Determination of adsorption capacities of N₂ and CO₂ on commercial activated carbon and adsorption isotherm models

¹ Gazi University, Faculty of Engineering, Chemical Engineering Department, 06570 Maltepe, Ankara, Turkey
² Gazi University, Graduate School of Natural and Applied Sciences, 06500 Teknikokullar, Ankara, Turkey

^* Corresponding author: hazaloztan@gazi.edu.tr

Abstract

In today’s technologies of gas purification systems, adsorption processes offer more advantages than traditional processes (amine absorption and cryogenic distillation). Thanks to advantages such as high efficiency, low energy consumption and ease of operation, the adsorption process plays an important role in today’s natural gas purification and carbon capturing processes. In order to bring natural gas to the usage standards and to ensure carbon capture in the emission sources (coal mines, landfills, agricultural activities, etc.) that emit CO₂-CH₄ as a result of human activities, it is extremely important to purify impurities such as CO₂ and N₂, which are highly present in the gas mixture. In the study, the adsorption of N₂ and CO₂ gases on activated carbon and the effect of pressure and temperature on adsorption were examined. The operating conditions pressure range was 1-6 bar and temperatures below room temperature. Experimental studies were carried out in laboratory scale adsorption cell system. As a result of the studies, it was determined that the adsorption capacity of activated carbon N₂ and CO₂ increased with pressure. N₂ adsorption capacities were determined between 0.4-7.8 mmol/g and CO₂ adsorption capacities were determined in the range of 2.7-7.4 mmol/g. In addition, Langmuir and Freundlich isotherm models were created, model parameters were examined and the adsorption behaviour of activated carbon for CO₂ and N₂ gases was obtained.