Metallocene Catalyst Formulation for Gas Phase Polymerization Gel Control
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Solution Overview
Problem
Current polymerization processes face challenges with gel formation due to agglomeration of small, hot catalyst particles and un-bound active species in gas phase polymerization reactors, which affects the quality and consistency of polymer products.
Innovation Solution
The development of catalyst formulations incorporating metallocene and stearyl containing compounds, such as bis 2-hydroxyethyl stearyl amine and aluminum distearate, which are pre-blended and used in conjunction with a calcined support to reduce agglomeration and scavenging of active species, and injected into the reactor via an effervescent catalyst injector with optimized support tube velocity to enhance dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If catalyst particles are used in gas phase polymerization, then polymerization reaction occurs, but small hot catalyst particles agglomerate causing gel formation
Solution Approach 1:
The patent introduces a support material as an intermediary carrier to hold the metallocene catalyst. The support acts as a mediator that prevents direct contact and agglomeration of catalyst particles while still allowing reactant access. This resolves the contradiction by enabling the polymerization reaction to proceed through the supported catalyst system without the harmful agglomeration effect.
Solution Approach 2:
The patent employs porous support materials with specific pore size distributions to accommodate catalyst particles. The porous structure provides a framework that physically separates catalyst particles, preventing agglomeration while allowing monomer diffusion. This approach maintains polymerization productivity while eliminating gel formation caused by particle agglomeration.
2Productivity
If catalyst particles are injected into reactor, then polymerization proceeds, but un-bound active species cause gel formation
Solution Approach 1:
The support material serves as an intermediary that binds and stabilizes the metallocene catalyst, preventing un-bound active species from causing gel formation. The support-catalyst interaction ensures that active species remain controlled and localized, eliminating the harmful effect while preserving polymerization productivity.
Solution Approach 2:
The patent performs preliminary blending of the metallocene catalyst with the support material and stearyl containing compounds before reactor injection. This pre-treatment ensures proper binding and distribution of active species on the support, preventing un-bound species from causing gel formation during the polymerization reaction.
3Object-affected harmful factors
If catalyst components are pre-blended, then agglomeration is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent creates a composite catalyst formulation by combining metallocene, support material, and stearyl containing compounds into a single integrated system. This composite structure inherently prevents agglomeration through the designed hierarchical architecture, reducing the need for complex manufacturing processes while achieving the desired anti-agglomeration effect.
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 effectively reduces gel formation and improves the quality of polymers by minimizing agglomeration and enhancing the interaction of catalyst components with polymerization reactants, leading to more uniform and higher-quality polymer products.
Implementation Method 1
injected into the reactor via an effervescent catalyst injector with optimized support tube velocity to enhance dispersion
Data Source
AI summary
Embodiments of the present disclosure are directed towards catalyst formulations including a metallocene and a stearic compound selected from bis 2-hydroxyethyl stearyl amine, aluminum distearate, and combinations thereof, where the metallocene is represented by the following formula: (Formula (I)) wherein each n-PR is n-propyl, and each X is independently CH3, Cl, or F.