Drastic reduction of computing time in dynamic simulation for hydrogen isotope distillation columns

An efficient dynamic simulation code for hydrogen isotope distillation columns is developed. Because of the great dimensionality and stiffness of the basic ordinary differential equations to be integrated, the long computing time required is often the major stumbling block in computer simulation work for column dynamics. Publicly available integration algorithms are reviewed and some are tested. The Ballard-Brosilow algorithm is chosen as the most attractive one in terms of both stability and simplicity. The algorithm requires only solution of linear tridiagonal equations and scalar bubble point calculations at every time step. Replacing the improved Euler algorithm in the previous code by the Ballard-Brosilow algorithm and determining an adjustment method for the time step size, the resultant computer code presents a remarkable success: A typical numerical example simulating column dynamics from a steady state to another indicates that the calculational results can be obtained with engineering accuracy in about two orders of magnitude shorter computing time