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Stability limits of water in Eh-pH diagram using thermo_minteq

Tom Meuzelaar

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[admin note: this post represents recovered forum content after a critical hard drive failure - it is not in it's original form]



Sep 26 2007, 07:34 AM

Hi Everyone

I am trying to plot a Eh-pH diagram using Act2 and the thermo_minteq

database. However the diagram did not show the stability limits of water

and when I try to find out from the Log it gave the statement "Reaction

for H2(g) is missing, can not plot water limit".

Also I tried to add a new thermo database (a hybrid one to reflect chemical species of interest) to the ones which came with the program but when I tried to

open the database in the programs, the programs did not recognize it.

I will be glad if anyone can help me fix this problems.





Hi Joseph:


If you uncheck the "Water limits" option under the Config-options menu, this error should go away. This archive thread has a little more information about using the Minteq database for Eh-pH diagrams in Act2.


Regarding your hybrid thermo database, it is hard to troubleshoot without being able to see the database. More often than not, the problems stem from a minor issue, such as being sure to increment the total Aqueous Species header number when you add an aqueous species to the database, or having formatted the entry in the correct fashion. If you haven't read the Thermo Datasets appendix in the back of the GWB Reference manual (p. 207 in the version 6 manuals), I strongly recommend that you do so.


Hope that helps,


Tom Meuzelaar

RockWare, Inc.

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