The removal and recovery of organic vapors from contaminated gas streams by means of membrane separation is finding increasing acceptance. At present about 50 commercial membrane based vapor recovery systems are in operation worldwide. The largest application in this area is the recovery of hydrocarbon vapors from off-gases emitted from gasoline tank farms. At the end of 1993, 24 hydrocarbon vapor recovery units (VRU's) based on membrane technology were in operation 19 in Europe, 5 in Japan). The size of these plants differ from 100 to 2000 m 3/h. The VRU's are single stage membrane units or hybrid systems of membrane separation combined with a post-treatment as catalytic incineration, gas engine or pressure swing adsorption. The latest development is a pilot plant to treat the off-gases generated by car refuelling at gasoline stations. All the european VRU's are equipped with membranes and modules developed at the GKSS Research Center. The membrane and module configuration is described in this paper. The basic design of three different VRU's is explained. Other industrial applications of membrane technology for organic vapor recovery are emerging. Examples are dichloroethane recovery from off-gas in the chemical industry, toluene recovery from vacuum dryers and the recovery of chlorofluoro hydrocarbons.
ASJC Scopus subject areas
- Environmental Engineering