SSZ-92 Catalyst for Base Oil Dewaxing Yield
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Solution Overview
Problem
Current hydroisomerization catalytic dewaxing processes face challenges in producing base oils that meet product specifications while maintaining high yield, as they are prone to cracking and hydroisomerization reactions, leading to reduced base oil/lube yield and quality issues due to residual organic sulfur and nitrogen from upstream processes.
Innovation Solution
A molecular sieve belonging to the ZSM-48 family, specifically SSZ-92, with a silicon oxide to aluminum oxide mole ratio of 50 to 220, comprising at least 70% polytype 6 and an additional EUO-type phase, and incorporating magnesium, is used as a hydroisomerization catalyst to improve selectivity, lube yield, and viscosity index, reducing cracking and hydroisomerization reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydroisomerization catalysts are used for base oil production, then dewaxing capability is achieved, but cracking reactions increase leading to reduced base oil yield
Solution Approach 1:
The patent modifies the catalyst's chemical composition parameters by incorporating specific molecular sieves (ZSM-48 with SiO2/Al2O3 ratio of 80-150) and magnesium oxide (0.5-5 wt%), which changes the catalyst's acid site distribution and pore structure. This parameter modification suppresses cracking reactions while maintaining isomerization activity, directly resolving the contradiction between productivity and substance loss.
Solution Approach 2:
The invention creates a composite catalyst system combining ZSM-48 molecular sieve, magnesium oxide, and optionally hydro treating catalysts. This composite structure synergistically combines the shape-selective isomerization capability of ZSM-48 with the cracking suppression effect of magnesium oxide, achieving both high base oil yield and low cracking loss simultaneously.
2Reliability
If hydroisomerization reactions are promoted to improve base oil properties, then product quality increases, but undesired hydroisomerization reactions increase reducing yield
Solution Approach 1:
The patent creates local quality differentiation within the catalyst by incorporating magnesium oxide at specific locations and concentrations (0.5-5 wt%). The magnesium oxide modifies the local acid site environment, creating selective zones that promote desired isomerization while suppressing undesired hydroisomerization reactions. This local modification improves product quality without sacrificing yield.
Solution Approach 2:
By adjusting the SiO2/Al2O3 ratio of ZSM-48 to 80-150 and controlling magnesium oxide content, the patent optimizes the catalyst's pore size and acid strength parameters. These parameter changes create an optimal reaction environment that favors quality-improving isomerization reactions while minimizing yield-reducing hydroisomerization reactions.
3Ease of operation
If conventional catalysts are used for dewaxing, then processing capability is maintained, but residual sulfur and nitrogen affect product quality
Solution Approach 1:
The patent introduces magnesium oxide as an intermediary substance that mediates between the hydrocarbon feed and the catalyst's active sites. Magnesium oxide acts as a sulfur and nitrogen trap, preventing these impurities from poisoning the catalyst's active sites and affecting product quality, while maintaining full dewaxing capability.
Solution Approach 2:
The composite catalyst system combines ZSM-48 molecular sieve for dewaxing with magnesium oxide for impurity management. This composite structure maintains the dewaxing capability of ZSM-48 while adding the sulfur/nitrogen tolerance provided by magnesium oxide, thereby improving product quality without compromising operational capability.
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 SSZ-92 catalyst system enhances base oil/lube product properties by increasing selectivity, lube yield, and viscosity index, and reducing gas make, thereby improving the overall quality and yield of base oil/lube products.
Implementation Method 1
a catalyst comprising a molecular sieve belonging to the ZSM-48 family of zeolites... used as a hydroisomerization catalyst to improve selectivity, lube yield, and viscosity index
Implementation Method 2
Molecular sieve SSZ-92... a molecular sieve belonging to the ZSM-48 family of zeolites... having a morphology characterized as polycrystalline aggregates comprising crystallites collectively having an average aspect ratio of between 1 and 8
Data Source
AI summary
The present application pertains to family of new crystalline molecular sieves designated SSZ-92. Molecular sieve SSZ-92 is structurally similar to sieves falling within the ZSM-48 family of molecular sieves and is characterized as having magnesium.