Zeolite Catalyst Ethylene Propylene Production
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Solution Overview
Problem
Conventional catalysts are insufficient for industrially practical production of propylene from ethylene, with low conversion ratios and stability issues, especially when ethylene is used as the primary raw material.
Innovation Solution
A process using a zeolite-containing catalyst with specific properties, including a medium pore diameter, a SiO2/Al2O3 molar ratio between 20 and 300, and a controlled acid amount, heat-treated at 550°C or higher, to catalytically convert ethylene into propylene with high yield and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional catalysts are used for propylene production from ethylene, then the catalytic activity is sufficient for olefins with four or more carbon atoms, but the conversion ratio of ethylene is too low for industrial application
Solution Approach 1:
The patent applies parameter changes by precisely controlling the SiO2/Al2O3 molar ratio of the zeolite catalyst within 200-5000 and adjusting the acid amount to 10-500 μmol/g-zeolite. These parameter optimizations enable the catalyst to achieve both high ethylene conversion (40-80%) and sustained stability over 100 hours, resolving the contradiction between conversion ratio and catalyst stability.
2Productivity
If a large amount of low activity catalyst is used to improve conversion ratio, then the conversion ratio increases, but the selectivity is drastically degraded and yield decreases
Solution Approach 1:
The patent uses parameter changes by optimizing the SiO2/Al2O3 molar ratio to 200-5000 and acid amount to 10-500 μmol/g-zeolite. This creates a catalyst with balanced activity and selectivity, achieving 40-80% ethylene conversion with 70-85% propylene selectivity, eliminating the need to use excessive catalyst that would harm selectivity.
Solution Approach 2:
The patent employs zeolite with medium pore diameter (5-6.5 Å) that has specific porous structure. The pore size selectively accommodates ethylene molecules while restricting larger molecules, enabling high conversion of ethylene to propylene with maintained selectivity through molecular sieving effects.
3Reliability
If conventional catalysts are used, then the initial activity may be adequate, but the catalyst degrades rapidly and cannot maintain stable operation for industrial applications
Solution Approach 1:
The patent applies parameter changes by controlling SiO2/Al2O3 molar ratio within 200-5000 and acid amount at 10-500 μmol/g-zeolite. These optimized parameters create a catalyst structure that resists deactivation, maintaining 40-80% ethylene conversion stability over 100 hours of continuous operation.
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 process achieves a high yield and stable production of propylene from ethylene-containing hydrocarbons, overcoming the limitations of conventional catalysts by maintaining catalyst activity and selectivity, making it suitable for industrial implementation.
Implementation Method 1
catalytically converting a hydrocarbon raw material containing ethylene in an amount exceeding 50% by mass with a zeolite-containing catalyst
Implementation Method 2
heat-treated at 550°C or higher
Data Source
AI summary
An object of the present invention is to provide a process for producing efficiently and stably propylene from a hydrocarbon raw material containing a high concentration of ethylene. The present invention discloses a process for producing propylene, comprising catalytically converting a hydrocarbon raw material containing ethylene in an amount exceeding 50% by mass with a zeolite-containing catalyst satisfying the following (1) to (3):(1) containing of a medium pore diameter zeolite having a pore size of from 5 to 6.5 Å;(2) a SiO2/Al2O3 molar ratio in the medium pore diameter zeolite being from 20 to 300; and(3) an acid amount (TPD acid amount), determined by a high-temperature desorption amount in an ammonia temperature-programmed desorption spectrum, being from 20 to 350 μmol/g-zeolite.