Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2018 Winter 7th Sem New 21735142173509 Environmental Reaction Engineering Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?VII (NEW) EXAMINATION ? WINTER 2018
Subject Code: 2173514/2173509 Date: 26/11/2018
Subject Name: Environmental Reaction Engineering
Time: 10:30 AM TO 01:00 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) Define: 1) space time, 2) space velocity, 3) Recycle ratio 03
(b) Discuss size comparison of mixed flow reactor and plug flow
reactor for n
th
order reaction.
04
(c) Derive the process design equation for mixed flow reactor. 07
Q.2 (a) Discuss advantages and disadvantages of batch reactor. 03
(b) Justify that CSTRs connected in parallel behave as one single
CSTR of the same total volume.
04
(c) In an isothermal batch reactor, the conversion of a liquid
reactant A is 70% in 13 minutes. Find the space time and space
velocity necessary to effect this conversion in a plug flow
reactor. Consider first order kinetics.
07
OR
(c) A homogeneous liquid phase reaction with the stoichiometry
and the kinetics A S, -rA = KCA
2
takes place with 50%
conversion in a MFR.
1) Find the conversion if this reactor is replaced by another
MFR having volume 6 times that of the original reactor
or other parameters remain same.
2) Find the conversion if the original reactor is replaced by
plug flow reactor of the same size. All other parameters
remain same.
07
Q.3 (a) Explain instantaneous fractional yield and overall fractional
yield.
03
(b) For following parallel reactions
A R
A S
If R is the desired product and the order of reaction is same for
both the reactions then how can one get more production of R?
04
(c) Prove that N number of same sized mixed flow reactors in series
can be approximated as a plug flow reactor.
07
OR
Q.3 (a) The reactor setup consists of three plug flow reactors in two
parallel branches. Branch D has a reactor of volume 60 liters
followed by a reactor of volume 40 liters. Branch E has a
reactor of volume 50 liters. What fraction of the feed should go
to branch D?
03
(b) For reactions in series
A R S
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?VII (NEW) EXAMINATION ? WINTER 2018
Subject Code: 2173514/2173509 Date: 26/11/2018
Subject Name: Environmental Reaction Engineering
Time: 10:30 AM TO 01:00 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) Define: 1) space time, 2) space velocity, 3) Recycle ratio 03
(b) Discuss size comparison of mixed flow reactor and plug flow
reactor for n
th
order reaction.
04
(c) Derive the process design equation for mixed flow reactor. 07
Q.2 (a) Discuss advantages and disadvantages of batch reactor. 03
(b) Justify that CSTRs connected in parallel behave as one single
CSTR of the same total volume.
04
(c) In an isothermal batch reactor, the conversion of a liquid
reactant A is 70% in 13 minutes. Find the space time and space
velocity necessary to effect this conversion in a plug flow
reactor. Consider first order kinetics.
07
OR
(c) A homogeneous liquid phase reaction with the stoichiometry
and the kinetics A S, -rA = KCA
2
takes place with 50%
conversion in a MFR.
1) Find the conversion if this reactor is replaced by another
MFR having volume 6 times that of the original reactor
or other parameters remain same.
2) Find the conversion if the original reactor is replaced by
plug flow reactor of the same size. All other parameters
remain same.
07
Q.3 (a) Explain instantaneous fractional yield and overall fractional
yield.
03
(b) For following parallel reactions
A R
A S
If R is the desired product and the order of reaction is same for
both the reactions then how can one get more production of R?
04
(c) Prove that N number of same sized mixed flow reactors in series
can be approximated as a plug flow reactor.
07
OR
Q.3 (a) The reactor setup consists of three plug flow reactors in two
parallel branches. Branch D has a reactor of volume 60 liters
followed by a reactor of volume 40 liters. Branch E has a
reactor of volume 50 liters. What fraction of the feed should go
to branch D?
03
(b) For reactions in series
A R S
2
If the desired product is S then explain which method should
be used?
(c) Reactant A in liquid produces R and S by the following
reaction:
R
A
S
Both these reactions are first order.
A feed with C A0 = 1, CR0 = 0 and CS0 = 0 enters in two mixed
flow reactors in series ( ?1 = 2 min, ?2 = 5 min). The composition
in the first reactor is C A1 = 0.40, CR1 = 0.40 and CS1 = 0.2. Find
the composition leaving the second reactor.
07
Q.4 (a) Define mean residence time and variance with equation. 03
(b) Explain pulse input experiment for RTD studies. 04
(c) The data given below represent a continuous response to a
pulse input into a closed vessel which is to be used as a
chemical reactor. Calculate the mean residence time of fluid in
the vessel and tabulate and construct the E curve.
t, min Cpulse , g/l
0 0
5 3
10 5
15 5
20 4
25 2
30 1
35 0
07
OR
Q.4 (a) What are the causes of non-ideal flow in reactor? 03
(b) Explain relationship between E and F curve. 04
(c) A sample of tracer hytane was injected as a pulse into a vessel
(to be used as a reactor) and the effluent concentration is
measured as a function of time. The following data are
obtained:
t,min C (g/m
3
)
0 0
1 1
2 5
3 8
4 10
5 8
6 6
7 4
8 3
9 2.2
10 1.5
12 0.6
14 0
Construct the C and E curves and determine the fraction of
material leaving the vessel that has spent between 3 and 6 min
in the vessel.
07
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?VII (NEW) EXAMINATION ? WINTER 2018
Subject Code: 2173514/2173509 Date: 26/11/2018
Subject Name: Environmental Reaction Engineering
Time: 10:30 AM TO 01:00 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) Define: 1) space time, 2) space velocity, 3) Recycle ratio 03
(b) Discuss size comparison of mixed flow reactor and plug flow
reactor for n
th
order reaction.
04
(c) Derive the process design equation for mixed flow reactor. 07
Q.2 (a) Discuss advantages and disadvantages of batch reactor. 03
(b) Justify that CSTRs connected in parallel behave as one single
CSTR of the same total volume.
04
(c) In an isothermal batch reactor, the conversion of a liquid
reactant A is 70% in 13 minutes. Find the space time and space
velocity necessary to effect this conversion in a plug flow
reactor. Consider first order kinetics.
07
OR
(c) A homogeneous liquid phase reaction with the stoichiometry
and the kinetics A S, -rA = KCA
2
takes place with 50%
conversion in a MFR.
1) Find the conversion if this reactor is replaced by another
MFR having volume 6 times that of the original reactor
or other parameters remain same.
2) Find the conversion if the original reactor is replaced by
plug flow reactor of the same size. All other parameters
remain same.
07
Q.3 (a) Explain instantaneous fractional yield and overall fractional
yield.
03
(b) For following parallel reactions
A R
A S
If R is the desired product and the order of reaction is same for
both the reactions then how can one get more production of R?
04
(c) Prove that N number of same sized mixed flow reactors in series
can be approximated as a plug flow reactor.
07
OR
Q.3 (a) The reactor setup consists of three plug flow reactors in two
parallel branches. Branch D has a reactor of volume 60 liters
followed by a reactor of volume 40 liters. Branch E has a
reactor of volume 50 liters. What fraction of the feed should go
to branch D?
03
(b) For reactions in series
A R S
2
If the desired product is S then explain which method should
be used?
(c) Reactant A in liquid produces R and S by the following
reaction:
R
A
S
Both these reactions are first order.
A feed with C A0 = 1, CR0 = 0 and CS0 = 0 enters in two mixed
flow reactors in series ( ?1 = 2 min, ?2 = 5 min). The composition
in the first reactor is C A1 = 0.40, CR1 = 0.40 and CS1 = 0.2. Find
the composition leaving the second reactor.
07
Q.4 (a) Define mean residence time and variance with equation. 03
(b) Explain pulse input experiment for RTD studies. 04
(c) The data given below represent a continuous response to a
pulse input into a closed vessel which is to be used as a
chemical reactor. Calculate the mean residence time of fluid in
the vessel and tabulate and construct the E curve.
t, min Cpulse , g/l
0 0
5 3
10 5
15 5
20 4
25 2
30 1
35 0
07
OR
Q.4 (a) What are the causes of non-ideal flow in reactor? 03
(b) Explain relationship between E and F curve. 04
(c) A sample of tracer hytane was injected as a pulse into a vessel
(to be used as a reactor) and the effluent concentration is
measured as a function of time. The following data are
obtained:
t,min C (g/m
3
)
0 0
1 1
2 5
3 8
4 10
5 8
6 6
7 4
8 3
9 2.2
10 1.5
12 0.6
14 0
Construct the C and E curves and determine the fraction of
material leaving the vessel that has spent between 3 and 6 min
in the vessel.
07
3
Q.5 (a) Define: i) heterogeneous reaction, ii) catalyst, iii) Catalyst
activity
03
(b) Differentiate between packed bed reactor and fluidized bed
reactor.
04
(c) Write the sequence of steps according to shrinking core model for
gas-solid non-catalytic reactions. Draw a schematic figure to show
these steps when reaction A (g) + bB (s) ? products takes place
on a solid spherical particle of unchanging size.
07
OR
Q.5 (a) Differentiate constant volume and variable volume batch
reactor.
03
(b) Explain types of catalyst deactivation. 04
(c) Qualitative discussion about product distribution in reactions in
parallel for two reactant.
07
*************
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This post was last modified on 20 February 2020