4 replies to this topic

[Dieguito2]

Dears,

Can you suggest what type of safety devices shall be used for crude oil service when sludge and / or sand can be present in the relief flow? A PSV manufacturer that I have contacted advise against the use of normal PSV because the solids can destroy the valve seat at the first use.

[shan]

How about rupture disc?

[fallah]

Dears,

Can you suggest what type of safety devices shall be used for crude oil service when sludge and / or sand can be present in the relief flow? A PSV manufacturer that I have contacted advise against the use of normal PSV because the solids can destroy the valve seat at the first use.

 

Dieguito,

 

With lack of adequate info, a combination of RD/PSV might be used for such service. RD at upstream to prevent the PSV seat/disc to be subject to dirty fluid in normal operation and a special PSV at downstream with internals (seat,disc) of the very hard material to resist against solids erosion during relief. 

 

How much are the sizes of the solids?

Edited by fallah, 29 October 2018 - 08:00 AM.

[Dieguito2]

Hi Fallah,

Solids dimension is unknown, anyhow I expect sand less than 0.1 mm in diameter.  My costumer is concerned of dirty accumulation in PSV inlet line and asks for a valve equipped with lifter lever for manual relief, if I follow this request rupture disks are excluded. Set pressure here is low: 8 barg. Can you share information about special PSV with hardened seat? Do you have experience of this kind of service?

 

Regards

[fallah]

 

Solids dimension is unknown, anyhow I expect sand less than 0.1 mm in diameter.  My costumer is concerned of dirty accumulation in PSV inlet line and asks for a valve equipped with lifter lever for manual relief, if I follow this request rupture disks are excluded. Set pressure here is low: 8 barg. Can you share information about special PSV with hardened seat? Do you have experience of this kind of service?

 

 

Dieguito,

 

It's not uncommon using a small size line handling the continuous purge of steam or a cleaning medium such as gasoline which is connected to the inlet line of a PSV on dirty services such as a solid containing fluid and would flush the PSV upstream to prevent accumulation of solids there. Obviously the detail of connection and applied spray nozzle should be such that there would be no negative effect on PSV function to do the job properly...

 

The nozzle of relieving the clean fluid can be (or even has to be) oriented toward the PSV if we expect to prevent deposit formation at PSV inlet, provided that the relevant flow rate hence the velocity of the clean fluid would be kept within a range in which there is no concern of erosion or severe impingement on PSV disc...

 

The specialty of the PSV would be limited to the materials of its internals i.e. seat and disc and it's adequate to select the materials hard enough to resist the erosion of contained solid during relief.