Catalytic hydrotreatment of fast pyrolysis liquids in batch and continuous set-ups using a bimetallic Ni-Cu catalyst with a high metal content

摘要

In this paper, an experimental study on the hydrotreatment of fast pyrolysis liquids is reported in both batch and continuous set-ups using a novel bimetallic Ni-Cu based catalyst with high Ni loading (up to 50%) prepared by a sol-gel method. The experiments were carried out in a wide temperature range (80-410 degrees C) and at a hydrogen pressure between 100-200 bar to determine product properties and catalyst performance as a function of process conditions. To gain insight into the molecular transformations, the product oils were analysed by GC x GC, H-1-NMR and GPC and reveal that the sugar fraction is reactive in the low temperature range (300 degrees C). In addition, the organic acids are very persistent and reactivity was only observed above 350 degrees C. The results are rationalized using a reaction network involving competitive hydrogenation of reactive aldehydes and ketones of the sugar fraction of fast pyrolysis liquids and thermal polymerisation. In addition, relevant macro-properties of the product oils including flash point (30 to 80 degrees C), viscosity (0.06 to 0.93 Pa s) and TG residue (<1 to about 8 wt%) were determined and compared. Product oils with the lowest oxygen content (< 13 wt%) were obtained in the continuous set-up at 410 degrees C.