High temperature application material 3

[asv80]

We have a high temperature heat exchanger application and would like your comments on material selection. The mean metal temperatures is about 1540°F. We are trying inconel as a material and find we get very thick tube sheets. If anyone used materials around these temperatures please give your comments.
Thanks in advance.

 

[unclesyd]

asv80,

I think you have to sign on (free) then you can get access to the shared album. The album is named "tubesheet" and the password is "insulation"
I'm trying to find out if that is the correct way.

 

[asv80]

unclesyd:
I got a username and password. There is a tab to view friend's shared with friend's username and password. I tried tubesheet/insulation but does not work.
Thanks

 

[unclesyd]

The album is under unclesyd38 password et2005

 

[asv80]

unclesyd:
thank you very much. I was able to look at the pictures.

 

[unclesyd]

This bundle is a later model where the insulation at the tubesheet is boxed in and not open to the process. The bundle is a tight fit in the shell. When it is inserted if needed there is a layer 2600°F ceramic wool wrapped around the insulation box close to the tubesheet and tied with Inconel or 310 wire. There is still some hot gas circulation in this area as the whole shell is boiler. This is done to keep the temperature gradient within bounds on the shell and flange.

The shinny insulation covering is used to help keep the exit process gas in the tubes from getting too hot. The gas entering the tube bundle at the perforated plate is in the range of 1500°F - 1750°F. The isulation doesn't cover the entire bundle. The boiler generates 650 psig steam @ 750°F

 

[asv80]

unclesyd:
thanks for the added information.

 

[unclesyd]

One added piece of information this is one of the bundles made in our Fab shop. This bundle has just been refurbished at a local shop under our supervision.

The inlet gas nozzle coming through the visible tubesheet exits at the inside tubesheet. All the expansion is taken up by an bellows seal at the inside tubesheet.

 

[rorschach]

There is an article in this month's Advanced Materials and Processes magazine on high temp alloys written by Richard Frank of CarTech covering their Pyromet and Waspalloy age hardened series of alloys. just perusing the tables shows the following as possibles from a retained strength point of view, corrosion will be another issue and you might want to consult with Cartech for particulars:
Pyromet 80A 41 ksi at 1600 F
Waspalloy B 75 ksi at 1600 F
Waspalloy A 76 ksi at 1600 F
Pyromet 41 78 ksi at 1600 F
Pyromet 720 109 ksi at 1600 F


Mind you these alloys are not cheap by any stretch of the imagination and they may not be available in tubing. Your milage may vary.

 

[asv80]

rorscharch:
Is it possible to get the article?
Thanks

 

[asv80]

unclesyd:
thanks for your insights but unfortunately the is project dead from our end. But, now I know a starting point to look in the future. Also, can you let me know who constructed the unit.
thanks for your efforts.

 

[unclesyd]

You need to contact Dr. Jack Sparks at the following company. They are quite familiar with the construction of insulated tubesheet exchangers.

http://www.serfinc.com/index.htm

 

[asv80]

Thanks unclesyd.

 

[rorschach]

If you want a copy, I'm sure CarTech would be happy to give you a reprint. If you are an ASM member, you can download the article from ASM's website in PDF format.