Due to the self-vaporization of ammonia, the design pressure should be no less than 2.16 Mpa? !
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Now, a plate heat exchanger is being designed to heat ammonia-containing wastewater to around 50-60 degrees Celsius. While searching for information online just now, I came across a post on this forum in which a user named Phoenix Reappears said: “What is particularly noteworthy is the self-vaporization of ammonia; when a design temperature of 50 degrees is chosen, regardless of how low the operating pressure is, the design pressure of the equipment must not be less than 2.16 MPa.” Can the auto-evaporation of ammonia cause such high pressure? ! Does my heat exchanger need to be designed this way? ! Thank you! ! !
It shouldn’t be necessary; he was referring to the saturated vapor pressure of pure ammonia. In your case, it’s ammonia water, so it’s sufficient to consider the saturated vapor pressure of ammonia at that concentration at this temperature
What was said upstairs is correct; there’s really no need for such design pressures. The design should focus on pure ammonia instead
Yes, liquid ammonia might need to be designed this way. . .