Classification of Technology:
Air Pollution Control Type of Industry:
Paper/Pulp Subject:
Dust Removal and Desulfurization Using Scrubbers
1. Purpose
This scrubber is used with the objective of treating exhaust gas that has passed through an electric dust-precipitator on the recovery-boiler and for desulfurizing exhaust gas from the oil-fuel boiler.
2. Principles and structure
This is a so-called cyclone scrubber, with a structure as shown in Fig. 1.
Gas enters the main scrubber unit in a tangential direction, rising as it creates a swirling motion. At the same time, liquid is sprayed out radially from the spray nozzles in the center. The net effect is that dust is collected by the swirling motion of the gas and the radial motion of the droplets.
The main reaction taking place in the absorption process is as follows:
2NaOH + SO2 Na2SO3 + H2O
The side reaction is:
Na2SO3 + SO2 + H2O 2NaHSO3
The sodium and sulfur compounds generated by the absorption reaction can be used effectively as pulping chemicals.
The main specifications for the dust-removal scrubber are as follows:
1) Treated gas:
488,000 m³/h, at 150
2) Dust content at loading port:
0.35 g/Nm3
3) Dust content at discharge port:
0.12 g/Nm3
4) General dimensions
Body diameter: 6,800 mm
Total height: 50,000 mm
Example of application at pulp plant please refer to Fig. 2.
Implementing company:
Oji Paper Co., Ltd., Kasugai Plant