A Hybrid FCC/HZSM-5 Catalyst for the Catalytic Cracking of a VGO/Bio-Oil Blend in FCC Conditions

Abstract

The performance of a commercial FCC catalyst (designated as CY) and a physically mixed hybrid catalyst (80 wt.% CY and 20 wt.% HZSM-5-based catalyst, designated as CH) have been compared in the catalytic cracking of a vacuum gasoil (VGO)/bio-oil blend (80/20 wt.%) in a simulated riser reactor (C/O, 6gcatgfeed−1; t, 6 s). The effect of cracking temperature has been studied on product distribution (carbon products, water, and coke) and product lumps: CO+CO2, dry gas, liquified petroleum gases (LPG), gasoline, light cycle oil (LCO), heavy cycle oil (HCO), and coke. Using the CH catalyst, the conversion of the bio-oil oxygenates is ca. 3 wt.% higher, while the conversion of the hydrocarbons in the mixture is lower, yielding more carbon products (83.2–84.7 wt.% on a wet basis) and less coke (3.7–4.8 wt.% on a wet basis) than the CY catalyst. The CH catalyst provides lower gasoline yields (30.7–32.0 wt.% on a dry basis) of a less aromatic and more olefinic nature. Due to gasoline overcracking, enhanced LPG yields were also obtained. The results are explained by the high activity of the HZSM-5 zeolite for the cracking of bio-oil oxygenates, the diffusional limitations within its pore structure of bulkier VGO compounds, and its lower activity towards hydrogen transfer reactions.

Pyrolytic lignin: a promising biorefinery feedstock for the production of fuels and valuable chemicals

“…35,36 An interesting application of the liquid fraction, either as such or after upgrading, is co-feeding with refinery streams like heavy gas oils and jointly upgraded in an oil refinery for the production of diesel, gasoline or LPG products. 37,38 The main objective of biomass fast pyrolysis is to obtain a liquid product in high yields, which is generally achieved at pyrolysis temperatures of ca. 500-550 °C.…”

“…35,36 An interesting application of the liquid fraction, either as such or after upgrading, is co-feeding with refinery streams like heavy gas oils and jointly upgraded in an oil refinery for the production of diesel, gasoline or LPG products. 37,38…”

The mathematical catalyst deactivation models: a mini review

“…ANNs are utilized to predict variables processed in a rapid manner and provide precise prediction under a complex process. ANNs are broadly applied for modeling and controlling multipart of chemical reactors and processes to accurately simulate atmospheric distillation columns, 131,132 various of heat exchangers, 133,134 and catalytic reactors. 135,136 Approximation of the reaction rate obtained without a kinetic model would eliminate the errors obtained from choosing of the kinetic method related to the catalyst deactivation models for kinetic constant integration.…”

Limitations in the energy balance when VGO/aqueous bio-oil mixtures are co-processed in FCC units

“…However, when 20 wt% of bio-oil is co-fed, the results are different, a decrease in gasoline yields being observed from 39 to 42 wt % in VGO cracking down to 36-38 wt% in mixture cracking [32]. Ibarra et al [33][34][35][36][37] studied the cracking of raw bio-oil together with VGO, showing synergy between the cracking mechanisms of oxygenates and hydrocarbons, as well as an important decrease in coke yield, given the water contributed by bio-oil to the reaction medium.…”

“…The stripping section between reactor and regenerator provides a countercurrent contact between steam at high temperature and catalyst particles aimed at removing volatile hydrocarbons adsorbed on the catalyst surface. It has also been shown in the conversion of bio-oil that moderate water concentrations attenuate coke deposition [33][34][35][36][37], thus allowing the catalyst to maintain higher activity. Consequently, it could be convenient to co-process bio-oils in refineries without previous dewatering.…”