Ethylene Oligomerization Solvent Recycling Eliminates Compressors

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Solution Overview

Problem

The conventional method for recycling unreacted ethylene in oligomerization reactions is economically infeasible due to the need for low-temperature refrigerants and separate compressors, leading to high investment costs.

Innovation Solution

A method where unreacted ethylene is dissolved in a solvent and reintroduced to the reactor, eliminating the need for low-temperature refrigerants and separate compressors by using a pump to increase pressure, thereby reducing costs and improving economic feasibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If unreacted ethylene is recovered as gas phase and pressure is increased using a compressor, then the ethylene can be reused in the reactor, but investment costs increase due to separate compressor installation

Engineering Contradiction:
Improveethylene reuse capabilityVSAvoidcompressor installation
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a solvent as an intermediary medium to dissolve and transport unreacted ethylene from the separation device back to the reactor. This solvent-mediated transport eliminates the need for direct compression of gaseous ethylene, thereby avoiding the installation of separate compressors while maintaining effective ethylene recycling.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stress or pressure

If unreacted ethylene stream is cooled to liquid phase using refrigerant at very low temperature, then pressure can be increased using a pump, but investment costs increase due to refrigerant requirements

Engineering Contradiction:
Improveethylene stream pressureVSAvoidrefrigerant temperature
Core Design Contradiction:
Stress or pressureVSTemperature

Solution Approach 1:

The patent changes the physical state parameters of ethylene by dissolving it in a solvent at moderate temperatures, avoiding the need for extreme cooling to liquid phase. This parameter change allows pressure increase via pump without requiring refrigerants at very low temperatures, reducing investment costs.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If unreacted ethylene is dissolved in solvent and supplied as liquid stream, then investment costs are reduced by eliminating refrigerants and compressors, but the dissolution process must be efficient

Engineering Contradiction:
Improveequipment requirementsVSAvoidethylene dissolution rate
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent uses a solvent that effectively copies or mimics the transport function previously performed by compression equipment. The solvent creates a liquid-phase carrier system that replicates the ethylene delivery function, eliminating mechanical compression while maintaining productivity through efficient dissolution and transport.

Inventive Principle:
Principle #26Copying

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 efficient recycling of ethylene without the need for refrigerants or additional compressors, simplifying the process and reducing costs while maintaining high dissolution rates of ethylene, thus improving oligomer production efficiency.

Implementation Method 1

supplying the upper discharge stream including the monomer from the second separation device to a monomer dissolution device to dissolve the upper discharge stream in a solvent supplied to the monomer dissolution device

Methodology Applied
Scientific EffectDissolution: Absorption (physical)

Data Source

PatentEP3984985B1Process for producing oligomers and apparatus for producing oligomers
Publication Date: 2024.10.02 LG CHEM LTD
  • EP3984985B1 patent drawingFigure 1~2
  • EP3984985B1 patent drawingFigure 3~4
  • EP3984985B1 patent drawing

AI summary

Provided are a method for preparing an oligomer including: supplying a feed stream including a monomer to a reactor and performing an oligomerization reaction; supplying a first discharge stream from the reactor to a first separation device and supplying a second discharge stream from the reactor to a second separation device; recovering the monomer in the second separation device as an upper discharge stream; supplying the upper discharge stream including the monomer from the second separation device to a monomer dissolution device to dissolve the upper discharge stream in a solvent supplied to the monomer dissolution device; and supplying a discharge stream from the monomer dissolution device to the reactor, and an apparatus for preparing oligomer.