How many interactions are necessary for one simulation?
Are you talking about the column iterations in the main data entry window when you first double click to open a column? If so, then it all depends on your model. Some processes may call for more iterations, while others might not need as many. The default within the software is 15 iterations, but it is often smart to increase this to anywhere between 30-50 iterations. Anything higher than that is usually not necessary and if the column is calculating more iterations than that, there are usually other issues with the column design that should be looked at and corrected.
The damping factor, how should be defined and what values are correct for one simulation? (have you one table for that?)
Damping factor values can range between 0.0 and 1.0. The damping factor limits the step size that the column’s algorithm takes when determining a new initial estimate for its calculations. A value of 1.0 means that it takes a full step size, while a value of 0.5 means that it only takes half of the full step size. This helps the column algorithm in converging problems due to oscillation and divergent behavior in the calculations. There are no set guidelines as to what damping factor value to use. It is trial and error to determine which is the best value to use. The first step you should take when determining whether or not to apply damping is to figure out if there is oscillation or divergence occurring in your column calculations. If there is not oscillation or divergence, then damping is probably not necessary and you should focus on other aspects of the column’s set up to fix convergence issues. If there is oscillation or divergence, you should start with a value of 0.9 and go down by increments of 0.1 to see if any value of the damping helps. If you achieve a solution by applying damping, you could try other values, but it does not mean that a lower value will give better results or easier convergence. A value of 0.6 could result in a solution, while a value of 0.4 could result in no solution. That’s why it’s trial and error to figure out what works best.
In the simulations I do of one column, I don´t know if for more or better separation can I considered the hydraulics of the column? I have used the simulations packages KG-TOWERS and Sulcol, the results are very different in comparison with the PRO/II results. (flooding factor, velocities in the plate, pressure drop, others)
If your column has packed sections or tray hydraulics that you need to consider, then yes, you will need to add tray hydraulics to your column to get a better representation of the behavior of the column. This may or may not result in better separation within the column. It’ll all depend on the case.
Damping factor values can range between 0.0 and 1.0. The damping factor limits the step size that the column’s algorithm takes when determining a new initial estimate for its calculations. A value of 1.0 means that it takes a full step size, while a value of 0.5 means that it only takes half of the full step size. This helps the column algorithm in converging problems due to oscillation and divergent behavior in the calculations. There are no set guidelines as to what damping factor value to use. It is trial and error to determine which is the best value to use. The first step you should take when determining whether or not to apply damping is to figure out if there is oscillation or divergence occurring in your column calculations. If there is not oscillation or divergence, then damping is probably not necessary and you should focus on other aspects of the column’s set up to fix convergence issues. If there is oscillation or divergence, you should start with a value of 0.9 and go down by increments of 0.1 to see if any value of the damping helps. If you achieve a solution by applying damping, you could try other values, but it does not mean that a lower value will give better results or easier convergence. A value of 0.6 could result in a solution, while a value of 0.4 could result in no solution. That’s why it’s trial and error to figure out what works best.
In the simulations I do of one column, I don´t know if for more or better separation can I considered the hydraulics of the column? I have used the simulations packages KG-TOWERS and Sulcol, the results are very different in comparison with the PRO/II results. (flooding factor, velocities in the plate, pressure drop, others)
If your column has packed sections or tray hydraulics that you need to consider, then yes, you will need to add tray hydraulics to your column to get a better representation of the behavior of the column. This may or may not result in better separation within the column. It’ll all depend on the case.
The hydraulics, is it very significant in simulation of a column?
Tray hydraulics are only significant if you need to take the hydraulic calculations into consideration. Otherwise, if you are only looking to achieve a specific separation, you could probably not use them and design the column to achieve your main separation goals. It all comes down to what’s most important for you and what it is that you are trying to accomplish with your column and your model.
I know the important to the thermodynamics and the feed composition, but do you don´t have any tips or simulation troubleshooting for the moment to do simulation of distillation columns?
I’m not exactly sure what you’re asking. Are you asking for thermodynamic tips for distillation columns? If so, it’s all going to depend on the process. With any unit operation (distillation column or not), your choice of thermodynamic method comes down to a few factors –
i. What components do you have?
ii. What compositions do you have of these components?
iii. What’s your operating temperature and pressure?
Those factors determine which thermo method is best suited for your process. You can get more thermo recommendations by going to our thermodynamic reference manual. That is accessed by going to Help à Reference Manual from within PRO/II, then selecting “Volume I: Component Data and Thermodynamic Methods”. You could also call your local tech support hotline for advice. To find your local office, click here
Theoretical tray efficiency recommended for Invensys? Do you have some paper, table or similar?
Tray efficiencies are not necessary in PRO/II unless you are using the actual amount of trays for your column. If you have already converted your column to a theoretical number of trays and are using that value as the number of trays for the column, then you have already taken into consideration any efficiencies you may have.
The algorithm used for default is good, but depending for the evaluate case, some recommended for this cases
There are several algorithms available to you within the column. The default is Inside-Out. This is a very good algorithm because it is widely applicable to both mechanically complex columns as well as thermodynamically complex columns, it’s forgiving of bad initial estimates, and it solves very fast. This method does not take into account free water on trays (i.e. – water not in equilibrium), but the Enhanced Inside-Out method does. That is the main difference between those 2 methods. The Sure algorithm is good for mechanically complex columns and the Chemdist algorithm is good for thermodynamically complex columns. The rest of the algorithms available are all for special types of column calculations and are not generally suggested for use unless you have a specific process that they are applicable for. If you have further questions about when to use each algorithm, you can refer to the Help menus in PRO/II.
Tray hydraulics are only significant if you need to take the hydraulic calculations into consideration. Otherwise, if you are only looking to achieve a specific separation, you could probably not use them and design the column to achieve your main separation goals. It all comes down to what’s most important for you and what it is that you are trying to accomplish with your column and your model.
I know the important to the thermodynamics and the feed composition, but do you don´t have any tips or simulation troubleshooting for the moment to do simulation of distillation columns?
I’m not exactly sure what you’re asking. Are you asking for thermodynamic tips for distillation columns? If so, it’s all going to depend on the process. With any unit operation (distillation column or not), your choice of thermodynamic method comes down to a few factors –
i. What components do you have?
ii. What compositions do you have of these components?
iii. What’s your operating temperature and pressure?
Those factors determine which thermo method is best suited for your process. You can get more thermo recommendations by going to our thermodynamic reference manual. That is accessed by going to Help à Reference Manual from within PRO/II, then selecting “Volume I: Component Data and Thermodynamic Methods”. You could also call your local tech support hotline for advice. To find your local office, click here
Theoretical tray efficiency recommended for Invensys? Do you have some paper, table or similar?
Tray efficiencies are not necessary in PRO/II unless you are using the actual amount of trays for your column. If you have already converted your column to a theoretical number of trays and are using that value as the number of trays for the column, then you have already taken into consideration any efficiencies you may have.
The algorithm used for default is good, but depending for the evaluate case, some recommended for this cases
There are several algorithms available to you within the column. The default is Inside-Out. This is a very good algorithm because it is widely applicable to both mechanically complex columns as well as thermodynamically complex columns, it’s forgiving of bad initial estimates, and it solves very fast. This method does not take into account free water on trays (i.e. – water not in equilibrium), but the Enhanced Inside-Out method does. That is the main difference between those 2 methods. The Sure algorithm is good for mechanically complex columns and the Chemdist algorithm is good for thermodynamically complex columns. The rest of the algorithms available are all for special types of column calculations and are not generally suggested for use unless you have a specific process that they are applicable for. If you have further questions about when to use each algorithm, you can refer to the Help menus in PRO/II.
For the absorbers, liquid-liquid extraction, I have some questions for technical support.
What questions do you have? You could also call your local tech support hotline for advice. To find your local office, click here
What questions do you have? You could also call your local tech support hotline for advice. To find your local office, click here
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