Pilot-scale production of biochar from eucalyptus wood chips for carbon sequestration

Abstract Biochar is recognized as a negative emission technology with agronomic and environmental benefits, yet studies addressing its production under industrial conditions remain scarce. This study aimed to evaluate the yield, physicochemical stability, and environmental safety of biochar produced from eucalyptus wood chips in a pilot-scale continuous horizontal reactor operating at 430 °C, and to estimate its carbon sequestration potential. The process produced 28% biochar (w/w) containing 78.7% fixed carbon and 64.3% organic carbon, with H/C org = 0.41 and O/C org = 0.31, indicating high aromaticity and chemical recalcitrance. The material showed a thermostable fraction of 83%, pH 7.8, electrical conductivity of 329.7 µS cm −1 , and a specific surface area of 67.75 m 2 g −1 . Concentrations of heavy metals and organic contaminants were below detection or within safety limits. The estimated carbon sequestration potential, derived from the H/Corg ratio, was 1.67 t CO 2 e t −1 of biochar, corresponding to an expected stability exceeding 100 years in soil. These results demonstrate that continuous horizontal pyrolysis is technically feasible at pilot scale, producing a stable, low-toxicity biochar with potential for long-term carbon storage. The findings highlight the suitability of this technology for industrial deployment and its relevance as a sustainable input for carbon removal and soil quality enhancement.