Abstract: With the development of petrochemical production, chemical plants have become larger and been in large scale. And the key equipment has played a crucial role in their safety, reliability and efficiency during the process of production and operation. Taking the "three machines (cracking gas compressor, propylene compressor, and ethylene compressor)" in ethylene plant as an example, this paper analyzes from the aspects of equipment design, manufacturing, construction and operation management, and expounds how to improve the reliability of key units. This provides certain technical reference for the design, manufacture and use of large equipment in chemical industry.

Key words: key units, reliability, equipment management, countermeasures