Abstract:

The technical transformation of ethylene enrichment unit for dry gas with a capacity of 30,000 m3/h in PetroChina Sichuan Petrochemical Co., was conducted to process PSA desorption gas of catalytic reforming unit. The heavy component (≥C3) in the desorption gas is up to 13.52%, far more than the design value of 3%, that makes more condensate in the ethylene enrichment unit. The condensate is mainly composed of C3-C5 components and a small amount of water. An additional pipeline with heat tracer was set for delivering the condensate to the catalytic cracking unit for recycling. The results after revamping show that C2 and C2 above components in the gas can effectively be recovered, and at the same time the impurities of H2S，CO2 and O2 were removed. The ethylene enriched gas is a qualified feed for ethylene unit, and the net profit reaches 50.63 million Yuan/a after transformation.

Key words: pressure swing adsorption, dry gas, desorption gas, enrichment, ethylene