The invention provides a deep cooling and film coupled 
ethylene cyclic 
refrigeration system non-condensed 
effluent gas separating and recycling technology, and belongs to the technical field of 
petrochemical engineering. According to the technology, starting from the characteristics of an 
ethylene cyclic 
refrigeration system, deep cooling conditions formed through 
ethylene throttling expansion areutilized for conducting liquidation and rectification on non-condensed 
effluent gas, most of ethylene is recycled in the form of the 
liquid state, then, a gas film is used for separating and enriching ethylene left in deep cooling 
tail gas, and low-pressure ethylene-rich gas obtained on the 
permeation side returns to a compressor of the ethylene cyclic 
refrigeration system. Deep cooling and filmseparation 
coupling is adopted for treating the non-condensed 
effluent gas, and ethylene losses are obviously reduced while 
oxygen and 
nitrogen accumulation is avoided. Taking a 
butyl rubber device of60,000 tons / year as an example, by adoption of the provided efficient non-condensed effluent gas separating and recycling technology, the ethylene content of the 
tail gas exhausted towards a 
torch islower than 5.0 vol%, the ethylene recycling rate reaches 99%, about 210 tons of ethylene can be recycled every year, and the annual 
economic benefits exceed 2 million yuan.