(3b) Low Temperature Considerations for Centrifugal Compressor Casings in Ethylene Service

Centrifugal compressor casings with Ethylene process gas often have a Minimum Design Metal Temperature (MDMT) between -29°C and -115°C, and the design temperature may be even lower under certain conditions. Compressor casings are fabricated from various grades of carbon steel, low-alloy steel or stainless steel and follow the guidelines set forth by API 617. The material selection and the fabrication procedures utilized for is heavily dependent upon the Minimum Design Metal Temperature as this is the most critical and demanding design parameter of an ethylene compressor.

This presentation will review the low temperature limitations of steel alloys used for ethylene compressor casings, the testing which is used to qualify these materials for low temperature service, and the relative commercial impact of the alloy selection