A. Constant residence time
B. Variation in extent of reaction and properties of the reaction mixture with time
C. Variation in reactor volume
D. Very low conversion
Related Mcqs:
- A second order liquid phase reaction, A → B, is carried out in a mixed flow reactor operated in semi batch mode (no exit stream). The reactant A at concentration CAF is fed to the reactor at a volumetric flow rate of F. The volume of the reacting mixture is V and the density of the liquid mixture is constant. The mass balance for A is_______________________?
A. d(VCA)/dt = -F (CAF – CA) – kCA2V
B. d(VCA)/dt = F (CAF – CA) – kCA2V
C. d(VCA)/dt = -FCA – kCA2V
D. d(VCA)/dt = FCAF – kCA2V - Second order consecutive irreversible reaction as shown in the bellow figure, were carried out in a constant volume isothermal batch reactor with different initial feed compositions. Reactor temperature was same in all the cases. In experiments where the ratio of concentration of B to that of A in the initial feed was less than 0.5, the concentration of B increased first, reached a maximum and then declined with time. However, for all experiments where this concentration ratio was 0.5 or above, concentration of B decreased monotonically with time right from the beginning. What is the ratio of the two rate constants (k1/k2) ?
A. 1/4
B. 1/2
C. 2
D. 4 - 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) - 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 - In case of a _____________ reactor, the composition in the reactor and at the exit of the reactor is the same ?
A. Semi-batch
B. Tubular
C. Batch
D. Back-mix - Pure ethanol vapor is fed to a reactor packed with alumina catalyst, at the rate of 100 kmole / hr. The reactor products comprise: ethylene: 95 kmole / hr, water vapour: 97.5 k mole / hr and diethyl ether: 2.5 kmole/hr. The reactions occuring can be represented by: C2H5OH → C2H4 + H2O 2C2H5OH → C2H5 – O – C2H5 + H2O The percent conversion of ethanol in the reactor is________________?
A. 100
B. 97.5
C. 95
D. 2.5 - A batch reactor suffers from following disadvantage ?
A. Poor product quality control
B. High labour and handling cost
C. High shutdown time requirement for emptying, cleaning and refilling
D. All A., B. and C. - The reaction A → B is conducted in an isothermal batch reactor. If the conversion of A increases linearly with holding time, then the order of the reaction is __________________?
A. 0
B. 1
C. 1.5
D. 2 - For an isothermal variable volume batch reactor, the following relation is applicable for a first order irreversible reaction?
A. XA = k . t
B. [CA0/(1 + εA XA)] (dXA/dt) = k
C. -ln(1 – XA) = kt
D. εA . ln (1 – XA) = k . t - A batch reactor is_______________?
A. Suitable for gas-phase reactions on commercial scale
B. Suitable for liquid phase reactions involving small production rate
C. Least expensive to operate for a given rate
D. Most suitable for very large production rate
