Printed Pages—2 ECH607
(Following Paper ID and Roll No. to be filled in your Answer Book)
PAPER ID : 2468 Roll No.
B.Tech.
(SEM. VI) EVEN THEORY EXAMINATION 2012-13
CHEMICAL REACTION ENGINEERING
Time : 2 Hours Total Marks : 50
Note :– Attempt all questions. Assume suitable data, if required.
1. Attempt any four parts of the following : (3×4=12)
(a) Discuss Electrochemical Reactors with suitable examples.
(b) Describe Arrhenius theory. What is activation energy for
chemical reaction ?
(c) Discuss the Yield and Selectivity of a reaction with suitable
examples.
(d) What is space time and holding time ? Give the suitable
examples also.
(e) Write a short note on the non-isothermal behaviour of a
reaction with suitable examples.
(f) Differentiate between “Elementary and non-elementary
reactions” with suitable examples.
2. Attempt any two parts of the following : (7×2=14)
(a) An aqueous reactant stream (12 mol A/litre) passes through
a CSTR followed by a PFR. Find the concentration at the
exit of the PFR, if in the CSTR CA = 2.5 mol/litre. The
reaction is second order with respect to A, and the volume
of the PFR is 4 times that of CSTR.
ECH607/DPC-47907 [Turn Over
(b) Find the first order rate constant for disappearance of A in
the gas reaction 2A → B, if on holding the pressure constant,
the volume of the reaction mixture, starting with 72% A,
decrease by 18% in 4 minutes.
(c) What do you understand by variable volume batch
reactor ? Differentiate it with constant Volume Batch
Reactor. Derive an expression of fractional conversion of
reactant (XA) for a variable volume batch reactor.
(d) For a series reaction A →1
KR→2K S, derive an
expression CR and also prove that time taken to obtain the
maximum concentration of R(CRmax) equals the log mean
kinetic constant difference.
3. Attempt any two parts of the following : (6×2=12)
(a) Derive the performance equation for a CSTR with
complete assumptions.
(b) Discuss the Differential method of analysing the kinetic
data with a suitable example.
(c) Three CSTRs and one PFR of different sizes are connected
in series. Discuss the behaviour of the system and also
explain the scheme for connecting the reactors with neat
diagram.
4. Write short notes on any four of the following : (3×4=12)
(a) Size comparison of single reactors.
(b) Molecularity and Order of reaction.
(c) Variables affecting the reaction rate.
(d) Collision theory
(e) Semi-batch reactor.
(f) Autocatalytic reactions.
ECH607/DPC-47907 50
