Re: Solar-hydrogen home power system?

From: Don W. (dNOSPAMwiddersAThotmail.com)
Date: 11/01/04 

Date: Mon, 1 Nov 2004 11:11:38 -0800

"George William Herbert" <gherbert@retro.com> wrote in message
news:4182acf4$0$33072$c0de7616@newsreader.dsl.net...
...snipped throughout at my own indiscretion:
> ...But I have worked with
> it enough (space applications primarily, but at the
> related-field-curiosity level ground and ground transportation
> power issues) to understand it and believe that it's
> a viable solution for transportation energy storage.
>

If you believe that hydrogen is a viable solution for transportation energy
storage, then you don't understand it. Hydrogen, storage devices and fuel
cells will always be too expensive to become practical transportation
energy storage systems. Extreme cold and extremely high pressure gasses
significantly increase safety hazards. Your grandmother probably doesn't
fill up the Studabaker with any kind of cryogenic fuel or any fuel
pressurized to 10,000 psi. Would you want her to? Would you want
everyone's grandmother and teenaged son to do so?

> >> In the San Francisco / San Jose area (SF Bay Area) you see
> >> just about as many tanker trucks full of LH2 (about ten
> >> cubic meters per trailer) as you do propane out on the
> >> freeways.

That simply isn't true. You also imply that the risks are the same and
they are not. More LH2 is delivered to the refineries than to the
semiconductor manufacturers, but there is far more propane tranported
because everyone uses propane for everything from the torch to the camp
stove to the backup generator. Only the refineries, fertilizer makers,
semiconductor manufacturers, margerine manufacturers and NASA are using
hydrogen. By far, the biggest user is NASA. LH2 has its own special
risks, but compressed hydrogen trucks are easy to distinguish from propane
tankers. The propane tankers usually have one very large tank. Compressed
hydrogen trucks have many long, cylindrical 'tubes' (this is a safety
requirement.)

> >> Hydrogen is used in bulk in semiconductor
> >> processing. I can't recall hearing of any accidents with
> >> hydrogen tankers.

http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=6868081
http://www.failure-analysis-consultant.com/case_html/Refinery-Hydrogen-Fire.html
http://www.ch2bc.org/bulletin/bulletin_1993.htm

Hydrogen accidents DO happen and people die. Those people are trained
professionals because virtually all hydrogen is handled by trained
professionals. The number of persons who handle hydrogen is many orders of
magnitude smaller than the number of persons who handle gasoline or
propane.

> >> Several propane tankers have blown up
> >> for one reason or another in the last 20 years. Hell, we
> >> had a gasoline tanker explode in one of the bores of the
> >> Caldecott Tunnel a couple of decades ago, killing a couple
> >> of dozen people if I recall right.
>
> Don has repeatedly stated that the use and transportation
> of liquid hydrogen in bulk around urban areas would be
> an unreasonable safety risk.
>
> Don was apparently unaware that LH2 *is* routinely transported
> in bulk around urban areas, without any special transportation
> safety concerns other than those accorded any flammable substance
> or cryogen.
>

Don is well aware of LH2 that is routinely transported around urban areas
(although in terms of bulk, the amount is TINY in comparison to actual bulk
energy sources such as gasoline and propane.) "...without any special
transportation safety concerns other than those accorded any flammable
substance or cryogen" is a grossly ignorant statement.
http://www.praxair.com/praxair.nsf/0/b038cf0b757ed257852567c1004f0069/$FILE/p4603f.pdf

> For all I know, today we could have a tanker accident
> with LH2 on one of the local freeways and it could catch
> fire, or even under unlikely conditions cause an
> explosion. The risk and hazmat issues involved are
> clearly there. It's flammable and potentially explosive
> and it's a hard cryogen.
>

So why do you write something as ignorant as "LH2 *is* routinely
transported in bulk around urban areas, without any special transportation
safety concerns other than those accorded any flammable substance or
cryogen."?

> But it hasn't happened yet, despite me passing 1-2 tankers
> of it a day driving to and from work.
>

I don't believe that you pass 1-2 tankers of hydrogen everyday, but I could
be wrong here. The only source of LH2 for the Bay Area that I'm aware of
is Praxaire in Ontario (in Southern California.) IF that's the only
commercial source of LH2 in the Bay Area, and if you pass 1 or 2 of these
trucks to and from work every day, then the freeway around Ontario must be
clogged with LH2 trucks!

>
> >.Flow-induced static charge generation
>
> Also a risk with other combustable gases.
>

Not to the degree of hydrogen.

> >.Low viscosity (leaks easily)
>
> Also a risk with other combustable gases.

Not to the degree of hydrogen. Hydrogen literally slides between the
molecules of metal pipe!

>
> >.Odorless, colorless gas
>
> Could be odorized in the manner of propane.

Your ignorance is showing.

>
> Also, other colorless odorless combustable and potentially
> detonable gases are shipped in bulk. Deodorized propane is
> used industrially.

I don't agree with this. If there was no reason to oderize gasses, no one
would bother to oderize them.

>
> >Pressure .High pressure storage (2000 psig or
> >more) can result in pressure rupture,
> >flying debris
>
> So can any pressure vessel. Helium, anyone?
> It's shipped in high pressure tank trucks.
>

...not to the degree that is proposed for hydrogen because ordinarily there
is no need to pressurize vessels to 5,000 psi or even 10,000 psi. It is
generally agreed that 5,000 psi is minimum pressure for reasonable range
with a reasonable size tank for an automobile.

> >.Pipe whip concern with leak events
>
> So can any pressure vessel, risk proportional to
> the pressure, which is admittedly on the high
> side for gaseous stored hydrogen.

What exactly do you mean by "on the high side"? It's insanely high!
Terrible accidents have resulted from scuba tanks pressurized to 200 psi.

> >.Gas jet impingement on personnel is also
> >a hazard, high pressure can cut bare skin
>
> Common risk with any gas.
>

5,000 psi pressurization is not common, but it's a requirement for
reasonable energy density with hydrogen.

> >> Spilling LOX causes an equal or worse flammability
> >> hazard and can lead to substances as inert as asphalt
> >> and rubber tires out and out detonating, not just
> >> deflagrating. It boils much more slowly and the
> >> vapors typically stay near the ground, in clouds
> >> of high oxygen concentration that will burn organics
> >> and vehicles and buildings to ash and rust in
> >> short order if there's an ignition source nearby,
> >> such as a vehicle motor running.
> >
> >I don't remember anyone advocating a "LOX" economy?
>
> LOX is however shipped in bulk, is present at essentially
> any large medical facility in ton quantities, is used
> industrially in bulk in urban areas without special
> concerns for handling or transportation.

You're crazy if you don't think there are special concerns for handling or
transportation if LOX!

> It's even
> available to the general public with proper handling
> equipment.
>

I don't know of anyone in the general public using liquid oxygen. I can
also buy liquid hydrogen from Praxaire, but I don't know of any private
individuals doing so. Of course, if autos were fueled with hydrogen, then
hydrogen (whether liquid or highly compressed) would be as common as
gasoline!

Don W.

Relevant Pages

  • Re: Solar-hydrogen home power system?
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