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Fuel out of thin air: CO2 capture from air and conversion to methanol (2020)
- the__alchemist 4y ago> Additionally, methanol, which is a liquid with a boiling point of 64.7 °C, is a superior fuel for internal combustion engines and fuel cells, as well as a convenient high density liquid hydrogen carrier. Methanol can be converted to ethylene and propylene through the MTO (methanol to olefins) process. Hence, the production of renewable methanol and the associated methanol economy holds significant potential to replace current fossil fuel-based economies. No! Quite toxic. Don't want that around consumer-facing products. (Any more than in the engine coolant and wiper fluid it's already in)
- zbrozek 4y agoI'd love to have a small scale synthesis setup that I can use to store my excess production of solar electricity in the summer. I waste many MWh curtailing solar production. Some napkin math suggests I throw away enough photovoltaic energy in one summer season to more than cover all of my pickup truck driving.
- maria2 4y agoWhy don't you get an electric car and battery instead?
- AtlasBarfed 4y agoThe low temp requirements look promising, but wake me up when the cost of the system at scale is known. Obviously things like long haul aviation need synthfuels, but I wouldn't hold my breath that this will be the magic bullet for keeping the ICE relevant in the next century.
- tuatoru 4y agoMethanol is a feedstock for lots of industrial chemicals too.
- pfdietz 4y agoMethanol can be turned into gasoline by the ExxonMobil MTG process. https://www.exxonmobilchemical.com/en/catalysts-and-technology-licensing/synthetic-fuels https://www.exxonmobilchemical.com/en/catalysts-and-technolo...
- PaulHoule 4y agoThis is not really new, lots of people are writing papers on different paths to this. There was a huge interest in synthesizing motor fuels from coal or natural gas up to 1980, it makes for depressing reading because the Fischer-Trospch chemistry for building up hydrocarbons from hydrogen and carbon monoxide has awful economics. For anything else people would be happy that iron works as a catalyst but they scoured the rest of the periodic table looking for something better and didn’t find it. You have to run the reaction at low temperatures otherwise you get nothing but methane, but under those conditions reactions that build up and break down hydrocarbons are closely balanced so you have a huge machine which makes a trickle of fuel so the capital costs are high. Looking at the history you’d think somebody would tell the airplane engineers that they should just go clean sheet and figure out how to fuel airplanes with hydrogen or methane but they are so used to being coddled (like that time the FCC couldn’t make them upgrade their broken altimeters or how they are just barely starting to remove lead from GA fuel after all these years) that they are sending chemical engineers on what’s been a lost cause for more than a century.
- rootusrootus 4y ago
- eganist 4y ago> When air was bubbled through potassium hydroxide dissolved in ethylene glycol and the CO2-loaded solution subsequently hydrogenated in the presence of H2 and a metal catalyst, complete conversion to methanol was observed at 140 °C. Am I missing something? Isn't the need for hydrogen gas here a constraint? It's either gonna be refined (steam reforming) or split from water.
- pfdietz 4y agoThis scheme is combining synfuel production with CO2 capture, which is kind of cute. The hydrogen is serving two functions: it makes methanol, but it also regenerates the alkaline CO2 capture solution.
- tuatoru 4y agoH2 is necessary, yes. It can be provided by electrolysis of water, air captured if necessary.
- eganist 4y agoYeah that feels like it defeats the point. Not that I know the math, but it feels like there's a potential for it to be a net contributor of carbon emissions by encouraging more steam reforming of cng (and thus more cng pumping) or through power consumed to split water—power which invariably will come from dirty sources until we've done a better job moving away from dirty power. I'd be curious to see someone graph out where this transitions from being carbon positive to being carbon negative (or vice versa)
- PaulHoule 4y agoNo, e-Fuels like this are a way to make fuel from carbon free sources and that means splitting water to make hydrogen and sucking CO2 out of the air. The navy is interested in making e-fuels from electricity on nuclear aircraft carriers since a gallon of jet fuel delivered to an aircraft carrier costs a lot more than a gallon of jet fuel delivered to a civilian airport and the aircraft carrier has to slow down a lot so a tanker it refuels from can catch up with it.
- yathern 4y agoNote: This is from 2020
- mentos 4y agoFrom a very high level I wonder if we could use nuclear power to drive a CO2 capture mechanism to ‘make up’ for all the time spent burning fossil fuels instead of nuclear?
- dotnet00 4y agoIf we were willing to significantly overbuild nuclear power production capability yes, but from what I understand with current carbon capture efficiency it's more effective to have that nuclear power directly offset current energy consumption instead.
- themoonisachees 4y agoFrom a logical standpoint carbon capture is a scam [0]. The argument is "if you don't have spare energy, why are you spending it on carbon capture? And if you have spare energy (you don't), why not spend the money you usee to build the over capacity to bring clean energy somewhere else?" That is all assuming your entire power grid is 100% clean (it isn't) because otherwise you fall in case 0 where you spend energy that could be spent on offsetting non-clean energy usage. [0] https://youtu.be/nJslrTT-Yhc https://youtu.be/nJslrTT-Yhc
- pfdietz 4y agoCarbon capture is not a scam, but it is premature. It could make sense once fossil fuels are abolished, or at least we stop using them at fixed locations where CO2 can be captured without releasing it to the atmosphere.
- kbenson 4y agoIt depends on the speed of capture. If you can capture faster than conversion reduces, and there are time constraints that mean reducing carbon now is better than later, then it can make sense. It's the same as whether you should reduce expenses or increase income. Both yield a net increase, but there are variables than can make one better than the other in the short term. Whichever yields the most benefit for the effort is probably the best one, or if one has a time constraints and the other doesn't, that might be the best one to focus on.
- gumby 4y agoI've seen a bunch of these over the years; still waiting for one that will get traction. The changing cost of oil (mainly making externalities fiscally concrete) may change the equation. The most interesting I ever ran across was people doing artificial photosynthesis to produce H2 and combustable oil, e.g. Nate Lewis' group at Cal Tech. Same problem: contemporary economics. I'm glad people are still working on these problems.
- deleted 4y ago[deleted]
- nix23 4y ago>still waiting for one that will get traction. There is one, got traction since millions of years..it's called trees: https://www.britannica.com/science/methanol https://www.britannica.com/science/methanol >>wood alcohol, or wood spirit
- greenyoda 4y agoAlso, this Wikipedia article specifically discusses the use of methanol as a fuel: https://en.wikipedia.org/wiki/Methanol_fuel https://en.wikipedia.org/wiki/Methanol_fuel
- Archelaos 4y agoOr wood gas. At the end of WW2 there were about 500,000 vehicles with wood gas generators in use in Germany to make up for the lack of other fuels.[1] But under today's conditions, this possibility does not seem to make economic sense. [1] See: https://en.wikipedia.org/wiki/Wood_gas https://en.wikipedia.org/wiki/Wood_gas
- nix23 4y agoNora-Korea has still wood gas generators attached to cars:
- gumby 4y ago
- deleted 4y ago[deleted]
- pfdietz 4y agoA problem with ideas like these is that they have to be cheaper than burning fossil fuels and then capturing and sequestering CO2 to compensate. Both schemes capture CO2, so that part of the cost cancels out. Sequestering CO2 once you have it shouldn't be very expensive, especially if it can be used to stimulate more petroleum production. If you're going to capture CO2 from the atmosphere it may be very favorable to do it at high latitude, where air is colder. I wonder if this could be sold to Russia as a way for them to make money in a post-fossil fuel world. https://www.cell.com/iscience/fulltext/S2589-0042(22)01836-3 https://www.cell.com/iscience/fulltext/S2589-0042(22)01836-3
- bryanlarsen 4y agoCapturing the CO2 is the most expensive part of the process. Pumping fossil fuels out of the ground and then capturing and storing the resulting carbon is likely going to be more expensive then capturing carbon, synthesizing the fuel and burning the synthetic fuel. But in both scenarios capturing the carbon is the dominating cost so they're always going to be roughly comparable.
- brutusborn 4y agoWhy is fossil fuel carbon capture likely to be more expensive than atmospheric capture? The CO2 can be captured in a concentrated form directly from an exhaust so surely it has to be more efficient and thus less expensive.
- joe_the_user 4y agoWho says the fossil fuel carbon will be captured? It's certainly not now and who says carbon capture is ever going to be enforced? The only hope I have is that solar energy becomes so cheap that it can be profitably used to produce synfuel and so drive petroleum from the market. Actual regulation would be better but that seems as far as ever.
- brutusborn 4y agoWho says solar energy can possibly get that cheap? If you are skeptical of carbon capture being mandated by regulations then I think you should be equally if not more skeptical of the market restructuring itself so renewable energy based petroleum substitution becomes a reality spontaneously. It makes no sense economically or politically.
- the_third_wave 4y agoUsing such a process on plain air is not likely to ever be economically feasible as air only contains a tiny amount of CO₂, around 400 parts per million. If you want to run such a process run it on the exhaust stack of a gas-fired power plant since that contains a good amount of CO₂. Of course this only makes sense if the capture takes less energy than the power plant produces which can not be the case since it would violate the second law of thermodynamics [1]. [1] https://www.britannica.com/science/second-law-of-thermodynamics https://www.britannica.com/science/second-law-of-thermodynam...
- brutusborn 4y agoCan you please explain why it violates the second law of thermodynamics? I thought the 2nd law would only apply if you are reversing the reaction, i.e. CO2 -> C + O2 , whereas we are simply moving the CO2 underground. To me the critical measure would be how much energy the CO2 needs to be compressed to get it underground.
- andrewmutz 4y agoWell the good news is that every year that 400ppm goes up
- sbierwagen 4y ago>violate the second law of thermodynamics This is directionally correct, in that coal emissions sequestration is unlikely to be economical, but with two caveats: 1) Most coals are not actually pure carbon, they do contain a small percentage of hydrogen. If you don't capture the resulting water vapor† then that gives you some combustion energy for free. 2) If you had to spend energy to split the carbon off CO2 and sequester the carbon, then yes, it would be a pointless round trip. Which is why most "clean coal" schemes just compress the CO2 and sequester it underground. --- †: Water vapor is itself a powerful greenhouse gas, but it varies between 4,000 and 25,000 ppm, so clean coal, which is intended to be a short term stopgap measure operated only for a few decades until the global PV solar infrastructure is built out, shouldn't have time to affect global gas balances.
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- bparsons 4y agoThere are a million ways to produce smaller amounts of energy from larger amounts of grid energy. This isn't really useful.
- Gibbon1 4y agoYeah it's like the old snark about investing. It's being easy to make a million dollars. Just start with two million dollars. The gross thing about this stuff is it's predicated on the average person not being able to do the engineering and accounting calculations to realize it's all lies.
- 0xf00ff00f 4y agoDoes anyone know whatever happened to Prometheus Fuels?
- mgiampapa 4y agoStill burning money, but looking for things where green premiums can be paid like for woke Zero Net Carbon aircraft.
- tjkrusinski 4y agoIt was anecdotal, but I met someone who worked with folks who worked there, there's a lot of smoke and mirrors and they don't really have what they say they have. Unfortunate as it looked really promising.
- DennisP 4y agoAs in, it flat doesn't work, or it's just not economical enough at current energy prices?
- tjkrusinski 4y agoThe former. They're working to eliminate the need for an energy intensive distillation process and they haven't been able to get it to do what they've promised. They say they have a carbon nano-tube filter that can separate water and ethanol but no one's seen it work at high efficiency. https://en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch_process https://en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch_proces...
- acidburnNSA 4y agoQuick summary: "Given sources of Carbon and Hydrogen plus massive energy inputs, you can synthesize hydrocarbons!" I feel like the headlines always try to pretend you're getting energy out of the CO₂ rather than putting energy into a hydrocarbon energy storage chemical. Question of course is economics of converting some (hopefully clean-ish) energy into stored hydrocarbon chemical bond energy and then combusting it in a vehicle vs. just digging up hydrocarbons and combusting them.
- ChuckMcM 4y agoIt is an answer for the complaint "but solar doesn't work at night" and "transmitting energy over long distances is inefficient" You see you could cover enough desert in Nevada with enough solar panels to provide 100% of the current electricity use of the United States. But you couldn't transmit it over the current grid to the rest of the country and it would "turn off" every night. So stupid right? Except maybe you are using that energy to create natural gas and you're shipping natural gas around through pipelines to standard gas electric power plants. The math works, and the BLM has enough land (caveat the endangered tortoises) and so it is a "technically possible" solution to carbon neutral energy (you're taking CO2 out of the air and then returning it when you burn the natural gas). This also works with fission power plants as the source of energy, and really shines with fusion power plants (fewer externalized issues like waste management).
- nine_k 4y agoIn other words, given a solar or nuclear plant near a chemical / metallurgy plant, you can also produce some liquid fuels.
- janef0421 4y agoOr, if you're concerned with the climate impact of using fossil fuels, you can consider the economics of shifting to a technology that cab use the energy more directly; I.e, replacing aviation with electric railways.
- drallison 4y agoAmen. Fuel out of thin air: CO2 capture from air and converted to methanol takes way more energy than can be recovered from the created fuel.
- Animats 4y agoBrought to you by the Loker Hydrocarbon Research Institute. Mission statement: "The final solution to the hydrocarbon shortage will come only when mankind can produce unlimited cheap energy as with the promise of safer atomic energy and other alternate sources. With abundant cheap energy, hydrogen can be produced from sea water and then combined with carbon dioxide to produce hydrocarbons. In the meantime, however, it is essential that solutions be found that are feasible within the framework of our existing technological base. The Loker Hydrocarbon Research Institute is at the forefront of this effort."
- rqtwteye 4y agoWith enough energy input you can do a lot of interesting things. Question is where you get the energy from.
- jillesvangurp 4y agoAnd a related question is whether there are more interesting/efficient things you could do with that energy. It's a question that relates to the laws of thermodynamics as well which dictate that the conversion between different forms of energy has some theoretical upper limits in terms of efficiencies and those inefficiencies multiply if you have a series of such conversions of e.g. solar power to carbo hydrates to mechanical energy or electrical energy. The longer that chain, the worse it gets. You are better off charging a battery and using the stored energy directly. Almost no losses that way. It's the most efficient way to use energy for a lot of things. There is a market for synthetic fuels of course but it is going to have to be a market that is willing to pay at least 3-5x the energy cost they would have if they were able to use electricity directly. A good example is long haul aviation. Batteries don't work for that (too heavy). Shipping might be another one.
- ggm 4y agoThat would be growing plants to convert CO2 to carbohydrates and sugars, sprouting them to uplift more carbohydrates to sugars, fermenting them and extracting the ethanol? OK. Wrong -ol. So, do it wood chips..