I would like to ask: the refrigerant ammonia used in ammonia-cooled systems is at 1.6 MPa – will the pressure on the shell side of such systems exceed 2.5 MPa?
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I would like to ask: the refrigerant ammonia used in ammonia-cooled systems is at 1.6 MPa – will the pressure on the shell side of such systems exceed 2.5 MPa? Considering that the gas ammonia outlet valve is closed, can pressure build up? The syngas entering the ammonia-cooled section is at 20 degrees. At 50 degrees Celsius, the pressure of liquid ammonia during flashing is just a little over 2 MPa. Are there any operating conditions under which overpressure could occur? (Tube rupture is not taken into consideration.) Thank you to those who can provide guidance; one should never forget those who helped them:loveliness: This post was last edited by jindin312 on 2009-3-31 at 22:53
The syngas entering the ammonia-cooled section is at 20 degrees. It’s winter, right? A higher probability needs to be taken into account, and the design pressure must account for extreme conditions. But if it’s confirmed that the maximum possible temperature of the heat source input is 20 degrees, then the pressure won’t exceed 2.5 MPa
At 25 degrees Celsius, the saturated ammonia vapor pressure of liquid ammonia is 1.008 Mpa. Since the temperature of the medium to be cooled is 20 degrees Celsius, regardless of the volume of liquid ammonia or whether the outlet valve is closed, a new gas-liquid equilibrium will only be established on the shell side. The pressure of gaseous ammonia cannot reach 2.5 MPa. Go ahead and operate with confidence! :)
If the ammonia gas outlet valve is closed, and only the inlet valve is also closed (or there is a check valve), then the pressure on the shell side cooled by ammonia will exceed the inlet pressure (of course, this also depends on the saturated vapor pressure of liquid ammonia at 20°C). However, if the inlet is connected to the liquid ammonia tank, or if the saturated vapor pressure of liquid ammonia at 20°C is not greater than 2.5 MPa, I don’t think the above phenomenon will occur.
2.5 MPa roughly corresponds to the saturated vapor pressure of liquid ammonia at 50 degrees Celsius. That is, changes in ambient temperature or direct sunlight can cause the temperature of the liquid ammonia to rise to 50 degrees Celsius, resulting in a pressure of 2.5 MPa when there is no flow and the ends are closed.