Hydrogen production methods and related systems and compositions
A method of producing hydrogen may include: providing a catalyst-carbon gel; and flowing a hydrocarbon through a catalyst, wherein catalyst is a metal or mixture of metals that is non-wetting to solid carbon at 1 bar absolute and 10° C. above a melting point of the metal or mixture of metals.
1. A method comprising:
providing a catalyst-carbon gel; and
flowing a hydrocarbon through the catalyst-carbon gel under conditions sufficient to pyrolyze the hydrocarbon, wherein a catalyst of the catalyst-carbon gel is a metal or mixture of metals that is non-wetting to solid carbon at 1 bar absolute and 10° C. above a melting point of the metal or mixture of metals.
2. The method of claim 1 , wherein the catalyst-carbon gel comprises (a) a plurality of catalyst particles at least partially coated with a solid carbon coating and (b) solid carbon not contacting portions of the plurality of catalyst particles and not being part of the solid carbon coating.
3. The method of claim 2 , wherein the catalyst particles of the catalyst-carbon gel have a D90 of about 10 μm or less.
4. The method of claim 2 , wherein the catalyst particles of the catalyst-carbon gel have a D10 of about 0.1 μm or more.
5. The method of claim 1 further comprising:
flowing the hydrocarbon through a second catalyst comprising the catalyst, wherein the second catalyst is upstream of and separate from the catalyst-carbon gel.
6. The method of claim 5 , wherein the hydrocarbon through the second catalyst is at a flow rate sufficient to achieve at a linear velocity immediately downstream of the second catalyst of about 0.1 cm/s to about 1 m/s.
7. The method of claim 1 , wherein the hydrocarbon has present water and oxygen, individually, at 10 ppm or less.
8. The method of claim 1 , wherein the hydrocarbon contains neither water nor oxygen.
9. The method of claim 1 , wherein the metal or mixture of metals comprises one or more of: potassium, sodium, selenium, cadmium, zinc, or magnesium.
10. The method of claim 1 further comprising:
downstream of the catalyst-carbon gel separating hydrogen and unreacted hydrocarbons.
11. The method of claim 1 further comprising:
mechanically removing solid carbon from the catalyst-carbon gel.
12. The method of claim 1 further comprising:
cooling the catalyst-carbon gel; and
chemically and/or thermally removing the catalyst from the catalyst-carbon gel.
13. The method of claim 1 , wherein a temperature at the catalyst-carbon gel is at a melting point of the catalyst to 10° C. below a boiling point of the catalyst at a working pressure of the catalyst-carbon gel.
14. The method of claim 1 , wherein a temperature at the catalyst-carbon gel is about 750° C. to about 1250° C. and a pressure at the catalyst-carbon gel is about 1bar absolute to about 10 bars absolute.
15. The method of claim 1 , wherein the hydrocarbon comprises methane.