Supported Hybrid Vanadium-Chromium Catalyst for Polyethylene
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Solution Overview
Problem
Current polyethylene catalysts lack the ability to produce polyethylene resins with broad molecular weight distribution and optimal comonomer content, limiting the formation of high-performance polyethylene products.
Innovation Solution
A supported hybrid vanadium-chromium-based catalyst is developed by adding vanadium to an organic chromium-based catalyst, which enhances molecular weight distribution and comonomer content, particularly increasing high molecular weight comonomer content and reducing low molecular weight comonomer content, thereby improving polymer performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional chromium catalysts are used, then polyethylene production is achieved, but molecular weight distribution is narrow and comonomer content is limited
Solution Approach 1:
The patent combines vanadium and chromium catalyst components into a single hybrid catalyst system. The vanadium-chromium synergistic combination allows simultaneous control of molecular weight distribution and comonomer content, resolving the contradiction between producing broad MWD and controlling comonomer distribution.
Solution Approach 2:
The invention creates a composite catalyst system integrating multiple metal centers (vanadium and chromium) with organic ligands on a support matrix. This composite structure enables independent optimization of different catalytic functions: vanadium controls MWD while chromium manages comonomer incorporation, eliminating the trade-off present in single-component catalysts.
2Quantity of substance
If single-component chromium catalysts are used, then catalytic activity is maintained, but comonomer content in high molecular weight part is insufficient
Solution Approach 1:
By merging vanadium and chromium catalyst components, the hybrid system achieves both high catalytic activity and enhanced comonomer content in high molecular weight fractions. The vanadium component contributes to high-temperature stability and comonomer incorporation, while chromium maintains overall catalytic activity.
3Adaptability or versatility
If vanadium is added to chromium catalyst, then molecular weight distribution is broadened, but catalyst complexity increases
Solution Approach 1:
The patent applies local quality by assigning specific functional roles to different catalyst components within the hybrid system. Vanadium is positioned to control molecular weight distribution, while chromium handles comonomer content. This functional differentiation allows broad MWD without proportionally increasing overall system complexity.
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 novel catalyst exhibits high activity and produces polyethylene with broad molecular weight distribution, leading to higher performance polyethylene products with improved mechanical and chemical properties.
Implementation Method 1
a novel supported double center hybrid polyethylene catalyst... By adding vanadium activity component to an organic chromium based catalyst
Data Source
AI summary
The present invention relates to a carriered hybrid vanadium-chromium-based catalyst, characterized in the catalyst is carriered on a porous inorganic carrier and a V active site and an organic Cr active site are present on the porous inorganic carrier at the same time. The present invention further relates to a process for producing a carriered hybrid vanadium-chromium-based catalyst. The catalyst of the present invention can be used for producing ethylene homopolymers and ethylene/α-olefin copolymers. The hybrid vanadium-chromium-based catalyst can have high activity and produce polyethylene polymers having the properties of broad molecular weight distribution (Part of the products are bimodal distribution) and excellent α-olefin copolymerization characteristic.