Separating tower simulation calculation method for special phase equilibrium multi-component hydrocarbons

The invention aims to provide a separation tower simulation calculation method for special phase equilibrium multi-component hydrocarbons. The special phase equilibrium multi-component hydrocarbons comprise hydrogen, nitrogen, helium or methane. The method comprises the following steps of S1, determining a tower plate with special phase equilibrium through simplified model calculation; S2, simulating and correcting the simplified model of the tower plate with the special phase balance; and S3, repeatedly correcting the simplified model till the simulation calculation result of the tower plate with the special phase balance is converged. According to the method, a phase equilibrium constant K value of the gas such as hydrogen, nitrogen, helium or methane can be expressed by a simplified model under the condition that the temperature is reduced along with the rise of the temperature. The method does not depend on a good initial value, can directly use an initialization result for calculation, and is high in cal