Lab-scale design and fabrication for biogas quality measurement

Biogas is one of the renewable energy sources that may be used as an alternative. It can reduce negative environmental effects by producing electricity from agricultural waste and industrial effluents. This study intends to construct a lab-scale version of the VMMI instrument, which monitors the methane quality inside and outside the laboratory. In addition, this study aims to investigate the biogas upgradation by CO2 capture at atmospheric conditions utilizing three different alkaline absorbents (NaOH, Na2CO3, KOH) in the volumetric meter. To assess the efficiency of these alkaline solutions, an artificial biogas composition with a varied ratio of CO2 from 1 to 95% was prepared using natural gas as a methane source and CO2-filled cylinder. The biogas composition was analyzed on a gas chromatograph before and after CO2 absorption in an alkaline solution. In this study, potassium hydroxide had the maximum CO2 removal, 98%, compared to NaOH and Na2CO3. To further assess the effect of an acidic solvent, 1 M HCl acid was used, but it had a very low CO2 absorbing efficiency of 1.8%. Hence, major findings can help better understand proper alkaline solvent selection that contributes to high CO2 capture efficiency, easy use, and low cost.