Hydrocracking of Waste Plastic Pyrolysis Oil and Light Cycle Oil (PPO/LCO) Blends in a Trickle-Bed Reactor: Catalyst Assessment and Operating-Condition Screening

Abstract

Plastic waste management is a major challenge for our society. The use of refinery facilities offers the possibility of treating them neatly or blending them with refinery streams to obtain products suitable for adaptability to market requirements. In this sense, this work investigates the production of automotive fuels through the hydrocracking of a blend composed of plastic-derived pyrolysis oil (PPO) and light cycle oil (LCO). First, three catalysts (PtPd/HZSM-5, PtPd/HY, and NiW/HY) were tested to study the influence of their acid, metallic, and structural properties in the hydrocracking reactions. This was performed using a PPO/LCO blend (20:80 in mass) at 400 °C, 60 bar, H2:feed volumetric ratio, 2000:1, space-time, 0.23 g h gfeed–1, and time on stream (TOS), 8 h. The PtPd/HY catalyst exhibited good capacity for fuel production; its medium acid strength, superior hydrogenation capacity, and microporous structure favored gasoline production, reaching a selectivity of 81 wt %. With this catalyst, the effects of pressure and the amount of PPO in the blend were also assessed. At high pressures (80 bar), overcracking reactions were more likely to occur, while the conversion of heavy fractions remained constant. A similar trend was observed when the PPO loading was increased up to 40 wt %, the formation of light compounds was promoted to the detriment of the conversion of heavy fractions and gasoline formation.