Multiple weir scrubber

Abstract

A scrubber for removal of contaminants from gas by liquid contact. The scrubber has a gas and liquid tight containment walls, to contain a gas stream through the scrubber, and to allow recirculation of scrubbing liquid, without the need for external power. A plurality of preferably annular, downwardly extending underflow weirs arc provided to define therebetween a series of gas compartments. Preferably annular, upwardly extending overflow baffles are provided between adjacent underflow weirs, and liquid compartments are defined between the inner surface of an outer wall and the first overflow baffle, and between successive overflow baffles, if present. A charge of scrubbing liquid is provided, and gas is directed into the scrubber through an inlet nozzle, under the first underflow weir, over the first overflow baffle, and thence under the next underflow weir. Preferably, a mass transfer packing is provided in a tower after the last underflow weir, and more preferably, a final liquid level is maintained to allow flooding of the lower reaches of the mass transfer packing while gas is passed therethrough with sufficient velocity to attain efficient mass transfer. Mesh pad mist eliminators can also be provided before the clean gas exits the scrubber vessel. Alternately, parallelepiped shaped gas tight scrubbing units can be provided, containing a plurality of underflow weirs each followed by overflow baffles, where the overflow baffles include, near the bottom, liquid return apertures. The charge liquid can be changed by draining the scrubbing vessel and providing fresh scrubbing liquid.