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Engineers are developing new ways to convert greenhouse gases to fuel

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

#181

Post by ncmncm »

tgsovlerkhgsel wrote: post #173
ncmncm wrote: post #102

Earlier quoted context omitted.

Current SF6 level (four orders of magnitude more heat-trapping than CO2, by weight) accounts for 10% of heat forcing. How the heck do we get that stuff out of the atmosphere? There is a replacement, now, for SF6, for use in power stations and wind turbines. Now the SF6 in use needs to be pumped out and disposed of safely, and SF6 actually banned. And, we have to persuade China to replace theirs too.

> Current SF6 level (...) accounts for 10% of heat forcing. Source? This does not match what https://en.wikipedia.org/wiki/IPCC_list_of_greenhouse_gases says. In my naive mind, Methane seems like the it could be a good candidate for removal from atmosphere: If you could just get it to react with oxygen, it turns into water and the much less harmful CO2, so you don't have to sequester anything, and the reaction is exo…

https://en.wikipedia.org/wiki/Sulfur_hexafluoride#Greenhouse... :

"the collective contribution of [SF6] and similar man-made halogenated gases has reached about 10 percent as of year 2020". But reading more closely, it seems the SF6 by itself is much less. The rest, I guess, must be CFCs and HFCs.

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

#182

Post by ncmncm »

_Microft wrote: post #140
yholio wrote: post #106

Earlier quoted context omitted.

There is already a good solution for planes: ammonia, manufactured efficiently from green hydrogen. You will never be able to use gaseous or liquid hydrogen on planes due to the high volume, weight and risk associated with known storage methods. Ammonia seems to strike the right balance: https://www.ammoniaenergy.org/articles/zero-emission-aircraf...

How are they planning to work around ammonia's toxicity problem? It's fatal if breathed in at concentrations like we currently have CO_2 in the atmosphere (> ~400ppm). If a tank with conventional jetfuel or methane springs a leak or has to be dumped, you've got a huge problem. If that happens with an ammonia tank, you are most likely toast either way.

Millions of tons of ammonia are produced every year. It is the favored refrigerant in industrial sites, such as warehouse-sized freezers. We have most of a century's experience handling ammonia in such quantities.

But ammonia is probably a better choice for fueling trains and ships than for aircraft.

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

#184

Post by noobermin »

Manuel_D wrote: post #133
ehsankia wrote: post #130

Earlier quoted context omitted.

Pulling it out of the air isn't feasible. What about pulling it right where it's mostly produced (heavy polluting factories or electricity generators).

Capturing it is difficult. It's coming out the end of a turbine or smelter at very high temperatures. You need to cool it and compress it down. Then you need to secure a source of hydrogen. Over 90% of industrial hydrogen comes from steam reforming which emits CO2. So you'd need to build out massive electrolysis plants, and power these plants with carbon-free energy. Finally you'd need to run the Sabatier process, wh…

Thank you, whenever these articles come out, people forget CO2 IS the lower energy state and while these catalysts can help, you still need energy to supply the H2...which requires you to burn coal/gas which makes CO2. It's not like there's a "CO2 always increases with every reaction" law like the 2nd law of thermo, but it isn't easy otherwise we'd all be doing that as it would be a hell lot easier to do that than the other things we need to do to combat climate change.

Burning organic anything makes water and CO2, amongst the most stable (read lower energy) chemicals in the world. If you want to break one of those up, you need to increase entropy some other way, and unless we're talking solar, wind, or nuclear energy, you're going to have to make more water and CO2 (burn more coal) to do it.

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

#185

Post by jschwartzi »

adolph wrote: post #183

I’m looking forward to seeing the new chemical solar cells that take the carbon from carbon dioxide and place it into polymer chains of molecules that can be used as a fuel source or maybe material for 3D printing.

Yeah I read they’re going to have the solar cells print their own supports out of lignin.

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

#186

Post by yholio »

diarrhea wrote: post #121
yholio wrote: post #104

Earlier quoted context omitted.

In Europe, fosil fuel engines are already 2-4 times more expensive to run than electrics. In 11 years, which is the average age of a car in Europe, the majority of private vehicles will switch naturally for purely economic reasons. In 20 years, the same will be true for busses, trucks & tractors. And it will be driven solely by better economics.

And what do you get by replacing one ICE vehicle in Europe with an electric one? You get two cars. A shiny new electric one running in (Central) Europe, and that same old stinky ICE one running in Eastern Europe, Asia or Africa. The poorer countries will enjoy an influx and thus price decrease of valuable cars and happily drive them for decades to come. The problem of course is that the planet doesn't care. Europe go…

When you switch a 11 year ICE car with an electric, yes, you would generate a 11 year-old ICE car. If priced low enough, somebody will pick it up and use it for a few years, since the purchase price, compared to a new electric car, is lower than the (worse fuel economy + higher maintenance costs) figure.

But, unless gasoline and diesel drastically drop in price, you are running towards an economic wall, since it's exactly people from Africa and former soviet territories that are the most sensitive to fuel economy and high maintenance costs. Meanwhile, electrics drastically drop in price, since they simpler and cheaper to produce.

The extra few years European cars will see in Africa is just the long tail of the ICE car in Europe, not some fundamental shift. If those would not be available, Africans would purchase cheap new Chinese ICE or other low cost brands. A visit to Eastern Europe will convince you that some 50% of cars are newly purchased cheap brands like Dacia-Renault, Mitsubishi Colt, Chevrolet Spark, often stripped down versions made specifically for these markets and priced at something like 10.000€.

These will have an even lower life expectancy than the typical 20-40.000€ western car, and will be in need for replacing.

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

#187

Post by robbrown451 »

dekhn wrote: post #155
anamax wrote: post #120

Earlier quoted context omitted.

The University of California schools think of themselves as independent entities, independent entities that just happened to all pick the same school colors. berkeley.edu (where "University of CA" is a subtitle), ucla.edu, ucdavis.edu, etc.

No, this isn't the case at all. I attended UCSC (ucsc.edu), and then UCSF (ucsf.edu) and was a postdoc at UCB (berkeley.edu). They are fairly integrated in a lot of ways. The term itself "Berkeley" can be used in context so that people can tell you mean the University, not the city. That's rarer for the other schools. Also, Berkeley was the first real UC campus. I think Berkeley has its own bare domain because their…

They are more separate than University of Cincinnati is. If someone in California asks what college you go to, you don't say "UC"....you say "UC Berkeley" (or "Cal") or "UCLA" or the like. But you simply say "UC" if you are in Ohio and go to Univ of Cincinnati.

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

#188

Post by MertsA »

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…

It does convert CO2 into "fuel" but the ISS just vents it into space. The utility for the ISS is getting the O2 back and being able to ship up water and use it for atmospheric regulation as well.

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

#189

Post by letitbeirie »

fho wrote: post #111
gpm wrote: post #85

Earlier quoted context omitted.

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.

> 1kg of CO2/day which is crazy low if you put it in perspective and see that (gas powered) cars release about 0.2 kg of CO2 ... per kilometer.

Takes me all damn day to run a 5K so that checks out.
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