Separation Processes Flashcards
Ideal or Perfect Leaching
No inert is included in the extract
LEACHING
Composition of
1. Solution
2. Underflow
- Solution = Solute + Solvent
- Underflow = Solution + Inert
Underflow = Liquid + Solid
LEACHING
Constant Solution Retention
R = M sol’n / M inert
x or y = M solute / M sol’n
LEACHING
Equilibrium
y1 = x1
LEACHING
Tiller-Tour Equation
Determination of Stages
. log (x1 - y2 / xN - yN+1)
N = ————————————- +1
log (x1 - xN / y2 - yN+1)
Remember to add 1
Vertical X and Y
1 2 N, and N add 1.
Horizontal X and Y.
Swap XN, Y. and add 1.
LEACHING
y2
Determination of Stages
y2 = L/V (x1 - xN) + yN+1
Yellow two, length over velocity. Removen the Xs and add the Y with one side chick.
LEACHING
Efficiency
N, theo
η = ———————
N, actual
Always round N off to a whole number
LEACHING
Mass fraction of the solute in the extract in a constant solvent retention means
x or y = M solute / M solvent
it is not y1
MASS RATIO:
ex. mass fraction is …. 0.6; x1=y1=0.6V1/04.V1
LEACHING
- Counter-current
- Co-current
Leaching
(1)
V1 ←| |← V2
L0 →| |→ L1
(2)
S
↓
F →| |→ L
↓
V
V = y ; Extract
L = x ; Raffinate
LEACHING
When solving, always start with
Equilibrium: y1 = x1
-> a/V1 = F, solute - a/L1
Inert as basis if Retention is given and no feed amount is mentioned
Applicable in Counter current and Co-current systems
Rose oil is extracted from rose leaves using _____ distillation
Steam Distillation
When the solvent dissolves very little of solute then
large quantity of solvent is required to extract the solute
An ideal single stage extraction process is used to treat 100 mol/s of an organic feed solution. The solute concentration in this solution is to be reduced from 0.5 mol% to 0.1 mol%. A pure solvent S is used. To reduce the solvent requirement by half for the same separation
use another pure solvent S* whose partition coefficient is twice that of S
The triangle whose one corner coincides with the enriching line and the outer corner is on the stripping line is called the
Feed Plate
Flash distillation is suitable for the separation of components
having very wide boiling points.
Relative volatility varies with the concentration of component for an ideal solution. The relative volatity of a binary mixture may be defined as the ratio of vapor pressure of component ‘A’ to that of component ‘B’, when
vapor phase obeys Dalton’s law and liquid phase obeys Raoult’s law.
Leaching of coarse solid lumps is also termed as
Percolation
Large scale usage of flash distillation is practiced in
petroleum refinning
In an operating distillation column, the
driving force for the vapor flow is the pressure drop, as the pressure decreases gradually from the bottom to the top of the column.
In case of steam distillation, the steam leaving the liquid is not completely saturated with distillate vapor, because
mixing of steam with the material being vaporised is not so intimate as to result in equilibrium condition.
For a binary mixture distillation process, the degree of freedom is 2. However, if the pressure is fixed in this process, the number of independent variables in this process will be
1
Partition Ratio if:
1. kD > 1
2. kD < 1
- kD > 1; E/R
- kD < 1; R/E
ex. Y = 2.2 X —> CE = 2.2 CR (kD=2.2)
LLE
Shortcut Formula in getting solute A (in Raffinate) in a single/multiple stage extraction.
A,Rn = A,F (B / kD·S + B)^n
Rec = 1 - A,Rn/A,F
Rn = Raffinate in nth (last) extractor
Rec in extract
LLE
Shortcut Formula in getting solute A (in Extract) in a single stage extraction.
(Partition Ratio)
A,E / S = kD (A,R / B)
A,R = A, F - A,E
