Development of a Thermodynamic Engine in OpenModelica

OpenModelica, an open source equation oriented modeling environment for steady state and dynamic simulation, lacks good chemical engineering support. This problem is addressed by making available in different ways the thermodynamic library Chemsep that comes with DWSIM, an open source sequential modular steady state simulator. Only slow speeds could be achieved through a Python-C API based interface connecting OpenModelica with the thermodynamic library. A socket programming based interface helps achieve faster speeds. Best results have been achieved by porting the thermodynamic library and the calculation routines to OpenModelica, due to two reasons: (1) thermodynamic equations are solved simultaneously with mass and energy balances (2) overheads in calling the external routines of DWSIM are eliminated. Performances of the above mentioned three approaches have been validated with steady state and dynamic simulations. Benzene toluene separation, methanol ethanol water distillation, and steam distillation of an n-octane ndecane mixture, have been carried out through these simulations. This work makes available a powerful simulation platform to the chemical engineering.