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Water washing 316 valves

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sadsack5000

Petroleum
Apr 13, 2016
4
Gents,

First time posting here so please be gentle
I have a valve which has been taken out from a clean propane gas service for inspection purposes. There is no corrosion but a mechanical failure upstream has left the valve covered with debris and dirt. Operations would like to water wash the valve using plant demineralized water before returning to service.
Valve has 316 body and operates around 40-50oC.
My fear is that the demin water may contain enough chlorides to cause chloride pitting corrosion when returned to service.

What precautions should be taken to water wash these valves?
What chloride content is acceptable for a demin water wash? I am seeing 50ppm and 100ppm max in API 510 and API 598 respectively.

Thanks
 
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Anything below 50ppm should be plenty clean. Though washing and drying is the easiest, after all you don't want any water back into your system.
Will water clean it or will you need detergents or solvents as well? Either way make sure that it is dry (even inside) and you will be fine.

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P.E. Metallurgy, Plymouth Tube
 
Ok thanks Ed. Is there any guidance note/standard on water washing of pressure equipment that you know of? for example in shutdown and the internal walls of a vessel/exchanger need cleaning down to allow inspection?
 
Demineralized water by definition is free of chlorides.
 
You never know how good peoples water is.
It is best, and easiest to monitor conductivity, as long it is less than 4 microS (resistivity greater than 25MOhms) you should be good.

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P.E. Metallurgy, Plymouth Tube
 
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