Equilibrium Model: In equilibrium model, component Material balance equations, the equations of phase Equilibrium, Summation equations, and Heat balance for each stage (so-called MESH equations) are solved to give product distributions, flow rates, temperatures, and so on. The development of equilibrium model is based on the following assumptions.1.Liquid on the tray is perfectly mixed and incompressible2.Tray vapour holdups are negligible3.Vapour and liquid are in thermal equilibrium but not in phase equilibrium