I'm working on a problem using an approach that is similar to the one described by Kyle. In my flush model, however, I wish to fix aqueous CO2 activity to simulate buffering by a separate supercritical CO2 phase. I'm running into a brick wall with this. My latest and greatest attempt was to revise the database by adding a fictive supercritical CO2 phase as a mineral, but this approach yields multiple mass imbalance errors for minerals, aqueous species, and gasses. I'd be curious to hear what folks think. I've attached two input files that I've developed, one to equilibrate a groundwater with CO2 and a second to flush this water through a rock.
Thank you
John
Kaszuba input-equilibrate with CO2.rea
Kaszuba input-flush model.rea