Helicoidal Catalyst Asymmetry for Reactor Mixing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Commercial catalysts for gas/solid, liquid/solid, or gas/liquid/solid processes exhibit high void fraction percentages leading to low pressure drops, poor radial dispersion, and limited extraparticle material transfers due to their geometry, resulting in inefficient hydrodynamics and catalytic reactions.
Innovation Solution
The use of helicoidal catalysts with a void fraction percentage between 75% and 85% and a surface area/volume ratio greater than 1000 m2/m3, creating turbulence and enhancing mixing within reactors, thereby reducing pressure drops and improving radial dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional catalyst shapes (sphere, cylinder, hollow shapes) are used, then pressure drops are reduced due to high void fraction (>70%), but radial dispersion and extraparticle material transfers are poor
Solution Approach 1:
The patent applies asymmetry by using helicoidal catalyst shapes with asymmetric geometries (number of lobes or blades not equal to a simple symmetric pattern) instead of traditional symmetric shapes like spheres or cylinders. This asymmetric helicoidal structure disrupts symmetric flow patterns, creates turbulence, and improves radial dispersion while maintaining acceptable pressure drops, thereby resolving the contradiction between energy loss and material transfer efficiency
2Ease of manufacture
If hollow shapes with symmetric channels are used, then manufacturing is simplified, but packing creates numerous preferential pathways leading to low radial dispersion and poor mixing
Solution Approach 1:
The patent replaces symmetric channel patterns with asymmetric helicoidal structures that have non-uniform flow paths. The asymmetric geometry eliminates preferential pathways by ensuring that fluid must traverse varied routes around each catalyst element, thereby improving radial dispersion uniformity while the helicoidal structure itself provides a manufacturable form through consistent geometric replication
Solution Approach 2:
The patent employs curved helicoidal surfaces instead of straight or planar channel structures. The curved geometry of the helicoidal catalysts creates continuous flow direction changes and turbulence, eliminating the straight preferential pathways found in traditional hollow shapes with linear channels, thus improving mixing and radial dispersion while maintaining ease of manufacture through standardized curved geometries
3Ease of operation
If traditional catalyst shapes are used, then packing is simple, but fluid slides over shapes without generating turbulence or mixing
Solution Approach 1:
The patent uses asymmetric helicoidal catalyst shapes that inherently generate turbulence as fluid flows around them. The asymmetric geometry creates uneven flow distribution and vortex formation, significantly increasing mixing speed compared to traditional symmetric shapes where fluid simply slides over smooth surfaces. The packing remains simple as the helicoidal elements are uniform and can be randomly packed like traditional catalysts
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 helicoidal catalysts significantly reduce pressure drops and enhance radial dispersion, leading to improved catalytic reaction efficiency by promoting better mixing and material transfer, with axial dispersions lower than traditional shapes, resulting in operation closer to plug-flow reactors.
Implementation Method 1
Each helicoid according to the invention creates turbulences and the use of a packing of helicoids according to the invention leads to phenomena of ejection of gas from one helicoid to another locally improving the mixing within catalytic reactors.
Data Source
AI summary
A catalyst for catalytic reactors of which the outer shape is a helix with n blades, where n is greater than or equal to 1, wherein the stack void fraction percentage is between 75% and 85% and the surface area/volume ratio is greater than 1000 square meters/square meters.