Gas Measurement Using Static Fourier Transform Infrared Spectrometers

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Process Engineering

Background:

• Online gas monitoring in industrial settings faces challenges from vibrations and temperature variations.
• Conventional Fourier transform infrared (FTIR) spectrometers require complex designs for stability.
• Static FTIR spectrometers offer inherent stability and lower costs due to the absence of moving parts.

Purpose of the Study:

• To introduce a novel, compact gas measurement system utilizing a static single-mirror Fourier transform spectrometer (sSMFTS).
• To enable sensitive quantification of gas concentrations in industrial processes.
• To demonstrate the system's applicability for online monitoring under challenging conditions.

Main Methods:

• Development and implementation of a static single-mirror Fourier transform spectrometer (sSMFTS).
• Operation in the mid-infrared range (650 cm⁻¹ to 1250 cm⁻¹).
• Integration with a customized White cell for extended optical path lengths (up to 120 cm).
• Validation using measurements of 1,1,1,2-Tetrafluoroethane (R134a) at various concentrations.
• Analysis of acquired infrared spectra using Partial Least Squares (PLS) regression.

Main Results:

• The sSMFTS system achieved high sensitivity for gas quantification.
• Measured absorption spectra of R134a showed excellent agreement with reference data.
• The system demonstrated high measurement rates (up to 200 Hz) and high signal-to-noise ratios.

Conclusions:

• The novel static FTIR spectrometer provides a stable and cost-effective solution for online gas monitoring.
• The system's performance indicates strong potential for applications in industrial process analysis.
• The compact design and high performance make it suitable for demanding environments.