Range-resolved detection of potassium chloride using picosecond differential absorption light detection and ranging

Area of Science:

• Combustion diagnostics
• Laser spectroscopy
• Chemical sensing

Background:

• Accurate measurement of alkali compounds like potassium chloride (KCl) is crucial for optimizing combustion processes and preventing corrosion in industrial boilers and furnaces.
• Limited optical access in large-scale industrial environments poses significant challenges for conventional diagnostic techniques.

Purpose of the Study:

• To present a novel laser diagnostic concept for quantitative, range-resolved measurement of potassium chloride (KCl) and other alkali compounds.
• To evaluate the performance of picosecond differential absorption light detection and ranging (DIAL) in challenging industrial settings with restricted optical access.

Main Methods:

• Development and application of a single-ended, range-resolved picosecond differential absorption light detection and ranging (DIAL) system.
• Experimental comparison of picosecond DIAL measurements with a commercial in situ alkali chloride monitor (IACM) utilizing differential optical absorption spectroscopy.
• Implementation of a double-pulse DIAL setup to address dynamic conditions and strong Mie scattering.

Main Results:

• Picosecond DIAL achieved centimeter-scale range resolution and quantitative KCl detection at concentrations around 130 ppm at 1200 K over a 2.5 m collection distance.
• Measurements showed good agreement with the commercial IACM instrument, validating the DIAL technique.
• A detection limit of approximately 30 ppm for KCl was determined under the experimental conditions.

Conclusions:

• Picosecond DIAL is a viable and accurate method for measuring KCl concentrations in industrial boilers and furnaces, even with limited optical access.
• The developed technique offers significant advantages in terms of range resolution and quantitative detection compared to existing methods.
• The findings support the potential implementation of this laser diagnostic for real-time monitoring in industrial environments to improve efficiency and prevent operational issues.