The Optimization of Biogas Upgrading: The CO2 Adsorption on Sugarcane Bagasse-Based Biochar and Zeolite

Abstract

Most households in Indonesia use liquefied petroleum gas (LPG) for cooking. Still, the increasing import of LPG is feared to burden Indonesia's current trade balance. Therefore, to meet the demand, it needs other alternative energies. Biogas is a promising alternative energy source for households because it can be produced from agricultural waste or animal manure. Nevertheless, sustainable biogas adoption faces many challenges, including the presence of carbon dioxide (CO₂), which affects the calorific value of biogas. The removal of CO₂ from biogas is known as biogas purification and is often carried out using carbon material (charcoal) as a CO₂ adsorbent.  Carbon-based biomass waste as a CO₂ adsorbent in biogas is an uncommon practice. So far, biomass waste has usually been investigated for biogas upgrading on a laboratory scale using synthetic biogas. This study investigated the use of biomass waste, sugarcane bagasse-based biochar, and natural zeolite, in the different adsorption contact times for increasing the calorific value of biogas by CO₂ adsorption. The CO₂ adsorption was carried out in a biogas purificator in adsorption times of 10, 15, 20, and 25 minutes at room temperature and gas pressure ranging from 6 to 8 bar. The CO₂ adsorption capacity was further reduced by increasing the adsorption time. The combination of sugarcane bagasse-based biochar and zeolite exhibited a high CO₂ removal capacity of 78.49% at 10 minutes of adsorption time. The increase in adsorption time saturated the CO₂ adsorption capacity. The lowest CO₂ adsorption capacity was achieved at 25 minutes of adsorption time with a CO₂ removal capacity of 12.34%.