How should the pressure be selected for pressure vessel equipment/tube flanges using ammonia as the filling medium?
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For pressure vessels whose filling medium is ammonia, must the pressure ratings of both the equipment flanges and pipe flanges be set at PN2.5?
It’s on hg20583; check the book
There are no new flange standards for PN2.5; it’s probably PN25
I’m not sure if it relates to high permeability; if so, there are similar requirements – not only regarding the grade but also the sealing surface and flange type
The medium is “ammonia gas, ammonia aqueous solution””
The saturated vapor pressure of liquid ammonia at 50 degrees is 1.93 MPa, so it’s normal to choose 2.5 MPa.
It’s an aqueous solution of ammonia; is 1.6 okay? It’s not liquid ammonia.
Ammonia is a highly permeable medium; according to HG/T20583-2011, the pressure class of pipe flanges must be no less than 2.0 MPa, while there are no mandatory requirements regarding equipment flanges at present. However, HG/T20583 is about to be revised; based on the current draft, requirements regarding the pressure class of the equipment flanges have been added, stipulating that this pressure class must not be lower than 1.0 MPa
For ammonia and aqueous solutions, do the sealing surfaces also need to be uneven?