An analysis of modern heat-resistant materials has been carried out, which contain refractory compounds of borides, nitrides, carbides with a limiting melting point of about 2000 °C. New approaches to obtaining heat-resistant materials and the results of studying their structure, phase composition, physical and mechanical properties are shown. For elements of power equipment, an effective and economically sound approach that has a significant effect is the use of heat-resistant coatings. Each heat-resistant covering and technology of its drawing is developed depending on conditions of its use, temperature modes of operation, ergonomic efficiency. The main method of increasing the operating temperature of the ceramic coating layer is to change the chemical composition of the ceramic by introducing an additional number of alloying rare earth elements. An important method of improving the quality of heat-resistant coatings is to optimize the thickness of the ceramic layer and the formation of a barrier microlayer at the interface.
{"title":"HEAT-RESISTANT COATINGS AND PROSPECTS OF THEIR USE FOR PROLONGATION OF THE RESOURCE OF POWER EQUIPMENT (Review).","authors":"S. Kharchenko, S. Kovtun","doi":"10.31472/ttpe.3.2021.10","DOIUrl":"https://doi.org/10.31472/ttpe.3.2021.10","url":null,"abstract":"An analysis of modern heat-resistant materials has been carried out, which contain refractory compounds of borides, nitrides, carbides with a limiting melting point of about 2000 °C. New approaches to obtaining heat-resistant materials and the results of studying their structure, phase composition, physical and mechanical properties are shown. For elements of power equipment, an effective and economically sound approach that has a significant effect is the use of heat-resistant coatings. Each heat-resistant covering and technology of its drawing is developed depending on conditions of its use, temperature modes of operation, ergonomic efficiency. The main method of increasing the operating temperature of the ceramic coating layer is to change the chemical composition of the ceramic by introducing an additional number of alloying rare earth elements. An important method of improving the quality of heat-resistant coatings is to optimize the thickness of the ceramic layer and the formation of a barrier microlayer at the interface.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84773809","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}
The analysis of the methods and equipment in which the heating and melting of hydrocarbon mixtures in the pharmaceutical, food and oil refining industries is carried out has shown that reactors, baths, electric heaters, heating chambers, etc. are traditionally used for heating and melting hydrocarbon mixtures. Such methods are time consuming and energy consuming, large temperature gradients are observed, which leads to overheating of one part of the substance and underheating of another. In addition, the process of loading mixtures into boilers and their subsequent unloading is problematic and unsafe for contamination. Often containers with such substances are kept in unheated or poorly heated rooms (warehouses, workshops, etc.) and are too viscous to be unloaded from the container and transported to the next stages of production, which makes it difficult and slows down their melting. Most of the equipment is purchased abroad, for the purchase of which large funds are spent. The discovered existing problems give impetus to the development of new methods and equipment for the implementation of heating and melting processes. References 6, figures 6.
{"title":"METHODS AND EQUIPMENT FOR HEATING AND MELTING HYDROCARBON MIXTURES IN VARIOUS INDUSTRIES (REVIEW)","authors":"A. Dolinskiy, V. Gorobets, O. Pereiaslavtseva","doi":"10.31472/ttpe.1.2021.2","DOIUrl":"https://doi.org/10.31472/ttpe.1.2021.2","url":null,"abstract":"The analysis of the methods and equipment in which the heating and melting of hydrocarbon mixtures in the pharmaceutical, food and oil refining industries is carried out has shown that reactors, baths, electric heaters, heating chambers, etc. are traditionally used for heating and melting hydrocarbon mixtures. Such methods are time consuming and energy consuming, large temperature gradients are observed, which leads to overheating of one part of the substance and underheating of another. In addition, the process of loading mixtures into boilers and their subsequent unloading is problematic and unsafe for contamination. Often containers with such substances are kept in unheated or poorly heated rooms (warehouses, workshops, etc.) and are too viscous to be unloaded from the container and transported to the next stages of production, which makes it difficult and slows down their melting. Most of the equipment is purchased abroad, for the purchase of which large funds are spent. The discovered existing problems give impetus to the development of new methods and equipment for the implementation of heating and melting processes. \u0000References 6, figures 6.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75270298","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}
Serhii Kostyk, V.Yu. Shybetskyi, S. Plashykhin, Y.О. Bykoriz
Today, heat transfer processes are present in almost all technological processes of various industries. In heat exchange processes, shell-and-tube heat exchangers are quite effective and easy to manufacture, as the long-term practice of using these devices has shown. Therefore, intensification of heat transfer processes, improvement and development of appropriate equipment is a very urgent task. The object of research is a heat-exchange element with special finning on heat-exchange tubes. The subject of research is the heat transfer processes implemented in a heat exchange element with special finning. The aim of the study is to determine the efficiency of heat transfer of the finned surface of the heat exchange element under conditions of forced convection and to evaluate its efficiency by means of experimental and computer research. This article presents a computer simulation that allows to adequately assess the efficiency of using various designs of finning elements of heat exchange equipment. This is confirmed by the convergence of the experimental data and the results of computer simulation (the discrepancy between the results of the experiment and computer simulation does not exceed 5 %). Experimental and computer studies have shown that the proposed technical solution is more effective than standard ones and can be used in the design of new equipment or improvement of the existing one.
{"title":"DETERMINATION OF HEAT TRANSFER EFFICIENCY IN THE CONDITIONS OF FORCED CONVECTION FROM PIPES WITH SPECIAL RIBS","authors":"Serhii Kostyk, V.Yu. Shybetskyi, S. Plashykhin, Y.О. Bykoriz","doi":"10.31472/ttpe.2.2021.3","DOIUrl":"https://doi.org/10.31472/ttpe.2.2021.3","url":null,"abstract":"Today, heat transfer processes are present in almost all technological processes of various industries. In heat exchange processes, shell-and-tube heat exchangers are quite effective and easy to manufacture, as the long-term practice of using these devices has shown. Therefore, intensification of heat transfer processes, improvement and development of appropriate equipment is a very urgent task. The object of research is a heat-exchange element with special finning on heat-exchange tubes. The subject of research is the heat transfer processes implemented in a heat exchange element with special finning. The aim of the study is to determine the efficiency of heat transfer of the finned surface of the heat exchange element under conditions of forced convection and to evaluate its efficiency by means of experimental and computer research. This article presents a computer simulation that allows to adequately assess the efficiency of using various designs of finning elements of heat exchange equipment. This is confirmed by the convergence of the experimental data and the results of computer simulation (the discrepancy between the results of the experiment and computer simulation does not exceed 5 %). Experimental and computer studies have shown that the proposed technical solution is more effective than standard ones and can be used in the design of new equipment or improvement of the existing one.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"32 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72583234","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}
The aim of the work is to carry out a feasibility study of projects for the production of solid biofuels from biomass of pruning of perennial agricultural plantations for further use in boilers. Currently, this bioenergy sector is at the beginning of its development in the EU and in Ukraine, however it has quite good prospects for the future. An assessment of the energy potential of biomass obtained from pruning and removal of orchards and vineyards in Ukraine is performed. According to data of 2019, this potential is estimated at 116.2 ktoe. Though this potential is only a minor part of the total energy potential of biomass in Ukraine (23.6 Mtoe in 2019), biomass of these types is an important local fuel for the regions of its generation and can significantly reduce their dependence on traditional energy carriers. Biomass of pruning and removal of agricultural plantations can be a feedstock for chips (more often for hog fuel) or for solid biofuels of higher quality such as pellets and briquettes. Fuel properties of such solid biofuels are slightly worse than those of biofuels from forest wood or energy crops, but still high enough for the effective use in energy equipment. The main features are higher ash content and, accordingly, lower calorific value. The feasibility study of a typical project for the production of briquettes from vineyard pruning demonstrated economic viability of such projects in Ukraine. Further research in this area will lie in the feasibility study of obtaining solid biofuels from biomass of pruning and removal of orchards, as well as projects for the production of heat from such biofuels for Ukraine’s conditions.
{"title":"FEASIBILITY STUDY OF PROJECTS FOR THE PRODUCTION OF SOLID BIOFUELS FROM BIOMASS OF AGRARIAN PLANTATIONS PRUNING AND REMOVAL","authors":"S. Drahniev, T. Zheliezna, A. I. Bashtovyi","doi":"10.31472/ttpe.2.2021.8","DOIUrl":"https://doi.org/10.31472/ttpe.2.2021.8","url":null,"abstract":"The aim of the work is to carry out a feasibility study of projects for the production of solid biofuels from biomass of pruning of perennial agricultural plantations for further use in boilers. Currently, this bioenergy sector is at the beginning of its development in the EU and in Ukraine, however it has quite good prospects for the future. An assessment of the energy potential of biomass obtained from pruning and removal of orchards and vineyards in Ukraine is performed. According to data of 2019, this potential is estimated at 116.2 ktoe. Though this potential is only a minor part of the total energy potential of biomass in Ukraine (23.6 Mtoe in 2019), biomass of these types is an important local fuel for the regions of its generation and can significantly reduce their dependence on traditional energy carriers. Biomass of pruning and removal of agricultural plantations can be a feedstock for chips (more often for hog fuel) or for solid biofuels of higher quality such as pellets and briquettes. Fuel properties of such solid biofuels are slightly worse than those of biofuels from forest wood or energy crops, but still high enough for the effective use in energy equipment. The main features are higher ash content and, accordingly, lower calorific value. The feasibility study of a typical project for the production of briquettes from vineyard pruning demonstrated economic viability of such projects in Ukraine. Further research in this area will lie in the feasibility study of obtaining solid biofuels from biomass of pruning and removal of orchards, as well as projects for the production of heat from such biofuels for Ukraine’s conditions.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"137 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86615131","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}
The aim of the work is a life cycle assessment of heat production from energy crops by using energy yield coefficient and value of greenhouse gas emissions reduction. State of the art and prospects for growing energy crops in the EU and Ukraine are analyzed. Today, the area under energy crops in the EU and Ukraine is relatively small, but there is significant potential for the development of this sector, which requires further research and implementation of practical measures. Typically, the life cycle assessment of energy production from biomass includes a feedstock cycle, which begins with the phase of biomass collection, and a conversion subsystem. The main feature of the life cycle assessment concerning energy crops is including the phase of their growth in the feedstock cycle. Results of the study show that the energy efficiency of the life cycle of heat production from energy crops chips and pellets is quite high and meets the recommendation that the non-renewable energy yield coefficient should be at least more than 2. Reduction of greenhouse gas emissions during such a life cycle is 40-90% for a 500 kW boiler plant when transporting biofuels to the consumer at a distance of up to 500 km. Feasibility study of projects on growing energy crops and heat production from them shows that under the current conditions in Ukraine, such projects are on the verge of profitability and therefore may not be attractive enough for investors. To promote the development of this sector, it is recommended to introduce a state subsidy per hectare of a plantation area.
{"title":"LIFE CYCLE ASSESSMENT OF HEAT PRODUCTION FROM ENERGY CROPS","authors":"O. Tryboi, T. Zheliezna, A. I. Bashtovyi","doi":"10.31472/ttpe.2.2021.6","DOIUrl":"https://doi.org/10.31472/ttpe.2.2021.6","url":null,"abstract":"The aim of the work is a life cycle assessment of heat production from energy crops by using energy yield coefficient and value of greenhouse gas emissions reduction. State of the art and prospects for growing energy crops in the EU and Ukraine are analyzed. Today, the area under energy crops in the EU and Ukraine is relatively small, but there is significant potential for the development of this sector, which requires further research and implementation of practical measures. Typically, the life cycle assessment of energy production from biomass includes a feedstock cycle, which begins with the phase of biomass collection, and a conversion subsystem. The main feature of the life cycle assessment concerning energy crops is including the phase of their growth in the feedstock cycle. Results of the study show that the energy efficiency of the life cycle of heat production from energy crops chips and pellets is quite high and meets the recommendation that the non-renewable energy yield coefficient should be at least more than 2. Reduction of greenhouse gas emissions during such a life cycle is 40-90% for a 500 kW boiler plant when transporting biofuels to the consumer at a distance of up to 500 km. Feasibility study of projects on growing energy crops and heat production from them shows that under the current conditions in Ukraine, such projects are on the verge of profitability and therefore may not be attractive enough for investors. To promote the development of this sector, it is recommended to introduce a state subsidy per hectare of a plantation area.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80643888","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}
A. Avramenko, N. P. Dmitrenko, Y. Kovetska, O. I. Skitsko
The results of the study of heat transfer under forced convection in a flat porous microchannel taking into account the boundary conditions of slippage of the first and second order are considered. The simulation showed that with decreasing porosity the flow velocity in the central part of the microchannel and the slipping velocity on the wall decrease due to the increase in hydrodynamic resistance. Taking into account the influence of the boundary conditions of the second order shows that the magnitude of the velocity jump on the wall varies depending on the value of the parameter A2. The jump decreases with a positive value of A2, with a negative value - increases in comparison with the case A2 = 0 (first order boundary conditions). Qualitatively similar effects of porosity and second-order boundary conditions were also observed with respect to temperature profiles. The results of the calculation of the relative Nusselt number showed that the decrease in porosity contributes to the intensification of heat transfer. The dynamics of the change in the heat transfer coefficient with an increase in the Knudsen number indicates that an increase in the Prandtl number also leads to an improvement in the thermal interaction of the flow with the channel wall. The analysis of taking into account the boundary conditions of the second order showed that at small values of the Prandtl number (Pr ≤ 1) the influence of the parameter A2 was not observed. At A2 < 0 the effects of the boundary conditions of the second order lead to an increase in the relative Nusselt number, whereas at A2> 0 the value of the normalized Nusselt number decreases in comparison with the case A2 = 0 (boundary conditions of the first order).
{"title":"FEATURES OF HEAT TRANSFER IN A FLAT POROUS MICROCHANNEL WITH THE SECOND ORDER SLIP BOUNDARY CONDITIONS","authors":"A. Avramenko, N. P. Dmitrenko, Y. Kovetska, O. I. Skitsko","doi":"10.31472/ttpe.2.2021.1","DOIUrl":"https://doi.org/10.31472/ttpe.2.2021.1","url":null,"abstract":"The results of the study of heat transfer under forced convection in a flat porous microchannel taking into account the boundary conditions of slippage of the first and second order are considered. \u0000The simulation showed that with decreasing porosity the flow velocity in the central part of the microchannel and the slipping velocity on the wall decrease due to the increase in hydrodynamic resistance. Taking into account the influence of the boundary conditions of the second order shows that the magnitude of the velocity jump on the wall varies depending on the value of the parameter A2. The jump decreases with a positive value of A2, with a negative value - increases in comparison with the case A2 = 0 (first order boundary conditions). \u0000Qualitatively similar effects of porosity and second-order boundary conditions were also observed with respect to temperature profiles. \u0000The results of the calculation of the relative Nusselt number showed that the decrease in porosity contributes to the intensification of heat transfer. \u0000The dynamics of the change in the heat transfer coefficient with an increase in the Knudsen number indicates that an increase in the Prandtl number also leads to an improvement in the thermal interaction of the flow with the channel wall. The analysis of taking into account the boundary conditions of the second order showed that at small values of the Prandtl number (Pr ≤ 1) the influence of the parameter A2 was not observed. At A2 < 0 the effects of the boundary conditions of the second order lead to an increase in the relative Nusselt number, whereas at A2> 0 the value of the normalized Nusselt number decreases in comparison with the case A2 = 0 (boundary conditions of the first order).","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73080854","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}
In recent years, there has been a trend of transition from gas to electric heating, due to changes in the energy sector of the economy. Mass use of portable electric heaters allows to reduce fuel consumption by 25%, significantly reduce heat loss and negative impact on the environment. Electric heating is characterized by affordability, high efficiency, low costs of installation and maintenance, the ability to use preferential tariffs. The purpose of the article is to analyze the technical and economic characteristics and efficiency of typical household electric heaters. The article contains an experimental study of the heat flux and heat of radiation of selected structures. The heat flux density was determined by the calculation method and in comparison with experimental data. Complex heat transfer is taken into account by calculating the heat transfer coefficient. Numerical and experimental study of the natural flow of convection in combination with radiation is carried out with each heated device in the laboratory. A comparative analysis of the ratio of thermal characteristics to the cost and efficiency of devices. With the help of the author's method of "centers of mass" the comparison of qualitative characteristics of devices is carried out. As a result of the analysis it was established that the ALMAZ TERM Panel does not meet the set quality conditions, which requires further refinement of the design and technological indicators. Studies show that it is possible to increase the efficiency of heating devices by increasing the consistency of the temperature profile, changing the radiation factor, optimizing the heat transfer surface of the device, as well as by integrating heat storages to store and improve heat distribution. In this case, the electrical energy is converted into heat and stored with subsequent use during peak hours.
{"title":"RESEARCH OF THERMAL CHARACTERISTICS ELECTRIC HEATING DEVICES","authors":"V. Demchenko, A. Konyk, M. Khomenko","doi":"10.31472/ttpe.2.2021.5","DOIUrl":"https://doi.org/10.31472/ttpe.2.2021.5","url":null,"abstract":"In recent years, there has been a trend of transition from gas to electric heating, due to changes in the energy sector of the economy. Mass use of portable electric heaters allows to reduce fuel consumption by 25%, significantly reduce heat loss and negative impact on the environment. Electric heating is characterized by affordability, high efficiency, low costs of installation and maintenance, the ability to use preferential tariffs. \u0000The purpose of the article is to analyze the technical and economic characteristics and efficiency of typical household electric heaters. The article contains an experimental study of the heat flux and heat of radiation of selected structures. The heat flux density was determined by the calculation method and in comparison with experimental data. Complex heat transfer is taken into account by calculating the heat transfer coefficient. Numerical and experimental study of the natural flow of convection in combination with radiation is carried out with each heated device in the laboratory. \u0000A comparative analysis of the ratio of thermal characteristics to the cost and efficiency of devices. With the help of the author's method of \"centers of mass\" the comparison of qualitative characteristics of devices is carried out. As a result of the analysis it was established that the ALMAZ TERM Panel does not meet the set quality conditions, which requires further refinement of the design and technological indicators. \u0000Studies show that it is possible to increase the efficiency of heating devices by increasing the consistency of the temperature profile, changing the radiation factor, optimizing the heat transfer surface of the device, as well as by integrating heat storages to store and improve heat distribution. In this case, the electrical energy is converted into heat and stored with subsequent use during peak hours.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84800926","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}
A. Avramenko, M. Kovetskaya, E. Kondratieva, T. Sorokina
The paper presents results of the modelling of heat transfer at film boiling of a liquid in a porous medium on a vertical heated wall. Such processes are observed at cooling of high-temperature surfaces of heat pipes, microstructural radiators etc. Heating conditions at the wall were the constant wall temperature or heat flux. An analytical solution was obtained for the problem of fluid flow and heat transfer using the porous medium model in the Darcy-Brinkman. It was shown that heat transfer at film boiling in a porous medium was less intensive than in the absence of a porous medium (free fluid flow) and further decreased with the decreasing permeability of the porous medium. A sharp decrease in heat transfer was observed for the Darcy numbers lower than five. The analytical predictions of heat transfer coefficients qualitatively agreed with the data [14] though demonstrated lower values of heat transfer coefficients for the conditions of the constant wall temperature and constant wall heat flux.
{"title":"HEAT TRANSFER FOR FILN BOILING OF A LIQUID ON A VERTICAL HEATED WALL IN A POROUS MEDIUM","authors":"A. Avramenko, M. Kovetskaya, E. Kondratieva, T. Sorokina","doi":"10.31472/ttpe.1.2021.3","DOIUrl":"https://doi.org/10.31472/ttpe.1.2021.3","url":null,"abstract":"The paper presents results of the modelling of heat transfer at film boiling of a liquid in a porous medium on a vertical heated wall. Such processes are observed at cooling of high-temperature surfaces of heat pipes, microstructural radiators etc. Heating conditions at the wall were the constant wall temperature or heat flux. \u0000An analytical solution was obtained for the problem of fluid flow and heat transfer using the porous medium model in the Darcy-Brinkman. It was shown that heat transfer at film boiling in a porous medium was less intensive than in the absence of a porous medium (free fluid flow) and further decreased with the decreasing permeability of the porous medium. A sharp decrease in heat transfer was observed for the Darcy numbers lower than five. The analytical predictions of heat transfer coefficients qualitatively agreed with the data [14] though demonstrated lower values of heat transfer coefficients for the conditions of the constant wall temperature and constant wall heat flux.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"2010 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86291393","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}
In sewage treatment plants, sludge is formed during wastewater treatment, in addition to treated water. They are dumped on silt sites, which occupy large areas and almost all overcrowding. The content of large amounts of minerals and toxic substances in sediments leads to the deterioration of underwater waters and land, which in turn leads to the deterioration of ecology and life in Ukraine. An urgent task in Ukraine is to create a comprehensive processing of sludge, which includes economic, technological, social and environmental aspects. The main methods of sludge disposal are use in agriculture, landfilling, incineration and dumping into the sea or ocean. The country is gradually trying to abandon the burial. European Union countries also process sludge aerobically and anaerobically. During these processes, components of organo-mineral fertilizers are created that can be used in agriculture. As fertilizers, sludge is composted, stabilized and pasteurized. Combustion of sludge allows to obtain a substitute for coal and oil. To increase the heat of combustion and improve combustion parameters to sludge sludge add coal, biomass. Low-temperature pyrolysis of sewage sludge and household waste, which allows to obtain "crude oil". One of the methods is processing in biogas plants to obtain both biogas and environmentally friendly fertilizers. To increase the efficiency of treatment and reduction of sludge disposal of used stagnation-ments vermiculture. Analysis of the literature allows us to conclude that there are methods of disposal of sludge, which have become widespread in various countries around the world, such as fertilizers, alternative fuels, landfills and others. When disposing of sludge, it is possible to produce biogas, electricity and heat, which reduces energy costs for the process.
{"title":"STATE OF WASTEWATER TREATMENT TECHNOLOGIES IN UKRAINE AND THE WORLD","authors":"S. Yu, Zh. A. Petrova, V. Paziuk, Yu.P. Novikova","doi":"10.31472/ttpe.1.2021.1","DOIUrl":"https://doi.org/10.31472/ttpe.1.2021.1","url":null,"abstract":"In sewage treatment plants, sludge is formed during wastewater treatment, in addition to treated water. They are dumped on silt sites, which occupy large areas and almost all overcrowding. The content of large amounts of minerals and toxic substances in sediments leads to the deterioration of underwater waters and land, which in turn leads to the deterioration of ecology and life in Ukraine. An urgent task in Ukraine is to create a comprehensive processing of sludge, which includes economic, technological, social and environmental aspects. \u0000The main methods of sludge disposal are use in agriculture, landfilling, incineration and dumping into the sea or ocean. The country is gradually trying to abandon the burial. European Union countries also process sludge aerobically and anaerobically. During these processes, components of organo-mineral fertilizers are created that can be used in agriculture. As fertilizers, sludge is composted, stabilized and pasteurized. Combustion of sludge allows to obtain a substitute for coal and oil. To increase the heat of combustion and improve combustion parameters to sludge sludge add coal, biomass. Low-temperature pyrolysis of sewage sludge and household waste, which allows to obtain \"crude oil\". One of the methods is processing in biogas plants to obtain both biogas and environmentally friendly fertilizers. To increase the efficiency of treatment and reduction of sludge disposal of used stagnation-ments vermiculture. \u0000Analysis of the literature allows us to conclude that there are methods of disposal of sludge, which have become widespread in various countries around the world, such as fertilizers, alternative fuels, landfills and others. When disposing of sludge, it is possible to produce biogas, electricity and heat, which reduces energy costs for the process.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"7 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91509804","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}
The aim of the work is to identify promising areas of research in bioenergy to expand potential types of technologies and sectors for the implementation of bioenergy projects in Ukraine. Current research topics of the Bioenergy Program of the International Energy Agency are analyzed, and some of the obtained results are considered. Special attention in the studies within the Program is paid to the issues of sustainable development, decarbonization of energy, and circular economy. The results of almost all the studies are important and relevant for Ukraine. They show promising areas for further research and development, as well as help to identify new types of potential bioenergy projects. At present, Ukraine has already implemented a large number of bioenergy projects in the industry at enterprises that have biomass raw materials as a by-product of the main production. Examples of such enterprises are oil extraction plants, sugar factories, woodworking enterprises. But there are many companies not provided with their own biomass that would like to reduce their carbon footprint by switching to renewable energy. Technical and organizational solutions for mobilizing biomass for energy studied within the IEA Bioenergy’s inter-task project “Bioenergy for high temperature heat in industry” may be very useful to these enterprises.
{"title":"OVERVIEW OF CURRENT DIRECTIONS OF RESEARCH BY THE INTERNATIONAL ENERGY AGENCY IN THE BIOENERGY SECTOR","authors":"T. Zheliezna, A. I. Bashtovyi","doi":"10.31472/ttpe.1.2021.7","DOIUrl":"https://doi.org/10.31472/ttpe.1.2021.7","url":null,"abstract":"The aim of the work is to identify promising areas of research in bioenergy to expand potential types of technologies and sectors for the implementation of bioenergy projects in Ukraine. Current research topics of the Bioenergy Program of the International Energy Agency are analyzed, and some of the obtained results are considered. Special attention in the studies within the Program is paid to the issues of sustainable development, decarbonization of energy, and circular economy. The results of almost all the studies are important and relevant for Ukraine. They show promising areas for further research and development, as well as help to identify new types of potential bioenergy projects. At present, Ukraine has already implemented a large number of bioenergy projects in the industry at enterprises that have biomass raw materials as a by-product of the main production. Examples of such enterprises are oil extraction plants, sugar factories, woodworking enterprises. But there are many companies not provided with their own biomass that would like to reduce their carbon footprint by switching to renewable energy. Technical and organizational solutions for mobilizing biomass for energy studied within the IEA Bioenergy’s inter-task project “Bioenergy for high temperature heat in industry” may be very useful to these enterprises.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91208067","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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