DefinePK

Abstract

This article presents the design and implementation of an experimental biogas plant, which consists of a digester with a useful volume of 30 l and a wet gas tank. The main contribution of this work is the provision of a new tool in the field of biogas production by controlling the loading of the substrate into the digester. The substrate is prepared by mixing a measured amount of cattle manure with water and a vegetable oil sediment. As a result of the experimental study, it was established that the rational cycle of the fermentation of cattle manure is 13-14 days, a mixture of cattle manure and orhanat - 9-10 days. Biogas output increases with increasing fermentation temperature. For 14 days of fermentation, the average accumulated output of biogas during the fermentation of cattle manure at a fermentation temperature of 55 °C is 336 l/kg of dry organic matter (DOM), at a fermentation temperature of 50 °C is 283 l/kg DOM, 45 °C is 257 l/kg DOM, 40 °C is 184 l/kg DOM. Cattle manure after feeding livestock with silage and concentrated feed generates a slightly higher output of biogas compared to cattle manure after feeding livestock with straw based feed. The total volume of biogas obtained during the fermentation of the mixture of cattle manure and orhanat is higher than when the pure cattle manure is fermented. At the same time, a unit of DOM of pure cattle manure gives a greater output of biogas compared with a unit of DOM of a mixture of cattle manure and orhanat. When fermenting a mixture of cattle manure and orhanat at a temperature of 45 °C, it turns out 195.7 l/kg DOM of biogas, 45 °C - 175.7 l/kg DOM of biogas. The average calorific value of biogas obtained during the fermentation of cattle manure is in the range of 12-17 MJ/m3. The biogas obtained during the fermentation of a mixture of cattle manure and orhanat does not burn at all at the initial stage of fermentation (2-5 days). In the next few days, the burning of biogas is very weak. At the same time in atmosphere of the laboratory room, there is a persistent smell of hydrogen sulfide. Subsequently, combustion is normalized and the calorific value of biogas approaches standard values.