Aqueous Morpholine As a Potential Post-Combustion CO2 Absorption Solution

Due primarily to high cyclic capacity and high absorption rates compared to other methods, aqueous amine based CO₂ capture has gained great interest for application to post-combustion CO₂ capture. While aqueous amines have a long history for acid gas removal, challenges remain for the commercial application to power plant post-combustion CO₂ capture due to the high gas volume and low CO₂ gas pressure. These challenges require a solvent able to simultaneously deliver high mass transfer rate, high thermal and oxidative stability, low corrosion, and low energy of solvent regeneration to effectively reduce the cost of post-combustion CO₂ capture.  Morpholine was identified to potentially meet the above needs. The absorption of carbon dioxide into aqueous morpholine solutions (35-53 wt%) using a wetted wall column were performed using simulated flue gas at atmospheric pressure and with 3-14 vol% of CO₂ to obtain the overall mass transfer coefficient. Temperatures between 30-40 °C were tested as a believed reasonable compromise between acceptable absorber tower temperatures and morpholine volatility.