Abstract: To solve the coking problem of cracking gas compressor (K-3101) in the ethylene plant at PetroChina Dushanzi Petrochemical Company, this paper introduces the coking inhibition mechanism of wash oil injection, water injection and polymerization inhibitor injection, and analyzes the axial force balance of high pressure cylinder (K-3101). The result shows that there is a direct relationship between the coking and the axial displacement of the impeller and internals of cracking gas compressor, and the severity of coking is positively correlated with the magnitude of axial displacement. By adopting inter-stage water injection technology and optimizing polymer inhibitor injection amount and wash oil injection time, the accumulation of polymer on the impeller and internals of compressor can be effectively inhibited, so that the axial displacement will gradually decrease.

Key words: cracking gas compressor, coking；axial force, axial displacement