Method for loading and storing gas in nano-valved sorbents

1. A method for loading and storing gas, comprising the steps of:

providing adsorbent pellets coated with a nano-porous outer layer, the nano-porous outer layer including nano-valves capable of being opened and closed on demand;

loading the adsorbent pellets with gas at a loading pressure when the nano-valves are opened, forming loaded nano-valved adsorbent pellets;

closing the nano-valves in the loaded nano-valved adsorbent pellets; and

storing the loaded nano-valved adsorbent pellets at a storage pressure that is lower than the loading pressure.

2. The method of claim 1 , wherein the step of closing the nano-valves comprises the step of sealing the nano-porous outer layer with an adsorbate.

3. The method of claim 2 , wherein the adsorbate comprises ethanol or a hydrocarbon.

4. The method of claim 1 , wherein the loaded nano-valved adsorbent pellets have an internal pressure that is higher than the storage pressure, and the closed nano-valves maintain a pressure differential between the internal pressure and the storage pressure.

5. The method of claim 1 , further comprising the step of opening the closed nano-valves to release the gas from the loaded nano-valved adsorbent pellets.

6. The method of claim 1 , wherein the adsorbent pellets comprise a zeolite.

7. The method of claim 1 , wherein the adsorbent pellets comprise a carbon-based material.

8. The method of claim 1 , wherein the adsorbent pellets comprise a metal-organic framework.

9. The method of claim 1 , wherein the adsorbent pellets comprise a covalent-organic framework.

10. The method of claim 1 , wherein the nano-porous outer layer has an average pore size of about 0.3 nanometers to about 1 nanometer.

11. The method of claim 4 , wherein the pressure differential is at least about 50 bar.

12. The method of claim 1 , wherein the loading pressure is at least about 250 bar.

13. The method of claim 12 , wherein the storage pressure is about 35 bar or less.

14. The method of claim 1 , wherein the loaded nano-valved adsorbent pellets are stored in one or more conformable cartridge-type tanks.

15. A method for storing and releasing gas, comprising the steps of:

providing loaded nano-valved adsorbent pellets including a nano-porous outer layer and loaded with gas, the nano-porous outer layer including nano-valves capable of being opened and closed on demand;

storing the loaded nano-valved adsorbent pellets with the nano-valves being closed; and

opening the nano-valves to release the gas.

16. The method of claim 15 , wherein the nano-valves are maintained in a closed position by sealing the nano-porous outer layer with an adsorbate.

17. The method of claim 16 , wherein the nano-porous outer layer comprises pores having an average diameter of about 0.3 nanometers to about 1 nanometer.

18. The method of claim 17 , wherein the adsorbate comprises liquid molecules having a kinetic diameter of about 0.3 nanometers to about 1 nanometer.

19. The method of claim 15 , wherein the step of opening the nano-valves comprises heating the nano-porous outer layer to a temperature of about 55° C. to about 85° C.

20. The method of claim 15 , wherein the adsorbent pellets comprise a zeolite, a carbon-based material, a metal-organic framework, a covalent-organic framework, or a combination thereof.

21. The method of claim 15 , wherein the nano-valves are maintained in a closed position by sealing with a liquid, and the step of opening the nano-valves comprises the step of vaporizing the liquid.

22. A system for on-board storage of gas, comprising:

a storage tank including a plurality of zones;

loaded nano-valved adsorbent pellets including a nano-porous outer layer in the zones, the nano-porous outer layer including nano-valves capable of being opened and closed on demand;

gas stored in the loaded the nano-valved adsorbent pellets in one or more of the plurality of zones, the nano-valves on the loaded nano-valved adsorbent pellets being maintained in a closed position; and

a thermal management system capable of independently heating each of the plurality of zones to open the nano-valves and release gas from the loaded nano-valved adsorbent pellets in the zone.

23. The system of claim 22 , further comprising a gas transfer unit for loading gas under pressure into each of the plurality of zones.

24. The system of claim 23 , wherein the gas transfer unit comprises apparatus for transferring loaded nano-valved adsorbent pellets into one or more of the plurality of zones.

25. The system of claim 24 , wherein the gas transfer unit comprises one or more cartridges, each one including a plurality of nano-valved adsorbent pellets, which can be manually transferred back and forth between a vehicle and a charging tank.

26. A method for loading and storing gas, comprising the steps of:

providing adsorbent pellets coated with a nano-porous outer layer, the nano-porous outer layer including nano-valves capable of being opened and closed on demand;

storing the adsorbent pellets in one or more cartridge-type tanks, each tank containing a plurality of the adsorbent pellets;

loading the adsorbent pellets in the cartridges with gas at a loading pressure when the nano-valves are opened, forming loaded nano-valved adsorbent pellets in the cartridges;

closing the nano-valves in the loaded nano-valved adsorbent pellets; and

storing the cartridges containing the loaded nano-valved adsorbent pellets at a storage pressure that is lower than the loading pressure.