Influence of Catalyst Acidity on Fine Particle Deposition during Hydrotreating of Bitumen-Derived Heavy Gas Oil
John Eleeza, Philip Boahene, V. Sundaramurthy, Ajay K. Dalai, John Adjaye
Abstract
The effect of catalyst acidity on fines deposition during hydrotreating of bitumen-derived heavy gas oil (HGO) was investigated in a batch reactor using a series of mesoporous NiMo/Ti–Al2O3 catalysts. Experimental design based on a three-factor optimal (custom) response surface methodology was performed and analyzed, considering temperature, catalyst acidity (Ti/Al), and asphaltene coatings in the ranges of 360–380 °C, 0–0.05, and 0–1084 ppm, respectively. The results of the experiments indicated that fines deposition was independent of the hydrotreating reaction temperature range of 360–380 °C. Additionally, lower deposition of fines was recorded with increasing catalyst acidity. In terms of asphaltene coating, fines with higher asphaltene coating showed higher deposition in the catalyst bed. Analysis of the spent catalyst showed a decrease in the weak acidic sites after hydrotreating. Finally, within the range of process parameters evaluated, a mathematical model with a correlation accuracy of 85% was developed to predict the extent of fines deposition with variable catalyst acidity. Models for hydrodesulfurization and hydrodenitrogenation with R2 values of 0.93 and 0.82, respectively, were also developed.