Numerical solutions to the Reactive Graetz Problem for CO2 Capture

Abstract

Hollow Fiber Membrane Contactor Modules comprise a technology that is considered promising for mobile carbon capture due to its high surface area per unit volume and low pressure drop. Although experimental, theoretical, and numerical studies have been devoted to understanding and improving performance, no study has so far used numerical simulations to show how the system scales with flow rate, reactivity, solubility, etc. in full generality. The present study addresses this scaling by solving the so called reactive Graetz problem: a canonical partial differential equation system coupling gas and liquid flow domains, including solubility and reactivity effects unlike the original Graetz problem. It is found that the Peclet number of the liquid, the aspect ratio of the fiber, and the Damkohler number of the liquid solvent, all play decisive roles in the mass transfer of CO2 and the work exerted per molecule captured.