Gas-permeation process economically recovers CO/sub 2/ from heavily concentrated streams

Use of carbon dioxide as an injection medium to increase oil production from existing reservoirs is becoming an important method of tertiary recovery. As the oil is produced, gas contaminated by the CO/sub 2/ also is produced. It is necessary and desirable to remove this CO/sub 2/ from the natural gas, and recompress and inject it into the reservoir. The remaining natural gas then can be sold or used for fuel. A gas permeation process, Delsep, has proven viable for CO/sub 2/ removal for natural gas streams containing as much as 80 mol % CO/sub 2/. Compared to conventional treatment methods for removing CO/sub 2/ from hydrocaarbon gas streams, Delsep can greatly reduce capital costs; eliminate all process heat requirements; provide a large reduction in electric power and fuel consumption; operate unattended and be easily automated (be packaged into modules for economic installation); add modules in stages to accommodate increased sour gas content in the inlet feed; and minimize space requirements.