Copper Oxide Zeolite Catalyst for Selective N2 Conversion
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Solution Overview
Problem
Current catalysts for purifying nitrogen-based exhaust gases containing organic nitrogen compounds or ammonia have limitations in selectivity for converting these compounds to N2, often producing undesirable by-products like NOx, HCN, NH3, and CO, and require complex preparation methods.
Innovation Solution
A catalyst composition formed by mixing copper oxide particles and zeolite particles, with optional inclusion of manganese oxide and precious metals like Pt, Pd, Ru, Rh, or Ir, which are supported on inorganic oxides, achieving high N2 selectivity and stability at temperatures between 250 to 600°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If precious metal catalysts such as platinum or palladium are used for treating nitrogen-based exhaust gas, then decomposition activity for organic nitrogen compounds and ammonia is improved, but selectivity for NOx increases leading to harmful by-products
Solution Approach 1:
The patent uses a composite catalyst system combining copper oxide particles (0.1-10 μm) with zeolite particles (0.3-5 μm) in specific weight ratios. This composite structure allows copper oxide to provide high decomposition activity while zeolite acts as a selective support that promotes N2 formation and suppresses NOx generation, resolving the contradiction between activity and selectivity
Solution Approach 2:
The patent applies local quality by controlling the particle size of copper oxide (0.1-10 μm) and zeolite (0.3-5 μm) particles, and their spatial distribution in the catalyst composition. The specific particle size ranges optimize the local catalytic sites for N2 selectivity while maintaining overall decomposition activity, preventing harmful NOx formation
2Ease of manufacture
If copper compound is used instead of vanadium oxide and tungsten oxide, then catalyst preparation is simplified, but decomposition activity deteriorates
Solution Approach 1:
The patent changes the particle size parameter of copper oxide to a specific range (0.1-10 μm) and optimizes its weight ratio relative to zeolite (1-80 parts copper oxide to 9-20 parts zeolite). These parameter changes enable simple copper compound preparation while achieving high decomposition activity that compensates for the absence of vanadium or tungsten oxides
3Manufacturing precision
If Cu compound supported on Al2O3 and zeolite is used, then N2 selection rate is improved, but preparation complexity increases
Solution Approach 1:
The patent segments the catalyst into two separate particle components - copper oxide particles (0.1-10 μm) and zeolite particles (0.3-5 μm) - that are mixed in specific weight ratios. This segmentation simplifies preparation compared to supported catalysts, as each component can be independently prepared and then combined, while maintaining high N2 selection rate through optimized particle size and ratio
4Object-generated harmful factors
If catalyst contains copper oxide, ZSM5 and/or zeolite β with MgO, CaO or AgO, then NOx purification is improved, but conversion to N2 decreases and CO and NH3 by-products increase
Solution Approach 1:
The patent extracts and eliminates MgO, CaO, and AgO from the catalyst composition, retaining only copper oxide and zeolite. This extraction removes the components that cause CO and NH3 by-product formation and reduce N2 conversion, while the copper oxide-zeolite composite maintains effective NOx purification through alternative catalytic pathways
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 catalyst composition effectively decomposes organic nitrogen compounds and ammonia into N2 with high selectivity, suppressing the formation of unwanted by-products and maintaining activity over long-term use, even in the presence of acidic components like SO2.
Implementation Method 1
a catalyst composition for purifying an exhaust gas containing an organic nitrogen compound, ammonia, or a combination thereof, the catalyst composition containing a copper oxide and zeolite
Implementation Method 2
decomposes an organic nitrogen-containing compound or a nitrogen-containing compound such as ammonia at a relatively low temperature to convert such a compound to N2 selectively, while suppressing the formation of a by-product such as NOx, HCN, NH3, or CO
Data Source
AI summary
The present invention provides a catalyst composition which can decompose an organic nitrogen compound at a relatively low temperature to convert the compound to N2 and render it harmless in the purification of an exhaust gas containing the compound (nitrogen-based exhaust gas); a catalyst containing the catalyst composition; a method for producing the catalyst; and an exhaust gas purification apparatus containing the catalyst.By using a catalyst composition formed by mixing copper oxide particles and zeolite particles, an organic nitrogen compound and/or ammonia can be converted to N2 highly selectively. The catalyst composition of the present invention may further contain a manganese oxide and/or a precious metal.