Solvent recovery from air, esp. in dry cleaning machines - where air flows up tank in counter:current to sprays of refrigerated solvent which strip and purify air

摘要

Air laden with solvent and leaving a degreasing or dry cleaning machine is fed into a tank, so it is exposed to sprays of the same solvent as that in the air, and pref. perchloroethylene (PCE). The pref. tank has a thermally insulated lining, and a low inlet for the contaminated air. In the upper part of the tank is a nozzle pipe, providing streams of cold PCE which flow downwards in counter-current to the air; and an exit for the purified air is located in the top of tank. In the base of the tank is a pump feeding PCE to the nozzle pipe, which is located above a cooler kept below 0 deg.C. An earlier solvent recovery plant used water sprays to wash the contaminated air; the present invention eliminates the need to use water.