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The reaction A → B is conducted in an adiabatic plug flow reactor (PFR). Pure A at a concentration of 2 kmol/m<sup>3</sup> is fed to the reactor at the rate of 0.01 m<sup>3</sup>/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 C<sub>PA</sub> = C<sub>PB</sub> = 100 kJ/kmole. K (may be assumed to be independent of temperature))

Correct Answer: 600

An irreversible aqueous phase reaction, A + B → P, is carried out in an adiabatic mixed flow reactor. A feed containing 4 kmole/m3 of each A and B enters the reactor at 8 m3/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 = 1000 kg/m3, Specific heat of reacting mixture = 2 kJ/kg.K)
The above data can be assumed to be independent of temperature and composition.

Pick out the wrong statement below:
I. For the same conversion, the holding time required in a batch reactor, is always equal to the space time required in a PFR.
II. Two mixed reactors of unequal size are available for producing a specified product, formed by a homogenous second order reaction. To achieve maximum production rate, the smaller reactor should be placed in series before the larger reactor.
III. Arrehenius equation describing the effect of temperature on rate constant is given by, $${\text{K}} = {\text{A}}.{{\text{e}}^{ - \frac{{{\text{Ea}}}}{{{\text{RT}}}}}}$$
IV. The mechanism for the decomposition of CH3CHO into CH4 and CO in presence of I2 is:
CH3CHO + I2 → CH3I + HI + CO; slow
CH3I + HI → CH4 + I2; fast
Then the rate of disappearance CH3CHO is equal to K.CCH3l.CHl and acts as a catalyst.

In a batch process, the reaction takes place in the presence of an acid medium. The acid is drained from the reaction vessel at the rate of 15ml/s as a result of the density difference of the acid from the reacting component. To avoid wastage of acid, it is recycled to an acid tank which has 1000 L capacity. The acid drained from the reaction vessel, picks up 50 g/L solids from the reactor. Acid is fed once again to the process from acid tank. When the process is started, the acid is almost pure in the tank as a result of filtration. As the reaction proceeds, acid in the tank gets more and more contaminated with the solids. The concentration of the solids should not exceed 100 g/L from the process point of view. The batch time is 16h. Estimate whether the concentration of the solids will exceed 100g/L during the batch reaction.

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 $$\frac{{{{\text{C}}_{\text{A}}}}}{{{{\text{C}}_{{{\text{A}}_{\text{0}}}}}}}$$  at the outlet of the reactor is

The fresh feed to an ammonia synthesis reactor contains nitrogen, hydrogen and 2.0 mole per cent inerts. The molar ratio of H2:N2 is 3:1. The product stream consists of pure ammonia. Since conversion in the reactor is only 15%, a recycle stream is used and in order to avoid build-up of inerts, a purge stream is withdrawn. The rate of purge stream is adjusted to keep inert concentration in the recycle stream at 8 mole per cent. For a fresh feed rate of 100 moles/hr. Note that recycle stream contains only nitrogen, hydrogen and inerts. The N2:H2 ratio of 1:3 is maintained in every process stream, and calculate the moles of nitrogen entering the reactor and in the recycle stream?

For the liquid phase zero order irreversible reaction A → B, the conversion of A in a CSTR is found to be 0.3 at a space velocity of 0.1 min-1. What will be the conversion for a PFR with a space velocity of 0.2 min-1?
(Assume that all the other operating conditions are the same for CSTR and PFR.)

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)

For the reaction, A = X + Y, the respective concentrations are CA, CX and CY. The forward reaction rate constant is kf and the backward reaction rate constant is kb. Choose the correct statement from the following:
P. At equilibrium, kf CA > kB CxCy
Q. If the reaction is irreversible than, kb CXCY = 0
R. The backward reaction rate will essentially be first order, if the forward reaction rate is first order.
S. Activation energy for the first order forward reaction will be independent of temperature.

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

The fresh feed to an ammonia synthesis reactor contains nitrogen, hydrogen and 2.0 mole per cent inerts. The molar ratio of H2:N2 is 3:1. The product stream consists of pure ammonia. Since conversion in the reactor is only 15%, a recycle stream is used and in order to avoid build-up of inerts, a purge stream is withdrawn. The rate of purge stream is adjusted to keep inert concentration in the recycle stream at 8 mole per cent. For a fresh feed rate of 100 moles/hr. Note that recycle stream contains only nitrogen, hydrogen and inerts. The N2:H2 ratio of 1:3 is maintained in every process stream, and calculate the number of moles, moles of inerts and moles of hydrogen in the recycle stream?