Pub Date : 2022-04-30DOI: 10.17588/2072-2672.2022.2.021-028
A. Sokolsky, E. Gusev, P. Shomov, V. Pronin
The generation of electrical energy at thermal and nuclear power plants is associated with outward heat transmission of large amount. Cooling devices (cooling towers, spray pools, reservoirs) are used for its utilization. The increase of the efficiency of the cooling capacity of this equipment in the circulating water supply system of the CHP plant is occurred due to a decrease of temperatures that meet the optimal technical and economic performance of the facility. The studies of I.I. Makarova, V.A. Gladkova, B.S. Farfarovsky, Z.K. Maimekova, S.A. Suprun are devoted to these issues. The aim of the study is to develop a methodology to calculate the process of cooling technical water to create an operating temperature mode of the equipment during condensation of the waste heat of steam turbines and to minimize the amount of additional water from the Tom River in the warm season. To evaluate the operation of spray devices the authors have used experimental data obtained during the survey of the cooling pond of the West Siberian CHP plant in Novokuznetsk city and methods of physical modeling of heat and mass transfer. To increase the efficiency of technical water cooling at the CHP plant, it is proposed to install spray devices in addition to the existing cooling pond. A method has been developed to calculate the process of water cooling in spray devices during collaboration with a cooling pond. The method is based on the calculation of the optimal water temperature at the intake point in accordance with the operating parameters of turbine generator condensers. The method differs from the existing ones as it considers the influence of heat transfer and mass transfer phenomena in the boundary layer near the surface of dispersed drops water. The experimental and calculated results confirm that the use of spray devices in the cooling pond reduces the amount of additional water taken from the Tom River compared to its limit flow by almost 10 times at the established temperature difference during the condensation of exhaust steam in the summer period of the year. The method to calculate the cooling of technical water in a cooling pond with spray devices is recommended for implementation at the West Siberian CHP plant in Novokuznetsk city.
{"title":"Method of heat and mass transfer calculation of cooling technical water process at CHP plant when cooling pond with spray devices is operated","authors":"A. Sokolsky, E. Gusev, P. Shomov, V. Pronin","doi":"10.17588/2072-2672.2022.2.021-028","DOIUrl":"https://doi.org/10.17588/2072-2672.2022.2.021-028","url":null,"abstract":"The generation of electrical energy at thermal and nuclear power plants is associated with outward heat transmission of large amount. Cooling devices (cooling towers, spray pools, reservoirs) are used for its utilization. The increase of the efficiency of the cooling capacity of this equipment in the circulating water supply system of the CHP plant is occurred due to a decrease of temperatures that meet the optimal technical and economic performance of the facility. The studies of I.I. Makarova, V.A. Gladkova, B.S. Farfarovsky, Z.K. Maimekova, S.A. Suprun are devoted to these issues. The aim of the study is to develop a methodology to calculate the process of cooling technical water to create an operating temperature mode of the equipment during condensation of the waste heat of steam turbines and to minimize the amount of additional water from the Tom River in the warm season. To evaluate the operation of spray devices the authors have used experimental data obtained during the survey of the cooling pond of the West Siberian CHP plant in Novokuznetsk city and methods of physical modeling of heat and mass transfer. To increase the efficiency of technical water cooling at the CHP plant, it is proposed to install spray devices in addition to the existing cooling pond. A method has been developed to calculate the process of water cooling in spray devices during collaboration with a cooling pond. The method is based on the calculation of the optimal water temperature at the intake point in accordance with the operating parameters of turbine generator condensers. The method differs from the existing ones as it considers the influence of heat transfer and mass transfer phenomena in the boundary layer near the surface of dispersed drops water. The experimental and calculated results confirm that the use of spray devices in the cooling pond reduces the amount of additional water taken from the Tom River compared to its limit flow by almost 10 times at the established temperature difference during the condensation of exhaust steam in the summer period of the year. The method to calculate the cooling of technical water in a cooling pond with spray devices is recommended for implementation at the West Siberian CHP plant in Novokuznetsk city.","PeriodicalId":23635,"journal":{"name":"Vestnik IGEU","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84578168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-30DOI: 10.17588/2072-2672.2022.2.015-020
E. Karpychev
An urgent task of the research is to describe the properties of the sludge formed during coagulation depending on the type of water supply source. Namely, the aim is to study the sorption capacity of the sludge for the main components removed from the water (iron compounds, organic substances, and silicic acid compounds). This indicator allows you to directly determine the effectiveness of the coagulation. When comparing the actual values of this indicator with practically obtainable values, one can say about the lack or excess of the coagulant supplied for processing. To calculate the specific sorption capacities of the sludge, the following indicators have been used: organic content, the weight concentration of silicic acid compounds in terms of SiO2 and the weight concentration of iron compounds in terms of Fe. After drying and calcining the sludge, the resulting mineral residue has been dissolved in the solution, and the content of the final components was determined. Conventional water analysis methods have been applied. For the first time, a method is proposed to determine the specific sorption capacities of aluminum hydroxide sludge for organic compounds, for iron compounds in terms of Fe, for silicic acid compounds in terms of SiO2. A classification of natural low-turbidity waters with an increased content of iron-organic compounds is proposed. Within the framework of the proposed classification of waters, the authors have obtained previously undetermined actual specific sorption capacities of the sludge. Recommendations have been given to get practical importance values of the sorption characteristics of the sludge. The proposed method to calculate the sorption capacity of aluminum hydroxide sludge and index of sorption capacity of the sludge are recommended to be used as a parameter that determines the conditions and efficiency of application of the aluminum sulfate coagulation technology. Excessive doses of the coagulant that provide a sorption capacity of the sludge greater than the recommended values, lead to an excessive consumption of both the reagent itself and purge water. Thus, some measures can be taken to bring the sorption capacity of the sludge to practically achievable values, for example, aquatic acidification.
{"title":"Determination of sorption characteristics of aluminum hydroxide sludge formed at the stage of pre-purification of water treatment plant","authors":"E. Karpychev","doi":"10.17588/2072-2672.2022.2.015-020","DOIUrl":"https://doi.org/10.17588/2072-2672.2022.2.015-020","url":null,"abstract":"An urgent task of the research is to describe the properties of the sludge formed during coagulation depending on the type of water supply source. Namely, the aim is to study the sorption capacity of the sludge for the main components removed from the water (iron compounds, organic substances, and silicic acid compounds). This indicator allows you to directly determine the effectiveness of the coagulation. When comparing the actual values of this indicator with practically obtainable values, one can say about the lack or excess of the coagulant supplied for processing. To calculate the specific sorption capacities of the sludge, the following indicators have been used: organic content, the weight concentration of silicic acid compounds in terms of SiO2 and the weight concentration of iron compounds in terms of Fe. After drying and calcining the sludge, the resulting mineral residue has been dissolved in the solution, and the content of the final components was determined. Conventional water analysis methods have been applied. For the first time, a method is proposed to determine the specific sorption capacities of aluminum hydroxide sludge for organic compounds, for iron compounds in terms of Fe, for silicic acid compounds in terms of SiO2. A classification of natural low-turbidity waters with an increased content of iron-organic compounds is proposed. Within the framework of the proposed classification of waters, the authors have obtained previously undetermined actual specific sorption capacities of the sludge. Recommendations have been given to get practical importance values of the sorption characteristics of the sludge. The proposed method to calculate the sorption capacity of aluminum hydroxide sludge and index of sorption capacity of the sludge are recommended to be used as a parameter that determines the conditions and efficiency of application of the aluminum sulfate coagulation technology. Excessive doses of the coagulant that provide a sorption capacity of the sludge greater than the recommended values, lead to an excessive consumption of both the reagent itself and purge water. Thus, some measures can be taken to bring the sorption capacity of the sludge to practically achievable values, for example, aquatic acidification.","PeriodicalId":23635,"journal":{"name":"Vestnik IGEU","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81422251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-28DOI: 10.17588/2072-2672.2022.1.038-045
V. Golov, D. Kormilitsyn, O. Sukhanova
According to the rules of installation of electricity-generating equipment, synchronous machines (generators, compensators, electric motors) must be equipped with automatic excitation control devices. Their application has a positive effect on the stability indicators and electrical power-engineering system modes. Currently, the development of industry and an increase in the number of consumers require transmission capacity growth of existing 220 kV power transmission lines. The use of controlled series compensation devices can significantly increase the transmission capacity of a power transmission line, however, there is a problem of stable operation of the electric power-engineering system. To choose the methods for control parameters of automatic excitation control and controlled series compensation device, it is advisable to analyze the oscillatory steady-state stability of the electric power-engineering system that contain a controlled 220 kV power transmission line when regulating the excitation of its generators. Methods of mathematical modeling of the electric power system, the theory of long-distance power lines and electromechanical transients, methods of analyzing the stability of electric power systems are used. The original software in the C++ programming language has been used as a modeling tool. The authors have analyzed the influence of controlled series compensation of high voltage transmission line and generators of automatic excitation control on oscillatory steady-state stability of electric power system. The parameters value of regulation of the controlled series compensation device and the automatic excitation control are determined, considering restrictions while maintaining the positive influence of these devices. Zones of stability of the examined electric power-engineering system are formed depending on setup variable of the devices under consideration. The obtained results can be used to enhance oscillatory steady-state stability of electric power system with controlled series compensation device and automatic excitation control systems.
{"title":"Analysis of influence of controlled high voltage line and automatic excitation control generators on oscillatory steady-state stability of electric-power system","authors":"V. Golov, D. Kormilitsyn, O. Sukhanova","doi":"10.17588/2072-2672.2022.1.038-045","DOIUrl":"https://doi.org/10.17588/2072-2672.2022.1.038-045","url":null,"abstract":"According to the rules of installation of electricity-generating equipment, synchronous machines (generators, compensators, electric motors) must be equipped with automatic excitation control devices. Their application has a positive effect on the stability indicators and electrical power-engineering system modes. Currently, the development of industry and an increase in the number of consumers require transmission capacity growth of existing 220 kV power transmission lines. The use of controlled series compensation devices can significantly increase the transmission capacity of a power transmission line, however, there is a problem of stable operation of the electric power-engineering system. To choose the methods for control parameters of automatic excitation control and controlled series compensation device, it is advisable to analyze the oscillatory steady-state stability of the electric power-engineering system that contain a controlled 220 kV power transmission line when regulating the excitation of its generators. Methods of mathematical modeling of the electric power system, the theory of long-distance power lines and electromechanical transients, methods of analyzing the stability of electric power systems are used. The original software in the C++ programming language has been used as a modeling tool. The authors have analyzed the influence of controlled series compensation of high voltage transmission line and generators of automatic excitation control on oscillatory steady-state stability of electric power system. The parameters value of regulation of the controlled series compensation device and the automatic excitation control are determined, considering restrictions while maintaining the positive influence of these devices. Zones of stability of the examined electric power-engineering system are formed depending on setup variable of the devices under consideration. The obtained results can be used to enhance oscillatory steady-state stability of electric power system with controlled series compensation device and automatic excitation control systems.","PeriodicalId":23635,"journal":{"name":"Vestnik IGEU","volume":"292 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77751698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-28DOI: 10.17588/2072-2672.2022.1.005-011
V. Gorbynov, G. A. Perevezentsev, S.S. Teplyakova, M. Mechtaeva
Thermal insulation, porous composite, ceramic, charge materials are frequently used in the energy industry. The materials are heat treated to improve the structure and give them the desired properties required for specific production conditions. The important task is to assess the influence of geometric parameters of the fractal-like structure and radiation heat transfer on the thermophysical properties of porous bodies. For numerical description of porous bodies, the technique of replacing geometry of porous body with the bodies with a fractal-like structure having self-similarity properties is significant. The object under study is an array of blanks arranged chaotically, the structures that are called bulk cages. The porous body is replaced by a fractal cube structure of the 2nd rank of partitioning. The simulation has been performed in the COMSOL Multiphysics software based on a three-dimensional model of the Sierpinski carpet. Since the distribution of heat can be non-uniformed over the structure of the object, three variants of the fractal-like cubic structure cross section are considered. A method to determine the effective thermal conductivity coefficients based on the use of fractal-like structures has been developed. Depending on the cross sections, one-dimensional computational models with sufficient accuracy for engineering analysis are obtained. The effective thermal conductivity coefficients are determined. The results of data analysis have shown that the geometric parameters of the structure and radiation heat transfer significantly affect the effective coefficient of thermal conductivity at high temperatures. In comparison to the currently available approaches, the developed method allows solving the problem of determining thermophysical properties without physical experiments. The technique used in the study may be used for mathematical modeling of heat exchange processes of heat-power facilities when calculating temperature fields and determining heating modes.
{"title":"Methodology to determine coefficients of effective thermal conductivity when heating porous bodies using fractal-like structures","authors":"V. Gorbynov, G. A. Perevezentsev, S.S. Teplyakova, M. Mechtaeva","doi":"10.17588/2072-2672.2022.1.005-011","DOIUrl":"https://doi.org/10.17588/2072-2672.2022.1.005-011","url":null,"abstract":"Thermal insulation, porous composite, ceramic, charge materials are frequently used in the energy industry. The materials are heat treated to improve the structure and give them the desired properties required for specific production conditions. The important task is to assess the influence of geometric parameters of the fractal-like structure and radiation heat transfer on the thermophysical properties of porous bodies. For numerical description of porous bodies, the technique of replacing geometry of porous body with the bodies with a fractal-like structure having self-similarity properties is significant. The object under study is an array of blanks arranged chaotically, the structures that are called bulk cages. The porous body is replaced by a fractal cube structure of the 2nd rank of partitioning. The simulation has been performed in the COMSOL Multiphysics software based on a three-dimensional model of the Sierpinski carpet. Since the distribution of heat can be non-uniformed over the structure of the object, three variants of the fractal-like cubic structure cross section are considered. A method to determine the effective thermal conductivity coefficients based on the use of fractal-like structures has been developed. Depending on the cross sections, one-dimensional computational models with sufficient accuracy for engineering analysis are obtained. The effective thermal conductivity coefficients are determined. The results of data analysis have shown that the geometric parameters of the structure and radiation heat transfer significantly affect the effective coefficient of thermal conductivity at high temperatures. In comparison to the currently available approaches, the developed method allows solving the problem of determining thermophysical properties without physical experiments. The technique used in the study may be used for mathematical modeling of heat exchange processes of heat-power facilities when calculating temperature fields and determining heating modes.","PeriodicalId":23635,"journal":{"name":"Vestnik IGEU","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80051953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-28DOI: 10.17588/2072-2672.2022.1.054-063
S. Nesterov, I. Egorov
The small size of the working gap in the sealer makes many physical measurements difficult or impossible. The main way to study the processes inside the device is to use analytical and numerical mathematical modeling. Most researchers apply finite-element calculation of magnetic field and analytically find the difference in pressure. Currently, there are few studies devoted to multiphysics numerical calculations of the processes in magnetorheological seal. The use of numerical models allows considering the dependence of rheological properties of magnetic fluid on hydrodynamic, temperature and magnetic fields, the real geometry of the working zone. Compared to the analytical models, a numerical one includes a smaller number of assumptions and allows visualizing various flow parameters, which are especially important for the analysis. The purpose of this study is to analyze the effect of the deformation of the magnetorheological plug in case of pressure difference held by the sealer. The study is based on the developed numerical model with the related calculation of magnetic and hydrodynamic fields. The study is carried out based on the theories of ferrohydrodynamics, hydrodynamics and electromagnetic field. Integrated finite-element modeling of the magnetic and hydrodynamic fields of the magnetorheological sealer in Comsol Мultiphysics has been used. A numerical model of the magnetorheological sealer characterized by automatic rearrangement of the boundaries of the liquid plug based on the balance of pressures inside the liquid has been developed. The distribution results of magnetic induction and pressure in the working gap of the sealer, considering changes in the boundaries of the magnetic fluid, has been obtained. Comparison of the results of the obtained retained pressure drop and the results of other models has been carried out. A numerical mathematical model that considers the deformation of the magnetorheological plug has been developed. The model makes it possible to estimate the influence of centrifugal forces of the rotating shaft on the retained pressure drop. The results can be used to create high-speed seal components. The difference of the value of analytical calculation does not exceed 5 %. The assumption about full filling of the working gap with magnetic fluid 2,5 times underestimates the retained pressure difference at high shaft rotation speeds.
{"title":"Analysis of processes in magnetorheological sealer considering for magnetic fluid deformation","authors":"S. Nesterov, I. Egorov","doi":"10.17588/2072-2672.2022.1.054-063","DOIUrl":"https://doi.org/10.17588/2072-2672.2022.1.054-063","url":null,"abstract":"The small size of the working gap in the sealer makes many physical measurements difficult or impossible. The main way to study the processes inside the device is to use analytical and numerical mathematical modeling. Most researchers apply finite-element calculation of magnetic field and analytically find the difference in pressure. Currently, there are few studies devoted to multiphysics numerical calculations of the processes in magnetorheological seal. The use of numerical models allows considering the dependence of rheological properties of magnetic fluid on hydrodynamic, temperature and magnetic fields, the real geometry of the working zone. Compared to the analytical models, a numerical one includes a smaller number of assumptions and allows visualizing various flow parameters, which are especially important for the analysis. The purpose of this study is to analyze the effect of the deformation of the magnetorheological plug in case of pressure difference held by the sealer. The study is based on the developed numerical model with the related calculation of magnetic and hydrodynamic fields. The study is carried out based on the theories of ferrohydrodynamics, hydrodynamics and electromagnetic field. Integrated finite-element modeling of the magnetic and hydrodynamic fields of the magnetorheological sealer in Comsol Мultiphysics has been used. A numerical model of the magnetorheological sealer characterized by automatic rearrangement of the boundaries of the liquid plug based on the balance of pressures inside the liquid has been developed. The distribution results of magnetic induction and pressure in the working gap of the sealer, considering changes in the boundaries of the magnetic fluid, has been obtained. Comparison of the results of the obtained retained pressure drop and the results of other models has been carried out. A numerical mathematical model that considers the deformation of the magnetorheological plug has been developed. The model makes it possible to estimate the influence of centrifugal forces of the rotating shaft on the retained pressure drop. The results can be used to create high-speed seal components. The difference of the value of analytical calculation does not exceed 5 %. The assumption about full filling of the working gap with magnetic fluid 2,5 times underestimates the retained pressure difference at high shaft rotation speeds.","PeriodicalId":23635,"journal":{"name":"Vestnik IGEU","volume":"69 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78693612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-28DOI: 10.17588/2072-2672.2022.1.022-037
E. Tyurina, A. S. Mednikov, P. Elsukov, P. Zharkov, E. Zubova
The study is relevant due to increased interest to the underground coal gasification technologies (UCG). The interest is determined by the depletion of world oil and gas reserves, the significant amount of coal deposits in various countries of the world, the growing energy demand, as well as the threat of global climate change. The possibility to use technologies of underground gasification of low-grade coal with complex geological environment is huge. Recently, interest to UCG has grown dramatically. In contrast to all major programs of the 20th century, this unprecedented interest is mainly stimulated by private capital in response to high oil and energy prices. Thus, the studies of UCG are carried out. And more than 30 tests are planned in Australia, China, India, South Africa, New Zealand, Canada, and the United States. The development of competitive gas-based technologies of production of electricity and synthetic liquid fuels is a high-priority task. The studies have been carried out using a mathematical model of the unit for the production of electricity and methanol. To design a mathematical model, a software, or the system of machine programs development (SMPP) has been used. It has been developed at Melentiev Energy Systems Institute of Siberian Branch of the Russian Academy of Sciences (ESI SB RAS). The article presents the results of the study of the use of UCG for the coproduction of synthetic liquid fuel (methanol) and electricity. A detailed mathematical model of electricity and methanol production unit has been developed. Based on the model, technical and economic optimization of the schemes and parameters has been carried out. It made possible to estimate the competitiveness conditions of the proposed method of coal processing. In addition, the sensitivity of the economic indicators of the unit to changes in external conditions has been studied. Based on the results of the analysis of the cost of diesel fuel in the eastern regions of Russia, the authors have made the conclusion that at present methanol produced by the energy technological unit is as competitive as delivered expensive diesel fuel. The introduction of such systems is economically reasonable in the near future.
{"title":"Use of underground coal gasification gas for co-production of electric power and synthetic liquid fuel","authors":"E. Tyurina, A. S. Mednikov, P. Elsukov, P. Zharkov, E. Zubova","doi":"10.17588/2072-2672.2022.1.022-037","DOIUrl":"https://doi.org/10.17588/2072-2672.2022.1.022-037","url":null,"abstract":"The study is relevant due to increased interest to the underground coal gasification technologies (UCG). The interest is determined by the depletion of world oil and gas reserves, the significant amount of coal deposits in various countries of the world, the growing energy demand, as well as the threat of global climate change. The possibility to use technologies of underground gasification of low-grade coal with complex geological environment is huge. Recently, interest to UCG has grown dramatically. In contrast to all major programs of the 20th century, this unprecedented interest is mainly stimulated by private capital in response to high oil and energy prices. Thus, the studies of UCG are carried out. And more than 30 tests are planned in Australia, China, India, South Africa, New Zealand, Canada, and the United States. The development of competitive gas-based technologies of production of electricity and synthetic liquid fuels is a high-priority task. The studies have been carried out using a mathematical model of the unit for the production of electricity and methanol. To design a mathematical model, a software, or the system of machine programs development (SMPP) has been used. It has been developed at Melentiev Energy Systems Institute of Siberian Branch of the Russian Academy of Sciences (ESI SB RAS). The article presents the results of the study of the use of UCG for the coproduction of synthetic liquid fuel (methanol) and electricity. A detailed mathematical model of electricity and methanol production unit has been developed. Based on the model, technical and economic optimization of the schemes and parameters has been carried out. It made possible to estimate the competitiveness conditions of the proposed method of coal processing. In addition, the sensitivity of the economic indicators of the unit to changes in external conditions has been studied. Based on the results of the analysis of the cost of diesel fuel in the eastern regions of Russia, the authors have made the conclusion that at present methanol produced by the energy technological unit is as competitive as delivered expensive diesel fuel. The introduction of such systems is economically reasonable in the near future.","PeriodicalId":23635,"journal":{"name":"Vestnik IGEU","volume":"78 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81324716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-28DOI: 10.17588/2072-2672.2022.1.046-053
S. Derkachev
Nonsymmetrical modes in the external power supply network during operation can be caused by several reasons: phase failure due to strong wind or glaciation of overhead power lines, wire burnout due to persistent short circuits, open phase automatic reclosing. In case of open phase condition, the external power supply network, synchronous and asynchronous electric motors are powered along the two phases that are in operation. It leads to the negative sequence current, which poses maximum danger for electric motors, since it causes additional heating and, as a result, premature damage. Therefore, the currently important goal of the project is to study transient processes of the motor load when an open phase mode occurs in the external power supply network and to design microprocessor protection of electrical motors against phase failure in the supply network. To achieve the goal, a computer simulation method is used, based on mathematical models of the elements of electrical network presented as the systems of differential equations in a three-phase coordinate system. The regularities of the flow of transient processes in synchronous and asynchronous electric motors in case of open phase modes in both the internal and external power supply networks have been established. Thus, it is possible to develop an algorithm of the operation of microprocessor protection of electrical motors against phase failure in the external power supply network. The proposed algorithm is based on monitoring the negative sequence current level and the absence of current in one of the phases at the section input. The obtained results show that the proposed algorithm to protect electrical motors against open phase modes in an external power supply network has a high selectivity. Its use as a starting element of the fast-acting automatic transfer switch device allows you to provide uninterrupted power supply for enterprises with a continuous technological process.
{"title":"Microprocessor protection of electrical motors against phase failure in external power supply network","authors":"S. Derkachev","doi":"10.17588/2072-2672.2022.1.046-053","DOIUrl":"https://doi.org/10.17588/2072-2672.2022.1.046-053","url":null,"abstract":"Nonsymmetrical modes in the external power supply network during operation can be caused by several reasons: phase failure due to strong wind or glaciation of overhead power lines, wire burnout due to persistent short circuits, open phase automatic reclosing. In case of open phase condition, the external power supply network, synchronous and asynchronous electric motors are powered along the two phases that are in operation. It leads to the negative sequence current, which poses maximum danger for electric motors, since it causes additional heating and, as a result, premature damage. Therefore, the currently important goal of the project is to study transient processes of the motor load when an open phase mode occurs in the external power supply network and to design microprocessor protection of electrical motors against phase failure in the supply network. To achieve the goal, a computer simulation method is used, based on mathematical models of the elements of electrical network presented as the systems of differential equations in a three-phase coordinate system. The regularities of the flow of transient processes in synchronous and asynchronous electric motors in case of open phase modes in both the internal and external power supply networks have been established. Thus, it is possible to develop an algorithm of the operation of microprocessor protection of electrical motors against phase failure in the external power supply network. The proposed algorithm is based on monitoring the negative sequence current level and the absence of current in one of the phases at the section input. The obtained results show that the proposed algorithm to protect electrical motors against open phase modes in an external power supply network has a high selectivity. Its use as a starting element of the fast-acting automatic transfer switch device allows you to provide uninterrupted power supply for enterprises with a continuous technological process.","PeriodicalId":23635,"journal":{"name":"Vestnik IGEU","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85720985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-28DOI: 10.17588/2072-2672.2022.1.012-021
S. Bannikova
High values of standard heat losses in the heating networks of central heat supply systems indicate an opportunity to increase their energy efficiency. Сurrently available mathematical models of heat networks are described in the scientific studies of Polovnikov V.Yu., Kuznetsov G.V., Tarasevich E.I. But they do not solve the problem of assessing changes of the thermal networks state when energy-saving measures are used. The purpose of the study is to determine the permissible heat perception of the device collector for utilization of heat losses in the heating main channel. The study is based on the development and research of mathematical models of heat exchange processes in the heat supply network. A mathematical modeling method is chosen to search for acceptable operating modes of this device. The method can help to determine properly changes in the operation of the heat network. A descriptive mathematical model with distributed parameters based on differential equations with partial derivatives is used in modeling heat transfer processes in the heat network. The model is implemented using the finite element method. The authors propose a device for the utilization of heat losses in the heating channel. The authors have developed mathematical models of heat transfer processes in heat networks of underground trench laying in nonaccessible channels in a traditional design with the use of a heat-reflecting screen and combined action of the network and the device for the utilization of heat losses in the heat channel. Based on the comparison of the calculation results, the permissible heat perception value of the device collector for the utilization of heat losses has been determined. It equals to 90 % of the initial thermal losses. Mathematical models have been verified by comparing the results obtained and the experimental data with an error of less than 6 %. The developed mathematical models allow us to study the influence of heat perception of the device collector and the heat-reflecting screen on the operating mode of the heat network. It can be used to determine the geometric parameters of the collector of the device.
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Pub Date : 2022-02-28DOI: 10.17588/2072-2672.2022.1.064-072
D. S. Protsko, S. Panov, A. Khvostov, E. Shipilova
The energy development vector is currently aimed at increasing application of renewable fuels. Air pollution is one of the most significant consequences of fuel combustion. The issue is of current importance for small power plants subordinate to the Department of Public Utilities of the Ministry of Defense of the Russian Federation. To solve the problem, it is necessary to both update the existing equipment and to develop fundamentally new gas cleaning equipment that have high cleaning efficiency, reduced hydraulic resistance and smaller size. Thus, these issues determine the relevance of development of mathematical models of filtering equipment operation. To solve the problem, the method of mathematical modeling is used. The model uses the mathematical apparatus of aerohydromechanics using the k- turbulence model. The study of the influence of parameters on the flow of the process has been carried out by numerical methods in the computational fluid dynamics software environment. A mathematical model is proposed that allows us to determine and design pressure and velocity fields in the gap between the filter housing and the filter element at different speeds of the inlet gas flow. It makes possible to quickly assess the degree of clogging of the filter according to the dynamics of pressure changes at the outlet pipe of the filter. The results of the numerical experiment have been confirmed by laboratory studies. The developed mathematical model of the process of tangential regeneration of filter baffles makes it possible to estimate the pressure and velocity fields in the gap that influence on the entrainment of dust particles. Thereby one can predict the efficiency of the filter depending on the specific gas load and the width of the gap. The results of numerical experiments are consistent with the physical concepts of the process. They prove the prospects of the method to create a tangential flow to remove the settled particles of the dispersed phase from the surface of the filter element. The developed model can be used in the engineering practice of designing filters and controlling the filtration process.
{"title":"Development of mathematical model of tangential regeneration of filter partitions of small-sized dust collecting devices of power plants","authors":"D. S. Protsko, S. Panov, A. Khvostov, E. Shipilova","doi":"10.17588/2072-2672.2022.1.064-072","DOIUrl":"https://doi.org/10.17588/2072-2672.2022.1.064-072","url":null,"abstract":"The energy development vector is currently aimed at increasing application of renewable fuels. Air pollution is one of the most significant consequences of fuel combustion. The issue is of current importance for small power plants subordinate to the Department of Public Utilities of the Ministry of Defense of the Russian Federation. To solve the problem, it is necessary to both update the existing equipment and to develop fundamentally new gas cleaning equipment that have high cleaning efficiency, reduced hydraulic resistance and smaller size. Thus, these issues determine the relevance of development of mathematical models of filtering equipment operation. To solve the problem, the method of mathematical modeling is used. The model uses the mathematical apparatus of aerohydromechanics using the k- turbulence model. The study of the influence of parameters on the flow of the process has been carried out by numerical methods in the computational fluid dynamics software environment. A mathematical model is proposed that allows us to determine and design pressure and velocity fields in the gap between the filter housing and the filter element at different speeds of the inlet gas flow. It makes possible to quickly assess the degree of clogging of the filter according to the dynamics of pressure changes at the outlet pipe of the filter. The results of the numerical experiment have been confirmed by laboratory studies. The developed mathematical model of the process of tangential regeneration of filter baffles makes it possible to estimate the pressure and velocity fields in the gap that influence on the entrainment of dust particles. Thereby one can predict the efficiency of the filter depending on the specific gas load and the width of the gap. The results of numerical experiments are consistent with the physical concepts of the process. They prove the prospects of the method to create a tangential flow to remove the settled particles of the dispersed phase from the surface of the filter element. The developed model can be used in the engineering practice of designing filters and controlling the filtration process.","PeriodicalId":23635,"journal":{"name":"Vestnik IGEU","volume":"76 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86042528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-28DOI: 10.17588/2072-2672.2021.6.005-018
A. Larin, E. Karpychev, N.N. Yarunina, A.Y. Loginova
Under the conditions of modernization of Russian thermal power plants (TPP), water treatment plants based on imported membrane technologies are often put into operation without consideration of the quality of the source (natural) water and variable-performance operating modes. At the same time long-running water treatment plants and their capabilities are not considered. In this regard, the cost of additional water is three or more times higher, and the average output is respectively lower than at traditional water treatment plants. Often, one doesn’t take the advantages of reverse osmosis installations based on the rejection of the use of aggressive reagents such as sulfuric acid, etc. The aim of the study is to increase the efficiency of desalinated water production. It is especially important to conduct studies of natural waters with high content of iron-organic compounds characteristic of the regions of the center and north of Russia. The authors have carried out laboratory studies of various, primarily new filter materials, regents, and devices, both at the stages of pre-purification of water i.e., clarification, and at the stages of demineralization of clarified water. Water treatment plants of Ivanovo combined-cycle plant (CCP) and Cherepovets state district power station (GRES) are considered as the subject of the research. It is found out that if one applies ion-exchange and membrane water treatment technologies to treat water with high content of iron-organic compounds, high-quality desalinated water can be obtained. The properties of water are the following: specific electrical conductivity of no more than 0,2 mcm/cm and permanganate oxidizability of no more than 1 MgO/l. Results of studies at the Ivanovo CCP and Cherepovets GRES have shown practicability to coagulate water with aluminum sulfate using an anionactive flocculant, for example, during the flood period. Application of coagulation and ultrafiltration units before reverse osmosis installation ensures removing organic impurities from the water. Based on the obtained research results, recommendations are given for the implementation of the results at Ivanovo water treatment plants.
{"title":"Chemical and membrane desalination of natural water with high content of iron-organic compounds","authors":"A. Larin, E. Karpychev, N.N. Yarunina, A.Y. Loginova","doi":"10.17588/2072-2672.2021.6.005-018","DOIUrl":"https://doi.org/10.17588/2072-2672.2021.6.005-018","url":null,"abstract":"Under the conditions of modernization of Russian thermal power plants (TPP), water treatment plants based on imported membrane technologies are often put into operation without consideration of the quality of the source (natural) water and variable-performance operating modes. At the same time long-running water treatment plants and their capabilities are not considered. In this regard, the cost of additional water is three or more times higher, and the average output is respectively lower than at traditional water treatment plants. Often, one doesn’t take the advantages of reverse osmosis installations based on the rejection of the use of aggressive reagents such as sulfuric acid, etc. The aim of the study is to increase the efficiency of desalinated water production. It is especially important to conduct studies of natural waters with high content of iron-organic compounds characteristic of the regions of the center and north of Russia. The authors have carried out laboratory studies of various, primarily new filter materials, regents, and devices, both at the stages of pre-purification of water i.e., clarification, and at the stages of demineralization of clarified water. Water treatment plants of Ivanovo combined-cycle plant (CCP) and Cherepovets state district power station (GRES) are considered as the subject of the research. It is found out that if one applies ion-exchange and membrane water treatment technologies to treat water with high content of iron-organic compounds, high-quality desalinated water can be obtained. The properties of water are the following: specific electrical conductivity of no more than 0,2 mcm/cm and permanganate oxidizability of no more than 1 MgO/l. Results of studies at the Ivanovo CCP and Cherepovets GRES have shown practicability to coagulate water with aluminum sulfate using an anionactive flocculant, for example, during the flood period. Application of coagulation and ultrafiltration units before reverse osmosis installation ensures removing organic impurities from the water. Based on the obtained research results, recommendations are given for the implementation of the results at Ivanovo water treatment plants.","PeriodicalId":23635,"journal":{"name":"Vestnik IGEU","volume":"75 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88538122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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