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Which kind of PWHT for tank with KOH, HF, hydrocarbons 2

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MichaelDexter

Mechanical
May 26, 2014
31
Hi
It is possible, that I will make design of horizontal pressure vessel with boot for potassium hydroxide (KOH), hydrofluoric acid (HF), hydrocarbons.
It is a reconstruction design, old tank has more than 40 years. The tank is made from SA-515 gr 70, and had a post weld heat treatment.

Do you know what type of pwht / stress relive should be used for this type of fluids ?
I think, that stress relive is applicable

New tank will be made from European material P265GH or P355GH (P355GH is near equivalent of SA-515 gr 70)

Thanks for any advices
Michal
 
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The fluid(s) won't determine the PWHT, the Construction Code will. Regardless of the tank being a reconstruction, the current code edition (or the one accepted by the jurisdiction) will have to be adhered to.

The basic location of holes and other dimensions can be used in the design. The thicknesses, material selection, welding, PWHT, and any NDE will all have to be per the most current construction code.

Quality is not an act, it is a habit - Aristotle
 
Fluid(s) can and do determine PWHT. It's just that ASME construction codes (which are not design manuals) do not address it.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."
 
My mistake. Appreciate the correction!

Quality is not an act, it is a habit - Aristotle
 
MichaelDexter,

You will want to PWHT this material at 1150-1200F for 1 hour per inch of thickness, 1 hr minimum. Source is API RP582 for HF acid service.

The devil is in the details; she also wears prada.
 
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