Thegarid, N., Fogassy, G., Schuurman, Y., Mirodatos, C., IRCELYON, ProductionsScientifiques, Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)
Due to the depletion of carbon fossil resources and increased efforts to mitigate CO2emissions, new generations of transportation fuels have recently been proposed, involving a partial or complete replacement of fossil resources by carbon-neutral renewable ones. As such, biomass is a promising feedstock since it is abundant and cheap and can be transformed into fuels and chemical products [1].A major challenge to consider is the required mass production given the huge capacities involved in transportation, which means that rapid change can be achieved only by using existing infrastructures and guaranteeing the same quality of final fuels. For that reason, a realistic scenario for bio-fuels mass production in the short term is to consider "co-processing" of biomass-derived resources together with conventional crude oil in standard refineries.Co-processing might allow refiners to adjust the content of bio carbon in the produced "hybrid" fuels at a level compatible with international regulations (e.g. EC regulation for 10% of renewable feedstock by December 2020 on energy content basis of “all petrol and diesel for transport purposes” [2]). Fluid Catalytic Cracking (FCC) is one of the most important processes of a modern refinery because of its flexibility to changing feedstock and product demands. Its principal aim is to convert high molecular weight hydrocarbons to more valuable products mainly gasoline [3]. Inthe present work, we investigate how co-feeding Vacuum Gasoil (VGO) with pre-treated pyrolysis-oil in a fixed bed reactor can influence the product distribution and the product quality.To simulate co-processing in a FCC unit, a mixture of 80% of pure VGOand 20 wt.% of up-graded (partly deoxygenated and low water content) bio-oil (referred to as HDO-oil) was co-injected and processed in a fixed bed reactor. The gasoline fraction is the primary objective of a FCC unit. Co-feeding HDO-oil gave comparable yields for gasoline to those corresponding to the cracking of pure VGO. Detailed compositions of the gasoline at a given conversion (~85%) are compared in Figure 1 for VGO and VGO/HDO-oil. Full conversion of oxygenates remains challenging since their residual concentration must fulfil environmental requirements. No significant activity loss was noted for the e-FCC catalyst after co-processing sequence, tending to demonstrate close quality in coke formation and combustion.Co-processing favors much more branched paraffin formation to the expenses of paraffins as compared to the pure VGO cracking. Short alkyl chain (C1-3) benzene derivatives are more typical for the VGO/HDO feed than for the pure VGO cracking. Mechanistic studies point in the direction of a change in the acid sites distribution and to the consumption of hydrogen by HDO-oil conversion. The latter would limit hydrogen transfer processes for the VGO cracking process and favor aromatics at the expenses of saturated products.Figure 1. Gasoline detailed composition by compounds at ~85% conversion level based on GCxGC analysis.[1] G. H. Huber, A. Corma, Angew. Chem. Int. Ed., 46 (2007) 7184–720.[2] A. Oasmaa, D. Meier, “Fast Pyrolysis of Biomass: A Handbook”, Vol. 2, CPL Press, Newbury, UK (2002) 41-58.[3] C. N. Hamelinck, A. P. C. Faaij, H. dem Uil, H. Boerrigter, Energy, 29(11) (2004) 1743-1771.