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1650F and 600 psi - can it be done with metallics only?

1650F and 600 psi - can it be done with metallics only?

1650F and 600 psi - can it be done with metallics only?

(OP)
Ive got a question out of curiosity.
Is it (say hypothetically) possible to design a piping system under B31.3 with design conditions of approximately
1650 F and 600 psi, assuming corrosion resisance is not an issue/required, weldments need to be made and
the system is only made of 'metals' (thus no lined pipe)? The required ID should be some 50 mm.

Or is lined pipe the only way to go with these conditions?

RE: 1650F and 600 psi - can it be done with metallics only?

N08810 and N08811 material have B31.3 allowable stresses listed at 1650°F, you, yes, it is possible.  The allowable stresses are very low, so you'd be into gun-barrel dimensions.  However, it is possible.  There are additional higher-temperature materials not listed in B31.3 that could also give you some strength at 1650°F.

Talk to some specialty materials suppliers.  Materials in the Ni-Co-W family are suitable in that temperature range.

RE: 1650F and 600 psi - can it be done with metallics only?

(OP)
Hi TGS4, thanks for the comments.
I knew N08800/-10/-11 had some impressible allowables, I think even the highest from B3.3.
However, the required pipe size would become some NPS 3 XXS or higher schedule. (not even thinking bout market availables).

The flange class rating would be (far) beyond B16.5 cl 2500, so my feeling tells the High Pressure piping chapter rules might be a
better place to got for the pressure design pipe wall thcikness eq.
Also, the estimation of the W factor for the weld joint strength reduction is difficult; in my first attempt to estimate it, it went to around 0,1 I think.

The max I could find with N08810 was less than 145 psi @ 1650 F; not even close.

RE: 1650F and 600 psi - can it be done with metallics only?

You're even beyond the limits of Grayloc connectors at those conditions.  

Can it be done?  With a limited design life and LOTS of design effort, I'd imagine it can be done.  

Should it be done?  Probably not.  Most equipment operating at those temperatures is done using internal refractory lining. It takes care just to ensure that alloys survive their own self-weight long term at those conditions. You're in the region of active creep, so failure is only a matter of time.

From what I've read, there are steam reformers operating in that temperature range and even beyond it, but they operate at lower pressures.  They do not have flanges in the regions at those temperatures, and they make use of centrifugally cast materials for the reformer tubes.

RE: 1650F and 600 psi - can it be done with metallics only?

(OP)
Hi moltenmetal, thanks again for your contribution. Something tells me where in the same business :). Your reply was the kinda discussion I'd like to get.

From other discussions Ive gotten into, the feeling arose these kind of conditions arent just met by making a simple pipe spec from B31.3 allowables and listed values.
B31.3 provides some insight to what is possible with listed values, but the design for creep, bolted joints/flange connections etc.,
weld joint strength reduction, creep considerations, decreased creep strength with fatigue and increasing cyclic behaviour, failure modes,
corrosion resistance and economics quickly shows this is something out of the box for standard metallic piping.

Refractory lining is a good place to go. Any suggestions for refractory material, refractory thickness, and shell MoC?

RE: 1650F and 600 psi - can it be done with metallics only?

The latter part of your question is a little like asking "how long is a piece of string"?

If you're asking for the correct refractory material for use inside a fired steam reformer tube, the answer is "none, because the process is endothermic and you need to absorb heat THROUGH the pipe wall for it to work".  Hence metallic systems are the usual solution, tough as they are to implement and maintain.  The only economic solution is to eliminate flanges (i.e. weld everything together), use non-code materials or code materials beyond the code SAS limits (i.e. based on rules other than the code), and to limit your pressure.

The other solution for reforming operations is to use the autothermal reformer approach, which many companies do.  This comes with costs and benefits.  Both SMRs and ATRs are built commercially, depending on the application and scale.

If you need a refractory internal lining system merely to resist 1650 F in a 600 psig line, there are many options.  Shells are usually carbon steel and the shell is usually fairly hot even when the lining system is new and undamaged.  Heat losses are significant and inevitable.  Which system is right for you depends on many, many factors, not least of which include the permissible heat losses, required inner diameter, tolerable gas permeability of the refractory system etc.  It's beyond the intent of a forum like this to answer that for you.

RE: 1650F and 600 psi - can it be done with metallics only?

(OP)
Thanks again moltenmetal  

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