Hydrogen generation with efficient byproduct recycle
View Patent ↗Methods and systems for generating hydrogen gas from methane are disclosed. In one embodiment, a method includes heating a vessel containing a catalyst to a temperature above approximately 600° centigrade and pressurizing the vessel to about ten atmospheres. A pressure swing absorbent, a methane stream, and a stream of steam are introduced into the vessel. In a particular aspect, the temperature may be maintained within a range of approximately 600 C. to approximately 700 C.
1. A method for generating hydrogen gas from a methane, the method comprising:
heating a vessel containing a catalyst to a temperature within a range of approximately 600° centigrade to approximately 700° centigrade;
pressurizing the vessel to about ten atmospheres;
introducing a pressure swing absorbent into the vessel; introducing a methane stream into the heated and pressurized vessel containing the absorbent; and
introducing a stream of steam into the heated and pressurized vessel containing the absorbent.
2. The method of claim 1 , wherein the pressure swing absorbent includes calcium oxide.
3. The method of claim 2 , wherein the calcium oxide is introduced at twice a stoichiometric ratio.
4. The method of claim 1 , wherein the steam is introduced in a steam to carbon ratio of about four.
5. The method of claim 1 , further including venting a product gas from the vessel.
6. The method of claim 5 , wherein the product gas is substantially hydrogen.
7. The method of claim 1 , further including venting a by-product gas from the vessel.
8. The method of claim 7 , wherein the by-product gas is substantially methane.
9. The method of claim 7 , wherein the by-product gas is recycled as a feedstock.
10. The method of claim 7 , wherein the by-product gas is recycled as a fuel for heating the vessel.
11. A method for steam reformation of methane, the method comprising:
introducing a pressure swing absorbent into a vessel, the vessel being configured to steam reform the hydrocarbon gas;
maintaining a pressure within the vessel, the pressure being about ten atmospheres; and
maintaining a temperature within the vessel, the temperature being within a range of approximately 600° centigrade to approximately 700° centigrade;
introducing a methane stream into the heated and pressurized vessel containing the absorbent; and
introducing a stream of steam into the heated and pressurized vessel containing the absorbent.
12. The method of claim 11 , wherein the pressure swing absorbent includes calcium oxide.
13. The method of claim 11 , wherein the calcium oxide is introduced at twice a stoichiometric ratio.
14. The method of claim 11 , wherein the steam is introduced in a steam to carbon ratio of about four.
15. The method of claim 11 , further including venting a product gas from the vessel.
16. The method of claim 15 , wherein the product gas is substantially hydrogen.
17. The method of claim 15 , further including venting a by-product gas from the vessel.
18. The method of claim 17 , wherein the by-product gas is substantially methane.
19. The method of claim 17 , wherein the by-product gas is recycled as a feedstock.
20. The method of claim 17 , wherein the by-product gas is recycled as a fuel for heating the vessel.