Polymerization Reactor Segmentation for High Solids Mixing

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Solution Overview

Problem

Conventional polymerization processes using diluents result in high viscosity slurries that hinder mixing and heat transfer, impact polymer properties, and are energy-intensive, with limitations on solids content and costly solvent removal processes.

Innovation Solution

A reactor design with distinct zones for mixing, separation, and compaction, featuring a shaft assembly with paddles and hooks for kneading, helical flights for separation, and a compaction zone to reduce voids and drive out diluents, facilitating efficient polymerization and deliquification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional polymerization processes use diluents to facilitate heat transfer, then heat transfer is improved, but the slurry viscosity becomes high which hinders mixing and heat transfer

Engineering Contradiction:
Improveheat transferVSAvoidmixing
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The reactor is divided into three distinct zones: a reaction zone for polymerization, a separation zone for separating polymer from diluent, and a compaction zone for removing excess diluent. This segmentation allows each zone to optimize its specific function, with the reaction zone maintaining high solids content for efficient heat transfer while the separation and compaction zones handle the diluent removal, resolving the contradiction between heat transfer efficiency and mixing ease.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If conventional processes use adequate volumes of diluent to maintain fluid conditions, then mixing is improved, but the solids content of polymer produced is limited

Engineering Contradiction:
ImprovemixingVSAvoidsolids content
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

By segmenting the reactor into reaction, separation, and compaction zones, the system can maintain high solids content in the reaction zone without compromising mixing. The separation zone then removes the diluent, allowing high polymer yield while maintaining operational fluidity during the reaction phase.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The separation and compaction zones perform diluent removal actions during the polymerization process itself, rather than requiring post-reaction solvent stripping. This preliminary action allows the reaction to proceed at high solids content with adequate mixing, then removes excess diluent before the polymer is discharged.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If conventional processes conduct polymerization in the presence of diluent, then polymerization is facilitated, but solvent removal requires energy-intensive processes

Engineering Contradiction:
Improvepolymerization processVSAvoidenergy consumption
Core Design Contradiction:
Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The reactor segments the polymerization process into zones where diluent is progressively removed. The separation zone uses gravity and centrifugal forces for diluent separation, and the compaction zone uses mechanical pressure for further diluent removal. This eliminates or reduces the need for energy-intensive post-reaction solvent stripping processes while maintaining polymerization efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The reactor system performs its own deliquification through the integrated separation and compaction zones, removing diluent during the polymerization process itself. This self-service approach eliminates the need for separate, energy-intensive solvent removal operations that would otherwise be required.

Inventive Principle:
Principle #25Self-service

4Ease of operation

If conventional processes use continuously-stirred tank reactors with adequate diluent volumes, then reactor operability is maintained, but the process is costly and energy-intensive

Engineering Contradiction:
Improvereactor operabilityVSAvoidprocess cost
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The reactor is segmented into three functional zones within a single vessel, combining reaction, separation, and compaction functions. This integrated design maintains reactor operability throughout the polymerization process while eliminating the need for separate solvent removal equipment and processes, thereby reducing overall device complexity and process cost.

Inventive Principle:
Principle #1Segmentation

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 efficient polymerization at high solids content, improves mixing and heat transfer, reduces energy consumption, and simplifies the deliquification process, enhancing polymer properties and reactor operability.

Implementation Method 1

a shaft assembly with paddles and hooks for kneading

Methodology Applied
Scientific EffectMechanical mixing: Stirring

Implementation Method 2

helical flights for separation

Methodology Applied
Scientific EffectGravitational separation: Gravitation

Implementation Method 3

helical flights for separation

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Implementation Method 4

a compaction zone to reduce voids and drive out diluents

Methodology Applied
Scientific EffectMechanical compression: Compression

Implementation Method 5

the diluent facilitates heat transfer away from the polymer agglomerates

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 6

the diluent facilitates heat transfer away from the polymer agglomerates

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3212320B1Reactor and process for multi-phase composition
Publication Date: 2021.05.05 EXXONMOBIL CHEMICAL PATENTS INC
  • EP3212320B1 patent drawingFigure 1
  • EP3212320B1 patent drawingFigure 2~2A
  • EP3212320B1 patent drawingFigure 3~3A

AI summary

A reactor (20) comprising a first portion (30) having a generally cylindrical housing (40), an inlet at one end of said first portion housing, the opposed end of said first portion housing being the outlet of said first portion, where said first portion includes a rotatable shaft (24) positioned axially within said housing (40) and including at least two shearing paddles (62) extending radially from said rotatable shaft (24) and a second portion (32) having a generally frustoconical housing (70) having a first end larger than a second end, said first end constituting an inlet to said second portion and coextensive with said opposed end of said first portion housing (40), and an outlet at said second end, where said second portion includes a rotatable shaft (24) positioned axially within said housing and including at least one generally helical flight (20) extending radially from said rotatable shaft (24).