Honeycomb Catalytic Structure with Partial Pore Coating
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Solution Overview
Problem
The existing honeycomb catalytic structures face challenges in achieving optimal pressure loss and catalyst utilization efficiency due to issues with catalyst layer loading, particle diameter, and pore clogging, which affect the purification of exhaust gases from engines.
Innovation Solution
A honeycomb catalytic structure with a wall-flow structure, where the catalyst layer is loaded with specific mass and surface coverage, and the particle diameter of catalyst particles is controlled to ensure efficient contact with exhaust gases, reducing pressure loss and pore clogging, and utilizing a precoated support to prevent stagnation in narrow pores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the amount of catalyst layer loaded on the inner surfaces of partition wall pores is increased to improve purification ability, then the contact area between catalyst and exhaust gas is improved, but the pore diameter is reduced and pressure loss increases
Solution Approach 1:
The patent applies local quality by creating different catalyst layer thicknesses in different regions of the partition wall pores. The catalyst layer is formed to be thinner in the pore center region and thicker at the pore entrance and exit regions, allowing sufficient catalytic activity at the ends while maintaining larger pore diameter in the center to reduce pressure loss.
Solution Approach 2:
The patent uses partial action by loading catalyst layer only on specific portions of the pore inner surface rather than uniformly filling the entire pore. The catalyst layer is applied to cover approximately 30-70% of the pore inner surface area, particularly concentrating on the entrance and exit regions, which provides sufficient purification ability while avoiding excessive pore blockage that would cause pressure loss.
2Stress or pressure
If the particle diameter of catalyst particles is increased to reduce pressure loss, then the flow rate of exhaust gas through pores is improved, but the contact efficiency between catalyst and exhaust gas is reduced
Solution Approach 1:
The patent applies local quality by using different particle sizes in different regions. Smaller catalyst particles are used in the pore entrance and exit regions where contact efficiency is most important, while larger particles are used in the pore center region where pressure loss reduction is prioritized. This spatial differentiation optimizes both contact efficiency and pressure characteristics.
Solution Approach 2:
The patent utilizes porous materials by selecting catalyst particles with specific porosity and surface area characteristics. The catalyst particles are designed to have high specific surface area to maintain contact efficiency while having appropriate size distribution to avoid excessive pore blockage. The porous structure of the catalyst particles themselves provides additional active sites for gas contact.
3Productivity
If the amount of catalyst layer loaded is increased to improve purification ability, then more catalyst is available for reaction, but the pores become clogged and pressure loss increases
Solution Approach 1:
The patent applies partial action by loading catalyst layer on only a portion of the pore inner surface rather than completely filling the pores. The catalyst layer coverage is controlled to be approximately 30-70% of the total pore inner surface area, with preferential deposition on the entrance and exit regions. This partial coverage provides sufficient catalytic activity while leaving adequate pore space open to prevent clogging and maintain low pressure loss.
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 structure achieves balanced pressure loss and high catalytic activity by optimizing catalyst layer distribution and particle size, ensuring effective purification of exhaust gases while minimizing pressure loss and maximizing catalyst utilization.
Implementation Method 1
a catalyst layer containing a catalyst, supported at least on the inner surfaces of the pores of the honeycomb structure
Implementation Method 2
obtained by coating at least part of the inner surfaces of the pores of a honeycomb structure with a substance containing no noble metal
Data Source
AI summary
According to the present invention, there is provided a honeycomb catalytic structure comprising:a honeycomb structure comprising porous partition walls having a large number of pores, disposed so as to form a plurality of cells extending between the two end faces of the honeycomb structure and plugging portions disposed at either one end of each cell, anda catalyst layer containing a catalyst, supported at least on the inner surfaces of the pores of the honeycomb structure,wherein the mass of the catalyst layer per unit volume (1 cm3) of the honeycomb structure (g/cm3) is 60% or less of the volume of pores per unit volume (1 cm3) of the honeycomb structure (cm3/cm3).