Process for converting a natural gas feedstock with inert content to chemical intermediates

1. A methane conversion process for producing C 2+ hydrocarbons comprising:

(a) introducing a reactant mixture to a reaction unit to produce a reactor effluent stream; wherein the reactant mixture comprises methane and an inert compound; wherein the methane is present in the reactant mixture in a concentration of equal to or greater than about 20 mol %; wherein the reactor effluent stream comprises C 2+ hydrocarbons, methane, the inert compound, and water and/or carbon dioxide; and wherein the mole fraction of methane in the reactant mixture is greater than the mole fraction of methane in the reactor effluent stream;

(b) removing at least a portion of the water and/or at least a portion of the carbon dioxide from the reactor effluent stream to produce a demethanizer feed stream;

(c) feeding at least a portion of the demethanizer feed stream to a demethanizer unit to produce two or more vapor streams, and at least one liquid stream; wherein the two or more vapor streams comprise a methane rich stream and an inert rich stream; wherein the mole fraction of methane in the methane rich stream is greater than the mole fraction of methane in the inert rich stream; wherein the mole fraction of inert compound in the inert rich stream is greater than the mole fraction of inert compound in the methane rich stream; and wherein the at least one liquid stream comprises C 2+ hydrocarbons;

(d) withdrawing at least a portion of the inert rich stream as a purge stream;

(e) recycling any remaining portion of the inert rich stream to the reaction unit; and

(f) recycling the methane rich stream to the reaction unit.

2. The methane conversion process of claim 1 further comprising (i) combining the methane rich stream with the remaining portion of the inert rich stream to produce a methane recycle stream; and (ii) recycling the methane recycle stream to the reaction unit.

3. The methane conversion process of claim 1 , wherein the two or more vapor streams comprise a methane rich stream and a plurality of inert rich streams.

4. The methane conversion process of claim 3 , wherein two or more inert rich streams of the plurality of inert rich streams are combined to form a combined inert rich stream.

5. The methane conversion process of claim 4 further comprising (i) withdrawing at least a portion of the combined inert rich stream as a purge stream; and (ii) recycling any remaining portion of the combined inert rich stream to the reaction unit.

6. The methane conversion process of claim 4 further comprising (1) withdrawing at least a portion of at least one inert rich stream of the two or more inert rich streams as a purge stream prior to forming the combined inert rich stream; and (2) recycling the combined inert rich stream to the reaction unit.

7. The methane conversion process of claim 1 , wherein the reactor effluent stream further comprises hydrogen.

8. The methane conversion process of claim 7 further comprising (i) feeding at least a portion of the inert rich stream to a hydrogen recovery unit to produce a hydrogen rich stream and a hydrogen lean stream, wherein the mole fraction of hydrogen in the hydrogen rich stream is greater than the mole fraction of hydrogen in the hydrogen lean stream; (ii) withdrawing at least a portion of the hydrogen lean stream as a purge stream; and (iii) recycling any remaining portion of the hydrogen lean stream to the reaction unit.

9. The methane conversion process of claim 1 , wherein a feed stream comprising supplemental methane is introduced to the reaction unit; the demethanizer unit; a carbon dioxide removal unit located upstream of the demethanizer unit; or combinations thereof.

10. The methane conversion process of claim 9 , wherein the feed stream comprising supplemental methane comprises the inert compound in a mole fraction of equal to or greater than about 0.001.

11. The methane conversion process of claim 1 further comprising recovering C 2+ olefins and/or C 2+ alkanes from the at least one liquid stream in a downstream separation unit.

12. The methane conversion process of claim 1 , wherein the temperature of the inert rich stream is increased by indirect heat exchange with at least one process stream prior to the step (d) of withdrawing at least a portion of the inert rich stream as a purge stream.

13. The methane conversion process of claim 12 , wherein the at least one process stream comprises the demethanizer feed stream.

14. The methane conversion process of claim 1 , wherein the methane conversion process comprises oxidative coupling of methane, a single-step methane to olefins conversion, methanation, thermal cracking, ethane pyrolysis, or combinations thereof.

15. The methane conversion process of claim 1 , wherein the demethanizer unit comprises one or more flash vessels and at least one fractionation column; wherein the inert rich stream is recovered as an overhead stream from the one or more flash vessels; wherein the methane rich stream is recovered as an overhead stream from the fractionation column; and wherein the at least one liquid stream is recovered as a bottoms stream from the fractionation column.

16. The methane conversion process of claim 1 , wherein the inert compound is nitrogen (N 2 ).

17. A process for producing olefins comprising:

(a) introducing a reactant mixture to an oxidative coupling of methane (OCM) reaction unit to produce a reactor effluent stream; wherein the reactant mixture comprises methane, oxygen (O 2 ), and an inert compound; wherein the methane is present in the reactant mixture in a concentration of equal to or greater than about 40 mol %; wherein the reactor effluent stream comprises C 2+ olefins, methane, hydrogen (H 2 ), the inert compound, water, and carbon dioxide; and wherein the mole fraction of methane in the reactant mixture is greater than the mole fraction of methane in the reactor effluent stream;

(b) removing at least a portion of the water and/or at least a portion of the carbon dioxide from the reactor effluent stream to produce a demethanizer feed stream;

(c) feeding at least a portion of the demethanizer feed stream to a demethanizer unit to produce two or more vapor streams, and at least one liquid stream; wherein the two or more vapor streams comprise a methane rich stream and an inert rich stream; wherein the mole fraction of methane in the methane rich stream is greater than the mole fraction of methane in the inert rich stream; wherein the mole fraction of inert compound in the inert rich stream is greater than the mole fraction of inert compound in the methane rich stream; and wherein the at least one liquid stream comprises C 2+ olefins;

(d) withdrawing at least a portion of the inert rich stream as a purge stream;

(e) recycling any remaining portion of the inert rich stream to the OCM reaction unit; and

(f) recycling the methane rich stream to the OCM reaction unit.

18. The process of claim 17 further comprising (i) feeding at least a portion of the inert rich stream to a hydrogen recovery unit to produce a hydrogen rich stream and a hydrogen lean stream, wherein the mole fraction of hydrogen in the hydrogen rich stream is greater than the mole fraction of hydrogen in the hydrogen lean stream; (ii) withdrawing at least a portion of the hydrogen lean stream as a purge stream; and (iii) recycling any remaining portion of the hydrogen lean stream to the OCM reaction unit.

19. The process of claim 17 further comprising recovering C 2+ olefins from the at least one liquid stream in a downstream separation unit; wherein the C 2+ olefins comprise ethylene and propylene.

20. The process of claim 17 further comprising recovering C 2+ alkanes from the at least one liquid stream in a downstream separation unit; wherein the C 2+ alkanes comprise ethane; and wherein at least a portion of the C 2+ alkanes is recycled to the OCM reaction unit.