Mesoporous Molecular Sieve Catalyst for Oil Isomerization
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Solution Overview
Problem
Current zeolite molecular sieves have insufficient mesopore surface area and silica-alumina ratio, leading to suboptimal catalytic properties when used as catalysts or catalyst supports.
Innovation Solution
A molecular sieve with a high silica-alumina ratio and increased mesopore volume is synthesized through a specific post-treatment step during crystallization, resulting in a catalyst with improved catalytic activity and longer lifespan due to enhanced mesopore surface area and dispersed active metal components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional zeolite molecular sieves are used as catalysts, then they provide high acidity and good stability, but they have insufficient mesopore surface area and suboptimal catalytic properties
Solution Approach 1:
The patent creates a hierarchical pore structure by combining micropores (from zeolite crystallites) with mesopores (formed during crystallization), resulting in a material that maintains the high acidity of conventional zeolites while adding mesopore pathways for improved reactant access and catalytic performance
Solution Approach 2:
The molecular sieve is synthesized as a composite structure with dual pore systems - microporous zeolite crystallites embedded in a mesoporous matrix, combining the advantages of both pore types to achieve high stability and enhanced mesopore surface area simultaneously
2Stability of the object's composition
If the silica-alumina ratio is increased to improve hydrothermal stability, then chemical stability improves, but mesopore surface area remains insufficient
Solution Approach 1:
The patent optimizes the silica-alumina ratio to greater than 20 and less than 40 (preferably 25-35) while controlling crystallization conditions to simultaneously achieve high hydrothermal stability and sufficient mesopore surface area, resolving the trade-off between stability and surface area
3Productivity
If molecular sieves with high isomerization degree are used, then isomerization reaction improves, but cracking reaction proportion increases and product yield decreases
Solution Approach 1:
The molecular sieve is divided into small crystallite sizes (0.5-5 μm) that fit within mesopores, creating segmented active sites distributed throughout the mesopore network. This segmentation allows reactants to access isomerization sites efficiently while preventing excessive cracking reactions, improving both isomerization degree and product yield
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 isomerization efficiency and reduced freezing point of feedstock oil, with increased mesopore surface area providing more reactive sites and highly dispersed active metals for enhanced catalytic performance.
Implementation Method 1
molecular sieve material typically has a high acidity and a high specific surface area
Implementation Method 2
paraffin hydrocarbons can undergo the isomerization reaction to some extent with these molecular sieve materials
Data Source
AI summary
A molecular sieve has a silica/alumina molar ratio of 100-300, and has a mesopore structure. One closed hysteresis loop appears in the range of P/P0=0.4-0.99 in the low temperature nitrogen gas adsorption-desorption curve, and the starting location of the closed hysteresis loop is in the range of P/P0=0.4-0.7. The catalyst formed from the molecular sieve as a solid acid not only has a good capacity of isomerization to reduce the freezing point, but also can produce a high yield of the product with a lower pour point. The process for preparing the catalyst involves steps including crystallization, filtration, calcination, and hydrothermal treatment.