reaction path calculation details

[jack]

Hi:

Perhaps this is a very simple question but if run a reaction path simulation with the flush option using only simple tracers..why does it take more than one reacted fluid volume for the composition to change from solution A to solution B ?

For example in this file minerals, sorption, and redox are all suppressed and i am basically displacing a fluid with pH 5.4 by one with pH 3.334. Why does it take more than 1 kg reacted H2O mass for the pH to reach 3.334 ? (it takes almost 4 kg). Any ideas ?

 

temperature = 20.4

decouple ALL

H2O = 1 free kg

pH = 5.4

Na+ = 1 umolal

Cl- = 1 umolal

balance on Cl-

reactants times 10

react 1 kg of H2O

react .000463 mol of H+

react 2.16e-11 mol of OH-

react 1 umol of Na+

react 1 umol of Cl-

 

suppress ALL

flush

plot = character

delxi = 1 linear

epsilon = 5e-11

[Tom Meuzelaar]

Hi Jack:

 

When I look at the plot results for your script, it appears that the pH drops to 3.5 after the addition of 1 kg of fluid, correctly mimicking the flush configuration.

 

Do you see something different?

 

Regards,

 

Tom Meuzelaar

RockWare, Inc.