19 th European Symposium on Computer Aided Process Engineering – ESCAPE19 J. Je˙ zowski and J. Thullie (Editors) c  2009 Elsevier B.V./Ltd. All rights reserved. Dynamic simulation of Chemical Engineering systems us- ing OpenModelica and CAPE-OPEN Carl Sandrock a and Philip L. de Vaal b a University of Pretoria, Pretoria, 0171, South Africa, carl.sandrock@up.ac.za b University of Pretoria, Pretoria, 0171, South Africa, philip.devaal@up.ac.za Abstract Modelica has emerged as a strong contender in the arena of dynamic simulation lan- guages. It was developed to be a standard, with an open specification and a large and usable standard library. OpenModelica is an Open Source implementation of a Modelica compiler and environment which is being developed actively. Modelica’s object-oriented design makes it easy to develop chemical engineering unit operations and connect them to one another. Unfortunately, most proprietary databases of thermodynamic and physical properties and reaction data are not supplied in equation form, but rather as part of closed software. This means that such data must be exchanged with the programs that contain them if they are to be used in custom simulation codes. The CAPE-OPEN specification provides a standard architecture for these exchanges, in addition to support for incorporating new unit operations or algorithms into existing pro- prietary simulations. In this study, a Modelica library allowing interface between Modelica and CAPE-OPEN is developed. Its functionality is demonstrated using a model of a ten plate distillation col- umn simulated in OpenModelica on a Linux machine, with thermodynamic and property data from Honeywell Unisim on a Windows machine. The data interfacing was done over a TCP/IP network using CORBA. It is found that real-time operation is possible, but that network overhead makes up a significant fraction of the running time, posing problems for faster-than-realtime off-line simulation and optimization. Keywords: Simulation, modelica 1. Introduction Flowsheeting has assumed a central position in modern process engineering practice. Di- agrams describing the flow of material and energy through a plant are the main mode of communicating process design and several packages exist that solve the associated equa- tions. Steady state flowsheeting is accepted in industry to such an extent that it is unlikely that a chemical plant of any size is designed without the use of at least one such tool. [3] Market penetration of dynamic simulation is lagging behind that of steady state simu- lations, partly due to the computational requirements associated with such simulation and partly due to the considerable additional effort involved in developing dynamic sim- ulations. However, interest has increased in the development of dynamic plant sim- ulations. In addition to dedicated process engineering tools like Aspen, ChemCAD, HYSYS/Unisim (Honeywell’s Unisim software is based on HYSYS), ProSim and SimSci,