Equilibrium Behavior of CO2 Adsorption from Biogas onto Zeolites

Abstract

Biogas is one of the types of renewable energy that has a major gas content of CH4 and CO2. One of the methods for upgrading biogas is adsorption. The principle of adsorption’s work is to deliver biogas into a column with containing adsorbent, so that a CO2 gas is bound to zeolite, causing the CH4 to increase in the result product. The biogas used in research came from a cow feces that was dumped into a 10bar pressure vessel. Adsorbent used zeolite 13X that was activated. The biogas tube has a height 0.3 m and diameter 3 cm. It was made of stainless steel and there was a cartridge heater inside. Biogas was channeled into adsorbent column with pressure variations 0.8, 1.2, 1.6 and 2 bars and temperature variations 30, 50 and 100°C. The flow rate of biogas used 4 L/minute with a 4-minute data retrieval. Data retrieval was continuous, so that the composition of CO2 gas from beginning to end recorded on the Gas analyzer. The research aims to identify the balance of adsorption with variations in pressure and temperature by Langmuir equation which has been developed. The results show if the higher the pressure, then CO2 that was absorbed is inversely proportional to the temperature where the higher the temperature, the less CO2 was adsorbed. This research succeeded in getting the Langmuir constant, maximum amount adsorbed of CO2, and heat of adsorption.