I have some doubts regarding the calculation of reboilers using HTFS; please advise
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I’ve been recently studying the structural dimensions of *computational reboilers, using Mtrebsys in HTFS. I’ve encountered the following issues; I would be extremely grateful if someone could provide some guidance! I can be considered a multi-component mixture, and all property data were calculated using ASPEN. However, when filling out form 312, it is required to enter the value corresponding to a specific temperature or the heat increment on the evaporation curve. Which data should be used in Aspen? Should it be the HMX or DMX value at that temperature point, or should some other method such as heat load be employed for the calculation? When I did the calculations, I used the HMX value for the 312 card; I also used the value obtained from heat load calculations. When fitting the HTFS curve, 84.4 was found to be the bubble point temperature, while 85.6 was the dew point temperature. The final calculations yielded results consistent with those obtained using Aspen, but the exit temperature calculated in this approach was 84 degrees, which is lower than the bubble point temperature. How is it possible to obtain a value indicating an increase in evaporation when the temperature is below the bubble point temperature? :(
It’s caused by the pressure difference! When calculating the bubble point and dew point temperatures, you are working with values at a certain pressure; however, in actual calculations, the pressure difference is taken into account, the outlet pressure decreases, and as a result, the bubble point also decreases. That’s why the phenomenon you mentioned occurred!
I encountered a similar problem before; I was puzzled for a long time until I discovered what the friend upstairs had mentioned. The friend upstairs really has a strong understanding ability; I’ve read the original poster’s question many times yet still don’t understand what it means. I understand it only now