Thermochemical and elemental characterization of aromatic seed residues for solid biofuel applications in a circular economy context

Abstract: This study investigates the energy valorization potential of 16 aromatic seed residues (ASW), a by-product generated after essential oil extraction from Mediterranean aromatic and medicinal plants. Driven by the increasing demand for natural bioactive ingredients and the expansion of aromatic crop production, large amounts of residual biomass remain underutilized. Their incorporation into thermochemical conversion routes aligns with circular economy strategies, offering opportunities for renewable energy generation, waste minimization, and the development of value-added bioenergy products. The objective of this work is to provide a comprehensive thermochemical, elemental, and structural assessment of ASW to determine their suitability for solid biofuel production (pellets, briquettes), pyrolysis for bio-oil generation, and biochar applications. The samples were analyzed under standardized ISO methodologies to ensure comparability and adherence to industrial fuel quality requirements.