United States
                    Environmental Protection
                    Agency
Industrial Environmental
Research Laboratory
Research Triangle Park NC 27711
                    Research and Development
EPA-600/S7-84-011 Apr. 1984
SER&         Project Summary
                    Pilot Demonstration  of  Magnetic
                    Filtration  with  Continuous  Media
                    Regeneration
                    Carroll E. Ball and David W. Coy
                      A mobile pilot plant with a nominal
                    flow capacity of 3,060 mVhr (1,800
                    cf m) was designed and built to evaluate
                    the use of High  Gradient Magnetic
                    Filtration (HGMF) for participate emis-
                    sion control on  an electric arc furnace
                    (EAF). A 5-month program was con-
                    ducted at Georgetown Steel Corpora-
                    tion's plant in Georgetown, SC. to test
                    the performance of HGMF. A 500 hour
                    long-term test was scheduled and later
                    changed in order to perform additional
                    characterization studies.
                      The pilot plant collection efficiency
                    was less than expected for the stainless
                    steel wool matrix packed to a density of
                    1.5 percent by volume. The matrix was
                    then changed to  an expanded metal
                    packed to a density  of 3.5 percent by
                    volume, which resulted in much lower
                    pressure drops,  but even lower collec-
                    tion efficiencies. The expanded metal
                    matrix was then packed to a density of
                    6.0 percent  by volume which gave
                    higher collection efficiencies than the
                    steel wool and a slightly lower pressure
                    drop.
                      During the  field test,, there were no
                    significant problems with the HGMF
                    mobile pilot plant equipment.
                      The report  describes the design and
                    construction of  the continuous HGMF
                    mobile pilot plant, as well as some of
                    the background  work  in HGMF at
                    Research Triangle Institute (RTI).  The
                    field start-up  and performance charac-
                    terization of the mobile pilot plant are
                    discussed in detail. Experimental data
                    and data analysis are given, as well as an
                    economic evaluation and comparison
                    of HGMF with other particulate control
                    devices.
  This Project Summary was developed
by EPA's Industrial Environmental
Research Laboratory, Research Triangle
Park, NC, to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report  ordering
information at back).
Introduction
  Since the commercialization of High
Gradient Magnetic Filtration (HGMF) in
the clay industry 10 years ago, applica-
tions of magnetic separation of process
streams have been steadily increasing.
They include mineral beneficiation, coal
deashing, coal desulfurization, wastewa-
ter treatment, and  blood component
separation. The application of HGMF to
air pollution, however, is a recent
development. From 1975 to 1977,  RTI
conducted experiments, funded by  the
U.S.  Environmental Protection Agency
(EPA), in applying HGMF to air pollution
control. Magnetic separation was tested
in the laboratory on several dusts from
the iron and steel  industry. There were
promising results from the following iron
and steel industry sources: the  basic
oxygen furnace (BOF), electric arc
furnaces (EAF), the blast furnace (BF),  the
open hearth furnace, the scarf ing machine,
and the sinter machine.
  An earlier pilot plant was designed and
built by RTI and tested on a Pennsylvania
sintering plant. Overall efficiency data
were low for these tests, however, due to
the low specific  magnetization of  the
sinter plant dust. It was then decided to
design and build a pilot plant with
continuous media regeneration and test

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it on a dust with higher specific magneti-
zation; e.g., BOF or EAF dust.
  In June 1981, the pilot plant was
moved to Georgetown, SC, and connected
to a slipstream from the exhaust of three
EAFs, just upstream of a baghouse. After
start-up and debugging, tests were started,
to give  results on the effects of filter
density, applied magnetic field, and gas
velocity on overall and fractional collec-
tion efficiency. A  500-hour long-term
test,  planned at  optimum operating
conditions, was  later cancelled due to
lower-than-expected  collection efficien-
cies. It was decided to use the remaining
time for additional  performance charac-
terization tests with changes in the pilot
plant recycle stream. Total mass  and
fractional collection efficiency tests were
conducted,  and samples of  the dust
entering,  exiting,  and captured by the
pilot plant were collected for magnetic
and chemical analyses.
  Field test results were used for techni-
cal  and economic  assessments  of the
application of HGMF to  EAFs, and to
compare HGMF to other types of pollution
control devices.

Background Development

Basic Concept
  The fundamental concept of HGMF is
the interaction between paramagnetic or
ferromagnetic particles and ferromag-
netic fibers,  in the presence of an applied
background  magnetic field. The applied
magnetic field induces a magnetic dipole
in the particle and magnetizes the wire.
This creates a convergence of the field
near the  wire resulting  in a net force
bei ng applied to the particle. The magnetic
force, competing with the viscous,
inertia), and gravitational forces, causes
the particle to be attracted to the wire and
held there  until  the applied field  is
removed.
  The HGMF consists of several cassettes
packed  with ferromagnetic fibers (e.g.,
stainless  steel wool or expanded metal)
which are moved into a magnetic field as
the particle-laden gas is passed through.
The particle-laden gas is cleansed as the
particles are attracted to and held by the
fibers. When the  matrix is loaded, the
cassette is  moved out of the magnetic
field and  the particles are flushed from
the fibers.

HGMF Development and
Applications
  Experiments in HGMF, except  for the
EPA-sponsored development  begun  in
 1975, have been most concerned with the
magnetic separation of particles  in  a
slurry.  Several excellent reviews of the
process and its  chronological  develop-
ment have been published.
  The  most extensive  development of
HGMF  has been within the last decade in
the clay industry. Here, HGMF is used to
separate small paramagnetic color bodies
from kaolin clay.  The successful demon-
stration of this process in the clay industry
has sparked investigations of HGMF for
many applications.


Detailed Design and
Construction  of the HGMF
Mobile Pilot Plant
  The mobile pilot plant is a continuous
HGMF  system housed in a 12.8 m (42 ft)
freight  van. The system is designed for a
nominal flow capacity  of 3,060  mVhr
(1,800cfm). Figure 1 is a schematic of the
continuous HGMF system.
  The  dirty gas  enters the pilot plant
through a 0.25 m ID stainless  steel pipe
(10 in. schedule 5). The gas passes by test
ports (through which  samples can be
drawn to determine inlet dust concentra-
tion, chemical composition, and size dis-
tribution) and  then is directed  to the
HGMF  device.  The magnetic  filter  is a
Sala-HGMS® Carousel Model 120-05-
00(Sala Magnetics, Inc., Cambridge, MA)
incorporating  a  magnet  head  and a
cleaning station mounted 180° apart on a
rotating carousel. The magnet coils are
split into a saddle configuration to allow
the carousel to be rotated through the
magnetized zone by a variable speed
drive. The carousel contains 48 removable
cassettes which can be loaded with filter
material to a depth of 0.15 m (5.8 in.). The
magnet head encloses an active face area
of 0.085 m2 (133 in.2) in the direction of
fluid flow. The magnet  head is designed
to provide an applied field ofO.Oto5.OkG.
In the range of gas velocities tested, 2 to
10 m/s, the gas residence time in the
filter varied from 0.015 to 0.075 s.
  After passing through the magnet, the
gas passes by another set of  test ports
and exits the pilot plant. After leaving the
pilot plant, the gas is directed through an
orifice, for velocity (flow rate) determina-
tion, and  an  induced  draft blower and
then is exhausted  to  the  atmosphere
through an 8 m (26 ft) high stack.
  After the filter material  has  passed
through the magnetized zone and collected
the dust particles, it passes through the
cleaning station. The filter is cleaned by
backflushing with compressed air.
  The  agglomerated dust that  is cleaned
from the filter material with the cleaning
air pulse is sent to a  cyclone. Exhaust
from the top of the cyclone is recycled into
the dirty gas stream. Dust can be removed
from  the cyclone (through a double-
sealed valve) while the power plant is
operating.
  The induced draft blower which moves
the gas through the pilot plant is rated at
3,060  mVhr at a suction pressure of
-13.7 kPa (-55 in. HaO) and a temperature
of 250°C. The system is designed to allow
continuous operation at temperatures of
up to 200°C. All interior and exterior pipe
is insulated with jacketed fiberglass.
  The  utility requirements of the  pilot
plant are electricity and water. The main
power panel has 400 A service of 440
VAC input. The  total connected load is
300 A. The major equipment operates off
440 VAC, and a transformer is provided to
step down to 240 and  120 VAC. Water
consumption is about 2.3 mVhr (10 gpm)
for  magnet  cooling,  compressor after-
cooler, and occasional use of the laboratory
sink.

Field Operations

Description of the Electric Arc
Furnace at Georgetown, SC
  The dust source is an EAF shop utilizing
three arc furnaces operating continuously
in a  staggered batch operation.  The
Georgetown Steel raw steel production
facilities consist of three 68 Mg (75 ton)
per cycle DeMag electric arc furnaces.
The charge  to the furnaces consists of
scrap  and prereduced  iron pellets: the
scrap is obtained primarily from external
sources  (about  5 to  10 percent is
reclaimed scrap), and prereduced pellets
are produced on-site from South American
iron ores. Other materials added to the
furnaces  during the production cycle
include limestone, coke, ferromanganese,
and ferrosilicon.
  Gas from the furnaces is cleaned by
a positive-pressure baghouse supplied
by American Air Filter. A slipstream of
gas  was taken  from the  duct.  Gas
stream conditions  at the  extraction
point  are:
Pressure          -1.7kPa (-7 in. H2O)
Temperature      71° C (160° F)
Velocity           17 m/s [55.65  ft/s)
 Reynolds No.
4.1 x10°
Performance Characterization
  The program was designed to test both
the effects of four variable parameters
(applied field, gas velocity, filter type, and
filter packing  density) on collection
efficiency, and the reliability  of the
equipment during long-term operation.
  Selecting optimum operating conditions
was the goal  of this phase of the testing,

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                                                                                   V
                                                                             Cleaning Air Storage
                                          Flush Station
Figure 1.  Continuous HGMF system.
based on  statistical  analysis of the
performance data obtained under varied
operating conditions. Performance under
each set of conditions was to be measured
by sampling the HGMF inlet  and outlet
particulate  concentrations. Overall effi-
ciency would be determined on a mass
basis, and fractional efficiency would be
determined by measuring inlet and outlet
particle  size distribution. Periodically
during the characterization, bulk samples
of the particulate  were to be obtained
from the  inlet, outlet, and cyclone catch in
order to determine the chemical composi-
tion  and its effect on performance and
vice versa.
  The  applied magnetic fields were
varied between 0 and 5 kG for each of
three test series. Gas velocities through
the filter were varied between 2 and 10
m/s.
  The initial filter medium was American
Iron and Steel Institute Type 430 medium
grade stainless steel wool packed  to a
density of 0.015 (1.5 percent by volume)
and came packed  in the carousel  from
Sala  Magnetics.  The average fiber
diameter of this material is 120 Aim.
  The second and third test series were
run with expanded metal matrices (layers
of wide  mesh screen separated  by
spacers). The expanded metal matrix can
be packed with all of the fibers perpendi-
cular to the  magnetic field and in the
optimum position for particle capture. It
had been hoped that this would create a
higher collection efficiency for the same
pressure drop as was  attained with a
stainless steel wool matrix.
  The average fiber diameter of the
expanded metal matrix is 300 /urn. In the
second test series,  the  approximate
packing density of the expanded metal
matrix was calculated to be 0.035. In the
third test series, the packing density was
calculated as O.O6.
  Multiple  linear (slope-intercept form)
regression techniques were  used to
analyze the overall mass efficiency data.
The groups of data for each matrix type
and  packing  density  were obtained in
sequence,  rather than randomly, owing
to the difficulty of changing the  carousef
cassettes.   Also because of this factor,
statistical  analyses  were  performed on
the data grouped by  packing type  and
packing density. Using  statistical tech-
niques, an  exponential model was found
to produce the best data fit.
  The comparative  performance of the
filter system for  both matricies  and
packing densities is shown in Figure 2.
The  performance  data are plotted as
penetration (1 -efficiency) versus regres-
sion function. The line through each data
set is the regression curve for that set.
The regression coefficients a, b, and c for
each  set of data are given  in Table 1.
To compare the performance one  must
examine the penetration at low values of
the regression function for each data set.
Looking at the functional relation of each
variable in  the regression function, it is
expected that best performance would be
measured for  low  regression function
values; i.e., low inlet mass, low velocity,
and high field strength. Differing absolute
values of the regression function occur
between sets because  of the different
regression coefficients for each data set.
At low values of the regression function,
poorest performance was measured for
expanded metal at  3.5 percent packing
density, with  clearly  best performance
from expanded metal at 6 percent packing
density.
  Table 2 presents the predicted penetra-
tion based on the model and coefficients
in Table 1 for both matrices and packing
densities at fixed system  operating
conditions. Predicted penetrations are
lower for expanded metal at 6 percent
packing density and the observed pressure
drop was also lower for this  matrix than
for steel wool. Pressure drop was signifi-
cantly lower  for expanded metal at 3.5

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   700
c
.0
g
    10
                                          Steel Wool
                                            0.015
               Expanded
                 Metal
                 0.035
            B
                                                        Expanded
                                                          Metal
                                                          0.06
       - O
Figure 2.
Table 1.

Model:
                                10                               100

           Regression Function  _   [Inlet Mass"] [Velocityf
               Inlet Mass        [field Strength]0 [Inlet Mass]

  Georgetown Steel HGMF test--penetration vs. regression function [all matrices and
  packing densities].


Regression Coefficients for Each Filter Matrix and Packing Density

      = Intercept x 
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 Table 2.   Predicted Filter Performance for Each Filter Matrix and Packing Density

Model: Outlet mass=Intercept x"nlet massf fl^W"
                             (Field Strength/1

                                Matrix and packing density
Operating
conditions*
0.1 kG
7 m/s
Steel wool
0.015
Penetration %
26.2
A/*
38.1
Expanded metal
0.035
Penetration %
22.5
A/""
25.4
Expanded metal
0.06
Penetration %
15.2
APb
30.5
2.5 kG
  7 m/s

5.0 kG
  7 m/s
9.5


7.6
38.1


38.1
 14.4


 13.1
                                                    25.4


                                                    25.4
7.3


6.2
30.5


30.5
" Inlet concentration -1.0 g/m3.
" Actual pilot plant AP, cm H-f>.
    100
     10
|
I
    0.1
            O i Steel wool matrix 0.015 packing density

            D'' Expanded metal matrix 0.035 packing density

            A Expanded metal matrix O.O6 packing density
                  7.0 m/s Velocity

                  2.5 kG Field strength
       0.1
                                                     10
                                                                           100
                                 Particle Diameter, fim
Figure 3.    Georgetown Steel HGMF test-penetration vs. particle size.
ces deserve further  study toward addi-
tional optimization.
  For the given conditions of applied field,
velocity (residence time),  and inlet
concentrations, the best overall efficien-
cies achieved were in the range of 94 to
96 percent with outlet concentrations in
the  range of 20 to 70 mg/m3. The
efficiency  levels  are  much improved
over those achieved in the previous pilot
plant work on sinter plant emissions. The
performance levels, however, are not
competitive  with conventional high
efficiency control devices applied to
 electric arc furnaces. The New Source
 Performance Standard (NSPS) for electric
 arc furnaces limits particulate emissions
 to 12 mg/dsm3. The HGMF outlet concen-
 trations in these tests were 2 to 6 times
 the  required level. State standards for
 existing sources vary considerably; e.g.,
 Pennsylvania equivalent to 18 mg/dsm3,
 and Michigan equivalent to 130 mg/dsm3.
 On  a performance basis, HGMF  might
 have some limited retrofit potential.
  The fractional penetration data shows
 that HGMF  was not  as effective on
 particles smaller than 1 fjm in diameter as
 on those larger. In terms of fractional
 particle size penetration, it is  not evident
 that any significant qualitative differences
 exist between  HGMF and conventional
 control devices.
  The magnetic analyses data reveal that
 HGMF did not remove all of the magnetic
 material.  The magnetic material  pene-
 trating the collector may do so because of
 insufficient residence time or reentrain-
 ment. The chemical analyses  data reveal
 a significant amount of iron  penetrated
 the  filter,  especially in the small particle
 size (below 1 /urn) fraction. Penetration of
 the  iron  may   be  due  to insufficient
 residence time and reentrainment.
 However, a recent  report,  indicating
 some iron in electric  arc furnace dust to
 be  present in  a "non-magnetic" form
 (probably meaning not ferromagnetic),
 suggests a third mechanism for penetra-
 tion. The HGMF's sensitivity to chemical
 composition of particles and their resulting
 magnetic  susceptability is analagous to
 the  effects of chemical composition on
 particle resistivity and electrostatic pre-
 cipitator performance.
  An  alternative  use  for HGMF (not
 explored in this study) is to separate non-
 magnetic  components of waste EAF dust
 from magnetic  components;  i.e. ferrous
 and  non-ferrous. At present, EAF dust is
 classified  as hazardous waste as a result
 of heavy metals contamination. Separa-
 tion  of the ferrous portion with minor
 contamination  by zinc might permit its
 recycle to steel-making, reducing the
 residue for  disposal. With  sufficient
 concentration of zinc,  the non-ferrous
 portion might be sold to zinc refiners. The
 association of  iron  and zinc  in non-
 magnetic  particles identified in the study
 discussed above  suggests that this
 potential  application of  HGMF  needs
 further study to determine the degree of
 separation achievable.


 Economics
  Approximate costs have been developed
for four different options for  particulate

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emission control of electric arc furnace
(EAF) dust. The accuracy of these costs,
shown in Table 3, corresponds roughly to
that of a study grade  estimate (± 30
percent). Although a best estimate  is
presented for both capital and  annual
expenses, remember  that  the absolute
costs of the four options may depend on
special  process  details, plant location,
and material  of construction.  Considera-
tion of these details was not within the
scope of the estimate. However, the
estimates were made for the following
common base case:
Volumetric flow rate  8,500 mVmin @ 66°C
Inlet dust loading            1,050mg/sm3
Outlet dust concentration       12 mg/sm3
Annual operation              8,500 hr/yr
  For purposes of the economic compari-
sons, it was assumed that HGMF per-
formance could attain the outlet concen-
tration needed to  comply with the EAF
NSPS (12 mg/dsm3).
  In  addition, the following system
parameters specific to each option were
specified based on engineering judgment:
                HGMF
                     Superficial face velocity
                      7 m/s 5 m/s 2 m/s
Flow velocity
APHGMF-cm H2O
Total fan static AP, design
operating

                 ESP
Migration velocity
Specific collection area
                      33.0   178   25
            63.5
            50.8
50.8
38.1
38.1
25.4
                  4.6 cm/s
              100 mVmVs
APEsp                     2.5 cm H20
Total fan static AP, design   5.9 cm H20
        operating           3.9 cm H2O

             Fabric Filter
Air/cloth                     1.0 cm/s
APFF                     20.3 cm HZ0
Total fan static AP, design 50.8 cm HZO
        operating         38.1 cm HZO

           Venturi Scrubber
L/G                    93 I/1,000m3
APvs                      152 cm H2O
Total fan static AP, design  203 cm H20
        operating          191 cm H20
Water recycle ratio                0.9
  The scope of the cost estimates includes
flange to flange costs from the confluence
of the paniculate collection hoods (e.g.,
shell and canopy) to the discharge of the
clean air from the control device. For the
venturi scrubber, costs of sludge treatment
equipment  are  also  included. It  is
assumed that utilities are available at the
plant site at the following rates:
  Electricity              $0.05/kWh
  Plant  water             $0.066/kl
  Cooling water           $0.026/kl
  Compressed air        $0.706/km3


Capital Costs
  The total costs were calculated using
a  modified Lang  method;  i.e., applying
factors to the purchased equipment costs
to account for direct and indirect installa-
tion costs.
 Tables.
Costs of Various Control Options for EAF Paniculate Emission
                          $/m3/s
                 Total capital costs
                            Total annual/zed costs
                            10 yr*	20 yr"
                                Direct operating costs
HGMFC
2 m/s
5 m/s
7 m/s
ESP
FF
VS
31.31
20.99
14.16
11.94"
11.11
17.58
7.06
5.21
4.07
3.43
3.64
8.11
5.64
4.26
3.43
2.89
3.14
7.31
0.71
0.95
1.20
1.01
1.09
4.55
 a Total annual costs are computed for both 10-and 20-year capital recovery periods. The capital
  recovery factor for 10 years is 0.16275 and for 20 years is 0.11746.
 b Direct operating costs include operation and maintenance labor, supervisory overhead, and
  utility costs. They do not include capital recovery charges or taxes, insurance, and administrative
  charges (taxes, insurance, and administration are computed at 4 percent or the total capital
  costs).
 c Values given for three separate face velocities.
 " Capital costs for the ESP were calculated in four ways:
  (1) Ratio from EPRI research project 834-1, using empirical
     factors                                            Cost = $ 11.50/am3/s
  (2) Itemized major equipment and cost factors              Cost=  10.47/am3/s
  (3) Escalate from Environmental Science and Technology, Vol. 12,
     No. 13                                            Cost =  13.11/am3/s
  (4) Ratio from EPRI research project 834.1, using "0.6 rule"  Cost =  13.13/am3/s
  A substantial amount of engineering
judgment is  used in formulating these
factors. However, the relative order of
these factors for the ESP, VS, and FF is
consistent with other data. These factors
reflect the expense  necessary to install
and put  into  operation each  control
option.  The  ratio between installation
costs and purchased equipment costs for
HGMF was judged to be lower than for
either the ESP or FF.
  Table 3 shows that HGMF is more capital
intensive than  either  the ESP or  FF.
Looking  at the annualized  costs,  the
venturi scrubber is not  competitive with
any of the other three options at the given
conditions. Direct operating costs, which
do not include the cost of capital over the
life of the unit, are slightly higher for the
HGMF at 7 m/s than for either the ESP or
FF. However, the difference  in both capital
and direct operating costs among  the
HGMF, ESP, and  FF is  well within  the
probable  error of the  estimate (±30
percent).
  It is important to note that tax consider-
ations are not part of this  estimate.
Investment tax credits and  other  tax
incentives could offset some of  the
initially higher  HGMF  capital costs by
reducing  the  total annualized  costs of
Table 3.


Conclusions
  The following conclusions were drawn
from  the  field  operation of the HGMF
mobile pilot plant:
  1. While no long-term continuous 500
     -hour test was  performed, the
     continuous cleaning system for the
     filter was capable of maintaining a
     stable pressure drop  through the
     matrix at  each  of the  velocity
     conditions during  1- to  2-week
     periods of performance characteri-
     zation.
  2. Test  series were performed on two
     types of matrices at three levels of
     matrix packing density. The best
     overall performance of the HGMF
     unit was achieved with the expanded
     metal matrix at a packing density of
     6 percent. The highest  efficiency
     level  achieved  was 96.4 percent;
     five  of nine  tests  (excluding zero
     applied magnetic field  tests) were in
     the range of 93.9 to 96.4 percent.
  3. Pressure  drop through  the filter
     matrices varied directly with the
     superficial gas velocity through  the
     filter, approximately as the square of
     the velocity. In the velocity range of
     4 to  8  m/s, the  expanded metal
     matrix  at  6 percent had lower

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   pressure drops (10 to 46 cm H2O)
   than the steel wool matrix (16 to 50
   cm  H2O). Given the  better overall
   performance (both efficiency and
   pressure drop) with the expanded
   metal at 6 percent packing density, it
   was the preferred filter matrix.
4. Fractional penetration curves show
   performance of the  HGMF to be
   relatively poor (85 percent efficiency
   or less) in the particle size range
   below 1 /urn.
5. Elemental chemical analyses show
   iron removal efficiencies are higher
   than overall mass efficiencies as
   determined from thimble dust sam-
   ples. However, elemental analyses
   of cascade impactor samples show
   the iron penetration to be as much
   as 6  percent when  overall  mass
   penetration is 9 percent. Potential
   explanations for inadequate capture
   of iron-bearing particles include:
  a. Magnetic forces acting on the fine
    particles are not sufficient to effect
    capture as the gas passes through
    the filter due to  insufficient resi-
    dence time.
  b. Some of the iron occurs in complex
    compounds with zinc that is  not
    sufficiently magnetic to be captured;
    this is supported by work done at
    Lehigh University on waste dusts
    from electric arc furnaces.
  c. Reentrainment.
6. The overall penetration  of electric
   arc furnace dust through HGMF
   measured in this program  must be
   reduced by  a factor of  2 or 6 to
   compete with the performance of
   conventional particulate control
   devices applied to  new sources.
   Standards  for existing sources in
   some states might permit the retrofit
   of an HGMF.
7. Assuming HGMF performance can
   reach a competitive level in  the
   configuration and operating  mode
   tested  in this program (e.g.,  99
   percent efficiency),  comparative
   annualized costs  for  HGMF, fabric
   filters, ESPs, and venturi scrubbers
   show that  HGMF  can compete
   economically with venturi scrubbers,
   but is more  expensive than fabric
   filters  and ESPs.  Since, to achieve
   that level of performance on EAF
   dust,  it would be  necessary to
   reduce the  gas  velocity and/or
   increase  filter length,  it will  be
   difficult for HGMF to  compete as a
   control device for EAFs,
Carroll E.Bali and David W. Coy are with the Research Triangle Institute, Research
  Triangle Park, NC 27709.
William B. Kuykendal is the EPA Project Officer (see below).
The complete report, entitled "Pilot Demonstration of Magnetic Filtration with
  Continuous Media Regeneration," (Order No. PB 84-153 204; Cost: $14.50,
  subject to change) will be available only from:
       National Technical Information Service
       5285 Port Royal Road
       Springfield, MA 22161
        Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
       Industrial Environmental Research Laboratory
       U.S. Environmental Protection Agency
       Research Triangle Park, NC 27711

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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300

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                                                                                            U.S. GOVERNMENT PRINTING OFFICE: 1964-756-102/925

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