3 replies to this topic

[rajeshrajan]

Dear Friends,

An existing vessel dedicated to solvent ( Toluene) transfer requires a new 80mm dia vent for 2-phase emergency relief case.

The relief device will be a burst disc

There is no spare 80mm nozzle on tanks, instead i have a couple of DN50 and DN40 piping entering the vessel.

 

So then my question is:

• Can i use takeoff from these smaller lines and combine to achieve the 80mm relief diameter?

 

Feel free if you would require any additional information to proceed.

 

I would appreciate your inputs.

 

Regards,

 

Raj

 

 

[fallah]

Raj,

 

In general, you can combine the take offs from smaller lines to achieve a cross section area equal to that of 80 mm diameter, but it should be investigated if those take offs are from incoming lines, can the entering fluid pressure affect the relieving capacity through the relevant relief device during an overpressure relief?

Edited by fallah, 15 June 2015 - 01:00 AM.

[Zauberberg]

Theoretically - yes, since API 520 provides you with an option to use multiple relief devices with staggered set points. If the total required relief flow can be achieved through multiple devices and you are not violating other constraints (nozzle loads, pressure drop), then you can use this option.

[rajeshrajan]

Thankyou Fallah & Zauberberg for your quick responses.