Updated: July 2002

1. Purpose

The exhaust gas discharge from municipal waste incineration plants contains harmful substances such as heavy metal containing mercury, or dioxin, etc. as well as HCl, SOx, dust, etc.
The system was developed to remove such substances at high efficiency and to be compact.

2. Flow

3. Performance

1) It is possible to remove 98-99% of HCl and SOx.
2) The dust removal ratio is 99.9% or over.
3) The heavy metal removal ratio is 99% or over.
4) The mercury can be removed at a removal ratio of 90% or over by adding a mercury removing agent.
5) It is possible to remove 80-90% of dioxin.

4. Features

1) The system can ensure the HCl, or SOx removal ratio equivalent to that of a wet type cleaning unit.
2) No discharge water treatment system is necessary.
3) Lower equipment cost and operation cost as compared with wet type system.
4) It is comparatively easy to prevent the white plume generated through the stack.
5) The coarse dust of fire dust contained in the exhaust gas is removed at the lower side of the quenching tower, to prevent the filter cloth from burning.
6) Since the gas flow upward within the quenching tower, the liquid drop sprayed is raised as slow speed, making it possible to fully secure the drying time.
7) It is possible to protect the filter cloth or the bag filter by using the special dose. Besides, the filtration dust layer is designed porous, to eliminate the pressure loss, and further to improve the neutralization of calcium hydroxide with acid gas, thus ensuring high removal ratio and limited consumption of calcium hydroxide.

5. Practical Application Example

19 plants, 44 units of semi-drying method at present, including the plant under construction, with the waste incineration plant as main. The system of this type is liable to further increase in the future.