Material selection for refinery instrumentation

[RofiqNur]

Dear Netters

I am doing with refinery project in Malaysia, I have one issue regarding material selection for control valve and pressure safety valve, special for trim area.

In refinery plant we have process service of C4 hydrocarbon, butadiene, solvent etc which will be relieved in relieving temperature of over than 150 degC. the questions are:1.
1. is whether corrosion cracking occur for these fluid in high temp?
2. if so, is only duplex SS suitable for the trim vavle (nozzle, disc)?

Thanks for your kind input.

best regards
Rofiq Nur

 

[weldstan]

Not enough information. Is there wet H2S, caustic, amines, etc. in the stream?

 

[RofiqNur]

hi Weldstan

the information I have is only the service is C4 hydrocarbon and crude butadiene with no NACE requirement involved. Imply this I don't think H2S and caustic condition necessary to be considered.
if so is it meaning that no corrosion cracking on high temp will occurs?

thanks with regards
Rofiq

 

[moltenmetal]

Unless there's an aqueous component you're not mentioning, normally people would use ordinary austenitic stainless steels for trim materials in such a service.

 

[TVP]

I agree with moltenmetal. Unless there are additional species (see weldstan & moltenmetal comments), this should not require more than conventional austenitic stainless steel.

 

[weldstan]

Assuming that the pipe is carbon steel, carbon steel valves with 316 trim should be acceptable.