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					Allied Environmental Technologies, Inc.
MULTI-STAGE COLLECTOR
        (MSC™)
     DEVELOPMENT


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     Allied Environmental Technologies, Inc. - MSC™ Development
    Introduction

Multi-Stage Collector
l   The MSC™ offers a new method and design
    for collecting dust or fume from industrial
    gases that is virtually independent of
    electrical resistivity
l   This design will be particularly advantages
    when the material to be collected consists of
    a sub-micron dust or fume



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             Allied Environmental Technologies, Inc. - MSC™ Development
Evolution of
Electrostatic
Precipitation


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 Allied Environmental Technologies, Inc. - MSC™ Development
    Evolution of Electrostatic Precipitation


l   A typical electrostatic precipitator
    incorporates two zones:
    l   the CHARGING zone, where the dust or
        aerosol particles are being charged, and
    l   the COLLECTING zone, where the
        charged particles are being separated
        and transferred from the gas stream to a
        collecting electrode


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               Allied Environmental Technologies, Inc. - MSC™ Development
    Evolution of Electrostatic Precipitation



l   The arrangement of these zones led to
    two typical precipitator design
    concepts:
    §   an electrostatic precipitator where both
        zones are combined in a Single-Stage,
        and
    §   a Two-Stage design where these zones
        are separated

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               Allied Environmental Technologies, Inc. - MSC™ Development
         Evolution of Electrostatic Precipitation


                                                                                   Two-Stage Precipitator
                                                                                   Two-Stage Precipitator




   Single-Stage
Single-Stage
       Precipitator
    Precipitator




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                      Allied Environmental Technologies, Inc. - MSC™ Development
         Evolution of Electrostatic Precipitation

•   Here is different design for a
    Two-Stage ESP
•   It utilizes the unique electrode
    design that provides for
    separate zones for aerosol
    particles charging and
    collection in a compact
    design
•   According to this design, the
    dust collecting assembly
    comprises of a system of bi-                      The spacing between the surfaces
    polar charged surfaces, which                     in the charging and collecting
    are engineered in such a way                      zones is different, wider in the
    that they provide alternate                       charging or corona generating
    separate zones for high-                          zones and narrow in the collecting
    tension non-uniform and                           ones where a uniform high-tension
    uniform electrostatic fields                      electric field is being required
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                     Allied Environmental Technologies, Inc. - MSC™ Development
Barrier Filtration



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   Allied Environmental Technologies, Inc. - MSC™ Development
      Barrier Filtration

l   Fabric filters are a popular means of
    separating particles from a gas stream
    because of their relatively high efficiency and
    applicability to many situations
l   Fabric filters can be made of either woven or
    felted fabrics and may be in the form of
    sheets, cartridges, or bags, with a number of
    the individual fabric filter units housed
    together in a group
l   Bags are by far the most common type of
    fabric filters, hence the use of the term
    "baghouses" to describe fabric filters in
    general


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            Allied Environmental Technologies, Inc. - MSC™ Development
      Barrier Filtration

l   Ceramic filters have become available that can be
    used for high temperature filtration applications
l   Ceramic material is formed into stiff cylindrical
    filter elements, called "candles"
l   The open ends of the tubes are mounted either
    vertically or horizontally on a tubesheet, as with
    fabric bags
l   Tubes are generally cleaned by pulse jets
l   During the last years, porous metal media had
    gained importance in the field of gas dedusting or
    product recuperation in gas streams
l   The two most widely used types of porous metal
    media are sintered metal fiber and sintered metal
    powder

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            Allied Environmental Technologies, Inc. - MSC™ Development
      Barrier Filtration

l   The major particle collection mechanisms of fabric
    filters are inertial impaction, diffusion from
    Brownian motion, and interception
l   Collection may also occur due to gravitational
    sedimentation
l   Electrostatic attraction could play a significant part,
    for example in the Electrostatically Augmented or
    Enhanced and Hybrid technologies
l   The fabric is responsible for some filtration, but
    more significantly it acts as support for the dust
    layer
l   The layer of dust, also known as a filter cake, is a
    highly efficient filter, even for submicron particles

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             Allied Environmental Technologies, Inc. - MSC™ Development
Barrier Filtration

   Particle Collection Mechanisms in
               Barrier Filters




                                                                   EPA- 450/3-81-005a, NTIS PB83-127498




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      Allied Environmental Technologies, Inc. - MSC™ Development
  Hybrid Particulate
Collection Technology



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     Allied Environmental Technologies, Inc. - MSC™ Development
    Hybrid Particulate Control Technology


l   Electrically-charged particles have
    been found to form highly porous dust
    layers in fabric filters
l   Efforts to increase barrier filters
    efficiency without a corresponding
    increase in pressure loss have led to
    the development of electrostatically
    enhanced fabric filters and so-called
    hybrid devices



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          Allied Environmental Technologies, Inc. - MSC™ Development
        Hybrid Particulate Control Technology


l   A combination fabric filter/ESP hybrid
    device has been developed by EPRI and is
    called the Compact Hybrid Particulate
    Collector (COHPAC):
    l   This device involves using pulse jet fabric
        filtration to capture dust that escapes an ESP
         l COHPAC I involves placing a pulse jet filter
           downstream from an ESP
         l COHPAC II utilizes a fabric filter in place of the
           last field(s) of an ESP



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                Allied Environmental Technologies, Inc. - MSC™ Development
        Hybrid Particulate Control Technology

l   Advanced Hybrid
    l   This technology was developed and patented by
        the University of North Dakota’s Energy &
        Environmental Research Center (EERC)
    l   The internal geometry consists of alternating
        rows of ESP components (discharge electrodes
        and collecting plates) and filter bags within the
        collector
    l   The inlet flue gas is directed into the ESP zone,
        which removes most of the entrained dust prior
        to it reaching the filter bags

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                 Allied Environmental Technologies, Inc. - MSC™ Development
Hybrid Particulate Control Technology


l   ESFF
    l Electrostatically-stimulatedfabric filters
     (ESFF) have been developed by EPA to
     reduce fabric filter pressure drop and
     particle penetration




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           Allied Environmental Technologies, Inc. - MSC™ Development
Multi-Stage Collector
        (MSC™ )



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     Allied Environmental Technologies, Inc. - MSC™ Development
    Multi-Stage Collector - MSC™



l   The principal objective of the MSC™
    design is to substantially improve fine
    particulate collection by:
     l   combining electrostatic charging -
         collection and filtration processes, while
     l   separating zones for particles charging
         and collecting




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              Allied Environmental Technologies, Inc. - MSC™ Development
Multi-Stage Collector - MSC™


l   The MSC™ concept can be broadly
    summarized as a system in which
    multiple stages are utilized, with
    each stage performing a primary
    function and multiple stages
    operating synergistically to provide
    significantly improved overall results




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          Allied Environmental Technologies, Inc. - MSC™ Development
    Multi-Stage Collector - MSC™
l   The MSC™ offers a uniquely compact concept
    utilizing:
     l an upstream stage comprised of a conventional
       ESP,
     l followed by a downstream zone of the parallel
       surfaces creating uniform electric field,
     l followed by yet another stage, which
       incorporates barrier filter, surfaces of which
       provide yet additional zone with uniform
       electric field
l   Moreover, by providing continuously repeated
    stages in series, the downstream zones
    effectively re-charge and re-collect the particles
    that are either uncollected or reentrained and
    collect those particles after they have been
    charged
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            Allied Environmental Technologies, Inc. - MSC™ Development
             Multi-Stage Collector
                                                                                   Stage-3 (Barrier Filter): Filtration
                                                                                       Stage-3 (Barrier Filter): Filtration
                                       Stage-2 (Uniform Filed):
                                        Stage-2 (Uniform
                                  Stage-2 (UniformFiled): Filed):
                                    Stage-2 (Uniform Filed):
                                                 Precipitation
                                                 Precipitation
                                            Precipitation
                                           Precipitation




                                                                                                          +
                                                                                                              -
                                                                                                          +
                                                                                                            -
                                                                                                          +
                                                                                                            -
     Stage-1 (Non-Uniform Field): Charging
Stage-1 (Non-Uniform Field): Charging
                                                                                                          +
                                                                                                            -
                                                                                                          +

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                                Allied Environmental Technologies, Inc. - MSC™ Development
Multi-Stage Collector

                                                  Stage-3 (Barrier Filter):
                                                      Stage-3 (Barrier Filter):
                                                           Filtration
                                                                Filtration
  Stage-2 (Uniform Filed):
      Stage-2 (Uniform Filed):
        Stage-2 (Uniform Filed):
  Stage-2 (Uniform Filed):
          Precipitation
               Precipitation
               Precipitation
          Precipitation




     Stage-1 (Non-Uniform Field):
 Stage-1 (Non-Uniform Field):
           Charging
     Charging




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                 Allied Environmental Technologies, Inc. - MSC™ Development
         Multi-Stage Collector - MSC™

l   The MSC™ assembly
    is made up from DE’s
    placed between
    oppositely charged
    corrugated plates
l   The DE’s are followed
    by BFE’s located in
    wide zones placed
    between the collecting
    electrodes
l   The corrugated plates
    are held at a first
    electrical potential
    while the DE’s and the
    BFE’s are held at a    Both the flat sides of each of the DE’s,
    second electrical        corrugated plates and the surfaces
    potential                of the BFE form collecting surfaces
                             where the electric field is relatively
                             uniform                                25
                    Allied Environmental Technologies, Inc. - MSC™ Development
        Multi-Stage Collector - MSC™
                                                         The center region of uniform
                                                          The center region of uniform
                                                           field on the other hand acts
                                                             field on the other hand acts
                                                             in manner similar to the
                                                           in aa manner similar to the
                                                            field between parallel
                                                             field between parallel
At sufficiently high field
 At sufficiently high field                                capacitor plates with
                                                              capacitor plates with
   strength in this
    strength in this                                       charged dust particles
                                                             charged dust particles
   non‑uniform field                                       collecting on the plates of
                                                             collecting on the plates of
    non‑uniform field                                       opposite polarity
   region, aacorona                                           opposite polarity
    region, corona
   discharge can take
    discharge can take
   place between the
    place between the
   electrode and the
    electrode and the
   plates acting as an
    plates acting as an                                   +                       +
   ion-charging source
    ion-charging source
   for dust particles
    for dust particles
   passing through it
                                                          -                  -    -
    passing through it
                                                           +                      +

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                     Allied Environmental Technologies, Inc. - MSC™ Development
Evolution of Electrostatic Precipitation




                                                                    Courtesy of Aerosol & Particulate Research Lab



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       Allied Environmental Technologies, Inc. - MSC™ Development
         Evolution of Electrostatic Precipitation
                   Major Distinctive Points
                                                                                      Gas Flow
l   The MSC™ is engineered in such a way that the
    BFE and the DE are grounded while the corrugated
    electrodes are suspended from the insulators
l   By virtue of having the BFE’s at the same potential
    as the DE’s, the MSC™ design completely
    eliminates any potential sparks from the DE                                   +       -      +
    toward the BFE, thus eradicating any chances of
    causing fires and/or puncturing holes in the
    porous barrier media
                                                                                          -
l   Hence, whether the MSC™ is powered by a
    “conventional” or an alternating power source, the
    BFE’s remain protected from any sparks from the
    DE irrespective of dust concentrations                                        +       -      +

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                     Allied Environmental Technologies, Inc. - MSC™ Development
Computational
Fluid Dynamics
   Modeling

                                                               29
  Allied Environmental Technologies, Inc. - MSC™ Development
    CFD Simulation


l   In order to evaluate the MSC™ design, a
    detailed analysis of gas flow dynamics were
    performed with an aid of the Computational
    Fluid Dynamics (CFD) technique
l   CFD simulation was conducted for the pilot
    MSC™ consisting of four (4) rows of barrier
    filters (bags) four (4) bags each for a total of
    16 bags and five (5) collecting corrugated
    plates


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              Allied Environmental Technologies, Inc. - MSC™ Development
CFD Simulation
      3-D View of the CFD Model




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       Allied Environmental Technologies, Inc. - MSC™ Development
    CFD Simulation

l   The MSC™ operation was simulated for three (3)
    operating conditions with the gas flows of 0.24,
    0.47, and 0.69 m3/s at 149 ºC (500, 1,000, and
    1,500 acfm at 300 ºF) for the filtration velocity in
    the range of 5 – 15 cm/s (10-30 ft/m)
l   The operating pressure drop supplied by the
    bags was assumed about 6” WC
l   The simulation utilized body-fitted grid approach,
    which allows the use of non-orthogonal grids that
    can accurately represent geometry of the
    simulated object

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               Allied Environmental Technologies, Inc. - MSC™ Development
CFD Simulation
     CFD Model Computational Grid




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       Allied Environmental Technologies, Inc. - MSC™ Development
    CFD Simulation

l   The simulation was carried out using standard κ-ε
    turbulence model with the logarithmic wall functions
l   The turbulence intensity at the MSC™ inlet was
    assumed to be 5 %
l   Since the pressure drop inside MSC™ is small with
    respect to the atmospheric pressure, the equation of
    state of the gas used in the simulation was the one of
    the constant-density gas
l   The bags were simulated as the porous media of the
    constant resistance, which was adjusted to ensure
    predetermined pressure loss for the gas flow
    simulated

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               Allied Environmental Technologies, Inc. - MSC™ Development
CFD Simulation

   Velocity Distribution – 500 cfm Case




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        Allied Environmental Technologies, Inc. - MSC™ Development
CFD Simulation

   Velocity Distribution – 1000 cfm Case




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        Allied Environmental Technologies, Inc. - MSC™ Development
CFD Simulation

  Velocity Distribution – 1,500 cfm Case




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       Allied Environmental Technologies, Inc. - MSC™ Development
    CFD Simulation

              3D - Velocity Distribution


                  1,000 acfm
                     1,000 acfm


500 acfm
  500 acfm




                                                                          1,500 acfm
                                                                             1,500 acfm



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             Allied Environmental Technologies, Inc. - MSC™ Development
Applications



                                                              39
 Allied Environmental Technologies, Inc. - MSC™ Development
    MSC™ Applications



l   One of the most important MSC™
    design improvements is very high
    collection efficiency in a submicron
    (ultra-fine) region, which extends its
    potential use to a wide variety of the
    fine particulate/dust collection
    applications



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             Allied Environmental Technologies, Inc. - MSC™ Development
MSC™ Applications




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      Allied Environmental Technologies, Inc. - MSC™ Development
    MSC™ Applications

l   Ultra clean exhaust gases: “Vision 21”
l   Integrated Gasification Combined Cycle (IGCC): super-
    clean de-dusting process (synthetic) gases
l   Industrial mineral processing industries:
        l   In-process capture of the expensive product material
            and return to the process, i.e. metals, rock-dust,
            gold, etc.
        l   Post-processing super-clean de-dusting prior to
            exhaust to the atmosphere
l   Ultra-clean air de-dusting in high-tech, medical, biological
    and other similar applications
l   Multi-pollutant applications (SOx, NOx, Hg, etc.) via
    integrating (or impregnating) catalyst materials within the
    barrier filter
                                                                               42
                  Allied Environmental Technologies, Inc. - MSC™ Development
Case Study



                                                             43
Allied Environmental Technologies, Inc. - MSC™ Development
     Case Study

l   A Case Study was conducted in order to evaluate suitability
    and size requirements of the MSC™ for the “conventional”
    ESP retrofitting
l   The goal of the study was to evaluate whether it would be
    possible to fit the required barrier filter area and the
    respective ESP equipment in the existing casing
l   500 MW boiler-unit firing sub-bituminous coal was selected
l   The existing three (3) field ESP had two (2) casings, four (4)
    cells each with 20 gas passages on 229 mm (9”) centers
l   The collecting plates were 3.66 m (12’) long and 9.14 m (30’)
    high
l   This geometry resulted in a SCA of 38.87 m2/m3/s (197
    ft2/kacfm) at a gas flow of 826 m3/s (1,750,000 acfm) at 149 ºC
    (300 ºF)
                                                                             44
                Allied Environmental Technologies, Inc. - MSC™ Development
            Case Study
               Existing ESP (½)
                           Flue Gas
                           Flue Gas                               MSC™ Retrofit (½)
                                                                                   Flue Gas
Field 1




                                                Cell 4
Field 1




           Cell 1     Cell 2       Cell 3


               l    Each Cell: 20 GP @ 9” SP
 Field 2
 Field 2




               l    12’L x 30’H Plates
               l    1,750 kacfm
               l    SCA=197 ft2/kacfm
 Field 3
 Field 3




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                               Allied Environmental Technologies, Inc. - MSC™ Development
           Case Study

                                                                      SIMULATED PERFORMANCE DATA
                   ITEM                              UNITS
                                                                             Case A                   Case B
Barrier Filter Diameter                             cm - inch       15.24               6     12.7              5
Gas Flow                                           m3/s - acfm       826         1,750,000    826        1,750,000
MSC™                                                 Systems           2                2      2                2
Compartments per MSC™                                                  6                6      6                6
Compartment Length                                     m - ft         6.1              20     6.1               20
Compartment Width                                      m - ft        3.66              12     3.66              12
Effective Height                                       m - ft        7.32              24     7.32              24
Barrier Filter Elements                                                      14 x 24                  16 x 27
No. of Barrier      Filter   Elements      per
                                                                     336               336    432           432
Compartment
Barrier Filter Area per Compartment                  m2 – ft2       1,177         12,667     1,261         13,572
Barrier Filter Face Velocity                       cm/s – ft/m       5.81          11.52      5.46         10.75
Total Collecting Area                                m2 – ft2       29,485        317,376    32,950       354,673
                                                    m2/m3/s –
Effective SCA                                                       34.74              176   38.82          197
                                                    ft2/kacfm



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                               Allied Environmental Technologies, Inc. - MSC™ Development
     Case Study

l   Assuming that the MSC™ will be able to operate with the
    FV in the 5 - 6 cm/s (10 - 12 ft/m) range a reasonably
    suitable retrofit seems possible
l   Naturally, as the MSC™ operation is independent of the
    fly ash resistivity, there will be no need to evaluate the
    requirements for the FGC
l   Hence, this unit would be an ideal candidate for the
    “spot market” coal
l   The expected system performance should be within the
    “Vision 21” range; hence the expected outlet emissions
    (≤ 0.005 lb/MBtu) should satisfy requirements of any local
    air pollution control regulatory office

                                                                            47
               Allied Environmental Technologies, Inc. - MSC™ Development
Summary &
Conclusions



                                                              48
 Allied Environmental Technologies, Inc. - MSC™ Development
       Summary
l   The MSC™ technology is a novel, compact multi-
    stage collector for separating dust or fume from
    industrial gases, which is independent of
    electrical resistivity
l   This design should be particularly advantageous
    when the material to be collected consists mostly
    of a sub-micron and ultra-fine dust or fume
l   The MSC™ concept offers significant
    improvement over conventional ESP’s and BF’s
l   the MSC™ design completely eliminates any
    potential sparks from the DE toward the BFE,
    thus eradicating any chances of causing fires
    and/or puncturing holes in the porous barrier
    media

                                                                           49
              Allied Environmental Technologies, Inc. - MSC™ Development
        Conclusions

l   MSC™ solves the problem of excessive fine-
    particle emissions with conventional de-dusting
    technology
l   MSC™ is independent of the dust/fume resistivity
l   It greatly reduces the problem of higher emissions
    from conventional fabric filters and hybrid devices
    in the event of partial breaking, leakage or any
    system malfunctioning parts, and
l   It solves the problem of sparking and bags
    damaging in the hybrid particulate collectors


                                                                            50
               Allied Environmental Technologies, Inc. - MSC™ Development
        Conclusions

l   MSC™ overcomes hurdles that prevent operation
    of pulsejet filters at high filter velocity ratios
l   MSC™ requires significantly less BFE surface area
    than conventional barrier filter
l   Consequently, lower vessel size required to
    accommodate the MSC™ may result in the lower
    capital and operating costs
l   Finally, in the event the BFE leaks, the overall
    MSC™ performance would suffer less, due to the
    remaining ESP collection phenomena


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               Allied Environmental Technologies, Inc. - MSC™ Development
Multi-Stage Collector - MSC™




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      Allied Environmental Technologies, Inc. - MSC™ Development

				
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