課程名稱︰質能平衡甲
課程性質︰系定必修
課程教師︰蔡偉博
開課學院：工學院
開課系所︰化學工程系
考試日期（年月日）︰2008年5月13日
考試時限（分鐘）：1330~1510（100分鐘）
是否需發放獎勵金：是，謝謝
（如未明確表示，則不予發放）
試題 :
1.Brief questions (10 points)
(A) Gibbs phase rule
(B) Absolute saturation
(C) Henry’s law
(D) Critical temperature
2.(20 points) 1000 kg of a 30.0% solution of acetone in water and a second
stream of pure methyl isobutyl ketone (MIBK) is fed to a mixer. The mixture is
then fed to a settler where two phases form and are withdrawn separately at
25oC. If the acetone concentration in water-rich phase is half of the acetone
concentration in MIBK-rich phase, how much MIBK must be fed to the process,
assuming that the fluids remain in the settler long enough for equilibrium to
be achieved? what percentage of the acetone is transferred from the water to
the MIBK?
3.(20 points) A local utility burns coal having the following composition
on a dry basis.
Component Percent
C 83.05
H 4.45
O 3.36
N 1.08
S 0.70
Ash 7.36
Total 100.0
The average Orsat analysis of the gas from the stack during a 24-hour test was
Component Percent
CO2+SO2 15.4
CO 0.0
O2 4.0
N2 80.6
Total 100.0
Moisture in the fuel was 3.90%, and the air on the average contained
0.0048 lb H2O/lb dry air. The refuse showed 14.0% unburned coal, with the
remainder being ash.
You are asked to check the consistency of the data before they are stored in a
database. Is the consistency satisfactory? What was the average percentage
excess air used?
4. (20 points) Dry ice (solid CO2) has been used as a mine explosive
in the following manner. A hole is drilled into the mine wall, filled with dry
ice plus a small charge of gun powder, and then plugged. The gun powder is
lit with a fuse, vaporizing the CO2 and building up an explosively high
pressure within the hole. Use the compressibility-factor equation of state to
estimate the pressure that will develop if 5.00 g of dry ice is placed in a
50.0-mL hole and heated to 1000 K.
(For CO2: Tc=304.2 K, Pc=72.9 atm)
5. (20 points) To condition the air in an office building in the
winter, 1000 m3 of moist air per hour at 101 kPa and 22oC with a dew point of
11oC enter the system. The air leaves the system at 98 kPa with a dew point of
58oC. How many kilograms of water vapor are added to each kilogram of wet air
entering the process?
P*H20(11oC) = 9.84 mmHg, P*H20(58 oC) = 136.1 mmHg
6. (20 points) Ethylene oxide is produced by the catalytic oxidation
of ethylene:
2 C2H4 + O2 -----> 2 C2H4O
An undesired competing reaction is the combustion of ethylene:
C2H4 + 3 O2 -----> 2 CO2 + 2 H2O
The feed to the reactor contain 3 moles of ethylene per mole of oxygen. The
single-pass conversion of ethylene is 20%, and for every 100 moles of ethylene
consumed in the reactor, 90 moles of ethylene oxide emerges in the reactor
products. A multiple-unit process is used to separate the products: ethylene
and oxygen are recycled to the reactor, ethylene oxide is sold as a product,
and carbon dioxide and water are discarded.
Calculate (i) the molar flow rates of ethylene and oxygen in the fresh feed
needed to produce 1 ton per hour of ethylene oxide; (ii) the production rate of
ethylene oxide; (iii) the overall conversion of ethylene.
[Attached figure:
"Elementary Principles of Chemical Processes" 3rd edition,by Richard M.Felder
Ronald W.Rousseau
FIGURE 6.6-1 (p.274)
FIGURE 5.4-4 (p.211)]
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