Which of the following quantities need not be fixed before starting the design of a cocurrent absorber ?

Related Mcqs:

1. 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

2. 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

3. 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

4. The slope of the operating line for a single component co-current absorber when plotted in terms of mole ratio units is_____________________?

   A. 0
   B. ∞
   C. -ve
   D. +ve

5. For a single component absorber, the operating line is straight only when plotted in term of ______________ units?

   A. Partial pressure
   B. Mole ratio
   C. Mole fraction
   D. None of these

6. For an absorber, both equilibrium and operating line will be straight for _______________________?

   A. Concentrated solution and non-isothermal operation
   B. Dilute solution and non-isothermal operation
   C. Dilute solution and isothermal operation
   D. Concentrated solution and isothermal operation

7. Desirable value of absorption factor in an absorber is___________________?

   A. 1
   B. < 1
   C. > 1
   D. 0.5

8. The operating line for an absorber is curved, when plotted in terms of _______________________?

   A. Mole fractions
   B. Mole ratios
   C. Partial pressure
   D. Mass fractions

9. In an absorber, HETP does not vary with the____________________?

   A. Flow rate of liquid
   B. Flow rate of gas
   C. Type and size of packing
   D. None of these

10. 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