Numerous software packages are available to calculate the thermodynamic properties and phase equilibria. They differ in thermodynamic models available, their databases, their interfaces, their access...

We recommend that those who are not familiar with these concepts first read the page on the methodology of calculating the thermodynamic properties and phase equilibria of pure substances and mixtures.

We present below four generic software packages.

We also suggest you consult the excellent on line training module on the properties of fluid mixtures prepared by our colleague J. Schwartzentruber and colleagues at the Ecole des Mines d' Albi, which also includes a special section devoted to the study of distillation.

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ProPhy Plus is a software for calculating thermodynamic properties and phase equilibria developed and distributed by ProSim. Several databases of properties of pure substances are available: the standard base (more than 1600 components) , DIPPR ( Design Institute for Physical Properties Data) base, and the users can create and manage their own private databases.

A thermodynamic wizard helps the user to find the right model for the studied system. Many thermodynamic models are available to cover a wide range of applications:

• models based on the use of an equation of state applicable to the entire fluid domain, such as Soave-Redlich-Kwong, Peng Robinson or Lee-Kesler Plöcker including conventional or complex mixing rules (MHV1, MHV2, …). These models are typically used in the refining, petrochemical and gas processing fields.

• models, widely used in chemical industry, based on the calculation of activity coefficients, such as WILSON, NRTL, UNIQUAC, UNIFAC, to account for non- ideality of the liquid phase.

• specific models are also available especially for electrolyte solutions.

The calculations of thermodynamic properties (density , enthalpy, entropy...) and equilibria between liquid-liquid, liquid-vapor and liquid - liquid-vapor phases ( bubble and dew points, isothermal, adiabatic, isentropic flashes...) of the pure substances and mixtures can be made for a system state, for example defined by its temperature, pressure and composition, or at intervals of variation of the state variables.

As an illustration, the figure below shows the plot by ProPhy Plus of bubble and dew curves of a mixture having an azeotrope.

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BibPhy Add-In ™ is a macro for Microsoft Excel ™ for performing calculations of thermodynamic properties and phase equilibria.

features described above are available in an Excel spreadsheet for easy use of additional functions. The figure below illustrates the insertion of BibPhy Add-In in a sheet of Excel.

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DiagSim is a software (Jean-Noel.Jaubert@ensic.inpl-nancy.fr ) that can predict all the properties of a pure substance and all phase diagrams from a cubic equation of state with volume adjustment (Peng-Robinson, Redlich-Kwong-Soave, optimal equation of Schmidt et Wenzel), ensuring a good accuracy of vapor-liquid equilibria and reliable calculation of volume properties.

DiagSim comes with a database including for more than 800 common compounds (saturated and unsaturated hydrocarbons, halogenated compounds, oxygen, inorganic...) critical parameters, acentric factor and the isobaric heat capacity of the ideal gas, to solve the equation of state.

Here is the (h, log P ) ammonia chart plotted by DiagSim.

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TEP ThermoSoft is a software package developed by the Laboratory of Thermodynamics and Equilibrium Phases (TEP) from Mines ParisTech.

As well as in PE 2000, many models are used to calculate the thermodynamic properties of equilibrium phases of a pure substance or a mixture. These models are based on parameters derived from either the internal database or an adjustment by the user based on experimental data with the ability to view deviation graphs. A graphical tool was developed specifically for visual, easy comparison of datasets, this for their selection for any adjustment of parameters.

The diversity of models proposed associated with several rules for mixtures, in a phi -phi approach, allows for the calculation of PT envelopes (bubble and dew points. See figure below), and various types of equilibria (liquid vapor, liquid-liquid, liquid - liquid-vapor... ) possibly for azeotropes and several critical points.

The behavior of a system can be approached from the perspective of different thermodynamic properties. Therefore, TEP ThermoSoft includes the calculation of excess properties (enthalpy, entropy, volume, heat capacity) and energy properties (enthalpy, free energy, entropy...). Indeed , the study of GE and HE (see figure below) is very useful for analyzing the consistency of the experimental data.

The 2004 version of this software includes the gamma phi calculation approach and allows a user to add his own thermodynamic models. An "education" version is available for the academic community.

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TEP Lib is the library for calculating thermodynamic properties of the Laboratory of Thermodynamics of phase equilibria of the Ecole des Mines de Paris (Mines ParisTech).

Essentially, this is the Java translation by R. Gicquel and B. Liu of TEP Thermosoft libraries initially developed in Delphi. We express our gratitude to EDF, which funded part of this translation, for allowing us to distribute theses libraries.

Coupled to Thermoptim 2.5, it can calculate the properties of mixtures of real fluids, which the software cannot do itself.

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Finally let us indicate, although they are outside the scope of this page, very powerful but expensive general software that can design and analyze the operation of chemical processes. This process simulators have steady major objectives:

• solve the equations of mass and energy balances for all devices of the process;

• calculate the characteristics (flow rate, composition, temperature, pressure, physical properties) for all fluids circulating within and between devices;

• provide the elements needed for equipment design.

Among the best known are:

• ProsimPlus

• Aspen Plus

• Pro II

Finally, DDBSP is a software package distributed by the company Dortmund Data Bank Software and Separation Technology, which provides the thermodynamics and transport properties of pure components and mixtures for the design and development of processes, as well as special programs for data correlation, process evaluation and synthesis. Almost all existing world data and over 3000 data of mixtures containing ionic liquids are available.