2. THEORETICAL FOUNDATIONS

2.3. Columns plates

2.3.2. Graphic calculation

To calculate the number of theoretical plates should be done from a graphical representation of equilibrium diagrams, where the design should be an integrated part containing the solvent and inert gas.

The number of theoretical plates can find staggered to the equilibrium diagram, as long as data are correct balance and are well represented in the diagram.

Figure 2.8: Example of the graphic calculation of the number of theoretical plates.

Source: www.plantasquimicas.iespana.es

The figure above shows an example of calculating the number of theoretical plates needed, using a graphical representation. This example has a system of 5 theoretical plates where you can observe the process of escalation from the equilibrium diagram.

The starting point is expressed by P0, where represents the compositions of entering fluid and the leaving gas to the top of the column. By making the fifth staggering, reach the point FP that represents the compositions of the gas supply, which is rich in solute and fluid compositions, which also rich in solute.

Once you have set the number of plates, to find out the composition of the gas and the temperature at the top of the column is found by pre-emption.

This procedure applies whether you have an insoluble inert gas in the gas phase or a non volatile solvent in the liquid phase.