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 ______________________?

Related Mcqs:

1. 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)

2. Experiments were conducted to determine the flux of a species A in a stagnant medium across a gas-liquid interface. The overall mass transfer co-efficient based on the liquid side for dilute systems for the above was estimated to be 4 × 10-3 kg mole/m2.s. The equilibrium data for the system is given as y = 2x. The flux across the interface (in kg mole/m2 .s) for bulk concentrations of A in gas phase and liquid phase as y = 0.4 and x = 0.01 respectively is _________________________?

   A. 5.6 × 10-4
   B. 8.5 × 10-4
   C. 5.6 × 10-3
   D. 8.5 × 10-3

3. 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.

4. The relation among various mass transfer co-efficients (M.T.C) for ideal gases is given by (where, Kc & Km are M.T.C. for equimolar counter diffusion with concentration & mole fraction respectively as the driving force. and, Kp= M.T.C. for diffusion of a gas through a stagnant inert gas with pressure as driving force) ?

   A. Kc = Kp = Km
   B. Kc = Kp/RT = Km . RT/P
   C. Kc = Kp . RT = Km . RT/p
   D. None of these

5. 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

6. 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

7. 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

8. 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

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

   A. Increase
   B. Decrease
   C. Remain unaffected
   D. Decrease or increase; depends on the type of liquid

10. Out of the following gas-liquid contacting devices, for a given set of operating conditions, gas pressure drop is the least in ______________ tower?

    A. Wetted wall
    B. Bubble cap
    C. Perforated tray
    D. Packed