80% quality steam and erosion velocities 1

[chemieingineur]

I have looked almost everywhere in order to find recommended erosion velocities for wet i.e. 80% quality steam and have not found much data. What I have found (in Crane and other text books) is that one must design pipes for less than the 100% (saturated) velocities. But Crane and others do not state how much lower.

Of course the best is to have actual pipe thickness monitoring data.

Does anyone have more information?

 

[katmar]

A very good resource for anything to do with steam is

http://www.spiraxsarco.com

Have a look through their recommendations.

If you are genuinely working with 80% quality steam, I would recommend that you start with fixing the separators before you go over-sizing all your pipework to cope with this terrible stuff.

 

[JimCasey]

Second what katmar said.
Separate the condensate from the steam, or reheat it, or do SOMETHING to dry it.

If you are flowing a steam velocity of much less than 100ft/sec (30m/sec) there is a real possibility of slug flow which will lead to water hammer.

Valce manufacturers caution against liquid velocities exceeding 50 ft/sec. Wet steam can cause some nasty erosion because of high velocity droplet impingement.

 

[25362]

For erosion-corrosion have a look at

http://www.steamcycle.com/control_of_erosion_corrosion.htm

 

[TBP]

This sounds like an application in which really crappy quality steam is injected down wells (it's a one-way trip) to liquify thick oil, so it can be pumped to the surface. This is a real niche steam application, and I'm assuming there must be a reason (probably economic) for the 80% quality steam. I don't know of any literature that deals with it - and I've got books on steam & piping that range from recently published to well over 100 years old.

 

[chemieingineur]

Thanks for the information. I should have been a bit clearer on what type of steam line I was referring to. It is a steam injection line for heavy oil production that normally operates at pressures greater than 10 MPa. As such the condensate and steam are never separated ( this is standard operation for over several decades of heavy oil production via steam injection).

I am familiar with the Spirax Sarco website, but the website does not offer information on this type of steam piping. I have also spoken to one of my colleagues at Spirax Sarco and they are not familiar with this type of operation and thus could not offer additional information.

 

[chemieingineur]

Reply to TBP.

I am glad that you confirmed the lack of information on steam injection lines for heavy oil as well. I have looked in almost every text book on steam lines and even heavy oil production and cannot find information on erosion velocities in steam injection lines.

In addition, I could not get any erosion monitoring data either.

 

[EdStainless]

There is an ACOM article published by Avesta concerning droplet impingement erosion, but I belive that only CRAs are covered. And, of course, I can't find a link to it now.

= = = = = = = = = = = = = = = = = = = =
Corrosion, every where, all the time.
Manage it or it will manage you.

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[rmw]

Vacuum condensers have to deal with wet (poor quality) steam and incipient erosion all their life. So do turbine exhausts. Look among some of those resources for guidance.

GE has a good tech info on their site, and HEI might be some help.

So does sugar, so go look around on the

http://www.sugartech.co.za

site.

People that handle moisture in vapor streams might also have info. Try Munters and Koch/Glitsch.

I don't know if any of those places have what you need, and I am not going to go look for you, but if confronted with your problem, that is where I would start.

rmw

 

[rustbuster]

Try

http://www.steamonline.com

they may have something published.

 

[augiedog]

The steam boiler people have guide lines for this I believe Struthers and Thermotics used numbers like rhoV²= 27,000 to 40,000 (SI units) with 5D bends instead of LR els, but the usual safe route is per API 14C which I believe uses a consevative rhov²<=10,000 english units