NUMERICAL INVESTIGATION OF THE INFLUENCE OF VARIOUS PARAMETERS ON THE THERMOCHEMICAL PROCESSING OF THE COKE-ASH STRAW PARTICLE IN THE FIXED BED

Keywords: fixed bed, straw, combustion, reaction, heat exchange, concentration, carbon, oxygen

Abstract

Equations describing the rate of carbon conversion in the range of surface and bulk reactions are obtained taking into account the kinetics of heterogeneous reactions for the diffusion, kinetic and transition regions of the reaction. Deriving the equations, it was assumed that in the zone with a high carbon concentration (<<) reaction proceeds on the surface of the particle according to the model of a compressible combustible core, so that diameter of the particles decreases. In the second zone (≤) reaction proceeds in the volume with the same particle size. Here we use the model of a strong ash frame when the reaction proceeds throughout the volume of the particle. On the basis of the constructed equations, a model for thermochemical processing of the solid fuel coke-ash particle in a fixed bed is developed, taking into account the radiative and conductive-convective heat transfer between the bed and the particle and the heat release of chemical heterogeneous reactions. Numerical studies have been carried out in the intervals of surface and volumetric reacting in order to obtain detailed information on the geometric, aerodynamic, thermal, and physicochemical parameters of the combustion and gasification of a particle of straw in a fixed bed. It is shown that: a) with a decrease in the size of the coke-ash biomass particle, the time intervals for warming up and burning out are narrowed; b) expansion of the range of the volumetric reacting promotes an increase in the burnout time of the particle; d) As the concentration of oxygen in the gas mixture decreases, the rate of conversion of carbon and the temperature of the particle decrease, so that the time for the thermochemical treatment of the coke-ash straw particle increases.

Author Biographies

B. Rokhman, Coal Energy Technology Institute NAS of Ukraine

Information about the author: the leading researcher of the Institute of Coal Energy Technologies of the NAS of Ukraine, doctor of technical sciences. Biographical information of Rohman B.B. is published in well-known world directories «Who's Who in Science and Engineering» and «2000 Outstanding Intellectuals of the 21st Century».

Education: Novocherkassk Polytechnic Institute.

Research area: mathematical modeling of aerodynamics, heat and mass transfer and chemical reaction of a polydisperse ensemble of solid fuel in chamber and layer furnaces, in reactors with a circulating fluidized bed and in the fluidized bed.

Publications: more than 90 scientific papers, 27 of them are contained in the science-based Scopus database and 4 in the science-based Web of Science database.

S. Klyus, Institute of Renewable Energy, NAS of Ukraine

Information about the author: candidate of technical sciences, research fellow, Department of Renewable Organic Energy Carriers IRE NAS of Ukraine.

Education: Sumy State University, 2010.

Research area: bioenergy, biocoal, gasification.

Publications: 17, including 4 patents.

References

1. Rokhman B.B. (2015). Theoretical Investigation of the Process of Steam–Oxygen Gasification of Coke-Ash Particles in a Fluidized Bed Under Pressure Journal of Engineering Physics and Thermophysics. – Volume 88, Issue 2. – Pp. 313–328 (in Eng)
2. Shrayber A.A., Rokhman B.B., Kharchenko A.V. (1996). K matematicheskomu modelirovaniyu evolyutsii sos-toyaniya goryashchikh chastits v psevdoozhizhennom sloye [To mathematical modeling of the evolution of the state of burning particles in a fluidized bed] Prom. Teplotekhnika. – Volume 18, №1, – Pp. 86–91 (in Rus)
3. Rokhman B.B. (2012). Modelirovaniye protsessa vygo-raniya koksozol'nykh chastits v kipyashchem sloye [Modeling of the process of burning-out of coke–ash particles in a fluidized bed] Inzhenerno-fizicheskiy zhurnal – Volume 85, №3, – Pp. 526–534 (in Rus)
4. Baskakov A.P., Lukachevskiy B.P., Mukhlenov I.P. (1986). Raschety apparatov kipyashchego sloya. Spravoch-nik.[Calculations of fluidized bed apparatus. Reference book.] – Leningrad, USSR: Khimiya, – 351 p. (in Rus)
5. Pomerantsev V. V., Aref'yev K. I., Akhmedov D. B. (1986). Osnovy prakticheskoy teorii goreniya [Fundamentals of the practical theory of combustion]. – Leningrad, USSR: Ener-goatomizdat, – 312 p. (in Rus)

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Published
2018-09-11
How to Cite
Rokhman, B., & Klyus, S. (2018). NUMERICAL INVESTIGATION OF THE INFLUENCE OF VARIOUS PARAMETERS ON THE THERMOCHEMICAL PROCESSING OF THE COKE-ASH STRAW PARTICLE IN THE FIXED BED. Vidnovluvana Energetika, (3 (54), 67-76. Retrieved from https://ve.org.ua/index.php/journal/article/view/154