Membrane Separation for Light Hydrocarbons Recovery in the Petrochemical Industry

For petrochemical processes, the key questions to solve are: how to reduce the discharged organic tail gas; how to reuse and recycle the discarded organic streams; what is the optimal recovery ratio to ensure the most efficient use of resources and the minimum impact on the environment? The current study examines a polyethylene plant to solve these problems. Optimising the emission reduction of olefin tail gas in polyethylene synthesis can improve the utilisation rate of waste resources and bring practical economic benefits to the factory. It can significantly reduce environmental pollution. The annual economic revenue and payback period are considered. The objective function with the recovery ratio as the principal degree of freedom is optimised. The light hydrocarbons are recovered by membrane separation from olefin tail gas of polyethylene synthesis. A range of membrane area and recovery ratio are identified and analysed, suggesting an optimal recovery rate. The results of the case study show that the recovery ratio of light hydrocarbons (C2+) is 53.6 %, which has a significant economic benefit.