A. Space time is equivalent to holding time for constant density systems
B. Composition throughout the reactor remains same
C. Exit stream has the same composition as the fluid within the reactor
D. All A., B. and C.
Related Mcqs:
- 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 - The space time is equivalent to the holding time in a steady state mixed reactor for_____________________?
A. Non-isothermal gas reaction
B. Variable fluid density systems
C. Constant fluid density systems
D. Gas reactions with changing number of moles - For a mixed flow reactor operating at steady state, the rate of reaction is given by______________?
A. (FA0/V) – (dCA/dt)
B. (FA0/V) + (dCA/dt)
C. (FA0/V) XA
D. -(dCA/dt) - 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) - In an ideal P.F.R. at steady state conditions ___________________?
A. The composition of reactants remains constant along a flow path
B. The conversion of the reactant varies from point to point along a flow path
C. There is no lateral mixing of fluid
D. There may be diffusion along the flow path - 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 - An irreversible aqueous phase reaction, A + B → P, is carried out in an adiabatic mixed flow reactor. A feed containing 4kmole/m3 of each A and B enters the reactor at 8m3 /hr. If the temperature of the exit stream is never to exceed 390 K, what is the maximum inlet feed temperature allowed? Data: Heat of reaction = – 50 kJ/mole Density of the reacting mixture = 1000kg/m3 Specific heat of reacting mixture = 2kJ/kg.K The above data can be assumed to be independent of temperature and composition?
A. 190
B. 290
C. 390
D. 490 - 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 - 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 - An isothermal aqueous phase reversible reaction, P ⇌ R, is to be carried out in a mixed flow reactor. The reaction rate in k.mole/m3 .h is given by, r = 0.5CP – 0.125CR. A stream containing only P enters the reactor. The residence time required (in hours) for 40% conversion of P is_________________?
A. 0.80
B. 1.33
C. 1.60
D. 2.67
