Abstract: Horizontal gas-liquid scrubbing systems and associated gas scrubbing methodologies are provided. In one embodiment, a horizontal duct scrubbing system includes a horizontally disposed housing having a waste gas inlet and a treated gas outlet, a liquid inlet manifold disposed within the horizontally disposed housing, the liquid inlet manifold comprising a plurality of nozzles oriented to spray a scrubbing liquor co-current to the flow of a gas stream flowing through the horizontally disposed housing, and a demister located proximal the treated gas outlet, where the horizontally disposed housing is substantially free of flow deflection members between the liquid inlet manifold and the demister. The gas stream may include sulfur dioxide, and the system may be capable of removing at least 71 vol. % sulfur dioxide from the gas stream.

Abstract: Method and apparatus for removing sulfur dioxide from stack gases. The stack gases are scrubbed with an aqueous wash liquid containing one or more alkali metal compounds which react to form the bisulfite, sulfite and sulfate salts of the alkali metal. The spent absorbent liquid effluent is then treated with calcium compounds in at least two separate reaction stages, the conditions of ion concentration and pH of the first stage being maintained to favor the precipitation of calcium sulfate in the presence of SO.sub.3.sup.= ions. In the succeeding reaction stages the precipitation of the desired amount of SO.sub.3.sup.= ions is carried out to form calcium sulfite. The resulting compound of calcium with sulfite and sulfate (which may in part be in the form of mixed crystals) are removed and the regenerated liquid is recycled.

Abstract: Method and apparatus for removing sulfur dioxide from stack gases. The stack gases are scrubbed with an aqueous wash liquid containing one or more alkali metal compounds which react to form the bisulfite, sulfite and sulfate salts of the alkali metal. The spent absorbent liquid effluent is then treated with calcium compounds in at least two separate reaction stages, the conditions of ion concentration and pH of the first stage being maintained to favor the precipitation of calcium sulfate in the presence of SO.sub.3.sup.= ions. In the succeeding reaction stages the precipitation of the desired amount of SO.sub.3.sup.= ions is carried out to form calcium sulfite. The resulting compounds of calcium with sulfite and sulfate (which may in part be in the form of mixed crystals) are removed and the regenerated liquid is recycled.