Abstract: A process is disclosed for treating particle-containing gas streams by removing particles and gaseous atmospheric pollutants. Parallel passage contactors are utilized to remove the gaseous pollutants. The minimum required gas flow rate for effective operation of these contactors is maintained by recycling a variable amount of low temperature gas which has been passed through a particle removal zone. The recycled gas is reheated by heat exchange against a portion of the treated gas.

Abstract: An improved sulfur recovery process is disclosed. Sulfur oxides are removed from stack gases with an acceptor. Sulfur oxides are recovered from the acceptor in a periodic regeneration step. The sulfur oxides in the regeneration off gas are concentrated by use of an absorber-stripper. The absorber absorbs sulfur oxides with an absorbent, and the stripper liberates concentrated sulfur oxides from the absorbent. Key feature of the process is use of two vessels to contain absorbent. Only when significant amounts of sulfur oxides are being absorbed is absorbent sent to a rich absorbent holding tank. Regenerated absorbent and absorbent from the absorber which does not contain much sulfur oxides are sent to the lean absorbent tank. Main advantage of operating with two tanks is optimum use of the stripper, which is fed with absorbent containing a constant and high concentration of sulfur oxides.