Zirconia Composite Oxide for Thin Honeycomb Catalyst Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing zirconia-based porous bodies used as catalyst carriers in honeycomb structures face a trade-off between maintaining high catalyst performance and reducing pressure loss due to the thickness of the catalyst layer, leading to reduced exhaust gas ventilation and engine output.
Innovation Solution
A zirconia-based composite oxide with a high tap bulk density and specific surface area is developed, allowing for a thinner catalyst layer while maintaining sufficient exhaust gas purifying ability, achieved through controlled aggregation of primary and secondary particles during manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the thickness of the catalyst layer is reduced to decrease pressure loss, then engine output is improved, but exhaust gas purification performance deteriorates
Solution Approach 1:
The patent employs a zirconia-based porous body with specifically controlled pore size distribution (bimodal or multimodal distribution including mesopores of 2-50 nm and macropores of 50 nm or more) to achieve high specific surface area (30 m²/g or more after firing at 1000°C for 3 hours). This porous structure allows sufficient catalyst active sites within a thin layer, maintaining purification performance while reducing thickness and pressure loss.
Solution Approach 2:
The patent changes the physical and chemical parameters of the zirconia-based porous body, including pore size distribution, total pore volume (0.4 cc/g or more), and specific surface area, to optimize catalyst performance. By controlling these parameters, the catalyst layer can be made thinner while maintaining sufficient purification capability, thus reducing pressure loss without sacrificing exhaust gas treatment efficiency.
2Productivity
If the thickness of the catalyst layer is reduced to improve engine output, then ventilation amount increases, but catalyst performance decreases
Solution Approach 1:
The zirconia-based porous body with optimized pore structure (bimodal/multimodal distribution) provides high specific surface area within a thin layer, ensuring sufficient catalyst active sites are available even when the catalyst layer thickness is reduced to improve engine output and ventilation.
Solution Approach 2:
The patent uses a composite oxide system (zirconia-based) with specific pore structure characteristics to achieve both thin layer configuration and high catalyst performance, resolving the contradiction between reduced thickness for improved engine output and maintained purification effectiveness.
3Reliability
If the pore volume of mesopores to macropores is increased to maintain high specific surface area after heat treatment, then catalyst performance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent establishes specific parameter ranges for pore size distribution (mesopores 2-50 nm and macropores 50 nm or more), total pore volume (0.4 cc/g or more), and specific surface area (30 m²/g or more after firing). By defining these parameters, the manufacturing process becomes more controllable and less complex, as the focus is on achieving quantifiable targets rather than optimizing multiple variables simultaneously.
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 zirconia-based composite oxide enables effective exhaust gas treatment with reduced catalyst layer thickness, minimizing pressure loss and enhancing catalyst performance even at high temperatures.
Implementation Method 1
adding a sulfating agent to a zirconium salt solution having a temperature of 100° C. or higher while stirring the zirconium salt solution
Implementation Method 2
stirring the zirconium salt solution at stirring Reynolds number of 400 or more and 2000 or less
Implementation Method 3
a zirconia-based porous body having a specific surface area of at least 30 m2/g after firing at 1000° C. for 3 hours
Data Source
AI summary
The purpose of the present invention is to provide a zirconia-based composite oxide for making it possible to form a catalyst layer which, despite having a reduced thickness, has a sufficient quantity of catalyst to function in exhaust gas treatment on a wall of a honeycomb structure. The purpose of the present invention is also to provide a method for manufacturing said zirconia-based composite oxide. The present invention relates to a zirconia-based composite oxide characterized in that the tap bulk density thereof is 0.75 g/mL or greater, and the specific surface area thereof after heat treatment for three hours at 1000° C. is 45 m2/g or greater.