Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Winter 6th Sem New 2160506 Chemical Reaction Engineering I Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? VI (New) EXAMINATION ? WINTER 2019
Subject Code: 2160506 Date: 13/12/2019
Subject Name: Chemical Reaction Engineering - I
Time: 02:30 PM TO 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
MARKS
Q.1 (a) Discuss variables affecting the rate of reaction. 03
(b) A rocket engine burns a stoichiometric mixture of fuel (liquid
hydrogen) in oxidant (liquid oxygen). The combustion chamber
is cylindrical, 75 cm long and 60 cm in diameter, and the
combustion process produces 108 kg/s of exhaust gases. If
combustion is complete, find the rate of reaction of hydrogen
and of oxygen. H2 + ? O2 H2O
04
(c) For a uni-molecular irreversible first order reaction in series
A ? R ? S; Derive an expression for concentration of reactant
A, intermediate product R and final product S as a function of
time. Find the expression in terms of time when formation of R
becomes maximum.
07
Q.2 (a) Differentiate molecularity and order of reaction. 03
(b) Give examples for catalytic homogeneous and heterogeneous
reaction.
04
(c) A homogeneous gas reaction A 3R has a reported rate at
215
O
C
-rA = 10
-2
CA
1/2
, [mol/liter sec]
Find the space-time needed for 80% conversion of a 50% A, 50%
inert feed to a plug flow reactor operating at 215
O
C and 5 atm
(C Ao = 0.0625 mol/liter).
07
OR
(c) What is an autocatalytic reaction? For an autocatalytic reaction
A + R ? R + R show that
ln ?
(?? + ???? )
?? (1 ? ???? )
? = ???? 0 (?? + 1)????
07
Q.3 (a) Consider a feed C Ao = 100, CBO = 200, Cio = 100 to a steady-flow
reactor. The isothermal gas-phase reaction is
A + 3B 6R
If CA = 40 at the reactor exit, what is CB, XA, and XB there?
03
(b) Write in brief about Shifting order reaction. 04
(c) Reactant A decomposes in a batch reactor. A Product
The composition of A in the reactor is measured at various times.
Find a rate equation to represent the data using integral method
of analysis.
Time, t sec 0 20 40 60 120 180 300
Conc. C A
mol/ litre
11 9 7.2 6.5 4.3 3 2
07
OR
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? VI (New) EXAMINATION ? WINTER 2019
Subject Code: 2160506 Date: 13/12/2019
Subject Name: Chemical Reaction Engineering - I
Time: 02:30 PM TO 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
MARKS
Q.1 (a) Discuss variables affecting the rate of reaction. 03
(b) A rocket engine burns a stoichiometric mixture of fuel (liquid
hydrogen) in oxidant (liquid oxygen). The combustion chamber
is cylindrical, 75 cm long and 60 cm in diameter, and the
combustion process produces 108 kg/s of exhaust gases. If
combustion is complete, find the rate of reaction of hydrogen
and of oxygen. H2 + ? O2 H2O
04
(c) For a uni-molecular irreversible first order reaction in series
A ? R ? S; Derive an expression for concentration of reactant
A, intermediate product R and final product S as a function of
time. Find the expression in terms of time when formation of R
becomes maximum.
07
Q.2 (a) Differentiate molecularity and order of reaction. 03
(b) Give examples for catalytic homogeneous and heterogeneous
reaction.
04
(c) A homogeneous gas reaction A 3R has a reported rate at
215
O
C
-rA = 10
-2
CA
1/2
, [mol/liter sec]
Find the space-time needed for 80% conversion of a 50% A, 50%
inert feed to a plug flow reactor operating at 215
O
C and 5 atm
(C Ao = 0.0625 mol/liter).
07
OR
(c) What is an autocatalytic reaction? For an autocatalytic reaction
A + R ? R + R show that
ln ?
(?? + ???? )
?? (1 ? ???? )
? = ???? 0 (?? + 1)????
07
Q.3 (a) Consider a feed C Ao = 100, CBO = 200, Cio = 100 to a steady-flow
reactor. The isothermal gas-phase reaction is
A + 3B 6R
If CA = 40 at the reactor exit, what is CB, XA, and XB there?
03
(b) Write in brief about Shifting order reaction. 04
(c) Reactant A decomposes in a batch reactor. A Product
The composition of A in the reactor is measured at various times.
Find a rate equation to represent the data using integral method
of analysis.
Time, t sec 0 20 40 60 120 180 300
Conc. C A
mol/ litre
11 9 7.2 6.5 4.3 3 2
07
OR
2
Q.3 (a) Give examples for series, parallel and autocatalytic reactions. 03
(b) Explain Space time and space velocity in detail. 04
(c) Derive general equation showing the time required to achieve a
conversion XA for either isothermal or non-isothermal operation
for ideal batch reactor with graphical representation.
07
Q.4 (a) Define fractional yield and selectivity in detail. 03
(b) Explain Plug Flow Reactors in Series and in Parallel with
equation.
04
(c) Discuss in detailed about product distribution for parallel
reaction.
07
OR
Q.4 (a) Liquid A decomposes by first-order kinetics, and in a batch
reactor 50% of A is converted in a 5-minute run. How much
longer would it take to reach 75% conversion?
03
(b) Discuss method of maximization of rectangles applied to find the
optimum intermediate conversion and optimum sizes of two
mixed flow reactors in series.
04
(c) Give detail classification of reactions. 07
Q.5 (a) Give criteria for best Arrangement of a Set of Ideal Reactors. 03
(b) Give comparison for mixed Vs. plug flow reactor. 04
(c) Derive equation for complete conversion for adiabatic operation. 07
OR
Q.5 (a) Write in brief about thermodynamic equilibrium constant. 03
(b) Write physical significance of activation energy. Also discuss
temperature dependency of activation energy using Arrhenius
theory.
04
(c) Derive performance equation for Recycle reactor. 07
*************
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This post was last modified on 20 February 2020