Kinetic Model problem

[Ozan]

Hey,

I attached react and a surface data file that I have used in that react folder. This model should give me results of precipitation, dissolution, adsorbed/desorbed species related to co2 concentration in the system. However, except calcite (which has a significantly higher kinetic rate constant), I can not see any change in the other minerals in terms of mg. I tried using longer time intervals, still change in other minerals are 0 mg. I expected to see dissolution of albite, illite (which I see very small change) and precipitation of kaolinite and quartz. I would be happy if you could let me know if this problem is due to very small kinetic constants or am I building it wrong. I would appreciate any other advice related to the model (if there is any better way to assign minerals or species etc). Here is the link for the kinetic constants if you would like to check if I put them in a correct way https://pubs.usgs.gov/of/2004/1068/pdf/OFR_2004_1068.pdf .

 

Thanks,

 

Ozan

kinetic_model.rea illitecationexchange.sdat

[Jia Wang]

Hello Ozan,

I think the primary issue with your input file is that you have not specify a nucleus density for the minerals in the Reactants pane. If your mineral is not present in your chemical system, for example Dawsonite, then it will not form according to your kinetic rate law in your simulation since the surface area for a non-existing mineral is 0. You can set for any kinetic mineral a simple description of nucleation by setting the nucleus density. This feature allows minerals not present in the chemical system to form according to kinetic rate laws by prescribing a minimum value for a supersaturated mineral's surface area over the calculation. For more information, please refer to section 4.2.4 Nucleation in the GWB Reaction Modeling User guide.

Hope this helps,

Jia Wang