Overall mass transfer co-efficient in case of absorption of __________ in water is based on the gas film co-efficient only, as the mass transfer process is gas film (phase) controlling ?

Related Mcqs:

1. In a shell and tube heat exchanger, the overall heat transfer co-efficient is proportional to the tube side (volumetric flow rate)0.8. This is valid, only when the ratio of the tube side film resistance to the total resistance is almost equal to____________________?

   A. ∞
   B. 1
   C. 20.8
   D. 2

2. Height equivalent to a theoretical plate (HETP) is the height of packing that will give the same separation as one theoretical plate in gas-liquid mass transfer operations like distillation, absorption/stripping and humidification/dehumidification. HETP which is experimentally determined, depends upon the_______________?

   A. Flow rates of each fluid
   B. Type and size of packing
   C. Concentration of each fluid
   D. All A, B. & C.

3. Pressure drop (Δp) and the superficial gas mass velocity (G) in case of packed absorption tower operating in the preloading range are related as_________________?

   A. Δp = G
   B. Δp = G0.5
   C. Δp = G2
   D. Δp = 1/G0.6

4. Heat transfer co-efficient, hG(Kcal/hr.m2 .°C) and mass velocity of air, G (kg/hr.m2 ) for air flow parallel to the surface in case of constant drying rate in batch drying is related as hG = 0.0176G0.8. But when the flow of air perpendicular to the surface is encountered, this equation changes to ____________________?

   A. hG = 1.004G0.37
   B. 1.004G0.8
   C. hG = 0.0176G0.37
   D. 0.0176G1.37

5. A single pass air heater is connected to a two pass unit. For the air flow rate and other conditions remaining the same, the film heat transfer co-efficient for air will vary in the ratio of_________________?

   A. 2
   B. 20.8
   C. 20.2
   D. None of these

6. The operating velocity in the absorption tower is usually 40-50% of the flooding velocity. Packed absorption towers are normally designed for a pressure drop of about _________________ mm of water column per metre height of packing?

   A. 1-5
   B. 20-40
   C. 100-150
   D. 1000-1500

7. In case of a shell and tube heat exchanger, the effect of L/D on inside film heat transfer coefficient (hi) vanishes after a Reynold number of_____________?

   A. 1000
   B. 3000
   C. 5000
   D. 10000

8. For identical situation, condensing film coefficient in case of a horizontal condenser is almost ______________ the value expected in case of vertical condenser?

   A. Half
   B. Twice
   C. Thrice
   D. Five times

9. Shell side heat transfer co-efficient in case of square pitch as compared to the triangular pitch under similar condition of fluid flow and tube size is_____________?

   A. More
   B. Same
   C. Less
   D. Twice

10. Overall distillation column efficiency for most of the refinery columns can be given by (for μ = 0.07 – 1.4 cp and relative volatility < 4) (where ε = overall column efficiency, % μ = molal average viscosity of feed at average column temperature and pressure, cp Δp = pressure drop per tray, psi) ?

    A. η = 17 – 61.1 log μ
    B. η = 24.6 (Δp/μ)
    C. η = 1.66 – 0.25 log μ
    D. η = 0.25 log μ – 1.67