Tridiagonal Solutions > Tridiagonal Partners FactSage

FactSage Family of Products and Services

FactSageTM is a thermochemical software and database package developed jointly between Thermfact/CRCT (Montreal, Canada) and GTT-Technologies (Aachen, Germany)

Both GTT-Technologies and Thermfact/CRCT offer a suite of software products that can access the FactSage databases (*.cst files) or enhance the FactSage environment. In addition other software developers have programmed interfaces to access the FactSage data and software within their own packages. The following is a brief summary of these products.

  • FactSage-Teach – a thermochemical teaching package based on FactSage
  • ChemApp – the thermochemistry library for your software
  • ChemSheet – the spreadsheet tool for process simulation
  • SimuSage – ChemApp-based set of Delphi components for process simulation
  • OLI Systems – FactSage Interface: the link to the OLI Aqueous Databanks
  • METSIM – FactSage Link
  • Database Development and other Consulting Services

Note: – FactSage-Teach is included in the FactSage 7.1 package.

FactSage-Teach is a thermochemical teaching package based on the ITDS FactSage. It comprises a suite of application databases and a comprehensive workbook, and needs as a prerequisite the standard version of FactSage. The package introduces the student, or any interested practicing thermochemist, to the practical use of thermochemistry for solving everyday problems in industry, research and environmental sciences. Through gaining a knowledge of how computational thermochemistry works, a student is more inclined to learn the theory behind an otherwise rather dry subject matter. The workbook comprises three sections covering (a) the background of the theory relating to the practical application of thermo-chemistry; (b) the assignments, given with questions and answers; and (c) a quick reference guide to the software. The Teach package follows an interactive concept and permits a user to check out ‘what happens if’ by changing input parameters, and detecting the effects in the result tables or diagram output.

The Teach package is the result of a series of seminars and courses on Computational Thermochemistry held by K. Hack during the last 15 years. Many suggestions of the seminar participants have been incorporated in both the text and the assignments. The Teach package helps everybody who uses it to understand that Computational Thermochemistry is a tool for application in day-to-day work but also a method for gaining insight into a sometimes relatively sobering theoretical subject.

The package assists the user in practicing the three step process which is always involved in the application of Computational Thermochemistry:

  1. 1. Analysis of the practical problem in terms of input for a calculation,
  2. 2. Selection of the appropriate program module (and database(s)) and execution of the calculation,
  3. 3. Interpretation of the results in relation to the initial practical problem.

In order to execute this three step process properly the handbook links the practical assignments (given in section II) on the one hand with an outline of the theoretical background of Computational Thermochemistry (section I) and on the other with information on the actual use of the various modules of FactSage (section III, together with the slide show files of FactSage). Appropriate cross-references to sections I and III are given with each assignment in section II.

Below is given in tabular form an overview of the various applications used in the practical assignments:

Table XX – Practical Assignments in the Teach Package
1. Systems with pure substances
1.   Data fore pure substances in SER-form and as relative G-functions
2.   Aluminothermic welding of rails
3.   Isothermal standard and non-standard reactions between Cu and Cu2O
4.   Production of ultra-pure silicon by CVD
5.   Gas equilibria, substance properties, combustion calculations
6.   Application of the phase rule to the system Ca-C-O

2. Systems with solution phases
1.   Data for solution phases / calculation of thermodynamic properties
2.   Thermochemistry of an alloy system, Co-Cr-Fe
3.   Thermochemistry of an alloy system, using a private database: the Cr-W system

3. Phase Diagrams
1.   From the Gibbs energies to the phase diagram:
the binary system Pb-Sn
2.   Zero-phase-fraction lines, learning how the work in given phase diagrams
3.   Phase diagram calculations
I:   CaO-MgO (treating a miscibility gap in the solid state)
II:  Fe-Co-Cr (the ZPF lines are traced in an isotherm)
III: Al-Si-Zn (the ZPF lines are traced in an isopleth, constant amount of Si)
IV: Fe-Cr-O2 (log P(O2) vs x(Cr) at constant T and P)
V: Fe-C-Cr-W (an isothermal, isoplethal (constant C amount) and isobaric diagram)
VI: CaO-MgO-ZrO2 (the liquidus surface using macros and the O-option)

4. Aqueous solutions
1.   Precipitation and co-precipitation in aqueous solutions
2.   A leaching process for ZnO
3.   A phase diagram for Cu-H2O-HCl-NaOH-H2 aqueous applications with practical axes variables

5. Process thermochemistry
1.   Aluminothermic process with solution phase formation
2.   An argon vacuum refinement process of a metallic melt
3.   Desulphurisation of Cu2S in flowing air
4.   Silicon arc furnace simulation (using a pre-fabricated SimuSage model)

Further information on the Teach package is available on request directly  from GTT (

ChemApp – the thermochemistry library for your software

ChemApp provides the powerful calculation capabilities of the ChemSage Gibbs energy minimiser (the same one that powers the FactSage modules Equilib, Phase Diagram and OptiSage) in the form of a programmer’s library. It consists of a rich set of subroutines which provides all the necessary tools for the calculation of complex multicomponent, multiphase chemical equilibria and the determination of the associated thermodynamic properties of the system, its phases, and their constituents.

Potential applications for the use of ChemApp are almost limitless and can cover an extremely diverse range of applications. Two distinctly different groups of applications of ChemApp are possible:

  • using it for the development of application-specific programs; for example, for handling repetitive complex equilibrium calculations, for analysis, and for process control in well-defined technological areas,
  • linking it to third-party process simulation packages for modelling new or optimising existing processes; for example, commercial CFD programs such as Fluent®, CFX®, general simulation programs, including Aspen Plus®, PRO II®and also a company’s own process simulation program.

ChemApp is available for a wide variety of programming languages (e.g. Fortran, C, C++, Visual Basic®, Delphi®) and hardware platforms/operating systems (e.g. Windows, Linux, Unix).

ChemApp reads ChemSage (.dat and .cst) thermochemical data files (note, .cst files can be generated by the FactSage Equilib module).

For detailed information on ChemApp features, ChemApp “light” versions available for download, publications and ongoing projects together with an online version of the programmer’s manual, with complete references to all ChemApp subroutines and dozens of code examples in both FORTRAN and C, plus several worked examples, consult the ChemApp section on GTT-Technologies’ web site.

ChemSheet – the spreadsheet tool for process simulation

ChemSheet combines the flexibility and practicality of spreadsheet applications with rigorous, multi-phase thermodynamic calculations. It was developed in a co-operation between GTT-Technologies and VTT Chemical Technologies in Espoo, Finland.

ChemSheet is an add-in for Microsoft’s EXCEL™. It provides a link between ChemApp, the programmer’s library for thermochemistry (using the same ChemSage Gibbs energy minimiser as in the FactSage modules Equilib, Phase Diagram and OptiSage) and an EXCEL spreadsheet. Each application is defined as an independent worksheet in which the entire simulation can be done. Interaction with ChemSheet is done through easy to use dialog boxes which provide the user with a tool to link values of variables with cells in the spreadsheet. The graphical capabilities of EXCEL are available for the visualisation of the results.

One of the major strongholds of ChemSheet is its applicability to systems with kinetic inhibitions such as the production of TiO2 reaction of TiCl4 with O2. Although the equilibrium of this reaction is on the TiO2 side it is kinetically retarded. The effect of this constraint on the global equilibrium with all other chemical species of the system being fully equilibrated has been successfully modelled using ChemSheet.

ChemSheet requires ChemSage (.dat or .cst) thermochemical datafiles. (.cst files can be generated by the FactSage Equilib module.) For the inclusion of the data that permit the kinetic calculations referred to above it is necessary to modify the standard .dat file. A software called ChemSage File Administration Program is available for that purpose.

A free demo version of ChemSheet, called ChemSheet-light, is available. For more details on ChemSheet including animations of ChemSheet applications and a download of the demo version click on ChemSheet Information.

SimuSage – the component library for rapid process modelling


is a ChemApp-based set of Delphi components for process simulation (flowsheeting) tasks. SimuSage has originally been developed by SMS Demag as an internal tool. Subsequent development work at GTT-Technologies has turned it into a commercial product.

With SimuSage you can develop a model for a process using a set of “unit operations”. These are comprised of stream splitters, mixers, equilibrum reactors, iterators and others. Build your entire model using the unit operations in basic configurations such as by-passes or split equilibria (to include kinetic inhibitions into your process), or use recycle streams with (or without) internal equilibrium in order to handle output from one stage as input to a previous stage.

Simple process simulations can be set up using visual programming alone, no coding is required. When the demands in the complexity of your simulations increase, Delphi with its technologically advanced programming concepts and tools offers you everything necessary to produce highly customized applications.

The highlights of SimuSage are:

  • Rapid process modelling: assemble process models involving complex thermochemistry in a minimum amount of time
  • Modern development environment: use state-of-the-art Borland Delphi visual programming tools
  • Fast, custom-made programs: create standalone executables for internal or external distribution
  • Limitless extensibility and customization: all Delphi features are available to extend SimuSage and customize your own applications

ChemApp reads ChemSage (.dat and .cst) thermochemical data files (note, .cst files can be generated by the FactSage Equilib module).

For more information, consult the SimuSage section on GTT-Technologies’ web site.

FactSage – OLI Systems Interface – the link to the OLI Aqueous Databanks

The FactSage – OLI Systems link is no longer supported.

METSIM – FactSage Link

The FactSage – METSIM link is no longer supported.

Database Development and other Consulting Services

We offer extensive database development and other consulting services. For more information please contact us at

Pravin, one of the five members of Board of Directors in Tridiagonal Solutions has proven his expertise in creating, positioning and managing high growth companies. Mr. Jain has completed his Bachelors in Computer Engineering from University of Mumbai and Masters in Computer System Engineering from Northeastern University, Boston. He has also completed the Executive Program for Growing Companies at Stanford University Graduate School of Business. He has over 17 years of experience in Technology Entrepreneurship, Business Development and Delivery of Customer Centric Solutions. Pravin’s experience includes acquiring as well as divesting companies. Pravin lived and worked for 14 years in the US, and shifted back to India in the summer of 2006. He has driven, and been accountable for Sales, Marketing, Technology, Delivery and Strategy functions at his previous ventures. Pravin’s previous company grew by over 40x in 6 years and was subsequently divested to Wipro.

Ashish heads the software development activities at Tridiagonal Solutions. He has Post graduate degree in Fluid Mechanics and Thermal Sciences from IIT, Kanpur. Ashish is also a founder member of Tridiagonal and his interests include Computational Fluid Dynamics, Turbulence Modeling, Technical Training and Mentoring along with Open Source Software Development. Before founding Tridiagonal, Ashish worked with Fluent for seven years where he looked after product management responsibilities for Catia and FlowLab products.

Dr. Damodaran Vedapuri heads the North American Operations of Tridiagonal Solutions. He obtained his doctorate from Ohio University. Dr. Vedapuri has wide experience in Computational Fluid Dynamics, Flow Accelerated Corrosion and solving Multiphase Flow Problems of interest to the oil and gas industry. Before joining Tridiagonal, he was employed with SwRI, a premier research lab in the US and at Fluent Inc.

Dr. Damodaran Vedapuri heads the North American Operations of Tridiagonal Solutions. He obtained his doctorate from Ohio University. Dr. Vedapuri has wide experience in Computational Fluid Dynamics, Flow Accelerated Corrosion and solving Multiphase Flow Problems of interest to the oil and gas industry. Before joining Tridiagonal, he was employed with SwRI, a premier research lab in the US and at Fluent Inc.

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