Computer Simulation of a Multicomponent, Multistage Crude Distillation Process

Abstract

A computer program was created to solve the material and energy balance equations simultaneously for a crude distillation column. The model is designed to handle hypothetical hydrocarbon components, allowing for the simulation of crude oils which are usually made up of unknown components. The accuracy of the model depends to some extent upon the accuracy of the crude characterization and the number and size of fractions used in that characterization. The model incorporates a second liquid phase, water, if it exists and allows for solution of sidestream strippers and pumparounds which are almost always used in crude distillation. The solution technique is a modified NewtonRaphson technique using the method of Newman for inverting and solving the Jacobian. The model has been used to simulate crude distillation columns for a variety of crude oils and compared to existing operating data available on crude distillation columns. The model was found to be successful when comparing liquid rate and temperature profiles to those obtained from test run data. Improvements in storage and convergence techniques will allow use of this model for solution of crude columns with microcomputers.