Simulation of Carbon Dioxide Absorption in a Hollow Fiber Membrane Contactor Under Non-Isothermal Conditions

Area of Science:

• Chemical Engineering
• Environmental Science
• Materials Science

Background:

• Membrane gas absorption is a promising technology for carbon dioxide (CO2) capture.
• The non-isothermal nature of CO2 absorption significantly impacts performance in hollow fiber membrane contactors.
• Understanding these thermal effects is crucial for optimizing CO2 removal efficiency.

Purpose of the Study:

• To evaluate CO2 separation performance using three different absorbents in a polyvinylidene fluoride hollow fiber membrane contactor.
• To investigate the influence of non-isothermal conditions on CO2 absorption.
• To validate a non-isothermal mathematical model against experimental data.

Main Methods:

• Development of a non-isothermal mathematical model for CO2 absorption.
• Two-dimensional computational simulation of the process in a hollow fiber membrane contactor.
• Comparison of simulation results with published experimental data for model validation.

Main Results:

• The mathematical model demonstrated high reliability, with simulation results showing less than 5% deviation from experimental data.
• A significant temperature increase (2–15 K) was observed along the membrane contactor, enhancing absorption and reaction.
• Potassium glycinate showed the highest CO2 absorption capacity, followed by monoethanolamine and 1-ethyl-3-methylimidazolium.

Conclusions:

• The non-isothermal model accurately predicts CO2 separation performance in membrane contactors.
• Potassium glycinate is a superior absorbent for CO2 capture under the studied conditions.
• Optimizing liquid flow rate, absorbent concentration, module length, and membrane porosity enhances CO2 mass transfer.