The following are the data recorded by the DO probe: Airflow (LPM) Agitation Speed (RPM) Run 1 Run 2 Run 3 Run 4 1.0 1.0 1.0 3.0 100 400 700 400 Time DO Time DO Time DO Time DO (min) (%) (min) (%) (min) (%) (min) (%) 0 0 2.5 18 .5 30 10 66 15 85 20 90 012345 0 0 0 0 0 30 0.5 22 0.5 20 75 57 1 50 80 1.5 80 2 72 90 2 88 3 86 95 2.5 92 4 92 Please obtain the following: 1. Integrate Equation 1 to provide the relationship between c, vs. t. 2. Using the results from question 1, determine kα for Runs 1, 2, 3, and 4. 3. Explain which parameter has a greater effect on the oxygen transfer rate: the air flow rate or the agitation speed.

Introduction to Chemical Engineering Thermodynamics
8th Edition
ISBN:9781259696527
Author:J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart
Publisher:J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart
Chapter1: Introduction
Section: Chapter Questions
Problem 1.1P
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Same problem but in 2 parts. Put these 2 pictures together is the whole.

The following are the data recorded by the DO probe:
Airflow
(LPM)
Agitation Speed
(RPM)
Run 1
1.0
Time
(min)
0
2.5
5
100
10
15
20
DO
(%)
0
18
30
66
85
90
Run 2
1.0
400
Time
DO
(min) (%)
0
0
1
30
2
75
3
80
90
95
45
Run 3
1.0
Time
(min)
0
0.5
1
1.5
:/N/
700
2.5
DO
(%)
0
22
57
80
88
92
in88
Run
3.0
Time
(min)
0
0.5
2
400
3
4
DO
(%)
0
20
50
72
86
92
Please obtain the following:
1. Integrate Equation 1 to provide the relationship between c, vs. t.
2. Using the results from question 1, determine ka for Runs 1, 2, 3,
and 4.
1
3. Explain which parameter has a greater effect on the oxygen transfer
rate: the air flow rate or the agitation speed.
Transcribed Image Text:The following are the data recorded by the DO probe: Airflow (LPM) Agitation Speed (RPM) Run 1 1.0 Time (min) 0 2.5 5 100 10 15 20 DO (%) 0 18 30 66 85 90 Run 2 1.0 400 Time DO (min) (%) 0 0 1 30 2 75 3 80 90 95 45 Run 3 1.0 Time (min) 0 0.5 1 1.5 :/N/ 700 2.5 DO (%) 0 22 57 80 88 92 in88 Run 3.0 Time (min) 0 0.5 2 400 3 4 DO (%) 0 20 50 72 86 92 Please obtain the following: 1. Integrate Equation 1 to provide the relationship between c, vs. t. 2. Using the results from question 1, determine ka for Runs 1, 2, 3, and 4. 1 3. Explain which parameter has a greater effect on the oxygen transfer rate: the air flow rate or the agitation speed.
Oxygen supply to a cell is vital for proper growth, especially in a controlled
environment such as a fermentor or bioreactor. When companies are building new
fermenters, a very important design consideration concerns the oxygen supply. It is
thus important for engineers to determine the k,a in the fermentor to determine if
the system can meet the oxygen demands of the cell.
The dissolved oxygen (DO) reading from a dissolved oxygen probe is
expressed in terms of a percentage of the saturated DO concentration, c*. In the lab,
the saturated DO concentration was measured to be c*=8.65 at 25°C and 1 atm.
A DO probe reading of 100% indicates that the DO oxygen concentration is thus
8.65. In the fermentor, oxygen gas is supplied to the cells via the air sparger and
agitation. When the DO reading is less than 15-20%, the cells begin to die.
During the oxygen transfer from gas to liquid, the concentration of dissolved
oxygen in the fermentor medium, c₁, can be expressed as:
dc₁_k₂a(c* -c₁)
(1)
=
dt
where ka is the mass transfer coefficient. At the beginning of the experiment, the
oxygen in the fluid medium is depleted and thus: c₁=0 att = 0.
The following is a procedure to determine the k,a in a lab:
1. Fill the fermentor with 2 L of water.
2. Sparge the fermentor with nitrogen for 10 minutes. Verify that the DO is
less than 2%..
3. Turn on the air flow and agitation to the specified rate. Record the DO
reading versus time.
4. Covert DO reading to c₁. (When DO = 100%, C₁=c* = 8.65). Plot c₁ vs.
time.
5. Calculate ka.
Transcribed Image Text:Oxygen supply to a cell is vital for proper growth, especially in a controlled environment such as a fermentor or bioreactor. When companies are building new fermenters, a very important design consideration concerns the oxygen supply. It is thus important for engineers to determine the k,a in the fermentor to determine if the system can meet the oxygen demands of the cell. The dissolved oxygen (DO) reading from a dissolved oxygen probe is expressed in terms of a percentage of the saturated DO concentration, c*. In the lab, the saturated DO concentration was measured to be c*=8.65 at 25°C and 1 atm. A DO probe reading of 100% indicates that the DO oxygen concentration is thus 8.65. In the fermentor, oxygen gas is supplied to the cells via the air sparger and agitation. When the DO reading is less than 15-20%, the cells begin to die. During the oxygen transfer from gas to liquid, the concentration of dissolved oxygen in the fermentor medium, c₁, can be expressed as: dc₁_k₂a(c* -c₁) (1) = dt where ka is the mass transfer coefficient. At the beginning of the experiment, the oxygen in the fluid medium is depleted and thus: c₁=0 att = 0. The following is a procedure to determine the k,a in a lab: 1. Fill the fermentor with 2 L of water. 2. Sparge the fermentor with nitrogen for 10 minutes. Verify that the DO is less than 2%.. 3. Turn on the air flow and agitation to the specified rate. Record the DO reading versus time. 4. Covert DO reading to c₁. (When DO = 100%, C₁=c* = 8.65). Plot c₁ vs. time. 5. Calculate ka.
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