THE SIMULATION OF MULTI-COMPONENT DISTILLATION

A new method is proposed for the simulation of multi-component petroleum distillation columns. This method takes advantage of the power of mathematical programming techniques for c mputing the equilibrium states of physiochemical processes. The form l procedure was proposed and developed for other chemical systems, but it is perfectly general, b ing able to incorporate changes of phase, external sources or sinks of mass or energy, and differential equations which describe system dynamics if they are relatively slow with respect to the chemical dynamics. Using a theorem of the mathematician Gibbs, a chemical equilibrium may be defined in terms of the thermodynamic free-energy of each of the components. At equilibrium, the sum of the free energies will be minimized. A free energy (nonlinear) function is define and then minimized under the natural physical (linear) restraints of the system. On the analog computer chosen because of the ease of representing the system dynamics and (nonliion columns by using an analog computer.AR) heat and mass balance equations-the solution m thod is by teepest descent. A digital solution has also been deviseion columns by using an analog computer. . (Author)