[TheForge] OT biodiesel now hydrogen

[Grover Richardson]

Problem is that internal combustion engines burning hydrogen are also
susceptable to the same polution outputs as gasoline, but to somewhat of a
lesser extent.  Reason is the high compression during combustion.  Nitrogen
just loves to combine with things at high temperatures and pressures<G>.

Second problem is safety.  Hydrogen is combustible from roughly 8 to 88
percent in the air (from memory), whereas gas requires a narrow range for it
to happily mate with oxygen<G>.  The rules for handling hydrogen are
horrendous.  We are building a facility here to run and test 50 kW fuel
cells.  Stainless steel pipes, special runs with gratings through the
parking lot.  When it goes through a ceiling, it has to be overlaid with a
secondary containment system pipe, filled with a neutral gas, and monitored
electronicly for leaks.  We recently build a battery lab where, we currently
have students doing PHd work with fuel cells.  We can only put two 52" tall
by 9" diameter tanks of hydrogen in the lab, or we have to have even more
extreme safety measures (IE rebuild the lab) in order to place more tanks in
there.

We have a 3.5 horsepower fuel cell.  It's 47 x 27" x 24" (me walking over to
measure the beast as I write<G>).  This includes the computer to run it and
make it happy, but NO nitrogen tank (for purging) or hydrogen tank.  This is
the size of a lawn mower engine in power output.  Add that to the fact that
the average fuel cell costs about 10 times the cost of an internal
combustion engine, for equivalent output power, and you may see the problem.

Running at near full 3.5 horsepower, it sucks down a 52" x 9" tank of
hydrogen in about 45 minutes.  Supplying the beast with hydrogen at
meaningful output powers is a problem.  For the 50 kW fuel cell work, they
will have to install a feeding station in the parking lot which will require
quantity 2 of 18 wheel truck trailers in order to run the fuel cell at
meaningful power levels.  And they will have to be changed out almost daily
(I don't remember the exact number here).

If you feed a fuel cell too much hydrogen, and do not pull off the power,
you waste combustible fuel/air mixture to the air.

If you feed it, and try to pull off too much power, the computer shuts it
down so that it will not be hurt.  Not good.  It takes about 5 minutes for
it to cycle.

Fuel cells require an even distribution of gasses within the plates.  Each
plate in the 3.5 horsepower unit makes roughly (generally speaking) 1 Volt.
So, this particular fuel cell (all I have seen so far are made similarly)
has over 150 cells in series parallel, each about 14" square and about
0.050" in thickness (this makes up about 35" in length, including end pieces
and inter cell feed pieces).  They are spring loaded to assure even loading.
Placing such a device in a moving vehicle has yet to be done successfully in
a commercial setting (anyone know if they have and I just don't know about
it????).

Some Scandinavians did a study on hydrogen infrastructure.  Doesn't look
good.  The molecule is so small that trucks would likely go back with a
percentage of it's load, due to the difficulty of removing the last few
dregs.  Changing it into liquid doesn't help much as the viscosity of the
gas is slightly more than the liquid<G>.

We study, and work on fuel cells and vehicles here.

IMHO, what will happen is that even when gasoline dissappears off of the
face of the earth, hydrogen and other materials will be used to make a
gasoline equivalent.  You can't beat it for power density and ease of
transport<G>.  Possibly the same could be said of diesel also.

Oh yes.  We also built a hydrogen bus for the Olympics when they were in
Atlanta.  We used beds, not catalytic though.  However, it was necessary to
heat the bed artificially in order to liberate the hydrogen.  There is a lag
effect here.  In that you wish to liberate hydrogen as it is used, but what
happens when you start going up the side of a mountain.  There is a lag in
power as the beds come up to temperature and begin to supply more power.

In addition, the hydrogen available was insufficient for more than a single
run.  Refilling the beds is somewhat time consuming.  So you need more buses
to run while half the fleet (or more) is sitting at the breakfast bar<G>.

If a person is going to use electrolysis to liberate hydrogen in a vehicle
(or at home), it would seem more efficient to just go ahead and use an
electric motor<G>.

I stand by for comments<G>.

-----Original Message-----
From: theforge-bounces at mailman.qth.net
[mailto:theforge-bounces at mailman.qth.net] On Behalf Of debmiller at fuse.net
Sent: Thursday, May 26, 2005 7:22 AM
To: Sponsored by ABANA
Subject: Re: Re: [TheForge] OT biodiesel


Burning oil is not the long term answer. In my view the long term answer
centers around a Hydrogen fueled economy. Electrolysis generated hydrogen,
embedded in catalytic beads, burned in engines and producing water as
emissions. The power to perform the electrolysis would be nuclear, either
fusion energy, if we ever get serious about it, or graphite core pebble bed
reactors.

The oil concerns would be reduced to secondary markets as suppliers of
non-synthetic lubricants..........

Ray
Cincinnati