Exhaust Catalyst N2O Suppression via Cu-CHA Zeolite
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Solution Overview
Problem
Current SCR systems generate nitrous oxide (N2O) as a side reaction during NOx reduction, leading to emissions that contribute to greenhouse gases, which are regulated and need to be minimized.
Innovation Solution
An exhaust gas purification catalytic device is designed with catalyst layers containing Cu-CHA zeolite particles and iron-supporting metal oxide particles, where the iron is supported on metal oxide particles such as alumina, titania, or ceria, and the ratio of these particles is optimized to enhance the proximity and interaction, thereby suppressing N2O emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a first catalyst composition layer comprising a mixed oxide and a second catalyst composition layer comprising a metal-exchanged zeolite are disposed on a substrate in this order from the upstream side, then N2O emissions can be decreased, but the device complexity increases due to multiple layers and components
Solution Approach 1:
The patent combines Cu-CHA zeolite particles and iron-supporting metal oxide particles into a single catalyst layer, merging the functions of multiple catalyst layers into one integrated layer. This reduces device complexity while maintaining the N2O emission reduction capability through the synergistic interaction between the two catalyst components within the same layer.
Solution Approach 2:
The patent creates a composite catalyst layer containing both Cu-CHA zeolite and iron-supporting metal oxide particles. This composite structure allows the two different catalyst materials to work together in close proximity, achieving effective N2O suppression while simplifying the overall device structure compared to separate layers.
2Object-generated harmful factors
If Cu-CHA zeolite particles and iron-supporting metal oxide particles are mixed in the same catalyst layer, then N2O emissions are greatly suppressed, but the manufacturing precision requirements increase due to particle ratio and distribution control
Solution Approach 1:
The patent specifies precise parameter ranges for the catalyst composition, including iron content (0.3-1.3 g/L as Fe2O3) and the mass ratio of iron-supporting metal oxide particles to Cu-CHA zeolite particles (5-20%). By defining these parameters with specific ranges, the patent balances manufacturing precision requirements with effective N2O suppression performance.
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 device effectively reduces N2O emissions by increasing the proximity of Cu-CHA zeolite and iron-supporting metal oxide particles within the same catalyst layer, ensuring efficient decomposition of N2O and minimizing its slip, thus meeting stringent greenhouse gas regulations.
Implementation Method 1
an exhaust gas purification catalytic device, comprising: a substrate and one or more catalyst layers on the substrate, wherein of the one or more catalyst layers, at least one catalyst layer comprises both Cu-CHA zeolite particles, and iron-supporting metal oxide particles
Data Source
AI summary
A gas purification catalyst device comprises: a substrate; and one or more catalyst layers on the substrate. Among the one or more catalyst layers, at least one catalyst layer contains both Cu-CHA-type zeolite particles and iron-supporting metal oxide particles in which iron is supported on metal oxide particles.