From the MASSACHUSETTS INSTITUTE OF TECHNOLOGY
MIT-developed method converts carbon dioxide into useful compounds.
CAMBRIDGE, Mass. — MIT researchers have developed a new system that could potentially be used for converting power plant emissions of carbon dioxide into useful fuels for cars, trucks, and planes, as well as into chemical feedstocks for a wide variety of products.
The new membrane-based system was developed by MIT postdoc Xiao-Yu Wu and Ahmed Ghoniem, the Ronald C. Crane Professor of Mechanical Engineering, and is described in a paper in the journal ChemSusChem. The membrane, made of a compound of lanthanum, calcium, and iron oxide, allows oxygen from a stream of carbon dioxide to migrate through to the other side, leaving carbon monoxide behind. Other compounds, known as mixed ionic electronic conductors, are also under consideration in their lab for use in multiple applications including oxygen and hydrogen production.
Carbon monoxide produced during this process can be used as a fuel by itself or combined with hydrogen and/or water to make many other liquid hydrocarbon fuels as well as chemicals including methanol (used as an automotive fuel), syngas, and so on. Ghoniem’s lab is exploring some of these options. This process could become part of the suite of technologies known as carbon capture, utilization, and storage, or CCUS, which if applied to electicity production could reduce the impact of fossil fuel use on global warming.
The membrane, with a structure known as perovskite, is “100 percent selective for oxygen,” allowing only those atoms to pass, Wu explains. The separation is driven by temperatures of up to 990 degrees Celsius, and the key to making the process work is to keep the oxygen that separates from carbon dioxide flowing through the membrane until it reaches the other side. This could be done by creating a vacuum on side of the membrane opposite the carbon dioxide stream, but that would require a lot of energy to maintain.
In place of a vacuum, the researchers use a stream of fuel such as hydrogen or methane. These materials are so readily oxidized that they will actually draw the oxygen atoms through the membrane without requiring a pressure difference. The membrane also prevents the oxygen from migrating back and recombining with the carbon monoxide, to form carbon dioxide all over again. Ultimately, and depending on the application, a combination of some vaccum and some fuel can be used to reduce the energy required to drive the process and produce a useful product.
The energy input needed to keep the process going, Wu says, is heat, which could be provided by solar energy or by waste heat, some of which could come from the power plant itself and some from other sources. Essentially, the process makes it possible to store that heat in chemical form, for use whenever it’s needed. Chemical energy storage has very high energy density — the amount of energy stored for a given weight of material — as compared to many other storage forms.
At this point, Wu says, he and Ghoniem have demonstrated that the process works. Ongoing research is examining how to increase the oxygen flow rates across the membrane, perhaps by changing the material used to build the membrane, changing the geometry of the surfaces, or adding catalyst materials on the surfaces. The researchers are also working on integrating the membrane into working reactors and coupling the reactor with the fuel production system. They are examining how this method could be scaled up and how it compares to other approaches to capturing and converting carbon dioxide emissions, in terms of both costs and effects on overall power plant operations.
In a natural gas power plant that Ghoniem’s group and others have worked on previously, Wu says the incoming natural gas could be split into two streams, one that would be burned to generate electricity while producing a pure stream of carbon dioxide, while the other stream would go to the fuel side of the new membrane system, providing the oxygen-reacting fuel source. That stream would produce a second output from the plant, a mixture of hydrogen and carbon monoxide known as syngas, which is a widely used industrial fuel and feedstock. The syngas can also be added to the existing natural gas distribution network.
The method may thus not only cut greenhouse emissions; it could also produce another potential revenue stream to help defray its costs.
The process can work with any level of carbon dioxide concentration, Wu says — they have tested it all the way from 2 percent to 99 percent — but the higher the concentration, the more efficient the process is. So, it is well-suited to the concentrated output stream from conventional fossil-fuel-burning power plants or those designed for carbon capture such as oxy-combustion plants.
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The research was funded by Shell Oil and the King Abdullah University of Science and Technology.
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From the article: “which if applied to electicity production could reduce the impact of fossil fuel use on global warming.”
What impact?
Don’t I recall some similar process was described last year- adding CO2 to seawater, introduce a LOT of electricity, and Voila!… jet fuel.
Actually might make some sense for a nuclear-powered aircraft carrier…
If this process runs at 990 Celsius (1814 F), this is much hotter than the exit temperatures of most industrial boilers or gas turbines. Why would anyone go through the expense of heating flue gas to such high temperatures (and finding metallurgy that can withstand such temperatures) to convert CO2 back to carbon monoxide (CO) and oxygen?
The article states that a “fuel” stream of hydrogen or methane could be used to strip one of the oxygen atoms off a CO2 molecule. If hydrogen is used, the result is carbon monoxide and steam. If methane is used, depending on the ratios, one could obtain carbon monoxide, hydrogen, steam, and/or formaldehyde, all of which would have a lower energy content than the original methane. In either case, the energy content of the fuel stream is reduced, in order to convert harmless carbon dioxide into toxic carbon monoxide. Why?
The article states that this process could be used to make “synthesis gas”, which is usually a mixture of hydrogen and carbon monoxide. While carbon monoxide can be useful as an intermediate gas in the production of some monomers for plastics manufacturing, the most prevalent production of synthesis gas comes from a well-known catalytic process called steam-methane reforming, which is used to produce hydrogen and releases lots of heat.
The reaction for steam-methane reforming is
CH4 + H2O –> CO + 3 H2 + heat
The synthesis-gas stream is then cooled and sent to a water-shift reactor, where the CO reacts with steam to produce CO2 and an additional molecule of hydrogen.
CO + H2O –> CO2 + H2 + heat
This mixture is then separated into high-purity hydrogen and CO2 using a molecular sieve and “pressure swing adsorption”.
The steam-methane reforming process is primarily used to generate hydrogen, but it also releases lots of heat, which is usually used to generate steam from water, which can then be used to run turbines. Carbon dioxide is the low-energy product of this reaction, so that trying to run the water-shift reaction backwards, which is what the MIT team is trying to do, will require a huge energy input.
There are much more efficient ways of removing CO2 from the atmosphere, which use solar energy to power the process. They’re called trees.
Q. How does a scientist turn CO2 into 1 MJ of useful hydrocarbon energy?
A. Start with 2 MJ of useful hydrocarbon energy and a grant supported research project.
how do you create $1 million in renewable energy? start with $2. million in taxpayer money.
The $2 million is for the capital cost. You need another $1 million annual operating cost and another $1 million a year for maintenance.
And add another $10 million in PR fees, press conferences and legal fees. The legal fees are needed to sue anyone who disagrees with either the efficacy of the process or the need for it.
OT, speaking of batteries for backing-up wind intermittency…
https://www.wind-watch.org/news/2017/11/12/wind-power-backup-and-storage-batteries-explode-into-flames-and-send-a-toxic-cloud-over-the-city-of-brussels/
Will not be the last of those incidents !!!
“Let’s hope that at least this one is fake news, otherwise it would mean that these batteries are just chemical bombs ready to explode at any time.”
Well, batteries ARE chemical bombs ready to explode at any time. Just ask apple or samsung. A small one will just “pop” with less damage than a firecracker. A big one will make enough smoke to worry a neighborhood.
Another perpetual motion scheme.
The basic fact is that it takes at least as much energy to break the bonds between the atoms as you get by combining them.
Assuming 100% efficiency you get a net gain of … zero.
In the real world, you will not get 100%.
It is no more than an attempt at the ‘ beautifying image photoshop’ of the oil industry’s grandees Shell Oil and the Saudi Arabia who financed this useless research.
This is a process for creating energy which is useless and very costly and wasteful…exactly what the Greens have been looking for.
These types of materials have been around a long time.
Materials-of-construction issues.
Mundane things like flanges and valves don’t work well at those temperatures.
Right 1814 F is above the ASME CODE for all pressure vessel construction materials . Even the most expensive high nickel alloys creep at this temperature
Superalloy? I don’t know what they’re rated at these days or if they are considered acceptable for a pressure vessel.
Many comments above about why this is a daft scheme.
Why are we not screaming at the scammer “scientist” and his “team” who must know (because they are scientists) that this is a scam yet still happy to pose for a picture, make PR releases and take the money to tell these lies?
Do schools not teach proper chemical thermodynamics anymore?
I can remember sitting doing piles of Gibbs free energy and enthalpy calculations when I was 17 and studying for my (now old fashioned) Scottish Higher and Sixth Year Chemistry exams. Great fun for those of us that ‘got it’, and many thanks to our teacher. His rigour and enhusiasm made sure that we really understood the meaning of ‘no free lunch’.
Wtf? I mean w the living f? That is so inconceivably stupid on so many levels it becomes difficult to even comment coherently. What do the actual scientists at MIT say about it over coffee? Do they roll about laughing or is anything carbon dioxide-related simply off limits under pain of expulsion. Whatever, any scientist/engineer beyond remedial freshman level would find that just buttock-clenchingly embarrassing.
Very nice idea. Lanthanum is an abundant rare earth metal and comparatively low cost, being produced as a byproduct of the heavy rare earth metals that are in greater demand.
But fellas, don’t go splitting the natural gas stream to run the carbon recovery! This kind of thinking arises because you are focusing on making the idea work at any cost and you are jumping on an opportunity provided by a a global warming crisis même that is now in decline. If this is plan A, I suggest passing the oxidizing problem to a new team for an innovative solution.
Think this thought experiment: you split the stream and burn half for power and the other half for making the synfuel from CO2. Then you use it to fuel the power plant! So now you don’t need the NG for the power plant, but you do need it to recover the CO2 from burning your synfuel! Have we got to this point in this society?
Don’t go knocking Lanthanum as if it was the pond scum of rare earths.
It is in fact one of the most useful ones.
We wouldn’t have all the modern fancy optical lenses that many of us take for granted if it wasn’t for the Lanthanum glasses.
G
Isn’t it fun when you are in the field of Physics and Engineering and you want some grant money to pursue your pet projects like membranes, etc. Just make it seem like it’s tied to global warming prevention and you can get all the money you want. Of course it doesn’t matter if the research is useless on it’s face for it’s intended purpose. This is irrelevant to how to work this gravy train.
I’ve got friends in research that do this all the time. If they skipped the global warming part of their grant request there wouldn’t be any money.
I wouldn’t doubt that it is feasible to extract butter from sh1t.
At enormous cost and involving enormously complex and energy intensive processes.
Myself, I am content to stick with butter made from cream skimmed from cow’s milk.
It seems that to be a scientist in most western countries you now have to be an activist and to have had all traces of common sense surgically removed.
Sad.
50 years ago MIT was a top rate school, today, not so much. Must say, though, that this is true of most schools today due to the extreme decline in the rigor of our educational system. Too many years of those who can, doing, and those who can’t, teaching.
An example of the depths that MIT has fallen to:
http://news.mit.edu/sites/mit.edu.newsoffice/files/images/2009/200908311113506360_0.jpg
I asked MIT whether this was a joke. I must presume it was, since they didn’t deny it.
My BS detector wrapped its needle around the peg when I read this article.
What a silly idea. Even MIT is going by the boards these days. Its president is a global warming LOON. So I guess I’m not surprised.
I think that you guys kind of miss the point. Who needs fuel in places that are heard to supply but have lots of energy? Hint: they operate aircraft carriers, tanks in the desert, and drones and aircraft that fly out of remote airstrips.
Hint: you’re better off splitting water and producing methanol with atmospheric CO2 using a nuclear reactor as the power source.
Aircraft carriers use nuclear power, as do many subs. Nuclear energised CO2+H2O= Fuel and other CH compounds is best way to do this. Already proven in pilot plants using several power sources, including mad hippy scientists in the New Mexico Desert. I costed this and produceda technical note with David MacKay’s help., BTW. Much more expensive than running an electric car charged from the same nuclear energy, but I didn’t include the battery depreciation.
There is already a low-cost method of doing this using solar power at low temperatures known as “photosynthesis”.
The research might not be a pure scam though, the membrane might be useful in other applications and the CO2 angle just a trick to get research money, I’ve used somewhat similar tricks to get funds for research myself (though in our case it was imaginary “diversity” and “gender” aspects). The funniest thing was that the people approving the appropriation were perfectly aware that the stuff was imaginary, but they had to play along with the nutty directives from the politicians.
Sugar cane is quite good at it and it readily converts into rum
Funded by Shell Oil, ergo evil
Thermodynamics. It’ll negate stuff like this every time.
In this house, we obey the laws of thermodynamics!
https://youtu.be/6vxHkAQRQUQ
Oh yeah sounds great! You just have to keep it at 1,000 deg C.
Ppbbbbbttttttt!
But CO is so darn toxic. I have a chemical reaction going on, on my property, that uses solar energy to convert greenhouse gases CO2 and H2O to celulose that can be used as a fuel and is far less toxic than CO.