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What happens when there is an additional input side stream:
Its phase will be added to that within the column.
e.g a sidestream of pure steam would have to be added to the boilup from the reboiler.
What is constant molar overflow:
The assumption that the flowrates of passing streams is constant (will be different in stripping and rectifying sections however.)
How to work out K factors?
Can be determined from modified raoults law or Henry’s law.
Henry’s Law
K=H1/P
modified Raoult’s
K=y”P*/P
Uh equation:
Uh=Uv*(Ah/Aa)
When calculating around a distillation column what equations can be used to determine internal flowrates.
Total mass balance around the column and mass balance of the MVC, these can be combined to remove variables and give
Distillation plate numbering
Rectifying will be above feed. Stripping will be below and including the feed.
Absorption plate numbering
Top of the section is where we have mass balance.
Remember nought term is the one that will likely be 0 so liquid initial composition.
Stripping plate numbering
Bottom of the section is where we have mass balance.
Remember nought term is the one that will likely be 0 so stripping gas initial composition.
Reboiler counts as an…
equilibrium stage (plate)
How to get gradient for liquid liquid.
equate F=R and E=S, then solve mass balce in form of y2-y1/x2-x1 =m
Murphree Efficiency equation
Efficiency =AB/AC
Where AC is full length of line and AB is actual length of line.
Murphree Efficiency explanation
For each triangle drawing the height will be multiplied by the factor and so not reach the equilibrium curve.
Liquid fraction equation:
q=(y-z)/(y-x)
