Methods for producing a fuel gas stream

• US 9,964,034 B2
• Filed: 03/27/2015
• Issued: 05/08/2018
• Est. Priority Date: 04/09/2014
• Status: Active Grant

• Current Assignee: Exxonmobil Upstream Research Company (Exxon Mobil Corporation)
• Original Assignee: Exxonmobil Upstream Research Company (Exxon Mobil Corporation)
• Inventors: Denton, Robert D.
• Primary Examiner(s): Tran, Binh Q
• Application Number:
  US14/671,029
• Publication Number:
  US 20150292403A1
• Time in Patent Office: 1,138 Days
• Field of Search: 60 3902, 60 3906, 60 3912, 60 39465, 60 39461, 60645, 60683, 60723, 60772, 60775, 60781, 62612, 62313, 62614
• CPC Class Codes: C10L 3/103 Sulfur containing contaminants
• CPC Class Codes: C10L 3/104 Carbon dioxide
• CPC Class Codes: C10L 3/106 of water
• CPC Class Codes: F02C 3/20 using a special fuel, oxidant, or dilution fluid to generate the combustion products
• CPC Class Codes: F05D 2220/75 equipment using fuel having a low calorific value, e.g. low BTU fuel, waste end, syngas, biomass fuel or flare gas
• CPC Class Codes: F25J 2220/66 Separating acid gases, e.g. CO2, SO2, H2S or RSH
• CPC Class Codes: F25J 2230/08 Cold compressor, i.e. suction of the gas at cryogenic temperature and generally without afterstage-cooler
• CPC Class Codes: F25J 2230/32 Compression of the product stream
• CPC Class Codes: F25J 2240/02 Expansion of a process fluid in a work-extracting turbine (i.e. isentropic expansion), e.g. of the feed stream
• CPC Class Codes: F25J 2290/72 Processing device is used off-shore, e.g. on a platform or floating on a ship or barge
• CPC Class Codes: F25J 3/061 Natural gas or substitute natural gas
• CPC Class Codes: F25J 3/0635 separation of CnHm with 1 carbon atom or more
• CPC Class Codes: F25J 3/064 separation of CnHm with 2 carbon atoms or more

Abstract

Methods and systems for dynamically planning a well site are provided herein. Methods include flowing a raw gas stream though a suction scrubber to form a feed gas stream and compressing the feed gas stream to form a compressed gas stream. Methods include cooling the compressed gas stream in a cooler to produce a cooled gas stream. Methods include feeding the cooled gas stream into a gas treatment system, using a turboexpander, to produce a conditioned gas and a waste stream. Methods include heating the conditioned gas in a heat exchanger, where the conditioned gas is a superheated, sweetened, gas. Methods also include burning the conditioned gas in a turbine generator and mixing the waste stream into the raw gas stream upstream of the suction scrubber.

Claims

1. A method for producing a fuel gas stream, comprising:

flowing a raw gas stream through a suction scrubber to form a feed gas stream;

compressing the feed gas stream to form a compressed gas stream;

cooling the compressed gas stream in a cooler to produce a cooled gas stream;

feeding the cooled gas stream into a gas treatment system, using a turboexpander, to produce a conditioned gas and a waste stream;

heating the conditioned gas in a heat exchanger, wherein the conditioned gas is a superheated, sweetened gas;

burning the conditioned gas in a turbine generator; and

mixing the waste stream into the raw gas stream upstream of the suction scrubber.

2. The method of claim 1, comprising separating condensed liquids from a cooled gas stream to form a flash stream, wherein the flash stream is fed into a raw gas stream upstream of a suction scrubber.

3. The method of claim 1, comprising dehydrating a cooled gas stream, within a gas treatment system, to produce a dry gas stream and a waste water stream, wherein the waste water stream is fed into a raw gas stream upstream of a suction scrubber.

4. The method of claim 1, comprising feeding a portion of a cold vapor stream into a regeneration gas separator to produce a regeneration liquids stream and a regeneration gas stream, wherein the regeneration liquids stream is fed into the raw gas stream upstream of the suction scrubber.

5. The method of claim 1, comprising feeding a portion of a cold vapor stream into a cryogenic expander, wherein a contaminant rich liquid is produced.

6. The method of claim 1, comprising feeding a conditioned gas into a compressor before heating.

7. The method of claim 1, comprising pumping a waste stream into a raw gas stream upstream of a suction scrubber.

8. The method of claim 1, comprising heating a waste stream and a regeneration gas stream in a heat exchanger before entering a suction scrubber.

9. The method of claim 1, comprising heating a conditioned gas, a waste stream, and a regeneration gas stream in a cooling water loop after heating in a heat exchanger.

10. A system for producing a fuel gas stream, comprising

a suction scrubber to form a feed gas stream from a raw gas stream;

a compressor to form a compressed gas stream from the feed gas stream;

a cooling water system to cool the compressed gas stream to produce a cooled gas stream;

a gas treatment system, comprising an expansion device and a low temperature separation step, to remove contaminants from the cooled gas stream to produce a fuel gas and a waste stream, wherein the waste stream is mixed into the raw gas stream upstream of the suction scrubber;

a heat exchanger to superheat the fuel gas to produce a superheated, sweetened gas; and

a turbine generator to combust the superheated, sweetened gas.

11. The system of claim 10, wherein a compressed gas stream is fed into a cooling water system from at least about 1,900 psia to produce a cooled gas stream.

12. The system of claim 10, wherein a cooling water system uses water or a glycol/water mixture to cool a compressed gas stream to reduce moisture content.

13. The system of claim 10, comprising a vapor/liquid separator to condense and remove liquids from a compressed gas stream to produce a flash stream that is fed into a raw gas stream upstream of a suction scrubber.

14. The system of claim 10, wherein a gas treatment system comprises a dehydration section, a scrubber section, and a cryogenic expander section.

15. The system of claim 10, comprising a dehydration section configured to remove liquids from a cooled gas stream to form a waste water stream, wherein a waste water stream is fed into a raw gas stream upstream of a suction scrubber.

16. The system of claim 10, comprising an expansion device configured to remove condensed liquids from a cooled gas stream to form a cold vapor stream and a liquid stream, wherein the liquid stream is fed into a raw gas stream upstream of a suction scrubber.

17. The system of claim 10, comprising a regeneration gas separator to separate a portion of a cold vapor stream to produce a regeneration gas stream and a regeneration liquids stream, wherein the regeneration liquids stream is fed into a raw gas stream upstream of a suction scrubber.

18. The system of claim 10, comprising a compressor to compress a fuel gas before heating.

19. The system of claim 10, wherein a waste stream comprises contaminants, water, or in any combination thereof, wherein a pump increases a pressure of the waste stream for injection into a raw gas stream upstream of a suction scrubber.

20. The system of claim 10, wherein a heat exchanger heats a waste stream and a regeneration gas stream before entering a suction scrubber.

21. The system of claim 10, comprising a cooling water loop to heat a fuel gas, a waste stream, and a regeneration gas stream after heating in a heat exchanger.

22. A method for producing a fuel gas from a compressed natural gas, comprising:

flowing a raw natural gas through a suction scrubber to form a natural gas feed;

compressing the natural feed gas to form a compressed natural gas;

cooling the compressed natural gas in a cooler to produce a cooled natural gas;

feeding the cooled natural gas into a gas treatment system, comprising a low-temperature separator, to produce a natural gas stream and a waste stream;

heating the natural gas stream in a heat exchanger to form a superheated, sweetened natural gas;

combusting the superheated, sweetened natural gas in a turbine generator for use as an energy source; and

mixing the waste stream into the raw natural gas located upstream of the suction scrubber.

23. The method of claim 22, wherein a portion of cooled natural gas directed into a gas treatment system includes less than about 15%, about 10%, about 5%, or less of the total amount of the compressed natural gas.

24. The method of claim 22, comprising removing condensed liquids from a cooled natural gas stream to form a flash stream, wherein the flash stream is fed into an upstream compression scrubber.

25. The method of claim 22, comprising dehydrating a cooled natural stream, within a gas treatment system, to produce a cold natural gas stream and a waste water stream, wherein the waste water stream is fed into a raw gas stream upstream of a suction scrubber.

26. The method of claim 22, comprising removing condensed liquids from a cooled natural gas stream in an expansion device, within a gas treatment system, to produce a cold vapor natural gas and a liquid stream, wherein the liquid stream is fed into a raw gas stream upstream of a suction scrubber.

27. The method of claim 22, comprising feeding a portion of a cold vapor natural gas into a regeneration gas separator to generate a regeneration gas stream and a regeneration liquids stream, wherein the regeneration liquids stream is fed into the raw gas stream upstream of the suction scrubber.

28. The method of claim 22, comprising feeding a natural gas stream into a compressor before heating and wherein a waste stream is pumped into a raw gas stream upstream of a suction scrubber.

29. The method of claim 22, comprising heating a waste stream and a regeneration gas stream in a heat exchanger before flowing the waste stream and the regeneration gas into a suction scrubber.

30. The method of claim 22, comprising heating a natural gas stream, a reject stream, and a regeneration gas stream using a cooling water loop.

31. The method of claim 22, wherein a portion of a superheated, sweetened natural gas directed into a turbine generator may include less than about 15%, about 10%, about 5%, or less of the total amount of superheated, sweetened natural gas that is generated.

32. The method of claim 22, wherein about 15%, about 10%, about 5%, or less of the compressed gas stream is directed into the gas treatment system.

33. The method of claim 24, wherein about 15%, about 10%, about 5%, or less of the compressed gas stream is directed into the gas treatment system.