October 2018 — F.G. Ciapetta Award Lecture
Dr. Teh C. Ho
Hydrocarbon Conversion Technologies
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Abstract: Hydrodesulfurization catalysts have two types of active sites for hydrogenation and hydrogenolysis reactions. While hydrogenation sites are more active for desulfurizing refractory sulfur species, they are more vulnerable to organonitrogen inhibition than hydrogenolysis sites. In contrast, hydrogenolysis sites are less active for desulfurizing refractory sulfur species but are more resistant to organonitrogen inhibition. This dichotomy is exploited to develop an ultra-deep hydrodesulfurization stacked-bed reactor comprising two catalysts of different characteristics. The performance of this catalyst system can be superior or inferior to that of either catalyst alone. A theory is developed to predict the optimum stacking configuration for maximum synergies between the two catalysts. The best configuration provides the precise environment for the catalysts to reach their full potentials, resulting in the smallest reactor volume and maximum energy saving. Model predictions are consistent with experimental results. A selectivity-activity diagram is developed for guiding the development of stacked-bed catalyst systems.