Doped Zeolite Y Catalyst for Hydrocracking Selectivity
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Solution Overview
Problem
Conventional hydrocracking catalysts face challenges in achieving optimal balance between acid and hydrogenating functions, leading to suboptimal performance in producing middle distillates, with issues related to macropore content and selectivity, particularly in zeolite-based systems.
Innovation Solution
A doped hydrocracking catalyst is developed using a zeolite Y support with a specific lattice parameter and a silica-alumina matrix with reduced macropore content, incorporating elements like phosphorus, boron, or silicon to enhance catalytic performance in hydrocracking and hydrotreatment processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydrocracking catalysts use amorphous alumina-silica supports with high surface area, then catalyst activity is improved, but selectivity for middle distillates deteriorates due to macropore content
Solution Approach 1:
The patent applies porous materials by carefully controlling the pore size distribution of the alumina-silica support to eliminate macropores (>500 Å) while preserving mesopores and micropores. This selective pore structure maintains high surface area for catalyst activity while preventing the formation of unwanted light products, thereby improving selectivity for middle distillates without sacrificing productivity
Solution Approach 2:
The patent changes the textural parameters of the support by precisely controlling pore diameter distribution and total pore volume. By setting specific ranges for mean pore diameter (20-140 Å) and total pore volume (0.1-0.5 ml/g), the catalyst achieves optimal balance between activity and selectivity, resolving the contradiction between productivity and manufacturing precision
2Productivity
If zeolite content is increased to improve catalytic activity, then productivity is improved, but selectivity for light products increases which reduces middle distillate yield
Solution Approach 1:
The patent changes the pore size parameters of the zeolite-containing support to restrict pore diameters to 20-140 Å, eliminating macropores that lead to excessive cracking to light products. This parameter control allows higher zeolite content for improved activity while maintaining selectivity for middle distillates by preventing over-cracking
3Productivity
If catalyst packing density is increased to improve performance, then productivity is improved, but pore volume decreases which may affect mass transfer
Solution Approach 1:
The patent optimizes the balance between packing density and pore volume by setting specific ranges: packing density of 0.75-1.5 g/cm³ and total pore volume of 0.1-0.5 ml/g. This parameter optimization allows high catalyst performance through increased packing while maintaining sufficient pore volume for adequate mass transfer of reactants and products
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 exhibits improved catalytic activity and selectivity for middle distillates without compromising on the quality, achieving higher yields and stability through a synergistic effect between the zeolite, silica-alumina matrix, and the improved hydrogenating phase.
Implementation Method 1
incorporating elements like phosphorus, boron, or silicon to enhance catalytic performance
Implementation Method 2
The acid function is supplied by supports with surface areas generally of 150 to 800 m2/g and with a superficial acidity, such as halogenated aluminas (chlorinated or fluorinated), combinations of oxides of boron and aluminium, amorphous alumina-silicas and zeolites
Implementation Method 3
The hydrogenating function is supplied either by one or more metals from group VIII of the periodic table, or by a combination of at least one metal from group VIB of the periodic table and at least one group VIII metal
Data Source
AI summary
The present invention concerns doped catalysts on a mixed zeolite/alumino-silicate support with a low macropore content, and hydrocracking/hydroconversion and hydrotreatment processes employing them. The catalyst comprises at least one hydrodehydrogenating element selected from the group formed by elements from group VIB and group VIII of the periodic table and a doping element in a controlled quantity selected from phosphorus, boron and silicon, and a support based on zeolite Y defined by a lattice parameter a of the unit cell in the range 24.40×10−10 m to 24.15×10−10 m and silica-alumina containing a quantity of more than 5% by weight and 95% by weight or less of silica (SiO2).