Some confusions in Aspen Plus?
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I’m encountering some problems in Aspen Plus: 1. What is heat duty in the unit operation models of Aspen Plus? How to calculate or how to look it up? 2. The user manual mentions power-law equilibrium reactions and reactions involving flow rate control in the context of chemistry; could a professional please explain what these terms mean? 3. When selecting a mode inside the cyclone separator, there are the design and simulation modes; according to the user manual, they seem to correspond to design calculations and analysis calculations. In what areas are these two types of calculations used respectively? For general gas-solid separation, should design calculations be used or estimation calculations? Also, what value should be set for the minimum no. of cyclones in the design parameters? (Note: Cyclone separators are mainly used to separate fly ash from gas.) Please help answer this question; thank you!
Heat duty is the heat load. It is calculated by default during the logistics calculation process. It can also be searched for separately in the property settings. I’m not sure about what comes after that.
In the third question, within the simulation model, the cyclone’s separation efficiency and pressure drop are calculated based on the cyclone separator diameter specified by the user. In the design model, the geometric structure is calculated to achieve the separation efficiency and maximum pressure drop specified by the user. This has been understood, but what value should be set for the maximum no. of cyclones in the design parameters? When I ran the simulations, I received more than 100 warnings such as: * WARNING: EFFICIENCY IS TOO LOW; THE DIAMETER IS SET TO THE MINIMUM VALUE, AND A CYCLONE WITH HIGH EFFICIENCY IS REQUIRED. * WARNING: NO SOLUTION IS POSSIBLE. THE NUMBER OF CYCLONES HAS BEEN SET TO 100. * WARNING: THE INLET VELOCITY IS HIGHER THAN THE ALLOWED LIMIT OF 30 M/S; THE INLET GAS VELOCITY IS 188 M/S. THE RATIO OF THE INLET VELOCITY TO THE SALTATION VELOCITY IS 1.63, WHICH IS GREATER THAN 1.36, SO SOLID REENTRANCE MAY OCCUR. What should I do regarding these warnings? Could it be that there’s an issue with my input data? Please help me.
I haven’t used ASPEN to calculate cyclone separators, but from the warnings it seems that your feed rate is too high and the diameter of the separator is too small, resulting in inadequate separation performance. The velocity at the inlet of the cyclone separator is also too high, and the pressure drop appears to be excessive as well. Please upload your simulation files for more details.
I also noticed that the flow rate at the inlet was too high; it seems that by default the inlet flow rate should not exceed 30 m/s, but mine was too high. By using user-defined settings, I was able to obtain accurate simulation results. There’s one thing I’m not quite sure about: in the simulation model, the separation efficiency and pressure drop are calculated based on the diameter of the cyclone separator specified by the user. In the design model, the geometric structure is calculated to achieve the separation efficiency and maximum pressure drop specified by the user. Is it necessary to calculate using the methods provided in the user guide and enter the results into the design model, or is there some other explanation? I don’t quite understand this sentence. Please ask the moderator upstairs for guidance.
Heat duty refers to the heat load; it should be available in the profile file of the block
The problem isn’t solved yet; take it on yourself so that the post doesn’t get buried. The user manual discusses power-law equilibrium reactions and reactions involving flow rate control in the context of chemistry. Could someone explain these two types of reactions? Additionally, in the simulation model, the separation efficiency and pressure drop of the cyclone are calculated based on the cyclone diameter specified by the user. In the design model, the geometric structure is calculated to achieve the separation efficiency and maximum pressure drop specified by the user. Is it necessary to calculate using the methods provided in the user guide and enter the results into the design model, or is there some other explanation? Waiting online for guidance!
I majored in reaction engineering, and I’ve long noticed that the Chinese translation of the Aspen manual is unprofessional – it’s clearly the work of machine translation. I suspect the intended meaning of “reaction with flow rate control” is “reaction with rate control””
According to the hints, the diameter of the cyclone selected is too small, resulting in excessively high efficiency; the gas velocity is 188 m/s, which exceeds the erosion speed (that is, exceeding this speed will lead to erosion corrosion). It is recommended that the gas velocity not exceed this value； Also, the number of cyclones should preferably not exceed 10.
The problem with this cyclone separator is really frustrating. 1. The separator provided by the cyclone is far too different from the actual situation. The maximum diameter in the module is only 5m, and it’s unknown how many separators will be used. It’s fine as long as it’s roughly the same as the actual number in use. 2. The information provided in the manual and modules is too limited, which is really frustrating. In summary, the diameter of cyclone separators these days is around 8 meters, whereas those available offer a maximum diameter of only 5 meters. Therefore, the separators used in simulations cannot be chosen based on actual requirements; instead, one must select and adjust the parameters in the simulation according to the separation efficiency required in practice, so as to achieve the desired efficiency. . . There’s nothing else to do. . . 3. If that expert has any new insights, please come forward and share them. . . . Thank you so much. . .
Hey classmate, have you managed to solve your problem? I’m facing the same issue – how can I resolve it? ? ? ? Looking forward to a reply, thank you!