CFD investigation of CO2 absorption/desorption by a fluidized bed of micro-encapsulated solvents

• Main Authors: Justin R. Finn, Janine E. Galvin, Katherine Hornbostel
• Format: Article
• Language: English
• Published: Elsevier 2020-02-01
• Series: Chemical Engineering Science: X
• Online Access: http://www.sciencedirect.com/science/article/pii/S2590140019300577

Micro-encapsulated solvents (MECS) have been proposed for flue gas CO2 capture. However, relatively little is known about the collective behavior of MECS in fixed or fluidized beds. Therefore, we extended our model for microcapsule CO2 capture (Finn and Galvin, 2018) to a CFD-DEM framework. Temperature and CO2 absorption measurements for microcapsules with catalyzed, aqueous, sodium carbonate solution in a small (order 20 g) bed were used for validation. The influence of inlet gas temperature, relative humidity, and gas flow rate on absorber/regenerator performance was explored. The bed averaged CO2 mass transfer rates were largely insensitive to inlet gas velocity over the time considered. The direction and magnitude of capsule water flux was very sensitive to changes in inlet gas temperature/relative humidity. Precise control of temperature/humidity may be needed if sodium carbonate capsules are to be deployed in fixed/fluidized beds at larger scales. Keywords: Micro-encapsulated solvents (MECS), Post-combustion carbon capture, Fluidized bed absorber, Sodium carbonate carbon capture