This report deals with the transient behaviour of process systems such as those normally encountered by the chemical engineer. Two competing approaches for the numerical solution of this problem are described. The first is an "equation oriented" approach, and the second is an "equipment oriented11 or "modular" approach. The concept of modularity is discussed, and a brief presentation of its advantages is given. A program DYNSYS-B was written to apply the modular approach to transient studies. The program employs a predictor-corrector technique to solve the system's differential equations in a sequential fashion. The DYNSYS-8 program was applied to a multicomponent liquid-liquid extraction unit with heat effects and reflux, with the object of evaluating the program and gaining some experience with its use. Based on this study. we believe that the program is readily applied to the solutions of many problems. Some suggestions are made for improving the computation efficiency of the program. / Thesis / Master of Engineering (MEngr)

This report deals with the use of the "Modular Approach", in the simulation of change-over operations, for a continuous multiproduct chemical plant. A dynamic model of the continuous fat hydrolysis process was built, with the DYNSYS framework, with the purpose of evaluating the usefulness of this programme in simulating different change-over operation policies. Operator's activities were simulated making use of an interactive version of DYNSYS, demonstrating its value for studying alternate changeover policies and possible as a training device. Supervisory control was implemented in order to automate the change-over operations, simulating the functions of a small computer controlling the process. Improved operating policies for change-over are proposed and the validity of the simulation is discussed from both a practical and a theoretical point of view. / Thesis / Master of Engineering (ME)

<p> The object of this work was to evaluate the Supernova ninicomputer as a process simulation tool. To accomplish this obje c tive the GEMCS ste2dy-state simulation system wa.s programmed for the Supernova. This system was programmed to run in five different modes, BASIC , two modes which require that al.L progra1ns are written in Assembly Language, and two modes in which programs may be called from the disk. Of these latter two modes, one requires all programs to be written in Assembly Language; the other mode allows programs to be written in Assembly Language or FORTRAN IV. </p> <p> Two case studies which had previously been run on the CDC 6400 were run on the Supernova to test and evaluate f our of the modes in which GEMCS was proerammed for the Supernova. </p> <p> The studies have also provided an a ssessment of the hardware and softws.re facilities of the Supernova and the results of thjs assessment were documented. In addition the opera tion of the various strategies used to impl ement GEMCS have provided an indication of the feasibility of the impl ementation of the dynamic system simulation program, DYNSYS. </p> / Thesis / Doctor of Philosophy (PhD)