The Mathematical Simulation of a Three-Feed Demethanizer-Absorber

Abstract

The steady state and dynamic behaviour of a demethanizer-absorber have been studied using the IBM 7040 computer. The model considers as many as 10 components and 30 ideal trays, and three feeds to the column are permitted; this allows comparison with a real column in the Polymer Corporation plant in Sarnia. The steady state solution is obtained using the Thiele-Geddes calculational procedure and the θ-method of inducing convergence. In addition other means of ensuring convergence have been extended and tested. The transient model was studied using a third-order Runge-Kutta process. Although successful, this method was extremely slow. Equilibrium constant data in numerical form based on the Braun charts have been presented and tested. The enthalpy correlations of Yen and Alexander have also been examined and used.