A centrifugal filtration unit operating at a rotational speed of w has inner surface of the liquid (density ρL) located at a radial distance R from the axis of rotation. The thickness of the liquid film is δ and no cake is formed. The initial pressure drop during filtration is ___________________?

Related Mcqs:

1. The basic filtration equation is given as dt/dV = (μ/A ΔP). [(α .CV/A) + Rm], where, V is volume of the filtrate; A is the filtration area, a is specific cake resistance, μ is viscosity of the filtrate, and C is the concentration of the solids in the feed slurry. In a 20 minutes constant rate filtration, 5 m3 of filtrate was obtained. If this is followed by a constant pressure filtration, how much more time in minutes, it will take for another 5 m3 of filtrate to be produced? Neglect filter medium resistance, Rm; assume incompressible cake ?

   A. 10
   B. 20
   C. 25
   D. 30

2. Filtration rate through a filter cake is proportional to (where, S = filtering surface R = specific cake resistance μ = viscosity of the filtrate) ?

   A. S
   B. 1/R
   C. 1/μ
   D. All A., B. & C.

3. Filter aids like asbestos, kieselguhr, diatomaceous earth etc. are used to increase the porosity of the final filter cake & reducing the cake resistance during filtration. Filter aid is_______________?

   A. Added to the feed slurry
   B. Pre-coated on the filter medium prior to filtration
   C. Separated from the cake by dissolving solids or by burning it off
   D. All A, B. & C.

4. The specific cake resistance for incompressible sludges is (where ΔP = pressure drop over cake)__________________?

   A. ∝ ΔP
   B. ∝ 1/ ΔP
   C. ∝ √ΔP
   D. Independent of ΔP

5. With increase in the pressure drop across the cake, the specific cake resistance for the compressible sludge________________?

   A. Increases
   B. Decreases
   C. Remains constant
   D. Increases linearly

6. The cake resistance increases steadily with the time of filtration in a plate and frame filter employing constant ______________ filtration?

   A. Rate
   B. Pressure
   C. Both A. & B.
   D. Neither A. nor B.

7. Filtration operation carried out by continuous increase of the inlet pressure of slurry, is called the _____________ filtration?

   A. Constant rate
   B. Varying pressure
   C. Varying rate
   D. Constant pressure

8. Theoretical capacity of crushing rolls in tons/hr is given by (where, V = peripheral velocity, m/sec. W = width of rolls, m Dr = distance between rolls ρ = density of material to be crushed, kg/m3 here, V =πND where, N = speed of the rolls in rotation per second (rps) D = diameter of rolls, m) ?

   A. 3.6 V.W.Dr.ρ
   B. 3.6 V.W. ρ
   C. 3.6 W.Dr.ρ
   D. 3.6 V.W.Dr/ρ

9. Addition of filter aid to the slurry before filtration is done to _______________ of the cake?

   A. Increase the porosity
   B. Increase the compressibility co-efficient
   C. Decrease the porosity
   D. Decrease the compressibility co-efficient

10. Range of compressibility co-efficient of the commercial compressible cake obtained in filtration operation is_____________________?

    A. 0.01 to 0.1
    B. 0.1 to 0.3
    C. 0.2 to 0.8
    D. 0.2 to 0.4