Production of high quality gasoline from waste polyethylene derived heavy oil over Ni-REY catalyst in steam atmosphere

Nickel and rate earth metal exchanged Y-type zeolite catalyst (Ni-REY) was prepared for producing light fuels (gasoline and kerosene) by the catalytic cracking of heavy oil from waste plastics in a steam atmosphere. The Ni in the catalyst was found to exhibit catalysis for transportation of hydrogen atoms from steam to hydrocarbons. In a steam atmosphere, strong acid sites of the catalyst, which usually cause excessive cracking, were covered with steam molecules, leading to a high yield of liquid fuels. Experiments using MFI zeolite in a nitrogen atmosphere were also conducted for comparison. During the repetition of sequences of reaction and regeneration of the catalysts, MFI zeolite was gradually deactivated, whereas Ni-REY was found to show constant activity. Furthermore, the selectivity towards gasoline was higher than MFI zeolite (Ni-REY in steam: 78%, MFI type zeolite in N-2: 35%). (C) 1999 Elsevier Science Ltd. All rights reserved.