Hydrotreating represents one of the most important catalytic processes in the petroleum refinery industry. Besides being mainly used to upgrade heavy oils, it serves as the pretreatment step for several feeds that undergo downstream refining processes. Several challenges are encountered during the hydroprocessing of bitumen-derived heavy gas oils owing to their high concentrations of organosulfur and nitrogen compounds as well as asphaltenes. Investigations into catalyst deactivation due to these impurities have been the common industrial challenge of focus. However, in-depth research into fouling resulting from deposition of solid fine particles of heavy gas oil on the catalyst bed and its impact on pressure drop build-up in packed-bed reactors is equally crucial in heavy oil upgrading. Beyond the maximum allowable operating pressure of the reactor, a premature shutdown and subsequent replacement of expensive hydrotreating catalyst become inevitable due to plugging and pressure drop growth; thus, impacting negatively on the economics of the hydrotreating process. In this work, the effects 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 sulfide catalysts. Experimental design based on a 3-factor optimal response surface methodology was performed and analyzed considering reaction temperature, catalyst acidity, and asphaltene coated fine solid content in the ranges of 360–380°C, 0–0.05 and 0–1084 ppm, respectively. The results of experiments indicated that fines deposition on the catalyst was independent of the hydrotreating reaction temperature. With increasing catalyst acidity, a decrease in deposition of fines was observed. Analysis of the spent catalyst showed chemisorption of fine particles on NiMo/Ti-Al2O3 catalyst. Finally, within the range of process parameters evaluated, a mathematical model with a correlation accuracy of 85% was also developed to predict the extent of fines deposition with variable catalyst acidity.

Influence of catalyst acidity on fine particles deposition during hydrotreating of bitumen-derived heavy gas oil

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.