Ask HN: Does hobbyist-level C02 recapture make sense?
This post really interested me.
I asked a fellow HackerNews reader (Rod Fitzsimmons Frey) for his thoughts on the post. He kindly responded with the following outline of steps:
- Capture of CO2 from the atmosphere using a variety of techniques, usually adsorption (https://en.wikipedia.org/wiki/Carbon_capture_and_storage). This takes quite a bit of energy.
- Conversion of the dissolved CO2 into alcohols. Reaction is 2CO2 + 9H2O + 12e- → C2H5OH + 12OH- so it's energy-uphill and needs an energy input. Maybe solar cells or a wind turbine. Requires a catalyst, often a variety of copper matrix. Catalysts are the major subject of research. To figure out whether you could do this in your garage you'd probably need to go to the literature.
- Distillation of the alcohols - usually done with heat, requires 800-900 deg C. Possible but hard and energy intensive. This is where Prometheus sits, they have a nanoscale membrane that does room-temperature separation of the alcohols using electricity input (more energy in!)
- Conversion of the alcohols into gasoline, diesel, kerosene etc. This is a pretty well-known process that uses a catalyst called ZSM-5 plus heat (mo' mo' energy!). I haven't looked into the chemistry or the availability of the catalyst.
I think it's pretty clear that... it's most likely not possible to convert C02 into gasoline without using more energy + money than it would take to just go buy a $2.69/gallon of 87 unleaded.
However, what is possible/makes sense at a consumer level? In a modern day society where more and more individuals are learning the impact of climate change, I feel like any form of CO2 recapture + distillation would be a solid business idea from a "demand" standpoint.