SupPhreeqc: A program for generating customized Phreeqc thermodynamic datasets from Supcrtbl and extending calculations to elevated pressures and temperatures

摘要

SUPCRT and PHREEQC are two software packages widely used for thermodynamic calculations and geochemical modeling of gas-water-mineral reactions, respectively. The versatility and easy-to-use functions of PHREEQC have earned its popularity, but the software is limited by the default thermodynamic datasets it is distributed with, which has limited PHREEQC applications to mostly at ambient temperature. To expand the applicability of PHREEQC to wider temperature and pressure conditions, this study developed the software utility SUPPHREEQC that extracts thermodynamic data from SUPCRTBL and translates them into PHREEQC-readable formats. By linking SUPCRTBL and PHREEQC, this study helps harness high-quality thermodynamic data for minerals and a large number of inorganic and organic aqueous species with the Helgeson-Kirkham-Flowers equation of state parameters for speciation and solubility modeling at elevated T-P.SUPPHREEQC can generate both formats of PHREEQC datasets, namely, phreeqc.dat and Ilnl.dat. These two formats differ in activity coefficient and gas-mixing models, as well as pressure corrections for log K. As examples, three datasets were made from SUPPHREEQC: diagenesis.dat (0.01-200 degrees C and up to 1000 bar), geothermal.dat (0.01-300 degrees C at P sAT ), and bl.dat at 0.5, 1, 2, and 5 kb 1000 degrees C. The diagenesis.dat and geochermal.dat datasets have also incorporated the library of callable BASIC scripts for rate equations and kinetic parameters for 53 minerals. These databases can be downloaded or run together with PHREEQC online at https://models.earth.indiana.edu.