Research On Dynamic Modelling And Simulation Of Complex Petroleum Distilation Column

Distillation column is the most important equipment used in petroleum separation process, due to its large scale, high energy consumption and complex operation, and study on dynamic characteristic of petroleum distillation column has an important significance in production practice and distillation theory. However, distillation column itself is a complex system which involves the calculation of petroleum thermodynamic properties and has more complex structure than a general column.In this paper, by the analysis of the current research status, several improved methods are presented for dynamic modeling and simulation of petroleum distillation column. The main contents are listed as follows:(1) To sovle the problem of dynamic operation simulation of feed switching, a petroleum characterization method based on standard pseudo-component is proposed, which uses light oil and heavy oil as two groups of standard pseudo-components whose mass fraction are calculated by the True Boiling Point (TBP) curve, the single traditional pseudo-component is represented equivalently by two standard pseudo-components.(2) Since non-equilibrium stage models have very complex mathematic model formation and time-consuming computation, a vapor flow correlation is proposed to calculate the instantaneous vapor flow rate leaving a tray directly, then a general distillation column model is established combined with the classic equilibrium stage model method.(3) A general petroleum distillation column dynamic simulation system (petroDSim) is developed using above proposed new model and standard pseudo-component method, by means of powerful numerical calculation function of Matlab and the support of Simulink on dynamic simulation.The dynamic processes of several common crude distillation columns modeled by the new method are studied, the results show that the model is able to simulate the dynamic operations of distillation columns accurately, quickly and robustly, and has very strong adaptability in changing feed species or compositions. The efficient dynamic model could also be applied for developing advanced control and dynamic optimization of the crude distillation processes.