Biogas Purification Using Natural Zeolite and NaOH

Abstract

Biogas purification is the most important process for improving the quality of biogas. This research introduced a continuous system for purifying biogas from CO₂ impurities using zeolite and a NaOH solution. The granular zeolites were arranged in 1 to 5 layers on a solid purifier. The concentration of the NaOH solution was varied from 10 per cent to 50 per cent. The contact time between the biogas and the zeolite and NaOH solution was monitored at 15-minute intervals. The results showed that the NaOH solution absorbed CO₂ more rapidly than the zeolite. In the initial minutes, the NaOH solution at the same concentration absorbed CO₂ until less than 10 per cent of the CO₂ volume in the biogas remained. Furthermore, the five layers of zeolite were able to adsorb CO₂ until 21.3 per cent of the CO₂ volume in the biogas remained after 60 minutes. Under similar conditions, CH₄ levels rose to 74.7 per cent and 92.4 per cent for the zeolite and NaOH solution, respectively. The CO₂ absorption capacity was influenced by the number of layers in the zeolite purification system and the concentration of the NaOH solution in the NaOH purification system.

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