Catalytic Cracking of C2–C3 Carbonyls with Vacuum Gas Oil

Abstract

The fluid catalytic cracking (FCC) route could be considered for the co-processing of biomass-derived pyrolysis oil with petroleum-derived vacuum gas oil (VGO) in a typical refinery unit by integrating it with a biomass fast pyrolysis process. This paper aims to study the effect of co-processing pyrolysis oil representative model compounds (C2–C3 carbonyls such as hydroxyacetone and glycolaldehyde dimer) with VGO in a FCC advanced cracking evaluation (ACE-R) unit, using an industrially available FCC equilibrium catalyst (E-CAT). The blending ratios of C2–C3 carbonyls and VGO were varied from 5:95, 10:90, 15:85, and 20:80. The reactor was operated in close to industrial FCC process at a temperature of 530 °C and atmospheric pressure with a catalyst-to-oil ratio of 5.0. The blended FCC feedstock and their liquid distillates were structurally characterized by 1H and gated decoupled 13C NMR techniques. The average structural parameters like branchiness index, substitution index, average length of alkyl chains, and fraction of aromaticity per molecule was obtained from NMR data. A linear increase in FCC conversion was observed with increase in hydroxyacetone blending ratio with VGO from 5% to 20%, which may be due to an increase in propylene and a decrease in heavy cycle oil. Increasing the glycolaldehyde blending ratio from 5% to 10% increased the FCC conversion, while the conversion decreased at ratios of 15% and 20%. The 1H NMR and 13C NMR data indicated that there is an increase in the amount of monoaromatics with increases in the amount of hydroxyacetone, whereas in the case of glycolaldehyde, the monoaromatics increased for blending ratios up to 10% and decreased upon further increases in blending ratio. The equilibrium FCC catalyst is capable of cracking oxygenates presents in pyrolysis oil such as hydroxyacetone and glycolaldehyde toward the production of liquefied petroleum gas (LPG) range products. Furthermore, a scheme has been proposed for the processing of pyrolysis oil in petroleum refinery units.