Production of fuel pellets from bean crop residues (Phaseolus vulgaris)

Beans are an important part of the Mexican diet, and its cultivation generates a significant amount of waste. This biomass contains important amounts of carbon, which makes it a potential source to obtaining fuel pellets. Therefore, this work proposes the production of fuel pellets from bean residues considering as control factors the particle size and moisture content. The fuel pellets of best quality were obtained from biomass with a moisture content of 20% and a particle size of 8.00 mm before its densification (M3P2 samples); these fuel pellets reached a higher heating value of 16.097 MJ/kg, 5.319% of dry weight ashes, a bulk density of 607.38 kg/m3, a final moisture of 11.679%, an individual density of 1.1979 g/cm3, a final diameter of 8.13 mm, a final length of 18.50 mm, a final carbon content of 54.322%, and a yield of 60.7%. Based on these results, the fuel pellets produced from the residues of the bean crop satisfy the ISO 17225–6 standard, and they can replace solid fossil fuels for generation of electrical and/or thermal energy.