Portable Raman hydrogen concentration mapping with parts-per-billion sensitivity

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Environmental Monitoring

Background:

• Accurate hydrogen detection is crucial for safety and industrial processes.
• Existing methods for hydrogen sensing can be limited in portability and sensitivity.
• The need for real-time, remote hydrogen monitoring is increasing.

Purpose of the Study:

• To develop and evaluate a portable multipass cavity Raman gas analyzer for hydrogen detection.
• To assess the instrument's performance in various environments, including outdoor settings.
• To demonstrate the analyzer's capability for sensitive hydrogen concentration mapping.

Main Methods:

• Utilized a portable multipass cavity Raman gas analyzer.
• Employed the vibrational band of hydrogen as the primary concentration measure.
• Integrated a desiccating gas handling system within a Pelican case for portability.
• Conducted measurements in laboratory, atrium, and outdoor environments.
• Measured hydrogen concentration over time and distance from a controlled source.

Main Results:

• The analyzer successfully mapped excess hydrogen concentrations as low as 63 parts per billion (one standard deviation) above ambient levels.
• Effective measurements were achieved from several meters away, including in an outdoor open space.
• The instrument demonstrated reliable performance with a measurement duration under 5 minutes per sample.
• Operated with a hydrogen source producing up to 600 mL/min at 0.34 MPa.

Conclusions:

• The portable Raman gas analyzer is a viable tool for sensitive hydrogen detection in diverse environments.
• The instrument's portability and sensitivity enable effective hydrogen leak detection and geological prospecting.
• This technology offers a promising solution for real-time, remote hydrogen monitoring applications.