HomePlant EngineeringWaste Gas Treatment：Flue Gas Desulfurization
Waste Gas Treatment
Flue Gas Desulfurization/Gas Denitrification
Treatment of sulfur dioxide and nitrogen oxides emitted from power plants and industrial boilers.
Spray Nozzles Scrubbers
- Flue Gas Desulfurization System
- Limestone Process
MORETANA Scrubbers
- Flue Gas Desulfurization System
- Mg(OH)2 Process, Seawater Process, Sodium Hydroxide Process
NEOBRID Scrubbers
- Flue Gas Desulfurization System
- Seawater Process
Contact treatment with catalyst
- Gas Denitrification System
- Catalyst system (Dry process)
Spray Nozzle Scrubbers
- The absorbent is sprayed downward from a series of nozzles and scrubs the flue gas as it moves upward resulting in SO2 absorption.
- 1) Having a low pressure drop.
2) Scaling problems are less likely to occur.
Limestone Process
- Limestone (CaCO3) slurry absorbs sulfur dioxide(SO2) in the absorber and a byproduct as gypsum is generated.
- 1) Cheap absorbent (limestone), low operating cost.
2) Producing a gypsum by-product to be collected.
3) The amount of wastewater discharge is the smallest. 
- SO2+CaCO3+1/2H2O
→CaSO3・1/2H2O+CO2
CaSO3・1/2H2O+1/2O2+3/2H2O
NEOBRID Scrubbers
- The absorber tower consists of a combination of MORETANA plates with packing materials. It can remove SO2 efficiently from the flue gas.
- 1) Contact area between the gas and liquid is large.
2) Simple process enables the absorber design to be compact.
Seawater Process
- Seawater is used as an absorbent to remove SO2 from the flue gas. The absorbed SO2 is oxidized to soluble sulfate by aeration before discharge to the sea.
- 1) The absorbent is seawater, no other reagents are necessary.
2) Simple system, easy operation and maintenance.
3) No by-product is generated.
4) The spent seawater can be discharged to sea after aeration. - SO2+H2O → HSO3- + H+
HSO3- +1/2O2 → SO4 2- + H+
HCO3- + H+ → CO2 +H2O
[Flue Gas Desulfurization System] MORETANA Scrubbers
- MORETANA is the name given to the perforated plate that has high open area ratio between 25%-60%. It promotes the contact between gas and liquid efficiently and can also treat flue gas containing dust.
- 1) Higher gas speed in tower and compact structure.
2) High efficiency dust removal.
3) No plugging due to self-cleaning effect.
Mg(OH)2 process
- Mg(OH)2 is used as an absorbent to remove sulfur dioxide (SO2) from the flue gas. The absorbed SO2 is discharged as MgSO4 aqueous solution.
- 1) Magnesium hydroxide is another cheap absorbent similar to limestone.
2) Relatively simple and compact system resulting in easy operations and maintenance.
3) No scaling problems.
4) MgSO4 can be discharge to sea. - SO2+Mg(OH)2 → MgSO3 + H2O
SO2+MgSO3+H2O→Mg(HSO3)2
MgSO3+1/2O2 → MgSO4
Seawater Process
- Seawater is used as an absorbent to remove sulfur dioxide (SO2) from the flue gas. The absorbed SO2 is oxidized to soluble sulfate (SO42-) by aeration before discharge to the sea.
- 1) The absorbent is seawater, no other reagents are necessary.
2) Simple system, easy operation and maintenance.
3) No by-product is generated.
4) The spent seawater can be discharged to sea after aeration. - SO2+H2O → HSO3- + H+
HSO3- +1/2O2 → SO42- + H+
HCO3- + H+ → CO2 +H2O
NaOH Process
- NaOH is used as an absorbent to remove sulfur dioxide (SO2) from the flue gas. The absorbed SO2 is discharged as Na2SO4 aqueous solution.
- 1) Simple system and easy maintenance.
2) No scaling problems.
3) Highest SO2 removal efficiency.
4) Producing Na2SO4 as a by-product to be collected. - SO2+2NaOH → Na2SO3 + H2O
SO2+Na2SO3+H2O → 2NaHSO3
NaHSO3+NaOH → Na2SO3 +H2O
Na2SO3 + 1/2O2 → Na2SO4