avtr01
Harmless
Posts: 19
Registered: 10-4-2004
Location: california, united states
Member Is Offline
Mood: curious i think
|
|
Misc catalysts
Hi all,
I was just reading about all the industrial processes that are used to break down hydrocarbons like ethanol into H2 gas-sort of like a
"cogenerator". I read that you need some sort of fancy schmanzy catalyst that is almost impossible to find. Do any of you geniuses out
there know of any sources for a catalyst that I can make a cogenerator out of?
Thanks
|
|
|
unionised
International Hazard
Posts: 5126
Registered: 1-11-2003
Location: UK
Member Is Offline
Mood: No Mood
|
|
Pardon?
|
|
|
axehandle
Free Radical
Posts: 1065
Registered: 30-12-2003
Location: Sweden
Member Is Offline
Mood: horny
|
|
I'm not sure I understand the question. You want a catalyst that breaks down a fuel like CH3CH2OH into H2????
Why? If the CH3CH2OH comes from grown plants, is combusted, the exhausts spread into the atmosphere..... you don't NEED to break it down.
It's a cyclic product. It leaves the CO2 and H2O balance unchanged, as opposed to where you're burning products made from oil.
Please rephrase the question.
My PGP key, Fingerprint 5D96 E09E 365D 1867 2DF5 C2FE 4269 9C19 E079 CD35
\"Verbing nouns weirds the language!\"
|
|
|
Geomancer
Hazard to Others
Posts: 228
Registered: 21-12-2003
Member Is Offline
Mood: No Mood
|
|
Are you talking about obtaining a hydrogen-rich feed gas from fuels like ethanol? This is a popular field these days. Search under "steam
reforming" and "water gas shift". I don't know of a commercial source for catalysts, and, you're right about some of them
being fancy. Papers detailing preparation of some reforming catalysts are available online, though.
|
|
|
avtr01
Harmless
Posts: 19
Registered: 10-4-2004
Location: california, united states
Member Is Offline
Mood: curious i think
|
|
sorry for the confusion. I didn't mean cogenerator, I meant reformer. Thanks for catching the slip up. What I was referring to was the process
where an alcohol or any hydrogen rich fuel is vaporized, mixed with steam, passed over a catalyst and turned into H2 gas. It just struck me as
strange that the only catalysts that are used are unavailable to anybody that wants to make one from scratch. Could I try and find a catalytic
converter from a junk yard to use? Supposedly it has palladium plated on the ceramic balls?
Thanks
|
|
|
Hermes_Trismegistus
National Hazard
Posts: 602
Registered: 27-11-2003
Location: Greece, Ancient
Member Is Offline
Mood: conformation:ga
|
|
Probably just too specialized.
I've heard of this particular field, but even let us suppose there is a hundred people a year coming into this new field and each one wants to
make their own individual experimental set up's..............you could still probably hold all the catalyst being used today.... in a bag.... in
your left hand........ (with enough room left over for a chocolate shake and a bean burrito)
with that kind of volume and the fact most research scientists make peanuts, I'm not suprised there aren't many/any large commercial
enterprises involved in making these substances readily available. If there are, I bet they don't waste alot of time/money on advertising. I
betcha it's just a word of mouth kinda thing.
I can't see why someone at the top level wouldn't just prepare their own, (or get a grad/postdoc student/slave to do it for them)
Solution.....find someone currently involved in this kind of research and milk them for info/sources.
Arguing on the internet is like running in the special olympics; even if you win: you\'re still retarded.
|
|
|
avtr01
Harmless
Posts: 19
Registered: 10-4-2004
Location: california, united states
Member Is Offline
Mood: curious i think
|
|
Not to mention that the oil companies don't like new kinds of fuel options
It seems that every time some new way of coming a better way to control pollution comes up, they "buy" the knowledge and sell it for a much
higher price than it is worth (example: solar power owned by BP, shell, etc...)
but seriously, why are the catalysts so expensive? It seems like the only catalysts that are used to break down hydrocarbons cost >$10 gram
Thanks
|
|
|
Magpie
lab constructor
Posts: 5939
Registered: 1-11-2003
Location: USA
Member Is Offline
Mood: Chemistry: the subtle science.
|
|
catalyst costs
Not all catalysts are expensive. But for your application probably so.
Catalysts tend to be specific to certain reactions. The catalysts used in auto exhaust converters are made from palladium I believe. Palladium is
expensive because it is rare like platinum and gold. If you can find a cheaper substitute for an expensive catalyst you will have found yourself a
patent and possibly a career.
|
|
|
avtr01
Harmless
Posts: 19
Registered: 10-4-2004
Location: california, united states
Member Is Offline
Mood: curious i think
|
|
How are catalysts discovered? Do chemical engineers use computer programs or just trial and error? Does anyone have any good sites that visually show
what a catalyst does to speed up reaction time?
Thanks
|
|
|
Organikum
resurrected
Posts: 2337
Registered: 12-10-2002
Location: Europe
Member Is Offline
Mood: frustrated
|
|
Trial and error. Sabatier for example a hundredfifty years ago found out about catalytic effects of some metals on certain organic compounds in the
gasphase and started to experiment - this was basically the beginning of all this.
For your questions on ethylalcohol you should download the file "Ethanol_Reactions.pdf" from the ftp so it is up again - you will find all
your questions answered there.
|
|
|
axehandle
Free Radical
Posts: 1065
Registered: 30-12-2003
Location: Sweden
Member Is Offline
Mood: horny
|
|
nitpicking
| Quote: |
Catalysts tend to be specific to certain reactions. The catalysts used in auto exhaust converters are made from palladium I believe. Palladium is
expensive because it is rare like platinum and gold. If you can find a cheaper substitute for an expensive catalyst you will have found yourself a
patent and possibly a career.
|
Close --- it's actually typically a 10/90 Rh/Pt alloy.  : http://en.wikipedia.org/wiki/Rhodium
My PGP key, Fingerprint 5D96 E09E 365D 1867 2DF5 C2FE 4269 9C19 E079 CD35
\"Verbing nouns weirds the language!\"
|
|
|
avtr01
Harmless
Posts: 19
Registered: 10-4-2004
Location: california, united states
Member Is Offline
Mood: curious i think
|
|
I am really eager to start reading stuff from the ftp site but I thought that you can only download stuff if you upload it. Unfortunately I
don't have anything to upload 
|
|
|
Geomancer
Hazard to Others
Posts: 228
Registered: 21-12-2003
Member Is Offline
Mood: No Mood
|
|
ArcheoZeppelin?
So I just get done writing a nice big treatise, I go and check to see why the BBCode isn't working, and BAM!, no more treatise. Oh well...
When I was looking for info regarding the original question, I stumbled upon a site, which I can no longer find, describing the possibility for
pre-industrial societies with little access to metal having produced hydrogen in suffecient quantity to allow lighter than air flight. I don't
remember many of the details, so what follows is my modification of the original idea. In particular, the original author produced H2+COx+N2, and
proposed separating the result by diffusion; I propose a different way of obtaining pure product.
The hydrogen producers would build a linear furnace out of insulating firebrick, with a bellows at one end. Within this furnace, they would place
a tube of dense firebrick, closed at the end farthest from the bellows, and extending out of the furnace at the other. Within the closed end of the
pipe, a bowl of water would be placed. They would charge the remainder of the pipe with charcoal. A few holes are made in the pipe just before it
exits the furnace.
The furnace would first be brought up to temperature. The water would boil, and react with the heated charcoal to form a mixture of H2, H2O, and
CO (water gas). Some of the water gas would escape via the holes in the pipe, to be burnt with air from the bellows and supply heat for the operation.
The remainder would be passed over quicklime, partially slaked. The CO would react to form the formate, and residual water also absorbed, leaving a
stream of pure hydrogen.
In the preceding description, I have omitted several points that would improve operating effeciency. Most important, the yield can be almost
doubled if additional steam is introduced after the gas has passed over the charcoal bed. Some catalytic rocks or something may be needed for the
shift reaction to occur reasonably quickly, though. Second, several reaction tubes would be operated in parallel. Some of these tubes would be active,
some being recharged, at any given time. The heat of the furnace would be used to regenerate the quicklime from the inactive tubes.
This technology may appear difficult to motivate. There is certainly no evidence of hydrogen airships being used in the ancient world. However,
consider the fact that the Chinese have used hydrogen reduction firing with water gas for ceramics for two millenia. From here, it is four
"easy" steps to hydrogen flight:
Find a use for the formates that you've noticed occasionally form in kilns. Current uses include tanning and preserving foods. Produce
formate as a coproduct to pottery.
Develop hot air flight. It is conceivable some ancient societies knew this.
Notice that the exhaust of your H2 reduction firings works better than other kiln exhausts for ballooning.
Deduce that the special principle from 3 can be produced more purely, and optimize the technology.
Anyone up for some experimental "archeology"?
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
