Flow Accelerated Corrosion

[Judoka]

Does anybody have information that can assist in determining the flow accelerated corrosion rate of Carbon Steel Pipe (SA-106 GrB) with clean deaerated boiler feedwater? What are the rule of thumb velocity limits to prevent FAC of a CS pipe? Can anybody suggest any good sites or literature with FAC rates?

 

[countryham]

Yes,I have the answers to your question.I have been researching ,this 50 year old known corosion problem for a very long time.However, I don't know whether I am allowed to give you the solution (I have the patent pending)or not. You maybe aware,this problem has been traced to catastrophic explosions on several occasions and cost the lifes of numerous people.I can tell you this,....I think!...The cause must be corrected according to your metaluragy and chemical kinetics before water exits the deaerator.You can bet that even though you may have a deaerator that is producing 7ppb or less under designed conditions,it will still produce hi values, even if you have an oxygen scavenger in the exit water.You must control dissolved oxygen within 1-2ppb.EXITING THE DEAERATOR-A tall order when you intend to carry an oxygen scavenger residual in the boilerwater....Also,if you have mixed metalurgy,say,copper alloy in feedwater heaters, you can not have greater than 1ppb dissolved oxygen in the feedwater

 

[Lovison]

I have no patent pending but I do know that velocity is a key factor. What are the velocities you are currently running at? Is one area more susceptible than another?
Has this problem been ongoing or just recently discovered?
Has the process been altered - chemically or more heat been introduced?

Wayne E. Lovison
service-parts@naglepumps.com

 

[MJCronin]

Guys....Guys...

As an old powerplant systems designer, I recall a couple of rules of thumb about condensate systems:

- Keep the design velocity at 3-7 fps

- Use sched 80 pipe and replace the system as necessary

Check in the "Piping Handbook" by NAYYAR... I believe that there is a table of maximum suggested velocities for various piping systems, including condensate.

I belive that EPRI (Electric Power Research Institute) has authored many papers on this subject. They also offer a proprietary program (called CHEKMATE, I believe) that will investigate and evaluate specific sites suspected of FAC.

However, EPRI is funded by the utilities and publications are not free...

Condensate systems, like love, periodically erodes away and needs replacement every 15 to 20 years....

Anybody got any research papers/websites etc. to share ??

Hope that this helps....

MJC

 

[stanier]

Nalco put out atextbook on corrosion in boiler systems that may have data the that you seek. Of course they will want to sell you chemicals. They do have a large R&D effort throughout the world.

 

[countryham]

As I said earlier,I may get in trouble giving you the answer to this problem because it is resolved by my patent and corrobated research of others.It would take my presentation of about 6-8 hours (applied physicochemical kinetics) to convince you (as well as everyone else) that the problem is solved---guaranteed-- 24/7 regardless of inevitable mechanical malfunctions within the deaerator that can rapidly cause damage throughout the steam/cycle circuit......however,...since I am reluctant to get in trouble, I suggest that you read a pretty darn good article by Dr. Otakar Jonas entitled: PLANT ALERT -Don't let erosion/corrosion compromise safety----In POWER,FEB. 1996,p38-39.....You can consider Dr. Jonas an authority...He has written other very good articles ,as well

 

I agree with M J Cronin, the Electric Power Research Institute funded extensive research to develop and validate the erosion/corrosion computer program. The program was applied to a large number of Nuclear and Fossil fueled power plants in the late 1980's. The EPRI program manager, in 1987 was Bindi Chexal and the program was identified with an extraction of his name. My files are archived but recommend do an internet search or contact EPRI in Palo Alto, California. Bob