Discussion on the location placement of pressure relief valves in process pipelines
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Regarding the discussion on the location of pressure relief valves in process pipelines, the high-pressure stream at 15 MPa is reduced to 0.5 MPa in a gas-liquid separation tank. Generally, to prevent the effects of volume expansion due to gasification on the pipelines, these pipelines are placed near the gas-liquid separation tank. However, in some special process requirements, the control valve must be placed in the middle of the pipeline. So how can the impact of gas on the pipelines be mitigated? Are there any relevant standards or calculation methods for this?
Were the requirements for the length of the straight pipe section downstream of the valve the reason why the valve was placed in the middle of the pipeline? Behind the valve, a gas-liquid two-phase flow is formed. Using INPLANT or other fluid dynamics calculation software, the flow velocity, pressure drop, and flow pattern of this gas-liquid two-phase flow behind the valve can be determined; the appropriate pipe diameter can then be selected in accordance with SH/T3035. Of course, gas-liquid two-phase pipelines can be reinforced to avoid vibration.
The pipeline downstream of the valve is calculated based on the gasified state; this is how we usually handle it.