Catalytic Upgrading of Iranian Vacuum Residue on Alkali-treated ZSM-5 Zeolite: Viscosity Reduction

ZSM-5 zeolite was alkali treated by NaOH solution in order to induce intracrystal mesoporosity via desilication. Prepared catalyst was tested in thermo-catalytic upgrading of vacuum residue (VR), a two-step process in which VR was thermally cracked at first stage then the pyrolysis vapors were in situ transferred to catalytic cracking step in a fixed bed reactor loaded with catalyst powder. Silica bead, microporous HZSM-5 and mesoporous HZSM-5 were tested in this process in order to investigate the effect of mesoporosity on attaining more valuable liquid product. The results showed that mesoporous catalyst reduced liquid product viscosity by 42.7% compared to product of thermal cracking of VR. This reduction was 23.8% and 8.9% for microporous HZSM-5 and silica bead, respectively.