Fume scrubber water recycle

Fume scrubber water recycle. The steel finishing industry uses fume scrubbers to capture acid gases from pickling tanks. Scrubber water, which may contain a dilute caustic solution, is neutralized and recirculated continuously to adsorb the acid. Makeup water is added to replace water lost through evaporation and water that is blown down to end-of-pipe metals treatment. 

Particulate emissions can amount to as much as 0.25 tonne/tonne of pulp produced, particularly for an older pulp mill operating without controls (Table 15.13). Electrostatic precipitators, wet scrubbers, or occasionally both can achieve particulate containment of 95% or better [49]. The precipitator catch is returned to the black liquor stream for chemical recovery from the captured inorganic chemicals. Fumes lost from the dissolving tank vent are captured by demister pads or small low-energy scrubbers, which return the collected material to the green liquor circuit. Wet scrubbers are used for lime kiln dust containment. The waste liquor is used for slaking or other recycle functions in the lime circuit (Chap. 7), helping to decrease make-up chemical requirements and water emissions. 

Other gases, mist, and fumes may be treated by water scrubbing or, in case of ammonia, water containing phosphoric acid. In this case installation requires an anticorrosive lining. The scrubber liquors may be concentrated and recycled to the process. When recycling is not possible, wastewaters must be treated before they... 

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