Modified Beta Zeolite Catalyst for C4 Olefin Selectivity
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Solution Overview
Problem
Current catalytic cracking catalysts fail to significantly increase the concentration of C4 olefins in liquefied gas while maintaining gasoline yield, due to poor selectivity and stability issues with β zeolites, particularly in the cracking of heavy oils.
Innovation Solution
A modified β zeolite with 0.5-15 wt% IVB group metal elements, optimized acid distribution, and a catalytic cracking catalyst composition including Y-type zeolite, modified β zeolite, clay, and heat-resistant inorganic oxide, which enhances C4 olefin selectivity and yield through controlled acid center ratios and calcination processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If β zeolite is used in catalytic cracking catalyst, then C4 olefin selectivity is improved, but structure stability deteriorates due to easy structural damage during templating agent removal and dealumination in reaction process
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of β zeolite through phosphorus incorporation and dealumination treatment. The SiO2/Al2O3 ratio is increased to 50-150, and phosphorus content is controlled at 0.1-5 wt% as P2O5. These parameter changes enhance structure stability while maintaining C4 olefin selectivity by optimizing the zeolite's chemical environment.
Solution Approach 2:
The patent creates a composite material system by incorporating phosphorus into the β zeolite framework and combining it with other catalyst components (Y-type zeolite 10-50 wt%, clay 20-60 wt%, inorganic oxide 10-40 wt%). This composite approach synergistically improves both selectivity and stability, as phosphorus acts as a structural promoter while the multi-component catalyst system balances various catalytic functions.
2Reliability
If phosphorus content is increased to protect framework aluminum, then hydrothermal stability is improved, but manufacturing complexity increases due to precise control requirements
Solution Approach 1:
The patent defines specific parameter ranges to balance stability and manufacturability: phosphorus content at 0.1-5 wt% as P2O5 and SiO2/Al2O3 ratio at 50-150. These quantified parameters provide clear manufacturing targets while ensuring hydrothermal stability, making the process controllable and reproducible without excessive complexity.
3Manufacturing precision
If dealumination treatment is applied to increase silica-alumina ratio, then C4 olefin selectivity is improved, but acid site density decreases
Solution Approach 1:
The patent optimizes the SiO2/Al2O3 ratio to 50-150 through controlled dealumination, which enhances C4 olefin selectivity by creating a more selective pore environment. Simultaneously, phosphorus is introduced at 0.1-5 wt% to compensate for acid site loss, maintaining sufficient catalytic activity while achieving the desired selectivity improvement.
Solution Approach 2:
The patent creates a composite catalyst system combining dealuminized β zeolite with phosphorus, Y-type zeolite, clay, and inorganic oxide. This composite approach compensates for reduced acid site density in the dealuminized component by incorporating other active components, thereby maintaining overall productivity while achieving high C4 olefin 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 modified β zeolite and catalyst composition improve C4 olefin concentration and selectivity in liquefied gas without reducing gasoline yield, demonstrating enhanced catalytic performance and stability in heavy oil cracking.
Implementation Method 1
a modified β zeolite, comprising 0.5-15 wt % of an IVB group metal element in terms of oxide on a dry basis weight of the modified β zeolite. The number of medium strong acid centers of the modified β zeolite accounts for 30-60% of the total acid amount, the number of strong acid centers accounts for 5-25% of the total acid amount
Implementation Method 2
a first calcination at 350-650° C. for 0.5-5 hr
Data Source
AI summary
A modified β zeolite has 0.5-15 wt % of an IVB group metal element in terms of oxide on the dry basis weight of the modified β zeolite. The number of medium strong acid centers of the modified β zeolite accounts for 30-60% of the total acid amount, the number of strong acid centers accounts for 5-25% of the total acid amount, and the ratio of B acid to L acid is 0.8 or more. The ratio of the weight content of the IVB group metal element in the modified β zeolite body phase to the weight content of the IVB group metal element on the surface is 0.1-0.8. The catalytic cracking catalyst containing the modified β zeolite has good selectivity and yield of C4 olefin.