In the attached sim file I am accessing wet Cl2 streams cooling loads: case A where it has no O2 & case B where it has 0.05 (mole fraction) O2. All other conditions are same because case A was copied to produce case B. I cannot infer the results & require someone to look at the cooler load (in KW) because they seem highly influenced with minor O2 in material stream to cooler! I have checked Cp values & density values ....they don't differ much
My 2nd query is that dewpoint temperature of material stream Cool-Wet-Cl2 is shown erratic in Material Stream tab as well as when exported to Spreadsheet as variable. To resolve this I have to create a lone stream as is shown in attachment
My 3rd query regarding the same attachment is that I want to setup a sensitivity analysis such that in feed Wet-Cl2 material stream I have simaltaneously an increase of 0 to 0.05 O2 (mole fraction) as well as decrease of 0.2 to 0.15 H2O (mole fraction) ...such that overall mole fraction remains 1. If this can be done I could have skipped copying case A as case B
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1 - I don't see anything wrong with the calculations, you've added O2 and that changed the vaporized fractions, which led to a change on the overall stream enthalpy and to the heat load as a consequence.
2 - If you enable calculation of bubble and dew points in the flash algorithm settings, the calculated dew points will be the same. it is not enabled by default because it is an expensive calculation, and can lead to unmeaningful values on some streams.
3 - You can use a python script to do that very easily. Let me know if you need help.
Regards
Daniel
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
In the attached sim file I am accessing wet Cl2 streams cooling loads: case A where it has no O2 & case B where it has 0.05 (mole fraction) O2. All other conditions are same because case A was copied to produce case B. I cannot infer the results & require someone to look at the cooler load (in KW) because they seem highly influenced with minor O2 in material stream to cooler! I have checked Cp values & density values ....they don't differ much
My 2nd query is that dewpoint temperature of material stream Cool-Wet-Cl2 is shown erratic in Material Stream tab as well as when exported to Spreadsheet as variable. To resolve this I have to create a lone stream as is shown in attachment
My 3rd query regarding the same attachment is that I want to setup a sensitivity analysis such that in feed Wet-Cl2 material stream I have simaltaneously an increase of 0 to 0.05 O2 (mole fraction) as well as decrease of 0.2 to 0.15 H2O (mole fraction) ...such that overall mole fraction remains 1. If this can be done I could have skipped copying case A as case B
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1 - I don't see anything wrong with the calculations, you've added O2 and that changed the vaporized fractions, which led to a change on the overall stream enthalpy and to the heat load as a consequence.
2 - If you enable calculation of bubble and dew points in the flash algorithm settings, the calculated dew points will be the same. it is not enabled by default because it is an expensive calculation, and can lead to unmeaningful values on some streams.
3 - You can use a python script to do that very easily. Let me know if you need help.
Regards
Daniel
Daniel if your time does allow you please do attach a python script & if it can be done via VBA (a sample will suffice) I would stop bothering you :)
Sure. :-)
I've imagined something like the following... of course you can adapt it for your specific needs:
ms = Flowsheet.GetFlowsheetSimulationObject('Wet-Cl2') ms2 = Flowsheet.GetFlowsheetSimulationObject('Dry-Cl2') xO2 = 0.0 xH2O = 0.2 delta = 0.01 for i in range(0, 10): xO2 += delta xH2O -= delta xCl2 = 1 - xO2 - xH2O ms.Phases[0].Compounds['Oxygen'].MoleFraction = xO2 ms.Phases[0].Compounds['Water'].MoleFraction = xH2O ms.Phases[0].Compounds['Chlorine'].MoleFraction = xCl2 Flowsheet.RequestCalculation() print(str(ms2.Phases[0].Properties.massflow))You can do it with VBA but it is much faster and productive if you use DWSIM's own Script Editor. Python is such an easy language to use... I love it.