Aurélie Largeau, Marion Carrier, Claudie Quertier, Robin Beghin, Nicolas Dietrich, Gilles Hébrard,
Characterization and lab-scale carbonation of wood biomass ashes: Exploring links between ash properties and CO2 capture,
Chemical Engineering Research and Design,
Volume 231,
2026,
Pages 532-544,
ISSN 0263-8762,
https://doi.org/10.1016/j.cherd.2026.06.021.
(https://www.sciencedirect.com/science/article/pii/S0263876226003862)
Abstract: Biogas from anaerobic digestion typically contains 30%–50% CO2, which must be removed to obtain grid-quality biomethane. Simultaneously, woody biomass combustion generates large amounts of alkaline ash (rich in Ca/Mg oxides) that remain poorly valorized despite their carbonation potential. This study provides a novel, systematic analysis of wood ash properties governing CO2 capture, using ashes from commercial boilers differing in combustion technology (e.g., moving grate vs. volcanic grate) and type (fly/bottom). Ashes were characterized (mineralogy, bulk and surface composition, basicity, particle size, morphology, Total Organic Carbon (TOC)/Total Inorganic Carbon (TIC)), and carbonated in a novel gas–liquid contactor (pure CO2, 6 bar, 100gL-1 suspensions). The best-performing ashes reached 328 g CO2/kg ash. Surface Ca content (Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS)) and basic site density (Temperature-Programmed Desorption (TPD)) correlated more strongly (R2 = 0.81 for TPD) with carbonation performance than bulk Ca content, establishing quantitative selection criteria for efficient ash valorization. These findings support coupling wood ash carbonation with biogas upgrading to simultaneously valorize biomethane and ash residues. Pilot-scale validation is needed.
Keywords: CO2 sequestration; Waste valorization; Alkaline residue; Mineral carbonation; Biogas upgrading; Shrinking-core
