Issues related to the pressure values corresponding to saturated steam
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This post was last edited by Fish Can’t design on 2018-10-16 at 17:27. Currently, there is a tank with an operating pressure of -0.08 MPa and a design pressure of -0.098 MPa; the operating temperature is 70 degrees, while the design temperature is 100 degrees (as specified by the process). The question is: the saturated steam pressure at 100 degrees is 0.1 MPa. So, won’t there be a conflict between 0.1 MPa and -0.098 MPa? How should this be considered? What should the design pressure be?
Is the operating pressure of this tank negative?
There is no conflict, because the temperature simply cannot reach 100 under negative pressure
It doesn’t say here whether the medium is water or water vapor, right?
If the tank operates under negative pressure, there should be two design pressures: one for positive pressure and one for negative pressure
Is the saturated steam mentioned by the poster water vapor?
The original poster will understand once they take a look at the attached table showing the relationship between pressure and temperature for saturated water vapor. Gauge pressure is -0.09 MPa; the absolute pressure is therefore 0.01 MPa (10 KPa). The corresponding temperature is approximately 46 degrees. -It is definitely incorrect to use 100 degrees as the design temperature at 0.1 MPa.