Development of a membrane dispersion micro-absorber for CO2 capture

In this paper, a micro-absorber has been developed to indensify the CO2 capture process, with a 5 μm pore size microfiltration membrane as the dispersion medium to enhance mass transfer by realizing gas–liquid microflows. The new absorber's performance was evaluated using five different working systems. The effects of flow rates on bubble size and mass transfer characteristics were studied. The bubble size ranges from 20 to 100 μm. Murphree efficiency can reach nearly 100% and the residence time is less than 2 s. The volumetric mass transfer coefficient, KLa, is found to range in 35–130 s−1, which is 3 orders of magnitude larger than the values reported for conventional absorbers. The device shows very good flexibility of operation and very low energy cost. With the change of capacity from 160 mL/cm2 s to 1000 mL/cm2 s the device can keep Murphee efficiency higher than 90%, and the transmembrane pressure is lower than 10 kPa. This absorber will potentially provide method for CO2 capture with broad applicability, high efficiency, low input energy and large capacity.

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► We develop a micro-absorber to indensify the CO2 capture process.
► 5 μm pore size microfiltration membrane as the dispersion medium.
► Murphree efficiency can reach nearly 100% when residence time is less than 2 s.
► KLa ranged in 35–130 s−1 and capacity up to 1000 mL/cm2 s.
► Broad applicability, high efficiency, low input energy and large capacity.