Increase in system pressure when circulating water is stopped
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A question arose during today’s discussion: the material has a boiling point of 197°C at atmospheric pressure; heating and evaporation are carried out using a 180°C heat source, and the process takes place under negative pressure. The vapor evolved is cooled by circulating water. Discuss whether the system pressure rises above the rated value during power outages, when the circulating water and vacuum pumps stop operating, or when the heat source is shut down. Some people say that the pressure won’t increase much, because the boiling point of the material at atmospheric pressure is lower than the temperature of the heat source; as pressure rises, the material can no longer evaporate continuously, and eventually the pressure returns to atmospheric level. No overpressure release
Just check the saturated vapor pressure at the corresponding temperature. The system’s heat source is at 180°C, yet boiling does not occur; under normal circumstances, the pressure of the main medium alone is not sufficient to reach zero. It is necessary to determine whether an inert gas has been introduced into the system. If it’s charged, the pressure won’t exceed 0.1Mpa even in case of a power outage
The last edit to this post was made by Dedication on 2020-3-18 at 10:31. Let’s think about it in a different way: if the production cycle water system stops working, but the reboiler continues to operate, you’ll find that the tower can still function for a while, until the water cooler can no longer cool the water. At that point, vapor enters the vacuum pump, the operating conditions deteriorate, the vacuum level in the tower drops, and the temperature at the bottom of the tower rises. It can’t be steamed anymore, because the vacuum has been lost. If the corresponding tower top temperature exceeds 100°C, the circulating water boils, the water cooler experiences overpressure, and the operating conditions continue to deteriorate. As a result, the tower will not experience overpressure. In the event of a power outage that results in a stop in water supply as well as a loss of vacuum, I don’t think overpressure will occur; however, it is necessary to shut down the heat source promptly to prevent the material in the tower reactor, which is designed for negative pressure, from deteriorating or caking due to prolonged heating under positive pressure. It’s a problem if the tubes get blocked. The premise of the above analysis is that this tower handles a single type of material