Zeolite Catalyst Segmentation for Propylene Yield Control
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Solution Overview
Problem
Current methods for producing propylene and aromatic hydrocarbons from hydrocarbon feedstocks face challenges such as limited yield flexibility, catalyst degradation due to coking and regeneration issues, and the need for complex and costly reaction systems, particularly when using zeolite catalysts.
Innovation Solution
A process involving separate production steps for propylene and aromatic hydrocarbons using specific zeolite catalysts with controlled pore diameters, metal content, and SiO2/Al2O3 ratios, allowing for recycling of C4+ hydrocarbons to optimize yield ratios and reduce diolefin compound impact, thereby stabilizing catalyst activity and simplifying equipment requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If thermal cracking is used to obtain propylene and aromatic hydrocarbons from hydrocarbon feedstock, then the production process is simple, but the product yields are limited and the yield structure is not flexible
Solution Approach 1:
The patent divides the production process into two separate steps: (1) propylene production step using a first zeolite-containing catalyst, and (2) aromatic hydrocarbon production step using a second zeolite-containing catalyst. This segmentation allows independent optimization of each step's yield structure, enabling flexible control over final product yields while maintaining operational simplicity through standardized catalyst modules.
2Productivity
If zeolite catalysts are used for catalytic conversion to improve propylene yield, then propylene yield is improved, but coke accumulates on the catalyst and must be frequently removed by combustion, causing permanent degradation of catalyst activity
Solution Approach 1:
The patent specifies precise zeolite parameters including pore diameter (5-6.5×10⁻¹⁰ m), SiO2/Al2O3 ratio (80-200), and metal content (0.01-5% by mass) to optimize catalytic activity while minimizing coking. These parameter changes enable high propylene yield while reducing coke formation rate, extending catalyst life between regenerations and maintaining activity stability.
Solution Approach 2:
The patent accepts that zeolite catalysts will eventually degrade and need replacement, designing the system for efficient regeneration cycles. The catalysts are optimized to provide maximum productivity during their operational life, and the process includes provisions for catalyst regeneration and replacement without requiring complex recovery systems.
3Reliability
If proton-free zeolite catalyst is used to convert hydrocarbon feedstock into ethylene, propylene and monocyclic aromatic hydrocarbons, then the catalyst is resistant to regeneration degradation, but it is still vulnerable to coking deterioration and requires a large amount of heat supply
Solution Approach 1:
The patent uses composite zeolite materials containing specific metal components (Group IB metals like Ag, Cu, or Au) dispersed on the zeolite support. This composite structure provides regeneration resistance from the zeolite framework while the metal components promote dehydrogenation reactions that reduce coking. The composite material achieves both goals simultaneously.
4Productivity
If catalytic conversion is used to produce propylene from hydrocarbon feedstock containing olefins, then propylene can be obtained, but the catalyst activity and contact time must be strictly controlled to prevent propylene conversion to aromatic hydrocarbons
Solution Approach 1:
The patent separates propylene production and aromatic hydrocarbon production into two distinct steps using different catalysts. The first catalyst (with specific pore size and metal content) is optimized for propylene production with controlled activity to minimize further conversion. The second catalyst handles aromatic hydrocarbon production. This segmentation simplifies operation by eliminating the need for strict real-time control of contact time and activity balance.
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
This approach enables efficient and stable production of propylene and aromatic hydrocarbons with flexible yield ratios, reducing catalyst deterioration and equipment complexity, and improving operational stability.
Implementation Method 1
catalytic conversion and catalytic cyclization from a hydrocarbon feedstock
Implementation Method 2
thermal cracking has been widely used for obtaining propylene and aromatic hydrocarbons from hydrocarbon feedstock
Data Source
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AI summary
It is an object of the present invention to provide an improved process whereby the yield structure of the components can be varied by a simple method, and the products can be produced stably and efficiently in a process for producing propylene and aromatic hydrocarbons from a hydrocarbon feedstock containing C4-12 olefins using a medium pore diameter zeolite-containing catalyst. A process for producing is disclosed which comprises a propylene production step wherein a specific zeolite catalyst is used to remove a C4+ hydrocarbon component from a reaction mixture, and part of the hydrocarbon component is recycled as necessary without modification, and an aromatic hydrocarbon production step wherein all or a part of the C4+ hydrocarbon component is used as the raw material.