Flue Gas Desulfurization/Gas Denitrification

Treatment of sulfur dioxide and nitrogen oxides emitted from power plants and industrial boilers.

Spray Nozzle Scrubbers

Overview: The absorbent is sprayed downward from a series of nozzles and scrubs the flue gas as it moves upward resulting in SO2 absorption.
Features: 1）Having a low pressure drop.
2)Scaling problems are less likely to occur.

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Overview: Limestone（CaCO ₃ ）slurry absorbs sulfur dioxide (SO ₂) in the absorber and a byproduct as gypsum is generated.
Features: 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.
Reaction: SO ₂ +CaCO ₃ +1/2H ₂ O
→CaSO ₃ ・1/2H ₂ O+CO ₂
CaSO ₃ ・1/2H ₂ O+1/2O ₂ +3/2H ₂ O

Overview: The absorber tower consists of a combination of MORETANA plates with packing materials. It can remove SO₂ efficiently from the flue gas.
Features: 1）Contact area between the gas and liquid is large.
2)Simple process enables the absorber design to be compact.

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Overview: Seawater is used as an absorbent to remove SO ₂ from the flue gas.The absorbed SO ₂ is oxidized to soluble sulfate by aeration before discharge to the sea.
Features: 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.
Reaction: SO ₂ +H ₂ O → HSO ₃ ^– + H ⁺
HSO ₃ ^– +1/2O ₂ → SO ₄ ^2- + H ⁺
HCO ₃ ^– + H ⁺ → CO ₂ +H ₂ O

overview: 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.
Features: 1) Higher gas speed in tower and compact structure.
2) High efficiency dust removal.
3) No plugging due to self-cleaning effect.

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Overview: 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.
Features: 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
Reaction: SO ₂ +Mg(OH) ₂ → MgSO ₃ + H ₂ O
SO ₂ +MgSO ₃ +H ₂ O→Mg(HSO ₃ ) ₂
MgSO ₃ +1/2O ₂ → MgSO ₄

Overview: Seawater is used as an absorbent to remove sulfur dioxide (SO₂) from the flue gas. The absorbed SO₂ is oxidized to soluble sulfate (SO₄^2-) by aeration before discharge to the sea.
Features: 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.
Reaction: SO ₂ +H ₂ O → HSO ₃ ^– + H ⁺
HSO ₃ ^– +1/2O ₂ → SO ₄ ^2- + H ⁺
HCO ₃ ^– + H ⁺ → CO ₂ +H ₂ O

overview: NaOH is used as an absorbent to remove sulfur dioxide (SO₂) from the flue gas. The absorbed SO₂ is discharged as Na₂SO₄ aqueous solution. .
Features: 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.
Reaction: SO ₂ +2NaOH → Na ₂ SO3 + H ₂ O
SO ₂ +Na ₂ SO ₃ +H ₂ O → 2NaHSO ₃
NaHSO ₃ +NaOH →　Na ₂ SO ₃ +H ₂ O
Na ₂ SO ₃ + 1/2O ₂ → Na ₂ SO ₄