US3933956A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for prilling urea
Assignee: MECS Inc
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Filing: 1974-06-18
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Granted: 1976-01-20
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Expires: 1994-06-18
Abstract
Abstract Urea is prilled by spraying urea droplets downwardly into a solidification zone where it is contacted with a substantially inert gas. Prills are directed into a collector by diverting their flow by directing a gas through a perforated, inverted cone or pyramid located at the bottom of and in communication with said zone.
Inventors
- 👤 Ivo Mavrovic
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:58
CPC Classifications
C; C05; C05C; C05C9/00; C05C9/005; B; B01; B01J; B01J2/00; B01J2/02; B01J2/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
145 words
In a process for prilling urea, comprising: a. spraying molten, substantially anhydrous urea downwardly as droplets in a prilling tower through a solidification zone therein generally toward the bottom of said tower; b. contacting said droplets with a substantially inert gas passed into said zone to cool and solidify said droplets as anhydrous prills; and c. collecting said prills at a centrally located bottom of said zone; the improvement comprising: d. passing said gas through a hollow, perforated, inverted frustum trough countercurrently to said downwardly falling prills and maintaining gas flow, gas velocity and the angle of said trough through which said gas is so passed as a fine dispersion, so as to divert said downwardly flowing prills from a substantially vertical path to an oblique path toward said bottom of said zone and to prevent substantially all of said prills from contacting said trough.
Claim 2
Dependent Claim
145 words
In a process for prilling urea, comprising: a. spraying molten, substantially anhydrous urea downwardly as droplets in a prilling tower through a solidification zone therein generally toward the bottom of said tower; b. contacting said droplets with a substantially inert gas passed into said zone to cool and solidify said droplets as anhydrous prills; and c. collecting said prills at a centrally located bottom of said zone; the improvement comprising: d. passing said gas through a hollow, perforated, inverted frustum trough countercurrently to said downwardly falling prills and maintaining gas flow, gas velocity and the angle of said trough through which said gas is so passed as a fine dispersion, so as to divert said downwardly flowing prills from a substantially vertical path to an oblique path toward said bottom of said zone and to prevent substantially all of said prills from contacting said trough.
Claim 3
Dependent Claim
11 words
The process of claim 1, wherein said inert gas is air.
Claim 4
Dependent Claim
159 words
In a process for producing substantially spherical fertilizer particles, comprising: a. spraying molten, substantially anhydrous fertilizer in finely divided particle form downwardly in a tower through a solidification zone generally toward the bottom of said tower; b. contacting said particles with a substantially inert gas passed into said zone to cool and solidify said particles; and c. collecting the resulting cooled and solidified particles at a centrally located bottom of said zone; the improvement comprising: d. passing said gas through a hollow, perforated, inverted frustum trough countercurrently to said downwardly falling cooled and solidified particles and maintaining gas flow, gas velocity and the angle of said trough through which said gas is so passed as a fine dispersion, so as to divert said downwardly flowing cooled and solidified particles from a substantially vertical path to an oblique path toward said bottom of said zone and to prevent substantially all of said cooled and solidified particles from contacting said trough.
Claim 5
Dependent Claim
159 words
In a process for producing substantially spherical fertilizer particles, comprising: a. spraying molten, substantially anhydrous fertilizer in finely divided particle form downwardly in a tower through a solidification zone generally toward the bottom of said tower; b. contacting said particles with a substantially inert gas passed into said zone to cool and solidify said particles; and c. collecting the resulting cooled and solidified particles at a centrally located bottom of said zone; the improvement comprising: d. passing said gas through a hollow, perforated, inverted frustum trough countercurrently to said downwardly falling cooled and solidified particles and maintaining gas flow, gas velocity and the angle of said trough through which said gas is so passed as a fine dispersion, so as to divert said downwardly flowing cooled and solidified particles from a substantially vertical path to an oblique path toward said bottom of said zone and to prevent substantially all of said cooled and solidified particles from contacting said trough.
Claim 6
Dependent Claim
11 words
The process of claim 3, wherein said inert gas is air.
References Cited (Backward Citations)
CA590557A
Cited
US3836611A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-01-19 | 1979-07-21 | 1980-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-19 | 1983-07-21 | 1984-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-19 | 1987-07-21 | 1988-01-20 | $7700.00 | Window Closed / Lapsed |