Fractional Distillation Column Design

Fractional distillation or fractionation however is in fact a special type of distillation and as a separation technique is much more effective than simple distillation and more efficient.

Fractional distillation column design. The first column is known as the extractive unit. Fractional distillation is the most common form of separation technology used in petroleum refineries petrochemical and chemical plants natural gas processing and cryogenic air separation plants. A fractionating column or fractional column is an essential item used in the distillation of liquid mixtures to separate the mixture into its component parts or fractions based on the differences in volatilities. To design fractional distillation column first we need to decide the design parameters.

Since this material can t be distilled over it is desirable to keep this as small as possible in a column design. Distillation column is above atmospheric pressure. A crude feed composition. To design distillation column we need have some data like.

General information equipment design extractive distillation involves an additional species that acts as a solvent to change the relative volatility of one of the components of a mixture. Fractionating columns are used in small scale laboratory distillations as well as large scale industrial distillations. The animation below shows the typical two column design. Fractional distillation an erlenmeyer flask is used as a receiving flask.

In most cases the distillation is operated at a continuous steady state new feed is always being added to the distillation column and products are always being removed. A fractional distillation system usually achieves several different products at multiple points within the column. Here the distillation head and fractionating column are combined in one piece. In effect fractionation is equivalent to a series of distillations where the separation is achieved by successive distillations or repeated.

Fractional distillation in a laboratory makes use of common laboratory glassware and apparatuses typically including a bunsen burner a round bottomed flask and a condenser as well as the single purpose fractionating column. If the column pressure required to accomplish overhead condensation with cooling water is less than 250 lb in2 then the column pressure should give an average temperature driving force of 5 15 c in the overhead condenser. B crude state vapor or liquid c required distillate product purity. Packed and tray columns typically have a much higher holdup than vigreux or spinning band columns.

A distillation column is sometimes referred to as a fractional distillation column in industry.