Highly range-resolved ammonia detection using near-field picosecond differential absorption lidar

Area of Science:

• Environmental Science
• Analytical Chemistry
• Combustion Engineering

Background:

• Ammonia (NH3) is vital for reducing nitric oxide (NO) emissions in combustion processes.
• Efficient non-catalytic reduction requires optimal ammonia mixing with flue gases.
• Accurate, real-time monitoring of ammonia distribution is essential for process control.

Purpose of the Study:

• To develop and validate a picosecond Differential Absorption Lidar (DIAL) system for range-resolved ammonia detection.
• To investigate the capability of the system for monitoring ammonia concentration profiles in combustion environments.
• To establish the detection limit and spatial resolution of the developed NH3 sensor.

Main Methods:

• Utilized a tunable picosecond laser source for ammonia detection.
• Employed Differential Absorption Lidar (DIAL) technique for remote sensing.
• Selected 212.2 nm (on-resonance) and 214.5 nm (off-resonance) wavelengths targeting the A(ν2 = 1) ← X(ν2 = 0) band.
• Recorded one-dimensional concentration profiles of ammonia.

Main Results:

• Achieved a detection limit of 40 ppm for ammonia.
• Demonstrated a spatial resolution of 16 cm for the measurements.
• Presented one-dimensional concentration profiles illustrating various ammonia distribution scenarios.

Conclusions:

• Picosecond DIAL is a viable technique for range-resolved, single-ended ammonia detection.
• The system provides high spatial resolution for monitoring ammonia in combustion.
• The developed method offers precise measurements crucial for optimizing combustion processes and reducing emissions.