Use of Fabaceae and pine sawdust as alternatives to pelletizing for energy purposes

The growing global demand for renewable energy has driven the development of the wood pellet sector. This growth is part of the global energy transition, which is aimed at replacing fossil fuels with sustainable alternatives. This transformation responds to the challenges of global warming and the urgent need to reduce carbon emissions. In this regard, in the present work, sawdust from four species of Fabaceae ( Acacia farnesiana , A. pennatula , Albizia plurijuga , and Prosopis leavigata ) was used to make pellets, and pine sawdust was used for comparison. The following characteristics were analyzed: granulometry, proximate analysis, higher calorific value, elemental analysis, ash microanalysis, particle density, bulk density, and mechanical durability. These results indicate that the granulometry of all the sawdust samples is suitable for pelletizing. Pine pellets contain a lower concentration of ash than Fabaceae pellets do, but all are classified as nonindustrial use. Owing to the amount of inorganic matter, pine and Fabaceae pellets are classified into the following classes: A1 ( Pinus spp.), 2 A ( A. plurijuga ), and B ( A. farnesiana , and P. leavigata ). The Fabaceae pellets presented a greater fixed carbon content than did the pine pellets. The calorific value of all pellets exceeded the limit established by the standard. The elemental composition was within the parameters of other wood species. Twenty-two chemical elements were identified in the pellet ash, with the most common elements being Ca and K. Due to the mechanical durability results, Fabaceae pellets could have local uses.