Process for separating a column overhead product

摘要

The present invention is an improvement in the combined fractionation steps of deethanization and C2 splitting for ethylene and ethane separation. Theoretical stages are added to the rectification section of a deethanizer above a liquid or vapor sidedraw. Polymer grade ethylene product up comprising to 30 percent of the ethylene in the deethanizer feed is obtained in an overhead stream according to the present invention. Lesser recovery at the same ethylene purity or higher recovery at lower ethylene purity are obtained varying recovery or numbers of additional stages in the rectification. An overall reduction in total cold utilities for the overhead condensers for the deethanizer and downstream C2 splitter are obtained in practicing the present invention.