Morphology effect on catalytic performance of ebullated-bed residue

Worldwide petroleum refining industry is entering a significant era of growing demand for light distillates and declining demand for heavy oils due to the depletion of traditional light crude oils. Therefore, the efficient upgrading of vacuum residue by catalytic hydroprocessing is of great importance.

Catalyst morphology is an important factor affecting vacuum residue hydrotreating performance, and elucidating the effect of morphology on industrial hydrotreating performance by experimental methods has been explored. However, the intrinsic morphology effect based on kinetic modeling is still missing. In a study published in the KeAi journal Green Chemical Engineering, a group of researchers from China develop a facile kinetic model to address this challenge.

Prof. Xiang Feng from the State Key Laboratory of Heavy Oil Processing in China led the research. He explains: “Analyzing the influence of catalyst morphological factors on hydrotreating performance by experimental methods and characterization is easy to achieve, however, it is not easy to achieve this goal by pure kinetic simulation. Firstly, we obtained over 1600 hours of residue hydrotreating performance of spherical and cylindrical Ni-Mo/Al₂O₃ catalysts from the industry, which provides a rich data base for kinetic calculations. Then, we improved the traditional lumped kinetic model by giving new meaning to the kinetic parameters, so that we can successfully bridge the visible catalyst morphology and the invisible impurity removal capability through kinetic simulations, thus indirectly analyzing the morphological effects of the catalyst from the fitted parameters.”

From the analysis of the kinetic parameters obtained from the simulation, it is clear that the percentage of light impurities on spherical catalysts were 78.20% and 39.43% in hydrodemetallization and hydrodeconradson-carbon-residue reactions, respectively, higher than 65.20% and 17.50% on cylindrical catalysts. Such data cannot be obtained through experiments and in accordance with previous industrial experimental and molecular dynamics simulation results, the kinetic modeling revealed that spherical catalysts are more capable of removing impurities than cylindrical catalysts, thus showing better hydrotreating performance.

Prof. Feng concludes: “This work analyzes the effect of catalyst morphology on catalytic performance by kinetics, and this strategy of visual data analysis can also be used in other industrial catalysis fields.”