Wood modification with the improvement of its physical and mechanical properties is a promising way to increase the commercial quality of the material and enhance its sustainable use. This article presents the results on developing a model for impregnation with water of fine coniferous and non-coniferous wood by centrifugal processing techniques. The mathematical modeling is based on Darcy’s law. According to the model representation, the impregnation rate of the wood assortment is proportional to the pressure ratio of the treating solution. The proportionality factor is a constant value that depends on the breed of wood. Performed comparative analysis revealed the perfect consistency of calculations made using the formula of a centrifugal model with the experimental data. According to the analysis of impregnation rate time dependencies, the main saturation of the treated sample with liquid (70%) occurs in 1/3 of the complete cycle time. Besides, the established model allows determining with high accuracy the impregnation time as a function of atmospheric pressure, rotational speed, and the ratio of assortment wood length to centrifuge platform radius for different wood breeds. Further studies are planned on evaluating the effect of different liquids viscosity on the kinetics of wood impregnation as well as determining the applicability of the proposed model.

In the coming decades, wood waste management for biofuel production is regarded as a promising renewable energy source and a key factor in reducing carbon dioxide emissions. Mechanical grinding is seen as one of the main techniques in wood waste pre-treatment operations that increases the value of feedstock used for fuel. The application potential of the ground product highly depends on the energy effi ciency of the process.This work aimed to establish a consistent pattern for estimating the energy consumption required for grinding spruce and pine barking waste depending on the degree to which materials are ground and their relative moisture content. The energy consumption parameters at grinding were analyzed employing three grinding energy models of Rittinger, Kripichev-Kik, and Bond. The results of estimation showed that specifi c energy consumption is associated with relative moisture content and the grinding degree by nonlinear dependence according to the Kripichev-Kik grinding model for spruce and pine bark. It has been established that the specifi c energy consumptionat grinding spruce and pine barking waste at the optimum humidity of 25% and 27%, respectively, is proportional to the natural logarithm of the grinding degree. It was concluded that the wood waste grinding by 5-15 times requires higher energy consumption at optimum moisture content, which is 5-10% and 7-14% of the heating value for spruce and pine, respectively. The knowledge acquired through this research will contribute to developing possible approaches for wood waste recycling in a more energy-effi cient way.

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