Abstract: A method and a facility for wet-scrubbing sulfur dioxide to produce, for example, potassium thiosulfate or ammonium thiosulfate. The facility includes a multi-section vessel having multiple horizontally disposed stages where a preceding stage passes partially-scrubbed waste gas to a succeeding stage. Each stage has a scrubber mechanism to scrub waste gas with circulating fluid that successively reduces waste gas concentration before atmospheric discharge. The scrubber mechanism may include a packing to facilitate absorption of waste gas by the fluid, a sump disposed at the output of the stage to receive fluid as it drains from the packing, and a circulation pump to circulate fluid from the sump to its packing and to cascade at least a portion of the fluid back to a preceding stage. A portion of the fluid is extracted from the facility and reacted in a reaction vessel with a cation to produce ammonium thiosulfate or potassium thiosulfate.

Abstract: A method of wet-scrubbing a waste gas containing sulfur dioxide (SO2) to produce potassium thiosulfate. The wet-scrubbing facility includes multiple horizontally disposed stages where a preceding stage passes partially-scrubbed waste gas to a succeeding stage. Each stage has a scrubber mechanism to scrub waste gas with circulating fluid that progressively reduces SO2 in the waste gas before atmospheric discharge. The scrubber mechanism may optionally include a packing material to facilitate absorption of SO2 by the fluid, a sump disposed at the output of the stage to receive fluid as it drains from the packing, and a circulation pump to circulate fluid from the sump to its packing and to cascade at least a portion of the fluid back to a preceding stage. A portion of the fluid is extracted and reacted in a reaction vessel with a cation to produce potassium thiosulfate.