Deep Conversion of Venezuela Heavy Oil via Integrated Cracking and Coke Gasification-Combustion Process

Abstract

© 2017 American Chemical Society. The integrated residue cracking and coke gasification-combustion (RCGC) process was proposed to make hierarchical and value-added utilization of Venezuela vacuum residue. Heavy oil cracking was conducted in a fluidized bed reactor with spent fluid catalytic cracking (FCC) catalysts, finding that both high liquid yield ( > 76 wt %) and conversion ratio ( > 90%) could be realized over the hydrothermal treated FCC (A-FCC) catalyst at 524 °C. As characterized by temperature-programmed ammonia desorption analysis, the A-FCC catalyst with moderate cracking ability was essential for optimum product distribution in vacuum residue conversion, where coke formation could be greatly suppressed via efficient oil vaporization and minimized secondary reaction. Coke removal (i.e., catalyst regeneration) of the FCC catalysts was conducted in two ways, that is, coke gasification (G-FCC) and gasification-combustion (GC-FCC). During coke gasification, the sum of H 2 and CO took up more than 80 vol % in the syngas, which could be potentially used as a hydrogen source for hydrotreating the cracked oil. Compared with that of the G-FCC catalyst, the regeneration time of the GC-FCC catalyst not only was shortened by 40% but also had higher carbon conversion ratio and a superior recovery of pore structures. As a result, the GC-FCC catalyst showed cracking performance for vacuum residue that was better than that of the G-FCC catalyst because of its higher recovered acidity for heavy oil conversion. The FCC catalyst exhibited good hydrothermal stability during the cycle tests and thus could be potentially used as a candidate for Venezuela heavy oil upgrading via the RCGC process.