How should clause 3.9.3 of the new Code be understood?
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In clause 3.9.3 of the new Code, table 3-4 specifies that when the critical temperature of the liquefied gas is <50°C, the operating pressure is to be “the gas pressure at 50°C under the maximum filling volume specified in the design”. How should this operating pressure be determined or calculated? Someone has already asked this question, but no one has provided an answer yet. I don’t know the answer either; let’s change to another topic (hehe). Please forgive me, experts
It is recommended to refer to the relevant sections of the 99th edition of the Pressure Vessel Code; the chemical process engineers shall carry out the calculations to determine the saturated vapor pressure at the design temperature
Version 99. . . It’s really hard to find this. Could some kind-hearted folks take the time to explain it to me? . .
Regarding point (1) in Table 3-4 of Section 3.9.3 of the new Regulatory Requirements, where the critical temperature of the liquefied gas is < 50°C, the operating pressure is specified as \"the gas pressure at 50°C under the maximum filling volume specified in the design\". How should this operating pressure be determined or calculated? "The response is as follows: The value of the operating pressure can be determined by referring to relevant data (see the values of saturated steam pressure for common substances attached below). The principle for selecting this pressure is that it should not be lower than the saturated steam pressure at 50°C. Attached are the values of operating pressure for several substances at the specified temperatures during storage at room temperature: Substance name, Saturated steam pressure at 50°C (MPa): Propylene – 2.05, Propane – 1.71, Isobutane – 0.69, Ammonia – 2.03, Chlorine – 1.43
First, I’d like to thank the colleagues above. Please take a look at Table 3-4 of the new regulations before answering. What I’m trying to say is that for example, in the case of CO2 liquefied gas containers, whose critical temperature is 31.1 degrees, if there are no cooling measures and no experimental measurements of the temperature, then when the temperature exceeds 31.1 degrees, it will no longer be in liquid form, right? Where does the saturated vapor pressure come from? So how is the design pressure determined? Please continue the discussion and give ratings
According to what “haisiran” said regarding the CO2 liquefied gas container, its critical temperature is 31.1 degrees; there are no cooling measures in place, nor are there any experimental measurements of the temperature. Therefore, when the temperature exceeds 31.1 degrees, with no cooling measures and no experimental data available... It is sufficient to use the gas pressure at 50°C under the maximum filling volume specified in the design – as explained in Table 3-4. This value represents the operating pressure; the design pressure must also take into account an appropriate design margin, as well as the need for overpressure relief devices.
Just to ask again: once the filling coefficient is determined, can this working pressure be calculated, or does it need to be looked up in a table? More specifically, please
Looking up this value in a table, the saturated vapor pressure at 50 degrees is..
Reply to 8# cjrqndt: The critical temperature of CO2 is 31.1°; at 50° it is entirely in gas form, so what’s the point of talking about saturated vapor pressure?
Reply to 9# haisiran: The pressure of a pure gas can be approximated by using the ideal gas law
Is PV=nRT correct? Should I use this formula to calculate it?