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Thread: Hydrogen engines

  1. #31
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    Quote Originally Posted by Swift View Post
    ????

    I don't understand. What further reactions? Are you talking about hydrogen? The only way to make hydrogen a liquid is under pressure or cryogenically.
    Right. The search space for viable fuels is not especially large or complicated...you're not filling up your car with nickel tetracarbonyl or triethylborane. Hydrogen, fairly short chain linear hydrocarbons or the related alcohols, and with some difficulty, perhaps aluminum or one of a handful of other reactive metals. We don't need an AI to tell us that. Computational chemistry might help in optimizing their production, but it's not going to change their basic properties and basic physics tells us they're going to be more expensive if not produced from fossil sources because they're then an energy transport medium instead of an energy source. There's no magic chemistry for getting around that, you have to either drive down energy costs or wait for fossil fuel costs to rise.

    Batteries are another matter, their chemistries can be very complex and contain a variety of exotic substances. And computational chemistry is a significant tool in battery chemistry research, as a trivial Google search shows.

  2. #32
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    And computational chemistry is a significant tool in battery chemistry research, as a trivial Google search shows.
    I saw that and I also saw some chemistry simulators as well but I think some work can be done there to improve them.



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    Quote Originally Posted by Swift View Post
    ????

    I don't understand. What further reactions? Are you talking about hydrogen? The only way to make hydrogen a liquid is under pressure or cryogenically.
    If I remember you are a chemist so I'm not saying anything you are not aware of. Methanol is very storeable and can be manufactured with carbon dioxide and hydrogen.
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    Quote Originally Posted by Copernicus View Post
    If I remember you are a chemist so I'm not saying anything you are not aware of. Methanol is very storeable and can be manufactured with carbon dioxide and hydrogen.
    Yes I'm a chemist and yes there are multiple routes from carbon dioxide to methanol, though the various methods are either energy intensive (so you would need nuclear or very good renewable power sources) or are slow and inefficient. There has been a lot proposed about a methanol economy as a way to deal with climate change (very good wikipedia article, even compares pros and cons of methanol vs. hydrogen).

    But the discussion was about hydrogen, not methanol.
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    Quote Originally Posted by Swift View Post
    Yes I'm a chemist and yes there are multiple routes from carbon dioxide to methanol, though the various methods are either energy intensive (so you would need nuclear or very good renewable power sources) or are slow and inefficient. There has been a lot proposed about a methanol economy as a way to deal with climate change (very good wikipedia article, even compares pros and cons of methanol vs. hydrogen).

    But the discussion was about hydrogen, not methanol.
    I thought since the methanol came from hydrogen, it was still within the discussion. This is one of the things that frustrated me. If nuclear can produce cheap hydrogen and cheap hydrogen can produce cheap methanol try to stop looking for perfect and settle for real good.
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    Quote Originally Posted by Swift View Post
    Yes I'm a chemist and yes there are multiple routes from carbon dioxide to methanol, though the various methods are either energy intensive (so you would need nuclear or very good renewable power sources) or are slow and inefficient. There has been a lot proposed about a methanol economy as a way to deal with climate change (very good wikipedia article, even compares pros and cons of methanol vs. hydrogen).

    But the discussion was about hydrogen, not methanol.
    I thought since the methanol came from hydrogen, it was still within the discussion. This is one of the things that frustrated me. If nuclear can produce cheap hydrogen and cheap hydrogen can produce cheap methanol try to stop looking for perfect and settle for real good.
    The moment an instant lasted forever, we were destined for the leading edge of eternity.

  7. #37
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    Quote Originally Posted by Swift View Post
    Multiple thoughts on this topic.

    First, for both stationary and mobile power, I don't think there is a single magic solution to decreasing emissions (I assume we are talking about carbon dioxide emissions). Nor does there need to be; a multi-pronged approach is the way to do it. And there are multiple current technologies that would decrease emissions that are available now and are being implemented, if we take the effort to do so.

    My wife and I have been driving gasoline-electric hybrid cars since 2003. My current car gets about 50 mpg over the entire year (MPG drops in cold weather). That compares to 24.9 mpg for the US fleet average. So just switching to hybrids could approximately halve our automobile emissions. No new technologies, no new infrastructure required.

    Going to plug-in hybrids and electrics could decrease this more, again, with little or no changes in infrastructure.

    Hydrogen, either as fuel cells or hydrogen combustion is attractive in many ways, but there are many problems; many already covered in-thread: safety concerns, high pressure or cryogenic concerns, fuel cell and/or engine design. Hydrogen embrittlement of steels can be a big problem; tank design is neither cheap nor easy.

    To me, the two biggest obstacles to a hydrogen economy are production and distribution. Currently, the most common way to produce hydrogen is steam reforming, which produces CO2.



    Obviously, that doesn't help CO2 emissions. What you want to do is make it from water, however electrolysis is a very energy intensive process, photoelectrochemical processes are very inefficient and very far from commercialization (I did research on this back in the mid-80s, and not much has changed). One idea is thermal-nuclear, using heat from a nuclear reactor to split the water, but as soon as you say "nuclear", people go running.

    And even if you come up with a good way to generate it, now you're are going to have to install the infrastructure to distribute all over the country.

    Plug-in cars only save CO2 emissions if the electricity source is sufficiently low-carbon. In most of the world this is not true for mains electricity. I recall it is just about favourable here in UK, but in US and Germany it is not.

    A couple of years back I was able to Google the CO2 per MW-h of electricity by country, and find it. Now I cannot, can anyone help with this?

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    Quote Originally Posted by philippeb8 View Post
    Most of computer scientists are interested into:
    - Gaming
    - Web based apps

    But if you bring one of the following subject then they all flee:
    - Physics
    - Biology
    - Chemistry

    So I wouldnít be surprised not all possible chemical reactions were attempted. Itís a O(n^2) complexity problem after all.


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  9. #39
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    Quote Originally Posted by kzb View Post
    Plug-in cars only save CO2 emissions if the electricity source is sufficiently low-carbon. In most of the world this is not true for mains electricity. I recall it is just about favourable here in UK, but in US and Germany it is not.

    A couple of years back I was able to Google the CO2 per MW-h of electricity by country, and find it. Now I cannot, can anyone help with this?
    The UK recently announced that renewables exceeded carbon sources and France uses more nuclear to achieve that. But sadly coal mines are still opening in some countries. Did you know the internet is a major CO2 emitter because it uses so much electricity.? So this post has a footprint too. There is not much hope of early reductions worldwide, as I am sure you realise.
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    Quote Originally Posted by profloater View Post
    The UK recently announced that renewables exceeded carbon sources and France uses more nuclear to achieve that. But sadly coal mines are still opening in some countries. Did you know the internet is a major CO2 emitter because it uses so much electricity.? So this post has a footprint too. There is not much hope of early reductions worldwide, as I am sure you realise.
    Quote Originally Posted by Copernicus View Post
    ... stop looking for perfect and settle for real good.
    As I mentioned back in post 17, I take Copernicus' view on this. Even emitting less CO2 will in the long run be helpful. I'm a much bigger proponent of many, small, and currently achievable incremental improvements, rather than waiting on the magic technology that will solve everything.

    Better to light a single LED bulb than to curse the darkness of a completely CO2 free economy.
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    Quote Originally Posted by profloater View Post
    But sadly coal mines are still opening in some countries. Did you know the internet is a major CO2 emitter because it uses so much electricity.? So this post has a footprint too. There is not much hope of early reductions worldwide, as I am sure you realise.
    On the other hand, the Internet enables people to have meetings with driving or getting on a plane. And allows people to cooperate on developing new, more efficient technologies. So it may be a win, overall.

  12. #42
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    Quote Originally Posted by Strange View Post
    On the other hand, the Internet enables people to have meetings with driving or getting on a plane. And allows people to cooperate on developing new, more efficient technologies. So it may be a win, overall.
    Indeed. I could not run my business at all without it. Whether that does good may need a different perspective.
    I do think Hydrogen is part of the technology of solution.
    sicut vis videre esto
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    What about a giant electrolysis lab on the Moon, fuelled by solar power?

    It might be cheaper to build such a lab and carry the hydrogen back and forth in the long run.


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    Quote Originally Posted by philippeb8 View Post
    What about a giant electrolysis lab on the Moon, fuelled by solar power?

    It might be cheaper to build such a lab and carry the hydrogen back and forth in the long run.
    I doubt it very much.

    How much would it cost (money and energy) to construct such a facility?
    Where is the water going to come from?
    How much more efficient than doing it on Earth would it be?
    How much energy would it require to transport the fuel back down to Earth (and take the fuel carriers back to the moon)?
    What proportion of the country's energy could it supply?

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    Quote Originally Posted by Strange View Post
    I doubt it very much.

    How much would it cost (money and energy) to construct such a facility?
    Where is the water going to come from?
    How much more efficient than doing it on Earth would it be?
    How much energy would it require to transport the fuel back down to Earth (and take the fuel carriers back to the moon)?
    What proportion of the country's energy could it supply?
    Itís market analysis now... but letís keep in mind hydrogen is lighter than petroleum so it could feed an engine for a longer period of time for the same volume of fuel.

    Also since itís profitable and risk-free (after a proper market analysis) then Iím sure venture capitalists will jump on the occasion to invest.


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    Quote Originally Posted by philippeb8 View Post
    What about a giant electrolysis lab on the Moon, fuelled by solar power?

    It might be cheaper to build such a lab and carry the hydrogen back and forth in the long run.
    Depending on how much water is found, it could be useful for rockets launched from the moon, or perhaps in space use. If you’re suggesting bringing it back to earth, that would never be economic and would be wasting a rare and precious lunar resource.

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    Quote Originally Posted by Van Rijn View Post
    Depending on how much water is found, it could be useful for rockets launched from the moon, or perhaps in space use. If youíre suggesting bringing it back to earth, that would never be economic and would be wasting a rare and precious lunar resource.
    Over time the cost of travelling to the Moon would be more affordable.


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    Quote Originally Posted by philippeb8 View Post
    What about a giant electrolysis lab on the Moon, fuelled by solar power?

    It might be cheaper to build such a lab and carry the hydrogen back and forth in the long run.


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    That's a terrible idea. Depending on location on the Moon and what data you believe, hydrogen is rare to extremely rare on the Moon, and any lunar operation will need as much as they can get for their own uses. The Earth however, last I checked, has a majority of its surface covered by a hydrogen containing substance. Why the heck would you transport hydrogen from the Moon to the Earth? Talk about carrying coals to Newcastle.
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  19. #49
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    Quote Originally Posted by Strange View Post
    On the other hand, the Internet enables people to have meetings with driving or getting on a plane. And allows people to cooperate on developing new, more efficient technologies. So it may be a win, overall.
    Theoretically thatís true. But in the real world, has business travel decreased in line with the spread of the Internet. It might have, but Iím skeptical.


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    Quote Originally Posted by Swift View Post
    That's a terrible idea. Depending on location on the Moon and what data you believe, hydrogen is rare to extremely rare on the Moon, and any lunar operation will need as much as they can get for their own uses. The Earth however, last I checked, has a majority of its surface covered by a hydrogen containing substance. Why the heck would you transport hydrogen from the Moon to the Earth? Talk about carrying coals to Newcastle.
    According to a similar article, related to bringing oxygen on the Moon, it is indeed pretty expensive:
    https://phys.org/news/2009-08-scient...ygen-moon.html

    But interestingly, NASA do have challenges to extract oxygen from the Moon rocks. I'm sure it's possible to do the same with hydrogen...

  21. #51
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    Quote Originally Posted by philippeb8 View Post
    Over time the cost of travelling to the Moon would be more affordable.
    You would be burning the vast majority of your hydrogen/oxygen for propellant. Meanwhile, your solar power would be limited to the same duty cycle on Earth, and you'd have to deal with all the other disadvantages of operating on the moon, like the two week long nights, temperature extremes, dust, etc.

    The cost of traveling to/from the moon is never going to drop enough for this to even come close to making sense.


    Quote Originally Posted by philippeb8 View Post
    According to a similar article, related to bringing oxygen on the Moon, it is indeed pretty expensive:
    https://phys.org/news/2009-08-scient...ygen-moon.html

    But interestingly, NASA do have challenges to extract oxygen from the Moon rocks. I'm sure it's possible to do the same with hydrogen...
    Rocks are mostly oxygen by mass. It is not possible to extract hydrogen from rocks, because there isn't any to extract.

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    Quote Originally Posted by philippeb8 View Post
    This is the only solution to fight emissions IMO but why havenít we found a cost effective solution for that yet?
    Well, considering you have to put energy INTO the hydrogen to make it in the first place, this isn't any sort of an energy solution at all. Hydrogen fuels cells are nothing more then a method of STORING energy, not of GENERATING energy. So even if we could snap our fingers right now and make every car on the road a hydrogen car and solve every problem with distribution and H2 storage, it actually wouldn't help one bit. We'd still have to burn an identical amount of fossil fuels after this as we did before.

    Sorry, but far from being the only solution to fight emissions, this isn't even one of the solutions to fight emissions.

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    Quote Originally Posted by Dave241 View Post
    Well, considering you have to put energy INTO the hydrogen to make it in the first place, this isn't any sort of an energy solution at all. Hydrogen fuels cells are nothing more then a method of STORING energy, not of GENERATING energy. So even if we could snap our fingers right now and make every car on the road a hydrogen car and solve every problem with distribution and H2 storage, it actually wouldn't help one bit. We'd still have to burn an identical amount of fossil fuels after this as we did before.

    Sorry, but far from being the only solution to fight emissions, this isn't even one of the solutions to fight emissions.
    I thought the hydrogen was coming from excess electricity from wind Mills and solar cells.
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    Quote Originally Posted by Copernicus View Post
    I thought the hydrogen was coming from excess electricity from wind Mills and solar cells.
    See post 15
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    Hydrogen engines

    Quote Originally Posted by Swift View Post
    Ok so if steam reforming is the most efficient way to produce hydrogen and carbon dioxide then is there an efficient way to do photosynthesis to convert the remaining carbon dioxide into oxygen?

    Just using steam reforming would end our dependency on other countries.


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    Quote Originally Posted by philippeb8 View Post
    Ok so if steam reforming is the most efficient way to produce hydrogen and carbon dioxide then is there an efficient way to do photosynthesis to convert the remaining carbon dioxide into oxygen?

    Just using steam reforming would end our dependency on other countries.
    Plants and algae are very good at photosynthesis. Unfortunately, humans not so much. We're getting a better understanding of it, but still have a long way to go before we can do it.
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    Quote Originally Posted by Jens View Post
    Plants and algae are very good at photosynthesis. Unfortunately, humans not so much. We're getting a better understanding of it, but still have a long way to go before we can do it.
    Are you serious? Then we should definitely open a research center on the subject!


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    Quote Originally Posted by philippeb8 View Post
    Are you serious? Then we should definitely open a research center on the subject!
    There are research centers trying to replicate photosynthesis.
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    Quote Originally Posted by philippeb8 View Post
    Are you serious? Then we should definitely open a research center on the subject!
    Google's take on current photosynthesis research
    Last edited by Noclevername; 2019-Oct-15 at 08:24 AM.
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    Quote Originally Posted by philippeb8 View Post
    It’s market analysis now... but let’s keep in mind hydrogen is lighter than petroleum so it could feed an engine for a longer period of time for the same volume of fuel.
    The low density of hydrogen is one of the problems. How do you compress it enough to provide the same energy density as petroleum, without the risks of explosion.

    Also since it’s profitable and risk-free (after a proper market analysis) then I’m sure venture capitalists will jump on the occasion to invest.
    I doubt very much it could be profitable. And it certainly isn't risk free. (The fact that venture capitalists have not jumped on the idea may be evidence enough.)

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