Influence of the Composition of Raw Bio-Oils on Their Valorization in Fluid Catalytic Cracking Conditions

Abstract

This study delves on the catalytic cracking in fluid catalytic cracking (FCC) conditions of two raw bio-oils of different compositions, obtained from the fast pyrolysis of pine sawdust (PBO) and black poplar sawdust (BPBO). The FCC runs have been carried out using an equilibrated FCC catalyst at 550 °C, 6 s of contact time and in the C/O (catalyst/bio-oil) range of 1.8–10 gcat (gfeed)−1. The effect of the C/O ratio has been studied on product distribution (CO + CO2, carbon products, water, and coke); on the yields of CO + CO2, dry gas (C1–C2), liquefied petroleum gases (C3–C4), gasoline (C5–C11), light cycle oil (C12–C22), and coke; on the conversion of specific bio-oil oxygenates; and on the hydrocarbon and oxygenates composition of the gasoline product. A gasoline yield of 45.7 wt % was achieved, with a hydrocarbon yield of 29.6 wt % and a liquid fraction (C5–C20) yield of 13.8 wt % at C/O = 7.3 gcat (gfeed)−1. The differences in the results of both bio-oils can be explained from their different compositions in terms of oxygenates and water. These factors have a great incidence on coke deposition and also explain the differences in the total conversion of oxygenates, hydrocarbon yield, composition of the gasoline fraction, and individual conversion of each oxygenate family.