Gastherm Update for Gasworks and Solvgas

As of 2022 there is renewed interest in programs Gasworks and Solvgas, using Gastherm.dat as their thermodynamic data source. A significant issue is the absence of most digital records of the enthalpy, entropy, and heat capacity data that were used to compute the log K's for the gases. If logK's within Gastherm are to be modified (i.e. addition to or improvement upon) then records of enthalpy, entropy, and heat capacity are essential for each gas, mineral/solid, and liquid. Herein we document the construction of a new Gastherm database, and the data used for it. While the sources of data are well documented, all of it must be recompiled from scratch.

The 1990 version —

• Gastherm 1990 with some minor modifications. Add a text delimiter between derived gases and solids, and remove blank lines where in the past they were required for 16-bit operating systems wherever the preceding line exceeded 72 characters. A name change for one item only Al2O3 glass, from "Al2O3(g)" to "Al2O3-gl". Some revision of the text header. Gasworks and Solvgas modified to accommodate these changes. These will be the only changes to the programs until after completion of the Gastherm update, in a perfect world [May-2022].
• Demo files for Gasworks and Solvgas
  

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A summary of the procedure to update Gastherm —

• Find in the references the enthalpy, entropy, and heat capacity for each gas, or each mineral/solid or liquid, and add those to the Supcrt database.
• Use these programs-
  
• SupcrtRxnGT - creates Supcrt reaction files. Uses input files Gastherm.dat and one of two (incrementally updated) name index tables, to  [Nov-2022].
• Supcrt96 - computes logK's. Uses input files from SupcrtRxnGT, above [1996].
  
• Gastab - generates Gastherm-formatted records from Supcrt96 logK output. Uses input files Gastherm.dat, one of the the name index tables, and Supcrt96 output [Feb-2023].
• RegressGT - generates the last line of each Gastherm record, regression coefficients for interpolating logK's at intermediate temperatures using the equation logK(T,°K) = a + b T^-1 + c T + d T^-2 + e log(T) [Mar-2023].
  
• Insert the new data into Gastherm

More info —

• References
  
• Local
• janaf.nist.gov

• SupcrtRxnGT — Reads a previous version of Gastherm, name index tables to reconcile names between Gastherm and the Supcrt database, and writes a reaction file for Supcrt. Largely complete [Nov-2022].
• Input files:
     Gastherm.dat
     GTgases.tbl, index table of derived gas names, 5 items
     GTsolids.tbl, index table of mineral, solid, and liquid names, 4 items
• Output files:
     GTgases.rxn, Supcrt reaction file for gases, or in a separate run:
     GTsolids.rxn, Supcrt reaction file for solids and liquids
     MissingItems.dat, items that are missing from the index tables
• Accessory name index files. Species will be copied from "all" to "current" as they are added to the Supcrt database:
     GTgases.all.tbl, 585 items
     GTgases.current.tbl, 5 items
     GTsolids.all.tbl, 399 items
     GTsolids.current.tbl, 4 items

• Supcrt96 — Identical to a copy elsewhere on this site, but with data limited to those more relevant to the task at hand.
  • Input files:
       dpronshp.dat, thermodynamic data
       GT.con, temperature and pressure array
       GT*.rxn, reaction file
  • Output file:
       Name = *dealer'schoice*.*

• Gastab — Reads Supcrt96 output, the previous version of Gastherm used to generate the the Supcrt reaction file, and the aforementioned name index tables, and writes records properly formatted for Gastherm, but without regression coefficients.
  
  • Input files:
       Gastherm, the same version used to generate the Supcrt96 reaction file
       One of the two name index tables, the same as for SupcrtRxnGT
       Supcrt96 logK output (name = *dealer'schoice*.* from above)
  • Output file:
        Name = *adifferentchoice*.* (different from the input file name.)
    

• RegressGT — Reads logK's in Gastab output containing the almost finished Gastherm records, computes the regression coefficients, and inserts those into the fourth and last line of each record, in a copy of the input file.
• Input file: RegrunGT.dat. The first line should show an integer count of the records that follow.
  
• Output files: RegoutGT, RegpltGT.dat