Aerosol gas exchange system (AGES) for nanoparticle sampling at elevated temperatures: Modeling and experimental...

Area of Science:

• Aerosol science and engineering
• Environmental engineering
• Chemical engineering

Background:

• Nanoparticle sampling at elevated temperatures presents challenges for gas removal and particle loss.
• Existing systems may require particle dilution, potentially affecting measurement accuracy.
• Efficient gas exchange is crucial for accurate characterization of aerosols in various industrial and environmental applications.

Purpose of the Study:

• To develop, model, and characterize an aerosol gas exchange system (AGES) for nanoparticle sampling at elevated temperatures.
• To evaluate the gas exchange efficiency and particle loss characteristics of the AGES.
• To provide a predictive model for optimizing AGES design for specific applications.

Main Methods:

• Development and mathematical modeling of the aerosol gas exchange system.
• Laboratory characterization using inert gases (molecular masses 18–135 u) and gaseous sulfuric acid.
• Experimental measurement of particle losses for 6 nm and down to 1.2 nm particles.

Main Results:

• The AGES achieved over 90% exchange efficiency for light compounds at tested flow rates.
• Increased residence time is necessary for high removal efficiencies of larger molecules.
• Very limited particle losses (<5% for 6 nm particles) were observed; diffusional losses for particles down to 1.2 nm were quantified.
• Experimental results closely matched the derived model predictions.

Conclusions:

• The AGES demonstrates effective nanoparticle sampling with controlled gas exchange and minimal particle loss.
• Gas exchange efficiency and particle loss are inversely related due to diffusion; optimization is application-dependent.
• The developed model serves as a valuable tool for redesigning and optimizing the AGES, potentially eliminating the need for particle dilution and enhancing aerosol measurement quality.