Cyclone Separator for Ethylene Oligomerization Recycle Loop

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Solution Overview

Problem

Polymer fouling in the ethylene recycle loop of oligomerization reactors leads to reactor shutdowns and costly cleaning processes, necessitating an effective solution to prevent or reduce fouling.

Innovation Solution

The implementation of a cyclone separator upstream of heat exchangers in the ethylene recycle loop to separate entrained liquid droplets from gaseous ethylene, thereby preventing polymer fouling of downstream equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the overhead ethylene stream is cooled in heat exchangers, then the ethylene is condensed and prepared for recycling, but polymeric material entrained in the gaseous ethylene fouls the heat exchanger equipment

Engineering Contradiction:
Improveethylene stream temperatureVSAvoidpolymer fouling of heat exchangers
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The cyclone separator extracts and removes polymeric material from the gaseous ethylene stream before the stream enters the heat exchangers. This separation prevents the polymeric material from contacting and fouling the heat exchanger surfaces, allowing the cooling function to proceed without contamination.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The cyclone separator performs a preliminary separation action upstream of the heat exchangers, removing polymeric material before the ethylene stream undergoes cooling. This preliminary removal prevents subsequent fouling issues that would otherwise occur during the heat exchange process.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the reactor operates continuously to maintain production, then productivity is improved, but polymer fouling eventually requires shutdown for cleaning

Engineering Contradiction:
Improvereactor production continuityVSAvoidreactor operation stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The cyclone separator continuously extracts polymeric material from the recycle loop, preventing accumulation that would lead to fouling and shutdowns. This continuous removal mechanism allows the reactor to maintain uninterrupted operation while preserving system reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The cyclone separator enables continuous operation by maintaining a constant separation function that prevents fouling buildup. The system maintains continuous production without interruption because the polymeric material is continuously removed before it can cause shutdown-requiring fouling.

Inventive Principle:
Principle #20Continuity of useful action

3Object-affected harmful factors

If a cyclone separator is added to the ethylene recycle loop, then polymer fouling is prevented, but device complexity increases

Engineering Contradiction:
Improvepolymer foulingVSAvoidrecycle loop equipment
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The cyclone separator acts as an intermediary device between the reactor overhead and the heat exchangers. It mediates the ethylene stream by removing polymeric material, protecting downstream equipment without requiring complex modification of existing components.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The cyclone separator replaces the need for complex chemical cleaning systems and frequent manual maintenance. By using simple centrifugal separation mechanics, it prevents fouling without requiring sophisticated control systems or complex mechanical cleaning mechanisms.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical 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

The use of a cyclone separator significantly reduces polymer fouling, minimizing reactor downtime, reducing the need for cleaning chemicals, and lowering fouling rates during production.

Implementation Method 1

introducing a gaseous ethylene stream comprising entrained liquid into a cyclone separator; withdrawing a gaseous product stream comprising ethylene from the cyclone separator; withdrawing a liquid product stream comprising at least one linear alpha olefin and/or polymeric material from the cyclone separator

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Data Source

PatentEP4552723A1System and methof for treating gaseous ethylene from oligomerization reactor
Publication Date: 2025.05.14 SABIC GLOBAL TECHNOLOGIES BV
  • EP4552723A1 patent drawingFigure 1
  • EP4552723A1 patent drawingFigure 2
  • EP4552723A1 patent drawingFigure 3

AI summary

The disclosure provides a method for separating entrained liquid from gaseous ethylene leaving an ethylene oligomerization reactor, the method including introducing a gaseous ethylene stream comprising entrained liquid into a cyclone separator; withdrawing a top product stream including gaseous ethylene from the cyclone separator; withdrawing a liquid bottom product stream including at least one linear alpha olefin and/or polymeric material from the cyclone separator, the liquid bottom product stream optionally combined with a linear alpha olefin product stream from the ethylene oligomerization reactor; and passing the top product stream including gaseous ethylene through one or more heat exchangers to form a cooled gaseous ethylene stream, which is optionally recycled to the ethylene oligomerization reactor.