No. 037
Classification of Technology:
Air Pollution Control
Type of Industry:
Chemical; Petrochemical
Subject:
Reduction of Smoke Dust in Boiler Exhaust Gas
1. Purpose
To keep the concentration of the smoke dust discharged from coal boilers under 0.03g/mN3 in accordance with prefectural regulation.
2. Applied Technology and the Time
A bag filter type dust collector was adopted as the dust removing equipment to attain a dust emission standard of under 0.03 g/mN3 when the coal boiler was installed in 1990.
3. Principle
The exhaust gas of about 150°C discharged from the boiler enters the bag filter chamber where dust is removed on the outer side of the filter cloth suspended from the cell plate, and is discharged as clean gas from the inside of the filter cloth.
The bag filter chamber is divided into 6 chambers with 450 filter cloths suspended in each chamber for a total of 2,700pcs.
Clogging of the filter cloth is prevented by causing the dust adhering to the outer surface of the filter cloth to be dropped into a hopper by means of the pulse cleaning air jets periodically from a rotating manifold mounted on the cell plate.
The interval of the pulse cleaning air is set so the pressure difference on the filter cloth is about 100mmAq.
4. Effect and Achievement
Operation is carried out with a bag filter outlet dust concentration of 0.025g/mN3 as compared with the inlet dust of 4 ~ 17g/mN3.
Operation at under 0.010g/mN3 is also possible if there is no leakage in the cell plate packing.
Although the bag filter will be bypassed when the boiler fuel is changed from coal to heavy oil, the regulation value of dust can be attained with desulfurization equipment installed downstream.
5. Future Subject
Although the physical properties tests are conducted with samples for diagnosis of deterioration of the filter cloth, there is no appropriate guide on damage or deterioration, so there is a tendency towards over maintenance to avoid damage of the filter cloth during operation.
Implementing company:
Japan Synthetic Rubber Co., Ltd. Yokkaichi Plant
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