Assessment of the thermal characteristics of pellets made of agricultural crop residues mixed with wood

The use of agricultural biomass to produce biofuels and energy can provide many environmental and socio-economic benefits. This research project examines the possibility of replacing part of the wood material in a pellet with various proportions of residues of agricultural crops such as medic, maize, wheat bran, wheat straw, sunflower, and cardoon. Such substitution would contribute to the recycling of materials and the sustainable use of wood and other natural resources. It would reduce emissions of gaseous pollutants by replacing the use of other fossil fuels with solid biofuels. The chosen agricultural species, as well as the beech wood used in this work, are among the most widely-available raw materials in Greece and Europe. Specifically, the higher heating value (HHV) of these materials, both separately and mixed, and their respective ash contents (%), a feature highly crucial for their future utilization as biofuels, were estimated and compared among species. Additionally, various mixing ratios of these materials were examined to determine the most appropriate pellet-type biofuels that meet the requirements of the corresponding international standards that pose restrictions on thermal efficiency and ash content.