Air cooling issues
Thread Content
If the overhead air cooling in a distillation tower stops during normal operation, what series of changes will occur? More specifically????
1. Increase in tower top pressure； 2. The temperature at the top of the tower increases after cooling ； 3. The liquid level in the tower top reflux tank decreases ； 4. If a cooler is present, the temperature of the circulating return water rises ； 5. The product at the top of the tower is substandard. Let’s talk about these first.
Article 5? There are generally no issues with the product at the top of the tower; however, this might cause the light components to be pushed to the bottom of the tower, resulting in substandard product at the bottom
If the pressure remains constant, the heavier components will rise, resulting in a heavier composition at the top of the tower!
Pressure is bound to rise, how can it not?
We can break down this topic to see how it can change When there is headroom for pressure control, the control valve adjusts according to the pressure; at this time, the product recombination within the tower moves upward as the temperature rises! But when there is no room for control of the pressure at the top of the tower, even with the control valve fully open, the pressure cannot be maintained; at this point, the pressure inside the tower will gradually increase, leading to the situation you mentioned! Operation is a dynamic balance; changes within it need to be taken into account in order to achieve a more comprehensive analysis
We can first determine the control method for the top pressure of this distillation tower; does the reflux tank have a process for venting non-condensable gases? If the top pressure of the tower is simply controlled through air cooling/water cooling, it will rise uncontrollably ； For other heat bypass/strangling point or combined control solutions, further analysis is needed; however, the overall trend is an increase. Not only is the vapor phase at the top of the tower unable to be condensed, but the increased temperature after cooling/recovery also affects the gas-liquid equilibrium within the tower..........
Okay, I understand what you mean! :P
Mm, the analysis is very comprehensive; I’ve learned a lot
If it’s a bottleneck heat bypass configuration, and this situation occurs, please analyze it
I don’t seem to have seen this type of design before; usually, heat bypass systems are paired with water cooling (with the water cooler placed below the return tank)； It’s not easy to implement a thermal bypass in combination with air cooling, so there’s no risk of the air cooling system stopping suddenly :) Sorry about that.