A. Increases
B. Decreases
C. Remain constant
D. None of these
Related Mcqs:
- During washing of filter at the end of constant pressure filtration, the rate of washing equals the rate of filtration___________________?
A. At time zero
B. At the end of filtration
C. When half the filtrate has been obtained
D. At the end of filtration, but decreases with time subsequently - 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. - In washing type plate and frame filter press, the ratio of washing rate to the final filtrate rate is__________________?
A. 4
B. 1/4
C. 1
D. 1/2 - 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 - 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 - 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. - 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 - The porosity of a compressible cake is _____________________?
A. Minimum at the filter medium
B. Minimum at the upstream face
C. Maximum at the filter medium
D. Same throughout the thickness of cake - During the washing of cake_________________?
A. All the resistances are constant
B. Filter medium resistance increases
C. Filter medium resistance decreases
D. Cake resistance decreases - 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 ___________________?
A. ½w2 . R2 . ρL
B. ½w2 . δ2 . ρL
C. ½w2 . δρL (2R + δ)
D. ½w2 . R . ρL(R + 2δ)
