Hydrogen Combustion Catalyst Iodine Poisoning Resistance
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Solution Overview
Problem
Current hydrogen combustion catalysts used in nuclear power stations are susceptible to poisoning by iodine and moisture, leading to decreased activity, especially during core meltdown scenarios, and existing solutions do not effectively address iodine poisoning or the combustibility of organic resin carriers.
Innovation Solution
A hydrogen combustion catalyst with platinum and palladium supported on an inorganic oxide carrier, modified with a hydrophobic functional group and containing a specific range of chlorine, which mitigates iodine poisoning and maintains activity in the presence of moisture and iodine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a hydrophobic resin carrier is used to resist moisture, then moisture resistance is improved, but iodine poisoning resistance deteriorates and combustibility risk increases
Solution Approach 1:
The patent replaces the organic resin carrier with an inorganic oxide carrier that does not combust, effectively making the system disposable of its combustion risk while maintaining moisture resistance through hydrophobic modification. The inorganic carrier provides long-term stability without the inherent combustion risks of organic materials.
Solution Approach 2:
The patent changes the fundamental material parameter from organic resin to inorganic oxide, fundamentally altering the combustion properties from combustible to non-combustible while maintaining the hydrophobic surface properties needed for moisture resistance through chemical modification of the inorganic carrier surface.
2Object-affected harmful factors
If a hydrophobic resin carrier is used to resist moisture, then moisture resistance is improved, but combustibility risk increases
Solution Approach 1:
The patent eliminates the combustion risk by replacing the organic resin carrier with a non-combustible inorganic oxide carrier, effectively disposing of the combustion hazard while preserving the moisture-resistant functionality through hydrophobic surface modification.
Solution Approach 2:
The patent fundamentally changes the material parameter from organic to inorganic, transforming the combustion property from combustible to non-combustible while maintaining the hydrophobic characteristics necessary for moisture resistance through surface chemical modification.
3Reliability
If conventional catalysts are used without hydrophobic modification, then iodine poisoning resistance is maintained, but moisture adsorption increases leading to activity decrease
Solution Approach 1:
The patent applies hydrophobic modification locally to the carrier surface through chemical treatment with organosilane compounds, creating a hydrophobic surface layer that repels moisture while preserving the bulk inorganic oxide carrier's resistance to iodine poisoning. This local modification solves the moisture adsorption problem without affecting the overall iodine resistance.
4Productivity
If reaction temperature is raised to overcome iodine poisoning, then catalyst activity is improved, but the underlying poisoning problem persists
Solution Approach 1:
The patent converts the potential harm of iodine poisoning into a beneficial system where the inorganic oxide carrier inherently resists iodine adsorption, and the hydrophobic surface modification further protects the catalyst. This dual-protection system eliminates the need for temperature compensation and provides stable activity without underlying poisoning issues.
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 maintains hydrogen combustion reaction efficiency without significant activity decrease, even in iodine-containing atmospheres and moist conditions, and is applicable to various hydrogen combustion equipment, including nuclear power station hydrogen recombiners.
Implementation Method 1
a functional group having at least one alkyl group with three or less carbon atoms is bonded to a terminal of a hydroxyl group on the carrier surface by substitution
Implementation Method 2
platinum and palladium are supported as the catalyst metal
Implementation Method 3
causing hydrogen to undergo oxidation combustion (recombination) to water (water vapor)
Implementation Method 4
a chlorine content is 300 ppm to 2,000 ppm per 1 mass% of the total supported amount of a supported amount of platinum and a supported amount of palladium
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
The hydrogen combustion catalyst includes a catalyst metal supported on a carrier made of an inorganic oxide, wherein: a functional group having at least one alkyl group with three or less carbon atoms is bonded to a terminal of a hydroxyl group on the carrier surface by substitution; platinum and palladium are supported as the catalyst metal; and a chlorine content is 300 ppm to 2,000 ppm per 1 mass% of the total supported amount of a supported amount of platinum and a supported amount of palladium. The total supported amount of platinum and palladium is preferably 0.1 to 5.0 mass% based on mass of a whole catalyst. In the hydrogen combustion catalyst according to the present invention, when treating a gas that contains iodine and hydrogen, catalyst poisoning by iodine is suppressed.