Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Winter 7th Sem New 2173514 Environmental Reaction Engineering Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? VII (New) EXAMINATION ? WINTER 2019
Subject Code: 2173514 Date: 28/11/2019
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) Differentiate order and molecularity of a reaction 03
(b) On doubling the concentration of reactant, rate of reaction triples. Find the
reaction order.
04
(c) Explain how different theories predict temperature dependency of reaction
rate
07
Q.2 (a) Discuss Integral method for analysis of rate data. 03
(b) Derive the integrated form of rate expression for Irreversible unimolecular
type Second order reactions.
04
(c) The half life period for a certain first order reaction is 2.5 ? 10
3
sec. How long
will it take for 1/4
th
of reactant to be left behind.
07
OR
(c) A polymerization reaction occurs at constant temperature in a homogeneous
phase. For initial monomer concentrations of 0.3, 0.5 and 0.9 mol/l, 30% of
monomer reacts in 40 minutes. Find the reaction rate.
07
Q.3 (a) How overall order of a reaction can be estimated from half-life method? 03
(b) What is variable volume reactor 04
(c) Prove that for a first order reaction N-CSTRs connected in series will
approximate to the behavior of PFR.
07
OR
Q.3 (a) Specify how holding time and space time varies for flow reactors. 03
(b) In an isothermal batch reactor 70% of reactant A is converted in 13 minutes.
Find the space time and space velocity to effect this conversion in a plug flow
reactor assuming first order kinetics.
04
(c) Discuss the case of qualitative product distribution and concentration levels
to be maintained in case of parallel competing unimolecular reactions of
desired and undesired reactions considering their order.
07
Q.4 (a) Specify the differences between ideal and non-ideal reactors 03
(b) How E curve can be determined though pulse input experiments? 04
(c) Calculate the mean residence time for a reactor from following data
t, min 0 1 2 3 4 5 6 7 8
E, min
-1
0 0.02 0.10 0.16 0.20 0.12 0.08 0.03 0
07
OR
Q.4 (a) What should be essential properties a catalyst? 03
(b) Write the steps involved in a Catalytic reaction. 04
(c) Synthesize a rate law for the decomposition of Cumene to form benzene and
propylene considering that surface reaction is rate limiting step.
07
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? VII (New) EXAMINATION ? WINTER 2019
Subject Code: 2173514 Date: 28/11/2019
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) Differentiate order and molecularity of a reaction 03
(b) On doubling the concentration of reactant, rate of reaction triples. Find the
reaction order.
04
(c) Explain how different theories predict temperature dependency of reaction
rate
07
Q.2 (a) Discuss Integral method for analysis of rate data. 03
(b) Derive the integrated form of rate expression for Irreversible unimolecular
type Second order reactions.
04
(c) The half life period for a certain first order reaction is 2.5 ? 10
3
sec. How long
will it take for 1/4
th
of reactant to be left behind.
07
OR
(c) A polymerization reaction occurs at constant temperature in a homogeneous
phase. For initial monomer concentrations of 0.3, 0.5 and 0.9 mol/l, 30% of
monomer reacts in 40 minutes. Find the reaction rate.
07
Q.3 (a) How overall order of a reaction can be estimated from half-life method? 03
(b) What is variable volume reactor 04
(c) Prove that for a first order reaction N-CSTRs connected in series will
approximate to the behavior of PFR.
07
OR
Q.3 (a) Specify how holding time and space time varies for flow reactors. 03
(b) In an isothermal batch reactor 70% of reactant A is converted in 13 minutes.
Find the space time and space velocity to effect this conversion in a plug flow
reactor assuming first order kinetics.
04
(c) Discuss the case of qualitative product distribution and concentration levels
to be maintained in case of parallel competing unimolecular reactions of
desired and undesired reactions considering their order.
07
Q.4 (a) Specify the differences between ideal and non-ideal reactors 03
(b) How E curve can be determined though pulse input experiments? 04
(c) Calculate the mean residence time for a reactor from following data
t, min 0 1 2 3 4 5 6 7 8
E, min
-1
0 0.02 0.10 0.16 0.20 0.12 0.08 0.03 0
07
OR
Q.4 (a) What should be essential properties a catalyst? 03
(b) Write the steps involved in a Catalytic reaction. 04
(c) Synthesize a rate law for the decomposition of Cumene to form benzene and
propylene considering that surface reaction is rate limiting step.
07
2
Q.5 (a) Mention Fick?s first law of diffusion. Specify the contributions of a liquid
mixture to its total flux
03
(b) What is meant by Mass transfer boundary layer thickness? 04
(c) Calculate the mass flux of reactant A to a single catalyst pellet of 1 cm in
diameter suspended in a liquid. The reactant is placed in dilute concentrations
and reaction is considered to take place instantaneously at external pellet
surface. The bulk concentration of reactant is 1 M and free system liquid
velocity is 0.1 m/s. The kinematic viscosity is 0.5 cS and the liquid diffusivity
is 10
-10
m
2
/s.
OR
Q.5 (a) What is Thiele Modulus? Specify the importance of this factor in a catalytic
reaction.
03
(b) Discuss the correlation between Effective diffusivity and tortousity 04
(c) Correlate the time needed for complete conversion of a spherical particle
considering that chemical reaction is rate governing step in shrinking core
model.
07
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This post was last modified on 20 February 2020