Metathesis Catalyst System for Low-Temperature Propylene Production
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Solution Overview
Problem
High reaction temperatures in metathesis processes for propylene production lead to shorter catalyst life, increased production costs, and lowered product yield, as seen in existing methods for producing propylene from butene and ethylene using tungsten catalysts.
Innovation Solution
A propylene production process with a catalyst system that includes a higher concentration of metathesis catalyst than isomerization catalyst, where the olefin feed contacts the isomerization catalyst prior to or simultaneously with the metathesis catalyst, and the catalysts are activated independently at specific temperatures, using a binder with an alpha crystalline structure and magnesium oxide, operating at reaction temperatures between 110°C to 200°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high reaction temperatures (greater than 300°C) are used in metathesis processes, then propylene production rates are improved, but catalyst life is shortened and production costs increase
Solution Approach 1:
The patent changes the temperature parameter from conventional high temperatures (>300°C) to a lower temperature range (100-200°C). This parameter change is achieved through the use of a specific catalyst system comprising tungsten oxide supported on a silica-alumina载体 with specific surface area and pore structure, which maintains high propylene production rates while extending catalyst life and reducing production costs
2Productivity
If high reaction temperatures (greater than 300°C) are used in metathesis processes, then propylene production rates are improved, but product yield is lowered
Solution Approach 1:
The patent lowers the reaction temperature parameter to 100-200°C while using a optimized catalyst system (tungsten oxide on silica-alumina with specific physical properties). This parameter change simultaneously improves product yield and maintains acceptable propylene production rates, eliminating the trade-off present in conventional high-temperature processes
3Ease of manufacture
If a single process using mixture of metathesis and isomerization catalyst is used, then process efficiency is improved, but reaction temperature requirements increase to greater than 300°C
Solution Approach 1:
The patent changes the temperature parameter to a lower range (100-200°C) while maintaining the single-process efficiency benefit. This is achieved through a carefully designed catalyst system where tungsten oxide is supported on silica-alumina with specific surface area (300-600 m²/g) and pore volume (0.3-0.6 mL/g), allowing the process to operate efficiently at reduced temperatures
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 process achieves propylene selectivity of at least 85 wt.% and catalyst stability of at least 24 hours, with increased productivity and reduced temperature requirements, maintaining high propylene production efficiency.
Implementation Method 1
a metathesis reactor loaded with a mixture of metathesis catalyst and an isomerization catalyst
Implementation Method 2
contact with an inert gas at an activation temperature in a range of 300 °C to 600 °C
Data Source
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AI summary
Propylene production processes are discussed herein. The propylene production processes may include contacting an olefin feed including butene with ethylene in the presence of a catalyst system including a metathesis catalyst under reaction conditions sufficient to form a product stream including propylene, wherein the metathesis catalyst includes molybdenum and the reaction conditions include a reaction temperature of less than 250 °C.