Ethylene Oxide Catalyst with Cesium and Rhenium
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Solution Overview
Problem
Conventional catalysts for producing ethylene oxide, which include silver (Ag) and rhenium (Re) as main components, have unclear mechanisms for the effects of alkali metals and require precise control of silicon (Si) and sodium (Na) content in the carrier to optimize performance.
Innovation Solution
A catalyst comprising silver (Ag), cesium (Cs), rhenium (Re), and a carrier with a specific surface area of 0.6 to 3.0 m2/g, a Si to Na weight ratio of 2 to 50, and a Re content of 170 to 600 ppm, with a molar ratio of Cs to Re between 0.3 and 19, is developed, enhancing the co-catalyst effect of Re and maintaining high selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the Si and Na content in the carrier is precisely controlled to optimize catalyst performance, then the selectivity and co-catalyst effect are improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent applies parameter changes by establishing specific ranges for SiO2 (0.1-10 wt%), Na2O (0.01-5 wt%), and their ratio (SiO2/Na2O), rather than requiring precise control of individual components. This parameter-based approach simplifies manufacturing while achieving optimal catalyst performance through the synergistic relationship between these parameters.
2Reliability
If the Re content in the catalyst is increased to enhance co-catalyst effect, then the selectivity improves, but the catalyst cost increases
Solution Approach 1:
The patent optimizes the Re content to a specific range of 170-600 ppm per 1 m2/g of carrier surface area, rather than using high amounts of Re. This parameter optimization achieves effective co-catalyst activity while minimizing material cost, demonstrating that moderate Re levels combined with appropriate Si/Na ratio are sufficient for high performance.
3Duration of action of stationary object
If the specific surface area of the carrier is increased to improve catalyst dispersion, then the catalyst life is extended, but the manufacturing complexity increases
Solution Approach 1:
The patent specifies a moderate specific surface area range of 0.6-3.0 m2/g for the carrier, rather than using high surface area materials that require complex production processes. This parameter selection achieves adequate catalyst dispersion and extended catalyst life while maintaining manufacturing simplicity and cost-effectiveness.
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 exhibits improved selectivity and catalyst life, with the specific composition and pretreatment process optimizing the distribution of Cs and Re on the carrier surface.
Implementation Method 1
Catalysts used for producing ethylene oxide from ethylene contain silver (Ag) as a main component which is supported on a carrier
Data Source
AI summary
There is provided a catalyst for producing ethylene oxide from ethylene which is composed of at least silver (Ag), cesium (Cs), rhenium (Re) and a carrier, and can be improved, in particular, in selectivity.The present invention relates to a catalyst for producing ethylene oxide from ethylene, comprising at least silver (Ag), cesium (Cs), rhenium (Re) and a carrier, said catalyst being produced by optionally pretreating the carrier to support an alkali metal thereon and then supporting Ag, Cs and Re on the carrier, wherein the carrier has a specific surface area of 0.6 to 3.0 m2/g and a weight ratio of a silicon (Si) content to a sodium (Na) content of 2 to 50 in terms of SiO2/Na2O; a content of Re in the catalyst is 170 to 600 ppm per 1 m2/g of the specific surface area of the carrier on the basis of a weight of the carrier; and a molar ratio of Cs to Re in the catalyst is 0.3 to 19.