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Marek Svab

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About Marek Svab

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  1. Hi Tom, thanks for fast response. Yes, it is clear... and simple reason.... But I would like to ask you ... even the curve is ok now...: Look at the text output (I studied only text output before, this is also why I missed the reaction rate...). I enclose one part (after 60 days): moles moles grams cm3 Reactants remaining reacted reacted reacted ---------------------------------------------------------------------------- Zincite 0.001873 -0.001873 -0.1524 Kinetic rate const. sp. surface net surface rxn rate mineral rxns (mol/cm2 s)* area (cm2/g) area (cm2) (mol/kg sec) ---------------------------------------------------------------------------- Zincite 1.000e-014 80.00 12.19 -2.814e-011 *Units in absence of promoting or inhibiting species. No minerals in system. ----------------------------------------------- What does it mean, that "moles remaining" is the same like "- moles reacted". Perhaps it only expresses some simple fact that zincite is precepitating toward equilibrium. However, It is not absolutely clear to me... (onoly from about 70 % ). Is it so that "moles remaining" means in our case "zincite already in the system", while "moles reacted" means "zincite precipotated till this time" - this is why the numbers are equal (-). Also - why there is mark "no minerals in system" - when zincite is already preciptated (even not to equilibrium amount). May be it has some principal/software reasons, but now it is, in my opinion, a bit confusing, isn't it? Many thanks! Marek.
  2. Dear GWB team, I am still learning how to effectively work with the GWB system. Now I was trying to deal with some kinetic effect. I started with simplest possible task (only for my understanding of the program). I wanted to calculate precipitation/dissolution of zincite. When I placed (in react) zincite as kinetic reactant, set surface area and kinetic constant, it was ok - I obtained desired curve in time (how zincite precipitated during the time). However, I prefer possibility of inclusion of kinetic effect onto species presented in the basis (or created by some reactions later in X1t). For this purpose I prepared script enclosed to this message (you have to use the thermodataset "thermo.com.v8.r6+.dat"). The task is simple - we have 2000 mg/kg of zinc in solution with pH 8. It is clear zincite is supposed to precipitate under such conditions, only zincite is allowed as mineral. Without kinetic, zincite is precipitated. But when kinetic was included (the same parameters which were working correctly in my previous task, only nucleus density was added because there was no mineral in the system at the beginning), the results were absolutely non-understandable. Please look at the results of the enslosed script. React correctly predicts zincite as mineral for precipitation (0.00193 moles - ok), includes it as kinetic reactant, but it also immediatelly writes that the same amount of zincite already reacted (at the first kinetic result). This situation remain the same within entire time period. This is why that no meaningful results were obtained. I was trying to find what is the problem for several hours, but I really do not know what to do with this. I was trying also various changes in the script, but without success. Since I want to work with the kinetic effects in the future, I must understand such simple tasks first. Could you help me with this? Thank you! Best regards, Marek Svab precipitation_of_zincite.rea
  3. Error in program X1t?

    Dear GWB team, I started to deal with one simple task in X1t and I found one inconvenient problem. If I open "medium properties" dialogue window and choose "porosity --> node by node" and than insert the porosity values for all nodes separately in the prepared dialogue, than, after closing the main dialogue "medium properties", it is not possible to open it again... Only way is to write on the command panel 'porosity = number %' - then it is possible to open the dialogue again (however with uniform porosity ...). Is it a mistake in program x1t or there is some reasons for this behavior - i see no reason for this inconvenient user behavior. I tried it with different values and it was ok. It seems there is a problem with my particular task. I attach the script - if I open it in X1t - it is not possible to open the mentioned dialogue.Why? Thank you for the response. Marek Svab stopova___kolona_jemn___p__sek__1_.x1t
  4. Transport modelling (sorption) - breakthrough curves

    Geoffrey, thank you for your response. However, I have to say I am not much sastisfied with your answer. Of course, If you increase exchange capacity, you delay breakthrough of sorbate through layer. It is nothing surprising and shape of the curves inside of layer before breakthrough is ok also in my contribution. Finally, you only showed me, how it can be delayed (this is what I was playing with a lot). In your picture, it is not breakthrough. I agree, it is ok. But my question related to breakthrough situation, where the shape of the curves is not correct, I think. Please, read my first contribution carefully. Could you really try to explain me such behaviour of the breakthrough curves? I believe the situation is deeply described in first contribution. Many thanks. Also, could you, my be, give me contact on somebody who would be better for such type of problem? Looking forward on your answer. Have a nice day! Regards, Marek Svab
  5. Dear GWB team, I would like to share with you our results of transprt modelling, which are hard for me to explain. I do not know if I do something wrongly or if there i some other mistake or problem. I wanted to calculate the sorption filter 100x100x200 cm filled by sawdust. Sorbed substance is naphthalene. A attach script, compressed thermodataset (extended by naphthalene by us), dataset with langmuir data and two figures - outputs from calculation including my drawing. Thus, you can look directly at the results and if you would like to, also re-calculate our task. Let describe the problem. Looking on the Figure 1 (concentration profile of naphthalene within the layer during the time): my opinion is that shape of the last two curves (right side) should be as I marked it by blue dots. Simply, the shape of the curves should not substantially change except its termination with the end of the layer. I see no reason why the curves should change their shape at the end of the layer, especially when boundary condition is set on "outlet" on the right side. Looking on the figure 2 (concentrations of naphthalene in various positions at the layer during the time): again the shape of the breakthrough curve (in the last node - last curve on right side) differs from shape of other curves. Why? It is obvious that the sheerer shape of the curve starts just at the end of the layer (it is clear also from the figure 1 - if we think about it). It seems, that there is other source of adsorbate at the end of layer, but boundary condition is "outlet" - it should be ok. Furthermore, the breakthrough curve (right curve in the figure 2) is "unreal". Its shape should be similar to for example first two curves in the same figure. I was playing a lot with this, but I can not explain it and I have no idea what to do with this problem. Finally, I found similar problem also in frame of other sorption calculations (advanced sorption modelling), I added these results because they are simplest for disclosing here. I would be very glad to have an advice what is wrong. I really think that shapes of curves are incorrect, but if you explained me if its correct, I will be glad. Thank you! Marek Svab, Dekonta,a.s. thermo.com.v8.r6__MS_KS_PRB_v2.zip sorption_example_svab.x1t Langmuir_piliny.zip
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