Semi-Dry Scrubber

Semi-Dry Scrubber can be considered as an intermediate between dry scrubber and wet scrubber. They involve usually the injection of humidified lime or hydrated lime or a spray of lime slurry into a reactor vessel to capture acid gases.

The capture of heavy metals and semi-volatile organic compounds can be carried on simultaneously with the acid gas capture or in a second stage by the injection of lignite coke or activated carbon.

The sorbent then dry as it reacts with the acid gases in the flue gas meanwhile the heavy metals and semi-volatile organic compounds are adsorbed on the sorbent.

The dried solid product residue remains entrained in the flue gases and is removed in a dust collector. The collected residue contains a mix of reacted and unreacted sorbent therefore it may be recycled to enhance sorbent utilization.