I´m designing an LPG pipeline and I´ve a main dobut that I´ve found in NFPA598, FNPA59, API2510 and other LPG norm.
My doubt is how to consider the NPSH for a booster pump, not the calculus.
The project is a Marine terminal for unload LPG. Ships containing GLP must be unloaded/discharged into storage spheres of 5000 m3 of capacity each of them (10 spheres). The distance from ship to factory where the booster pumps will be installed is of 4400 linear metres with a cota/level increase of 50 m with a 12" pipeline. Up to that point the GLP will be pumped by means of the ships pumps. The main problem is that the storage spheres are located at a height of 170 m above sea level therefore the booster pumps will be responsible for supplying the necessary pressure to overtake discharge loss, the increase in level and the pressure inside the storage spheres (6 barg).
The ships discharging GLP will be all different therefore it is very likely that conditions such as pressure and temperature will vary. The ships pumps will be able to supply 800 m3/h to the plant where are placed the booster pump
It is very likely that the pressure and temperature conditions reached by GLP when getting to the booster pumps area will not be balanced, which means that the GLP will be undercooling the pressure, the moment of discharge is indeed of utmost importance since at the beginning the temperatures will be higher. The aereal part of the gas pipeline (500 m) is insulated and the remaining part is buried therefore will be gradually cooling and the temperature at which the GLP reach the pumps will be lower.
My doubt is if for to know the supply pressure of the ship, i have to increase the pressure drop in the pipeline to the vapor pressure of the LPG (at ambiente temperature for example) to ensure that at the suction of the booster pump I have liquid phase for its proper work.
It is expected that in normal conditions the pump will run in liquid phase (although some gas phase could be dragged) and variable temperature.
The idea is to install two pumps running in parallell so as to reach a caudal of 800 m3/h nominal discharge, this booster pump will supply the head to reach the storage spheres.
My doubt is how to consider the NPSH for a booster pump, not the calculus.
The project is a Marine terminal for unload LPG. Ships containing GLP must be unloaded/discharged into storage spheres of 5000 m3 of capacity each of them (10 spheres). The distance from ship to factory where the booster pumps will be installed is of 4400 linear metres with a cota/level increase of 50 m with a 12" pipeline. Up to that point the GLP will be pumped by means of the ships pumps. The main problem is that the storage spheres are located at a height of 170 m above sea level therefore the booster pumps will be responsible for supplying the necessary pressure to overtake discharge loss, the increase in level and the pressure inside the storage spheres (6 barg).
The ships discharging GLP will be all different therefore it is very likely that conditions such as pressure and temperature will vary. The ships pumps will be able to supply 800 m3/h to the plant where are placed the booster pump
It is very likely that the pressure and temperature conditions reached by GLP when getting to the booster pumps area will not be balanced, which means that the GLP will be undercooling the pressure, the moment of discharge is indeed of utmost importance since at the beginning the temperatures will be higher. The aereal part of the gas pipeline (500 m) is insulated and the remaining part is buried therefore will be gradually cooling and the temperature at which the GLP reach the pumps will be lower.
My doubt is if for to know the supply pressure of the ship, i have to increase the pressure drop in the pipeline to the vapor pressure of the LPG (at ambiente temperature for example) to ensure that at the suction of the booster pump I have liquid phase for its proper work.
It is expected that in normal conditions the pump will run in liquid phase (although some gas phase could be dragged) and variable temperature.
The idea is to install two pumps running in parallell so as to reach a caudal of 800 m3/h nominal discharge, this booster pump will supply the head to reach the storage spheres.