Recent advances in lignocellulosic biomass valorization for producing fuels and commodities (olefins and BTX aromatics) are gathered in this paper, with a focus on the conversion of bio-oil (produced by fast pyrolysis of biomass). The main valorization routes are: (i) conditioning of bio-oil (by esterification, aldol condensation, ketonization, in situ cracking, and mild hydrodeoxygenation) for its use as a fuel or stable raw material for further catalytic processing; (ii) production of fuels by deep hydrodeoxygenation; (iii) ex situ catalytic cracking (in line) of the volatiles produced in biomass pyrolysis, aimed at the selective production of olefins and aromatics; (iv) cracking of raw bio-oil in units designed with specific objectives concerning selectivity; and (v) processing in fluidized bed catalytic cracking (FCC) units. This review deals with the technological evolution of these routes, in terms of catalysts, reaction conditions, reactors, and product yields. A study has been carried out on the current state-of-knowledge of the technological capacity, advantages and disadvantages of the different routes, as well as on the prospects for the implementation of each route within the scope of the Sustainable Refinery. /jctb 2 -C 4 olefins 147 a % Relative area: Percentage of total peak area detected by GC/MS semi-quantitative analysis.

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This study deals with a continuous process on a calcined dolomite operating at atmospheric pressure and by co-feeding water for cost-effective upgrading of raw bio-oil at 400 ºC and 500 ºC. The distribution of carbon in the feed to the product fractions (gas and upgraded bio-oil) and to the dolomite (as CO2 captured and coke) was investigated with time on stream, as well as the evolution of the gas and the upgraded bio-oil composition. Acids and high-molecular weight phenols were completely removed from the raw bio-oil for 0.5 h time on stream, with the upgraded bio-oil being mainly composed of ketones (acetone, 2-butanone and cyclopentanones). Chromatographic analyses of the reaction products were combined with analysis of the dolomite characteristics by thermogravimetry and X-ray diffraction. The results are explained on the basis of possible reaction mechanisms on the dolomite basic sites (CaO, Ca(OH)2 and MgO) and the extent of dolomite carbonation with adsorbed CO2. The composition of the upgraded bio-oil is suitable for subsequent catalytic valorization for obtaining fuels and chemicals, and in particular for the production of hydrogen by steam reforming.

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