Question

In an electrostatic precipitator the: _________

a. Discharge electrode is negatively charged
b. Ash falls unaided into the bottom hopper
c. Collector plates and electrodes are both positively charged
d. Particles receive a positive charge

Answer 1

In an electrostatic precipitator, particles receive a positive charge from the first grid and are collected on the negatively charged plates. This charging and collecting process is efficient in removing particulates from the airstream, cleaning the air significantly.

Step-by-step explanation:

In an electrostatic precipitator, airborne particles are given a charge before they pass through grids that have an opposite charge. As explained with Figure 18.42, the first grid charges the particles, which are then attracted and collected by the second grid. This mechanism allows for the efficient removal of particulate matter from an airstream, thereby cleaning the air and reducing pollution emissions, as seen in the absence of smoke from a power plant using this technology.

Regarding the specific question, the particles receive a positive charge from the first grid and are then attracted to the negatively charged plates in the electrostatic precipitator. Collector plates are usually negatively charged to attract the positively charged particles, and these particles can then fall into the bottom hopper, sometimes aided by a mechanical rapping system that dislodges the collected particles from the plates.