Експериментальні Дослідження Теплообміну Під Час Глибокого Охолодження Продуктів Згоряння Газоспоживальних Котлів

Navrodska, R. A.; Stepanova, Alla; Shevchuk, Svitlana; Gnedash, Georgii; Presich, Georgii

doi:10.15421/40280620

Cited by 7 publications

(3 citation statements)

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“…Визначення тепловологісних характеристик досліджуваної комплексної теплоутилізаційної системи проводилося за відомими методиками з використанням у конденсаційних режимах роботи розрахункових експериментальних залежностей, отриманих в Інституті технічної теплофізики НАН України [11,12].…”

Section: рис 1 структурна схема комплексної теплоутилізаційної систunclassified

Increase the Efficiency of Complex Heat-Recovery Systems for Heating and Humidifying of Blown Air of Gas-Fired Boilers

Fialko

Presich

Gnedash

et al. 2018

ihe

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The work is devoted to increase of thermal and ecological efficiency of water-heating gas-fired boilers of municipal heat-power engineering. To improve thermal efficiency, heat-recovery technologies are used in which deep cooling of the exhaust-gases from boilers with the realization of the condensation mode of the heat recovery equipment is ensured. To implement this regime throughout the heating period, it is advisable to use complex heat-recovery systems in which several heat transfer agents are heated with sufficiently different thermal potentials. To enhance the environmental effect when using complex systems, it is possible to carry out combustion air humidifying in them, which contributes to the reduction of NOx emissions to the environment by the boiler plants. The work suggests improvement of the known complex heat-recovery system for heating and humidifying the blown air by introducing into its comprise an additional element - water heater of chemical water-purification system. Such the technological solution will ensure a reduction in the thermal losses of the boiler plant and improve the operating conditions of the gas ducts of the boiler house by preventing the condensate from falling out of the wet exhaust-gases. The aim of the work is to investigate the operating parameters of the complex heat-recovery system for heating and humidifying the blown air and preheating the water for chemical water-purification and comparing its basic heatly and humidity characteristics with the corresponding complex system without preheating the water. The results of the investigations are presented in a wide operating range of the load variation of the water-heating boiler respectively the boiler plant temperature graph and are shown graphically. The analysis of the obtained data showed that due to the proposed modernization by preheating the water of the chemical water-purification system in the complex heat-recovery system for heating and humidifying the blown air, an increase of coefficient the use heat of fuel of boilers is provided, depending on their load from 11% to 17%. For this improved heat-recovery system with preheating the water of the chemical water-purification system in comparison with the system without such preheating, the total heating capacity of the complex system increases by 1.3÷1.6 times, and the coefficient the use heat of fuel of the boiler increases by 5.2%.

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Section: рис 1 структурна схема комплексної теплоутилізаційної систunclassified

Increase the Efficiency of Complex Heat-Recovery Systems for Heating and Humidifying of Blown Air of Gas-Fired Boilers

Fialko

Presich

Gnedash

et al. 2018

ihe

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“…Индексы нижние: пот -потери; ст -стенка; вх, вых -вход, выход. стемы использовать параметры, максимально приближенные к оптимальным, что, в свою очередь, увеличивает эффективность системы [1][2][3][4][5][6][7][8][9][10][11][12][13][14].…”

Section: комплексные методики оценки эффективности и оптимизации теплunclassified

Comprehensive Methods of Evaluation of Efficiency and Optimization of Heat-Utilization Systems

Fialko

Stepanova

Shevchuk

et al. 2018

ihe

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At present, Ukraine has the necessary potential for the implementation of effective energy-saving technologies for heat recovery, and therefore the problem of their development and implementation is relevant for the country's energy sector. The solution of this problem is related to the need for systematic studies of the efficiency of optimization of heat recovery facilities from the standpoint of modern methodological approaches. The paper outlines the main stages in the development of integrated methods for assessing the efficiency and optimization of heat recovery systems based on the principles of exergic analysis, statistical methods for planning the experiment, structured variational methods, multilevel optimization methods, the theory of linear systems and the thermodynamics of irreversible processes. Examples and illustrations illustrate some of the stages in the development of complex methods. The necessary general step in the development of methodologies is the development of new performance criteria. Such criteria are highly sensitive to changes in the regime and design parameters of heat recovery systems due to the inclusion of some exergic characteristics in them. The developed criteria also serve as target optimization functions. For individual elements of heat recovery systems, efficiency and optimization methods usually include the definition of the functional dependencies of the selected efficiency criteria on the main parameters. For this, balance methods of exergic analysis and statistical methods of experiment planning are used. If such dependencies are established, optimization is carried out using known mathematical methods. For complex heat recovery systems involving a large number of elements, it is not possible to establish general analytical dependencies of the optimization objective functions on the parameters of the system when constructing mathematical models necessary for their optimization. Complex methods based on the basic principles of structural-variant methods, methods of multilevel optimization, the theory of linear systems, and the thermodynamics of irreversible processes have been developed for such cases. For this purpose, structural diagrams of plants, block diagrams of multi-level optimization have been developed, complete input matrices have been constructed, mathematical models for the processes under investigation have been developed, formulas have been derived for calculating the loss of exergy power in heat conduction processes and formulas for calculating dissipators of exergy. A well-founded choice of the methodology for evaluating efficiency and optimization raises the effectiveness of optimization, since it allows the use of parameters maximally close to optimal when developing the heat recovery system design, which in turn increases the efficiency of the system. References 14, figures 5.

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“…the purpose of this work is to establish patterns of heat transfer in bundles of transversely finned tubes from which water heat exchangers are completed, by conducting experimental studies and determining on their basis the main parameters of the proposed integrated installation. the studies were carried out on the experimental bench, whose scheme, description of work and characteristics of pipes and tube bundles are given in [14]. Data on the main quantities studied on the experimental bench are presented in table 1.…”

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confidence: 99%

Study of Heat Recovery Systems for Heating and Moisturing Combustion Air of Boiler Units

Fialko¹,

Navrodska²,

Gnedash³

et al. 2020

Nauka innov.

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Introduction. One of the ways to save natural gas and to improve the environmental conditions in the municipal heat-power engineering is to use progressive technologies for recovering the heat of flue gases from boiler plants, in which the condensation mode of operation of heat-recovery equipment is implemented. To inc rease the ecological effect in some heat-recovery systems, a humidification process of the combustion air occur. This lowers the combustion temperature of the fuel and reduces the concentration of nitrogen oxides in the combustion products.Problem Statement. At humidifying combustion air, the boiler exhaust-gases are characterized by high moisture content. In the known calculation methods, there are no data on heat transfer under these conditions. This is a problem for conducting thermal calculations of such installations.Purpose. Establishing patterns of heat transfer at an increased moisture content of exhaust-gases in heatrecovery equipment, consisting of bundles of transverse-finned pipes, and determining the main parameters of the proposed complex installation.Materials and Methods. Experimental studies of heat transfer were carried out on a specially created stand. For the thermal and hydraulic calculation of a heat-recovery installation, known calculation methods were used, taking into account the experimental data obtained.Results. The laws of heat transfer during deep cooling of exhaust-gases with moisture content X = 0.15-0.30 kg/kg d.g. are established. The thermal, hydraulic and operating characteristics of the proposed complex heat-recovery installation with heating and humidification of the combustion air in different modes of operation of the boiler are determined. This installation has been introduced; its tests have been carried out, which have confirmed high thermal and environmental efficiency.Conclusions. The application of the proposed complex heat-recovery unit allows increasing the coefficient of the use heat of fuel of boiler depending on its operating mode by 13-20%. K e y w o r d s : heat-recovery of exhaust-gases, increased moisture content, condensation mode, heat-exchange, efficiency use of fuel, and reduction of harmful emissions.

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Експериментальні Дослідження Теплообміну Під Час Глибокого Охолодження Продуктів Згоряння Газоспоживальних Котлів

Cited by 7 publications

References 0 publications

Increase the Efficiency of Complex Heat-Recovery Systems for Heating and Humidifying of Blown Air of Gas-Fired Boilers

Increase the Efficiency of Complex Heat-Recovery Systems for Heating and Humidifying of Blown Air of Gas-Fired Boilers

Comprehensive Methods of Evaluation of Efficiency and Optimization of Heat-Utilization Systems

Study of Heat Recovery Systems for Heating and Moisturing Combustion Air of Boiler Units

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