Aspen** boiling point data issue
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When searching for the azeotrope temperature of two components in the Aspen database, it is possible to find it sometimes, but not other times. For details, please refer to the bkp file of Aspen Plus V8.6 version (the file extension will be bkp after downloading). For example, the azeotopic temperature of valeraldehyde and water could previously be found to be around 86 degrees under the NRTL equation, but it can no longer be determined now. If the boiling points could be retrieved from the database before, why can’t they be retrieved now? I’m not sure whether it’s an issue with the settings in the properties or a bug in the software; I’d appreciate your advice! The azeotrope temperature can be found at: simulation - home - azeotropy search, then select water and pentanal.
Results calculated using different physical property methods vary. Different composition systems may yield different calculated results; in my view, this is due to the binary interaction parameters of the system
This post was last edited by jinjinaaaaaaaa on 2018-4-3 09:43. Thanks for the replies! I’m not sure which version of Plus you are using – is it the legitimate version or a cracked one? I’m using Plus v8.6, the cracked version; I also tried using the NRTL equation, but it still shows no azeotropes forming. I also tried using UNIFAC, and the azeotrope components differ significantly from those you found. 1. In multi-component systems, when searching for the azeotrope temperature of valeraldehyde and water separately, does the presence of other components affect the results? ； 2. Is there a huge difference between the cracked version and the legitimate one? . .
This post was last edited by jinjinaaaaaaaa on 2018-4-4 10:15. Could you please tell me where this data comes from? Is it reliable? I found a foreign literature study indicating that the solubility of 90-degree valeraldehyde in water is very low, at approximately 0.2% molar fraction; therefore, the VLL value is correct! However, since electrolytes are also involved in this system, if the property equation you mentioned is used, it will not be possible to simulate the electrolytes. Thank you!
In both cases, is the binary interaction parameter present? Please check.
I’ve seen it before; binary interaction parameters do exist. Later, I simulated the azeotropic distillation of valeraldehyde and water separately, and separation was achieved fairly well, with the composition of the overhead fraction being very close to that of the azeotic components. Upon adding PBA (2-propyl-2-heptenal), the composition at the tower top changed significantly, with the water content reaching nearly 85%, which is far from the azeotropic composition of water and valeraldehyde. PBA also shows no azeotropy with water or valeraldehyde. I would like to ask why this is the case. Thank you
This is a bug in the software