Incoloy 800HT flange question

[Tuckabag]

Hi All,

I have an application where we are replacing some old equipment.
Our design pressure/temp is 775psi @ 850deg C.
The original equipment was fitted with CL600# Incoloy 800HT flanges.
Can anyone advise if this rating flange is suitable for the pressure/temp requirements? All of my pressure/temp tables only cover carbon steels, duplex and 300 series S/S.
If CL600# is not suited, can you advise if 900# or 1500# are?
Cheers!

 

[metengr]

If you review ASME B16.5, the Incoloy 800HT is not suitable for temperatures above 816 deg C. The maximum pressure for a 2500 Class flange at 1500 deg F (816 deg C) is 230 psi.

Are you sure this is 850 deg C or 850 deg F???

At 850 deg F, a 600 Class flange is good for 975 psig working pressure.

 

[Tuckabag]

Thanks metengr.

Yes, definately 850deg C design temperature. This is for reformer gas application.

According to the data I have, a 316HSS 2500# flange is good for 345psi @ 1500deg F. I would have suspected the Incoloy 800HT to have had a higher rating than 316HSS? We've never worked with 800HT before though so I guess not.

Any suggestions on material we can look at for this pressure/temp requirement?

 

[metengr]

Tuckabag;
I checked again and the N08810 is good for 345 psig, not 230 psig, at 1500 deg F. There is no approved flange material that is in B16.5 to handle 775 psi at 850 deg C.

 

[Tuckabag]

Cheers for the info metengr.
Will discuss with our client and see how they wish to proceed.
Thanks for the advice.

 

[Jmoore1]

Very Interesting....even the superalloys are no where close to your dp at the temperature....sounds like you need refractory lining...how large is this vessel?? You may need to replace with refractory lined ducting for these extreme temperatures.

 

[SnTMan]

Can the flanges possibly be assigned a lower design temp?

Regards,

Mike

 

[Tuckabag]

Jmoore :- The pipeline these are connected to is 24", no details on material of construction or pipe schedule yet..... We are looking to use 50NB flange connections for a sample probe connection, probe to be fitted with a DBB needle valve.

SnTMan :- We are discussing with the client at the moment re the design pressure/temp rating. The operating duties should be OK, 538psi @ 1290deg F, it's just the design rating that is killing us.

Our valve guys are having the same trouble, they cant manufacture a valve to ASME B16.34 for the design duties, but the operating duties are ok.

 

[SnTMan]

It's apparently either overdesigned or overengineered, not sure which...

Regards,

Mike

 

[Jmoore1]

you can refractory line piping of that size quite easily....same with the nozzles and flanges, not sure about valves as I dont know much about them. Ive dealt with a similar issue before (albeit neer atm pressure), you will end up needing refractory for thermal insulation of the steel (this is probably alot cheaper than using an inconel or hastelloy piping as well)

 

[Guest102023]

Each of the 800 variants has its own operating temperature range. Start with the attached document.