Turbo Expander Technology Contribution in Development of Ethylene Plant Process

Abstract

Lecture 8: Ethylene plant process and turbo expander technology developments have been interrelated and dependent on each other’s. Design improvements and technology innovations associated with inflow radial turbine, turbo expander, have been the main motivation for the improved and more productive ethylene plant processes. The early process design that was based on Jule Thompson expansion valve was replaced by the process designs that utilize several stages of expander -compressor or expander- generators. The latest technology innovation that was embraced by the ethylene plant engineering companies and the owners was expander-compressor with active magnetic bearings. The early applications of expander-compressor with magnetic bearings began in the 1980’s.<br.<br>The present product improvement activities by turbo expander suppliers are to reduced number of expansion stages. High head and low flow coefficient expander wheel as well as high peripheral speed wheels are being developed to achieve the latter objective. The next innovative technology that is knocking at the door of ethylene plants is expander - high speed permanent magnet generator with magnetic bearings. In this paper the authors present a brief history of ethylene plant process, expander technology developments and show their reliance. The authors will also present their suggestions about the next innovation of the expander with high speed generator.