Re: Global Warming: Junk science at it's [best] worst

In <qanre353q5o2jcmat1htm2gg7p0844qmfa@xxxxxxx>, Jonathan Kirwan wrote:
On Sun, 16 Sep 2007 21:06:35 +0000 (UTC), don@xxxxxxxxxxxxxx (Don
Klipstein) wrote:
<SNIP to edit for space>

To have equal energy content, a quantity of liquid hydrogen would have
almost 4 times as much volume as kerosene, but 1/3 the mass.

Last year, I was helping prepare a few slides for my son in high
school on the subject of hydrogen as a fuel supply for transportation.
Two tables from that report are interesting:
I add density kg/liter:
Fuel Energy Comparison (calc. from 1st 2 columns)
------------------------------------------------------------------------
MJ/kg Total MJ/liter H2 MJ/liter
------------------------------------------------------------------------
H2, 20K cryogenic 120 8.4 8.4 .07
H2, 150K cryogenic 120 3.5 3.5 .029
H2, 5000 psi, ambient 120 2.75 2.75 .0229
H2, 3600 psi, ambient 120 2.0 2.0 .0167
Methane 50 21.0 12.6 .42
Ethane 47.5 23.7 12.0 .491
Propane 46.4 22.8 10.6 .491
Gasoline 44.4 31.1 13.2 .700
Ethanol 26.8 21.2 12.3 .791
Methanol 19.9 15.8 11.9 .794

The last column in the above chart represents the H2 portion of the
available energy. Obviously, for hydrogen, the last two columns are
identical since 100% of hydrogen's energy is hydrogen. In the case of
the carbon based fuels, hydrogen is only one part of the total energy
from burning with O2.

I do want noted that all of these fuels, except for hydrogen other
than 20 K, appear to me to be shown in liquid form the way the densities
appear.

Keep in mind that methane has critical temperature far below room
temperature and cannot be liquified at any pressure at room temperature.
Also that ethane has a critical temperature of 32.3 degrees C, and for
all practical purposes can only be kept liquid in an idustrial or
transportation setting with cooling.

Another item worth comparing - liquified natural gas, with all per-liter
figures probably close to those of liquified methane and ethane. Also
impractical to keep liquid without cooling, probably explains why more
vehicles use propane, gasoline, diesel, methanol and ethanol.

This chart below, too:

Energy Density Chart
-----------------------------------------
MJ/kg MJ/liter
-----------------------------------------
Batteries 1 1
Pressurized H2 2 2
Hydrides 5 4
Liquid/20K-cryo-H2 8 8
Gasoline 38 27

This one was actually used to make an illustrative graph. It shows
clearly the difficulty we face in replacing gasoline for vehicles.
Carbon is very effective at helping to pack hydrogen into smaller
containers and it provides its own source of energy, as well. It is
tough to beat.

I thought the main selling points of hydrogen were that it is
carbon-free and can be produced with electricity. Depending on how much
we want to pay for transporting and storing it, it could look good where
it outperforms batteries.

- Don Klipstein (don@xxxxxxxxx)
.

Relevant Pages

  • Re: Low Cost Hydrogen is here to stay
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    (sci.energy.hydrogen)
  • Re: ETHANOL OR METHANOL?
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    (sci.energy)
  • Why We Need The Solar-Hydrogen Economy Now
    ... chemical engineer and nuclear engineer. ... Today's energy systems did not arise ... Fuel combustion from automobiles and power plants is the primary source ...
    (sci.energy)
  • Why We Need The Solar-Hydrogen Economy Now
    ... chemical engineer and nuclear engineer. ... Today's energy systems did not arise ... Fuel combustion from automobiles and power plants is the primary source ...
    (sci.energy)
  • National Geographic Article on the Future of Energy
    ... that 1,285 watts of power are blasting straight from the sun into my ... The euphoria of energy freedom is addictive. ... Is there such a fuel? ... wind, solar, even nuclear, to name a few. ...
    (sci.energy)