Liquid metal condensate catalyzed hydrocarbon pyrolysis

1. A method comprising:

evaporating a catalyst source to produce a catalyst gas, wherein the catalyst source comprises a catalyst and the evaporation step is performed by a catalyst source evaporator; subsequently

introducing the catalyst gas into a reactor;

condensing the catalyst gas in the reactor to produce a catalyst vapor comprising catalyst droplets suspended in a gas phase;

introducing a hydrocarbon gas to the reactor downstream of the catalyst gas introduction to the reactor; and

contacting the catalyst vapor with a hydrocarbon gas so as to catalyze a decomposition reaction of the hydrocarbon gas into hydrogen gas and carbon.

2. The method of claim 1 further comprising:

collecting the catalyst droplets to produce a mixture of the carbon and a catalyst liquid; and separating the carbon from the catalyst liquid.

3. The method of claim 2 , wherein separating the carbon from the catalyst liquid comprises:

evaporating the catalyst liquid from the carbon.

4. The method of claim 2 further comprising:

recycling the catalyst liquid to the catalyst source for evaporation.

5. The method of claim 1 further comprising:

condensing the catalyst droplets to produce a mixture of the carbon and a catalyst liquid;

recycling the mixture to the catalyst source for evaporation; and

separating the carbon from the catalyst source.

6. The method of claim 1 , wherein the catalyst gas before condensation is at a temperature of about 5° C. to about 500° C. greater than a boiling point of the catalyst.

7. The method of claim 1 , wherein condensing the catalyst gas comprises:

exposing the catalyst gas to the hydrocarbon gas, wherein the hydrocarbon gas is at a temperature below a boiling point of the catalyst.

8. The method of claim 7 , wherein the temperature of the hydrocarbon gas is about 5° C. to about 500° C. less than a boiling point of the catalyst.

9. The method of claim 1 , wherein the catalyst is a metal.

10. The method of claim 9 , wherein the metal has a boiling point of 1,500° C. or less.

11. The method of claim 1 , wherein the catalyst is a salt.

12. The method of claim 1 , wherein the catalyst is an ionic liquid.

13. The method of claim 1 , wherein the catalyst droplets have a diameter of about 5 nm to about 10,000 nm.

14. The method of claim 1 , wherein the catalyst droplets have a diameter of about 5 nm to about 150 nm.

15. The method of claim 1 , wherein the catalyst vapor comprises the catalyst droplets such that about 60 vol % or less of the catalyst vapor is the catalyst droplets.

16. The method of claim 1 , wherein the catalyst vapor has a catalytic areal density of about 1,000 m 2 /m 3 to about 30,000 m 2 /m 3 .

17. The method of claim 1 , wherein the hydrocarbon gas comprises one or more selected from the group consisting of:

a C1 to C20 alkane, a C1 to C20 alkene, a C1 to C20 alkynes, and a C6 to C20 arene.

18. The method of claim 1 , wherein the gas phase comprises 0 vol % to about 1 vol % of oxygen-containing compounds that are reactive in the decomposition reaction to produce carbon dioxide.

19. A system comprising:

a catalyst source evaporator coupled to a reactor via a first stream comprising catalyst gas such that the reactor receives the first stream from the catalyst source evaporator;

a hydrocarbon source coupled to the reactor via a second stream comprising hydrocarbon gas such that the reactor receives the second stream from the hydrocarbon source downstream of the first stream;

a cooling column coupled to the reactor via a third stream comprising hydrogen, catalyst liquid, solid carbon, optionally catalyst gas, and optionally unreacted hydrocarbon gas such that the cooling column receives the third stream from the reactor; and

wherein the cooling column has effluent streams that include (a) a fourth stream that comprises hydrogen and optionally catalyst gas and (b) a fifth stream that comprises catalyst liquid.