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									REDUCTION OF FINE PARTICULATE
    EMISSIONS FROM ESPs

   Karsten S. Poulsen & Carsten R. Lund

                 FLSmidth Airtech
                  Ramsingsvej 30
                  DK-2500 Valby
                    Denmark




   ICESP X – Cairns, Australia

                         ICESP X – June 2006
          Reduction of fine Particulate Emissions from ESPs   Slide 1
Agenda

• Background on fine particulate emission

• Our experiences from the path toward ideal
 performance of dry ESPs including:

   FLSmidth Airtech Vortex Free Baffles

   on-line particle size stack-testing

   a new case story (+5 in the paper)

• Conclusion on dry ESP application for fine
 particulate removal

                             ICESP X – June 2006
              Reduction of fine Particulate Emissions from ESPs   Slide 2
Particles - a rare sight in the future

  A trend for decades…
  • Reduced dust emission limit


  Recent years…
  • Limit on peak emission levels
  • ½hour mean values etc.

  Today - increasing focus on…
  • Particle size depended emission
         PM10, PM2.5, PM1, …
    both for vehicles and industry
    for public health reasons
                              ICESP X – June 2006
               Reduction of fine Particulate Emissions from ESPs   Slide 3
Ways to overcome the challenges...
 • WESP and wet scrubbers
 • Barrier filters

 …or by dry ESP technology
 • Discharge electrode design - optimised
 • Particle charging – pulse energization
 • Increased particle size - agglomerator

   Fibulax type                Fibulax type
   U2546                       V2050
                  Fix
                  point
                                                                                         40
                                                                                            100
                                                                                           80
                                                                                          60                                                      C1 F1
                                                                                      0 20I
                                                                                            100
                                                                                           80
                                                                                          60
                                                                                         40
                                                                                      0 20U
                                                                                          E
                                                                                          60100
                                                                                           80
                                                                                         40 IE U                  7 89                      IE IC T
                  Oval cross                                                            20
                                                                                      0 D       U P                45 6                      U U U
                                                                                                                                           LII SE C
                  section                                                                 C     D ULP              123                       T D T
                                                                                                                                                 P U
                                                                                                                                             D T O
                                                                                                C UL
                                                                                                ST SE
                                                                                                    S
                                                                                                                   0PA
                                                                                                                             E              P E M
                                                                                                                                            U ULFA
                                                                                                                                             C C R   P
                                                                            100                 AT DS
                                                                                                    S
                                                                                                    E               SS     NT               P M UL
                                                                                                                                           UL SEST
                                                                                                                                             S LI O  A
                                                                                                U CUE                W E P u lsET MIiz aN  UL C R
                                                                                                                                           SE eR Non
                                                                                                                                            e en r g
                                                                                                                                                     S
                                                                                                                                                     ti
                                                                            80                   S PP D C e n er g iz a tio n
                                                                                                    R               OR R/                    - S U
                                                                                                                                           SE EP A
                                                                                                                                                 T A E
                                                                                                   SP
                                                                                                    E                D R                   SE .R AL
                                                                                                                                           SPB       M
                                                                                                                                                     LI
                                                Precipitator voltage [kV]




                                                                                                   LY                                                S
                                                                            60
                                                                                                   A
                                                                                                   P.                      ES               T- AT MI
                                                                                                                                            AA       P
                                                                                                                                                     E
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                                                                                                   AT                                       A LI R
                                                                                                                         B a s e v o lta g eK )
                                                                                                                                     DC
                                                                                                                                             K
                                                                                                                                             (U
                                                                                                    E                                       C
                                                                                                                                           SE MI C
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                                                                                                   R                                        K T H
                                                                                                                                            R
                                                                             0
                                                                                                   AT                                      AT
                                                                                  0     2     4    6E 8 T im 0 [m s1 2 1 4 E 1 6 1 8 2 0
                                                                                                                  1
                                                                                                                    e         ]




                                                             ICESP X – June 2006
                                              Reduction of fine Particulate Emissions from ESPs                                                           Slide 4
Laboratory scale ESPs...

 • Everything works better
   than in real life
 • Zero emissions
 • Correlations are good
 • Ideal conditions and full control




   Under the right circumstances the same
   potential is there for full scale dry ESPs



                              ICESP X – June 2006
               Reduction of fine Particulate Emissions from ESPs   Slide 5
Full scale ESP performance is challenged
 • Sneakage around the active system
 • Re-entrainment
 • Rapping re-entrainment
 • Back corona
 • Corona induced secondary rolls
 • Maintenance level

 • The most hazardous dust
   is most difficult to catch
    Reduce total emission
      to ‘0’ reduce the fines
      (and heavy metals)
                              ICESP X – June 2006
               Reduction of fine Particulate Emissions from ESPs   Slide 6
The way ahead – fine particle removal...

 We must continue to optimize
     - discharge electrode design
     - energisation
     - rapping system & control

 …and focus on two things
 1. Elimination of remaining non-ideal
    phenomena to approach laboratory
    conditions
 2. Field tests and investigations of fine
    particulate behaviour in ESPs for better
    understanding and development of new
    full scale features
                              ICESP X – June 2006
               Reduction of fine Particulate Emissions from ESPs   Slide 7
No 1 Elimination of sneakage...


                                                …a combination of
                                                 these is common

 Old




       Conventional




                                      Ideal

                            ICESP X – June 2006
             Reduction of fine Particulate Emissions from ESPs      Slide 8
Conventional Baffles...non-ideal
Side view – bottom, between two series fields




Perforated plate
blocked by dust
                   Recirculation and turbulence

                                 ICESP X – June 2006
                  Reduction of fine Particulate Emissions from ESPs   Slide 9
Vortex Free Baffles – between fields
                                                        Gradual opening



                                                                 fully open



                                                                 fully closed




                            ICESP X – June 2006
             Reduction of fine Particulate Emissions from ESPs                  Slide 10
Vortex Free Baffles – ideal
Side view – bottom, between two series fields




New baffle
                 Full utilisation of collecting
                 area. No sneakage or
                 entrainment from hopper
                                 ICESP X – June 2006
                  Reduction of fine Particulate Emissions from ESPs   Slide 11
No 2 Field tests at a cement kiln bypass

Process parameters
     - temperature
     - moisture
     - flow rate


ESP operation
     - rapping
     - corona power
     - HV wave form



                                ICESP X – June 2006
                 Reduction of fine Particulate Emissions from ESPs   Slide 12
Operating data - cement kiln by-pass




  • 3 field ESP @ 400 mm spacing, 0.6 m/s
  • TR-operation           75-55 kV / 0.06-0.3 mA/m²
  • ESP inlet              60 g/Nm3, 250-300°C, 30% H2O


                                  ICESP X – June 2006
                   Reduction of fine Particulate Emissions from ESPs   Slide 13
Particle Size Measurement...




On-line particle size
distribution – valuable
            On-line low pressure impactor
information for ESP design
            with dilution stages
and optimisation

                              ICESP X – June 2006
               Reduction of fine Particulate Emissions from ESPs   Slide 14
Cement kiln bypass – effect of rapping
                                12                                                                                 0.25




                                                                                      Concentration [mg/m³] mass
Concentration by mass

                                10
                                     High conc.                                                                              Very low conc.
                                                                                                                    0.2
       Mass dM/dlogDp [mg/m³]




                                                                                                            by
                                 8
                                                                                                                   0.15




                                                                                             Mass dM/dlogDp
                                 6

                                                                                                                    0.1
                                 4


                                                                                                                   0.05
                                 2


                                 0                                                                                   0
                                  0.01     0.1             1               10                                         0.01        0.1              1        10

                                             Dp µm                                                                                      Dp µm
                                                 Dp [um]                                                                                 Dp [um]




    Distribution during                                                                                 Distribution between
    rapping                                                                                             rapping spikes

    • Rapping loss mainly coarse particles – optimisation reqd
    • Fine particles in control by the elec. precip. process
    • Average dust emission 1-7 mg/Nm3 – low conc.

                                                                          ICESP X – June 2006
                                                           Reduction of fine Particulate Emissions from ESPs                                           Slide 15
A selection of low emission dry ESPs

Pelletizer for     3 new ESPs <5mg/Nm3
iron ore
Zink roaster       2 upgrades in existing casings
                   PM2.5 = 1-10mg/Nm3
Cement kiln        1 new ESP <10mg/Nm3

Lime kiln          New ESP+GCT <6mg/Nm3
                   PM10 <0.33 mg/Nm3
Lime kiln          Baffle upgrade <8mg/Nm3


     Low concentration of fine particles…


                                ICESP X – June 2006
                 Reduction of fine Particulate Emissions from ESPs   Slide 16
Conclusion
 1. Particle size depended emission challenge
    particulate filters
 2. Electrostatic Precipitators have the
    potential and ability to meet very low
    emission levels
 3. Proper design, optimisation and testing
    becomes increasingly more important
 4. Eliminate non-ideal phenomena and let the
    electrostatic precipitation process control
    the emission – a matter of ESP size
 5. Fine particle emission can be controlled by
    dry Electrostatic Precipitators

                             ICESP X – June 2006
              Reduction of fine Particulate Emissions from ESPs   Slide 17
Pelletizer, Sweden – 3 new ESPs




                           ICESP X – June 2006
            Reduction of fine Particulate Emissions from ESPs   Slide 18
Zink roaster, Australia – 2 upgr. (internals)




                                                                   Before upgrade
                                                                    50 mg/Nm3




                              ICESP X – June 2006
               Reduction of fine Particulate Emissions from ESPs                    Slide 19
Cement kiln, Netherlands – new ESP




                           ICESP X – June 2006
            Reduction of fine Particulate Emissions from ESPs   Slide 20
Lime Kiln, Sweden – new ESP+GCT




                                                                Before upgrade
                                                                70-80 mg/Nm3




    PM10<0.33 mg/Nm3


                           ICESP X – June 2006
            Reduction of fine Particulate Emissions from ESPs                    Slide 21
Lime kiln, Denmark – baffle upgrade




                                                                 Before upgrade
                                                                 15-25 mg/Nm3




                            ICESP X – June 2006
             Reduction of fine Particulate Emissions from ESPs                    Slide 22

								
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