Abstract
This article introduces the source and utility circumstance of off-gas in China. The utility circumstance of off-gas is discussed in detail. For example, off-gas is used to hydrogenate finely as synthesized ammonia material, alkylation of toluene and dilute ethylene in off-gas is applied to generate 1,3-dimethylethylbenzene, off- gas produceds ethyltoluene, off- gas is used to seal centrifugal compressors, and the flow chart of off-gas is concretely enumerated. According to the full utility of off- gas, its good economic and social benefit are obtained.