Ethylene Oxide Epoxidation Catalyst with Stable Chloriding Effectiveness
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Solution Overview
Problem
Existing ethylene epoxidation processes using silver-based catalysts with rhenium and alkali metal promoters require continuous monitoring and adjustment of chloride reaction modifier concentrations to maintain selectivity and stability, which is cumbersome and inefficient.
Innovation Solution
The process employs a fluoride-mineralized alpha-alumina carrier with silver, rhenium, and alkali metal promoters, maintaining a constant or narrow range of overall catalyst chloriding effectiveness value (Cleff) to simplify operations and stabilize ethylene oxide production without significant chloride concentration changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional silver-based catalysts with rhenium and alkali metal promoters are used, then ethylene oxide production can be achieved, but continuous monitoring and adjustment of chloride reaction modifier concentrations is required to maintain selectivity and stability
Solution Approach 1:
The catalyst system automatically maintains optimal chloriding effectiveness through the synergistic interaction of rhenium and alkali metal promoters, which self-regulate the chloride concentration effects on the silver sites. The rhenium promoter enhances chloride utilization while alkali metals modulate the electronic properties, creating a self-balancing system that maintains selectivity without external intervention.
Solution Approach 2:
The invention changes the fundamental parameters of the catalyst system by introducing rhenium and alkali metal promoters that alter the chloriding effectiveness value (Cleff) characteristics. This parameter transformation allows the catalyst to operate at optimal selectivity across a broader range of conditions, reducing the need for precise chloride concentration control.
2Manufacturing precision
If chloride reaction modifier concentration is continuously adjusted to maintain selectivity, then catalyst performance is optimized, but process complexity and operational burden increase
Solution Approach 1:
The catalyst system automatically maintains optimal chloriding effectiveness through the synergistic interaction of rhenium and alkali metal promoters, which self-regulate the chloride concentration effects on the silver sites. The rhenium promoter enhances chloride utilization while alkali metals modulate the electronic properties, creating a self-balancing system that maintains selectivity without external intervention.
Solution Approach 2:
The invention changes the fundamental parameters of the catalyst system by introducing rhenium and alkali metal promoters that alter the chloriding effectiveness value (Cleff) characteristics. This parameter transformation allows the catalyst to operate at optimal selectivity across a broader range of conditions, reducing the need for precise chloride concentration control.
3Productivity
If high selectivity is maintained throughout catalyst life, then ethylene oxide production efficiency improves, but catalyst composition and operation become more complex
Solution Approach 1:
The invention employs a composite catalyst system combining silver with rhenium and alkali metal promoters. This composite structure integrates multiple functional components: silver provides the primary epoxidation activity, rhenium enhances chloride utilization and stabilizes selectivity, and alkali metals modulate electronic properties. The synergistic combination achieves high productivity while managing complexity through functional integration.
Solution Approach 2:
The invention changes the fundamental parameters of the catalyst system by introducing rhenium and alkali metal promoters that alter the chloriding effectiveness value (Cleff) characteristics. This parameter transformation allows the catalyst to operate at optimal selectivity across a broader range of conditions, reducing the need for precise chloride concentration control.
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
This approach simplifies industrial ethylene oxide production by maintaining maximum selectivity and stability over the catalyst's life, reducing the need for continuous optimization and minimizing downstream purification equipment demands.
Implementation Method 1
ethylene is reacted with oxygen in the presence of an epoxidation catalyst, within an epoxidation reactor, to produce a gaseous stream at the outlet of the epoxidation reactor that comprises ethylene oxide
Implementation Method 2
the produced ethylene oxide is separated from the majority of the other gaseous constituents through contact with a recirculating solvent (commonly referred to as 'lean absorbent')
Data Source
AI summary
An ethylene oxide (EO) production process for the epoxidation of ethylene comprising:contacting an inlet feed gas with a catalyst having a fluoride-mineralized alpha-alumina carrier, silver, a rhenium promoter, and one or more alkali metal promoters.At a cumulative EO production cumEO1 of at least 0.2 kton EO/m3 catalyst, the process is operating at a reaction temperature T1 and with the inlet feed gas having an optimum overall catalyst chloriding effectiveness value Cleff<sub2>1 </sub2>to produce EO with an EO production parameter value EO1; andthe process is subsequently operated such that at a cumulative EO production cumEOX, cumEOX is at least 0.6 kton EO/m3 catalyst greater than cumEO1, the reaction temperature has an increased value TX to maintain EO production parameter EO1 whilst the optimum overall catalyst chloriding effectiveness value of the inlet feed gas Cleff<sub2>X </sub2>is controlled such that the ratio of Cleff<sub2>X</sub2>/Cleff<sub2>1 </sub2>is from 0.8 to 1.2.