Effects of oxygen concentration on the formation of heavy components in bio-oil during biomass oxidative pyrolysis

• Published in: Fuel
• Main Author: Liu Q.; Xiong Y.; Zhang C.; Wang X.; Syed-Hassan S.S.A.; Deng W.; Xu J.; Wang Y.; Su S.; Xiang J.
• Format: Article
• Language: English
• Published: Elsevier Ltd 2025
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85211087276&doi=10.1016%2fj.fuel.2024.134046&partnerID=40&md5=06bb2df77e7aee9accc5c53cff8113ea

Biomass oxidative pyrolysis has garnered significant attention for large-scale application of biomass in an autothermal regime. However, the presence of oxygen substantially influences the overall reactions and consequently affects the bio-oil, which is expected to become a viable alternative to petroleum. Heavy components (>200 Da) are active macromolecules in bio-oil and the main precursor of coke, which leads to reactor blockage and catalyst deactivation during the upgrading process. To investigate the effects of oxygen concentration on the evolution of heavy components in bio-oil, oxidative pyrolysis experiments of poplar were conducted at various oxygen concentrations (0–12 vol%). The results revealed that increased oxygen concentration boosted biomass depolymerization and the secondary cracking of volatiles, further influencing the creation of heavy components in bio-oil. Additionally, the generation of light components and aromatic substances was hindered. At a low oxygen concentration (4 vol%), oxygen impeded the formation of heavy components (<400 Da) and inhibited the creation of lipids and phenolic substances in heavy components. At high oxygen concentrations (>4 vol%), oxygen further promoted the formation of high molecular weight heavy components (>400 Da) with a high O/C ratio (>0.2). It also inhibited the creation of lipids and phenolic compounds in heavy components while promoting the formation of heavy sugars. © 2024 Elsevier Ltd