Aerosol Filtration

Dominique Thomas, Augustin Charvet, Nathalie Bardin-Monnier, Jean-Christophe Appert-Collin

• Publisher: ISTE Press - Elsevier
• Year: 2016
• ISBN:
  9780081021163
• Topic: Naturwissenschaften
• Subtopic: Strömungsmechanik

Filtration of aerosols is omnipresent in our daily lives, in areas as diverse as health, the protection of people and the environment, and air treatment inside buildings. However, the collection of particles within a filter media is not, contrary to popular belief, linked to a simple screen effect. The phenomena involved are much more complex and require the consideration of aerosol interactions, filter media and process conditions to select the best fiber filter for a given application. Aerosol Filtration, book for students, hygiene or process engineers, fibrous media manufacturers, designers, and filtration system suppliers or users addresses the filtration of aerosols in six chapters. These chapters cover physics and aerosol characterization, the fibrous media, and efficiency and filter clogging by solid or liquid aerosols, with special attention to the filtration of the nanoparticles.

• Analyses the behavior of fibrous media against solid and liquid aerosols
• Presents models of efficiency and pressure drop
• Introduces computing elements for estimating the lifetime of filters
• Provides guidance for designing filters and predicting their behavior over time

1

An Introduction to Aerosols

Dominique Thomas; Augustin Charvet

Abstract

The term aerosol first appeared around 1920 to designate the suspension, in a gaseous medium, of solid or liquid particles with negligible settling velocity. In air and under normal conditions, these correspond to particles smaller than 100 μm. Gives the dimensions of some of the impurities usually found in air with some comparative elements. An aerosol, by definition, refers to both the particles as well as the gas in which these particles are suspended. However, as a result of constant misuse, the term aerosol is often mistakenly used as a synonym for particles.

Keywords

Diameters; Diffusional parameter; Drag force; Equivalent diameter; Gaseous medium; Knudsen number; Mean free path; Nanostructured particles; Quasi-fractal particles

The term aerosol first appeared around 1920 to designate the suspension, in a gaseous medium, of solid or liquid particles with negligible settling velocity. In air and under normal conditions, these correspond to particles smaller than 100 μm. Figure 1.1 gives the dimensions of some of the impurities usually found in air with some comparative elements. An aerosol, by definition, refers to both the particles as well as the gas in which these particles are suspended. However, as a result of constant misuse, the term aerosol is often mistakenly used as a synonym for particles.

Figure 1.1 Orders of magnitude of size for some particles

In the field of air-quality surveillance, suspended particles in air are divided into different PMx classes (PM, particulate matter) based on their aerodynamic diameter x (see section 1.4.5):

– PM 10: particles with an aerodynamic diameter smaller than 10 μm;

– PM 2.5: particles with an ...