Performance improvement of water and heat recovery from stripped gas in a carbon capture process: Assembling different pore-sized ceramic membranes in a transport membrane condenser

Abstract

Recently, the transport membrane condenser (TMC) has demonstrated remarkable performance in recovering waste heat and condensate from hot and moist gases streams by simultaneous mass and heat transfer capabilities. Notably, in the solvent-based CO₂ chemical absorption process, TMC has also experimentally shown a good energy-saving potential through acting as the heat exchange medium between the hot stripped gas (i.e., the gas mixture of CO₂ and water vapor) and bypassed cold CO₂-rich solvent to drive an enhancement of waste heat recovery. In this work, a novel TMC structure was proposed by assembling ceramic membranes with different pore sizes to further improve the energy-saving potential. Ceramic membranes with pore sizes of 30 nm and 100 nm were initially selected for constructing the TMC due to their superior waste heat recovery performance. Subsequently, eight ceramic membranes with 30 nm and 100 nm pore sizes were encapsulated within a shell to assemble the TMC, and then its energy-saving potential was experimentally investigated, focusing on waste heat recovery performance. Results showed, among the five investigated TMC structures, where the stripped gas first contacted 100 nm membranes followed by 30 nm membranes demonstrated superior energy-saving potential in which the area ratio of 100 nm–30 nm membranes was maintained at 1:1 to 1:3. Notably, at a 1:1 area ratio, the TMC with 100 nm spaced by 30 nm membrane layout was achieved a maximum energy-saving potential of 0.94 MJ/kg-CO₂, representing a 13.2 % increase over TMCs using only 30 nm membranes. Current finding offers a promising new direction for TMC structural design.