wbourcier
-
Posts
4 -
Joined
-
Last visited
Posts posted by wbourcier
-
-
Thanks.
I am guessing one would only see a change in component masses (vs change in distribution of species) when starting with a system that is constrained in a kind of unusual manner (typical for pickup files). I have never noticed this for input files where I specifically constrain component masses.
Thanks for your analysis!
bill
-
script attached below
I will send dataset via email
FIRST STEP- REACT Na-CARBONATE CAPTURE SOLUTION WITH CO2
Temperature is 25 C
Thermo dataset: C:\Program Files\Gwb\Gtdata\thermo_da0ypfR2.wlbrev9.dat
Working directory: c:\users\bourcier1\desktop\nahcolitetests\katherinepapercalcs
Options: H-M-W
Basis is:
H2O 1 free kg
CO3-- (swapped for HCO3-) 1.935 molal
Na+ 3.87 molal
OH- (swapped for H+) charge balance
Reactants:
Slide fugacity of CO2(g) to .1
Elemental composition In fluid Sorbed
total moles moles mg/kg moles mg/kg
-------------------------------------------------------------------------------
Carbon 3.771 1.176 1.322e+04
Hydrogen 111.0 108.4 1.023e+05
Oxygen 64.99 57.21 8.570e+05
Sodium 3.870 1.274 2.743e+04
Pickup system and re-run to confirm masses remain the same
Elemental composition In fluid Sorbed
total moles moles mg/kg moles mg/kg
-------------------------------------------------------------------------------
Carbon 3.771 1.176 1.322e+04
Hydrogen 111.0 108.4 1.023e+05
Oxygen 64.99 57.21 8.570e+05
Sodium 3.870 1.274 2.743e+04
Fix CO2 fugacity and re-run
Elemental composition In fluid Sorbed
total moles moles mg/kg moles mg/kg
-------------------------------------------------------------------------------
Carbon 3.771 1.176 1.322e+04
Hydrogen 111.0 108.4 1.023e+05
Oxygen 64.99 57.21 8.570e+05
Sodium 3.870 1.274 2.743e+04
Now add temperature path starting at 25 C – here the masses have changed
Elemental composition In fluid Sorbed
total moles moles mg/kg moles mg/kg
-------------------------------------------------------------------------------
Carbon 3.842 1.247 1.394e+04
Hydrogen 111.1 108.5 1.018e+05
Oxygen 65.21 57.42 8.552e+05
Sodium 3.953 1.357 2.905e+04
verbatim input commands:
React> show
Temperature is 25 C
Thermo dataset: C:\Program Files\Gwb\Gtdata\thermo_da0ypfR2.wlbrev9.dat
Working directory: c:\users\bourcier1\desktop\nahcolitetests\katherinepapercalcs
Options: H-M-W
Basis is:
H2O 1 free kg
CO3-- (swapped for HCO3-) 1.935 molal
Na+ 3.87 molal
OH- (swapped for H+) charge balance
Reactants:
Slide fugacity of CO2(g) to .1
React> go
React> pickup system
React> show
Temperature is 25 C
Thermo dataset: C:\Program Files\Gwb\Gtdata\thermo_da0ypfR2.wlbrev9.dat
Working directory: c:\users\bourcier1\desktop\nahcolitetests\katherinepapercalcs
Options: H-M-W
Basis is:
H2O .9670762346433 free kg guess = 53.58010637651
HCO3- 1.175844707556 mol guess = 1.108927423502
Nahcolite (swapped for Na+) 2.595535888509 free mol guess = 3.87
CO2(g) (swapped for H+) .1 fugacity guess = -.09861940394104
No reactants specified.
React> bal HCO3-
React> go
React> fix fug CO2(g)
React> go
React> temp start 25 end 110
React> go
React> show
Initial temperature is 25 C, final is 110 C
Thermo dataset: C:\Program Files\Gwb\Gtdata\thermo_da0ypfR2.wlbrev9.dat
Working directory: c:\users\bourcier1\desktop\nahcolitetests\katherinepapercalcs
Options: H-M-W
Basis is:
H2O .9670762346433 free kg guess = 53.58010637651
HCO3- 1.175844707556 mol guess = 1.108927423502 (charge balance species)
Nahcolite (swapped for Na+) 2.595535888509 free mol guess = 3.87
CO2(g) (swapped for H+) .1 fugacity guess = -.09861940394104
Reactants:
Fix fugacity of CO2(g)
Other "show" options: type "show show"
React>
-
I get an unexpected change in elemental masses after using "pickup" command
and starting a polythermal simulation. I also hold a gas fugacity constant.
if I run the picked-up system without a temperature change I get one result, if I add the temperature path I get another (both at the starting condition)
Using Pitzer option
-----------------------------------
Model loading of sodium carbonate with CO2 during flue gas CO2 capture
The problem is that in using “pickup” command and fix fug command, the system changes composition
React> pickup system
React> show
Temperature is 25 C
Thermo dataset: C:\Program Files\Gwb\Gtdata\thermo_da0ypfR2.wlbrev9.dat
Working directory: c:\users\bourcier1\desktop\nahcolitetests\katherinepapercalcs
Options: H-M-W
Basis is:
H2O .9670762346433 free kg guess = 53.58010637651
HCO3- 1.175844707556 mol guess = 1.108927423502
Nahcolite (swapped for Na+) 2.595535888509 free mol guess = 3.87
CO2(g) (swapped for H+) .1 fugacity guess = -.09861940394104
No reactants specified.
React> HCO3- bal (system will not converge unless I change charge balance species – common issue with pickup command)
React> go
Step # 0 Xi = 0.0000
Temperature = 25.0 C Pressure = 1.013 bars
pH = 8.561
Ionic strength = 1.422313
Activity of water = 0.962599
Solvent mass = 0.967076 kg
Solution mass = 1.067985 kg
Solution density = 1.058 g/cm3
Chlorinity = 0.000000 molal
Dissolved solids = 94485 mg/kg sol'n
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 = 0.218043 kg
Carbonate alkalinity= 59724.18 mg/kg sol'n as CaCO3
Water type = Na-HCO3
Minerals in system moles log moles grams volume (cm3)
----------------------------------------------------------------------------
Nahcolite 2.596 0.414 218.0 100.2
_____________ _____________
(total) 218.0 100.2
Aqueous species molality mg/kg sol'n act. coef. log act.
---------------------------------------------------------------------------
Na+ 1.318 2.743e+04 0.5367 -0.1504
HCO3- 1.109 6.127e+04 0.4848 -0.2696
CO3-- 0.1045 5676. 0.0878 -2.0378
CO2(aq) 0.002488 99.17 1.3651 -2.4689
OH- 5.320e-06 0.08193 0.6653 -5.4511
(only species > 1e-8 molal listed)
Mineral saturation states
log Q/K log Q/K
----------------------------------------------------------------
Nahcolite 0.0000 sat Na2CO3:7H2O -2.0257
Natron -1.7754 Thermonatrite -2.8964
Trona -1.9490
(only minerals with log Q/K > -3 listed)
Gases fugacity log fug.
-----------------------------------------------
CO2(g) 0.1000 -1.000
H2O(g) 0.03045 -1.516
In fluid Sorbed Kd
Original basis total moles moles mg/kg moles mg/kg L/kg
-------------------------------------------------------------------------------
H+ -0.0986 -0.0986 -93.1
H2O 53.7 53.7 9.05e+05
HCO3- 3.77 1.18 6.72e+04
Na+ 3.87 1.27 2.74e+04
Elemental composition In fluid Sorbed
total moles moles mg/kg moles mg/kg
-------------------------------------------------------------------------------
Carbon 3.771 1.176 1.322e+04
Hydrogen 111.0 108.4 1.023e+05
Oxygen 64.99 57.21 8.570e+05
Sodium 3.870 1.274 2.743e+04
Now heat the system holding PCO2 constant – first step should reproduce the output file from above
React> fix fug CO2(g)
React> temp start 25 end 110
React> go
Since the starting temperature has not changed I expect to see the same output at step 0
But elemental composition has changed (see blue highlight below)
PCO2 is at 0.1 bars in both cases, temperature is 25 C in both cases
Step # 0 Xi = 0.0000
Temperature = 25.0 C Pressure = 1.013 bars
pH = 8.581
Ionic strength = 1.520600
Activity of water = 0.960372
Solvent mass = 0.967076 kg
Solution mass = 1.074209 kg
Solution density = 1.061 g/cm3
Chlorinity = 0.000000 molal
Dissolved solids = 99732 mg/kg sol'n
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 = 0.218043 kg
Carbonate alkalinity= 63244.90 mg/kg sol'n as CaCO3
Water type = Na-HCO3
moles moles grams cm3
Reactants remaining reacted reacted reacted
----------------------------------------------------------------------------
CO2(g) -- fixed fugacity buffer --
Minerals in system moles log moles grams volume (cm3)
----------------------------------------------------------------------------
Nahcolite 2.596 0.414 218.0 100.2
_____________ _____________
(total) 218.0 100.2
Aqueous species molality mg/kg sol'n act. coef. log act.
---------------------------------------------------------------------------
Na+ 1.404 2.905e+04 0.5331 -0.1259
HCO3- 1.170 6.426e+04 0.4778 -0.2526
CO3-- 0.1169 6317. 0.0837 -2.0095
CO2(aq) 0.002486 98.48 1.3932 -2.4606
OH- 5.422e-06 0.08301 0.6666 -5.4420
(only species > 1e-8 molal listed)
Mineral saturation states
log Q/K log Q/K
----------------------------------------------------------------
Nahcolite 0.0000 sat Na2CO3:7H2O -2.0318
Natron -1.7844 Thermonatrite -2.8765
Trona -1.8217
(only minerals with log Q/K > -3 listed)
Gases fugacity log fug.
-----------------------------------------------
CO2(g) 0.1000 -1.000
H2O(g) 0.03012 -1.521
In fluid Sorbed Kd
Original basis total moles moles mg/kg moles mg/kg L/kg
-------------------------------------------------------------------------------
H+ -0.111 -0.111 -104.
H2O 53.7 53.7 9.00e+05
HCO3- 3.84 1.25 7.08e+04
Na+ 3.95 1.36 2.91e+04
Elemental composition In fluid Sorbed
total moles moles mg/kg moles mg/kg
-------------------------------------------------------------------------------
Carbon 3.842 1.247 1.394e+04
Hydrogen 111.1 108.5 1.018e+05
Oxygen 65.21 57.42 8.552e+05
Sodium 3.953 1.357 2.905e+04
Elemental composition has changed – but I did not change it!
Electrochemical reactions
in General modeling discussion
Posted
Has anyone used GWB to model electrochemical processes (driven by externally applied voltage)?
Can you swap in e- for O2(aq) and use e- as a reactant? Or do mass balance using e- as a proxy for current into or out of the system?
I have tried and gotten error messages, but maybe there are workarounds? I am trying to model chemical reactions in a CO2 reduction reaction.
Thanks for any help or advice!
Bill