Cylindrical Catalyst with Domed Ends and Flutes
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Solution Overview
Problem
Existing shaped heterogeneous catalysts face challenges in balancing high surface area and throughput due to pressure drop issues in packed beds, where flutes or channels may not effectively translate to increased geometric surface area when packed.
Innovation Solution
A cylindrical catalyst unit with domed ends and multiple flutes along its length, where the aspect ratio and dome-to-cylinder ratio are optimized to enhance effective geometric surface area and reduce pressure drop, fabricated using a pelleting process with specific dimensions and features to prevent interlocking and attrition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If smaller catalyst particles are used to increase surface area and activity, then catalytic activity is improved, but pressure drop through the catalyst bed increases and throughput decreases
Solution Approach 1:
The catalyst units feature domed ends instead of flat surfaces, creating a more spherical overall shape. This curvature allows units to nestle together more efficiently in the packed bed, reducing voidage and improving contact between units while maintaining lower pressure drop across the bed.
Solution Approach 2:
The invention adds dimensional complexity by incorporating flutes (channels) running along the length of the cylindrical catalyst units. These flutes increase the geometric surface area available for catalysis without significantly increasing the overall unit size, thereby maintaining low pressure drop while enhancing activity.
2Area of moving object
If flutes or channels are added to catalyst design to increase geometric surface area, then theoretical surface area is improved, but effective geometric surface area is reduced by packing effects
Solution Approach 1:
The domed ends create a more compact, spherical shape that packs more efficiently in the reactor bed. This reduces the voidage between particles and ensures that the flutes remain accessible to reactants, maintaining their effectiveness for catalysis despite the dense packing arrangement.
3Productivity
If aspect ratio is increased to improve throughput, then pressure drop is reduced, but catalytic activity decreases due to lower surface area
Solution Approach 1:
The flutes add surface area in a dimensional sense without increasing the overall unit size. By creating channels along the length of the cylinder, the design provides additional catalytic surface area that doesn't increase the aspect ratio, thereby maintaining both throughput and activity.
4Area of moving object
If domed ends are added to catalyst unit, then effective geometric surface area and voidage relationship is improved, but manufacturing complexity increases
Solution Approach 1:
The domed ends are formed by the curvature of the extrusion die, which naturally creates the rounded shape during the extrusion process. This approach incorporates the domed geometry without requiring additional machining or forming steps, thereby maintaining manufacturing simplicity while achieving the desired shape benefits.
Data Source
Figure 1~3
AI summary
A catalyst unit is described in the form of a cylinder having a length C and diameter D, which has two or more flutes running along its length, wherein said cylinder has domed ends of lengths A and B, such that (A+B+C)/D is in the range 0.50 to 2.00, and (A+B)/C is in the range 0.40 to 5.00. The catalyst may be used particularly in reactions where hydrogen is a reactant such as hydroprocessing, hydrogenation, water-gas shift reactions, methanation, hydrocarbon synthesis by the Fischer-Tropsch reaction, methanol synthesis and ammonia synthesis.