Six-Lobe Star Ceramic Catalyst Support for Surface Area and Pressure Drop
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Solution Overview
Problem
Existing star-shaped alumina extrudates face challenges in achieving a high geometric surface area while minimizing pressure drop and ensuring mechanical stability, particularly in fixed bed processes.
Innovation Solution
A six-lobe star-shaped ceramic body with specific geometric ratios and mirror symmetry is developed, combining high geometric surface area with low pressure drop and high mechanical strength, optimized for use as a catalyst support or reactor filling material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If star-shaped extrudates are used to minimize pressure drop, then pressure drop is reduced, but geometric surface area decreases
Solution Approach 1:
The patent transitions from traditional 2D surface area optimization to 3D geometric optimization by introducing a star-shaped cross-section with multiple lobes. This dimensional change allows the extrudate to achieve both low pressure drop (through streamlined shape) and high geometric surface area (through lobe extensions) simultaneously, resolving the contradiction between these two parameters.
Solution Approach 2:
The extrudate cross-section is segmented into multiple lobes (typically 3-6 lobes) radiating from a central core. This segmentation creates multiple surface-exposed regions that increase the overall geometric surface area while maintaining the star-shaped profile that minimizes pressure drop during fluid flow through the fixed bed.
2Productivity
If high geometric surface area is achieved, then catalytic activity is improved, but mechanical strength decreases
Solution Approach 1:
The patent applies local quality by optimizing different regions of the extrudate for different functions: the central core provides mechanical strength and structural integrity, while the lobes provide high geometric surface area for catalytic activity. This spatial differentiation of properties allows simultaneous achievement of high catalytic activity and adequate mechanical strength.
Solution Approach 2:
The extrudate employs composite material structure combining a ceramic matrix (providing mechanical strength) with a high-surface-area morphology (providing catalytic activity). The composite nature of the material system allows the mechanical and catalytic properties to be optimized independently through material composition and geometric design.
3Strength
If traditional tablet or extrudate shapes are used, then mechanical strength is maintained, but pressure drop increases
Solution Approach 1:
The patent employs curved, rounded lobe shapes in the star-shaped cross-section rather than sharp corners or flat surfaces. This spheroidality reduces flow separation and turbulence in the fixed bed, minimizing pressure drop while maintaining mechanical strength through the rounded stress distribution in the ceramic structure.
Data Source
AI summary
Star-shaped ceramic body, wherein the cross-section of the body has six lobes, the ratio of the maximum radius r2 in the star to radius r1 of a circle connecting the intersections of the lobes being in the range from 1.0 to 3.61, preferably from 2.17 to 3.61, the ratio of the area F1 inside this circle to the summed area F2 of the lobes outside this circle being in the range of from 0.54 to 0.90, the ratio of the distance x2 between the two intersections I of one lobe with neighboring lobes and the radius r1 of the circle being in the range of from 0.67 to 1.11. The ceramic body is used as catalyst-support.