DDURAND
Petroleum
- Nov 3, 2010
- 1
Dear all,
My concern is as follows: in the original design, the LPG coming from the ship enters the bottom of the sphere, while a vapor line was provided to avoid any pressure buildup in the sphere during LPG filling. To eliminate the vapor line in view to money savings, we suggest to provide a top spray filling system (spray ring) in the sphere.
As a matter of fact, we know that top spray filling will cause an intimate mixing of the incoming liquid with the vapor present in the vapour present in the storage vessel resulting in an accelerated condensation of the vapours.
I quite understand above explanation if the liquid introduced in the sphere is subcooled compared with the gas/liquid already present in the sphere (for example a liquid at 34°C feeding a sphere with liduid and gas in equilibrium at 40°C). The fact to spray the LPG improves the contact with the vapor phase, some vapor condensation resulting from thermal transfer.
But all design practices indicate that when spray filling is provided,a vapor balance line is not used, but without precising that the liquid must be imperatively subcooled.
Can you confirm that the pressure buildup is well limited when using a top spray ring, even the liquid is not subcooled. In that case, how can you explain the condensation of the vapor? Is the fact to spray the liquid through the ring results in a temperature drop of the liquid (droplets temperature less than liquid temperature upstream the spray ring)?
Thanking you in advance for your help.
Dominique
My concern is as follows: in the original design, the LPG coming from the ship enters the bottom of the sphere, while a vapor line was provided to avoid any pressure buildup in the sphere during LPG filling. To eliminate the vapor line in view to money savings, we suggest to provide a top spray filling system (spray ring) in the sphere.
As a matter of fact, we know that top spray filling will cause an intimate mixing of the incoming liquid with the vapor present in the vapour present in the storage vessel resulting in an accelerated condensation of the vapours.
I quite understand above explanation if the liquid introduced in the sphere is subcooled compared with the gas/liquid already present in the sphere (for example a liquid at 34°C feeding a sphere with liduid and gas in equilibrium at 40°C). The fact to spray the LPG improves the contact with the vapor phase, some vapor condensation resulting from thermal transfer.
But all design practices indicate that when spray filling is provided,a vapor balance line is not used, but without precising that the liquid must be imperatively subcooled.
Can you confirm that the pressure buildup is well limited when using a top spray ring, even the liquid is not subcooled. In that case, how can you explain the condensation of the vapor? Is the fact to spray the liquid through the ring results in a temperature drop of the liquid (droplets temperature less than liquid temperature upstream the spray ring)?
Thanking you in advance for your help.
Dominique
