A Critical Overview of Development and Innovations in Biogas Upgrading

Abstract

When organic matter decomposes in an anaerobic medium, it produces a gas mixture called biogas. This process is widespred in nature and occurs, for example, in swamps, lake beds, manure, and the rumen of ruminants. Organic material is almost completely converted into biogas by various microorganisms. In addition, certain amounts of energy (heat) and new biomass are produced. The formed gas mixture consists mainly of methane (50–75% by volume) and carbon dioxide (25–50% by volume). Biogas also contains small amounts of hydrogen sulfide, ammonia, siloxanes, nitrogen, oxygen, and moisture. Hydrogen sulfide, the main contaminant, is toxic and emits an unpleasant odor. The vapor contained in the biogas combines with hydrogen sulfide to form sulphuric acid. The acids attack the engines used in the upgrading of biogas, as well as the downstream components such as gas pipes and exhaust systems. Sulfur compounds also reduce the efficiency of downstream processing stages. For these reasons, agricultural biogas plants usually carry out desulphurization and drying of the biogas produced. The production of biogas and biomethane is important for the use of agricultural and industrial wastes and the replacement of non-renewable fossil fuels. This technical paper illustrates the production of biogas as a viable technological alternative to combat climate change and generate renewable energy. Analysis of the costs and applications of biogas is covered in this paper to understand the impact on the environment and world markets.