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Engineers are developing new ways to convert greenhouse gases to fuel

uc.edu

21–30 of 213 posts

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

#21
post #19

Earlier quoted context omitted.

Thermodynamics is about energy not CO2, you can design negative CO2 devices and we even have proof in nature of that since that's what trees are doing.

There are several conceptual issues here, but one of them is that trees require energy from sunlight to turn CO2 into other things.

Yes but we don't have an energy problem, we have a CO2 problem and there's no law of physics preventing to absorb more CO2 than you emit.

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

#22
post #15

No, enough with this nonsense. Capturing, liquefying and transforming CO2 into fuel requires energy - due to thermodynamic limits, much more energy than what the fuel can give back. You then take that fuel, and... burn it into 25% efficient engines that spew the very same CO2 back into the air, along with some new carcinogenic fumes and acid-rain inducing nitrogen oxides? No, just no, full stop. They way forward is e…

Thermodynamics is about energy not CO2, you can design negative CO2 devices and we even have proof in nature of that since that's what trees are doing.

But thats not what this is. Fuel is intended to be consumed, seems like this is at best carbon neutral assuming totally neutral power source. Are our current power sources on average neutral or are they much more carbon positive?

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

#23
post #11

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.

I just imagine the scramble to get carbon neutral allowing huge carbon-processing factories and then we enter some kind of carbon deficit, back in the same situation we are in—a teetering balance between overconsumption and moderation.

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

#24

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 (into space) and recharge it for the next cycle. Repeat forever.

The consumables here are the small amount of gasses sent overboard, and energy, nothing else.

(And you use multiple of these beds because capturing CO2 is exothermic, and venting CO2 is endothermic, so you want to run a heat exchanger between the two beds in opposite cycles to minimize energy usage)

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

#25
post #15

No, enough with this nonsense. Capturing, liquefying and transforming CO2 into fuel requires energy - due to thermodynamic limits, much more energy than what the fuel can give back. You then take that fuel, and... burn it into 25% efficient engines that spew the very same CO2 back into the air, along with some new carcinogenic fumes and acid-rain inducing nitrogen oxides? No, just no, full stop. They way forward is e…

I get that blue hydrogen might be a controversial topic but isn't there at least a case to make for green hydrogen in some sectors that might be hard to electrify such as aviation? Or even as an alternative storage solution since the effort to scale up nuclear seems pretty much dead in the water.

I know it is a long shot: it is not yet competitive, there are still very few electrolyzers but some part of the world such as Europe seems pretty committed to try to make it work.

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

#26
post #15

No, enough with this nonsense. Capturing, liquefying and transforming CO2 into fuel requires energy - due to thermodynamic limits, much more energy than what the fuel can give back. You then take that fuel, and... burn it into 25% efficient engines that spew the very same CO2 back into the air, along with some new carcinogenic fumes and acid-rain inducing nitrogen oxides? No, just no, full stop. They way forward is e…

The title needs to be changed. Because this isn't about climate change, and the research, contents of the article, and current article title are clear on that.

This is about space exploration. Literally it is about how to make fuel on Mars so that we can make the round trip without having to deliver fuel so we can make it back.

And, sorry, but there is no way with current technology to launch significant payloads into space using electric.

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

#27
post #15

No, enough with this nonsense. Capturing, liquefying and transforming CO2 into fuel requires energy - due to thermodynamic limits, much more energy than what the fuel can give back. You then take that fuel, and... burn it into 25% efficient engines that spew the very same CO2 back into the air, along with some new carcinogenic fumes and acid-rain inducing nitrogen oxides? No, just no, full stop. They way forward is e…

It can make sort of sense for applications for which the energy density of the fuel (like for airplanes or rockets) matters a lot. The energy density of current generation lithium ion batteries is insufficient to allow for long-range flights. Synthetic fuels could allow planes to still travel around the world while being effectively net zero emitters because the CO_2 was harvested from the atmosphere (or another, unavoidable CO_2 source). The production of the fuel might be inefficient but at least it would work.

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

#28
post #15

No, enough with this nonsense. Capturing, liquefying and transforming CO2 into fuel requires energy - due to thermodynamic limits, much more energy than what the fuel can give back. You then take that fuel, and... burn it into 25% efficient engines that spew the very same CO2 back into the air, along with some new carcinogenic fumes and acid-rain inducing nitrogen oxides? No, just no, full stop. They way forward is e…

We'll just use that fuel to make plastic, and scatter it all over the surface of the planet. So it's really just a continuation of the ad hoc sequestration program already under way.

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

#29
post #15

No, enough with this nonsense. Capturing, liquefying and transforming CO2 into fuel requires energy - due to thermodynamic limits, much more energy than what the fuel can give back. You then take that fuel, and... burn it into 25% efficient engines that spew the very same CO2 back into the air, along with some new carcinogenic fumes and acid-rain inducing nitrogen oxides? No, just no, full stop. They way forward is e…

Thermodynamics is about energy not CO2, you can design negative CO2 devices and we even have proof in nature of that since that's what trees are doing.

The problem is that this requires reversing entropy. Turning CO2 into something that can burn into CO2 requires more energy than you get back while burning it, even in an optimal engine. This is true if humans reverse entropy or if trees do it.

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

#30

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…

There's more than one actual title. The submitter used the HTML doc title, which is a legit choice, and they probably picked it on the grounds that it was more substantive/less baity.

Since the climate change mention has turned out to be baity in its own right, I took that bit out above.

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