Lean reflux process for high recovery of ethane and heavier components

摘要

A simple, efficient, and cost effective process for separating components of a feed gas, e.g., containing methane and heavier hydrocarbons has been devised. First, feed gas is condensed to provide a vapor component and a liquid component. The vapor component is divided into at least a first, major portion a second portion, and a remaining portion. The second portion is directed to a lean reflux absorber, and the remaining portion is condensed and fed to the top of the lean reflux absorber. A bottom fluid stream, generally a liquid intermediate product, is recovered from the bottom of the lean reflux absorber, and lean vapor is recovered from the top of the lean reflux absorber. The liquid component, the first, major portion of the first vapor component, the liquid product from the bottom of the lean reflux absorber, and the lean vapor from the top of the lean reflux absorber are all fed to different feed points on a cryogenic distillation column. An optional cold side reboiler may be used to bring the cooling and heating curves into a more parallel relationship to improve process efficiency.