Comparison Table

Process

Principle

Advantages

Drawbacks

Dry

  • Dry injection of
    Ca(OH)2
  • Simplicity of design
  • low investment costs
  • high flexibility (temperature and capacity)
  • No liquid effluents
  • Possibility of removing micro-pollutants by adding a specific reagent
  • Need to use a high quality corbent to lower consumption of the reagent
  • Large production of residues (unreacted reagent)

Semi-wet

  • Spraying of milk of lime
  • Cheapest sorbent: CaO
  • Absence of liquid effluents
  • Possibility of adding a dry injection to improve flexibility and extend the level of performance (3/4 dry process)
  • Difficulty coping with unstable flue gas conditions
  • Clogs easily
  • Milk of lime preparation
  • Maintenance operation

WET    

  • Neutralisation of pollutants with a scrubbing liquor
  • High efficiency
  • low consumption of reagent
  • Cheap reagent
  • High investment
  • Effluent Management : Water & Plume
  • Limitation of removal of minor pollutants (SO3, Dioxin, Hg)
  • Not suited for the removal of dioxins
  • Maintenance