Comparative analysis of the effects of hydrogen and formic acid on the vacuum residue hydrocracking

Abstract

The improvement of the existing technologies aimed at deeper processing of heavy oils and oil residues and development of new ones is an urgent task of modern oil refining. Experiments in a flow installation using a quartz reactor were performed to determine the formic acid decomposition pathway. The experiments showed that the formic acid decomposition over the Ni-Mo/Al2O3 catalyst predominantly yielded hydrogen and CO2. Therefore, in this study comparative experiments on the effects of hydrogen and formic acid on the vacuum residue hydrocracking in the presence of the Ni-Mo/Y-Al2O3 and Ni-Mo/Al2O3 catalysts were performed at 375–400 °C and 0.45 MPa pressure. The concentration of hydrogen or formic acid in argon was 10 vol%. The catalysts were prepared by impregnation of the corresponding supports with the aqueous solution obtained using nickel hydroxide, ammonium heptamolybdate and citric acid. Electron microscopy and XRD studies of the Ni-Mo/Y-Al2O3 and Ni-Mo/Al2O3 catalysts demonstrated that the active component in the studied catalysts was in a finely dispersed state. The size of Ni-Mo particles was 0.4–0.6 nm in the Ni-Mo/Y-Al2O3 catalyst and 0.3–0.6 nm in Ni-Mo/Al2O3. For both catalysts Ni-Mo/Y-Al2O3 and Ni-Mo/Al2O3 higher vacuum residue conversion to liquid products was observed in the presence of formic acid than in the presence of hydrogen. Hydrogen substitution for formic acid vapor during the vacuum residue hydrocracking also results in the lower sulfur content in the liquid reaction products. The use of formic acid as a hydrogen donor significantly simplifies the process hydrocracking.