A multi-stage biogas plant with a hydrolysis stage consists of several tanks in which organic materials are fermented under anaerobic conditions to produce biogas. The hydrolysis stage is the first stage of the process in which the starting material is broken down by enzymes into smaller molecules such as sugars, fatty acids and amino acids.
One other stage is the receiving pit, where the feedstock such as liquid manure, manure, organic waste or energy crops is stored. In this phase, the material is crushed and homogenized to allow for better mixing and more effective fermentation.
The next stage is the hydrolysis stage, where the homogenized material is hydrolyzed in one or more tanks. At this stage, enzymes are added that break down the organic materials and break them down into smaller molecules that are more readily available for fermentation by bacteria. This stage increases the effectiveness of biogas production and speeds up the fermentation process.
The third stage is the fermentation stage, in which the hydrolyzed material is fermented in one or more fermenters under anaerobic conditions. The material is broken down by anaerobic bacteria and converted into biogas. This stage can also be divided into multiple stages to increase the efficiency of biogas production.
The final stage is biogas upgrading, where the biogas produced is cleaned and upgraded for use as fuel or for other purposes such as power generation or feed into the gas network.
A multi-stage biogas plant can be equipped with various additional components such as fat separators, drying or separation systems, heat exchangers and digestate storage systems, depending on requirements and the materials used, in order to optimize the process and achieve greater efficiency.