This paper analyses the effects of pressure surge on pipe flow. The surge pressure investigated is that propagated by the emergency relief coupling valve (ERV) connected to a loading system carrying crude oil from fou...This paper analyses the effects of pressure surge on pipe flow. The surge pressure investigated is that propagated by the emergency relief coupling valve (ERV) connected to a loading system carrying crude oil from four flow stations. The results of the analysis show remarkable changes in the fluid parameters arising from the shut down of the loading system by the ERV in the event of storm. For instance, in pipe 1 the pressure dropped from an initial value of 25 × 105 N/m2 to 19 × 105 N/m2, while the velocity of flow increased from 1.76 m/s to 2.97 m/s. The system showed high Reynolds number indicating turbulent flow and the Mach number in pipe IV as high as 3.6 indicating supersonic flow. The consequence of the pressure drop is column separation or cavitations. If the bubbles collapse, re-surge pressures occur leading to possible leakages and rupture of the pipes. All these can be minimized by selecting appropriate surge suppression devices for the system.展开更多
This paper discusses the influence of valve operations on pressure surge in a pipeline. The valve is a protective type which remains open in a pipeline loading system during normal operation but shut down the system w...This paper discusses the influence of valve operations on pressure surge in a pipeline. The valve is a protective type which remains open in a pipeline loading system during normal operation but shut down the system when there is an emergency such as storm. The data for the study were obtained from measurements at Agbada 1 flow station as well as log sheets. Also, calculations were made using existing and derived formulas to obtain the values of Crude Oil and Pipe parameters that could not be measured directly or derived from data or log sheets. Surge analysis was carried out on the pipeline system to ascertain changes in pressure and flow rates along the pipeline following valve shut down at any time using developed pressure and flow equations. The results of the simulation analysis showed remarkable changes in the fluid pressure and flow rates along the pipe on shut down at any time. The pipeline recorded the highest pressure of 37.4 bar against initial pressure of 25 bar at length 6000 m in 1.5 second valve closure. There is also remarkable pressure drop along the pipe capable of reducing the crude oil pressure below its vapour pressure. The flow is turbulent even before valve operation with Reynolds number as high as 57024.53. The model equations compute changes in pressure and flow rates at different points in a pipeline installed with emergency-relief coupling valve. This enables point of extreme and low pressure to be detected accurately in a pipeline which guides the engineer while positioning surge suppression devices which cushion the effects of pressure surge in any pipeline.展开更多
文摘This paper analyses the effects of pressure surge on pipe flow. The surge pressure investigated is that propagated by the emergency relief coupling valve (ERV) connected to a loading system carrying crude oil from four flow stations. The results of the analysis show remarkable changes in the fluid parameters arising from the shut down of the loading system by the ERV in the event of storm. For instance, in pipe 1 the pressure dropped from an initial value of 25 × 105 N/m2 to 19 × 105 N/m2, while the velocity of flow increased from 1.76 m/s to 2.97 m/s. The system showed high Reynolds number indicating turbulent flow and the Mach number in pipe IV as high as 3.6 indicating supersonic flow. The consequence of the pressure drop is column separation or cavitations. If the bubbles collapse, re-surge pressures occur leading to possible leakages and rupture of the pipes. All these can be minimized by selecting appropriate surge suppression devices for the system.
文摘This paper discusses the influence of valve operations on pressure surge in a pipeline. The valve is a protective type which remains open in a pipeline loading system during normal operation but shut down the system when there is an emergency such as storm. The data for the study were obtained from measurements at Agbada 1 flow station as well as log sheets. Also, calculations were made using existing and derived formulas to obtain the values of Crude Oil and Pipe parameters that could not be measured directly or derived from data or log sheets. Surge analysis was carried out on the pipeline system to ascertain changes in pressure and flow rates along the pipeline following valve shut down at any time using developed pressure and flow equations. The results of the simulation analysis showed remarkable changes in the fluid pressure and flow rates along the pipe on shut down at any time. The pipeline recorded the highest pressure of 37.4 bar against initial pressure of 25 bar at length 6000 m in 1.5 second valve closure. There is also remarkable pressure drop along the pipe capable of reducing the crude oil pressure below its vapour pressure. The flow is turbulent even before valve operation with Reynolds number as high as 57024.53. The model equations compute changes in pressure and flow rates at different points in a pipeline installed with emergency-relief coupling valve. This enables point of extreme and low pressure to be detected accurately in a pipeline which guides the engineer while positioning surge suppression devices which cushion the effects of pressure surge in any pipeline.
