ABSTRACT
Compared with strongly acidic molecular sieve catalysts, metal oxide catalysts are less prone to deactivation by coking due to their mild acid-base properties. Several metal oxides (Al2O3, MgO, CaO, CuO, Fe2O3, NiO, ZnO, ZrO2, TiO2 and CeO2) were selected for mild catalytic pyrolysis of lignin and compared with molecular sieve catalysts (MCM-41, HZSM-5, ZSM-5). Among the metal oxide catalysts studied, CuO, Fe2O3 and TiO2 inhibited the formation of acids/alcohols (1–2%) and promoted the production of hydrocarbons (15.31%, 20.17% and 28.83%, respectively). Especially when TiO2 catalyst was added, the proportion of hydrocarbons reached the highest (28.83%), but it inhibited the production of phenols (3.3%). The presence of CuO promoted the production of phenols (9.70%), showing a good deoxidation performance. Compared with the oxide catalysts, the addition of molecular sieve catalysts only resulted in 2 ~ 3% phenols. Compared with strongly acidic molecular sieve catalysts, metal oxide catalysts showed certain catalytic activity in deoxidation and cracking, and showed some advantages in the formation of phenols.
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The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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Notes on contributors
Xiaoting Xing
Xiaoting Xing is a M.Sc. in agricultural engineering from Shandong University of Technology, China. She is engaged in research on catalytic conversion and utilization of biomass.
Lei Liu
Lei Liu is a B.E. from the College of Agriculture and Food Science, Shandong University of Technology, China. His research interests include biomass utilization and renewable energy.
Yuchun Zhang
Yuchun Zhang is a researcher at Shandong University of Technology, China. She has done lots of research on the theory and method system of biomass directed conversion to fuel, promoted the theoretical and technological progress of biomass energization. Her main research interests are catalytic upgrading of biomass, CFD, multi-phase flow, biomass energy for hydrogen production.
Peng Fu
Peng Fu is a professor in Shandong University of Technology, China. He has published more than 50 research articles in international journals. His research interests are thermal conversion of biomass to produce oil and gas fuels, heat transfer, renewable energy.
Zhiyu Li
Zhiyu Li is a researcher at Shandong University of Technology, China. His research focuses on the efficient conversion of agricultural waste.