Catalytic hydropyrolysis of lignin: Suppression of coke formation in mild hydrodeoxygenation of lignin-derived phenolics

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 386; p. 121348
• Main Authors: Sirous-Rezaei, Pouya, Park, Young-Kwon
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.04.2020
• Subjects: Aromatic hydrocarbon; FeReOx/ZrO2; Hydropyrolysis; Lignin-derived phenolics; Mild hydrodeoxygenation; Moderate acid strength; FeReOx/ZrO2; Mild hydrodeoxygenation; Moderate acid strength; Lignin-derived phenolics; Aromatic hydrocarbon; Hydropyrolysis
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2019.03.224

[Display omitted] •In-situ catalytic hydropyrolysis of lignin using HY catalyst.•Ex-situ catalytic hydrodeoxygenation of lignin-derived phenolics at mild conditions.•Selective conversion of lignin into aromatic hydrocarbons.•FeReOx/ZrO2: a potential catalyst for mild HDO of lignin-derived phenolics. Lignin, with its polyaromatic structure and as a main component of lignocellulosic biomass, is considered as an important renewable source of aromatics which are currently obtained from fossil fuels. Lignin pyrolysis gives a liquid product with a high content of phenolic compounds which can be further upgraded to aromatic hydrocarbons through catalytic approaches. In this work, in-situ catalytic hydropyrolysis combined with a subsequent ex-situ catalytic hydrodeoxygenation step was implemented to achieve an enhanced conversion of kraft lignin into aromatic hydrocarbons. The main point is that the ex-situ catalytic upgrading was conducted at mild conditions (temperature: 350 °C; pressure: 1 atm). HY was used as in-situ catalyst for enhanced decomposition of lignin. Fe/HBeta, FeReOx/MCM-41, Fe/ZrO2 and FeReOx/ZrO2 were used as ex-situ catalyst, among which the oxophilic, mesoporous and mild-acidic catalyst of FeReOx/ZrO2 revealed the highest HDO efficiency. Importantly, FeReOx/MCM-41, Fe/ZrO2 and FeReOx/ZrO2 led to significantly lower yield of coke compared to a zeolite-supported catalyst like Fe/HBeta. This suppression of coke formation is a result of reduced phenolic trapping inside catalyst mainly due to the mesoporosity and moderate acid strength of catalyst.