Obtaining kinetic characteristics of combustion of the coke from solid biofuels

Authors:

I.V.Beztsennyi, orcid.org/0000-0001-6536-5121, Coal Energy Technology Institute of the National Academy of Sciences of Ukraine, Kyiv, Ukraine, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

D.L.Bondzyk, orcid.org/0000-0003-3123-1971, Coal Energy Technology Institute of the National Academy of Sciences of Ukraine, Kyiv, Ukraine, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

T.S.Shchudlo, orcid.org/0000-0002-2754-2032, Coal Energy Technology Institute of the National Academy of Sciences of Ukraine, Kyiv, Ukraine, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

N.I.Dunayevska, orcid.org/0000-0003-3271-8204, Coal Energy Technology Institute of the National Academy of Sciences of Ukraine, Kyiv, Ukraine, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

повний текст / full article

Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu. 2020, (6): 015 - 020

https://doi.org/10.33271/nvngu/2020-6/015

Abstract:

Purpose. Obtaining the kinetic constants of the interaction of coke residues of different types of solid biomass with air oxygen to calculate the burn-out time of biofuel particles of different sizes in a wide range of temperatures.

Methodology. The initial data on carbon decrease over time at varying temperatures was obtained experimentally. The coke-ash residue was prepared in two stages, by placing and holding the initial biomass in an inert medium at temperatures of 750 and 900 C. The values of the activation energy and the chemical constant of the reaction rate were calculated by the method of least squares. The kinetic constants are calculated from the first-order reaction model in the Arrhenius approximation.

Findings. It is found that the dependence of the specific per initial mass burning rate of coke residues at constant temperature has a segment of constant rate within the conversion range from 0.15 to 0.8, at a particle temperature of 600 C, and decreases with increase in particle temperature. Based on the obtained kinetic constants, the temperature dependence was constructed of the specific burning rate of coke-ash residues of pine pellets, wheat straw and sunflower husks in the range of 6001600 C. It was found that under the same combustion conditions the burning rate of coke-ash residue of wheat straw pellets is the highest, and pine pellets is the lowest.

Originality. For the first time, the kinetic constants were obtained of the interaction of coke-ash residues of pine pellets, wheat straw and sunflower husks of Ukrainian origin with air oxygen in the conditions of fast heating.

Practical value. The proposed method for calculating specific rate of coke residues combustion with the obtained kinetic constants can be used to calculate the burning time for biofuel particles of different size in the furnaces of thermal installation in a wide range of temperatures, as well as to select the optimal biomass particles size for co-firing and separate combustion.

Keywords: kinetic constants, coke-ash residue, biomass

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