cyclonic
Posts: 182
Joined: Mon Jan 10, 2005 1:18 am

Biofuels In Aviation - A Possible Alternative?

Tue Jan 10, 2006 1:30 am

Hi all,

I think some of you would've heard of biofuels such as Ethanol.
With biofuels becoming an alternative to petroleum and promising more performance, is there a possibility that such fuels could be adapted for use in the aviation industry, especially for jet flight?

With fuel costs being a driving factor, correctly engineered biofuels could bring enormous cost savings and be enviromentally friendly.

Anyone have any thoughts on this?
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mrocktor
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RE: Biofuels In Aviation - A Possible Alternative?

Tue Jan 10, 2006 2:44 am

While it is certainly possible to run jet engines off bio fuels (such as ethanol) they carry severe penalties. Compared to jet-A, all bio-fuels (and hydrogen as well) have either poor energy/mass or poor energy/volume ratios (or both).

A poor energy/mass ratio means that you need a lot more fuel to carry the fuel. Heavier fuel means more fuel is needed for the same route, and the progression is not linear, it's exponential.

A poor energy/volume ratio means that the fuel needed to complete a route just wont fit in existing aircraft. New aircraft would have to be designed with increased tankage - which would mean heavier aircraft, more fuel needed and enter the cycle described above.

All in all, aviation is one place where "enviromentally friendly" fuels actually are not. It would be much better to convert all automobiles to ethanol than to try to mess with planes.

mrocktor
 
wingscrubber
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RE: Biofuels In Aviation - A Possible Alternative?

Tue Jan 10, 2006 3:26 am

Present school of thought is that Cryoplanes will replace kerosene burning jet aircraft, using liquid hydrogen or more likely liquid natural gas.
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cyclonic
Posts: 182
Joined: Mon Jan 10, 2005 1:18 am

RE: Biofuels In Aviation - A Possible Alternative?

Wed Jan 11, 2006 12:44 am

Hi guys,

Thanks for the heads up. Very cool feedback!
Keith Richards: The man that Death forgot...
 
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HAWK21M
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RE: Biofuels In Aviation - A Possible Alternative?

Wed Jan 11, 2006 1:09 am

Quoting Wingscrubber (Reply 2):
Cryoplanes will replace kerosene burning jet aircraft

Any good links available on the same.
regds
MEL
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Oryx
Posts: 123
Joined: Fri Nov 18, 2005 9:25 pm

RE: Biofuels In Aviation - A Possible Alternative?

Wed Jan 11, 2006 2:39 am

Quoting Wingscrubber (Reply 2):
Present school of thought is that Cryoplanes will replace kerosene burning jet aircraft, using liquid hydrogen or more likely liquid natural gas.

Why? If you can make hydrogen, you can also produce hydrocarbons (i.e. kerosene) which are a lot easier to handle. If you take the carbon from crops it's even C0_2 neutral. Only disadvantage is you can't eliminate nitro-oxides from a kerosene flame like you could from a hydrogen flame.
 
Pyrex
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RE: Biofuels In Aviation - A Possible Alternative?

Wed Jan 11, 2006 2:43 am

Quoting Oryx (Reply 5):
Only disadvantage is you can't eliminate nitro-oxides from a kerosene flame like you could from a hydrogen flame.

How come hydrogen wouldn't produce nitrous oxides? As far as I know all it takes is nitrogen and oxygen (both present abundantly in air) as well as very high temperatures (which you would still have in a hydrogen flame).
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Oryx
Posts: 123
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RE: Biofuels In Aviation - A Possible Alternative?

Wed Jan 11, 2006 8:35 pm

You have to compromise the layout of the combustion chamber between the production of unburned carbohydrates and nitro oxides. Without the presence of carbon in the fuel you can optimize for low nitro oxides with big improvements over present combustion chambers.

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