Phosphorus-Modified BEA Zeolite Heat Resistance
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Solution Overview
Problem
The BEA-type zeolite used in exhaust gas purifying compositions has excellent adsorption capacity for hydrocarbons but lacks sufficient heat resistance in severe thermal environments.
Innovation Solution
A phosphorus-containing BEA-type zeolite with a pore volume ratio of micropore to mesopore volume of 2.0 or more is developed, where the micropore volume has a pore diameter of 2 nm or less and the mesopore volume has a pore diameter of 2 nm to 100 nm, achieved by attaching a phosphorus-containing compound to the BEA-type zeolite and heat-treating it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a phosphorus-containing BEA-type zeolite with high micropore volume ratio is used, then heat resistance is improved, but adsorption capacity for hydrocarbons may be reduced
Solution Approach 1:
The patent applies parameter changes by precisely controlling the pore volume ratio (V2/V1 ≥ 2.0) and pore size distribution (micropores: 2 nm or less, mesopores: 2-100 nm) of the BEA-type zeolite. This optimization balances the micropore volume for adsorption capacity with the mesopore volume for heat dissipation and structural stability at high temperatures, resolving the contradiction between heat resistance and adsorption capacity.
Solution Approach 2:
The patent creates a composite material system by incorporating phosphorus-containing compounds into the BEA-type zeolite structure. This composite approach enhances the zeolite's heat resistance while maintaining its adsorption properties, as the phosphorus modification strengthens the framework structure without significantly reducing the effective pore volume for hydrocarbon adsorption.
2Productivity
If the exhaust gas temperature is increased to activate the catalyst, then purification efficiency is improved, but hydrocarbons are less likely to be adsorbed immediately after start-up
Solution Approach 1:
The patent applies preliminary action by designing the zeolite structure with pre-configured micropores and mesopores that enable hydrocarbon adsorption even at low temperatures during engine start-up. The optimized pore volume ratio (V2/V1 ≥ 2.0) ensures that the zeolite can adsorb hydrocarbons before the catalyst fully activates, preventing emissions during the critical start-up period.
Solution Approach 2:
The patent applies local quality by creating different functional zones within the zeolite structure: micropores (2 nm or less) for hydrocarbon adsorption and mesopores (2-100 nm) for heat transfer and structural stability. This spatial differentiation allows the zeolite to simultaneously provide low-temperature adsorption capability and high-temperature structural integrity.
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 phosphorus-containing BEA-type zeolite maintains its framework structure and enhances heat resistance, allowing it to effectively adsorb hydrocarbons even at high temperatures up to 1000°C, thus maintaining high purification performance.
Implementation Method 1
The BEA-type zeolite has excellent adsorption capacity for hydrocarbons (HC)
Implementation Method 2
a step of bringing the BEA-type zeolite into contact with a phosphorus-containing compound to attach the phosphorus-containing compound to the BEA-type zeolite
Data Source
AI summary
An exhaust gas purifying composition that contains a phosphorus-containing BEA-type zeolite and has further improved heat resistance; and a production method therefor are provided. The exhaust gas purifying composition contains a phosphorus-containing BEA-type zeolite, wherein the phosphorus-containing BEA-type zeolite has a pore volume ratio (V2/V1) of a micropore volume V2 having a pore diameter in a range of 2 nm or less, as measured by a SF method, to a mesopore volume V1 having a pore diameter in a range of 2 nm or more and 100 nm or less, as measured by a BJH method, of 2.0 or more.