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  1. #1
    Graeme Sharp is offline Aluminum
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    I have read in the past a number of accounts of fire breaking out due to spontaneous combustion of the coal in the bunkers of coal fired steam ships. With the renewed interest in possible coal fired ships due to the high oil prices, I would be interested to learn what is the latest method of preventing bunker fires. I would also be interested to learn from any marine engineer what precautions were taken to prevent bunker fires when coal fired ships were more numerous.

  2. #2
    Geoffm is online now Aluminum
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    The most excellent "Ignition Handbook" by Vyto Babrauskas (Publ SFPE, 2003) is an excellent source on ignition. Weighs about 10kg... It has a few pages on spontaineous ignition of coal, the causes and history, etc. let me know if you wnat me to copy those pages.
    It reports a Royal Commission report in 1876, where the prinicple factors identified were the coal lump size (powder is more prone to self heating), wet or dry, and time. Ship coal fires had a median time of 60 days from leaving port to the fire.
    It goes on to say that the self heating is caused by oxidation of the coal, with the coal and combustion going through several stages prior to flaming ignition.
    The NFPA handbooks should also have something on it, but not the same detail. My copies are buried in the bookshelf but I can get them later if you want.
    Geoff
    (Fire engineer)

  3. #3
    plannerpower is offline Hot Rolled
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    An interesting subject. Here is some information;

    http://www.lafire.com/fire_boats/art...lShipFires.htm

    It seems that there was a bunker fire on the Titanic;

    http://www.worldwideschool.org/libra...nic/chap3.html

    There is speculation that the fire may, at least indirectly, have contributed to the sinking;

    http://www.titanic.com/modules/artic...icle.php?id=27

  4. #4
    Graeme Sharp is offline Aluminum
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    Geoff in NZ,
    Thank you for the ofer of information on bunker fires. I would be grateful for any data that you may have as I may be involved with a coal fired ship at some time in the future, though I can't say much about it at present.
    I can receive any information that you have via e-mail or via the Forum. Thanks for your assistance.

  5. #5
    Geoffm is online now Aluminum
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    Graeme - You have mail I will have a look through the NFPA handbook later once I clear the boxes out of the way, to see if there is anything useful. I have found Vyto Babrauskas to be very helpful if you have anything specific you want to knwo that is not covered in his book. Have a look at www.doctorfire.com.
    Geoff

  6. #6
    JST's Avatar
    JST
    JST is offline Diamond
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    I have seen that power plants (specifically High Bridge plant in St Paul) kept coal in "piles" that were 20 ft or so tall, as large as a small city block, and very flat on top.

    They would work over that coal, with heavy loaders compacting it regularly. I think they also turned over piles from time to time.

    Of course that coal was exposed to rain, etc, so the water-related reaction was more likely.

    I noted that flattening and compacting were called out in the article also.

  7. #7
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    TechnicalTom is offline Aluminum
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    If I remember correctly, the explosion and sinking of the Maine in Havana harbor has been attributed to a coal bunker fire. Said bunker was next to a powder magazine. (D'oh!) This started a war with the Spanish and upped circulation of Hearst newspapers. Anybody remember seeing the TV documentary on this?

  8. #8
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    rvannatta is offline Hot Rolled
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    It's my impression the bunker fires were managed by sealing the bunker and turning on the steam to create an Oxy-starved environment.

  9. #9
    Jeff_G is offline Hot Rolled
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    Joseph Conrad's story "Youth" gives an account of a coal (cargo) fire on a British brig. It's a good read if you can find it.

  10. #10
    JST's Avatar
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    JST is offline Diamond
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    It's my impression the bunker fires were managed by sealing the bunker and turning on the steam to create an Oxy-starved environment.
    Isn't that just about exactly the same system as in a coal gasifier...... ? Get the coal burning, and shoot in steam.

    One link did mention that with water, the coal fire would make its own oxygen, too. I am a little suspicious of that, on an energy balance basis, but I may not have considered everything.

    For sure, the fire may be better than making a hold or bunker full of potentially explosive hydrogen and CO mix.

  11. #11
    imported_brian_m is offline Aluminum
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    Slightly OT but interesting. This story comes from my Father-in-Law who was in the shipping business. Many years ago there was a coal gas production facility in this area. Some genius had the idea that the roasted coal residue, called "clinker" I believe, could be sold in Japan. A ship was loaded and sent across the Pacific. On arrival the clinker had to be removed by workers with jack-hammers. Apparently during the voyage the material had settled and welded itself into a solid mass.

    Considering the previous posts it would appear they were very lucky the material did not catch fire.

    Brian

  12. #12
    Forrest Addy is online now Diamond
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    In this day and age it seems to me that liguid N2 in cryogenic storage and bunker inerting on need will solve any fire (and voyage underwriting) hazards.

    Coal has never been a good fuel for IC engines so I gues that rules out large diesels now in service. Does that mean steam engines? Gassified coal pilot fuel engines? There's some opportunities here but bunkering with coal will still be an expensive business.

  13. #13
    Peter S is offline Diamond
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    Graeme,
    When/if you can, would be good to learn how a modern coal-fired ship would operate.

    Skinner back in business? I remember reading of great hopes at one stage of Unaflows going to Poland (1980's?), but I think it fizzled.

    Old Scotsmen being enticed out of retirement homes, dusty rolls of drawings being taken from archives.....

  14. #14
    Graeme Sharp is offline Aluminum
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    Peter,
    LOL. You have hit the nail on the head. This is one old Scotsman being enticed out of retirement, and trying to find my old books and remember stuff from ages ago. Can't say much about the project now but will in due course.

  15. #15
    Thermo1 is offline Senior Member
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    Graeme,

    Babcock and Wilcox (Steam, 40th edition, page 11-16) has this to say about bunker fires. This concerns mainly large coal burning power plants, but some of the advice may help.

    "An attempt should be made to smother the fire while quickly discharging the coal. Continuty and uniformity of the hot or burning coal discharg aggravates the danger. The bunker should be emptied completely; no fresh coal should be added until the bunker has cooled and the cause of the fire determined.

    The fire may be smothered by using steam or CO2. CO2 settles thrugh the coal and displaces oxygen from the fire zone because it is heavier than air. Permanant piping connections to the bottom of teh bunker may be made to supply CO2 on demand. The CO2 should fill the bunker, displace the air, and smother the fire.

    It is highly desirable to completely extinguish the fire before emptying the bunker. This is rarely possible because of boiler load demands and the difficulty of eliminating air flow to the fire. However, the use of steam or CO2 to smother the fire can minimize the danger.

    Bunker flow problems which result in dead zones may contribute to fires. Thermocouples installed in the bunker can monitor the temperature of the stored coal."

    Hope this helps.

    If the project goes through, keep us posted.

    Thermo1

  16. #16
    bronto48 is offline Hot Rolled
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    I used to work in a coal fired power plant. Bunker fires were an occasional nuisance. The best way we had to extinguish them was to run the bunker empty as soon as the fire was discovered because the burning coal would form clinkers and bridge or plug the feeder pipe below. Later, we re-designed the bunkers for better flow, eliminating dead areas, and used 300 series stainless liner panels for better feeding and less bridging of the coal. It would not stick to the bunker sides very much after that. Also, at periodic overhauls, we adopted the routine of always completely emptying the bunkers during the final hours before the unit was scheduled off. That avoided a mass of "stagnant" coal just sitting there for a month or more during the overhaul.

    Coal pile fires were dug out and extinguished with water.

  17. #17
    ttok is offline Cast Iron
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    I recall that coal piles at powerplants are first rolled to compact out most of the oxygen, then sprayed with diesel oil to "seal" out further air.

    In some crude carrying ships (VLCC's), an inert gas is kept over the cargo holds. This inert gas is taken from the oxygen-poor stack gas from the diesel engine exhaust. Some oxygen is present, but not enough to support combustion (below the LEL). Inert gas is necessary because many VLCC's ballast sea water into 25% of the cargo hold on the empty return trip so that the rudder and prop are under water! Crude oil vapors are present in the explosive range in the holds after the oil is unloaded, because air is drawn in when the oil level in the hold drops. (When the holds are full of oil, the vapors above the oil are above the UEL, and will not usually ignite.) These are expelled out the masts of the ship during the act of ballasting. Lightning or static electricity has caused several disasters when the ships were ballasting - the "spark arrestor" on the masts seldom work. Seems like this might work for coal piles in the hold too. A.T.

  18. #18
    rvannatta's Avatar
    rvannatta is offline Hot Rolled
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    speaking of bunker fires you might be interested to read the testimony of some fireman on the HMS Titantic. There is evidence that it had a very hot bunker fire in the hold right where it was ultimately holed by the iceberg. There is a suggestion disputed by others that the bulkhead that failed was fire weakened by a nagging bunker fire that had been burning since the ship left Southhampton.


    Hms Titantic bunker fire

  19. #19
    rvannatta's Avatar
    rvannatta is offline Hot Rolled
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    speaking of bunker fires you might be interested to read the testimony of some fireman on the HMS Titantic. There is evidence that it had a very hot bunker fire in the hold right where it was ultimately holed by the iceberg. There is a suggestion disputed by others that the bulkhead that failed was fire weakened by a nagging bunker fire that had been burning since the ship left Southhampton.


    Hms Titantic bunker fire

  20. #20
    Peter S is offline Diamond
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    What with the Titanic hull being weakened by cold water (theory #1 of 100) and heat (theory #2 of 100), its a wonder the sister ships didn't break up and fall apart, isn't it [img]smile.gif[/img]
    Man, I am sick of Titanic stories.
    And now most people think it was some kind of romantic tale, though a bit hard on the men of course.
    rvannatta, don't mind me, I just like to complain now and again!

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