Form Approved
REPORT DOCUMENTATION PAGE
OMB No. 0704-0188
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1. AGENCY USE ONLY (Leave blank)
2. REPORT DATE
3. REPORT TYPE AND DATES COVERED
October 1997
4. TITLE AND SUBTITLE
5. FUNDING NUMBERS
FREZCHEM2: A Chemical Thermodynamic Model for
Electrolyte Solutions at Subzero Temperatures
6. AUTHORS
Mikhail V. Mironenko, Steven A. Grant, Giles M. Marion, and Ronald E. Farren
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)
8. PERFORMING ORGANIZATION
REPORT NUMBER
U.S. Army Cold Regions Research and Engineering Laboratory
72 Lyme Road
Hanover, New Hampshire 03755-1290
CRREL Report 97-5
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)
10. SPONSORING/MONITORING
Office of the Chief of Engineers
U.S. Army Research, Development,
AGENCY REPORT NUMBER
Washington, D.C. 20314-1000
and Standardization Group (UK)
223 Old Marylebone Road
London NW1 5TH, United Kingdom
For conversion of SI units to non-SI units of measurement consult Standard Practice for Use of the
11. SUPPLEMENTARY NOTES
International System of Units (SI), ASTM Standard E380-93, published by the American Society for Testing and Materials,
1916 Race St., Philadelphia, Pa. 19103.
12a. DISTRIBUTION/AVAILABILITY STATEMENT
12b. DISTRIBUTION CODE
Approved for public release; distribution is unlimited.
Available from NTIS, Springfield, Virginia 22161.
13. ABSTRACT (Maximum 200 words)
This report documents a Fortran version of a chemical thermodynamic model for aqueous electrolyte solutions
at subzero temperatures, FREZCHEM2, which is a further development of the FREZCHEM model. The model
uses thermodynamic data of SpencerMllerWeare that permit the calculation of chemical equilibria in the
NaKCaMgClSO4H2O system between 60 and 25C at atmospheric pressure. It applies the Gibbs en-
ergy minimization method for chemical equilibrium computation combined with Pitzer equations for activity
coefficients and water activity calculation. The model includes both the freezing (melting) reaction pathway at
fixed water amount and the evaporation (dilution) pathway at fixed temperature. The FREZCHEM2 model can
be extended with respect to independent components, electrolyte species, and solids, and if corresponding
thermodynamic data are available, the model may be used to compute chemical equilibria in any systems that
include aqueous-solution and/or one-component solid phases.
14. SUBJECT TERMS
15. NUMBER OF PAGES
Aqueous solutions
Computer model
Freezing
48
Chemical thermodynamics
16. PRICE CODE
17. SECURITY CLASSIFICATION
18. SECURITY CLASSIFICATION
19. SECURITY CLASSIFICATION
20. LIMITATION OF ABSTRACT
OF REPORT
OF THIS PAGE
OF ABSTRACT
UNCLASSIFIED
UNCLASSIFIED
UNCLASSIFIED
UL
Standard Form 298 (Rev. 2-89)
NSN 7540-01-280-5500
Prescribed by ANSI Std. Z39-18
298-102
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