The invention discloses a method for recycling light
hydrocarbon from
tail gas of a
petrochemical plant. The method comprises the steps that the
tail gas of the
petrochemical plant is compressed through a compressor and then condensed, and meanwhile
hydrocarbon substances which are dissolved out after condensation are recycled; the
tail gas with the
hydrocarbon substances recycled is heated and enters a membrane separation device to be separated, the gas on the permeable side of the membrane separation device enters the tail gas
raw material of the
petrochemical plant to conduct circulation again, the gas on the non-permeable side of the membrane separation device enters a
pressure swing adsorption system for
pressure swing adsorption, non-adsorptive gas which is obtained after
pressure swing adsorption is conducted is exhausted to the
atmosphere or recycled, and adsorptive gas which is obtained after pressure swing adsorption is conducted enters the
raw material tail gas to be circularly recycled or enters a gas
pipe network to be burnt after being resolved. According to the method for recycling the light hydrocarbon from the tail gas of the petrochemical plant, the investment is small, the
operating cost is low, the light hydrocarbon
recovery is high, the purity of the recycled light hydrocarbon is high, up-to-standard release of the tail gas is achieved, and meanwhile useful substances are recycled, energy sources are saved, and larger economic value is achieved.