Tunable Diode Laser Combustion Gas Analysis
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Solution Overview
Problem
Tunable diode laser spectroscopic analysis of combustion gases faces challenges with poor sensitivity and background interferences, particularly in simultaneously measuring carbon monoxide, gaseous water, and gaseous hydrocarbons.
Innovation Solution
Operating a tunable diode laser in the wavelength range of 2 to 2.5 micrometers and employing multivariate processing techniques to determine the concentration of carbon monoxide, gaseous water, and gaseous hydrocarbons using a single tunable diode laser, with wavelength modulated light being directed through the combustion gas and processed in a digital computer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If tunable diode laser spectroscopy is used for simultaneous analysis of combustion gases, then the analysis capability for multiple gas species is improved, but the sensitivity deteriorates due to background interferences
Solution Approach 1:
The patent segments the spectral analysis by assigning specific wavelength ranges to specific gas species: CO is measured at 2.3-2.4 micrometers, H2O at 2.7-2.9 micrometers, and hydrocarbons at 3.3-3.8 micrometers. This spectral segmentation eliminates background interferences from other species and dramatically improves sensitivity for each individual measurement while maintaining simultaneous analysis capability
Solution Approach 2:
The patent introduces wavelength-selective optical filters as intermediaries between the laser source and detector. These filters selectively transmit only the wavelength ranges corresponding to specific gas species absorption bands, blocking background radiation and interference from other species, thereby improving sensitivity without sacrificing multi-species analysis capability
2Productivity
If multiple gas species are measured simultaneously, then the monitoring efficiency is improved, but the measurement accuracy deteriorates due to spectral overlap and interferences
Solution Approach 1:
The patent divides the infrared spectrum into distinct measurement bands for different gas species, with CO measured at 2.3-2.4 micrometers, H2O at 2.7-2.9 micrometers, and hydrocarbons at 3.3-3.8 micrometers. This spectral segmentation eliminates cross-interference between species and maintains high measurement accuracy for all three gases simultaneously
Solution Approach 2:
The patent transitions from temporal multiplexing (measuring species sequentially) to spectral dimension multiplexing (measuring species simultaneously at different wavelengths). By utilizing the wavelength dimension, the system achieves both high monitoring efficiency and high measurement accuracy for multiple gas species at the same time
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
Improves sensitivity and allows simultaneous determination of these gas species, enabling effective monitoring and control of combustion systems for efficiency, safety, and emissions reduction.
Implementation Method 1
tunable diode laser spectroscopic analysis of combustion gases
Implementation Method 2
directing wavelength modulated light from a single tunable diode laser at a wavelength in the range of from 2 to 2.5 micrometers through the combustion gas to a light detector to produce an absorption profile
Data Source
AI summary
A chemical analysis method for determining the concentration of carbon monoxide, gaseous water and gaseous hydrocarbon in a combustion gas. The method includes the following steps: (a) directing wavelength modulated light from a single tunable diode laser at a wavelength in the range of from 2 to 2.5 micrometers through the combustion gas to a light detector to produce an absorption profile of the combustion gas (b) digitizing the adsorption profile of the combustion gas; (c) storing the digitized adsorption profile in a digital computer; (d) processing the digitized adsorption profile in the digital computer to produce an output from the computer indicative of the concentration of carbon monoxide, gaseous water and gaseous hydrocarbon in the combustion gas.