Multimodal Polyethylene Reactor With Hydrogen Removal Unit
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Solution Overview
Problem
Current multimodal polyethylene polymerization processes face challenges in achieving improved mechanical properties, such as Charpy impact strength, and efficient hydrogen removal, leading to increased raw material consumption and process inefficiencies.
Innovation Solution
A reactor system comprising a first reactor, a hydrogen removal unit, and a second and third reactor, where 98.0 to 99.8% of hydrogen is removed from the slurry mixture before transferring it to the second reactor, allowing for the production of high molecular weight polyethylene with enhanced mechanical properties and a multimodal polyethylene composition suitable for blow molding and thermoforming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If hydrogen is not removed from the first reactor before transferring slurry to the second reactor, then the polymerization process is simpler and faster, but the molecular weight control and mechanical properties of the final polyethylene are compromised
Solution Approach 1:
The patent divides the polymerization process into multiple reactors (first reactor for low molecular weight fraction, second reactor for high molecular weight fraction) with a hydrogen removal unit in between. This segmentation allows each reactor to be optimized for specific molecular weight production while removing hydrogen between stages to prevent interference with the second reactor's polymerization, thereby achieving both mechanical property improvement and process feasibility.
Solution Approach 2:
The patent extracts hydrogen from the slurry mixture between the first and second reactors using a hydrogen removal unit. This extraction removes the harmful factor (hydrogen) that would otherwise interfere with the high molecular weight polymerization in the second reactor, enabling the production of polyethylene with improved mechanical properties without excessive process complexity.
2Strength
If hydrogen removal is performed using conventional methods, then the process is simpler, but hydrogen consumption increases and mechanical properties deteriorate
Solution Approach 1:
The patent changes the operating parameters of the hydrogen removal unit, specifically operating at a pressure of 100-200 kPa (abs) which is lower than conventional operating pressures. This parameter change enables more efficient hydrogen removal (98.0-99.8% hydrogen removal efficiency) while reducing hydrogen consumption and improving the mechanical properties of the final polyethylene product.
3Strength
If high molecular weight polyethylene is produced in the second reactor without efficient hydrogen removal, then the process is faster, but the mechanical properties and swelling ratio are compromised
Solution Approach 1:
The patent optimizes the operating pressure of the hydrogen removal unit to 100-200 kPa (abs), which balances hydrogen removal efficiency with production efficiency. This parameter optimization achieves 98.0-99.8% hydrogen removal while maintaining high production efficiency, enabling the second reactor to produce high molecular weight polyethylene with improved mechanical strength and swelling ratio without excessive process delays.
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 results in polyethylene compositions with superior mechanical strength, swelling ratio, and balanced mechanical properties and processing behavior, enabling the production of containers with improved impact resistance and stiffness, while reducing hydrogen consumption and operational costs.
Implementation Method 1
a hydrogen removal unit arranged between the first reactor and a second reactor, the hydrogen removal unit comprising at least one vessel connected with a depressurization equipment
Data Source
AI summary
The present invention relates to a reactor system for a multimodal polyethylene polymerization process, comprising; (a) a first reactor; (b) a hydrogen removal unit arranged between the first reactor and a second reactor comprising at least one vessel connected with a depressurization equipment, preferably selected from vacuum pump, compressor, blower, ejector or a combination thereof, the depressurization equipment allowing to adjust an operating pressure to a pressure in a range of 100-200 kPa (abs); (c) the second reactor; and (d) a third reactor and the use thereof as a container.