Loop and Fluidized Bed Reactor Series for Multimodal Ethylene Polymerization
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Solution Overview
Problem
Current methods for producing multimodal ethylene polymers lack efficiency in achieving desired molecular weight distributions and end-use applications, as existing reactor systems struggle to consistently produce polymers with tailored properties for film, pipe, and blow molding applications.
Innovation Solution
The use of a combination of loop reactors and fluidized bed reactors, configured in series or parallel, where ethylene polymers are produced under slurry or supercritical conditions, with catalyst compositions and olefin comonomers, allowing for controlled molecular weight distribution through hydrogen management and comonomer addition in different polymerization phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single reactor system is used for ethylene polymerization, then the process is simple to operate, but the molecular weight distribution cannot be effectively tailored for multimodal polymers
Solution Approach 1:
The patent divides the polymerization process into multiple reactor stages (loop reactor for high molecular weight component, fluidized bed reactor for low molecular weight component) to produce multimodal polymers with tailored molecular weight distributions. Each reactor operates under different conditions to generate specific polymer fractions that are then combined.
Solution Approach 2:
The patent combines the outputs from multiple reactor systems (loop reactor effluent and fluidized bed reactor effluent) to produce a multimodal polymer with composite molecular weight characteristics. This merging allows the final product to exhibit properties from both high and low molecular weight components.
2Adaptability or versatility
If multiple reactor systems are used in series or parallel, then multimodal polymers with tailored properties can be produced, but the process complexity increases
Solution Approach 1:
The patent employs a multi-reactor system where each reactor performs a specific function (loop reactor for high MW, fluidized bed for low MW) but together they serve the universal purpose of producing multimodal polymers suitable for various end-use applications including film, pipe, and blow molding.
Solution Approach 2:
Different regions of the polymerization process (different reactors) are optimized for different local qualities: the loop reactor produces high molecular weight polymer with specific rheological properties, while the fluidized bed reactor produces low molecular weight polymer with different characteristics, and these are combined to achieve the desired overall polymer properties.
3Manufacturing precision
If hydrogen is used to control molecular weight, then polymerization control is improved, but hydrogen separation and management becomes more complex
Solution Approach 1:
The patent extracts and separates hydrogen from the reactor effluent streams to manage its role in molecular weight control. By removing hydrogen through separation units, the process can precisely control the molecular weight of polymer produced in each reactor while managing hydrogen as a distinct stream for recycling or disposal.
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 enables the production of multimodal ethylene polymers with tailored molecular weight distributions, enhancing their suitability for various end-use applications such as film, pipe, and blow molding by controlling molecular weight and rheological properties.
Implementation Method 1
contacting a catalyst composition with ethylene, an optional first olefin comonomer, and hydrogen in an inert hydrocarbon diluent in a loop reactor under slurry or supercritical polymerization conditions to produce a first ethylene polymer
Implementation Method 2
contacting a catalyst composition with ethylene, an optional first olefin comonomer, and hydrogen in an inert hydrocarbon diluent in a loop reactor under slurry or supercritical polymerization conditions to produce a first ethylene polymer
Implementation Method 3
contacting the intermediate material with ethylene and an optional second olefin comonomer in an inert gas and/or hydrocarbon in a fluidized bed reactor under gas phase polymerization conditions to produce the multimodal ethylene polymer
Implementation Method 4
separating a light fraction comprising hydrogen from the first reactor effluent to form an intermediate material
Data Source
AI summary
Polymerization processes and reactor systems for producing multimodal ethylene polymers are disclosed in which at least one loop reactor and at least one fluidized bed reactor are utilized. Configurations include a loop reactor in series with a fluidized bed reactor and two loop reactors in series with a fluidized bed reactor.