For an ideal plug flow reactor, the value of Peclet number is_______________?

Related Mcqs:

1. The following gas phase reaction is taking place in a plug flow reactor. A stoichiometric mixture of A and B at 300 K is fed to the reactor. At 1 m along the length of the reactor, the temperature is 360 K. The pressure drop is negligible and an ideal gas behaviour can be assumed. Identify the correct expression relating the concentration of A at the inlet (CA0), concentration of A at 1m (CA) and the corresponding conversion of A (X) ?

   A. CA = 1.2 CA0 (1 – X)/(1 – 0.33X)
   B. CA = 1.2 CA0 (1 – X)/(1 – 0.5X)
   C. CA = 0.83 CA0 (1 – X)/(1 – 0.33X)
   D. CA = 0.83 CA0 (1 – X)/(1 – 0.5X)

2. ‘N’ plug flow reactors in series with a total volume ‘V’ gives the same conversion as a single plug flow reactor of volume ‘V’ for _______________ order reactions?

   A. First
   B. Second
   C. Third
   D. Any

3. The gas phase reaction 2A ⇌ B is carried out in an isothermal plug flow reactor. The feed consists of 80 mole % A and 20 mole % inerts. If the conversion of A at the reactor exit is 50%, then CA/CA0 at the outlet of the reactor is _______________________?

   A. 2/3
   B. 5/8
   C. 1/3
   D. 3/8

4. With increase in the order of reaction (for all positive reaction orders), the ratio of the volume of mixed reactor to the volume of plug flow reactor (for identical feed composition, flow rate and conversion)?

   A. Increases
   B. Decreases
   C. Remain same
   D. Increases linearly

5. A pollutant P degrades according to first order kinetics. An aqueous stream containing P at 2 kmole/m3 and volumetric flow rate 1m3 /h requires a mixed flow reactor of volume V to bring down the pollutant level to 0.5 kmole/m3. The inlet concentration of the pollutant is now doubled and the volumetric flow rate is tripled. If the pollutant level is to be brought down to the same level of 0.5 k.mole/m3, the volume of the mixed flow reactor should be increased by a factor of_______________?

   A. 7
   B. 6
   C. 3
   D. 7/3

6. For identical flow rate, feed composition and for elementary first order reactions, ‘N’ equal sized mixed reactors in series with a total volume ‘V’ gives the same conversion as a single plug flow reactor of volume ‘V’ for constant density systems. This is true, when the value of ‘N’ is ___________________?

   A. 1
   B. > 1
   C. ∞
   D. ≥ 1

7. The reaction A → B is conducted in an adiabatic plug flow reactor (PFR). Pure A at a concentration of 2 kmol/m3is fed to the reactor at the rate of 0.01 m3 /s and at a temperature of 500 K. If the exit conversion is 20%, then the exit temperature (in k) is (Data: Heat of reaction at 298 K = – 50000 kJ/ kmole of A reacted Heat capacities CPA = CPB = 100kJ/kmole. K (may be assumed to be independent of temperature)) ?

   A. 400
   B. 500
   C. 600
   D. 1000

8. The size of plug flow reactor (PFR) for all positive reaction orders and for any given duty, is _____________________ that of mixed reactor?

   A. Greater than
   B. Equal to
   C. Smaller than
   D. Unpredictable from the data

9. A reversible liquid phase endothermic reaction is to be carried out in a plug flow reactor. For minimum reactor volume, it should be operated such that the temperature along the length ?

   A. Decreases
   B. Increases
   C. Is at the highest allowable temperature throughout
   D. First increases and then decreases

10. Which of the following is a characteristic of an ideal plug flow reactor ?

    A. Axial dispersion
    B. Flat velocity profile
    C. Uniform mixing
    D. None of these