DETERMINATION OF ENERGY EFFICIENT LEVEL OF THE SPEED OF MIXING BODY OF ELECTROMECHANICAL SYSTEM

Abstract

Purpose. Today, biomass fermentation in biogas plants is one of the most advanced, environmentally and economically viable solutions for energy production from waste. However, the process of anaerobic digestion of waste is long, so the main process of intensification is mixing. Analysis of well-known studies of domestic and foreign scientists indicates the urgency of reducing energy consumption for the mixing process. The aim of the study is to determine the energy-efficient speed of a paddle stirrer with blades set at an angle of 450 for small biogas reactors. Methodology. At the decision of the set tasks the general methods of physics, three-dimensional modeling, processing and visualization of the received results in the SolidWorks Flow Simulation and Wolfram Mathematica programs are applied. Results. Using 3D modeling, the influence of the stirrer speed on the picture of the distribution of the velocity vectors of the substrate flows in the biogas reactor was studied. Graphs of power consumption at the beginning of mixing for different stirrer speeds were obtained and analyzed, and the levels of energy consumed for mixing biomass during the start-up period and the whole mixing period were compared. A method for determining the energy efficient rotation speed of the stirring mechanism of the electromechanical system of biogas reactors is proposed. Practical value. The results can be used in the construction and modernization of biogas plants to reduce energy consumption of the substrate mixing process. Conclusion. Based on the research, it was concluded that for a paddle two-tier mixer with blades set at an angle of 450 energy-efficient speed, is 40 rpm. At this speed, careful and intensive mixing of the biomass is observed throughout the volume of the tank. The average velocity of flow vectors in the biomass volume is 0,273 m/s. The energy consumed per cycle of biomass mixing is 2471,3 J, and the percentage of energy consumed during the start-up period from the energy consumed during the entire mixing period is 0,62 %. References 19, figures 5.