Modified Zeolite Catalyst for Hydrocracking Selectivity
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Solution Overview
Problem
Conventional hydrocracking processes face challenges in achieving high activity and selectivity for middle distillate production, with catalysts based on amorphous supports being inactive and those with zeolites having lower selectivity due to imbalanced acid and hydrogenating functions.
Innovation Solution
A catalyst comprising a sulphide phase with a hydro-dehydrogenating element from group VIB and group VIII, combined with a modified zeolite that has been treated with alkaline cations, silicon-containing compounds, and undergoes partial cation exchange and heat treatment, optimizing the alkaline cation to aluminum ratio for enhanced activity and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If zeolite-based catalysts are used to increase catalytic activity, then activity is improved, but selectivity in middle distillates deteriorates
Solution Approach 1:
The patent modifies the zeolite structure by controlling the Si/Al ratio and introducing specific cations (Na+, K+, Cs+) to adjust the strength and distribution of acid sites. This parameter optimization allows the catalyst to maintain high activity while improving selectivity for middle distillates by reducing excessive cracking reactions
Solution Approach 2:
The patent combines modified zeolite with metal sulfide phases (CoMo, NiMo, WS2, MoS2) to create a bifunctional catalyst. The zeolite provides shape-selective acid catalysis for high activity, while the metal sulfide phase provides hydrogenation function to control product distribution and improve middle distillate selectivity
2Manufacturing precision
If amorphous support catalysts are used, then selectivity in middle distillates is improved, but activity deteriorates
Solution Approach 1:
The patent utilizes the porous structure of zeolite with controlled pore size and shape to provide shape-selective catalysis. The ordered microporous structure allows selective diffusion of reactants and products, maintaining high selectivity for middle distillates while the high surface area and acid site density provide high catalytic activity
3Productivity
If strong acid function is increased to improve activity, then activity is improved, but selectivity in middle distillates deteriorates
Solution Approach 1:
The patent optimizes the acid function by precisely controlling the Si/Al ratio in the zeolite framework and introducing alkaline cations to neutralize excessive strong acid sites. This creates a balanced acid function that provides sufficient activity while preventing over-cracking that would reduce middle distillate selectivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The catalyst achieves higher conversion levels and middle distillate yields while minimizing naphtha production, offering improved activity and selectivity in hydrocracking processes.
Implementation Method 1
a step of introducing at least one alkaline cation belonging to groups IA or IIA of the periodic table
Implementation Method 2
a step of treating said zeolite in the presence of at least one molecular compound containing at least one silicon atom
Implementation Method 3
The hydrocracking of heavy oil cuts is a very important refining process which makes it possible to produce, from excess heavy feedstocks with little recovery, lighter fractions
Data Source
AI summary
The invention relates to a method for the hydrocracking and/or hydroprocessing of hydrocarbon feeds, using a catalyst comprising at least one hydro-dehydrogenating metal selected from the group containing metals from group VIB and non-noble group VIII of the periodic table, and a substrate comprising at least one zeolite which has at least pore openings containing 12 oxygen atoms and which is modified by: (a) at least one step comprising the introduction of at least one alkaline cation belonging to groups IA or IIA of the periodic table; (b) a step comprising the treatment of the zeolite in the presence of at least one molecular compound containing at least one silicon atom; (c) at least one step comprising the partial exchange of the above-mentioned alkaline cations with NH4 + cations, such that the remaining concentration of alkaline cations in the modified zeolite at the end of step (c) is such that the alkaline cation/aluminium molar ratio is between 0.2:1 and 0:01:1; and (d) at least one heat treatment step.