Basic MESH Equations of Rigorous Distillation

The rigorous methods thus convert a column to a group of variables and equations. The equations were first referred io as the MESH equations by Wang and Henke (24). The MESH variahles are often referred to as state variables. These are 

The summation equation. The Summation equation or composition constraint simply states that the sum of the mole fractions on each stage is equal to unity. For the liquid phase, 

The equilibrium constant, Ky, can be complex function itself, dependent on Xy and y 

j VJLj is termed the stripping factor, Sy, while LJKy Vj is termed he absorption factor, Ay. The stripping and absorption factors have been used since the earliest absorber and distillation methods. 

The component balances. A great effort in all rigorous methods is in solving the component balances. Proper construction of the equations and choice of numerical method is important. For a simple column single feed, no side products), the overall component balance equation 

---