Membrane Pervaporation Using Venturi Nozzle Vacuum

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Solution Overview

Problem

Existing membrane separation processes face challenges in achieving a sufficient vacuum on the downstream side of the membrane, particularly due to the limitations of vacuum pumps and steam ejectors, which are costly, require complex maintenance, and often necessitate additional treatment of effluent streams.

Innovation Solution

The use of a Venturi-type nozzle with a working fluid that is poorly miscible with the permeate, creating a vacuum without the need for vacuum pumps or steam ejectors, allowing for efficient separation of permeate from the working fluid through immiscibility and gravity separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If vacuum pumps are used to maintain low partial pressure of permeate, then vacuum is achieved, but maintenance cost increases and permeate condensation becomes difficult

Engineering Contradiction:

Improvepartial pressure of permeateVSAvoidmaintenance of vacuum pump

Core Design Contradiction:

Stress or pressureVSEase of repair

Solution Approach 1:

The invention extracts the vacuum generation function from complex vacuum pumps and implements it through a simple Venturi nozzle that uses fluid dynamics (pressure differential) to create vacuum, eliminating the need for mechanical vacuum pumping equipment and its associated maintenance issues

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the mechanical vacuum pump system with a fluid-based Venturi nozzle system that uses pressure differential and fluid flow to generate vacuum, substituting mechanical complexity with hydraulic simplicity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Stress or pressure

If steam ejectors are used to produce vacuum, then vacuum is achieved, but steam flow rate requirements increase and effluent treatment is needed

Engineering Contradiction:

Improvevacuum levelVSAvoidsteam flow rate

Core Design Contradiction:

Stress or pressureVSQuantity of substance

Solution Approach 1:

The invention uses a non-volatile working fluid in the Venturi nozzle that does not require the high steam flow rates needed by steam ejectors, and the working fluid is not contaminated by permeate, eliminating the need for effluent treatment

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention converts the pressure differential created by fluid flow through the Venturi nozzle into a beneficial vacuum effect, transforming what would be wasted pressure energy into useful vacuum generation without the harmful byproducts of steam ejectors

Inventive Principle:

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

3Stress or pressure

If a Venturi nozzle with a working fluid having affinity for permeate is used, then vacuum is produced, but permeate separation becomes complicated

Engineering Contradiction:

Improvevacuum on downstream sideVSAvoidpermeate separation process

Core Design Contradiction:

Stress or pressureVSDevice complexity

Solution Approach 1:

The invention inverts the conventional approach by using a working fluid that is immiscible with and has no affinity for the permeate, allowing permeate to be easily separated from the working fluid through simple phase separation rather than requiring complex separation processes

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 provides an efficient and cost-effective vacuum for membrane separation, reducing maintenance needs and improving the separation process by using a converging-diverging nozzle with a liquid working fluid that does not contaminate the permeate, enabling effective separation of multi-component feed streams without the limitations of traditional methods.

Implementation Method 1

the vacuum being produced by a fluid conducted through a Venturi nozzle

Methodology Applied

Scientific EffectVenturi effect: Venturi Effect

Implementation Method 2

selectively permeating at least the first species through the membrane from the first surface to an opposed second surface

Methodology Applied

Scientific EffectPermeation: Permeation

Implementation Method 3

under the influence of a concentration gradient that is produced by evaporating the sorbed molecules

Methodology Applied

Scientific EffectConcentration gradient: Diffusion

Implementation Method 4

the fluid comprises at least one solvent that is poorly miscible with the permeate

Methodology Applied

Scientific EffectImmiscibility: Liquid-Liquid Extraction

Implementation Method 5

efficient separation of permeate from the working fluid through immiscibility and gravity separation

Methodology Applied

Scientific EffectGravity separation: Gravitation

Data Source

PatentUS7497895B2Membrane separation process

Publication Date: 2009.03.03 EXXONMOBIL TECHNOLOGY & ENGINEERING CO

AI summary

The invention relates to an improved membrane pervaporation and vapor permeation system in which the vacuum is produced by a fluid passing through a Venturi-type nozzle. The fluid is chosen from solvents that have little or no affinity for the permeate molecules. It is applicable over process feed rates, and can be used for the separation of aromatic species from hydrocarbon.