Carbon dioxide removal from anaesthetic gas circuits using hollow fiber membrane contactors with amino acid salt solutions

A novel technology based on the use of hollow fiber membrane contactors with regenerable liquid absorbents is proposed for carbon dioxide removal from anaesthetic closed breathing circuits. To analyse the performance of the contactor for this specific application and the influence of the system parameters, a 2D numerical model was developed for the transport of CO2 through the hollow fibers. The model considered potassium glycinate solutions as absorbents and a composite membrane made of a porous support layer and a dense thin layer. Both co- and counter-current operations were studied. The model simulation results were compared to those obtained with conventional mass transfer models, valid for limit conditions, and a good agreement was found. The analysis performed indicates that the use of hollow fiber membrane contactors with amino acid salt absorbent solutions is suitable for CO2 removal from closed anaesthetic circuits. Contactor design and operating conditions are suggested.