Gas Permeation Membrane Cleaning via Reverse Flow

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Solution Overview

Problem

Gas permeation membranes in separation units are often clogged by long-chain hydrocarbons and other impurities, leading to reduced performance and making complete regeneration difficult, especially when traditional cleaning methods push contaminants deeper into the selective layer.

Innovation Solution

A method involving the introduction of a suitable gas or gas mixture, such as hot air, against the operating direction of the membrane, with gradual temperature increase between 50°C and 150°C, and optional overpressure, using only two outlets/inlets to prevent re-deposition of contaminants and effectively clean the selective layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional cleaning methods are used to remove impurities from the membrane, then some contaminants are removed, but the contaminants are pushed deeper into the selective layer making complete regeneration difficult

Engineering Contradiction:
Improvemembrane performanceVSAvoidregeneration difficulty
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The patent applies reverse flow cleaning where the cleaning gas is introduced through the permeate side and flows in the opposite direction to the normal operating flow. This inversion prevents contaminants from being pushed deeper into the selective layer and enables effective removal without damaging the membrane structure.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent utilizes temperature increase (thermal treatment) as a parameter change to facilitate contaminant removal. By gradually increasing the temperature of the cleaning gas, the method enables effective desorption and removal of hydrocarbon contaminants from the membrane pores and selective layer.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the membrane units are disassembled for cleaning, then complete regeneration can be achieved, but operational downtime increases and complexity increases

Engineering Contradiction:
Improvemembrane performanceVSAvoidoperational downtime
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements an in-situ cleaning system that allows the membrane unit to clean itself without disassembly. The cleaning gas is introduced through existing ports (permeate side inlet and retentate side outlet), enabling the membrane to regenerate while remaining installed, thus eliminating operational downtime and disassembly requirements.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If cleaning gas is introduced in the operating direction, then the process is simple, but contaminants are pushed deeper into the selective layer

Engineering Contradiction:
Improvecleaning process simplicityVSAvoidcontaminant removal effectiveness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent reverses the flow direction of the cleaning gas relative to the normal operating direction. By introducing cleaning gas through the permeate side and having it flow toward the retentate side (opposite to normal operation), the method prevents contaminants from being forced deeper into the selective layer while maintaining effective contaminant removal.

Inventive Principle:
Principle #13The other way round (Inversion)

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 allows for reliable removal of impurities without disassembling the membrane units, maintaining or restoring the initial performance by ensuring contaminants are not re-pressed into the selective layer, using a simpler setup and reducing operational downtime.

Implementation Method 1

a suitable gas or gas mixture, for example nitrogen or air, preferably hot air, is introduced on the permeate side of a gas permeation membrane unit to be cleaned

Methodology Applied
Scientific EffectThermal desorption: Desorption

Implementation Method 2

The removal of impurities takes place against the operating direction of the gas permeation membrane

Methodology Applied
Scientific EffectGas flow: Convection

Implementation Method 3

The operation of a gas permeation membrane is based on the solution-diffusion principle. This means that the different solubility and diffusion properties of the individual gases in a gas mixture to be separated are utilized within a plastic (which can be a polymer) acting as a separating layer

Methodology Applied
Scientific EffectSolution-diffusion: Diffusion

Data Source

PatentEP2870992B1Method for cleaning a gas permeation membrane
Publication Date: 2019.12.25 AXIOM ANGEWANDTE PROZESSTECHN M B H

AI summary

A method for cleaning a gas permeation membrane in a gas permeation membrane unit of impurities is described, wherein the removal of the impurities takes place against the operating direction of the gas permeation membrane.