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Tom

Gas Units in React

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I understand that gas is set in units of Fugacity in React. However, for output (e.g., when plotting CO2(g) exsolved as a function of rxn progress for carbonate dissolution), this unit has little meaning without the associated volume. What is the unit volume (for gas) assumed by React? I would like to use the volume to calculate a mass exsolved from the reported fugacity.

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I understand that gas is set in units of Fugacity in React. However, for output (e.g., when plotting CO2(g) exsolved as a function of rxn progress for carbonate dissolution), this unit has little meaning without the associated volume. What is the unit volume (for gas) assumed by React? I would like to use the volume to calculate a mass exsolved from the reported fugacity.

 

Hello:

 

Gas fugacities are reported in atm (atmosphere) units in GWB. Gas volumes are not tracked by the code.

 

Best regards,

 

Tom Meuzelaar

RockWare, Inc.

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Hello:

 

Gas fugacities are reported in atm (atmosphere) units in GWB. Gas volumes are not tracked by the code.

 

Best regards,

 

Tom Meuzelaar

RockWare, Inc.

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That doesn't make sense (unless I am missing something here). Sure, it works fine if you are trying to define a boundary condition. However, in the case where a gas is generated during reaction (e.g., CO2 exsolved during carbonate dissolution) GWB is clearly converting a finite mass of the species CO2(g) into a pressure (atm). To do so, a unit volume must be assumed (remember: PV=nRT). For the same amount of dissolution (and identical speciation) the fugacity (or partial pressure) would be completely different depending on the assumed size of the gas reservoir in contact with the mineral/solution mixture. When defining a boundary condition (e.g., atmospheric CO2) this reservoir is of infinite volume and a pressure is sufficient (n is assumed not to change, even though it is lost to the solution). However, when generating a finite mass of a gas it seems that the program must be assuming a unit volume of some sort, much like a unit volume of 1 liter (55 moles) is assumed for the solvent. What am I missing? How do I take the CO2(g) fugacity reported and calculate the mass of CO2(g) released from solution?

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That doesn't make sense (unless I am missing something here). Sure, it works fine if you are trying to define a boundary condition. However, in the case where a gas is generated during reaction (e.g., CO2 exsolved during carbonate dissolution) GWB is clearly converting a finite mass of the species CO2(g) into a pressure (atm). To do so, a unit volume must be assumed (remember: PV=nRT). For the same amount of dissolution (and identical speciation) the fugacity (or partial pressure) would be completely different depending on the assumed size of the gas reservoir in contact with the mineral/solution mixture. When defining a boundary condition (e.g., atmospheric CO2) this reservoir is of infinite volume and a pressure is sufficient (n is assumed not to change, even though it is lost to the solution). However, when generating a finite mass of a gas it seems that the program must be assuming a unit volume of some sort, much like a unit volume of 1 liter (55 moles) is assumed for the solvent. What am I missing? How do I take the CO2(g) fugacity reported and calculate the mass of CO2(g) released from solution?

 

Hi Tom:

 

You'll want to distinquish between the CO2(g) and CO2(aq) species in the database. The former simply represents a gas buffer that is modified in response to dissolved CO2 (the latter species) according to Henry's law. To track mass of CO2 released from solution, have a look at the change in the CO2(aq) species.

 

Hope that helps,

 

Tom Meuzelaar

RockWare, Inc.

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Tom,

Thanks for your patience and quick replies. It appears from your replies and from calculations I have performed on values in the output files that the gas fugacity is actually a HYPOTHETICAL fugacity--it is the fugacity that would be in equilibrium with the solved solution composition (where the solved solution composition does not include mass transfer to the gas phase). Consistent with this interpretation, it appears that the the mass balance neglects the gas phase. Furthermore, suppressing CO2(g) results in an identical final solution composition.

 

Again, although this is appropriate for the case of an effectively infinite gas buffer (e.g., ingassing from the atmosphere), it appears that REACT (at least in the case of how I have my model constructed) does not correctly simulate degassing. Specifically, the CO2(aq) values output by the model do not reflect any loss of CO2 to the gas phase (moles of CO2(aq) are consistently identical to moles of CaCO3 reacted, in spite of the rising CO2(g) fugacity). Is there a way to correctly simulate the degassing of CO2 during reaction using GWB?

 

Example React_Output.txt

 

Step # 0 Xi = 0.0000

Temperature = 25.0 C Pressure = 1.013 bars

pH = 2.000

Ionic strength = 0.005363

Charge imbalance = 0.010726 eq/kg (200% error)

Activity of water = 1.000000

Solvent mass = 1.000000 kg

Solution mass = 1.000011 kg

Solution density = 1.013 g/cm3

Chlorinity = 0.000000 molal

Dissolved solids = 11 mg/kg sol'n

Elect. conductivity = 3220.17 uS/cm (or umho/cm)

Hardness = 0.00 mg/kg sol'n as CaCO3

carbonate = 0.00 mg/kg sol'n as CaCO3

non-carbonate = 0.00 mg/kg sol'n as CaCO3

Rock mass = 0.000000 kg

Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3

Water type = H-OH

 

moles moles grams cm3

Reactants remaining reacted reacted reacted

----------------------------------------------------------------------------

Calcite 0.0009991 0.0000 0.0000 0.0000

 

No minerals in system.

 

Aqueous species molality mg/kg sol'n act. coef. log act.

---------------------------------------------------------------------------

H+ 0.01073 10.81 0.9323 -2.0000

(only species > 1e-8 molal listed)

 

Mineral saturation states

log Q/K log Q/K

----------------------------------------------------------------

(only minerals with log Q/K > -3 listed)

 

Gases fugacity log fug.

-----------------------------------------------

Steam 0.03131 -1.504

CO2(g) 2.798e-008 -7.553

 

In fluid Sorbed Kd

Original basis total moles moles mg/kg moles mg/kg L/kg

-------------------------------------------------------------------------------

Ca++ 9.87e-010 9.87e-010 3.96e-005

H+ 0.0107 0.0107 10.8

H2O 55.5 55.5 1.00e+006

HCO3- 9.87e-010 9.87e-010 6.02e-005

 

Elemental composition In fluid Sorbed

total moles moles mg/kg moles mg/kg

-------------------------------------------------------------------------------

Calcium 9.874e-010 9.874e-010 3.957e-005

Carbon 9.874e-010 9.874e-010 1.186e-005

Hydrogen 111.0 111.0 1.119e+005

Oxygen 55.51 55.51 8.881e+005

 

 

Step # 10 Xi = 0.1000

Temperature = 25.0 C Pressure = 1.013 bars

pH = 2.008

Ionic strength = 0.005463

Charge imbalance = 0.010726 eq/kg (200% error)

Activity of water = 1.000000

Solvent mass = 1.000002 kg

Solution mass = 1.000021 kg

Solution density = 1.013 g/cm3

Chlorinity = 0.000000 molal

Dissolved solids = 19 mg/kg sol'n

Elect. conductivity = 3166.29 uS/cm (or umho/cm)

Hardness = 10.00 mg/kg sol'n as CaCO3

carbonate = 0.00 mg/kg sol'n as CaCO3

non-carbonate = 10.00 mg/kg sol'n as CaCO3

Rock mass = 0.000000 kg

Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3

Water type = H-HCO3

 

moles moles grams cm3

Reactants remaining reacted reacted reacted

----------------------------------------------------------------------------

Calcite 0.0008992 9.991e-005 0.01000 0.003690

 

No minerals in system.

 

Aqueous species molality mg/kg sol'n act. coef. log act.

---------------------------------------------------------------------------

H+ 0.01053 10.61 0.9318 -2.0084

Ca++ 9.991e-005 4.004 0.7393 -4.1316

CO2(aq) 9.991e-005 4.397 1.0000 -4.0004

(only species > 1e-8 molal listed)

 

Mineral saturation states

log Q/K log Q/K

----------------------------------------------------------------

(only minerals with log Q/K > -3 listed)

 

Gases fugacity log fug.

-----------------------------------------------

Steam 0.03131 -1.504

CO2(g) 0.002831 -2.548

 

In fluid Sorbed Kd

Original basis total moles moles mg/kg moles mg/kg L/kg

-------------------------------------------------------------------------------

Ca++ 9.99e-005 9.99e-005 4.00

H+ 0.0106 0.0106 10.7

H2O 55.5 55.5 1.00e+006

HCO3- 9.99e-005 9.99e-005 6.10

 

Elemental composition In fluid Sorbed

total moles moles mg/kg moles mg/kg

-------------------------------------------------------------------------------

Calcium 9.991e-005 9.991e-005 4.004

Carbon 9.991e-005 9.991e-005 1.200

Hydrogen 111.0 111.0 1.119e+005

Oxygen 55.51 55.51 8.881e+005

 

 

Step # 20 Xi = 0.2000

Temperature = 25.0 C Pressure = 1.013 bars

pH = 2.017

Ionic strength = 0.005563

Charge imbalance = 0.010726 eq/kg (200% error)

Activity of water = 1.000000

Solvent mass = 1.000004 kg

Solution mass = 1.000031 kg

Solution density = 1.013 g/cm3

Chlorinity = 0.000000 molal

Dissolved solids = 27 mg/kg sol'n

Elect. conductivity = 3112.59 uS/cm (or umho/cm)

Hardness = 20.00 mg/kg sol'n as CaCO3

carbonate = 0.00 mg/kg sol'n as CaCO3

non-carbonate = 20.00 mg/kg sol'n as CaCO3

Rock mass = 0.000000 kg

Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3

Water type = H-HCO3

 

moles moles grams cm3

Reactants remaining reacted reacted reacted

----------------------------------------------------------------------------

Calcite 0.0007993 0.0001998 0.02000 0.007380

 

No minerals in system.

 

Aqueous species molality mg/kg sol'n act. coef. log act.

---------------------------------------------------------------------------

H+ 0.01033 10.41 0.9313 -2.0169

Ca++ 0.0001998 8.009 0.7375 -3.8316

CO2(aq) 0.0001998 8.793 1.0000 -3.6994

(only species > 1e-8 molal listed)

 

Mineral saturation states

log Q/K log Q/K

----------------------------------------------------------------

(only minerals with log Q/K > -3 listed)

 

Gases fugacity log fug.

-----------------------------------------------

Steam 0.03131 -1.504

CO2(g) 0.005663 -2.247

 

In fluid Sorbed Kd

Original basis total moles moles mg/kg moles mg/kg L/kg

-------------------------------------------------------------------------------

Ca++ 0.000200 0.000200 8.01

H+ 0.0105 0.0105 10.6

H2O 55.5 55.5 1.00e+006

HCO3- 0.000200 0.000200 12.2

 

Elemental composition In fluid Sorbed

total moles moles mg/kg moles mg/kg

-------------------------------------------------------------------------------

Calcium 0.0001998 0.0001998 8.009

Carbon 0.0001998 0.0001998 2.400

Hydrogen 111.0 111.0 1.119e+005

Oxygen 55.51 55.51 8.881e+005

 

 

Step # 30 Xi = 0.3000

Temperature = 25.0 C Pressure = 1.013 bars

pH = 2.026

Ionic strength = 0.005663

Charge imbalance = 0.010726 eq/kg (200% error)

Activity of water = 1.000000

Solvent mass = 1.000005 kg

Solution mass = 1.000041 kg

Solution density = 1.013 g/cm3

Chlorinity = 0.000000 molal

Dissolved solids = 35 mg/kg sol'n

Elect. conductivity = 3059.07 uS/cm (or umho/cm)

Hardness = 30.00 mg/kg sol'n as CaCO3

carbonate = 0.00 mg/kg sol'n as CaCO3

non-carbonate = 30.00 mg/kg sol'n as CaCO3

Rock mass = 0.000000 kg

Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3

Water type = H-HCO3

 

moles moles grams cm3

Reactants remaining reacted reacted reacted

----------------------------------------------------------------------------

Calcite 0.0006994 0.0002997 0.03000 0.01107

 

No minerals in system.

 

Aqueous species molality mg/kg sol'n act. coef. log act.

---------------------------------------------------------------------------

H+ 0.01013 10.21 0.9309 -2.0257

Ca++ 0.0002997 12.01 0.7358 -3.6565

CO2(aq) 0.0002997 13.19 1.0000 -3.5233

HCO3- 1.481e-008 0.0009038 0.9242 -7.8636

(only species > 1e-8 molal listed)

 

Mineral saturation states

log Q/K log Q/K

----------------------------------------------------------------

(only minerals with log Q/K > -3 listed)

 

Gases fugacity log fug.

-----------------------------------------------

Steam 0.03131 -1.504

CO2(g) 0.008494 -2.071

 

In fluid Sorbed Kd

Original basis total moles moles mg/kg moles mg/kg L/kg

-------------------------------------------------------------------------------

Ca++ 0.000300 0.000300 12.0

H+ 0.0104 0.0104 10.5

H2O 55.5 55.5 1.00e+006

HCO3- 0.000300 0.000300 18.3

 

Elemental composition In fluid Sorbed

total moles moles mg/kg moles mg/kg

-------------------------------------------------------------------------------

Calcium 0.0002997 0.0002997 12.01

Carbon 0.0002997 0.0002997 3.600

Hydrogen 111.0 111.0 1.119e+005

Oxygen 55.51 55.51 8.881e+005

 

 

Step # 40 Xi = 0.4000

Temperature = 25.0 C Pressure = 1.013 bars

pH = 2.035

Ionic strength = 0.005763

Charge imbalance = 0.010725 eq/kg (200% error)

Activity of water = 1.000000

Solvent mass = 1.000007 kg

Solution mass = 1.000051 kg

Solution density = 1.013 g/cm3

Chlorinity = 0.000000 molal

Dissolved solids = 44 mg/kg sol'n

Elect. conductivity = 3005.71 uS/cm (or umho/cm)

Hardness = 40.00 mg/kg sol'n as CaCO3

carbonate = 0.00 mg/kg sol'n as CaCO3

non-carbonate = 40.00 mg/kg sol'n as CaCO3

Rock mass = 0.000000 kg

Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3

Water type = H-HCO3

 

moles moles grams cm3

Reactants remaining reacted reacted reacted

----------------------------------------------------------------------------

Calcite 0.0005995 0.0003996 0.04000 0.01476

 

No minerals in system.

 

Aqueous species molality mg/kg sol'n act. coef. log act.

---------------------------------------------------------------------------

H+ 0.009927 10.00 0.9304 -2.0345

Ca++ 0.0003996 16.02 0.7341 -3.5326

CO2(aq) 0.0003996 17.59 1.0000 -3.3984

HCO3- 2.017e-008 0.001231 0.9236 -7.7298

(only species > 1e-8 molal listed)

 

Mineral saturation states

log Q/K log Q/K

----------------------------------------------------------------

(only minerals with log Q/K > -3 listed)

 

Gases fugacity log fug.

-----------------------------------------------

Steam 0.03131 -1.504

CO2(g) 0.01133 -1.946

 

In fluid Sorbed Kd

Original basis total moles moles mg/kg moles mg/kg L/kg

-------------------------------------------------------------------------------

Ca++ 0.000400 0.000400 16.0

H+ 0.0103 0.0103 10.4

H2O 55.5 55.5 1.00e+006

HCO3- 0.000400 0.000400 24.4

 

Elemental composition In fluid Sorbed

total moles moles mg/kg moles mg/kg

-------------------------------------------------------------------------------

Calcium 0.0003996 0.0003996 16.02

Carbon 0.0003996 0.0003996 4.800

Hydrogen 111.0 111.0 1.119e+005

Oxygen 55.51 55.51 8.881e+005

 

 

Step # 50 Xi = 0.5000

Temperature = 25.0 C Pressure = 1.013 bars

pH = 2.044

Ionic strength = 0.005863

Charge imbalance = 0.010725 eq/kg (200% error)

Activity of water = 1.000000

Solvent mass = 1.000009 kg

Solution mass = 1.000061 kg

Solution density = 1.013 g/cm3

Chlorinity = 0.000000 molal

Dissolved solids = 52 mg/kg sol'n

Elect. conductivity = 2952.52 uS/cm (or umho/cm)

Hardness = 50.00 mg/kg sol'n as CaCO3

carbonate = 0.00 mg/kg sol'n as CaCO3

non-carbonate = 50.00 mg/kg sol'n as CaCO3

Rock mass = 0.000000 kg

Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3

Water type = H-HCO3

 

moles moles grams cm3

Reactants remaining reacted reacted reacted

----------------------------------------------------------------------------

Calcite 0.0004996 0.0004996 0.05000 0.01845

 

No minerals in system.

 

Aqueous species molality mg/kg sol'n act. coef. log act.

---------------------------------------------------------------------------

H+ 0.009727 9.803 0.9299 -2.0436

Ca++ 0.0004996 20.02 0.7324 -3.4367

CO2(aq) 0.0004995 21.98 1.0000 -3.3014

HCO3- 2.576e-008 0.001572 0.9230 -7.6239

(only species > 1e-8 molal listed)

 

Mineral saturation states

log Q/K log Q/K

----------------------------------------------------------------

(only minerals with log Q/K > -3 listed)

 

Gases fugacity log fug.

-----------------------------------------------

Steam 0.03131 -1.504

CO2(g) 0.01416 -1.849

 

In fluid Sorbed Kd

Original basis total moles moles mg/kg moles mg/kg L/kg

-------------------------------------------------------------------------------

Ca++ 0.000500 0.000500 20.0

H+ 0.0102 0.0102 10.3

H2O 55.5 55.5 1.00e+006

HCO3- 0.000500 0.000500 30.5

 

Elemental composition In fluid Sorbed

total moles moles mg/kg moles mg/kg

-------------------------------------------------------------------------------

Calcium 0.0004996 0.0004996 20.02

Carbon 0.0004996 0.0004996 6.000

Hydrogen 111.0 111.0 1.119e+005

Oxygen 55.51 55.51 8.881e+005

 

 

Step # 60 Xi = 0.6000

Temperature = 25.0 C Pressure = 1.013 bars

pH = 2.053

Ionic strength = 0.005962

Charge imbalance = 0.010725 eq/kg (200% error)

Activity of water = 1.000000

Solvent mass = 1.000011 kg

Solution mass = 1.000071 kg

Solution density = 1.013 g/cm3

Chlorinity = 0.000000 molal

Dissolved solids = 60 mg/kg sol'n

Elect. conductivity = 2899.50 uS/cm (or umho/cm)

Hardness = 60.00 mg/kg sol'n as CaCO3

carbonate = 0.00 mg/kg sol'n as CaCO3

non-carbonate = 59.99 mg/kg sol'n as CaCO3

Rock mass = 0.000000 kg

Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3

Water type = H-HCO3

 

moles moles grams cm3

Reactants remaining reacted reacted reacted

----------------------------------------------------------------------------

Calcite 0.0003996 0.0005995 0.06000 0.02214

 

No minerals in system.

 

Aqueous species molality mg/kg sol'n act. coef. log act.

---------------------------------------------------------------------------

H+ 0.009527 9.602 0.9295 -2.0528

Ca++ 0.0005995 24.02 0.7307 -3.3585

CO2(aq) 0.0005994 26.38 1.0000 -3.2223

HCO3- 3.159e-008 0.001928 0.9225 -7.5354

(only species > 1e-8 molal listed)

 

Mineral saturation states

log Q/K log Q/K

----------------------------------------------------------------

(only minerals with log Q/K > -3 listed)

 

Gases fugacity log fug.

-----------------------------------------------

Steam 0.03131 -1.504

CO2(g) 0.01699 -1.770

 

In fluid Sorbed Kd

Original basis total moles moles mg/kg moles mg/kg L/kg

-------------------------------------------------------------------------------

Ca++ 0.000599 0.000599 24.0

H+ 0.0101 0.0101 10.2

H2O 55.5 55.5 1.00e+006

HCO3- 0.000599 0.000599 36.6

 

Elemental composition In fluid Sorbed

total moles moles mg/kg moles mg/kg

-------------------------------------------------------------------------------

Calcium 0.0005995 0.0005995 24.02

Carbon 0.0005995 0.0005995 7.200

Hydrogen 111.0 111.0 1.119e+005

Oxygen 55.51 55.51 8.881e+005

 

 

Step # 70 Xi = 0.7000

Temperature = 25.0 C Pressure = 1.013 bars

pH = 2.062

Ionic strength = 0.006062

Charge imbalance = 0.010725 eq/kg (200% error)

Activity of water = 1.000000

Solvent mass = 1.000013 kg

Solution mass = 1.000081 kg

Solution density = 1.013 g/cm3

Chlorinity = 0.000000 molal

Dissolved solids = 68 mg/kg sol'n

Elect. conductivity = 2846.64 uS/cm (or umho/cm)

Hardness = 69.99 mg/kg sol'n as CaCO3

carbonate = 0.00 mg/kg sol'n as CaCO3

non-carbonate = 69.99 mg/kg sol'n as CaCO3

Rock mass = 0.000000 kg

Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3

Water type = H-HCO3

 

moles moles grams cm3

Reactants remaining reacted reacted reacted

----------------------------------------------------------------------------

Calcite 0.0002997 0.0006994 0.07000 0.02583

 

No minerals in system.

 

Aqueous species molality mg/kg sol'n act. coef. log act.

---------------------------------------------------------------------------

H+ 0.009327 9.400 0.9290 -2.0622

Ca++ 0.0006994 28.03 0.7290 -3.2925

CO2(aq) 0.0006993 30.78 1.0000 -3.1553

HCO3- 3.769e-008 0.002300 0.9219 -7.4591

(only species > 1e-8 molal listed)

 

Mineral saturation states

log Q/K log Q/K

----------------------------------------------------------------

(only minerals with log Q/K > -3 listed)

 

Gases fugacity log fug.

-----------------------------------------------

Steam 0.03131 -1.504

CO2(g) 0.01982 -1.703

 

In fluid Sorbed Kd

Original basis total moles moles mg/kg moles mg/kg L/kg

-------------------------------------------------------------------------------

Ca++ 0.000699 0.000699 28.0

H+ 0.0100 0.0100 10.1

H2O 55.5 55.5 1.00e+006

HCO3- 0.000699 0.000699 42.7

 

Elemental composition In fluid Sorbed

total moles moles mg/kg moles mg/kg

-------------------------------------------------------------------------------

Calcium 0.0006994 0.0006994 28.03

Carbon 0.0006994 0.0006994 8.400

Hydrogen 111.0 111.0 1.119e+005

Oxygen 55.51 55.51 8.881e+005

 

 

Step # 80 Xi = 0.8000

Temperature = 25.0 C Pressure = 1.013 bars

pH = 2.072

Ionic strength = 0.006162

Charge imbalance = 0.010725 eq/kg (200% error)

Activity of water = 1.000000

Solvent mass = 1.000014 kg

Solution mass = 1.000091 kg

Solution density = 1.013 g/cm3

Chlorinity = 0.000000 molal

Dissolved solids = 76 mg/kg sol'n

Elect. conductivity = 2793.93 uS/cm (or umho/cm)

Hardness = 79.99 mg/kg sol'n as CaCO3

carbonate = 0.00 mg/kg sol'n as CaCO3

non-carbonate = 79.99 mg/kg sol'n as CaCO3

Rock mass = 0.000000 kg

Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3

Water type = H-HCO3

 

moles moles grams cm3

Reactants remaining reacted reacted reacted

----------------------------------------------------------------------------

Calcite 0.0001998 0.0007993 0.08000 0.02952

 

No minerals in system.

 

Aqueous species molality mg/kg sol'n act. coef. log act.

---------------------------------------------------------------------------

H+ 0.009127 9.199 0.9286 -2.0719

Ca++ 0.0007993 32.03 0.7274 -3.2355

CO2(aq) 0.0007992 35.17 1.0000 -3.0973

HCO3- 4.406e-008 0.002688 0.9214 -7.3915

(only species > 1e-8 molal listed)

 

Mineral saturation states

log Q/K log Q/K

----------------------------------------------------------------

(only minerals with log Q/K > -3 listed)

 

Gases fugacity log fug.

-----------------------------------------------

Steam 0.03131 -1.504

CO2(g) 0.02265 -1.645

 

In fluid Sorbed Kd

Original basis total moles moles mg/kg moles mg/kg L/kg

-------------------------------------------------------------------------------

Ca++ 0.000799 0.000799 32.0

H+ 0.00993 0.00993 10.0

H2O 55.5 55.5 1.00e+006

HCO3- 0.000799 0.000799 48.8

 

Elemental composition In fluid Sorbed

total moles moles mg/kg moles mg/kg

-------------------------------------------------------------------------------

Calcium 0.0007993 0.0007993 32.03

Carbon 0.0007993 0.0007993 9.599

Hydrogen 111.0 111.0 1.119e+005

Oxygen 55.51 55.51 8.881e+005

 

 

Step # 90 Xi = 0.9000

Temperature = 25.0 C Pressure = 1.013 bars

pH = 2.082

Ionic strength = 0.006262

Charge imbalance = 0.010725 eq/kg (200% error)

Activity of water = 1.000000

Solvent mass = 1.000016 kg

Solution mass = 1.000101 kg

Solution density = 1.013 g/cm3

Chlorinity = 0.000000 molal

Dissolved solids = 85 mg/kg sol'n

Elect. conductivity = 2741.38 uS/cm (or umho/cm)

Hardness = 89.99 mg/kg sol'n as CaCO3

carbonate = 0.00 mg/kg sol'n as CaCO3

non-carbonate = 89.99 mg/kg sol'n as CaCO3

Rock mass = 0.000000 kg

Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3

Water type = H-HCO3

 

moles moles grams cm3

Reactants remaining reacted reacted reacted

----------------------------------------------------------------------------

Calcite 9.991e-005 0.0008992 0.09000 0.03321

 

No minerals in system.

 

Aqueous species molality mg/kg sol'n act. coef. log act.

---------------------------------------------------------------------------

H+ 0.008927 8.997 0.9281 -2.0817

Ca++ 0.0008992 36.04 0.7258 -3.1853

CO2(aq) 0.0008991 39.57 1.0000 -3.0462

HCO3- 5.074e-008 0.003096 0.9208 -7.3305

(only species > 1e-8 molal listed)

 

Mineral saturation states

log Q/K log Q/K

----------------------------------------------------------------

(only minerals with log Q/K > -3 listed)

 

Gases fugacity log fug.

-----------------------------------------------

Steam 0.03131 -1.504

CO2(g) 0.02548 -1.594

 

In fluid Sorbed Kd

Original basis total moles moles mg/kg moles mg/kg L/kg

-------------------------------------------------------------------------------

Ca++ 0.000899 0.000899 36.0

H+ 0.00983 0.00983 9.90

H2O 55.5 55.5 1.00e+006

HCO3- 0.000899 0.000899 54.9

 

Elemental composition In fluid Sorbed

total moles moles mg/kg moles mg/kg

-------------------------------------------------------------------------------

Calcium 0.0008992 0.0008992 36.04

Carbon 0.0008992 0.0008992 10.80

Hydrogen 111.0 111.0 1.119e+005

Oxygen 55.51 55.51 8.881e+005

 

 

Step # 100 Xi = 1.0000

Temperature = 25.0 C Pressure = 1.013 bars

pH = 2.092

Ionic strength = 0.006362

Charge imbalance = 0.010725 eq/kg (200% error)

Activity of water = 1.000000

Solvent mass = 1.000018 kg

Solution mass = 1.000111 kg

Solution density = 1.013 g/cm3

Chlorinity = 0.000000 molal

Dissolved solids = 93 mg/kg sol'n

Elect. conductivity = 2688.98 uS/cm (or umho/cm)

Hardness = 99.99 mg/kg sol'n as CaCO3

carbonate = 0.00 mg/kg sol'n as CaCO3

non-carbonate = 99.99 mg/kg sol'n as CaCO3

Rock mass = 0.000000 kg

Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3

Water type = H-HCO3

 

moles moles grams cm3

Reactants remaining reacted reacted reacted

----------------------------------------------------------------------------

Calcite 7.149e-019 0.0009991 0.1000 0.03690

 

No minerals in system.

 

Aqueous species molality mg/kg sol'n act. coef. log act.

---------------------------------------------------------------------------

H+ 0.008728 8.796 0.9277 -2.0917

Ca++ 0.0009991 40.04 0.7242 -3.1405

CO2(aq) 0.0009990 43.96 1.0000 -3.0004

HCO3- 5.772e-008 0.003522 0.9203 -7.2747

(only species > 1e-8 molal listed)

 

Mineral saturation states

log Q/K log Q/K

----------------------------------------------------------------

(only minerals with log Q/K > -3 listed)

 

Gases fugacity log fug.

-----------------------------------------------

Steam 0.03131 -1.504

CO2(g) 0.02831 -1.548

 

In fluid Sorbed Kd

Original basis total moles moles mg/kg moles mg/kg L/kg

-------------------------------------------------------------------------------

Ca++ 0.000999 0.000999 40.0

H+ 0.00973 0.00973 9.80

H2O 55.5 55.5 1.00e+006

HCO3- 0.000999 0.000999 61.0

 

Elemental composition In fluid Sorbed

total moles moles mg/kg moles mg/kg

-------------------------------------------------------------------------------

Calcium 0.0009991 0.0009991 40.04

Carbon 0.0009991 0.0009991 12.00

Hydrogen 111.0 111.0 1.119e+005

Oxygen 55.51 55.51 8.881e+005

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Is there a way to correctly simulate the degassing of CO2 during reaction using GWB?

 

Sure- you can do this in the Reactants tab using the slide option. Choose add - Sliding, and then pick either a sliding CO2(g) fugacity or a sliding CO2(aq) activity. Note that you also have options to fix CO2 fugacity or activity.

 

Regards,

 

Tom

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Sure- you can do this in the Reactants tab using the slide option. Choose add - Sliding, and then pick either a sliding CO2(g) fugacity or a sliding CO2(aq) activity. Note that you also have options to fix CO2 fugacity or activity.

 

Regards,

 

Tom

 

So in order to have the mass transfer to the gas phase accounted for, it must be defined as a reactant? (and therefore can not be solved for?)

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So in order to have the mass transfer to the gas phase accounted for, it must be defined as a reactant? (and therefore can not be solved for?)

 

You can calculate partitioning between the dissolved CO2 and CO2 gas using a simple speciation model- but to answer the question I think you are asking- GWB does not track gas phase masses or volumes.

 

Regards,

 

Tom Meuzelaar

RockWare, Inc.

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