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*To*: <dlpark@xxxxxxxx>*Subject*: modelling a stirred tank reactor*From*: "Stephan Kohler" <skohler@xxxxxxxxxxxxxxxx>*Date*: Thu, 28 Nov 2002 14:18:06 +0100*Importance*: Normal

Dear Sir, i am using the Phreeqc program to model batch dissolution experiments and speciation of aqueous equilibria. I would appreciate if you could have either yourself or on of your students could have a look into the following problem : My real interest lies in modelling open stirred tank reactors to simulate flow through dissolution experiments. I started with the idea to do several iterations of a loop that would contain both a kinetic rate and a mixing operation of the solution resulting from the dissolution and a predefined "inlet" solution which would mix at constant volume ratios. I did not get this to work as a mixing function (MIX) may not be part of a rate (KINETICS) function. Now in theory I could do sequential steps of rate,mixing rate,mixing rate,mixing. Now while this does not appeal to me from a programming viewpoint (it seems akward !) I stumbled into a larger problem. I can recover the solution compositon by adding several PUT commands for all necessary ions but how do I then explain PHREEQC to use these to define a new solution that will subsequently be used in a KINETICS block. The following schematic script showing two iterations did not work ! > ************************************************************************** > > TITLE > Solution 1 > Solution 2 > MIX Solution 1 0.2 > Solution 2 0.8 > Save Solution 3 > Use Solution 3 > KINETIC blabla > RATE blabla > -start > ..... > x=MOL("Ca2+") > PUT(x,1) > -end > Solution 4 THIS IS THE CRUCIAL OPERATION !!! > Ca GET(1) > MIX > solution 1 0.2 > solution 4 0.8 > END > Save Solution 5 > USER_PUNCH > .... > Use Solution 5 > KINETIC blabla > RATE blabla > -start > ..... > x=MOL("Ca2+") > PUT(x,1) > -end > Solution 6 > Ca GET(1) THIS IS THE CRUCIAL OPERATION !!! > MIX > solution 6 0.2 > solution 3 0.8 > END > Save Solution 7 > USER_PUNCH > .... > END > > ************************************************************************** Now are there more elegant ways to do it ? How can I define a new solution from previously stored parameters OUTSIDE a rate function ? Can one make a DO LOOP to group a MIX and RATE function with kind regards Stephan Kohler """"""""""""""""""""""""""""""""""""""""""""""""""""" Stephan Köhler LMTG - UMR CNRS n°5563 Observatoire Midi-Pyrénées Université Paul-Sabatier 38, rue des 36-Ponts 31400 Toulouse TEL + 33(0) 561557611 FAX + 33(0) 561558138 """""""""""""""""""""""""""""""""""""""""""""""""""""

**Follow-Ups**:**Re: modelling a stirred tank reactor***From:*David L Parkhurst

**Re: Modelling saine environments***From:*h2osoft

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