Development and Valorization of Bioenergy Briquettes Using Agro-Industrial Residues from a Semi-Arid Region

The valorization of agro-industrial residues for solid biofuel production represents a sustainable strategy to meet energy demand, reduce open-field burning, and mitigate environmental impacts. This study aimed to assess the feasibility of producing high-quality briquettes from agro-industrial residues such as oregano stems, pecan shells, and peanut shells sourced from a semi-arid region of northern Mexico. Raw materials were obtained from local industries, processed, and characterized through proximate analysis and determination of higher heating value (HHV). Briquettes were manufactured under various compaction pressures and temperatures without the use of binders, and their physical and energy properties were evaluated according to international standards. Results indicated that all briquette types met Class A quality standards, with moisture contents between 6 and 9%, ash contents below 6%, and HHVs ranging from 18.9 to 21.0 MJ kg−1. Pecan shell briquettes exhibited the highest particle density (1.18 g cm−3), while peanut shell briquettes demonstrated superior mechanical performance and the highest Impact Resistance Index (97% and 200, respectively). Oregano stem briquettes showed lower densities but maintained satisfactory energy properties (19.5 MJ kg−1). Beyond its energy potential, this valorization approach contributes to local economic development, reduces environmental pollution, and decreases dependence on firewood in rural communities.