Comparative Study of Different Atmospheres for a Ptpd/y Catalyst Regeneration for Plastics /VGO Hydrocracking

Abstract

The valorisation of post-consumer plastics by co-feeding them to hydrocracking units has been gaining attention due to their feasibility to produce automotive-like fuels with a composition suitable for commercial use. For this purpose, the use of noble metal-based catalysts is advised due to their high selectivity towards these fractions and high hydrocracking activity. In this context, the reuse of such catalysts should be explored to avoid expensive operating costs. This work explores different regeneration atmospheres of a PtPd/Y zeolite catalyst used in the hydrocracking of polystyrene (PS)/vacuum gasoil (VGO) blends (10 wt%) under the following conditions: 400 °C, 80 bar, 180 min, catalyst/feed ratio: 10 wt%. Regeneration has been carried out under oxidizing, reducing and gasifying conditions using oxygen, hydrogen and CO2 as regenerating agents. The results reveal that only controlled combustion provides efficient catalyst regeneration, yielding almost the same yield distribution and chemical composition of the liquids, with less than a 5 wt% difference in both cases. The activity decay is attributed to irreversible causes of deactivation that are minimal in the actual process, thus encouraging the adoption of this valorisation pathway for the exploitation of crude resources in terms of maximizing refinery conversion while promoting the Waste Refinery.