Notices
Results 1 to 29 of 29

Thread: Maximum temperature in a wood fire

  1. #1 Maximum temperature in a wood fire 
    Forum Professor
    Join Date
    Sep 2007
    Posts
    1,079
    What is the approximate maximum temperature achievable in a wood fire, please? No bellows or other devices, simply burning wood in a fireplace.


    Reply With Quote  
     

  2.  
     

  3. #2  
    Reptile Dysfunction drowsy turtle's Avatar
    Join Date
    Mar 2009
    Location
    UK
    Posts
    2,256
    I'm sure it's possible to achieve upwards of 900K. But it very much depends on the type of wood, and type of fireplace.


    "The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair." ~ Douglas Adams
    Reply With Quote  
     

  4. #3  
    Suspended
    Join Date
    Jul 2009
    Posts
    323
    What kind of mischief are you planning on getting up to? I might want to try it, too....
    Reply With Quote  
     

  5. #4  
    Forum Professor
    Join Date
    Sep 2007
    Posts
    1,079
    Smelting.......

    Why is the curie point of iron less than the melting point?
    Reply With Quote  
     

  6. #5  
    Forum Isotope Bunbury's Avatar
    Join Date
    Sep 2007
    Location
    Colorado
    Posts
    2,590
    I don't know. However I do think you need a more controlled fire than an open fireplace because you will draw a lot of excess air which, being mostly nitrogen, absorbs a lot of heat and cools the flame. I think you'd get a hotter fire with charcoal and some way to control the airflow.

    Smelting iron - really? This needs a reducing agent so all the more reason to use charcoal and restrict the air flow.

    Good luck.
    Reply With Quote  
     

  7. #6  
    Forum Professor
    Join Date
    May 2005
    Posts
    1,893
    Quote Originally Posted by free radical
    Why is the curie point of iron less than the melting point?
    Because it takes less energy to break the magnetic alignments between atoms than it does to break their chemical bonds. There is simply less energy stored in the magnetic alignment. Of course in a way that's just restating that the curie point is less than the melting point, but that's the best explanation I can give.
    Reply With Quote  
     

  8. #7  
    Suspended
    Join Date
    Jul 2009
    Posts
    323
    Well you can cook smelts in a frying pan.


    Whatcha gonna make with your iron? Iron age weapons?!? Count me in!
    Reply With Quote  
     

  9. #8  
    Forum Professor
    Join Date
    Sep 2007
    Posts
    1,079
    Cheers

    We've not decided what to make, as yet. I'm partial to making a magnet (fabulous demonstration of physical principles for the young radicals that tend to run around here) tho wee weapons (there's only a small amount of iron to work with) are also on the short list.
    Reply With Quote  
     

  10. #9  
    Reptile Dysfunction drowsy turtle's Avatar
    Join Date
    Mar 2009
    Location
    UK
    Posts
    2,256
    For smelting, eh? I have some advice for increasing the heat then:

    -try to keep the fire enclosed within an insulating container, like brick or ceramic, but leave plenty of air holes.

    -You'll want something that will burn for a long time, so try coal. Or, if you're trying to do this without buying materials, make your own charcoal first by heating it slowly over a fire, below its ignition point. Coal/charcoal won't burn hoter, but they will burn for longer, so if enough heat is retained the temperature should reach over 1000K.

    -For a quick burst of heat, try sawdust of shredded paper; the large surface area means it burns hot, but quickly.
    "The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair." ~ Douglas Adams
    Reply With Quote  
     

  11. #10  
    Suspended
    Join Date
    Jul 2009
    Posts
    323
    You can make a short Gladius with a smaller amount of iron!
    You just need an anvil, a bucket 'o' water and a hammer...
    Reply With Quote  
     

  12. #11  
    Forum Freshman
    Join Date
    Jul 2009
    Posts
    21
    I hate to do this cause it feels like I'm hijacking a topic, but I do feel the question's at least fairly relevant.

    How is it possible to reach such mind-bendingly high temperatures like they do in many industries? I mean, I've seen oxyhydrogen torches, but I don't think I've seen anything hotter than that.
    Reply With Quote  
     

  13. #12  
    Forum Professor marcusclayman's Avatar
    Join Date
    Mar 2009
    Posts
    1,704
    e=mc2
    Dick, be Frank.

    Ambiguity Kills.
    Reply With Quote  
     

  14. #13  
    Forum Freshman
    Join Date
    Jul 2009
    Posts
    21
    Quote Originally Posted by marcusclayman
    e=mc2
    I take it you mean a flame can be made hotter by increasing the amount of products being burned at any given time? Does that simply mean that increased surface area (such as the paper sawdust drowsy turtle suggested) will result in a hotter flame? I would think there's a limit to how hot you can make a flame simply by increasing surface area though.
    Reply With Quote  
     

  15. #14  
    Forum Ph.D.
    Join Date
    Jan 2009
    Posts
    940
    Flame temperature is limited by WHAT is being burned not how MUCH. the bond energy and heat of combuston are the prime factors
    air - wood as shown is not very hot relatively speaking. Not hot enough to smelt iron by the way.
    wood-oxygen would be much hotter.
    oxy-hydrogen comes in at 2800C 5072F
    there some exotic combinations even hotter. dicyanoacetylene for instance.
    If C4N2 is burnt with O2, the resulting flame will have a temperature of 5260 K (4987 C, 9008 F). However, if 5260 K (4987 C, 9008 F). However, if C4N2 is burnt with O3, then the resulting flame will have a temperature of 5516 K (5242.85 C, 9469.13 F).
    Burning a lager quantity gives you more total heat but no increase in temp.
    Reply With Quote  
     

  16. #15  
    Forum Professor marcusclayman's Avatar
    Join Date
    Mar 2009
    Posts
    1,704
    Not all fires are created equally.

    This is a subjective experience of mine, but I'm sure others know what I'm talking about.

    Some people suck at starting fires, even though the matterials are the same. Some have to use gasoline and/or paper products, while others just use twigs, leaves, bark, etc...

    You can create fires in different shapes by stacking the wood in different ways. For example making a "tower" of 4 sticks(one end of each stuck into the ground, sticking straight up, they must be same height, as well as close enough and sturdy enough to stick a pan on,) then filling the area between the sticks with smaller sticks grass and leaves. This allows for a very fast burning very hot fire that is ideal for cooking quickly in the wilderness. Because it's shaped like a "tower" and not a pile of wood, there is more oxygen per fuel. Since it burns so hot, very little coal is made, and so the fire doesn't last like a regular camp fire would.

    Burning a fire in a barrel with an fire next to it(not in a barrel) using equivelent fuel sources will show you that how something burns determines more about the heat it produces than how much you are burning. Ultimately the difference lies in a scale from "hot, fast and efficient" to "cool, slow and inefficient" ultimtely you want a fuel that burns exactly how hot you need it to, as efficient as possible(or your wasting your time and energy lugging/buying wasted fuel) while trying to find something that burns for long on little fuel. Wood burns for a long time, but not especially hot, and not at all efficiently.

    If your going to be smelting, it's probably most efficient to use some sort of gas as fuel and making some sort of blast furnace. Coal is not necessarily expensive, but considering delivery or transportation effort/costs, plus the amount of work you need to put into moving it around, the mess it makes, the health problems and pollution... there are just many reasons to opt for something else... the only cool thing about coal, though, is that you can make it yourself, cook on it, and in some places, it's very very cheep if you opt to buy it.
    Dick, be Frank.

    Ambiguity Kills.
    Reply With Quote  
     

  17. #16  
    Forum Ph.D.
    Join Date
    Jan 2009
    Posts
    940
    Don't really care how you stack it the max temp will be the same.
    Bottom line is you are not going to smelt iron in a fireplace wood fire
    It will require charcoal and forced air at a minimum.
    The end!
    Reply With Quote  
     

  18. #17  
    Forum Professor marcusclayman's Avatar
    Join Date
    Mar 2009
    Posts
    1,704
    It does matter how you stack it.

    The max temp is the max temp, but you won't get as close to the max temp unless you stack it a certain way.

    Go ahead and do an experiment, start 3 small fires. One that is just a layer of wood on the ground. One that's a classic tepee stack of wood, and one that's built like a tower. The one on the ground will burn slower and less hot, and the one like a tower will burn faster and more hot. The other one will be in between.
    Dick, be Frank.

    Ambiguity Kills.
    Reply With Quote  
     

  19. #18  
    Forum Ph.D.
    Join Date
    Jan 2009
    Posts
    940
    Ain't going to happen without charcoal and forced air, go wiki "smelting iron"
    you can only lead a horse to water.
    Reply With Quote  
     

  20. #19  
    Forum Professor
    Join Date
    Sep 2007
    Posts
    1,079
    Mmm, any odds on whether a butane torch would do the job?
    Reply With Quote  
     

  21. #20  
    Forum Professor
    Join Date
    May 2005
    Posts
    1,893
    Quote Originally Posted by Shadow
    I hate to do this cause it feels like I'm hijacking a topic, but I do feel the question's at least fairly relevant.

    How is it possible to reach such mind-bendingly high temperatures like they do in many industries? I mean, I've seen oxyhydrogen torches, but I don't think I've seen anything hotter than that.
    Usually to reach really high temperatures in industry they don't "burn" fuel to create flames, instead they use either arc furnaces or induction furnaces. You can also make ordinary flames really, really hot buy using powerful radio or microwave emitters to dump energy into them.
    Reply With Quote  
     

  22. #21  
    Forum Freshman
    Join Date
    Jul 2009
    Posts
    21
    Quote Originally Posted by Scifor Refugee
    Quote Originally Posted by Shadow
    I hate to do this cause it feels like I'm hijacking a topic, but I do feel the question's at least fairly relevant.

    How is it possible to reach such mind-bendingly high temperatures like they do in many industries? I mean, I've seen oxyhydrogen torches, but I don't think I've seen anything hotter than that.
    Usually to reach really high temperatures in industry they don't "burn" fuel to create flames, instead they use either arc furnaces or induction furnaces. You can also make ordinary flames really, really hot buy using powerful radio or microwave emitters to dump energy into them.
    Oh, okay, I didn't even consider the possibility that they used electricity as their heat source instead of combustion.
    Reply With Quote  
     

  23. #22  
    Forum Freshman
    Join Date
    Jun 2011
    Posts
    5
    Quote Originally Posted by marcusclayman
    It does matter how you stack it.

    The max temp is the max temp, but you won't get as close to the max temp unless you stack it a certain way.

    Go ahead and do an experiment, start 3 small fires. One that is just a layer of wood on the ground. One that's a classic tepee stack of wood, and one that's built like a tower. The one on the ground will burn slower and less hot, and the one like a tower will burn faster and more hot. The other one will be in between.
    I know for a fact that stacking the wood differently does exactly what you stated, but he might have meant that its irrelevant in the sense that top-temp is still insufficient (?).

    Im might also be off here, but as far as I know, the temp is enough to make oxides (800-1000c), such as CaO, or better yet KO. The OP might want/need atwo-stage solution, first turning an inexpensive material to an oxide, then used the product to boost the fire to sufficient temp.
    ,,, Though I must admit that im only familiar with "first step" in making the oxides, but using them pyrotechnically is mere idea i dragged out of my A-hole.
    Reply With Quote  
     

  24. #23  
    Geo
    Geo is offline
    Forum Junior
    Join Date
    Nov 2009
    Location
    New Zealand
    Posts
    273
    Temperature means a phase change. It won't get hotter!

    When a phase change occurs temp stays constant!
    Reply With Quote  
     

  25. #24  
    Forum Ph.D.
    Join Date
    Jan 2009
    Posts
    940
    your a-hole is mistaken, oxides are already oxidized and cannot cotribute any more energy to a fire
    Reply With Quote  
     

  26. #25  
    Forum Freshman
    Join Date
    Jun 2011
    Posts
    5
    Thanks for wiping my A-hole

    Edit:
    I found this,
    http://en.wikipedia.org/wiki/Fire#Ty...res_and_flames

    A candle reaches 1000c, and a cigarette (while drawing), up to 700c. I imagine that a fiery bonfire is higher temps, but im likely decieved since bonfires might merely have more flames.

    How about a simple kiln? Would insulating a tower of wood inside, example, an empty oil barrel, with an air intake under the fire (Im guessing a simple grill to hold the wood above the air intake), and of course an exhaust at the top of the barrel,,, Would simple methods of this calibre be enough to make a stronger/hotter fire from firewood then whats usually its limits?
    Reply With Quote  
     

  27. #26  
    Forum Ph.D.
    Join Date
    Jan 2009
    Posts
    940
    your kiln caper could possibly work if you used a forced air blower augmented with some oxygen from a cylinder. use fire brick though. sounds like a lot of work to get a piece of iron. What are you smelting anyway? if its iron oxide you will have to reduce it with carbon.
    Reply With Quote  
     

  28. #27  
    Forum Freshman
    Join Date
    Jun 2011
    Posts
    17
    I was researching how hot a methane flame from your stove actually get.

    My research indicated that the answer was 900 C but, in the event of a turbulent flame, the answer is 1250 C!

    Note, with extreme caution, by hitting slightly those metal metal caps on your stove (I did this accidentally once), you may get a much louder gas rushing noise and a turbulent CH4 burning stream which, apparently, may be 350 C hotter!

    So by turning your fire into a blast furnace (that is, adding a strong air current), it will get hotter.
    Reply With Quote  
     

  29. #28  
    Forum Ph.D.
    Join Date
    Jan 2009
    Posts
    940
    forget it you are not going to melt steel in your fire place or stove- good luck and good bye - this one is worn out.
    Reply With Quote  
     

  30. #29  
    New Member
    Join Date
    Jan 2013
    Posts
    1
    575 oF to 1100 oF (300 - 600 oC ) the main energy in the wood is released when fuel vapors containing 40% to 60% of the energy burn
    Reply With Quote  
     

Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •