Modeling and Simulation of Molecular Distillation Process for a Heavy Petroleum Cut

Modeling and simulation of molecular distillation to split of heavy petroleum cuts are proposed. A theoretical study of this problem is illustrated for a heavypetroleum cut divided into six pseudo-components. In the process simulation, a falling film is considered. The mathematical model comprises equations for the evaluation of the physicochemical properties, in order to characterize the distilled mixture. Heat and material balances on the liquid film are numerically solved by using a central finite-difference method. The simulation is carried out at the steady-state conditions, where the relevant process variables, such as film thickness, evaporation rate, film surface temperature, concentration profiles, and amount of distillate flow rate are computed. In molecular distillation, the concentration of the most volatile components shrinks in both axial and radial directions, especially due to the fast increase of the temperature in the falling film. As a consequence, the less volatile components of the liquid mixture undergoes a fast increase on the liquid interface, by clearly showing the potentialities of the molecular distillationprocess in separating heavy petroleum cuts. As the results show, the inlet variables such as the feed temperature and the feed flow rate largely influence the final composition of the condensate flow.