Hydrocracking Catalyst Pore Volume via Composite Support

The patent uses a composite support structure combining molecular sieve (zeolite) with metal sulfides and alumina. This composite material integrates the stability of molecular sieve with the porous structure of alumina, creating a support that provides both structural stability and adequate pore volume for reactant accessibility. The composite nature allows synergistic effects where each component contributes its advantageous properties.

The patent employs porous alumina as a key component of the support structure. The alumina provides a porous matrix with controlled pore size distribution that enhances the accessibility of reactant molecules to active sites. The porous structure of alumina complements the molecular sieve structure, creating a hierarchical pore system that facilitates mass transport while maintaining catalytic activity.

The patent creates different pore size regions within the catalyst structure. The alumina component provides larger pores for bulk mass transport and accessibility, while the molecular sieve provides smaller, uniform pores for selective catalysis. This local differentiation of pore sizes allows the catalyst to simultaneously achieve good accessibility and maintain structural integrity through the hierarchical pore architecture.

The catalyst structure implements a nested pore system where the molecular sieve units are embedded within the alumina matrix. This nested arrangement creates a hierarchical pore structure where larger alumina pores provide access to smaller molecular sieve pores, enabling reactants to reach active sites while the outer structure maintains mechanical strength and stability.