How Much Oxygen to Damage a Locomotive Boiler

M Austin · **Joined:** Sat Feb 05, 2005 1:05 am **Posts:** 488

The Lahaina Train on Maui provided almost laboratory conditions to determine rate of boiler damage due to lapse in CONSTANT water treatment.

The Anaka's boiler was built in 1988 and had been in almost constant daily service except as noted below. While working as a State Boiler Inspector, I regularly conducted internal inspections on this boiler. Due to the reverse osmosis and hydrazine treatment, I have washed boilers and left more mud than would be found after a years operation. Another interesting observation is that when in daily continuous service the waterside surfaces showed the black magnetite patina typical of powerplant boilers. As seen in the photographs, once the problems started, the surface color changed to the red rust hematite flavor.

As described, the amout of oxygen saturated water was about 1 tankful every 3 weeks for 3.5 years @ 1200 gallons per tank. 65 X 1200 equals approximately 78,000 gallons. (Or in relative terms, 3 tender tank fulls on the UP 844 @ 25,000 gals.)
Unless the water chemistry is No. 1 priority in locomotive operation, serious analysis of other failures is futile.

tomgears · **Posted:** Mon Jun 14, 2010 8:36 am

Thank you for sharing. Very interesting commentary and photos to say the least. I was a little surprised to hear hydrazine was being used. Most water treatment people I have known have been anti-hydrazine due to it's toxicity.

J.David · **Posted:** Mon Jun 14, 2010 11:17 am

Dear Matt:
Thank you for sharing your (as always) informative photos and analysis.
A couple of questions:
I wasn't aware that the black magnetite wasn't permanent. Am I correct in asuming then, that if you want a continous magnetite coating you must use a treatment like Hydrazine or DeHa continuosly?
Second is there a "term of art" to describe the stress accelerated corrosion as found in "ANAKA"?
Third, what is your opinion as to why the stays corroded and not the adjacent sheet?
Lastly, were these stays supposed to be full penetration welded? If so, I see no trace of penetration into the water side.
Thanks again!
J.David

softwerkslex · **Posted:** Mon Jun 14, 2010 2:52 pm

We visited in 2005 and just happened to witness the power changeover, so I assume the repairs were made. Is the solution to store the engine dry, draining the tender and boiler?

M Austin · **Joined:** Sat Feb 05, 2005 1:05 am **Posts:** 488

J.David,
In reverse order for ease of answering:

J.David wrote:

Lastly, were these stays supposed to be full penetration welded? If so, I see no trace of penetration into the water side.

While most steam and boiler mechanics state, "It's not rocket science" that is only because they perpetuate the sledge hammer mechanics and weld techniques that thrived and were passed down from the late 1950s while the roundhouses were in the "Get it out for one more trip mode". Note the tube sheet weld. Do you see a start or stop? Any undercuts? Any grind marks to dress up sloppy welds. Peruse a few web sites of current "Professional" loco boiler shops, look at the welds evident and judge how many have a crown exceeding 3/32".
Anaka's boiler was built by Western Metal Products operated by King Frey. He was a real rocket scientist, Hughes, Northrup, mostly "black" projects, and also taught occasionally at some SoCal universities. King and his son were certified to weld TIG, MIG and stick. You don't see big blobs of 6010 hanging from the roots of the staybolts because the staybolts were all TIG welded flat with a 1/16" root with a feather bevel.
Roots of the staybolts look pretty much like the roots I see on 0.180" wall 2" OD waterwall tubes in powerplants. King's son was very proud of his ability to run a 14 ft long MIG fill pass without a blemish.
I personally get infuriated when steam professionals make claims such that "in the real world it doesn't happen that way". An acceptable cop out would be, "I can't do it that way."

J.David wrote:

Third, what is your opinion as to why the stays corroded and not the adjacent sheet?

Please refer to figure 1. Sheet corrosion WAS excessive. (Not enough coffee in the early morning, J.D? :)

J.David wrote:

Second is there a "term of art" to describe the stress accelerated corrosion as found in "ANAKA"?

In most engineering circles it is just called stress corrosion until it causes a crack and then it is called stress corrosion cracking. All boilers have areas of localized stress. Without oxygen there is no corrosion. As noted, it does not take inordinate amounts of oxygen to produce inordinate amounts of corrosion.

J.David wrote:

I wasn't aware that the black magnetite wasn't permanent. Am I correct in asuming then, that if you want a continous magnetite coating you must use a treatment like Hydrazine or DeHa continuosly?

Terlyn and their LBS treatment is a chelating boiler treatment that can be bought from any treatment company. All the statements that they make in their literature is correct for its design application of copper nickel heat exchangers in submarines. The oxides of copper nickel are tenacious and protect copper nickel from further corrosion in seawater. The contention that boiler steel forms black magnetite when cleaned of scale and exposed to oxygen and never rusts again is outright invalid. If that were true no steel boiler would ever need oxygen scavenging water treatment. Agreed?
The Aloha Stadium was built of Corten steel with the promise that after a few rains the protective coating would form and they could save $10M by not having to paint it. Within 10 years they were into an $80M corrosion remediation and painting program. Yes, flat pieces that were exposed to rain protected nicely as advertised. HOWEVER, anywhere the water could channel, there was a problem. The same flowing water that carved the Grand Canyon, also flakes off magnetite protective oxides, exposing fresh, delicious, naked iron atoms to unscrupulous, soulless oxygen atoms.
The test bed for the Terlyn treatment was Georgetown Loop. Rocky Mountain spring water has lower saturation of oxygen due to the elevation and lack of oxygen even for breathing. Plus there is high probability that any particular gallon of Silver Plume water was virgin snow within the last week, with little exposure to air. Has no one pondered the extraordinary boiler longevity of the Rio Grande narrow gauge locomotives? What fountain of youth well do those locomotives drink from?????

Most of the "magnetite coatings stop corrosion" blanket statement legend has been perpetuated by Terlyn in their LBS literature. I have seen no other chemical company literature make this claim and Terlyn provides no second party substantiation.

J.D, the short answer is minerals and oxygen are two different completely independent entities. Both have to be treated separately. There is no one chemical snake oil that does it all.

M Austin · **Joined:** Sat Feb 05, 2005 1:05 am **Posts:** 488

tomgears wrote:

I was a little surprised to hear hydrazine was being used. Most water treatment people I have known have been anti-hydrazine due to it's toxicity.

The Lahaina Railroad has since changed to DeHa. The chemical company that serviced the RR came and replaced the hydrazine bottles as needed. All the railroad did was fill the water softener that pre-treated the RO unit. There was a feed of sodium hydroxide to maintain the pH in the preferred 9-11 range. Except as noted the boiler guts were immaculate.
Hydrazine is N2H4. Ammonia is NH3. Both carry the Health Level 3 safety warning. I did read that one guy died after being exposed to sub-lethal levels for several days. It is also described as a known carcinogen. (As is saccharin).
I believe it became inconvenient not for the health hazard as much as the rocket fuel aspect liability, the need for special handling and regulated storage.

crij · **Joined:** Sun Aug 22, 2004 12:15 am **Posts:** 585

Since the boiler is mainly closed off to atmospheric oxygen when cold, I wonder if you would have saved a bunch of headaches by storing the tenders dry, and refilled when you restart a locomotive. This would almost eliminate the problem of the hydrazine absorbing oxygen from the air and supersaturating the boiler water when in storage.

Does Deha have the same problem as hydrazine as far as being able to supersaturate water with oxygen?

Rich C.

Dave · **Posted:** Tue Jun 15, 2010 1:09 pm

Reading between the lines, it sounds to me as if in many cases of infrequent use, when it comes to water treatment the solution is actually the problem........or at least what is in it.

Wish I had paid more attention to what exact chemicals we used - but we were hot for a month at a time between between washouts and cold and dry otherwise. We varied the quantity of chemical added (and blowdown schedule) depending on that days test results of both feedwater from the tank and hot water sampled direct from the boiler. Results using this strategy were good during my tenure- previous strategy was having the company that sold us chemicals also do infrequent testing which always seemed to lead to a requirement for more use of their product line. Having a disinterested third party lab come in and set us up with a test program and occasionally look over our shoulder with no other agenda might work for others as well.

dave

M Austin · **Joined:** Sat Feb 05, 2005 1:05 am **Posts:** 488

.

NALCO literature on oxygen scavenging.

.

Dennis · **Joined:** Sat Apr 10, 2010 7:06 am **Posts:** 35

Somewhere I have a Marine Safety Notice regarding the use of Hydrazine.
Where I used to work used Hydrazine as its oxygen scavenger until the above safety notice came out revealing all its nasty side effects to humans. We changed to a Tannin based oxygen scavenger in our two industrial water tube boilers.

060 Hogger · **Posted:** Wed Jun 16, 2010 7:36 am

Magnetite films do minimize corrosion. They are not the cure-all or end-all forever.

The film must be maintained and protected.
This requires consistent and ongoing use of an appropriate chemical treatment.

Cold wet, or damp, layup of a boiler is simply setting-up damaging conditions, unless done properly.

It isn't that Hydrazine, or any chemical oxygen scavenger, " super saturates " with oxygen. The water simply becomes saturated with atmospheric air and it's 20.8 % oxygen. It is more that it is no longer effective, like a sleeping sentry at the gate, and allows the oxygen in to do it's dirty work.

Oxygen scavenger applied to water standing in a tender or any open tank will be negated, destroyed, made ineffective. ( a lid does not, for chemistry purposes, constitute ' closure ' ) What also occurs is that the depleted chemical contributes to TDS, foaming and carryover, and galvanic corrosion.

For that matter, a boiler typically isn't " closed ". Atmospheric air can typically breathe in and out through leaky valves. This exhausts the chemical oxygen scavenger in the boiler. Regular recirculation, chemical testing and renewal as necessary, of the oxygen scavenger and other treatment applied are absolutely necessary. Other chemical treatment is necessary. No chemical oxygen scavenger will protect steel unless the pH is adjusted to at least 9, better 10.5 .

Nitrogen blanketing to protect a boiler in cold wet layup is common in industry and utilities.
It is time that railway and steam preservation in general catch up with this.

To be effective, it must be applied as the boiler is cooling down, the water is still deaerated, and before the boiler goes into a vacuum. Only a slight pressure above atmospheric is necessary, and it need not be maintained continuously. Once the boiler cools down, only a weekly 15 minute maintenance purge is necessary.

Newriver400 · **Posted:** Wed Jun 16, 2010 9:42 am

Dave wrote:

...previous strategy was having the company that sold us chemicals also do infrequent testing which always seemed to lead to a requirement for more use of their product line. Having a disinterested third party lab come in and set us up with a test program and occasionally look over our shoulder with no other agenda might work for others as well.

dave

That's kinda my thoughts. I know we had a similar experience at TVRM some years back. At one point the treatment levels were so high that foaming was a constant problem. My own experience was leave out the treatment for a day and the foaming problem went away like magic. Then keep the treatment at reduced levels and no foaming. As for the chemical analysis, I'm not sure about the science there, but the chemical man always called for more or different treatment. He didn't have to fire and operate the locomotive or he may have had a different take on the amount of chemicals to add. A friend who works with stationary boilers for a living and plays with traction and locomotives for fun was always of the opinion that a good oxygen scavenger was the primary need and that the chemical man's job was to sell more chemical.

Dave · **Posted:** Wed Jun 16, 2010 11:32 am

I'm nothing like a chemist and can't explain what we used, why and how it worked - but our setup was so basic any reasonably intelligent person willing to take the time could do it: take samples here, process them according to this recipe, and if this is the result do this and if the result is something else alter accordingly this way. Occasional oversight by the vendor lab to make sure we were doing the job properly, and overall conditions hadn't changed requiring changing the process were critical for long term workability.

I'd venture to suggest the cost of the program was more than paid for in terms of lower chemical costs, doubling our time between washouts, and deferred corrosion problems down the line. Helped that the lab guy thought steam railroading was way cool and brought his kid out for a cab ride.

dave

060 Hogger · **Posted:** Wed Jun 16, 2010 2:06 pm

Newriver400 and Dave,
Your observations are right on. When I was water chemist at Harrisburg, PA Steam Works ( now NRG ), our consultant did not sell the chemicals. He simply had our best interests in mind and performed the consulting service.

Some time afterward, I interviewed for a position as a Local Service Rep. for a well known industrial water treatment company. The District Manager, interviewed me first and liked me. The next interview was a week or so later, by the Regional Manager.
He said, " You'll never make it in this business. You want to help people solve their problems. That's not our job. Our job is to sell chemicals. "

That, my steam friends, is one of the major problems we have to fix in this business.
The Saturday Locomotive Mechanic, sometimes the Chief Mechanical Officer, do not have the time, background, staff and resources to also follow up on the water treatment. Ironically, there is precisely where some of the greatest savings can be achieved, not only in the initial cost of the ( over ) treatment, but even more in the damage done by poor or ineffective treatment. Clearly, everyone needs to get sharp and stay sharp on this. Also, the target is moving, technical changes have made it a different world of possibilities that were not even available in 1960, let alone 1890 to 1920. We don't have to put up with crapped-up boilers or expensive treatments that do a poor job at best.

060 Hogger · **Posted:** Sat Jun 19, 2010 8:55 pm

M Austin wrote:

J.David wrote:

I wasn't aware that the black magnetite wasn't permanent. Am I correct in asuming then, that if you want a continous magnetite coating you must use a treatment like Hydrazine or DeHa continuosly?

Terlyn and their LBS ( sic ) treatment is a chelating boiler treatment that can be bought from any treatment company.

Not quite true, it is not a " Chelant ", comparable to EDTA or NTA, It is more of a surface active protective film former. It, and simlilar products, like Helamin ( Switzerland ) clean by breaking the bond to the host surface and to other adherent deposits. In a mechanical sense imagine popping the shingles off a roof with a V - notched shovel. It has a crystal growth modifier ( acrylic hydrate ) that takes the sharp interlocking barbs off calcium crystals and rust flakes. The scale can no longer bond to itself or a host surface. The molecule-thin Acrylate polymer film that is formed on the base metal protects the base metal.

All the statements that they make in their literature is correct for its design application of copper nickel heat exchangers in submarines. The oxides of copper nickel are tenacious and protect copper nickel from further corrosion in seawater.

Copper Nickel heat exchangers are not used with treated water systems, that is the reason they are constructed of this material. My background includes being Engineroom Supervisor on USS Sculpin, SSN 590. Please show us the literature where these statements were made, and I'll believe that they were made.

The contention that boiler steel forms black magnetite when cleaned of scale and exposed to oxygen and never rusts again is outright invalid.

See Below please, where this is more fully addressed. It is more than Magnetite, but Magnetite Hydroxide, formed under consistent basic chemical conditions. Part time or sometimes, if we happen to think about it, just will not make it in this realm. It takes dedication and consistency, a desire and moxie to make it right and keep it right. It isn't impossible, and it isn't complicated.

Not sure that these contentions were made or inferred. Did either Bill Bondie of Iron Horse Water or Terlyn Industries itself ever state to " ...use this treatment once, or for a little while, and all your boiler corrosion problems will disappear forever ... " No, should they have stated that continued protection is dependent upon continued use, i.e. maintenance of the proper chemical enviornment, pH 10.0 or above and low dissolved oxygen. That would be more in-line with the principles of chemistry. p.s. Look out for that coffee from the drive-through, it's HOT !

If that were true no steel boiler would ever need oxygen scavenging water treatment. Agreed ?

Of Course steel needs protection from oxygen attack, however,
the problem is mostly during layup, not steaming. Cold water simply holds 7 Parts Per Million ( PPM ) of dissolved oxygen, Steaming water, where the incoming water's burden of dissolved gases is allowed to escape promptly from the boiler or deaerating feed tank, holds 40 Parts Per Billion. Adding a chemical oxygen scavenger to the feedwater of a steaming boiler is futile, however. The chemical is continuously overpowered by the incoming oxygen. The resulting product simply contributes to
Total Dissolved Solids ( TDS ), unnecessarily promoting
( 1 ) water carryover with the steam,
( 2 ) galvanic corrosion due to the high conductivity of sulfite / sulfate,
( 3 ) converting a benign soft sludge that is hydrated ( holding water ) and flows easily, into a hard honeycombed scale. This is because calcium carbonate will convert to calcium sulfate, gypsum, the binder in concrete.

No matter what chemical treatment you use or don't use, nitrogen blanketing in wet layup or full dry layup are the industrial and utilities' standard for boiler protection. Cold wet layup is not layup at all, but abuse of equiment, setting up slow destruction.

The Aloha Stadium was built of Corten steel with the promise that after a few rains the protective coating would form and they could save $10M by not having to paint it. Within 10 years they were into an $80M corrosion remediation and painting program. Yes, flat pieces that were exposed to rain protected nicely as advertised. HOWEVER, anywhere the water could channel, there was a problem. The same flowing water that carved the Grand Canyon, also flakes off magnetite protective oxides, exposing fresh, delicious, naked iron atoms to unscrupulous, soulless oxygen atoms.

Let's compare apples to apples here, not apples to oranges: rainwater falls with a natural pH of 6.4, maximum, due to the Carbon Dioxide and Nitrogen in the air. Add some modern air pollution, sulfur and nitrogen oxides, and the pH will be down near 4.0 . I have measured that in wells in southeastern Pennsylvania. Apparenly, no one at Aloha Stadium was maintaining the proper chemical enviornment. We, in our desire to get the best service, preserve historic artifacts, and incur the lowest possible operating and maintenance costs, wouldn't abuse our boilers by using Acid Water, repeated oxide film formation then scrubbing that protective film off. We would be as consistent in our treatment as possible. Drastically changing chemical conditions leads to destruction of protective films.

The test bed for the Terlyn treatment was Georgetown Loop. Rocky Mountain spring water has lower saturation of oxygen due to the elevation and lack of oxygen even for breathing. Plus there is high probability that any particular gallon of Silver Plume water was virgin snow within the last week, with little exposure to air. Has no one pondered the extraordinary boiler longevity of the Rio Grande narrow gauge locomotives? What fountain of youth well do those locomotives drink from ?

Oxygen saturation of water has nothing to do with these boilers supposed longevity. That is looking in the wrong direction. The saturation of oxygen in air at 10,000 feet is identical to the saturation at sea level. Temperature has everything to do with it. Since the water was virgin snow last week, it would be closer to 32 F than summer water in the Corn Belt, ( 56 F ). The real Fountain of Youth for these mountain engines is the Low Relative Humidity during storage. Humidity saturating the scale deposits laying in intimate contact with boiler metal and in crevices is what degrades boilers during layup. Low humidity -> low rusting.

Most of the "magnetite coatings stop corrosion" blanket statement legend has been perpetuated by Terlyn in their LBS ( sic ) literature.

I have seen no other chemical company literature make this claim and Terlyn provides no second party substantiation.

Au Contraire, Mon Capitaine ! See this:

http://www.eutechinst.com/techtips/tech-tips45.htm
http://www.angelfire.com/mt/chemicalcleaning/magnetite.html

The water treatment cartels know fully well, the benefits of magnetite film protection of mild steel. They just don't pass it along through their marketing and sales people. As I stated a few days ago on RYPN from personal experience, they don't care a whit about solving customers' problems or protecting the customers' equipment. Most water treatment salesmen have absolutely no training in 100% makeup, air saturated boilers, a.k.a. locomotives.
As my prospective boss stated, " You'll never make it in this business, you want to solve people's problems. That is not our job. Our job is to sell chemicals. "

J.D, the short answer is minerals and oxygen are two different completely independent entities. Both have to be treated separately. There is no one chemical snake oil that does it all.

Agreed, Terlyn LSB is truly revolutionary. Depending upon raw water conditions, sofening may be beneficial and cost effective. If incoming TDS or Chlorides are too high, full or partial Reverse Osmosis may be a good idea. Many current users of Terlyn LSB, especially after their boiler is clean, need so little of the Terlyn, that they supplement with a little bit of Phosphate. What was omitted 10 to 15 years ago in the initial offering was that we must not let boilers stand cold and unprotected. I maintain that Sulfite is ineffective and causes multiple problems and solves none. Nitrogen blanketing, applied as the boiler is cooling down and before it draws air in, is the only effective wet layup means.

Regards,
Jim Conte
Lifetime student of steam, unabashed believer and proponent of Terlyn LSB