Throughout their history, process simulation tools had to adapt to the evolutionary nature of hardware and software technologies and to an increasingly demanding market. Usage is again disturbed today by computer networks and co-operative work. In addition to the performance and user-friendliness criteria, the various tools must enable substitution one to another and exchange of services: they must be interoperable and integrable. New technologies based on software components developed with object-oriented languages are available to meet this new market requirement. The CAPE-OPEN standard accompanies that trend by providing a common interface specification for process simulation software.
Considering this situation, ProSim decided to change the architecture of its tools to answer not only its own customers' expectations, but also the whole simulation process software user community. Simulis® project fulfills that goal. Today, three software components are already available. The first one, called Simulis® Conversions, allows to manage quantities and unit conversion in an application. Next, Simulis® Properties, is a pure compound properties server. Properties can be constant or temperature dependent. A pure compound property database, containing more than 1700 compounds, is provided with this software component. The last software component, called Simulis® Thermodynamics, is presented in this paper through its use as a toolbox within MATLAB®. In the future, other components will be developped and will deal with chemical reactions and unit operations.
II. Simulis® Thermodynamics
Simulis® Thermodynamics is a thermodynamic properties and phase equilibrium calculation server for pure compounds and mixtures (containing up to 200 simultaneous compounds). It is based on well-known ProSim thermodynamic calculation library which has been validated through many years of intensive industrial use. Simulis® Thermodynamics is able to calculate the following properties and their derivatives (wrt temperature, pressure, number of moles):
· Transport properties (Cp, m, l,…).
· Thermodynamic properties (H, S, U,…).
· Compressibility properties (Z, Cp/Cv, …).
· Non-ideal properties (g, f)
· Pseudo critical properties (Tc, Pc, Vc, Zc).
And to perform the following phase equilibrium calculations:
· Liquid - Vapor (TP, HP, SP, wT, wP, UV, …).
· Liquid - Vapor phase envelope.
· Liquid - Liquid (TP).
· Liquid-Liquid-Vapor (TP, HP, wP).
Simulis® Thermodynamics model library contains the most used and relevant models as shown in the following non exhaustive list:
· Soave-Redlich-Kwong (SRK),
· Peng-Robinson (PR),
· Lee-Kesler-Plöcker (LKP),
· Benedict-Webb-Rubin modified Starling (BWRS),
· UNIFAC original,
· UNIFAC modified (Dortmund),
· UNIFAC modified (Larsen),
· UNIFAC Liquid-Liquid,
· Sour water,
· Amines and acid gases,
III. Simulis® Thermodynamics and CAPE-OPEN
Even if the Simulis® Thermodynamics architecture is not based, in native, on CAPE-OPEN standard (mainly for keeping existing codes), Simulis® Thermodynamics proposes a complete interoperability with other software implementing the CAPE-OPEN standard.
On the one hand, throughout its “socket” facility (Fig. 1), Simulis® Thermodynamics allows a client application to calculate properties and phase equilibrium using an external CAPE-OPEN thermodynamic property package coming, for example, from Aspen Properties (AspenTech), PPDS (TUV-NEL), Multiflash (Infochem), ...
Fig. 1 : CAPE-OPEN Thermodynamic "socket" facility
On the other hand, with Simulis® Thermodynamics, an end-user is able to create a CAPE-OPEN thermodynamic property package which can be used inside software of other providers: this is the CAPE-OPEN thermodynamic “plug” facility (Fig. 2). With the help of certain Simulis® Thermodynamics features, a thermodynamic expert can easily build, record and deploy a property package to his colleagues. Then, the property package can be used in all simulation tools of a company. This functionality has been successfully tested in Aspen Plus 2004 and v12.1 (AspenTech), Aspen Hysys 2004 and v3.2 (AspenTech), PRO/II v7.1 (SimSci-Esscor), gPROMS® (PSE) and Xchanger Suite 4.0 (HTRI). Additional testing in VALI (Belsim) and INDISS (RSI) is underway.
Fig. 2 : CAPE-OPEN Thermodynamic "plug" facility
Any application integrating Simulis® Thermodynamics automatically inherits this CAPE-OPEN thermodynamic compliance, both as a plug and a socket.
Finally, as shown on Fig. 3, Simulis® Thermodynamics is always there where the end-user needs it and guarantees a true thermodynamic data consistency throughout the different applications he may use.
Fig. 3 : Simulis® Thermodynamics framework
IV. "Integrability" capability of Simulis® Thermodynamics – example within MATLAB®
Now, we are focusing on an important capability of Simulis® Thermodynamics which we call "integrability". The benefit of architecture based on a component approach is that any application supporting the COM/DCOM technology (and others) can be linked and interoperate with Simulis® Thermodynamics. The standard commercial packaging of Simulis® Thermodynamics contains a Microsoft® Excel add-in and a MATLAB® toolbox and allows to use it in these environments. A complete API can also be provided and can be programmed easily by using languages such as Visual Basic, C++, Delphi, FORTRAN,…
To illustrate this "integrability" capability, we have chosen an example using the MATLAB® toolbox of Simulis® Thermodynamics (Fig. 4) where a CAPE-OPEN property package is retained to perform vapor heat capacity calculations.
Fig. 4 : example of MATLAB® code
The successive steps we can find in this example are the following:
1- Creation of a thermodynamic calculator object used to perform calculations.
2- Edition of its different unit systems (input and output) with a standard dialog (Fig. 5) supplied by the Simulis® framework. In fact, all features of Simulis® Conversions are included in Simulis® Thermodynamics.
Fig. 5 : Unit system edition dialog
3- Edition of the thermodynamic calculator and selection of the CAPE-OPEN property package (Fig. 6 to Fig. 8). A thermodynamic calculator in Simulis® Thermodynamics can be described either by selecting a CAPE-OPEN property package or, in native, by importing compounds from different data sources and choosing a thermodynamic model and its related binaries.
Fig. 6 : Thermodynamic calculator edition
Fig. 7 : Property Package selection
Fig. 8 : Property Package edition
4- Input data affectation: range of temperatures, pressure, composition, …
5- Vapor heat capacity calculations.
6- Plot of the results (Fig. 9).
Fig. 9 : Plot of the results
7- Freeing of the thermodynamic calculator.
Over 400 functions of the Simulis® Thermodynamics toolbox allow the programmer to access pure compound properties, thermodynamic models, binaries, CAPE-OPEN property packages and to calculate all available properties and phase equilibria.
Component based simulation environments open new horizons to study processes. They allow process engineers, by a judicious assembly of ready to use software components, to improve the quality of their studies while reducing associated development times. Thanks to the CAPE-OPEN standard, components interchangeability becomes possible. This flexibility makes it possible to select the software component considered to be most relevant for a given case. Thus, the component approach incontestably brings gains in productivity to the users as well as to the developers of these systems.
Simulis is a registered trademark of ProSim SA.
MATLAB is a registered trademark of The MathWorks, Inc.
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