Hydrocarbon Adsorption Complex with Core-Shell Zeolite Structure
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Solution Overview
Problem
Current hydrocarbon adsorbents fail to effectively adsorb and oxidize hydrocarbons at temperatures lower than those at which three-way catalysts are active, and they deteriorate in the presence of moisture, leading to inadequate performance during the cold start period of vehicle operation.
Innovation Solution
A hydrocarbon adsorption and desorption complex is developed, comprising a gas adsorbing portion with zeolite particles of a low silicon to aluminum (Si/Al) molar ratio and a reinforcing portion of silica-zeolite, where metal ions are bound to the zeolite and metal oxides are positioned at the interface, forming a core-shell structure to enhance adsorption and oxidation capabilities and hydrothermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If zeolite with high Al content (low Si/Al ratio) is used to increase hydrocarbon adsorption capacity, then adsorption ability is improved, but hydrothermal stability deteriorates
Solution Approach 1:
The adsorbent is divided into two distinct portions: a gas adsorbing portion containing zeolite with low Si/Al ratio for high hydrocarbon adsorption capacity, and a reinforcing portion containing zeolite with high Si/Al ratio for hydrothermal stability. This segmentation allows each portion to optimize its function without compromise.
Solution Approach 2:
The invention creates a composite structure by combining zeolite particles with different Si/Al ratios in a core-shell configuration. The gas adsorbing portion (core) uses low Si/Al ratio zeolite for maximum adsorption, while the reinforcing portion (shell) uses high Si/Al ratio zeolite for stability, achieving both objectives simultaneously.
2Quantity of substance
If zeolite structure is used for hydrocarbon adsorption, then adsorption ability is improved, but oxidation ability at low temperature deteriorates
Solution Approach 1:
The invention merges the advantages of two different zeolite compositions into a single adsorbent system. The gas adsorbing portion provides superior hydrocarbon adsorption capacity due to its low Si/Al ratio, while the reinforcing portion contributes oxidation ability, enabling the composite structure to perform both adsorption and oxidation functions effectively at low temperatures.
3Device complexity
If only zeolite is used for hydrocarbon adsorption, then simplicity is maintained, but performance in cold start period deteriorates
Solution Approach 1:
The adsorbent is segmented into functionally distinct portions: the gas adsorbing portion optimized for hydrocarbon adsorption and the reinforcing portion optimized for oxidation and stability. This segmentation enables the adsorbent to effectively treat hydrocarbons during the cold start period by combining adsorption and oxidation capabilities in a single structured material.
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 complex demonstrates improved hydrocarbon adsorption and oxidation abilities at lower temperatures and maintains stability even under high moisture conditions, achieving efficient hydrocarbon treatment and extended durability.
Implementation Method 1
a gas adsorbing portion containing zeolite particles, wherein a molar ratio of silicon to aluminum (Si/Al) of the zeolite particles is in a range from 1 to 50
Implementation Method 2
metal ions are bound to the zeolite particles of the gas adsorbing portion
Implementation Method 3
a reinforcing portion formed on a surface of the gas adsorbing portion, and containing silica-zeolite particles having the same structure as the zeolite particles of the gas adsorbing portion
Data Source
AI summary
Disclosed are a hydrocarbon adsorption and desorption complex that reduces emission of hydrocarbon from vehicle exhaust gas and improves hydrothermal stability of a device, and a method for preparing the same. The hydrocarbon adsorption and desorption complex may have improved adsorption ability of the hydrocarbon as metal ions are bound to a gas adsorbing portion containing aluminum, and may have improved hydrothermal stability as a reinforcing portion made of silica is formed on a surface of the gas adsorbing portion.