United States       Office of Air Quality       EPA-450 3-79-033
            Environmental Protection   Planning and Standards      Guober 1979
            Agency         Research Triangle Park NC 2771 1
vvEPA      Review of Standards
            of Performance for
            Electric Arc Furnaces
            in  Steel  Industry

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                                          EPA-450/3-79-033
    Review of Standards of Performance
for Electric  Arc  Furnaces in Steel Industry
                 Emission Standards and Engineering Division
                    EPA Project Officer: Reid E. Iversen
                                    P.O. Environrr ;"•'•
                                    j  ,' o a o f  i-j -i' -* - •"->
                                    WO S. Dearborn L
                                    Chicago, IL  6060^t
                  U.S. ENVIRONMENTAL PROTECTION AGENCY
                     Office of Air, Noise, and Radiation
                  Office of Air Quality Planning and Standards
                  Research Triangle Park, North Carolina 27711

                           October 1979

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This report has been reviewed by the Emission Standards and Engineering
Division, Office of Air Quality Planning and Standards, Office of Air, Noise,
and Radiation, Environmental Protection Agency, and approved for publica-
tion . Mention of company or product names does not constitute endorsement
by EPA. Copies are available free of charge to Federal employees,  current
contractors and grantees, and non-profit organizations - as supplies permit
from the Library Services Office, MD-35, Environmental Protection Agency
Research Triangle Park, NC 27711;  or may be obtained, for a fee, from the
National Technical Information Service, 5285 Port Royal Road, Springfield,
V f\
                     Publication No.  EPA-450/3-79-033
                                   11

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                         TABLE OF CONTENTS
1.0   INTRODUCTION                                                      1-1

2.0   SUMMARY                                                           2-1

2.1   Latest Control Technology for Electric Arc Furnace Shops          2-1
2.2   Rationale for Review of the Mew Source Performance
      Standards for Electric Arc Furnaces                               2-2
2.3   Inclusions and Exemptions in Revised New Source
      Performance Standards                                             2-3
2.4   References for Section 2.0                                        2-3

3.0   ELECTRIC ARC FURNACES IN THE STEEL INDUSTRY                       3-1

3.1   General                                                           3-1
3.2   Description of Process                                            3-5
3.3   Emission Sources                                                  3-8
3.4   References for Section 3.0                                        3-10

4.0   STATUS OF EMISSION CONTROL TECHNOLOGY FOR ELECTRIC ARC FURNACES   4-1

4.1   Capture Systems and Control Devices                               4-1

      4.1.1  Canopy Hoods in a Shop with a Sealed Roof                  4-1
      4.1.2  Direct Shell Evacuation in a Shop with  Either
             Building Evacuation or Canopy Hoods and a Closed Roof      4-3
      4.1.3  Semi-enclosed Furnaces with Direct Shell
             Evacuation, Canopy Hoods and Tapping Hoods                 4-3
      4.1.4  Side Draft Hoods                                           4-7
      4.1.5  Furnace Enclosure                                          4-7
      4.1.6  Brusa Closed Charging System                               4-15
      4.1.7  Canopy Hoods in Combination with Natural Ventilation
             through Open Roof                                          4-15
      4.1.8  Direct Shell Evacuation in Combination with Natural
             Ventilation through Open Roof                              4-17
      4.1.9  Building Evacuation in Shop with Closed Roof               4-20
      4.1.10 Direct Shell Evacuation in Shop with Canopy Hoods
             with Open Roof

4.2   Effectiveness of Various Control Devices                          4-23
4.3   Control Technology Applicable to New Source Performance
      Standards for Electric Arc Furnaces                               4-24
4.4   Control Technology in Current Use in Mew Electric
      Arc Furnace Shops                                                 4-24
4.5   Potential New Control Technology                                  4-26
4.6   References for Section 4.0                                        4-27

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5.0   CURRENT STANDARD FOR ELECTRIC ARC FURNACES IN STEEL INDUSTRY       5-1

5.1   Electric Arc Furnace Exemptions from New Source
      Performance Standards                                              5-1
5.2   New Source Performance Standards for Particulate Emissions         5-2
5.3   Problems with New Source Performance Standard for
      Visible Emissions                                                  5-3
5.4   References for Section 5.0                                         5-4

6.0   CURRENT STATUS OF ELECTRIC ARC FURNACES IN STEEL INDUSTRY          6-1

6.1   Emission Data Since New Source Performance Standards
      Promulgation                                                       6-1
6.2   Comparison of New Control Technology and Current
      New Source Performance Standards Emission Control
      Performance                                                        6-2
6.3   Future Growth                                                      6-4
6.4   Justification to Revise New Source Performance Standards           6-4
6.5   References for Section 6.0                                         6-5

7.0   RECOMMENDATIONS FOR REVISION OF STANDARDS                          7-1
                                   iv

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                      LIST OF ILLUSTRATIONS

Figure Mumber                                                       a^e

    3-1      Flow Diagram of an Iron and Steel Plant                3-2

    3-2      Steel Production Trend by Type of Furnace              3-3

    3-3      Electric Arc Furnaces                                  3~6

    3-4      Electroslag Remelting Furnace                          3-9

    3-5      Reduction of Slag  Inclusions                           3-9

    4-1      Canopy Hood with Closed Roof  System                    4-2

    4-2      Direct Shell Evacuation, Building  Evacuation
             with Closed Roof System                                4-4

    4-3      Direct Shell Evaucation, Canopy  Hood  with
             Closed Roof System                                    4-4

    4-4      Semi-Furnace Enclosure  System                         4-6

    4-5      Side Draft  Furnace System                              4-8

    4-6      Total  Furnace  Enclosure with  Proprietary               4-9
    through Steam  Scrubber                                      through
    4-10                                                            4"u

    4-11    The Brusa Charging and Preheating System               4-16

    4-12     Canopy Hood with Open Roof System                      4-18

    4-13     Direct Shell  Evacuation with  Open Roof System          4-18

     4-14     Building Evacuation System                             4-21

     4-15     Direct Shell  Evacuation,  Canopy Hood with Ooen Roof    4-21

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                              TABLE

Table Number
Table 6.1    Comparison of New Control Technology and  Existing
             NSPS Control Technology for  EAF's  in the
             Steel Industry                                          6_3
                                   VI

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                          1.0  INTRODUCTION



     Section 111 of the Clean Air Act, "Standards of Performance for New



Stationary Sources," requires that "The Administrator shall, at least



every four years, review and, if appropriate, revise such standards



following the procedure required by this subsection for promulgation of



such standards."



     The purpose of this study is to review the current new source



performance standards (NSPS) for electric arc furnaces (EAF's) in the



steel industry and to assess the need for revision on the basis of



developments that either have occurred or are expected to occur in the



near future.  This report addresses the following issues:



     1.   Utilization of EAF's in the steel industry.



     2.   Review of the best demonstrated control technology for emission



         control.



     3.   Review of existing and new control technology since promulgation.



     4.   Review of EAF's that are exempt from the standard.



     5.   Review of problems related to compliance with NSPS.



     6.   Analysis of available FAF particulate and visible emission test



         results.



     Based on the information developed in this study, specific recommendations



are made for changes in the current NSPS.
                                 1-1

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                        2.0  SUMMARY
     Control technology for EAF shops has been improved and refined
since the promulqation of the original NSPS.  Fugitive emission control
technology, especially for charging and tapping emissions, has been
developed, and furnace emissions can be captured more effectively.
These improvements afford a more stringent control of visible emissions
than required by the present NSPS.  Some compliance test problems have
developed in enforcing the visible emission portion of the NSPS.
2.1  LATEST CONTROL TECHNOLOGY FOR ELECTRIC ARC FURNACE SHOPS
     There are several control technologies that EAF shops can use, but
only a few recent ootions are available that can be considered best
demonstrated control technology for both process and fugitive emissions.
The combination of direct shell evacuation, canopy hoods, fugitive dust
pickup system, and a closed roof aopears to be the most overall efficient
system.  Another commonly used system includes a canopy hood, fugitive
dust pickup system, and a closed roof.  Total enclosure of the furnace,
a  new concept since the NSPS was promulgated in 1974, can potentially
capture all process and fugitive emissions  (charging and tapping).
Since these emissions do not mingle with other shop emissions, enforcement
issues are  reduced  (See Section 5.3).  Partial or semi-furnace enclosure
is  another  concent which encloses  the furnace by  four walls with  the top
open, so  that a crane can reach the  furnace area.  The walls, acting as
a  "stack",  force the emissions  to  rise from the furnace into  the  overhead
canopy hoods.  The  EAF shop  itself can also have  a closed roof.
                                2-1

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     One European system preheats the scrap feed with the hot furnace
gases while scrap is fed continuously to the furnaces.  This system
offers the advantage of confining the charging emissions to the preheater
(ducted to a control device) and thus permits a simple collection system.
The scrap size for this system must be controlled.  Only one U.S. plant
(foundry) uses this type of system.  The systems previously described
usually have baghouses as the control devices.  The one furnace enclosure
system used in the U.S. uses a proprietary scrubber system, but a baghouse
could be used effectively on this system.
2.2  RATIONALE FOR REVIEW OF NEW SOURCE PERFORMANCE STANDARDS FOR ELECTRIC
     ARC FURNACES
     The rationale of the current NSPS that closed roofs, building
evacuation, and limited control for tapping or fugitive emissions was
too costly and energy intensive, or that technology was not developed
may not be valid today.  Regulations currently being developed by some
local agencies appear to be more stringent than the NSPS.  Also, more
stringent control  (than required by NSPS) may be  necessary to prevent
significant deterioration of the air quality or to meet off-set policies
in specific areas.  The technology trend is toward the use of sealed
roofs, canopy hoods, and a  fugitive dust pickup system,  Control technology
developed and demonstrated  for fugitive emissions mainly from tapping
and charging is the major improvement  in controlling visible emissions.
Although only one  official  NSPS  compliance test has been carried out
since promulgation of NSPS, some unofficial test  data  indicate that
emissions from certain new  furnaces are below the NSPS  for particulates
                       1-4
and visible emissions.
                                      2-2

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2.3  INCLUSIONS AND EXEMPTIONS IN REVISED NSPS
     A speciality type furnace known as the argon-oxygen decarbonization
(ADD) furnace should be included in the NSPS because this furnace is a
significant source of particulate and visible emissions.  Although AOD
furnaces are not electric furnaces, they are an integral part of an EAF
shop and should, therefore, be considered for inclusion under an EAF
standard.  This change may require alternation of the definition of the
affected facility portion of the NSPS.
     Several other speciality electric arc furnaces used in the industry
should officially be listed as exempt from the NSPS. Electric arc furnaces
using prereduced pellets should also be reviewed in detail to determine
whether their exempt status should be continued. These findings indicate
revision of the current NSPS should be considered.
2.4  REFERENCES FOR SECTION 2.0
1.   Region  IV, 1977.  Memo dated February 28, 1977 to Drew Trenholm,
     ESED from Bruce Miller, Region  IV.
2.   Blair and Martin, 1978.  EAF Fume Control at Lone Star Steel Company,
     Lone Star, Texas.
3.   Reinke, J.M., 1976.  Letter dated November 1, 1976 to Mr. Michael Maillard.
     Wayne County Department of Health, Air Pollution Control Division.
     Detroit, Michigan.
4.   Adams,  J.I., 1978.  Letter dated  September 20, 1978 to
     Mr. John E. McGrogan,  P.E., Department of Environmental  Resources,
     Bureau  of Air Quality.  Wernersville, Pennsylvania.
                                       2-3

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                3.0  ELECTRIC ARC FURNACES IN STEEL INDUSTRY
3.1  General
     Major sources of air pollution in the steel industry are the basic
oxygen process, electric arc, and open hearth steel production furnaces;
blast furnaces; and coke and sintering plants (Figure 3-1).  All will
emit large quantities of air pollutants (primarily particulate matter)
if not properly controlled.  The first standards of performance for
electric arc furnaces were Promulgated in October 1974.  This review was
conducted to determine whether existing standards for electric arc
furnaces should be revised as required in Section lll(b) of the Clean
Air Act as  amended August  1977.
     Standards for the basic oxygen process  furnace  (BOPF) were developed
before those for  the electric arc  furnace (EAF) because the BOPF was
projected to experience  the  greatest  share of the  future growth in steel
production.  Electric arc  furnaces will also participate in the growth
because of  the increased use of  scrap to  produce steel.  These  projected
growth rates result  from increased demand for steel,  replacement of
obsolete  steel producinn furnaces, and higher energy  costs.  Figure 3-2
shows  trends for  the oast  15 vears in the production  of  steel  from these
three  types of furnaces.
      A BOPF can produce  steel  at a greater  rate than the other types of
furnaces.   Since  the BOPF  has  no exterior source  of heat,  it must  be
operated  in conjunction  with a blast  furnace.   Because the BOPF requires
a high percentage of molten pig  iron  as  part of the charge, the amount
 of steel  scrap that can be recycled  by the  BOPF shops is limited.   In
 contrast  the EAF  is very attractive  because it  can accept  a charge that
 is all scrao.
                                   3-1

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                  IRON OR
CO
ro
                                 X
                                                    HOT METAL
                                                     HOLDER
                                                     SCRAP
                                                                                      CONTINUOUS CASTING

                                                                                             y     BILLETS
               Sintering Machine
OPEN HEARTH
  FURNACE
                            _ SOAKING
                          CTg  PIT
                         INGOTS
                                                                  ELECTRIC-ARC
                                                                    FURNACE
                                        Figure 3-1. Flow-diagram of an iron and steel plant.

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1963    1965   1967   1969    1971    1973   1975   1977
                        YEAR

Figure 3-2. Steel production trend by type of furnace.
                  3-3

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 In fact,  about 98 percent of the steel  produced by EAF's  in 1977 was
 recycled  steel scrap.2  EAF's are also  particularly suited to production
 of alloy  steels where only small  batches  are  needed.
      The  steel industry categorizes  the majority of electric  furnaces
 into electric arc (EAF),  argon-oxygen decarbonization  (ADD),  vacuum arc
 remelting (VAR),  vacuum induction melting (VIM), consumable electrode
 melting (CEM), and electroslag remelting  (ESR)  furnaces.   Each  has  a
 specific  function for producing different types  of steel.   The  existing
 NSPS exempts  AOD,  VAR,  VIM,  and ESR  electric  furnaces  because the tonnages
 produced  were found to  be  significantly less  than  the  production  from
 conventional  electric arc  furnaces.  Some differences  are  involved  in
 the  operation of  these  furnaces,  and the  emission  rates may vary  considerably,
 For  these reasons,  the  furnaces were made exempt from  the  NSPS.
      In 1977,  electric  arc furnaces  produced  27,882,000 tons  of steel.
 Of this amount, 70  percent was  carbon steel,  23  percent was alloy
 steel, and 7  percent  was stainless steel.   This  production accounts  for
 18 percent of the carbon steel, 42 percent of the alloy steel, and  all
 of the stainless  steel  produced in all furnace types.
      In 1977,  the 303 EAF's  in  the United States were operated by 85
 companies  at  114  locations.  Furnace capacity ranges from an almost  toy-
 scale 3 tons  to 400 tons, with about 50 percent of the furnaces under 49
 tons, 25 percent at 50 to 99 tons, 9 percent at 100 to 149 tons, 10
 percent at 150 to 199 tons, 5 percent at 200 to 300 tons,  and 1  percent
over 301  tons capacity.  Larger furnaces are usually located in integrated
                                   3-4

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steel mills.   Many of the smaller furnaces are in small  plants that
produce a limited variety of products or small quantities of specialty
steels.
     Among the factors now tending to increase EAF steel production are:
increasing blast furnace energy costs, larger supplies of steel scrap,
growing use of specialty steels, additional mini-steel plants that
normally use EAF's exclusively, and adoption of ultra-rapid steel melting
technology from Japan and other foreign countries.
3.2  Description of the Process
     Electric arc furnaces are cylindrical refractory-lined vessels with
carbon electrodes that are lowered through the furnace roof (Figure 3-3).
With the electrodes retracted, the furnace roof can be rotated aside to
permit the charge of scrap steel to be dropped into the furnace.  Alloying
agents and slag materials are usually added through the doors on the
side of the furnace.  Some smaller or older furnaces are charged through
these side doors.  Current is applied to the electrodes as they descend
into the furnace.  The scrap is melted by the heat generated by the arc
as it shorts between the electrodes and the scrap.  The slag and melt
are poured from the furnace by tilting it.
     The production of steel in an EAF is a batch process.  Cycles or
"heats" range from about 1.5 to 5 hours to produce carbon steel and from
about 5 to 10 hours or more to produce alloy steel.  Scrap steel is
charged to begin a cycle, and alloying agents and slag materials are
added for refining,  ^ach cycle normally consists of alternate charging
and melting operations, refining  (which usually includes oxygen blowing),
and tapping.

                                  3-5

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      CARBON
    ELECTRODES
                                                    SCRAP,
                                                  LIMESTONE,
                                                   AND LIME
FURNACE
 ROOF

   MECHANISM THAT LIFTS
     AND PIVOTS ROOF
FURNACE
        /ALLOY AND SLAG
            ADDITIONS
                               CHARGING
           SLAG
                                                   BOLTEH
                                                   STEEL
                      DESLAGGING AND TAPPING
                  Figure 3-3.  Electric-arc steel furnace.
                               3-6

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     ADD furnaces are refractory-lined vessels generally U-shaped like
basic oxygen furnaces.  They are used to refine hot metal from EAF
furnaces.  Molten steel from the EAF is transferred by ladle to the AOD
furnace.  Although procedures vary somewhat, major alloy additives are
made in the AOD.  A mixture of argon-oxygen is blown into the molten
steel through tuyre pipes in the bottom or side of the furnace to oxidize
the carbon.  Nitrogen can also be added through these pipes if a nitrogen-
bearing grade of steel is desired.  After carbon oxidation is complete,
additional fluxes are added to remove sulfur and other undesirable
impurities from the molten metal.  Upon completion of the refining
process, excess slag  is removed and the remaining molten steel is cast
into ingots or electrodes for further processing.  The complete AOD
process usually takes about 90 minutes.
     During the carbon oxidizing process, emissions from an AOD furnace
are given off as copious dense black fumes.  When decarbonization is
complete, the emissions are much less, but are still quite significant.
The opacities of emissions from AOD's are similar to those from EAF's,
but mass emission data are not available.
     VIM and VAR furnaces are sealed refining furnaces that remelt materials
made by  the other furnaces for very special types of steel products.
Current  applied across the furnaces generates heat to the material to  be
remelted, and a vacuum to about 5 micrometers is drawn at the  same time
to degas  the molten  steel.  The steel  is  reformed into a new  ingot or
electrode, which may  be further processed.  As shown in  Figure 3-4,  the
electrode  is a  long  (10-15 feet)  cylindrical  (6-12 inches in  diameter)
piece  of  steel.  The  electrode  is used  in all the remelting furnaces,
                                    3-7

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 except the VIM furnace, which requires smaller than fist-size pieces for
 easier remelting.  Imperfections in castings made from this steel are
 eliminated by degasing.  Because these furnaces operate under a vacuum,
 no emissions are generated.
      ESR melting is a hyper-refining process in which ingots (electrodes)
 made from the EAF, VIM, and  VAR furnaces are remelted under a specially
 compounded molten slag.  Figure 3-4 is a schematic of the ESR furnace
 system.   Steels produced in  an ESR furnace have more uniform grain
 structures, fewer defects, and better mechanical  properties than  conventionally
 produced  steels.   Figure 3-5 shows one of the  features  of steel made
 from an  ESR furnace.   Current applied across the  furnace  generates heat
 to remelt the electrode.  New and  usually larger  ingots are made.
 There are no emissions  generated during this process.
 3.3  Emission Sources
      Most emissions occur during the  early "melting"  portion  of a  furnace
 cycle, although  significant  quantities  are also emitted during charging,
 tapping,  and  oxygen-blowing  operations.   Emissions of up  to  30 pounds of
 particulate matter per  ton of steel produced 4'5  are generally acknowledged.
 Information supplied by steel  manufacturers on the quantity of particulate
 matter collected  by control  devices suggests, however, that 30 pounds
 per  ton may actually be conservative    for production of carbon steel
 and  that  15 pounds per ton is  a  reasonable value  for alloy steels.
      Particulate matter emissions may also vary from cycle to cycle and
 from  batch to batch.  Contamination of the scrap steel with dust,  oil, or
volatile metals, for example,  increases emissions during charging.
An increase in electrical power to  a furnace increases emissions during
the scrap melting.  Variations in the quantity  of oxygen blown varies
emissions  during the blow.
                                   3-8

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r^
                                                 -ELECTRODE CLAMP
                                                 -ELECTRODE
                                                  COOLING WATER OUTLET

                                                  WATER COOLED MOULD

                                                  SLAG BATH
                                                  SOLIFIED SLAG LAYER
                                                  MELTING SUMP
                                                  SOLIDIFIED INGOT
                                                  COOLING WATER INLET
                                                  WATER COOLED BASE PLATE
   Figure 3-4.  Electroslag remelting process in which a solidified ingot is
   remelted and reformed into a superior product.
     Figure 3-5.  Slag in H13 bar before (left) and after (right) refining.
                               3-9

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3.4   References for Section 3.0

1.  Annual Statistical Report - American Iron and Steel Institute -
    1977. published by the American Iron and Steel  Institute, p. 53.

2.  Ibid, p. 72.

3.  World Steel Industry Data Handbook, Volume 1:33, Metal  Processinq -
    1978.

4.  Iron and Steel Industry, prepared by Environmental  Engineering,
    Incorporated for EPA, Contract Mo. CPA 70-142,  March 15, 1971,
    p. 8-6.

5.  Letter from George N. Stoumpas, American Iron and Steel  Institute,
    to Randy D. Seiffert, EPA, January 23, 1973.

6.  Background Information for Standards of Performance:  Electric Arc
    Furnaces in the Steel Industry, Volume 1, page  10,
    EPA 450/2-74-017a, October 1974.
                                  3-10

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4.0  STATUS OF EMISSION CONTROL TECHNOLOGY FOR ELECTRIC ARC FURNACES
     Emission control technology studied during the development of the
MSPS has not changed significantly since NSPS promulgation.  However,
insistence by some local control agencies today that no visible emissions
escape the EAF shop has encouraged the use of efficient systems and
caused some new concepts to be developed.  The more efficient systems
and new concepts are discussed in Section 4.1.1 through 4.1.6.  Other
EAF control systems are discussed in Sections 4.1.7 through 4.1.10.  The
major difference among all the systems is the method used to capture the
emissions from the furnaces.
4.1  CAPTURE SYSTEMS AND CONTROL DEVICES
4.1.1  Canopy Hoods in a Shop With a Sealed Roof
     The canopy hood (CH) system (Figure 4-1) consists of a canopy hood
suspended directly above each furnace connected to fans and ducts that
evacuate the air.  Since these hoods must not restrict movement of the
crane that transports  charges by raw materials to the furnaces, 30 to 40
feet of clear area is  provided  immediately above the furnaces.  Furnaces
charged through doors  in the side or fed through a chute do not require
much freeboard and hoods can be built nearer  the furnace.
     During  charging,  the fumes rising rapidly from the furnace are
often deflected from the hood by the crane and its charging bucket.
Cross drafts within  the building and large fluctuations in emissions
that sometimes exceed  the capacity  of the hood also cause  a great  deal
of emissions  to bypass the  hood.  Because the building  is  sealed,
fugitive emissions not captured  in  the  hood  accumulate  in  the upper  part
of the  building and  are gradually drawn  into designed  openings provided
in the  CH  ductwork.
                                  4-1

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     Canopy hoods are sometimes divided into sections and are  dampered
to maximize draft directly above the point of greatest emissions  during
charging, tapping, or slagging operations.
     After capture, the effluent is cleaned in the fabric filter.   The
hot furnace gas must be cooled by water sprays, radiant coolers,  dilution
air, or some combination of these devices to prevent rapid degradation
of the fabric.  Electrostatic precipitators and Venturi scrubbers  are
sometimes used.  If a precipitator is used, the gas is humidified  to
maximize the efficiency of the precipitator.  Only the Venturi scrubber
does not require any special treatment of the exhaust gas.
      FUGITIVE PICK-UP
        OPENINGS
^P> EXHAUST GAS
      CLEAN AIR
                          Figure 4-1. Canopy hood (CH) closed roof.
                                      4-2

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4.1.2   Direct Shell Evacuation in a Shop with Either Building Evacuation
       or Canopy Hoods and a Sealed Roof
      The direct shell evacuation system (DSE) unquestionably provides
the best control during meltdown and refining, and either building
evacuation (Figure 4-2) or canopy hoods (Figure 4-3) captures emissions
during charging and tapping.  The air flow to the canopy hoods or various
strategically located inlets to building evacuation ducts can be shifted
as ventilation requirements and emission of particulate from different
furnaces dictate.  Separate control devices can be used, or a single one
can serve both systems.
     This combination of equipment requires lower average air flow rates
than a canopy hood or building evacuation system alone, because fewer
emissions are released into the shop building and part of the heat load
is removed by the direct shell system.  However, the air flow must be
adequate to assure proper ventilation for an acceptable working environment.
Peak air flow rates are used for the building evacuation or canopy hood
system during charging and tapping when the DSE system is ineffectual.
At other times these peak flows can be reduced.
     The direct shell evacuation system cannot be used for all steels,
as explained in Section 4.1.8.
 4.1.3  Semi-enclosed Furnaces with Direct Shell Evacuation,  Canopy Hoods
      and Tapping Hoods
     A new concept  for containing air pollution from electric arc furnaces
was  developed in  1976 for a shop producing carbon steels in two furnaces
with 225 tons of  capacity each.  The furnaces are equipped with conventional
                                      4-3

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                                                                  CLEAN AIR

                                                                   EXHAUST GAS
     Figure 4-2. Direct shell evacuation - building evacuation (BE) system with closed roof.
FUGITIVE PICK-UP
   OPENINGS
                                                                  CLEAN AIR

                                                                   EXHAUST GAS
            Figure 4-3.  Direct shell evacuation - canopy hood (CH) with closed roof.

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DSE and CH systems.   The major innovations are:  (1) enclosures around
each furnace that act as chimneys to direct charging fumes up into the
canopy hoods (CH) and (2) hoods that capture emissions from the tapping
ladle and slag pot.   The shop roof is closed above the two furnaces.
Figure 4-4 shows these new concepts.
     The enclosure walls are designed to allow the crane to travel
between the hood and the furnace to position the charging bucket over
the furnace.  The charging enclosure is ample sized to allow the furnace
roof to swing over the tapping area, where it can capture emissions from
the pouring spout or any fumes that bypass the tapping hood.
     The most significant advance in technology embodied in this new
system is the use of a stationary hood that fits close over the tapping
ladle, as shown  in Figure 4-4.  The empty ladle is moved by crane to a
railcar, which is rolled under the  hood.  Molten steel is then poured
into the ladle through an opening in one  side  of the  hood.  This  type  of
hood cannot presently be used  on electric arc  furnaces because the  crane
cables interfere with placement  of  a hood.
     This system also has a  stationary hood over the  slag pot  through
which  the slag drops to  capture  the slag  emissions, even  though they  are
a  minor  source of emission  from  EAF's.
     The total air  flow design for  this system is  630,000 dry  standard
cubic  feet  per minute  (dscfm)  or 1600  dscfm per ton of  furnace capacity.
This  volume is about  the same  as that  used  for conventional  DSE-CH
systems  in  shops with  open  roofs.   This system combines  the  lower cost
                                   4-5

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                                                   OPERATING FLOOR
                            SLAG POT
Figure 4-4.  New system for capture of emissions from electric arc furnaces.
                            A_r,

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and energy requirements of a DSE-CH system with the higher capture
efficiency of systems with high air flow rates. According to the local
agency, this new system achieves better control than previous CH systems,
and no visible emissions are noted except during upsets.
4.1.4  Side Draft Hoods
     The side draft hood is another fume evacuation system available to
EAF's.  It is mounted on or near the furnace roof, as illustrated in
Figure 4-5.  The hood is designed with one side open so that the travel
of the electrodes is not restricted.  As fumes escape from electrode
holes, they are drawn into the open side of the hood.  Vanes for directing
air flow are provided on the ends of the finger ducts.  Hoods may also
be installed over the pouring spout and slag door to capture fumes
during melting.  Large exhaust volumes must be maintained for the side
draft to draw fumes laterally into the hood.   The larger exhaust flow
insures combustion of carbon monoxide and reduces downstream exhaust
temperatures.  The side draft hood is simpler  than a roof hood, places
less weight on the furnace and furnace tilting mechanism, and improves
access for maintenance of electrodes and cooling  glands.  To insure
effective capture of melting emissions, the furnace roof must be sealed
tightly to avoid the escape of fume.  This is  not a requirement of  roof
hoods, which enclose the entire  furnace top.
                                     4-7

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                                   1DD.
                            Figure 4-5. Side draft hood.
4.1.5   Furnace Enclosure
     Another new concept for containing air pollution from EAF's was
applied at a shop containing two 60-ton electric arc furnaces.   This
concept is a total furnace enclosure, which captures both primary and
fugitive emissions.  Openings were to be provided in the enclosure for
the charging, tapping, and slagging operations.  The system is a metal
shell shaped somewhat like a barn (Figure 4-6);  it completely encloses
the furnace and tapping area and can effectively capture emissions from
melting, charging, and tapping.   A large exhaust duct or hood near the
enclosure top removes charging and melting emissions (Figure 4-7) while
a separate, local hood contains  tapping fumes  (Figure 4-8).   Tapping
fumes are collected by diverting exhaust flow  from the enclosure to a
local hood adjacent to the ladle.   Sliding doors on the front,  back, and
top of the furnace allow entry of the charge bucket by conventional
crane and also provide for slagging, chemical  addition, and  oxygen
lancing (Figures 4-6 and 4-7).
                                   4-8

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 CHARGING
DOORS CLOSES
                                       SEGMENTED
                                       TOP DOOR CLOSED
                                       (AIR CURTAIN ON)
DIRTY GAS
T0 UNITS
                                                PERSONNEL
                                               DOOR CLOSED
                                              (EXCEPT TO .LANCE)
                                        • COOLING AND
                                         COMBUSTION AIR
                                         IN FROM BASEMENT
                                         (SLAGGING FUMES
                                         ALSO  CAPTURED)
                SECTION TO EAST
                 Figure 4-6. Furnace during melt and refine.

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                                                             CRANE SLOT
AIR  CURTAIN
 DISCHARGE
 OVERHEAD
CRANE  CABLES
INTAKEn
 DUCT
AIR  CURTAIN
 BLOWER
                                   CHARGE
                                   BUCKET
         VIEW TO SOUTH
   (DOORS SHOWN' OPEN FOR CLARITY)
           '(FRONT OF FURNACE)
                                           •ROOF SWUNG
                                           OFF FURNACE
                       SECTION TO NORTH


                             (BACK OF FURNACE)
                                                                          AIR
                                                                          CURTAIN
                                                                          INLET
                                                                          FLOW
                             Figure 4-7. Furnace being charged.

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CHARGING
 DOORS
CLOSED
•SEGMENTED
TOP DOOR' CLOSED
(AIR CURTAIN ON)
                 FURNACE
                 ROTATED
                 FOR TAP.
 wan
                                       DIRTY GAS
                                       TO UNITS
                                      ERSONNEL
                                     DOOR CLOSED
DOORS
CLOSED
                                                       N
             SECTION  TO EAST
                               TRANSFER  CAR-i  ' ""LADLE

                                     VIEW  TO  SOUTH

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MELT SHOP  BUiLDING  n DIRTY  GAS FROM
~	L-	  ] FURNACE  NO. 7
i

Fo
                                                      DIRTY GAS FROM
                                                      FURNACE  NO. 6
                                    VENTUR!
                                              LEAN-TO ROOF
                               COMMON  DUCT


                              DOWN-COMER
                        MANIFOLD  DUCT
                     STEAM  HYDRO '  UNIT
                      Figure 4-9. Gas cleaning system layout.

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STEAM LINE
   NOZZLE
MOUNT DUCT
-WATER INJECTOR LINE
   STEAM NOZZLE
              k
   -WATER  . A
    INJECTOR
                    MIXING-
                     TUBE
                  DRAIN WATER
                                      CYCLONES
                   Figure 4-10. Typical steam hydro unit.

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     During melting, doors are closed and fumes are exhausted from the
enclosure by a large rectangular exhaust duct located below the enclosure
top, above the furnace.  Between 75,000 and 90,000 afcm is withdrawn
from each enclosure by suction developed by the company's proprietary
Steam-Hydro scrubber, which cleans furnace exhaust (Figures 4-9 and 4-
10).  Slagging, chemical additions and oxygen lancing are conducted
through a third set of doors at the rear of the furnace.  The furnace is
tapped in a ladle, which is placed on a rail car by the overhead crane
and then rolled into position under the enclosure.  Tapping fumes are
collected by diverting the air flow from the main exhaust duct at the top
of  the enclose to  a  hood  adjacent  to  the  ladle.   Poth  furnaces and
enclosures  rest on  a  platform about 6.3 m  (20  ft)  above  the melt  shop
floor.   This  arrangement  provides  room  for  the  tapping  ladle  car  and
also  provides  air  flow from  underneath  the  furnaces  to  carry  fumes  to
the main exhaust duct.
      Durino charqina,  the  seamented too door  (Figure 4-6)  is  opened to
allow the crane to  enter  with the  charge  bucket (Figure  4-7)  and  the
feed  material  is discharged  to  the FAF.   The  unique  feature  about the
charging system is  that a  curtain  of  air  is blown  across the  open too of
the enclosure (Figure 4-7)  to push the  charging emissions  into the
intake duct leading to the scrubber.   This  was  designed to prevent  most
of  the charging emissions  from  escaping  the enclosure  and building.   The
company  reports  it has not, encountered  any  major oroblems in  using  the
enclosure.  According to  the company, about 90 percent or better of the
charging emissions are contained by  the enclosure; however,  recent FPA
observations  of  this facility report capture  efficiency of 50 to 90
percent, depending upon the operation.   There appear to be some  engineering

                                  4-14

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deficiencies in the design of the enclosure which could be corrected on
newer systems and improve the collection efficiency.  Another criticism
of the furnace enclosure is that only clean scrap can be melted because
flames from contaminating oil and organic matter from the hot furnace
reach the top of the enclosure.  The company indicated that trial runs
using dirty scrap showed additional enclosure height would be necessary
if dirty scrap were to be used routinely.  The fact that furnace enclosures
are being used in large BOPF shops suggests that this system offers a
comprehensive solution to the many problems of controlling process and
fugitive emissions from EAF's.
4.4.6  Brusa Closed Charging System
     The Brusa closed charging system, illustrated in Figure 4-11, has
been operating on a steel-making furnace in Italy for several years.
Exhaust gases from the hot furnace are vented through a rotary kiln or
drum.  Charge material is fed continuously down through the kiln and
into the furnace, where it is preheated by furnace gases to about 1000 C.
Volatile matter entrained in the charge is thus oxidized  and withdrawn
at the top of the kiln along with furnace exhaust gases.
     This system has the advantages of heat recovery and containment of
charging emissions in a fashion allowing for simple collection and
ducting to a control device.  This type of steel making is a continuous
process in that charge material is continuously added and the furnace is
tapped frequently.   There is a trend toward this type of operation in
steel-making furnaces, only one domestic foundry EAF is known to use
continuous charging.  The Brusa and other conceptual designs for closed
charging systems require small-sized scrap that will pass through the
enclosed conveyor system.
 . ~ .."  <„• • ->v                        4-15

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-pi
                                                                               ^

                                                   figure 4-11. Brusa charging and preheating system.

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 4.1.7  Canopy Hoods In Combination With Natural Ventilation Through
        Open Roof
      The canopy hoods (CH) are identical to those described previously;
 but, as shown in Figure 4-12, in some shops the roof monitors allow
 natural ventilation to augment ventilation resulting from the hood
 suction.  Unfortunately, they also allow any fume that bypasses the hoods to
 escape the building as visible emissions.   Air flows through canopy
 hoods in this type of system are quite high but less than required with
 a sealed roof.   Only fabric filters are known to be used with this
 system.
 4.1.8   Direct  Shell Evacuation System in  Combination With Natural Ventilation
      Through Open Roof)
      The direct shell  evacuation system, -shown in Figure 4-13,  withdraws
 all  potential emissions  directly from within the furnace before they can
 escape and be diluted  by the ventilation air.   A water-cooled air exhaust
 duct,  which extends  through the furnace roof,  is jointed near the furnace
 with a gap of one to several  inches  separating the  ends  of the  two duct
 sections.   This  separation permits  the furnace roof to be elevated and
 rotated aside to permit  top charging  and tilting of the  furnace for
 tapping and slagging.   (During  such  times,  DSE systems are ineffectual
 and  emissions rise directly through  the  roof of the shop.)  A few DSE
 systems  remain  in operation while the  furnace  is  tilted.   The incremental
 improvement  in  the capture  of emissions  is  very small, however,  because
 the  bulk of  tapping  and  slagging emissions  are  from the  ladle or  slag
 pot.   During operation,  the DSE system maintains  a  negative  pressure
within  the furnace.  As  a result, air  is drawn  into  the furnace around
                                  4-17

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     i.(SA   ^
MONITOR  f, 7    />
                                                    • CLEAN AIR

                                            iiS^p> EXHAUST GAS
      FURNACE
                O
                                                 FABRIC FILTER
      Figure 4-12. Canopy hood (CH) with open roof.
BUILDING
MONITOR
                                               CLEAN AIR

                                             > EXHAUST GAS
       &£ CHARGING
        V4   AND K
        WAPPiNGtfe
          EMISSIONS W
      FURNACE
 Figure 4-13. Direct shell evacuation (DSE) system with open roof.
                            4-18

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 the electrodes and through the gap into the exhaust duct.  This air not
 only cools the exhaust qas, but it permits combustion of the large
 amounts of carbon monoxide present.
      A well designed and operated DSE system is desirable not only
 because it can capture essentially all the dust generated during meltdown
 and refining (including emissions during the oxygen blow), but also
 because it inherently restricts the gas to be cleaned.  The DSE system
 provides maximum removal efficiency with minimal energy requirements.
 Unfortunately, as mentioned earlier, when the furnace is being charged
 or tapped, emissions billow to. the roof.  If the roof is open, the
 emissions exhaust directly to the atmosphere in a very visible plume.
      DSE cannot be used in the manufacture of all steels.   During the
 production of some alloys, a  second slagging operation is necessary.    A
 "reducing" slag is used to remove certain impurities  from the melt.  Air
 will  oxidize these slags and  render them ineffectual.   At such times,
 induction of air into  the furnace is  intolerable.   Although  it would
 appear  that the fan  on the DSE system could  be  turned  off when the
 "reducing slag" is in  the furnace,  the industry advances  a theory  that
 the configuration  of the furnace  roof that accommodates  the  DSE  system
 interferes  with the  required  temperature  homogeneity of  the melt.  The
 absence  of  refractory  where the discharge  duct  enters  the  roof  is  alleged
 to constitute a  surface  which  absorbs  more radiant  heat from  the melt
 than  it  returns, and results  in a cold spot  in  the  molten  steel.   Recently,
air curtains have  been used to prevent oxidizing air from entering a
furnace.  Air curtains also therefore  promote better temperature control
within the  furnace.   Some furnaces may not be able to use air curtains
because of  their specific operation and design.
                                   4-19

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4.1.9  Building Evacuation in Shop with Closed Roof
     With the building evacuation system (BE), the entire building is
used to capture dust from the furnaces.  As shown in Figure 4-14, hot
exhaust gases containing dust billow to the roof of the shop, where they
are drawn into ducts leading to a fabric filter.  Because the removal
capacity of the duct may be less than the furnace release rate, dust-
laden gas sometimes accumulates beneath the closed roof during periods
of high dust generation.  Since air cannot escape except through the
control device, the dust does not create an outside pollution problem.
     Since all ventilation air must exhaust through the control device,
operating costs have limited these systems to fabric filter collectors.
Gas  cooling systems have not been necessary because the ambient air
drawn  into the building mixes with and  cools  the  dust-laden gases.
      In  two aspects, BE systems  appear to  be  superior  to  DSE  systems.
They capture fumes  from the  charging  and tapping  operation,  and  operate
without  any visible emissions  from the building.   They also  have  no
effect on  "reducing slags"  and  are often the  choice of shops  that
produce  alloy  steels.
4.1.10  Direct Shell  Evacuation in  Shop with  Canopy Hoods with  Ooen  Roof
      This  combination  is  identical  to the  system described in Section
 4.1.2, with  one notable exception:   the open  roof monitors permit natural
 ventilation.   Because the open roof will  satisfy ventilation requirements,
 continuous air flow through the canopy hood is not required.  As a
 result, the hoods can be operated on demand to capture charging and
 tapping emissions.
                                  4-20

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                                                             CLEAN AIR

                                                             EXHAUST GAS
        Figure 4-14.  Building evacuation (BE) system with closed roof.
       BUILDING
       MONITOR
                                                            CLEAN AIR

                                                   SHMXHAUST0AS
Figure 4-15.  Direct shell evacuation (DSE)-canopy hood system with open roof.
                                 4-21

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     Fumes not captured by the hoods escape as a visible emission
through the open roof monitors.   Shops with many furnaces that have
staggered charging and tapping cycles will probably have visible emissions
through some portion of the roof monitors much of the time.
     Such losses can be minimized.  Louvers on the openings in the roof
can be automated to close during periods when the DSE is out of service,
to preclude emissions of fumes that bypass the canopy.  Fugitive dust
openings in the exhaust ductwork of the canopy hood could extract the
fugitive emissions that are trapped near the roof.  Such a system will
probably not eliminate all visible emissions, as some fume will still be
trapped in the roof when it is reopened for ventilation.  Also, in a
shop with many furnaces where many charges and taps occur, the louvers
may have to be closed most of the time.  The system would then approach
a BE system.
     Because the forced ventilation is supplemented by natural ventilation,
this combination system requires less forced air flow and less energy
than systems with a closed roof on the shop.
                                     4-22

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 4.2  Effectiveness of Various Control  Techniques
      Because direct assessment of these capture systems is difficult,
 few attempts are made to measure their efficiencies.   Efficiency "measurements'
 are usually visual estimates, which can vary considerably among observers.
 Estimates of emission rates for the various control  systems are, then,
 extremely dependent on the values and  estimates assumed.
      For NSPS development, theoretical  emission rate calculations were
 based on a canopy hood capture efficiency of 80 percent from an estimated
 range of 70 to 90 percent, depending upon several  variables.  2  These
 variables include the age of plant,  design of hood,  distance of hood to
 EAF,  shop configuration,  air currents  in  building, building design,  and
 rate  of  air flow to control  system.
      Because of the many  variables  involved,  the newer  technology
 requires  closed roofs  and  scavenger  ducts  to  capture  those  emissions
 escaping  the hoods.   At some  shops  full or  partial enclosure  of  the
 electric  arc furnace  is reported  to  capture 90  percent  of all  furnace
           3
 emissions.    Again,  this  is  a  visual observation rather than  a measurement,
 but the furnace  enclosure  configuration appears to improve  the reliability
of the visual observation  compared to canopy  hoods, which may  be  40 feet
or more above the source of emissions.   The semi-enclosed furnace system
also appears to provide better canopy hood capture efficiency because of
the ability to direct the emissions more effectively into the canopy
hoods.  Visual observations of this system estimate a hood capture
                                 4-23

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efficiency of 90 percent; but because the roof is sealed, all  of the
emissions should be captured and directed to a control  device.
     In conclusion, current control  technology such as  total furnace
enclosure, partial furnace enclosure with canopy hoods, canopy hoods
with fugitive dust pickup system, and sealed roof provides for improved
capture and control of all furnace emissions compared to the systems in
use at the time of promulgation of the NSPS.  Also, controls for tapping
and other fugitive emissions can be installed to further improve the
control of significant sources of EAF emissions.
4.3  CONTROL TECHNOLOGY APPLICABLE TO NSPS FOR EAF FURNACES
     Emission control technology to meet current NSPS  is directed to
controlling only  primary  emissions.  All the systems for the NSPS study
used a baghouse for the  control device.  The present NSPS provides  only
limited control of fugitive  emissions, meaning some of the  emissions
from tapping and  charging are not captured by the  canopy hoods.  The
visible emission  portion  of  the NSPS is  intended primarily  to  regulate
or  to  allow  for some  of  these emissions.  The NSPS is  generally  based on
direct shell evacuation  with canopy  hoods and an open  monitor  or canopy
hoods  with adjustable louvers  in  the monitor  that  can  be closed  to
contain  heavy  emissions  and opened  when  there are  no significant emissions.
 In  the NSPS  development, this  system was considered the  most  effective,
considering  costs.
 4.4  CONTROL TECHNOLOGY IN CURRENT USE ON NEW EAF  SHOPS
      The control  technology reviewed for this study revealed that  well-
 controlled EAF shops can use (1) direct shell evacuation and canopy
 hoods with a closed roof, (2)  canopy hoods with a fugitive dust pickup

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system and a closed roof,  (3) total furnace enclosure with an open roof
(however, the roof could be closed in future designs), and (4) semi-
enclosed furnace and canopy hoods with a fugitive dust pickup system and
a closed roof.  The reasons for the change from an open roof to a closed
roof are:  (1) the insistence of some local air pollution control agencies
on a more stringent visible emission limitation on the EAF shop than
required by the NSPS,  (2)  to meet EPA's off-set policies, or (3) to
prevent significant deterioration of the air quality in an area.  These
control systems also control essentially all emissions from the EAF
shop, including those  from charging, tapping, slagging, and teeming
operations and AOD furnaces and ladle fumes.
     The concern for the high cost attributed to handling large volumes
of gases from the evacuation of gases from a closed roof building apparently
has been overcome by using canopy hoods and adding a fugitive duct
system in the closed roof  monitor to collect fugitive emissions.  This
type of system allows  for  collecting and restraining the fugitive dust
emissions within the building and slowly drawing these emissions into
the control device as  the  process goes through its cycles.  Also, the
gas volume is reduced  in comparison to that involved in building evacuation,
because direct shell  evacuation or canopy hoods still collect the greatest
portion of the emissions, while the fugitive dust system is designed
only to pick up the small  balance of the emissions.
     There are not enough  data available from the testing of these
systems to indicate whether one or all of them could be considered "best
demonstrated control  technology."  The only criteria for comparison of
these systems during this  review was visible emissions.  Plant visits
and reports from air pollution control agencies indicate that these
systems are below the present NSPS for visible emissions.

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4.5  POTENTIAL NEW CONTROL TECHNOLOGY
     Control technology for future EAF shops can be designed as previously
discussed in Section 4.4 or additional control  measures can be added to
provide better control of the significant sources of fugitive emissions
during charging and tapping.  Tapping emissions, for instance, can be
controlled by using a tight-fitting swing-away hood over the ladle; or a
totally enclosed room can be used, with the ladle on a railcar.  The
industry practice has been to have the crane hold the ladle during
tapping; therefore, hoods and enclosures have not been used during the
tapping cycle.  This concept is slowly disappearing, however.
     Another potential technology, used at an EAF shop in Europe and at
one foundry in the United States, is  to use the gases from the EAF
furnace in a kiln to preheat scrap being continuously fed to the furnace.
This system permits heat energy recovery and reduces the volumes of
gases to be collected and treated.  The size of the scrap being fed must
be controlled. This system will also  need to be reviewed for other
negative aspects.
     Most of the  discussion  in this study is devoted to the capture of
the emissions.  Baghouses are still the most widely used control device;
only one proprietary  scrubber has  been  installed  since  1974.   The  design
of the  baghouse may  only  vary between having stacks or  open  tops to
discharge the  gases.   The  open-top,  pressure-type baghouse  is  not  easy
to source test and  enforcement  based  on compliance tests  is  difficult.
Methods for source  testing  this  type  of baghouse will  have to be  developed
 for  enforcement compliance requirements.
                                    4-26

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4.6  REFERENCES FOR SECTION *.Q

1.  Iron and Steel Engineer, July 1978.  Air Curtains on Electric
    Furnaces at Luken Steel Company.

2.  Background Information for Standards of Performance:  Electric
    Arc Furnaces in the Steel Industry.  U.S. Environmental
    Protection Agency, Research Triangle Park, N.C.  Publication No.
    EPA-450/2-74-017a.  October 1974.

3.  Blair and Martin, 1978.  EAF Fume Control at Lone Star Steel Company,
    Lone Star, Texas.
                                4-27

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5.0  CURRENT STANDARD FOR EAF'S IN STEEL INDUSTRY
     The MSPS regulates FAF's and their associated dust-handling equipment
that were planned, under construction, or being modified after
October 31, 1974.  An existing EAF is subject to the promulgated NSPS
if: (1) a physical or operational change in the existing facility causes
an increase in the emission rate to the atmosphere of any pollutant to
which the standards applies, or (2) if in the course of reconstruction
of the facility the fixed capital cost of the new components exceeds 50
percent of the fixed capital cost that would be required to construct a
comparable new facility that meets the NSPS.
5.1  EXEMPTIONS FROM NSPS
     Electric arc furnaces that process prereduced ore pellets are
exempt from the NSPS because the process was in the development stage at
the time of the NSPS investigation.  Also, emissions from this type of
furnace are reportedly generated at different rates and cycle times than
those from conventionally charged EAF's; therefore, the cycle for these
furnaces would be different.
     Electric arc furnaces used in foundries are not covered in this
MSPS, but will be covered under another NSPS regulation, specifically
for the foundry industry.  Specialty furnaces, such as, AOD, VAR, VIM,
CEM, and ESR furnaces, are exempt from this standard because they were
not entirely investigated during the development of the NSPS for conven-
tional EAF's.  These furnaces produce specialty steels, and the number
of such furnaces is relatively small compared to conventional EAF's.
Emission rates and process information for these types of furnaces were
not completely documented during MSPS development.
                                  5-1

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5.2  NSPS FOR PARTICULATE EMISSIONS
     Particulate matter is the EAF pollutant to be controlled by the
NSPS, as defined by 40 CFR 60, Subpart AA, dated October 21, 1974:
     "On and after the date on which the performance test required to be
conducted ... is completed, no owner or operator subject to the provi-
sions of this subpart shall caused to be discharged into the atmosphere
from an electric arc furnace any gases which:
     (1)  Exit from a control device and contain particulate matter in
          excess of 12 mg/dscm (0.0052 gr/dscf)."
     This standard was derived from test results from six well-controlled
plants of various capacities and control systems.  Vendor guarantees of
the control devices were also used in developing the NSPS.  Opacity
standards were developed to  limit visible emissions from the EAF  shops
during the various process steps.  Recent emission test data are  discussed
in Section 6.0.
     Performance tests to  verify compliance with particulate standards
for EAF's must be conducted  within 60 days after the plant  has  reached
its full capacity production  rate, but  not  later than 180 days  after the
initial  startup  of the facility  (40  CFR 60.8).   The EPA  reference methods
to be  used  in  connection with  EAF  testing  include:
        1.  Method  5  for  concentration of particulate matter and associated
            moisture  content.
        2.   Method  1  for  sample and velocity traverses.
        3.   Method  ?  for  volumetric flow rate.
        4.   Method 3  for  gas  analysis.
                                      5-2

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     Each performance test consists of three separate 4-hour runs, with
a minimum sample volume of at least 4.5 dscm (160 dscf). The arithmetic
mean of the three runs is the test result to which performance of record
used to determine compliance with the standard (40 CFR 60.8).  Performance
test requirements, including provision for exceptions and provision for
approval of alternative methods, are detailed in 40 CFR 60.8.
     Continuous monitoring for the measurement of opacity of emissions
from the control device(s) is required.
5.3  PROBLEMS WITH NSPS FOR VISIBLE EMISSIONS
     No air pollution control agency has reported any problem with the
present NSPS, except that EPA Region IV, (Atlanta, Ga.) expressed concern
about the EAF shop opacity requirement or definition.   Opacity source
tests conducted at one electric arc furnace shop showed that emissions
trapped in by a sealed-roof during the charging and tapping cycles
escaped when doors were open at each end of the shop, but produced no
violation of the NSPS.  Also, it was noted that overlapping charging and
tapping periods from heat to heat caused some confusion about the NSPS
shop opacity requirement.  This concern may be valid because the NSPS
opacity limits are:
     1.  Any gases which exit from a central device and exhibit
     three percent opacity or greater.
     2.  Any gases which exit from the shop and,  due solely to
     operations of any EAF(s), exhibit greater than zero percent shop
     opacity exceot (a) shop opacity greater than zero percent, but less
     20 percent, may occur during charging periods and (b) shop
                                5-3

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     opacity greater than zero percent, but less than 40 percent, may
     occur during tapping periods.
     Some review is needed to determine whether the opacity part of the
NSPS needs to be revised to cover problems such as those cited.  The
review should determine whether:
     1.  The definitions of charging and tapping periods need to be
         revised.
     2.  A NSPS for no visible emissions from an EAF may be viable
         because technology to control tapping and charging
         emissions is now available.
     3.  An EAF shop might be engineered to prevent emissions from
         drifting out the openings below the closed roof area.
     4.  This specific situation is a problem for enforcing NSPS for
         visible emissions
     Problems such as these are likely to emerge as agencies start more
compliance tests.
5.4  REFERENCE FOR SECTION 5.0
1.  Memorandum from Bruce Miller, EPA Region IV, to Drew Trenholm, EPA,
    OAQPS, ESED.   February 28, 1979.  Electric Arc Furnace Shop NSPS.
                                    5-4

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 6.0  CURRENT STATUS OF ELECTRIC ARC FURNACES IN STEEL INDUSTRY
 6.1  EMISSION DATA SINCE NSPS PROMULGATION
      There are five EAF's that are presently subject to NSPS regulations;
 however, one furnace has not started operation, three are still in the
 startup mode, and one was tested for visible emissions.   This last
 furnace met the NSPS, but the EAF shop did create the visible emission
 problem that concerned Region IV discussed in Section 5.3.
      Four other recently constructed EAF's were required by local  agencies
 to at least meet NSPS even though the EAF's were not subject to NSPS
 because their construction started before NSPS promulgation.  One shop
 with two partly enclosed furnaces using canopy hoods and a closed  roof
 was source tested for oarticulate and visible emissions.  The local
 agency has certified the system as meeting NSPS.   However, the  control
 system uses a pressure-type  baghouse,  and the testing was  conducted  by
 company personnel  with  local  agency observers.   The  testing  was  conducted
 by placing a  Hi-Vol  sampler  in  the various compartments  of the  baghouse.
 The results show  the  compartment  loading  ranged  from 0.0097  mg/dscm
 (0.0000042 gr/scf) to 0.08 mg/dscm (0.000035  gr/scf) during  12  tests  of
 4  to  5  hours  duration.  This  test  method  has  not been  approved  by  EPA.
 Another  EAF shop with a closed roof  submitted source test  data on  a AOD
 furnace  using a canooy hood.  The  control  device, a  baghouse with  stacks,
was source  tested using EPA Method 5.  The results showed  an average  of
        3             3
6.9 mg/m   (0.003 gr/ft ) for  the three tests.  One shop with a totally
enclosed furnace, using a scrubber as the control device,  reported a
range of 4.4 to 4.8 mg/dscm (0.0019 to 0.0021 gr/dscf) for three tests
using EPA Method 5.  The tests, conducted by the company, were observed
                                   6-1

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by State and FPA personnel.1   Two official  test reports were submitted
to EPA.1'2
     Although no other source tests have been conducted on any of the
EAF's that are required to meet "!SPS, Regions III and V have contracts
with 6CA Corporation and Acurex to study and source test about 20 steel
facilities, some of which have EAF's.  These  contracts should be completed
in late 1979.3
6.2 COMPARISON OF NEH CONTROL TECHNOLOGY AND CURRENT NSPS EMISSION
    CONTROL PERFORMANCES
     Table 6.1 shows emission reductions expected by the control technology
being used today compared to control technology for the current NSPS.
The table shows that the total reduction of particulates from EAF shops
would be about 50,340 tons per year  if the NSPS were revised to include
improved emission control technology.  Visible emissions would also  be
significantly reduced.
     Data from  industry  and  EPA  source tests  indicate  that  uncontrolled
particulate  emissions from the EAF  furnaces  average about 25.3 pounds
per  ton of  combined  carbon and alloy steel production.    Additionally,
alloy fugitive  emissions from  the  charging and tapping operation  average
about 1.5  pound  per  ton  of steel.   About 42,000  tons of particulate  is
generated  annually  from  the  charging and tapping operation, plus  353,000
tons per  year of uncontrolled  particulates  generated from the EAF furnaces
based.  These emission  data  are  based  on 27,882,000 tons of steel  production
 by EAF's  in 1977.
      The  control  systems considered for the  development of the current
 NSPS were the canopy hood and open roof or direct shell evacuation,
 canopy hood, and open roof.   These systems would reduce uncontrolled

                                  6-2

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                 Table 6.1  COMPARISON OF NEW CONTROL TECHNOLOGY AND  EXISTING  NSPS CONTROL TECHNOLOGY

                                    FOR ELECTRIC ARC FURNACES  IN STEEL  INDUSTRY
Emission
category
From
furnace


Charging and
tapping


Control
system
Canopy hood
Direct shell
evacuation/
canopy hood
Furnace
enclosures or
semi-enclosures
Canopy hood
Direct shell
evacuation/
canopy hood
Furnace
enclosures or
semi-enclosures
Removal efficiency, %
Current
NSPS and
open roof
87
87
Not
developed
80
80
Not
developed
New technology
and
closed roof
99
99
99
99
99
99
National particulates, tons/yr
Total
emitted
(uncontrolled)
353,000


42,000


Total
captured
Old New
307,110


33,600


349,470


41 ,580


Reduction
42,360


7,980


cr>
i
oo

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participate emissions from FAF furnaces by an average of about 87 percent,
collectively.  For emissions from the charging and tapping operation, it
was assumed that the canopy hoods would be 80 percent efficient.
     Presently available control systems are essentially the same as
those available for the original NSPS except that closed roofs with
fugitive pickup systems are being used.  New control technology includes
total or semi-enclosed furnaces and in most cases, closed roofs.  Even
though presently available systems should theoretically capture 100
percent of all emissions and should not allow any visible emissions, 99
percent particulate capture from an EAF shop was assumed because of
possible upsets, malfunctions, and other operating problems.
6.3  FUTURE GROWTH
     Because of the slow growth in the steel industry at this time and
because most new furnaces being planned for the next 4 years are replacements
for existing furnaces, the impact of emissions due to growth should  be
negligible during this period.  In fact, emissions could be reduced
through the superior control technology being aoplied to the new furnaces.
The exact number of new furnaces that will actually be constructed  in
the next 4 years cannot be determined because industry representatives
are reluctant  to state future  plans.
6.4  JUSTIFICATION TO  REVISE NSPS
     There is  probably sufficient justification  to  revise  the present
NSPS,  based  on the following considerations:
     1.   In  general,  control technology  better  than  that  needed to
comply with  the NSPS  is being  used  by  industry  today  for  new  and existing
EAF  shops.

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      2.   Although  data  on  NSPS  compliance for new EAF shops  are lacking,
 enough  data  may  be available  from existing well-controlled FAF shops to
 extrapolate  to future EAF  shops.   This  is especially true in the visible
 emission  portion of the f'SPS.
      3.   Fugitive  emission  control  technology (especially, for charging
 and  tapping  emissions)  has  been  developed.
      4.   AOD furnaces are  significant sources of  particulate and visible
 emissions, and should be considered  for  inclusion in the  NSPS even
 though  they  are  not really  EAF's.   However,  they  are an integral  part of
 an EAF  shop  operation,  and  frequently use the same or similar control
 system  as those  used by EAF furnaces.  This  inclusion would  probably
 require an additional definition  of  an affected facility  in  the  NSPS.
 6.5   REFERENCES  FOR  SECTION 6.0
 1.  Reinke, J.M.,  1976.   Letter dated November 1,  1976, to Mr. Michael
    Maillard.  Wayne County Department of Health,  Air Pollution  Control
    Division.  Detroit,  Michigan.
 2.  Adams, J.I.,  1978.   Letter dated September 20,  1978 to Mr. John  E.
    McGroqan, P.E.   Department of Environmental Resources, Bureau of Air
    Quality.   Wernersville, Pennsylvania.
3.  Region III and V Enforcement Divisions, 1979.    Personal  Communications.
4.  Particulate Emission Factors Applicable to the  Iron and  Steel Industry,
    Midwest Research Institute Draft Report - Table No. 8, April 5
    1979,  EPA Contract  No.  68-02-2609.
                                   6-5

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1. REPORT NO.
   EPA-450/3-70-033
4. TITLE ANf. SUBTITLE
   Review of Standards  of Performance for  Electric Arc
   Furnaces in Steel  Industry
9 PERFORMING ORGANIZATION NAME AND ADDRESS
   Office  of  Air  Quality Planning  and  Standards
   Environmental  Protection Agency
   Research Triangle park, North Carolina 27711
                                   TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing)
                              2.
                                                            3. RECIPIENT'S ACCESSION-NO.
                                                        5. REPORT DATE
                                                           October  1979
                                                        6. p;-.nr-r>HMiNG ORGANIZATION CODE
 . AUTHOR(S)
                                                            8. PERFORMING ORGANIZATION REPORT NO.
                                                            10. PROGRAM ELEMENT NO.
                                                         11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
DAA for Air  Quality Planning and Standards
Office of Air,  Noise, and Radiation
U.S. Environmental  Protection Agency
 Research Triannlp Park, N.O. 27711
                                                            13. TYPE OF REPORT AND PERIOD COVERED
                                                            14. SPONSORING AGENCY CODE
                                                                 EPA/200/04
15. SUPPLEMENTARY NOTES
16. ABSTRACT

         The purpose of  this study is to review  the current new  source performance
    standards  iNSPSy for electric arc furnaces  (EAF, in the steel  industry and to
    assess the need for  revision on the basis of developments that either have occurred
    or are expected to occur in the near future:  this document  contains background
    information, current status of emission  control technology for EAF s, and
    recommendations for  revision of the standard.
17.
a.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Air Pollution
Pollution Control
Standards of Performance
Electric Arc Furnaces
Particulates
13.
DISTRIBUTION STATEMENT
Unl imited
b. IDENTIFIERS/OPEN ENDED TERMS
Air Pollution Contr
19. SECURITY CLASS (Tlui Report)
Unclassified
20. SECURITY CLASS (This page)
Unclassified
c. COSATi Field/Group
3l 13 B
21. NO. OF PAGES
56
22. PRICE
EPA Form 2220-1 (9-73)

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