Biogas Plant CE 642
In a biogas plant, microorganisms biologically decompose the organic starting substances (substrate) under exclusion of light and oxygen.
The product of this anaerobic decomposition is a gas mixture which primarily consists of methane. This gas mixture is called biogas. The biogas produced can now be combusted in a combined heat and power plant. This converts the energy stored in the biogas to rotational energy. A connected generator then converts this rotational energy into electric power.
In addition to electrical energy, a combined heat and power plant also produces heat which can, for example, be used to heat the reactor or buildings.
The complex processes of anaerobic decomposition can be simplified as four consecutive phases.
Phase 1: Hydrolysis
The substrate used in biogas plants is available as undissolved, high-molecular compounds such as proteins, fats and carbohydrates. Therefore these compounds first have to be broken down into their individual components. Hydrolysis products are amino acids, sugars and fatty acids.
Phase 3: Formation of acetic acid
The products of the previous phase are now converted into acetic acid, hydrogen and carbon dioxide.