Hydrogen Recovery From A Mixture Of Hydrogen and Hydrocarbons At Low Pressure And Of Low Hydrogen Content

• US 20100037655A1
• Filed: 12/09/2008
• Published: 02/18/2010
• Est. Priority Date: 08/13/2008
• Status: Abandoned Application

• Current Assignee: Air Liquide Process & Construction, Inc. (L'Air Liquide SA)
• Original Assignee: Air Liquide Process & Construction, Inc. (L'Air Liquide SA)
• Inventors: Grover, Bhadra S.
• Application Number:
  US12/330,544
• Publication Number:
  US 20100037655A1
• Time in Patent Office: Days
• US Class Current: 62/623
• CPC Class Codes: B01D 2256/16 Hydrogen
• CPC Class Codes: B01D 2257/502 Carbon monoxide
• CPC Class Codes: B01D 2257/7022 Aliphatic hydrocarbons
• CPC Class Codes: B01D 53/002 by condensation
• CPC Class Codes: B01D 53/047 Pressure swing adsorption
• CPC Class Codes: C01B 2203/046 Purification by cryogenic separation
• CPC Class Codes: C01B 2203/048 the impurity being an organic compound
• CPC Class Codes: C01B 3/506 at low temperatures
• CPC Class Codes: C01B 3/56 by contacting with solids; Regeneration of used solids C01B3/508 takes precedence
• CPC Class Codes: F25J 2200/72 Refluxing the column with at least a part of the totally condensed overhead gas
• CPC Class Codes: F25J 2205/40 using hybrid system, i.e. combining cryogenic and non-cryogenic separation techniques
• CPC Class Codes: F25J 2205/60 using adsorption on solid adsorbents, e.g. by temperature-swing adsorption [TSA] at the hot or cold end
• CPC Class Codes: F25J 2210/04 Mixing or blending of fluids with the feed stream
• CPC Class Codes: F25J 2210/12 Refinery or petrochemical off-gas
• CPC Class Codes: F25J 2215/62 Ethane or ethylene
• CPC Class Codes: F25J 2245/02 Recycle of a stream in general, e.g. a by-pass stream
• CPC Class Codes: F25J 2270/02 Internal refrigeration with liquid vaporising loop
• CPC Class Codes: F25J 2270/04 Internal refrigeration with work-producing gas expansion loop
• CPC Class Codes: F25J 2270/12 External refrigeration with liquid vaporising loop
• CPC Class Codes: F25J 2270/42 Quasi-closed internal or closed external nitrogen refrigeration cycle
• CPC Class Codes: F25J 2270/60 : Closed external refrigeration cycle with single component refrigerant [SCR], e.g. C1-, C2- or C3-hydrocarbons
• CPC Class Codes: F25J 2270/66 : Closed external refrigeration cycle with multi component refrigerant [MCR], e.g. mixture of hydrocarbons
• CPC Class Codes: F25J 2290/42 : Modularity, pre-fabrication of modules, assembling and erection, horizontal layout, i.e. plot plan, and vertical arrangement of parts of the cryogenic unit, e.g. of the cold box
• CPC Class Codes: F25J 3/0219 : Refinery gas, cracking gas, coke oven gas, gaseous mixtures containing aliphatic unsaturated CnHm or gaseous mixtures of undefined nature
• CPC Class Codes: F25J 3/0233 : separation of CnHm with 1 carbon atom or more
• CPC Class Codes: F25J 3/0238 : separation of CnHm with 2 carbon atoms or more
• CPC Class Codes: F25J 3/0252 : separation of hydrogen production of hydrogen containing gas in general C01B3/00, e.g. separation of hydrogen or hydrogen containing gases form gaseous mixtures at low temperatures C01B3/506

Abstract

A method for recovering hydrogen from a gas stream is presented. This method includes introducing a feed gas stream comprising hydrogen and methane to a first cold box, thereby producing a first hydrogen-enriched stream, and a first methane-enriched stream; then introducing the first hydrogen-enriched stream to a first feed compressor, thereby producing a compressed first hydrogen-enriched stream. The method includes introducing the compressed first hydrogen-enriched stream to a second cold box, thereby producing a second hydrogen-enriched stream, and a second methane-enriched stream; then introducing the second hydrogen-enriched stream to a second feed compressor, thereby producing a compressed second hydrogen-enriched stream. The method includes introducing the compressed second hydrogen-enriched stream to a third cold box, thereby producing a third hydrogen-enriched stream, and a third methane-enriched stream. This method includes introducing the third hydrogen-enriched stream to a third feed compressor, thereby producing a compressed third hydrogen-enriched stream; then introducing the compressed third hydrogen-enriched stream to a PSA, thereby producing a high pressure, high purity hydrogen stream, and a tail gas stream. This method includes introducing a first part of the tail gas stream to a tail gas compressor, and recycling the compressed tail gas back to the feed gas stream; then combining the first methane-enriched stream, the second methane-enriched stream, the third methane-enriched stream, and a second part of the tail gas stream into a fuel stream. And this method includes introducing the fuel stream to a methane compressor.

Claims

1. A method for recovering hydrogen from a gas stream comprising:

a. introducing a feed gas stream comprising hydrogen and methane to a first cold box, thereby producing a first hydrogen enriched stream, and a first methane enriched stream;

b. introducing said first hydrogen enriched stream to a first feed compressor, thereby producing a compressed first hydrogen enriched stream;

c. introducing a said compressed first hydrogen enriched stream to a second cold box, thereby producing a second hydrogen enriched stream, and a second methane enriched stream;

d. introducing said second hydrogen enriched stream to a second feed compressor, thereby producing a compressed second hydrogen enriched stream;

e. introducing a said compressed second hydrogen enriched stream to a third cold box, thereby producing a third hydrogen enriched stream, and a third methane enriched stream;

f. introducing said third hydrogen enriched stream to a third feed compressor, thereby producing a compressed third hydrogen enriched stream;

g. introducing said compressed third hydrogen enriched stream to a PSA, thereby producing a high pressure, high purity hydrogen stream, and a tail gas stream;

h. introducing a first part of said tail gas stream to a tail gas compressor, and recycling said compressed tail gas back to said feed gas stream;

i. combining said first methane enriched stream, said second methane enriched stream, said third methane enriched stream, and a second part of said tail gas stream into a fuel stream; and

j. introducing said fuel stream to a methane compressor.

2. The method of claim 1, wherein said feed gas stream comprises less than 50% hydrogen.

3. The method of claim 1, wherein said feed gas stream comprises about 40% hydrogen.

4. The method of claim 1, wherein said compressed third hydrogen enriched stream has a pressure greater than 300 psig.

5. The method of claim 1, wherein said compressed third hydrogen enriched stream has a pressure of about 310 psig.

6. The method of claim 1, wherein said pressure of 300 psig is achieved in less than three compressor stages, and wherein said feed gas is enriched in less than three cold boxes.

7. The method of claim 1, wherein the pressure of said feed gas is between about 50 psig and about 80 psig.

8. The method of claim 1, wherein said feed stream is compressed before going to said first cold box.

9. The method of claim 1, wherein said third hydrogen enriched stream comprises between about 80% and about 95% hydrogen.

10. The method of claim 1, wherein at least one of said first cold box, second cold box and said third cold box is an auto-refrigeration type cold box.

11. The method of claim 10, wherein said auto-refrigeration type cold box utilizes expansion of at least one of said first methane enriched stream, said second methane enriched stream, and said third methane enriched stream.

12. The method of claim 1, wherein at least one of said first cold box, second cold box and said third cold box use an external refrigeration loop.

13. The method of claim 12, wherein said external refrigeration loop is of the type selected from the group consisting of methane loop, nitrogen loop, and mixed refrigerant loop.

14. The method of claim 1, wherein said first feed compressor, said second feed compressor, and said third feed compressor are discrete machines.

15. The method of claim 1, wherein at least two of said first feed compressor, said second feed compressor, and said third feed compressor are combined into a single machine.

16. The method of claim 11, wherein said methane rich streams are expanded to different pressure levels.

17. The method of claim 1, wherein said expanded methane rich streams are recompressed to fuel system pressure.

18. The method of claim 1, wherein said feed gas contains impurities such as carbon monoxide and/or ethylene.

19. The method of claim 18, wherein said feed gas contains 0.1-2% ethylene.

20. The method of claim 1, wherein said methane rich streams contain ethylene.

21. The method of claim 20, wherein said ethylene containing methane rich streams are processed for separation of ethylene from methane.

22. The method of claim 21, wherein said ethylene separation is done by fractionation in a staged column.

23. The method of claim 22, wherein the staged column is reboiled by at least one stream selected from the group consisting of the first compressed hydrogen enriched stream, the second compressed hydrogen enriched stream, the third compressed hydrogen enriched stream, and the feed gas stream.

24. The method of claim 21, wherein said staged column is refluxed by condensed overhead stream of the staged column.