Nuke reactors & Sci Am on hydrogen economy

[Nords]

The "Equities & Terrorists" thread (http://early-retirement.org/cgi-bin..._board;action=display;num=1087657588;start=60) mentions a hydrogen economy and nuclear technology. Allow me to ramble for a few paragraphs.

The May 2004 Scientific American (http://www.sciam.com/article.cfm?chanID=sa006&colID=1&articleID=000600B1-1A4E-1085-94F483414B7F0000) looks at the hydrogen economy and concludes that it's tempting, but other technologies are closer to fiscal reality. Apparently the most economic process of producing hydrogen (from methanol or natural gas) also produces a tremendous amount of CO2-- a big greenhouse gas problem. The author concludes that fuel cells will start showing up in houses, cell phones, survival gear, & laptop computers... but that diesel and/or electric cars are much closer to economic success.

Hydrolysis is a BIG loser. Personally the logistics challenges of generating, transporting, storing, dispensing, & using hydrogen scare the heck outta me. Today submarines use oxygen generators that electrolyze pure water into H2 & O2. The O2 is stored in 3000-psi tanks and the H2 is vented overboard as soon as it can be disposed of. Submarines also use nuclear reactors and many varieties of highly explosive ordnance. I never had an emergency with the explosives or the reactor (other than "minor inconveniences") but I've had several emergencies with oxygen generators. Even under normal operation they're a PITA requiring extensive labor-intensive monitoring and expensive maintenance. British submariners enclose their generators in explosion-proof steel cases, and there's a reason that we all refer to them as "bombs". Even the manufacturer (http://www.treadwellcorp.com/index.html) has seen the light and is moving from electrolysis to proton-exchange membranes.

The new reactor technology that TH mentions is a pebble-bed reactor. (http://web.mit.edu/pebble-bed/) I believe it uses regular or enriched uranium and the heat is transferred to helium, which isn't easily made radioactive. The advantage of the pebble-bed design is that it'll shut itself down if it loses power or flow, something that's much more problematic (yet achievable!) in a pressurized-water reactor.

Fifty years of material science has taught us nukes a lot, and today's reactor components have radiation levels that are literally orders of magnitude lower than the bad old days. Practices that were routine to me as a "young nuke" would be horrific stone-age implements in today's Navy. So disposing of tomorrow's old fuel pebbles will be "no big deal" as long as they're accounted for. When the civilian industry can economically compete with cheap coal/oil/natural gas, the pebble-bed design will move out of the lab and become an industry standard.

If you've read this far and you're still awake, thanks for indulging me. My spouse really hates having to hold up her end of the conversation on these topics, and my kid still has trouble pronouncing "self-saturable burnable poisons"...

 

[wabmester]

I still think the solution is right under our noses. Photosynthesis: CO2 + H2O + photons -> O2 + (CH)*. We get rid of the CO2 problem, produce something we already know how to burn for fuel, and get a fresh scent to boot.

 

[haha]

If you've read this far and you're still awake, thanks for indulging me.  My spouse really hates having to hold up her end of the conversation on these topics, and my kid still has trouble pronouncing "self-saturable burnable poisons"...

LOL. I have the same problem, finding someone who wants to discuss almost any topic rigorously.

I'll get the Scientific American article. I am interested in nuclear power as an investment theme. I feel that our current strategy of trying to secure MidEast oil is a human and economic loser. We need to move quickly to more nuclear generation of electricity, and probably an economy more powered by kilowatts than IC engines.

As to companies that will be able to make money off this, it isn't very clear yet to me. GE, the French reactor builder Areva, who else?

Thanks for the information dense post.

Mikey

 

[unclemick]

EXC - my lonely atomic ute among my hobby stocks - bought way back when it was yielding around 8% as Commonwealth ED. and 'not recommended' by Utility Forecaster as atomic power in general was a no no.

The pebble reactor on PBS long ago was German, used He and the cermic balls withstood shutting off the gas.

Breeder reactor technology has legal/policatal limitations in the US.

And I haven't heard much from past proponents - France and Japan.

I hear noises about expanding/adding to current atomic plants/sites as the best way to go - surfacing periodically.

 

[ak4195]

Toshiba i believe is proposing to the state of Alaska to build a small self contained nuclear reactor(approx $20 million),in the town of Galena. Being far from the state road system,the diesel is barged up the yukon river,where,like most small alaskan towns the power is generated by large diesel generators.As you might expect its rather pricey,so the town was searching for alternatives,and apparantley the corporation approached the city with there solution.I dont remember the specs,but this tiny reactor was more than enough for the town and infrustructure in the area.While this doesnt mean much for say L.A or any large city,for a small town,or perhaps an industrial concern,its a big deal--ak4195

 

[John Galt]

I wish I had the exact numbers on this but you will get
the idea. Downstream from our house about 10 miles
is a hydroelectric dam. Been there forever. Upstream
about 10 miles is a modern nuke plant. I read once that
the nuke plant can produce the same power in about 15
minutes as the dam does in a year. Something like that.

John Galt

 

[BigMoneyJim]

John Galt, I think I'd rather have the nuke plant downstream, just to be absolutely sure.

 

[charlie]

Nords,

Thanks for the Scientific American link. I used to take
that as a teenager and it helped led me into an
engineering career. I may subscribe again.

Re the "hydrogen economy" issue this is what
makes sense to me:

Design a small, highly automated, "fail-safe" nuke
to generate electricity for hydrolysis of water to
produce hydrogen and oxygen. Use the hydrogen
as a fuel source to power conventional electric
generators and vent the oxygen or compress it for
commercial use. Build a hydrogen fuel cell factory nearby. I have no idea if the numbers would support
this concept, but it is fun thinking about it.

The environmental benefits are enormous. No air
pollution by the power plant and no emissions except water vapor by autos, trucks, etc.

Even the tree-huggers could/should buy into this if
can do the right job on the nuke design.

This is something that could be phased in over time.
If we could design a highly efficient battery with quick
recharge time, we could even eliminate fuel cells
as an automotive power source eventually.

I love talking about this stuff.

Cheers,

Charlie

 

[unclemick]

Fun to talk about - I agree. I think back in the sixties The American Chemical Society mag did a long article about the coming hydrogen economy. Maybe the technology has progressed to get the numbers more workable.

As an investor - utes to me still look the safest bet, The hardeware makers seem to be 'big' corps with nuclear as a small part of their business. As for the construction engineering firms - well I'm open to suggestion. They seem to have some pretty good up/down cycles. I owned Stone and Webster many years ago with 'less than good results'.

heh. heh ?International firms?

 

[Nords]

Hydrolysis is more expensive than catalysis

It's true that the hydrogen economy has no combustion products coming out of tailpipes, but making the hydrogen (by current catalysis technology) causes more pollution than refining & burning gasoline.

Using "clean" nuclear power for clean hydrogen sounds great, but it's easier/cheaper to make the H2 from natural gas or methane. Unfortunately then you have that greenhouse gas problem again and it becomes a regulatory (expensive) issue.

The thermodynamics of hydrolysis is attractive, but engineering to reality is complex. I don't know how large-scale oxygen producers make their gas, but I doubt it's hydrolysis. Navy systems use a dozen six- or seven-foot-tall cells per generator operating at 3000 PSI. Each cell is filled with water and lots of sodium hydroxide, which improves the reaction but basically puts a couple hundred gallons of lye behind the explosion potential. Add in expensive solid-state electronic controls, high-pressure (oxygen-clean!) valves, and plenty of rubber O-rings. Any minor problems cost thousands (or more) to fix. From personal experience, one blown seal fills a room with a cloud of caustic gas faster than you can evacuate. Gimme good ol' fashioned fires & flooding anytime.

It's much cheaper to hook that nuke plant into the electrical grid. Then it's much simpler to put batteries in cars. And although it's not as cheap as gas (yet), it's much less pollution than current hydrogen-catalysis technology. I wouldn't try to cross Death Valley in an electric vehicle, and I don't want to get on a four-lane highway driving a modified golf cart that can't hold a longboard, but I'd happily drive an electric vehicle around Oahu if it's cheaper than the fuel-burning junkers parked in my garage.

Who knows, in a couple years when they're on the secondary market I may be a Prius owner...

 

[guest]

Read an online article sometime ago about successful attempts to "store" hydrogen in a compund not unlike ordinary table salt. To "fill up" your vehicle you'd go to the grocery store and pick up a bag of it. If you drop it or get into a crash all you've got is a fine non-explosive granular material on the road. Just wash it away.

I don't see environmentalists ever allowing another nuke plant (of any design) or dam to ever be built in the USA again.

 

[unclemick]

Air Reduction and Air products have big plants near the NASA facility where I used to work. Powered in essence by natural gas or mostly natural gas derived electricity. Not an environmentalist's dream - lots of visible smoke/stuff coming out the stacks.

But the Prius offers hope - progress is being made made.

And isn't the Air Force funding an active flow giant battery pilot demo - I think it's for lots of 'pure' un-interrupted computing but a lot of utilities with 'peaking problems' are following it.

The next step beyond Prius is mastering the home and work plug charge up. Our in plant Cushmans during my working years didn't exactly charge with blazing speed.

The long wait for electric utes to gain growth status requires a 'new' big source of demand.

In the early days - steam, electric, gasoline, and even a compressed gas car were duking it out until the internal combustion engine we have won out. May take a for atomic and we may not recognize the form it takes. Should be interesting.

 

[charlie]

Nords,

Do you have any idea of the BTUs available per
unit of water if split into hydrogen and oxygen?
This is a serious question. I don't know how to
go about the calculationl

Regards,

Charlie

 

[Nords]

Ouch, my brain hurts.  Guess I had that coming...

Degrees in chemistry & nuclear engineering combined with the obstinacy formed by "%^$, I used to know how to do this!"

I've been separated from my Navy notes, but this website squares with my memory: "In order for 1,000 standard cubic feet of hydrogen to be produced, 150 kilowatt hours would need to be expended and seven gallons of water would need to be electrolyzed."
http://web1.caryacademy.org/chemist...ebSites/hydrogen/how_hydrogen_is_obtained.htm

That also matches my desktop reference, and 1 BTU = 1055 J = 1055 W*sec (see Note 1 below) so with that and a few conversion factors we get

150 KWh/7 gallons of water *1 BTU/1055Wsec * 3600 sec/h * 1000 W/KW = 73,121 BTU/gal.

But that's nowhere near the subsequent amount of work involved in storage and in keeping the H2 & O2 separated from each other.

(Note 1: So that's why I've lugged those old textbooks around for two decades!)

OK, that was fun, but now it's time to ease these highly-trained brains gently through the back door so that I can devote the rest of my day to weeding & composting...

 

[charlie]

Thanks, Nords. I knew you had it in you.

As for storage and keeping the H2 and O2
separate, why not just burn the hydrogen
as it is produced to drive a conventional
electric generation plant? You could just
vent the oxygen if you didn't want to
compress it for industrial use.

Please forgive me if these are dumb questions.
I am an EE who almost failed thermo. I thought
about going for a physics degree while in high school,
but the thought of taking P-chem in 2nd year at
Rice terrified me and I morphed into EE by default.

Cheers,

Charlie l

 

[cute fuzzy bunny]

I thought
about going for a physics degree while in high school,
but the thought of taking P-chem in 2nd year at
Rice terrified me and I morphed into EE by default.

I used to bring donuts to physics class and eat them until the teacher threw me out. I think I only attended 3 full classes, but still somehow got a C+. Go figure.

 

[charlie]

I found a source that says 1 cu. ft. of H2 gas is
equivalent to about 3400 BTU.

Nord's source says it takes 150 KWH to produce
1000 cu. ft of hydrogen gas. This equates to
6.67 cu ft per KWH input.

I also found a source that says 1 BTU = .000293 KWH

Do the math and we get 22678 BTU out per KWH in.

22678 BTU is equivalent to 6.64 KWH . Thus we
get the equivalent of 6.64 KWH output for 1 KWH
input.

Of course this assume perfect efficiency of conversion
which is impossible. Nevertheless, unless I broke my
slide rule, the numbers are interesting .... ?

Cheers,

Charlie

 

[Nords]

They're not dumb questions but.

Chuck,

The biggest challenge of electrolysis is keeping the two gases separated until you're ready to do something with them. Burning off the H2 works fine but combustion requires oxygen and produces water, which is what we started with. As you say, the process isn't efficient (even 20-25% is a thermodynamic Holy Grail) so you'd be chewing through electricity at a frantic pace to convert pure water into extremely pure water. It reminds me of many government programs.

They're not dumb questions. We used to have hours of entertainment in the engineering spaces with these thought projects. (Hey, we were nukes. It was either that or study reactor plant manuals.) Although at my college, the EE students were gods among mortals. Somehow they also had the best stereo systems and in-room refrigerators!

I thought Pchem was a lot easier than organic chemistry. But my clearest college memory is of my thermo prof who ran a side business developing video training products for energy companies. He used to test his curriculum out on us guinea pigs, er, undergraduates, on the college's time. We'd happily critique it to death during class to distract him from quizzes & homework. Sometimes we'd even help with the fixes for extra credit. And then he'd turn around and sell "our" product for thousands of dollars to dozens of companies for years after the class was over. That was my first inkling of how academia could be heterodyned to ER. And he was probably having too much fun to ER...

 

[unclemick]

Eggers, Gregory, Halsey and Rabinovich - those of us who survived the first three quarters of Pchem - editing handouts and solving the problems - got to buy the new textbook for the fourth quarter -AT the publishers price.

Burns my butt to this day. Lets go back to atomic power or something.

 

[charlie]

Well pooh! I thought we had a potential perpetual
motion machine almost going. If the process could
achieve an overall efficiency of 15% or greater, we
would have it made.

If we could get the efficiency high enough, we would
not need the nuke. Just feedback enough power
to keep the process rolling.

I think you are probably right about the nukes ....
just hitch them directly to the grid and concentrate
on battery technology breakthrough.

Cheers,

Charlie

 

[charlie]

A company called Proton makes hydrogen generators
for the semi-conductor industry. They make generators
that produce about 100 cu. ft per 17 KWH input.
This is pretty close to the 1000 cu ft per 150 KWH
noted by Nords. The link is provided below:

http://www.protonenergy.com/index.php/html/gasproducts/refuelers/index.htm

Does anybody have any idea what is the overall
efficiency of a natural gas fired electrical plant?
Like X cu. ft/hr to produce Y KWH?

OK, I know this is boring to most of you but please
be patient.

Thanks,

Charlie

 

[charlie]

Ok, I found a source that says conventional gas
fired steam generators max out at about 37%
efficiency while gas turbine plants can achieve
about 50% efficiency.

So Nords, what am missing? In my previous post
I calculated that for 100% conversion efficiency,
we could get 6.64 KWH output per KWH input.

At 50% efficiency, we still get 3.32 KWH output
per KWH input.

"All we have to do" is scale up the Proton generator,
tap into the grid to "prime the pump" (so to speak)
and achieve lift off into the hydrogen economy.

Cheers,

Charlie

 

[charlie]

Well, I screwed up the calculation. As it turns out,
the heat equivalent of H2 is about 297 BTU per cu. ft.,
not 3400 BTU as previously reported. Thus the
conversion yields only 0.58 KWH output per KWH in.

Back to the drawing board.

@&!&#

Charlie

 

[Whakamole]

More importantly, how does one invest in these technologies?

I've investigated wind which on the plus side is cost-effective. But it requires a lot of land, and I've got to think that if something more practical comes up, that will become the predominant source of power generation.

 

[unclemick]

I still get the touts in the mailbox - even after eleven years of ER. Mostly biotech, IT, but enegy has been picking up lately. You know the ones - buy this new mini-stock because it will made you rich while they 'revoluntionize' this or that. Or course the touter has probably been granted a large block of stock at low or no cost - but heh heh - I don't know that because they never mention 'that' in the flyer.

Seriously - I think utes are still the the safest way to play - even though it's a small part of a larger operation you get divs. The hardware people are probably also large and mutli faceted to control risk - the same with the construction/engineering cats. Maybe some poking around would turn up smaller co's with better risk/reward but I ain't about to bet my ER on Ballard Power or that ilk yet.