Qualification of membranes for subsea CO₂ separation based on tests from lab scale to small-industrial scale

Subsea CO₂ separation demands non-classical requirements for membrane application due to constraints of process operation conditions that are different to topside gas processing. COMPMEM is a joint industrial project initiated by Aker Carbon Capture (ACC) aiming at the validation and pilot scale demonstration of the concept of subsea separation of CO₂ from a CO₂ rich well stream. The well stream could be originated from a back produced CO₂ rich flow from a CO₂ flooded oil reservoir or a CO₂ rich gas from a gas field. Firstly four membranes of commercial brands or near-commercial stage developed have been tested in lab scale at the conditions relevant to subsea gas separation within the broad range of temperature (40-90 oC), feed (35-90 bar) and permeate (2-35 bar) gas pressures, and CO₂ content in the feed gas (10-90%) with statistical design of experiments. Only two membranes were qualified based on the result of the lab scale gas permeation test and material compatibility test under harsh sub-sea conditions. The two membranes have been tested at harsh subsea conditions with real LNG/CO₂ blend in pilot scale membrane permeation test facility in SINTEF Industry.