Data Set for Seawater and Brine

[MJF]

I wanted to know if you could recommend an appropriate data set for modeling seawater and/or brine systems. I am using the thermo.dat set right now and, looking at the file, it appears to support debye-huckel and b-dot activity calculations. I know that the ionic strength of seawater is way beyond the range of debye-huckel, but I'm not sure how long b-dot holds up. I was considering using thermo_pitzer.dat set, since I think the virial equations hold at much higher ionic strengths, but CO2/HCO3-/CO3-- is not included in the basis set, and carbonate minerals do not appear either. Thanks for any help!

[Tom Meuzelaar]

I wanted to know if you could recommend an appropriate data set for modeling seawater and/or brine systems. I am using the thermo.dat set right now and, looking at the file, it appears to support debye-huckel and b-dot activity calculations. I know that the ionic strength of seawater is way beyond the range of debye-huckel, but I'm not sure how long b-dot holds up. I was considering using thermo_pitzer.dat set, since I think the virial equations hold at much higher ionic strengths, but CO2/HCO3-/CO3-- is not included in the basis set, and carbonate minerals do not appear either. Thanks for any help!

 

Hello:

 

thermo_pitzer.dat is an outdated database that is included with GWB only for compatibility with early GWB releases.

 

I recommend that you use the Harvey-Moller-Weare compilation, thermo_hmw.dat, which treats solutions in the Na-K-Mg-Ca-H-Cl-SO4-OH-HCO3-CO3-CO2-H2O system at 25C.

 

You might also take a look at thermo_phrqpitz.dat, an expanded version of the H-M-W database, as implemented in the PHRQPITZ geochemical model, which has some provision for working at temperatures greater than 25C.

 

I hope that helps,

 

Tom Meuzelaar

RockWare, Inc.