OPTIMISING BIOLOGICAL DESULPHURISATION OF BIOGAS BY ADDITION OF HUMIC SUBSTANCES

摘要

This paper presents a possible optimisation of biological desulphurisation of biogas with the addition of humic substances. The idea of the optimisation is the addition of solubilisers (humic substances in this instance) into the washing liquid in order to achieve an upgrade of the absorption of hydrogen sulphide (H2S). The whole process consists of a bioscrubber and a downstream bioreactor. In the bioscrubber the absorption is improved by the addition of humic substances. The downstream bioreactor acts as a regenerator of the washing liquid. An additional aim in this investigation is to obtain elemental sulphur which can be used e. g. as fertiliser in agriculture. In laboratory experiments the efficiency of humates as solubilisers for the absorption of H2S, as well as their suitability for the application in the bioscrubber, were investigated. In steady state experiments the optimising of absorption was carried out. These experiments showed that the humic substances “Humin-P” (potassium humate) and “Humin-S” (sodium humate) achieved significant improvements in comparison to pure water as washing liquid. In two laboratory bioreactors the regeneration of humic substances as well as their effect on the sulphur bacteria, Thiobazilli, was investigated. Humic substances have characteristics like hardly biological degradable and non-toxic which recommend their application in this system. The laboratory experiments show that the use of humates in the biogas treatment is effective. The desulphurisation is simplified by the increased solubility of H2S in humate solutions. In a pilot plant at a biogas power station site the efficiency of this treatment will be tested.