Kinetic Model for Moderate Hydrocracking of Heavy Oils

In this work, a kinetic model for hydrocracking of heavy oils is proposed. The model includes five lumps:  unconverted resid (538 °C+), vacuum gas oil (VGO; 343−538 °C), distillates (204−343 °C), naphtha (IBP-204 °C), and gases. Kinetic parameters were estimated from the experimental results obtained in a fixed-bed downflow reactor. The proposed lump kinetic model fitted the data for hydrocracking of Maya heavy crude with a Ni/Mo catalyst at 380−420 °C reaction temperature, 0.33−1.5 h-1 liquid hourly space velocity, 5000 scf/bbl, and 70 kg/cm2. Only resid cracked to naphtha at 380 °C, but all heavier fractions produced some naphtha at higher temperature. The predicted product composition is in good agreement with experimental values with an average absolute error of less than 5%.