Patent ID: 7207192

Claim:
A process for deethanizing a light hydrocarbon stream comprising olefins, comprising: feeding one or more light hydrocarbon streams comprising ethylene, ethane, propylene and propane to a primary deethanizer having absorption and stripping sections at a primary deethanizer pressure; refluxing the absorption section of the primary deethanizer to produce a rectified stream or streams containing less than 1 mole percent propylene and propane, wherein the rectified stream or streams together comprise from 80 to 99 percent of the feed ethane; reboiling the stripping section of the primary deethanizer to produce a primary deethanizer bottoms stream comprising from 1 to 20 percent of the feed ethane; feeding the primary deethanizer bottoms stream to a secondary deethanizer having absorption and stripping sections at a pressure less than the primary deethanizer pressure; refluxing the absorption section of the secondary deethanizer to produce an overhead vapor stream of ethane essentially free of ethylene; and reboiling the stripping section of the secondary deethanizer to produce a deethanized stream essentially free of ethane.