Pd-Pt Multi-Layer Catalyst Gauze for Ammonia Oxidation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Catalyst gauzes used in ammonia oxidation to NO produce N2O as a by-product, leading to mechanical weakness, limited technical life, and increased pressure drop, which affects the efficiency and stability of the process, and the high cost of Pd-based gauzes exacerbates these issues.
Innovation Solution
A multi-layer interlinked catalyst gauze structure with a Pd-rich first layer and a Pt-rich second layer, where the second layer acts as reinforcement, providing mechanical strength and reducing the tendency to fuse, while maintaining catalytic activity and optimizing material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If Pd-based catalyst gauze is used to reduce N2O production, then N2O reduction is achieved, but mechanical strength deteriorates causing breaks during use
Solution Approach 1:
The patent applies composite materials by combining Pd-based wire (for N2O reduction) with Pt-based or stronger alloy wire (for mechanical strength) in a single interlinked gauze structure. The stronger wire material forms a composite reinforcement within the Pd-based catalyst gauze, allowing the gauze to maintain both catalytic activity for N2O reduction and sufficient mechanical strength to prevent breaks during use.
2Strength
If thicker wire is used to strengthen Pd-based catalyst gauze, then mechanical strength is improved, but pressure drop increases reducing process efficiency
Solution Approach 1:
The patent applies local quality by providing mechanical reinforcement only at specific locations where strength is needed, rather than uniformly thickening the entire gauze wire. The stronger wire material is interlinked with the Pd-based wire to create localized reinforcement zones that prevent breaks without significantly increasing the overall wire diameter or surface area that would cause pressure drop.
3Object-generated harmful factors
If multiple Pd-based catalyst gauzes are used in series, then N2O reduction is enhanced, but they fuse together reducing contact time and increasing pressure drop
Solution Approach 1:
The patent applies merging by combining multiple catalyst gauze layers into a single interlinked structure. Instead of using separate Pd-based gauzes stacked in series that may fuse together, the invention creates one integrated gauze where Pd-based wires from different functional layers are mechanically interconnected through the stronger wire material, maintaining spatial separation of catalytic zones while preventing fusion during use.
4Strength
If more Pd-based wire is used to increase gauze strength, then mechanical strength is improved, but cost increases due to expensive precious metals
Solution Approach 1:
The patent applies parameter changes by altering the material composition parameter of the gauze structure. Instead of increasing the quantity of Pd wire, the invention changes the wire material parameter to include stronger alloys or Pt-based wires that provide superior mechanical properties. This parameter substitution maintains or improves strength while reducing dependence on large quantities of Pd, thereby lowering costs.
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 multi-layer structure enhances mechanical strength, extends the catalyst gauze's operational life, reduces N2O production, and maintains high performance by minimizing local deviations and pressure drop, allowing for longer and more stable ammonia oxidation processes with reduced precious metal usage.
Implementation Method 1
catalyst gauzes made from Pd or Pd-rich wire used downstream of a traditional Pt-based catalyst gauze may be used to reduce the amount of N 2 O produced. This probably works by dissociation of N 2 O molecules.
Implementation Method 2
This probably works by dissociation of N 2 O molecules.
Implementation Method 3
the second wire material forms a reinforcement of the Pd-based mechanical structure... making the catalyst gauze mechanically stronger during operation or use
Data Source
Figure 1~2
AI summary
Catalyst gauze (1) for the reduction of the amount of N2O in an ammonia oxidation process, containing a first layer (2) of woven or knitted first wire material (4), whereby said first wire material (4) is made from Pd or a Pd-rich alloy, whereby said first layer (2) contains a reinforcement in the form of a second wire material (5) which is woven or knitted among the first wire material (4) and which has a different composition than the first wire material (5).