## THERMAL SCIENCE

International Scientific Journal

### Thermal Science - Online First

online first only
### Numerical modeling of peat burning processes in a vortex furnace with countercurrent swirl flows

**ABSTRACT**

The paper presents the process of peat burning in a swirl furnace with countercurrent swirl flows and the results of a numerical study. The cyclone-vortex technology of solid fuel combustion allows the furnace volume of a boiler unit, its dimensions and weight to be reduced. The aim of the work is a numerical study of the combustion of pulverized peat in a cylindrical vortex furnace with countercurrent swirl flows. The results of computer simulation of the combustion of pulverized peat with a moisture content of 40%, an ash content of 6% and a higher heat of combustion Qрн = 12.3 MJ/kg are presented. The results of the influence of the design parameters of the furnace and heat load (from 100% to 15%) are given as well. When the heat load is reduced to 15%, the entrainment of unburnt particles increases. The cooled and adiabatic furnace is studied. A significant entrainment of unburned particles is observed n a cooled furnace. The fields of temperature distribution, gas velocity and particle trajectory in the volume and at the outlet of the furnace are determined. The three-dimensional temperature distribution in the furnace volume indicates the combustion of peat particles at temperatures (1300-1450°C). Values of the tangential velocity of a swirl flow near the furnace outlet reach 150 - 370 m/s, which ensures the efficiency of separation of fuel particles and a reduction in heat loss due to mechanical underburning (up to 0.06%). The results of a numerical study show that the diameter of peat particles affects the combustion process, namely coke of particles with an initial diameter from 25 microns to 250 microns burns out by 96%, and particles with a diameter of about 1000 microns are carried away from the furnace and do not burn. The furnace provides a complete combustion of dust particles of peat by 99.8% and volatiles by 100%.

**KEYWORDS**

PAPER SUBMITTED: 2019-03-05

PAPER REVISED: 2020-03-16

PAPER ACCEPTED: 2020-04-07

PUBLISHED ONLINE: 2020-05-02

- Basu, P., Biomass Gasification and Pyrolysis. Practical Design and Theory, Elsevier, 2010.
- Serant, F.A., Shestakov S.M., Pomerancev V.V. et al. Burning Asian Old Brown Coals in a Low-Temperature Vortex Furnace according to the Scheme LPI-ITES-10, Thermal Engineering, 1983, (In Russian).
- Rundygin, Yu. A., et al., Modernization of Boilers based on Low-Temperature Vortex Technology for Burning Solid Fuels, Energy: economics, technology, ecology, 4 (2000), pp. 19-22.
- Shestakov, S. M., Aronov, A. L., Technology of Combustion of Local Solid Fuel Types, ESCO, 2014.
- Baskakov, A.P., et al., Boilers and Furnaces with a Fluidized Bed, Energoatomizdat, Moscow, Russia, 1996.
- Shtym, A.N., Shtym, K.A., Kotelnye ustanovki s tsyclonnymi predtopkami
- Dolejal, R.N., Furnaces with Liquid Slag Removal, GosEnergoizdat, 1959. (In Russian).
- Khzmalyan, D.M., Theory of Furnace Processes, Energoizdat, 1990. (In Russian).
- Knorre, G.F., Nadzharov, M.A., Cyclone Furnaces, GosEnergoizdat, 1959. (In Russian).
- Marshak, Yu.L., Furnaces with Vertical Cyclone Prefurnaces, Energy, 1966. (In Russian).
- Safarik, P., Askarova A., Bolegenova, S., 3D Modelling of Heat and Mass Transfer during Combustion of Low -Grade Coal, 2020 doi.org/10.2298/TSCI191107062S
- Safarik, P., Maximov, V.Yu., Bolegenova, S.A., et al., 3D Modeling the Activated Combustion Thermochemical Fuel, News of the national academy of sciences of the Republic of Kazakhstan-series physico-mathematical, 2 (2019), 324, pp. 9-16.
- Anikin, Yu.A., et al. Vortex Steam Generator of a New Type Modeling of Furnace Processes., Proceedings of VIII All-Russian Conference with the International Part "Combustion of Solid Fuel" Institute of Thermophysics named after S.S. Kutateladze SORAN, 2012, pp. 51-66.
- Glushkov, D.O., et al., Numerical research of heat and mass transfer during low-temperature ignition of a coal particle, Thermal Science, 19 (2015), pp. 285-294.
- Chen, X., Zhang, Y., Zhang, Q., et al., Thermal Analyses of the Lignite Combustion in Oxygen-Enriched Atmosphere, Thermal Science, 2015, Vol. 19, No3, pp. 801-811
- Lomovsky, O., Bychkov, A., Lomovsky T., Mechanochemical production of lignin-containing powder fuels from biotechnical industry waste: A REVIEW et. al.TS: 2015, vol. 19 No1, pp. 21a - 22a
- Redko, A., Redko, O, DiPippo, R., Low-Temperature Energy Systems with Applications of Renewable Energy, Elsevier Academic Press, 2019.
- Sazhyn, B.S., Gudim, L.I., Vortex Dust Collectors, Chemistry, 1995. (In Russian).
- LaRose, J.A., Hopkins, M.W., Numerical Flow Modeling of Power Plant Windboxes, Power-Gen Americas 95, December 5-7, Anaheim, California, USA, 1995
- Bhasker, C., Simulation of air flow in the typical windbox segments, Adv. Eng. Software, 33 (2002), pp. 793-804
- Filkoski Risto, Petrovski Ilija, Karas Piotr, Optimisation of pulverised coal combustion by means of CFD/CTA modelling, Thermal Science, Vol. 10, No. 3, 2006. Pp. 161-179
- James, T. Hart, Md. Rezwanul Karim, Arafat, A. Bhuiyan, Peter Witt, Jamal Naser, Numerical modelling of unsteady flow behavior in the rectangular jets with oblique opening, Alexandria Engineering Journal, 55 (2016), pp. 2309-2320
- Crow, D., Numerical Models of Gas Flows with a Small Content of Particles, Foundations of Engineering Calculations, 1982. (In Russian).
- Launder, B. E., Spalding. D. B., Lectures in Mathematical Models of Turbulence, London : Academic Press, 1972. 169 p.
- Jones, W.P., Calculation Methods for Reacting Turbulent Flows: A Review, Combust. Flame. Whitelaw, 1982.
- Loitsyanskii, L.G., Mechanics of Fluid and Gas. Nauka, 1978. (In Russian).
- Badzioch, S., Hawksley, P. G. W., Kinetics of Thermal Decomposition of Pulverized Coal Particles, Ind. Eng. Chem. Process Design and Development, 1970.
- Vandoormaal, J. P., Raithby, G. D., Enhancements of the SIMPLE Method for Predicting Incompressible Fluid Flows, Numer. Heat Transfer, 1984.
- Surzhikov, S.T., Thermal Radiation of Gases and Plasma, Moscow, 2004. 544 p. (In Russian).
- Philip, J., Stopford Recent application of CFD modelling in the power generation and combustion industries, Applied Mathematical Modelling, 26 (2002), pp. 351-374
- Audai Hussein Al-Abbas, Jamal Naser Computational fluid dynamic modelling of a 550 MW tangentially - fired furnance under different operation conditions, Procedia Engineering, 56 (2013), pp. 387-392
- Tai Lv, Qian Wang, Jie Leng, Numerical and Experiment Research for Soft Coal under Condition of Blending Lignite, Energy Procedia, 17 (2012), pp. 1001 - 1006
- Buthalura, R., Vuthalura, H.B., Modelling, of a wall-fired furnace for different operating conditions using FLUENT, Fuel Process. Technol., 87 (2006), pp. 633-639
- Chui E.H., Raithby G.D., Computation of Radiant Heat Transfer on a Noh - Orthogonal Mesh Using the Finite - Volume Method, Numerical Heat Transfer. Part B. 1993. - N3. - pp. 269-288.
- Bass, L.P., Voloshchenko, A.M., Germogenova T.A., Methods of Discrete Ordinate in Radiation Transfer Problems, Moscow, Institute of Applied Mathematics, USSR Academy of Sciences, 1986.
- Engineering Simulation & 3-D Desing Software
- Poinsot, T., Veynante D., Theoretical and numerical combustion/ - 2nd ed. R.T. Edwards. Inc., 2005. 522 pp.