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Alternative fuels

  1. Oct 11, 2006 #1
    Why can we not use normal alcohols such as ethanol or methanol for the purpose of running our vehicles?
    is there any particular problem?
     
  2. jcsd
  3. Oct 11, 2006 #2

    russ_watters

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    Cost and availability.
     
  4. Oct 11, 2006 #3
    what do you mean by cost and availibility.
    its cheaper to produce alcohol from sugar and other waste products. methanol is hell cheaper than oil
     
  5. Oct 11, 2006 #4

    Danger

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    I don't know about ethanol, but there's no physical reason not to use methanol. Lots of vehicles run on it already, including high-power racers, and even 25 years ago Mohawk gasoline was blended with it. I had to use that in my Roadrunner to boost the octane level. There would be engine tuning modifications needed for the pure stuff.
    One potential problem is a safety issue. Alcohol burns with invisible flames, so passengers and rescue workers wouldn't know if there was a vehicle fire in the event of a crash or a fuel spill at a filling station. Maybe an additive would cure that.
     
    Last edited: Oct 11, 2006
  6. Oct 11, 2006 #5

    Mech_Engineer

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    Of course the first big reason is infrastructure. We just don't have the capability to make enough alcohol for everyone right now.

    The next big reason is the chemical energy stored in them. Because gasoline has excellent energy density (as does diesel), vehicles running off of alcohols will get worse gas mileage. biodiesel's energy content is also lower than petro-diesel, which accounts for why diesels trucks running off of biodiesel get worse mileage; however, the drop is less significant than gasoline to ethanol, and biodiesel has a much higher content than alcohol. Hydrogen is an even worse option in terms of combustion, because it only contains about 12 kilojoules per liter at STP, far less than any of the other options.

    Gasoline- 34.2 MJ/L
    Diesel- 38.60 MJ/L

    BioDiesel- 32.97 MJ/L

    Hydrogen- 12 kJ/L

    Methanol- 15.912 MJ/L
    Ethanol- 21.1 MJ/L


    here is an interesting presentation in PDF form that compares several different alternative fuel sources:
    Sandia National Labs Presentation
     
    Last edited: Oct 11, 2006
  7. Oct 11, 2006 #6

    LURCH

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    One of my profs at colledge (fuel and enrgy are not his field) recently pointed out that if we converted every inch of unused ground here in the US to the growth of corn, and used all that corn just to make alchahaul, we could produce enough to supply approximately 1/10 of our consumption.

    Rather daunting, but this fellow may not be completely reliable for information on this topic (I think he may b a bit of a conspiracy theorist).
     
  8. Oct 11, 2006 #7

    brewnog

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    Maybe not exactly the right numbers Lurch, but the fact that we don't have nearly enough arable land to develop an alcohol economy based upon traditional methods are well documented, i.e. it's a valid point.
     
  9. Oct 11, 2006 #8
    I too accept that all the world's fuel needs cannot be run on alcohol as there is not enough land space. However, it is not entirely impossible to create one. Would it be cheaper to run?
    Milage apart, it would also have a lower price than the present price of petrol. In the race for hybrid cars, why is this option not being utilised?
     
  10. Oct 12, 2006 #9

    Mech_Engineer

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    Alcohol cars are not being pursued as agressively as other options for the exact reasons above, i.e. we already told you. The possibility of it being cheaper is useless, because we wouldn't be able to make enough alcohol in the first place.
     
  11. Oct 12, 2006 #10

    Clausius2

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    Here in CA alcohol cars would receive tickets for driving drunk.
     
  12. Oct 12, 2006 #11

    Danger

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    :rofl: :rofl:
     
  13. Oct 13, 2006 #12

    brewnog

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    Banerjeerupak, conventional fuels are not inherently expensive. Taxation and politics have more to do with the price of petrol than well to wheels production costs.
     
  14. Oct 13, 2006 #13

    Danger

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    So that's why my 100 mpg carbeurator never got...
    Never mind... :grumpy:
     
  15. Oct 14, 2006 #14
    got your point... but do tell me about the milage that such a fuel would be able to give in a normal engine. thats the reason i got onto this
     
  16. Oct 14, 2006 #15

    Astronuc

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    Refer to this, particularly page 2

    http://www.eere.energy.gov/afdc/pdfs/fueltable.pdf

    Comparison of gasoline, diesel, methanol, ethanol and other fuels.

    Methyl Tert Butyl Ether would be great energywise, but it is carcinogenic and has contaminated water supplies in areas where it is used as a gasoline additive.

    Methonal is toxic and fatal if a sufficient amount is ingested.
     
  17. Dec 28, 2006 #16

    sas3

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  18. Feb 16, 2007 #17
  19. Feb 16, 2007 #18

    sas3

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    I forgot all about this post.

    Thanks for the linK Darren.
     
  20. Feb 22, 2007 #19
    Hydrogen

    The future is and should be hydrogen from renewable sources. If u take a small part of the american desert (small by comparison) and build electrical/thermal power plants u would be able to generate enough electricity for homes and enough electricity to produce hydrogen at a value not so much more expensive than oil. If you use all the american desert i think u can cover the whole world. I wrote my senior year book in mechanical engineering about this subject, and did an all out engineering and cost research. The infrastructure is present for hydrogen, because all u need to do is modify existing fuel stations. so its not about the price or infrastructure, its about actually doing it.
     
  21. May 21, 2008 #20

    Astronuc

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    Synthetic fuels research picked up during the 70's and 80's during the previous fuel crisis. The research level rises and falls with the price and supply of oil and alternatives.
     
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