Click here to donate to keep PhreeqcUsers open
Welcome,
Guest
. Please
login
or
register
.
Did you miss your
activation email
?
1 Hour
1 Day
1 Week
1 Month
Forever
Login with username, password and session length
Forum Home
Login
Register
PhreeqcUsers Discussion Forum
»
Beginners
»
PHREEQC basics
»
Simulation of Aeration in PHREEQC and Using Reactants
« previous
next »
Print
Pages: [
1
]
Go Down
Author
Topic: Simulation of Aeration in PHREEQC and Using Reactants (Read 320 times)
Onur
Contributor
Posts: 9
Simulation of Aeration in PHREEQC and Using Reactants
«
on:
May 23, 2022, 12:34:09 AM »
Hello everyone, I am trying to model a high-density sludge mine water treatment plant. I have two question about simulation:
1. In the first reactor, mine water is aerated (with 300 L/min) and also H2O2 is added to the reactor. How can I simulate this in PHREEQC after mine water data input?
2. I want to simulate the alkaline reagent addition by using REACTION keyword. The thermodynamic features of some alkaline agents such as NaOH and oxidizer H2O2 is not available in the databases. Does it affect the result a lot if I use them in my simulation or would it be better to find their log K values and add them to the database before using them?
Thanks in advance for your time.
Logged
dlparkhurst
Top Contributor
Posts: 2736
Re: Simulation of Aeration in PHREEQC and Using Reactants
«
Reply #1 on:
May 23, 2022, 02:52:05 PM »
Let's assume you define your solution with SOLUTION, and then add a reaction step.
The simplest approach for aeration is to add O2(g) as EQUILIBRIUM_PHASES; O2(g) -0.7 10. This will add enough dissolved O2 to be in equilibrium with the atmosphere. However, it will oxidize any reduced dissolved constituents such as Fe(2), N(-3), S(-2), etc. More complicated would be to use KINETICS to oxidize organic carbon and other reduced constituents kinetically.
You can simply add H2O2 in REACTION. In the reacted solution, the effect of adding 1 mole of H2O2 will be equivalent to adding 0.5 mole of O2. Even if you had thermodynamic data for H2O2(aq), it will be unstable relative to dissolved oxygen. Of course, dissolved oxygen will react with other reduced constituents.
As for NaOH, I think you want to add it through REACTION rather than any equilibrium condition.
Logged
Onur
Contributor
Posts: 9
Re: Simulation of Aeration in PHREEQC and Using Reactants
«
Reply #2 on:
May 23, 2022, 04:24:36 PM »
Hello Sir, thanks for your answer. For aeration should I also add the CO2(g) -3.5 in the equilibrium phases (since the reactors are open to the atmosphere) or O2(g) would be enough? Also, they are adding the H2O2 in the same reactor. So if I had added oxygen as reactant and O2(g) to the input script, would it have been the same as it had not been added? (since added oxygen by H2O2 will eventually reach the equilibrium phase.
Best regards
Logged
dlparkhurst
Top Contributor
Posts: 2736
Re: Simulation of Aeration in PHREEQC and Using Reactants
«
Reply #3 on:
May 23, 2022, 06:04:13 PM »
In theory, you would include CO2(g) in EQUILIBRIUM_PHASES in addition to O2(g). However, I'm not sure it would happen in practice. Theoretically, you would convert almost all of the Dissolved Inorganic Carbon to CO2, which would outgas leaving a very high pH. If you have data from the process, you can calculate what the P(CO2) from pH and alkalinity to see if atmospheric CO2 is reasonable.
Yes, I think adding H2O2 in REACTION with O2(g) in EQUILIBRIUM_PHASES would produce the same solution composition, regardless of the amount of H2O2 added. (Let me know if that is wrong.)
Logged
Onur
Contributor
Posts: 9
Re: Simulation of Aeration in PHREEQC and Using Reactants
«
Reply #4 on:
May 25, 2022, 08:55:37 PM »
Hello sir, thanks for your answers and your time. Yes, as you said, adding H2O2 while equilibrating the system in terms of O2 does not change the O2 content in the solution.
Logged
Print
Pages: [
1
]
Go Up
« previous
next »
PhreeqcUsers Discussion Forum
»
Beginners
»
PHREEQC basics
»
Simulation of Aeration in PHREEQC and Using Reactants