Multi-Stage Gas Preconcentration System for VOC Analysis

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Solution Overview

Problem

Conventional methods for sampling and preparing gaseous samples are limited by the breakthrough volume, which restricts the concentration factor of volatile organic compounds (VOCs) without allowing changes to operating conditions like temperature or adsorbent quantity.

Innovation Solution

A multi-stage system with interconnected preconcentration units and fluidic control means allows for repeated cycles of sample transfer and heating to increase the concentration factor beyond the breakthrough volume, decoupling it from the adsorbent's capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional single-stage preconcentration is used, then the system operates with simple structure, but the concentration factor is limited by the breakthrough volume

Engineering Contradiction:

Improveconcentration factorVSAvoidsystem structure

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The preconcentration system is divided into multiple stages (first stage, second stage, etc.), each with its own preconcentration unit and fluidic path. The gas sample flows sequentially through each stage, allowing cumulative concentration that exceeds the breakthrough volume limitation of any single stage while maintaining manageable complexity through modular design

Inventive Principle:

Principle #1Segmentation

2Quantity of substance

If temperature or adsorbent quantity is increased to improve concentration, then the concentration factor increases, but the operating conditions of the system must be changed

Engineering Contradiction:

Improveconcentration factorVSAvoidoperating conditions flexibility

Core Design Contradiction:

Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

Instead of increasing concentration in a single dimension (one preconcentration unit), the system adds another dimension by implementing multiple sequential stages. Each stage contributes to the overall concentration factor multiplicatively, allowing high concentration to be achieved without modifying temperature, pressure, or adsorbent properties in any single unit

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 approach enhances the concentration factor of gaseous samples without altering the system's operating conditions, effectively increasing the trapped VOCs' concentration by leveraging the adsorbent's capacity rather than its breakthrough volume.

Implementation Method 1

Solid adsorbent concentration uses an adsorbent, usually in powder form, to trap VOCs by physisorption at room temperature

Methodology Applied

Scientific EffectPhysisorption: Physisorption

Implementation Method 2

The adsorbent can then be heated to release its VOC content, to an analysis device such as a gas chromatograph for example

Methodology Applied

Scientific EffectThermal desorption: Desorption

Data Source

PatentEP4177590A1Method and system for collecting and preparing a gas sample

Publication Date: 2023.05.10 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

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Figure 3A~3B
Figure 3C~4

AI summary

The invention relates to a method for sampling and preparing a gaseous sample to be analyzed, said method consisting of carrying out several times a cycle which includes the steps of: - Loading a gaseous sample into a pre-concentration unit (U_i) of rank i, - Transferring said gaseous sample from the pre-concentration unit (U_i) of rank i to the pre-concentration unit (U_i+1) of the concentration stage of rank i+1 by activating the fluidic control means associated with the concentration stage of rank i+1.