Alternative extractive distillation system for CO2-ethane azeotrope separation in enhanced oil recovery processes

摘要

CO2 is a common constituent of natural gas. Standards for its maximum concentration differ from about 2% for pipeline to 50 ppm for liquefaction. All natural gas constituents absorb CO2 to some degree when in the liquid phase, requiring multi-step natural gas treatment processes. The existence of a minimum boiling temperature azeotrope between ethane and carbon dioxide particularly complicates CO2 separation. Extractive distillation with higher molecular weight hydrocarbons as the solvent represents the most competitive means for the separating CO2 from ethane. The conventional separation method involves two distillation columns in series and rather high amount of energy.