Catalytic Steam Cracking of Heavy Oil in the Presence of Molybdenum- and Nickel-Containing Nanodisperse Catalysts

Abstract

The process of catalytic steam cracking (CSC) of heavy oil with high contents of sulfur (4.3 wt %) and high-boiling fractions (>500 °C) was studied in the presence of Mo- and Ni-containing nanodisperse catalysts under static conditions (autoclave) at 425 °C. Experimental studies of thermal and steam cracking, as well as of water-free catalytic cracking were carried out for comparison and identification of specific features of CSC. Dependencies of the composition and properties of the liquid and gaseous products on the process conditions, catalyst nature and the presence of water were determined. It was established that the application of Ni-catalysts for CSC causes an increase in the H : C ratio (1.69) in the liquid products against that of the other cracking processes, while the yields of coke and gaseous products increase that results in a decrease in the liquid product yield. With the Mo-catalyst, the produced low-viscous semisynthetic oil is characterized by a higher H : C ratio (1.70 wt %) and the lowest sulfur content (2.8 wt %) in the liquid products. XPS and HRTEM studies of the catalyst-containing solid residue (coke) revealed that in CSC nickel is as well-crystallized nanoparticles Ni 9 S 8 of 15–40 nm in size, and molybdenum as two phases MoO 2 and MoS 2 at the ratio depending on the conditions of heavy oil transformation. The data obtained demonstrate that CSC is a promising process of upgrading heavy oil.