Newsgroup sci.energy.hydrogen 4609

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Evert ROSSEEL wrote:
> 
> This value is wrong. The RON of methane is about 130.
> Carburants et Moteurs (J.C. Guibet) gives a RON of 60.
> (I do have another ref. in a specific hydrogen article giving nearly
> the same value, but I would need to look this up.)
>
Looks like we got a real scientific dispute about the octane rating of 
hydrogen going on here.
Just for the statistics: I have three references claiming an octane 
number of 130 for a stoichiometric A/F ratio (C.F.Taylor and two 
different articles by L.M.Das) and one claiming 60 (some German guy, 
maybe Peschka, I'd have to look it up). 
To me it seems that there is truth in both those numbers, depending on 
how you look at it.
I agree, talking about gaseous fuels the methane number would be the 
proper thing to talk about, but anyway, if I was to compare the octane 
number of hydrogen and gasoline, I might as well stick to this number.
As far as I got, the octane rating is being done in a standardized 
engine including a intake system which might not be suited for hydrogen 
at all. This would explain a relativly low ON of 60.
But on the other hand, the ON tells me something about a fuels 
resistancy to autoignition. Autoignition depends on temperature and 
pressure for a given A/F ratio. And these values are considerably higher 
for hydrogen than for gasoline. Therefore a high ON of 130 sounds 
reasonable to me.
I would assume that those standard engines used to determine the ON are 
just not adequate for hydrogen. If I'm wrong, would somebody please let 
me know. Any useful information is apreciated.
> 
> To operate with a compression of 15, the maximum richness is somewhat
> above 0.5, which is much less than is possible with a compression of
> 10 for
> instance. This means also that maximum power is reduced (mixture
> contains less hydrogen then possible with a lower compression ratio).
> 
Well, at least one of the ideas out there is to go as lean as possible 
since it decreases the maximum temperature which accounts for extremly 
low NOx. We are doing some research on an engine for a Hybrid Electric 
Vehicle (HEV). The engine 2.2 l and puts out 36 hp at 3000 rpm. That's 
not a lot, but perfectly suited for our purpose. I'm not quite sure if 
we will have to go any richer than an equivalence ratio of 0.5 or 0.6 at 
all. So a compression ratio of 15:1 might all right. We expect to meet 
at least the ULEV standards.

Casey Lee Lengacher wrote:
> 
> I would just like to warn you that the thinking that a hydrogen driven car
> doesn't produce carbon monoxide or dioxide is incorrect unless both sources
> of hydrogen and oxygen come from highly purified sources and the combustion
> chamber is closed from the outside system. If you are supplying oxygen from
> atmosphere, you will get various NOx and COx.
You won't if you use a fuel cell!
Cheers,
-- 
William R. Stewart
http://www.patriot.net/users/wstewart/first.htm
Member American Solar Energy Society
Member Electrical Vehicle Association of America
"The truth will set you free:  - J.C.
"Troll:
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Casey Lee Lengacher wrote:
> 
> I would just like to warn you that the thinking that a hydrogen driven car
> doesn't produce carbon monoxide or dioxide is incorrect unless both sources
> of hydrogen and oxygen come from highly purified sources and the combustion
> chamber is closed from the outside system. If you are supplying oxygen from
> atmosphere, you will get various NOx and COx.
You won't if you use a fuel cell!
Cheers,
-- 
William R. Stewart
http://www.patriot.net/users/wstewart/first.htm
Member American Solar Energy Society
Member Electrical Vehicle Association of America
"The truth will set you free:  - J.C.
"Troll:
     A deliberately disrupting, confused and incorrect
     post (or one posting trolls) to a Usenet group to
     generate a flurry of responses from people called 
     "billygoats" trying to set the record straight.
     Other trollers enter the fray adding more and more
     misinformation so that the thread eventually dies of
     strangulation.  Trolls/trollers cannot be affected
     by facts or logic."    - bashford@psnw.com

Please can someone point me at a reference to the proposal to build 
extremely tall hollow towers (like giant cooling towers), and use air 
currents within them to generate electricity.
I think the team developing the idea are based in Israel, but I've failed 
to find anything relevant with web searches. The idea got some media 
coverage a couple of years ago.
Alan T.
(agt@eatl.co.uk)

I am not the worlds' greatest chemist.  Could someone please tell me
the energy ballance in creating solar water gas?
Steam could be heated in a high temperature focusing collector to
approx. 1200 deg. f., then reated with carbon.
Reaction:  C + H2O  = CO + H2
When the heat is supplied BY heating the steam, rather than burning
some carbon, what is the energy ballance?
How much heat comes from the sun, and how much from the partial
combustion of the carbon?
It seems to be that such a system is practrical and doable.  While not
100% solar energy, it is at least partly renewable.  
Also, the output gas will contain no nitrogen nor carbon dioxide, and
could be used as synthesis gas for methanol production.
A curious mind wants to know...
Gene A. Townsend