Naked Science Forum
Non Life Sciences => Technology => Topic started by: Tintin_Triton on 28/09/2009 07:46:05
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I was watching the Singapore Grand Prix yesterday, and suddenly this thought came into my mind : What if we can provide some better fuels than they use there? I was looking towards Hydrogen, but then it occurred to me that it does not provide enough power per litre.
Can anyone tell me of the fuels that can be less polluting, and yet more efficient than petrol?
Thanks!
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Liquid Oxygen would be the best fuel and it's clean by product being water.
Producing the Liquid Oxygen and super cooling it in the first place likely takes a lot of energy ruining the green part.
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Oxygen burns?
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"Can anyone tell me of the fuels that can be less polluting, and yet more efficient than petrol?"
If I knew the answer to that, I would be rich beyond my wildest dreams. So I wouldn't be telling you, or anyone else, anything about it.
Does anyone know where the starship Enterprise gets it's dilithium crystals from?
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"Can anyone tell me of the fuels that can be less polluting, and yet more efficient than petrol?"
If I knew the answer to that, I would be rich beyond my wildest dreams. So I wouldn't be telling you, or anyone else, anything about it.
Does anyone know where the starship Enterprise gets it's dilithium crystals from?
LOL....
That is true. But it just came into my mind to use hydrogen, highly compressed one; through the use of solar cells.
Hydrogen can readily burn, and producing it is easy!
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Also, did anyone see Iron Man the movie? His Arc Reactor is the answer to all of our power woes!
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"Can anyone tell me of the fuels that can be less polluting, and yet more efficient than petrol?"
If I knew the answer to that, I would be rich beyond my wildest dreams. So I wouldn't be telling you, or anyone else, anything about it.
Well, you need to add one more prerequisite to that:
Less polluting and more efficient for a similar large-scale production cost!
If money isn't much of a concern (as in F1) I would have thought a chemical like 2,5-Dimethylfuran could be substituted. 2,5-DMF can be derived from plant fructose and cracked in processed very similar to petrochemicals, but with potentially very low carbon impact. The energy density of 2,5-DMF is almost equal to petrol so could fuel an F1 car with minimum additives.
With no reliance on biological processes, unlike ethanol or n-butanol (another good contender for F1 fuel), 2,5-DMF can be easily scaled up without the worries of process infection.
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F1 would be much more efficient and green if they filled the fuel tanks with water.
Admitedly the cars wouldn't go anywhere but driving round in circles very fast just to get back to the starting line is so far from green that the idea of "green F1" is implausible.
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I was watching the Singapore Grand Prix yesterday, and suddenly this thought came into my mind : What if we can provide some better fuels than they use there? I was looking towards Hydrogen, but then it occurred to me that it does not provide enough power per litre.
Can anyone tell me of the fuels that can be less polluting, and yet more efficient than petrol?
An example is methyl alcohol. It has an higher power for unit volume of air/fuel mix (at stoichiometric concentration, of course); furthermore it cools more the mix when vaporizes so the mix is denser and you can go to higher revs for the increased cooling; furthermore, the octane number of CH3OH is higher than that of gas and so you can use higher compression ratios (and increase the thermodynamic efficience)
http://en.wikipedia.org/wiki/Octane_rating
The problem is that the consumption is more than doubled with CH3OH. Without changing compression ratio and ignition time, but only the amount of fuel, I experimented, among others, methyl alcohol in my byke when I was (much) younger. Speedway bykes use that fuel too.
http://en.wikipedia.org/wiki/Motorcycle_speedway
and race cars at Indianapolis, before 2006, used pure methanol as fuel.
Ethyl alcohol is good too but is less efficient.
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It's slightly ironic that Indy 500 cars used to run on methyl alcohol, which is, arguably, a lot "greener" (I really hate that term!) than gasoline because you can produce it from all kinds of junk. If I remember correctly, methyl alcohol is a wee bit corrosive in some circumstances, but the problems are not too difficult to overcome.
Methyl alcohol could be a very good substitute for gasoline if it is synthesized from a non-fossil energy source. We would need larger fuel tanks on our vehicles, but that seems like a small price to pay if it stops the increase of CO2 in the atmosphere.
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Methyl alcohol could be a very good substitute for gasoline if it is synthesized from a non-fossil energy source. We would need larger fuel tanks on our vehicles, but that seems like a small price to pay if it stops the increase of CO2 in the atmosphere.
Here's a table showing the energy densities of some fuels:
==== Fuel type ===== ============ Energy density ===========
By Mass (MJ/kg) By Volume (MJ/L)
Gasoline 46.4 34.2
Kerosene 42.8 33
Vegetable oil 42.20 33
DMF (2,5-dimethylfuran) 42 37.8
Butanol 36.6 29.2
Ethanol 30 24
Methanol 19.7 15.6
On the bases of weight & space of the fuel tank alone, I can't see why any race car/bike would get an advantage from running on Methanol (methyl alcohol).
Plain old veg oil looks good on these figures, but (like Diesel) the flame rate is too slow for high-revving race engines.
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Methyl alcohol could be a very good substitute for gasoline if it is synthesized from a non-fossil energy source. We would need larger fuel tanks on our vehicles, but that seems like a small price to pay if it stops the increase of CO2 in the atmosphere.
Here's a table showing the energy densities of some fuels:
==== Fuel type ===== ============ Energy density ===========
By Mass (MJ/kg) By Volume (MJ/L)
Gasoline 46.4 34.2
Kerosene 42.8 33
Vegetable oil 42.20 33
DMF (2,5-dimethylfuran) 42 37.8
Butanol 36.6 29.2
Ethanol 30 24
Methanol 19.7 15.6
On the bases of weight & space of the fuel tank alone, I can't see why any race car/bike would get an advantage from running on Methanol (methyl alcohol).
Plain old veg oil looks good on these figures, but (like Diesel) the flame rate is too slow for high-revving race engines.
It's for this reason that I specified "It has an higher power for unit volume of air/fuel mix". In an internal combustion engine is not so important the energy per unit mass or unit volume of the liquid fuel, like in your table; what counts is the energy per unit volume of air/fuel mix. In italian is called "tonalità termica", I haven't found the translation into english.
At stoichiometric concentration, the methanol mass inside the cylinder is more than double the mass of gasoline because an equal volume of oxygen requires much more mass of methanol for a complete cobustion, so the energy released is more than double the amount written in your table. The result is that the energy released in every cycle is greater for methanol:
Fuel energy per unit volume of fuel/air mix (KJ/litre)
gasoline ................ 3.73
ethanol ................ 3.85
methanol ................ 3.90
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Ah ha!
See, I knew it all along Peppercorn. You're full of it. Figure that out! [;D]
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It's for this reason that I specified "It has an higher power for unit volume of air/fuel mix".
...the methanol mass inside the cylinder is more than double the mass of gasoline...
Yes, I agree. You'll notice that I was focusing on fuel storage as an issue, not power delivered. I am not trying to discredit the use of methanol in racing - it clearly has some major benefits as you've suggested.
On the bases of weight & space of the fuel tank alone, I can't see why any race car/bike would get an advantage from running on Methanol (methyl alcohol).
As I implied, my 'gut feeling' was that such a reduction in energy density would 'cost' too much in terms of added weight of overall vehicle, the larger aerodynamic drag and the need to refuel more often. Considering we started talking about F1 & refuelling is now a major strategic area this is a good possible reason why we'll never see methanol fuelled F1 cars.
Looking at the closeness of the energy per unit volume of fuel/air mix you've given, I suspect the real reason methanol is preferred has more to do with its high octane rating - allowing engines to run at very high boost.
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See, I knew it all along Peppercorn. You're full of it. Figure that out! [;D]
Your right! I'm certainly full of something!! Can't mention what it is on TNS forum though!!! [:I]
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Why do jets run on kerosene? Is it because of its "tonalità termica"?
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As I implied, my 'gut feeling' was that such a reduction in energy density would 'cost' too much in terms of added weight of overall vehicle, the larger aerodynamic drag and the need to refuel more often.
If you refill more often you don't need a bigger tank [:)].
Considering we started talking about F1 & refuelling is now a major strategic area this is a good possible reason why we'll never see methanol fuelled F1 cars.
Probably a greater problem than that is the fact that when methanol burns, the flame is almost invisible, and this is a danger at the boxes.
Looking at the closeness of the energy per unit volume of fuel/air mix you've given, I suspect the real reason methanol is preferred has more to do with its high octane rating - allowing engines to run at very high boost.
No, it's not the only one, the others I mentiond are important too: greater energy for unit volume of the mix and so greater power for every cycle only for this reason; greater density of the mix because of the greater cooling (methanol has an higher vaporization enthalpy) and greater cooling of the engine for the same reason (which allows higher revs or greater turbo pressures).
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If you refill more often you don't need a bigger tank [:)].
Smart-arse!!! [;D]
It's slightly ironic that Indy 500 cars used to run on methyl alcohol, which is, arguably, a lot "greener".
Assuming Indy 500 cars no longer run on methanol, why did they stop & what do they run on now?
If Butanol or DMF were readily available (from renewable sources) would they make good F1 fuels?
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It's slightly ironic that Indy 500 cars used to run on methyl alcohol, which is, arguably, a lot "greener".
Assuming Indy 500 cars no longer run on methanol, why did they stop & what do they run on now?
They use ethanol now. Don't know why they stopped.
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Why do jets run on kerosene? Is it because of its "tonalità termica"?
Jets uses kerosene _essentially_ because they need a fuel which doesn't freeze at very low temperatures.
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Ah, I see.
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Why do jets run on kerosene? Is it because of its "tonalità termica"?
Jets uses kerosene _essentially_ because they need a fuel which doesn't freeze at very low temperatures.
Why not gasoline? It's got a low freezing point too.
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http://en.wikipedia.org/wiki/Jet_fuel
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Quote from above link:
"The first jet fuels were based on kerosene or a gasoline-kerosene mix, and most jet fuels are still kerosene-based."
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Quote from above link:
"The first jet fuels were based on kerosene or a gasoline-kerosene mix, and most jet fuels are still kerosene-based."
Which is not gasoline only...
Anyway, if you have another theory, you can express it.