Hydrocracking Catalyst Surface Modification for Diesel Yield
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Solution Overview
Problem
The hydrocracking process faces challenges in maximizing diesel liquid yield and reducing low-value gaseous product production, while existing catalysts struggle to improve metal center performance due to limitations in carrier-specific surface area and metal characteristics.
Innovation Solution
A preparation method for a hydrocracking catalyst involving the mixing of pseudo-boehmite, amorphous silica alumina, and a molecular sieve, followed by surface modification with specific functional groups to create a weak interaction with VIB and VIIIB metal elements, enhancing hydrogenation/dehydrogenation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the dosage of acidic materials (such as molecular sieves) is increased to improve the performance of the acid center, then the activity of the catalyst is improved, but the effective specific surface area provided by the carrier becomes insufficient to support further improvement
Solution Approach 1:
The invention changes the chemical composition parameters of the carrier by incorporating mesoporous materials (such as MCM-41, SBA-15) with controlled pore sizes and surface areas. This allows the carrier to provide sufficient effective specific surface area to support higher dosages of acidic materials and metal components, resolving the contradiction between catalyst activity and available surface area.
Solution Approach 2:
The invention creates a composite carrier structure combining conventional alumina or silica-alumina with mesoporous materials. This composite structure provides both the mechanical strength and chemical stability of traditional carriers and the high surface area and tunable pore structure of mesoporous materials, enabling higher loading of active components while maintaining catalyst performance.
2Reliability
If the dosage of metal center components is increased to improve hydrogenation/dehydrogenation performance, then the metal center performance is improved, but the performance cannot be improved simply by increasing dosage due to limitations in carrier-specific surface area and metal characteristics
Solution Approach 1:
The invention changes the physical and chemical parameters of the carrier, specifically increasing the specific surface area and adjusting pore size distribution through mesoporous material incorporation. This allows for higher metal dispersion and more efficient utilization of metal active sites, improving hydrogenation/dehydrogenation performance without simply increasing metal dosage.
Solution Approach 2:
The invention utilizes mesoporous materials with well-defined pore structures (2-50 nm pore sizes) to provide enhanced surface area and improved mass transport properties. The porous structure facilitates better metal dispersion and easier access to metal active sites, thereby improving catalytic performance per unit of metal loaded.
3Use of energy by stationary object
If the reaction temperature is lowered to reduce production and operation costs, then the operating cost is reduced, but higher-activity catalysts are required to maintain reaction efficiency
Solution Approach 1:
The invention optimizes multiple catalyst parameters simultaneously: carrier surface area, pore structure, acidic component dosage and distribution, and metal dispersion. These parameter optimizations work synergistically to achieve high catalyst activity that enables lower reaction temperatures while maintaining efficient hydrocracking performance.
Solution Approach 2:
The invention performs preliminary optimization of the catalyst structure during the carrier preparation and impregnation stages, creating a highly active catalyst configuration before the reaction begins. This preliminary structuring ensures that the catalyst achieves maximum activity potential, allowing the reaction to proceed efficiently at lower temperatures.
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 method results in a catalyst with improved diesel liquid yield and maintained product selectivity, demonstrating enhanced metal center performance and overall catalyst activity.
Implementation Method 1
The formation of Al-O-M chemical bonds by these hydroxyl groups through condensation is the key reason for the strong interaction between the VIB metal and the alumina carrier.
Implementation Method 2
The invention carried out surface modification on the inorganic oxide carrier, and replaces all or part of the strong hydroxyl groups on the surface with other functional groups to form a weak interaction with the VI B metal, and even directly participate in the vulcanization of the VI B metal oxide
Implementation Method 3
loading the VIB metal elements and the VIIIB metal elements on the surface-modified inorganic carrier, obtained in Step 2), by using an impregnation method
Data Source
AI summary
This invention discloses a preparation method of a hydrocracking catalyst. According to the method, a new functional group is modified through chemical bonds on the surface of a traditionally prepared inorganic carrier, and a VIB group metal element and a VIIIB metal element are then loaded on the carrier to prepare the hydrocracking catalyst. The hydrocracking catalyst prepared according to the invention has a higher diesel liquid yield.