A techno-economic analysis was completed to compare the use of Hollow Fiber Membrane Modules (HFMM) with the more conventional structured packing columns as the absorber in amine-based CO₂capture systems for power plants. In order to simulate the operation of industrial scale HFMMsystems, a two-dimensional model was developed and validated based on results of a laboratory scale HFMM. After successful experiments and validation of the model, a pilot scaleHFMMwas constructed and simulated with the same model. The results of the simulations, from both sizes of HFMM, were used to assess the feasibility of further up-scaling to a HFMM system to capture the CO₂from an 800 MWe power plant. The system requirements – membrane fiber length, total contact surface area, and module volume – were determined from simulations and used for an economic comparison with structured packing columns. Results showed that a significant cost reduction of at least 50% is required to make HFMM competitive with structured packing columns. Several factors for the design of industrial scale HFMMrequire further investigation, such as the optimal aspect ratio (module length/diameter), membrane lifetime, and casing material and shape, in addition to the need to reduce the overall cost. However,HFMMwere also shown to have the advantages of having a higher contact surface area per unit volume and modular scale-up, key factors for applications requiring limited footprints or flexibility in configuration.

Membrane contactors have been proposed for decades as a way to achieve intensified mass transfer processes. Post-combustion CO₂capture 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 (CO₂absorption 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.