Abstract: This paper studies the problems arose in the long period operation of cracking gas compressor due to light feedstock, including the shorter polymerization fouling period of compressor body, outlet pipes and inter-stage coolers, the decrease in operational efficiency of compressor, the increase in N Factor and first-stage suction pressure, and the rise in operational cost of compressor turbine. By analyzing the reasons for the shorter polymerization fouling period of compressor and the increase in N Factor and first-stage suction pressure, the injection volume of polymerization inhibitor and wash oil was optimized to control the increase of N Factor. A complete decoking of the compressor body and outlet pipes was performed during the overhaul to improve the operational efficiency of the compressor and reduce the inter-stage loss, so as to guarantee the stable, efficient and long period operation of the compressor.

Key words: light cracking feedstock, cracking gas compressor, fouling；N factor, first-stage suction pressure