Aspects of Biochemical Engineering - - Unit 5 -... https://onlinecourses.nptel.ac.in/noc18_bt02/uni...

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Unit 5 - Week 4

Course
outline
Week 4 Assignment 1
The due date for submitting this assignment has passed. Due on 2018-02-21, 23:59 IST.
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the portal Submitted assignment

Week 1 1) The following process is suitable for secondary metabolites production 1 point

Week 2 Batch

Fed-batch
Week 3
Continuous flow stirred tank reactor
Week 4 None of these

Lecture 16: No, the answer is incorrect.

Different types Score: 0
of reactors
Accepted Answers:
Lecture 17: Fed-batch
Reactor
analysis 2) In a continuous flow stirred tank reactor the composition of exit stream under steady state 1 point
Lecture 18: condition
Reactor
analysis II Is same as that in the reactor

Lecture 19: Is different than that in the reactor

Reactor
analysis III Depends upon the reactor volume

Lecture 20: None of these

Reactor
No, the answer is incorrect.
analysis IV
Score: 0
Week 4 Lecture
Accepted Answers:
Material
Is same as that in the reactor
Quiz : Week 4
Assignment 1 3) In the fluidized bed, the velocity of the fluid varies in the range 1 point

Week 4
6-20 m/h
Assignment 1
Solution 3-6 m/h

Week 5 1-3 m/h

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Aspects of Biochemical Engineering - - Unit 5 -... https://onlinecourses.nptel.ac.in/noc18_bt02/uni...

4) Most suitable reactor by

Powered for algae cultivation is 1 point
Week 9

Trickle bed reactor

Week 10
Packed bed reactor
Week 11
Airlift reactor

Week 12 None of these

No, the answer is incorrect.

DOWNLOAD
VIDEOS Score: 0
Accepted Answers:
Airlift reactor

5) Space time of 3 h for continuous flow reactor means that 1 point

The time required to process one reactor volume of feed is 3 h

Three reactor volumes of feed can be processed every hour

It takes 3 h to dump the entire volume of the reactor with feed

Substrate conversion is 100% after three hours

No, the answer is incorrect.

Score: 0
Accepted Answers:
The time required to process one reactor volume of feed is 3 h

6) The performance equations for constant density systems are identical for 1 point

PFR and CSTR

PFR and batch reactor

PFR, batch reactor and CSTR

Batch reactor and CSTR

No, the answer is incorrect.

Score: 0
Accepted Answers:
PFR and batch reactor

7) In an ideal tubular flow reactor 1 point

There is no mixing in longitudinal direction

Mixing takes place in radial direction

There is uniform velocity of fluid in axial direction

All of these

No, the answer is incorrect.

Score: 0
Accepted Answers:
All of these

8) The following reaction rate curve is shown for a reaction A→P. Here, (-rA) and XA represent 1 point
reaction rate and fractional conversion, respectively. The feed is pure A and 90% conversion is desired

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Aspects of Biochemical Engineering - - Unit 5 -... https://onlinecourses.nptel.ac.in/noc18_bt02/uni...

Which amongst the following reactor configuration gives the lowest total volume of the reactor (s)?

CSTR followed by PFR

Two CSTRs is series

PFR followed by CSTR

A single PFR

No, the answer is incorrect.

Score: 0
Accepted Answers:
CSTR followed by PFR

9) The degree of conversion when feed (80 g/L) is converted to product (30 g/L) 1 point

50%

62.5%

72.5%

52.5%

No, the answer is incorrect.

Score: 0
Accepted Answers:
62.5%

10)A homogeneous liquid phase reaction A→R −rA = kCA2 takes place with 50% conversion in 1 point
an isothermal CSTR. What will be the conversion if the reactor is replaced by a PFR of equal size all else
remaining the same

50%

42%

67%

90%

No, the answer is incorrect.

Score: 0
Accepted Answers:
67%

11)In an aqueous solution, reaction P→Q occurs under isothermal conditions following first order 1 point
kinetics. The feed rate is 500 mL/min and the concentration of P in the feed is 1.5×10-4 mol/mL. The reaction
is carried out in a 5 L CSTR. At steady state, 60% conversion of P is observed. The rate constant (min-1) of
the reaction is

0.25

0.15

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Aspects of Biochemical Engineering - - Unit 5 -... https://onlinecourses.nptel.ac.in/noc18_bt02/uni...

0.05

0.35

No, the answer is incorrect.

Score: 0
Accepted Answers:
0.15

12)A liquid phase reaction A→B, is conducted isothermally in a CSTR having residence time 2 s. 1 point
The inlet concentration of species A is 2 mol/L, and the outlet concentration is 1 mol/L. The rate equation for
k1 CA
the reaction is(−rA ) = . Where, k1= 5 mol/L.s. The value of k2 in mol/L is
k2 +CA

11

No, the answer is incorrect.

Score: 0
Accepted Answers:
9

13)Time required for 50% decomposition of reactant in liquid phase isothermal batch reactor 1 point
following first order kinetics is 2 min. The time required for 75% decomposition will be about __________
min.

No, the answer is incorrect.

Score: 0
Accepted Answers:
4

14)The plug flow reactor may be replaced by 1 point

CSTR in parallel

CSTR in series

Single CSTR

None of the above

No, the answer is incorrect.

Score: 0
Accepted Answers:
CSTR in series

15)Under steady state condition, the following parameter is zero 1 point

Rate of disappearance of substrate

Rate of output of substrate

Rate of accumulation of substrate

All the above

No, the answer is incorrect.

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Aspects of Biochemical Engineering - - Unit 5 -... https://onlinecourses.nptel.ac.in/noc18_bt02/uni...

Score: 0
Accepted Answers:
Rate of accumulation of substrate

16)A pollutant P degrades according to first order kinetics. An aqueous stream containing P at 2 1 point
kmol/m3 and volumetric flow rate 1 m3 /h requires a mixed flow reactor of volume V to bring down the
pollutant level to 0.5 kmol/m3 . The inlet concentration of the pollutant is now doubled and the volumetric
flow rate is tripled. If the pollutant level is to be brought down to the same level of 0.5 kmol/m3 , the volume
of the mixed flow reactor should be increased by a factor of

7/3

No, the answer is incorrect.

Score: 0
Accepted Answers:
7

17)Decomposition of the reactant follows irreversible first order kinetics and the half-life period of 1 point
this reaction is 8 min. The time requires for 75% conversion of the liquid will be

4 min

8 min

12 min

16 min

No, the answer is incorrect.

Score: 0
Accepted Answers:
16 min

18)The conversion of A for a first order liquid phase reaction A ⟶ B : in a CSTR is 50%. If 1 point
another CSTR of same volume is connected in series, then the overall conversion will be

60 %

75 %

90 %

100 %

No, the answer is incorrect.

Score: 0
Accepted Answers:
75 %

19)The liquid phase reaction, A Products, is governed by the kinetics,(−rA ) = kCA1/2 . If the 1 point
reaction undergoes 75% conversion of A in 10 min in an isothermal batch reactor, the time (in min) requires
for the complete conversion of A is

40/3

20

30

Infinite

No, the answer is incorrect.

Score: 0

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Aspects of Biochemical Engineering - - Unit 5 -... https://onlinecourses.nptel.ac.in/noc18_bt02/uni...

Accepted Answers:
20

20)The liquid phase reaction, A→B+C, is conducted isothermally at 50 ℃ in a continuous flow 1 point
stirred tank reactor (CSTR). The inlet concentration of A is 8.0 g-mol /L. At a space-time of 5 min, the
concentration of A at the exit of CSTR is 4.0 g-mol/L. The kinetics of the reaction is (−rA ) = kCA The rate
constant (k) for this reaction at 50 ℃

0.1 min1

0.4 min1

0.3 min1

0.2 min1

No, the answer is incorrect.

Score: 0
Accepted Answers:
0.2 min1

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