Tar Content Detection via Residual Oxygen Comparison

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Solution Overview

Problem

Current methods for detecting tar content in measurement gas mixtures, particularly in biogenic gasification processes, are complex and inefficient, especially when trying to minimize tar content in synthesis gas used for organic compound production or as fuel, due to the interference of other oxidizable components.

Innovation Solution

A method utilizing an oxygen sensor, such as a lambda probe, to indirectly detect tar content by measuring residual oxygen levels after oxidizable components have reacted, allowing for the calculation of tar content through a calibration curve based on oxygen consumption differences with and without tar present.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a flame ionization detector (FID) is used to determine tar content by comparing signals with and without tar depletion, then the tar content can be detected, but the measurement is complicated by the presence of other oxidizable components that create background interference

Engineering Contradiction:
Improvetar content detection accuracyVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The measurement process is segmented into two separate measurement paths: one for measuring total oxygen consumption (including tar) and another for measuring oxygen consumption of oxidizable components only (without tar). This segmentation allows the tar content to be calculated as the difference between the two measurements, eliminating background interference from other oxidizable components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tar component is extracted from the gas mixture by condensing it out in a condensation trap before the gas reaches the oxygen sensor in the second measurement path. This extraction allows the oxygen consumption of non-tar oxidizable components to be measured separately, enabling accurate tar content determination through comparison.

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If direct determination of organic composition with and without tar depletion is performed, then tar content can be measured, but the low tar content signal must be evaluated against a high background signal from other oxidizable components

Engineering Contradiction:
Improvetar content measurement accuracyVSAvoidsignal detection difficulty
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

Oxygen consumption is used as an intermediary parameter to indirectly measure tar content. Instead of directly measuring tar or organic composition, the method measures oxygen consumption differences, which serve as a mediator that amplifies the tar signal while eliminating background interference from other oxidizable components.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If tar content is measured as a sum parameter to simplify control of gasification plants, then the measurement becomes more practical, but the heterogeneous composition of tar makes direct measurement difficult

Engineering Contradiction:
Improvegasification plant control simplicityVSAvoidtar composition measurement difficulty
Core Design Contradiction:
Ease of operationVSDifficulty of detecting and measuring

Solution Approach 1:

The measurement approach changes from directly analyzing tar composition to measuring oxygen consumption parameters. By changing the measurement parameter from organic composition analysis to oxygen consumption difference, the method simplifies the measurement process while accurately capturing the total tar content as a sum parameter suitable for process control.

Inventive Principle:
Principle #35Parameter changes

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 simplifies tar content determination by isolating its measurement from other oxidizable components, enabling effective control of gasification processes to minimize tar content, even in stoichiometric and heterogeneous mixtures.

Implementation Method 1

organic compounds are determined based on the conductivity of an oxyhydrogen flame

Methodology Applied
Scientific EffectFlame ionization: Ionisation

Implementation Method 2

an electrochemical oxygen sensor based on the amperometric and/or potentiometric measuring principle

Methodology Applied
Scientific EffectElectrochemical detection:

Implementation Method 3

a catalytic converter for the oxidation of carbon monoxide to carbon dioxide

Methodology Applied
Scientific EffectCatalytic oxidation: Catalysis

Implementation Method 4

oxidation of carbon monoxide to carbon dioxide

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 5

a condensation trap for the removal of tar from the sample gas mixture

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP3647780B1Method and measuring system for detecting a tar content in gases
Publication Date: 2021.08.18 HOCHSCHULE KARLSRUHE TECHN & WIRTSCHAFT
  • EP3647780B1 patent drawingFigure 1~3
  • EP3647780B1 patent drawingFigure 4
  • EP3647780B1 patent drawing

AI summary

The invention relates to a method for determining the tar content in a sample gas mixture (2) containing oxidizable components and a measuring system (1) for carrying out the method, comprising at least the following process steps: - extraction of at least one partial stream (3, 4) of the sample gas mixture (2), - addition of a predetermined amount of oxygen to the at least one partial stream (3, 4), - modification of the oxygen content by complete conversion of oxidizable components present in the at least one partial stream (3, 4, 4c) to residual oxygen contents (ROC(R), ROC(M)), - determination of a first residual oxygen content (ROC(R)) dependent on a reduction of the tar content provided by means of a reduction device (9) using at least one oxygen sensor (19), - determination of a second residual oxygen content (ROC(M)) using at least one oxygen sensor (18) without reduction of the tar content.- Determination of a sum parameter of the tar content from a comparison of the two residual oxygen contents (ROC(M), ROC(R)).