Conventional and Alternative Power Generation

5Control of Particulates

5.1 Overview

The term particulate matter (PM) or particulates describes solid or liquid particles released into the atmosphere from either man‐made or natural sources.

At low levels in the atmosphere, particulates are harmful to human health whilst at higher atmospheric levels they may alter the earth's heat balance due to selective absorption and reflection of electromagnetic radiation.

Natural particulate sources include volcanoes and sea spray.

Significant man‐made sources include solid fuel, for example, coal or biomass‐fired electricity generation plants and diesel engines.

This chapter will introduce some of the significant parameters associated with particle dynamics and particle capture and will go on to apply these to common particulate collection systems such as cyclones and electrostatic precipitators.

Learning Outcomes

• To understand the nature of particulates.
• To be familiar with basic particle collection efficiency and associated performance definitions.
• To be familiar with basic particle forces and associated dimensionless parameters.
• To be familiar with particulate collection devices such as gravity settlers, cyclones, ESPs etc., and to use the mass conservation law to model performance.

5.2 Some Particle Dynamics

5.2.1 Nature of Particulates

The most commonly used unit for expressing particulate concentration in the environment is weight (of particulate) per unit volume (of environment), measured in micrograms per cubic metre (µg/m³); however, particulate ...