Efficiency analysis of a biogas plant based on mathematical modeling of mesophilic fermentation processes

The article presents a mathematical model of the biochemical processes occurring in a biogas plant under the mesophilic fermentation regime. The aim of the research was to increase the efficiency of biogas plants by developing mathematical models of biochemical processes. The model is based on a system of differential equations that take into account the dynamics of the key components of the substrate, such as moisture, ash, nitrogen-free extractives (BEV), fats, proteins, and fiber. A number of factors have been identified that may affect the reaction rate, including the temperature regime, the hydrogen index of the reaction medium, as well as the content of ammonia and volatile fatty acids, which exhibit the ability to inhibit. During the calculations, the time dependences of the concentrations of the main components of the substrate were obtained and plotted graphically. As a result, the dependence of the volume output of biogas on the substrate parameters was obtained. The simulation results showed high accuracy in predicting biogas output, especially for piglet manure (R² > 0.96). The model also takes into account the dynamics of microbial biomass and the accumulation of intermediates such as methane and carbon dioxide. The results obtained indicate that the developed mathematical model of the biochemical processes of a biogas plant has high accuracy and can be used to predict the key parameters of anaerobic digestion in the mesophilic regime. The developed approach can be integrated into biogas complex management systems to optimize substrate loading and increase energy generation efficiency. The work prospects include adapting the model to thermophilic conditions and complex substrates.