Co-liquefaction of mixed biomass feedstocks for bio-oil production: A critical review

Qingyin Li, Xiangzhou Yuan, Xun Hu, Erik Meers, Hwai Chyuan Ong, Wei Hsin Chen, Peigao Duan, Shicheng Zhang, Ki Bong Lee, Yong Sik Ok

Research output: Contribution to journalReview articlepeer-review

29 Citations (Scopus)


Liquefaction is an attractive technology for converting biomass into bio-oil without the requirement for drying feedstock, and the process can be conducted at relatively low temperatures. In the practical application, the treated biomass feedstocks are composed of a mixture of agricultural waste, forestry waste and some organic solid waste. The utilization of co-liquefaction technology is suitable for biomass as it can fully utilize different types of feedstocks and enhance the liquefaction degree of each feedstock. During the co-liquefaction of these blending biomass feedstocks, the individual biomass species can degrade according to their own reaction network that is governed by the unique structural compositions. Furthermore, the reaction intermediates from the degradation of different biomasses can potentially interact with each other. This will affect the reaction characteristics and alter the chemical constituents and properties of the bio-oil produced. The understanding of interaction for the blending biomasses during the co-liquefaction process is of significance for tuning the chemical species and yield of the resulting bio-oil. Thus, this review work focuses on the co-liquefaction behavior of the various biomass feedstocks including lignocellulose, organic solid waste and algae. The influences of the essential operation parameters including solvent types, catalyst types, reaction temperature and time, and the mixing ratio of different biomasses on co-liquefaction behavior are also evaluated in detail. The choice of the proper reaction parameters is dependent on the structural characteristics of mixed feedstocks. Additionally, the co-liquefaction impact on the composition and formation mechanism of bio-oils are investigated.

Original languageEnglish
Article number111814
JournalRenewable and Sustainable Energy Reviews
Publication statusPublished - 2022 Feb

Bibliographical note

Funding Information:
This work was supported by National Natural Science Foundation of China (No. 51876080), the Program for Taishan Scholars of Shandong Province Government , the Agricultural Innovation Program of Shandong Province ( SD2019NJ015 ), the R & D program of Shandong Basan Graphite New Material Plant and the Natural Science Fund of Shandong Province (ZR2019BB051).

Publisher Copyright:
© 2021 Elsevier Ltd


  • Alternative energy
  • Bio-oil
  • Biofuel
  • Biomass
  • Co-liquefaction
  • Synergistic effect

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment


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