Distillation Theory The Basics of Distillation Different Parts

Distillation Theory

The Basics of Distillation

Different Parts of Distillation Condenser Overhead Vapor Overhead Product Rectifying Section Stripping Section Reflux Reboiler Bottoms Product

Possible Feed Conditions

Mc. Cabe-Thiele Graphical Method

Minimum Reflux Ratio

Optimal Feed Stage

$Shortcut Method • Fenske equation-minimum number of trays and split fraction$

Shortcut Method • Fenske equation-minimum number of trays and split fraction

Tray Number and Reflux Ratio

Stage Efficiency • Range from 41% to 88% • For close-boiling mixtures, liquid viscosity is low, resulting in high stage efficiency

Distillation Column Sizing • Calculate column Diameter by Internal flowrates and design column at 80% of linear flooding velocity. • If D> 3 m = Parallel columns

Types of Distillation Columns • Packed Bed Columns § Used more often for absorption and distillation of vapor-liquid mixtures. § The liquid flows downward through the packing and the vapor flows upward through the column. • Advantages § Cost efficient § Lower pressure drop § Good for thermally sensitive liquids • Disadvantages § Packing can break during installation

Types of Distillation Columns • Tray Column § The number of trays or stages is dependent • Advantages § Cost efficient § Can handle high liquid flow rates • Disadvantages § Higher pressure drops than packed columns § Foaming can occur due to agitation

Advanced Distillation Extractive Distillation Reactive Distillation Vacuum Distillation

References • Seader, J. D. , Ernest J. Henley, and D. Keith. Roper. Separation Process Principles: Chemical and Biochemical Operations. 3 rd ed. Hoboken, NJ: Wiley, 2011. Print. • "ENCYCLOPEDIA OF CHEMICAL ENGINEERING EQUIPMENT. " Distillation Columns. N. p. , n. d. Web. 11 Feb. 2015. http: //encyclopedia. che. engin. umich. edu/Pages/Separations. Chemical/Distil lation. Columns/Distillation. Columns. html. • Biegler, L. , Grossmann, I. , Westerberg , A. , 1997, Systematic Methods of Chemical Process Design, Prentice Hall. • Bravo, Jose L. and James K. Fair. "Distillation Columns. " Chemical Engineering Progress January 1990: 19 -29.