Simulation of Aliquot extraction, followed by volume replacement

[peterwadeuk]

Greetings, good persons.

I am trying to simulate an experiment conducted by a colleage, and to use a British phrase, it is "doin' my 'ed in".

I would appreciate any help with the REACTION steps, and if my mangled pqi file is required, I will send it.

The situation is as follows:

1 g of rock powder (50 wt% Diopside; 30 wt% Forsterite) is introduced into a flask, and 45 mL simulated rainwater is added to the flask. The solid to liquid ratio is 22.2 g/L. The flask is stirred for 1 week, during which some of the rock minerals kinetically dissolve into the supernatant solution. After this period, 15 mL of supernatant aqueous solution is removed, and replaced by 15 mL of the simulated rainwater, which dilutes the aqueous solution. The flask is then stirred for a week, with further kinetic dissolution, 15 mL aqueous solution is removed and replaced with 15 mL simulated rainwater. The flask is now stirred for another two weeks, and on the 4th week of the experiment, 15 mL aqueous solution is once again removed and replaced with 15 mL simulated rainwater.

[dlparkhurst]

Maybe something like this. I'm using the database Kinec_v3.dat for the rate definitions. The second parameter of each kinetic reaction is the surface area, which is basically an adjustable parameter. SOLUTION_MIX is basically the same as MIX, but does not produce a calculation in the output.

Code: [Select]

SOLUTION 1-2
pH 7 charge
C(4) 1 CO2(g) -3.4
USER_PRINT
10 PRINT "Diopside, moles:   ", 1*0.5/GFW(PHASE_FORMULA("Diopside"))
20 PRINT "Forsterite, moles: ", 1*0.3/GFW(PHASE_FORMULA("Forsterite"))
END
PRINT
-user_print false
END
SOLUTION_MIX 1
1 0.045
END
KINETICS 1
Diopside
-m 2.3093e-03
-parms 0 0.1 0 0
Forsterite
-m 2.1326e-03
-parms 0 0.1 0 0
END
USER_GRAPH 1
    -headings               time SI_Diopside SI_Forsterite Delta_Diopside Delta_Forsterite
    -axis_titles            "Time, weeks" "Saturation index" ""
    -initial_solutions      false
    -connect_simulations    true
    -plot_concentration_vs  x
  -start
10 GRAPH_X TOTAL_TIME / 604800
20 GRAPH_Y SI("Diopside"), SI("Forsterite")
30 GRAPH_SY KIN_DELTA("Diopside"), KIN_DELTA("Forsterite")
  -end
    -active                 true
RUN_CELLS
    -cells 1
    -time_step    604800 in 10 #seconds # 1 week
END
SOLUTION_MIX 1
1 0.030
2 0.015
END
RUN_CELLS
-cells 1
-time_step 604800
END
SOLUTION_MIX 1
1 0.030
2 0.015
END
RUN_CELLS
-cells 1
-time_step 1209600
END
SOLUTION_MIX 1
1 0.030
2 0.015
END