About ChemE Calcs

ChemE Calculator is a powerful tool with a simple interface for running VLE and steam table calculations on your iPhone or iPad, or for doing unit conversions. Ever been working a problem with your colleague, the path to real answers illuminated before you, when suddenly you need to do a quick dewpoint calc or check the heavies content in a vapor phase? How about working a startup and needed to know how much duty your steam turbine can achieve with a lower pressure source? Ever been in a meeting with the VP who's asking for sources of product loss and find yourself wishing you included the composition for the knockout drum bottoms stream in your slides?

ChemE Calcs was developed by a chemical engineer originally to do routine calculations without having to bother firing up the laptop and use a process simulator. The first release focused on multicomponent VLE calculations, but after receiving initial feedback the second version was developed with steam table calculations using equations based on the current industry standard. Once the steam tables were added, a unit converter was added to the next release, and Version 3.0 was released in January 29. The app continues to evolve, with new functionality in the works for the next release. Kitten pictures are also included, just because. Enjoy!

The app is very much a work of love, and feedback is encouraged to foster continuous improvement. There is a
Contact form on this site, accessible from the "Menu" icon at the upper right hand corner of the screen (three horizontal bars). Alternatively, you can access the contact form from any Information screen in the app via the link at the bottom of the page. For a quick tutorial on running a VLE calc, click the "Menu" icon and select "Tutorial."


This app has the following functionality:
  • Isothermal flash unit operation - Multicomponent vapor liquid equilibrium calculations using the Peng-Robinson equation of state.
  • Bubble pressure calculations (using the same equation of state)
  • Dew pressure
  • Bubble temperature
  • Dew temperature
  • Steam tables
    • Generalized tables - specify (p, T) to determine the phase plus thermodynamic properties such as specific volume, enthalpy, entropy, heat capacity, speed of sound, compressibility, etc.
    • Saturated vapor/liquid - specify p or T to determine thermodynamic properties of both the vapor and liquid phase
    • Wet steam - Specify several different property pairs to define a mixed phase (vapor + liquid) system, and determine the rest of the properties
    • Superheated vapor, Subcooled Liquid, Supercritical Fluid - Specify different property pairs to determine properties of a single phase system
  • Unit converter - 29 different types of unit sets are available. Types of units include energy, entropy, volumetric flowrate, thermal conductivity, mass concentration, power, force, etc.
  • Chemical database search - Search for compounds in the PubChem database hosted by the US National Institute of Health. Shows a structure for each hit, and selecting a hit pulls up additional information including structural formula, empirical formula, molecular weight, CAS number, IUPAC name, partition coefficient and PubChem compound ID.
  • Compound details include links to the NIST database that can lead to even more information posted on the NIST site, which can be viewed without leaving the app.
  • Instructions describing what each screen is for and how to use it - access a screen's instruction by pressing the "Info" icon at the top right corner of that screen.
  • Kitten pictures - Yes, it's true. Get your fix of cuteness. Why are they included? Just because.

Hopefully you will find ChemE Calcs a useful tool in your box - please feel free to send your questions or comments via the Contact form on this site. If the app ever crashes on you, please send me info about what led up to that ASAP. I take pride in my work, and want to ensure things work properly for everyone. Even if you just feel like saying hello, send me a note so I can hear how you use ChemE Calcs!