aspen batch distillation simulation

I have temporarily found the problem. The unit of heat transfer coefficient under setup-jacket heating is KW/m2/K, so the previous coefficient should be 0.5 instead of 500. But there is still something unclear. Is the medium temperature above the heat transfer coefficient filled in with normal temperature or unheated temperature? That is to say, the heating medium is 150 degrees steam. Should I fill in 150 here or the ambient temperature of 20 degrees?

Is batch distillation really niche?

1. Your operating conditions are set incorrectly. You set the jacket at 150°C and 0.5kw/mK at the beginning, so operation1 (charge) is already taking effect. You started heating within 0.5 hours. After 0.5 hours, the Ninth Allegro has already exceeded 80°C, so it will naturally stop. 2. In addition, if you start the tower with an empty tower, the inert substance is nitrogen. When the tower is started with an empty tower, nitrogen occupies the entire volume by default.

This post was last edited by ljy3033 on 2017-12-14 11:43. Is it operating steps? The above parts are filled in with initial values. For example, if 150 degrees steam is used for heating, fill in the ambient temperature of 20 degrees before starting. (After the software ran the results, why did the medium temperature change from 20 degrees to 150 degrees? Is it necessary for the software to change this initial value? ) However, in the Aspen installation directory, there is a sample file "HeptHexOct.bspf" in Aspen Batch Distillation V7.2---Examples---HeptHexOct. The medium temperature of the sample file is filled in with the temperature of the heating medium of 140°C. There are calculation results after running it, but when I fill in 150℃ in my simulation file, the running time exceeds 48 hours. I don’t understand where the problem lies?

Yes, it is the initial value. This value is the value when you first run it. As for the value that later changed from 20 to 150, you must have changed it in the operation. This is the same as the actual situation. In fact, you do not heat it at first, but then start heating it after feeding the material. The example you mentioned is that the operating conditions are heating while feeding. It all depends on the operating conditions. The K value of your jacket is so high. If you start heating, it will burn to more than 100 degrees in a few minutes. Think about it, after 0.5 hours, the temperature of your kettle will be 150°C (close to the heating source) temperature), how does it stop (you set it to 80 to stop), the conditions cannot be met no matter what, so the calculation continues. As for more than 48 hours, it is the default setting of the software. If an operation runs for 24 hours and does not produce results, it will stop and run the next one.

Hello, excuse me. I encountered a small problem when using the batch optimization function. Please take a look at it if you have time. I want to set the reflux ratio as a control variable, but when I drag the reflux ratio from reflux Results to optimization, I get an error and cannot drag it there. Did I find the wrong location?

This post was last edited by zhxbkofkyo on 2017-12-18 13:20. I have never used this function. I tried it and clicked on optimization, and the message "The operation attempted is not supported" appeared. This prompt box appeared every time a single operation was performed. I can't go down. Sorry, I can't help you.

Analyzing the reason, it may be that the control variable can only be of Fixed type, and your reflux ratio has been stipulated in the control settings and should be a free variable, so it is not allowed to be added. In addition, what is the difference between Decision Variables and Control Variables?

According to the explanation of the help file, Decision variables are divided into three types, namely normal decision variables, control variables, and initial variables. See attached picture for details.