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Module 3: Characteristics of Particles
This Module discusses industrially generated particles. The particle size distribution, which can be extremely broad, is primarily dependent on how the particles were created during the industrial process. This Module discusses some of the basic types of particle formation mechanisms active in air pollution sources as well as the basic collection mechanisms employed by particulate control devices.
Here are some benefits to understanding the characteristics of particles in air pollution control:
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The efficiency of the particle collection mechanisms strongly
depends on particle size.
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The particle size distribution of flue gas dictates the manner in
which air testing is performed.
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The particle size distribution of flue gas determines the operating
conditions necessary to collect the particles.
- Particle characteristics are important in determining the behavior of particles in the respiratory tract.
After completing this Module you will be able to do the following:
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Calculate the surface area and volume of spherical particles.
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Calculate the aerodynamic diameter and the terminal settling
velocity of particles.
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Distinguish between the different EPA particle categories with
respect to size and behavior.
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Determine the mass median particle diameter and standard deviation
of a lognormal particle size distribution.
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Describe the five main particle formation processes important at
air pollution sources and identify the particle size range
associated with each process.
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Describe the six main particle collection mechanisms used in
particulate control systems including factors that influence their
collection efficiency.
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Identify the particle size ranges where the particle collection
mechanisms are most efficient.
References
Additional information concerning particle behavior is available in the following publications.
Hinds, W. C. 1982. Aerosol Technology, Properties, Behavior, and Measurement of Airborne Particles. New York: Wiley-Interscience Publication.
Reist, P. C. 1982. Introduction to Aerosol Science. New York: Macmillian.