Adding CO2 (g) to a solution

[Guelph_Alex]

Hi,

 

I need to add CO2(g) to a solution at 1 atm, 2 atm and 3 atm. How would I set this up using SpecE8. I have a starting pH of 6.7 and want to see how chaning the CO2(g) fugacity will influence my saturation states. I am running SpecE8 6.0.5 with thermo.dat. Thanks

Alex

[Tom Meuzelaar]

Hi,

 

I need to add CO2(g) to a solution at 1 atm, 2 atm and 3 atm. How would I set this up using SpecE8. I have a starting pH of 6.7 and want to see how chaning the CO2(g) fugacity will influence my saturation states. I am running SpecE8 6.0.5 with thermo.dat. Thanks

Alex

 

Hi Alex:

 

To set a fluid in equilibrium with a CO2 gas buffer in SpecE8 (or any GWB module):

 

• Add the HCO3- component to your Basis
  
• Swap CO2(g) in for bicarbonate
  
• Set its fugacity or log fugacity (1 atm ~ log fugacity -3.5)
  

 

Let me know if you have any additional questions.

 

Regards,

 

Tom Meuzelaar

RockWare, Inc.

[Azra]

Hi Alex:

 

To set a fluid in equilibrium with a CO2 gas buffer in SpecE8 (or any GWB module):

 

• Add the HCO3- component to your Basis
  
• Swap CO2(g) in for bicarbonate
  
• Set its fugacity or log fugacity (1 atm ~ log fugacity -3.5)
  

 

Let me know if you have any additional questions.

 

Regards,

 

Tom Meuzelaar

RockWare, Inc.

 

 

 

Hi,

I'd like to do the same by using the Script.sp8 file and i am not sure how to insert these comments in there. Thanks for any help,

Azra

[Tom Meuzelaar]

Hi,

I'd like to do the same by using the Script.sp8 file and i am not sure how to insert these comments in there. Thanks for any help,

Azra

 

Hi Azra:

 

Not sure I understand the question- do you just wish to see the actual/example SpecE8 script for the above example, or are you trying to populate the SpecE8 Basis using Tcl inside the script and script end commands?

 

Regards,

 

Tom

[Azra]

Hi Azra:

 

Not sure I understand the question- do you just wish to see the actual/example SpecE8 script for the above example, or are you trying to populate the SpecE8 Basis using Tcl inside the script and script end commands?

 

Regards,

 

Tom

 

Tom,

sorry for not being so clear earlier. I wish to populate the SpecE8 basis using tcl inside the script and script end commands. To be more exact, I am modifying the example Script.E8 file for multiple analysis according to my needs and I'd like to be able to fix CO2 to 1 atm during calculations and wasn't sure how to do it using tcl. I hope it is clear now.

Thanks,

Azra

[Tom Meuzelaar]

Tom,

sorry for not being so clear earlier. I wish to populate the SpecE8 basis using tcl inside. I am modifying the example Script.E8 file for multiple analysis to my needs and I'd like to be able to fix CO2 to 1 atm during calculations and wasn't sure how to do it using tcl. I hope it is clear now.

Thanks,

Azra

 

Hi Azra:

 

In SpecE8, assuming that all of your analyses have concentrations for the bicarbonate component, you can use the swap command (see p. 94 of the v7 Reference Guide):

 

swap CO2(g) for HCO3-

 

If you are running reaction path models in React, and wish to keep CO2 fixed beyond the initial speciation step, you should additionally use the fix command (p. 110 of the v7 Reference Guide).

 

Hope that helps,

 

Tom