The collection efficiency of cyclone separators increases with: 1) Decreasing particle size 2) Increasing particle density 3) Decreasing gas velocity 4) Increasing number of gas revolutions 5) Increasing cyclone diameter Which of the above statements are correct?

Option 2 : 2 and 4 only

Explanation:

Cyclone seperator:

• A cyclone separator is a device that separates particles from a gas stream using centrifugal force.
• The solid particles which are denser than the gas, have a high centrifugal force, which directs them to the walls, where they collide and lose momentum and get separated easily.
• Hence, cyclone separator efficiency increases with increase in density of particles and size of particle.
• Also, with increase in speed of revolution, the gas flow rate increases and it creates a swirling movement inside the separator, because of which the particles get easily separated after striking the walls.