Patent US3984469A successfully refreshed from Google Patents.
US3984469A
Expired / Lapsed
US
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Process for the production of urea
Assignee: SnamProgetti SpA
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Filing: 1974-06-06
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Granted: 1976-10-05
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Expires: 1994-06-06
Abstract
Abstract A process for producing urea from CO 2 and NH 3 in which the CO 2 and NH 3 are reacted in a reactor, the reaction product is passed into a first stage decomposer maintained at the same pressure as the reactor, the reaction product is contacted in the first stage decomposer with NH 3 to form a urea solution substantially free of CO 2 , said urea solution substantially free of CO 2 is passed from the first stage decomposer to a second stage decomposer also maintained at the same pressure as the reactor and is contacted in said second stage decomposer with a stream of inert gas and an aqueous solution of substantially pure urea is withdrawn from the second reactor.
Inventors
- 👤 Mario Guadalupi
- 👤 Umberto Zardi
- 👤 Vincenzo Lagana
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:02
CPC Classifications
C; C07; C07C; C07C273/00; C07C273/02; C07C273/04; Y; Y02; Y02P; Y02P20/00; Y02P20/141
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
138 words
A process for the production of urea from CO 2 and NH 3 which comprises reacting CO 2 and NH 3 in a reactor to form a liquid reaction product containing urea and ammonium carbamate, passing said reaction product to a first stage decomposer maintained at substantially the same pressure as the said reactor wherein said reaction product is heated and contacted with gaseous NH 3 to form a urea solution substantially free of CO 2 , passing said urea solution substantially free of CO 2 to a second stage decomposer having a pressure substantially equal to said reactor wherein said urea solution is heated and contacted with a stream consisting essentially of an inert gas so as to strip any remaining NH 3 and withdrawing from said second stage decomposer an aqueous solution of substantially pure urea.
Claim 2
Dependent Claim
138 words
A process for the production of urea from CO 2 and NH 3 which comprises reacting CO 2 and NH 3 in a reactor to form a liquid reaction product containing urea and ammonium carbamate, passing said reaction product to a first stage decomposer maintained at substantially the same pressure as the said reactor wherein said reaction product is heated and contacted with gaseous NH 3 to form a urea solution substantially free of CO 2 , passing said urea solution substantially free of CO 2 to a second stage decomposer having a pressure substantially equal to said reactor wherein said urea solution is heated and contacted with a stream consisting essentially of an inert gas so as to strip any remaining NH 3 and withdrawing from said second stage decomposer an aqueous solution of substantially pure urea.
Claim 3
Dependent Claim
61 words
A process for the production of urea as recited in claim 1 wherein a mixture of said inert gas, and NH 3 are withdrawn from the upper end of said second stage decomposer and said mixture is passed to a condenser where said inert gas is separated from said NH 3 and said separated NH 3 is passed to said reactor.
Claim 4
Dependent Claim
17 words
A process as described in claim 1 wherein the reactor pressure range from 50 to 300 atmospheres.
Claim 5
Dependent Claim
17 words
A process as recited in claim 2 wherein the reactor pressure range from 50 to 300 atmospheres.
References Cited (Backward Citations)
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US3281464A
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US3514484A
Cited
GB1124868A
Cited
US3607938A
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US3647872A
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US3674847A
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US3816528A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-10-05 | 1980-04-05 | 1980-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-05 | 1984-04-05 | 1984-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-05 | 1988-04-05 | 1988-10-05 | $7700.00 | Window Closed / Lapsed |