Hot filter/impinger and dilution sampling for fine particulate matter characterization from ferrous metal casting...

Area of Science:

• Environmental Science
• Industrial Hygiene
• Chemical Engineering

Background:

• Particulate matter (PM) emissions from industrial processes are a key environmental concern.
• Accurate measurement of fine particulate matter (PM2.5) is crucial for health and regulatory purposes.
• Ferrous iron metal casting involves multiple stages that can release PM.

Purpose of the Study:

• To compare two distinct stack-sampling methodologies for collecting PM emissions from ferrous iron metal casting.
• To quantify the contribution of different casting stages, particularly shakeout, to PM emissions.
• To evaluate the impact of sampling methods on the measured mass and composition of PM2.5.

Main Methods:

• Utilized a hot filter/cold impinger sampling train and a dilution sampler to collect PM from casting processes.
• Collected samples during molten iron pouring, cooling, shakeout, and post-shakeout cooling stages.
• Analyzed the mass, composition, and aerodynamic diameter of collected particulate matter.

Main Results:

• The shakeout process was identified as a major contributor to PM emissions compared to pouring and cooling.
• The hot filter/impinger method yielded significantly higher PM2.5 mass emissions (3.4–4.7 lb/t) than the dilution method (0.8–1.8 lb/t).
• A substantial portion of PM captured by impingers (32–38% of total suspended particles) was organic and likely dissolved gases, causing a 2-4x positive bias in PM2.5 measurements.

Conclusions:

• The choice of sampling methodology significantly impacts PM2.5 emission estimates in metal casting.
• Impinger-captured PM, often composed of dissolved gases, can lead to overestimation of condensable PM2.5.
• Accurate characterization of PM emissions requires careful consideration of sampling train components and potential interferences.