CH4 + H2O → CO + H2
CO + 2 H2 → CH3OH
Direct reduction of CO2 to methanol without going through the methane, an already established technology (Fischer-Tropsch type chemistry):
CO2 + 3H2 → CH3OH + H2O
Methanol is a common feedstock for further chemical synthesis (such as making high-octane gasoline), so this is an option for fuels from direct air capture of carbon dioxide & electrolysis of water for hydrogen. Two methanol molecules are dehydrated to form dimethyl ether (CH3-O-CH3) as the initial step:
> "Methanol can be used to make a gasoline product. The process uses a special zeolite catalyst with pore size such that molecules up to C10 can get out of the catalyst. Larger molecules cannot be made with this process; therefore, a product is made with no carbon molecules greater than C10, which boils in the gasoline range. In this process, aromatics and branched-chain alkanes are made, which means the MTG process produces very high octane gasoline. Gasoline is the only product."
When used for fuel cells, methanol does not have the storage problems of hydrogen, even if any equipment using methanol must be designed carefully, to avoid any leaks, which are dangerous because methanol is toxic and may cause blindness when ingested or absorbed through the skin.
It's not super efficient, but I am pretty sure you're not going to improve that by introducing an intermediate step.
What's the foundation of that argument? An intermediate step that's achieved more efficiently and allows for a more efficient follow-up certainly can improve the efficiency of the overall process compared to one with less steps?
If it's possible you go from A->B at 80% efficiency. If we compare this with A->C then C->B need to be nearly twice as efficient to provide a better yield.
Remember these steps include losses due to non chemical reasons. You might have issues with your reactors or transferring the solution to a new reaction chamber might incur losses, etc.
In most complex organic synth situations, the full synthesis will be 8-20 steps or so, so we're talking about yields of %efficiency^x. Lowering X helps a ton.
In short, the alternate route needs to be really good to justify additional steps.
Isn’t that the entire reasons catalysts are so valuable?
Perhaps we could so with a llittle self-awareness?
To come here and simply state that all these PHDs develop a new process while you here rest in certainty that it is doomed to failure.
Without demonstrating any understanding of catalysts or anything beyong highschool chemistry. Without presenting any evidence or agument except 'extra step is bad'
This is all known technology, the problem is it's not very efficient. Ultimately the discussion in climate tech circles these days is usually that most people think you'll rarely ever do this. Whenever you can you'll use something more direct, like using Hydrogen directly as an energy carrier.
The YouTube video (“burning saltwater”) is a classic—but there still isn’t a proper study on the efficiency of the process. (The radio technician, John Kanzius, died of cancer).
Edit: here is a scientific paper characterizing the process, which is pretty interesting. No calculation of efficiency, however. https://iopscience.iop.org/article/10.1088/0963-0252/22/1/01...
The paper I posted uses a focused beam of RF and more deliberate lab methodology. But with just 5 citations, I feel like there might be a missed opportunity.
Even if it’s not efficient this is a great RF science demo so it’s good to spread the knowledge around. Thanks again for posting it.
They have used 13.56 MHz just because it is one of the frequencies for which it is easy to find high power industrial generators, which are used e.g. for induction heating.
* We build arrays of underwater resonating tubes (~ 17 m for 13.58 MHz) that optimize the RF process efficiency for generating hydrogen.
* Out in the open ocean, it’s powered by floating gigawatt solarpads.
* “Blossoms” of enormous mylar cells are continuously filled up with hydrogen.
* The mylar hydrogen cells are plucked and transported for further processing via drone zeppelins.
Almost always, people think one new idea is as much as a new technology can take.
But I suspect people will prefer an underwater hose for transporting gases.
I just looked it up. Hydrogen is insoluble in water. Oxygen is quite soluble. So, circulating water through, the hydrogen will bubble out, while the oxygen will be carried away with the water. So, maybe no semipermeable membranes needed.
Does oxygen dissolve more readily in water than does hydrogen? If so, you just keep a continuous flow of water so it doesn't saturate before it moves on, but the hydrogen still bubbles out.
I doubt you want the water hanging about, heating up, anyway.
That said everything would be more flammable.
It was actually before dinosaurs (Devonian and Cambrian Periods).
Analogously, there's nothing about the atmosphere preventing giant ground sloths from existing, but they nevertheless can't exist because they're not compatible with humans.
We don't know whether they would have coexisted with us. E.g., hippo population in Columbia is exploding. Megatherium sp. coexisted with hunter-gatherer humans for at least thousands of years.
Horses and camels can coexist with humans. They too were obliterated in the Americas by the comet strike.
But we anyway know people did hunt all of them, before that.
Luckily, all the damage is already done, and our ecosystem is now well adapted to living in a bath of toxic gas.
Water is similar.
The essence of life is turning things into other things; doing so is difficult and dangerous.
> "The process is 100% selective—meaning there is no undesirable by-product—comparable with methane monooxygenase, which is the enzyme in nature for this process."
It seems like it should be pretty easy to get any given enzyme mass-produced. What is the reason we're not just growing a bunch of methane monooxygenase and using it to convert methane?
Probably the same as every other eco-friendly "get rich quick" scheme - the precursors are relentlessly unpleasant.
"So all you need to do is take your water and yeast and cellulose and put it into a container, then slowly add the uranobenzene and methylated lead, bubble some nickel carbonyl through it, and gently warm it up to 900°C..."
It seems like a safe bet that production and use of an organic protein are best accomplished at temperature ranges normally maintained by whatever life forms naturally produce it.
That makes me think of this quote: "The heater was warmed to approximately 700C. The heater block glowed a dull red color, observable with room lights turned off. The ballast tank was filled to 300 torr with oxygen, and fluorine was added until the total pressure was 901 torr. . ."
from: https://www.science.org/content/blog-post/things-i-won-t-wor...
These problems notably plague attempts to use the even-holier grail of nitrogenases, basically enzymes for synthesizing ammonia using N2 and water. The current standard process for industrially fixing nitrogen (the Haber-Bosch process) is energy-inefficient and uses about 1-2% of the world's total energy supply, mostly in the form of natural gas. So significantly reducing its energy usage would be a huge deal, but we haven't been able to do it, nor do we fully understand how nitrogenases even work.
You could also try to culture bacteria that do the whole process and maintain the enzymes for you. In the case of methanol synthesis though, even if you could do this you'd have to keep tes culture alive and working 24/7 at a remote industrial site. A flare stack is a lot simpler.