Results of Laboratory Studies on the Process of Making Fuel Briquettes From Rapeseed Straw

Abstract

When producing fuel briquettes, the main material used for pressing is agricultural waste, specifically plant residues, which most often consist of straw from cereal and small-seeded crops. Therefore, the success of the briquetting process largely depends on the properties of their physico-mechanical component. Within the variation of the studied factors, as the average length of rapeseed straw particles decreases, the density and energy density of the briquettes increase. Also positively affecting these indicators are the increase in the content of binding material (clay or manure), the cone angle of the matrix, and the ratio of the cross-sectional area of the matrix channel to its perimeter. Increasing the moisture content of the pressed material leads to an increase in the density of briquettes and a decrease in their energy density. To ensure the production of briquettes with a density of over 600 kg/m², both with and without binding material, a round matrix should be used. The optimal temperature for heating the matrix during pressing is 160-180°C. This results in the release of lignin from rapeseed straw, which also acts as a binding agent. Furthermore, it enhances plasticization, accelerating relaxation processes, reducing friction coefficients, lowering the energy intensity of the process, and enabling the achievement of the required briquette quality. Pressing at a heating temperature of 160-180°C leads to stable production of rapeseed straw briquettes with a moisture content of the initial material of up to 16%. In the case of particle size reduction to 20 mm, briquetting can be performed without adding a binding agent. The most acceptable initial moisture content of the briquetting mass is 8-12%. Higher moisture results in fluffy briquettes, while lower moisture leads to less density. With moisture exceeding 16%, intensive steam formation occurs in the pressing chamber, which is dangerous during operation.