how can i reduce pressure in a liquid ?

[dhnsekaran]

Dear Sirs,
I want a clarification regarding to reduce the pressure in a pipeline flowing water in high pressure,
Yes, Am having a High temperature (100 deg C), High pressure (150 Barg) water flowing in a pipeline,
I want to use it for my well annulus heating with reduced pressure as 40 Barg,
If I go with multiple Restriction orifice pressure reduction method, is there more noise will be?
Please anybody suggest available methods?

Thanks and regards,
Dhnssekarn

[polaris44]

use control valve

[carlo.stenali]

yes, turbolence within restriction orifices or valves would produce noise but that could be acceptable (for example you can enclose parts within some sort of barrier etc.), if flow is high you may also consider the possibility to recover enregy , you should be vary when evaluating the different systems available as these depend from specific application.

[EHGebesy]

For the restriction orifice you have to calculate the cavitation index first
If cavitation index higher than 0.93 then single stage RO will be sufficient, other that you have to proceed with mulitstage.
Cavitation index is a check point related to (the vapor which formed the noise predition dba.

The second solution is to size a pressure control valve (equal perecntage% as a charactarstic & it's strock opening% could be as 95%)

I hope my submitte valuable for you.
Regards,
Emad Gebesy
Worley Parsons
emad.gebesy@worleyparsons.com

[TOLGAUS]

use multiple hole orifices in series and drop the pressure in multiple stages. it needs a little bit detailed engineering but in this way you can minimize the cavitation and accompanying noise. My collegue designed a skid like this recently which dropped the pressure of water from 220 barg to almost vacuum (feed T: 20 - 30 C & flow: 15 -35 m3/hr) for the purpose of preventing erosion of choke valves and downstream piping during a start-up of a new converted offshore water injection (WI) well. The results were positive and now we will try the same unit on another WI well. Your biggest problem is the 100 C. This can be your showstopper. Make your calcs very carefully to prevent any unnecessary steam flashing which will cavitate all your orifices leading to excess noise and defficiency. Use a sort of cooling unit if you have the sources otherwise try to cool down the water with ambient. This will cost you for sure.