Chemometric Model for Laser Spectroscopy Gas Analysis
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Solution Overview
Problem
Current laser absorption spectrometry methods for measuring hydrocarbon fuel contaminants face inaccuracies due to variable concentrations of background gases, leading to complex post-processing and calibration procedures.
Innovation Solution
The method involves obtaining measured gas concentration data for background gases and light absorption data for target components, using a chemometric model with a broadband offset basis to iteratively adjust fit coefficients until the measured data matches the model, and applying these coefficients to determine the target component concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If empirical models and multivariate fitting routines are used to measure contaminant concentrations in fuel gas, then measurement capability is provided, but measurement precision deteriorates due to variable background gas concentrations
Solution Approach 1:
The system performs preliminary measurement of background gas concentrations (methane, propane, etc.) before conducting the contaminant analysis. This preliminary action allows the chemometric model to account for variable background compositions, thereby improving measurement precision and reliability of contaminant concentrations.
Solution Approach 2:
The system dynamically adjusts the chemometric model parameters based on measured background gas concentrations. By changing the model parameters according to actual background composition, the system maintains high measurement precision even when background gases vary, resolving the contradiction between measurement capability and precision.
2Measurement precision
If iterative calibration processes with multiple input parameters are implemented, then measurement capability is enhanced, but device complexity increases
Solution Approach 1:
The system combines the background gas measurement, chemometric modeling, and contaminant analysis into an integrated post-processing workflow. By merging these functions, the system reduces overall complexity while maintaining enhanced measurement precision through the use of multiple input parameters.
Solution Approach 2:
The chemometric model automatically adjusts its parameters based on measured background gas concentrations without requiring manual calibration. This self-service approach reduces device complexity by eliminating tedious post-calibration procedures while maintaining high measurement precision.
3Ease of operation
If background gas concentrations are not accounted for, then measurement process is simplified, but measurement precision deteriorates
Solution Approach 1:
The system extracts and separately measures background gas concentrations before performing contaminant analysis. By taking out the background gas measurement as a distinct step, the system maintains ease of operation through clear separation of functions while improving precision by accounting for background interference in the chemometric model.
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 improves the accuracy of contaminant measurement in hydrocarbon fuel mixtures by accounting for variable background gas concentrations, reducing errors and simplifying the calibration process.
Implementation Method 1
laser spectroscopy instrument configured to measure light absorption of the one or more gaseous target components within the sample gas, each of the one or more gaseous target components having an absorption spectrum at the frequency of light or at a combination of frequencies of frequencies of light
Data Source
AI summary
The present disclosure relates to measuring chemical constituents and associated properties of hydrocarbon fuel mixtures, and further relates to tunable diode laser absorption spectrometry gas analyzers having improved chemometric models. Methods described herein include setting gas concentration fit coefficients to a chemometric model for the measured gas concentration data for each of one or more background; wherein the chemometric model employs a broadband offset basis to a final basis set spectrum for the one or more gaseous target components; applying an iterative mathematical model to the measured light absorption data by iteratively adjusting target component fit coefficients until the measured light absorption data matches the chemometric model; and, determining a calculated amount of the one or more target components within the sample gas mixture by applying the gas concentration fit coefficients and the target component fit coefficients to the measured light absorption data and to the measured gas concentration data.