Oxidative coupling of methane systems and methods
Systems and methods conducive to the formation of one or more alkene hydrocarbons using a methane source and an oxidant in an oxidative coupling of methane (OCM) reaction are provided. One or more vessels each containing one or more catalyst beds containing one or more catalysts each having similar or differing chemical composition or physical form may be used. The one or more catalyst beds may be operated under a variety of conditions. At least a portion of the catalyst beds may be operated under substantially adiabatic conditions. At least a portion of the catalyst beds may be operated under substantially isothermal conditions.
1. A method of controlling the production of alkene hydrocarbons generated by the exothermic reaction of methane from a methane source and oxygen from an oxidant source over an oxidative coupling of methane (OCM) catalyst bed to provide an OCM gas comprising the alkene hydrocarbons, the method comprising:
monitoring a temperature of the OCM catalyst bed during production of the OCM gas, wherein said OCM catalyst bed comprises at least one nanostructure catalyst;
identifying a deviation in a maximum temperature of the OCM catalyst bed, which deviation is to a temperature that is above or below said maximum temperature; and
responsive to said deviation, performing at least one of the following:
(i) adjusting a quantity of the methane over the OCM catalyst bed;
(ii) adjusting a quantity of the oxygen over the OCM catalyst bed;
(iii) adjusting a proportion between a quantity of the oxygen and a quantity of the methane over the OCM catalyst bed;
(iv) adjusting a temperature of the methane source; and
(v) adjusting a temperature of the oxidant source.
2. The method of claim 1 , wherein the temperature that is above or below said maximum temperature is greater than at least 800° C.
3. The method of claim 1 , further comprising conducting the production of the OCM gas with the OCM catalyst bed under substantially adiabatic conditions.
4. The method of claim 1 , further comprising conducting the production of the OCM gas at a selectivity for hydrocarbons having two or more carbon atoms (C 2+ hydrocarbons) of at least about 50%.
5. The method of claim 1 , further comprising maintaining the methane source at a temperature of at least about 400° C. using at least one heat transfer unit thermally coupled to the methane source.
6. The method of claim 1 , further comprising maintaining the methane source at a temperature of at most about 600° C. using at least one heat transfer unit thermally coupled to the methane source.
7. The method of claim 1 , further comprising maintaining the oxidant source at a temperature of at least about 400° C. using at least one heat transfer unit thermally coupled to the oxidant source.
8. The method of claim 1 , further comprising conducting the production of the OCM gas at a pressure of greater than about 15 pounds per square inch gauge (psig) in the OCM catalyst bed.
9. The method of claim 1 , further comprising conducting the production of the OCM gas at a pressure of less than about 150 pounds per square inch gauge (psig) in the OCM catalyst bed.
10. The method of claim 9 , further comprising conducting the production of the OCM gas at a pressure of less than about 100 pounds per square inch gauge (psig) in the OCM catalyst bed.
11. The method of claim 1 , further comprising adjusting a proportion between a concentration of the methane and a concentration of the oxygen to provide a ratio between the methane and the oxygen over the OCM catalyst bed such that the oxidant acts as a limiting reagent.
12. The method of claim 1 , wherein the monitoring is conducted using a temperature sensor positioned within the OCM catalyst bed.
13. The method of claim 1 , wherein the OCM catalyst bed comprises at least one nanostructure catalyst that is pressed or formed into at least one shape.
14. The method of claim 13 , wherein the at least one nanostructure catalyst is selected from the group consisting of a metal oxide, a metal hydroxide, a perovskite, a metal oxyhydroxide, a metal oxycarbonate, a metal carbonate, a metal element from any of Groups 1 through 7, a lanthanide, and an actinide.
15. The method of claim 13 , wherein the at least one nanostructure catalyst comprises at least one metal dopant.