Abstract
An approximate physical model of coal heat pretreatment with external heat input in a cyclone-type unit is presented and its governing principles are examined. The model makes it possible to predict the time of moisture release from the fuel (or evaporation), the temperature of gas suspension and of fuel combustion, and the composition and volume of the combustion products. This enables one to determine the design and layout of the furnace extension for various process conditions. The model is based on the following assumptions: the processes are quasi-stationary, the heat capacities and heat transfer coefficients are constant and determined at an average process temperature, coal particles are isothermal, the gas suspension is uniform, ash components are inert, and the flow is one-dimensional. In addition, the model includes only the reactions governing the combustion processes. By an example of Kansk-Achinsk coal’s heat treatment, it has been established that the yield of combustible volatiles can be 30–40% (by mass) at a gasification degree of 0.35–0.60. The time of solid phase ignition is approximately 0.8 s from the onset of the process. In all cases, the products of heat treatment of coals at different phases of metamorphism contain at least 25% of combustible volatiles, thereby securing ignition of the solid phase. Basic design features of a small-size furnace extension acting as a boiler burner for steam-turbine power units are determined.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
REFERENCES
V. I. Babii, P. I. Alaverdov, V. M. Barbarash, and T. V. Kanaeva, “The effect of preheating coal dust on the output of "fuel” nitrogen oxides,” Teploenergetika, No. 9, 10–13 (1983).
V. I. Babii, E. Kh. Verbovetskii, and Yu. P. Artem’ev, “A burner with preliminary heat treatment of coal dust for reducing the formation of nitrogen oxides,” Therm. Eng. 47, 891–898 (2000).
M. S. Pronin, M. Ya. Protsailo, V. M. Ivannikov, B. V. Tsedrov, L. M. Kostina, G. E. Kosinskii, and V. V. Gordeev, “Development and experimental verification of the new technology and equipment for environmentally friendly thermal power plants on Kansk-Achinsk coal,” Teploenergetika, No. 2, 13–16 (1995).
Yu. A. Rundygin, “Ignition stability of high-moisture fuel in low-temperature vortex furnaces,” Izv. Vyssh. Uchebn. Zaved. Energ., No. 10, 74–81 (1983).
R. A. Kalinenko, A. A. Levitskii, Yu. A. Mirokhin, and L. S. Polak, “Mathematical model of pyrolysis and gasification of coal,” Kinet. Katal. 28, 723–729 (1978).
T. V. Vilenskii, “Calculation of comvustion processes in jet systems and combustion chambers,” Izv. Vyssh. Uchebn. Zaved. Energ., No. 10, 81–86 (1983).
Yu. Ya. Pechenegov, Modeling and Calculation of Heat Transfer of One and Two-Phase Systems in Tubeular Apparatus, Doctoral Dissertation in Engineering (Saratov, 1988).
P. A. Shchinnikov, “A solid fuel combustion method,” RF Patent No. 2120083, Byull. Izobret. No. 28 (1998).
M. Kh. Ibragimov, E. M. Marchenko, B. G. Tuval’baev, A. A. Dranchenko, N. B. Trubitsyn, and Yu. G. Naumov, “Experimental study of the model of the device for thermal preparation of fuel in coal-fired thermal power plants,” Izv. Vyssh. Uchebn. Zaved. Energ., No. 6, 62–65 (1987).
D. B. Spalding, Some Fundamentals of Combustion (Butterworth, London, 1955; Gosenergoizdat, Moscow, 1959).
N. V. Lavrov, Physico-Chemical Fundamentals of Fuel Combustion Process (Nauka, Moscow, 1971) [in Russian].
E. I. Karpenko, Plasma-Energy-Generation Technologies for the Integrated Use of Solid Fuels, Doctoral Dissertation in Engineering (Novosibirsk, 1995).
E. M. Suuburd, W. A. Peters, and J. B. Howard, “Product composition and kinetics of lignite pyrolysis,” Ind. Eng. Chem. Process Des. Dev. 17, 37–46 (1987).
P. R. Solomon, D. C. Hamblen, and R. M. Carangelo, “Coal thermal decomposition in an entrained now reactor experiments and theory,” in Proc. 19th Int. Symp. on Combustion, Haifa, Israel, Aug. 8–13, 1982 (Pittsburgh, PA, 1982), pp. 1139–1149.
M. Kozubova, Ya. Krutil’, and V. Nevrlii, “Experiments and mathematical models of methane flames and explosions in a complex geometry,” Combust., Explos., Shock Waves 50, 374–380 (2014).
A. C. Zambon and H. K. Chelliah, “Self-sustained acoustic-wave interactions with counter flow flames,” J. Fluid Mech. 560, 249–278 (2006).
Lu. Xijia and Ting Wang, “Water–gas shift modeling in coal gasification in an entrained-flow gasifier — Part 2: Gasification application,” Fuel 108, 620–628 (2013).
V. E. Messerle and A. B. Ustimenko, “Simulation of the organic-waste processing in plasma with allowance for kinetics of thermochemical transformations,” Thermophys. Aeromech. 24, 605–614 (2017).
M. Gorokhovski, E. L. Karpenko, F. C. Lockwood, V. E. Messerle, and B. G. Trusov, “Plasma technologies for solid fuels: Experimental and theory,” J. Energy Inst. 78, 157–171 (2005).
Author information
Authors and Affiliations
Corresponding author
Additional information
Translated by T. Krasnoshchekova
Rights and permissions
About this article
Cite this article
Shchinnikov, P.A., Frantseva, A.A. & Dvortsevoy, A.I. An Approximate Model of Heat Treatment and Ignition of Coal in Small Cyclones. Therm. Eng. 66, 505–512 (2019). https://doi.org/10.1134/S0040601519070073
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S0040601519070073