Polymer Separator Switching LCST and Flash Modes

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Solution Overview

Problem

Current continuous solution polymerization processes struggle to achieve clean separation of low molecular weight polymers from solvents, leading to polymer carry-over and equipment fouling, requiring different separation systems for high and low molecular weight polymers.

Innovation Solution

A flexible process and apparatus that uses sequential heat exchanger systems to adjust effluent temperatures and pressures, allowing for the production of both high and low molecular weight polymers in the same plant, utilizing LCST or flash vaporization methods depending on the polymer type, ensuring effective separation and recycling of solvents and unreacted monomers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If LCST separation is used for low molecular weight polymers, then the separation process is energy efficient, but polymer carry-over occurs and equipment fouling results

Engineering Contradiction:
Improveenergy efficiencyVSAvoidpolymer carry-over and equipment fouling
Core Design Contradiction:
Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by adjusting temperature and pressure conditions to control the phase behavior of polymer-solvent systems. By operating at temperatures above the LCST and maintaining high pressures, the system prevents vaporization while achieving clean phase separation. This resolves the contradiction by modifying operational parameters to eliminate polymer carry-over while preserving the energy efficiency of LCST separation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs dynamic control of separation conditions, allowing the system to adapt between LCST separation and flash vaporization modes based on polymer molecular weight. For low molecular weight polymers, the system dynamically adjusts to prevent carry-over while maintaining energy efficiency, thus resolving the contradiction between energy efficiency and preventing harmful effects.

Inventive Principle:
Principle #15Dynamics

2Object-generated harmful factors

If flash vaporization is used for low molecular weight polymers, then polymer carry-over is prevented, but energy consumption increases and the system cannot process high molecular weight polymers efficiently

Engineering Contradiction:
Improvepolymer carry-over preventionVSAvoidenergy consumption
Core Design Contradiction:
Object-generated harmful factorsVSLoss of energy

Solution Approach 1:

The patent implements a universal separation system that can handle both low and high molecular weight polymers using the same apparatus. By integrating both LCST separation and flash vaporization capabilities into one system, it achieves polymer carry-over prevention for low molecular weight polymers while maintaining energy efficiency for high molecular weight polymers, thus resolving the contradiction between preventing harmful effects and energy consumption.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses parameter changes to switch between separation modes. For low molecular weight polymers, flash vaporization parameters are applied to prevent carry-over. For high molecular weight polymers, LCST separation parameters are used to minimize energy consumption. This dynamic parameter adjustment resolves the contradiction by applying the appropriate method based on polymer characteristics.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If different separation systems are used for high and low molecular weight polymers, then each polymer type can be processed optimally, but device complexity and plant configuration requirements increase

Engineering Contradiction:
Improveprocessing optimizationVSAvoidseparation system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a single multi-functional separation system that can process both high and low molecular weight polymers. The system incorporates both LCST separation and flash vaporization capabilities within one apparatus, eliminating the need for separate processing lines. This resolves the contradiction by maintaining processing optimization while reducing device complexity and plant configuration requirements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The separation system is designed to be dynamic and adaptable, allowing it to switch between LCST separation and flash vaporization modes based on the polymer type being processed. This dynamic capability enables one system to perform the functions of multiple specialized systems, resolving the contradiction between processing optimization and device complexity.

Inventive Principle:
Principle #15Dynamics

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

Enables the recovery of both high and low molecular weight polymers in the same apparatus without polymer carry-over in the solvent recycle stream, improving process efficiency and reducing equipment fouling, while allowing for the reuse of solvents and unreacted monomers.

Implementation Method 1

the first product effluent is heated by heat transfer from the first polymer-lean liquid phase in at least one primary heat exchanger and from an external source of heat in at least one secondary heat exchanger

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

reducing the pressure to a point where two phases (polymer-rich phase and polymer-lean phase) are formed... heating the product mixture under high pressure, followed by reducing the pressure to a point where two phases (polymer-rich phase and polymer-lean phase) are formed

Methodology Applied
Scientific EffectLCST phase separation: Phase Change

Implementation Method 3

The denser polymer-rich phase settles to the bottom of the vessel where it is pressure fed to downstream equipment

Methodology Applied
Scientific EffectDensity-based settling: Gravitation

Implementation Method 4

recovery of low molecular weight polymers is generally achieved by flash vaporization of the solvent. Flash vaporization prevents the low-molecular weight polymer from being carried over in the vapor stream

Methodology Applied
Scientific EffectFlash vaporization: Evaporation

Data Source

PatentEP2825570B1Processes and apparatus for continuous solution polymerization
Publication Date: 2020.04.15 EXXONMOBIL CHEMICAL PATENTS INC
  • EP2825570B1 patent drawingFigure 1
  • EP2825570B1 patent drawingFigure 2

AI summary

This invention relates to a blocked process for producing polymers of high and low molecular weights utilizing the same polymer separator. The separator is operated in a different mode depending on the molecular weight of the polymer being produced such that the separation system is operated in flash mode for the separation of low molecular weight polymers and operated in lower critical solution temperature (LCST) mode for the separation of high molecular weight polymers.