6 ms·

For those just reading the headline, this is for producing syngas / kerosene precursors, not for splitting to C + O2.

PaulHoule 3y ago
Splitting to CO and O2. Not sure if you'd ever really want to split to C + O2 if you were interested in making something that wasn't graphene or some carbon compound like that.
- mdorazio 3y ago
  If your goal is to get carbon out of the atmosphere instead of keeping it bound up in a fuel > CO2 > fuel cycle then splitting to C + O2 is exactly what you want to do. I.e., the same thing trees do; true carbon sequestration rather than repurposing.
  - PaulHoule 3y ago
    Well.. The trees are actually turning H2O and CO2 into carbohydrates which are a lot like hydrocarbons in that they can be an energy carrier (propane/sugars/starches) or a structural material (polyethylene/cellulose/lignin) It's been proposed that you could sequester carbon by making plastic pellets and burying them, for instance. (For that matter you can partially burn the trees to make a carbon-rich "biochar" which is one of the most powerful soil amendments known.) People who just want to take carbon waste from an industrial process or the atmosphere and just "make it disappear" are mostly happy to concentrate the CO2 and then pump it underground and not have to do the "work" of converting low energy CO2 into some other product. From a material handling perspective you can pipe the supercritical fuel 200 miles away without loaders and dump trucks and trains and similar hassles. I think though there is an "e-fuels" market in that someone is going to want to have fossil fuel independent chemistry: for instance the U.S. Navy would love to use nuclear electricity to make aircraft fuel on an aircraft carrier so that the carrier never needs to slow down to take on fuel. With a sufficiently high carbon tax, for instance, e-Fuels could be cheaper to end users than fossil fuels. I think it's an interesting technology for space exploitation in that the factory of a space colony has to produce all sort of carbon, hydrogen, oxygen, nitrogen and similar organic compounds to support biology and technology. Some asteroids contain huge amounts of "coal" and carbonates and also water and silicates and it would need some system to turn the coal into organic chemicals (like 20 billion kg of Kapton plastic film for solar sails, sun shades, stuff like that) They would never dispose of waste CO2 because it so precious and certainly they have a system that recycles the carbon... One of those solar reactors would be perfect for always shining sun out there.
    - jszymborski 3y ago
      I have long wondered why we don't make tonnes of dense bioplastics (like PLA) and burrying them as a means of offsetting CO2 emissions.
      - bobim 3y ago
        Because the company making the PLA wants to make profit out of it? It’s wild how we can imagine anything that would help us to continue derping around at full tilt, but totally lack imagination when it comes about simply slowing down.
      - Retric 3y ago
        We do, it’s called a dump. One downside is they tend to produce a fair bit of methane, but they potentially sequester CO2 across geologic timescales. The other is most of the plastic was sourced from fossil fuels and releases CO2 as part of the manufacture process so it’s not a net gain. Still better than burning it though.
        ZeroGravitas 3y ago
        It's not better than burning it in a facility that captures the energy, even more so if that energy is displacing fossil fuels from electric or home heating grids.
        soco 3y ago
        But isn't burning it releasing again the CO2, and sequestrating this was the point of the exercise in the first place?
        ZeroGravitas 3y ago
        We care about CO2 equivalent, so anything that leaks methane is a candidate for being burned instead to reduce impact. And plastic leaks methane from dumps.

Splitting to CO and O2. Not sure if you'd ever really want to split to C + O2 if you were interested in making something that wasn't graphene or some carbon compound like that.

mdorazio 3y ago
If your goal is to get carbon out of the atmosphere instead of keeping it bound up in a fuel > CO2 > fuel cycle then splitting to C + O2 is exactly what you want to do. I.e., the same thing trees do; true carbon sequestration rather than repurposing.
- PaulHoule 3y ago
  Well.. The trees are actually turning H2O and CO2 into carbohydrates which are a lot like hydrocarbons in that they can be an energy carrier (propane/sugars/starches) or a structural material (polyethylene/cellulose/lignin) It's been proposed that you could sequester carbon by making plastic pellets and burying them, for instance. (For that matter you can partially burn the trees to make a carbon-rich "biochar" which is one of the most powerful soil amendments known.) People who just want to take carbon waste from an industrial process or the atmosphere and just "make it disappear" are mostly happy to concentrate the CO2 and then pump it underground and not have to do the "work" of converting low energy CO2 into some other product. From a material handling perspective you can pipe the supercritical fuel 200 miles away without loaders and dump trucks and trains and similar hassles. I think though there is an "e-fuels" market in that someone is going to want to have fossil fuel independent chemistry: for instance the U.S. Navy would love to use nuclear electricity to make aircraft fuel on an aircraft carrier so that the carrier never needs to slow down to take on fuel. With a sufficiently high carbon tax, for instance, e-Fuels could be cheaper to end users than fossil fuels. I think it's an interesting technology for space exploitation in that the factory of a space colony has to produce all sort of carbon, hydrogen, oxygen, nitrogen and similar organic compounds to support biology and technology. Some asteroids contain huge amounts of "coal" and carbonates and also water and silicates and it would need some system to turn the coal into organic chemicals (like 20 billion kg of Kapton plastic film for solar sails, sun shades, stuff like that) They would never dispose of waste CO2 because it so precious and certainly they have a system that recycles the carbon... One of those solar reactors would be perfect for always shining sun out there.
  - jszymborski 3y ago
    I have long wondered why we don't make tonnes of dense bioplastics (like PLA) and burrying them as a means of offsetting CO2 emissions.
    - bobim 3y ago
      Because the company making the PLA wants to make profit out of it? It’s wild how we can imagine anything that would help us to continue derping around at full tilt, but totally lack imagination when it comes about simply slowing down.
    - Retric 3y ago
      We do, it’s called a dump. One downside is they tend to produce a fair bit of methane, but they potentially sequester CO2 across geologic timescales. The other is most of the plastic was sourced from fossil fuels and releases CO2 as part of the manufacture process so it’s not a net gain. Still better than burning it though.
      - ZeroGravitas 3y ago
        It's not better than burning it in a facility that captures the energy, even more so if that energy is displacing fossil fuels from electric or home heating grids.
        soco 3y ago
        But isn't burning it releasing again the CO2, and sequestrating this was the point of the exercise in the first place?
        ZeroGravitas 3y ago
        We care about CO2 equivalent, so anything that leaks methane is a candidate for being burned instead to reduce impact. And plastic leaks methane from dumps.