Efficiency of the air heater in a heat recovery system at different thermophysical parameters and operational modes of the boiler
DOI:
https://doi.org/10.15587/1729-4061.2018.147526Keywords:
loss of exergetic power, thermophysical exergetic parameters, heat transfer processes, boiler’s operational modesAbstract
We have examined, for the plate heater included in a heat recovery system of the boiler plant, the influence of its thermophysical parameters on the losses of exergetic power under different operational modes of the heating boiler. A procedure for the calculation of losses in a given heat recovery unit is based on an integrated approach that combines exergetic methods with the methods of thermodynamics of irreversible processes. A mathematical model includes a differential equation of the exergy balance and an equation of thermal conductivity for an air heater under boundary conditions of the third kind. The differential equation of exergy balance has been solved jointly with the equation of thermal conductivity. The result of solving them is the obtained estimation dependences for determining the losses of exergetic power associated with the processes of heat transfer.
We have calculated losses of exergetic power in the examined heat recovery units at a change in the coefficient of thermal conductivity of the plate, in the heat transfer coefficient from flue gases and an operational mode of the boiler. The derived dependences on a thermal conductivity coefficient for the considered operating modes of the boiler have two distinct sections, along the first of which there is a relatively small increase in the losses of exergetic power while reducing the coefficient of thermal conductivity, along the second ‒ the loss of exergetic power in a heat recovery unit increase relatively sharply. For the considered sequence of regimes of the boiler a transition from its maximum heat output to the minimal one is accompanied by a decrease in the losses of exergetic power. A similar character is also demonstrated by the dependence on a thermal conductivity coefficient of the relative contribution of losses of exergetic power in the heat transfer processes to their totals in a heat recovery unit. In this case, there are minor differences in the relative contribution of these losses under different operational modes of the boiler. The heat transfer coefficient from the side of flue gases within a framework of a single operating mode of the boiler affects less significantly, compared to the thermal conductivity coefficient of the material of a heat exchange surface, the losses of exergetic power in the heat transfer processes. We have established regions of change in the thermal conductivity coefficient, as well as operational modes of the boiler, in the range of which the losses of exergetic power in a heat recovery unit are minimalReferences
- Sahin, A. Z. Importance of Exergy Analysis in Industrial Processes. Available at: https://www.researchgate.net/publication/228988818
- Hajjaji, N., Pons, M.-N., Houas, A., Renaudin, V. (2012). Exergy analysis: An efficient tool for understanding and improving hydrogen production via the steam methane reforming process. Energy Policy, 42, 392–399. doi: https://doi.org/10.1016/j.enpol.2011.12.003
- Cziesla, F., Tsatsaronis, G., Gao, Z. (2006). Avoidable thermodynamic inefficiencies and costs in an externally fired combined cycle power plant. Energy, 31 (10-11), 1472–1489. doi: https://doi.org/10.1016/j.energy.2005.08.001
- Jiang, Y. Y., Zhou, S. X. (2010). Exergy Analysis of Boiler Based on the Temperature Gradient. 2010 Asia-Pacific Power and Energy Engineering Conference. doi: https://doi.org/10.1109/appeec.2010.5449523
- Tsatsaronis, G., Morosuk, T. (2012). Advanced thermodynamic (exergetic) analysis. Journal of Physics: Conference Series, 395, 012160. doi: https://doi.org/10.1088/1742-6596/395/1/012160
- Morosuk, T., Tsatsaronis, G. (2008). A new approach to the exergy analysis of absorption refrigeration machines. Energy, 33 (6), 890–907. doi: https://doi.org/10.1016/j.energy.2007.09.012
- Fialko, N., Stepanova, A., Presich, G., Gnedash, G. (2015). The efficiency analisis of heat utilization instalasion for heating and humidifying of combustion air of boiler plant. Industrial Heat Engineering, 37 (4), 71–79. Available at: http://dspace.nbuv.gov.ua/bitstream/handle/123456789/142191/08-Fialko.pdf?sequence=1
- Fialko, N., Stepanova, A., Navrodskaya, R., Sherenkovsky, J. (2014). Efficiency for heat utilizing systems of boiler instalation, for optimization of method of different types. Industrial Heat Engineering, 36 (1), 41–46.
- Fialko, N., Stepanova, A., Presich, G., Navrodskaya, R., Sherenkovskiy, Yu. V., Maleckaya, O. E., Gnedash, G. A. (2012). Thermodynamic optimization and analysis of the efficiency of heat recovery system of boiler. Industrial heat engineering, 34 (2), 59–66. Available at: http://dspace.nbuv.gov.ua/bitstream/handle/123456789/59078/09-FialkoNEW.pdf?sequence=1
- Kuznetsov, N. V., Mitor, V. V., Dubovskiy, I. E. (2011). Heat calculation of boiler units. Kyiv: Publisher Ekolit, 296.
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2018 Nataliia Fialko, Alla Stepanova, Raisa Navrodska, Nataliia Meranova, Yulii Sherenkovskii
This work is licensed under a Creative Commons Attribution 4.0 International License.
The consolidation and conditions for the transfer of copyright (identification of authorship) is carried out in the License Agreement. In particular, the authors reserve the right to the authorship of their manuscript and transfer the first publication of this work to the journal under the terms of the Creative Commons CC BY license. At the same time, they have the right to conclude on their own additional agreements concerning the non-exclusive distribution of the work in the form in which it was published by this journal, but provided that the link to the first publication of the article in this journal is preserved.
A license agreement is a document in which the author warrants that he/she owns all copyright for the work (manuscript, article, etc.).
The authors, signing the License Agreement with TECHNOLOGY CENTER PC, have all rights to the further use of their work, provided that they link to our edition in which the work was published.
According to the terms of the License Agreement, the Publisher TECHNOLOGY CENTER PC does not take away your copyrights and receives permission from the authors to use and dissemination of the publication through the world's scientific resources (own electronic resources, scientometric databases, repositories, libraries, etc.).
In the absence of a signed License Agreement or in the absence of this agreement of identifiers allowing to identify the identity of the author, the editors have no right to work with the manuscript.
It is important to remember that there is another type of agreement between authors and publishers – when copyright is transferred from the authors to the publisher. In this case, the authors lose ownership of their work and may not use it in any way.
