초록 ▼

A method for storing hydrogen is described. The hydrogen is infused into hollow spheres. The spheres are made from a polymer which has a tensile strength sufficient to contain hydrogen under selected internal pressure conditions; and has a permeation coefficient which can be adjusted under variable

A method for storing hydrogen is described. The hydrogen is infused into hollow spheres. The spheres are made from a polymer which has a tensile strength sufficient to contain hydrogen under selected internal pressure conditions; and has a permeation coefficient which can be adjusted under variable humidity conditions. Adjustment of the humidity level after the hydrogen is infused results in the walls of the spheres becoming impermeable to hydrogen. The hydrogen stored in the spheres can then be released at a desired time by readjusting the humidity level. The released hydrogen can be directed to any type of equipment which is fueled by hydrogen or otherwise uses the gas. Related articles and systems are also described.

대표청구항 ▼

What is claimed is: 1. A method for storing hydrogen, comprising the following steps: (a) infusing hydrogen into hollow spheres which have gas-permeable walls, wherein the spheres comprise a polymer which (i) has a tensile strength sufficient to contain hydrogen under selected internal pressure con

What is claimed is: 1. A method for storing hydrogen, comprising the following steps: (a) infusing hydrogen into hollow spheres which have gas-permeable walls, wherein the spheres comprise a polymer which (i) has a tensile strength sufficient to contain hydrogen under selected internal pressure conditions; and (ii) has a permeation coefficient which can be adjusted under variable humidity conditions; and then (b) adjusting the humidity level so that the walls of the spheres become substantially impermeable to hydrogen, so as to prevent the release of hydrogen from the spheres. 2. The method of claim 1, wherein the spheres have an average outside diameter in the range of about 50 microns to about 1,000 microns. 3. The method of claim 1, wherein the spheres have an average wall thickness of about 0.5 micron to about 20 microns. 4. The method of claim 1, wherein the humidity level is adjusted to less than about 1% relative humidity in step (b). 5. The method of claim 1, wherein the hydrogen is infused through the walls of the hollow spheres by subjecting the spheres to a humidity level of at least about 70% relative humidity, in a chamber which comprises hydrogen. 6. The method of claim 5, wherein the humidity level is at least about 80% relative humidity. 7. The method of claim 5, wherein the pressure in the chamber is at least about 100 atmospheres. 8. The method of claim 5, wherein the temperature in the chamber during step (a) is at least as high as the Tg of the polymer forming the spheres; and less than the decomposition temperature of the polymer. 9. The method of claim 1, wherein the polymer for the hollow spheres has a tensile strength sufficient to contain hydrogen at a pressure of at least about 3,000 psi. 10. The method of claim 1, wherein the polymer is selected from the group consisting of polyvinyl alcohols; carbohydrates; polyacrylonitrile; polyamines; combinations of any of the foregoing; and derivatives of any of the foregoing. 11. The method of claim 1, wherein the polymer is selected from the group consisting of polyvinyl alcohol; copolymers derived from polyvinyl alcohol; and blends containing polyvinyl alcohol. 12. The method of claim 11, wherein the polymer is a polyvinyl alcohol derivative selected from the group consisting of polyvinyl aceral, polyvinyl butyral, ethylene-vinyl alcohol (EVOH) copolymers, and combinations thereof. 13. The method of claim 10, wherein the carbohydrate comprises a polysaccharide polymer. 14. The method of claim 13, wherein the polysaccharide polymer is selected from the group consisting of cellulose polymers, starch polymers, and combinations thereof. 15. The method of claim 1, wherein the hollow spheres are made from a technique selected from the group consisting of spray drying and droplet generation. 16. The method of claim 1, further comprising the step of releasing a selected amount of the hydrogen in the spheres at a selected time after step (b), by subjecting the spheres to a humidity level sufficient to make the walls of the spheres permeable to the passage of the selected amount of hydrogen. 17. The method of claim 1, further comprising the step of releasing a selected amount of the hydrogen in the spheres at a selected time after step (b), by fracturing or perforating at least a portion of the spheres. 18. The method of claim 17, wherein the hollow spheres are perforated by a compression technique. 19. The method of claim 1, further comprising the step of releasing a selected amount of the hydrogen from the spheres at a selected time after step (b), by combusting the spheres. 20. The method of claim 1, further comprising the steps of releasing a selected amount of the hydrogen from the spheres at a selected time after step (b), and directing the released hydrogen to at least one hydrogen-consuming system selected from the group consisting of fuel cells; turbine engines; internal combustion engines; chemical process operations, and combinations thereof. 21. A method for storing and releasing hydrogen, comprising the following steps: (I) infusing hydrogen into hollow spheres which have gas-permeable walls, wherein the spheres comprise a polyvinyl polymer or derivative thereof; and the infusion is carried Out under humidity conditions sufficient to make the walls of the spheres permeable to the passage of hydrogen; (II) storing the hydrogen within the hollow spheres by lowering the humidity level, so that the walls of the spheres become substantially impermeable to hydrogen; and (III) releasing a selected amount of the hydrogen from the spheres at a selected time after step (II), by increasing the humidity surrounding the spheres, and directing the released hydrogen to at least one hydrogen-consuming system selected from the group consisting of fuel cells; turbine engines; internal combustion engines; chemical process operations, and combinations thereof. 22. The method of claim 21, wherein the hydrogen is stored in the spheres at a pressure in the range of about 3,000 psi to about 10,000 psi. 23. The method of claim 21, wherein the spheres have an average outside diameter in the range of about 50 micron to about 1,000 microns; and an average wall thickness of about 0.5 micron to about 20 microns; and are made from a spray drying or droplet-generation process. 24. A collection of hollow polymeric spheres, comprising a polymer selected from the group consisting of polyvinyl alcohols; carbohydrates; polyacrylonitrile; polyamines; combinations of any of the foregoing; and derivatives of any of the foregoing, wherein the polymeric spheres have an average diameter in the range of about 50 microns to about 1,000 microns, and the interior of the spheres comprises hydrogen gas at a pressure of at least about 3,000 psi. 25. A storage container, comprising the collection of hollow polymeric spheres recited in claim 24. 26. An apparatus for storing and delivering hydrogen, comprising: (A) a hydrogen source; (B) a collection of hollow polymeric spheres, comprising a polymer selected from the group consisting of polyvinyl alcohols; carbohydrates; polyacrylonitrile; polyamines; combinations of any of the foregoing; and derivatives of any of the foregoing, wherein the polymeric spheres have an average diameter in the range of about 50 microns to about 1,000 microns, and the spheres are capable of containing hydrogen gas at a pressure of at least about 3,000 psi; (C) a chamber which contains the polymeric spheres and which is capable of allowing them to be exposed to variable conditions of humidity, heat, and pressure; wherein adjustments of humidity alter the permeability of the spheres to hydrogen, to allow for hydrogen storage or hydrogen release through the walls of the sphere; and (D) means for directing the released hydrogen to a hydrogen destination. 27. The apparatus of claim 26, wherein the chamber of element (C) comprises an autoclave. 28. The apparatus of claim 26, wherein element (D) comprises a conduit system through which the hydrogen can pass. 29. The apparatus of claim 26, wherein the means for releasing hydrogen from the spheres according to element (C) comprises equipment for changing the humidity surrounding the spheres. 30. The apparatus of claim 26, further comprising at least one additional means for releasing hydrogen from the spheres, selected from the group consisting of equipment for fracturing or perforating the spheres; and equipment for combusting the spheres.