T or F: Because the enriching section of a distillation column has higher concentrations of the less volatile product in it, it tends to be the cooler portion of a distillation system.
False
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T or F: For a distillation column, the lower the reflux ratio, the lower the utility costs for proper operation.
True
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3
T or F: In a typically used industrial distillation column, the liquid surface is boiling violently and is well mixed which is not true for the vapor phase.
True
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4
Distillation is possible only of the solution components are ___ a. volatile b. non-volatile c. cryogenic d. none of the mentioned
volatile
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5
If the vapor pressure of the two components in a binary mixture is same, then it is a _____ a. isotope b. azeotrope c. differential boiling point d. none of the mentioned
azeotrope
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6
The use of vapor produced from the reboiler is ____ a. to strip out more volatile component from liquid b. to strip out less volatile component from the liquid c. to increase the temperature of the fractionator bottom d. none of the mentioned
to strip out more volatile component from liquid
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The reflux of liquid produced from the condenser is ___ a. to strip out more volatile component from vapor b. to strip out less volatile component from the vapor c. to decrease the temperature of the fractionator top d. none of the mentioned
to strip out less volatile component from the vapor
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8
The light key components are ____ a. more volatile b. less volatile c. non volatile d. none of the mentioned
more volatile
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9
The heavy key components are ____ a. more volatile b. less volatile c. non volatile d. none of the mentioned
less volatile
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10
If the feed enters the distillation column at its dew point, then the slope of the feed line is _____ a. infinity b. 0 c. 1 d. between 0 and 1
0
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11
If the feed enters the distillation column at its boiling point, then the slope of the feed line is ____ a. infinity b. 0 c. 1 d. between 0 and 1
infinity
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12
What is the location of the condenser in the figure? a. P b. R c. S d. no condenser
P
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13
At total reflux, a. residue is 0 b. distillate is 0 c. reflux is 0 d. all of the mentioned
distillate is 0
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14
The point where the operating line and the equilibrium line meet in distillation methods is known as ___ a. plait point b. Q point c. pinch point d. none of the mentioned
pinch point
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15
Gilliland Correlation is arranged to estimate the ___ a. numbers of stages b. numbers of reboiler c. numbers of feed d. numbers of column
numbers of stages
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16
Once the components are identified, in a multicomponent distillation they are called ___ a. key components b. mixed components c. flow components d. gain components
key components
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17
Raising the column pressure results in ____ a. lower relative volatility b. higher relative volatility c. no effect d. decreased throughput
lower relative volatility
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18
At minimum reflux, number of stages is a. unity b. infinite c. minimized d. negative
infinite
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19
In a binary system, the higher the concentration of the less volatile species in the feed to a flash drum: a. the higher the liquid flow rate leaving the drum b. the higher the vapor flow rate leaving the drum c. the larger the flash drum d. cannot determine
The higher the liquid flow rate leaving the drum
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20
The value of Ki can be expressed as: a. yj/xi b. yi/xj c. xi/yi d. yi/xi
yi/xi
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21
The relative volatility of components i and k can be defined as: a. Ki/Kj b. K/Kj c. yi/y d. xi/x
Ki/Kj
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22
The energy balance around a distillation column is given by: a. F*hF + Qc + Qr = D*hD + B*hB b. F*hF - Qc + Qr = D*hD + B*hB c. V1*H1 + Qc = L0*h0 + D*hD d. V1*H1 - Qc = L0*h0 + D*hD
F*hF + Qc + Qr = D*hD + B*hB
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23
The material balance around the condenser is given by: a. F = D - B b. F = D + B c. V = L + D d. V = L - D
V = L + D
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The reflux ratio can be defined as: a. V/L b. D/L c. V/B d. L/D
L/D or L0/d
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25
The slope of the top operating line in distillation is: a. V/L b. L/V c. Vbar/Lbar d. Lbar/Vbar
L/V
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26
The intercept of the bottom operating line in distillation is: a. Lbar/Vbar b. Vbar/Lbar c. 1 - Lbar/Vbar d. 1 + Lbar/Vbar
1 - Lbar/Vbar
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27
HETP stands for: a. height of efficient total packing b. height equivalent to theoretical plate c. height expected to product d. high energy thermal plasma
height equivalent to theoretical plate
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28
Column diameter is most dependent on: a. tray type used b. reboiler duty c. liquid velocity d. vapor velocity
vapor velocity
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29
Which of the following is used when determining tray spacing? a. propensity of liquid to foam/entrain b. need for person to access top of trays c. a&b d. none of the above
propensity of liquid to foam/entrain need for person to access top of trays
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30
The phenomena of the flowing liquid toward the wall of tower and dispersed in lateral direction is called ___ a. channeling b. flow casting c. entraining d. regimens
channeling
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31
As a rule of thumb, the overall efficiency is: a. 0.1 to 0.3 b. 0.3 to 0.5 c. 0.5 to 0.7 d. 0.7 to 0.9
0.5 to 0.7
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32
When sizing a column, switching for trays to packing usually results in: a. increased height b. decreased height c. no change in height d. no change in trend
decreased height
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33
The higher the concentration of volatile species in the feed to a flash drum: a. the higher the liquid flow rate b. the higher the vapor flow rate c. the larger the flash drum d. cannot determine
the higher the vapor flow rate
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34
The overall material balance for a flash drum is: a. F = V - L b. F = V/L c. F = V + L d. F = F * L
F = V + L
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35
For multi-component flash distillation, the equation used for iterative solving is the a. Michaelis-Menten b. Monod c. Van der Waals d. Rachford-Rice
Rachford-Rice
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The overall material balance for a distillation column is: a. F = D - B b. F = D + B c. V = L + D d. V = L - D
F = D + B
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37
When heat is supplied to bottom of liquid stage to vaporize a portion, it is called: a. condensing b. boil-up c. cooling d. desalting
boil-up
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38
When a portion of the overhead product is returned to the column, it is called: a. reflux b. dew point c. boil-up d. relative BP
reflux
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39
The energy balance around the condenser is given by: a. F*hF + Qc + Qr = D*hD + B*hB b. F*hF - Qc + Qr = D*hD + B*hB c. V1*H1 + Qc = L0*h0 + D*hD d. V1*H1 - Qc = L0*h0 + D*hD
V1*H1 + Qc = L0*h0 + D*hD
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40
The quality of feed represents: a. The fraction of liquid in the feed b. The fraction of vapor in the feed c. The apparent fraction of liquid in the feed d. The apparent fraction of vapor in the feed
The apparent fraction of liquid in the feed
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41
The fraction of the feed represents: a. The fraction of liquid in the feed b. The fraction of vapor in the feed c. The apparent fraction of liquid in the feed d. The apparent fraction of vapor in the feed
The apparent fraction of vapor in the feed
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42
Which of the following is NOT necessarily true for Constant Molar Overflow? a. the volume flows are constant b. the molar flows are constant c. the heat of vaporization is constant between stages d. the heat capacity is constant between stages
the volume flows are constant
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43
Total reflux condition at steady-state means that: a. D = 0 b. B = 0 c. F = 0 d. all of the above
D = 0, B = 0, F = 0
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44
Minimum reflux is the point where: a. reflux is zero b. bottoms flow is maximized c. the separation can be completed with an infinite number of stages d. reflux = distillate
the separation can be completed with an infinite number of stages
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45
process of separating components based on differences in volatility
distillation
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product of a distillation separation containing the majority of the more volatile components coming from the top of the unit
distillate
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the product of a distillation separation containing the majority of the less volatile components coming from the bottom of the unit
bottoms
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48
the ratio of the condensed overhead vapor flow that is returned to the column vs the amount that is taken off as product (L/D)
reflux ratio
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49
Order the following from most volatile to least volatile: propane i-pentane n-pentane methane
methane propane i-pentane n-pentane
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50
What are the two state variables you can adjust in flash distillation to change the composition of the product streams?
drum pressure and feed temperature
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51
What are the four flow regimes possible in distillation?
bubble, foam, froth, and spray
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52
For the light key component, equilibrium relation is a .yK=x b. Kx=y c. depend upon trays d. cannot be specified
Kx=y
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53
If the fractional recovery of light key in the distillate is FR, then the light key in the feed is a. DxD=(FRD)+FxLK b. DxD=(FRD)-FxLK c. DxD=(FRD)FxLK d. DxD=(FRD)
DxD=(FRD)FxLK
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54
For multi-component systems, Fenske Method gives a. minimum reflux b. minimum strip c. maximum reflux d. minimum trays
minimum trays
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55
For multi-component systems, Underwood Equations gives a. minimum reflux b. minimum strip c. maximum reflux d. minimum trays
minimum reflux
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56
The component balance of the more volatile component is given as a. FzF=DxD+BxB b. FzF=DxD-BxB c. FzF=DxD/BxB d. FzF=DxD*BxB
FzF=DxD+BxB
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57
A pinch point may occur at intersection of feed line and a. stream line b. stripping line c. rectifying line d. equilibrium line
equilibrium line
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58
The real number of trays are obtained as a ratio of a. number of ideal trays and flow rate b. number of ideal trays and efficiency c. number of ideal trays and reflux ratio d. number of ideal trays and stripping ratio
number of ideal trays and efficiency
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59
Which of the following is an important assumption of McCabe Thiele method? a. heat loss is maximum b. heat loss is negligible c. heat loss is infinite d. cannot be specified
heat loss is negligible
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60
Which is a proper form of Henry's Law? a. Ptot=Hb*xb b. yb=Hb*xb c. yb=Hb/xb d. Pb=Hb*xb
Pb=Hb*xb
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61
Which is represented by the figure? a. stripper b. scrubber c. heat exchanger d. three-phase extractor
scrubber
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62
Which is represented by the figure? a. stripper b. scrubber c. heat exchanger d. three-phase extractor
stripper
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63
A scrubber is designed to a. remove contaminant from liquid phase b. remove contaminant from gas phase c. separate two liquids d. dissolve solid in gas phase
remove contaminant from gas phase
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64
A stripper is designed to a. remove contaminant from liquid phase b. remove contaminant from gas phase c. separate two liquids d. dissolve solid in gas phase
remove contaminant from liquid phase
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65
How many trays are represented in the drawing? a. 0 b. 1 c. 2 d. 3
2
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66
If the fractional recovery of light key in the distillate if FR,D, then the amount of light key in the distillate is
FR,D-F*z,LK FR,D+F*z,LK FR,D*F*z,LK
FR,D*F*z,LK
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67
Place these in order of least to most expensive separation structure
Random packing Bubble cap Structured packing Valve tray Sieve tray
Sieve tray Valve tray Bubble cap Random packing Structured packing
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68
Column height depends on
number of trays tray type reboiler duty reflux ratio
number of trays
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69
Column diameter is most dependent on
tray type used reboiler duty liquid velocity vapor velocity
vapor velocity
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70
Operating velocity should be ____ flooding velocity
greater than less than equal to
less than
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71
Packed columns are generally
taller and thinner shorter and thinner taller and wider shorter and wider
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