Sour NGL stream recovery

1. A method comprising:

receiving a feed stream at a first separator, wherein the feed stream comprises heavy hydrocarbons, carbon dioxide, H 2 S, and C 3+ hydrocarbons;

separating the feed stream in the first separator into a heavy hydrocarbon stream and a carbon dioxide recycle stream, wherein the heavy hydrocarbon stream comprises the heavy hydrocarbons, and wherein the carbon dioxide recycle stream comprises the carbon dioxide, the H 2 S, and the C 3+ hydrocarbons;

receiving the carbon dioxide recycle stream at a second separator;

separating the carbon dioxide recycle stream in the second separator into a purified carbon dioxide recycle stream and a natural gas liquids stream, wherein the purified carbon dioxide recycle stream comprises the carbon dioxide, and wherein the natural gas liquids stream comprises the H 2 S and a portion of the C 3+ hydrocarbons from the carbon dioxide recycle stream;

receiving the natural gas liquids stream at a third separator;

separating the natural gas liquids stream in the third separator into a light natural gas liquids stream and a heavy natural gas liquids stream; and

combining the heavy hydrocarbon stream from the first separator with the heavy natural gas liquids stream from the third separator, wherein the heavy hydrocarbon stream comprises C 9+ hydrocarbons, aromatic hydrocarbons, and branched hydrocarbons, and wherein the heavy natural gas liquids stream comprises C 3 -C 8 hydrocarbons.

2. The method according to claim 1 , further comprising separating the natural gas liquids stream into a rich natural gas liquids stream and an acid gas stream, wherein the acid gas stream comprises the H 2 S.

3. The method according to claim 1 , wherein the carbon dioxide recycle stream comprises methane and ethane, and wherein at least 99 molar % of the methane and the ethane is separated from the carbon dioxide recycle stream into the purified carbon dioxide recycle stream.

4. The method according to claim 1 , wherein separating the carbon dioxide recycle stream in the second separator comprises using a three-phase separator to separate the carbon dioxide recycle stream into a vapor stream, an organic liquid stream, and an aqueous liquid stream.

5. The method according to claim 1 , wherein receiving the carbon dioxide recycle stream at the second separator comprises receiving streams comprising natural gas liquids from a plurality of different natural gas liquid sources.

6. The method according to claim 1 , wherein separating the carbon dioxide recycle stream in the second separator into the purified carbon dioxide recycle stream and the natural gas liquids stream consists essentially of:

receiving the carbon dioxide recycle stream at a separation column;

reboiling a portion of the carbon dioxide recycle stream received from the separation column with a reboiler to generate the natural gas liquids stream; and

condensing another portion of the carbon dioxide recycle stream received from the separation column with a condenser to generate the purified carbon dioxide recycle stream.

7. The method according to claim 1 , wherein the natural gas liquids stream comprises 20 molar % to 35 molar % of the C 3+ hydrocarbons from the carbon dioxide recycle stream.

8. The method according to claim 1 , wherein the natural gas liquids stream comprises 40 molar % to 65 molar % of the C 3+ hydrocarbons from the carbon dioxide recycle stream.

9. The method according to claim 1 , wherein the natural gas liquids stream comprises 70 molar % to less than 90 molar % of the C 3+ hydrocarbons from the carbon dioxide recycle stream.

10. The method according to claim 1 , wherein the first separator comprises a phase separator, and wherein the second separator and the third separator comprise distillation columns.

11. The method according to claim 1 , wherein after the heavy hydrocarbon stream from the first separator is combined with the heavy natural gas liquids stream from the third separator, the combined stream is sent to a pipeline for transportation.

12. The method according to claim 1 , wherein after the heavy hydrocarbon stream from the first separator is combined with the heavy natural gas liquids stream from the third separator, the combined stream is sent to a storage tank.

13. The method according to claim 1 , further comprising dehydrating the carbon dioxide recycle stream from the first separator before passing the carbon dioxide recycle stream to the second separator.

14. The method according to claim 13 , wherein the carbon dioxide recycle stream is dehydrated in a plurality of dehydrators that are arranged in series.

15. The method according to claim 13 , wherein the carbon dioxide recycle stream is dehydrated in a plurality of dehydrators that are arranged in parallel.

16. A system comprising:

a first separator configured to receive a feed stream and to separate the feed stream into a heavy hydrocarbons stream and a recycle stream, wherein the feed stream comprises heavy hydrocarbons, injection gas, H 2 S, and C 3+ hydrocarbons, wherein the heavy hydrocarbon stream comprises the heavy hydrocarbons, and wherein the recycle stream comprises the injection gas, the H 2 S, and the C 3+ hydrocarbons;

piping configured to receive the recycle stream;

a second separator coupled to the piping and configured to separate the recycle stream into a purified recycle stream and a natural gas liquids stream, wherein the purified recycle stream comprises the injection gas, and wherein the natural gas liquids stream comprises the H 2 S and a portion of the C 3+ hydrocarbons from the recycle stream;

a third separator configured to receive the natural gas liquids stream and to separate the natural gas liquids stream into a light natural gas liquids stream and a heavy natural gas liquids stream; and

additional piping configured to receive and combine the heavy hydrocarbon stream from the first separator and the heavy natural gas liquids stream from the third separator, wherein the heavy hydrocarbon stream comprises C 9+ hydrocarbons, aromatic hydrocarbons, and branched hydrocarbons, and wherein the heavy natural gas liquids stream comprises C 3 -C 8 hydrocarbons.

17. The system according to claim 16 , wherein the system is further configured to separate the natural gas liquids stream into a sweetened natural gas liquids stream and an acid gas stream, wherein the acid gas stream comprises the H 2 S.

18. The system according to claim 16 , wherein the system is further configured to dehydrate the recycle stream and cool the recycle stream using the purified recycle stream.

19. The system according to claim 16 , wherein the second separator comprises a three-phase separator that is configured to separate the recycle stream into a vapor stream, an organic liquid stream, and an aqueous liquid stream.

20. The system according to claim 16 , wherein the piping is configured to receive streams comprising natural gas liquids from a plurality of different natural gas liquid sources.

21. The system according to claim 16 , wherein the second separator consists essentially of a separation column, a reboiler, and a condenser, wherein the separation column receives the recycle stream, wherein the reboiler receives a first portion of the recycle stream from the separation column and generates the natural gas liquids stream, and wherein the condenser receives a second portion of the recycle stream from the separation column and generates the purified recycle stream.

22. The system according to claim 16 , wherein the natural gas liquids stream comprises 20 molar % to 35 molar % of the C 3+ hydrocarbons from the recycle stream.

23. The system according to claim 16 , wherein the natural gas liquids stream comprises 40 molar % to 65 molar % of the C 3+ hydrocarbons from the recycle stream.

24. The system according to claim 16 , wherein the natural gas liquids stream comprises 70 molar % to less than 90 molar % of the C 3+ hydrocarbons from the recycle stream.

25. A set of process equipment comprising:

a first separator configured to receive a feed stream and to separate the feed stream into a heavy hydrocarbons stream and a recycle stream, wherein the feed stream comprises heavy hydrocarbons, injection gas, H 2 S, and C 3+ hydrocarbons, wherein the heavy hydrocarbon stream comprises the heavy hydrocarbons, and wherein the recycle stream comprises the injection gas, the H 2 S, and the C 3+ hydrocarbons;

an input line configured to receive the recycle stream;

a second separator configured to receive the recycle stream from the input line and separate the recycle stream into a purified recycle stream and a natural gas liquids stream;

a first output line configured to output the purified recycle stream from the second separator, wherein the purified recycle stream comprises the injection gas;

a second output line configured to output the natural gas liquids stream from the second separator, wherein the natural gas liquids stream comprises the H 2 S and a portion of the C 3+ hydrocarbons from the recycle stream;

a third separator configured to receive the natural gas liquids stream from the second output line and to separate the natural gas liquids stream into a light natural gas liquids stream and a heavy natural gas liquids stream; and

an additional line configured to receive and combine the heavy hydrocarbon stream from the first separator and the heavy natural gas liquids stream from the third separator, wherein the heavy hydrocarbon stream comprises C 9+ hydrocarbons, aromatic hydrocarbons, and branched hydrocarbons, and wherein the heavy natural gas liquids stream comprises C 3 -C 8 hydrocarbons.

26. The set of process equipment according to claim 25 , wherein the second separator comprises a three-phase separator that is configured to separate the recycle stream into a vapor stream, an organic liquid stream, and an aqueous liquid stream.

27. The set of process equipment according to claim 25 , wherein the input line is configured to receive streams comprising natural gas liquids from a plurality of different natural gas liquid sources.

28. The set of process equipment according to claim 25 , further comprising an injection gas makeup line configured to add additional injection gas to the purified recycle stream, wherein the additional injection gas comprises at least one of carbon dioxide, nitrogen, methane, ethane, air, and water.

29. The set of process equipment according to claim 25 , further comprising one or more compressors configured to increase a pressure of the recycle stream before entering the second separator and increase a pressure of the purified recycle stream after leaving the second separator.

30. The set of process equipment according to claim 25 , wherein the second separator consists essentially of a separation column, a reboiler, and a condenser, wherein the separation column receives the recycle stream, wherein the reboiler receives a first portion of the recycle stream from the separation column and generates the natural gas liquids stream, and wherein the condenser receives a second portion of the recycle stream from the separation column and generates the purified recycle stream.

31. The system according to claim 25 , wherein the natural gas liquids stream comprises 20 molar % to 35 molar % of the C 3+ hydrocarbons from the recycle stream.

32. The system according to claim 25 , wherein the natural gas liquids stream comprises 40 molar % to 65 molar % of the C 3+ hydrocarbons from the recycle stream.

33. The system according to claim 25 , wherein the natural gas liquids stream comprises 70 molar % to less than 90 molar % of the C 3+ hydrocarbons from the recycle stream.