Calculation of the heat of solution of HF
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This post was last edited by huanglei on 2023-6-28 21:46. Previously, I saw a thread on the forum discussing the enthalpy of dissolution of NaOH in water; ASPEN software is used to calculate the enthalpy of dissolution of NaOH – Serving 200 million industrial professionals – Powered by Discuz! (hcbbs.com). I believe it’s possible to manually calculate the enthalpy of dissolution using the parameter tables provided by Aspen, just as mentioned in that previous thread; and I have confirmed that it indeed works. It mainly involves calculations among parameters such as DHFORM, DHAQHG, and DHAQFM; of course, this is related to the degree of ionization of NaOH ； But recently, when there was a need to modify the heat of solution of a substance (an inorganic acid) in water, research was initiated on the heat of solution of HF in water in order to understand how the software performs such calculations. But using a calculation method similar to that for the heat of solution of NaOH, it was impossible to understand how Aspen arrived at its results Is there any teacher who is familiar with this area? I would appreciate some guidance! The following is the list of parameters built into Aspen ； When setting up a \"mixer + heat exchanger\" process in the Aspen software to determine the heat load of the heat exchanger, the calculated values are as follows: the heat of solution for HF is 36,080 kJ/kmol (when the molar ratio of HF:H2O is 1:100); it is 37,286 kJ/kmol (when the molar ratio is 1:10); and it is 39,581 kJ/kmol (when the molar ratio is 1:1). The differences among these three cases are likely due to varying degrees of ionization. Please discuss, thank you.
The principle behind Aspen software for calculating heat of solution is based on thermodynamic theory and experimental data. For the heat of dissolution of HF in water, Aspen performs calculations based on the physical property parameters of HF and H2O, as well as certain thermodynamic data. Specifically, Aspen uses the molar ratio of HF to H2O to calculate the heat of solution. According to the provided data, when HF:H2O=1:100, the heat of solution is 36080 kJ/kmol ； When HF:H2O=1:10, the heat of solution is 37286 kJ/kmol ； When HF:H2O=1:1, the heat of solution is 39581 kJ/kmol. During the calculation process, Aspen may use certain thermodynamic models or parameters to estimate the energy changes during the mixing process. These models and parameters are derived from experimental data and theoretical calculations. However, the specific calculation process is known only to the developers of the Aspen software; it may also involve certain calculation details and adjustments. In general, the Aspen software can calculate the heat of solution of HF in water based on the provided physical property parameters and calculation methods. Due to the influence of various factors such as the degree of ionization of the substance, temperature, pressure, etc., the heat of solution varies under different conditions. .
It is as you said; as you mentioned, the calculation logic of the software isn’t very clear, and I couldn’t find any answers by looking through the help documents.