## How do you calculate relative volatility?

Strictly, the relative volatility is the ratio of K factors for the components, where for each component, i, Ki = yi/xi. For ideal components, K1/K2 = P1/P2.

What does Fenske equation determine?

The Fenske equation in continuous fractional distillation is an equation used for calculating the minimum number of theoretical plates required for the separation of a binary feed stream by a fractionation column that is being operated at total reflux (i.e., which means that no overhead product distillate is being …

What is Gilliland equation?

An empirical equation used to estimate the number of stages required in a distillation column. It uses the minimum number of stages as well as minimum and actual reflux ratios in the calculation. It is named after American chemical engineer Edwin Gilliland (… …

### What is Alpha in Fenske equation?

αt. = relative volatility of light key to heavy key at top of column. αb. = relative volatility of light key to heavy key at bottom of column. The above Fenske equation can be modified for use in the total reflux distillation of multi-component feeds.

What relative volatility tells us?

Relative volatility is a measure comparing the vapor pressures of the components in a liquid mixture of chemicals. This quantity is widely used in designing large industrial distillation processes.

What is the Fenske-Underwood-Gilliland method?

The mathematical model of the column is obtained by performing a total mass balance and partial mass balances to component “ i .” The Fenske-Underwood-Gilliland method is used to find the functional relationship between the compositions of the bottom and the dome of the column.

#### What is Gilliland correlation?

[gə′lil·ənd ‚kä·rə‚lā·shən] (chemical engineering) Approximation method for distillation-column calculations; correlates reflux ratio and number of plates for the column as functions of minimum reflux and minimum plates.

What is the significance of the relative volatility α in a distillation process?

VLE: Relative Volatility. In order to separate a binary mixture using distillation process, there must be a differences in volatilities of the components. The greater the difference, the easier it is to do so. A measure for this is termed the relative volatility.

What is the Fenske equation in continuous fractional distillation?

Fenske equation. The Fenske equation in continuous fractional distillation is an equation used for calculating the minimum number of theoretical plates required for the separation of a binary feed stream by a fractionation column that is being operated at total reflux (i.e., which means that no overhead product distillate is being withdrawn from…

## What is the origin of the Fenske equation?

The equation was derived in 1932 by Merrell Fenske, a professor who served as the head of the chemical engineering department at the Pennsylvania State University from 1959 to 1969.

What is relative volatility of a mixture?

For a liquid mixture of two components (called a binary mixture) at a given temperature and pressure, the relative volatility is defined as When their liquid concentrations are equal, more volatile components have higher vapor pressures than less volatile components.

What happens when the volatilities of both components are equal?

When the volatilities of both key components are equal, = 1 and separation of the two by distillation would be impossible under the given conditions because the compositions of the liquid and the vapor phase are the same ( azeotrope ). As the value of increases above 1, separation by distillation becomes progressively easier.