Zoned Silica-Supported Metallocene Catalyst for Uniform Polyolefin Powder
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Solution Overview
Problem
Existing metallocene catalysts used in olefin polymerization processes face challenges in achieving both high olefin polymerization activity and uniform polyolefin powder morphology, leading to issues such as reactor fouling and inefficient process productivity due to non-uniform particle shapes.
Innovation Solution
A method involving the sequential support of aluminum alkyl halide, cocatalyst compound, and metallocene compound on a silica-based carrier, where aluminum alkyl halide is primarily supported on the surface and cocatalyst compound inside the pores, enhancing catalytic activity and promoting uniform polyolefin powder morphology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a metallocene catalyst is used in olefin polymerization, then olefin polymerization activity is improved, but polyolefin powder morphology uniformity deteriorates
Solution Approach 1:
The patent applies local quality by creating distinct zones within the catalyst structure: aluminum alkyl halide is supported on the outer surface while cocatalyst is supported inside the pores. This spatial differentiation of catalyst components creates localized functional zones that control polymerization at different locations, resulting in uniform polyolefin powder morphology while maintaining high polymerization activity.
Solution Approach 2:
The patent segments the catalyst support structure into two distinct regions: surface-supported aluminum alkyl halide and pore-supported cocatalyst. This segmentation allows independent optimization of each component's function and prevents the formation of non-uniform particle shapes that would occur with homogeneous catalyst distribution.
2Productivity
If non-uniform polyolefin particle shape is obtained, then polymerization productivity is improved, but reactor fouling increases
Solution Approach 1:
The patent applies preliminary anti-action by pre-forming uniform spherical polyolefin particles through controlled catalyst structure design before polymerization. The uniform morphology prevents particle collision and aggregation that would generate fines and cause reactor fouling, thereby maintaining high productivity without the harmful effects of non-uniform particle shapes.
3Power
If aluminum alkyl halide is supported uniformly throughout the carrier, then catalytic activity is improved, but polyolefin powder morphology uniformity deteriorates
Solution Approach 1:
The patent implements local quality by positioning aluminum alkyl halide specifically on the outer surface of the silica-based carrier rather than uniformly throughout. This localized placement, combined with cocatalyst inside the pores, creates a controlled gradient of catalytic activity that maintains overall catalytic efficiency while ensuring uniform polyolefin powder morphology.
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 supported metallocene catalyst achieves high olefin polymerization activity while producing polyolefin with a uniform powder morphology, reducing fines generation and reactor fouling, thereby improving process stability and efficiency.
Implementation Method 1
supporting aluminum alkyl halide in a silica-based carrier
Implementation Method 2
supporting a cocatalyst compound in the silica-based carrier in which the aluminum alkyl halide is supported
Implementation Method 3
polymerizing olefin monomers in the presence of the supported metallocene catalyst to obtain polyolefin
Data Source
AI summary
A supported metallocene catalyst can include a silica-based carrier and an aluminum alkyl halide, a cocatalyst compound, and a metallocene compound supported in the silica-based carrier. The aluminum alkyl halide is supported at higher rate on the surface of the silica-based carrier than inside the pores, and the cocatalyst compound is supported at higher rate inside the pores of the silica-based carrier than on the surface of the silica-based carrier. Such a supported metallocene catalyst can be prepared by: (i) supporting an aluminum alkyl halide in a silica-based carrier; (ii) supporting a cocatalyst compound in the silica-based carrier in which the aluminum alkyl halide is supported; and (iii) supporting a metallocene compound in the carrier in which the aluminum alkyl halide and the cocatalyst compound are supported. Such a supported metallocene catalyst can be used to polymerize polyolefins with excellent activity and polyolefin with a uniform powder morphology.