NetNews Usenet Archive 1992 #27/NN_1992_27.iso/spool/sci/energy/5654

Internet Message Format | 1992-11-20 | 4.4 KB

Path: sparky!uunet!zaphod.mps.ohio-state.edu!darwin.sura.net!seismo!skadi!stead
From: [e-mail] (Richard Stead)
Newsgroups: sci.energy
Subject: Re: Any info. on hydrogen power for cars??
Message-ID: <[e-mail]>
Date: 20 Nov 92 21:33:45 GMT
References: <[e-mail]> <[e-mail]>
Sender: [e-mail]
Lines: 71
Nntp-Posting-Host: skadi.css.gov

In article <[e-mail]>, [e-mail] (Paul Houle) writes:
> In article <[e-mail]> [e-mail] writes:
> >Before hydrogen cars can ever be more than a "look at us, see how good
> >enviromentalists we are" project/publicity stunt, one major problem has
> >to be solved.  How do you generate all that hydrogen in the first place
> >without generating pollution, possibly more than running the car on gasoline
> >or some other alternate fuel in the first place?
> >
> >Also, you get NOx pollution when hydrogen is burned in an internal combustion
> >motor, the only way to make it so the "only by-product is water" is to use
> >it in a fuel cell (which is sensible anyway).
>
>     The currently most economical way to make hydrogen is from the coal gas
> process,  which also produces CO,  but the CO can also be burned to produce
> CO2 and quite a bit of energy,  so except for the CO2 emission,  this could be
> fairly clean.  Most people who talk about a hydrogen economy,  however,
> suggest that we make the hydrogen by electrolysis of water,  getting
> electricity from whatever they believe is an environmentally benign and
> potentially economical source:  nuclear energy,  ground-based solar,  wind,
> and solar power from space satellites have all been suggested.

Actually, electrolysis is not required.  Hydrogen can be generated pretty
efficiently just using heat and chemical reactions.  I did this in high school
15 years ago and showed that a series of reactions which reproduced the
starting chemicals and split water in the process would actually work.
Now as a high school kiddy, I did this using chemicals in a flask, a plastic
fresnel lens as a solar concentrator and transfered the products by hand.
I collected the hydrogen over water.  These methods are not practical for
a production system but clearly demonstrated the concept and potential.
The only thing needed is to put some Chem E's on the idea, and I'm sure
a production system could be made.  The heat source does not need to be
solar either - waste heat from a reactor would do fine.  The advantage of
solar heat is that it could be used where other energy sources are impractical -
at sea or on polar ice, for example.  But those applications would give
only small amounts of hydrogen - enough to run a cook stove or something
on a daily basis, but if processing ran continuous and fuel was accessed
only occassionally, you could conceivably have a lot.

>     So far as the NOx emissions go,  they can be reduced by changing the
> operating parameters of the engine (cylinder temperatures) and by other
> engineering tricks,  so that they could be much,  much,  cleaner than
> comparable gasolene-fuel vehicles.  Also,  photochemical smog is caused by

Is this true?  You can tweak a hydrogen-combustion system to produce less
NOx than with equal tweaking effort on gasoline?  Do you have data?  Also,
in this tweaking, does it come at the expense of efficiency?

> a combination of hydocarbons and NOx,  so simply reducing the hydrocarbons
> or the NOx alone could make a large contribution towards the reduction of
> smog and improving air quality.

Hard to reduce the hydrocarbons sufficiently - people animals and plants emit
them, too.  Reducing NOx is probably the best single answer and cutting
artificial hydrocarbon sources as much as possible.

>     I personally think that biomass fuels are more likely to be used
> in a sustainable economy -- with fuel cells,  one could get very close to
> zero emission (some CO2 gets released,  but it was just removed from
> the atmosphere in the past few years,  so this doesn't contribute to

Yeah, but the fuel cells probably produce some sort of foul acidic sludge that
must be dealt with if they are fed raw biomass.  If the bimass is first conerted
to alcohol or methane, then the convertor produces sludge.  Hopefully,
the sludge could be converted to fertilizer.


--
Richard Stead
Center for Seismic Studies
Arlington, VA
[e-mail]