CO2 Capture on an Adsorbent-Coated Finned Tube Heat Exchanger: Effect of the Adsorbent Thickness

The reduction of cycle time is crucial to obtain viable adsorptive CO2 capture processes. In thermal swing adsorption processes, heating and cooling of the adsorbent result in long cycle times. In the present paper, the adsorbent was coated on a finned heat exchanger tube to reduce the heating and cooling times. The effect of the adsorbent/exchanger mass ratio on the regeneration time and energy efficiency of CO(2 )adsorption and desorption were investigated. To do so, finned tubes were coated by three different masses of 13X powder and were used in an indirect-heating system for CO2 sorption. Increasing the loaded adsorbent mass density from 58.5 to 215.7 g/m(2) did not affect the CO2 sorption rate. This is because of the short characteristic time of heat diffusion due to the limited spacing between the adjacent fins. Energy analysis of the system shows that the energy consumed per mole of desorbed CO2 decreases with increasing adsorbent mass. The maximum energy efficiency is less than 3%.