There is no top condenser in proii
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I recently used ProII to simulate a distillation column; in this setup, no condenser was placed at the top of the column, and instead the vapor was taken from the top and then condensed. However, this approach didn’t work for calculating the column performance. I was wondering if there are other users who have encountered this same issue? How was it solved? I came up with a solution on my own: in the heaters and coolers, I assigned a cooling load to the first panel, so that it can be calculated. However, I’m not sure whether this setup is correct or not, nor what the reliability of the results will be. I hope everyone can share their opinions and we can discuss this together. . . .
Your settings are fine. In PROII calculations, for tower modules, it is required that the first plate must have liquid-phase reflux (or inflow to the tower); otherwise, the program considers it to be unsatisfactory and calculation cannot proceed. When you provide a liquid flow stream to the first plate, or when there is a COOLER on the first plate, this condition is met, and therefore it is allowed in the calculations.
Agree with the view on the second floor. Providing the cooling load is equivalent to having a condenser.
:loveliness: :loveliness: :loveliness: :loveliness:
Bro, why not use partial condensation? This should solve the problem
There’s still one thing I’m not quite clear about: 1. If I set the load on the first tray in the heaters and coolers to zero, the temperature of the gas phase exiting the top of the tower will be close to the boiling point of the components. Is this okay? 2. Even if the cooling load for the first tray is specified, what amount is appropriate?
1. The load is 0; it should be possible to perform the calculation (I haven’t tried it yet). . ). But it certainly won’t converge. . 2. As for what appropriate load level is? It depends on your specific calculation rules. For example, temperature, indicators, and so on; this load is used as the dependent variable for calculation. :)
I determine the load amount based on the temperature at the top of the tower; since the temperature there is around 70 degrees, I set the load value for the first panel to that temperature. Is this approach acceptable?
Absolutely possible:victory:
The first panel, combined with the cooling load, has the same effect as a top-condenser, but I’m not sure why the original poster would choose this approach – wouldn’t using a condenser directly be sufficient? Another point is that if the substance at the top of the tower is not a pure compound, then the concept of boiling point does not apply; only pure compounds have a boiling point.
I am simulating the reactive distillation of ethyl acetate, using a two-stage condensation process; I did not use the condenser built into the tower. Let’s briefly describe the process first: The gas phase enters the tower from the bottom, while ethyl acetate, water, and ethanol are extracted from the top of the tower. After secondary condensation, the mixture enters a phase separator, where it is divided into three streams – one stream is extracted, while the other two are used as reflux streams at the top and middle sections of the tower, respectively.
When performing azeotropic distillation with phase-separated reflux, no condenser is installed at the top of the tower. The situation described by LZ does indeed occur; generally, two approaches can be taken: 1. Set an initial value for the reflux line of the tower, which can accelerate convergence; 2. An additional liquid feed can also be introduced at the first stage at the top of the tower, with a feed rate of either 0.1 or 0.01 kg/h – this does not affect the results while still helping to speed up convergence. I usually use the second method, which I find to be the most effective.
Thank you for your answer. Is it possible to set it up as I described above? I’m going to try your method··~
The failure to converge may be related to PROii’s algorithm; it mainly indicates no backflow at the dry plate or at the top of the tower, whereas Aspen does not experience such a situation. By setting a cooler, it is possible to reduce the load value; by \"low\" I mean a relatively small value. For example, for the main cooler at the top of the tower, a value of 0.01% should not affect the results. If there are no issues with the settings related to the material, convergence should also occur.
I’ve learned it; please talk more so I can listen
Without reflux, the function of the distillation tower is merely flashing