Original startup sequence for the distillation tower
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I saw a post saying that after the vacuum testing of the distillation tower is completed, pressure should be increased first, then the temperature raised, and finally the reboiler and condenser put into use. I understand the concept of boosting pressure by filling it with nitrogen, but how can the temperature be increased before the reboiler is put into use? Please provide an explanation
Establishing operating conditions requires a step-by-step approach, with these steps taking into account the characteristics of the medium as well as the principles of distillation. Establishing distillation operating conditions step by step is a process. Every step is backed by a principle. It is recommended to start by learning the principles of distillation columns*.
The principles in this regard are included in your process flow diagram. There is rising vapor and flowing liquid. This needs to be established in advance, and temperature-related involvement is required thereafter. I work with distillation towers for deep-cold oxygen production, and the principle is the same in all cases.
As I understand it, once the flushing to ensure airtightness is complete and the process has been verified to be correct, the pressure in the tower is increased to the operating pressure; feeding then begins to establish a liquid level. After that, a heat source is applied to the reboiler, causing the temperature at the bottom of the tower to rise, and a condenser is installed at the top of the tower to establish reflux. I’m confused: some say that the temperature should be raised first, and then the reboiler should be used. But since the reboiler isn’t in use, where does the heat come from? Please explain, sir
This depends on your process; normally, a reboiler needs to be installed first
For some processes, it is possible to turn on the tower heating before introducing the reboiler (for example, some substances will polymerize when exposed to cold after being heated by steam), which is equivalent to raising the temperature.
If it can be convinced you in principle and is in line with the regulations, then you are right. I don’t like it when certain people say this, because if something goes wrong, these same people will step forward to blame you. Don’t argue; everything we do is justified and backed by principles. It can’t be fake; believe in yourself.
I now truly understand the saying that it’s better to have no books than to blindly trust what they say.
When performing distillation operations for ordinary organic chemical products, we generally start by feeding the material in, creating a vacuum, and then gradually increasing the temperature.