Trial Question For the following particle size distribution, calculate the efficiency of a Lapple conventional cyclone with a body diameter of 0.5m. the particulate density= 1200kg/m³, gas density= 0.9kg/m³, gas velocity=0.06kg/m-hr, inlet gas velocity=25m/s. Assuming that the efficiency of the above cyclone is 90%, Calculate the new efficiency if the (a) inlet gas velocity reduces to 15m/s, (b) particulate density changes to 1000kg/m³. Size Range, nm 0-4 4-10 10-20 20-40 40-80 >80 Mass percent in size Range 3.0 10.0 30.0 40.0 15.0 2.0

Calculate the pressure drop for the cyclone of Problem 4,2, assuming K =14,

The three statements below all refer to standard single-barrel reverse flow cyclones used to remove particulate matter from air. For each statement, indicate whether it is True or False and explain your reasoning. a) If a cyclone has a collection efficiency of 25% for a specific-sized particle, then it can be expected always to have a collection efficiency of 50% if the particle size doubles, assuming all else remains constant. b) If a cyclone has a collection efficiency of 25% for a particle having a specified density, then it can be expected always to have a collection efficiency of 50% if the particle density doubles, assuming all else remains constant. c) To a single decimal place, the effective number of turns made in traversing a standard cyclone is always 37.7, independent of the cyclone size and air flow rate into the cyclone.

What diameter would a circular clarifier have to be to remove 50 μm particles with 75% efficiency from a 4 MGD (million gallon per day) flow?  Assume the particle specific gravity is 1.5 and the temperature is 10°C.  Answer: 18 m