ADSORPTION - DESORPTION SYSTEM FOR CO2 REMOVAL IN BIOGAS USING NATURAL ZEOLITE - BASED ADSORBENT

Abstract

This study aimed to remove CO2 from air-CO2 mixture using natural zeolitebased adsorbent pellets through adsorption and to regenerate the adsorbents using air through desorption. The experiment was conducted to determine the percentage of CO2 removal and breakthrough curve characteristics by varying the flow rate of the air-CO2 mixture and the type of adsorbent pellet. The residual CO2 content of purified gas was analysed every minute and stored in the gas collector. Pure air with ambient temperature ranging from 30 to 40 °C flowed through a column for desorption of CO2 in the saturated pellet adsorbent. Results concluded that the best percentage of CO2 removal was 92.5% by using adsorbent pellet with particle size of 140 mesh, calcination temperature 400 °C for four hours and a flow rate of mixed gas at 200 ml/min. This characteristic also described the optimum CO2 desorption that is achieved at 40 °C of air temperature and flow rate of 200 ml/min for 20 minutes. The adsorption equilibrium was fitted using Langmuir isotherm with R2 correlation value of 0.9962. Modelling of adsorption kinetics to describe breakthrough curve used pseudo-order and Elovich kinetics. The results showed that the pseudo-order kinetics provided good results under operating conditions.

Keywords

• Adsorption
• Biogas
• Carbon dioxide
• Desorption
• Zeolite