Optimization of Biogas Purification Employing High-Pressure Water Scrubbing

Purification of biogas is the pre-requisite of the commercial application of anaerobic digestion in the renewable energy sector. In this study, Aspen Plus V11.1 was used to determine the optimum process conditions for biogas purification using high-pressure water scrubbing. The non-random two-liquid model (NRTL) coupled with Henry ' s law was used as the fluid package in this study. According to henry ' s law solubility of CO2 is higher than CH4 and thus water was used as an adsorbent. The ideal parameter values for the scrubber were as follows: water pressure: 8 atm, biogas temperature: 37°C or 55°C, scrubber stages: 15, water to biogas mass flowrate ratio: 50. The composition of the biogas i. e., CH4 and CO2 mole fractions can vary in a wide range without effecting the efficiency of the process.