Before the biogas can be utilized, it is essential to remove the sulphur compounds, which are mainly present in the biogas as sulphide (H2S). Sulphur can cause severe corrosion in boilers and engines utilizing biogas. Sulphur is an essential nutrient for living organisms, and is found for instance in proteins. During the production of biogas, the sulphur is converted biologically to H2S. Biological processes can also be used to remove the H2S from the biogas.
The system is environmentally safe, has minimal power requirements and has a clogging free scrubber which needs almost no maintenance. The process operates at ambient temperature and pressure, and requires almost no chemicals since only the chemicals lost in the small sulphur bleed stream have to be replaced. The recovered sulphur can easily be disposed for sulphuric acid production or as a fertiliser.
Features and benefits
- Deep H₂S removal efficiency
- No addition of air (N2, CO2 and O2) to biogas stream, therefore very suitable for further biogas upgrading without changing clean biogas flow and composition
- Small footprint
- Most reliable and robust H2S removal process, applicable to high turn down ratios and S-load fluctuations.
- Very fast and stable start-up procedure with small biomass inoculum
- Significant chemical savings (caustic, active carbon, iron ore) leading to much lower operating cost.
- No risk of clogging in the scrubber column