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Mentioned earlier was the interesting hybrid
energy-cycle involving Zinc + solar,
developed by a cooperative of scientists from Israel, Sweden, Switzerland and France - which is efficient and relatively self-sustaining. The joint effort also defies the notion that all
such bureaucratic cooperatives are doomed to failure, for the normal
bureaucratic reasons being layered on top of PC.
This partial success seems like it could be the
best overall way of all solar-H2 methods, at least so far as what is publicly
known, including nuclear-thermochemical - to produce hydrogen economically and
ecologically -but it is far from optimum.
Still a lot of carbon is getting out (unless
biomass carbon is "discounted" in this regard - i.e. zero-net carbon release).
Zn is not expended in this process, but is reused. Zn operates more or less as a
catalyst for the next step - but producing Zn this way - with about half to 2/3
of the net refining energy coming from solar, the rest from biomass/coal is the
big change. Substantial coal or biomass is still required, even if it is only
half to 2/3 of what normally would be needed for Zinc refining - but here is a
suggestion which may eliminate some, or all, of that
carbon.
Remember the SOFC? The Solid Oxide Fuel Cell (SOFC) operates at high
temperature (1,000 degrees Celsius) and is rugged ceramic -
possibly capable of being used in a solar refining system at even higher
temps of 1200°C (2192F) but in the reversed way. (just as a PEM fuel cell can
split water, if reversed).
The main feature of the SOFC is the "exchange"
right THROUGH THE CERAMIC of O2- ions. This is quite an amazing feat, when
you think about it.
These ions could theoretically be "pulled" through
a thicker ceramic electrolyte reactor - made of doped zirconium dioxide - by a
tiny voltage differential applied to the reverse side - thereby eliminating
all the carbon (the electricity being supplied by adjoining solar cells or
solar-Stirling.
The powdered preheated ZnO ore, to be refined
in the reactor, would be admitted along with a gaseous carrier (He or Ar) into a
vortex type SOFC tube into which highly focused solar energy is being
irradiated.
At a heat of above 1200°C (2192F) the ZnO breaks
down minimally into Zn and negative oxygen ions, but at the lower temperature
- these reactive intermediates will in turn *recombine* immediately -
unless carbon is present to create CO or CO2... OR... ta-da....unless the O2
negative ions can be "drawn" through a solid electrolyte by a slight
positive charge. Possibly a tenth to a quarter-volt would be all which is
required at 1200°C . An adjoining Solar-Stirling unit can provide that. The
negative charge for the refined Zn comes at ground, so the total electrical
energy required is perhaps 10% of what electrolytic zinc would
need.
The biggest foreseeable problem
(after 30 seconds of contemplation) - "slagging" of the
tube.
Is it doable??
If so, the concept is now in the public
domain and you heard it first on vortex....;-)
Jones
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