Kinetics of asphaltenes conversion during hydrotreating of Maya crude

The kinetics of asphaltene conversion was studied during the hydrotreating of Maya heavy crude oil. Experimental tests were conducted in a pilot plant at the following reaction conditions: total pressure of 70–100 kg/cm2, liquid hourly space-velocity (LHSV) of 0.33–1.5 h-1, and reaction temperature of 380–420 °C at a constant hydrogen-to-oil ratio of 5000 ft3/bbl. A commercial NiMo/Al2O3 catalyst was used in all experiments. Asphaltenes were precipitated from Maya crude and from hydrotreated products in a Parr Batch Reactor at 25 kg/cm2 and 60 °C with n-heptane as solvent. Asphaltene hydrocracking data were used to estimate reaction orders and activation energy using a power-law model, and the average absolute error between experimental and calculated concentrations of asphaltenes was found to be less than 5%.