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Science

Freeing Hydrogen From Glucose 40

Posted by timothy from the schweet dept.
tarawa writes: "This story at CNN reports that researchers have developed a new and easy way to extract hydrogen from a glucose solution that could provide a clean, environmentally safe fuel for our cars in the future." Stay calm, though -- ""We are not talking about spooning glucose into your car to make it go. That is 'Back to the Future' stuff."
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Freeing Hydrogen From Glucose More

Freeing Hydrogen From Glucose

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  • Wait... (Score:2, Funny)

    by Dr. Bent ( 533421 )
    I thought sugar in your gas tank was a BAD thing...
  • Fixed ratio of H2 released to CO2 released.

    I suppose no one, or thing, would have been interested in consuming the Glucose before it completely degraded... (cows, cats, ants.... uhuh)
  • The source for glucose is..?

    • PEOPLE! (Score:3, Funny)

      by Thoth Ptolemy ( 110353 )
      Accelerant glucose is made of people!
      IT'S MADE OF POOOOEEEEPLLLLEE!!!
    • Plant material.

      That's the beauty of it, we can get H2 from a easily renewable resource. Apparently, the only waste product that is even marginally dangerous is CO2, which will be used up by all the extra plants we would have growing for fuel. It fits right into the earth's carbon cycle.

      One really good way they could do it would be to use food waste; apple cores, orange peels, etc. These all contain lots of cellulose, which is just a polymer of glucose. Cellulose can be purified from these sources, and it can't be too hard to do, they sell ultrapure cellulose pretty cheap.

      The glucose can be liberated enzymatically (or possible otherwise...chemists?) and then used to make H2

  • experimenting with fuel cells powered by hydrogen which produces a lot of energy and whose only by-product is water.

    Can't beat CNN for a detailed scientific description of new technologies. Has anyone found a paper or press release or anything?

    • If you look at the bottom of the article there are a number of associated links listed. One of them is Nature [nature.com], a British science journal. If you do a search at Nature (I used 'glucose' and 'hydrogen' as keywords) a number of relavent articles will show up. Unless you are willing to pay for a subscription, then you are likely to need to pass by your local university library to read them, as the results are just abstracts.
    • If you don't have a subscription to Nature, the absract is here [nih.gov] If the link is busted, go to NCBI [nih.gov] and search for "Dumesic glucose" under Pubmed.
  • How much heat do you get from C6H12O6 + 6O => 12H + 6CO2? And what is the molecular mass of C6H12O6?

    • Re:Questions for the chemists (Score:4, Informative)

      by GMontag451 ( 230904 ) on Friday August 30, 2002 @03:06AM (#4168531) Homepage
      How much heat do you get from C6H12O6 + 6O => 12H + 6CO2? And what is the molecular mass of C6H12O6?

      First of all you wouldn't get 12H, you'd get 6H2. I don't know about the heat, but the molecular mass is pretty easy to figure out. 6C = 6*12. 12H = 12*1. 6O = 6*16. That makes 72+12+96=180. What I want to know is how they are keeping the H2 from combining with the O2 at those temperatures.

      • What I want to know is how they are keeping the H2 from combining with the O2 at those temperatures.
        They don't, because there is no O2; they start with a water solution of glucose. The reaction would appear to go something like this:

        C6H12O6 + 6 H2O -> 6 CO2 + 12 H2

    • According to my only readily available source ('Energy: a Guidebook' by Janet Ramage) the combustion of hydrogen releases 37 kWh/kg. That's more than twice the heat released from methane.

  • Two inaccuracies in the story (Score:3, Informative)

    by GMontag451 ( 230904 ) on Friday August 30, 2002 @03:19AM (#4168547) Homepage
    He says the process does not produce extra carbon dioxide, as this would have been released back into the air anyway through biodegradation of the plants.

    This statement, which I suppose is technically true, is absolutely ludacris. It would be like saying that burning down the rainforest wouldn't produce any extra carbon dioxide for the same reason! If this process becomes widespread, even though it won't technically produce any more carbon dioxide than would have been produced, it will produce it a hell of a lot faster and there will be higher concentrations of it in the atmosphere.

    At present in the laboratory bench process, hydrogen constitutes about half of the product from a catalyzed glucose solution. But with further refining of the sugar solution the percentage rises.

    The percentage cannot rise above 50%. The reaction is C6H12O6 (glucose) + 6O2 -> 6H2 + 6CO2. And that's only 50% by volume. By mass its only 4.3% H2 and 95.7% CO2.

    • Re:Two inaccuracies in the story (Score:5, Interesting)

      by famebait ( 450028 ) on Friday August 30, 2002 @03:56AM (#4168600)
      This statement, which I suppose is technically true, is absolutely ludacris

      Nope, nor is it ludicrous; it is common sense, as long as the fuel is produced from cultivated plants. And the article did say renewable sources.

      It would be like saying that burning down the rainforest wouldn't produce any extra carbon dioxide

      No, that would contribute extra CO2 until the areas grew back with an equivalent amount of biomass. After that the balance would be restored (as long as we're talking only about CO2), but it would take a long time and there's no guarantee it would happen at all. Rainforests are not generally considerd a renewable resource in practice. Normal farmland is usually renewed all the time.

      it will produce it a hell of a lot faster and there will be higher concentrations of it in the atmosphere.

      The speed of the carbon cycle is irrelevant, the important part is how much carbon is bound up in plants and elsewhere and thus kept out of the atmosphere at any given time. I can't see how this fuel scheme would be different from any other cultivation on the same land in that respect.

      Another question is whether it is ethical or viable in the long term to use land for growing fuel in stead of food, but that is a very different matter.

      • Another question is whether it is ethical or viable in the long term to use land for growing fuel in stead of food, but that is a very different matter.

        Of course it is ethical. Right now we produce far more than enough food to feed the entire world, though perhaps not healthily since we didn't actually evolve to eat all these carbohydrates.

        The problem is one of distribution, which could actually be aided by a source of cheap, non-polluting fuel. It won't be, because the problem is one of ethics, not logistics; There's more than enough money lying around to feed all those hungry people, too (IE, get the food to them) but it won't happen because of selfishness.

        Note that I too am selfish and do not spend my money on feeding Somalian children, but then again I'm worried about making rent right now, so I have a valid excuse. Next time I have a job, I won't have one, but I still won't feed the starving children. Boy, am I an asshole.

        As for viable, you have to look at what nutrients these particular plants remove from the soil, and what it costs/what damage it does to put them back in. This could easily spill over into "ethical" as well, I suppose, given that agriculture changes global weather patterns if carried out on a wide enough scale. But if it catches on perhaps instead of paying farmers to grow nothing we can pay them to grow hydrogen crops.

        • Rofl, don't talk ethics about growing food vs. growing energy. Look at the ethics conundrum involved in buying Oil from Saudia Arabia. A majority of the 9-11 hijackers were from Saudia Arabia...do you think it's ethical to do business with people who support active terrorism against the U.S and its allies?

          When we have to debate eating corn vs. using corn to power my car, I will beat my gun into a ploughshare. I will, really.

          Salis
        • Right now we produce far more than enough food to feed the entire world...

          actually, a very large part of the food we produce is used to feed other food -- cattle. americans eat so much beef (and a lot of chicken too) which is, from a food efficiency standpoint, a bad thing.

          this is actually one of the reasons i'm vegetarian -- the way i see it, food raised to feed animals is mostly wasted since the animals just turn most of that food into shit.

          ...though perhaps not healthily since we didn't actually evolve to eat all these carbohydrates.

          now that's just silly, there is more to vegetable matter than carbohydrates. consider beans (high in protine) or legumes such as peanuts (high in oil) etc. just because we grow lots of corn (to feed cattle, who are ruminids, evolved to eat grass and therefore, when corn-fed, need large quantities of antibiotics to disrupt the fermentation process which would otherwise result in a slimy glop that prevents the expulsion of the fermentation gasses (CO2) and would cause the rumin organ to expand to the point of collapsing the cattle's lungs, killing the animal) doesn't mean we can't grow soy, wheat, squash, fruits, etc. on that land.

          the real problem is the subsidies that mean growing corn (with tons of nitrogen fertilizer which results in run-off and destroys aquatic habitat) for a non-human market is more profitable than growing human food.

          there's more but why bother. tell me otherwise and i'll continue
        • Of course it is ethical. Right now we produce far more than enough food to feed the entire world, though perhaps not healthily since we didn't actually evolve to eat all these carbohydrates.

          More importantly, is growing plants the most efficient way to convert sunlight to usable energy? Which gets you more useable energy growing corn on 1 acre of land for 10 years? Or, 1 acre of photovoltaics for 10 years? Which one results in more energy net energy inputs?

          Then you have to consider which process results in more hydrogen for mobile applications. Photovoltaics & electrolysis of water. Or, corn plus the process described in the article.

          Dastardly
    • Got a chance to read the article (the real one, not the CNN article)

      The CO2 production/recovery by plants issue is well addressed in the first reply.

      As for the 50% figure....

      Glucose is C6O6H14, not H12. Sugars are CnOnH(2n+2) in these conditions. The H12 refers to the ring structure. They're saying they get almost, but not quite, 100% of the H2 recovered if they use glucose.

      On other stuff in the letter (it's not a full paper)....

      The guy even proposes a complete system, with their reactor connected to a fuel cell working at 50% efficiency (Engineers.....Is that realistic?). He states that based on the rate of H2 formation that they got at conditions for optimal efficiency, you could get 1kW of electrical power per liter reactor volume. The reactor would use bio waste (wood, grain chaff, etc).

      He says the main drawback is the use of Pt as a catalyst; he says there may be better and/or cheaper ones.

      The thing that really got me was the first line:

      We consider production of hydrogen by low-temperature reforming (at 500K)

      Since when is 227 degrees C a low temperature?

    • Um, I think he's comparing the use of carbon that's recently been in the atmosphere (plant based) versus adding carbon that's been underground for a long time (oil based).

      Also, this CO2 would seem to be pretty easily isolated and clean, for use in stuff like carbonating water, adding to greenhouses maybe, or just storing in calcium carbonate somewhere to keep it out of the atmosphere.

      Thinking about that middle idea, I kinda like the idea of pumping the CO2 back into greenhouses used to grow the glucose in, so we're recycling the carbon and outputting the H2. Anybody know if we can conveniently extract glucose from algae? From kelp, maybe?

      Maybe I'm missing something, but this sounds distinctly like a Good Thing to me if it can be done economically.
  • Stay calm, though -- ""We are not talking about spooning glucose into your car to make it go.

    Uh.. So putting sugar in my gas tank was a bad idea? I knew I should have read more than just the title! ;-)

  • Crap, and here I thought we were going to get a Mr. Fusion Home Energy Converter [entermyworld.com] to slap on our Deloreans.
  • We already have glucose powered vehicles. They are called "horse and buggy".
  • Man... I sooooo need my Mr. Fusion. Plutonium is getting soooo hard to get now that I can't even travel back in time to when it was easy to get!

  • Maybe it was because the American flag icon [slashdot.org] was adjacent to the headline, but I read "Freeing Americans From Glucose" and thought that it was about time someone did just that. Maybe my health insurance premium would go down then...

  • Hydrogen powered fuel cells will do more than operate cars. In fact, cars will probably be the last application of hydrogen fuel cells, partly because carrying a tank of compressed hydrogen around in your car is rather cumbersome. But, imagine all of the factories, manufacturers, refineries, power plants, etc that exist in the U.S? Refineries alone consume something like 5% of the US Oil consumption.

    Now instead of buying that oil from Saudia Arabia, wouldn't it be so much better to grow it in the MidWest? The US already produces more corn than it can consume and so finding new ways to use it to supplement our energy consumption is TRULY amazing.

    Once the effeciency of the involved catalysts increases and the large-scale process is designed you can say BYE BYE to our growing dependency on the MidEast Arab countries and their autocratic governments. The only resource they have is Oil. The only reason why their government is stable is Oil. The only reason why the United States tolerates their lack of civil rights is Oil.

    Bye Bye Oil, Bye Bye Tyranny!

    Say Hello to Mr. & Mrs. Smith of Indiana who farm 1500 acres of corn.

    Which would you prefer to do business with?

    Salis

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