Multistage RO 2

[process1907]

Hi all,

I'm Nazri
I've 1 question on RO (restriction orifice).

When we need to use multiple (2 or more) RO instead of single RO? Which 1 is prefered?

What is the basis on this?

Thanks.

 

[JLSeagull]

I have only used plates associated with a control valve in a similar arrangement as a multistage restriction orifice. For high gas pressure drop consider a choke.

 

[insult2injury]

Multiple orifices are used to avoid cavitation.

I2I

 

[JJPellin]

Multiple orifices are sometimes used to satisfy API requirements that limit orifices to be no smaller than 1/8". This is an attempt to avoid plugging.

Johnny Pellin

 

[JoeWong88]

Beside cavitation, it is also used to avoid acoustically fatigue failure of pipe.

JoeWong
Chemical & Process Technology

 

[kkimic]

I have seen some RO's with multiple orifices (instead of a single orifice) distributed across the plate, this for high pressure drop. In some other cases we have sized pressure reducing apexes to be fitted in a spool, when the pressure drop required is so high for a single RO that would otherwise cause cavitation. Also remember noise and vibration is always a problem, normally in my experience for pressure drops greater than 3 bar across a single orifice plate, we would normally go for pressure reducng apexes.

Regards.