Valorization of argan fruit residues to produce thermal energy by combustion

Abstract

This study investigates the valorization of argan fruit residues into compressed biofuel logs as a sustainable energy solution for Morocco. With annual argan oil production exceeding 4000 tonnes and generating over 80,000 tonnes of waste, we developed an optimized process involving solar drying (reducing moisture to ≤10 % in 3 days, 50 % faster than open-air drying), grinding, and mixing with 20 % beeswax before hydraulic pressing. Experimental combustion tests revealed that the argan logs achieved a peak temperature of 460 °C within 45 min significantly outperforming wood (400 °C) and olive pomace (420 °C). The combustion process exhibited three distinct phases: rapid temperature increase (0–45 min), stable high-temperature maintenance (45–150 min at 460 ± 2 °C), and gradual cooling (150–420 min). Notably, the logs demonstrated a 250-minute sustained burn duration, 39 % longer than conventional wood fuels, attributed to the beeswax's calorific contribution (628 kcal/kg). These results demonstrate that argan waste logs offer superior thermal performance while addressing environmental concerns through waste valorization. The study provides a complete circular economy model from agricultural byproduct to value-added bioenergy source, with particular relevance for Mediterranean regions seeking sustainable alternatives to fossil fuels and traditional biofuels.