Experimental Investigation of Advanced Microscale Reactors for Enhanced Carbon Capture and Natural Gas Sweetening Applications

There is an active need to develop compact mass transfer systems for high efficiency gas-liquid absorption applications, such as solvent-based carbon capture and natural gas sweetening processes. The present paper focuses on the absorption of carbon dioxide in aqueous diethanolamine using microreactors having hydraulic diameters of 762, 508 and 254 μm. The mass transfer phenomenon was studied and characterized with respect to absorption efficiency and mass transfer coefficient. Parametric studies were conducted varying the liquid and gas phase concentrations. Liquid-side volumetric mass transfer coefficients as high as 620 s⁻¹ were achieved, which is between 2–3 orders of magnitude higher than that reported for most conventional gas-liquid absorption systems. High levels of absorption efficiency, close to 100%, were observed under certain operating conditions. The presently observed process intensification was attributed to an increase in the specific interfacial area with reduction in the channel diameter.