Classification of Technology:
Air Pollution Control Type of Industry:
Chemical; Petrochemical Subject:
Reduction of SO2 in Boiler Exhaust Gas
1. Purpose
According to the prefectural regulations on the total amount of discharge of SO2 from chimney stacks, SO2 must be reduced from 1200ppm to 5ppm.
2. Applied Technology and the Time
The Wellman Lord method for converting sulfur of heavy fuel oil to sulfuric acid was introduced in 1973. In line with the installation of the coal boiler in 1990, this was changed over to flue gas desulfurization with magnesium hydroxide based on both desulfurization rate and economic viewpoint.
3. Principle
SO2 + Mg(OH)2 -> MgSO3 + H2O
2MgSO3 + O2 -> 2MgSO4
Since magnesium sulfate ( MgSO4 ) is contained as a component of the sea water, and COD of the drain is also within the regulation value of under 50ppm, they are discharged into the river together with the factory drain.
4. Effect and Achievement
Before Countermeasure
After Countermeasure
1) Wellman Lord Method
After Countermeasure
2) Mg(OH)2 Method
SO2 discharge ppm
[ outlet of equipment ]
1200
20
5
5. What to do next ?
Since magnesium hydroxide slurry is handled, care will be required in order to prevent both erosion of the supply pump and blocking of the supply piping.
Implementing company:
Japan Synthetic Rubber Co., Ltd. Yokkaichi Plant
