[試題] 98下 劉懷勝 單元操作三 期末考
課程名稱︰單元操作三
課程性質︰必修
課程教師︰劉懷勝
開課學院：工學院
開課系所︰化工系
考試日期（年月日）︰2010.6.24
考試時限（分鐘）：100分鐘
是否需發放獎勵金：是
（如未明確表示，則不予發放）
試題 :
close book
1.Explain following terms briefly (20%)
1) Reverse phase chromatography and ion-exchang chromatography
2) Molecular weight cut off and rejection coefficient
3) The difference between primary nucleation and secondary nucleation (e.g
from the view point of solubility, rate, size distribution, controllability)
4) enantiotropic and monotropic in crystallization
5) Process intensification
2.Please draw an electrodialysis and explain how it works. Be sure to specify/
identify the functions of "cation exchange membrane" and "anion exchange memb-
rane" and anion exchanege membrane". (10%)
3. A sample "plug" of a solute, following the adsorption isotherm shown in
Fig. (A) below, is migrating along a fixed bed shown in Fig. (B). Is this
adsorption isotherm a favorable one or unfavorable one and why? (4%) Please
predict/explain how the concentration profile of the solute might be distorted
when it moves along the column when the concentration of the sample is very
low as well as very high. (16%)
(A) Adsorption isotherm
^
Soluion | ╴
concentration ╱
| ∕
| ∕
| /
|︳
|---------------->
Adosorption concentration
(B) A "plug" of solute migrating along the fixed bed
^ ^
| ∕ ﹨ ---------> ??
| ∕ ﹨
|--------------------------->
-----------------------------
washing---|-> | █ |
fluid | | █ |
|----------------------------
4. What are the possible mechanisms of membrane fouling? And what are the ways
to eliminate or reduce fouling? (10%)
open book
1. Data for the filtration of CaCO3 slurry in water at 25°C are reproted as
follows at a constant pressure 6.7 psia. The area of the plate-and-frame press
was 0.439 m^2 and the slurry concentration was 23.47 kg solid/m^3 filtrate.
Calculate the constant of specific resistance and membrane resistance. (20%)
Time(min) Filtrate volume (m^3)
17.3 0.5
41.3 1.0
72.0 1.5
108.3 2.0
152.0 2.5
201.7 3.0
2. An air stream at 50°C having a humidity H=0.0030kg H2O/kg dry air is cont-
acted in an adiabatic saturator with water. It is cooled and humidified to 90%
saturation. What are its final values of humidity and temperature? (10%)
A water vapor-air mixture having a dry bulb temperature of T=50°C is passed
over a wet bulb thermometer and the wet bulb temperature is found to be
29.5°C. What is the humidity of the mixture? (10%)
(Please mark on the attached chart)
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