Abstract: Aiming at the problems of frequent leakage and short life of the cyclic propylene compressor valve in polypropylene plant, it was foundthrough analyzing the failure factors of the air valve that improper selection of the air valve types was the main reason for the frequent fatigue fracture and the short life of the valve.Then the compressor valve was optimized through optimal selection of the valve type and the improvement of valve sheet material. Hence, the service life of the valvewas prolonged; the shutdown number of the cyclic propylene compressor was reduced; the pollution caused by propylene emission to the environment was avoided and meanwhile these created certain economic benefits.

Key words: cyclic propylene compressor, air valve, optimal selection, improving material quality