Chapter 13 Flashcards
Distillation
Is the separation of 2 or more miscible volatile liquids based on their boiling points
What is the first law of a distillation tower
At constant pressure composition sets the boiling points
What is the hieght of the tower based on
Determined by the difference in boiling points of the key components being separated
How is the diameter of the distillation tower set
The feed rate and composition
What are the two things that impact the temperature of the distillation system
Composition and Pressure
Downcomer
Is the area between trays through which internal reflux flows or downspouts that allow liquid to drop down to lower trays
Gap
Is the distance between downcomer and next tray
Weir
Holds the level on the tray
Heavy ends
Are higher boiling point components
Light ends are
Lower boiling point components
Incipient flood
Foaming due to high vapor velocity up the column it fills between the trays and the column stripping section and is caused by firing reboiler to hard
Liquid flood
Vessel fills due to poor material balance
Sieve trays
Are metal plates with holes
Valve trays
Most efficient tray type, expensive, good turndown
Bubble cap trays
Efficient tray type, expensive, sturdy, heavy
Bubble point
The Temperature of a liquid on the trays. Bubble point is when liquid forms the first bubble of vapor and begins to evaporate
Froath
Normal bubbles above tray liquid
Foam
Unwanted bubbles, hard to break, and can cause incipient flooding
Reboiler
Vapor maker
Tower driving force
Reboiler vapors
Tower differential pressure
Bottom pressure minus the overhead pressure
Overhead receiver
Reflux drum
Binary distillation
Two component distillation
Fractionator
Distillation column with mutiple products and components
Reflux
Condensed overheard product that is pumped back into the top of the tower to increase product purity and temperature control
Downcomer flooding
Occurs when liquid flow rate in the tower is so great that it flows back in downcomer and over flows upper trays
Bottom products
Heavier components of the distillation process fall to the bottom of the tower and is removed as product
Distillate
The condensate taken from the distillation tower
Slump
When liquid drops to the bottom of the column
Overloading
Operating a column at maximum conditions
Flash zone
Where the feed enters
Feed/ effluent exchanger
Where the heat is exchanged between feed and bottom flow
Rectification section
Upper section where the higher concentration of molecules is located
Stripping section
Below the feed line where the heavies are located
Temperature gradient
Progressively decreasing temperatures from the bottom of the column to the top
Weeping
When the vapor velocity is to low to prevent liquid from flowing through the holes in the tray instead across the tray
