Mattm Posted April 15, 2021 Share Posted April 15, 2021 Hello, I'm putting a reactive transport model together in X1t. The aquifer I'm modeling contains carbonates, clays, and silicates. I'm utilizing custom kinetic rate laws which are sensitive to changes in pH. I have been trying to run simulations using kinetic constraints for all the minerals, but my model has been getting stuck and crashing and/or running incredibly slow. I have read that it is best to avoid simultaneously using kinetic constraints for minerals with greatly differing kinetic rates, and it is a better approach to instead set the more rapidly reacting minerals as equilibrium species. I'm wondering how I might do that? Does that mean I would just add the rapidly reacting minerals as "simple" minerals? Since the "simple" minerals are "added to the model over the course of the simulation", I'm not sure how I would approach setting their wt% values with respect to the single wt% value I have from XRD data. Likely, I am misunderstanding the meaning of the "simple" minerals. I'm also wondering, at what point do I draw the line? For example, I am including carbonates with reaction rates around 10^-5, chlorite with a reaction rate around 10^-12, anorthite with a reaction rate around 10^-14, and clays with reaction rates as low as ~10^-20 in basic conditions. I think I should be using equilibrium to model carbonate and perhaps chlorite dissolution, but between anorthite and the clays, I still have several orders of magnitude difference in their kinetic rates. I guess my question is at what difference in kinetic rate magnitude would you avoid utilizing kinetics. Thanks Quote Link to comment Share on other sites More sharing options...
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