Experimental investigation on the desorption of CO2 enriched liquids based on ceramic membranes

The waste heat utilization in the coal-fired plant has always been one of important ways of the energy saving. In this paper, a novel device is constructed by the combination of the ceramic membrane desorption and the flue gas waste heat utilization. In the device, the absorption solution is the “double-cationic” ionic liquid ([TEPA][1-MIm]). Furthermore, experimental results show that the contact angle of the hydrophobic ceramic membrane is 130°. Under ambient temperature conditions, it is observed that at a concentration of 25 % [TEPA][1-MIm] in an ethylene glycol solution, the maximum absorption amount of CO₂ reaches approximately 1.605 mol CO₂/mol amine. The saturation time of the absorption is about 20 min. As the concentration of ionic liquids increases, the saturation time gradually extends due to an increase in [TEPA][1-MIm] and consequently higher total CO₂ absorption mass. Subsequently, effects of the operating parameters on the desorption rates are analyzed. The contribution of this work is to put forward the idea of utilizing ceramic membranes to recover the waste heat from the flue gas to reduce the CO₂ desorption energy consumption. According to experiments, the overall heat transfer coefficient can reach 20.33 W/(m²·K), and the amount of the recovered waste heat can reach 29.97 W.