Hydroprocessing Catalyst with Mixed Type I and II Active Sites

The patent divides the metal impregnation process into multiple sequential steps, with each step adding specific metal components (e.g., first impregnation with Mo and P, second impregnation with Ni and P). This segmentation allows precise control over metal distribution and phase formation, creating distinct Type I and Type II active sites that collectively enhance catalytic activity for hydrodenitrogenation and hydrodesulfurization.

The patent systematically varies impregnation parameters including solution concentration, impregnation time, drying temperature, and calcination conditions to optimize metal loading and phase distribution. By controlling these parameters, the process achieves high metals loading with improved catalytic performance while managing process complexity through methodical parameter optimization.

The patent performs multiple impregnation steps and controlled drying before final calcination, preparing the metal precursors in specific configurations that facilitate subsequent phase transformation. The preliminary impregnation steps establish metal distributions that, when calcined, produce the desired mix of Type I (highly crystalline) and Type II (less crystalline) active sites with optimal catalytic activity.

The patent employs controlled calcination at specific temperature ranges and durations to transform metal precursors into the desired oxide phases without excessive crystallization. By optimizing calcination parameters, the process maintains a balance between phase stability and catalytic activity, preserving the mixed Type I/Type II site structure that provides superior hydroprocessing performance.

The patent creates catalysts with spatially differentiated metal distributions through multiple impregnation steps. Type I active sites (highly crystalline metal oxides) and Type II active sites (less crystalline metal oxides) are distributed throughout the catalyst structure, with each type providing complementary catalytic functions. This local quality differentiation enables high overall activity while maintaining selectivity, as different site types can be optimized for different reaction pathways in hydrodenitrogenation and hydrodesulfurization.

The patent produces composite catalyst structures containing multiple metal components (Mo, Ni, P) in specific ratios and phases. The combination of different metal oxides creates synergistic effects where the composite structure provides both high catalytic activity and maintained selectivity. The mixed Type I/Type II site composition acts as a composite functional structure that balances productivity and product quality.