REDUCTION OF FINE PARTICULATE EMISSIONS FROM ESPs

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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
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• 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

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• WESP and wet scrubbers
• Barrier filters

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

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• Sneakage around the active system
• Re-entrainment
• Rapping re-entrainment
• Back corona
• Corona induced secondary rolls
• Maintenance level

but all particles can be caught
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We must continue to optimize - discharge
electrode design - energisation - rapping
system control

• and focus on two things
• Elimination of remaining non-ideal phenomena to
  approach laboratory conditions
• Field tests and investigations of fine
  particulate behaviour in ESPs for better
  understanding and development of new full scale
  features

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Perforated plate blocked by dust
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Gradual opening fully open fully
closed

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New baffle
Full utilisation of collecting area. No sneakage
or entrainment from hopper
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Process parameters - temperature - moisture -
flow rate ESP operation - rapping - corona
power - HV wave form
Influence on particle size ?
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• 3 field ESP _at_ 400 mm spacing, 0.6 m/s
• TR-operation 75-55 kV / 0.06-0.3 mA/m²
• ESP inlet 60 g/Nm3, 250-300C, 30 H2O

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On-line particle size distribution valuable
information for ESP design and optimisation
On-line low pressure impactor with dilution stages
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Very low conc.
High conc.
Distribution during Distribution
betweenrapping 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.

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Low concentration of fine particles
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• Particle size depended emission challenge
  particulate filters
• Electrostatic Precipitators have the potential
  and ability to meet very low emission levels
• Proper design, optimisation and testing becomes
  increasingly more important
• Eliminate non-ideal phenomena and let the
  electrostatic precipitation process control the
  emission a matter of ESP size
• Fine particle emission can be controlled by dry
  Electrostatic Precipitators

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Before upgrade 50 mg/Nm3
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Before upgrade 70-80 mg/Nm3
PM10lt0.33 mg/Nm3
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Before upgrade 15-25 mg/Nm3