patent on magnetic separation of oxygen from air

making oxygen-how to use magnets to separate oxygen from air | science and technology - eminetra

making oxygen-how to use magnets to separate oxygen from air | science and technology - eminetra

OXYGEN is important.. Literally for breathing, and therefore for many inpatients. And figuratively, it applies to the industries that use it in their processes, from steelmaking to pharmaceuticals. Therefore, the global gas market is large. According to various estimates, it was between about $ 28 billion and $ 49 billion in 2019.

However, it can be larger. A series of reactions, including oxygen and steam, can convert fossil fuels such as coal and natural gas into the energy sources hydrogen and carbon dioxide, which can be separated and sequestered underground. It may enable their continued employment in a world of limited greenhouse gas emissions. However, it requires a cheap and abundant supply of oxygen. Thats why the US Department of Energy is sponsoring a project that aims to use magnets to extract oxygen from the atmosphere.

Dry air is a mixture of 21% oxygen, 78% nitrogen, 1% argon and other trace gases such as carbon dioxide. Today, most of the pure oxygen in the world is made by liquefaction followed by distillation of air, separating the air into its constituents. This is done in a large factory. Another source of oxygen, which is slightly less pure, is a small, mobile plant called an oxygen concentrator. They absorb nitrogen into a porous material called zeolite, leaving a gas that is 90% oxygen, or force air through a membrane that is more permeable to one gas than the other, making it slightly thicker. Produces no mixture. The magnetic separation alternative is the brainchild of John Vetrovec, the boss of Aqwest, a technology company in Larkspur, Colorado.

Oxygen cannot be permanently magnetized like elements like iron, but it is attracted to magnetic fields. As a result, when air is pumped through such fields, the oxygen concentrates in those places where the fields are strongest. This improvement in concentration is small. However, if the oxygen-rich part of the airflow can be separated from the oxygen-deficient part and treated over and over again in the same way, it will be concentrated until it is pure enough to be useful. can do. Dr. Betrobeck believes he knows how to do this.

Previous attempts by another group of engineers used pulsed electromagnets. However, this required both the high voltage, which is expensive to build, and the electromagnet itself, which is expensive to buy and run. Dr. Betrobeck will perform his version of the trick at atmospheric pressure, using permanent magnets. Both of these changes significantly reduce power consumption. In fact, the only moving part of the device is the blower that pushes the air.

A magical addition to Aqwests party is a series of structures called microchannels. These are tubes less than 1 mm in diameter intended to carry liquids or gases. The important thing is that those narrow bores ensure a laminar flow of fluid through them. Translated from the story of physics, this means that it does not cause turbulence, so there is no mixture of their content. It allows them to act as a gas separator for company equipment.

At first glance, the first result is not very impressive. The prototype results in a concentration increase of about 0.1% per passage, but Dr. Vetrovec believes his team can raise this to 0.4%. But the important thing is repetition. As a reward for a service, like the story of the Chancellor who asked the king about the oxygen concentration, such as one grain of rice in the first square of the chess board, two grains in the second, and four grains in the third. It rises rapidly with continuous repetition. Thirty passages at a higher rate yield a 90% concentration of oxygen, which is commercially useful.

It remains to be seen if this approach proves to be cheaper than the actual established alternatives, and if so, whether it really saves fossil fuel bacon. However, some future versions of green energy involve the use of large amounts of hydrogen, so better ways to produce that gas are always welcomed. Meanwhile, many other users of oxygen will certainly welcome cheap sources. The idea of doing this with a magnet is fascinating.

magnetic separation of air | reb research blog

magnetic separation of air | reb research blog

Assome of you willknow, oxygen is paramagnetic, attracted slightly by a magnet. Oxygens paramagnetism is due to thetwo unpaired electrons in every O2 molecule.Oxygenhas a triple-bond structure as discussed here(much of the chemistry you were taught is wrong). Virtually every other common gas is diamagnetic, repelled by amagnet. These includenitrogen, water, CO2, and argon all diamagnetic. As a result, you can do a reasonable job of extracting oxygen from air by the use of a magnet. This is awfully cool, and could make for a good science fair project, if anyone is of a mind.

But first some math, or physics, if you like. To a good approximation the magnetization of a material, M = CH/T where M is magnetization, H is magnetic field strength, C is the Curie constant for the material, and T is absolute temperature.

Ignoring for now, the difference between entropy and internal energy, but thinking only in terms of work derived by lowering a magnet towards a volume of gas, we can say that the work extracted, and thus thedecrease in energy of themagnetic gas is HdM = MH/2. At constant temperature and pressure,we can say G = -CH2/2T.

The maximum magnetization youre likely to get with any permanentmagnet(not achieved to date) isabout 50 Tesla, or 40,000 ampere meters. At 20C, the per-mol, magnetic susceptibility of oxygen is1.34106 This suggests that the Curie constant is 1.34 106x 293 = 3.93 104. Applying this value to oxygen in a 50 Tesla magnet at 20C, we find the energy difference, G is 1072J/mole = RT ln where is aconcentration ratio factor between the O2 content of the magnetized and un-magnetized gas, C1/C2 =

At room temperature, 298K = 1.6, and thus we find that the maximum oxygen concentration youre likely to get is about 1.6 x 21% = 33%. Its slightly more than this due to nitrogens diamagnetism, but this effect is too small the matter. What does matter is that 33% O2 is a good amount for a variety of medical uses.

I show below my simple design for amagneticO2 concentrator. The dotted line is a permeable membrane of no selectivity with a little O2 permeability the design will work better.All you need is a blower or pump. A coffee filter could serve as a membrane.

Thisdesign is as simple as the standard membrane-based O2 concentrator those based on semi-permeable membranes, but this design should requirelesspressure differential just enough to overcome the magnet. Less pressure means the blowershould besmaller, andless noisy, with less energy use. I figure this could be really convenient for people who need portable oxygen. With current magnets it would take4-5stages or low temperatures to reach this concentration, stillthis design could have commercial use, Id think.

On the theoretical end, aninteresting thing I find concerns the effect on the entropy of the magnetic oxygen. (Please ignore this paragraph if you have not learned statistical thermodynamics.) While you might imagine that magnetization decreases entropy, other-things being equal because the molecules are somewhat aligned with the field,temperature and pressure being fixed, Ive come to realize that entropy is likelyhigher. Asea of semi-aligned molecules will have a slightly higher heat capacity thannonaligned molecules because the vibrational Cp is higher, other things being equal. Thus, unless Im wrong, the temperature of the gas will be slightly lowerinthe magnetic areathanin the non-magnetic field area. Temperature and pressure are not the same within the separator as out, by the way; the blower is something of acompressor, though a much less-energy intense one than used for most air separators. Because of the blower, both the magnetic and the non magnetic air will be slightly warmer than in the surround(blower Work = T/Cp). This heat will be mostly lost when the gas leaves the system, that is when it flows to lower pressure, both gas streams will be, essentially at room temperature. Again, this is not the case with the classic membrane-based oxygen concentrators there the nitrogen-rich stream is notably warm.

I love learning about neodymium magnets. These things are so interesting and powerful I am glad the processing and separation industry is using them to their benefit. Ive never seen them used for air separation though.

Robert, I note that you mention 50 Tesla for a Neo Magnet. That would imply 50,000 Gauss,, which exceeds typical 8000 Gauss from a non yoked magnet, and more than the roughly 18000 gauss saturation point of a high flux yoke (polepiece) flux concentrator. Is this a typo, and does it influence the final result? Great article btw. Best Regards Mike Lindberg

magnetism - could a magnet pull oxygen out of the air? - chemistry stack exchange

magnetism - could a magnet pull oxygen out of the air? - chemistry stack exchange

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I read that the $\ce{O2}$ molecule is paramagnetic, so I'm wondering: could a strong magnet pull the $\ce{O2}$ to one part of a room enough to cause breathing problems for the organisms in the room?

I'm a physicist, so apologies if the answer below is in a foreign language; but this was too interesting of a problem to pass up. I'm going to focus on a particular question: If we have oxygen and nothing else in a box, how strong does the magnetic field need to be to concentrate the gas in a region? The TL;DR is that thermal effects are going to make this idea basically impossible.

The force on a magnetic dipole $\vec{m}$ is $\vec{F} = \vec{\nabla}(\vec{m} \cdot \vec{B})$, where $\vec{B}$ is the magnetic field. Let us assume that the dipole moment of the oxygen molecule is proportional to the magnetic field at that point: $\vec{m} = \alpha \vec{B}$, where $\alpha$ is what we might call the "molecular magnetic susceptibility." Then we have $\vec{F} = \vec{\nabla}(\alpha \vec{B} \cdot \vec{B})$. But potential energy is given by $\vec{F} = - \vec{\nabla} U$; which implies that an oxygen molecule moving in a magnetic field acts as though it has a potential energy $U(\vec{r}) = - \alpha B^2$.

Now, if we're talking about a sample of gas at a temperature $T$, then the density of the oxygen molecules in equilibrium will be proportional to the Boltzmann factor: $$ \rho(\vec{r}) \propto \mathrm e^{-U(\vec{r})/kT} = \mathrm e^{-\alpha B^2/kT} $$ In the limit where $kT \gg \alpha B^2$, this exponent will be close to zero, and the density will not vary significantly from point to point in the sample. To get a significant difference in the density of oxygen from point to point, we have to have $\alpha B^2 \gtrsim kT$; in other words, the magnetic potential energy must comparable to (or greater than) the thermal energy of the molecules, or otherwise random thermal motions will cause the oxygen to diffuse out of the region of higher magnetic field.

So how high does this have to be? The $\alpha$ we have defined above is approximately related to the molar magnetic susceptibility by $\chi_\text{mol} \approx \mu_0 N_\mathrm A \alpha$; and so we have1 $$ \chi_\text{mol} B^2 \gtrsim \mu_0 RT $$ and so we must have $$ B \gtrsim \sqrt{\frac{\mu_0 R T}{\chi_\text{mol}}}. $$ If you believe Wikipedia, the molar susceptibility of oxygen gas is $4.3 \times 10^{-8}\ \text{m}^3/\text{mol}$; and plugging in the numbers, we get a requirement for a magnetic field of $$ B \gtrsim \pu{258 T}. $$ This is over five times stronger than the strongest continuous magnetic fields ever produced, and 25100 times stronger than most MRI machines. Even at $\pu{91 Kelvin}$ (just above the boiling point of oxygen), you would need a magnetic field of almost $\pu{150T}$; still well out of range.

1 I'm making an assumption here that the gas is sufficiently diffuse that we can ignore the magnetic interactions between the molecules. A better approximation could be found by using a magnetic analog of the Clausius-Mossotti relation; and if the gas gets sufficiently dense, then all bets are off.

A process for separating O$_2$ from air, that includes the steps effecting an increase in pressure of an air stream, magnetically concentrating O$_2$ in one portion of the pressurized air stream, the one portion then being an oxygen rich stream, and there being another portion of the air stream being an oxygen lean stream, compressing the oxygen rich stream and removing water and carbon dioxide therefrom, to provide a resultant stream, and cryogenically separating said resultant stream into a concentrated oxygen stream and a waste stream.

I would say the yes is conditional in that you'd probably need a room that is sealed from communication with the atmosphere (otherwise equilibrium will be re-established with respect to oxygen pretty quickly), is vented to the outside in order to dispose of the oxygen, houses one heck of a strong magnet, and has a strongly-locked door to prevent the unfortunate organisms from leaving.

No, to separate oxygen from air you need extremely high gradients of field strength. in this paper http://link.springer.com/article/10.1007%2Fs11630-007-0079-1#page-1 they used about $\pu{0.4T}$ per $\pu{mm}$, but to cause breathing problems it is enough to get the $\ce{O2}$ concentration below 17%, so lets say $\pu{0.1T/mm}$ is needed. To sustain such gradients over a whole room (lets say 4 meters), the field strength on one side of the room needs to be around $\pu{400T}$, which is very likely to kill humans (dissolved ions begin to circle due to lorentz force instead of going where they should, moving around induces huge currents), and has never been achieved in a continuous field. (from nationalmaglab.com: 45-Tesla hybrid magnet, which offers scientists the strongest continuous magnetic field in the world)

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making oxygen - how to separate oxygen from air using magnets | science & technology - glassmerchantsbalaclava

making oxygen - how to separate oxygen from air using magnets | science & technology - glassmerchantsbalaclava

OXYGEN IS VITAL. Literally so for breathing, and thus for many hospital patients. And metaphorically for industries ranging from steelmaking to pharmaceuticals, which use it in their processes. The world market for the gas is therefore large. Various estimates put it as having been between about $28bn and $49bn in 2019.

It could, though, be larger. In a set of reactions that also involve oxygen and steam, fossil fuels such as coal and natural gas can be turned into hydrogen, a source of energy, and carbon dioxide, which can be separated and sequestered underground. That might allow their continued employment in a world of restricted greenhouse-gas emissions. It would, however, require a cheap and abundant supply of oxygen. Which is why Americas Department of Energy is sponsoring a project intended to pull oxygen from the atmosphere with magnets.

Dry air is a mixture of 21{c25493dcd731343503a084f08c3848bd69f9f2f05db01633325a3fd40d9cc7a1} oxygen, 78{c25493dcd731343503a084f08c3848bd69f9f2f05db01633325a3fd40d9cc7a1} nitrogen and 1{c25493dcd731343503a084f08c3848bd69f9f2f05db01633325a3fd40d9cc7a1} argon, with a few other trace gases such as carbon dioxide. At the moment, most of the worlds pure oxygen is made by the liquefaction and subsequent distillation of air, to separate it into its components. This is done in large factories. The other source of oxygen, somewhat less pure, is small, mobile plants called oxygen concentrators. These either absorb the nitrogen into a porous substance called a zeolite, leaving behind a gas that is 90{c25493dcd731343503a084f08c3848bd69f9f2f05db01633325a3fd40d9cc7a1} oxygen, or force air through membranes more permeable to one gas than the other, yielding a somewhat less rich mixture. The alternative of magnetic separation is the brainchild of John Vetrovec, boss of Aqwest, a technology firm in Larkspur, Colorado.

Though oxygen cannot be magnetised permanently in the way that elements like iron can, it is attracted by magnetic fields. As a consequence, when air is pumped through such a field its oxygen gets concentrated in those places where the field is strongest. This concentration-enhancement is small. But if the oxygen-enriched part of the air stream could be separated from the oxygen-impoverished part, and then treated in the same way over and over again, it could be enriched to the point where it was pure enough to be useful. Dr Vetrovec thinks he knows how to do this.

A previous attempt by a different group of engineers used pulsed electromagnets. This, though, required both high pressure, which is expensive to create, and the electromagnets themselves, which are costly to buy and costly to run. Dr Vetrovec intends to perform his version of the trick at atmospheric pressure, and using permanent magnets. Both of these modifications greatly reduce power consumption. In fact, the devices only moving part is the blower which pushes air through it.

The magic extra ingredient Aqwest brings to the party is an array of structures called microchannels. These are tubes less than a millimetre in diameter that are intended to carry liquids or gases. Crucially, their narrow bores ensure the laminar flow of any fluid passing through them. Translated from physics-speak, this means they cause no turbulence, and therefore no mixing of their contents. That allows them to act as gas separators in the firms device.

On the face of things, the initial results do not look that impressive. Prototypes yield a concentration increase of around 0.1{c25493dcd731343503a084f08c3848bd69f9f2f05db01633325a3fd40d9cc7a1} per passage, though Dr Vetrovec thinks his team can raise this to 0.4{c25493dcd731343503a084f08c3848bd69f9f2f05db01633325a3fd40d9cc7a1}. The key, though, is the repetition. Like the tale about a vizier who asked his king, as a reward for some service, for a grain of rice on the first square of a chess board, two grains on the second, four on the third, and so on, the oxygen concentration rises rapidly with successive iterations. Thirty passages at the higher rate would yield a 90{c25493dcd731343503a084f08c3848bd69f9f2f05db01633325a3fd40d9cc7a1} concentration of oxygenand that would be commercially useful.

Whether this approach actually will prove cheaper than the established alternatives, and whether, if it does, that will really save fossil fuels bacon, remain to be seen. But some versions of a green-energy future involve the use of a lot of hydrogen, so better ways of generating that gas are always welcome. In the meantime, oxygens many other users would surely welcome a cheaper source of supply. The idea of doing this with magnets is attractive.

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a novel magnetic separation oxygen-enriched method and the influence of temperature and magnetic field on enrichment | springerlink

a novel magnetic separation oxygen-enriched method and the influence of temperature and magnetic field on enrichment | springerlink

A novel oxygen-enriched method is presented. Using two opposite magnetic poles of two magnets with certain distance forms a magnetic space having a field intensity gradient near its borders. When air injected into the magnetic space outflows from the magnetic space via its borders, oxygen molecules in air will experience the interception effect of the gradient magnetic field, but nitrogen molecules will outflow without hindrance. Thereby the continuous oxygen enrichment is realized. The results show that the maximum increment of oxygen concentration reaches 0.49% at 298 K when the maximum product of magnetic flux density and field intensity gradient is 563T2/m. The enrichment level is significantly influenced by the gas temperature and the magnetic field. The maximum increment of oxygen concentration drops to 0.16% when the gas temperature rises to 343 K, and drops to 0.09% when the maximum product of magnetic flux density and gradient is reduced to 101 T2/m from 563 T2/m.

Yang, L J, Ren, J X, Song, Y Z, et al. Convection heat transfer enhancement of air in a rectangular duct by application of a magnetic quadrupole field. International J. of Engineering Science, vol.42, pp.491507, (2004).

Ohara, T, Ichida, T, Ooura, H, et al. Experiment on Oxygen Enrichment of Air Using Superconducting High Intensity Magnetic Field. Iho/Bulletin of the Electrotechnical Laboratory, vol.48, pp.928935, (1984).

Wang, L., Cai, J., Wu, P. et al. A novel magnetic separation oxygen-enriched method and the influence of temperature and magnetic field on enrichment. J. of Therm. Sci. 16, 7983 (2007). https://doi.org/10.1007/s11630-007-0079-1

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