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This is part 2 of a ongoing speculation about how a liquid air-powered
automobile engine might be improved over current schemes, which is simply to
expand the liquid through a turbine or reciprocating engine using ambient heat
to get the 800 to one expansion ratio. But there is potential unused energy in
the liquid air itself, which can be exploited - of both the chemical and
Casimir-related varieties.
First of all and most obviously, it should be re-affirmed and hoped that CF
or ZPE conversion technologies will negate any need for this, but on the chance
they are delayed, or run into a cost (Pd) or technological dead-ends for unknown
reasons, then it is wise to be prepared with secondary options, should we reach
the stage where carbon can no longer be considered a tolerable fuel.
This will assume that we have gone to 100% non-carbon electricity through
the use of improved nuclear, wind and solar energy over the grid - and that
legislation has forced all carbon to be consumed in the form of structural fiber
and plastics. At this stage, improved batteries or hydrogen fuel would
normally be considered the best choices for transportation.
In any event, if we are forced to use nuclear energy for the bulk of our
consumption, it is wise to use the off-peak (night-time) hours to produce
transportation fuel or to charge batteries at the local (household) level.
Batteries make the most sense, if they can be improved as much as claimed, but
these same claims have been made for at least two decades and still the
lead-acid battery has not been replaced. Hydrogen may have storage and safety
issues for home manufacture. Therefore, nitrogen chemistry and
liquid cryo-fuel is not ruled out, based solely on apparent issues.
There is also the possibility of air/battery hybrids.
Under this scenario, 8-10 years out from the present, I think it
can be shown that liquid air has advantages over even burning hydrogen, in terms
of both cost and safety. The toxicity problems of this suggestion are apparent
in the "uncontrolled" chemistry of nitrogen, but these have already been solved
in principle with catalysis, so the bottom line is that this is another option
to consider to avoid global catastrophe from CO2 increase.
Nitrogen forms easily reversible oxides in which nitrogen exhibits each of
its positive oxidation numbers from +1 to +5. Nitrogen (di)oxide is a reactive
toxic compound released from auto exhaust that is easily converted by catalysis
to the base elements. These oxides are also produced naturally by the human body
and all life, so toxicity is often a matter of quantity, not quality. Dentists
use nitrous oxide N2O for "pain free" oral torture and kids use it to get
high. In all of these cases, oxides of nitrogen have a large fraction of an eV
of energy to "play with" in reversible energy content. This is compared to a
tiny fraction of an eV for ambient heat to be used in expansion. More on those
details in a later post.
Nitrogen oxides, or NOx, is the generic term for the entire group of highly
reactive gases which contain nitrogen and oxygen in varying amounts. Gaseous
nitric oxide is the most thermally stable oxide of nitrogen and is also
paramagnetic-- i.e., a molecule with an unpaired electron. At room
temperature nitric oxide is a colorless gas consisting of diatomic molecules.
However, because of the unpaired electron, two molecules can combine to form a
dimer by coupling their unpaired electrons.
2NO <--> N2O2
Thus, liquid nitric oxide is partially dimerized, and the solid consists
solely of dimers. Like with water/ice, therefore, there is a substantial density
variation between the solid and liquid, implying that the Casimir force can be
exploited by forcing expansion stresses to form explosively thorough either
rapid (microsec) freezing or thawing of the nano-particulate. Nitrogen oxides
form when fuel is burned at high temperatures, as in a combustion process, but
they can also be formed catalytically and then used as fuel. That is one reason
why NOx is formed naturally in almost all of life - it does provide a reversible
energy pathway and energy storage medium.
Some of the technology details are still classified, but many rockets and
rocket-boosters have employed nitrogen tetroxide as oxidizer/fuel. The
Titan was one such beast, and one can only speculate as to the full details, but
it seems clear that many nitrogen oxides will "burn" on their own at far less
output but with no need of carbon. IOW they will give us a half to a whole eV
per molecule on their own.
If one is expanding a liquid to a gas and through a turbine, then the
Carnot efficiency and energy density is limited by the ambient temperate of no
more than a tiny fraction of an eV. If we can multiply that 10-fold through
reversible nitrogen chemistry, then the net energy density of the fuel can be
increase to where it is arguable competitive or even superior to other methods
as a transportation fuel/storage medium.
This is the niche that needs to be looked-at more closely.
Jones
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