CO2 removal by single and mixed amines in a hollow‐fiber membrane module—investigation of contactor performance

Abstract

This work investigates CO2 removal by single and blended amines in a hollow‐fiber membrane contactor (HFMC) under gas‐filled and partially liquid‐filled membrane pores conditions via a two‐scale, nonisothermal, steady‐state model accounting for CO2 diffusion in gas‐filled pores, CO2 and amines diffusion/reaction within liquid‐filled pores and CO2 and amines diffusion/reaction in liquid boundary layer. Model predictions were compared with CO2 absorption data under various experimental conditions. The model was used to analyze the effects of liquid and gas velocity, CO2 partial pressure, single (primary, secondary, tertiary, and sterically hindered alkanolamines) and mixed amines solution type, membrane wetting, and cocurrent/countercurrent flow orientation on the HFMC performance. An insignificant difference between the absorption in cocurrent and countercurrent flow was observed in this study. The membrane wetting decreases significantly the performance of hollow‐fiber membrane module. The nonisothermal simulations reveal that the hollow‐fiber membrane module operation can be considered as nearly isothermal. © 2014 American Institute of Chemical Engineers AIChE J, 61: 955–971, 2015