Combustion Emission Control via Fuel Analysis

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Solution Overview

Problem

The challenge is to comply with increasingly stringent emission limit values in combustion processes, particularly in industries using secondary fuels, where the inhomogeneous material quality of these fuels makes it difficult to maintain consistent calorific values and pollutant content, leading to varying emissions and quality issues in products like cement clinker.

Innovation Solution

The method involves conducting a first chemical analysis of the fuel or fuel mixture during conveyance to the combustion zone, using techniques like terahertz spectroscopy, and adjusting the combustion process based on the results. A subset of the fuel is then discharged, comminuted, and analyzed further with a second chemical analysis, where it is mixed with a mineral or inorganic salt, and the resulting sample is analyzed to ensure compliance with emission standards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If secondary fuels with high energy content are used to increase productivity, then the proportion of secondary fuels in combustion process increases, but the inhomogeneous material quality causes strongly varying emissions and calorific values making it difficult to comply with emission limit values

Engineering Contradiction:
Improveproportion of secondary fuelsVSAvoidemission compliance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by performing chemical analysis of the secondary fuel feed material before it enters the combustion zone. The analysis device detects calorific value, sulfur content, chlorine content, and other parameters in advance, allowing the control system to adjust combustion parameters proactively to ensure emission compliance while maximizing secondary fuel usage.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback control by continuously monitoring the chemical composition of the secondary fuel feed material and using this information to dynamically adjust combustion air supply, fuel feed rate, and other combustion parameters. This closed-loop control ensures that emission limits are maintained even when fuel quality varies, allowing high proportions of secondary fuels to be used reliably.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If chemical analysis is performed on secondary fuels with strongly fluctuating composition, then reliable statements about material quality can be made, but the heterogeneity of secondary fuels makes it difficult to obtain representative samples

Engineering Contradiction:
Improvematerial quality analysisVSAvoidsample representativeness
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent extracts a sample of the secondary fuel feed material directly from the conveyance line before combustion. This extracted sample is then analyzed by the chemical analysis device to determine calorific value, sulfur content, chlorine content, and other parameters. By taking out a representative sample for analysis, the system can make reliable statements about the overall fuel quality without disrupting the main combustion process.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces complex mechanical sampling and preparation systems with a chemical analysis device that can analyze the fuel feed material directly in its conveyed state. The device uses spectroscopic or chemical methods to determine composition parameters without requiring extensive sample preparation, comminution, or homogenization, thereby simplifying the measurement process while maintaining accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If wet-chemical analyzes are used to determine material composition and pollutant content, then accurate emission predictions can be made, but the cost of analysis becomes very high due to strongly fluctuating composition

Engineering Contradiction:
Improvepollutant content analysisVSAvoidanalysis cost
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent employs a chemical analysis device that uses rapid, cost-effective analytical methods such as spectroscopy or simple chemical sensors instead of expensive wet-chemical analysis. These methods provide sufficient precision for determining sulfur content, chlorine content, and calorific value at a fraction of the cost of traditional laboratory analysis, enabling continuous monitoring without prohibitive expenses.

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

Solution Approach 2:

The patent replaces expensive wet-chemical analysis with instrumental analysis methods such as spectroscopy, X-ray fluorescence, or other rapid detection techniques. These methods provide accurate measurements of pollutant content and calorific value without the need for time-consuming laboratory procedures, expensive reagents, or specialized personnel, thereby significantly reducing analysis costs while maintaining measurement precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 allows for real-time control of the combustion process, ensuring consistent fuel quality and emission compliance by adjusting fuel quantities, combustion air, or flame shape, thereby maintaining homogeneous calorific values and reducing pollutant emissions.

Implementation Method 1

the fuel or fuel mixture is subjected to at least one first chemical analysis while it is being conveyed to the combustion zone

Methodology Applied
Scientific EffectTerahertz spectroscopy: Absorption Spectroscopy

Data Source

PatentEP3322937B1Method for observing emission limits in a combustion process
Publication Date: 2019.11.06 THYSSENKRUPP AG
  • EP3322937B1 patent drawingFigure 1
  • EP3322937B1 patent drawingFigure 2
  • EP3322937B1 patent drawingFigure 3

AI summary

The invention relates to a method for observing emission limits in a combustion process, in which at least one fuel (1) or at least one fuel mixture is used, said fuel or fuel mixture being supplied to at least one combustion zone via a supply path. The fuel (1) or fuel mixture undergoes at least one first chemical analysis as it is being conveyed to the combustion zone, wherein the values detected during said first chemical analysis are used to control the combustion process.