Chain Transfer Agent Supply Line for Low-Pressure Polyethylene
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Solution Overview
Problem
Existing high-pressure polyethylene manufacturing methods face inefficiencies in handling chain transfer agents, including variations in concentration and increased compression energy, which complicates the polymerization process.
Innovation Solution
The proposed solution involves a simplified apparatus and method where a chain transfer agent supply line is connected to a low-pressure recycle ethylene supply line, controlling pressure and temperature to reduce concentration deviations and compression energy, incorporating a chain transfer agent supply line connected to a low-pressure recycle ethylene line, and utilizing a multi-stage compression system to efficiently manage ethylene and propane as the chain transfer agent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a chain transfer agent is supplied through a high-pressure system, then the polymerization process can be maintained, but the apparatus complexity and compression energy increase
Solution Approach 1:
The patent introduces a low-pressure recycle ethylene supply line as an intermediary pathway for chain transfer agent delivery. Instead of directly injecting CTA into the high-pressure polymerization system, the CTA is first mixed with recycle ethylene at low pressure, then the mixture is compressed together. This intermediary approach simplifies the CTA supply apparatus while maintaining process reliability.
Solution Approach 2:
The patent merges the CTA supply function with the existing low-pressure recycle ethylene supply system. By combining CTA injection with the recycle ethylene flow path, the invention eliminates the need for separate high-pressure CTA injection equipment, thereby reducing apparatus complexity while ensuring reliable polymerization through proven high-pressure compression infrastructure.
2Reliability
If a chain transfer agent is supplied through a high-pressure system, then the polymerization process can be maintained, but the compression energy increases
Solution Approach 1:
The low-pressure recycle ethylene acts as an intermediary carrier for the chain transfer agent. By mixing CTA with recycle ethylene at low pressure before compression, the system avoids the energy-intensive task of compressing pure CTA to high pressure. The compressor only needs to handle the CTA-ethylene mixture at the existing recycle pressure level, significantly reducing compression energy requirements.
Solution Approach 2:
The patent changes the pressure parameter at which CTA is introduced into the system. Instead of maintaining CTA at high pressure throughout the supply line, the CTA is introduced at low pressure and only compressed when mixed with recycle ethylene. This parameter change from high-pressure CTA supply to low-pressure CTA supply with subsequent mixture compression reduces the overall compression energy consumption.
3Ease of operation
If the chain transfer agent concentration is not controlled, then the supply process is simpler, but the concentration deviation increases
Solution Approach 1:
The patent implements a feedback control mechanism where the CTA supply rate is adjusted based on the measured concentration in the polymerization system. The control unit continuously monitors CTA concentration and modifies the CTA injection rate accordingly, ensuring stable concentration control while maintaining operational simplicity through automated adjustment rather than manual intervention.
Solution Approach 2:
The low-pressure recycle ethylene supply line serves multiple functions: it acts as the carrier gas for CTA transport, provides a controlled flow path for precise CTA dosing, and serves as the medium through which CTA concentration can be uniformly distributed and monitored. This multi-functionality enables both simple operation and precise concentration control through a single integrated system.
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 allows for more efficient supply of chain transfer agents with reduced concentration variations and lower compression energy, enhancing the production of high-pressure low-density polyethylene suitable for various industrial applications.
Implementation Method 1
a compressor (1) that compresses ethylene
Implementation Method 2
a reactor (4) that polymerizes ethylene using ethylene supplied from the secondary compressor (3) and a polymerization initiator supplied to the reactor (4) to manufacture polyethylene
Implementation Method 3
a high-pressure separator (5) that separates polyethylene obtained in the reactor (4) and recycle ethylene from each other
Implementation Method 4
a low-pressure separator (8) that separates low-pressure recycle ethylene contained in polyethylene separated by the high-pressure separator (5) and supplied through the polyethylene discharge line (7) from the polyethylene
Data Source
AI summary
Provided are an apparatus and a method for manufacturing high-pressure method low-density polyethylene, the apparatus and the method having excellent characteristics that a chain transfer agent can be supplied by a simpler apparatus, a deviation (variation) of the concentration of the chain transfer agent supplied to a reactor can be reduced, and compression energy of the chain transfer agent can be reduced. An apparatus for manufacturing high-pressure method polyethylene includes a chain transfer agent supply line that is a line connected to a low pressure recycle ethylene supply line for supplying a chain transfer agent.