PhreeqcUsers Discussion Forum

Beginners => PHREEQC basics => Topic started by: ACSchubert on March 06, 2019, 04:12:25 PM

Title: Determining differences between version 2 and version 3
Post by: ACSchubert on March 06, 2019, 04:12:25 PM
Dear all,

I am trying to map out differences between version 2 and version 3 of PhreeqC, to find out which parts of the code I have to change, when switching from version 2 to 3. Especially when it comes to units I am a bit lost.
1) for "Exchange" the manual states for both versions, that I have to enter the amount of exchange sites in mol. I think in version 2 it is mol/L water, correct? Does that change in version 3, eg. to mol/kg of solid matter?
2) The same question comes up for "Equilibrium_phases": Is it mol/L water or mol/kg solid in the different versions?
3) Are there more keywords, in which the reference of an amount changed? Anything you encountered when transferring the code from version 2 to 3?

Thank you in advance and best wishes from springlike Germany,
Agnes
Title: Re: Determining differences between version 2 and version 3
Post by: dlparkhurst on March 06, 2019, 05:07:07 PM
The units are the same between version 2 and 3; both use moles for definitions of number of exchange sites, surface sites, and equilibrium_phases. To use mol/kgw is problematic if the mass of water of the solution changes, and the volume of water may or may not be well defined, depending on the database, and, like kgw, mol/L has problems if the volume of water varies from 1 L.

I don't remember that there are any changes between version 2 and 3 regarding input, other than extensions of capabilities. I think the same input file and database file would give the same results regardless of version. The RATES equations were changed to use different input parameters related to surface area, although old RATES definitions would still work provided the KINETICS block was defined appropriately.
Title: Re: Determining differences between version 2 and version 3
Post by: ACSchubert on March 12, 2019, 10:19:46 PM
Dear Mr. Parkhurst,
thank you a lot for your response!
Best wishes,
Agnes Schubert