X.. Barr, Graymtlls Co.,  Chicago, by telephone
     to J. L. Shuroakfir, EPA, January 13, 1977.
23.  Information provided by K. S. Surprenant, Dow Chemical,  Midland, Michigan
     by telephone to J. L. Shumaker, EPA, January 11,  1977.
24.  Information provided by Hydroscience, Inc.,  Knoxville,  Tennessee by
     telephone to J. L. Shumaker, EPA,  March 24,  1977.
                                        3-38

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                         4.0  COST ANALYSIS

4.1  INTRODUCTION
4.1.1  Purpose
     The purpose of this chapter is to present estimated costs for applying
alternative emission control techniques in the metal cleaning, or deceasing
industry.  Cost data will be provided for hydrocarbon controls on cold
cleaners, open top vapor degreasers, and conveyorized vapor degreasers.
These cost data will be presented  for model new facilities as well as for
model existing plants.
4.1.2   Scope
     With regard  to  cold cleaners, control cost estimates will reflect  the
use of  the  following techniques:
      1.   drainage facility;
      2.   mechanically  assisted cover (spring  loaded).
The scope of this section  includes both low  volatility  solvents,  such  as
mineral  spirits,  and high  volatility solvents such as  1,1,1-  trichloroethane.
 Costs  will  be presented for only one size cold cleaner  facility.
      No incremental  costs  for housekeeping controls are presented in this
 chapter.  A reasonable judgment is that such costs are negligible, particularly
 considering that they are offset  by savings in recovering additional solvent
 from improved housekeeping.
      With regard to open top  vapor degreasers, control  cost estimates will be
 presented for two sizes of facilities that primarily use trichloroethylene
 solvent or 1,1,1-trichloroethane  solvents.  The control cost estimates will
 reflect the  following  techniques:
                                  4-1

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     1.  use of a manual cover;
     2.  use of a manual or powered cover in combination with extended freeboard;
     3.  refrigerated chiller;
     4.  carbon adsorber;
     As in the case of cold cleaners, incremental  costs for housekeeping
controls on open top vapor degreasers are not presented because they appear
to be negligible.
     With regard to conveyorized vapor degreasers, control  cost estimates
will be presented for facilities that primarily use trichloroethylene or
perchloroethylene solvents.  The control cost estimates will reflect the use
of the following techniques:
     a.  carbon adsorber
     b.  refrigerated chillers
     Again, incremental costs for housekeeping are not presented because they
appear to be negligible.
4.1.3  Model Plants
     Control cost estimates are presented for typical model degreasers in the
metal cleaning industry.  Specific model plant parameters will be presented
in the subsequent portions of this chapter.  Admittedly, control costs may
vary from one installation to another, perhaps even appreciably from the
costs described for the models in this chapter.  However, the difficulty of
obtaining actual plant control costs requires use of model  plants.  To the
extent possible, EPA has incorporated actual plant cost information into the
cost analysis.
                                4-2

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     Cost information is presented both for typical  new model  degreasers as
well as for typical existing model facilities.  Model degreasers depicting
size, design, and solvent usage have been developed.  The purpose of this
is to show the relative variation in control equipment costs with these
factors.  Although the degreaser models chosen for the analysis are believed
to  be representative  of degreasers used throughout the industry, no attempt
has  been  made to  span the  range of existing degreaser designs and sizes.
4.1.4   Capital  Cost  Estimates
      Control  cost estimates comprise installed  capital  costs  and annualized
 operating costs.   The installed  capital  cost  estimates  reflect  the  cost of
 designing, purchasing,  and installing a particular control  device.   These
 estimates include costs for both major and auxiliary equipment, rearrangement
 or removal of any existing equipment, site preparation, equipment installation
 and design engineering.  No  attempt has been made to include costs for lost
 production during equipment  installation or start-up.  For degreasing operations,
 most of  the  controls discussed will take a matter of hours for installation
 which  should minimize delays in  production.  All capital costs reflect first
 quarter  1977 costs.  In general, information for capital costs has been
 developed through contacts with  degreaser  equipment manufacturers.   In addition,
 an EPA contractor study1  and EPA in-house  files  have  been  used to  develop the
  capital  costs.
  4.1.5  Annualized Costs
       Annualized cost estimates include costs for operating labor,  maintenance
 .and utilities, credits for  solvent recovery, depreciation, interest, adminis-
  trative overhead, property  taxes, and insurance.  Operating cost estimates
                                  4-3

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have been developed on the basis of the EPA contractor study cited above.
The number of annual  operating hours was assumed to be 2250 hours.  The cost
                                                        2
of electricity is assessed at 4 cents per kilowatt-hour.    Solvent prices
used were $0.20 per kilogram for mineral spirits, and $0.43 for trichloro-
ethylene and $0.41 for the chlorinated blended solvent used in cold cleaning.
These solvent prices are based on recent quotations from the Chemical
Marketing Reporter.3  Maintenance costs for all  controls (except housekeeping)
were estimated to be 4 percent of the purchase cost of the equipment.   Estimates
of depreciation and interest costs have been developed by EPA based on the use
of the capital recovery factor, an interest rate of 10 percent, and an equip-
ment life of 10 years.  In addition to costs for depreciation and interest,
other capital charges include a 4 percent charge for administrative overhead,
property taxes,  and  insurance.
4.2  COLD CLEANERS
4.2.1  Model Plant Parameters
     The model parameters that were used in developing control costs for cold
cleaners are shown in Table 4-1.  These parameters are based on industry
contacts and EPA studies  of the solvent degreasing industry.  The most common
type of  cleaning is  represented by  low  volatile  solvent  cleaning.  Also shown
is  high  volatile solvent  cleaning,  which is important  from  the standpoint  of
higher emission  rates.  The emission  rates  in Table  4-1  represent typical
values.   The  recovered  solvent values and  the cost of  solvent  are used to
estimate solvent credits  which will  reduce the  annualized  control costs.   The
assumed  composition  for the  high  volatility solvent  blend  is  60  percent
1,1,1-trichloroethane,  20 percent xylene,  and 20 percent mineral  spirits.
                                  4-4

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                            Table 4-1.   COST PARAMETERS FOR MODEL COLD CLEANERS
	 ,

Working Area, m
Solvent Used
Uncontrolled Emission Rate,
metric tons per year
Emission Rate with House-
keeping Requirements,
metric tons per year
f Solvent Recovered by Control
011 System, metric tons per year
Solvent cost, $ per kg
Low Volatility
Solvents
0.5
Mineral Spirits
0.25

0.16


U.024

0.20
High Volatility
Solvents
0.5
Blended Solvent
0.40

0.32


0.096

0.41
Source:  EPA assumptions based on  industry  contacts,  contractor  studies  and  in-house  files

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4.2.2  Control  Costs
     Costs for control  of emissions from cold cleaners  have been developed
for the following cases for model  new and existing cold cleaners:
     1.  drainage facility for low volatility solvent cleaning
     2.  drainage facility plus a mechanically assisted cover for high
         volatility solvent cleaning.
The drainage facility consists of an external rack equipped with a drain
line to return recovered solvent to the storage tank, which supplies the
solvent for cleaning.  The mechanically assisted cover consists of a spring
loaded plunger which helps the operator to easily open and close the cover.
     The costs for these equipment features are presented in Table 4-2.
Estimates are presented for installed capital costs, annualized costs, and
the cost per kilogram of hydrocarbon controlled.  The capital costs for the
drainage facility are the  same for an existing cleaner as for a new one
because of the ease with which it can be retrofitted.  The capital costs
for the cover are for the  spring loaded plunger which can be retrofitted
onto the  cover of an existing  cleaner.  These costs were provided to  EPA  by
a  manufacturer of cold  cleaning equipment.4'5  One hour of labor  is assumed
as the requirement  for  installing  the spring  loaded  plunger.
     The  cost  of hydrocarbon  control  per  kilogram of recovered  solvent is
quite  sensitive  to  the  value  of  the  recovered  solvent.  Note  that the low
volatility solvent  cleaner in Table  4-2 incurs a  cost  of $0.021  per kilogram
whereas  the high volatility solvent  cleaner saves $0.31 per  kilogram  for  the
 new  facility and $0.267 per kilogram for the existing  facility.
                                  4-6

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                                          Table 4-2.  CONTROL COSTS FOR TYPICAL COLD CLEANERS
                                                           (Vapor to Air Area of 0.5m2)
 I.   Model  New Facilities

     Installed Capital  ($)

     Direct operating costs  ($/yr)
     Capital  charges  ($/yr)
     Solvent cost (credit)  ($/yr)
     Annualized cost  (credit)  ($/yr)
     Controlled emissions  (metric  tons/year)
     Cost (credit),  $ per  Kg  controlled
II.   Model  Existing Facilities
     Installed capital ($)
     Direct operating costs ($/yr)
     Capital  charges ($/yr)
     Solvent cost (credit)  ($/yr)
     Annualized cost (credit)  ($/yr)

     Controlled emissions (metric  tons/year)

     Cost (credit), $ per Kg controlled
                                                                  Low Volatility Solvent
   25

 1.00
 4.30
(4.80)
 0.50
 0.024
 0.021
   25

 1.00
 4.30
(4.80)
 0.50

 0.024
 0.021
                                     High Volatility Solvent
    45

  1.80
  7.72
(39.36)
(29.84)
  0,096
 (0.31)
    65

  2.60
  11.15
 (39.36)
 (25.61)

  0.096
  (0.267)
 Source:Reference 4, 5 for estimates of capital  and annualized costs

-------
4.3  OPEN TOP VAPOR DE6REASERS
4.3.1  Model Plant Parameters
     The model parameters that were used in developing control  costs for
two sizes of open top vapor degreasers are displayed in Table 4-3.   The
two sizes represented are characterized by working area and solvent emissions.
These parameters were selected as a result of industry contacts and EPA studies
of the industry.  The emission rates in Table 4-3 represent typical values.
The working area is used to determine costs for covers, refrigerated chillers,
and freeboard extensions.  The assumption used to estimate costs is that the
length of the working area is twice the width.  The recovered solvent values
and the cost of solvent are used to estimate solvent credits which are deducted
from the annualized costs of the control devices.
4.3.2  Control Costs
     Costs for control of emissions from open top vapor degreasers have been
developed for the following cases for model new and existing degreasers:
     1.  manual cover;
                                                                 2
     2.  manual or powered cover for working area exceeding 1.0 m  in
         combination with extended freeboard;
     3.  refrigerated chiller;
     4.  carbon adsorber.
     Table 4-4  presents  the costs for these controls on the average sized
degreaser, and  Table 4-5  presents costs for the smaller degreaser.  Costs
are  presented  in terms of installed capital costs, annualized costs, and the
cost per kilogram of hydrocarbon controlled.
                                    4-8

-------
                       Table  4-3.  COST PARAMETERS FOR MODEL OPEN TOP VAPOR DEGREASERS
Working Area, m
Uncontrolled Emission Rate,
  metric tons per year
Emission rate with housekeeping
  requirements, metric tons per year
Solvent recovered by control system,
  metric tons per year
  a) Manual  cover
  b) High freeboard and
     powered cover
  c) Chiller
  d) Carbon  adsorber
 Solvent Cost, $ per kg
                                                       Typical Degreaser
1,67
9.5

6.7
 2.0
 2.7

 3.0
 3.3

 0.43
aser

Small
(
0.83
4.75

3.35
 1.0
 1.35

 1.50
 1.65
(D
                                                                                             0.43
     Manual  cover and  high  freeboard.
    SOURCE:   EPA  assumptions based on industry contact, contractor studies, and in-house files,

-------
Table 4-4.   CONTROL COSTS FOR TYPICAL SIZE OPEN TOP VAPOR DEGREASER
                        (Vapor to Air Area of 1.67
                                                                                       VA
                                                                                     irK)
Control Technique
I. Model New Facilities
Installed capital ($)
Direct operating cost ($/yr)
Capital charges ($/yr)
Solvent cost (credit) ($/yr)
Net annuali zed cost (credit) ($/yr)
Controlled emissions (metric tons/yr.)
Cost (credit) per Kg controlled
II. Model Existing Facilities
Instal led capital ($)
Direct operating cost ($/yr)
Capital charges ($/yr)
Solvent cost (credit) ($/yr)
Net annualized cost (credit)
($/yr)
Controlled emissions (metric tons/yr.)
Cost (credit), $ per Kg controlled
Manual
Cover

250^
10
43
(860)
(807)
2.0
(0.404)

aooW
10
51
(860)
(799)
2.0
(0.40)
Carbon
Adsorption

7400 ^
451
1268
(1419)
300
3.3
0.091

10,300^
451
1,765
(1419)
797
3.3
0.242
Refrigerated
Chiller

4900 ^3^
259
840
(1290)
(191)
3.0
(0.064)

6500^3^
259
1115
(1290)
84
3.0
0.028
Extended Freeboard
. 	 « ruwcreu l/over
• — • — — — . 	
2500 (4)
100
430
(1161)
(631)
2.7
(0.234)

8000(*,2)
100
1372
(1161)
311
2.7
0.115
(2)   Reference 1
 3)   Reference 1
 4)   References 7 and 8.

-------
Table 4-5.  CONTROL COSTS FOR SMALL OPEN TOP VAPOR DEGREASER
                      (Vapor to Air Area of 0.8 m^)

Control Technique 	 	
T MnHpl New Facilities
Installed capital ($)
Direct operating costs ($/yr)
Capital charges ($/yr)
Solvent cost (credit) ($/yr
Net annualized cost (credit)
($/yr)
Controlled emissions (metric
tons/yr.)
Cost (credit), $ per Kg
controlled
II. Model Existing Facilities
Installed capital ($)
Direct operating costs ($/yr)
Capital charges ($/y>")
Solvent cost (credit) ($/yr)
Net annualized cost (credit)
• ($/yr)
Controlled emissions
(metric tons/yr.)
Cost (credit), $ per Kg
controlled
(1 ) Reference 7.
(2) Reference 1
(3) Reference 1
(4) References 7 and 8.
Manual
Cover
_- 	 — 	
230^
9
40
(430)
(381)
1I"»
.0
(0.381)

270^
9
(430)
(375)
1 0
1 • V
(0.375)





Carbon
Adsorption

7400(2)
404
1268
(710)
962
1 65
1 « U>^
0.583

10,300(2)
404
1,765
(710)
1,459
1.65

0.884





Refrigerated
Chiller

2700 (3)
158
463
(645)
(24)
1.5

(0.016)

4030 ^
158
691
(645)
204
1.5

0.136





Extended Freeboard
and Manual Cover

430 (4)
17
74
(581)
(490)
1.35

(0.363)

570 (4)
17
98
(581)
(466)
1.35

(0.345)






-------
     With regard to Tables 4-4 and 4-5, the installed capital for the carbon
adsorber in the existing facility represents the worst retrofit situation
to be encountered for this control device.  This would occur if no steam
capacity is available for solvent desorption, and space is limited.  Retrofit
capital would include a small steam boiler and an elevated platform to provide
space.  For most retrofit situations, the installed capital would be somewhere
between the costs for a new facility and the estimates shown for the existing
facilities.
     The retrofit factor for carbon adsorbers applied to existing degreasers
was developed from an actual facility.6  The cost of the carbon adsorber for
the facility was $13,990; the boiler, $4,000; and the platform above ground
level  in the plant to house both  the boiler and the adsorber, $3,300.
The ratio of the boiler and platform costs to the carbon adsorber costs  is
approximately 0.50.
     The retrofit factor  for the  refrigerated chillers is  also approximately
50 percent, or  in other words,  retrofit  costs are 50 percent more  for  existing
degreasers  than for  new units.  The basis  for this  is the  study cited  earlier
 (see  reference  1).
      Retrofit costs  for freeboard extensions, or  high freeboards,  and  covers
are difficult  to determine in  some situations.   Based  on  contacts with  two
manufacturers  of these  devices, approximate  installation reouirements  are
 10 man-hours  for manual  covers,7  16  man-hours  for freeboards,  and  16 man-hours
                    8
 for  powered covers.
      The installed capital  in Table  4-4 for the powered  cover  with extended
 freeboard in an existing  facility includes $5,5009 for digging a concrete
 pit.   The purpose of the pit is to allow room for a hoist or a conveyor
                                  4-12

-------
bringing parts to the cleaner.  Such a problem most likely would not exist
for small degreasers.  Consequently, a provision for this type of retrofit
penalty is provided in Table 4-4 but not in Table 4-5.
     Another difference to be noted in capital costs for the powered cover-
extended freeboard design is  that the powered cover is required only for
this degreaser with working area in excess of 1.0 m2.  Otherwise, the
degreaser would  be required to  install only  a manual  cover.  Note the
difference  in capital  between the manual cover-extended  freeboard design
 in Table 4-5 and the powered  cover  design  in Table 4-4 for new facilities.
      In both Tables  4-4 and  4-5,  the  costs of hydrocarbon control  per  kilogram
 of recovered solvent are reported.   These  values will be used  to develop the
 cost-effectiveness curves later in  this  chapter.  As these tables indicate,
 the costs of hydrocarbon control  vary considerably depending upon the size
 of the degreaser, the type of control, and the amount of recovered solvent.
 As an illustration, carbon adsorber costs range from $0.091 per kilogram
 (Table 4-4)  in  a new facility for the typical degreaser to $0.583 per kilogram
 (Table 4-5)  for the small degreaser.  This  is an indication that carbon ad-
 sorbers should  be much less  expensive for larger open top vapor degreasers.
 Conversely,  the extended freeboard and manual cover  combination is less expen-
 sive for the smaller degreasers than the  similar  combination  with the powered
 cover  on larger degreasers.  This conclusion  is  shown by  the  difference  in
 savings  between $0.234 per  kilogram  for the typical  degreaser in a new  facility
  (Table 4-4) and $0.363 per  kilogram  for the small  degreaser (Table 4-5).
                                   4-13

-------
4.3.3  Cost-Effectiveness
     The purpose of this section is to provide a graphical  analysis of the
cost-effectiveness of alternative control  options for various types of open
top vapor degreasers.  This analysis will  attempt lo relate the annualized
cost per kilogram of hydrocarbon removal  with degreaser size for each control
option.
     Figure 4-1  is a presentation of the  typical relationship for control  of
hydrocarbon emissions from open top vapor degreasers.   Curves are shown for
carbon adsorbers, refrigerated chillers,  powered covers with extended free-
boards,  and manual covers.  The size range shown in Figure  4-1  represents  the
approximate range of most degreasers (0.8 square meters to  18 square meters)
based on EPA data, contractor studies, and contacts with degreaser manufacturers.
The efficiencies of the control devices shown represent the capability of the
control  device for reducing emissions from a well maintained degreaser (which
has carried out all good housekeeping practices).  Although detailed costs
are  presented for two model degreasers in Section 4.3, several more estimates
were derived in order to define the curves with reasonable  precision.
     The curves represent the retrofit costs for existing facilities.  However,
this constraint was somewhat relaxed for the powered cover  option which does
not include the cost of the concrete pit shown in Table 4-4.  The reason for
this is that the powered cover option with a lower control  efficiency may
be an acceptable option in those situations where the concrete pit is not
necessary.  On the other hand, if the pit were required, then the refrigerated
chiller with a higher control efficiency (45 percent) becomes more attractive.
                                 4-14

-------
                        Cost (credit) per kg  Controlled ($)
ro
a>
-s
o
CD
a>

-------
 For example, Table 4-4 shows for the degreaser with 1.67 square meters a
 cost of $0.028 per kilogram for the chiller and $0.115 for the powered cover
 with the concrete pit.
     An important concept for control of degreaser emissions is the fact
 that credits for recovered solvent offset to some extent the annualized
 costs of installing, operating, and maintaining a control device.  In re-
 viewing Figure 4-1, the reader will observe the extent to which solvent
 credits can more than offset the annualized costs of the control  device.
 This is graphically illustrated by the horizontal dashed line of $0. per
 kilogram.   This dashed line indicates that application of carbon adsorbers
 will result in an out-of-the-pocket expense to the operator of the degreaser
 for a size below an approximate 6 square meters in working area.   Similarly,
 refrigerated chillers will do the same for degreasers smaller than approximately
 2 square meters.
 4.4  CONVEYORIZED DEGREASERS
 4.4.1   Model Plant Parameters
     The model  plant parameters that were used in developing control costs for
 conveyorized degreasers are displayed in Table 4-6 for monorail  and cross-rod
 designs.   These parameter selections are based on industry contacts and EPA
 studies of the industry,  in the same manner as cold cleaners and open top
 vapor degreasers.  The emission rates in Table 4-6 represent typical values.
The working area is used  to determine costs for refrigerated chillers.   The
 assumption used to estimate chiller costs is that length of the working area,
 or interface, is 2.7 times the width.  The basis for this is an emission test
 study performed on a monorail degreaser.   The recovered solvent values and
 the cost of solvent are used to estimate solvent credits which will reduce the
 annualized control costs  of the control devices.
                                   4-16

-------
                          Table  4-6.   COST PARAMETERS  FOR MODEL  CONVEYORIZED  DEGREASERS
               2
Working Area, m




Uncontrolled emission rate,                           35

   metric tons per year



                                                      26                                      10-5
Emission rate with housekeeping

   requirements, metric tons

   per year



                                                       13  1                                     ^'^'
Solvent recovered  by  control

   system, metric  tons  per year



                                                      0  43                                   °'43
Solvent cost,  $ per kg

                                                        	___	——	—	



 Source:   EPA assumptions based on industry contacts, contractor studies and in-house files.

-------
4.4.2  Control Costs
     Costs for control of emissions Prom conveyorized degreasers have been
developed for the following control devices:
     1.   carbon adsorbers
     2.   refrigerated chillers.
     Table 4-7 presents the costs for the model  conveyorized degreasers.
Costs are presented in terms of installed capital  costs, annualized costs,
and the cost per kilogram of hydrocarbon controlled.   The installed capital
for the carbon adsorber in the existing facility represents the worst retrofit
situation to be encountered.  This would occur if no steam capacity is available
for regeneration of adsorbed solvent and space is limited.  Retrofit capital
includes a small steam boiler and an elevated platform for the carbon adsorber.
The retrofit factor applied to the new source costs for the carbon adsorber
is the same as the retrofit factor used for open top vapor degreasers.
     Most existing facilities already have steam raising capacity to operate
a still  to reclaim dirty solvent.  These facilities could possibly schedule
their steam boiler to desorb the carbon bed during periods when the still is
not used.  For most retrofit situations, the installed capital would lie
somewhere between the costs shown for new and existing facilities.
     The figure of $8,550 shown for the existing facility on the monorail
degreaser compares reasonably well with a figure of $8,294 (1975 dollars) on
an actual facility.    The latter would be $9,123 in 1977 dollars based on the
use of the Chemical Engineering Plant Index.  The retrofit factor used to
estimate costs for chillers is the same as the one used for the chillers on
open top vapor degreasers.
                                    4-18

-------
                                     Table 4-7,  CONTROL COSTS FOR TYPICAL CONVEYORIZED DEGREASERS
                                                       (Vapor to Air Vapor Area.of 3.8 m?)
                                                                 Monorail  Degreaser
                                                                                                         Cross-Rod  Degreaser

Carbon
Adsorber
Refrigerated
Chi 1 ler 	
Carbon
Adsorber
Control T6chm Qti6_ — 	 . 	 — — — •• • •-• - • 	 — •••• 	 - ~
I. Model New Facilities





II.




Installed capital ($)
Direct operating costs ($/yr)
Capital charges ($/yr)
Solvent cost (credit) ($/yr)
Annualized cost (credit) ($/yr)

Controlled emissions (metric
tons/yr.)
Cost (credit), $ per Kg controlled
Model Existing Facilities
Installed capital ($)
Direct operating costs ($/yr)
Capital charges ($/yr)
Solvent cost (credit) ($/yr)
Annual i zed cost (credit) ($/yr)
Controlled emissions (metrft tors/yr]
Cost (credit), $ per Kg controlled
1 1 ,800
970
2,024
(5,633)
(2,639)
1O 1
10. 1
(0.201)

17,600
970
3,020
(5,633)
(1,638)
13.1
(0.125)
5,725
430
982
(5.633)
(4,221)
101
I J * 1
(0.322)

8,550
430
1,466
(5,633)
(3,734)
13.1
(0.285)
11,800
754
2,024
(2,258)
520
5.25

0.100'

17,600
754
3,020
(2,258)
1516
5.25
0.289
Refrigerated
Chiller

5,000
334
858
(2,258)
(1,066)
5.25

(0.203)

7,460
*3O A
334-
1,279
(2,258)
(646)
5.25
(0.123)
Source:Reference 1 for estimates of capital  and  annualized  costs.

-------
     The cost of hydrocarbon control  per kilogram shown  in  Table 4-7 for
the carbon adsorber on a new facility costs $0.10 per kilogram for the cross-
rod degreaser.  On the other hand, the application of a  carbon adsorber results
in a saving of $0.201  for the monorail degreaser.  On the retrofitted facility,
the application of the carbon adsorber costs $0.289 per  kilogram for the cross-
rod degreaser but results in a savings of $0.125 for the monorail degreaser.
It must be noted that the difference in cost for the two degreaser models
is sensitive to the emission rate and potential solvent  recovered because the
annualized costs of installing and operating a carbon adsorber are assumed to
remain approximately the same in both cases.  This is an important consideration
in the impact of control upon the owner of the degreasers.
     The  refrigerated chiller appears to be inexpensive to the user regardless
of the type of degreaser and the degree of retrofit.  This is demonstrated by
the savings shown  for all cases in Table 4-7.
4.4.3  Cost-Effectiveness
     This section  provides  a graphical  analysis  of the cost-effectiveness
for alternative control  options on conveyorized  degreasers.   This analysis will
relate  the annualized cost  per  kilogram of  hydrocarbon control  to degreaser
size  for  each control option.
      Figure 4-2  shows a relationship of cost  versus  size for  carbon  adsorbers
and  refrigerated  chillers  on monorail  degreasers.  The  assumptions  regarding
the  size  range and control  efficiencies are similar  to  those  outlined for open
top  degreasers.   The  size  range of most monorail degreasers  is  1.9  to 18
 square meters.  As shown in Figure 4-2, the application of carbon adsorption
 results in an out-of-the-pocket expense for degreasers  smaller than approximately
 2 square meters in working area.   By the  same token, carbon  adsorbers can
                                   4-20

-------
•o

-------
be quite cost-effective for degraasers with Urge air to vapor working areas.
     Figure 4-3 shows a similar relationship for cross-rod cisare^ssi-s.  There
are two important differences between Figure 4-3 a'-vi Figure ^-2  fcr  ihe
monorail ctegreaserL,  Flr^t, the si7?, i'^nqc- ~s ?.*\-v .,:s-r  ;ro»" ?;fre  cross-rod
degreasers.  The rsnye for most cros^-rod '-i^r-na^rs 1?,  !.<;• square rr/ate'-1."  to
4c8 square meters.  For- moncrel'1 oec-easert. vh« rang^ is 1.9 to  '8 cq.-arc
meters.  Seconds controls are generally mere expensive for cross-rod degressars
than for moncrail degreasers.  in particular,the cost of carbon  adsorption
appears to be more than offsetting solvent credits along the entire  size range.
This is shown by the position of the carbon adsorption curve in  relation to
the horizontal line of $0. per kilogram control in Figure 4-3.   The  information
depicted in the two figures for monorail and cross-rod degreasers demonstrates
the variation in costs with degreaser design that can be anticipated for
conveyorized degreasers.
                                  4-22

-------
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               o
                       CO
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                               Cost  (credit)  per kg  Controlled ($)
                                I
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-------
 4.6   REFERENCES

 1.   Surprenant,  K.S., and Richards, D.W., "Study to Support New Source
     Performance  Standards for Solvent Metal Cleaning Operations" prepared
     for  the  Environmental Protection Agency, Contract No. 68-02-1329,
     Dow  Chemical Company, Midland, Michigan, June 30, 1976.

 2.   Anon., "Typical Electric Bills 1976," Federal Power Commission.

 3.   Chemical Marketing Reporter, Schnell Publishing Co., March 7, 1977.

 4.   Private  communication, Frank L. Bunyard, OAQPS, Environmental Protection
     Agency,  to Jerry Shields, Manager of Marketings Graymills, Chicago,
     August,  1976.

 5.   Private  communication, Frank L. Bunyard, OAQPS, Environmental Protection
     Agency,  to Jerry Shields, Manager of Marketing, Graymills, Chicago,
     August,  1976.

 6.   Surprenant and  Richards, OJK cit.,  Appendix C-4.

 7.   Private  communication, Frank L. Bunyard, OAQPS, Environmental protection
     Agency to Parker Johnson, Vice President of Sales, Baron  Blakeslee Corp.,
     Cicero,  Illinois, March  16, 1977.

 8.   Private  communication, Frank L. Bunyard, OAQPS, Environmental Protection
     Agency to Dick  Clement,  Detrex Chemical, Detroit, Michigan, March  21,  1977.

 9.   Surprenant and  Richards, 0£. cit..  page 4-97.

10.   Surprenant and  Richards, op_. cit.,  Appendix C-7.

11.   Ibid.,  page  10.
                                    4-24

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             CHAPTER  5.   ADVERSE  ENVIRONMENTAL  EFFECTS
                     OF  APPLYING  THE  TECHNOLOGY

5.1   AIR IMPACTS
     No significant adverse air impacts should  result from solvent degreaslng
regulations, although gross negligence with maintenance and operation of
control devices could increase emissions in individual  cases.   Examples are
carbon adsorption systems operating with spent or saturated adsorbent,
maladjusted refrigeration systems and excessive ventilation rates.  Proper
maintenance and operation of these controls will eliminate increases and
effect significant reductions in emissions.
     Improper  incineration of waste solvent is another possible area where
emissions could increase.  If chlorinated waste solvents are incinerated
without subsequent gas  cleaning, hydrochloric acid,  chlorine, phosgene and
other  potentially harmfully emissions  could result.  Sophisticated gas cleaning
equipment is  required to control these emissions.
     Boiler emissions may increase due to  the  steam  required to distill waste
solvent and regenerate  carbon  beds,  but in general these  increases will be
insigificant compared to the emission  reductions obtained  by this equipment.

 5.2  WATER  IMPACTS
 5.2.1   waste Solvent Disposal
      The major potential water pollutants  from solvent degreasers are waste
                                  5-1

-------
 solvents.  Waste solvent can enter natural  water systems  through  sewer
 disposal  or as leachate f-om landfills,   Additional  air pollution control?
 are not expecteo to allow sewer or improper landfl'l  disposal  because  much
 of the solvent would eventually evaporate.   Thus, water pollution would
 probably  be diminished by additional  air pollution  control.
 5.2.2  Steam Condensate from Carbon Adsorption
      The  largest impact on water quality resulting  from the  control  of solvent
 metal  cleaning comes from the use of  carbon  adsorption.   Steam used  to desorb
 the solvent is condensed with the solvent and separated by gravity.  Water
 soluble stabilizers* and some solvent will  remain with  the water  and eventually
 enter the sewer system.
      Stabilizers are organic  chemicals added in very small quantities  to
 chlorinated solvents  to  protect  them from decomposition.  Stabilizers
 evaporate  from the  degreaser  as  does the  chlorinated solvent and  both  are
 amenable  to  collection by  adsorption.   Furthermore,  many stabilizers are
 water miscible  and  thus will  be  removed almost completely from the process
 during steam desorption.   Chlorinated solvents are only slightly water
 miscible but small quantities will remain with the water.
 5.2.2.1  Chlorinated Solvent in Steam Condensate -
     Solvent discharge into the sewer can typically  reach  190 kg (0.13 m3 or
 35 gallons) per year.  This assumes solvent  at a concentration  of  900 ppm in
 the condensate and a total of about 40,000 gallons per year of  steam condensate.
*
 Stabilizers may also be referred to as  inhibitors  or additives    Some
.stabilizers are normally lost into  the  water of the  degreaser1s  water
                                   5-2

-------
In comparison,  the  reduction  in  atmospheric  emissions  from  the  degreaser  by
using the carbon adsorber would  typically be 14,000  kg (10  m3 or  2500  gallons)
per year.  Therefore, in this case potential sewer emissions of solvent
(before evaporating) are less than about 1.5 percent of the degreaser  emissions
prevented by the carbon adsorber.  The above estimates are  based  on two tests
which measured the solvent content in waste water from adsorbers  used  on
                     1 2
chlorinated solvents.  *
5.2.2.2.  Stabilizers  in Steam Condensate -
      In  addition to  chlorinated  compounds,  steam condensate will  contain small
amounts  of solvent stabilizers.  When the condensate  is disposed of most of
these stabilizers,  because of their  volatile nature,  will  eventually  evaporate
      The highest sewer stabilizer  emission  would probably  occur with  1,1,1-
trichloroethane which  requires  considerable amounts of water soluble  stabilizers.
Assuming a  solvent  recovery  rate of  10  m3 per year  (2500 gallons per  year),
 5 percent stabilizers  in the 1,1,1-trichloroethane  blend and 40  percent  of  the
 stabilizer being water soluble, the  stabilizer  effluent to the sewer  would  be
 0.2 m3 per year (50 gallons  per year).   This would be the  worst  case; however,
 and it may not be  representative of  any actual  degreasing  processes.   The
 captured solvent vapor does  not necessarily contain as high a  precentage of
 stabilizers as does the original liquid solvent.   For this reason  even systems
 using 1,1,1-trichloroethane may not emit this  amount.  Furthermore, other  major
 solvents contain less water soluble stabilizers than 1,1,1-trichloroethane;
                                                                    3
 therefore, the average stabilizer emission would be  less than 0.2  m  per year.
       A  method  for assessing the impact of  the stabilizers would be to analyze
  the  toxicity,  water solubility, percent composition,  volatility, and BOD
  (relates to the decomposition  rate) for each stabilizer.  Unfortunately,
  percent compositions  are generally  considered trade  secrets by solvent
                                      5-3

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manufacturers.  However, a literature search yielded some data which is given
in Appendix B.6.2.
     After studying the effects of some of the more toxic substances, it was
concluded that only diisobutylene and triethylamine, which are used in
trichloroethylene, present any significant potential problem with regard to
              o
fish toxicity.   Two other stabilizers of possible concern are acrylonitrile
and epichlorohydrin, although the data on them are not yet conclusive.
     If the quantity of stabilizers and solvent dissolved in the steam
condensate were found to be significant, then air sparging could dramatically
reduce the levels of all these compounds.  During sparging it may be advanta-
geous to vent the off-gas back into the adsorber.  Thus, atmospheric emission
of the sparge off-gas would be controlled.  Furthermore, more stabilizer would
tend to remain in the recovered solvent.  Although sparging appears  to be an
inexpensive means of treating the waste water, the data thus far have not
indicated a significant environmental need.
5.2.3  Effluents  from Water Separators
     Water separators on vapor degreasers and distillation units collect a
small amount  of contaminated water.   This is generally  less than a  gallon or
two  per day per degreaser, and should not create  a  significant  impact  on wate.r
quality.   De-icing  of refrigerated  control  systems  which  operate below  32 F,
will increase this,  but probably  not  enough to create  a problem.   Steam
stripping  of  still  bottoms in  distillation  units  to reduce  solvent content  will
also increase this  amount, but again  probably  not enough to  create a problem.

5.3  SOLID WASTE  IMPACT
     There appears  to  be  no  significant" solid  waste impact  resulting from
control  of solvent  degreasers.   The* quantity of  waste  solvent would not increase
as  a result  of  controls but  should decrease because of increased practice of    *
                                   5-4

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distillation and incineration.
     Carbon used in carbon adsorber beds is discarded periodically.   Vendors
and users have estimated the life of carbon at up to 30 years but replacement
is generally recommended every 10 to 15 years.  Assuming there are up to
7,000 degreasers, using 50 kg of carbon each and averaging a 10 percent annual
replacement rate, disposal of carbon from adsorbers could reach 35,000 kg
annually for the nation.  This amount would never be realized, however, because
spent carbon can easily be reactivated.  Most major activated carbon manufacturers
are  equipped for this  task.

5.4   ENERGY IMPACT
      Carbon adsorbers, refrigerated chillers  and distillation units  are  the
 principal  energy consuming  control  devices  used  for  controlling  deceasing
 emissions.
      A carbon  adsorber consumes  the greatest  amount of enerav  because of steam
 required for desorption;  however,  this  energy expenditure is far less than  the
 energy required to manufacture replacement solvent.   A typical  carbon adsorption
 system on a degreaser may consume  35 kw (120,000 Btu per hour)  of energy and
 recover 7 kg per hour (15 pounds per hour) of solvent.  This energy consumption
 estimate is based on the following assumptions:  4 kw per kg solvent for steam
 production, 3 to 12 kw (10,000 to 40,000 Btu  per hour) for fan power.  A carbon
 adsorber may typically increase the energy consumption of a vapor deceasing
                      4
 system by 20 percent.
      A typical refrigerated freeboard chiller may increase a degreaser's energy
 consumption by 5 percent.  The chiller would consume  0.7 to 2.2 kw  (2500 to 7500
 Btu  per  hour)  if  it ran  at 100 percent output.  The above values are derived
 from assuming  an  average of 1 to  3 horsepower for compressor ratings.  A chiller
                                       5-5

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may reduce emissions by about 1.5 kg per hour (3 Ibs per hour) on a typical
                                       2
open top vapor degreaser having a 1.7 m  (18 square feet) opening.  Thus,
roughly 0.5 kw •  hr may be spent to save 1.5 kg of solvent.0
     Solvent- distillation requires about 0.1 to 0,2 kw hr/kg of recovered
solvent (150 to 300 Btu/pounri).  Assuming -  , ^aam cost o* 0,78 cents/kwhr
          F
(2.30 $/10  8ti!,'s than the euer.;,/ costs r,i)e lo •: '!5 ,;/k;.j of Stilled soU'erif
(0.035 to 0.07 cj/lb).   Considering that c.h'sorinated solvent cost? about 45
tf/kg (20 <£/lb), the cost of the distillation energy appears to be an insignifican
expenditure.
     Other vapor control  devices are the powered cover and powered hoist.
Their energy consumption is insigificant because the electric motors are small
and are used only for short durations.
     The energy value of the solvent saved is much greater than the energy
expended to conserve the solvent.  The energy value of the solvent is composed
of the solvent manufacturing process energy plus the heat of combustion lost
when the processed petroleum feedstock is not used as fuel, plus other energy
consumed to replace the lost solvent.  The heat value of the feedstock alone
is greater than the energy required to recover the solvent.  Without doubt
control of solvent emissions, by any method, would have a favorable impact on
energy consumption.

5.5  OTHER ENVIRONMENTAL CONCERNS
     The only other consideration might be blower noise associated with carbon
adsorbers.  This noise does not affect the environment external to the plant,
although it would be noticeable inside the plant near the adsorber.  Noise levels
have not been measured because they have not appeared significant when compared
to the normal noise level in machine shops and other manufacturing areas where
                                                                                4
                                      5-6

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carbon adsorbers are found.   While noise does not seem to present a
significant environmental  problem, it is worthy of consideration when
choosing the in-plant location for a carbon adsorber.  This problem could
be resolved by utilizing existing noise suppression technology.
                                      5-7

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REFERENCES
1.  Scheil,  George W., Midwest Research Institute.   "Source Test
    Trichloroethylene Degreaser Adsorber,"   EPA Project Report No.
    76-DEG-l.
2.  Scheil,  George W.  "Test of Industrial  Dry Cleaning Operation,"
    EPA Report No. 76-DRY-2.
3.  Surprenant, K.S. and Richards, D.W., Dow Chemical.  "Study to
    Support New Source Performance Standards for Solvent Metal
    Cleaning Operations," Prepared for EPA, Contract No. 68-02-1329,
    Task Order No. 9.
4.  IBID.  pg. 7-8.
5.  IBID.  pg. 7-9.
6.  IBID.  pg. 7-9.
                                     5-8

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                  CHAPTER 6.  COMPLIANCE TEST METHODS
                       AND MONITORING TECHNIQUES

     It is  not expected  that  emission  testing will  play  a  significant part
in a compliance program  for degreasers.   This results from the  difficulty
in measuring emissions and  in enforcing  emission standards, as  discussed in
Chapter 7.   Instead, equipment and operating practice standards appear to be
more realistic options.   In these, compliance relies principally upon
observation to determine if control equipment is designed and functioning
properly and to ensure that operating practices, as observed under normal
conditions, are being properly followed.
     Although  the compliance emphasis should be on equipment and operating
practice standards, the emission  rate of a degreaser system may be useful
supplementary  information.   For example, if emissions are  greater than
average for a  system  of a certain size,  it  is an indication that the system
 is inadequately or  improperly controlled.   Emission  rates  can  be estimated
 roughly with  an analysis of  solvent purchase and inventory records and  more
 accurately with a material balance test.
      Other emission tests  that  could be useful  in  compliance  programs are
 tests for leaks and tests  of carbon adsorption off gas  streams.   The costs
 of these tests will often be offset by solvent savings  from reduced emissions.
 An investigator with some familiarity with degreasers and carbon adsorption
  systems can frequently identify  defective systems with a brief inspection and,
                                    6-1

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thus, avoid the expense of emission testing.

6.1   OBSERVATION OF CONTROL EQUIPMENT AND OPERATING  PRACTICES
     If the degreasing regulation specifies  equipment  and  operating
standards, the compliance test is basically  one of visual  observation.   The
observation control equipment and operating  practices  mainly involves checking
through a list of requirements; however,  a Basic understanding of degreasfng
systems is necessary.  The details to observe are described in Sections 3.1
and 3.2 of this report.

6.2  MATERIAL BALANCE
     A material balance test seeks to quantify the amount of solvent input
into a degreaser over a sufficiently long time period so that an average
emission rate can be calculated.  The major advantages of the material
balance method are:   (1) the total system is checked, (2) the test is simple
and does not require expensive, complicated test equipment, and  (3) records
are usually kept of  solvent use, and generally all solvent added is make-up
for solvent emitted.
     The disadvantage  of the material balance method  is that  it  is time
consuming.  Because  many degreasers  are  operated  intermittently  and  because
there  is  inaccuracy  in  determining liquid levels, an  extended test time  is
needed  to  ensure that calculated  emission rates  are true  averages.
      In order  to perform a material  balance test, the following  general
procedure should be  followed:
      1.  Fill  the  solvent  sump (or bath) to a  marked  level.
      2.  Begin normal  operation of the degreaser, recording the  quantity of
make-up solvent and  hours  of operation.
                                    6-2

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     3.   Conduct the test for about four weeks,  or until  the solvent loss is
great enough to minimize the error in measurement.
     4.   Refill the solvent sump to the original, marked level, recording
the volume of solvent added.  The total volume of solvent added during the
test period approximately equals the solvent emitted.
     Although a highly accurate material balance  is not usually necessary,
the following modifications will improve the accuracy of the test.
     1.   Clean  the  degreaser  sump before testing.
     2.   Record the amount  of solvent  added to  the  tank with a flow meter.
     3.   Record the weight  and type of work load degreased  each day.
     4.   At the end of  the  test run,  pump  out  the used  solvent and  measure
 the amount with a flow  meter.  Also,  approximate the volume of metal  chips
 and other material  remaining in the emptied sump, if significant.
      5.   Bottle a sample of the used solvent and analyze it to find the
 percent that is oil and other contaminants.  The oil and solvent proportions
 can be estimated by weighing samples of used solvent before and after boiling
 off the solvent.   Calculate  the volume of oils  in  the used solvent.  The volume
 of solvent displaced by this oil along with the  volume of make-up  solvent
 added during operations is equal to the solvent  emission.
      Proper maintenance and  adjustment should  be performed on the  degreaser
 and control system before  the  test period.

 6.3  OTHER EMISSION TESTS
      An emission measurement test on  the  off-gas stream from  a  carbon  adsorber
 may occasionally be necessary.  However,  this  has  value only  in  evaluating  the
  adsorption efficiency  not the control efficiency of the system.   This  test
  will  give no indication of the effectiveness of the adsorber's  collection
                                     6-3

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system; neither will  it guantify emissions  from waste  solvent evaporation,
leakage lossess carry-out or sump evaporation.
     The better sampling systems for organic solvents use gas chromatography
(GC).  Techniques for using GC are discussed in EPA-450/2-76-028,  "Control
of Volatile Organic Emissions from Stationary Sources.   Volume 1:   Control
Methods for Surface Coating Operations."  A specific method for perchloro-
ethylene is also detailed as EPA Method 23:  "Determination of Total Non-Methane
Hydrocarbons as Perch!oroethylene from Stationary Sources."  Finally, a method
for another chlorinated hydrocarbon is EPA Method 106:   "Determination of Vinyl
Chloride from Stationary Sources."  For stack measurments, velocity and flow
rate can be determined using EPA Methods 1  and 2.
     One EPA emission test measured carbon adsorber inlet and outlet concen-
trations both with a flame ionization detector and with a gas chromatograph,
using integrated gas-bag samples.  The methodology and test results are detailed
in EPA Project Report No. 76-DEG-l.                                             "
     Useful tools in locating leaks and other points of emission are the halide
torch and the Drager tube.  The halide torch is useful as a locating device
that will detect sources of halogenated hydrocarbon vapors.  The Drager tube
will quantify the vapor concentration in ppm and is useful in survey work.
These should be useful and relatively inexpensive means to locate sources and
quantify by magnitude the hydrocarbon loss.  They would allow a maintenance
check of control equipment operation and prevent inadvertent losses.
                                    6-4

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                    CHAPTER  7.   ENFORCEMENT  ASPECTS

     Emission  standards  are  generally not practical  to  enforce  for  solvent
degreasing for three reasons:   (1)  there is  an  extremely  large  number of
solvent degreasers, (2)  emission tests are time consuming,  and  (3)  there
are complexities in specifying acceptable emission rates.   In order to
avoid use of emission standards and to provide  quick,  inexpensive compliance
testing, equipment and operational  standards are recommended.
     Even though visual  inspection is relatively quick and inexpensive, it
can not easily determine whether or not the equipment and operation is in
compliance.  For example, on cold cleaners it must be determined whether
or not it is practical to install an  internal drainage facility.  Also, for
highly volatile solvents in cold cleaners, one must decide whether or not
the cover can be classified as  easily operable.  Another example is in
deciding what is significant liquid  carry-out.  Even though  Chapters 3 and 6
give background on  making decisions  for visual  inspection, the  inspector
still  needs an  adequate background knowledge of degreasing operations to deal
with some of  the less definite  aspects  of enforcement.
     Because  most  emission  controls  serve to reduce the emissions  inside the
plant, it is  reasonable to  consider  combining  enforcement  by OSHA  and  EPA  for
 control  of  solvent degreasers.   The  possibilities of  a cooperative enforcement
 program with  OSHA  and EPA are being  explored.
                                     7-1

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7.1  REGULATORY APPROACHES
     There are four types of regulations which can be considered for solvent
metal cleaning:  (1) emission standards, (2)  equipment specification
standards, (3) operational requirement standards,  and (4)  solvent exemption
standards.  Equipment and operational  standards appear to  be superior to
either emission standards or solvent exemption standards.   Each of these
approaches is discussed in the following sections.
7.1.1  Emission Standards
     Emission standards require an emission measurement.   A material balance
is the most accurate measurement method for compliance testing but could
require over a month for one test.  If solvent consumption records kept by
the degreasing operator are accurate and complete, they could satisfy the
requirement for a material balance test.
     If enforcement were only to determine whether or not  degreasing systems
are designed properly, then one emission test would be sufficient for each
degreaser model.  However, adjastment, maintenance, and operation of degreasers
varies so greatly that the actual level of emission control cannot be expected
to be similar, even for identical degreaser models.  Thus, individual degreasers
rather than models must be evaluated.
     An emission standard may be a simple emission rate or it may be related
to another variable, such as work load tonnage, heat input, idling mode
emission  or uncontrolled emission rate.  The three most reasonable alternatives
for  emission  standards are:   (1)  simple emission rate, (2) emission rate per
open area of degreaser and (3) emission rate per work load tonnage.  These
alternatives are briefly discussed below.
     The  simple emission rate standard provides a conventional regulation
                                   7-2

-------
that is readily understood.   However,  different  values  of  acceptable emission
rates would have to be provided for each type of degreaser.   It  would  also
not be reasonable to require the same emission rate for large degreasers  as
for small degreasers; this would require an emission rate based  on the open
area of the degreaser.
     Although emission rate is related to the area of the air/vapor interface,
an important consideration is the amount of work load processed.  Thus, possible
improvement to an emission standard would be to relate it to the work tonnage,
for example, a specified amount of solvent emission could be allowed per ton
of work  load cleaned.  This  type of standard would be  particularly useful if
the work  loads were  consistent in  their surface-to-weight ratio and their
 tendency  to entrain  solvent; however,  this  is rarely the  case.  For example,
 deceasing a ton of hollow rivets  would result  in much greater  solvent
 emissions than would degreasing a  ton of cannon balls.
      Generally, for an emission standard to apply fairly to all degreasing
 applications, it must relate to the amount and type of work load.  Preferably,
 the emission standard should also consider the type of degreaser  and its size.
 Even  if  an emission standard could be  devised to satisfy these requirements,
 it would be difficult to enforce and very burdensome for degreasing operators
 to have  to record quantities and types of prrts cleaned.
  7.1.2 Equipment Standards
       Equipment  standards  can  be easily enforced  and fairly  applied to the large
  variety  of degreasing applications.   Equipment standards would not require
  the same performance by a degreasing operation with a large work load as that
  with a small  work load.
       The equipment requirement must be specific enough to  ensure effective
  control but not so restrictive that it would discourage new control  technology.
                                       7-3

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For example, the high freeboard,  refrigerated chiller,  and carbon adsorption
ventilation rate can be specified to ensure sufficient  emission control.
The specifications usually represent an engineering judgement by experts  in
the degreasing fields and could be revised as new test  data are collected.
Another type of specification for control  equipment is  the exemption of
degreasers that are too small for control  equipment to  be economically
reasonable.  Particularly in the case of refrigerated chillers and carbon
adsorbers, installation could be too expensive for small degreasers and could
even cost more than the degreaser itself, thus, a lower level cut-off of
                 P
approximately 1 m  for open top vapor degreasers is recommended.  Because
of  the continuing developments in emission control for solvent degreasing,
provision must be made to approve control systems that do not satisfy the
requirements  specified in this document but may still be effective.  Section
3.2 describes equipisent  and operational  standards that can  be  formulated.
7.1.3  Operational  Standards
     As  with  equipment standards, operational  standards can  apply  to almost
 all degreasing  applications, regardless of their  size  and  type  of  work load.
 Operators  will  play a key role in achieving  emission control;  however, they
 will  have  little incentive  to  follow complex standards.   Thus,  the standard
 must be  simple,  understandable,  and precise.   The numerous  operational
 requirements  can be more easily remembered by the operator if a permanent,
 conspicuous label is attached  to the degreaser summarizing them.  The
 difficulty of enforcement may  be minimized by educating the supervision  and the
 operator to the fact that proper operation and control equipment maintenance
 will usually provide a net profit from solvent savings.
                                      7-4

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7.1.4  Solvent Exemption Standards
     There is very little flexibility  in  converting  from non-exempt  to
exempt solvents.  A recent EPA notice  (42 FF, 35314)  has suggested that  the
only materials that should be allowed  exemptions are methane, ethane, 1,1,1-
trichloroethane, and trichlorotrifluoroethane.  This choice is  further
limited because of differences in solvency, flammability, cost, chemical
stability and boiling temperature.   In general, the exempt solvent approach
to regulating solvent metal cleaning is not recommended, because it does
not  achieve  positive emission reduction.  The rationale for this
fs discussed further in  Chapter 1.

7.2  AFFECTED FACILITIES - PRIORITIES
     Since there  is a wide diversity of  solvent degreasers, the definition
of facilities affected  by degreasing regulations must  be accurate.  Although
all  solvent  degreasers  may be subject  to potential  regulations, there are
an extremely large  number of degreasers; thus,  those with  greater emissions
should be given higher  priority  for enforcement.
 7.2.1   Definitions  of Affected Facilities
      The  following  defines the three  types  of solvent  degreasers  that can
 be  regulated.
      1.  Cold cleaner:  batch loaded,  non-boiling  solvent degreaser
      2.  Open top vapor degreaser:  batch loaded,  boiling solvent degreaser
      3.  Conveyorized degreaser: continuously loaded,  conveyorized  solvent
 degreaser,   either boiling or non-boiling.
 7.2.2  Priorities of Enforcement
       Individual degreasers that yield the greatest emission reduction  at
 reasonable  cost should  have the highest priority for enforcement.  Within
                                    7-5

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that grouping,  priority operations  are  vapor  degreasing  and waste  solvent
disposal  from all  degreasing  operations.   The lowest  priority  is assigned  to
cold cleaners,  especially maintenance type with  low volatility solvents, such
as those used with automotive repair.
     An emission reduction of 5  to  15 tons per year can  be achieved by
controlling a typical  open top vapor degreaser or conveyorized degreaser.
In comparison,  emissions from individual  cold cleaners usually cannot be
reduced by more than 0.1 tons per year  (see Appendix  B).  Even though
conveyorized degreaser emissions can be reduced  more  than open top vapor
degreasing emissions on the average, regulation  of conveyorized degreasers
before open top vapor degreasers is not recommended,  because  conveyorized
degreasers emit significantly less  solvent than  do open  top  vapor  degreasers
for an equivalent work load.   Thus, it  would  not be advantageous to encourage
degreaser operators to choose open  top  vapor  degreasers  in order to avoid
regulations on conveyorized degreasers.
     Waste solvent is a high priority area for control.   Controls  could be
directed towards solvent users, solvent producers, and/or solvent
disposal facilities.  It is the responsibility of the solvent user to properly
dispose of  his waste.   Facilities  which  accept  waste solvent  must use
disposal methods which minimize evaporation.   It is recommended that solvent
producers label new solvents to indicate  regulations on waste disposal.   For
example, a  label  could  read  that waste solvent should not be disposed of  so
that  it can  evaporate  into the  air  or  pollute the waters.  In addition to
regulating  degreasing waste  solvent disposal   a more comprehensive  enforcement
program which  would cover  disposal  of  all  waste  solvent and similar  volatile
organic materials  should be  considered.
                                     7-6

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     Although enforcement  of  regulations  on  cold cleaners is made difficult
by their large numbers,  it can be practical  when enforcement trips  are  com-
bined with other purposes, or if there are numerous  cold  cleaners and
other solvent degreasers at a particular plant.
                                      7-7

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APPENDIX A.  TEST RESULTS

-------
                        APPEND 13 A:  TEST RESULTS
                                 CONTENTS
                                                                         Page
A.I  Test results from Dow Report  	  A-1
A.2  EPA Cold Cleaner Test Report  	  A-3

-------
A.I  TEST RESULTS FROM THE DDK REPORT
     Under contract to the EPA the Dow Chemical Company tested eleven solvent
metal cleaners.  Detailed reports of each test are contained in the Appendices
to tfte document: "Study to Support New Source Performance Standards for Solvent
Metal Cleaning Operations," prepared under EPA contract no. 68-02-1329 by
K. S. Surprenant and D. ST. Rtc&ards and dated April 30, 1976.  A summary of
the  results  is given fn Table A-l.
                                       A-l

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                                                       TABLE A-l:  TEST  RESULTS FROM DOW REPORT
Dow Report*
Appendix* User
C-5 Pratt Whitney
C-2 Eaton

C-12 Dow Lab




C-3 Hamilton
Standard

C-10 Vic

C-7 Schlage Lock

C-ll W. Electric
Hawthorne

Oegreaser*
OTVD
OTVD

OTVD




OTVD
(#203)
OTVO
(O&R)
OTVD

CVD-
Monorai 1
CND
def luxer

UNSATISFACTORY CONTROL SYSTEMS
C-5 ' Pratt Whitney OTVD
C-8 Super Radiator
C-4 Hewlette
Packard

C-9 J. L.
Thompson


OTVD
CND
Monorai 1
Developer
CVD
Cross rod


Vapor Area
65" x 110"
49.6 ft2
.

24.2"x22"
3.7 ft2

24.2"x22"
3.7 ft2

15 ft2
11.1 ft2
12'x4.5'
54 ft2

41.3 ft2




56"x90"
35 ft?
6'x12;
72 ft2






Solvent
1,1,1
Tri.
1,1,1
1,1,1

1,1,1


Methylene
Chloride
Methylene
Chloride
Tri.

Perc.

Tri.


1,1,1
Perc.
1,1,1

Tri


TVD = Convi
(gal/unit) (Ib/ft2-hr) (gal/unit) (Ib/ft2-hr)
97.5 gal/wk
129 Ib/ton
111 Ib/ton





7.5 gal opday
6.43 gal /day
3.63 gal/opday
2.9 gal/day
108 gal/wk

19.5 gal/wday

0.063 gal/ft2 of
circuit board
23.8 gal/wday
58 gal/wk
49 gal /day
0.33 gal/board

1.4 gal/hr
*"
50.5 gal/wk
jvorized Vapor Degi
0.16
-
-
0.373
0.373
0.373
0.955
0.955
0.955
0.186
0.450
0.605

0.79

_


0.138
1.53





-easer, Cl
58.4 gal/wk
99 Ib/ton
80 Ib/ton





4.53 gal/opday
3.67 gal/day
2.60 gal/opday
1.73 gal /day
38 gal/wk

7.5 gal/wday

0.025 gal /ft2

10.4 gal/wday
49 gal/wk
37 gal/day
0.26 gal/board

1.06 gal/hr

49.5 gal/wk
ND = Conveyor! zed
0.10
-
-
0.373
0.273
0.167
.
0.051
0.054
0.112
0.322
0.213

0.304

-


0.117
1.14





Non-boiling
Efficiency
40%
23%
28%
0
27%
55%
-
46%
43%
>40%
>43%
28%
40%
65%

62%

60%


16%
-8%
21%

25%

50%
Degreaser,
Control System
Cover-pneumatically
powered
Cover (manual)

FR = 0.5
- 0.75
• 1.0
FR • 0.5
0.75
1.0
Cold Trap
FR = 0.83 (covered
during disuse)
Cold Trap
FR = 0.75
(never covered)
Carbon adsorption

Chiller

Carbon adsorption


Cold Trap
Carbon Adsorption
Carbon Adsorption

Carbon Adsorption

Carbon Adsorption
Opday - Day degreaser
Comments
Uncovered for 24 hrs/day and
7 day/wk
No much Information on the test.

Idle (no work loads), moderate draft
_
Idle, quiet air


Work load when CT on was 50% more than when
CT off -«> 40%.










Inaccurate results. The O&R deg 1s expected to
have a higher n, due to being uncovered. O&R had
only ^-*rlf loa<|s P6*1 operating day whereas #203 had
Ventilation rate of 103 cfm/ft2. Accuracy of record-keeping
Is report** % Dow to be poor. Thus, accuracy of results
would be poor.
Range of n 1s 45 to 65%.




FR = 59%, Cold Trap design tested here was reported
obsolete model. Covered during disuse.






as an
Defective adsorption system - breakthrough; Insufficient
FR 0.04 jjFR<_ O.J. Only 37 cfm/ft^
Low control efficiency of the adsorption system is
to be because of poor ventilation design.

Material balance results

Resulcs from purchase records
1s
thought





in operaT.iun, wuay - wuiMiiy  uaj ,  ^>    MUI-* ><«*v» •'>   • ••	^  •-•
1,1,1 = methyl chloroform,  Tri.  =  trichloroethylene, Perc. •= perchloroethylene.
'The appendix of the''Dow  Report  describes each test in detail.

-------
A.2  EPA COLD CLEANER TEST REPORT

-------
                TEST REPORT


EVAPORATIVE EMISSIONS STUDY ON COLD CLEANERS
                      By

              Walter Pelletier
              Peter R. Westlin
    U.S.  ENVIRONMENTAL PROTECTION AGENCY
 Office of Air Quality Planning  and Standards
 Research Triangle Park,  North Carolina 27711
                  May, 1977

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                                    SUMMARY
     A preliminary study of cold cleaner solvent emissions was  undertaken,
the purposes of which were to quantify hydrocarbon solvent evaporation  losses
from typical air-agitated, pump-agitated, and unagitated cold cleaners; and
to establish relationships between evaporation rates and several  controlled
test parameters.  These parameters included solvent volatility, room draft
velocity, freeboard  ratio, and cold cleaner operation.
     Results of  these tests  indicate that highly volatile solvents, such as
perch!oroethylene, used  in different types of cold  cleaners with different
types  of  solvent agitation produce  comparable evaporation rates.  Solvents
emissions from air-agitated, pump-agitated,  and unagitated units showed similar
 test results with perch!oroethylene as the solvent.  With less volatile
 solvents, such as Mineral Spirits,  agitated  cold cleaners showed significantly
 greater solvent emissions than did  the unagitated.   In  addition, these test
 results demonstrate a tendency for  solvent emissions to increase as the room
 draft velocity  is increased.  Closing the cover on a cold  cleaner  drastically
 reduces solvent emissions as is also shown in these tests.
      An  increase in solvent emissions with a decrease in freeboard ratio  in
 unagitated  units is indicated by these test results.  Also indicated is an effect
 on  solvent  emissions caused by  the shape of the sol vent-to-air interface area
 of  unagitated tanks.   For these tests, a square sol vent-to-air interface surface
 resulted in greater solvent emissions  than  did a rectangular one.  This result
 may be affected by  the orientation of the tank to  the  room draft air movement.
       The effect of  solvent  volatility on evaporation rates  is shown as increased
  volatility produces increased solvent emissions.   The  largest difference  between
  solvent emission rates is shown between tests  with the highly volatile,
  relatively pure perch!oroethylene  and the mineral  spirits mixtures.

-------
                        TABLE OF CONTENTS
                                                       Page No.



  I.  INTRODUCTION	   -,
 II.  EQUIPMENT AND SOLVENTS
III.  TEST PROCEDURES	   2







 IV.  DISCUSSION OF RESULTS	   5



           Appendix A:   Test Data	15



           Appendix B:   Solvent Analyses  	  21

-------
                               I.   INTRODUCTION
     The Emission  Measurement Branch of the Emission  Standards  and
Engineering Division undertook a laboratory study of  cold cleaners  used  for
parts degreasing.   The purpose of the study was  twofold:  first, to  quantify
hydrocarbon solvent evaporation losses from typical air-agitated, pump-agitated,
and unagitated cold cleaners; and second, to establish relationships between
evaporation rate and several test parameters including solvent volatility,
room draft velocity, and free-board ratio.
     In this preliminary study, a minimum number of data have been  collected.
In most cases, each data value represents only one test run, the curves  are
plotted with only two or three points, and comparisons are made based on only
two or three test runs.  The results included in this report should be regarded
as preliminary and, at best, only indications of trends that can occur with cold
cleaner solvent emissions.
     The tests were conducted at the IRL laboratory under controlled conditions.
Four different cold cleaner models were used for this study: an air-agitated
Kleer-Flo model 90 unit, a pump-agitated Gray Mills model 500 cleaner, a Kleer-
Flo model A-15 unagitated unit, and a Gray Mills model SL-32 unagitated  cleaner.
The four different solvents used for these tests were perchloroethylene, 102
mineral spirits, 112 mineral spirits, and 140 mineral spirits.
     The results are expressed in mi Hi liters of solvent lost per hour per
                                       2
square meter of surface area (ml/hr . m ) and in grams of solvent lost per  hour
                                          2
per square meter of surface area (g/hr . m ).  These  data are used  to develop
curves displaying the relationships between evaporation rate and the test
parameters.
                            II.  EQUIPMENT AND SOLVENTS
     A schematic of the Kleer-Flo model 90, an air-agitated cold cleaner, is

-------
                                                   2
          shown in Figure 1.  The air for agitation was supplied by an industrial
          compressor, and the rate of air injection was set at a relatively constant
          4 to 5 liters per minute with the use of a calibrated orifice meter.  Although
          not used in any calculations, the air injection temperature was monitored with
          a dial thermometer.
               The pump-agitated cold cleaner used in these tests was the Gray Mills
          model 500 unit.  This unit was connected to a timer-switch set to run the pump
          agitator for 20 minutes out of every 65 minutes in a repeating cycle for all
          test runs.  This was done to avoid over-heating the solvents and to more
          realistically represent the operation of the cleaner.
               Tests of unagitated cold cleaners were  performed  using two different sized
          units.  One was a  Kleer-Flo model A-15 shown in Figure 2.  The other cleaner
          was  a Gray Mills model  SL-32.  Calibrated  thermocouples were used to measure
          solvent temperature and ambient  temperature  for these  test runs as  well  as  for
          the  other  test  runs.
                                          III.   TEST PROCEDURES
                The measurements  made for each  test included solvent volume,  room  and
           solvent temperatures,  room draft velocity, and solvent density.   Temperatures
           were measured with chrome!-alumel  thermocouples  calibrated at the water-ice
           point and  at water boiling temperature corrected for barometric pressure.   Re-
           corders were used to monitor these temperatures  over an extended period of
           time.  The temperatures reported in this report represent runs averages that
           have ranges of about +. 5°K.  Accuracy of the measured values is estimated at
           + 1°K.
                Room draft velocity was measured with an A!nor thermo-anemometer held
           30 cm  above the top of the tank.  The measurements are estimated to have a
           +_ 10 percent accuracy  for draft velocities above 30 m/min while below this
10

-------
                                                                        Figure  l:  Schematic  Diagram'of
                                                                             Kleer-Flo Model  #90
                                                                                       Cold Cleaner
                                                                                  COVER
                                                                                    09-A
                                                                                   SUPPORT ARM ASS'M
                                                                                         IO
                                                                                   SPRING CLOSURE
                                                                                         10-2
                                                                                   FUSIBLE  LINK
                                                                                        10-1.
                                                                                   LOWER HOSE
                                                                                       12
                                                                                — BARRIER FILTER
                                                                                        13
                                                                                   •FILTER HOUSING
                                                                                         14-1 •
                                                                                   FILTER CARTRIDGE
                                                                                         14-5
                                                                                   -MOTORS. PUMP ASS'M
                                                                                          15
KLEER-F 0  SUPER  CLEANMASTER
            MODEL  90
                                                                                                        NOT 5HOWJL
                                                                                                                      07
CASTERS  02-2
DRYING  SHELF
BASKET   08
COVER KNOB  09-2
BRUSH  83-1
BRUSH HOLDER  09-1
     _
   RIGHT  HAND
   LEFT HAND  Oo
 AIR GUN  03-14
 AIR HOSE  OJ-ll
 AIR  VALVE   O3-9
 MOTOR LOUVRE  04
 SWITCH  04-2
 INDICATOR  LIGHT  04-
 RESERVIOR  COVER  05-

-------
                                                   (COVEft ANO 6ASh£T REMOVED)
                                                   Figure  2:   Schematic Diagram   .
                                                           of  Kleer Flo Model # A-15
                                                                  Cpld Cleaner  •
                                               •COVER
                                               (l 509)
                                          .-BASKET
                                           (1506)
12
      '' MAM I 0«-D

-------
                                         5
level,  the accuracy falls to about +_ 20 percent.
     Solvent density was determined gravimetrically before and after each
test run.  Solvent volumes were measured with calibrated containers.  Accuracy
of these measurements is estimated to be about + 2 percent.  Samples of solvents
were collected for analysis of distillation characteristics and volatility.
These data are shown in Appendix B.
     Prior to initiation of the test, the cold cleaner units were partially
filled with solvent and operated, if applicable, for a short period.  This
conditioning step filled any reservoirs with solvent.  After the cleaner was
drained, a measured amount of solvent was placed in the cleaner and the test
conditions were set as desired.  Draft velocity was maintained with a laboratory-
hood exhaust fan and small, caged, portable fans.  At the end of the test period,
the solvent was drained  from the cold cleaner in the same manner as was completed
earlier.  The volumes were measured with  calibrated containers and the volumes
were recorded.  Test conditions such as solvent temperature, ambient temperature
and humidity, and other  test parameters were recorded.
                            IV.  DISCUSSION OF RESULTS
     Tables 1 and 2 show the results of tests with the air-agitated and pump-
agitated cold cleaners,  respectively.  The test data for the two unagitated units
are shown in Tables 3 and 4.  Figure 3 shows a plot of the relationship between
evaporation rate of perch!oroethylene and room draft velocity for these cleaners.
The scatter in the results  shown on this  figure indicates  that the  type of cold
cleaner  and the agitation method have  little effect on the evaporation rate of
a highly volatile solvent such  as  perch!oroethylene.  One  result that is evident
is that  the evaporation  rate of solvent increases  with an  increase  in room draft
velocity for  all  types  of cleaners.  The  data  show that  for  the air-agitated  unit,

-------
TABLE 1.  EVAPORATION RATE TEST RESULTS FOR THE
       AIR-AGITATED COLD CLEANING UNIT
Solvent
Perchloroethylene
Perchloroethylene
Perchloroethylene
112 Mineral
Spirits
140 Mineral
Spirits
140 Mineral
Spi ri ts
Cover
Position
Open
Open
Closed
Open
Open
Open
Room
Draft
(m/min)
27
85
83
4
3
22
Evaporation
Rate
(ml/hr . m2)
616
1758
143
83
34
75
Evaporation
Rate
(g/hr . m2)
992
2848
231
65
26
57

-------
      TABLE 2.   EVAPORATION RATE TEST RESULTS FOR THE
              PUMP-AGITATED COLD CLEANING UNIT
Room
Draft
(m/min)
64
28
97
Evaporation
Rate
(ml/hr . m2)
1167
464
423
Evaporation
Rate
(a/hr . m2)
1891
751
677
Solvent



Perchloroethylene



Perchloroethylene
 Perchloroethylene     No
                   Agitation
 102 Mineral                                                         186
   Spirits                      59                *w
 140 Mineral                                       ,.
   Spirits                      3                 64

-------
TABLE 3.  EVAPORATION RATE TEST RESULTS FOR AN

        UNAGITATED COLD CLEANING UNIT



           GRAY MILLS MODEL SL-32

  (Dimensions:  81 cm x 41 cm x 25 cm Deep)


   ,_   ,     , n ..      Freeboard Height\
   (Freeboard Ratio  =	a—)
Freeboard
Solvent Ratio
Perchl oroethylene
Perchl oroethylene
Perchl oroethylene
Perchl oroethylene
102 Mineral
Spi ri ts
102 Mineral
Spirits
102 Mineral
Spirits
HO Mineral
Spirits
140 Mineral
Spirits
0.27
0.50
0.29
0.50
0.50
0.29
0.50
0.29
0.50
Room
Draft
{m/mi n )
57
52
3
3
52
3
3
3
3
Evaporation
Rate
(ml/hr . m2)
1156
824
56
8
142
9
8
n
4
Evaporation
Rate
(q/hr . m2)
1873
1311
89
12
109
7
6
8
3

-------
TABLE 4.  EVAPORATION RATE TEST RESULTS FOR AN
            UNAGITATED COLD CLEANER

             KLEER-FLO MODEL A-15
  (Dimensions:  33 cm x 33 cm x 32 cm Deep)
                        Freeboard Height^
VrreeDoara Kdtiu
Freeboard
Solvent Ratio
Perchl oroethyl ene
Perchl oroethyl ene
Perchl oroethyl ene
Perchl oroethyl ene
Perchl oroethyl ene
102 Mineral
Spirits
102 Mineral
Spirits
102 Mineral
Spirits
102 Mineral
Spirits
140 Mineral
Spirits
140 Mineral
Spirits
140 Mineral
Spirits
0.20
0.42
0.20
0.42
0.74
0.42
0.20
0.42
0.74
0.20
0.42
0.74
33
Room
Draft
(m/min)
58
53
3
3
3
53
3
3
3
3
3
3
/
Evaporation
Rate
(ml/hr . m2)
1508
1210
88
20
27
159
26
27
24
9
11
11
Evaporation
Rate
(q/hr . m2)
2442
1937
141
31
43
124
20
20
18
7
9
8

-------
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-------
                                       11
                                                                            2
the evaporation rate of perchloroethylene increases  from about 1000 g/hr .  m
at a room draft velocity of 27 m/min to over 2800 g/hr . m2 at 85 m/min.  Tests
with the other models showed similar results.
     A third test run was made with the perchloroethylene in the air-agitated
cold cleaner with the lid closed.  At a draft velocity of about 85 m/min, the
                                                           2
evaporation rate with the cover open was over 2800 g/hr  . m , while with the
                                                                    2
cover closed,  the evaporation rate was reduced to about  230 g/hr  . m .  This
represents better than  a 90 percent reduction in emissions.
     Results of  tests with less volatile minerals spirits  showed  somewhat
different  relationships.  At  room draft  velocities below 5 m/min,  the agitated
cold cleaners  showed significantly  greater  evaporation  rates  of mineral  spirits
 than did the  unagitated models.  For  example, under  similar  test  conditions and
 room draft velocities under  5 m/min,  the emissions  from the  air-agitated cold
 cleaner were about 25 g/hr .  m2  of 140 mineral  spirits, the  pump-agitated unit
 emissions were about 50 g/hr . m2,  while the unagitated unit emissions  were less
 than  10 g/hr  . m2.  Data from tests at higher draft velocities are limited, but
 a similar result can be shown for  the evaporation rates of 102 mineral  spirits
 at 50 to 60 m/min draft velocity from the pump-agitated unit and from the two
 unagitated models.
      For these  tests freeboard ratio is defined as the  height from the surface
 of the  solvent  to  the  top of the tank (freeboard height)  divided by the length
 of the  shorter  side of the tank.   Figure 4  shows the relationship of the
 evaporation rate of perchloroethylene versus freeboard  ratio.  The figure
 demonstrates  the  tendency for solvent emissions to  decrease  as the freeboard
  ratio  is  increased.

-------

-------
                                       13
     Figure  5 displays  the  relationship between evaporation rate of various
grades of Mineral  Spirits  Events  and freeboard ratio.  Solent losses for
these tests  were extre*ly small  and the  Inherent  Imprecision In measuring
these small  differences probably account  for the lack of clear  trends on this
figure   One notable result demonstrated  Is that the KUer-Flo  A-15  cold
cleaner  showed greater evaporation losses under the same conditions  than did
the  Gray Mills cold cleaner.  This difference may be due to the difference
 in the shape of  the two units.   The  Kleer-Flo model has a square solvent-to-
 air interface  area, while  the Gray Mills unit has a rectangular C- 2:1  length
 to width ratio)  interface area.   These data are normalized as  to the solvent
 area, and the conditions  under which these data were conducted were lto.tic.1.
 so any  difference between test results from the two tanks  may  be because  of
 the  shape difference.  In addition, the  Gray Mills tank was  oriented the  same
 way  for all tests; that 1s,  the room draft direction was  parallel with the
  short sides of  the tank.  Turning  the tank  so that the room draft direction i.
  parallel with   the long sides of  the tank  would Hkely produce different  results.
       The effect of solvent volatility,  In  terms of solvent Initial  boiling
  temperature,  an evaporation rate Is demonstrated  In  Figure 7.  For this figure,
  an  increase In Initial  boiling temperature corresponds to a decrease  In solvent
  volatility.  The slopes of the three curves on Figure 7  Indicate that evaporation
   rates  decrease with decreasing solvent volatility.  The  Kleer-Ro  A-15 mode!  cold
   cleaner was used for these  tests.  It Is  not apparent that the square surface
   shape of  this  unit  had any  effect  on these results.

-------
o
                                                     "jCr-'  ra  ft.;:
                                                            -    '-:

-------
Ott,
  I
                                          01*
                                                              OO

-------
APPENDIX A
TEST DATA

-------
PO
en
                                                     TABLE A.  EVAPORATION TEST RESULTS FOR THE KLEER-FLO MODEL 90
                                                                       AIR-AGITATED COLD CLEANER


                                           (Surface Area of Agitated Section = 0.398 m2, Total Solvent Surface Area = 0.974 m  )
Run
1-A
Open
2-A
Open
3-A
Closed
4-A
Open
5-A
Open
6-A
Open
Solvent
Perch! oroethylene
-
Perchloroethylene

Perch! oroethylene

!12 Mineral
Spirits
140 Mineral
Spirits
140 Mineral
Spirits
Ave.
Room
Temp.
293

290

293

293

293

295

Ave.
Solvent
Temp.
291

289

292

389

293

295

Ave.
Injected
Air
Temp.
( K)
291

290

292

288

291

293

Ave.
Injected
Air
Moisture
w
1.6

.0.8

0.4

1.5

1.7

1.5

Ave.
Injected
Air
Rate
(1/min)
4.9

4.0

4.2

4.4

4.8

5.0

Ave.
Room
Draft
(m/min)
27

85

83

4

3

22

Solvent
Density
(g/ral )
1.61

1.62

1.62

0.78

0.77

0.77

Test
Run
Time
(hrs:min)
19:08

16:40

16:16

47:19

89:53

74:25

Volume
Loss
(1)
8.34

28.54

2.26

3.81

3.00

5.41

Evaporation
Rate y
(ml/hr . i/)
616

1758

143

83

34

75

Evaporation
Rate ?
(g/hr . nT)
992

2848

231

65

26

57


-------
                     TABLE  B.   EVAPORATION TEST RESULTS FOR THE GRAY MILLS MODEL 500
                                       PUMP-AGITATED COLD CLEANER
Run
Solvent
                                        (Surface Area  =  0.415 m )

                              Ave. Room  Ave. Solvent   Ave. Room
                                Temp.         Temp.        Draft
                       Solvent  Test  Run
                       Density    Time
                       (g/ml)   (hrrmin)
Volume  Evaporation   Evaporation
 Loss      Rate   ?      Rate  „
 (1)    (ml/hr .  nT)  (g/hr . nT)
1-B
2-B
3-B
lo Agi
4-B
Perch! oroethylene
Perchloroethylene
Perghl oroethylene
tation
102 mineral
Spirits
292
293
299
288
293
• 295
298
292
64
28
27
59
1
1
1
0
.62
.62
.60
.76
21:18
43:08
93:35
95:47
10.
8.
16.
9.
32
34
4
7
1167
464
423
244
1891
751
677
186
5-B   140 Mineral
        Spirits
                   292
295
                                                        0.77     90:27
                                            2.4
            64
49

-------
TABLE C
EVAPORATION TEST RESULTS FOR THE GRAY MILLS MODEL SL-32

          UNAGITATED COLD CLEANER
                                           2
                  (Surface Area  =  0.332 m )
Ave. Room
Temp.
Solvent (°K)
Perchloroethylene
Perchloroethylene
Perchloroethylene
Perchloroethylene
102 Mineral
Spirits
102 Mineral
Spi ri ts
102 Mineral
Spirits
140 Mineral
Spirits
140 Mineral
Spirits
290
292
298
292
290

295

297

296

299

Ave.
Solvent
Temp.
292
294
298
292
293

293

296

294

297

Ave.
Room
Draft
(m/min)
57
52
3
3
52

3

3

3

3

Freeboard
Ratio
0.27
0.50
0.29
0.50
0.50

0.29

0.50

0.29

0.50

Solvent
Density
(g/ml)
1.62
1.59
1.60
1.61
0.77

0.76

0.76

0.77

0.76

Test Run
Time
(hr:min)
16:09
16:20
137:15
116.27
98:59

137:50

141:25

115:20

164:30

Volume
Loss
(1)
6.2
4.5
2.5
0.3
4.7

0.4

0.4

0.4

0.2

Evaporation
Rate 2
(ml/hr . m )
..,-.,. i — .
1156
824
56
8
142

9

8

11

4

Evaporation
Rate o
(g/hr . nr)
— —..... ., - . 	 — •
1873
1311
89
12
109

7

6

8

3


-------
                            TABLE D.   EVAPORATION TEST RESULTS FOR THE KLEER-FLO MODEL  A-15
                                                UMAGITATED COLD CLEANER

                                             (Surface Area  =   0.109 m2)
Run
1-D
2-D
3-D
4-D
5-D
6-D
7-D
8-D
9-D
10-D
11-D
12-D
Solvent
Perchloroethylene
Perchloroethylene
Perchl oroethyl ene
Perchloroethylene
Perchloroethylene
102 Mineral
Spi ri ts
102 Mineral
Spirits
102 Mineral
Spirits
102 Mineral
Spirits
140 Mineral
Spirits
140 Mineral
Spirits
140 Mineral
Ave.
Room
Temp.
(°K)
290
292
298
292
300
290
295
297
299
295
299
295
Ave.
Solvent
Temp.
(°K)
292
294
299
292
299
293
293
296
297
295
298
295
Ave.
Room
Draft
(m/min)
58
53
3
3
3
53
3
3
3
3
3
3
Freeboard
Ratio
0.20
0.42
0,20
0.42
0.74
0.42
0.20
0.42
0.74
0.20
0.42
0,74
Solvent
Dens i ty
(g/ml)
1.62
1,60
1,60
1.61
1,60
0,78
0.76
0.76
0.77
0.77
Q.76
0.77
Test Run
Time
(hr:min)
16:09
16:20
92:40
117:17
71:25
98:59
92:40
140:55
93:10
114:40
164:15
75:30
Volume
Loss
(1)
2.7
2,2
0,9
0,3
0.2
1,7
0,3
0.4
0.2
0.1
0.2
0.1
Evaporation
Rate 9
(ml/hr . ITI )
1508
1210
88
20
27
159
26
27
24
9
11
11
Evaporation
Rate 9
(g/hr . r/)
2442
1937
141
31
43
124
20
20
18
7
9
8
Spirits

-------
   APPENDIX B



SOLVENT ANALYSES

-------
  DATE:

,UBJECT:


  FROM:


    TO:
        UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
May 4, 1977
Analysis of Mineral Spirits and Perchlorethylene
                            Chemistry  Section,  ACB  (MD-78)
 R. Shigehara,  OAQPS/EMB (MD-13)
 W. Pellitier,  OAQPS/EMB (MD-13)
                  Seventeen samples were  submitted to this  laboratory  on  a
             Sample  Request and  Report Form dated April  21, 1977.   Reid Vapor
             Pressure and Distillation analysis was  requested.   Distillations
             were run on all  but one  sample where a  specific request was  made
              that it not be run.  Reid Vapor Pressure was requested and attempted
              on all  samples but only three samples had enough pressure for positive
              measure.  This analysis was conducted using the ASTM Method D-323.
  EPA Form 1320-6 IRc«. 3-76>
o .

-------
 REPORT OF ANALYSIS
  TRACE ELEMENTS
 ppm • (or solid sornples
ug/ml - for liquid samples
                                                                                                Mc-V (xi (or specific c':',ns
                                                                                                   (i| m block to lei! o! Ifleil. No
                                                                                                      oil onol)Sis on '.fxji line
                 m LJ m LznnnnrEjij LJ LJ L
                                             JIITTIJT:JTJIIJIITT:JTITTJ i   ih LJ CTEJT


                                                                                  ; ZTT: ire JT: TT; n
                                       c iru im JTTJT: un ire im im irt 3T±n: jn ire ITT- D
                                                                                      im 3ijTr uxc
           I-HAA, 2-SSMS, 3-OES, 4-AA, 5 AGV, 6-XRF, ond 7-otliei
; "-' fi^'^'S • U'e Totiie B lo fill ordysis requsiletl [o5o/e etch column)
                                                                                                     MorX (x) loi spccilic analysis 'e^s'.'.

-------

TRACE EUVEVS V;-* ~*i'
^ 3.BP
J 32-1
_J 7^2
_l 5T3/7
j-r-,f *J *j ,* -it
\ *2. t "s
J $.*/£
J 5^J-
—1 3?-6
u-T 23o
u


lo %
J ?3c,
J ^33
J $1/0
-JJ55
-I.3/Z-?
-1 3>/S
— 1 3?-£
J 3}£
J ^-z^/fr
J


So'h
J 3**-
LJ 323
J $43
, 	 1 %£/
	 1 •?,£ /
— 1 £•/£
J 333
-J 333
-Jjy/
u


*? o '/o
— J 313
J if£
U ^f3
J sfi/
-J 31}
-J MS
LJ^/7
— ' 3/7
LJ 370
J


//*
— 1 f//s
J 1/J.f
J y/2%
J t/zg
J ¥o1
_T zfb
J _j^f
-J 39&

J



J
J
J
J
J
U
lJ
J
J
J


RvP*
J
J
J
J
J
J 0.0
J
J
J

e, <(L
V- *-v3

J
J
J
g
J
J
J
J

J
J



U
ul
J
J
J
'•-
J
J


e
c
e
c
c
c
o
o
o
e t
e P
0 I
0 |
e '
e
Q
Q
C
t-
C j
c
of

Co.rients.

-------
                                                                                   S^-'^.*-«.;3»^*^.^a5»AML^'-J^^-';*^                            V*^-..jh-.4"
o  t>  ©i©  o  o  © o' e' ojo o  o  ®.•Je
             iil^I
              o © o o
                                                             o
                                                                o
                                                   oe
oioio
                                                                                         © ©
                                                             ©
©  O !© JO
                                 e
oe oO®  o
©  © ©
                                                                                                                                         _L
                                                                                 _L
 SAMPLING DATE
                                                         SOURCE SAMPLE REQUEST & REPORT
                                                         (MUST BE FILLED OUT FOR EACH TEST RUN)
               YR
               MO
DAY
FIRST IDENT.
NO. USED
                                                     - ooa-
LAST IDENT.
NO. USED
                                                                                                                           TEST NO
                                                                                                                               RUN NO
        INDUSTRY   TeLwtrf'^ov*	V\.
                               (USE TABLE A)
                                                I^VQ'
        COMPANY.

        ADDRESS .

        SAMPLING.
        METHOD
                                   V
                                             UNIT PROCESS OPERATION.

                                              AIR POLLUTION CONTROL.

                                                         FUEL USED.
                                                                                                                                                          e
                                                                       D INLET  D OUTLET
                                                                    CAS VOLUME SAMPLED	
                                                                     (METER VOL IN  FT3)
  IDEM NO
       JaSS
                           DESCRIPTION OF
                         SAMPLE OR SAMPLE
                             FRACTION
                                    >o
                   ./f^//)
                                                        To
                                                                       SAMPLE
                                                                   WT          VOL
                                                                 (SOLID)
                                                                   MG
                                                       (LIQUID)
                                                         ML
                                                                             Soo
                                                                             5oO
                                                                  ANALYSIS REQUESTED - GENERAL COMMENTS
                                                             (APPROX CONCENTRATIONS - POSSIBLE INTERFERENCES
                                                               ETC)  (INDICATE SPECIFIC ANALYSIS ON BACKSIDE)
                                                                                                                                   c-\i t-,vx  /\
                                                                                                                                                   3
                                                                                                                       n
                                                                           -1°
                                                                           L*i
                                                                           ;o [
                                                                           ;?!
                      ^AL
                                                                                                                                                       o
SAMPLING
CONTRACTOR	
                                                      .PROJECT
                                                                                     \ t^Sis^CuL
                                                                                                                  REQUEST
                                                                                                                          RY
                            (IF APPLICABLE)
D-ATE P . ".EQUEST	^ -  SV -^\"3	
                                              _DATE ANALYSIS REQUESTED.
                                                                                   DATE OF REQUEST	
                                                                                                                            (iQ aE FiLLtD IN br :>;>rA6)

-------
Samples of Mineral Spirits and Perchloroethylene From EMB.
                                  Distillation

Sample No.
S-77-002-602
-603
-604
-605
-606
-607
-608
-609
-610
S-77-002-639
S-77-002-656
-657
-658
-659
-660
-661
-662
- •"
Ton
IBP

.
326 330
332 333
339 340
332 333
327 328
245 245
Distillation Not
322 325
325 325
330 330
369 372
317 327
368 371
364 371
369 372
246 244
246 245
..
50%

352
353
353
351
351
245
Requested
333
333
342
378
342
379
379
380
245
! 245
90%

383
386
383
384
382
245
359
357
370
393
371
395
395
394
246
246
EP RVI

415
428
423
423
409
286
388
392
409
417
411
423
423
420
286
290
                                                              0.0
                                                              0.5
                                                              0.9
                                                              0.8

-------
' REPORT OF ANALYSIS
TRACE ELEMENTS
5 ppm - for solid samples
Q eg/ml - for liquid samples
O 	
i
O
o
o
o
o
©
0
©
©
o
©
o
o
0
•0
e
o
o
o
o
Ident No.










Ar










olysis M
Hq
J L
J L
J L
J L
J L
j d
J L
J L
J L
1 1
ethod:
Be
J L
J L
J L
J L
J LJ
J L
J L
J L
J L
1
l-NAA,
Cd
J L
J L
J L
J L
J L
J L
J L
J L
J L
J L
As
J L
J L
J L
J L,
J U
J L,
r1 L
J L
J L
J L
V
J L
J L
J L
J U
J L
J L
TT_
J L
J L
J L
Mn
TE
J L
J L
J L
J L
J L
ITC
r1 L
TT:
J L
Ni
TT:
TT
J L
r1 L
J L
TT
im
J L
TT:
J L
Sb
TT:
TT:
J L
TT:
J L
TT
TT:
TE
TTJ
J U
Cr
TT:
J L
J L
TT_
J L
ZTL
TTJ
TT:
T"L
J L
Zn
TT:
J L
J L
J L
J L
J L,
TC.
TT_
J L
J L
Cu
J L
r1 L
r1 L
J L
TT:
J L
J L
J L
J L
J L
Hb
J L
J L
J L
J L
_F L
J L
J L
U L
J L
J L
lie
J L
J L
J L
pl L
J L
J L
J L
J L
J L
J L
B
J L
J L
J L,
J L
J L
J L
J L
J L
J L
J L
F
J L
J L
J L
J L
J L
J L
J L
J L
J L
J L
LI
J L
J L
r1 L
r1 L
J L
J L
J L
J L
J L
J L
Ag
J L
J L
J L
J L
J L
l_iT_
J L
J L
J L
J L"
Sn
J L
J L
r1 L
J L
J L
TH
J L
J L
J L
TT:
Fe
J L
J L
J L
J L
J L
TI
J L
TT:
L
J L.
Work (n) for specific analysis
Mark (n) in block to left of Ident. No w
requesting all analysis on thot line
Sr
J L
L
J L
L
J L
L
J L
J l_
L_

No
J L
J L
J L
L
J L
TJ
L
J L
T L
T_
K
J L
J L
L
L
L
L
\—
TL
J L
L
Co
L
J L
L
L
L

L_

_1 L
L
Si
J L
J L
L
L
L

L

_l L
L
Mg
J L
J L
J L.
L
L
I 	 f-T 	
J L
L


L
Bo
— i — i —
J L
— i —
L.
J L
— i —
L
3
i_
~~i —
L
— i —
i_
D— T—
L
— i —
1_
— i — i —
_l L
— i — i —
_J L
— i —
L
— i — i —
i— ' "—
— i —
L
— i — '
1 —
D— i —
L_
D— i —
1 	
— I — i —
_! L
— i —
L
— i — i —
_J L_
— i —
L_
a— r~
1 	
— r
L
— I —
L_
i i
_J l_
D— r~
'
"TT — 1 1
— ! — 1 — 1 F
m— r—
1 —
D~l — 1 I I —
1 j 1 L_
P~\ — n —
LJ L
D_ 	 p-^
D"~i — \~~r

I!,.
— M ' — r~" "~
2-SSMS 3-OES 4-AA, 5-ASV, 6-XRF, end 7-other Comments.

nthpr Analysis - Use Table B to fill analysis requested (obove each column)
Ident No.










A
/ x/
/ ^7
*
///
(to





lalvst
Method
Comments:
i^Of J°




J


J










A.
/ 'D ~ f^
7teiz&P~^

" i/?/


3 (,$
3/7
J Itf

3, i/
_J 3tf












/o "/•>


$12
3 3-7
\ y^/

57/
-J ?7£












>& '/o
37?
3
?7f
37?
•?f(?



•



9o %





333
31/
qft/
?^/
3?tf
_









X/'

f//7
3 t///

	 1 (j i ^
— i i/Zv
J

J
J
J



11
U

_l
D
J
-1
-J
-J
J


Maft M for specific
— i 	 • —
m
i]
	 , —

j
n
	

-i
j
J


— i— 	 	 — —
J
	 	 	
U
	 1 	
U
— I 	 '-'-• •"-• --^
J
— I 	
_l
— 	
J
— J 	
_J
— 1 	 '
J
	 r 	
J


onolysis '
— i 	
_J

— '
J
J
-[
-J
	

-1





-------
] .
i
\
i
4
1
1
1 !
t !
i
3
i
2
t
i i
t
,
t
ojr
°!s
o -
o *
01"
pi-
f>!:'
t
c,°
o'-
0 :-
O =
O *
1
1 M
o -
© -
o •
-r
o'-
o -
© -
o *
OJ
'
SAMPLING DATE
INDUS
COMP
ADDR
SAMP
METH
IDENT NO

r^~~ 	
-


1 	

\n A ~>"i 1
(' l\ A SQJ i
JYR MO DAY 1
(USE
ANY, 	
h55> - 	
LING. 	
00
suURCE SAMPLE REQUEST & REPORT
(MUST BE FILLED OUT FOR EACH TEST SUN)
TEST NO 	
'FIRST IDENT. LAST IDENT. -
NO USED S-T-l.OOa.^X HO. USED 5 ~ ^^ - OO^ - <-^ RUN NO 	

TABLE A)



DESCRIPTION OF
SAMPLE OR SAMPLE
FRACTION
,-> VVN o, »v s K r • a

N




1 COMMENTS: 	 —
j 1 	 	 	 ,. .
SAMPLING
UNIT PROCESS QPERATIOf
A!R POLLUTION CONTRO
FUEL USE
D INLET D OU
GAS VOLUME SAMPLE
(METER VOL IN FT3
SAMPLE
WT VOL
(SOLID) (LIQUID)
MG ML
49,0
S>oo





i 	 __ 	 • —

n 	 . 	 — 	
TLET
n..... 	 — 	

ANALYSIS REQUESTED • GENERAL COWENTS
(APPROX CONCENTRATIONS - POSSIBLE INTERFERENCES
ETC) (INDICATE SPECIFIC ANALYSIS ON BACKSIDE)
\l,\A. Ve,c,4.i_J?VT ",'.— <• ' T^XAVaW 	 V
\t
	 	 	 ^- 	 — 	 — 	
	 — 	 	 	 — 	
_ 	 — 	 — -
	 — — 	 — 	 	 .

REQUEST
Bnnirr.Tnrnr.rn t.NAV.,o> ^A^ .V.ns^ „ REVIEWED BY 	
CONTRACTOR 	 	 ___...«,.,.-,,. .....
(IF APPLICABLE)
fL r^nnccT niiTe «u»i vci« pcnn«TFn 	 _____ DATE OF REQUEST 	 _______ _ /ti n
DA!t 01- RtQUEST_ 	 _ 	
i




-------

* — .*-^,<--_»2f.-tt- jift-f---M--'- A>-;t_UiV-^.T.r"J-j""'A-r'-'^ --"-**-**S*-*-
t> o e ''e^©'© i© i©1© 'o oiolo
1
SAMPLING DATE
INDUS
COMF
ADDR
SAM?
METh
1DHNT NO

Co 3

Gc-s
(_ry


~~ Cen
,
<*-5T
- Ti i 3
YR MO DAY I ^
TBY f vr\\-^.vov- vAco"
to © o o cio o c © o e o © o,© o o©ooo©oco
nrri. 1 47T47-4-;, HO ». n » » »>"« 5J » ' » » «t « «3 «. » » •? «• «5
SOURCE SAMPLE REQUEST & REPORT
(MUST BE FILLED OUT FOR EACH TEST RUN)
IDENT. LAST IDENT. ^2^
SED £>-TT - oo'2 - C.02. NO. USED ^' 77- QQS - faf^r
.v-^^^vtvC YJV-CIP^
. (USE TABLE A)
ANY \ *^V_ )Co KJ.A O-AV\C*

1 INf?
00



DESCRIPTION OF
SAMPLE OR SAMPLE
FRACTION
hAv,'-\ S>o^,u-\o2. (\r>'iWO T?u*3-F
vx • \ -s \riVs - toa-Uok ^WSoSvA
yW,cV ^r^r.U- WV2 I *L^O 5^« ^ P

V\ ' v ^ ^^ - voa UV'A^ "vl^*3-o Uj
? W ^\ K" ^) ^ v u a o-,)
^~-D u\ xV.. C-T'V^
(^v,;^^ S>D,"TA^ -\\-^ I,-;A> R^AS-K
N^IN^aV Sp^T AS ' \\1 KlUrAA ^U** "S-k
KA 	 ,V ^SrrnoVc " \o
rn«'WFMT<;
UNIT PROCESS OPERATIC
AIR POLLUTION CONTRC
FUEL USE
D INLET D 0
GAS VOLUME SAMPL
(METER VOL IN FT^
SAM
WT
(SOLID)
MG



.^
^




2- CvA.^ 'Sv^S^Kv.iotel
PLE
VOL
(LIQUID)
ML
4So
5\o
<4Ro
4HS
A1S
Soc->
\uo
5»30
Sr,t-,
Soo
N
1
D
JTLET
-n
i
e i o ! o o o © ' o ! o 9 o o
TEST NO "^ 1
RUN NO


•
•

\
ANALYSIS REQUESTED - GENERAL COMMENTS
(APPROX CONCENTRATIONS - POSSIBLE INTERFERENCES
ETC) (INDICATE SPECIFIC ANALYSIS ON BACKSIDE)
^«vA V-O-- "Pje-^^r*
- "\^..AAVo\x'o^ tWW.-,
^ \
\v
VV
W
•v
OcJvA VUrv^ P^r<,'^
T^tv A V« v^ v ^ ' t^"ii<^'' •*-
r«_ o^v
• \~J v *^T »\\ fl.'^V O K V\iri f\\ \A*~*\.fr\ ..
v» '
II


L .MI 'f
SAMPLING
CONTRACTO
DATE OF REQW
EPAlDUR)245'
R

T-I - REQUEST // <^/ J
pnniF^T nFFir.FR X^c^^^ V^A^Wa^ RFVIFWFD BY r/oS^-' . ^^^i^ 	
(IF APPLICABLE) '
"ST 4/7 \ /Tf OATF AN4I YSIS RFOIIFSTPn DATE OF RFOUFST


(TO BE FILLED IN BY SSFAB)

\
= c
©
O
e'!
o

1«l
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r j
|O i

:l
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"J6>
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1 1
1 !
O
t- I
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50^


-------
APPENDIX B.  CALCULATIONS

-------
                                APPENDIX B
                               CALCULATIONS
                                 CONTENTS
                                                                       Page
B.I  Degreasing Emission Summary 	 B-l
B.2  Cold Cleaner Emissions 	 B-3
     B.2.1  National Cold Cleaner Emissions (1974)  	 B-3
     B.2.2  Emission Rate Per Cold Cleaner  	 B-4
     B.2.3  Projected Emission Reductions 	 B-5
B.3  Open Top Vapor Degreaser Emissions 	 B-7
     B.3.1  National Open Top Vapor Degreaser Emissions  (1974)  	 B-7
     B.3.2  Emissions Per Average Unit  	 B-7
     B.3.3  Projected Emission Reductions 	B-7
B.4  Conveyorized Degreaser Emissions 	 B-9
     B.4.1  National Conveyorized Degreaser Emissions  (1974)  	 B-9
     B.4.2  Emissions Per Average Unit  	 B-9
     B.4.3  Projected Emission Reductions 	 B-9
B.5  Degreasing Waste Solvent Disposal  	 B-ll
B.6  Calculations Relating to Adverse Environmental Affects 	 B-13
     B.6.1  Increased Boiler Emissions  	 B-13
     B.6.2  Stabilizers in Chlorinated Solvents 	 B-14
     B.6.3  Utilities Consumption of Carbon Adsorbers  	 B-16
     B.6.4  Fuel Costs of Incineration for Manufacturing
            Cold Cleaners 	 B-17
B.7  References 	 B-18

-------
                                                       *3
B.I   DECREASING EMISSION SUMMARY, 1974  (All  units = 10  metric tons/yr)

     1,  Total Organic Emissions from Degreasing            700

         Cold Cleaning                    380               (55%)

         Open Top Vapor Degreasing        200               (28%)

         Conveyor i zed Degreasers          100               (14%)
         (25  CND & 75 CVD)

         Wiping Losses                     20               (3%)

     2.  Contribution to National HC  Emissions

         Degreasing  Emissions  (1974)  =  700    =  2 5%
         National HC Emission  (197b)     2lfiOO
          Degreasing  Emissions         =   700    = 4j%
          National  HC Emissions  from       1/000
          Stationary  Sources  (1975)

      3,   Solvent consumption data were collected from several  sources  and

 tabulated in Table B-l.   The consumption estimates  were averaged  to  estimate

 the solvent consumption  of each type of  degreaser.   These data were  the basis

 for our emission estimates.
                                       B-l

-------
                                    U.S.  Consumption of Dpg^e.ising Solvents
                                                Table B-l

                                        1974 (10  metric tons/year)


Solvent Type

Halogenated
I'richloroethylene 1
1,1,1 Trichloroethane
Perchloroethylene
Methyl ene Chloride
Trichlorotrifluoroet-hane
"otal '-
Aliphatic
Aromatic
bei.zene
Toluene
Xylene
Cyclohexane
Heavy Aromatics
Total
Oxygenated
Atones
Acetone
Methyl Ethyl Ketone
A \ c o h o 1 s
Butyl
Ethers
Total
TOTAL
Breakdown:
Vapor Deg. Solvents

Weighed
Average
vp+CC=Total

28+2: n53
°.Q+8? - . t>?
.11^3= 54
7 + i' 1= 30
20+lu- 30
/t + lb3=-tJ9
222

7
14
12
1
_12
4T5


10
8

5
6
19
726

- VD - 276 ^

1 2
Monsanto-S.A.D. U.S. Tariff Comm.
Tom Hoogheem-1974 Report for 1974
VD_ + CC_ = Total VD + CC_ = Total

157 142 + 8 = 150
90 + 78 = 168 73 +106 = 179
43 + 11 = 54 40 + 19 = 59
10 + 46 = 56 7 + 18 = 25
- = 17 - . = .
-
225

7
. 4
1 '' Ho
1 Data
-


10
7-5
No
30 Da t a
. 3
6
26.5

Expected Accuracy:
: 275 ±10 percent - VD = 275 +25

Dow Final

Report3
Survey for 1974
VD + CC_

103 + 39
110 + 63
41+9
7.5 +6.3
34 + 18
296 +135
















Ranges:
= 250 to
= Total

= 142
= 173
= 50
= 13.8
= 52
= 431




No
Data



10
8

7
_
~


300 T3T
Dow
Chart
for
1974
VD Only

J43
73
40
9
20
285




No
Data





No
Data




10 metric

Detrex Es
Pr
1975
VD

114
63
45
8
20
25T5"




No
Data





No
Data




ton/yr)

;t1mat
•oject'
1974
VD

124
53
40
6
18
241




No
Data












                                                                                                                       J.  S.  Gunnir£
                                                                                                                       Shell  Chemical
                                                                                                                       Solvent Bus.  Ctr.
                                                                                                                          No Data
                                                                                                                          218
                                                                                                                           12
                                                                                                                          No Data
Cold Clean.  Solvents ? CC = 153+222+46+29
                          = 153+222+75
                          = 153+297
                          = 450
±15%±30%±50% -  CC = (155±25) + (220 ±65) + (75± 35)
                   = (130 + 155 +  38) to (180 + 285 +  112)
                   = 323 to 557
                   = 4bO ±  127
                                                           R_9

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B.2  COLD CLEANER EMISSIONS
B.2.1   National  Cold Cleaner Emissions (1974)
     Given:  (a)  Gross cold cleaning solvent  consumption = 450 Gg/yr* 1974
             (b)  about 5% of this is from wiping operations, which are
             not considered cold cleaner (CC)  emissions
             (c)  about 25 Gg/yr of this is from conveyorized non-boiling
             degreasers (CND).  (See subsection B.4.1)
             (d)  Waste solvent disposal (WSD) amounts to 280 Gg/yr.
             Approximately 7% of this is incinerated or landfilled in such
             a manner that no emissions occur.   (See Section 3.1.4)
     Calculate:  Cold Cleaner Emissions Estimate
             450 = Gross cold cleaning solvent consumption
            - 25 = for wiping losses
            - 25 = CND losses
             400 = Cold cleaner emissions if all WSD evaporates
             - 20 = controlled emissions due to proper waste solvent disposal
             380 (+100) Gg/yr = estimated emissions from cold cleaners-1974
 *Gg =  103 metric tons
                                       B-3

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B.2.2  Emission Rate Per Cold Cleaner
     Given:   (a)  880,000 Maintenance cold cleaners  (1974)
                  340,000 Manufacturing  cold  cleaners  (1974)
                  1.22 x 106 Total  cold  cleaners  1974
             (b)  A manufacturing cold cleaner has twice  the  average emission
             of a  maintenance cold  cleaner.
     Calculate:   Individual  cold  cleaner emission rates
             (a)  380 (±100) Gg/yr     n  0,  ,.n no. M  ,
                  1.22Vlift units   = °'31  (i-°-08) M9^r  Per  urnt
                                    = 660 Ib/yr per unit
                                    % 100 (+20) gal/yr per  unit
             (b)  IF:   X =  average maintenance  cold cleaner emission
                       2X =  average manufacturing cold cleaner emission
                      Ta-j  =  national  maintenance  cold cleaner emissions
                      Ta2 =  national  manufacturing cold cleaner  emissions
                THEN:   X x  880 (xlO3) = Ta]
                       2X x  340 (xl()3) = Ta2
                       Ta1 + Ta2       = 380  (+J00)(xl03  metric  ton/yr)  in  1974
                AND:  Ta1 =215  (xlO3 metric ton/yr)
                       Ta2 = 165  (xlO3 metric ton/yr)
                        X =0,24 metric ton/yr = (490 Ib/yr)
                       2X = 0.48 metric ton/yr = (980 Ib/yr)
             (c)  "Safety Kleen"  maintenance  cold cleaners  and others:
                  Let X   = average emission from a  Safety Kleen  cleaner
                      X    = average emission  from other maintenance  cold  cleaners
                  Then:
                      X .   = 24 x 10  metric  ton/yr   _  0.17  metric  ton/sk cleaner-
                       SK         T40.000            ~  38f) lb/vr
                      Xo              =0.24  metric  ton=  530  Ib/yr
                                    B-4

-------
B.2.3 -Projected Emission Reductions*
      A.  Cold Cleaner System A
          Assumptions & Estimations:
          1.  Average typical cold cleaner emits about 0,3 metric tons/yr.
          2.  An average of 55% of cold cleaning emissions is due to
          evaporation of waste solvent.  This could be reduced to
              with excellent compliance
          30% with average compliance
          40% with poor compliance.
          3.  45% of  the  emissions occur  directly from the cold cleaner.
          20% is through  bath  evaporation (including  agitated & spray
          evaporation)  and  25% is through carry out.   Cover  closing  can  reduce
          bath  evaporation  from 20%  to 4% with excellent compliance
                                        9% with average compliance
                                        18% with poor  compliance.
          Drainage practice  could reduce  carry-out  from
          25% to 5% with  excellent compliance
                 11% with  average compliance
                 18% with  ooor  compliance.
       Conclusion:
           With excellent compliance system A could reduce emissions  by 100-10-4-5=
       80%.   With average compliance, emissions could be reduced by 100-30-9-11=
       50%,   With poor compliance, emissions could be reduced by 100-40-14-18=
       28%,
  *The previous  and  the  following  projected estimates represent the best engineering
  iudqement that can be  made  given the  limited  data  base.   These  estimates are
  not"to be interpreted  as  test data; thus, a wide range  is given for most
  estimates.
                                    B-5

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      B.  ^old Cleaner System B

          Note that excellent compliance would not vary much between systems

          A and B,

          Assumptions & Estimations—same as for system A except:

          1,  Mechanically assisted covers, the "major control  device" and

          spray specifications and agitation restrictions are estimated to

          reduce bath evaporation from 20% to 2% with  excellent compliance
                                              6% with  average compliance
                                             10% with  poor compliance


      Conclusion:

          With excellent compliance system B could reduce emissions by 100-10-25=

      83%,  With average compliance, emissions could be reduced by 100-30-6-11=

      53%.  With poor compliance, emissions could be reduced by 100-40-10-18=

      32%.

      C,  Cold Cleaners Using High Volatility Solvent

          Recommended controls would effect higher emission reductions on

      units using highly volatile solvents.  It is estimated that with average

      compliance emission reduction would increase to  55% for system A and to

      69% for system B.
Note:Table 3-14 in the Dow Report estimates emissions from a.typical,
maintenance cold cleaner,  Although the overall  emission rates  are on the high
side, the percentage of emissions from waste solvent evaporation (refilling)
carry-out and bath evaporation calculate to 58%, 28%,  and 16% respectively.  '
This compares reasonably with the previous estimates of 55%, 25% and 20% for
all types of cold cleaners, (considering that manufacturing, cold cleaners
tend to have a higher proportion of bath evaporation than do maintenance
cleaners).
                               B-6

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B.3  OPEN TOP VAPOR DEGREASER EMISSIONS
B.3.1  National Open Top Vapor Degreaser Emissions (1974)
      Gross vapor degreasing solvent consumption is 275 (+25) Gg*/yr.
Approximately 200 (+20) Gg/yr of this is from Open Top Vapor Degreasing (OTVD)
and 75 Gg/yr is from Conveyorized Vapor Degreasing (CVD).  These estimates are
similar to previous estimates that CVD emit about 65 Gg/yr and OTVD, 210 Gg/yr.
B.3.2  Emissions Per Average Unit
      1.  If there are 21,000 OTVD  (1974), an average OTVD would emit about
200  (+20) Gg/yr ^ 21,000 = 9.5 MT/yr.
                                                        2                2
      2.  If an average OTVD has an open area 18  (+3) ft  =  1.67 (+0.3) m
                                                p
then emission  per area would average 5,7 MT/yr-m   (These averages probably
are within +_ 25 percent accuracy.)
B.3.3  Projected Emission Reductions
      Estimates have been made of the total control efficiencies (n+), the control
efficiencies from improved operating practices  (r^) and control efficiencies
from control equipment  (nfi) for control systems A and B.

no
ne
Approx. n+
System A
Compliance
poor average
15 25
20 30
32 47
30 45
excellent
35
40
61
60
System B
Compliance
poor average
20 30
30 45
44 62
45 60

excellent
40
60
76
75
     Note:   (1 - n+) = 0  - -n0) (1  -
 *Gg = 10J  metric tons
                                     B-7

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2.  Given 9.5 mT/yr per average OTVD,

           Emission Per
           uncontrolled             Emission  per  controlled  unit
               unit	poor    average      excellent
System A
System B
9.5
9.5
6.5
5.3
5.2
3.8
3.7
2.4
                               B-8

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B.4  CONVEYORIZED DEGREASER EMISSIONS
B.4.1   National Conveyorized Degreaser Emissions (1974)
      Given:   (a)  Emissions from conveyorized vapor degreasers (CVD) is
              75 Gg*/yr.
               (b)  It is estimated that between 25 to 35 percent of the
               conveyorized degreasers are Conveyorized Non-Boiling Degreasers
               (CND),8  This estimate appears somewhat high, thus choose 25 percent
               which is on the lower end of the range,
      Calculate:
               (a)  CND emit 25 Gg/yr
               (b)  CVD emit 75 Gg/yr
               (c)  Total conveyorized degreaser emission are  100 Gg/yr.
 B.4,2   Emissions Per  Average  Unit
      1.   Estimate that  there are about  3170  CVD  and  530 CND  nationally in
 1974.
     9,10
      2   An average emission rate for a CVD would be 75.000 Mg/yr _ 03 7  MT/vr
                                                       3,170 units     '     IJ
      3.   Average emission from a CND would be 25,000 = 47^ MT/yr.
                                                3O\y
B.4.3  Projected Emission Reductions
      Estimates have been made of total control efficiencies (n+), the control
efficiencies from improved operating practices (n0) and the control efficiencies
from control equipment for control systems A and B.
Control
Efficiencies
(n) (*)
Improved nQ
operation
Control n
equipment
Total n+
approximated
System A
Compliance:
poor average excellent
20 25 30
- - -
20 25 30
- - -
System B
Compliance:
poor avg. excl .
20
40
52
50
25 30
50 60
62.5 72
60 70
Note: (l-n+) = 0~O 0-np)
^ U C n rt
          *Gg = 10  MT

-------
2.  Emission control for typical units:


Conveyorized Vapor Deg.
Con. Non-boiling Deg.
••^
Average CD
Emission rate (MT/yr)
Uncontrolled
24
^48
27
Controlled with
System A
18. (17 to 19)
36 (34 to 38)
20 (19 to 21)
Controlled with
System B
9 (7 to 11)
18 (13 to 23)
10 (7.5 to 13)
                               B-10

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B.5  DECREASING WASTE SOLVENT DISPOSAL
     It has been estimated that 280 (±80) thousand metric tons/yr of waste
solvent are disposed of by the solvent metal cleaning industry in 1974.  The
calculation is based on the following assumptions and estimates.*
     Assumption^
     1.  Percent virgin solvent that becomes waste solvent for each category
of degreasers.  (EPA and Dow Chemical estimates)
     a.  Degreasing  industry collectively         30% to 50%
     b.  Cold  cleaners collectively               45% tO 70%
     c.  Maintenance cold  cleaners                50% to 75%
     d.  Manufacturing cold  cleaners              40% to 60%
     e.  Conveyorized vapor  degreasers            10% to 20%
     f.  Open  top  vapor  degreasers                20% to 25%
      2.   Virgin solvent consumption.   (EPA  estimates)
      a.   Cold cleaners  (excluding  10%  as  wiping  losses)
          Maintenance (56%)                          215,000  Mt/yr
          Manufacturing  (44%)*                      165,000  Mt/yr
      b.   Open top vapor degreasers                 200,000  Mt/yr
      c.   Conveyorized degreasers (vapor and cold)   100,000  Mt/yr
      Waste Solvent Estimates
      1.   Maintenance cold cleaners               - 134,000  Mt/yr
          (or 215,000 x .625 = 134,000 Mt/yr)
      2.   Manufacturing cold cleaners             =  83,000  Mt/yr
          (165,000 x  .50)
      3.   Conveyorized  vapor degreasers           =  15,000  Mt/yr
          (100,000 x  .15)
  *The accuracy of the estimates  is not  expected  to  be better than + 30%,
                                  B-ll

-------
4.  Open top vapor degreasers               =  45,000 Mt/yr



    (200,000 x .225)                          	



                       Total waste  solvent  =  277,OOOMt/yr(+85,000 Mt/yr)
                            B-12

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B.6  CALCULATIONS RELATING TO ADVERSE ENVIRONMENTAL EFFECTS
B.6.1  Increased Boiler Emissions-Computation
     The objective is to determine the magnitude of increased boiler emissions
caused by use of a carbon adsorber.  The carbon adsorber generally has the
highest energy consumption compared  to that of other control devices.  A
typical carbon adsorber could be  a Vic #536 AD.  According  to the J. L. Thompson
test report  by Dow,  the steam usage  may  be 113 Ib. per desorption cycle which
converts  to  113,000  Btu/cycle.  Taking an average  of two desorption .cycles
per day,  the consumption  becomes  about 225,000 Btu/day or  28,000 Btu/hr.
      Assume  that high  sulfur fuel oil were to be used to fire the boiler.   Take
 residual  fuel oil  with 2% sulfur  content.  According to  "Compilation of Air
 Pollution Emission Factors"  (AP 42)  such fuel  combustion would  emit the  following
 pollutants per 103 gal.  fuel oil:  310 Ib SO,,,  23  Ib particulates,  60 Ib  NOX,
 4 Ib CO and 3 Ib HC (hydrocarbons).
      Relate the emissions to an  hourly emission rate.   To  produce 28,000 Btu/hr
 at  75% conversion efficiency would  require 37,000 Btu/hr of fuel.  Choosing
 #5  fuel oil, we have 148,000 Btu/gal.  Thus,; increase* fuel consumption would
 be  about 0.25 gal/hr.*   Increased pollutant emission would then be 0.08 Ib/hr
 (0.036 kg/hr) S02,  0.005 Ib/hr (0.002 kg/hr) particulates, 0.008 Ib/hr
 (0.00035 kg/hr) NOX, 0.0005 Ib/hr (0.0002 kg/hr)  CO and 0.0004 Ib/hr
 (0.0002  kg/hr)  HC.
      Compare the  increased  emissions to  the emission reduction caused by the
  carbon adsorber.   A typical adsorber  system that  is properly designed and
  maintained may save 50 gal/wk * 15  Ib/hr =  6.8 kg/hr.   Thus,  the total  increased
  boiler emissions equals about 0.6% of the emission reduction  caused by a typical
  carbon adsorber.

  *37.000 Btu/hr~~T Q 25    1/hr  of  fuel
    148,000 Btu/ga!   u<^  y
                                   B-13

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B,6,2  Stabilizers in Chlorinated Solvents
                                       Fish

Trichloroethylene
Epichlorohydrin
Butylene Oxide
Glycidol
Acrylonitrile
Diisopropylamine
Triethylamine
Ethyl Acetate
Diisofautylene
Thymol
N -Methyl Pyrrole
Acetaldehyde
Dimethyl
Hydrazone
Tetrahydrofuran
Sec. Butanol
N-Propanol
1,1,1 Trichloroethane
1,2 Butylene Oxide
Butylene
Nitroethane
Nitromethane
3-Methoxy
Propronitrile
1,3-Dioxolane
1 ,4-Dioxane
N -Me thy! -Pyrrole
Toluene
Methyl Ethyl
Ketone
Isobutyl Alcohol
Tertiary Butanol
Sec. Butanol
Acrylonitrile
Acetonitrile
Isopropyl Nitrate
Tertiary Amy!
Al cohol
1 ,3,5 Trioxane
2 Methyl -3-Butynol -
2
JSl. = slightly and s.
TDL - oral human
Solubility
in water
x \ -

6

25-58

si.s*
5.5
9
SI.S
sTs




100
13
S

10

non-mi sc.
10


100
100

S
27-37

10
^20
13

100

partially
S



= soluable
Toxicity BOD-20 Boiling Point
ppm x % of Theory °C

15


20

30
>1QO
1





>100
>10Q,
1900*

>100


1000


300
>100

3100+
>1000

>100

>100

>100



14**


Concentration
nrnmri fns\ ft sv u.«t 1

50
50-60



0
80
0





45
85


60

115
30


0
30

60 112
75 80

80
£120
85
75
82



115


giving 50% fatality to rat:
                                  B-14

-------
    %          Fish
Solubility   Toxictty
 in water  x  x  ppm
Methyl ene Chloride
Propylene Oxide
Butyl ene Oxide
Amy! ene
Cyclohexane
Methyl ene Chloride
Perch! oroethylene
Thymol
4-Methyl
Morphol ine
P-Tertiary Amy!
Phenol
3-N-Propoxy
Propionitrile
Isopropyl Alcohol
Epichlorohydrin
Diallylamine

40-60

Sl.S
0
2

Sl.S

100

partially


100
6

                                                >100

                                                  30

                                                21001
                                                             BQD-2Q     Boiling  Point
                                                            of Theory v      °C
                             75

                              5
          34
Sl.S
100
partially
100
6


2700f
3100f
>100 80
15 50


115

82

112
                           Estimated Stabilizer Emissions into Sewer
                                                Approximate
                               Stabilizers in   Solubility
                               Solvent blend        %
                             gal/wk
Sewer Emission Rate
       m3/wk
    Worst  Case:


    Average Case:

    _—_——————



    Typical Emission Control:
    2%
                               0.2
                                                                         0.004
      0.0008
                             Atmospheric Emission Reduction
                            50 gal/wk
               0.2 m°/wk
                                               B-15
54

-------
                                    B.6.3  UTILITIES CONSUMPTION OF CARBON ADSORBERS
Reference to
Dow Report
Appendix:
C-10
C-8
C-9
C-ll
Average
Test Site
Vic Manuf. Co.
Super Radiator Co.
J. L. Thompson Co.
W. Electric Co.

Model
Adsorber
Vic #
572AD
554AD
536AD
536AD

Ventilation Rate
Both Beds Adsorbing
(cfm)
5500
£3000
940
£1300
2700
Solvent
Recovered
(qal/wk)
70
*
i
25 to 50*
85

Water
Consumption
(103 gal/yr)
630
1380
230
1380
900
Steam
Consumption
(106 Btu/yr)
310
380
54
520
320
Electricity
(103 kw)
30
30
\
4'
13
19
*Defective control systems
                                                                  B-16

-------
B6 4  Fuei_Costj>fJMS!!2ti°5-^^
     Assume a ventilation rate of 50 cubic ft/minute/ft2  of open top area,
an average tan. area  of 6 f t2 , 8 hours of operation per weekday and 2 1/2
dollars/million BTU fuel cost.  Using an air density of 0.075 Ibs/ft  , a
specific heat of 0.25 BTU/1bs°F for  air, and a maxin™ temperature of 800°F,
,„ approximate annual fuel  cost would be about $1200/year, as su^arized
below.                                                                    6
      Exhaust volume  .  300 cfm x 60 min/hr x 8  hr/day  x 240 day/yr - 35 x 10
                       ffrVyr
      - — '  fesVoer5 Wft  X  '
      Annual fuel cost - 485 x  vfi BTU/yr x 2.50 $/!# BTU - 1215 5;  1200 $/yr
                                      B-17

-------
   B.7   REFERENCES
   1.   Information provided by Tom Hoogheem, Monsanto Research Corp., Dayton,
      Ohio, by telephone to J. C, Bellinger, EPA, on December ] and 6, 1976.
   2.  Surprenant, K. S. and Richards, D. W. of Dow Chemical Company, "Study
      to Support New Source Performance Standards for Solvent Metal Cleaning
      Operations," 2 vol., prepared for Emission Standards and Engineering
      Division (ESED),  under Contract # 68-02-1329,  Task Order #9, June 30, 1976,
      PP.  7-3.
  3.   Ibid.
  4.   Kearney, T.  J,, Detrex  Chemical  Ind.,  letter to J.  C.  Bollinger,  EPA,
      January  9,  1976.
  5.   Information  provided  by  J.  S. Gunnin,  Shell Chemical  Co., Houston, by
      telephone to J, C, Bollinger, EPA, September 16, 1976.
  6.  Op, Cit., Surprenant, K. S., pp. 7-3.
  7.  Bollinger, John C., "Trip Report - ASTM, Consultant and Two Waste Solvent
     Plants," memo to David R. Patrick reporting on trip to ASTM D-26 meeting
     of January 26, 1977.
 8.  Bollinger, J. C.,  "Maximum Impact of NSPS on 1985 National Degreasing
     Emissions," December  1975.
 9.  Ibid.
10.  Surprenant,  K.  S., Op. Cit.
11.  Ibid.  pp. 7-3.
                                    B-18

-------
TECHNICAL REF'ORT DATA
(Please read Instructions on tlir reverse before completing)
REPOR r NO. 2.
PA 450/2-77-022 	 |_
T ITLE AND SUBTITLE
Control of Volatile Organic Emissions from
lOlvent Metal Cleaning
AUTHOR(S)
lohn C. Bellinger*
effrey L. Shumaker, ESED
PERFORMING ORGANIZATION NAME AND ADDRESS
. S. Environmental Protection Agency
)ffice of Air and Waste Management
)ffice of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
. SPONSORING AGENCY NAME AND ADDRESS
3. RECIPIENT'S ACCESSION- NO.
5. REPORT DATE
November 1977
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
OAQPS 1.2-079
10. PRCIGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
^SUPPLEMENTARY NOTES 	
*No longer with EPA
      This  report  provides the necessary guidance  to  control  emissions of
 volatile organic  compounds (VOC) from solvent metal  cleaning operations.
 Emissions  are  characterized and reasonably available control  technology'(RACT)
 is defined for each  of the three major categories of solvent metal  cleaners-
 :old cleaners,  open  top vapor degreasers, and conveyorized degreasers.
 Information on  the cost of control, environmental impact  and enforcement
 issues is  also  included.
                               KEY WORDS AND DOCUMENT ANALYSIS
                 DESCRIPTORS
Mr Pollution
Solvent  Metal  Cleaning (Degreasing)
Emissions  and Controls
Regulatory Guidance
                                             b.IDENTIFIERS/OPEN ENDED TERMS
 Air Pollution  Controls
 Stationary Sources
 Organic Vapors
 Degreasing
                                                                          COSATI 1-icld/Group
       iUTION STATEMENT
                                              19 SECURITY CLASS (Tim Report)
                                               Unclassified
                           21 NO. OF PAGES
                               203
 Unlimi ted
2O. SECURITY CLASS (This pagcf
 Unclassified
22 PRICE
E!PA Form 2220-1 (9 73)

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