Effects of temperature and urea concentration on nitrogen-rich pyrolysis: Pyrolysis behavior and product distribution in bio-oil

• Published in: Energy (Oxford) 2022-01, Vol.239, p.122443, Article 122443
• Main Authors: Liu, Shanjian, Zhao, An, He, Zhisen, Li, Yongjun, Bi, Dongmei, Gao, Xin
• Format: Article
• Language: English
• Subjects: Aldehydes; Benzene; biofuels; Biomass; energy; Heterocyclic compounds; Hydrocarbons; Ketones; Nitrogen; Nitrogen heterocyclic compounds; Nitrogen-rich pyrolysis; Oil; Phenolic compounds; Phenols; pyridines; Pyrolysis; temperature; Temperature effects; Urea; Ureas
• ISSN: 0360-5442; 1873-6785
• DOI: 10.1016/j.energy.2021.122443

Nitrogen-rich pyrolysis is an important means of biomass utilization. In this paper, the effects of urea concentration and pyrolysis temperature on the composition of various nitrogen- and oxygen-containing compounds in bio-oil produced during the pyrolysis of pine powder (PP) were studied. The results showed that A-type (a benzene ring with one methoxy group) and B-type (a benzene ring with two methoxy groups) phenols were only detected in the bio-oil derived from conventional biomass pyrolysis. After nitrogen-rich pyrolysis, the total phenolic content in the bio-oil increased significantly, and all four types of phenols (A, B, C (a benzene ring featuring an alkyl group that is not a methoxy group), and D (other types of phenols)) were detected. In addition, the aldehyde and linear chain ketone contents in the bio-oil significantly decreased after nitrogen-rich pyrolysis compared to after conventional biomass pyrolysis. When the urea concentration was 10 wt%, only cyclic ketones were detected in the bio-oil. Furthermore, the content of nitrogenous heterocyclic compounds in the bio-oil significantly increased after nitrogen-rich pyrolysis when the urea concentration increased from 5 wt% to 10 wt%, with pyridine being the most abundantly produced. •Nitrogen-rich pyrolysis is an important means of biomass utilization.•Co-pyrolysis of pine and urea decreased activation energy of pine pyrolysis reaction.•Increasing urea enhanced nitrogen-containing heterocyclic compounds in bio-oil.•Total phenolic content increased significantly after nitrogen-rich pyrolysis.•Contents of aldehydes and linear chain ketones from nitrogen-rich pyrolysis was few.