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Patent US4190622A successfully refreshed from Google Patents.
US4190622A
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Process for prilling urea
Assignee: Standard Oil Co
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Filing: 1978-05-04
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Granted: 1980-02-26
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Expires: 1998-05-04
Abstract
Abstract Urea prills are obtained by contacting molten urea droplets with a co-current gas stream in a prill tower and cooling and collecting the prills thus formed in a fluidized bed having a second gas stream flowing countercurrent to the prills.
Inventors
- 👤 Norris J. Landis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:23
CPC Classifications
C; C05; C05C; C05C9/00; C05C9/005; B; B01; B01J; B01J2/00; B01J2/02; B01J2/04; B01J2/16; C05C1/00; C05C1/02; Y; Y10; Y10S; Y10S264/00; Y10S264/51
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
83 words
A process for prilling a material in a tower wherein droplets of molten material fall through a first zone and are contacted co-currently with a first gas stream and at least partially solidifying said material thereby forming a prill, and cooling and collecting said prills in a second zone comprising a fluid bed, said bed being maintained by a second gas stream flowing countercurrent to the first gas stream, wherein both first and second gas stream exit near the bottom of the tower.
Claim 2
Dependent Claim
83 words
A process for prilling a material in a tower wherein droplets of molten material fall through a first zone and are contacted co-currently with a first gas stream and at least partially solidifying said material thereby forming a prill, and cooling and collecting said prills in a second zone comprising a fluid bed, said bed being maintained by a second gas stream flowing countercurrent to the first gas stream, wherein both first and second gas stream exit near the bottom of the tower.
Claim 3
Dependent Claim
12 words
The process of claim 1 wherein the first gas stream is air.
Claim 4
Dependent Claim
12 words
The process of claim 1 wherein the second gas stream is air.
Claim 5
Dependent Claim
12 words
The process of claim 2 wherein the second gas stream is air.
Claim 6
Dependent Claim
10 words
The process of claim 4 wherein the material is urea.
Claim 7
Dependent Claim
11 words
The process of claim 4 wherein the material is ammonium nitrate.
Claim 8
Dependent Claim
19 words
The process of claim 4 wherein the co-current and countercurrent airstreams are combined prior to exiting the prill tower.
Claim 9
Dependent Claim
22 words
The process of claim 4 wherein the combined airstreams pass through a dust collection system wherein dust is removed from the air.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-02-25 | 1983-08-27 | 1984-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-02-25 | 1987-08-27 | 1988-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-02-25 | 1991-08-27 | 1992-02-26 | $7700.00 | Window Closed / Lapsed |