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Communication Dans Un Congrès Année : 2021

Catalytic upgrading of pyrolysis vapors using mixed metal oxides

Résumé

An alternative to reduce fossil fuels dependency without heavy investment on new refineries is co-processing bio-oils derived from lignocellulosic biomass with conventional fossil feedstocks. However, the integration of bio-oil in this process faces some technical difficulties such as their high oxygen content, low miscibility with hydrocarbon fuels, low chemical stability and high acidity [1]. Therefore, it is necessary to improve bio-oil quality before using it to produce fuels. One possible option to upgrade the bio-oil quality is to produce it in an integrated catalytic pyrolyser, where the biomass conversion is carried out in the presence of an heterogeneous catalyst, such as ZSM-5 [2]. However, zeolites are susceptible to the deactivation, impacting on operational costs of process and reducing its competitiveness compared with fuel production from exclusively fossil feedstocks [3]. As an alternative for traditional catalysts, metal oxides can show acidic characteristics and good resistance to coke formation. Among them, niobium-based oxides has been studied for heterogeneous catalysis [4], but it has not been widely explored for upgrading of pyrolysis vapors. Thus, the aim of this work was to evaluate the impact of different niobium-based metal mixed oxides on the conversion of wood pyrolysis vapors employing an ex-situ catalytic system. These mixed oxides with different acidities were compared to a reference catalyst (ZSM-5). Three catalysts based on niobium oxide doped with another metal oxide (W, Al or Mn) were prepared and characterized. Pyrolysis of beech wood chips and catalytic conversion of the vapors were carried out in a laboratory-scale fixed-bed reactor equipped with a semi-continuous biomass dispenser. The gas phase was analyzed on-line using a µGC. The organic and aqueous phases of condensed bio-oil were separated by centrifugation. The organic phase was characterized by Karl-Fischer titration, elemental analysis (CHNS), GC-MS and 13C-NMR. Promising results were obtained for the treatment of pyrolysis vapors. One of the prepared catalysts exhibited equivalent catalytic performances, when compared to ZSM-5, in terms of liquid phase selectivity and reduction of oxygen content in the organic phase, which is directly related to the reduction of compounds that results in instability and immiscibility for bio-oils with traditional oil feedstocks. Modifications are planned to improve the activity of these metal-mixed oxides. Acknowledgements: This project has received funding from the European Unions’ Horizon 2020 research & innovation programme under grant agreement N° 818120. References [1]Md. M. Rahman, R. Liu, and J. Cai, Fuel Processing Technology 180, 32 (2018). [2]G. Yildiz et al., Renewable and Sustainable Energy Reviews 57, 1596 (2016). [3]A. V. Bridgwater, Biomass and Bioenergy 38, 68 (2012). [4]P. Yang et al., Applied Catalysis B: Environmental 239, 114 (2018).
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Dates et versions

hal-03229165 , version 1 (18-05-2021)

Identifiants

  • HAL Id : hal-03229165 , version 1

Citer

W. de Rezende Locatel, N. Guilhaume, D. Laurenti, Y. Schuurman. Catalytic upgrading of pyrolysis vapors using mixed metal oxides. e-PYRO 2021, Apr 2021, Virtuel, Belgium. ⟨hal-03229165⟩
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