Low Density Honeycomb Filter for Exhaust Particulate Regeneration
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Solution Overview
Problem
Existing exhaust gas filters with supported oxide catalysts face challenges in reducing energy consumption for particulate regeneration and effective burning of particulates, as the noble metal catalysts are not adequately utilized due to insufficient contact with particulates.
Innovation Solution
A honeycomb structured body with an oxide catalyst, excluding noble metals, is designed to have a low apparent density of 0.7 g/cm³ or less, supporting compounds like CeO₂, ZrO₂, and CuO, and a catalyst carrier with a noble metal catalyst is placed upstream to enhance particulate burning efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an oxide catalyst is supported on the exhaust gas filter to lower the burning temperature of particulates, then the burning temperature is reduced, but the energy required for further burning and removing particulates is reduced
Solution Approach 1:
The invention changes the physical parameter of the filter by controlling its apparent density to be 0.55 g/cm³ or less. This parameter change allows the filter to heat up more quickly and reach the temperature needed for particulate burning, thereby solving the contradiction between lowering burning temperature and maintaining sufficient energy for regeneration.
Solution Approach 2:
The invention introduces a two-stage regeneration process where the filter operates dynamically: first heating up quickly due to low apparent density, then maintaining burning temperature through controlled oxygen supply. This dynamic approach allows the system to adapt to different operational requirements and resolve the energy contradiction.
2Object-generated harmful factors
If a noble metal catalyst is supported together with the oxide catalyst to convert toxic gas components, then toxic gas conversion is improved, but the noble metal catalyst is not allowed to function effectively from the viewpoint of burning particulates
Solution Approach 1:
The invention extracts the noble metal catalyst from the filter structure itself and places it on a separate catalyst carrier positioned upstream. This separation allows the noble metal catalyst to function effectively for both toxic gas conversion and particulate burning without the interference of the oxide catalyst, resolving the contradiction between toxic gas conversion and particulate burning effectiveness.
Solution Approach 2:
The invention segments the catalytic functions by placing the noble metal catalyst and oxide catalyst in different locations within the exhaust system. The noble metal catalyst is positioned upstream on a separate carrier, while the oxide catalyst remains on the filter, allowing each catalyst to perform its optimal function without interfering with the other.
3Quantity of substance
If the noble metal catalyst is highly dispersed by Al2O3 to reduce cost, then the amount of noble metal catalyst is reduced, but the noble metal catalyst is hardly made in contact with particulates
Solution Approach 1:
The invention introduces a catalyst carrier as an intermediary structure that holds the highly dispersed noble metal catalyst in a position where it can effectively contact particulates. The carrier acts as a mediator between the dispersed catalyst particles and the particulates, ensuring sufficient contact area and effectiveness while maintaining low catalyst quantity.
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 configuration improves the regenerating rate of the honeycomb structured body by ensuring better contact between the oxide catalyst and particulates, reducing energy consumption, and eliminating the need for expensive noble metal catalysts, while efficiently purifying exhaust gases.
Implementation Method 1
supporting the oxide catalyst in an exhaust gas filter, the burning temperature of particulates is lowered so that the particulates can be efficiently burned
Implementation Method 2
The particulates can be burned and eliminated by using heating means such as a heater
Implementation Method 3
the noble metal catalyst is supported together with the oxide catalyst, although toxic gas components, such as CO and HC, in exhaust gases can be converted (oxidized)
Data Source
Figure 3
Figure 4(a)~4(b)
Figure 5(a)~5(b)
AI summary
The present invention provides a honeycomb structured body which can positively purify captured particulates and which has a high regenerating rate. The honeycomb structured body of the present invention comprises a plurality of cells placed in parallel with one another in a longitudinal direction with a cell wall therebetween, wherein an oxide catalyst is supported on at least one portion of the cell wall, and the honeycomb structured body has an apparent density of 0.7 g/cm3 or less.