Rotating Hollow Body Gas-Solid Separator for Polymerization

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Solution Overview

Problem

Existing methods for gas-solid separation in olefin polymerization processes, such as those described in EP 1 080 116 B1 and US 7,098,301 B1, face issues with the buildup of fine polymer particles in equipment, leading to reduced efficiency and potential equipment failure, and require costly purging systems to maintain operation.

Innovation Solution

A rotating hollow body with elongated rectangular blades and a cylindrical baffle is used to separate solid particles from a mixed phase solids-gas stream, allowing the gas stream to pass through while preventing solid particles from entering the interior, effectively removing fines without the need for frequent maintenance or increased operating costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a cyclone is used to separate solid polymer particles from vapor stream, then separation of bulk solids is achieved, but fine particles (fines) are not effectively removed and build up in equipment

Engineering Contradiction:
Improveseparation efficiencyVSAvoidfine particle buildup
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

A bag filter is introduced as an intermediary component between the cyclone separator and the heat exchanger. The bag filter acts as a mediator that captures fine particles which the cyclone cannot remove, preventing their buildup in downstream equipment while maintaining the cyclone's bulk separation function.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

A flexible bag filter with a porous membrane is used to separate fine particles from the vapor stream. The thin film structure of the bag filter allows vapor to pass through while capturing fine particles, providing effective filtration without significant pressure drop.

Inventive Principle:
Principle #30Flexible shells and thin films

2Object-affected harmful factors

If bag filters are used to remove fine particles, then fine particle removal is achieved, but filters require frequent cleaning and replacement increasing operating costs

Engineering Contradiction:
Improvefine particle buildupVSAvoidfilter maintenance system
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The bag filter is designed to be periodically replaced rather than continuously cleaned. The filter bags are easily removable and can be quickly replaced during scheduled maintenance intervals, minimizing operational disruption and reducing the complexity of continuous cleaning systems.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The bag filter uses inexpensive, disposable filter bags that can be quickly replaced rather than expensive, durable filters requiring complex cleaning mechanisms. The low cost of the filter bags makes frequent replacement economically viable.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If purging systems are installed to prevent fine particle buildup, then equipment operability is maintained, but operating costs increase significantly

Engineering Contradiction:
Improveequipment operabilityVSAvoidpurging system operating cost
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The harmful fine particles are extracted from the vapor stream using the bag filter before they can cause buildup in equipment. This preventive extraction eliminates the need for expensive purging systems that would be required to remove particles after they have deposited in equipment.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The bag filter converts the harmful effect of fine particles (which would cause buildup and require purging) into a beneficial separation process. By capturing fines early, the system prevents the need for energy-intensive purging operations downstream.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 method efficiently removes fine particles from the gas phase, reducing equipment buildup and operational costs, and maintains high separation efficiency without the need for filter cleaning or replacement, ensuring continuous operation in olefin polymerization processes.

Implementation Method 1

a rotating hollow body provided with a plurality of openings and a plurality of elements exposing a surface to said solids-gas stream during rotation of said hollow body

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Data Source

PatentEP2225015B1Method and apparatus for gas-solid separation, application to polymerization reactions
Publication Date: 2018.12.19 BASELL POLIOLEFINE ITALIA SRL
  • EP2225015B1 patent drawingFigure 1
  • EP2225015B1 patent drawingFigure 2
  • EP2225015B1 patent drawingFigure 3

AI summary

Method and apparatus for the gas-solid separation comprising a separation chamber provided with a rotating hollow body, mounted at the top wall of said separation chamber. The rotating hollow body comprises a plurality of spaced-apart blades defining openings for the passage of gas, but rejecting solid particles entrained by the gas. The apparatus comprises also a cylindrical baffle surrounding the rotating hollow body to further deviate a mixed-phase gas-solids stream entering the separation chamber, and to promote settling of solid particles. The gas-solid separation method can be used to separate a gas-polymer mixture produced in a polymerization process.