Methodology and Standards
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HCh specifications
(HCh for Windows)
HD space requirements
2Mb for the initial installation.
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Operating systems
Windows 32 (9x, ME, NT, 2K, XP, Vista) operating systems;
Windows-emulating packages for the Macintosh computers.
Databases, chemical systems, phases and solutions
Databases
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Number of user-defined databases:
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Unlimited
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Database usage:
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One at a time
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Data sources for the default database
Miscellaneous sources; partially based on SUPCRT 92
Database Components and Capacity
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Stoichiometry units:
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Chemical elements
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105
<=150
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Standard (conventional)
User-defined
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Database components
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Database capacity
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Chemical compounds
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Equation of state
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Pure water
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Pure water
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Haar-Gallagher-Kell model (Kestin et al, 1984)
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Basic species
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1023
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- Simple ions
- Polyatomic ions
- Aqueous complexes
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The revised Helgeson-Kirkham-Flowers equations of state (MHKF) (Shock et al, 1992; Tanger and Helgeson, 1988)
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Complexes*1
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1023
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- Aqueous complexes
- Polyatomic ions
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The modified Ryzhenko-Bryzgalin model (Borisov and Shvarov, 1992) |
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Pure phases |
1023 |
- Minerals
- Ideal gases
- Non-aqueous liquids
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Conventional integration of heat-capacity equations*2 |
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Gases |
1023 |
Gases |
Conventional integration of heat-capacity equations*2 +
Peng-Robinson Stryjek-Vera equation of state (Stryjek and Vera, 1986) |
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Total |
4092 |
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Note:
*1 Optional definition according to the isocoulombic approach by
Gu et al. (1994)
*2
- Cp(t)=a+b*T+c*T -2+d*T -0.5+e*T
2+f*T 3+g*T 4+h*T -3+i*T
0.5+j*T -1
- Allowed number of phase transitions in minerals: 4
- Maximum number of the Cp(t)equations: 5
- No provisions for calculation of mineral compressibilities
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Limitations of chemical models |
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Maximum number of chemical elements allowed in models: |
30 |
Allowed model phases and solution models |
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Phases |
Maximum number of phases |
Solution model and calculation of activities |
Maximum number of components in the solution phase |
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Pure solids (minerals, liquids, and gases) |
255 |
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Solid solutions (ideal multi-site mixing) |
Unlimited |
Ideal:
- Molecular
- Mixing-on-sites (MOS,
4 sites allowed)
- Local charge balance (LCB)
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255
21
21 |
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Liquid non-aqueous solutions |
Unlimited |
- Ideal
- Non-random two-liquid (NRTL)
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255
7 |
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Gaseous mixture |
1 |
- Ideal
- Peng-Robinson Stryjek-Vera (PRSV)
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255
7 |
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Aqueous solution (including supercritical aqueous phase) |
1 |
Water: γ = 1 or according to the HKF model
(Helgeson et al., 1981); Charged species: extended versions of the Debye-Hückel equation
(Helgeson, 1969; Helgeson et al., 1981; Oelkers and Helgeson, 1990);
Neutral species: Setchénow equation (eg, Oelkers and Helgeson,
1990) |
255 |
Special Notes |
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Recommended T-P range for systems containing aqueous solution: |
0-1000°C, 1-5000 bar at water densities exceeding 0.35
g/cm3 (according to the MHKF model) |
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Allowed salinity range for systems containing aqueous solution: |
Limited by the applicability of the extended versions of the
Debye-Hückel equation; Computationally sensible results for I<10 M |
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Related factsheets
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Related links
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