Engineers are developing new ways to convert greenhouse gases to fuel • Hacker News Board

Re: Engineers are developing new ways to convert greenhouse gases to fuel

#81

Post by wrycoder » Fri, Sep 24, 2021, 6:57 PM UTC

jl6 wrote: post #11

throwaway894345 wrote: post #2

The actual title is "UC reactor makes Martian fuel" and the subtitle is "A gas station on Mars? Engineers envision the possibilities." But the submission title is "UC reactor converts carbon dioxide to fuel to address climate change"? While it does talk about applications with respect to carbon capture, if we consume the fuel byproduct, presumably we just end up with co2 in the atmosphere? > “In the future we’ll deve…

> if we consume the fuel byproduct, presumably we just end up with co2 in the atmosphere? The process would still be great news if true, as it could be a carbon-neutral source of hydrocarbon fuel for applications that are hard to electrify, like aviation.

This is mainstream energy science.

Anthropogenic Chemical Carbon Cycle for a Sustainable Future [0]

How to Make Carbon-Neutral Gasoline Out of Thin Air [1]

[0] https://pubs.acs.org/doi/abs/10.1021/ja202642y#

[1] https://nymag.com/intelligencer/2021/05/how-to-make-carbon-n...

Re: Engineers are developing new ways to convert greenhouse gases to fuel

#82

Post by rolleiflex » Fri, Sep 24, 2021, 7:02 PM UTC

gpm wrote: post #24

lizknope wrote: post #13

The article claims they are already converting CO2 to fuel on the ISS. This process has been TESTED but we aren't using it right now. Article claims: > Known as the “Sabatier reaction” from the late French chemist Paul Sabatier, it’s a process the International Space Station uses to scrub the carbon dioxide from air the astronauts breathe and generate rocket fuel to keep the station in high orbit. Reality: We just sh…

The ISS uses rechargeable zeolite beds for CO2 scrubbing, they don't need a new one frequently, and the fact that we shipped a new one is coincidence. Zeolite is a mineral, you get a bunch of small pellets of it in a bed, and run air over it while cooling it. The CO2 (and H2O) stick to it while everything else goes over it. Once you're at capacity you vent it to space and heat it, the CO2 (and H2O) leave the bed (int…

If they’re not recycling CO2 into O2 and instead venting CO2 to space, does that mean ISS is constantly losing gas and it needs an ongoing resupply of oxygen all the time?

I thought oxygen was used fast enough to make resupply impractical, but perhaps there are in fact gigantic tanks of O2 under immense pressure somewhere aboard the ISS.

Re: Engineers are developing new ways to convert greenhouse gases to fuel

#83

Post by dTal » Fri, Sep 24, 2021, 7:03 PM UTC

dotancohen wrote: post #63

jl6 wrote: post #54

Earlier quoted context omitted.

To be clear, the solution to climate change is first to stop burning fossil fuels, and then to start removing carbon from the atmosphere. This technology won’t help long term removal of carbon if we just burn the resulting fuel, but it might help displace fossils as a source for some applications that would otherwise be at the very end of the fossil ramp-down.

There still must be some input of energy. From what I understand, the Sabatier reaction is really only viable from an environmental perspective if it is powered by some other non-carbon energy, such as solar or wind.

And if you have that surplus clean energy, you should spend it powering things that would otherwise be powered with fossil fuels - not trying to offset someone else's emissions. Carbon removal only makes sense in a world where nobody is burning any fossil fuels, and we're trying to lower atmospheric carbon. Lower, not offset.

Re: Engineers are developing new ways to convert greenhouse gases to fuel

#84

Post by mzs » Fri, Sep 24, 2021, 7:12 PM UTC

rolleiflex wrote: post #82

gpm wrote: post #24

Earlier quoted context omitted.

The ISS uses rechargeable zeolite beds for CO2 scrubbing, they don't need a new one frequently, and the fact that we shipped a new one is coincidence. Zeolite is a mineral, you get a bunch of small pellets of it in a bed, and run air over it while cooling it. The CO2 (and H2O) stick to it while everything else goes over it. Once you're at capacity you vent it to space and heat it, the CO2 (and H2O) leave the bed (int…

If they’re not recycling CO2 into O2 and instead venting CO2 to space, does that mean ISS is constantly losing gas and it needs an ongoing resupply of oxygen all the time? I thought oxygen was used fast enough to make resupply impractical, but perhaps there are in fact gigantic tanks of O2 under immense pressure somewhere aboard the ISS.

https://en.wikipedia.org/wiki/ISS_ECLSS#Oxygen_generating_sy...

Re: Engineers are developing new ways to convert greenhouse gases to fuel

#85

Post by gpm » Fri, Sep 24, 2021, 7:13 PM UTC

rolleiflex wrote: post #82

gpm wrote: post #24

Earlier quoted context omitted.

The ISS uses rechargeable zeolite beds for CO2 scrubbing, they don't need a new one frequently, and the fact that we shipped a new one is coincidence. Zeolite is a mineral, you get a bunch of small pellets of it in a bed, and run air over it while cooling it. The CO2 (and H2O) stick to it while everything else goes over it. Once you're at capacity you vent it to space and heat it, the CO2 (and H2O) leave the bed (int…

If they’re not recycling CO2 into O2 and instead venting CO2 to space, does that mean ISS is constantly losing gas and it needs an ongoing resupply of oxygen all the time? I thought oxygen was used fast enough to make resupply impractical, but perhaps there are in fact gigantic tanks of O2 under immense pressure somewhere aboard the ISS.

Yes, and sort of.

The ISS is constantly losing gas, I believe that the primary source of new O2 is actually electrolysis of water, not pressurized tanks, but that they do also have pressurized tanks as a backup.

A person breathes out roughly 1kg of CO2/day, and it follows you breathe in about the same amount of O2, not an impossible amount of mass to resupply.

Re: Engineers are developing new ways to convert greenhouse gases to fuel

#86

Post by SV_BubbleTime » Fri, Sep 24, 2021, 7:20 PM UTC

invisible wrote: post #42

It's been seemingly impossible to motivate the world to switch to alternatives to fuel. We're between a rock and a hard place with society and the environment. It seems like there isn't even a conspiracy, it's just a combination of poor choices, greed, and new technology. Solar is great, but often it's more expensive than just consuming grid power or has unpredictable payoffs. Wind has a lot of upfront costs. Massive…

> It's been seemingly impossible to motivate the world to switch to alternatives to fuel.

The impossible part is we have yet to discover a density/cost comparison to hydrocarbons.

No one is going to “switch” to something that isn’t as good as the existing option. Couple this with “but electric cars!” that often are still just coal powered.

Plastics, military, actual logistics, China, we’re going to burn every drop of oil. We all better hope someone is working on sequestering options!

Re: Engineers are developing new ways to convert greenhouse gases to fuel

#87

Post by rtkwe » Fri, Sep 24, 2021, 7:22 PM UTC

gpm wrote: post #24

lizknope wrote: post #13

The article claims they are already converting CO2 to fuel on the ISS. This process has been TESTED but we aren't using it right now. Article claims: > Known as the “Sabatier reaction” from the late French chemist Paul Sabatier, it’s a process the International Space Station uses to scrub the carbon dioxide from air the astronauts breathe and generate rocket fuel to keep the station in high orbit. Reality: We just sh…

The ISS uses rechargeable zeolite beds for CO2 scrubbing, they don't need a new one frequently, and the fact that we shipped a new one is coincidence. Zeolite is a mineral, you get a bunch of small pellets of it in a bed, and run air over it while cooling it. The CO2 (and H2O) stick to it while everything else goes over it. Once you're at capacity you vent it to space and heat it, the CO2 (and H2O) leave the bed (int…

The new scrubber sounds like it's not using the old zeolite bed system but one based on molecular sieves. But you're otherwise right that they're not really turning that CO2 into anything on the regular beyond the limited ISRU experiment(s).

Re: Engineers are developing new ways to convert greenhouse gases to fuel

#88

Post by gpm » Fri, Sep 24, 2021, 7:28 PM UTC

rtkwe wrote: post #87

gpm wrote: post #24

Earlier quoted context omitted.

The ISS uses rechargeable zeolite beds for CO2 scrubbing, they don't need a new one frequently, and the fact that we shipped a new one is coincidence. Zeolite is a mineral, you get a bunch of small pellets of it in a bed, and run air over it while cooling it. The CO2 (and H2O) stick to it while everything else goes over it. Once you're at capacity you vent it to space and heat it, the CO2 (and H2O) leave the bed (int…

The new scrubber sounds like it's not using the old zeolite bed system but one based on molecular sieves. But you're otherwise right that they're not really turning that CO2 into anything on the regular beyond the limited ISRU experiment(s).

Zeolite is a molecular sieve. That's just a fancy word for "material that selectively holds on to some types of gasses" (CO2 and H2O in the case of zeolite).

I haven't followed the new bed system though, I'd be very interested to know if it was using a different molecular sieve (and somewhat surprised if they are).

Re: Engineers are developing new ways to convert greenhouse gases to fuel

#89

Post by jandrese » Fri, Sep 24, 2021, 7:28 PM UTC

bialpio wrote: post #12

I wish they addressed the fact that methane that they will be producing is said to be an even more potent greenhouse gas than carbon dioxide. Are there any worries about the leakage for example?

Starting a greenhouse effect on Mars would help it become more livable by humans.

Re: Engineers are developing new ways to convert greenhouse gases to fuel

#90

Post by rtkwe » Fri, Sep 24, 2021, 7:29 PM UTC

asasidh wrote: post #67

convert Co2 to methane which is a more potent agent for global warming. what could go wrong

For Mars that's not so much of an issue. Even if we did release a lot of methane warming up Mars isn't a bad thing in fact it's something we may try eventually intentionally to make it less inhospitable.