Question

For the removal of sub-micron particulate matter (\(\lt 1~\mu\mathrm{m}\)) from flue gases, which of the following devices generally provides the highest collection efficiency?

• A. Electrostatic precipitator
• B. Cyclone separator
• C. Gravity settling chamber
• D. Wet scrubber

Hint:

Efficiency of particulate control devices: \[ \boxed{ \text{ESP} \gt \text{Wet Scrubber} \gt \text{Cyclone Separator} \gt \text{Gravity Settling Chamber} } \] ESPs are best suited for very fine particles.

Answer 1

The Correct Option is A

Step 1: Think about how each device captures particles.
Gravity settling chambers and cyclone separators rely on particle weight and inertia, which works well only for coarse particles.
Step 2: See why sub-micron particles need a different approach.
Particles smaller than $1\ \mu\mathrm{m}$ are too light for gravity or inertial forces to catch effectively, so a different collection mechanism is needed.
Step 3: Bring in the electrostatic precipitator.
An ESP charges the particles electrically and then pulls them onto collector plates using an electric field, a force that works even on very fine and sub-micron dust, giving it the highest collection efficiency among the listed devices.
\[ \boxed{\text{Electrostatic precipitator}} \]