Design pressure of the reflux tank at the top of the vacuum distillation tower
Thread Content
The pressure at the top of the vacuum tower is -0.97 MPa; the design pressure for the gas-liquid separator can be set at -0.1 MPa. What about the reflux tank at the top of the tower? Is it necessary to design it for negative pressure? The material inlet of the reflux tank is bottom-fed, which is equivalent to having a liquid seal. My consideration is that under abnormal conditions, the return tank may experience negative pressure; therefore, it should be designed for negative pressure. Another issue is that it is designed for normal pressure, but pressure testing is done under negative pressure. I heard a teacher say that, but I don’t quite understand this negative pressure check. I earnestly request your advice.
The pressure at the top of the vacuum tower is -0.97 MPa – what’s the problem?
It is best to design it with negative pressure, as there are too many such abnormal situations.
The unit of measurement is wrong; bar is roughly the right value
It must be equivalent to the negative pressure at the top of the tower; otherwise, how can the condensate reach the reflux tank?
-0.097 Incorrect entry-_-||
Currently, the vent pipe of the reflux tank is directly connected to the exhaust main, designed for normal pressure conditions.
In a reflux tank, the operating pressure is usually positive, and it is roughly equal to the outlet pressure of the pressure reduction system. Therefore, as the instructor suggested, it is sufficient to design for a slightly positive pressure and then verify it against negative pressures. In the worst-case scenario, a negative pressure of below -0.09 MPaG may still occur; this can happen when there is no water in the reflux tank, no condensation takes place in the condenser, and pumping is done under vacuum conditions