Parametric Study of Biogas Upgrading Process Using Thermal Swing Adsorption Technique

The thermal swing adsorption process has been demonstrated as a promising technology for the biogas upgrading process, with ease of integration into renewable electricity sources. This study examined the influence of particle radius, regeneration temperature, and purge-to-feed flow rate ratio on the biogas upgrading process. A dynamic simulation model was developed to study the carbon dioxide capture process. Activated carbon pellets derived from coconut shells were used as the adsorbent material. The adsorption and desorption processes were based on single-component methane and carbon dioxide adsorption isotherms fitted to the Langmuir-Freundlich model. The developed simulation model was validated against experimental data. A particle radius, regeneration temperature, and purge-to-feed flow rate ratio range of 1 to 9 mm, 77 to 227 °C, and 0.1 to 0.7, respectively, were adopted for the parametric analysis. Multi-objective numerical optimization was performed using the response surface methodology. The results indicated that the purge-to-feed flow rate ratio had the highest contribution to the methane purity and recovery models of 92.37 % and 99.90 %, respectively. The optimal methane purity and recovery values obtained were 82.12 % and 37.21 %, respectively, achieved at a particle radius of 9 mm, a regenerating temperature of 227 °C and a purge-to-feed flow rate ratio of 0.4152.