Laser Gas Analyzer for Marine Exhaust with Dust and Water Correction
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Solution Overview
Problem
Conventional laser-type gas analyzers require multiple devices to measure SO2 and CO2 concentrations in marine exhaust gas, leading to increased costs and equipment size, and struggle to accurately measure SO2 concentrations due to interference from water and dust.
Innovation Solution
A single-device laser-type gas analyzer that uses a mid-infrared laser to measure SO2 and a near-infrared laser to measure CO2, with advanced signal processing to correct for water and dust interference, allowing precise concentration measurement in environments with high dust and water concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single laser-type gas analyzer is used to measure both SO2 and CO2 concentrations, then device cost and size are reduced, but measurement precision deteriorates due to interference from water and dust
Solution Approach 1:
The patent divides the measurement system into separate functional modules: a mid-infrared laser unit for SO2 measurement and a near-infrared laser unit for CO2 and water measurement. This segmentation allows each laser to be optimized for its specific wavelength range while enabling multi-gas measurement capability in a single device, resolving the contradiction between device consolidation and measurement precision.
Solution Approach 2:
The patent introduces water vapor concentration measurement as an intermediary parameter. By measuring water vapor using the near-infrared laser and using this information to correct the SO2 measurement, the system compensates for water interference. This intermediary approach allows accurate SO2 measurement despite the presence of interfering water vapor in the exhaust gas.
2Adaptability or versatility
If conventional laser-type gas analyzers are used in environments with high dust concentration, then gas concentration can be measured, but measurement precision deteriorates due to dust-induced light attenuation
Solution Approach 1:
The patent uses a reference gas (nitrogen or carbon dioxide) as an intermediary to measure dust concentration. By measuring the absorption of the reference gas, which is not affected by water vapor, the system calculates dust concentration and uses this information to correct the target gas measurement. This intermediary approach enables accurate gas measurement in dusty environments.
Solution Approach 2:
The patent implements feedback correction by continuously measuring dust concentration using the reference gas and using this information to adjust the target gas concentration calculation. The system feeds back the dust concentration data to correct the absorption measurements, compensating for dust-induced light attenuation and maintaining measurement precision in dusty environments.
3Measurement precision
If multiple laser-type gas analyzers are used to measure SO2 and CO2, then measurement precision is maintained, but device cost and equipment size increase
Solution Approach 1:
The patent merges multiple laser-type gas analyzers into a single integrated device by combining a mid-infrared laser unit and a near-infrared laser unit in one instrument. This merging allows simultaneous measurement of SO2, CO2, and water vapor concentrations while maintaining measurement precision through specialized wavelength selection for each gas, thereby reducing device cost and size.
Solution Approach 2:
The patent creates a universal gas analyzer capable of measuring multiple gases (SO2, CO2, and water vapor) using different laser wavelengths within a single device. This multi-functionality eliminates the need for separate analyzers for each gas, reducing overall device complexity and cost while maintaining the measurement precision required for marine exhaust gas analysis.
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
Enables accurate and precise measurement of both SO2 and CO2 concentrations using a single device, overcoming the limitations of conventional analyzers by effectively distinguishing between gas absorption and dust-induced light attenuation.
Implementation Method 1
a mid-infrared laser light-emitting unit that emits laser light of a wavelength band of a mid-infrared region that includes an optical absorption spectrum of a first gas to be measured
Implementation Method 2
a near-infrared laser light-emitting unit that emits, at respective times, first laser light of a wavelength band of a near-infrared region that includes an optical absorption spectrum of a second gas to be measured
Implementation Method 3
second laser light of a wavelength band of a near-infrared region that includes an optical absorption spectrum of water
Data Source
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AI summary
Provided is a laser-type gas analyzer that can measure, with high precision and in use of one single device, the gas concentration of a first gas to be measured in a mid-infrared region, and the gas concentration of a second gas to be measured, in a near-infrared region even in a measurement environment where dust and water at a high concentration are present. The laser-type gas analyzer includes: a mid-infrared light reception signal processing and computing unit 22 that calculates a gas concentration of the first gas to be measured on the basis of a mid-infrared light reception signal; a near-infrared light reception signal processing and computing unit 23 that detects, at respective times, the gas concentration of the second gas to be measured, water concentration in a space, and alight amount decrement due to dust, on the basis of near-infrared light reception signal; and a gas concentration correcting unit 24 that corrects the gas concentrations of the first and second gases to be measured using the water concentration and the light amount decrement.