Electroactive tube arrays of diatomaceous silica-filled biocarbon for CO2 separation through electric swing adsorption

Abstract

Electroactive biocarbon tubes filled up with diatomaceous earth pellets were set up in a tube array for the CO2 separation through an Electric Swing Adsorption (ESA) cycle. The tube array was self-heated by applying voltage between its ends. The direct heating of the adsorbent material sped up the desorption step and thus quickly releasing an enriched CO2 gas phase. The dynamics of the tube array’s temperature and the CO2 molar fraction in the gas phase adsorbent showed consistency when consecutive ESA cycles were performed. In order to define the conceptual design of the ESA cycle, the CO2 competitive adsorption capacities were estimated for a set of CO2/N2 gas mixtures (≤10% CO2). The tubular adsorbent array essentially maintained its performance and structure when tested in the presence of air. The hybrid tube array demonstrated repeatability and stability for CO2 separation through consecutive ESA cycles. The tube array configuration is advantageous in terms of the process scale-up and modular chemical process intensification in the agroindustry.