2.25 Cr-Mo to sustain 1150 F
2.25 Cr-Mo to sustain 1150 F
(OP)
I'd like to specify a Cr-Mo reactor (8 ft diameter) which can potentially see 1150 F @ 50 psig. SO far various info I've found suggests we cannot go beyond 1050 F. Our internal pipe spec however says 2.25Cr-Mo is good up to 1200 F. Can gurus out there give me some advice?





RE: 2.25 Cr-Mo to sustain 1150 F
RE: 2.25 Cr-Mo to sustain 1150 F
An interesting alternative for large dia high temp vessels is to use "ribbon wound" technology, as used in China, as opposed to a monolithic vessel. This might permi use of the W modified T23 ribbons- this would ensure each ribbon was less than 0.5 " thick,which may be neccesaary to ensure a bainitic crystal structure .
RE: 2.25 Cr-Mo to sustain 1150 F
I'm not very familiar with the ASME code. From your reply I take that I can't go for 1.25 Cr-mo for this reactor. Perhaps I should just picked SS304 for this duty
RE: 2.25 Cr-Mo to sustain 1150 F
Have you considered 9Cr material for the pressure vessel ?
In what country will this component be installed ?
-MJC
RE: 2.25 Cr-Mo to sustain 1150 F
I would suggest you revise your internal pipe specification to at least reflect ASME B31.1 Power Piping Code maximum temperature of 1150 deg F.
RE: 2.25 Cr-Mo to sustain 1150 F
I didn't consider 9Cr for this pressure vessel. This vessel will be installed in the US
RE: 2.25 Cr-Mo to sustain 1150 F
The service environment would be about 1100 F @ 50 psi and the process is typical thermal oxidation with NOx, CO, CO2, H2O. Increased oxidation is amongst my main concern in this reactor.
Thanks guys, the info you've provided has helped me to make a good decision. I really appreciate it.
RE: 2.25 Cr-Mo to sustain 1150 F
If the vessel will be installed in the US, I would suggest you familiarize yourself with the ASME B&PV Code. Almost all Jurisdictions in the US require it (at least those that regulate pressure vessels).
Regarding your service environment, I would suspect you will go to a cladded pressure vessel. Probably something on the order of a Ni- base alloy clad weld overlay on a Cr-Mo-V substrate to reduce wall thickness.
RE: 2.25 Cr-Mo to sustain 1150 F
RE: 2.25 Cr-Mo to sustain 1150 F
I fully agree..
MJC
RE: 2.25 Cr-Mo to sustain 1150 F
Being not a guru I suggest you to see figure 5-35 of API RP 571(Nelson Diagram). At 0 Hydrogen partial pressure (which will not be your case) the temperature limit for 2.25Cr-Mo is 1200ºF.With the increasing of hydrogen partial pressure, the temperature limit for the use of 2.25Cr-Mo will decrease accordingly till 850ºF at hydrogen partial pressures above 2000 psi absolute.
regards
luismarques