The thermal decomposition of wood chips from an apple tree is studied in a static air atmosphere under isothermal conditions. Based on the thermogravimetric analysis, the values of the apparent activation energy and pre-exponential factor are 34 ± 3 kJ mol⁻¹ and 391 ± 2 min⁻¹, respectively. These results have also shown that this process can be described by the rate of the first-order chemical reaction. This reaction model is valid only for a temperature range of 250–290 °C, mainly due to the lignin decomposition. The obtained results are used for kinetic prediction, which is compared with the measurement. The results show that the reaction is slower at higher values of degree of conversion, which is caused by the influence of the experimental condition. Nevertheless, the obtained kinetic parameters could be used for the optimization of the combustion process of wood chips in small-scale biomass boilers.

Nowadays the biomass or more precisely biofuel is more and more being exploited as a substitute for fossil fuels for heating as well as for example for heating of drying surroundings. The contribution is focused on reviewing of heat source by the combustion of various kinds of solid biofuels. It is a boiler VIGAS 25 with regulation AK 2,000 for heating the house and boilers VESKO-B and RH 4000. For the measurement of gaseous emissions was used device TESTO 330-2LL and other facilities. Firewood, peat briquettes, briquettes from the bark and hardwood briquettes were burned. Results of experimental measurements of production of gaseous emissions are processed in the tables and graphs depending on the performance of the boiler and the combustion time. Quantity of production of gaseous emissions depends mainly on the amount and uniformity of the fuel, the relative humidity of fuel, type of fuel and keeping the fuel mix prescribed by the manufacturer of the boiler. Found concentrations of gaseous emissions showing compliance with the statutory emission limits.

Bioenergy is considered the largest contributor to the renewable and sustainable energy sector worldwide, playing a significant role in various energy sectors such as heating, electricity supply, and even in replacing fossil fuels in the transportation sector. As part of renewable, low-carbon energy systems, bioenergy can also ensure atmospheric carbon sequestration, provide numerous environmental and socio-economic benefits, and thus contribute to achieving global climate change goals, as well as broader environmental, social, economic, and sustainable development objectives. The use of bioenergy can significantly reduce our carbon footprint and thus contribute to improving the environment. While bioenergy conversion of biomass produces some amount of carbon dioxide, similar to traditional fossil fuels, its impact can be minimized by replacing forest biomass with fast-growing trees and energy crops. Therefore, fast-growing trees and energy crops are the primary raw materials for bioenergy. The results of the research in this publication confirm the high efficiency of biomass depolymerization through thermochemical conversion. The principle of continuous biomass conversion was used at a process temperature of 520 °C. The experiments were carried out in the Biomass Gasification Laboratory at the AgroBioTech Research Center of the Slovak University of Agriculture in Nitra. The biomass used for the experiments was from energy-producing fast-growing willows, specifically the varieties Sven, Inger, and Express. The aim was to determine the amount of biochar produced from each of these tree species and subsequently to investigate its potential use for energy purposes. During the experiments, 0.106 kg of biochar was produced from 1 kg of Inger willow biomass, 0.252 kg from 1 kg of Express willow biomass, and 0.256 kg from 1 kg of Sven willow biomass. A subsequent goal was to determine the production of gas, which can also be used for energy purposes. The biofuel samples obtained were subsequently subjected to thermogravimetric analysis to determine moisture content, volatile matter, and ash content. The ash content in dry matter ranged from 6% to 7.28%, while the volatile matter in dry matter was between 92.72% and 94%. The moisture content in the samples ranged from 1.7% to 2.43%. These results may contribute to innovative insights into biomass depolymerization and help define optimized parameters for thermochemical conversion, as well as the required biomass composition, with the goal of generating second-generation biofuels in the most cost-effective way.

Maize is harvested after reaching maturity when its moisture content generally ranges from 30 % to 34 %, while the optimum moisture for storage is around 14-15 %. This moisture is usually achieved by thermal drying. Apart from initial moisture, the total drying time is affected by the temperature of the drying environment, atmospheric conditions and properties of the dried material. The present paper provides a description of the process of moisture loss and subsequent drying rate of grain maize from various growers. Obtained results are processed in a tabular and graphical form. After 30 minutes of drying, all the maize samples (10 samples two times in total) reached a moisture of 14 % and less, whereas 6 samples already after 20 minutes of drying. The rate of moisture loss was proportional to the initial moisture content. The drying of grain maize is considered one stage of the technological procedure in post-harvest treatment. Moreover, it is an essential preventive measure for wet harvest. Contemporary technologies of maize drying in modern dryers favourably influence the energy consumption in the process while maintaining the qualitative parameters of the dried material.

The results of the experimental measurements based on the engine-speed map of the gasoline, LPG and hybrid drive engines are presented. When using LPG, there are no differences in torque and power at lower revolutions. However, the differences are essential for hybrid drive in its favour. This is convenient in urban traffic. Equally calculated engine flexibility values are higher for the hybrid drive. The use of LPG fuel or hybrid drive also contributes to lower production of emissions.

Biomass provides a great diversity of input materials and universal use, not only for heat generation but also electricity generation in modern incinerators. For the most eficient use of solid biofuels, it is necessary to know their physico-chemical properties. The work focuses on the gravimetric analysis of selected types of biofuels. This paper presents the results of measurements for moisture content, ash and combustibles in selected solid biofuels. Experiments represent a follow-up to measurements performed to date.