Hollow fiber membrane contactors for post-combustion CO2 capture: a scale-up study from laboratory to pilot plant

Membrane contactors have been proposed for decades as a way to achieve intensified mass transfer processes. Post-combustion CO2 capture by absorption into a chemical solvent is one of the currently most intensively investigated topics in this area. Numerous studies have already been reported, unfortunately almost systematically on small, laboratory scale, modules. Given the level of flue gas flow rates which have to be treated for carbon capture applications, a consistent scale-up methodology is obviously needed for a rigorous engineering design. In this study, the possibilities and limitations of scale-up strategies for membrane contactors have been explored and will be discussed. Experiments (CO2 absorption from a gas mixture in a 30%wt MEA aqueous solution) have been performed both on mini-modules and at pilot-scale (10 m2 membrane contactor module) based on PTFE hollow fibers. The results have been modeled utilizing a resistance in series approach. The only adjustable parameter is in fitting the simulations to experimental data is the membrane mass transfer coefficient (km), which logically plays a key role. The difficulties and uncertainties associated with scaleup computations from lab scale to pilot-scale modules, with a particular emphasis on the km value, are presented and critically discussed.