ChemApp "light" README
Notes on the usage of ChemApp light with Aspen Plus (V11.1 SP1 and up)®

These release notes contain information on

  1. how to install ChemApp,
  2. how to use ChemApp light with Aspen Plus (V11.1 SP1 and up),
  3. notes for users of ChemSage V3.x,
  4. how to sign up for e-mail support,
  5. how to report a problem or bug,
  6. how to join our GTT-News newsletter mailing list,
  7. and how to contact us.

Please read this file and the file f-notes.txt and license.txt before using ChemApp, and feel free to contact us any time if you need any further information.

You should also take a look at the ChemApp FAQ, which is at FAQ . It answers a lot of standard questions about ChemApp and ChemApp light and should especially be consulted before contacting our support.

Another must read for ChemApp developers is the chapter ChemApp best practises in the ChemApp Programmer's Manual (added for Edition 3.6). Before you contact our support with specific questions relating to your code, please make sure your code implements the ChemApp best practises.

  1. To install your version of ChemApp light, simply run the setup program. In case you downloaded ChemApp light from our web site, the setup program might be zipped. In this case, unzip the ZIP file to a temporary directory and execute the resulting setup program.

    A corresponding un-installation program will also be set up, in case you want to remove ChemApp light again later.

    The installation program will put the ChemApp DLL(s) not only in the user-defined directory you specify during installation, but also into the Windows system directory, in order to make it available to your applications during compile- and run-time.

  2. This version of ChemApp is for use with Aspen Plus (V11.1 SP1 and up) and is a 32 bit DLL for use under Windows 95, Windows 98, Windows ME, Windows NT, Windows 2000, and Windows XP® on Intel® x86 and compatible processors.

    This distribution of ChemApp for Aspen Plus (V11.1 SP1 and up) contains one ChemApp DLL (chemapp.dll), which is the "light" version of ChemApp for Aspen Plus (V11.1 SP1 and up). The installation program copies this file both to your Windows' system directory, as well as to the installation directory.

    To be able to use ChemApp light with Aspen Plus (V11.1 SP1 and up), the following steps are necessary:

    • Aspen Plus needs to be installed on the same computer. The minimum version of Aspen Plus required is V11.1 SP1, earlier versions are NOT supported.

    • From the Aspen Tech support web site at, download the most recent cumulative hotfix for the Aspen Plus/FactSage/ChemApp interface. Carefully follow the installation instructions included with the hotfix.

    • On the Aspen Tech support web site at, look for the TechTip on the Aspen Plus/FactSage/ChemApp interface that includes pbznlite.bkp. This is a short flowsheet example that works with ChemApp light.

    • Start the Aspen Plus GUI with a blank simulation. Open the help system ("Help|HelpTopics") and read the topics under Using FACT and ChemApp with Aspen Plus.

    • In particular, consult the topic Configuring Aspen Plus to Use the Aspen/FACT/ChemApp interface. Carefully follow the instructions in the sections Adding the ChemApp model to the Model Library, Testing the Aspen/FACT/ChemApp interface, and optionally Troubleshooting simulations with the Aspen/FACT/ChemApp interface.

    • You should now be able to load pbznlite.bkp and run the simulation.

  3. Note for users of ChemSage V3.x: If you are still using ChemSage V3.x and would like to continue using your existing thermochemical data-files with ChemApp, you will need to convert them to the ChemSage 4.x/ChemApp format with a program called ChemFile. This program can be obtained from GTT-Technologies upon request, in case it is not included in this distribution of ChemApp. Note that users of ChemSage V4.x, FactSage, and earlier versions of ChemApp do not need to convert their data-files.

  4. To receive limited e-mail support for ChemApp light, please register your copy of ChemApp light. Registration is free and can be done in any of the following ways:

    • Use the online registration form on our web site: register.

    • Fill out the form in the file register.txt that comes with this distribution using an ASCII editor. Send it by e-mail to

    • Print out the file register.txt, fill it out and fax it to GTT-Technologies: +49-2407-59661

  5. We have installed a bug tracking system for ChemApp that allows us to handle bug and problem reports in a quick and flexible fashion. If you have a programming problem with ChemApp that you suspect might be a bug, please use the Bug Report Form at

    Bug Report Form

    There is also a link to this page from the ChemApp web page.

    If you don't have access to the World Wide Web, you can submit your bug reports by e-mail to We prefer the submission of bug reports via the web page though, since filling in the Bug Report Form makes sure we have important information like the ChemApp version number etc. we need to reproduce your problem already.

    If you have any other general or support questions about ChemApp, there is always our support e-mail address:

  • Join our GTT-News newsletter mailing list: This newsletter is distributed mainly electronically by e-mail, and also posted to our web site ( It contains announcements of new versions of our various software programs, information on new features and enhancements, ongoing projects, new thermochemical data, additions to our web site, seminars, publications, and various other topics. To join, check the GTT-News section on our web site for instructions, or send an e-mail to with the line
    in the mail body.


  1. An up-to-date source of information on ChemApp, its applications, and related topics is "GTT's Technical Thermochemistry Web Page":

    We would like to include a brief description of your projects involving ChemApp on this World Wide Web page too. Please contact Dr. Stephan Petersen ( for details.



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