The lowest temperature that the pressure relief device can reach
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Hello everyone. When pressure relief devices such as safety valves and emergency release valves are activated, the rapid drop in pressure can cause the connected equipment or pipelines to reach a certain minimum temperature. This leads to certain limitations in terms of the materials used for these equipment or pipelines, as well as in their operation. I would like to ask everyone to discuss how this minimum temperature is generally calculated. Additionally: Is this minimum temperature indicated in the data sheet for the safety valve/emergency relief valve?
I have the same question as the original poster: whether the pipeline at the outlet of the safety valve should be made of low-temperature material. The data sheet we have provided does not show the lowest temperature after release; most of the internal components such as seals are made of stainless steel, which can withstand low temperatures. Should we roughly consider whether to use the saturation vapor pressure corresponding to the temperature at the outlet pipe pressure?
Since it is not indicated in the data sheet, using all stainless steel may lead to an unnecessary increase in costs.
If it can be determined that low temperatures will occur, can the design temperature be set at that lowest temperature, so as to determine feasibility?
Yes, this temperature is the minimum value of the design temperature. Of course, there is also a maximum value.
That’s a good question; I’ve encountered issues before regarding the selection of outlet piping for safety valves in cases involving propylene and liquid ammonia. . . .
It can be calculated isentropically through a throttling expansion process, etc
Are there any materials I can refer to?
By checking the enthalpy values for specific chemicals, it can be seen that most of them result in a temperature decrease, while there are also those that cause a temperature increase, such as hydrogen.