The process could work on the gas at any concentrations, from power plant emissions to open air
Massachusetts Institute of Technology
A new way of removing carbon dioxide from a stream of air could provide a significant tool in the battle against climate change. The new system can work on the gas at virtually any concentration level, even down to the roughly 400 parts per million currently found in the atmosphere.
Most methods of removing carbon dioxide from a stream of gas require higher concentrations, such as those found in the flue emissions from fossil fuel-based power plants. A few variations have been developed that can work with the low concentrations found in air, but the new method is significantly less energy-intensive and expensive, the researchers say.
The technique, based on passing air through a stack of charged electrochemical plates, is described in a new paper in the journal Energy and Environmental Science, by MIT postdoc Sahag Voskian, who developed the work during his PhD, and T. Alan Hatton, the Ralph Landau Professor of Chemical Engineering.
The device is essentially a large, specialized battery that absorbs carbon dioxide from the air (or other gas stream) passing over its electrodes as it is being charged up, and then releases the gas as it is being discharged. In operation, the device would simply alternate between charging and discharging, with fresh air or feed gas being blown through the system during the charging cycle, and then the pure, concentrated carbon dioxide being blown out during the discharging.
As the battery charges, an electrochemical reaction takes place at the surface of each of a stack of electrodes. These are coated with a compound called polyanthraquinone, which is composited with carbon nanotubes. The electrodes have a natural affinity for carbon dioxide and readily react with its molecules in the airstream or feed gas, even when it is present at very low concentrations. The reverse reaction takes place when the battery is discharged — during which the device can provide part of the power needed for the whole system — and in the process ejects a stream of pure carbon dioxide. The whole system operates at room temperature and normal air pressure.
“The greatest advantage of this technology over most other carbon capture or carbon absorbing technologies is the binary nature of the adsorbent’s affinity to carbon dioxide,” explains Voskian. In other words, the electrode material, by its nature, “has either a high affinity or no affinity whatsoever,” depending on the battery’s state of charging or discharging. Other reactions used for carbon capture require intermediate chemical processing steps or the input of significant energy such as heat, or pressure differences.
“This binary affinity allows capture of carbon dioxide from any concentration, including 400 parts per million, and allows its release into any carrier stream, including 100 percent CO2,” Voskian says. That is, as any gas flows through the stack of these flat electrochemical cells, during the release step the captured carbon dioxide will be carried along with it. For example, if the desired end-product is pure carbon dioxide to be used in the carbonation of beverages, then a stream of the pure gas can be blown through the plates. The captured gas is then released from the plates and joins the stream.
In some soft-drink bottling plants, fossil fuel is burned to generate the carbon dioxide needed to give the drinks their fizz. Similarly, some farmers burn natural gas to produce carbon dioxide to feed their plants in greenhouses. The new system could eliminate that need for fossil fuels in these applications, and in the process actually be taking the greenhouse gas right out of the air, Voskian says. Alternatively, the pure carbon dioxide stream could be compressed and injected underground for long-term disposal, or even made into fuel through a series of chemical and electrochemical processes.
The process this system uses for capturing and releasing carbon dioxide “is revolutionary” he says. “All of this is at ambient conditions — there’s no need for thermal, pressure, or chemical input. It’s just these very thin sheets, with both surfaces active, that can be stacked in a box and connected to a source of electricity.”
“In my laboratories, we have been striving to develop new technologies to tackle a range of environmental issues that avoid the need for thermal energy sources, changes in system pressure, or addition of chemicals to complete the separation and release cycles,” Hatton says. “This carbon dioxide capture technology is a clear demonstration of the power of electrochemical approaches that require only small swings in voltage to drive the separations.”
In a working plant — for example, in a power plant where exhaust gas is being produced continuously — two sets of such stacks of the electrochemical cells could be set up side by side to operate in parallel, with flue gas being directed first at one set for carbon capture, then diverted to the second set while the first set goes into its discharge cycle. By alternating back and forth, the system could always be both capturing and discharging the gas. In the lab, the team has proven the system can withstand at least 7,000 charging-discharging cycles, with a 30 percent loss in efficiency over that time. The researchers estimate that they can readily improve that to 20,000 to 50,000 cycles.
The electrodes themselves can be manufactured by standard chemical processing methods. While today this is done in a laboratory setting, it can be adapted so that ultimately they could be made in large quantities through a roll-to-roll manufacturing process similar to a newspaper printing press, Voskian says. “We have developed very cost-effective techniques,” he says, estimating that it could be produced for something like tens of dollars per square meter of electrode.
Compared to other existing carbon capture technologies, this system is quite energy efficient, using about one gigajoule of energy per ton of carbon dioxide captured, consistently. Other existing methods have energy consumption which vary between 1 to 10 gigajoules per ton, depending on the inlet carbon dioxide concentration, Voskian says.
The researchers have set up a company called Verdox to commercialize the process, and hope to develop a pilot-scale plant within the next few years, he says. And the system is very easy to scale up, he says: “If you want more capacity, you just need to make more electrodes.”
###
Written by David L. Chandler, MIT News Office
Related links
Paper: “Faradaic Electro-Swing Reactive Adsorption for CO2 Capture.”
https://pubs.rsc.org/en/content/articlelanding/2019/ee/c9ee02412c#!divAbstract
New type of electrolyte could enhance supercapacitor performance
http://news.mit.edu/2019/new-electrolyte-supercapacitor-0812
Removing carbon dioxide from power plant exhaust
http://news.mit.edu/2019/removing-co2-from-power-plant-exhaust-0729
Turning emissions into fuel
http://news.mit.edu/2017/turning-emissions-into-fuel-1128
MIT researchers develop new way to clear pollutants from water
http://news.mit.edu/2017/electrochemical-clear-pollutants-water-0510
Getting the carbon out of emissions
http://news.mit.edu/2013/getting-the-carbon-out-of-emissions-0625
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
So – do we presume this technology will be deployed in the northern hemisphere? Where the OCO-2 satellite showed the enormous and widespread annual flux in CO2? And didn’t show up any really bad emitters that they were hoping to find? It showed that there was very little happening in the southern hemisphere.
OCO-3 was launched in July and is being installed in the ISS apparently. NASA seems to expect that this will finally produce some baddies, because the resolution will be much finer, but that doesn’t seem to have happened yet.
(I measure CO2 levels coming off the western Pacific at 19°S. Periodically, not continually. There is the usual diurnal fluctuation between about 380 and 425 ppm. I haven’t seen any significant change in annual average values over the past 7 years.
Sounds like a great way to purify air in closed systems like submarines, space craft and under ground habitations like bunkers. Or even reducing the CO2 in the supply air stream for combustion processes to boost efficiency.
The premise that CO2 is an evil gas is still being put forth. Perhaps this system on an individual use basis could have benefits for that user, but how large a system would be needed to actually have an effect on the climate?
Carbon dioxide isn’t the problem. Alarmists and other fools are.
Problem is the alarmists and fools are in charge.
Correctamundo!
Ok, fine but will the process really scale up to commercially viable size? Is a life cycle of 20,000 to 50.000 really possible (that’s quite a range by the way)?
I have actual experience in modifying processes involved with CO2 removal in natural gas processing. The original piping was carbon steel and just couldn’t stand up to the (CO2) rich amine stream. The acidic solution (H2CO3) caused extensive corrosion problems which we eventually solved with stainless steel. I’ve worked on other acid gas streams (H2S and CO2 are collectively called “acid gases”) but I won’t get into that now.
The combustion effluent from coal or natural gas power plants has a composition mainly composed of, surprise!, nitrogen. Well, yeah, as the atomsphere is roughly 79% nitrogen it will be the major constituent. As an example, the theoretical combustion of methane with air will result in one CO2, two H2O and 4.76 molecules of N2. In real life their is always a need for “excess air” to insure the fullest combustion of the methane possible. To much excess air results in additional N2 which need to be heated up too which is undesirable; you don’t want to heat up more non-reactant than necessary particularily in this casse when the size of the process is dependent on the amount of incoming effluent.
Why is this important? All of the equipment in any process involving the combustion effluent must account for the entire volume of gas and the conditions of the gas; it’s hot and at essentially atmospheric pressure hence the volume of the gas is very large. The process mentioned above operates at “room temperature and atomspheric pressure”. The pressure is fine but the effluent needs to be cooled to some temperature that the process will, hopefully, operate reliably on a continuous basis. There are processes that will cool the effluent but what may end up being a problem is the H2O in the stream. Some of the water and CO2 will end up making H2CO3 and the potential for corrosion and all the process materials will have to be designed with this in mind. In a coal fired plant the possibility of H2S from the sulfur in the coal (plus other compounds such as mercury) adds another level of complexity to the process.
Bottom line, the process should be scaled up to a pilot plant (WITHOUT public money financing) before anyone gets all excited about this miracle process which will “save the planet”.
On the other hand, the use of the process as a CO2 scrubber for enclosed habitats is very intriguing. This technology may have real benefits in those applications and should be persued.
Good points. I don’t think this technology wouldn’t necessarily preclude operation at higher temperatures. In fact, I think some potential advantages are around its ability to desorb CO2 without use of heating, as in typical amine scrubbers.
In natural gas reforming, issues of sulfur and other contaminants would not be a factor as they are removed to protect reforming catalysts up front. There are also specialized oxygen blown systems that get away from the N2 issue. Of course, air separation is expensive and in the end, the best economics should prevail.
I have the same overall opinion that you have, i.e., there are potential real benefits and it’s worthy of development.
In 20 years we will hear that trees, plants and other forms of life dependent on CO2 are dying.
Not useful for climate change; HUGELY useful for space environments.
For those of us old enough to remember, doesn’t this read a lot like the discovery of “Cold Fusion”? How’d that work out?
I only have a couple of questions. how is removing something from our atmosphere that our plant life needs in order to survive, going to save the planet?? and save it from what exactly??? existence??
MIT, I await your answers to those questions.
You can not plant a tree, because it is already a tree, that would be transplanting it. Plant tree seeds, to make more trees.
Tree nurseries plant tree seeds, growing into trees, small trees, but trees nonetheless. You get these trees from the nursery, planting these trees. Ask any Canadian summer tree planter, they plant thousands of trees, DAILY, and get eaten by black flies, millions and millions of black flies.
Except that at low concentrations the second law of thermodynamics more or less runs the show. All irreversibilities involved make concentration from very dilute mixtures fairly work intensive and thus expensive.
Sure! Let’s build and power enough of these “revolutionary” devices to process the entire atmosphere of the planet! Stephen Wright, the comedian, said it best: “It’s a small world, but I wouldn’t want to paint it…”
So is the last step building a gas pipe to space so we can blow it out of the atmosphere? How is separating CO2 helping remove it from the atmosphere where there is no place to put it in large enough quantities to make any measurable difference?
Oh, good lord — again with the grant/rent-seeking. It’s rampant.
October has been a great month! We got TWO “inventions that will change everything!”
Is this polyanthraquinone any good in a G&T?
‘the process ejects a stream of pure carbon dioxide.’
M’kay. How are you going to capture it? What are you going to do with it? [Venting it to atmosphere would be the best option.]
BWTM:
https://tallbloke.wordpress.com/2019/10/28/aluminium-air-power-cell-tech-set-to-make-a-comeback/
The future is so bright, we need sunglasses at night!
Sadly, the basic premise of all this pointless effort is false. Carbon dioxide is a precious, life-giving, beneficial trace gas without which terrestrial life would cease. The Sahara is greening. Forests are expanding. Earth is becoming greener, in the true sense. The prospect of the next glaciation is the real threat.
Suppose this thing were put into service all over the world.
In a few decades we’d all be singing:
“Where have all the flowers gone, long time passing?
Where have all the flowers gone, long time ago…”
The geniuses at MIT and elsewhere are very useful for thinking up stuff, but the implementation needs to be mitigated by us normals. As a non-genius in that environment, I know that many, if not most, times they have trouble noticing that the real world is not the same as the one in their labs.
If they could tweak the system around to where it could capture water vapor, then it would be useful as a quiet, non-warming dehumidifier.
How fascinatingly stupid!
Utter waste of time and resources.
“…In some soft-drink bottling plants, fossil fuel is burned to generate the carbon dioxide needed to give the drinks their fizz…”
Wait…so soft-drink bottling plants already have the technology to burn fossil fuels, capture the CO2, and inject it into soft-drinks?
Why don’t we just use that technology? Problem solved.
It’s not only soft-drinks, pasteurised beers (largers and things like that), need be re-fizzed after treatment.
So what these brilliant MIT science guys are saying is: We want another ice age to start and we want it now!!!
Just want to make sure I understand, since the only thing between us and a prolonged wet cold spell, which will have an unfortunate impact on crops and food production is the fact that we’re living in a warm period. Are these silly but very earnest fellow aware than in the Elizabethan period, when women wore NINE petticoats under the forepart and overskirt just to keep warm, chicken eggs (well, ANY eggs, really) were worth nearly their weight in gold? And wool was a hot commodity, and velvet was dress de jure because both wool and velvet were warmer than linen shifts and shirts? I made one of those court dresses, fully authentic, including the hoop, bumroll and doublet, and it does keep you much warmer on a chilly day than shorts and a t-shirt.
Really, I’d truly like to understand what has created this carbon phobia. I think these people, who expel carbon dioxide every time they exhale and speak, need some professional help with their problem. I really do.
I just wrote a similar comment and it is being reviewed?????
You are one hundred percent correct.
Brilliant science guys rarely know much about the real world we live in.
I know, I have one in the family.
In the UK last summer there was a shortage of CO2 for carbonated drinks because two reforming plants were down for maintenance (a planning error). I do not suppose the eco doomsters in the extinction movement even know that we deliberately produce CO2 by steam reforming hydrocarbons (n heptane) for the food and drinks industry – my MP certainly doesn’t he’s pushing for zero C emissions by 2050 or sooner now that he’s heard Greta preach. The crisis was averted by short term imports. This MIT invention if it’s not as big as the Empire State Building, (to provide the necessary interfacial area for such low concentrations as 400ppmv CO2) might be adapted as a stop gap but would need considerable additional equipment such gas boosters, compressors, HEs, liquefaction and storage plant etc. Solid CO2 was used extensively at one time for food preservation before domestic refrigerators became widely available – requiring lots of electrical energy of course. Little wonder that the Chinese are opening a new coal fired power station every five minutes; albeit along the silk road now.
I’m guessing the primary products are hydrogen and syngas and the CO2 formed is a byproduct. In any case, it’s pretty simple to make CO2.
Just mix some yeast in with some flour, eggs, salt and milk to make bread.
There are many many people who won’t accept CO2 (Bad yeast! Bad bad yeast) makes the bubbles in bread and beer etc.
removing carbon dioxide … a significant tool in the battle against climate change.
I see what they did there.
It is interesting that removing CO2 from the atmosphere would in the end bring about the very result global warming advocates warn us about. No wonder ideas like this are being pushed…because their predictions are not coming true. Talk about the proverbial finger on the scale.
Great science. A seemingly efficient method to capture CO2 that is used in many applications. As far as AGW is concerned ….. it answers a concern for some people. Whether the concern is real or not is irrelevant. Cost isn’t either if you look at current money being thrown at AGW. “Captured CO2” can become a recycling meme for the AGW needy and a revenue stream for others. It effectively negates the fossil fuel hysteria and all the angst that goes along with it. Expect little to no reporting in the media and active denial of its’ effectiveness from the AGW crowd. My guess is Nitrogen is being groomed to be the next bogeyman.
Nitrogen the next bogeyman? It already is as was shown here at WUWT with the protests in Holland about the EU imposed limits of N2 in the soils and in farming.
Why doesn’t the EU go the whole hog and ban civilisation, birth and farming?