Catalyst Honeycomb with Optimized Particle Size
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Solution Overview
Problem
The existing catalyst supporting honeycombs have a large diameter of supported catalyst particles compared to soot aggregate particles, resulting in few contact points and inefficient soot combustion by active oxygen, leading to soot accumulation and frequent forced regeneration, which lowers fuel economy.
Innovation Solution
The catalyst supporting honeycomb design features a pillar-shaped structure with a larger cross-sectional area of large-volume cells compared to small-volume cells, with oxide catalyst particles of 0.05 to 1.00 µm diameter, enhancing contact points between soot and catalyst, and using materials like silicon carbide for heat resistance and mechanical strength, along with specific oxide catalysts for improved active oxygen delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the honeycomb structured body is impregnated in the catalyst solution in a slurry state, then the catalyst can be supported on the honeycomb, but the diameter of the supported catalyst particles becomes much larger than the diameter of soot aggregate particles, resulting in few contact points between catalyst and soot
Solution Approach 1:
The patent applies parameter changes by controlling the catalyst particle diameter to be within a specific range (0.05 to 1.00 μm, preferably 0.1 to 0.5 μm) to match the soot aggregate particle size. This size optimization increases the number of contact points between catalyst and soot particles, thereby improving soot combustion efficiency without requiring slurry impregnation
Solution Approach 2:
The patent uses a small amount of binder (0.1 to 5 mass% relative to catalyst) to achieve adequate adhesion without excessive binding that would block active sites. This partial action approach ensures sufficient catalyst support while maintaining high soot combustion activity
2Ease of manufacture
If the catalyst particles are large in diameter, then the catalyst can be easily supported on the honeycomb, but the contact points between catalyst particles and soot aggregate particles are few, reducing soot combustion behavior
Solution Approach 1:
The patent optimizes catalyst particle size parameters to fall within 0.05 to 1.00 μm (preferably 0.1 to 0.5 μm), which balances ease of support on the honeycomb structure with sufficient contact surface area for soot combustion. This parameter optimization ensures both manufacturability and high soot combustion productivity
Solution Approach 2:
The patent performs preliminary size selection and control of catalyst particles before support, ensuring they fall within the optimal diameter range. This preliminary action prevents the formation of oversized particles that would reduce contact points, while maintaining ease of support through controlled particle characteristics
3Quantity of substance
If soot accumulates on cell walls, then the catalyst supporting honeycomb captures soot, but forced regeneration using high temperature exhaust gases is required frequently, lowering fuel economy
Solution Approach 1:
The patent changes the catalyst particle diameter parameter to 0.05 to 1.00 μm (preferably 0.1 to 0.5 μm), which increases contact points with soot particles and enhances soot combustion efficiency. This parameter optimization reduces soot accumulation on cell walls and decreases the frequency of forced regeneration, thereby improving fuel economy
Solution Approach 2:
The patent employs readily available oxide catalysts (such as cerium oxide, zirconium oxide, or their mixed oxides) with optimized particle sizes that provide effective soot combustion without requiring expensive complex structures. This approach maintains fuel economy by reducing the need for frequent high-temperature regeneration operations
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 improves soot combustion efficiency, reduces soot accumulation, and extends the time between forced regenerations, maintaining fuel economy by increasing contact points between soot and catalyst, and providing superior heat resistance and mechanical characteristics.
Implementation Method 1
soot combustion behavior by active oxygen induced by an oxide catalyst
Implementation Method 2
heating the honeycomb structured body
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3(a)~3(b)
AI summary
The present invention aims to provide a catalyst supporting honeycomb which can improve the continuous regeneration performance of soot and economically keep the amount of soot that accumulates with time on the cell walls small. The catalyst supporting honeycomb of the present invention includes a pillar-shaped honeycomb structured body having a plurality of cells formed in parallel with one another in a longitudinal direction with a cell wall interposed therebetween; and catalyst particles supported on the honeycomb structured body, the plurality of cells comprising a set of large-volume cells in which either end of each of the cells is sealed, and a set of small-volume cells in which the other end of each of the cells is sealed, the total area of the set of large-volume cells in the cross section perpendicular to the longitudinal direction being larger than the total area of the set of small-volume cells in the cross section perpendicular to the longitudinal direction, and the catalyst particles being configured by an oxide catalyst having an average particle diameter of 0.05 µm to 1.00 µm.