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Roland Paterson-Jones
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 Posted: Mon Dec 22, 2003 5:09 am Post subject: Re: Hydrogen from sugar water ( Onboard production ). |
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"Don Lancaster" <don@tinaja.com> wrote in message
news:3FE329F4.69123B1C@tinaja.com...
[quote]T Rex wrote:
Hydrogen on demand by Onboard reforming ( Using sugar water ).
And the energy density of sugar water is?
I would seriously doubt that it could even approach ONE watthour per
liter.
Compared to gasoline, your tank would have to be 9000 times larger.
[/quote]
Don, you>re way out.
We covered this in a loony thread on running an ICE on sugar water. The
energy density is surprisingly good.
"OK, C12H22O11, saccharose, has enthalpy of formation of 5166.2 kJ/mol. By
comparison, C12H26, n-Dodecane has enthalpy of 7518.8 kJ/mol. Of course,
C12H26 has molar mass of 170kg/kmol, whereas C12H22O11 has molar mass of
342kg/mol.
Add to that, the solvent, water, at 50% per weight, and saccarose/water
solution has 1/4 the energy/mass of dodecane.
Latent heat of vaporization of water is 2257kJ/kg. Molar mass of water is 18
kg/kmol. Latent heat of vaporization is 2257kJ/kg * 18kg/kmol = 40.6kJ/mol.
Solution of 50% by weight is 1 mol C12H22O11 to 342/18 mol H2O = 19 mol H2O.
So, we waste 40.6kJ/mol * 19 mol = 771 kJ in vapourising the H2O solvent,
while burning 5166.2 kJ of C12H22O11."
9000 times? No, close to 1/4 times _diesel_ energy density.
Try another tack, Don!
Roland |
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Roland Paterson-Jones
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| Posted: Mon Dec 22, 2003 8:20 am Post subject: Re: Hydrogen from sugar water ( Onboard production ). |
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"Don Lancaster" <don@tinaja.com> wrote in message
news:3FE329F4.69123B1C@tinaja.com...
[quote]T Rex wrote:
Popular Science.
Hydrogen on demand by Onboard reforming ( Using sugar water ).
Imagine pulling up to a Texaco station and pumping your SUV full of
sugar water. If a new hydrogen fuel cell idea takes off, someday you
might be doing just that.
And the energy density of sugar water is?
I would seriously doubt that it could even approach ONE watthour per
liter.
Compared to gasoline, your tank would have to be 9000 times larger.
[/quote]
Don, in this case you are out by three orders of decimal magnitude.
Check my post lower down in the thread.
Roland |
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Jeff
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| Posted: Mon Dec 22, 2003 12:06 pm Post subject: Re: Hydrogen from sugar water ( Onboard production ). |
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"Roland Paterson-Jones" <roland@rolandpj.com> wrote in message
news:bs596k$i50$1@ctb-nnrp2.saix.net...
[quote]
"Don Lancaster" <don@tinaja.com> wrote in message
news:3FE329F4.69123B1C@tinaja.com...
T Rex wrote:
Hydrogen on demand by Onboard reforming ( Using sugar water ).
And the energy density of sugar water is?
I would seriously doubt that it could even approach ONE watthour per
liter.
Compared to gasoline, your tank would have to be 9000 times larger.
Don, you>re way out.
We covered this in a loony thread on running an ICE on sugar water. The
energy density is surprisingly good.
"OK, C12H22O11, saccharose, has enthalpy of formation of 5166.2 kJ/mol. By
comparison, C12H26, n-Dodecane has enthalpy of 7518.8 kJ/mol. Of course,
C12H26 has molar mass of 170kg/kmol, whereas C12H22O11 has molar mass of
342kg/mol.
Add to that, the solvent, water, at 50% per weight, and saccarose/water
solution has 1/4 the energy/mass of dodecane.
Latent heat of vaporization of water is 2257kJ/kg. Molar mass of water is
18
kg/kmol. Latent heat of vaporization is 2257kJ/kg * 18kg/kmol =
40.6kJ/mol.
Solution of 50% by weight is 1 mol C12H22O11 to 342/18 mol H2O = 19 mol
H2O.
So, we waste 40.6kJ/mol * 19 mol = 771 kJ in vapourising the H2O solvent,
while burning 5166.2 kJ of C12H22O11."
9000 times? No, close to 1/4 times _diesel_ energy density.
[/quote]
Now add the fact that the combiner/fuel cell/electric motor system is more
efficient, and you get about a even better number. I did a couple of quick
calc>s in another post in this thread and got 1.5 to 2L of sugar water to 1
L of gasoline taking into account that gasoline has lower energy, the better
efficiency then a ICE, and a few assumptions about the sugar mix.
[quote]
Try another tack, Don!
Roland
[/quote] |
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root/administrator
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| Posted: Wed Jan 07, 2004 10:04 am Post subject: Re: Hydrogen from sugar water ( Onboard production ). |
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T Rex wrote:
[quote]Popular Science.
Hydrogen on demand by Onboard reforming ( Using sugar water ).
Imagine pulling up to a Texaco station and pumping your SUV full of
sugar water. If a new hydrogen fuel cell idea takes off, someday you
might be doing just that.
The idea could solve a fundamental fuel cell problem: To travel any
useful distance, a fuel cell car would need to carry hydrogen gas
under pressure, requiring a heavy, bulky fuel tank. Some experimental
autos solve the problem by carrying liquid fuel and extracting
hydrogen from it on the run—a method called onboard reforming.
[/quote]
Why not just carrying a more simple and stable liquid that will produce more
ratio of Hydrogen: water (H2O)?
[quote]This new procedure, which produces hydrogen from glucose and related
carbohydrates, was developed by chemical engineers James Dumesic,
Randy Cortright and Rupali Davda at the University of
Wisconsin-Madison. A platinum-based catalyst breaks down the
carbohydrates into carbon monoxide and hydrogen gas. The carbon
monoxide reacts with water to produce carbon dioxide and more
hydrogen. Everything happens in one container, with the liquid
solution under pressure at a relatively low 400?F. That, according to
Cortright, makes it well-suited for onboard reforming in a fuel cell
car; other reforming methods, he says, have required temperatures four
times hotter.
Glucose is a renewable sugar. It is already mass-produced from corn
and can also be derived from many kinds of biomass waste. Response
from the auto industry is guarded. The process "has a lot of appeal,
but also has major challenges," says Tom Moore, head of
DaimlerChrysler>s Liberty and Technical Affairs Division. He points
out that "vast amounts of space" would be required to grow enough
plants to fuel America>s auto fleet. Still, the auto giant is
interested enough in the Wisconsin project to provide some funding for
further research.
[/quote]
--
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Mainlander
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| Posted: Wed Jan 07, 2004 1:43 pm Post subject: Re: Hydrogen from sugar water ( Onboard production ). |
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In article <yzLKb.763058$Tr4.2184590@attbi_s03>,
root@dev.null.dnsalias.net says...
[quote]T Rex wrote:
Popular Science.
Hydrogen on demand by Onboard reforming ( Using sugar water ).
Imagine pulling up to a Texaco station and pumping your SUV full of
sugar water. If a new hydrogen fuel cell idea takes off, someday you
might be doing just that.
The idea could solve a fundamental fuel cell problem: To travel any
useful distance, a fuel cell car would need to carry hydrogen gas
under pressure, requiring a heavy, bulky fuel tank. Some experimental
autos solve the problem by carrying liquid fuel and extracting
hydrogen from it on the run?a method called onboard reforming.
Why not just carrying a more simple and stable liquid that will produce more
ratio of Hydrogen: water (H2O)?
[/quote]
Ask yourself this question: why is most commercial hydrogen produced from
sources other than water, even though water is essentially free?
--
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Don Lancaster
Guest
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| Posted: Wed Jan 07, 2004 8:14 pm Post subject: Re: Hydrogen from sugar water ( Onboard production ). |
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Mainlander wrote:
[quote]
Why not just carrying a more simple and stable liquid that will produce more
ratio of Hydrogen: water (H2O)?
Ask yourself this question: why is most commercial hydrogen produced from
sources other than water, even though water is essentially free?
--
Full featured open source Win32 newsreader - Gravity 2.70
http://sourceforge.net/projects/mpgravity/
[/quote]
Because water is an ash and (because of fundamental chemical energetics)
is the WORST possible place to look for a hydrogen source.
See http://www.tinaja.com/energfun.pdf
The loss of exergy during electrolysis is staggering.
--
Many thanks,
Don Lancaster
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
voice: (928)428-4073 email: don@tinaja.com fax 847-574-1462
Please visit my GURU>s LAIR web site at http://www.tinaja.com |
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