Process and apparatus for the purification of waste air

摘要

A process for the purification of waste air comprises passing waste air containing entrained solids through a travelling filter bed (18) comprising a pourable filter medium falling under gravity and removing the filter medium charged with the solids removed from the waste air from the travelling filter bed. The filter medium can be regenerated (21) and recycled (22) to the travelling filter bed. Waste air which has been substantially purified of solids may be passed through one or more travelling adsorption beds (29) or fixed adsorption beds to remove gaseous and/or liquid substances from the waste air, and/or passed through a heat exchanger to recover heat from the waste air. The process is particularly applicable to purification of waste air from lacquer- spraying units (11)-(14). The purified air and/or recovered heat may be recycled to the spraying units.