Energy production using organic waste and renewable energy sources is becoming increasingly important. The production of biogas is under anaerobic conditions by fermentation of biomass. In this process, energy-bearing methane gas and various by-products are formed depending on the substrate layer. The by-products, such as hydrogen sulphide, ammonia, but also siloxanes, not only interfere with methanogenesis, but above all they are deposited in the gas engine, increase the number of oil changes and in the worst case it can lead to engine failure.
Tone of the most commonly used biogas desulphurisation is activated charcoal impregnated with potassium iodide, which additionally binds ammonia.
During the processes hydrogen sulphide and mercaptans are converted to elementary sulphur or disulphides by a catalytic oxidisation process within their pore structure.
This requires the presence of twice as much stoichiometric amount of oxygen, the preferred temperatures between 10 and 70 ° C.
Organic silicon compounds, so-called siloxanes, are more common in substrates such as used fats and waste materials that are used as coferments.
During the combustion of siloxanes, a fine crystalline silica is produced, e.g. in engines on cylinders and pistons and it can lead to damaging them.
With the aid of activated carbon, the last residues of the inhibitory substances are also filtered out, and the biogas is well prepared for the next processes.