Current aspects such as the constant strengthening of legal emission requirements and the need for energetic optimisation require an innovative further development of biogas purification, especially the removal of hydrogen sulphide (H2S). The use of a biological-oxidative cleaning process represents a sustainable holistic approach to biogas desulphurisation.
Objectives of the Project
To reduce the H2S content of biogas, the NitroSX project is investigating a new microbiological desulphurisation process. Here, the focus is laid on an alternative respiratory chain for biotechnological hydrogen sulphide oxidation on EvU Pearl® material. Moreover, the establishment of an automated process control is targeted. During this desulphurisation process particularly nitrate (NO3-) can be used as electron acceptor, which has the advantage that it can be added without high energy input or is already present in the medium.
Within the project, a pilot plant will be designed and built on a container scale, which will then be tested in agricultural biogas plants. The plant will be operated with digestate and biogas from a biogas plant to ensure realistic and practical operating conditions. The naturally occurring micro-organisms (chemolithotrophic bacteria) and the nutrients in the digestate convert reduced sulphur compounds to produce energy. In biological desulphurisation, these strains are used to decompose H2S in the biogas with nitrate (NO3-). The conversion takes place in stages from elemental sulphur to sulphate.
Description of the Process Principle
The pilot plant consists of a biogas countercurrent adsorption column with connected Moving-Bed-Bio-Reactor (MBBR) to validate the general conditions for process engineering. The test plant incl. measurement, control and regulation technology is manufactured in a compact container design.