Study of an innovative gas-liquid contactor for CO2 absorption

Abstract

The absorption of CO2 from a CO2/N2 mixture is investigated using a membrane gas absorption process. In order to avoid any wetting problem and maintain optimal the removal efficiency, composite membranes, with a porous support coated by a dense layer, are used. Two composite membranes are studied: Oxyplus® and a polypropylene (PP) porous fiber coated by poly(1trimethylsilyl-1-propyne) (PTMSP). The influence of some parameters on the CO2 removal efficiency is explored. A lower removal efficiencies is obtained with a PP-PTMSP fiber compared with Oxyplus® because of a PTMSP layer thickness four times larger than the dense layer of Oxyplus® fibers. Indeed, this dense layer is the key parameter which controls the membrane resistance. Experiments achieved validate the resistance of the membrane to the wettability. Increasing the liquid flow raises the removal efficiency of at least 5%. This one is higher than 90%. In the Oxyplus® module case, similar removal efficiencies are obtained, around 99%, with the blend of methyldiethanolamine and triethylene tetramine (MDEA +TETA) and with monoethanolamine (MEA) for gas velocities lower than 0.84 m⋅s−1. A 363 K regeneration temperature of liquid phase and 2 bar is sufficient to maintain a 90% CO2 removal efficiency.