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> When air was bubbled through potassium hydroxide dissolved in ethylene glycol and the CO2-loaded solution subsequently hydrogenated in the presence of H2 and

> When air was bubbled through potassium hydroxide dissolved in ethylene glycol and the CO2-loaded solution subsequently hydrogenated in the presence of H2 and a metal catalyst, complete conversion to methanol was observed at 140 °C. Am I missing something? Isn't the need for hydrogen gas here a constraint? It's either gonna be refined (steam reforming) or split from water.

pfdietz 4y ago
This scheme is combining synfuel production with CO2 capture, which is kind of cute. The hydrogen is serving two functions: it makes methanol, but it also regenerates the alkaline CO2 capture solution.
tuatoru 4y ago
H2 is necessary, yes. It can be provided by electrolysis of water, air captured if necessary.
- eganist 4y ago
  Yeah that feels like it defeats the point. Not that I know the math, but it feels like there's a potential for it to be a net contributor of carbon emissions by encouraging more steam reforming of cng (and thus more cng pumping) or through power consumed to split water—power which invariably will come from dirty sources until we've done a better job moving away from dirty power. I'd be curious to see someone graph out where this transitions from being carbon positive to being carbon negative (or vice versa)
  - PaulHoule 4y ago
    No, e-Fuels like this are a way to make fuel from carbon free sources and that means splitting water to make hydrogen and sucking CO2 out of the air. The navy is interested in making e-fuels from electricity on nuclear aircraft carriers since a gallon of jet fuel delivered to an aircraft carrier costs a lot more than a gallon of jet fuel delivered to a civilian airport and the aircraft carrier has to slow down a lot so a tanker it refuels from can catch up with it.
  - DennisP 4y ago
    The point is not to get free energy. The point is to turn energy into hydrocarbon fuels that can be used without net carbon emissions, especially for vehicles that aren't easy to electrify.
    - SoftTalker 4y ago
      Yes, this sort of thing is best thought of as a different sort of battery. You put energy in, and later get energy out. It's not a fuel. If you could do it with solar power, it's sort of like free energy but no more than charging batteries from solar is. There are still infrastructure costs at minimum.
    - jalk 4y ago
      Potentially also as way of storing excess wind/solar generated energy
  - bryanlarsen 4y ago
    Here's a scale model of a methane production plant https://twitter.com/TerraformIndies/status/1591255472572895233/photo/1 https://twitter.com/TerraformIndies/status/15912554725728952... If you burn gas to create gas, you end up with less gas than you started with. It'd be cheaper to burn dollar bills. It only works when the input energy is cheaper than the output energy. Right now solar and wind are the only energy sources cheaper than fossil energy.
retrac 4y ago
The point is that methanol is a liquid which you can pour into a tank like regular gasoline and will run with many existing engine designs. It is also useful for a variety of industrial purposes. Similarly, methane can be piped in existing natural gas infrastructure and burned in existing boilers. Hydrogen, by comparison, is hard to store, harder to work with, and lower density. There is no readily available carbon-neutral substitute for aviation fuel, gasoline, artificial fertilizers, or even natural gas. Synthesis from carbon-neutral power would provide it. Germany liquefied coal into methane and methanol at an industrial scale during WW II due to lack of oil imports. This is the same idea, just switching the heat and CO2 and H2 to a different source besides coal. It's also possible to synthesize ammonia (fundamental to synthetic fertilizers and all kinds of chemistry) from H2 + N2 + C02 + heat in the presence of a catalyst.
- pfdietz 4y ago
  Why is hydrogen itself, turned into ammonia, not a substitute for use of fossil fuels to make artificial fertilizers. Sure, urea contains carbon, but there are plenty of N fertilizers other than urea.
- kyleyeats 4y ago
  Ethanol is a carbon-neutral substitute for gasoline, no?
  - Schroedingersat 4y ago
    Crop ethanol uses an extremely large amount of land for the energy. US corn ethanol uses about 2 acres to support one car. And this has a large fossil fuel input (possibly with a net carbon output depending on fertilizer use and how it's distilled). For a rough efficiency comparison, if there were some hypothetical 80% efficient solar panel and annual storage wasn't a concern, it could power the car with just the sunlight that hit it.
  - fooker 4y ago
    Ethanol can be potentially carbon neutral, given a ton of terms and preconditions.
thinkcontext 4y ago
Yes it still requires hydrogen like normal gas to liquid processes. The innovation is that carbon capture and methanol production happen as part of the same process. This has the potential to make it much more efficient than doing two separate processes.

pfdietz 4y ago

This scheme is combining synfuel production with CO2 capture, which is kind of cute. The hydrogen is serving two functions: it makes methanol, but it also regenerates the alkaline CO2 capture solution.

tuatoru 4y ago

H2 is necessary, yes. It can be provided by electrolysis of water, air captured if necessary.

eganist 4y ago
Yeah that feels like it defeats the point. Not that I know the math, but it feels like there's a potential for it to be a net contributor of carbon emissions by encouraging more steam reforming of cng (and thus more cng pumping) or through power consumed to split water—power which invariably will come from dirty sources until we've done a better job moving away from dirty power. I'd be curious to see someone graph out where this transitions from being carbon positive to being carbon negative (or vice versa)
- PaulHoule 4y ago
  No, e-Fuels like this are a way to make fuel from carbon free sources and that means splitting water to make hydrogen and sucking CO2 out of the air. The navy is interested in making e-fuels from electricity on nuclear aircraft carriers since a gallon of jet fuel delivered to an aircraft carrier costs a lot more than a gallon of jet fuel delivered to a civilian airport and the aircraft carrier has to slow down a lot so a tanker it refuels from can catch up with it.
- DennisP 4y ago
  The point is not to get free energy. The point is to turn energy into hydrocarbon fuels that can be used without net carbon emissions, especially for vehicles that aren't easy to electrify.
  - SoftTalker 4y ago
    Yes, this sort of thing is best thought of as a different sort of battery. You put energy in, and later get energy out. It's not a fuel. If you could do it with solar power, it's sort of like free energy but no more than charging batteries from solar is. There are still infrastructure costs at minimum.
  - jalk 4y ago
    Potentially also as way of storing excess wind/solar generated energy
- bryanlarsen 4y ago
  Here's a scale model of a methane production plant https://twitter.com/TerraformIndies/status/1591255472572895233/photo/1 https://twitter.com/TerraformIndies/status/15912554725728952... If you burn gas to create gas, you end up with less gas than you started with. It'd be cheaper to burn dollar bills. It only works when the input energy is cheaper than the output energy. Right now solar and wind are the only energy sources cheaper than fossil energy.

retrac 4y ago

The point is that methanol is a liquid which you can pour into a tank like regular gasoline and will run with many existing engine designs. It is also useful for a variety of industrial purposes. Similarly, methane can be piped in existing natural gas infrastructure and burned in existing boilers. Hydrogen, by comparison, is hard to store, harder to work with, and lower density. There is no readily available carbon-neutral substitute for aviation fuel, gasoline, artificial fertilizers, or even natural gas. Synthesis from carbon-neutral power would provide it. Germany liquefied coal into methane and methanol at an industrial scale during WW II due to lack of oil imports. This is the same idea, just switching the heat and CO2 and H2 to a different source besides coal. It's also possible to synthesize ammonia (fundamental to synthetic fertilizers and all kinds of chemistry) from H2 + N2 + C02 + heat in the presence of a catalyst.

pfdietz 4y ago
Why is hydrogen itself, turned into ammonia, not a substitute for use of fossil fuels to make artificial fertilizers. Sure, urea contains carbon, but there are plenty of N fertilizers other than urea.
kyleyeats 4y ago
Ethanol is a carbon-neutral substitute for gasoline, no?
- Schroedingersat 4y ago
  Crop ethanol uses an extremely large amount of land for the energy. US corn ethanol uses about 2 acres to support one car. And this has a large fossil fuel input (possibly with a net carbon output depending on fertilizer use and how it's distilled). For a rough efficiency comparison, if there were some hypothetical 80% efficient solar panel and annual storage wasn't a concern, it could power the car with just the sunlight that hit it.
- fooker 4y ago
  Ethanol can be potentially carbon neutral, given a ton of terms and preconditions.

thinkcontext 4y ago

Yes it still requires hydrogen like normal gas to liquid processes. The innovation is that carbon capture and methanol production happen as part of the same process. This has the potential to make it much more efficient than doing two separate processes.