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Data in kinetic reactions
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Topic: Data in kinetic reactions (Read 710 times)
AliMahaqi
Contributor
Posts: 3
Data in kinetic reactions
«
on:
July 14, 2023, 04:21:25 AM »
Hi,
I am a pretty new PHREEQC user and got a bit confused. I just want to know when I want to run a kinetic simulation, the data in the Rates section where did they come from? There are lots of lines with different numbers and words! Do those data come from Palandri and Kharaka? or any references? It would be a great help to help me to find out the sources/patterns of those data.
Example (Taken from Groundwater Geochemistry by Broder J. Merkel · Britta Planer-Friedrich
SOLUTION 1 distilled water
pH 7
temp 10
EQUILIBRIUM_PHASES
CO2(g) -3.5
KINETICS 1
Calcite
-tol 1e-8
-m0 3e-3
-m 3e-3
-parms 50 0.6
-steps 36000 in 20 steps // 36.000 seconds*
-step_divide 10000 // first interval calculated with 3.6 sec.*
RATES
Calcite
-start
1 rem Calcite solution kinetics according to Plummer et. al 1978
2 rem parm(1) = A/V, 1/dm parm(2) = exponent for m/m0
10 si_cc = si("Calcite")
20 if (m <= 0 and si_cc < 0) then go to 200
30 k1 = 10^(0.198 - 444.0/(273.16 + tc) )
40 k2 = 10^(2.84 - 2177.0/(273.16 + tc) )
50 if tc <= 25 then k3 = 10^(-5.86 - 317.0/(273.16 + tc) )
60 if tc > 25 then k3 = 10^(-1.1 - 1737.0/(273.16 + tc) )
70 t = 1
80 if m0 > 0 then t = m/m0
90 if t = 0 then t = 1
100 moles = parm(1) * 0.1 * (t)^parm(2)
110 moles = moles * (k1 * act("H+") + k2 * act("CO2") + k3 * act("H2O"))
120 moles = moles * (1 - 10^(2/3*si_cc))
130 moles = moles * time //this line is a ”must“ for each BASIC-program*
140 if (moles > m) then moles = m
150 if (moles >= 0) then goto 200
160 temp = tot("Ca")
170 mc = tot("C(4)")
180 if mc < temp then temp = mc
190 if -moles > temp then moles = -temp
200 save moles //this line is a “must” for each BASIC-program*
-end
SELECTED_OUTPUT
-file 4_Calcite.csv
-saturation_indices calcite
end
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dlparkhurst
Top Contributor
Posts: 3585
Re: Data in kinetic reactions
«
Reply #1 on:
July 14, 2023, 04:52:45 AM »
1 rem Calcite solution kinetics according to Plummer et. al 1978
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AliMahaqi
Contributor
Posts: 3
Re: Data in kinetic reactions
«
Reply #2 on:
July 16, 2023, 04:49:48 AM »
Thanks, David for your response.
My question is here, are the lines below Rate have a specific pattern? like this:
rem parm(1) = A/V, 1/dm parm(2) = exponent for m/m0
10 si_cc = si("Calcite")
20 if (m <= 0 and si_cc < 0) then go to 200
30 k1 = 10^(0.198 - 444.0/(273.16 + tc) )
40 k2 = 10^(2.84 - 2177.0/(273.16 + tc) )
50 if tc <= 25 then k3 = 10^(-5.86 - 317.0/(273.16 + tc) )
60 if tc > 25 then k3 = 10^(-1.1 - 1737.0/(273.16 + tc) )
70 t = 1
80 if m0 > 0 then t = m/m0
90 if t = 0 then t = 1
100 moles = parm(1) * 0.1 * (t)^parm(2)
110 moles = moles * (k1 * act("H+") + k2 * act("CO2") + k3 * act("H2O"))
120 moles = moles * (1 - 10^(2/3*si_cc))
130 moles = moles * time //this line is a ”must“ for each BASIC-program*
140 if (moles > m) then moles = m
150 if (moles >= 0) then goto 200
160 temp = tot("Ca")
170 mc = tot("C(4)")
180 if mc < temp then temp = mc
190 if -moles > temp then moles = -temp
200 save moles //this line is a “must” for each BASIC-program*
-end
And if yes, do we just need to replace the values in this pattern? or do we need to write this series of lines for every reaction?
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dlparkhurst
Top Contributor
Posts: 3585
Re: Data in kinetic reactions
«
Reply #3 on:
July 18, 2023, 01:28:40 AM »
The Plummer and others rate expression for calcite is different than the rate expressions for minerals in Palandri and Kharaka. The Plummer and others rate expresion is unique to a few carbonates studied by Plummer and coworkers.
Palandri and Kharaka use a rate expression that is common to all of the minerals that they consider. In using their rates, you use the same pattern, but you still need to write a script for each mineral.
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AliMahaqi
Contributor
Posts: 3
Re: Data in kinetic reactions
«
Reply #4 on:
July 21, 2023, 02:27:22 AM »
Thanks a bunch
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Kinetics and rate controlling factors
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Data in kinetic reactions