Half a croissant, on a plate, with a sign in front of it saying '50c'
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Nested Gas Storage Vessel

Store more gas in a smaller space
  (+12, -1)(+12, -1)
(+12, -1)
  [vote for,

Current materials technology limits the pressures at which gas can be stored. However, the absolute pressure is not important, more the difference between the pressure on the inside of the vessel and the outside. So, if we take a very large vessel say at 100bar, inside this we can put a smaller (1/2 volume) cylinder OF IDENTICAL CONSTRUCTION at 200bar. So a 100m3 vessel that would normally be able to hold 100m3 at 100 bar could have a 50m3 vessel nested inside it. The original vessel loses 50m3 to the smaller vessel, however the smaller vessel can run at double pressure storing 100m3. The total would be 150m3. A 50% increase. Inside the smaller vessel a still smaller vessel could run at double the pressure again and so on. Ideally this would all be controlled by pumps situated on each nested cylinder, these would take gas from the larger vessel and compress it into the smaller ones. Valves would control release. This would simplify the whole process having only one main fill/release port.
bs0u0155, Jul 27 2010


       Just how high a pressure are you trying to store gasses at? Standard scuba tanks, I believe, run upwards of 200 bar, and heavy industrial tanks can go significantly higher.   

       Your major limiting factor is not the tank design, but your pump/fitting strength. Your nested pumps would deal with this, but given the difficulty of servicing the nested pumps would offset the much of the advantage.
MechE, Jul 27 2010


       I was just thinking that the other day: if your next two posts concern hydraulic free piston engine efficiency I'm going to half-sue.   

       The app I had in mind was for a hydraulic system with the reservoir tank built around the accumulator tank. Upside of course is greater safety and smaller footprint. Downside is a greater surface area for the "sides" of the reservoir tank and hose, means pumping losses and, as MechE points out, more fiddlyness.   

       // difficulty of servicing the nested pumps// just turn the nested stopcock to the OFF position and proceed.
FlyingToaster, Jul 27 2010

       I'm pretty much in the dark when it comes to the technicalities of pumping gas about to be fair. My thinking was that you could peel away a layer so to speak. So simply allow the gas in the outer most chamber to fall to atmospheric (with the corresponding percentage drop in all interior nested tanks) then you can simply walk in and service it while all of the inner layers are still in service. Of course eventually you'll have to close the whole thing down, or perhaps leave a robot in there, or perhaps put more pumps in for redundancy.
bs0u0155, Jul 27 2010

       Nice idea.   

       What are you trying to save, though? I ask because you could just make the outer tank of thicker, stronger material. This of course would add cost and weight, but so does having nested vessels.   

       One other thing: pressure vessels get stronger as they get smaller: a small vessel can take more internal pressure than a large vessel made of the same type and thickness of material. So you need to compare the advantage of nested vessels not just with a single vessel with thicker walls, but also with a bundle of smaller vessels.
MaxwellBuchanan, Jul 27 2010

AbsintheWithoutLeave, Jul 27 2010

       I was primarily thinking of space saving. Or possiby a way of increasing the energy density of compressed air for use in compressed air hybrid vehicles. Also if you Google "gas storage" the overwhelming impression is that of size. That, and I like the idea of a large gas storage facility being painted like a Russian doll in honor of the technology inside.
bs0u0155, Jul 27 2010

       // bundle of smaller vessels //   

       The MCP or "Multi Cylinder Pallet" uased for Hydrogen and Acetylene, amongst others.   

       This would probably work on the scale of a VLCC - sized gas transporter, but complexity/weight factors would tell against it on a smaller scale. And it's only useful for gas, not for liquid in equilibrium with its vapour.   


       Taking this to its logical conclusion, the innermost vessel should be as large as possible. So instead of being "nested" like Russian dolls, it's a multiwalled tank with each layer supporting the one inside. The amount of "dead" volume between each tank skin actually needs to be minimised for maximal efficiency; just enough room for the compressors and valve gear.
8th of 7, Jul 27 2010

       I'd thought of this, but thought the 50% thing would come across better in the description. However I kind of un-thought it, as with very small volume layers, there's not a lot of buffering in the system on fill up. But that's a minor criticism.
bs0u0155, Jul 27 2010

       How much buffering does it need ?   

       You just need to control the pressure between the layers so they don't implode or explode.   

       In a reductio-ad-absurdum design, you could make the tank from layers of PVC membranes, each one capable of withstanding only fractions of a Bar, and yet the inner vessel would still be capable of crushing normal gas into degenerate matter ...
8th of 7, Jul 27 2010

       Is it relative pressure difference or absolute pressure difference which is important?
I'd have thought the latter : a vessel rated to 100 bar could stand 200 bar in a 100bar atmosphere, 300 bar in a 200 bar atmosphere and so on.

       If that's the case, you can't double the pressure each time.   

       Otherwise you could presumably make even very high-rated vessels explode by tiny absolute pressure differences at near vaccuum.   

       So given that - is there any reason not to just make the external wall multiple times thicker?
Loris, Jul 27 2010

       //Taking this to its logical conclusion, the innermost vessel should be as large as possible. So instead of being "nested" like Russian dolls, it's a multiwalled tank with each layer supporting the one inside. The amount of "dead" volume between each tank skin actually needs to be minimised //   

       And taking it to an even more logical conclusion, the "dead" volume would be an interatomic gap, giving you a single vessel with a thick wall.
MaxwellBuchanan, Jul 27 2010

       Hahaha, beat you too it Maxey old boy.
Loris, Jul 27 2010

MaxwellBuchanan, Jul 27 2010

       hmm, but a vacuum is only around 1 bar below atmospheric, so a 100bar vessel would be able to take 99bar in a vacuum surely?
bs0u0155, Jul 28 2010

       That's quite amazingly profound, and yet somehow strangely not ...   

       Sp. Shirley
8th of 7, Jul 28 2010

       I nearly put "vacuum atmosphere"... nearly.
bs0u0155, Jul 28 2010

       This is essentially a bomb that goes off if the pressure of the outer vessel is somehow lost.
ldischler, Jul 28 2010

       I'd thought of that, kind of a pressure domino effect, but the same applies to normal pressure vessels, just to a slightly lesser effect.
bs0u0155, Jul 28 2010

       //hmm, but a vacuum is only around 1 bar below atmospheric, so a 100bar vessel would be able to take 99bar in a vacuum surely?//   

In the idea you've assumed you can double the pressure in each vessel. That's fine for the first internal vessel, at 2x pressure in a 1x pressure environment. But for the next one, you propose 4x pressure, when it could only really take 3x pressure in the 2x -pressure environment.

       Given that, you don't get any gain over just having a single container with a stronger wall.   

       And stop calling me surely.
Loris, Jul 29 2010

       [ldischler] -//essentially a bomb// - true, but the cool thing is that it goes off in steps as the shells blow.   

       Imagine how much Hollywood will love pyro FX of a bomb that just keeps going off!
lurch, Jul 29 2010

       That would be the perfect weapon for an assassin clown: nested helium balloons with a 1000 PSI core.
AntiQuark, Aug 01 2010

       // assassin clown //   

       Horrible, terrifying, and yet strangely compelling ...
8th of 7, Aug 01 2010

       As the helium balloon can expand the pressure would tend to equalize.
Voice, Aug 02 2010

       LORIS, you're right, dammit. The principle holds kind of true for the first one but none after that, bugger.
bs0u0155, Aug 18 2010

       Really, stop voting this idea up, it's not so great, I'm leaving it up as a thought experiment, one I went through in reality and came out wiser...
bs0u0155, Dec 02 2011

       //Really, stop voting this idea up// Or what?! Hah
DIYMatt, Dec 04 2011

       It's not a bad idea, just an irrelevant one. Making gas bottles more compact is a lofty goal, but in the vast majority of current applications for pressurized gas (industrial and medical use), capacity vs. weight is more important than capacity vs. volume.
Alterother, Dec 04 2011

       You may be reasoning backwards. The current range of applications for pressurized gas is probably influenced by the current state of the art in pressurized gas storage. Invent a system that optimizes capacity per volume, and new applications will* arise.   

       *So I assert. Seems to work that way, a lot, in technology.
mouseposture, Dec 04 2011

       Possibly, but most situations that call for space-saving measures also call for weight-saving as well. This idea could feasibly pack 50-60 lbs of oxygen into something the size of a 30 lb bottle, but would have a greater dry weight than said, meaning my portable oxyfuel setup would be a whole lot less portable, even when nearly empty.
Alterother, Dec 04 2011

       + has to be better than burning it off. Which they do.
Zimmy, Dec 05 2011

       The pump also works on pressure DIFFERENCE. So pumping up from outer to inner should be possible with the same equipment.   

       A better approach would be to mimic biology and have a counter-current multiplier system.   

       You would constantly be pumping with minute low energy pumps along pipes in pipes with the middle section having extremely high pressure, actively created from all directions.   

       Valves of these minute pumps should be remotely controlled, for controlled hold of gas (closed valves) and release (open).
pashute, Aug 17 2012

       //Valves of these minute pumps should be remotely controlled//
Perhaps offering gainful employment for some of Maxwell's demons.
AbsintheWithoutLeave, Aug 28 2012

       I think this idea needs to be turned into its Bizarro twin. It is the perfect scheme for that philsopher's stone of LTA, the Vacuum Balloon. Each layer has less pressure until the center is 99.44% pure vacuum without the need for megastruts or the like.
bungston, Aug 09 2017

       // It is the perfect scheme for that philsopher's stone//   

       No. The perfect scheme for that philosopher's stone is gallbladder surgery.
MaxwellBuchanan, Aug 09 2017

       Perhaps, but "Harry Potter and the impromptu gall-bladder operation to remove calculi" probably wouldn't have made Ms. Rowling the millionairess she is today...
8th of 7, Aug 09 2017


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