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What makes a steam boiler fail?

HeatingHelpHeatingHelp Posts: 231
edited June 2016 in THE MAIN WALL
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What makes a steam boiler fail?

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  • Jack GetkinJack Getkin Posts: 8Member
    What is considered an excessive amount of chlorides?
  • GreenGeneGreenGene Posts: 290Member
    One problem I saw seemed to be related to manufacturers making their castings too thin (saves money, increases profit the bean counter said) and we had certain brands develop horizontal cracks right across the back wall right at the water line 4"-6" long.

    I attributed it to the thin cast iron being exposed to the direct heat of the flame with no water behind it. The cracks would be right above the target wall at the top of the water line or just above it.
  • GreenGeneGreenGene Posts: 290Member
    Here's an interesting article related to marine boilers and the issues of salt and minerals.

    http://www.marineinsight.com/tech/boiler/understanding-boiler-feed-water-contamination/
  • GreenGeneGreenGene Posts: 290Member
    So this got me thinking and researching and got a lot of hits concerning the old steam ships.

    Seems some of them would use the seawater and they'd monitor the temperature, using two boilers to keep a head of steam up if one was going to a higher temperature they'd know the salt content was too high, I also read they'd draw water off and test boil it.

    Then they'd do something insane, they'd blow down the entire boiler into the sea, a violent action that would break off and discharge salt and mineral deposits, when the boiler went empty it would create a vacuum and refill itself with seawater.........no wonder they had so many disasters.
  • jumperjumper Posts: 1,221Member
    GreenGene said:

    So this got me thinking and researching and got a lot of hits concerning the old steam ships.

    Seems some of them would use the seawater and they'd monitor the temperature, using two boilers to keep a head of steam up if one was going to a higher temperature they'd know the salt content was too high, I also read they'd draw water off and test boil it.

    Then they'd do something insane, they'd blow down the entire boiler into the sea, a violent action that would break off and discharge salt and mineral deposits, when the boiler went empty it would create a vacuum and refill itself with seawater.........no wonder they had so many disasters.

    The good old olden days. When fuel was sufficiently inexpensive and the run short enough they could "evaporate" —we call it distill nowadays— boiler feed. The steam was not recycled because they used a jet condenser. One advantage was that there was no worry about lube getting into boiler.

  • Jamie HallJamie Hall Posts: 8,973Member
    To the extent possible, all modern steam ships (including the nukes) recycle the feedwater, using seawater cooled condensers. This has two advantages: you don't have to make as much fresh water for makeup (or the crew, and trust me -- evaporator water may be fresh, but it sure didn't taste good (ask me how I know!)) but also the seawater allows the condensers to pull quite a good vacuum, which improves the efficiency of the turbines. Sufficiently so that one can get considerably more power out of one's ship in cold water (such as the North Atlantic) than in warm water (such as the South Pacific). Sufficient to make several useful additional knots in cold water...

    Jet condensers became obsolete rather early on; almost all later ones are counterflow tube types, although there were some efforts at sheet designs.

    That said, the feedwater is treated rather heavily to avoid corrosion and scaling, and one does have to blow down the boilers now and then to reduce dissolved solids.
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • LarryKLarryK Posts: 44Member
    I got a kit for testing for clorides a few years ago. We were doing electrolytic etching of some steel plates in a salt water electrolyte. it requires diluting the water with a molar flask and then a titration but if you have any experience of chemistry it isn't that hard to do and the kit includes all the stuff. I think I got it from Graingers.
  • jumperjumper Posts: 1,221Member
    JamieHall is absolutely correct but the good old olden days provided somebody with the privilege of regularly going into the evaporator to crack off crud.
  • Started at twelve years old. Family heating oil company. Dad was the heat tech. Submariner vet. Electrician, pipe fitter, troubleshooter, tin-knocker, steam boilers, water boilers, warm air. Combustion man. "Learn what I show ya. You'll always have work. ""We're not plumbers. We'really heating men." Low pressure steam. Residential, commercial,Industrial. That was one of his fortes. Hence mine. Worked for the Bell system in the same capacity for fifteen years. He taught me to "gentle" that steam up there. Low pressure means low pressure. Adjust your BTU input. Never over fire. Undo abuse on the system. Have found overfiring to be one of the most common mistakes in our industry. "Oversize" pipework, ductwork. Always better than too small. Size your units properly. The lessons from that old sailor have served me very well these 47 years on the job. And his humility. "No worries kid. Anybody can make a mistake once and a while. If you never make a mistake, you ain't doing much."
  • NormanCNormanC Posts: 12Member
    If chlorides are a problem why not install a tap where you can manually add distilled water? Given that well-behaving steam system use very little water why pipe water to it to only add a few gallon per year? Seems to me a ball valve, a funnel, and a few jugs of distilled water would save a lot of boilers.
  • DanHolohanDanHolohan Posts: 14,298Member, Moderator, Administrator
    Usually because no one is aware of the chlorides.
    Retired and loving it.
  • I am not at all trying to say that it's not the chlorides as Burnham claims. But,

    Let's play devils advocate:

    Say you're a manufacturer that put out a whole lot of bad castings. Castings that had been out in the field for many years before it was even realized that there was a problem. Suddenly, boiler blocks begin dropping like flies. This could well represent an existential threat to the company.

    In such a scenario, the chlorides theory would seem tailor-made to quell the controversy.

    Just seems there is a lack of official back-up evidence or research, or other sources besides Burnham, on this most important issue.

    Or?



    New England SteamWorks
    Service, Installation, & Restoration of Steam Heating Systems
    newenglandsteamworks.com
  • DanHolohanDanHolohan Posts: 14,298Member, Moderator, Administrator
    It's real. They spent a ton of money on that research to figure out what was going on. I watched it happen at the time.
    Retired and loving it.
  • JackmartinJackmartin Posts: 125Member
    That is a very interesting observation. We get all our water from a pristine lake called Shoal lake and we are fortunate to regularly be voted as some of the best water in Canada. I remember a trip we made to Florida and how lousey the water tasted. I got into a conversation with a Florida native, I remarked on the water taste. He just sighed and told me when he was a lad the water was great, but ----- in his words, when they covered everything with asphalte the water turned bad. I latter found out he was right, the ground water was being depleted and as the soil in Florida is very porous the rain was not going back into the ground water because all the pavement was letting it run off. Nature hates imbalance ,so sea water was being drawn into the ground water space. I can only imagine the problems they would have if heating was a concern.
    All the best Jack

  • hot rod_7hot rod_7 Posts: 9,044Member
    edited October 4
    Chloride levels are increasing in many of our lakes and rivers and even deep wells. One of the main reasons in the snowbelt areas is related to the de and anti ice chemical being used on our roadways. Calcium chloride, mag chloride and other blends.

    Something like 40 tons per lane mile gets spread on I-70 across Colorado every time it snows.

    Chlorides in liquid form go on the roads ahead of incoming storms, anti icers. DOTs like using the liquid based chlorides Mag chloride, Calcium chloride as it handles and spreads easier, and helps the rock salt, sodium chloride work better.

    I travel with water test equipment when I do trainings now. Very rare to find tap water anywhere in the US that meets the boiler manufacturers spec, hardness, TDS, etc.

    Same applies to stainless indirect tanks, they have a tight chloride spec that is hard too meet with a lot of tap water.

    Thinner metals, higher chloride levels, it all spells trouble for water based systems.

    At the vary least invest in some water test meters and start checking. Know also water changes a lot from season to season, even from town to town.

    Water from lakes and surface sources tends to be higher in minerals and containments due to the exposure area.


    https://www.caryinstitute.org/newsroom/cutting-down-salt
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • izhadanoizhadano Posts: 75Member
    just adding my 2 cents ...
    Running new Pearless steam boiler since 2014 with original (~1920th) single pipe steam heating system modified into vacuum heating system. no steam traps, - more info in Dan's article - https://www.pmmag.com/articles/97633-a-new-look-at-vacuum-heating
    Adding water ~1 gal once in a winter season. I believe that bromide added is negligible. Other benefits includes higher efficiency, better comfort and control, less corrosion. etc.
  • gerry gillgerry gill Posts: 2,872Member
    izhadano said:

    just adding my 2 cents ...
    Running new Pearless steam boiler since 2014 with original (~1920th) single pipe steam heating system modified into vacuum heating system. no steam traps, - more info in Dan's article - https://www.pmmag.com/articles/97633-a-new-look-at-vacuum-heating
    Adding water ~1 gal once in a winter season. I believe that bromide added is negligible. Other benefits includes higher efficiency, better comfort and control, less corrosion. etc.

    wow. 1 gallon a season is incredibly tight system. Thats great.
    gwgillplumbingandheating.com

    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • DanHolohanDanHolohan Posts: 14,298Member, Moderator, Administrator
    That’s Igor. ;-)
    Retired and loving it.
  • GilmorrieGilmorrie Posts: 86Member
    Chloride concentration in carbon steel piping probably isn't too critical. It's a no-no for stainless steel. The Navy to preferred nickel-based alloys for piping high-chloride water. The Navy could afford that - it was peanuts in the overall cost of a new ship. But for residential hydronic or steam systems, Monel or Inconel would be too costly.
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