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Edit thermo data


Penguin623
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Hi there,

 

Could you please let me know how I can edit the thermo data? It seems that I can only review the data without editing. I remember in the past with the text file I can go in to edit it. How about in GWB 10? Please let me know. Thank you very much for your help.

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Hi,

 

Most fields in the dataset, like species mol weight, ion size parameter, log Ks, etc. are editable. If you simply want to change a log K for a reaction, for example, just change the number in the appropriate box and click Apply. You'll then save the dataset as you would in the text file.

 

The TEdit thermo data editor has a tree structure on the left side where you can click the "+" button to expand the list for any section (Basis species, Redox couples, etc.). You can right-click on any of these section headers (or the species listed under them) then select "add" to add a new species to the dataset. You'll need to fill in information about the species and supply a reaction and log K if necessary.

 

For more information, see the TEdit section in the GWB Essentials Guide. You can also view some Tutorials for using TEdit here. Please let me know if you have a more specific question.

 

Regards,

 

Brian Farrell

Aqueous Solutions

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  • 3 weeks later...

Hi Brian,

 

Thanks a lot for your help. I can edit the thermo data now. Also, I have some other questions regarding to the "react" modeling. I put salt solutions as basis and put minerals as reactants. Is there anyway to show the mass change of reactants in the Gtplot? The minerals shown in the Gtplot is the "minerals in the system", right? And the "minerals in the system" is the newly precipitated minerals from the salt solutions after reaction, right? Please let me know your opinion. Thank you very much.

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Hi,

 

It depends how you set up your model. If you're implementing a titration path, then you're gradually adding a specified quantity of a mineral to your solution. The reaction progress will be tracked entirely by how much of the mineral you've added (Xi = 0 at the start, Xi = 1 when you've added all of the mineral). Whether it dissolves or not depends on the saturation state of the fluid with respect to that mineral. You can plot how much of the mineral has been added to the system by looking at the bottom of the "System Parameters" list in Gtplot. As for the variable type "Minerals", this refers to minerals that actually precipitate.

 

As an example, consider Ch29_caustic.rea in the GBRM scripts folder, from the Geochemical and Biogeochemical Reaction Modeling text. 40 grams of Dolomite wall rock are gradually titrated into a caustic wastewater. Initially, the Dolomite dissolves as it's added to the fluid (no value for Dolomite in "Minerals"), but eventually after about 33 grams dissolve it reaches saturation and about 7 grams accumulate in the system.

 

If you have a kinetic reactant, on the other hand, it will all be exposed to the fluid at the beginning of your reaction path. The kinetic rate law will determine how much of the mineral dissolves or precipitates as time goes by. You can plot how the mineral mass changes with time in this case.

 

Hope this helps,

Brian

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Hi Brian,

 

Thanks a lot for your reply. Say that I have the titration model, based on your suggestion, I can plot the minerals reacted. But in the XY plot, if I choose "minerals" as the variable type for Y, these minerals are the ones that system newly generated, right? They are the newly precipitated minerals from salt solutions after reaction, right? Please let me know your opinion. Thank you very much.

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When you choose "minerals" on the Y-axis, the list includes those initially present in the fluid, if any, those newly precipitated from the fluid, plus any kinetic minerals in contact with the system. It would not necessarily contain minerals being titrated into the system, because they might dissolve right away.

 

Here's a simpler example. Imagine you're slowly adding table salt to a glass of water. Initially all the salt being added dissolves, so Halite would plot on the X-axis as "mass reacted", but it wouldn't plot on the Y-axis as "minerals" until the fluid becomes saturated with respect to halite and the halite that's added stops dissolving.

 

Brian

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