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 simultaneous measurements of 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 for spectral data manipulation allows for the simultaneous determination of carbon monoxide, gaseous water, and gaseous hydrocarbons using a single laser source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tunable diode laser spectroscopy is used for simultaneous analysis of CO, H2O, and hydrocarbons in combustion gases, then measurement capability is provided, but sensitivity and accuracy are poor due to background interferences and temperature effects
Solution Approach 1:
The patent changes the operating wavelength parameter from conventional near-infrared (1.56 micron) to mid-infrared (2.0-2.5 micrometers) range, where CO, H2O, and hydrocarbon molecules have distinct absorption bands. This parameter change enables better spectral separation and reduces overlapping background interferences, thereby improving measurement precision and sensitivity simultaneously.
2Device complexity
If a single tunable diode laser is used for simultaneous measurement of multiple gas species, then device simplicity is maintained, but measurement precision deteriorates due to spectral overlap and interference
Solution Approach 1:
The patent segments the spectral measurement by selecting distinct wavelength ranges (2.0-2.5 micrometers) where different gas species have non-overlapping absorption characteristics. By dividing the spectral domain into separate bands for CO, H2O, and hydrocarbons, a single laser source can measure multiple species without significant spectral interference, maintaining device simplicity while improving measurement precision.
Solution Approach 2:
The patent introduces multivariate processing techniques as an intermediary between the single laser source and the measurement results. This intermediary processes the spectral data to resolve overlapping signals and extract accurate concentrations of multiple gas species, enabling precise simultaneous measurement with a single laser source.
3Use of energy by moving object
If conventional near-infrared wavelength (1.56 micron) is used for TDL measurements, then existing equipment is utilized, but sensitivity and measurement accuracy are insufficient for simultaneous multi-gas analysis
Solution Approach 1:
The patent changes the operational wavelength parameter from 1.56 micron to 2.0-2.5 micrometers, accessing different molecular absorption bands. This parameter change reveals that while the original wavelength can detect certain gases, the new wavelength range provides superior sensitivity and accuracy for simultaneous detection of CO, H2O, and hydrocarbons by exploiting their distinct mid-infrared absorption characteristics.
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 enhances sensitivity and enables accurate simultaneous analysis of key combustion species, improving combustion efficiency, reducing emissions, and ensuring safe operation in hydrocarbon processing furnaces.
Implementation Method 1
tunable diode laser spectroscopic analysis of combustion gases
Implementation Method 2
In the absorption spectrum a CO absorption line and H2O absorption line which are sufficiently close to permit rapid simultaneous measurement with a single laser source are selected
Data Source
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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.