Geometry effect on membrane absorption for CO₂ capture. Part I: A hybrid modeling approach

Abstract

Membrane absorption (MA) has a great prospect for CO2 capture. In MA modeling, conventional one‐dimensional (1D)‐ and two‐dimensional (2D)‐models make simplification of membrane contactor (MC) geometry. Geometry simplification allows an easy process modeling and numerical solution, however, is only reasonable for particular MCs. Here, efforts are underway to quantify the geometry effect on the MA‐CO2 performance. First, we proposed a rigorous 3D model without geometry simplification for simulating the MA‐CO2 process in real MCs and then validated it with experimental data. More importantly, we highlighted a preferable hybrid model in which two correction factors were introduced to a 2D model to make the simulation results approximately equal to the 3D simulation values. The correction factors were correlated with dimensionless fluid dynamic parameters for characterizing the geometry effects on flowing fluids. Such hybrid modeling contributes to characterizing the influence of geometry on the MA‐CO2 performance and improving computation accuracy‐efficiency combinations.

3D models guide the design of hollow fiber membrane contactors with complex internal structures for CO2 capture

“…It can be seen that no matter how many tubes there are, the liquid always shows a steady laminar flow. This result is somewhat different from the simulation results of Fu et al 17 on the velocity field in the membrane contactor. This is because they used a membrane contactor with a very low H/D ratio resulting in membrane fibers that are located near the center region to have higher velocity than those position close to the outer edges.…”

“…The results show that the relationship between the outlet concentration and the fiber number is not linearly proportional, and the increase of fibers provides a high contact area and promotes mass transfer. Fu et al 17 established a hybrid model to explore the mass transfer performance of MEA in membrane contactor uptake CO 2 , and the results showed that the number of membrane fibers had a great influence on the flow distribution. This shows that models that consider only a single membrane deviate significantly from the actual results.…”