Modeling and Optimal Operating Conditions of Hollow Fiber Membrane for CO₂/CH₄ Separation.

Area of Science:

• Chemical Engineering
• Materials Science
• Environmental Science

Background:

• Carbon dioxide (CO2) emissions pose environmental challenges, necessitating efficient capture technologies.
• Dense hollow fiber membranes (HFM) offer a promising approach for gas separation and carbon capture.
• Understanding the factors influencing CO2 flux and recovery is crucial for optimizing membrane performance.

Purpose of the Study:

• To experimentally and theoretically investigate carbon dioxide capture using dense hollow fiber membranes.
• To study the effects of CO2 concentration, feed pressure, and temperature on CO2 flux and recovery.
• To develop and validate a comprehensive model for predicting CO2 flux through the membrane.

Main Methods:

• Lab-scale experiments using a methane-CO2 mixture to simulate natural gas.
• Parametric study varying CO2 concentration (2-10 mol%), feed pressure (2.5-7.5 bar), and temperature (20-40 °C).
• Development of a comprehensive model based on the solution-diffusion mechanism and Dual sorption model, utilizing CFD techniques (COMSOL 5.6) for simulation.

Main Results:

• CO2 flux and recovery are significantly influenced by feed pressure and CO2 concentration.
• Temperature directly affects gas diffusivity and mass transfer coefficient, while pressure has an inverse effect.
• Optimal operating conditions (7.5 bar, 30 °C, 10 mol% CO2) yielded a CO2 recovery of 30.3%.

Conclusions:

• The developed model accurately predicts CO2 flux, showing good agreement with experimental data.
• Operational parameters significantly impact the efficiency of CO2 capture via hollow fiber membranes.
• The findings provide valuable insights for the feasibility studies and economic evaluation of industrial gas separation units.