Prediction of Sulfur Content, API Gravity, and Viscosity Using a Continuous Mixture Kinetic Model for Maya Crude Oil Hydrocracking in a Slurry-Phase Reactor

A continuous mixture kinetic model was applied to describe the hydrocracking reactions of Maya crude oil in a slurry-phase reactor. Besides the prediction of simulated distillation curves, complementary models were developed to predict American Petroleum Institute (API) gravity, viscosity, and total sulfur content as the reaction proceeds. Experiments were carried out in a batch-type reactor under 800 psig of hydrogen and 400 °C at several reaction times. Powder ammonium heptamolybdate (1000 ppm Mo) was added and activated in situ. Vacuum residue (VR) conversion reached 88 and 96% after 7.5 and 24 h of reaction, respectively. The formation of liquid products (bp < 538 °C) was maximum and fairly constant (65–66 wt %) for VR conversions from 37 to 88%. Feed and liquid reaction products were characterized by thermogravimetric analysis (TGA). Total sulfur, viscosity, and API gravity were also measured. The mathematical model accurately describes TGA distillation curves for VR conversions up to 88%, and the developed models for the calculation of sulfur content, viscosity, and API gravity predict with good accuracy the values of these properties.