Different approaches to convert waste polyolefins into automotive fuels via hydrocracking with a NiW/HY catalyst

Abstract

Different approaches to upgrade waste plastic and vacuum gasoil (VGO) blends via hydrocracking have been investigated. The approaches have consisted on using different charges: (i) neat VGO; (ii) neat plastic pyrolysis oil (PPO); (iii) a PPO/VGO blend; (iv) a high-density polyethylene (HDPE)/VGO blend; and (v) a ternary PPO/HDPE/VGO blend. The runs have been conducted in a batch reactor at: 400–440 °C; 80 bar; catalyst to oil mass ratio, 0.1 gcat gcharge−1; and reaction time, 2 h. Obtained products have been grouped in different lumps, which are defined according to their boiling point range: gas, naphtha, light cycle oil (LCO), heavy cycle oil (HCO), wax (unconverted plastic) and coke. The concentration of the families of compounds (n-paraffins, isoparaffins, olefins, naphthenes and aromatics with 1, 2 and 3+ rings) has been also determined. Results expose that composition of products is improved with respect to that obtained in the hydrocracking of VGO with both binary and ternary blends. The naphtha and LCO obtained in the hydrocracking of PPO/VGO and PPO/HDPE/VGO blends have a lower concentration of aromatics than the lumps of the VGO, making them more attractive to be added to the pools of fuels in refinery.