Coated Catalyst for Oxygen Removal from Hydrocarbon Gas Mixtures
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Solution Overview
Problem
Catalytic oxidative purification of gas mixtures with high hydrocarbon and oxygen concentrations is ineffective at temperatures below the light-off temperature, leading to inactive catalysts and potential runaway reactions, and existing solutions either require additional apparatus or increase catalyst production costs.
Innovation Solution
A coated catalyst composed of a shaped catalyst support with an outer shell containing gold and noble metals like palladium, platinum, rhodium, or iridium, without alkali metals, is used to convert oxygen into carbon dioxide and water, minimizing by-products and preventing explosions by concentrating active components on the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a catalyst is used for oxidative purification of gas mixtures with high hydrocarbon and oxygen concentrations, then oxygen removal efficiency is improved, but the risk of explosive oxidation reactions increases due to high light-off temperature requirements
Solution Approach 1:
The patent changes the chemical composition parameters of the catalyst by using a bimetallic system (palladium-gold or palladium-platinum) instead of conventional single-metal catalysts. This compositional parameter change enables the catalyst to achieve high oxygen removal efficiency at lower temperatures, thereby reducing the risk of explosive oxidation reactions while maintaining high productivity.
Solution Approach 2:
The patent employs composite catalyst materials consisting of palladium combined with gold or platinum. This composite approach allows the catalyst to achieve synergistic effects where the combination of metals provides both high catalytic activity for oxygen removal and reduced temperature requirements, thus resolving the contradiction between productivity and safety.
2Temperature
If the light-off temperature of the catalyst is decreased by doping with alkali metals, then catalytic activity at lower temperatures is improved, but catalyst production costs increase
Solution Approach 1:
Instead of using alkali metal doping to lower the light-off temperature, the patent changes the metallic composition parameters by incorporating gold or platinum into the palladium catalyst system. This approach achieves temperature reduction without requiring additional dopants, thereby avoiding the increased production costs associated with alkali metal doping while still achieving low-temperature catalytic activity.
3Productivity
If conventional catalysts are used for oxidative purification, then oxygen removal is achieved, but by-products are formed and catalyst effectiveness is reduced
Solution Approach 1:
The patent optimizes the metallic composition parameters by using specific palladium-gold or palladium-platinum ratios. This compositional parameter change enables selective catalysis that promotes complete oxidation to carbon dioxide and water while minimizing the formation of harmful by-products, thus improving both productivity and product quality.
Solution Approach 2:
The bimetallic composite catalyst system provides enhanced selectivity compared to conventional single-metal catalysts. The combination of palladium with gold or platinum creates synergistic effects that favor complete oxidation reactions, thereby reducing by-products formation while maintaining high oxygen removal rates.
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 process achieves high oxygen conversion efficiency at lower temperatures, reducing the risk of explosions and minimizing by-products, while maintaining catalyst effectiveness and reducing production costs.
Implementation Method 1
the oxygen is reacted with the hydrocarbon to form carbon dioxide and water
Implementation Method 2
Catalytic, oxidative purification has already been practiced for a long time
Data Source
AI summary
Oxygen is effectively removed from hydrocarbon-containing gas streams while minimizing danger of explosion by contacting the gas stream with a catalyst comprising shaped bentonite supports having an outer shell containing catalytic metals gold, and at least one of palladium platinum, rhodium, or iridium.