Alternative and Renewable Energy - Advanced Materials ...

Spiral 2: 3/28/2011Department of Defense Energy HandbookAlternative and Renewable Energy Options for DoD Facilities and Baseskey consideration; it must be high in order for this collection method to be effective. Resistivity is not afactor with wet ESPs.There are five major particulate control devices: mechanical collectors, baghouses, wet scrubbers, dryscrubbers, and electrostatic precipitators. These are described briefly in the following sections. Asimplified process for selecting an appropriate particulate control device is provided in Figure 143.Figure 143. Process for selecting a particulate control system. 26810.5.4.1.1 Mechanical CollectorsThe most common form of mechanical collector is a cyclone, often referred to as a centrifugal dustcollector. These collectors collect large particles and as the particle size decreases, the efficiency of thecollector decreases. Cyclones create a double vortex to separate the particles from the gas. In thisenvironment the inert gases spiral downward to create a centrifugal force that causes the particles tomove toward the wall. As the gas changes direction and spiral upward toward the exit these particles falltoward the bottom.The diameter of the cyclone has an impact on the efficiency. As the diameter increases, the efficiencydecreases because the particles must travel further before reaching the wall. Multiple cyclones used inparallel can mitigate this issue, as illustrated in Figure 144. 248235