Honeycomb Catalyst Pore Geometry for Gas Flow and Loading
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Solution Overview
Problem
Honeycomb catalyst bodies face issues where the catalyst loaded onto the inner surfaces of pores does not effectively function due to pores being closed or their open frontal areas being narrowed, preventing exhaust gas flow and subsequent catalyst contact.
Innovation Solution
A honeycomb structure with a design where 20-100% of pores have a substantially circular or elliptic shape, maintaining 50-70% porosity and 10-50 μm average pore diameter, ensuring a large ratio of pores are open on the surface with narrowed centers, allowing for efficient catalyst loading and gas flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the catalyst is loaded onto the inner wall surfaces of the pores to increase the amount of catalyst, then the catalyst loading amount is improved, but the pores are closed or their open frontal areas are narrowed, preventing exhaust gas flow and catalyst contact
Solution Approach 1:
The patent applies local quality by creating pores with non-uniform cross-sections along their length. The pores have larger open frontal areas at their openings and smaller cross-sectional areas in their central regions. This local variation in pore geometry allows the catalyst to be loaded on the inner wall surfaces effectively while maintaining sufficient open frontal areas for exhaust gas flow, thus resolving the contradiction between increasing catalyst loading and ensuring gas-catalyst contact.
2Reliability
If the pores are made with larger open frontal areas to ensure gas flow, then the exhaust gas contact with catalyst is improved, but the structural strength of partition walls is reduced
Solution Approach 1:
The patent applies local quality by creating pores with non-uniform cross-sections along their length. The pores have larger open frontal areas at their openings and smaller cross-sectional areas in their central regions. This local variation in pore geometry allows the catalyst to be loaded on the inner wall surfaces effectively while maintaining sufficient open frontal areas for exhaust gas flow, thus resolving the contradiction between increasing catalyst loading and ensuring gas-catalyst contact.
3Ease of manufacture
If the pores have uniform cross-sections to simplify manufacturing, then the manufacturing process is improved, but the catalyst loading efficiency and gas flow are compromised
Solution Approach 1:
The patent applies local quality by creating pores with non-uniform cross-sections along their length. The pores have larger open frontal areas at their openings and smaller cross-sectional areas in their central regions. This local variation in pore geometry allows the catalyst to be loaded on the inner wall surfaces effectively while maintaining sufficient open frontal areas for exhaust gas flow, thus resolving the contradiction between increasing catalyst loading and ensuring gas-catalyst contact.
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 design enables a high loading of catalyst while maintaining structural strength, ensuring effective catalyst action and preventing catalyst peeling, even with bulky metal-substituted zeolite, by maintaining a high porosity and suitable pore distribution.
Implementation Method 1
a honeycomb structure is formed by porous partition walls having numerous pores
Data Source
AI summary
[Problems] There is disclosed a technology which can load a large amount of catalyst, and enables the loaded catalyst to effectively exert a catalyst action. [Means for Solving the Problems] A honeycomb structure including porous partition walls 5 with which a plurality of cells 4 are formed, a porosity of the partition walls 5 is from 45 to 70%, and when pores 10 having the maximum width in excess of 10 µm in a cross section of each of the partition walls 5 which is parallel to a thickness direction Y of the partition wall are large pores 12 and the partition wall 5 is equally divided into three regions of a center region and surface layer regions present on both sides of the center region along the thickness direction Y, in the cross section of the partition wall 5 which is parallel to the thickness direction Y, a total area of cross sections of the large pores 12 which appear in the cross sections of the surface layer regions is from 60 to 100% of a total area of cross sections of all the pores 10 which appear in the cross sections of the surface layer regions, and a total area of cross sections of the large pores 12 which appear in the cross section of the center region is from 0 to 40% of the total area of cross sections of all the pores 10 which appear in the cross section of the center region.