Regeneration of CoMo Sulfide Exhaustive Hydrofining Catalysts Using Organic Reagents

Commercial cobalt-molybdenum catalyst after use for two years for diesel fraction hydrofining was oxidatively regenerated and activated with organic acids (citric and thioglycolic), ethylene glycol, and combined solution. It is shown that the main reasons for the loss of activity of the studied catalyst during its use are coke deposition on the catalyst surface and change in the properties of the applied active phase, which intensify in the oxidative regeneration process. Treatment of the oxidatively regenerated catalyst with solution of the studied reagents can fully restore the activity in the reaction of hydrodesulfurization of dibenzothiophene, and in the case where combined citric acid and ethylene glycol solution is used the observed hydrodesulfurization reaction rate constant exceeds the value obtained on fresh catalyst.