1 reply to this topic

[hocon]

Hi,
I am working on distillation column to separate methanol from water. In the lab, we run it in pilot-scale. We also have Aspen model to able to determine the output.
I need to scale up the distillation capacity to 141 times, but I don't know how to determine the height and the diameter of the scale up. I will scale up when the distillation give smallest reboiler and condenser duty to minimize the cost.

Thanks for your help

[djack77494]

hocon,
You have an interesting problem. If you are modeling or doing laboratory scale experiments or measurements, then you are dealing with ideal or nearly ideal conditions. Performing the design of an industrial distillation column bears very little similarity to what you are doing. When you say you are scaling up 141 times, I will assume you mean that the mass flowrates will be 141 times what your pilot flowrates are (as opposed to a very different scaleup of physical dimensions). So what changes and what does not and what is completely different?

The number of theoretical stages remains unchanged. You will use a factor determined from experience to go from how many theoretical stages you need to how many actual stages are required. Your condenser and reboiler duties should scale in proportion to the mass flowrates. The biggest "surprise" for you may be the size of the distillation column. You must design the column using industrial design methods, and nothing you have described to this point have any bearing on how to perform that design. You may refer to some of the excellent textbooks available for industrial distillation column design and operation to get some clues. I highly recommend that you do so. Basically, you will design around column flooding and you will use practical established tray seperations. Combined with "a few other details", this will determine your column's dimensions. There is much more to be learned, and it will take a lot of time and effort to learn it. Good luck.