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August 12th 05, 04:54 AM

wrote:
Michael Coslo wrote:

wrote:

Michael Coslo wrote:

What are the byproducts of converting seawater to hydrogen and oxygen?

Mostly salt.

And chlorine.

As you mentioned in another post, sodium hydroxide.

However I don't see that as a big problem. Either the electrolysis
process can be made to not split the NaCl, or it can be recombined and
the energy recovered.

The main byproduct problem I see is that you'll have lots of salt.

Hydrogen is seen as some sort of saving angel in the energy issue.
Producing the hydrogen is a bit of a problem though. It takes a lot of
energy to produce it. It has a pretty low volumetric energy density.

Which means it is compressed and your fuel tank becomes a highpressure
canister. Not only is the stuff flammable, like gasoline, but it's
under high
pressure.

Two ways to go boom.

But to the problem at hand, a somewhat practical method of producing H2
would be to electrolyze it, using Nuc power. The electrolysis plant
would probably be set up near the ocean (let's not even talk of fresh
water production - just ask the folks on the left coast about fresh water)

So now we have an extraction plant that is powered by an unpopular
power source, and has one big nasty polluting byproduct.

Or we can use the other methods of generating H2. Of course, they cause
as much pollution producing the fuel as if we just used the fuel in the
first place.

Maybe. There are all sorts of possible technologies to extract,
transport and store hydrogen. For example, there's work being done to
store the gas in metal hydrides. It could be extracted by using
electricity made photovoltaically. Etc.

The infrastructure would be interesting. The best looking way for
hydride storage that I've heard of so far, is the replacement tank
method. Interesting, and I suspect that teh real quick stop for fuel
would become a thing of the past.

Not with quick-connecting pipes. Leave it to the MEs.

I wonder if there will be self-tank exchange stations? 8^)

No doubt it can be done.

The big question is whether such processes can be made economically
competitive. How much will a hydrogen car cost? How much will they cost
to drive per mile? What are the maintenance costs?

Maintenance would *probably* be improved. I suspect that
engines would
last longer, and be a lot cleaner to be around.

Agreed!

But the cost competitiveness problem still exists.

The big problem is that there's probably no single magic long- term
solution. Rather there are a bunch of small solutions that add up.

Here's two favorites of mine:

Imagine a tall (couple of hundred feet) hollow tower, in the desert. A
vertical pipe, as it were, with holes around the bottom.

Around its base is a large circular greenhouse whose roof slants toward
the tower.

When the sun is out, the air under the greenhouse roof is heated, and
rises. This creates an artificial wind towards the tower. The warmed
air goes up the tower, which contains a wind-driven generator. Works
whether or not there is a breeze. The generator and its impeller are
near ground level. Etc.

Good process, and an old one. A lot of places in the middle east use
those type of towers (usually lower) to bring cooling air into the house.

The process also works for a limited amount of time after the sun goes
down. The warm ground heats the air above it.

The ground under the greenhouse roof can be farmed, if there's water
available for irrigation.

also

There's a process called TDP (Thermal Depolymerization Process) that
can supposedly break down various types of waste into fuel oil, gas and
other usable products. For example, there's a pilot plant here in
Philadelphia that takes sewage sludge (ugh) and breaks it down into a
type of fuel oil, methane gas, water, and some other things that are
usable as fertilizer. The result is also
sterilized.

If nothing else, it gets rid of the stuff!

Which is a major problem today. Two birds, etc.

Another plant in Carthage, MO, takes the waste from a turkey-processing
plant and extracts oil, gas and some other products from it.

The company claims that many other feedstocks can be used. Old tires, a
chronic disposal problem, can allegedly be broken down into oil, gas,
steel, fiberglass and carbon black.

The process supposedly uses 15% of the product to run itself.

hmm, not too bad...

*IF* it really does what is claimed. That's the problem with a
lot of new technologies:

One of the biggest problems I see for many of these technologies is that
they often don't have the scalability needed to provide fuel for many
vehicles, let alone fuel the countries needs. If this plant went into
serious production, it might run out of feedstock pretty quickly.

I think that until the next big fuel comes along, we are going to enter
an age of "niche" fuel production.

That is okay, as long as we don't get involved in feedstock that might
otherwise be food, ie corn/ethanol production. There are possible
ethical considerations that will crop up in that case.

- Mike KB3EIA -