Polyethylene-Diene Copolymer Feed Segmentation
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Solution Overview
Problem
The existing high-pressure process for manufacturing polyethylene-diene-copolymers faces inefficiencies due to pre-polymerization of ethylene and diene comonomers in the preheater unit, leading to reduced output and increased initiator requirements, as well as contamination risks and fouling in the process equipment.
Innovation Solution
A method where ethylene and diene comonomer are fed separately to the compressor and preheater units, and only combined before entering the reactor, allowing for controlled introduction of chain transfer agents and initiators, creating distinct reaction zones within the reactor to optimize polymerization conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ethylene and diene comonomer are fed together to the compressor unit and preheater, then the polymerization reaction can proceed, but the output of copolymer is reduced and initiator feed must be increased
Solution Approach 1:
The patent divides the feed streams into separate paths: ethylene is fed through the compressor and preheater, while diene comonomer is fed separately and combined with ethylene only after the preheater. This segmentation prevents premature interaction between the comonomer and heat, eliminating prepolymerization and associated harmful effects.
Solution Approach 2:
The patent performs preliminary heating of ethylene alone before combining it with the diene comonomer. This preliminary action ensures that ethylene reaches the required temperature for polymerization without causing unwanted prepolymerization of the comonomer mixture, thereby maintaining copolymer output and initiator levels.
2Temperature
If ethylene and diene comonomer are preheated together, then the feed can enter the reactor, but the preheater exit temperature is lower than expected due to prepolymerization
Solution Approach 1:
The heating process is segmented into two stages: first, ethylene is preheated alone to the required temperature; second, the heated ethylene is combined with the diene comonomer. This prevents the comonomer from undergoing prepolymerization during heating, maintaining both temperature and process efficiency.
Solution Approach 2:
The patent uses heated ethylene as an intermediary carrier that transfers thermal energy to the diene comonomer after mixing. This indirect heating approach avoids direct thermal exposure of the comonomer mixture, preventing prepolymerization while achieving the necessary reaction temperature.
3Ease of operation
If diene comonomer is fed to the compressor and preheater, then it can be mixed with ethylene, but contamination and fouling of process equipment occurs
Solution Approach 1:
The patent segments the feed system so that the diene comonomer bypasses the compressor and preheater units, being fed separately and combined with ethylene only after these units. This physical separation prevents the comonomer from causing contamination and fouling in sensitive equipment while still enabling thorough mixing before reactor entry.
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 increases the output of ethylene-diene-copolymer, maintains initiator levels similar to homopolymer synthesis, reduces contamination risks, and enhances process efficiency by avoiding pre-mixing and preheating issues, thereby improving the overall production process.
Implementation Method 1
a first feed stream comprising ethylene is fed into at least one compressor unit
Implementation Method 2
subsequently into at least one preheater unit
Implementation Method 3
The exothermic polymerization reaction is carried out under operating pressures between 500 and 4000 bar and temperatures between 165 to 340°C
Implementation Method 4
The polymerization of ethylene is started by free radical initiator, usually using peroxides or oxygen
Data Source
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AI summary
The present invention provides a process for manufacturing polyethylene-diene-copolymer conducted in a plant comprising at least one compressor unit (10), at least one preheater unit (20) being downstream of the compressor unit (10) and at least one reactor (30), in particular a reactor, being downstream of the compressor unit (10) and the preheater unit (20) a) Feeding a first feed stream (1) comprising ethylene into the at least one compressor unit (10) and subsequently into the at least one preheater unit (20), b1) Feeding a second feed stream (2) comprising at least one diene comonomer to the first feed stream (1) leaving the at least preheater unit (20), and feeding the combined feed streams (4) comprising ethylene and the at least one diene comonomer to the at least one reactor (30), and/or b2) Feeding a second feed stream (2) comprising at least one diene comonomer to the at least one reactor (30) at at least one location along the reactor (30).