Optical Flame Sensor for Coal Combustion Monitoring
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Solution Overview
Problem
Existing optical monitoring methods struggle to accurately determine hot spots and particle size in coal combustion flames due to light scattering by solid coal particles, making it difficult to control nitrogen oxide and carbon monoxide formation effectively, especially in large-scale coal burning power plants where expensive and maintenance-intensive optical equipment is required.
Innovation Solution
A cost-effective optical measurement device using a color camera to detect light information from the flame, combined with an evaluation unit that processes data to determine temperature and particle size, employing modified black body radiation spectra and Mie scattering theory to account for light scattering, allowing for spatially resolved measurements and control of combustion parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional spectroscopy methods are used for optical monitoring of coal combustion, then temperature and hot spot detection can be achieved, but measurement accuracy deteriorates due to light scattering by solid coal particles
Solution Approach 1:
The patent converts the harmful light scattering effect into a useful measurement signal. By detecting the scattered light intensity and applying Mie scattering theory, the system determines coal particle size distribution. The scattered light that previously degraded temperature measurement accuracy is now used to characterize particle properties, which are then used to correct the temperature measurements.
Solution Approach 2:
The patent changes the measurement parameters from direct spectroscopic temperature measurement to a two-step approach: first measuring scattered light intensity to determine particle size, then using this particle size information to correct the temperature measurement. This parameter transformation allows the system to account for the scattering effects and retrieve accurate temperature and hot spot information.
2Measurement precision
If expensive and maintenance-intensive optical equipment is used for coal combustion monitoring, then measurement accuracy can be maintained, but device complexity and operational cost increase
Solution Approach 1:
The patent replaces expensive, maintenance-intensive optical equipment with a color camera, which is a cheap and widely available device. The color camera captures RGB images of the flame, and through image processing and application of combustion theory, extracts temperature and particle size information. This substitution dramatically reduces device complexity and operational costs while maintaining measurement capability.
Solution Approach 2:
The patent substitutes complex optical measurement systems with a simpler digital imaging system. Instead of using specialized spectroscopic instruments, the system uses a color camera to capture light information, which is then processed computationally to derive combustion parameters. This substitution leverages digital image processing to replace sophisticated optical hardware.
3Object-generated harmful factors
If particle size variation is not controlled in coal combustion, then combustion process simplicity is maintained, but nitrogen oxide and carbon monoxide formation increase
Solution Approach 1:
The patent implements a feedback mechanism where the color camera continuously monitors the flame, detects particle size distribution through scattered light analysis, and provides this information for combustion control. The system uses the detected particle size and temperature information to adjust combustion parameters, creating a closed-loop control system that reduces harmful emissions while maintaining efficiency.
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 enables efficient reduction of nitrogen oxide formation, optimization of combustion processes, and improved efficiency by accurately measuring hot spots and particle sizes, reducing the need for expensive optical equipment and allowing for individual burner stoichiometry balancing in coal burning power plants.
Implementation Method 1
employing modified black body radiation spectra to account for light scattering
Implementation Method 2
employing modified black body radiation spectra and Mie scattering theory to account for light scattering
Data Source
AI summary
The disclosure relates to an optical measurement device (100) adapted for determining the temperature in a flame and for determining the particle size of the fuel present in the flame. The optical measurement device (100) includes a colour camera (10) for measuring light information in the flame and outputting measurement results and an evaluation unit (20) adapted for evaluating the measurement results. Further, a coal burning power plant (200) is provided with a multitude of burners (35) for burning milled coal each in a flame and a multitude of optical measurement devices (100) described. Further, an according method for determining the temperature and particle size of the fuel present in a flame is provided.