Annotation of the results obtained in 2022
In the course of the work under the grant, all planned works were completed, namely: 1. A physical model of a dark fermentation plant was created and tested with technical means for intensifying the process (preliminary grinding of the initial waste in a vortex layer apparatus with the simultaneous introduction of iron particles in the pretreatment process) and an automatic control system with digitalization elements that allows recording the main indicators of the dark fermentation process (pH, temperature, volume biogas yield, hydrogen content in biogas, methane content in biogas) every 5 minutes, as well as to control the process of dark fermentation by changing the loading ratio and hydraulic retention time due to the created dosing system and changing the process temperature. 2. A number of experimental studies were carried out, including (1) a study of the process of complex electrophysical action on the initial model substrate in vortex layer apparatus (VLA) under various modes of its operation with an analysis of the chemical composition of the initial and pre-treated substrate and changes in the concentration of ferromagnetic particles in the substrate; (2) experimental determination of the biochemical potential of the OF MSW model pretreated in VLA in a single-phase and two-phase system in a batch mode and the initial substrate in a semi-continuous mode; (3) experimental studies of the dark fermentation of the OF MSW model pre-treated in VLA in a semi-continuous mode on the developed physical model; (4) preliminary experimental studies of the original strategy of sequential production of hydrogen and methane in one reactor due to the separation of stages in time. 3. A number of theoretical studies have been carried out, including (1) calculation of the required heat and power supply of a biogas plant using photovoltaic, thermo-photovoltaic and thermal solar modules of own design in order to compensate for energy costs for the own energy supply of a biogas plant; (2) determination of the composition and design of the solar plant, consisting of solar modules of various designs of our own design, designed to provide the necessary heat and electricity to the biogas plant for various climatic conditions. During the analysis and mathematical processing of data obtained in the course of theoretical and experimental studies, including data obtained on the developed physical model, the following results were obtained: 1. An adequate mathematical model was obtained for the dependence of the concentration of ferromagnetic particles on the operating modes of the VLA (the duration of pretreatment and the mass of working bodies in the VLA chamber) and the concentration of volatile solids in the initial substrate with a determination coefficient of 0.9994. 2. An adequate mathematical model was obtained for the dependence of the maximum production rate of hydrogen (HPR) and methane (MPR) on the operating modes of the VLA (the duration of pretreatment and the mass of working bodies in the VLA chamber) and the concentration of volatile solids in the initial substrate. These models have determination coefficients of 0.8374 (HPR) and 0.8916 (MPR). 3. An adequate mathematical model was obtained for the dependence of the specific energy production rate (EPR) on the VLA operating modes (the duration of pretreatment and the mass of working bodies in the VLA chamber) and the concentration of volatile solids in the initial substrate with a determination coefficient of 0.9860 4. Adequate mathematical models were obtained based on the Gompertz and first order equations, with coefficients of determination in the range of 0.97–1.00, and kinetic constants were determined for the studied processes of dark fermentation of the initial substrate in a periodic and semi-continuous mode. 5. According to a preliminary experiment, the use of pre-treatment of the initial substrate made it possible to increase the hydrogen production rate by 16% compared to the control reactor while increasing the hydrogen content in the biogas to 52.2% in the process of dark fermentation in a semi-continuous mode. 6. The introduction of soluble ferrous sulfate with granular activated carbon allows the activation of hydrogenase activity and the flow of direct interspecies electron transfer (DIET) with the sequential production of hydrogen and methane in one reactor while maintaining a low pH to reduce the activity of methanogens. 7. According to the analysis, solar modules of photovoltaic, thermal and thermal photovoltaic types can provide savings in centralized energy even in the Moscow region when using solar energy to power biogas plants. At the same time, the use of "green" hydrogen obtained with their help can enrich the resulting biogas. 8. New designs of solar modules of our own design are proposed. 9. Technological schemes of biogas plants with two reactors, microbial electrolysis cells have been developed and the principles of their operation with parallel power supply from solar modules of various types have been described. 10. Calculation on the developed Russian software of the necessary heat and power supply of laboratory and industrial biogas plants in various climatic conditions was carried out. 11. Two configurations of solar installations have been developed - on the surfaces of the reactor of a biogas plant and a ground-based arrangement of solar modules with an optimal angle of inclination to the horizon. The project participants prepared and submitted 10 articles to the editors of peer-reviewed journals, of which 4 were published in journals included in the first quartile (Q1) according to SJR, one was accepted for publication (a journal included in the list of HAC). The results of the research carried out under the Project were presented at 7 All-Russian and international conferences.

 

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Annotation of the results obtained in 2023
During the implementation of the grant, all work planned for the second year was completed, which resulted in: 1. A physical model of an anaerobic digestion technological line has been developed and created, consisting of blocks successively located relate to the substrate flow: (1) dosing of the initial substrate, (2) pre-treatment in a vortex layer apparatus, (3) dark fermentation and (4) methanogenesis with integrated microbial electrolysis cell into the reactor. These blocks were combined by an intelligent process control system with the possibility of remote control. 2. A number of experimental studies were carried out, including a study of the influence of the loading frequency on the efficiency and stability of the processes of (1) dark fermentation with sequential methanogenesis in a separate reactor with an integrated microbial electrolysis cell (2) without applying a potential difference to the electrodes and (3) with the supply of 1.2 V to electrodes. 3. A number of theoretical studies were carried out, including (1) the development of an experimental plan for 2023 and 2024 based on a central composite design using response surface methodology to determine the optimal operating conditions of the anaerobic digestion process line in the potential difference range of 0-2.4 V at a frequency of supply of fresh substrate 8-24 hours; (2) determination of the conversion coefficients of energy supplied to the dark fermentation reactor. 4. An analysis was carried out of (1) the profile of planktonic and attached microbial communities based on sequencing of the 16S rRNA gene sequence; (2) electroactivity of biofilms using the cyclic voltammetry (CV) method formed in different parts of the microbial electrolysis cell and in the inert space; (3) the chemical composition of dark fermentation products. In addition, as a result of the work done, developed solar modules of various designs were manufactured for heat and electricity supply to a pilot biogas plant with increased efficiency of biogas production using a microbiological electrolysis cell, designed to compensate for energy costs for the biogas plant’s own energy supply. The design of the developed solar modules for heat and power supply of a biogas plant with increased efficiency of biogas production using a microbiological electrolysis cell was optimized. A design, technological manufacturing instructions have been developed and a photovoltaic module in the form of a siding panel has been manufactured using highly efficient photovoltaic converters with a one-sided contact grid and a two-component polysiloxane compound, which has a number of advantages over ethylene vinyl acetate films. A design, technological instructions have been developed and a solar thermal module in the form of a siding panel of a simple and inexpensive design has been manufactured using domestically produced components, the design of which also provides for the possibility of adding additional front and rear heat-insulating screens, which will reduce the thermal losses of the module and increase its thermal efficiency with a small rising cost of construction. A design, technological manufacturing instructions have been developed and a thermal photovoltaic module in the form of a siding panel has been manufactured using highly efficient photovoltaic converters with a one-sided contact grid and water cooling, as well as a two-component polysiloxane compound. The use of a thermal photovoltaic module allows you to save space and money when using solar modules, cooling photovoltaic converters allows you to increase their electrical efficiency, water cooling has a simple heat removal system, and a two-component polysiloxane compound will provide high optical transparency and a long life of rated electrical power. The designs of the developed solar modules were optimized (if necessary, changes were made to their designs), during which, along with analytical calculations, a finite element analysis software package was used to model and visualize deformations and thermal processes. As a result of the modeling, the high steady-state temperature of the photovoltaic converters of the module was determined, to reduce which and remove thermal energy in the form of heating the coolant, which increases both the electrical efficiency and the overall efficiency of the solar module, the design of a water-cooled thermophotovoltaic module was proposed, as a result of modeling the rigidity of which it was The effect of gravity was assessed when significant movements and deformations of the thermophotovoltaic module were not detected. The main task of optimizing the design of thermal photovoltaic and thermal modules was to determine the optimal geometric parameters of the heat removal channel that removes thermal energy from the thermal photodetector, when various geometric parameters of the cooling channel and various modes of its operation were considered. A water cooling radiator with a rectangular channel in cross-section has been developed in order to ensure direct and immediate contact of the coolant with a thermal metal photodetector, where the width of the channel can be provided in a wide range, and its height is minimal, when heating of the coolant layers will be uniform on all sides due to the high thermal conductivity of the coolant itself. metal channel. An assessment was also made of the influence of the distance between the cooling channels on the uniformity of heating of the thermal photodetector and heat removal by the coolant, where in the optimized version there is a noticeably more uniform distribution of temperatures of the thermal photodetector between the channels. The experimental data obtained show that the developed method for intensifying the dark fermentation process is extremely effective: pre-treatment of the food waste model in a vortex layer apparatus before dark fermentation allows increasing the biohydrogen yield by more than 7 times. The use of a microbial electrolysis cell in a anaerobic digestion system with the electricity supply from a solar photovoltaic panel makes it possible to convert solar energy and store it in the form of methane, while simultaneously accelerating the process of anaerobic bioconversion of organic waste matter. The project participants prepared and sent 10 articles to the editors of peer-reviewed journals, of which 7 were published in journals included in the first quartile (Q1) according to SJR. The results of the research carried out under the Project were presented at 4 All-Russian and international conferences.

 

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