(2025) Journal of Analytical and Applied Pyrolysis_Assessing carbon negative potential in CO₂-mediated pyrolysis of agricultural residue

Lee T.; Moon G.; Lee J.; Jang S.-H.; Tsang Y.F.; Kwon E.E.

(Elsevier B.V.) Journal of Analytical and Applied Pyrolysis ISSN: 1652370 Vol.192 Issue. Article No.107259 DOI: 10.1016/j.jaap.2025.107259

Wheat straw (WS), one of the most abundant agricultural residues, has garnered attention as a renewable alternative to petroleum-derived carbon resources. However, current biofuel production faces challenges in realizing efficient carbon use. To address this, pyrolysis offers a promising platform capable of converting all the carbon in WS into value-added pyrogenic products such as syngas, biocrude, and biochar. This study focused on enhancing carbon-negative potential of WS pyrolysis by incorporating carbon dioxide (CO₂) as partial oxidant and carbon resource. At temperatures ≥ 430˚C, CO_2 interacted homogeneously with volatiles pyrolyzed from WS and converted them into carbon monoxide (CO), contributing to carbon-negative character to the pyrolysis system. To accelerate the kinetics of CO₂-driven reactions, the pyrolysis setup was systematically modified by delivering an additional heat and introducing a nickel catalyst. Additionally, two process parameters (reaction temperature and CO₂ concentration) were tailored to optimize CO-rich syngas production. The energy requirements and net CO₂ emissions of CO₂-mediated catalytic pyrolysis were evaluated under optimal conditions. CO₂-mediated catalytic pyrolysis of WS demonstrated a carbon-negative potential of 1260 mg CO2 per gram of WS. Therefore, this finding offers opportunities to suppress 1235 million tons of CO₂ annually across the agricultural sector linked to wheat straw harvest. © 2025 Elsevier B.V.

This work was supported by the National Research Foundation of Korea (NRF) grants funded by the Korean Government (MSIT) (Grant No. RS-2023-NR077231 and RS-2024-00342766).