Computer Program Update for Assessing Chemical Thermodynamics and Energy Release – September 14, 2020 – B. Keith Harrison and M. Dan Detman – Life Science News Articles

1. How many years has this new version of CETAH been in preparation?
It has been four years since the last release of CHETAH.
Version 10.0 was released in 2016, with the main feature being changed from a CD product to a download to meet the needs of secure labs and to upgrade to a newer operating system. There were three service packs with various updates, inclusion of SMILES and minor bug fixes
Buyers are strongly recommended to upgrade with the cumulative service packs included. Versions 9.0 and 10.0 will no longer be supported.
2. What are the notable new additions to CETAH 11.0?
a. Inclusion of NASA Lewis chemical equilibrium calculations in a user-friendly way using CETAH functionality.
New in CETAH 11.0 is the ability to calculate chemical equilibrium. This is accomplished using NASA’s thermodynamically rigorous Lewis CEA program which has been incorporated into CETAH. The NASA CEA program was first developed for the space program. This same technology is now assigned to a different use. Chemical equilibrium can be calculated for a number of different scenarios which are useful for assessing chemical reactive hazards. CETAH also enables its extensive chemical databases and use of the Benson Group method to enable the assessment of a much larger number of possible reactive chemical hazards using this new functionality.
CETAH can calculate the chemical equilibrium of a specified set of reactants under a specified set of conditions. NASA’s Lewis Program logic has been included in CETAH but allows for a much simpler interface and allows input reagents to be sourced from the large CETAH databases of chemicals (over 1700) while allowing the use of the Benson Group contribution method for describing chemicals not in databases. There is also a provision for the user to enter their own compounds into a special user database within CETAH.
CETAH allows three types of chemical equilibrium calculations:
1. Specified final temperature and pressure at chemical equilibrium. This option is particularly useful for finding the composition of the final product at equilibrium and the energy released to reach the final conditions.
2. Final pressure and enthalpy specified. This option is particularly useful for evaluating the final temperature and composition of the final product at equilibrium for an adiabatic reaction.
3. Internal energy and volume specified. This option is particularly useful for evaluating the final pressure and composition of the final product at equilibrium for a constant volume reaction.
b. Ability to save and restore recorded sessions from CETAH for reuse later or with a future version of CETAH.
vs. Ability to save user-defined chemical groups and their properties and transfer these groups to later versions of CETAH.
D. What essential information is in this edition of the book that cannot be found elsewhere? This edition of CETAH allows the user to assess potential reactive hazards by a number of methods that are not readily available elsewhere. This will help professionals involved in preventing such dangerous situations.
3. How does this manual help an engineer (or other profession) do their job better?
This software is a valuable tool to enable rigorous and sophisticated assessment of potential reactive and flammable hazards. The CHETAH results can then lead to an experimental program that would allow for careful hazard assessment under the conditions envisioned by the user.
It should be noted that CHETAH is one element of a chemical safety program. He can quickly assess a situation. However, CHETAH does not replace experimental laboratory safety programs. CHETAH is a valuable tool to guide experimental investigations.
4. What type of person would benefit from CETAH?
Professions that would use CETAH heavily: chemical engineers, chemists, safety engineers and those involved in fire prevention. Also, users would include academic settings such as academic chemistry and chemical engineering that have laboratory operations for teaching or research.
5. What are typical applications?
A center for the production or research of industrial chemicals which must assess the potential risks of chemical reactions or the risks of flammability.
A pharmaceutical company synthesizing new chemicals and/or pharmaceuticals as part of a research program would assess potential reactive hazards before making or attempting a synthesis reaction to make a new chemical or pharmaceutical.
Companies that specialize in the industry providing reactive and flammability assessments often use CETAH to help customers ensure safe operations.
Often, professionals in chemistry-related professions need to quantify the thermal effects of proposed reactions. This is important for preventing hazards, but also for routine reactor design. CETAH can provide valuable information for these purposes.
6. Explain why/how/if this program would be a valuable resource in academia?
CETAH has been used in university programs in chemistry, chemical engineering, environmental engineering/sciences and life sciences involved in teaching and research. It is useful in instruction regarding the energetic consequences of reactions, an assessment of product distribution for reactions reaching chemical equilibrium, and in safety education involving chemicals. It is also useful for instruction regarding flammability parameters such as lower flammability limit of mixtures and minimum ignition energy.
Academic research labs have the same safety concerns as industrial labs and as such seek to avoid accidents. CHETAH can be a valuable tool to help prevent accidents involving chemical reactions and also to help prevent accidents related to flammability.
7. What type of technical support is offered to users?
A user manual of approximately 200 pages is provided with the program. A PowerPoint tutorial on how to use the program is also provided. An abundant literature of scientific articles concerning CETAH is available in the open literature. A list of relevant articles is provided with the program. Software support is provided by ASTM and the program authors. Consultants are available to assist customers in their use of the program and to teach on the subject by WebEx or in person.
8. Are there publications that explain the use and experiences of using the CETAH feature?
Yes, on the website we have a tab called References. You’ll find nearly 200 articles, books, and book chapters on strategy, reactions, security, and more. The reference list is also available in the user manual. There is an extensive literature on the use of CETAH spanning approximately 50 years.
9. Is there an easy way to get familiar with using CETAH?
On the website there is a tutorial page with an abbreviated version that allows you to use the feature with a limited number of chemicals. There is a comprehensive PowerPoint presentation that covers all major features of CETAH for users to review before purchasing.
In addition to point a above, a long time and experienced user of the program, David Frurip, President of Frurip Consultancy, has lectured on the use of CETAH around the world. It does this through one- or two-day courses at the user’s site. However, it also offers these courses in abbreviated form through the use of WebEx.
Dave Frurip prepared the “how to” videos found on the intro page with full explanation and walkthrough of how to use the features. There are 4 videos:
• Introduction: a brief overview showing a heat of reaction demo
• Evaluation of the energy release (ERE) Explosive potential of a species or a chemical mixture
• Flammability calculations
• Analysis of chemical equilibria using the NASA-Lewis code

Gordon K. Morehouse