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

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.

Keywords

• adsorption
• activated carbon
• coal bed methane
• psa
• adsorption isotherms