Catalytic upgrading of heavy oil over mesoporous HZSM-5 zeolite in the presence of atmospheric oxygen flow

Abstract

Alkaline treated ZSM-5 zeolite was used in heavy oil upgrading process under atmospheric oxygen flow. Alkaline treatment was employed to induce mesopores in ZSM-5 catalyst structure to alleviate the mass transfer and reduce diffusion limitations. XRD, BET and XRF analyses were employed to investigate the effect of alkaline treatment. Effect of oxygen atmospheric flow, supplied by air stream, on heavy oil catalytic cracking process was investigated in a fixed bed reactor. Obtained liquids were analyzed by FTIR and GC/SIMDIS. Results revealed that percent of light oil (naphtha + kerosene) produced was nearly doubled in the presence of 5 wt% oxygen in the feed. Conversion of heavy oil (content with the BPT higher than 370 °C) was enhanced from 45.7% up to 58.1% by applying air stream. Viscosity reduction was elevated from 40% in nitrogen atmosphere to 53% in presence of 5 wt% oxygen content. Spent catalysts were characterized by TGA, XRD and BET analyses in order to determine coke deposition and catalyst structural stability. Oxidative cracking increased the amount of coke production over the catalyst, however, structural stability of the catalyst was not altered compared to conventional cracking process and crystalline structure of the catalyst was preserved after 5 h time on stream.