Issues with the PRO2 simulation cycle process
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I used Pro2 to simulate a very large loop, and when the last stream was supposed to merge with an originally designated stream, a problem arose. By adjusting the parameters, the temperature and flow rate of the last stream became quite similar to those of the stream it was meant to merge with, and convergence was achieved when I clicked to start the simulation. But when I click to run it again, the temperature and flow rate of the combined logistics change once more. What is the reason for this? ?
This situation is very common in iterative processes; it is recommended to split the logistics, assign values, and then perform iterative calculations
Do you mean: using a logistics configuration with a fixed composition in place of a cyclic logistics system, thereby eliminating the large cycles; after convergence, iterating the resulting configuration to obtain a fixed logistics setup? This is a very good method for solving convergence problems in the presence of relatively complex loops. Do anyone else have any better ideas?
Assigning initial values to logistics makes it easier to converge to the desired point.
“Do you mean: using a logistics configuration with a fixed composition in place of a cyclic logistics system, thereby eliminating the large cycles; after convergence, iterating the resulting configuration to obtain a fixed logistics setup? ” This large cycle still exists; it’s just that initial values are assigned to the logistics, as well as to the components that make up the flow rate
I’m not quite sure what the original poster means – does the result change after it’s run? Have the flow rate parameters changed significantly? When simulating the cyclic process, such as the circulation of the absorbent in the absorption tower and desorption tower systems, an adequate amount of fresh absorbent can be added to the top of the absorption tower at the beginning. All the absorbent at the bottom of the desorption tower is discharged. Once the parameters are adjusted to the appropriate values, a splitter is added at the end of the absorbent stream at the bottom of the desorption tower: a small portion of this stream is directed to the top of the absorption tower for circulation, while the larger portion is discharged. As stability is achieved, the amount of material in circulation is gradually increased. Once the process is satisfactory, some key parameters of each device should be recorded to modify the initial values, so that the simulated process remains more stable.
Are the logistics pressures and composition upon your return exactly the same as those of the initial logistics? You might also try using the method from floor 7.
It’s actually not stable either, especially in the case of chemical absorption – there is always a chemical equilibrium at play. As a result, there are many different ions present, and even if a certain component is added, it’s difficult to achieve an exactly identical composition. This makes it hard to establish a stable cycle, and errors keep occurring... It’s indeed quite problematic.