Complete liquefaction methods and apparatus

• US 8,555,672 B2
• Filed: 10/22/2009
• Issued: 10/15/2013
• Est. Priority Date: 10/22/2009
• Status: Active Grant

• Current Assignee: Battelle Energy Alliance LLC (Battelle Memorial Institute)
• Original Assignee: Battelle Energy Alliance LLC (Battelle Memorial Institute)
• Inventors: Turner, Terry D., Wilding, Bruce M.
• Primary Examiner(s): Jones, Melvin
• Application Number:
  US12/603,948
• Publication Number:
  US 20110094262A1
• Time in Patent Office: 1,454 Days
• Field of Search: 62611-614, 62618-620
• US Class Current: 62/613
• CPC Class Codes: F25J 1/0022 Hydrocarbons, e.g. natural gas
• CPC Class Codes: F25J 1/0037 of a return stream
• CPC Class Codes: F25J 1/0045 by vaporising a liquid return stream
• CPC Class Codes: F25J 1/0202 in a quasi-closed internal refrigeration loop F25J1/0208, F25J1/0219, F25J1/0224 take precedence
• CPC Class Codes: F25J 2210/66 Landfill or fermentation off-gas, e.g. "Bio-gas"
• CPC Class Codes: F25J 2220/62 Separating low boiling components, e.g. He, H2, N2, Air
• CPC Class Codes: F25J 2230/30 Compression of the feed stream
• CPC Class Codes: F25J 2235/60 the fluid being (a mixture of) hydrocarbons
• CPC Class Codes: F25J 2245/90 the recycled stream being boil-off gas from storage

Abstract

A method and apparatus are described to provide complete gas utilization in the liquefaction operation from a source of gas without return of natural gas to the source thereof from the process and apparatus. The mass flow rate of gas input into the system and apparatus may be substantially equal to the mass flow rate of liquefied product output from the system, such as for storage or use.

Claims

1. A liquefaction plant configured to have an inlet connected to a source of gas, the liquefaction plant comprising:

a first mixer connected to the inlet;

a first splitter for splitting a gas stream from the first mixer into a cooling stream and a process stream;

a first compressor for compressing the cooling stream from the first splitter;

a heat exchanger for cooling the process stream into a liquid and a gas vapor;

a separation tank for separating the gas vapor from the liquid of the process stream;

a storage tank connected to a liquid outlet of the separation tank for storing the liquid;

an apparatus connecting a vapor outlet of the separation tank to the first mixer; and

an apparatus connecting a vapor outlet of the storage tank to the first mixer.

2. The liquefaction plant of claim 1, further comprising:

an expander coupled to the compressor for expanding the cooling stream;

an expansion valve for expanding the process stream after the heat exchanger; and

a second compressor for compressing at least a portion of a vapor from the storage tank and a portion of a vapor from the separation tank.

3. The liquefaction plant of claim 2, further comprising a third compressor for compressing the gas stream from the first mixer, prior to the first splitter.

4. The liquefaction plant of claim 3, further comprising an outlet of the second compressor connected to the first mixer.

5. The liquefaction plant of claim 1, further comprising a gas clean up unit for removing at least one of water, CO₂, and nitrogen from the gas.

6. The liquefaction plant of claim 1, further comprising an outlet of the separation tank connected to the storage tank through a pump.

7. The liquefaction plant of claim 1, further comprising a second mixer connected to the separation tank and to the storage tank.

8. The liquefaction plant of claim 7, further comprising a third mixer having an inlet thereof connected to the second mixer and an outlet thereof connected to the first mixer.

9. The liquefaction plant of claim 1, further comprising a second splitter connected to a liquid outlet of the separation tank for splitting the liquid from the separation tank into a process stream and a return stream.

10. The liquefaction plant of claim 9, further comprising a pump for pumping the process stream from the second splitter to the storage tank.

11. The liquefaction plant of claim 10, further comprising a pump for pumping the return stream from the second splitter.

12. The liquefaction plant of claim 9, further comprising a pump for pumping the liquid from the separation tank to the second splitter.

13. The liquefaction plant of claim 12, further comprising a valve for regulating the pressure of the process stream from the second splitter to the storage tank.

14. The liquefaction plant of claim 2, further comprising:

a third compressor connected to an outlet of the first mixer;

an ambient heat exchanger connected to the third compressor and the first splitter; and

an ambient heat exchanger connected to an outlet of the expander.

15. The liquefaction plant of claim 1, further comprising:

another compressor for receiving the gas stream from the first mixer, compressing the gas stream and delivering the gas stream to the first splitter.

16. A method of liquefying natural gas from a source of gas using a liquefaction plant having an inlet for gas, the method comprising:

flowing gas from the source of gas through the inlet and into a first mixer;

splitting a gas stream from the first mixer using a first splitter into a cooling stream and a process stream;

compressing the cooling stream using a compressor;

expanding the compressed cooling stream using an expander;

cooling the process stream with a heat exchanger;

separating vapor from liquid gas of the process stream in a separation chamber;

storing the liquid gas in a storage tank;

flowing vapor from the separation chamber and vapor from the storage tank into the first mixer to mix with gas from the source of gas;

forming gas from liquid gas in the separation vessel using the heat exchanger; and

flowing gas from the heat exchanger to the first mixer to mix with gas from the source of gas.

17. The method of claim 16, further comprising:

expanding the process stream after cooling thereof with the heat exchanger using an expansion valve.

18. The method of claim 16, further comprising:

pressurizing the liquid gas from the separation chamber to flow through the heat exchanger to the first mixer.

19. The method of claim 16, further comprising:

pumping the liquid gas from the separation chamber to the storage tank.

20. The method of claim 16, wherein flowing vapor from the separation chamber and vapor from the storage tank into the first mixer to mix with gas from the source of gas comprises flowing the vapor from the separation chamber and the vapor from the storage vessel using at least one compressor.

21. The method of claim 16, further comprising:

compressing the gas stream from the first mixer prior to splitting the gas stream with the first splitter.

22. A method of liquefying gas from a source of gas using a liquefaction plant having an inlet for gas, the method comprising:

flowing gas from the source of gas through the inlet and into a first mixer;

compressing a first stream of gas from the first mixer to produce a process stream;

splitting the process stream using a first splitter into a cooling stream and a process stream;

compressing the cooling stream using a compressor;

expanding the compressed cooling stream using an expander;

cooling the process stream in a heat exchanger;

expanding the process stream to further cool the process stream;

directing the process stream into a separation chamber to separate a liquid and a vapor of the process stream;

storing the liquid in a storage vessel;

flowing the vapor from the separation chamber and a vapor from the storage vessel into the first mixer to mix with gas from the source of gas;

vaporizing a portion of the liquid from the separation chamber using the heat exchanger; and

flowing gas from the heat exchanger to the first mixer to mix with gas from the source of gas.