HYDROCRACKING OF A PLASTICS PYROLYSIS-GAS OIL TO NAPHTHA

Pyrolysis of waste plastics is one method currently being investigated as an alternative to landfill disposal of this increasingly large was te stream. Although the pyrolysis process produces significant quantit ies of Light naphtha range liquids, there is also a residual fraction that may be considered as a potential feedstock for upgrading. The obj ective of our research was to investigate the upgrading potential of t he gas oil fraction of a typical plastics pyrolysis Liquid using catal ytic hydrocracking, in this study, the residual fraction of a liquid p roduced by the pyrolysis of plastics, containing about 70%, +205 degre es C gas oil, was subjected to batch hydrocracking reactions. The reac tions used a commercial NiMo supported on zeolite-alumina catalyst and gave good conversion to naphtha. A simplified three-lump sequential r eaction pathway (gas oil --> naphtha --> gas) was applied to simulate the upgrading of the gas oil fraction to naphtha and gases. The kineti c model considered the variation in Ha partial pressure in the hydrocr acking rate expression and thereby was able to account for conversion and yield differences between large and small batch reactors. The mode l simulated the experimental data well including experimentally observ ed trends such as the maximum in naphtha yield at lower temperatures.