A method for recovering light hydrocarbons from petrochemical plant tail gas

Abstract

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.

Description

technical field [0001] The invention relates to a tail gas treatment method, in particular to a method for recovering light hydrocarbons from petrochemical plant tail gas. Background technique [0002] Petrochemical plant tail gas (such as polyolefin plant tail gas, refinery tail gas, etc.) generally contains nitrogen and light hydrocarbons such as carbon 2, carbon 3, carbon 4, and carbon 5. The current treatment methods include incineration in an incinerator and direct discharge into the atmosphere , Absorbed into the atmosphere and other methods. The disadvantage of the incineration treatment method is that it causes a lot of waste of resources, and there are potential safety hazards because the tail gas may also contain oxygen. Direct discharge into the atmosphere not only wastes resources, but also causes serious environmental pollution. Most of the hydrocarbons can be recovered after being absorbed and discharged into the atmosphere. However, due to the increasingly s...

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Problems solved by technology

The disadvantage of the incineration treatment method is that it causes a lot of waste of resources, and there are potential safety hazards because the tail gas may also contain oxygen

Direct discharge into the atmosphere not only wastes resources, but also causes serious environmental pollution

Most of the hydrocarbons can be recovered after being absorbed and discharged into the atmosphere. However, due to the increasingly stringent environmental protection regulations, the discharge cannot be achieved, and the existing processes for recovering light hydrocarbons from petrochemical plant tail gas generally have low recovery rate, low product purity, and low investment. Big, high energy consumption, unstable operation and other problems

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