US4549890A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process and plant for removing methane and argon from crude ammonia synthesis gas
Assignee: Air Products and Chemicals Inc
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Filing: 1983-12-01
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Granted: 1985-10-29
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Expires: 2003-12-01
Abstract
Abstract A process for removing methane and argon from crude ammonia synthesis gas, which method comprises the steps of: (a) cooling said crude ammonia synthesis gas in a heat exchanger; (b) distilling the cooled crude ammonia synthesis gas to provide purified ammonia synthesis gas and a liquid fraction containing methane, argon and nitrogen; (c) expanding said liquid fraction containing methane, argon and nitrogen; (d) introducing at least part of the liquid from step (c) into indirect heat exchange with vapor from the top of said distillation column to condense part of said vapor and provide reflux for said distillation column while simultaneously separating said liquid into a liquid stream rich in methane, and a gaseous stream rich in nitrogen; (e) warming said gaseous stream from step (d); (f) compressing at least part of the warmed gaseous stream from step (e); (g) cooling at least part of the compressed gaseous stream from step (f); (h) expanding at least part of the cooled gaseous stream from step (g); and (i) passing the expanded gaseous stream from step (h) through said heat exchanger. There is also provided a plant in which the said process can be carried out.
Inventors
- 👤 Bernard R. Bligh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:52
CPC Classifications
F; F25; F25J; F25J3/00; F25J3/02; F25J3/0204; F25J3/0219; C; C01; C01B; C01B3/00; C01B3/02; C01B3/025; F25J3/0228; F25J3/0233; F25J3/0252; F25J3/0257; F25J3/0276; F25J2200/00; F25J2200/02; F25J2200/50; F25J2200/74; F25J2205/00; F25J2205/02; F25J2210/00; F25J2210/20; F25J2270/00; F25J2270/02; F25J2270/04; F25J2270/42; F25J2270/88; Y; Y10; Y10S; Y10S62/00; Y10S62/923; Y10S62/924; Y10S62/931; Y10S62/934
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
191 words
A process for removing methane and argon from crude ammonia synthesis gas, which method comprises the steps of: (a) providing a crude ammonia synthesis gas having 26-31 volume percent nitrogen; (b) cooling said crude ammonia synthesis gas in a heat exchanger; (c) distilling the cooled crude ammonia synthesis gas to provide purified ammonia synthesis gas and a liquid fraction containing methane, argon and nitrogen; (d) expanding said liquid fraction containing methane, argon and nitrogen; (e) introducing at least part of the liquid from step (d) into indirect heat exchange with vapor from the top of said distillation column to condense part of said vapor and provide reflux for said distillation column whilst simultaneously separating said liquid into a liquid stream rich in methane, and a gaseous stream rich in nitrogen; (f) warming said gaseous stream from step (e); (g) compressing at least part of the warmed gaseous stream from step (f); (h) cooling at least part of the compressed gaseous stream from step (g); (i) expanding at least part of the cooled gaseous stream from step (h); and (j) passing the expanded gaseous stream from step (i) through said heat exchanger.
Claim 2
Dependent Claim
191 words
A process for removing methane and argon from crude ammonia synthesis gas, which method comprises the steps of: (a) providing a crude ammonia synthesis gas having 26-31 volume percent nitrogen; (b) cooling said crude ammonia synthesis gas in a heat exchanger; (c) distilling the cooled crude ammonia synthesis gas to provide purified ammonia synthesis gas and a liquid fraction containing methane, argon and nitrogen; (d) expanding said liquid fraction containing methane, argon and nitrogen; (e) introducing at least part of the liquid from step (d) into indirect heat exchange with vapor from the top of said distillation column to condense part of said vapor and provide reflux for said distillation column whilst simultaneously separating said liquid into a liquid stream rich in methane, and a gaseous stream rich in nitrogen; (f) warming said gaseous stream from step (e); (g) compressing at least part of the warmed gaseous stream from step (f); (h) cooling at least part of the compressed gaseous stream from step (g); (i) expanding at least part of the cooled gaseous stream from step (h); and (j) passing the expanded gaseous stream from step (i) through said heat exchanger.
Claim 3
Dependent Claim
24 words
A process according to claim 1 wherein steps (f) and (h) are carried out in the same heat exchanger as steps (b) and (j).
Claim 4
Dependent Claim
25 words
A process according to claim 2, wherein part of the warmed gas from step (f) is compressed and introduced into said crude ammonia synthesis gas.
Claim 5
Dependent Claim
25 words
A process according to claim 1, wherein part of the warmed gas from step (f) is compressed and introduced into said crude ammonia synthesis gas.
Claim 6
Dependent Claim
21 words
A process according to claim 1, wherein the cooled crude ammonia synthesis gas enters step (c) wholly in the gaseous phase.
Claim 7
Dependent Claim
27 words
A process according to claim 5, wherein said cooled crude ammonia synthesis gas enters step (c) at or not more than 10° C. above its dew point.
Claim 8
Dependent Claim
27 words
A process according to claim 5, wherein said cooled crude ammonia synthesis gas enters step (c) at or not more than 5° C. above its dew point.
Claim 9
Dependent Claim
32 words
A process according to claim 5 wherein part of the refrigeration required to achieve the distilling step (c) is provided by a condensed part of the cooled gaseous stream from step (h).
Claim 10
Dependent Claim
215 words
A plant comprising means designed for removing methane and argon from crude ammonia synthesis gas having 26-31 volume percent nitrogen, which plant including: (a) a heat exchanger for cooling crude ammonia synthesis gas; (b) a distillation column for distilling the cooled crude ammonia synthesis gas to provide, in use, purified ammonia synthesis gas and a liquid fraction containing methane, argon and nitrogen; (c) means for expanding said liquid fraction containing methane, argon and nitrogen; (d) means for, in use, conveying at least part of the liquid from step (c) into indirect heat exchange with vapour from the top of said distillation column to condense part of said vapour and provide reflux for said distillation column whilst simultaneously separating said liquid into a liquid stream rich in methane, and a gaseous stream rich in nitrogen; (e) means to warm, in use, at least part of the gaseous stream from step (d); (f) a compressor to compress, in use, the warmed gaseous stream from means (e); (g) means to cool, in use, at least part of the compressed gaseous stream from said compressor; (h) an expander for expanding, in use, at least part of the cooled compressed gaseous stream from means (g); and (i) a pipe for carrying expanded gas from said expander to said heat exchanger.
Claim 11
Dependent Claim
215 words
A plant comprising means designed for removing methane and argon from crude ammonia synthesis gas having 26-31 volume percent nitrogen, which plant including: (a) a heat exchanger for cooling crude ammonia synthesis gas; (b) a distillation column for distilling the cooled crude ammonia synthesis gas to provide, in use, purified ammonia synthesis gas and a liquid fraction containing methane, argon and nitrogen; (c) means for expanding said liquid fraction containing methane, argon and nitrogen; (d) means for, in use, conveying at least part of the liquid from step (c) into indirect heat exchange with vapour from the top of said distillation column to condense part of said vapour and provide reflux for said distillation column whilst simultaneously separating said liquid into a liquid stream rich in methane, and a gaseous stream rich in nitrogen; (e) means to warm, in use, at least part of the gaseous stream from step (d); (f) a compressor to compress, in use, the warmed gaseous stream from means (e); (g) means to cool, in use, at least part of the compressed gaseous stream from said compressor; (h) an expander for expanding, in use, at least part of the cooled compressed gaseous stream from means (g); and (i) a pipe for carrying expanded gas from said expander to said heat exchanger.
Claim 12
Dependent Claim
16 words
A plant as claimed in claim 9 wherein means (e) and (g) comprise said heat exchanger.
References Cited (Backward Citations)
US4270939A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-10-28 | 1989-04-29 | 1989-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-28 | 1993-04-29 | 1993-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-28 | 1997-04-29 | 1997-10-29 | $7700.00 | Window Closed / Lapsed |