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(CENG211)[2010](f)midterm_answer_only~=yd5l1^_50358.pdf
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Question 1
a)
Mole balance (Sodium Hydroxide)
dVrFFdtdNVAAAoA....
Well mixed, batch reaction:
VrdtdNAA.
Mole balance (Hydrogen Chloride)
dVrFFdtdNVBBBoB....
Well mixed, batch reaction:
VrdtdNBB.
y = -0.0146x + 3.1394R2 = 0.5869
-1
0
1
2
3
4
5
6
0
50
100
150
200
250
300
CA(M)
t(min)
y = -0.0098x + 1.1384R2 = 0.8786
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
0
50
100
150
200
250
300
ln(CA)
t(min)
y = 0.0099x + 0.2057R2 = 0.9999
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0
50
100
150
200
250
300
1/CA (M-1)
t(min)
Therefore, the differential equation system for the batch reactor:
Given parameter:
V=2L
Initial condition:
NA=1M x 1L=1mol
NB=1M x 1L=1mol
b)
Assume that the 1M NaOH solution was added steadily into the 1M HCl solution
Volumetric flowrate of 1M NaOH solution adding into the beaker
min1033.8min12530001.04LxdropsdropsLv.....
The molar feed rate of 1M NaOH solution:
min1033.8min6005.014molLLmolvCFAoAo........
Mole balance (Sodium Hydroxide):
dVrFFdtdNVAAAoA....
Well-mixed, semi-batch system:
VrFdtdNAAoA..
Mole balance (Hydrogen Chloride):
dVrFFdtdNVBBBoB....
Well-mixed, semi-batch system:
VrdtdNBB.
The change rate of the reaction fluid volume:
vdtdV..
Therefore, the differential equation system for the semi-batch reactor:
VrdtdNBB.
Where:
min1033.84molFAo...
min1033.84Lv....
Initial condition:
NA=0mol
NB=1M x 1L=1mol
V=1L
c)
Two advantages:
Batch reactor:
i) Reaction rate is faster
ii) Easier for obtaining reaction kinetics
Semi-batch reactor:
i) Heat dissipation is better
ii) Complete reaction
Other reasonable answers are also accepted.
Question 2
Assumption:
The beef is solid and cooking is mainly by thermal denaturing of protein.
Given:
A . B
Activation energy = 5kJ.mol-1 (Version 1) or 15kJ.mol-1(Version 2)
Find:
Mole balance equation:
Consider the pressure cooker as a batch reactor:
The temperature required to halve the cooking time at 100oC
Arrhenius equation:
T1=100oC=373K, For T=T2, k=k2=2k1
For Ea=5000J/mol
For Ea=15000J/mol
Discuss how this is achieve in the pressure cooker
When pressure increase, the boiling point of water/solvent increase and hence the water can be heated up to a higher temperature without evaporated to cook the beef.
Problem 1
(CSTR or PFR system)
C + D
A + B
The feed is stoichiometric mix