Lab Makes Jet Fuel From CO2


A team of scientists at Oxford University has made jet fuel from carbon dioxide in the lab and there is some optimism that it could be commercialized. A report in Nature Communications said the team essentially reverse engineered the chemical reactions that turn fossil fuels into CO2, which is considered the most important greenhouse gas. “Climate change is accelerating, and we have huge carbon dioxide emissions,” Tiancun Xiao, a senior research fellow at Oxford’s Department of Chemistry and an author on the paper, told the publication. “The infrastructure of hydrocarbon fuels is already there. This process could help relieve climate change and use the current carbon infrastructure for sustainable development.”

The process does require a large amount of heat, which could come from renewable electricity. It involves heating citric acid, hydrogen, and a catalyst made of iron, manganese, and potassium and adding them to the carbon dioxide to produce liquid fuel. The Oxford team’s idea is to build the jet fuel plants at big producers of CO2 such as steel mills. One of the big advantages of the process is that the metals used as a catalyst to make the fuel are cheap and plentiful.

Russ Niles
Russ Niles is Editor-in-Chief of AVweb. He has been a pilot for 30 years and joined AVweb 22 years ago. He and his wife Marni live in southern British Columbia where they also operate a small winery.

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  1. Looking ahead. If you burn the new fuel, wouldn’t it still release CO2 gases that cause pollution? It looks like you would be back where you started from!

    • No, in theory this would be CO2 neutral since the the carbon released was previously absorbed. The net CO2 generation would be zero (assuming that the process to formulate the fuel does not require CO2 generation, which the article indicates is plausible if renewable sources are used to provide the energy required to formulate the fuel).

    • It is carbon removed from the atmosphere, then burned in aircraft, and then placed back in atmosphere with zero increase in carbon due to aviation. Currently, fossil fuel releases (formerly sequestered in the ground) CO2 to a net increase in atmospheric CO2.

      • If you ignore the fact that it takes huge amounts of energy to collect, store, and then process CO2 into a usable fuel, ONLY then can you claim “zero increase”. The end product will probably mean that natural gas power plants will need to be built to support the required new energy demand for such an endeavor…

        • Unless the energy required could be obtained from non-CO2 generating sources. I know everyone on this forum loves to be critical of renewable energy, but the world is moving in that direction.

          The last paragraph in the article says:

          “The Oxford team’s idea is to build the jet fuel plants at big producers of CO2 such as steel mills.”

          Steel mills and other industrial plants generate lots of waste heat which could also be recovered for this process. Even if this process cannot obtain 100% net-zero carbon, it’s still shows promise for a substantial reduction in total CO2.

          I’ll leave it to the researchers and scientists that are much smarter than the armchair quarterbacks on the internet to figure it out.

          • Daniel, I’m curious why you think it needs to be “figured out”? The chemistry was done a very long time ago. No one is critical of renewable energy since it’s old news; the resistance is to salesmen selling us such old ideas as being brilliant or untried.

    • The point of this (and other similar efforts) is to close the loop on CO2 emissions. In effect it’s taking CO2 out of the atmosphere and burning it again. It doesn’t remove CO2, but such a closed-loop allows liquid-fueled engines (airplanes, cars) that does not add any more CO2 to the atmosphere.

      Right now, burning oil takes carbon that was formerly trapped underground and releases it into the air as CO2. It’s a one-way process. As the CO2 builds up things happen to the climate that are generally bad for us humans. Those are the facts. Politics enter when deciding what to do about it. From left the right the solutions are either stop burning everything while going to back to bicycles and horses, to denying the problem even exists while building fireproof houses on stilts.

      Another solution is to stop adding more CO2 to the atmosphere. The basic formula of hydrocarbons (HxCx) plus oxygen (O2) equals heat (power, energy) plus water (H2O) and carbon-dioxide (CO2) is reversible. Take heat (energy), water, and CO2 and you can (theoretically) make hydrocarbons (HxCx) again.

      Many scientists are working towards that end, trying to find ways to convert CO2 back into fuel. Some are genetically modifying plants or bacterium to convert CO2 into alchohol-like precursors to fuel. They use the energy in sunlight.

      Others, like the study above, are working on a more industrial process. This is the first I’ve read about that goes straight to a jet-fuel like substance which is why it’s newsworthy.

      Two big hurdles remain:
      1) Is it scalable? Can this process be (affordably) scaled up to make millions of barrels of oil?
      2) What is the source of energy to make this happen?

      The process only helps reduce CO2 if the source of energy does not come from burning oil, otherwise it’s worse than just burning more oil in the first place (kind of like current ethanol production). If the source of heat can come from non-oil sources (nuclear, hydroelectric, wind, or solar-panels or -mirrors) then the result is ‘clean’ oil – whatever CO2 that results from burning it goes right back into make more of it; no additional CO2 is added to the atmosphere.

  2. Hey, once you ignore the the law of conservation of energy (or have several strong drinks) this process sounds pretty good.

    • Not really, since the CO2 removed from the atmosphere could prevent as yet unburnt carbon from being released and combined with renewable energy without burning yet more carbon for the catalyst would not violate the law of conservation of energy

      • Being a chemist, I would need to see your equations for the process. Personal experience is that I would ballpark that it will take at least 3 times the energy to collect and synthesize.

    • Actually, scientists are also working on improving photosynthesis. As I recall, plants are only about 1% efficient at converting sunlight to stuff. I seem to recall a recent experiment that achieved 10% efficiency at photosynthetic chemical conversion of CO2 to alcohol-type liquids.

  3. Interesting, but there really isn’t anything new or revolutionary in this process. A good chemist, given the right catalysts and a ready source of hydrogen could convert CO2 into a polyester leisure suit, though God knows why you would want to. Bad humor aside, Arhtur is right, that this process requires more energy to react CO2 back to jet fuel (or any other hydrocarbon based fuel) than you will get out of it. And yes, the main idea here is to limit the amount of new carbon being dumped into the atmosphere, so the energy issue takes a back seat. I will give credit to the development team that they are at least targeting large point sources of CO2 emissions that are major contributors to total atmospheric carbon. The “big three” producers of atmospheric carbon are the steel and cement industries and electric power generation. Each produces more CO2 emissions than all the jet and avgas burning aircraft in the world do. Reducing their emissions is going to net far more carbon reductions that converting jet aircraft to burning hydrogen or running on batteries.

    My biggest problem with this process is that it requires two major ingredients that are problematical; a ready source of hydrogen and a large supply of electricity. Yes, we can provide the electricity from renewable sources, but they require massive amounts of land and have limited production reliability. Nuclear power is a much more reliable method of generating constant power with zero carbon emissions. I don’t want to get into the nuclear debate, so for now, I will concentrate on the other necessary ingredient – hydrogen. Currently, our only sources of free hydrogen are from electrolysis of water or chemical conversion of methane, which also produces CO2. Nature has a much simpler method for recovering CO2 that requires very little energy (other than sunlight) and no catalysts. Exxon Mobil and several universities have conducted a lot of research into growing algae from the CO2 in industrial flue gasses. The algae can then be harvested for its oil content that is easily refined into jet (naphtha) level fuels. I applaud the Oxford’s team for conducting the research, but I would be much more willing to support plant-based methods that take far fewer resources to begin with.

  4. Those of you looking for the equations of the process, click on the link in the second sentence ( A “report in Nature Communications” s….. ). You can download the complete research paper.

  5. I think we should go back to that idea of having a small propeller driven generator l;ike those seen on the belly of old piston engine airplanes. We could hook it up to the battery, take the engine out and replace it with a motor and … WHALA … no CO2. Just because something is chemically possible doesn’t mean it’s economically or physically practical but … maybe these people could figure a way to convert carbon MONoxide to something usable? I STILL wanna know WHY the CO2 levels of the earth were higher when dinosaurs were clomping around the planet were higher. Maybe there were too many SUV’s around ?

    • “I STILL wanna know WHY the CO2 levels of the earth were higher when dinosaurs were clomping around the planet”

      A lot of that CO2 was consumed by plants that got buried and became today’s oil deposits. So we’re just releasing CO2 from millions of years ago back into the atmosphere.

      And, yes, there was life on earth back then. But sea levels were about 100 feet higher back then, too. Which would put almost all of Florida under water, just for starters.

      • The cool thing is that the atmosphere has not warmed. People need to figure out a new theory as to why surface temperatures are rising while the atmosphere has not. Logic shows that co2 May be correlated but it’s not causative.

        • That’s an incorrect statement. Multiple measurements show air temperature close to the ground and the average temperature of the lower troposphere have both increased, along with sea water temperatures.

          • All readings in the atmosphere (the real atmosphere; not the few feet just above the ground)have not risen above the margin of error the devices taking the readings. Again, sea water temperatures are up but the warming did not occur first in the atmosphere. THAT is neat and that needs investigating. The co2 theory needs to be dropped and a new theory made to address this reality.

          • I’m not sure what you define as “real atmosphere” (is there a fake one?). But the troposphere (the part we all live and breathe in) extends from the surface to about 10-11 miles above it. And the temp of the trop (not just the part a few feet above the ground) has been rising on average. And more so than any “margin of error”.

            Most CO2 is in the troposphere which is where most of the heat is trapped. As a result the stratosphere just above it has cooled. Skeptics and deniers have seized upon this as ‘proof’ that the overall atmosphere hasn’t changed at all. This is like arguing that one wasn’t speeding at 100mph because passing a parked car means the overall average was below the 55 limit.

      • What’s going to happen when ‘ol Sol turns into a red dwarf and incinerates the earth ?? A lot of good all these CO2 conversion schemes are going to do then. As to the shorter term issue, if we get rid of all the CO2, what’re the trees going to eat ? And why were CO2 levels SO much higher (from ice core samples 10,000 years old) back when? I have an idea … let’s just invent a carbon tax and that’ll solve everything. Carbon credits are nothing more than rearranging the deck chairs on the Titanic.

        Everybody wants to deal with CO2 reduction and totally ignores the fact that we may have passed the point of having too many humans on the planet. Each and every human has a minimal necessary impact on the planet that is measurable. Some lucky humans generate more in all sorts of ways. When are we going to limit the population instead of letting everyone do what they want and then just try to reduce CO2 after the fact. We pilots deal with weight and balance … there’s a larger macro situation with the planet. Anthropogenic climate change is largely caused by burning coal. The burning of coal is responsible for 46% of carbon dioxide emissions worldwide and accounts for 72% of total greenhouse gas (GHG) emissions from the electricity sector. Meanwhile, everyone wants to switch to electric powered airplanes which run on … electricity which is largely generated by coal

  6. I was working on this type on system with my father before he died 5 years ago. We thought of a collection system along highways to filter and collect the CO2. The problem is; Hydrogen was needed for the process and it didn’t seem like a good idea to have it stored along busy highways with high speed crashes close by.

    • Richard, unfortunately any process that tries to chemically convert CO2 into a useable fuel requires hydrogen. Even living plants that sequester the carbon in the form of the plant’s structure needs hydrogen. The difference with plants is that they use sunlight to split water into hydrogen and oxygen – the hydrogen combines with the carbon and the oxygen gets released into the air. It’s a little more complex than that, but that’s the basic idea. However, there is a relatively simple method of pulling CO2 out of the air, which has been used in the oil production industry for generations. It involves bubbling the CO2 rich gas through a solution of phosphate based chemicals – usually monoammonium phosphate (MAP) or diammonium phosphate (DAP). The MAP or DAP adsorbs the CO2 onto its chemical structure. The solution is then heated and the CO2 comes off to be captured. It is a fairly efficient process that does not require a lot of excess energy.

      What you do with the CO2 is then up to you. Some power generation stations that use coal are now installing these systems to trap most of their flue gas CO2 and then injecting it deep underground in depleted oil or gas formations. Over time, the CO2 will react to carbonate based materials that permanently lock the carbon away. The famed White Cliffs of Dover in England are basically CO2 that was converted by marine life into calcium carbonate (i.e. Limestone) eons ago when Kirk W’s sea levels were much higher than today. A couple of companies have taken your idea and are proposing to install these CO2 trapping plants along major highways. The CO2 could then be easily compressed and pipelined to a central collection plant where the hydrogen is safely used, away from car crashes and other highway mayhem. Keep working on it, you may still have a good idea.

  7. Kirk, you cannot use low level atmosphere temps! Low level is susceptible to too many influences besides co2. Trees, lack of trees, asphalt, water vapor, winds, proximity to water, etc, etc. The air temp just above the ground is literally useless as far as the theory goes.

    • Please re-read my post. I’m talking about the entire troposphere, not just the ground level measurements.

      • Garbage in garbage out. You have to throw out all the lower levels BECAUSE of the large effects of other land based influences. You are not measuring the effect of co2 way down low. That is why you are confused.