Innovative contactor for CO2 recovery

CO₂ capture from pre- or post-combustion is a challenging way to control greenhouse gas emissions for a sustainable world. One of the most suitable techniques for the separation of gas is based on membrane. The use of hollow fibre contactors is very promising in gas-liquid absorption because of the high interfacial area which allows a higher transfer. However, for CO₂ absorption in chemical solvents, the transmembrane pressure should be less than 1 bar, which involves difficulties during desorption/absorption cycle. Then, some gradual wetting can occur, which does not allow stable process performances over time. This study explores a new strategy in order to avoid these problems by the use of composite hollow fibres, composed by a thin dense layer having high gas permeability, providing a physical separation between the gas and liquid and the hydrophobicity, and a micro-porous support, which brings the mechanical properties. We studied various micro-porous support (polypropylene, polyethersulfone, PVDF) and two dense layers (Teflon AF and PTMSP) depending of the absorption processes (chemical of physical). The virgin and coated HF were characterised by SEM, mechanical tests, pure water and CO₂ permeability, and also by their stability in the absorption solvents.