Raman Spectroscopy for Temporally Resolved Combustion Gas Diagnostics

Area of Science:

• Combustion diagnostics
• Spectroscopy
• Chemical engineering

Background:

• Traditional absorption spectroscopy struggles to analyze certain combustion gases.
• Real-time, in-line monitoring of combustion processes is crucial for efficiency and safety.

Purpose of the Study:

• To present a novel, cost-effective, and temporally resolved in-line combustion gas diagnostic instrument.
• To enable the measurement of gas species concentrations, including H2 and N2, not easily detectable by absorption methods.

Main Methods:

• Utilized spontaneous Stokes Raman spectroscopy with a multipass configuration to enhance scattering.
• Developed a calibrated system for both qualitative and quantitative analysis of gas composition.
• Characterized the instrument's response across a pressure range of 0.7 to 7.5 bar.

Main Results:

• The instrument provides detailed spectral information from H2 rotational peaks (587 cm⁻¹) to vibrational peaks (4156 cm⁻¹).
• Successfully covered Raman emissions of major combustion species.
• Demonstrated a working integration time range from 0.15s to 10s.

Conclusions:

• The developed Raman spectroscopy instrument offers a viable solution for cost-effective, in-line combustion gas diagnostics.
• The portable and adaptable prototype is ready for industrial applications.
• The system provides valuable quantitative and qualitative data for combustion process optimization.