(186d) A Novel Membrane-Based Technology for Post-Combustion CO2 Capture and Recovery

Conventional method for CO₂ capture from post-combustion flue gas generally employs  an absorption and stripping process. The CO₂ is absorbed for example in an aqueous solution of amine e.g., monoethanolamine and then stripped out in a separate tower with steam at 120⁰C. Such a process is highly energy intensive. Further the amine used is volatile. The low partial pressure of CO₂ in the flue gas inhibits the application of CO₂-selective membranes unless methods are employed to increase the CO₂ partial pressure in the flue gas to be treated. Adsorption processes relying on adsorbent regeneration require among others the need to switch the flue gas between different columns. A number of other techniques are being studied to reduce the capital and operating costs for CO₂ capture from post-combustion flue gas. We will describe a novel membrane-based technique to potentially bypass most of the shortcomings of many existing approaches. We have employed a simulated humidified flue gas containing around 14% CO₂ and demonstrated successful removal of bulk of the CO₂ and its recovery in a CO₂-concentrated stream. We have characterized the performance of the membrane-based device used. We will deliberate on the strengths and weaknesses of this technology.