What is the best material for boiler tubes - Stainless or Titanium?
What is the best material for boiler tubes - Stainless or Titanium?
(OP)
I have a small diesel boiler, with steel coils which only last 12 months. If I change the material, which is best Stainless 316 or Titanium GR2? Or do any of you have any other recommendations? The tube size is 20mm, working pressure is 350Bar at 90 Deg Cel. Thea pplication is hot water for a high pressure water cleaner.
Thanks
Thanks





RE: What is the best material for boiler tubes - Stainless or Titanium?
Is your burner working properly? What is the failure method you're seeing?
I worked on a firetube boiler that had excessive corrosion b/c the hot gases were being cooled too much in the tubes and the HCl was condensing out of the gas. We recirculated some of the hot water back into the return to raise the temperature of the return water and it reduced the corrosion rate.
I don't think your boiler is firetube, I'm just trying to say that there are other, possibly better or more economical, approaches to solve these problems other than simply paying for upgrading the material.
RE: What is the best material for boiler tubes - Stainless or Titanium?
But if you can't do anything with your water source,
you might want to go with duplex 2205 SS or 904SS
RE: What is the best material for boiler tubes - Stainless or Titanium?
Does your hot water contain chlorides? If so, stainless is not a good solution. You might consider copper or bronze tubes. Titanium just seems a bit much for this application.
Patricia Lougheed
******
Please see FAQ731-376: Eng-Tips.com Forum Policies: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.
RE: What is the best material for boiler tubes - Stainless or Titanium?
RE: What is the best material for boiler tubes - Stainless or Titanium?
You might try recirculating hot outlet fluid back to the inlet so as to ensure a minimum mass flow rate in excess of 800,000 lb/hr/ft2.
The low temps do not imply an upgrade beyond carbon steel. However, there is a canadian boiler vendor that uses incolnel for their once-thru steam generators , to allow "dry firing" operation. If your unit must also be suitable for "dry firing" or you cannot adequately control the flow + firing rate, then a similar upgrade to ilcolne may be considered.
RE: What is the best material for boiler tubes - Stainless or Titanium?
If it blows up and kills someone, it is the responsibility of the designer and builder of the unit (and you as the rental agent to some minor extent - I hope you are insured).
But if you redesign it, choose a different tube metallurgy, change the design in any way, put it back together and then it harms someone, you are on the hook all the way.
The original Mfg'r will disclaim any responsibility and you (or your insurance company) will be exposed to the max. You just bought the farm.
I'd run from any idea of modifying this in any way and just figure the cost of maintenance or replacement in your rental rates.
Check with your insurer before proceeding.
Good luck.
rmw
RE: What is the best material for boiler tubes - Stainless or Titanium?
Be careful when using 2205 duplex stainless. There is an upper temperature limit of 600F
This limit imposed by the ASME code is to prevent long term embrittlement in usage.
http://w
Look at 904 and possibly 317 LMN stainless.
Get rid of the chlorides !!!
-MJC
RE: What is the best material for boiler tubes - Stainless or Titanium?
The worst idea was of welding the coil tube loops between each other not allowing any flexibility for thermal expansion.
Stainless is not a good solution.
I would consider 254SMO. It is not sensitive to chlorides, and has a quite high allowable stress upper temp. limited to 750°F
RE: What is the best material for boiler tubes - Stainless or Titanium?
RE: What is the best material for boiler tubes - Stainless or Titanium?
Figure out what is happening.
RE: What is the best material for boiler tubes - Stainless or Titanium?
I cut a faulty section of a coil out to see there / how it failed. It failed on the bottom coil where the baseplate was welded onto the coil. The inside of the tube (at the bottom )was corroded quite badly, and it failed at the weakest spot, which was the weld. There are always water left in the coil, so i assume it will always be an issue with CS? What are your opinion on Shmulik's surgestion of 254SMO?
RE: What is the best material for boiler tubes - Stainless or Titanium?
RE: What is the best material for boiler tubes - Stainless or Titanium?
RE: What is the best material for boiler tubes - Stainless or Titanium?
RE: What is the best material for boiler tubes - Stainless or Titanium?
RE: What is the best material for boiler tubes - Stainless or Titanium?
RE: What is the best material for boiler tubes - Stainless or Titanium?
Kalen Smith
Engineer-a-Business
http://www.engineer-a-business.com
RE: What is the best material for boiler tubes - Stainless or Titanium?
RE: What is the best material for boiler tubes - Stainless or Titanium?
RE: What is the best material for boiler tubes - Stainless or Titanium?