Pyrolysis of waste oil in the presence of a spent catalyst

• Spent Zeolite-like catalyst can be effectively used to degrade waste oil.
• The diesel oil yield was higher than 60% in the presence of a spent catalyst.
• The stability of the spent catalyst was maintained during the degradation of the waste oil.
• The productivity of diesel oil was higher than 1.4 g/h g of spent catalysts.
• The waste oil was treated using more than 11.7 g/g of spent catalyst.

A spent catalyst has great potential to convert waste oil into diesel oil. This study investigated the pyrolysis of waste oils in the presence of a spent catalyst, as well as the regeneration properties of the spent catalyst, such as the type of regeneration (in situ and ex situ) and time and temperature for spent catalyst regeneration. In addition, the effect of the spent catalyst, type of waste oil, weight ratio of the spent catalyst to the waste oil, and stability of the spent catalyst were evaluated. The yield of diesel oil was higher than 60% when waste oil was pyrolyzed at 370 °C.