The utility integrates with Aspen HYSYS and aids in the evaluation of CO2 freeze potential for natural gas processing plants. It predicts both vapor and liquid phase CO2 freezing temperatures for process streams, heat exchangers, expanders, and columns.


The utility uses a combination of equation of state (Peng-Robinson) and activity coefficient based (NRTL) models for its predictions. The models are tuned with a comprehensive set of critically reviewed experimental data. Its CO2 freeze prediction is believed to be the most accurate, publicly available for complex mixtures typical of the natural gas processing industry. And where other calculation methods fail mathematically and can report incorrect
freezing temperatures, we have developed solution methods that avoid these typical pitfalls. And, as discussed in our GPA paper CO2Freeze.pdf, we match up well with actual plant operating data.


The utility is a custom user operation extension and is very easy to install and use within HYSYS. It is similar in design to that of all of the standard simulation unit operations and may be used in any version of HYSYS version 3.1 or later. Simply pick a process stream (either single phase or two phase), a column, a heat exchanger, and so on and the utility will immediately calculate the appropriate CO2 freeze information.


» The ability, within a given process simulation, to rapidly and conveniently check numerous process streams and unit operations for areas where CO2 freezing may be of concern.This not only saves time, but also ensures that no problematic areas go unnoticed during the design phase of a project.

» Confidence in more reliable predictions may allow a plant operator to increase NGL recoveries by reducing its operating CO2 freeze margins.

Clients who have already licensed the utility: ConocoPhillips, Marathon Oil, Mustang Engineering, Black & Veatch, and others.

To request a WebexTM demonstration, please contact [email protected] and provide your full contact information.


** Please note that HYSYS version 3.1 or later is required.

The utility may be licensed for a nominal fee and has no annual maintenance agreements.

Aspen HYSYS is a registered trademark of Aspen Technologies, Inc., Cambridge, Massachusetts USA.