Markina L. Automation of processes of kneading from grain raw materials and its water-heat treatment in alcohol production

The dissertation is devoted to improving the efficiency of ethyl alcohol production from grain mixtures by ensuring the stability of semi-finished product parameters at the initial stage of mash preparation with its water-thermal treatment. The mash preparation process is accompanied by strong disturbances, which complicates the accurate compliance with mash quality indicators. The lack of effective automated control over the quality indicators of the mash in the vast majority of cases leads to a violation of technological modes at subsequent stages, which reduces the quality of ethyl alcohol and causes an excess consumption of energy resources and raw materials. Therefore, the task of automating the processes of preparing mash from grain raw materials and its water-thermal treatment in alcohol production is relevant, which will reduce the consumption of input materials and ensure the stability of subsequent stages of production. The paper analyzes the state of automation in alcohol preparation areas and obtains a relationship between the concentration of dry substances, density, and viscosity, which made it possible to create an effective system for controlling the process of preparing mash and its water-thermal treatment. Based on the results of experimental studies, the dependence of the concentration of dissolved starch in the mash on density, viscosity, and temperature was established, which made it possible to select control coordinates and develop a multi-loop control system for the mash preparation process and its water-thermal treatment. A comparative analysis of functional diagrams for automating the dough preparation process was conducted, and algorithms were developed and implemented that made it possible to combine all stages of dough preparation and its water-thermal treatment into a single automated system. An approach to modeling the dough preparation process and its water-heat treatment was proposed, namely, a generalized mixing model was created as a control object, which made it possible to synthesize control influences and quantitatively evaluate informative parameters: starch concentration and dough volume. The power consumption of the mixer is used as an indirect method of measuring viscosity, which has made it possible to effectively control this indicator, which is critical for the stability of the dough preparation process. The results of the experiments confirmed the feasibility of taking into account temperature and viscosity in the system for controlling the dough preparation and water-heat treatment process. For the first time, an automatic control system was developed for the complex process of dough preparation and its water-heat treatment, which made it possible to increase the efficiency of the technological process and the quality of the semi-finished product. A study of the control system using a PID-controller and an LQR-controller was conducted, which made it possible to select a control law that ensures control accuracy and improves control quality in dynamic modes. An LQR controller was synthesized for the automated control system of the dough preparation process and its water-thermal treatment, and its parameters were optimized, which improved the quality indicators of the control system and increased the speed of regulation of the volume and concentration of dissolved starch in the dough. The solutions obtained were applied in production conditions (in particular at the Lutsk, Marylivka, and Boroksky distilleries), which confirmed a reduction in grain, enzyme, and energy costs, as well as an increase in the overall efficiency of the process by up to 5% due to the stabilization of mash parameters and optimization of water and heat treatment. Keywords: mash, water-heat treatment, concentration of dissolved starch, automatic control system, regulator, mathematical model, algorithm.