For the same system, if the same liquid used in an absorber is decreased, the tower height will__________________?

Related Mcqs:

1. H2S is being absorbed in a gas absorber unit. The height of the transfer unit based on the overall mass transfer coefficient on the gas side is 0.4 m. The equilibrium data is given by, y = 1.5 x. The bulk concentration of H2S has to be reduced from 0.05 to 0.001 mole fraction in the gas side. The height of the tower (in meters) corresponding to an operating line given by, y = 5x + 0.001 is ______________________?

   A. 2.0
   B. 1.56
   C. 1.0
   D. 0.56

2. Acetone is to be removed from air in an isothermal dilute absorber using pure water as solvent. The incoming air contains 5 mole% of acetone (yin = 0.05). The design equation to be used for obtaining the number of trays (N) of the absorber is, N+2 = 6 log (yin/yout).For 98% recovery of acetone, the number of trays required is/are ?

   A. 4
   B. 8
   C. 9
   D. 10

3. A natural draft cooling tower is filled with wooden grids, which covers about _________________ percent of the tower height?

   A. 10-15
   B. 30-40
   C. 70-80
   D. 90-100

4. At the same gas flow rate, the pressure drop in a packed tower being irrigated with liquid _______________ that in dry packed tower ?

   A. Is greater than
   B. Is lower than
   C. Is same as
   D. Cannot be predicted as data are insufficient

5. In a packed tower, the value of HETP equals HTUOG, when the equilibrium and the operating lines are (where, HETP = height equivalent to a theoretical plate HTUOG = overall gas phase height of a transfer unit) ?

   A. Straight
   B. Parallel
   C. Both A. & B.
   D. Neither A. nor B.

6. For the gas absorption, the height of a transfer unit, based on the gas phase is given by (G: superficial molar gas velocity, L: superficial molar liquid velocity, FG: mass transfer co-efficient, moles/m2, a: interfacial area per unit volume of tower) ?

   A. G/(FG . a)
   B. FG/(G . a)
   C. (G . a)/FG
   D. L/(FG . G)

7. The minimum liquid rate to be used in an absorber corresponds to an operating line__________________?

   A. Of slope = 1
   B. Of slope = 0.1
   C. Tangential to the equilibrium curve
   D. None of these

8. The minimum liquid rate to be used in an absorber corresponds to an operating line_______________________?

   A. Of slope = 1
   B. Of slope = 0.1
   C. Tangential to the equilibrium curve
   D. None of these

9. If G = insoluble gas in gas stream and L = non-volatile solvent in liquid stream, then the slope of the operating line for the absorber is___________________?

   A. L/G
   B. G/L
   C. Always < 1
   D. None of these

10. Tower diameter may be decreased by__________________?

    A. Using higher reflux ratio
    B. Use of increased tray spacing
    C. Increasing the liquid flow rate
    D. Increasing the vapour flow rate