A review of low-cost materials for biogas purification

Abstract

The increasing demand for energy for both household and industrial use has necessitated the exploration of renewable energy sources such as biogas. Raw biogas contains 50–70% methane and impurities which comprise 30–40% carbon dioxide, 5% moisture, 0.5% hydrogen sulfide, and other trace compounds. In Kenya, biogas is used in households without purification. This poses challenges such as corrosion of equipment and low biogas calorific value. In this study, we assess the various low-cost adsorbents that have been recently employed for biogas purification. The materials evaluated include activated carbon from organic waste such as coconut shells, and iron oxide from lathe machine iron chips. The performance of these materials in biogas purification that has been reported in various studies is evaluated. The findings indicate that these materials have great potential in biogas purification and can be readily applied in small-scale systems. Such systems are expected to contribute significantly to increase the access to clean energy in rural areas.