Issues with safety valves on the top of reaction vessels or separation tanks
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Problems with the safety valves on the top of the reaction tank or separation vessel? In the data sheet for the safety valves at the top of the reaction vessel or separation tank: parameters such as specific heat ratio Cp/Cv, compressibility factor, density in kg/m3 – should these values be based on a pure gas phase, a pure liquid phase, or a two-phase mixture? I’m quite confused and need some guidance
The medium discharged by the safety valve should be the same as the medium inside the equipment in contact with the safety valve – gas is gas, and liquid is liquid. Assuming that the liquid medium will vaporize after pressure is released through the safety valve, it is a matter of designing the diameter of the pipeline behind the safety valve; by increasing the diameter gradually, there will always be an appropriate solution.
Thank you. I’ve been working on calculations related to safety valves recently, but API520, 521, or HGT standards don’t provide detailed information on this topic. Do you have any materials related to safety valves? I’d like to learn more about it. Thank you
The selection of physical property parameters in the safety data sheet should still be determined based on the calculation conditions for the release volume. If, in the case of a safety valve at the top of the reactor, failures of the control valve, accidental closure of the valve, or blockages occur, it is the gas phase within the reactor that causes overpressure; therefore, the physical property parameters in the data sheet should reflect those of the gas phase； If the safety valve takes fire into account, then the physical properties should be those of the gas phase resulting from the vaporization of the liquid phase in the reactor during a fire, rather than those of the gas phase originally present at the top of the reactor.