Performance assessment of natural base ash solutions for removal of hydrogen sulfide from raw biogas

Setting up of decentralized biogas plants in rural areas can be an effective solution to mitigate growing energy demands among the rural community. Biogas produced from anaerobic digestion of organic matter is mainly composed of methane and carbon dioxide along with other trace components like hydrogen sulphide, carbon monoxide and nitrogen. Removal of H₂S from biogas is essential to prevent corrosion of the gas stoves and also to reduce air pollution. This study reports a low cost, easy to operate, portable biogas purification system that utilizes natural base ash solutions to remove H₂S from raw biogas by absorption process. Banana is reported to be the second largest produced fruit, accounting for 16% of the total fruit production worldwide, and simultaneously generates a lot of waste biomass. In this study, performance assessment of ash solutions prepared from solid waste banana peels and pseudostem as a scrubbing agent for the removal of H2S from raw biogas is reported. The absorption scrubber, filled with natural base ash solutions prepared from Musa balbisiana peel effectively removes 88.03% H2S from raw biogas followed by Musa acuminata peel ash solution (85.27%) and banana pseudostem ash solution (80.98%). The absorption of H₂S by all the natural base ash solutions is provisional and has to be refilled after reaching saturation period. The biomass availability, easy preparation method and environment-friendly nature of this natural base solution renders it as a potential candidate for rural applications.