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Постійне посилання на розділhttps://repository.kpi.kharkov.ua/handle/KhPI-Press/35393
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Документ Improvement of Methods for Calculating Thermal Characteristics of Loop Air Heaters(Технологічний центр, 2021) Yurko, V.; Ganzha, A.; Tarasenko, O.; Tiutiunyk, L.Utilization of heat from gases leaving the waelz process is a promising way to increase its energy efficiency and nvironmental safety. Taking into account the gas dustiness, the most rational is the use of a loop air heater, which is a multi-pass and multi-section heat exchanger with a complex mixed scheme of coolant movement. In modern conditions, when the methods and means of calculation of such devices are simplified, the task of obtaining improved methods and means of calculation, determining the efficiency and reliability of their work is relevant. Two mathematical models of the process of heat transfer and hydroaerodynamics in a multi-pass tubular air heater with a cross-circuit of coolants are used. The developed models for the loop air heater are based on the main methods of thermal calculation: a simpler method of correction factor to the average logarithmic temperature pressure and a discrete P-NTU method, which allows obtaining local thermal characteristics of the surface. Diagrams of distribution of heat transfer coefficients, heat transfer, local temperatures of flue gases, air and pipe walls are constructed. The influence of dust and dust particle size on heat transfer is determined. When the flue gas dust is 50 g/Nm3 and with a dust particle size of 1 μm, the heat transfer coefficient increases by 12 %. The application of the air heater design with different schemes of coolant movement is substantiated. The developed universal methods allow determining the thermal productivity of heat exchangers and obtaining the distribution of local temperature characteristics on the heating surface. It is also possible to identify places of possible overheating of the heat exchange surface and the course of corrosion processes, taking into account the design of recuperators, operating conditions, operating modes and different schemes of coolant movementДокумент Analysis of efficiency and reliability of blast-furnace process waste heat recovery systems(Полтавська державна аграрна академія; НВП ПП "Технологічний Центр", 2017) Ganzha, A.; Zaiets, O.; Koshelnik, A.The object of research is a hot blast generating system, which consists of three hot blast stoves with sequential mode of operation. One of the factors that reduce the hot blast stove block efficiency is the existence of losses with the waste gases, the heat of which can be recovered and used for combustion air preheating. In order to improve the efficiency of a hot blast generating system the possibility of using of recuperative heat exchanger for waste heat recovery is observed. The process of initial parameters determining (the required level of combustion air preheating, waste gases temperature and flow rate at the inlet of the heat exchanger) is described. Software based on using of an original mathematical model and used for calculating of the parameters of the waste heat recovery heat exchanger was created. These data provide tools for refined calculation of heat recovery systems based on recuperative heat exchangers. It is shown that the combustion air preheating results in a reduction of the coke oven gas flow rate. The calculations results in building of temperature distribution diagrams that allow to define the areas of corrosion. Such areas in the observed recuperative heat exchanger model appear at temperatures below 26 °C. Thus, the set approaches can be used to refine the calculation of heat-transfer equipment of waste heat recovery systems to improve their reliability, long life, analyze their technical and economic parameters. This will improve the energy efficiency of the hot blast stoves block and reduce the cost of iron production.