Capture and Recovery of Isobutane by Electrothermal Swing Adsorption with Post-Desorption Liquefaction

A bench-scale capture and recovery system to convert a low concentration organic gas to a liquid is described here. Adsorption of isobutane onto activated carbon fiber cloth (ACFC) followed by electrothermal desorption and subsequent liquefaction is demonstrated. Experimental conditions to condense desorbed isobutane were determined based on Dalton’s law and Antoine’s equation. Breakthrough curves for a gas stream containing 2000 ppmv isobutane in air adsorbing onto ACFC-15 demonstrate an adsorption capacity of 0.094 ± 0.017 g of isobutane/g of ACFC with >98% capture efficiency. The system described here utilizes two adsorbers, which operate cyclically to allow for continuous treatment of the isobutane. Adsorption followed by electrothermal desorption provided a concentration ratio of 240, which facilitates condensation of the isobutane after compression and cooling and is an order of magnitude greater than what has been previously demonstrated.