Substitute Fuel Calorific Value Control in Cement Clinker Production

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Solution Overview

Problem

The inhomogeneous nature of substitute fuels, which have varying calorific values and moisture content, leads to process fluctuations in thermal treatment processes like cement clinker production, as existing methods can only react to changes after they occur, resulting in inefficient energy supply and temperature fluctuations.

Innovation Solution

Implementing a method that uses spatially resolved sensors to detect substitute fuels on conveyor devices, estimating their calorific values, and adjusting the material flow by controlling the conveying speed to maintain consistent energy input, thereby preventing temperature fluctuations and optimizing energy use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If substitute fuels with varying calorific values are used to replace primary fuels, then cost is reduced and resources are conserved, but process fluctuations and temperature variations occur

Engineering Contradiction:
Improveenergy efficiencyVSAvoidprocess stability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The system performs preliminary determination of the calorific value of substitute fuels using vibrational spectroscopic analysis before combustion. This advance knowledge allows the control system to pre-adjust the material flow rate of substitute fuels to compensate for calorific value variations, preventing temperature fluctuations rather than merely reacting to them.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements a closed-loop control mechanism where the calorific value determined by vibrational spectroscopy feeds into the control system, which then adjusts the material flow rate accordingly. This feedback loop ensures that variations in fuel quality are continuously compensated for, maintaining stable combustion conditions and temperature.

Inventive Principle:
Principle #23Feedback

2Temperature

If the material flow of substitute fuels is adjusted based on actual temperature, then temperature control is achieved, but the control system can only react to changes that have already occurred

Engineering Contradiction:
Improvetemperature controlVSAvoidresponse time
Core Design Contradiction:
TemperatureVSLoss of time

Solution Approach 1:

Instead of waiting for temperature changes to occur before adjusting material flow, the system performs preliminary determination of calorific value using vibrational spectroscopy. This allows the control system to proactively adjust the material flow rate before temperature deviations occur, eliminating the time delay inherent in reactive temperature-based control.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If average calorific value is used for calculation, then simplification is achieved, but process fluctuations arise due to energy supply variations

Engineering Contradiction:
Improvecontrol system complexityVSAvoidenergy supply consistency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system replaces simple average calorific value calculations with a feedback-based control mechanism. Vibrational spectroscopic analysis provides real-time information about the actual calorific value, which feeds into the control system to dynamically adjust material flow rates. This feedback loop maintains energy supply consistency without requiring complex manual intervention or overly complicated control algorithms.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system replaces mechanical/chemical analysis methods for determining calorific value with vibrational spectroscopic analysis. This substitution provides rapid, non-contact measurement that is both simple to implement and highly effective at preventing process fluctuations, achieving reliability without proportionally increasing complexity.

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 precise prediction and adjustment of energy input, minimizing process fluctuations and ensuring consistent temperature control, thereby enhancing the efficiency and stability of thermal treatment processes.

Implementation Method 1

From WO 2017/009158 A1 a method for controlling a combustion process with at least one substitute fuel by means of a vibrational spectroscopic analysis is known.

Methodology Applied
Scientific EffectVibrational spectroscopy: Vibration

Implementation Method 2

at least one first substitute fuel is used... The first alternative fuel is transported from the first feed area to a first combustion area with at least one first conveying device

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP4259972B1Method for the optimized combustion of substitute fuels in a device for the thermal treatment of inorganic materials, more particularly for the production of cement clinker
Publication Date: 2024.10.23 THYSSENKRUPP POLYSIUS GMBH
  • EP4259972B1 patent drawingFigure 1

AI summary

The present invention relates to a method for the thermal treatment of inorganic materials, more particularly for the production of cement clinker, wherein: - at least a first substitute fuel is used for the production; - the first substitute fuel is fed in a first feeding region (40); - the first substitute fuel is transported from the first feeding region (40) to a first combustion region by means of at least a first conveying device (50), a continuously transporting conveying device being selected as the first conveying device (50); - the first substitute fuel is sensed by means of a first sensor (60) having at least linear resolution, the first sensor (60) being above the first conveying device (50); - spatially resolved material information of the first substitute fuel is determined from the information captured by means of the first sensor (60); - a first calorific value is estimated from the spatially resolved material information of the first substitute fuel; - a first value is specified for the required heat energy in the first combustion region; - the first material flow of the first substitute fuel of the estimated first calorific value is adapted to the specified heat energy by means of adaptation of the material flow.