Thermal effects of CO₂ capture by solid adsorbents:some approaches by IR image processing

Abstract

Thanks to infrared thermography, we have studied the mechanisms of CO₂ captureby solid adsorbents (CO₂ capture via gas adsorption on various types of poroussubstrates) to better understand the physico-chemical mechanisms that controlCO₂-surface interactions. In order to develop in the future an efficientprocess for post-combustion CO₂ capture, it is necessary to quantify the energyof adsorption of the gas on the adsorbent (exothermic process). The released heat (heat ofadsorption) is a key parameter for the choice of materials and for the design of captureprocesses. Infrared thermography is used, at first approach, to detect the temperaturefields on a thin-layer of adsorbent during CO₂ adsorption. An analytical heattransfer model was developed to evaluate the adsorption heat flux and to estimate, via aninverse technique, the heat of adsorption. The main originality of our method is toestimate heat losses directly from the heat generated during the adsorption process. Then,the estimated heat loss is taken for an a posteriori calculation of the adsorption heatflux. Finally, the heat of adsorption may be estimated. The interest in using infraredthermography is also its ability to quickly change the experimental setup, for example, toswitch from the adsorbent thin-layer to the adsorbent bed configuration. We present thefirst results tempting to link the thin-layer data to the propagation speed of the thermalfront in a millifluidics adsorption bed, also observed by IR thermography.