Researchers believe they can boost the economic feasibility of carbon capture and storage by turning captured carbon into a useable product.
Scientists at the US Department of Energy’s Idaho National Laboratory (INL) have developed a process for turning captured carbon dioxide into syngas, a mixture made up primarily of hydrogen and carbon monoxide that can be used to make fuels and chemicals. The team has published its results in Green Chemistry, a publication of the Royal Society of Chemistry.
According to INL, traditional approaches for reusing the carbon from CO2 involve a reduction step that requires high temperatures and pressures. At lower temperatures, the CO2 doesn’t stay dissolved in water long enough to be useful.
The process developed at INL is said to address this challenge by using specialised liquid materials that make the CO2 more soluble and allow the carbon capture medium to be directly introduced into a cell for electrochemical conversion to syngas.
“For the first time it was demonstrated that syngas can be directly produced from captured CO2 – eliminating the requirement of downstream separations,” the researchers said in the paper.
The newly described process uses switchable polarity solvents (SPS), liquid materials that can shift polarity when exposed to a chemical agent. This property makes it possible to control what molecules will dissolve in the solvent.
In an electrochemical cell, water oxidation occurs on the anode side, releasing oxygen and hydrogen ions that migrate through a membrane to the cathode.
The hydrogen ions then react with bicarbonate (HCO3-, the form in which CO2 is captured in the SPS), allowing the release of CO2 for electrochemical reduction and formation of syngas.
On the release of CO2, the SPS switches polarity back to a water-insoluble form, allowing for the recovery and reutilisation of the carbon capture media.
In early experiments, too much hydrogen and not enough syngas was being produced. The results improved when the team introduced a supporting electrolyte to increase the ionic conductivity. Adding potassium sulphate increased electrolyte conductivity by 47 per cent, which allowed the efficient production of syngas.
INL add that when syngas can be produced from captured CO2 at significant current densities, it boosts the process chances for industrial application. Unlike other processes that require high temperatures and high pressures, the SPS-based process is said to have shown best results at 25 degrees C and 40psi.
The team has filed a provisional patent and is discussing the approach with a company involved in electrochemical technology research and development, Lister said.
“It integrates two areas that have been on parallel tracks: carbon capture and sequestration (CCS) and CO2 utilisation,” said Diaz Aldana, principal investigator on the experiment. “The problem with CCS has been its economic feasibility. If you can get some extra value out of the CO2 you are capturing, it’s a different story.”
Hang on – this is using power to turn carbon dioxide into fuel. That implies we’ve a greener power source available to drive the electrochemical cell. In that case, why did we burn fuel to create CO2 in the first place? Unless this is used for very specific applications, I suggest that for the most part we’d be better off using the green power source instead and cutting out the CO2 middle man entirely.
I wonder how many trees would need planting to make a significant dent in reducing global CO2 by capturing it the natural way, presumably the Oxygen byproduct would be quite useful…. 🙂
This looks like thermodynamic madness: reduce the efficiency of power generating to produce a fuel stream. Otherwise, this could be a perpetual motion machine in disguise.
I must agree with TF that trees are by far the best means of CCS, but we are destroying these rapidly in the name of “Green power”, plus of course, urban spread.
Sounds like an expensive (energy & money) solution to a non problem.
I’m still waiting for someone to supply some empirical evidence of man-made carbon dioxide induced global warming, & explain the actual mechanism that produces that unique effect & in particular the laws of physics that allows 1 molecule in 2,500 to increase the the temperature of something hotter than it’s self.
Nobody seems able to….why is that I wonder ?
I would refer this reader to John Tyndall’s experiments on the heat-trapping effects of atmospheric gasses and vapours, conducted in 1859, and to Svante Arrhenius’s calculations of how increases in carbon dioxide levels would change surface temperatures; these were published in 1896.
Sorry to dive in to this, but the Tyndal experiment, like Al Gore’s famous one have not been replicable and are there is no reasonable doubt that Gore’s experiment was fraudulent. The Arrhenius “Greenhouse gas” calculations are also based on incorrect gas radiation modelling yet underline the IPCC Radiative Forcing Function that underpin all global warming theory. A short assessment of the RFF section of the IPCC gigantic reports should be enough to convince any scientist or engineer that the basis is very dubious: the decisive RFF being the resultant of a committee’s deliberations rather than scientific method.
Stuart ,
Sorry this has to be a bit long.
John Tyndall’s experiments on gasses & vapours shows nothing more than that EMR from a warmer object is absorbed by a colder one. Such absorption is not proof of a greenhouse effect. There is no energy production and no greenhouse-style warming.
The Arrhenius GHG theory stems from the 19th century pseudoscientific notion that heat was actually a fluid (called “caloric”). His GHG theory was refuted by fellow Swede Knut Ångström (1900), Robert Wood (1909) & many times since.
Arrhenius'(1896) first error was to assume that greenhouses and hotboxes work as a radiation trap.; but Fourier (1824) had already explained quite clearly that such structures simply prevent the replenishment of the air inside (via convection), allowing it to reach much higher temperatures than are possible in circulating air.
See Fourier, 1824, translated by Burgess, 1837
(* Earths atmosphere is open & convective; it’s not a constrained enclosure. *)
Contrary to what Arrhenius (1896, 1906) and many popular authors may claim (Weart, 2003; Flannery, 2005; Archer, 2009), Fourier did not consider the atmosphere to be anything like glass. In fact, Fourier (1827, p. 587) rejected that comparison by stipulating the impossible condition that, in order for the atmosphere to even remotely resemble the workings of a hotbox or greenhouse, layers of the air would have to solidify without affecting the air’s optical properties.
Yet, his fundamental misunderstanding of the physics of greenhouses has been perpetuated.
Even whilst Arrhenius was formulating his theory, Maxwell, 1864; Boltzmann 1877: Heaviside, 1881; Hertz, 1888: Thompson 1896, had discovered the radiative gas laws, mathematically formalised by Planck (1901), confirmed by Einstein (1905) that prove Arrhenius was in error.
I recommend downloading ‘The thermal behaviour of gases under the influence of infrared-radiation’ by T Allmendinger – 2016.
I still eagerly await the laws of physics that will allow 1 molecule in 2,500 to increase the the temperature of something hotter than it’s self.….. for then we will have discovered a source of perpetual energy.
Whilst I share skepticism of the extent of warming from CO2 which ranges from a universally accepted (and benign) 1 degree per doubling to many times that value from highly speculative ‘positive feedbacks’ pre-built into the models (but without any empirical proof that they exist), it is a fact that there is an established greenhouse effect from cool clouds. It helps to think of it as delayed cooling rather than heating. That is, the outgoing radiation is absorbed and re-emitted by greenhouse gases and this slows the cooling during night-time prior to re-heating during daytime as the Earth turns round again. This delayed cooling is the putative greenhouse effect, which is just badly named because real greenhouses mostly heat up due to lack of convection. It is the bad terminology that confuses the issue: Engineers brought up on the 2nd law are not used to heating by apparently cool objects. However the initial heating in this case is of course by the sun, a much hotter object. That initial heat is simply prevented from escaping the atmosphere. The physics is all there, the only question is the extent and direction of the feedbacks and the empirical proof thereof.
“The extend and direction of feedbacks and the empirical proof thereof” this is the question, says James Gardiner.
I must say it is hard for me, as layman, to understand why no-one studying for a PhD has taken this essential gap in our knowledge on-board and settled it once and for all. Such an important issue this is.
I live right by the sea, which lies just behind our pampas grass and worry constantly about the constant negative discussions about what it may be like to live here in 50 years time.
So please, all the budding physics and engineering students reading this, please get on and sort this out once and for all!
James, you say “the outgoing radiation is absorbed and re-emitted by greenhouse gases and this slows the cooling during night-time”; Absolutely correct.
That’s natures perfect example of which of the radiative “GH” gases is in control;
On a cloudy night it’s all warm & cuddly, but on a clear night…. it’s brass monkeys.
• The “GH effect” in the atmosphere is a fact & is caused by the radiative “GH” gases:
H2O = 81 %;
CO2 = 13 %;
O3 = 4 %;
CH4 & N2O = 1 %;
CO2 molecules can absorb radiation and then transfer that energy by re-radiation. Gasses do not conduct heat well, (except water vapor). There is a reason why most good insulating materials are mostly dry air.
A good understanding of this issue can be obtained from Staley,D.O., and Jurica,G.M., “Effective atmospheric emissivity under clear skies” J.Applied Meteorology,v.11,349-356,March 1972. The physics of radiation transport in gas mixtures was well established many years ago.
Radiation doesn’t heat until it hits a receptive target; it passes straight thru the atmosphere unless it’s at a very specific frequency to a gas molecule THAT REACTS AT THAT FREQUENCY. (It works exactly the same for your radio which is tuned to one station on the many that are transmitted thru the air).
Convection heats…and cools.
• CO2 is logarithmic (that fact, accepted by alarmists & repeatedly documented by IPCC reports) and so the more CO2 we have in the atmosphere, the less any additional CO2 matters.
CO2 is a complex molecule but it isn’t magic. It is about 0.04% of the atmosphere.
The atmosphere is about 0.1% of the heat capacity of the ocean/atmosphere system.
The oceans hold about 99.9% of the heat energy in the system. The mass of the oceans is about 24x the mass of the atmosphere. The heat holding capacity of water is 4.2x dry air. The clue that the oceans are the most important part is the seasonal fluctuation in the number and power of storms.
The oceans cool themselves & warm the atmosphere (latent heat of evaporation); the atmosphere cools by latent heat of condensation & radiation.
In determining the climate, the oceans are the dog & the atmosphere is the tail. CO2 is the flea.
Well the water vapour and cloud data (the main +ve and -ve feedbacks) are scatter-graphs with huge variance that engineers would not attempt to put a line through and declare any increase or decrease (though innumerate researchers do so routinely). However the sea level has been rising since the last ice age. If it fell then it would indicate the onset of a new ice age. I doubt anyone will wait until the water reaches their neck before they build a defence and neither is anyone stopping their headlong rush to live by the sea because the reality is that we are pretty exceptional at reclaiming land from the sea anyway. First in line for any tsunami though!
The most likely plan at least near to medium term, would be to use the currently “curtailed renewables” or “overflow renewables” when the grid has to shut down wind or solar producers. In California 80 GWH worth of wind and solar were curtailed in March 2017. And as more solar plants and panels get manufactured, this is only going to get “worse”. However with this technology this problem could turn into an opportunity and fast.