Conceptual Process Design of CO2 Recovery Plants for Enhanced Oil Recovery Applications

Abstract

Processes for recovering CO2 (carbon dioxide) from CO2-rich gas are important in the CO2 EOR (enhanced oil recovery) field. From an environmental point of view EOR through the injection of CO2 is very beneficial because it allows for the storage of part of the CO2 injected while increasing oil recovery. To make this process even more environmentally friendly, the fraction of CO2 which exits (is produced from) the oil well can be captured and recycled for reinjection giving a more efficient CO2 storage strategy. The mixture of gases produced from an oil well contains light hydrocarbons, heavy hydrocarbons, water, and CO2. Dehydration units and numerous other separation units for separating CO2 and hydrocarbons can be used to recover CO2, so various potential configurations should be investigated to find the one which is most appropriate. In this study, the TEG (triethylene glycol) and adsorption dehydration processes are used for gas dehydration and a combination of amine, Selexol and distillation processes are used for CO2 separation. Unisim is used to simulate the processes and they are evaluated economically in terms of plant installation costs and energy consumption. A case study is presented to demonstrate the feasibility of various design configurations.