Implications of feeding or cofeeding bio-oil in the fluid catalytic cracker (FCC) in terms of regeneration kinetics and energy balance

Abstract

Feeding or cofeeding bio-oil (biomass pyrolysis oil) into the fluid catalytic cracking (FCC) has a direct impact on product distribution, reaction kinetics and deactivation of this key catalytic valorization strategy. In this work, we have analysed the impact in terms of the catalyst regeneration kinetics and energy balance of the unit. These factors are linked to the holistic viability of revamped refineries turned into biorefineries. Deactivated catalysts were obtained in FCC experiments using vacuum gasoil and raw bio-oil. The regeneration kinetics of coke combustion were analysed in a thermobalance, whereas the heats dissipated throughout the combustion (high heating values) were analysed in a calorimeter. Overall, the regenerator does not require major design amendments to treat bio-oil. We found a linear correlation between the higher heating value of the reactants and the coke produced, which enables to predict possible scenarios in the FCC unit. When incorporating higher amounts of bio-oil, the heat balance of the unit changes significantly: the temperature in the regenerator rises up to +36 K, requiring significant energy input for heating the bio-oil but offering the chance to recover more (electrical) energy when the proportion of bio-oil is greater than ca. 50%.