Dewaxing Catalyst System with Zeolite Concentration Gradient
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Solution Overview
Problem
Current catalyst systems for dewaxing hydrocarbon feedstocks face challenges in achieving enhanced activity and selectivity while maintaining economic viability, with existing solutions often resulting in undesirable gas yields and high material costs.
Innovation Solution
A catalyst system comprising a graduated mixture of ZSM-12 and EU-2/ZSM-48 zeolite based catalysts within a single catalyst bed, with a concentration gradient that decreases ZSM-12 and increases EU-2/ZSM-48 zeolite concentrations from inlet to outlet, enhancing catalytic performance and base oil yields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the zeolite content of catalysts is increased to arrive at increased activity, then catalytic activity is improved, but material costs increase
Solution Approach 1:
The patent applies local quality by creating a catalyst bed with non-uniform zeolite distribution. The concentration of ZSM-12 and EU-2/ZSM-48 zeolites varies through the bed depth, with higher ZSM-12 concentration at the inlet and higher EU-2/ZSM-48 concentration at the outlet. This gradient structure optimizes catalytic activity at different stages of the reaction while using zeolite materials more efficiently, avoiding the need to uniformly increase zeolite content throughout the entire bed.
Solution Approach 2:
The patent changes the concentration parameter of zeolite components through the catalyst bed. By varying the concentration of different zeolite types (ZSM-12 and EU-2/ZSM-48) at different positions in the bed, the system achieves optimized catalytic performance. The concentration gradient allows different zeolite types to operate in their optimal concentration ranges at different locations, improving overall activity without proportionally increasing total material costs.
2Productivity
If a dual catalyst cascade process is used with ZSM-12 and ZSM-5, then dewaxing performance is improved, but gas make increases significantly
Solution Approach 1:
The patent changes the zeolite type parameter in the catalyst composition, replacing ZSM-5 with EU-2/ZSM-48 in the second catalyst bed. This parameter change maintains the dual-catalyst cascade structure's dewaxing performance while significantly reducing unwanted gas formation. The EU-2/ZSM-48 zeolite has different pore structure and catalytic properties that favor liquid product formation over gas formation compared to ZSM-5.
Solution Approach 2:
The patent uses a composite catalyst system combining ZSM-12 and EU-2/ZSM-48 zeolites in a specific configuration. The composite structure leverages the complementary properties of both zeolite types: ZSM-12 provides initial hydroisomerization activity while EU-2/ZSM-48 provides selective dewaxing activity with reduced gas formation. This composite approach achieves the desired dewaxing performance without the excessive gas make associated with ZSM-5 based systems.
3Productivity
If a stacked catalyst system with ZSM-12 on top and EU-2 on bottom is used, then base oil yield is improved, but system complexity increases
Solution Approach 1:
The patent merges the functionality of separate stacked catalyst beds into a single integrated catalyst bed. Instead of requiring two separate beds with ZSM-12 on top and EU-2 on bottom, the invention combines both zeolite types within one bed with a concentration gradient. This merging maintains the beneficial base oil yield enhancement while simplifying the system structure, reducing the number of components, and eliminating the need for complex stacked bed configuration.
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 graduated catalyst system achieves improved catalytic activity and base oil yields compared to systems using only ZSM-12 or EU-2/ZSM-48 catalysts, with higher base oil yields and comparable activity to stacked bed systems, while maintaining economic attractiveness.
Implementation Method 1
catalyst system for dewaxing of a hydrocarbon feedstock comprising a ZSM-12 zeolite based catalyst and a EU-2 and/or ZSM-48 zeolite based catalyst
Data Source
AI summary
A catalyst system for dewaxing of a hydrocarbon feedstock comprising a mixture of a first dewaxing catalyst composition and a second dewaxing catalyst composition, wherein the first dewaxing catalyst composition is a ZSM-12 zeolite based catalyst composition and the second dewaxing catalyst composition is a EU-2 and/or ZSM-48 zeolite based catalyst composition, and wherein a concentration gradient of the mixture is achieved within a single catalyst bed, such that the concentration of the first dewaxing catalyst is decreasing and the concentration of the second dewaxing catalyst is increasing through the catalyst bed; and a process for dewaxing of a hydrocarbon feedstock comprising contacting the hydrocarbon feedstock with said catalyst system.