Abstract: This paper analyzes the problems existing in the cracking gas compressor GB-201 of an ethylene plant covering the operation difficulty, low compressor efficiency and high energy consumption. It is found through the analysis that there are hidden equipment dangers in the unit including long service time, poor sealing performance and aging of the oil ring in the compressor body, internal gas blowby and three section outlet overpressure and so forth. Therefore, the compressor unit and its auxiliary equipment were updated as a whole by adopting a high-efficiency turbine driver with high pumping capacity and a high-efficiency ternary impeller compressor.After the revamp, the compressor efficiency was improved significantly under the same working condition, and the energy consumption of the device was improved effectively. This provides valuable experience in solving such problems for cracked gas compressors in ethylene plants.

Key words: cracking gas compressor, turbine, high pressure cylinder, low pressure cylinder