Gas processing

Abstract

A process for the recovery of C.sub.2 components (ethylene and/or ethane) and heavier hydrocarbon components from a gas stream containing a significant quantity of components more volatile than methane (e.g., hydrogen, nitrogen, and/or others) is disclosed. The cooled, partially condensed hydrocarbon bearing gas stream is separated into a vapor containing substantial quantities of the component(s) more volatile than methane and a liquid containing predominantly hydrocarbons. The vapor is expanded to the distillation column pressure and then supplied to the column at an upper mid-column feed position. The liquid is expanded to column pressure and supplied to the column at a lower mid-column feed position. A recycle stream is withdrawn from the column at a point below the upper mid-column feed position where the bulk of the volatile components are supplied to the column. The recycle stream is compressed and cooled so that a substantial portion is condensed and then supplied to the column as reflux at the top column feed position. The major portion of this reflux is liquid methane which allows the recovery of a significant portion of the C.sub.2 and heavier components that are in the vapors in the upper section of the distillation column. The distillation column overhead vapor contains predominantly methane and the more volatile components The major portion of the desired components is recovered in the distillation column bottom liquid product.