Hydrothermally stable HZSM-5 zeolite catalysts for the transformation of crude bio-oil into hydrocarbons

The hydrothermal stability of two alternative catalysts for the production of hydrocarbons from crude bio-oil has been studied. The valorisation of crude bio-oil from lignocellulosic biomass pyrolysis has been studied by means of a two-step process (thermal-catalytic) and co-feeding methanol, which are strategies that attenuate both the deposition of pyrolytic lignin and catalyst deactivation by coke deposition. A catalyst prepared based on a HZSM-5 zeolite with a SiO(2)/Al(2)O(3) ratio of 80 produces a C(2)-C(4) olefins yield of 32 wt% at 500 degrees C and with a space time of 0.371 (g of catalyst) h (g of oxygenates)(-1). The modification of a HZSM-5 zeolite (SiO(2)/Al(2)O(3) ratio of 30) by impregnation with 1 wt% of Ni produces a yield of aromatics of 42 wt% for the same temperature and space time. These catalysts are very active for bio-oil valorisation (conversion above 90%) with high hydrothermal stability, given that their kinetic behaviour is similar throughout 10 successive reaction-regeneration cycles carried out under severe operating conditions. (C) 2010 Elsevier B.V. All rights reserved.