Modeling CO2 separation on amine-containing facilitated transport membranes (AFTMs) by linking effects of relative humidity, temperature, and pressure

Abstract

Amine-containing facilitated transport membranes (AFTMs) hold great potential in CO2 separation and show remarkable separation performance under the existence of water. Conventional membrane gas separation models that mainly consider the effect of temperature and pressure are less effective for modeling AFTMs. In this study, we present a model that involves variable CO2 permeance in AFTMs concerning relative humidity (RH), temperature, and CO2 partial pressure. Sensitivity analysis and comparison of the proposed model and simplistic model highlight the significance of considering the effect of RH and CO2 partial pressure on gas permeance of AFTMs. Case study results of post-combustion carbon capture indicate that variations in CO2 concentration and feed pressure bring more pronounced changes on the separation performance of AFTMs than in temperature. Besides, the results of RH along the membrane module provide evidence of membrane area for module design with required RH, and the results can also be used to guide the humidification of multistage separation processes using AFTMs. Overall, the proposed model can be integrated into commercial process simulators to study the separation process with consideration of variations in operating conditions within the membrane module, overcoming the lack of rigorous models for supporting the design of membrane systems for carbon capture.