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Revisiting DIERS' Two-Phase Methodology for Reactive Systems

Posted by Hans K. Fauske, D.Sc. on 04.14.15

In connection with celebrating the 35th anniversary of the company, it seems appropriate to revisit the DIERS research project completed in 1985 under my leadership. As a follow-up in response to frequent suggestions by the industry that the DIERS methodology can be too complex and time-consuming, and overly conservative in many cases leading to impractical relief system designs, we have devoted time over the years to develop more "easy-to-use" adiabatic calorimetry and relief vent sizing equations demonstrating very good agreement with all available experimental data including vapor, gassy, and hybrid systems and plant experience (remember without data all you have is an opinion). At this time, I am very pleased to report that the frequent industry concerns have been properly addressed. 

As such, the "easy-to-use" methods provide alternatives to methods dependent upon sophisticated computer algorithms such as SAFIRE, and others, and can be properly viewed as the key practical component of the current DIERS vent sizing methods. It should also be noted, that the "easy-to-use" methods can serve well as an independent check on accuracy of the more complex algorithmic methods.

The "easy-to-use" methods provide:
  • Verified relief sizing equation(s) applicable to vapor, gassy and hybrid runaway reaction systems
  • Verified two-phase flow equations including flows through PSV
  • Accounting for flow regime variations such as churn turbulent, bubbly and viscous
  • No need for physical properties, which in many cases are not readily available
  • Illustrate the large advantages of setting the relief activation pressure as low as practical (less than MAWP), and
  • Elimination of oversizing which is essential in assuring stable PSV operation

To learn more about the "easy-to-use" DIERS adiabatic calorimetry vent sizing methods, join us at the forthcoming relief system design seminars.


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