Release:
2022. Vol. 8. № 3 (31)About the authors:
Andrey V. Gil, Cand. Sci. (Tech), Associate Professor, Butakov Research Center, National Research Tomsk Polytechnic University; andgil@tpu.ruAbstract:
The article presents the study of combustion and heat transfer processes in large-scale objects are extremely difficult both analytically and experimentally. The combustion of non-design coals in boiler units is often accompanied by a decrease in the completeness of fuel burnup, undesirable redistribution of heat flows and other negative factors due to different thermal characteristics of the fuel. The possibility of effective burnout of polyfractional non-design solid fuel in the combustion chamber of a boiler unit with solid ash removal is considered on the basis of a numerical study of jointly occurring aerothermochemical processes. The problem of numerical modeling of the staged burnout of coal particles is solved, starting from the evaporation of the moisture contained in them to the burning out of their coke residue when moving in the carrier phase. Numerical studies of physical and chemical processes in the combustion chamber were carried out for three loads (50%, 70%, 100%) based on the developed FIRE 3D calculation complex. The Euler-Lagrange model for a dusty flow is applied, the closure of the averaged Navier-Stokes equations is performed by the k-ε turbulence model, the second order of accuracy is used in numerical calculations. The main results of three-dimensional modeling are presented in the form of velocity and temperature fields, the distribution of O2 and CO concentrations along the height of the furnace volume. The results of mathematical modeling showed good agreement with the available analytical values. Based on the data obtained, it can be stated that it is possible to organize the combustion of non-design fuel in the boiler unit under consideration. It has been established that when operating at loads below the nominal, a redistribution of burner jets is observed, which negatively affects the reliability and efficiency of the boiler. To increase the efficiency of the boiler unit at reduced loads, a wider study of options for redistributing the proportions of the fuel-air mixture and secondary air is necessary.References:
1. Bautin S. P., Obukhov A. G. 2019. “Numerical simulation of complex gas flows in concentrated fire vortices”. Physical and Mathematical Modeling. Oil, Gas, Energy, vol. 5, no. 3, pp. 47-68. [In Russian]
2. Bubenchikov A. M., Starchenko A. V. 1998. Numerical models of dynamics and combustion of aerodisperse mixtures in channels. Tomsk: TGU. [In Russian]
3. Volkov E. P., Prokhorov V. B., Chernov S. L., Kirichkov V. S., Kaverin A. A. 2020. “Investigation of the combustion process of solid fuel in furnaces with direct-flow burners”. Thermal Engineering, vol. 67, pp. 365-373. [In Russian]
4. Gil A. V., Starchenko A. V. 2012. “Mathematical modelling of physical and chemical processes of coal combustion in chamber furnaces of boiler aggregates based on the package of applied programs FIRE 3D”. Thermophys Aeromechanics, vol. 19,
pp. 503-519. [In Russian]
5. Graham Y. The global electricity review. 2021. https://ember-climate.org/wp-content/uploads/2021/03/Global-Electricity-Review-2021-Russia-Translate.... [In Russian]
6. Marshak Yu. L., Verzakov V. N. 1982. “Investigation of the combustion of Berezovsky coal in a tangential furnace transmission with gas fuel drying”. Thermal Power Engineering, no. 8, pp. 4-9. [In Russian]
7. Patankar S. 1980. Numerical heat transfer and fluid flow. Hemisphere Publishing Corporation. New York. [In Russian]
8. Starchenko A. V., Zavorin A. S., Krasilnikov S. V. 2002. “Application of the FIRE 3D package to the analysis of slagging processes”. Bulletin of the Tomsk Polytechnic University, vol. 305, no. 2. pp. 152-157. [In Russian]
9. Starchenko A. V., Zavorin A. S., Krasilnikov S. V. 2004. “Numerical evaluation of slag capture in an open furnace with liquid ash removal”. Bulletin of the Tomsk Polytechnic University, vol. 307, no. 2. pp. 127-133. [In Russian]
10. Supranov V. M., Izyumov M. A., Roslyakov P. V. 2011. “Studying the possibility of running the TPE208 boiler of unit 1 at the Smolensk district power station on off-design coals”. Thermal Engineering, vol. 58, no. 1, pp. 46-57. [In Russian]
11. Taylasheva T. S., Gil A. V., Vorontsova E. S. 2016. “Evaluation of burning conditions of high humidity non project fuel in chamber furnace based on numerical simulation”. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, vol. 327, no. 1, pp. 128-135. [In Russian]
12. Kagan G. M. 1998. Thermal calculation of boilers (normative method). 3rd ed., revised and additional. Saint-Petersburg: VTI. [In Russian]
13. Audai Hussein Al-Abbasa, Jamal Naser, Emad Kamil Hussein. 2013. “Numerical simulation of brown coal combustion in a 550 MW tangentially-fired furnace under different operating conditions”. Fuel, vol. 107, pp. 688-698.
14. Bartłomiej Hernik, Grzegorz Latacz, Dominik Znamirowski. 2016. “A numerical study on the combustion process for various configurations of burners in the novel ultra-supercritical BP-680 boiler furnace chamber”. Fuel Processing Technology, vol. 152,
pp. 381-389.
15. Baum M. M, Street P. J. 1971. “Predicting the combustion behaviour of coal particles”. Combust Sci Technol, vol. 3, pp. 231-243.
16. Cuiliu Zhang, Guangwei Wang, Xiaojun Ning, Jianliang Zhang, Chuan Wang. 2020. “Numerical simulation of combustion behaviors of hydrochar derived from low-rank coal in the raceway of blast furnace”. Fuel, vol. 278, art. 118267. 8 p.
17. Gil A. V., Zavorin A. S., Starchenko A. V. 2019. “Numerical investigation of the combustion process for design and non-design coal in T-shaped boilers with swirl burners”. Energy, vol. 186, art. 115844. 14 p.
18. Hatami Mohammad, Heydari Abbas. 2022. “Thermal optimization for the tangential swirl burner at the rotary furnace of steel pipe industry to save energy and reduce emissions”. Alexandria Engineering Journal, vol. 61, no. 9, pp. 6675-6694.
19. Karampinis E., Nikolopoulos N., Nikolopoulos A., Grammelis P., Kakaras E. 2012. “Numerical investigation Greek lignite/cardoon co-firing in a tangentially fired furnace”. Applied Energy, vol. 97, pp. 514-524.
20. Magnusen B. F., Hjertager B. H. 1976. “On mathematical modeling of turbulent combustion with special emphasis on soot formation and combustion”. Proceedings of 16th Int. Symposium on Combustion, pp. 719-727.
