Olivine Catalyst Converter for Low-Temperature NOx Reduction
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Solution Overview
Problem
Current catalytic converters struggle to efficiently reduce nitrogen oxides (NOx) at low temperatures and are costly, particularly in diesel vehicles, necessitating the development of low-cost alternatives that can operate effectively at cold start conditions and in stationary traffic scenarios.
Innovation Solution
A catalytic converter using a material of olivine composition, specifically Mg x Fe 2-x SiO 4, which catalyzes the reduction of NOx to nitrogen and oxidation of carbon monoxide at low temperatures, often room temperature, and is inexpensive to manufacture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Platinum Group Metals (PGMs) are used on alumina substrates for CO oxidation, then catalytic activity is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive PGM catalysts with a cheaper iron-based olivine material. Although PGMs provide high catalytic activity, the invention accepts using a less expensive material that can be manufactured more cost-effectively, aligning with the principle of substituting expensive materials with cheaper alternatives for the same function.
Solution Approach 2:
The invention changes the chemical composition parameters of the catalyst from PGMs to iron-based olivine material with specific stoichiometry (Mg,Fe)2-xSiO4. This parameter change in material composition enables cost reduction while maintaining catalytic functionality for CO oxidation and NOx reduction.
2Productivity
If conventional catalysts are used for NOx reduction, then catalytic conversion is achieved, but efficiency at low temperatures deteriorates
Solution Approach 1:
The patent modifies the catalyst composition to iron-based olivine material with specific stoichiometric ratios, which changes the thermal and catalytic properties. This parameter change enables the catalyst to achieve high NOx reduction efficiency at low temperatures including cold start conditions, unlike conventional PGM-based catalysts.
Solution Approach 2:
The invention uses a composite olivine material containing multiple elements (Mg, Fe, Si, O) in specific ratios. This composite structure provides enhanced low-temperature catalytic activity for both CO oxidation and NOx reduction simultaneously, resolving the temperature efficiency problem.
3Ease of manufacture
If Fe based catalysts are used for CO oxidation, then cost is reduced, but longevity deteriorates due to sulfide formation
Solution Approach 1:
The patent creates a composite olivine material where iron is combined with magnesium and silicon in a specific crystalline structure (Mg,Fe)2-xSiO4. This composite structure protects the iron from sulfide formation by incorporating it into a stable olivine lattice, thereby maintaining catalyst longevity while using cheaper iron-based materials.
Solution Approach 2:
The invention changes the chemical environment of iron by incorporating it into an olivine structure with controlled stoichiometry. This parameter change in the chemical structure prevents sulfide formation that would normally deactivate iron catalysts, thus improving reliability while maintaining low cost.
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 olivine-based catalytic converter efficiently converts NOx and CO to benign compounds like N2 and CO2, even at low temperatures, reducing emissions in various engine systems, including diesel engines, without the need for reheating and offering cost-effective solutions for both mobile and stationary applications.
Implementation Method 1
A catalytic converter using a material of olivine composition, specifically Mg x Fe 2-x SiO 4, which catalyzes the reduction of NOx to nitrogen
Implementation Method 2
oxidation of carbon monoxide at low temperatures, often room temperature
Data Source
Figure 1~2(i)
Figure 3(a)~3(b)
Figure 4
AI summary
A catalytic converter including a catalyst,the catalyst comprising a material of olivine composition, an engine comprising this catalytic converter and an method of producing nitrogen from NOx comprising the catalytic reduction of NOx by a catalyst comprising of a material of olivine composition. In addition, the use of a material of olivine composition in a catalytic reduction of NOx and a method of manufacture of a catalytic converter comprising adding the catalyst to a wash coat, applying the catalyst containing wash coat to a substrate and annealing the coated substrate.