The operation efficiency analysis of the modernized DP-500 deaerator of the 300 MW power unit at the Trypillia TPP.
Students Name: Kocheharov Vasyl
Qualification Level: magister
Speciality: Heat and Power Engineering
Institute: Institute of Power Engineering and Control Systems
Mode of Study: part
Academic Year: 2022-2023 н.р.
Language of Defence: ukrainian
Abstract: Kocheharov V. O., Rymar T. I. (supervisor). The operation efficiency analysis of the modernized DP-500 deaerator of the 300 MW power unit at the Trypillia TPP. Master’s thesis. – Lviv Polytechnic National University, Lviv, 2022. Extended abstract Thermal deaeration of water is the main method of combating internal corrosion of the steam-water path of TPP energy equipment, as well as pipelines and heat exchange equipment of heat supply systems. Thermal deaeration is a process of gas desorption, during which the dissolved gas changes from a liquid to a vapor that is in contact with it. It is known [1, 2] that carbon dioxide and oxygen, soluble in feed water, which is used to feed boilers, contribute to the corrosion of structural materials. Carbonic acid does not directly cause corrosion, but its presence activates this process. The presence of oxygen in water affects the process of electrochemical corrosion and accelerates it. The presence of oxygen, carbon dioxide, as well as other gases in the feed water is extremely undesirable, therefore more complete deaeration of the feed water is necessary. Metal corrosion leads to a decrease in the power of the equipment, its breakdown, and as a result to emergency shutdowns, a decrease in the production of thermal and electrical energy, to the idling of the equipment, which negatively affects the operation of the station as a whole and leads to a decrease in its competitiveness on the wholesale market of electrical energy and power. One of the main reasons for the formation of corrosion at TPPs is the presence in the cycle of water containing oxygen, carbon dioxide, acids, alkalis, chlorides, sulfates, which, together with work at high temperatures and pressure, puts a huge load on the metal of the equipment, pipes, and fittings. However, this is not the only cause of corrosion of TPP equipment [3, 4]. Therefore, research using models and methods for calculating the efficiency of water purification devices from dissolved gases, as well as scientific and technical solutions for modernization, are relevant for TPPs. Study object – the deaeration unit of the 300 MW Trypil TPP power unit. Scope of research – methodical approaches to solving the problems of calculation justification of increasing the efficiency of the modernized DP-500 deaerator of the 300 MW power unit of the Trypil TPP based on the methodology of calculating the bubbling area of the deaeration column using mathematical modeling methods. Goal of research: development of scientific and technical solutions to increase the efficiency of thermal deaerators at TPPs based on the method of calculating the bubbling area of the deaeration column using mathematical modeling methods. Objectives of the study: - Development of scientific and technical solutions to increase the efficiency of thermal deaerators at the TPP based on the determination of the parameters of the bubbling area of the deaeration column. – Thermal, structural, verification calculation of the dimensions of the active zone of the deaeration column for the high-pressure deaerator DP-500. – Developments to improve the performance of the high-pressure thermal deaerator for the 300 MW TPP power unit. Scientific novelty of the results of the master’s qualification work: analysis of the operation of the deaerator in the nominal mode; analysis of the operation of the deaerator in the mode with a reduced load; analysis of the operation of the deaerator in the mode of increased load; analysis of the development of a high-pressure thermal deaerator for a power unit with a capacity of 300 MW TPP; calculation and experimental studies of thermal schemes for connecting the DP-500 deaerator to other devices. The main method of removing dissolved gases from water, which is used at TPPs, is thermal deaeration, which is the resulting process of predominance of the mass rate of desorption (the process of releasing dissolved gas from a solution) over absorption (the process of gas absorption by a liquid absorber) for the efficiency and long-term equipment of TPPs. In the master’s thesis, an improved version of the deaeration scheme of the feed water for thermal networks of thermal power plants is proposed, which makes it possible to ensure the normative quality of water based on the regulation of the consumption of the heating agent and the temperature of the water before the deaerator. Comprehensive adjustment of the mode parameters of the deaeration unit ensures the absence of internal corrosion of the structural materials of the equipment and pipelines. The method of calculating the dimensions of the active zone of the deaeration column for the high-pressure deaerator DP-500, which ensures obtaining water at the exit from the column with the required concentration of oxygen and carbon dioxide, is proposed. In the end, the calculation results make it possible to increase the efficiency of the DP-500 deaeration column. The active zone of the deaeration column is the bubbling layer of water in the bubbling plate, where water is actively bubbled by the steam entering through the holes in this plate. Keywords: thermal deaeration, deaeration column, oxygen concentration, diffusion, internal corrosion. References 1. Hlushchenko, O. & Rudenko, К. (2022). Research of deaeration and nutritional installation operation in ordar to determine its optimal and most efficient operating mode. S World Journal, 1 (11 – 01), рр. 17 – 22. https://doi.org/10.30888/2663-5712.2022-11-01-016 2. Hlamazdin, P. M., Taradai, O. M. & Fomich, S. Y. (2016) Possibilities of reducing the emergency of centralized hot supply networks by deaeration of water. Scientific and technical collection «Ventilation, lighting and heat and gas supply». vol. №19. – К.: KNUBA, рр. 117 – 125. 3. Pazushkyna, O. V., Zolyn, M. V. & Sylkyn, Y. A. (2022). Analysis of the operation of deaeration devices at a production boiler house. News of higher educational institutions. ENERGY PROBLEMS. Т. 24. № 1. рр. 99 – 113. doi:10.30724/1998- 9903-2022-24-1-99-113. 4. Petrash, R. I. & Hlamazdin, P. M. (2014). Economic aspects of replacing vacuum deaeration of mains water with chemical deaeration // Zhytlovo-komunalne hospodarstvo Ukrainy. – №3 – рр. 46 – 47.