Utilization of antifoam in biogas plants. Phase I

摘要

The aim was to indicate causes of foaming in biomass conversion plants and to test the effect of a newly developed silicone-based biogas antifoam, 'BG',in preventing and/or stopping such foaming. The causes were found to be the generation of surfactants in the reactor or their presence in the industrial or source-sorted household wastes that were used. A biogas plant at Sindrup (Denmark) was fed daily with 12 cubic meters of pig manure and 300-500 of fish oil waste. Here foaming was due to accelerated degradation of the fish oil wastes which led to the generation of surfactants which aggregated at the slurry-gas interface, lowered the surface tension and so caused foaming. Adding 'BG' antifoam suppressed foaming and successfully dispersed the surfactants resulting in an increase in stable gas production by up to 43%. At the Sinding-Oerre plant, which uses sorted household wastes only, 2-3 liters of 'BG' antifoam added twice weekly prevented foam formation. It was found that the concentration varied from one type of waste to another and the extent of foaming varied at different plants when using this antifoam, so further testing is necessary. The economical effects of using 'BG' were investigated in the case of the biomass conversion plant at Sindrup. (AB)