Fractional Distillation: Ponchon-Sovarit Method

Question 1

Known as Ponchon-Savarit Method.

Answer 1

Enthalpy-Concentration Method

Question 2

True or False.
Heat Effects and Heats of Solution is negligible in Ponchon-Savarit Method.

Answer 2

False. It is not negligible.

Question 3

True or False.
If the Enthalpy-Concentration Data of a binary system is available, the Ponchon-Savarit Diagram is pretty easy to plot.

Answer 3

True

Question 4

True or False.
In Ponchon-Savarit, the reference temperature To is often taken as equal to the boiling point of the lower-boiling component A.

Answer 4

True.

Question 5

The vapor leaving the top of the column is brought to a total condenser to produce a saturated liquid stream.

Answer 5

Enriching Section

Question 6

Part of the saturated liquid product returned to the column to maintain a countercurrent operation.

Answer 6

Reflux

Question 7

The withdrawn liquid product in enriching section for further processing.

Answer 7

Distillate

Question 8

It represents the net enthalpy of passing streams.

Answer 8

Difference or Net Flow Point

Question 9

The point whose coordinate are (hd-qd,xd)

Answer 9

Difference or Net Flow Point

Question 10

What equation represents a three-point equation of a straight line on a Ponchon diagram?

Answer 10

[(hd-qd) - Hn-2]/(xd - yn-2)=(Hn-2 - hn-1)/(yn-2 - xn-1)

Question 11

True or False.
Once the difference point P’ is located, all passing streams between any two stages lie on a line that cuts the phase envelopes and terminates at point P’’.

Answer 11

True

Question 12

True or False.
If equilibrium liquid and vapor are saturated, their compositions are determined by the points at which the material balance line cuts the liquid and vapor phase envelopes.

Answer 12

True

Question 13

The internal reflux ratios L/V for each stage of the column can be expressed in terms of the ________________________.

Answer 13

Line segment and coordinates

Question 14

The withdrawn liquid product in stripping section for further processing.

Answer 14

Bottoms

Question 15

The liquid leaving the bottom of the column is brought to a reboiler to produce saturated vapor and liquid products.

Answer 15

Stripping Section

Question 16

The saturated vapor is returned to the column to maintain a _____________ arrangement.

Answer 16

Countercurrent

Question 17

The difference point for the stripping section.

Answer 17

Point P’’

Question 18

The ratio of liquid to vapor between stages m and m-1

Answer 18

Point P’’

Question 19

True or False.
All operating lines in the stripping section pass through P’’ and that the composition of any two saturated passing streams are marked by the points where the straight line through P’’ cut the phase envelopes.

Answer 19

True

Question 20

Section: Enriching
Line Segment: P’B

Answer 20

Heat Removed in Condenser per pound of Distillate

Question 21

Section: Enriching
Line Segment: CP’/EP’

Answer 21

L/V General

Question 22

Section: Enriching
Line Segment: AP’/BP’

Answer 22

L/V on top plate (internal reflux ratio)

Question 23

Section: Enriching
Line Segment: AP’/AB

Answer 23

L/D on top plate (external reflux ratio)

Question 24

Section: Stripping
Line Segment: P’’G

Answer 24

Heat added in reboiler per pound of bottoms

Question 25

Section: Stripping
Line Segment: MP’’/KP’’

Answer 25

L/V (w/ bar line) general

Question 26

Section: Stripping
Line Section: MP’’/MK

Answer 26

L/B (w/ bar line) general

Question 27

Section: Overall
Line Segment: P’P’’/FP’’

Answer 27

F/D

Question 28

Section: Overall
Line Segment: FP’’/FP’

Answer 28

D/B

Question 29

It corresponds to a situation where there is no feed, distillate, or bottoms and where the minimum number of stages is required to achieve a desired operation.

Answer 29

Total Reflux

Question 30

The operating lines for each section of the column thus become straight vertical lines and the minimum number of stages is calculated in the diagram.

Answer 30

Total Reflux

Question 31

The minimum number of stages is required and F=0, B=0, D=0, therefore the points (hd - qd,xd) and (hb - qb,xb) lie at infinity.

Answer 31

Total Reflux

Question 32

The first step in determining the minimum reflux ratio is to use _______________.

Answer 32

Feed condition

Question 33

True or False.
The minimum reflux ratio in the enriching section is set by the highest intersection made by the steepest tie line in the section with the line x=xd/.

Answer 33

True