Recovery of Carbon Monoxide and Hydrogen From Hydrocarbon Streams

• US 20090193846A1
• Filed: 07/28/2005
• Published: 08/06/2009
• Est. Priority Date: 07/28/2005
• Status: Abandoned Application

• Current Assignee: Ineos USA LLC (Ineos AG)
• Original Assignee: Ineos USA LLC (Ineos AG)
• Inventors: Reyneke, Rian, Eng, Wayne W.Y., Parker, Graeme, Foral, Michael J.
• Application Number:
  US11/922,951
• Publication Number:
  US 20090193846A1
• Time in Patent Office: Days
• US Class Current: 62/620
• CPC Class Codes: C01B 2203/044 Selective oxidation of carbon monoxide
• 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 32/40 Carbon monoxide
• CPC Class Codes: C07C 11/02 Alkenes
• CPC Class Codes: C07C 7/04 by distillation
• CPC Class Codes: C07C 7/09 by fractional condensation
• CPC Class Codes: F25J 2200/70 Refluxing the column with a condensed part of the feed stream, i.e. fractionator top is stripped or self-rectified
• CPC Class Codes: F25J 2200/74 Refluxing the column with at least a part of the partially condensed overhead gas
• CPC Class Codes: F25J 2200/76 Refluxing the column with condensed overhead gas being cycled in a quasi-closed loop refrigeration cycle
• CPC Class Codes: F25J 2200/78 Refluxing the column with a liquid stream originating from an upstream or downstream fractionator column
• CPC Class Codes: F25J 2200/80 using integrated mass and heat exchange, i.e. non-adiabatic rectification in a reflux exchanger or dephlegmator
• CPC Class Codes: F25J 2205/02 using simple phase separation in a vessel or drum
• CPC Class Codes: F25J 2205/04 in the feed line, i.e. upstream of the fractionation step
• CPC Class Codes: F25J 2205/30 using a washing, e.g. "scrubbing" or bubble column for purification purposes
• CPC Class Codes: F25J 2210/12 Refinery or petrochemical off-gas
• CPC Class Codes: F25J 2245/02 Recycle of a stream in general, e.g. a by-pass stream
• CPC Class Codes: F25J 2270/04 Internal refrigeration with work-producing gas expansion loop
• CPC Class Codes: F25J 2270/08 Internal refrigeration by flash gas recovery loop
• CPC Class Codes: F25J 2270/24 : Quasi-closed internal or closed external carbon monoxide refrigeration cycle
• CPC Class Codes: F25J 2270/90 : External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration
• 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 3/0223 : H2/CO mixtures, i.e. synthesis gas; Water gas or shifted synthesis gas production of carbon monoxide containing gas in general C01B32/40, C10J, C10K; production of hydrogen containing gas C01B3/00
• 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
• CPC Class Codes: F25J 3/0261 : separation of carbon monoxide production of carbon monoxide containing gas in general C01B32/40, C10J, C10K
• CPC Class Codes: Y02C 20/40 : of CO2

Abstract

A process is described for the recovery of CO and optionally hydrogen from a stream containing CO, H2, methane, and hydrocarbons heavier than methane. The process is characterized by a two-stage removal (3, 6) of C2+ hydrocarbons from the feed. In a first step the feed gas (1) is separated (3) into a first C2+ depleted stream (5) and a first C2+ enriched stream (4). The first C2-enriched stream (4) is rectified (6) to produce a second C2+ depleted stream. The first and second C2+ depleted streams (5, 9) are fed to a cryogenic system (10) fro recovery of CO (12) and optionally hydrogen (11).

Claims

1-15. -15. (canceled)

16. A process for the separation of carbon monoxide and optionally hydrogen from a process stream comprising carbon monoxide, hydrogen, methane and 2-30 mole % hydrocarbons with 2 or more carbons atoms, said process comprising:

a) passing the process stream to a first separation step to separate the process stream into a first intermediate stream comprising at least 90% by mole of the hydrocarbons with 2 or more carbons atoms that were present in the process stream and a reduced quantity of carbon monoxide, hydrogen and methane, and a second intermediate stream comprising carbon monoxide, hydrogen and methane and a reduced quantity of hydrocarbons with 2 or more carbons atoms,

b) passing the first intermediate stream to a second separation step to separate the first intermediate stream into a product stream comprising at least 90% by mole of the hydrocarbons with 2 or more carbons atoms that were present in the first intermediate stream and less than 1% of the carbon monoxide, hydrogen and methane that was present in the first intermediate stream, and a third intermediate stream comprising carbon monoxide, hydrogen and methane, and

c) treating both the second and third intermediate streams in a cryogenic separation system to separate the carbon monoxide, and optionally the hydrogen, therein.

17. A process as claimed in claim 16, wherein the process produces a purified carbon monoxide stream, a purified hydrogen stream, a purified methane stream, and a product stream comprising hydrocarbons with 2 or more carbon atoms.

18. A process as claimed in claim 16, wherein the first separation step comprises partial condensation of the process stream, followed by vapor/liquid separation in a flash drum or in a rectification column.

19. A process as claimed in claim 16, wherein the first separation step comprises a combined rectification and chilling process, such as a dephlegmator, a distillation column with side condensers or an advanced heat integrated rectifier system.

20. A process as claimed in claim 16, wherein the first separation step produces a second intermediate stream comprising less than 1.0%, by mole, of hydrocarbons with 2 or more carbons atoms.

21. A process as claimed in claim 16, wherein the second separation step comprises vapor/liquid separation in a flash drum or in a distillation column.

22. A process as claimed in claim 16, wherein the second separation step comprises a combined rectification and chilling process, such as a dephlegmator, a distillation column with side condensers or an advanced heat integrated rectifier system.

23. A process as claimed in claim 16, wherein the second separation step comprises a distillation column that contains both a rectification section and a stripping section.

24. A process as claimed in claim 16, wherein the second separation step produces a third intermediate stream comprising less than 1.0%, by mole, of hydrocarbons with 2 or more carbons atoms.

25. A process as claimed in claim 16, wherein in step (c):

(i) At least a portion of the second intermediate stream is passed to a methane wash tower wherein said portion is contacted with methane to give an overheads stream comprising predominantly hydrogen and a bottoms stream comprising carbon monoxide and methane, and

(ii) the bottoms stream is then passed, with the third intermediate stream, to a carbon monoxide recovery process comprising a hydrogen stripper column and a carbon monoxide purification column.

26. A process as claimed in claim 25 wherein both the bottoms stream and the third intermediate stream are passed to the hydrogen stripper column, with the third intermediate stream being used as a reflux liquid stream and a bottoms stream from the hydrogen stripper column, rich in carbon monoxide and methane, is passed to the carbon monoxide purification column where the carbon monoxide and methane are separated as respective carbon monoxide-rich and methane-rich product streams.

27. A process as claimed in claim 16, wherein in step (c) the second and third intermediate streams are treated separately until they enter a common carbon monoxide purification column.

28. A process as claimed in claim 27, wherein:

(i) the second intermediate stream is passed to a rectification column where it is contacted with a reflux liquid stream comprising carbon monoxide which has itself been separated from the overhead stream from the rectification column to produce a first hydrogen-rich stream and a bottoms stream comprising predominantly methane and carbon monoxide, with some hydrogen, (ii) passing the bottoms stream from the rectification column to a hydrogen stripper column to recover a second hydrogen-rich stream and a first stream rich in carbon monoxide and methane, (iii) treating the third intermediate stream to remove hydrogen therein to produce a third hydrogen-rich stream and a second stream rich in carbon monoxide and methane, and (iv) passing the first and second streams rich in carbon monoxide and methane to a carbon monoxide purification column wherein the carbon monoxide and methane are separated as respective carbon monoxide-rich and methane-rich product streams.

29. A process as claimed in claim 16 wherein the process stream comprising carbon monoxide, hydrogen, methane and hydrocarbons with 2 or more carbons atoms is derived from the product stream of an autothermal cracking process for the production of olefins.

30. A process as claimed in claim 29 which process comprises:

(a) autothermally cracking a hydrocarbon-containing feedstock and an oxygen-containing gas in an autothermal cracking reactor over a supported catalyst capable of supporting combustion beyond the fuel rich limit of flammability to produce a product stream comprising olefins, unreacted hydrocarbons, hydrogen, carbon monoxide, methane, and small amounts of acetylenes, aromatics and carbon dioxide,

(b) quenching the reaction products in the product stream with water as they emerge from the autothermal cracking reactor,

(c) removing carbon dioxide from the product stream,

(d) passing all or a portion of this product stream to a first separation step to separate the product stream into a first intermediate stream comprising hydrocarbons with 2 or more carbons atoms and a reduced quantity of carbon monoxide, hydrogen and methane, and a second intermediate stream comprising carbon monoxide, hydrogen and methane and a reduced quantity of hydrocarbons with 2 or more carbons atoms,

(e) passing the first intermediate stream to a second separation step to separate the first intermediate stream into a product stream comprising hydrocarbons with 2 or more carbons atoms and a third intermediate stream comprising carbon monoxide, hydrogen and methane, and

(f) treating both the second and third intermediate streams in a cryogenic separation system to separate the carbon monoxide, and optionally the hydrogen, therein.