Vol. 337 No. 5 (2026)
DOI https://doi.org/10.18799/24131830/2026/5/5139
Porous particle effective thermal conductivity under torrefaction conditions
Relevance. Currently, the technology of low-temperature pyrolysis of biomass, including waste from woodworking and logging (wood pellets), is being developed. In this relation the mathematical models of the carbon-containing particles torrefaction in a gas stream are being developed and investigated. One of the tasks that arise in mathematical modeling is the choice of a method for calculating the thermal conductivity of porous wood pellets subjected to thermochemical processing in a gas stream at temperatures from 300 to 1000 K. A significant number of studies are devoted to the investigation and development of methods for calculating heat transfer in porous bodies. Many models of thermal conductivity of porous bodies have been proposed, based on five main models: parallel model, sequential model, two variants of the Maxwell–Aiken model, and efficient medium model. The following formulas are used in the Russian scientific community: G.N. Dulnev, N.Y. Taits, L.A. Brovkin, V.I. Odelevsky. Aim. To perform a comparative analysis of formulas for calculating the coefficient of effective thermal conductivity of porous bodies under conditions of wood pellets torrefaction, taking into account the effect of radiative heat transfer in the pores, to develop the recommendations on the choice of formulas. Object. Torrefied wood pellets. Methods. Mathematical modeling, comparative analysis. Results and conclusions. The basis for choosing the formula for calculating the effective thermal conductivity coefficient should be experimental data on the porosity of bodies and pore sizes, as well as on the thermal conductivity of porous bodies in the temperature range corresponding to the process under study. In the absence of such data, it is recommended to use the equation corresponding to the parallel model of a porous body, adjusted for radiative heat transfer according to L.A. Brovkin method.
Popov S.K., Valineeva A.A., Borissova N.G. Porous particle effective thermal conductivity under torrefaction conditions. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering, 2026, vol. 337, no. 5, pp. 63-73. https://doi.org/10.18799/24131830/2026/5/5139
Keywords:
Wood pellets, torrefaction, low-temperature pyrolysis, effective thermal conductivity, porous materials
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