Continuous-flow production of petroleum-replacing fuels from highly viscous Kraft lignin pyrolysis oil using its hydrocracked oil as a solvent. (1st June 2020)

• Record Type: Journal Article
• Authors: Kim, Yoonsoo; Shim, Jingi; Choi, Jae-Wook; Jin Suh, Dong; Park, Young-Kwon; Lee, Ung; Choi, Jungkyu; Ha, Jeong-Myeong
• Is Part Of: Energy conversion and management. Volume 213(2020)
• Publication Date: 2020-06-01
• Subjects: Lignin pyrolysis oil -- Hydrocracking -- CoMo/Hβ -- Viscosity -- Hydrodeoxygenation; Direct energy conversion -- Periodicals; Energy storage -- Periodicals; Energy transfer -- Periodicals; Énergie -- Conversion directe -- Périodiques; Direct energy conversion; Periodicals; 621.3105
• DOI: 10.1016/j.enconman.2020.112728
• Languages: English
• ISSNs: 0196-8904

Abstract

Graphical abstract: Highlights: Lignin pyrolysis oil or lignin oil was hydrocracked to less-viscous liquid products. Oligomers and oxygen functionalities were removed over CoMo/Hβ or CoMo/Al2 O3 . Low viscosity (3.2 cP), high yield (72.3%), and low coke yield (1.2%) were obtained. Hydrocracked liquid dissolved lignin oil with the high solubility. Continuous flow reaction was successful using lignin oil in hydrocracked liquid. Abstract: The development of solvent-free lignin pyrolysis processes is highly desirable, because these processes would allow the depolymerized product to be used directly as a renewable energy source and chemical feedstock, without removal of solvnets. However, this product is typically highly viscous and cannot be used in continuous-flow reaction systems. In this study, lignin pyrolysis oil was prepared from Kraft lignin using bench-scale fixed-bed batch pyrolysis and then hydrocracked to produce less-viscous liquid products. Oligomers were degraded into smaller molecules via reactions involving hydrogen (hydrocracking) using CoMo/Hβ and CoMo/Al2 O3 as catalysts. A low viscosity of 21 cP, a liquid yield of 76.6%, and a low coke yield of 1.6% were successfully attained using a reaction temperature of 400 °C, a reaction time of 60 min, and the CoMo/Hβ catalyst. Thus, these conditions were selected to achieve the highest liquid yield with sufficient fluidity, although the lowest viscosity of 3.2 cP was achieved after 240 min. When 30 wt% of the resulting hydrocracked oil was used, it dissolved sticky raw lignin pyrolysis oil, significantly reducing its viscosity from 751 cP to 111 cP, which is sufficient to ensure flow in a typical petroleum pipeline. Using the hydrocracked/raw lignin pyrolysis oil mixture, the proposed continuous-flow hydrodeoxygenation successfully produced petroleum-replacing deoxygenated fuels.