Filtration rate through a filter cake is proportional to (where, S = filtering surface, R = specific cake resistance, $$\mu $$ = viscosity of the filtrate)

A rotary drum filter with 30% submergence is used to filter concentrated aqueous slurry of calcium carbonate containing 15lb of solids per cubic foot of water. The pressure–drop is 2011Hg. If the filter cake contains 50% mixture (wet basis), calculate the filter area required to filter 10 gal/min of slurry. The filter cycle time is 5 min. The specific cake resistance depends on the pressure–drop as: α (ft/lb) = α (Δp)0.26, where α = 2.90×1010 Viscosity of the filtrate = 6.72×10-4 lb/ft-s. Density of calcium carbonate = 168.8 lb/ft3. Neglect filter medium resistance.

A

≅ 88 ft2

B

= α (Δp)0.26, where α = 2.90×1010 Viscosity of the filtrate = 6.72×10-4 lb/ft-s. Density of calcium carbonate = 168.8 lb/ft3. Neglect filter medium resistance. a) ≅ 88 ft2 [ ≅ 86 ft2

C

≅ 82 ft2

D

≅ 90 ft2

Five cakes in a shop are placed in a row on a shelf. Cake T is to the immediate left of Cake R and to the immediate right of Cake U. Cake M is to the right of Cake R. Cake B is the neighbour of Cake R and Cake M. Which cake is placed in the middle of the shelf?

A

Cake T

B

Cake R

C

Cake M

D

Cake B

Filtrate flow rate in case of a rotary drum vacuum filter (in which Rm c) is proportional to __________ and the cycle time (where, μ = filtrate viscosity Rm = filter medium resistance Rc = cake resistance ).

A

√μ

B

1/√μ

C

1/μ

D

1/μ²

Filtrate flow rate in case of a rotary drum vacuum filter (in which R_m c) is proportional to __________ and the cycle time (where, $$\mu $$ = filtrate viscosity, R_m = filter medium resistance, R_c = cake resistance ).

A

$$\sqrt \mu $$

B

$$\frac{1}{{\sqrt \mu }}$$

C

$$\frac{1}{\mu }$$

D

$$\frac{1}{{{\mu ^2}}}$$

Statement 1: Filter cake increases the efficiency of filtration. Statement 2: Filter aid is added to the filter cake when the filter cake is the desired product.

A

True, False

B

True, True

C

False, False

D

False, True

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

Precoated on the filter medium prior to filtration

C

Separated from the cake by dissolving solids or by burning it off

D

All of the above

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

Precoated on the filter medium prior to filtration

C

Separated from the cake by dissolving solids or by burning it off

D

All of the above

Which of the following statements about filtration medium resistance are correct? Statement 1: Filtration resistance results in frictional drag. Statement 2: Filtrate velocity is directly proportional to pressure difference.

A

True, False

B

True, True

C

False, True

D

False, False

A foil is to be put as shield over a cake (circular) in a shape such that the heat is even along any diameter of the cake. Given that the heat on cake is proportional to the height of foil over cake, the shape of the foil is given by

A

f(x, y) = sin(y/x)x2 + xy

B

f(x, y) = x2 + y3

C

f(x, y) = x2y2 + x3y3

D

not possible by any analytical function

A straight line is obtained on plotting reciprocal of filtration rate vs. the volume of filtrate for __________ flow of filtrate.

A

Compressible cakes and laminar

B

Incompressible cake and laminar

C

Compressible cake and turbulent

D

Incompressible cake and turbulent

Filtration rate through a filter cake is proportional to (where, S = filtering surface, R = specific cake resistance, $$\mu $$ = viscosity of the filtrate)

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