Visnik Natsional''nogo tekhnichnogo universitetu Ukrayini <> Seriia <>最新文献

{"title":"Use of flocculants in processes water softening","authors":"Kateryna Hordiienko, Yaroslav Radovenchyk","doi":"10.20535/2617-9741.3.2023.288254","DOIUrl":"https://doi.org/10.20535/2617-9741.3.2023.288254","url":null,"abstract":"Deterioration of the quality of natural waters every year causes increasing concern of specialists and ordinary citizens. The shortage of water in certain regions and the disappointing forecasts for the supply of water for humanity in the future transfer the problems of the hydrosphere into the category of catastrophic. Mineralization of natural waters as a result of anthropogenic and natural factors is one of the most acute problems of water supply today. Water softening by removing calcium and magnesium ions allows you to partially solve this problem. Today, reactive methods of softening, in which phosphates are used as a precipitant, are able to form compounds with calcium and magnesium ions that are poorly soluble in water. Due to the high dispersion of solid phase particles formed as a result of such processing, there are problems of effective separation of liquid and solid phases. The use of flocculants makes it possible to intensify the filtering process, prevent clogging of the filter pores with solid particles, and reduce the duration of the technological process. During the research, we studied the effect on phase separation of different types of flocculants - polyacrylamide - as a nonionic flocculant, Magnofloc - 336 from Ciba - as an anionic flocculant, Zetag - 7692 from Ciba - as a cationic flocculant. The model solutions contained approximately equal amounts of calcium and magnesium ions with a total hardness of 27 mg-eq/dm3 and were treated with an equivalent amount of sodium phosphate mixed with a flocculant dose of 1 – 80 mg/dm3. Conducted studies have shown that the addition of polyacrylamide in concentrations of 1 - 10 mg/dm3 is not accompanied by a positive effect during advocacy. After settling for 1 hour, the apparent volume of the solid phase is 30-40 % higher than the similar indicator without flocculant treatment. A noticeable effect is observed only at flocculant doses of 30 - 80 mg/dm3. Moreover, in the latter case, illumination occurs quite quickly and within 10 min the imaginary volume of the solid phase reaches its minimum and changes very little during further settling. During filtration, the addition of a flocculant only slows down the process of separating the solid phase and significantly prolongs the production of a softened liquid phase. Addition of flocculant even in concentrations of 1 mg/dm3 negatively affects the parameters of the filtration process. Therefore, it is possible to unequivocally state that polyacrylamide cannot be used as an intensifier of the phase separation process for systems of low and medium productivity (in which it is intended to use filtering). Under the same conditions, the efficiency of Magnofloc - 336 anionic flocculant during sedimentation is somewhat higher compared to polyacrylamide. At a flocculant dose of 30-80 mg/dm3, the bulk of the solid phase settles within 5 minutes and forms a volume of about 30 cm3. Without a flocculant, softened water of such hardness clears very slowl","PeriodicalId":33504,"journal":{"name":"Visnik Natsional''nogo tekhnichnogo universitetu Ukrayini <> Seriia <>","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135032747","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}

{"title":"Development of a spray dryer’s mathematical model for control tasks","authors":"Oleksii Sytnikov, Denys Skladannyy, Kostiantyn Sokolov","doi":"10.20535/2617-9741.3.2023.288249","DOIUrl":"https://doi.org/10.20535/2617-9741.3.2023.288249","url":null,"abstract":"The sustainable development paradigm includes the most efficient material and energy resources using in production processes. One of the ways to achieve this goal is creating the effective automated control systems. At the same time, such systems effective functioning is impossible without adequate mathematical models for control objects. Thus, the actual task of this study is to create the control object – a spray dryer -model-, which could be used in the control system.&#x0D; It was established that one of the main devices in the sodium tripolyphosphate production is a spray dryer in which the aqueous salts suspension is dried by flue gases. The obtained powdery product which is fed into the calcination furnace. The work investigated convective drying, where the material is in direct contact with the drying agent – furnace gas. To drying process control by the drying agent temperature.&#x0D; The existing works analysis showed that the mathematical model developing process of a spray dryer requires in-depth research into the physical nature of processes which taking object's operation’s various factors into account. The object presentation can be carried out with different approaches taking into account various important production factors, but at the same time it should be as close as possible to the nature of process. The development of the spray drying process model is carried out for regulation the moisture at the finished product.&#x0D; The beginning of the research is the structural and parametric diagram creation of a spray dryer taking into account all input and output values which allow to determine the control disturbance channels. A material balance based on the moisture and loose matter amount and a gas environment heat balance is compiled. The transfer functions component calculation is carried out using the Kramer method. &#x0D; The presented results of the research make it possible to build and analyse the spray dryer mathematical model taking into account the requirements for the substance moisture content be dried and the control process analysis by the drying agent temperature changing. The transient characteristics of the spray dryer by the disturbance and control channels, which are calculated and presented in the research make it possible to compare the control object behaviour with and without taking heat loss into the environment the assumptions into account.","PeriodicalId":33504,"journal":{"name":"Visnik Natsional''nogo tekhnichnogo universitetu Ukrayini <> Seriia <>","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135032403","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}

{"title":"External removable elements of pipes for heat transfer enhancement (Design overview)","authors":"Іhor Mikulionok, Anton Karvatskii, Olena Ivanenko, Serhii Leleka","doi":"10.20535/2617-9741.3.2023.288246","DOIUrl":"https://doi.org/10.20535/2617-9741.3.2023.288246","url":null,"abstract":"The subject of the study is the external removable means of heat exchange pipes for intensifying the heat exchange process in technological equipment and pipelines of various sectors of the economy.&#x0D; Studies of the state of art and prospects of constructive and technological design of external removable elements of pipes for heat transfer intensification are based on a critical analysis of scientific and technical sources of information and, above all, patent information from the leading countries of the world, since it is in the patent documentation that information is provided on innovative developments in the relevant field of technology and technology.&#x0D; With the help of methods of analysis and synthesis, external removable elements of pipes for the intensification of heat transfer of equipment and pipelines in the chemical and related branches of technology are systematized. For each type of elements, a detailed classification has been developed, on the basis of which the most interesting designs proposed by scientists, designers and inventors of the leading countries of the world are considered. A critical assessment is given to most of the elements, an analysis of their advantages and disadvantages is made. Preference is given to sources of information from the end of the second and beginning of the third millennium.&#x0D; The designs of these elements are analyzed depending on the regime of the fluid coolant, the presence of a change in the state of aggregation of the coolant, the nature of the effect on the flow over time, the nature of the change in the flow hydrodynamics, the degree of change in the flow hydrodynamics, the relative length, the orientation of the pipes in space, the degree of the channel curvature, the material, the degree of assembly , the degree of mobility of the components, the number of covered pipes, as well as the type of blank. It is shown that, despite a significant variety of designs of external removable elements of pipes for heat transfer intensification, metal plate elements tested in manufacture and operation remain the most in demand by the industry. However, due to the advances in materials science and computer modeling, the search for new designs of pipe elements to intensify heat transfer continues.","PeriodicalId":33504,"journal":{"name":"Visnik Natsional''nogo tekhnichnogo universitetu Ukrayini <> Seriia <>","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135032563","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}

{"title":"Evaluation of the electroflotation efficiency for the oil-containing shipping waters treatment","authors":"Marta Vozniuk, Tetiana Shabliy","doi":"10.20535/2617-9741.3.2023.288252","DOIUrl":"https://doi.org/10.20535/2617-9741.3.2023.288252","url":null,"abstract":"The article describes the problems of formation and purification of ship oil-containing waters. The effectiveness of electroflotation using aluminum and iron anodes for the extraction of oil from water-oil emulsions with different mineralization was assessed.&#x0D; Electroflotation treatment of water-oil solutions provides 98.6–99.9 % oil removal using aluminum or iron electrodes at an anodic current density of 1.65–7.39 A/dm2 for highly mineralized waters and 0.07–0.50 A/dm2 for fresh water.&#x0D; Water treatment during the first 15 minutes provides a sharp decrease in oil content from 100 mg/dm3 to 1.31–2.52 mg/dm3, almost regardless of the type of anode metal. The efficiency of oil extraction from water mainly depends on its mineralization. In mineralized (salty) water, the treatment process is more efficient. In fresh waters, aluminum anode provides higher water purification efficiency compared to iron anode. However, in the case of pre-treatment of the iron anode with an alkali solution with the formation of a magnetite layer on it, this anode is characterized by the highest purification efficiency for low-salt waters, providing a degree of water purification at the level of 99.9 %.","PeriodicalId":33504,"journal":{"name":"Visnik Natsional''nogo tekhnichnogo universitetu Ukrayini <> Seriia <>","volume":"409 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135032750","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}

{"title":"Simulation of a shell-tube heat exchanger in the oil and gas industry","authors":"Serhii Kubakh, Vitalii Tsapar","doi":"10.20535/2617-9741.3.2023.288245","DOIUrl":"https://doi.org/10.20535/2617-9741.3.2023.288245","url":null,"abstract":"From the analysis of available literary sources, it follows that the most effective way of introducing heat exchangers into production processes is by using computational fluid dynamics (CFD) modeling. This method also involves fine-tuning the components from which the model is formed. Energy efficiency, safety, and stable functionality of units are key aspects of production activities. CFD modeling provides ample opportunities for studying heat exchange processes in thermal installations, such as tubular heat exchangers. Optimizing the operation of such systems implies careful adjustments, including creating a three-dimensiona l model taking into account real dimensions, and flexible adjustment of various flow regimes and thermal conditions. &#x0D; Process flow heating and cooling processes are standard practice in various industries. These operations are often performed in heat exchangers where the fluid flows through tubes in laminar conditions. Heat transfer mechanisms in such conditions are complex and not yet fully explored, as they include both forced and natural convection. This creates difficulties in accurately predicting the design of the heat exchanger. The use of simplified geometric models and limited information about oil refining processes in computer simulations significantly affects the analysis and optimization possibilities. This approach can significantly accelerate the development of new types of heat exchangers. Current research emphasizes design changes to improve heat transfer and other performance. &#x0D; Previous studies note a lack of specific recommendations for design improvement, incomplete investigation of the causes of inaccurate results, and insufficient detail of important parameters. This study presents the model setup steps with emphasis on the important details of the heat exchanger. The grid adjustment process and the properties of the incoming oil are described. The impact of turbulence on crude oil and steam temperature changes is considered. The influence of speed on the heat exchange coefficient was also analyzed in detail, and prospects for further optimization were determined. The application of computer modeling in the oil and gas industry is important. It is a key tool for improving the efficiency, security, and sustainability of operations in the industry. &#x0D; Computer modeling allows you to predict and optimize processes, create accurate virtual models of objects, analyze their security, and research new technologies. It also facilitates economic analysis, staff training, and innovation. As a result, computer simulation improves decisions, reduces risks, and promotes the development of the entire oil and gas industry. It is one of the effective methods of studying physical systems. Often, computer models are easier and more convenient to study, they allow conducting computational experiments, the real setting of which is difficult or can give an unpredictable result. All these aspects together a","PeriodicalId":33504,"journal":{"name":"Visnik Natsional''nogo tekhnichnogo universitetu Ukrayini <> Seriia <>","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135032051","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}

{"title":"Control of oils and greases adsorptive recovery in conditions of non-stationarity","authors":"Liudmyla Yaroshchuk, Yevheniia Tiurina","doi":"10.20535/2617-9741.3.2023.288251","DOIUrl":"https://doi.org/10.20535/2617-9741.3.2023.288251","url":null,"abstract":"In various fields of production and transport, the demand for oils and greases, which are complex substances harmful to the environment, is constantly growing, and their production requires significant financial costs.&#x0D; An actual task is the creation of control systems for adsorptive purification of used oils and greases, which will be able to meet the requirements of their regeneration quality in conditions of insufficient information provision and non-stationarity of a significant number of characteristics of the technological system.&#x0D; The analysis of properties of raw materials, adsorbent and adsorber from the point of view of the necessary and potentially possible information support was carried out.&#x0D; Three main sources of non-stationarity are singled out: periodic arrival of raw material with new properties; random changes in properties of current raw materials and adsorbent; gradual changes of the working surfaces of the adsorber due to interaction with adsorbent and adsorbate. The first source is recognized as the most significant, therefore, two components are provided for the general control algorithm – control in the modes of variable and stable raw materials (significant and non-significant changes in properties of raw materials, respectively).&#x0D; For each source of non-stationarity, a corresponding adaptation block for pressure and temperature control systems in adsorber with PI-controllers is proposed. The properties of the substances that will be used to correct controllers tasks and their setting parameters have been determined. A system of individual adaptation blocks interaction in both modes of the general control algorithm has been created.&#x0D; For the stable raw materials mode, general view of transfer functions for control channels is given and the adaptive control system structure is proposed with implementation of current identification of the control channel model and calculation of the corresponding PI-controllers setting parameters.&#x0D; The obtained results will allow to reduce duration and amplitudes of quality indicators deviations of regenerated substances from the set values, which will increase control system efficiency as a whole. The proposed methods can be applied to those technologies where there is a problem of stabilizing properties of input material flows, in particular, in technologies using secondary raw materials.","PeriodicalId":33504,"journal":{"name":"Visnik Natsional''nogo tekhnichnogo universitetu Ukrayini <> Seriia <>","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135032748","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}

{"title":"Use of heat recovery technology to increase thermal efficiency of rotary furnaces","authors":"Valerii Shcherbina, Olena Ivanenko, Oleksandr Sokolskyi, Gennady Vasilchenko","doi":"10.20535/2617-9741.3.2023.288247","DOIUrl":"https://doi.org/10.20535/2617-9741.3.2023.288247","url":null,"abstract":"The article considers the problem of increasing the energy efficiency of rotary kilns, which are used in various industries for thermal processing of materials, such as metallurgical, chemical, construction, electrode and others. The source of heat for the kilns is gaseous fuel, which is supplied through special burners located at one end of the cylinder. The material for processing is loaded at the opposite end and moves towards the burner due to the force of gravity and rotation of the kiln. One of the important aspects of operating rotary kilns is energy efficiency, which depends on many factors and generally characterizes the degree of use of heat from fuel for heating the material. However, a significant part of the heat from fuel is lost through the kiln shell, which leads to an increase in fuel consumption and a decrease in kiln productivity. Therefore, it is necessary to look for ways to reduce heat losses and use part of the heat for other purposes. In this context, heating secondary air can be one of the important methods for increasing the thermal efficiency of rotary kilns, especially for kilns that operate in a mode for pyrolysis firing of materials such as coal, wood, peat, etc. The aim of the work is to increase the energy efficiency of a rotary kiln using a spiral heat exchanger, using the heat from the external shell of the kiln to heat secondary air. The paper proposes the use of a sectional heat exchanger, which can perform the functions of a cooler, a thermal insulator and a regulator of temperature regimes of the kiln. The heat exchanger consists of several sections that are attached to the outer surface of the kiln shell and have channels for air passage. The air is heated by contact with the hot shell and then supplied to the burner as secondary air. Thus, the heat exchanger allows to reduce the temperature of the shell and provide an additional source of hot air. A mathematical model for numerical calculation of a spiral heat exchanger has been developed, which allows to evaluate its thermal and temperature characteristics. It is shown that by using the heat from the shell it is possible to heat secondary air to a temperature of 270 °C in an amount sufficient to ensure the operation of the burner. An analysis of the location of the heat exchanger and the use of insulation coating has been carried out, which made it possible to significantly reduce its size without changing the total thermal effect compared to a heat exchanger installed along the entire length of the kiln shell. The effectiveness of using thermal insulation has been shown, which makes it possible to increase the temperature of air by 50 °C with its thickness 7 mm. The obtained results can be useful for further development and optimization of projects aimed at improving heat exchange systems and efficient use of thermal resources in rotary kilns.","PeriodicalId":33504,"journal":{"name":"Visnik Natsional''nogo tekhnichnogo universitetu Ukrayini <> Seriia <>","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135032749","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}

{"title":"Concentration of sodium chloride solutions in the processing of concentrates for reverse osmotic water desalification","authors":"Mykola Gomelya, Yana Kryzhanovska","doi":"10.20535/2617-9741.3.2023.288253","DOIUrl":"https://doi.org/10.20535/2617-9741.3.2023.288253","url":null,"abstract":"The paper examines the processes of concentrating sodium chloride solutions by the electrodialysis method. Given the shortage of reagents and their high prices, this electrodialysis method can be implemented to obtain acid and alkali from solutions of sodium sulfate, alkali, aluminum and iron coagulants. Today, the technologies that, as a result of the process, allow us to obtain valuable materials, substances, products, coagulants as a secondary product, are very justified, economically feasible and, most importantly, allow us to successfully implement the principles of low-waste production. The essence of the process is the use of sodium chloride solutions, which are formed during the desalination of water by reverse osmosis in the form of concentrates. The concentration process was implemented in a three-chamber electrolyzer, in the cathode, anode and working areas, a sodium chloride solution with a concentration of 360 mmol/dm3 was placed. An alkali solution with a concentration of 480 mg-eq/dm3 was used in the anode area. During electrolysis, alkali was formed in the cathode area, due to the diffusion of sodium in the working area and the cathodic reduction of water. Chlorides from the working area moved to the anode area. Hydroxide anions on the anode were oxidized to oxygen, chlorides with sodium formed sodium chloride, the concentration of which increased to 660 mg-eq/dm3. Alkalinity decreased to 68-70 mg-eq/dm3. When changing cathodes and anodes, the process was repeated in some places until the alkalinity in the cathode zone and the concentration of chlorides in the anode zone increased. . A solution of sodium chloride with a concentration of 360 mmol/dm3 was added to the working area where water desalination took place. After nine cycles of electrolysis, a sodium chloride solution with a concentration of 100-150 g/dm3 was obtained. The residual content of sodium chloride in desalinated water reached 50-100 mg/dm3. Sodium chloride solutions with a concentration of 4 to 30 g/dm3 can be used for concentration. It should be noted that after conducting nine cycles of the experiment, we can state that the process of concentration by this electrodialysis method does not lead to an increase in system resistance and energy consumption.","PeriodicalId":33504,"journal":{"name":"Visnik Natsional''nogo tekhnichnogo universitetu Ukrayini <> Seriia <>","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135032401","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}