Naphtha dry point
Thread Content
With the bottom temperature of the fractionation tower and the top pressure held constant, why does the bottom temperature increase instead of decreasing when the reflux flow rate is increased? Also, does the inlet temperature of the reflux tank affect the dry point of naphtha? Seeking advice. . .
Check whether there are significant fluctuations in the feed temperature to the tower, and whether there are large variations in the temperature of the reflux tank after air cooling~~~~
Under normal circumstances, increasing the return flow rate leads to cooling! How could it increase? After all, the temperature of the reflux is lower than that at the top of the tower. If no other parameters are changing, it is recommended to check the thermocouple! Factors affecting the dry point include the properties of the feed oil, bottom temperature, top temperature, and top pressure
If the parameters remain unchanged, check the feed composition.
Is it appropriate to use backflow irrigation with water cut-off?
This situation is likely due to excessive reflux flow, which overloads the distillation section; the opening of the bottom valve remains unchanged, the pressure control opening at the top of the tower is too large, resulting in poor cooling effects – thus creating a vicious cycle at the top of the tower! Dryness is only related to the tower top temperature and tower pressure!
When the bottom temperature is constant, the top temperature and pressure are proportional to each other. Reflux is a naphtha component, and all of the reflux eventually comes out from the top of the tower. When the backflow increases excessively, the load at the top of the tower rises, and the pressure at that location increases as well. If the pressure at the top of the tower is not adjusted in a timely manner, the temperature there will increase. In a situation like the one you described, it’s possible that the reflux flow is too high, causing the top of the tower to become overloaded. In such cases, it’s possible to reduce the reflux flow and increase the circulation in the various intermediate sections, thereby extracting heat through those intermediate sections. The dry point of naphtha is only related to the top pressure and top temperature of the tower.
The inlet temperature of the reflux drum does not affect the dry point of naphtha.
The temperature of the reflux returning to the tower is high, the amount of liquid extracted is large, and the water cooling effect is poor; although there is a large amount of reflux, the temperature does not drop but instead rises.
Could excessive backflow cause leakage at the top trays of the tower? Should the top temperature be reduced?