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Wood fire in compressed air chamber?

  1. Jan 8, 2008 #1
    Hi.

    What happends when i put fire to wood that I have in a chamber
    with a pressure of about 15 kg/cm2 = 14.710 Bar = 213,3 Psi.

    Will it burn as usuall or much faster?

    Will I get a very high pressure?

    How High pressure can I get?

    Magi
     
  2. jcsd
  3. Jan 8, 2008 #2

    mgb_phys

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    Science Advisor
    Homework Helper

    It would burn faster than usual, assuming this is a normal atmosphere.
    Fire is a major danger in decompression chambers If you have an oxygen atmosphere things can burn very quickly, you have to be careful about even having spilled gas/diesel on your shoes.
     
  4. Jan 9, 2008 #3
    Wood burning needs circulation of air. I think in a pressurized chamber like that, the circulation is not easy to happen.
    You may check the key word gasifier.
     
  5. Jan 9, 2008 #4

    I can have a smal fan in the chamber that blow/circulate the air through the fire maybe.
    The gasifier I read about is for normal open non compressed systems and is no fun. :)

    I want a compression chamber were I can burn wood under start pressure of about
    15 kg/cm2 = 14.710 Bar = 213,3 Psi and then have the pressure go up to
    200 kg/cm2 = 196 Bar = 2844 Psi and have the inside of the tube isolated so the heat of the gas stay when I run the pressure through a air motor or turbine to make electricity and ordinary compressed air as a energy storage.

    Is that a effective way to get electricity?

    Is anybody making systems like this anywere in a smal scale for home users?

    Is it interesting?

    Magi
     
    Last edited: Jan 9, 2008
  6. Jan 9, 2008 #5
    I don't think at high pressure you will have higher efficiency because the burning reactions in general are making more gas molecules (H2O, CO) so the higher the pressure, the more the equilibrium shifts to the left.
    Some thing for home use at such a high pressure i have never heard.
     
  7. Jan 9, 2008 #6

    RonL

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    Gold Member

    Hi Magi
    A good question, but if there is point or two of value here, the issue of safety in a user friendly setting, is nonexistant in a device that is opened and closed by someone with little or no training.
    The key issue here is HIGH PRESSURE, and HEAT, which produce an EXTREME CAUTION zone.
     
  8. Jan 9, 2008 #7
    Every engine in a car produce high pressure and heat and when I was young I
    opend engines and repaired and trim them, so I am sure it is possible to produce a system that can be handled by ordinary people, so that they can have a safe power station at home running on solid fuel, simpel, safe and cheap for everyone.

    It is a matter of engineering to make it safe and fail proofe, isn't it.

    But the question is how high pressure can you get and how efficient can it get.

    Magi
     
  9. Jan 9, 2008 #8

    RonL

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    Gold Member

    A little research on high pressure steam boilers, might give some insight as to why this might not be a good "home use system".

    As i stated, the (heat/pressure/size) relationship is the point of great concerne.

    Ron
     
  10. Jan 9, 2008 #9

    rcgldr

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    Homework Helper

    The wood should burn much faster at higher pressure. What would be the point of this though? How would you quickly circulate the air at this high pressure. The system would require a high pressure, high air flow, pump for the air intake, and some type of pressure maintaining exhaust system. If the goal is just more heat, then just a fan to keep the air moving at a moderately fast flow will do the job, similar to a blast furnace.
     
  11. Jan 9, 2008 #10
    why don't you get a compressed air tank with those little air gun things and shoot air at the fire
    if done at the right place i think it makes a bigger fire
     
  12. Jan 9, 2008 #11

    russ_watters

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    Staff: Mentor

    As others stated, what you are thinking of trying is dangerous.

    Beyond that, it won't do anything useful. In order to generate power, the air/exhaust needs to move through the turbine. You can't have a constant high pressure in some vessel and still have the air moving through a turbine. You also can't just blow air into a vessel and have it spontaneously increase in pressure. Something has to act on the air to move it (like the fan you are talking about). But if you use a fan to move the air, the fan is what is producing the energy (and also using the energy).

    You really should look into how a steam engine works. What you are trying to do is similar, but missing some pieces.
     
  13. Jan 9, 2008 #12
    A car have the same pressure and heat as a steam boiler and if handled wrong can explode and kill.
    The thing is if it is possible to build a system with many smal chambers that you burn solid fuel in and is solid as todays engines, to be able to handle pressure safely.

    The tube have all the air and solid fuel it need to create a high pressure and heat,
    as in a normal engine but the fuel will burn much slower.
    In the tube there can be a fan that can circulate the air as it burn.
    The whole inside of the tube can be isolated so that the created exhaust gas heat can be contained in the gas while you let it out to a turbine after all the fuel have burned out.
    In a normal engine the gas is directly in contact with the walls and the heat that is tranferes through the wall is cooled away and is a energy loss.
    In this system you can isolate it and after the turbine taken the exhaust gas it can be loaded again if there are enough of other tubes that can be running while the temp of the tube is cooled and loaded up.

    This could be an idea to gasoline engines maybe.
    The whole gasoline engine could be isolated and more efficient if there were enough cylinders running while the cylinder cools down to a temp so the fuel dont self ignite when it later is loaded again when it is its turn.
    Its a compleately crazy idea because the engine would need to many cylinders but i like my insane brain and maybe someone can make something of it. :)
    But I guess the best idea to get a normal engine more efficient is to use a system called turbosteamer from BMW.

    You are a funny man. :)

    I take a tube and put a solid fuel in it like wood and then i fill the tube with compressed air so that the wood have enough air to burn compleately.
    When it burn it will increase in pressure just as in a engine before the piston start move down, but slower. Then I let the exhaus gas out to a turbine and it will run and the pressure will go down in the tank until the pressure in the tube is at atmospheric level.
    The system have all its solid fuel and compressed air it needs before it is ignited.
    I do not plan to fill it with more air when it burn.
    The fan I put in the tube can be running on electricity by wires through the tube wall but it need to run in a very high pressure and heat.
    I am not sure you understand what I am trying to explain here.


    Master of Science in Engineering Physics

    Magnus Ivarsson
     
    Last edited: Jan 9, 2008
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