GB2087381A - Urea production - Google Patents
Urea production Download PDFInfo
- Publication number
- GB2087381A GB2087381A GB8124264A GB8124264A GB2087381A GB 2087381 A GB2087381 A GB 2087381A GB 8124264 A GB8124264 A GB 8124264A GB 8124264 A GB8124264 A GB 8124264A GB 2087381 A GB2087381 A GB 2087381A
- Authority
- GB
- United Kingdom
- Prior art keywords
- decomposition
- pressure
- ammonia
- urea
- stage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 title claims abstract description 40
- 239000004202 carbamide Substances 0.000 title claims abstract description 40
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 8
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 69
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 56
- 238000000354 decomposition reaction Methods 0.000 claims abstract description 44
- 229910002092 carbon dioxide Inorganic materials 0.000 claims abstract description 28
- 229910021529 ammonia Inorganic materials 0.000 claims abstract description 27
- 238000003786 synthesis reaction Methods 0.000 claims abstract description 26
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 25
- 238000000034 method Methods 0.000 claims abstract description 23
- 239000001569 carbon dioxide Substances 0.000 claims abstract description 21
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 14
- 239000007792 gaseous phase Substances 0.000 claims description 6
- 239000007789 gas Substances 0.000 claims description 4
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 claims 3
- 239000001099 ammonium carbonate Substances 0.000 claims 3
- 235000012501 ammonium carbonate Nutrition 0.000 claims 3
- BVCZEBOGSOYJJT-UHFFFAOYSA-N ammonium carbamate Chemical group [NH4+].NC([O-])=O BVCZEBOGSOYJJT-UHFFFAOYSA-N 0.000 abstract description 9
- KXDHJXZQYSOELW-UHFFFAOYSA-N carbonic acid monoamide Natural products NC(O)=O KXDHJXZQYSOELW-UHFFFAOYSA-N 0.000 abstract description 9
- 229910000069 nitrogen hydride Inorganic materials 0.000 abstract description 7
- KXDHJXZQYSOELW-UHFFFAOYSA-M Carbamate Chemical compound NC([O-])=O KXDHJXZQYSOELW-UHFFFAOYSA-M 0.000 description 13
- 239000007788 liquid Substances 0.000 description 10
- 239000012530 fluid Substances 0.000 description 4
- 238000011282 treatment Methods 0.000 description 4
- 238000005979 thermal decomposition reaction Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005086 pumping Methods 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- -1 Cho2 Chemical compound 0.000 description 1
- VZTDIZULWFCMLS-UHFFFAOYSA-N ammonium formate Chemical compound [NH4+].[O-]C=O VZTDIZULWFCMLS-UHFFFAOYSA-N 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 238000005469 granulation Methods 0.000 description 1
- 230000003179 granulation Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C273/00—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
- C07C273/02—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of urea, its salts, complexes or addition compounds
- C07C273/04—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of urea, its salts, complexes or addition compounds from carbon dioxide and ammonia
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/141—Feedstock
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Saccharide Compounds (AREA)
Abstract
A process for the production of urea from ammonia and carbon dioxide in an NH3:CO2 molar ratio of from 5:1 to 8:1 comprises the synthesis of a urea solution in a synthesis reactor and the decomposition of ammonium carbamate contained in the resulting urea solution in two stages in decomposers, the first stage using ammonia as the stripping agent and the second stage using carbon dioxide as the stripping agent. The synthesis and the first decomposition stage are carried out under a pressure equal or substantially equal to each other, which pressure is from 180 to 250 bars, whereas the second decomposition stage is carried out under a pressure of from 30 to 50 bars lower than the pressure used in the first decomposition stage.
Description
SPECIFICATION
Urea production
This invention relates to the production of urea.
Many processes for the production of urea are known. The main problem in such processes is the recovery of the ammonium carbamate which is contained in the effluent from the urea synthesis reactor. To solve this problem, various different recovery operations have been suggested.
One of these operations is the thermal decomposition of the effluent with simultaneous stripping of the decomposition products with gases fed from the outside, more particularly with ammonia or carbon dioxide. Another of these operations is the thermal decomposition of the effluent with simultaneous self-stripping of the decomposition products with ammonia or possibly carbon dioxide, which are evolved from the synthesis reactor effluent during heating thereof.
Thermal decomposition and simultaneous self-stripping with excess ammonia dissolved in the effluent is disclosed in British Patent Specification No. 1,184,004. The self-stipping step required the use of a vertical tube-bundle heat exchanging apparatus through which the effluent from the urea synthesis reactor is caused to flow in the form of a thin film along the inner wall of the tubes of the bundle. The heat for the decomposition is supplied externally of the tubes by a hot fluid or any heat-yielding fluid. An apparatus which is suitable for this purpose is disclosed in British Patent Specification No. 1,552,682.
Decomposition with self-stripping and also decomposition with stripping, each taken alone, are not capable of stripping the entire content of carbamate from the aqueous urea solution.
This is especially true when the decomposition and stripping are carried out under pressure which is equal to or close to the synthesis pressure. For this reason, further treatment of the urea solution leaving the self-stripping stage is usually carried out. British Patent Specification
No. 1,184,004 describes such treatments, which are intended to remove the residual carbamate.
It is clear that such additional treatments can be performed by using a stripping agent. Thus,
Italian Patent No . 875,128 (corresponding to British Patent Specification No. 1,272,873) describes a second stripping stage which is carried out under the same pressure as the first selfstripping stage and in which the stripping fluid used is a mixture of N2 and H2 intended for ammonia synthesis.
The use of carbon dioxide as a stripping agent in a first decomposition stage is disclosed in
British Patent Specification No. 952,764. The use of CO2 as a stripping agent in a second stage is disclosed in German Offenlegungsschrift No. 2,819,218. In process disclosed in the latter, decomposition of the carbamate in a first stage in the presence of ammonia, and in a second stage in the presence of carbon dioxide, is effected. The second stage also acts as a stripping stage relative to the arnmonia dissolved in the urea solution, and both stages are effected under the same pressure as used in the urea synthesis reactor.In theory, the procedure according to a
German Offenlegungsschrift No. 2,819,218 can be carried out under very high pressures since the two-stage decomposition with the two stripping agents should effeciently remove both the carbamate and the dissolved ammonia in spite of the high pressures. It has been noted, however, that under high pressures in the decomposition stage with carbon dioxide, severe corrosion occurs. This is caused both by the high temperatures used to decompose the residual carbamate and by carbon dioxide itself which is, as is well known, extremely corrosive even at conventional temperatures.In addition, the procedure according to German Offenlegungsschrift
No. 2,819,218, even though, in theory, it ought to permit the complete removal of both the ammonium carbamate and the ammonia, is not conducive, in actual practice, to such a result since the final solution leaving the second stage still contains high amounts of ammonia and carbon dioxide, both free and in combination, of the order of magnitude of from 20% to 28%.
The presence of this residual amount of carbamate and the ammonia has the consequence that it is necessary to decomposing the carbamate in at least two stages, one of which is effected under a pressure of 10 to 25 bars and the other of which is effected under a pressure of 1 to 5 bars inasmuch as the heat level of the water used for cooling would not bring about the condensation of ammonia and carbon dioxide, so that they should be recycled by pumping them out in liquid form.
Another conventional process is disclosed in U.S. Patent Specification No. 3,607,938, according to which the decomposition of ammonium carbamate is carried out in two stages, the first of which has ammonia as one of the stripping agents and is effected under the same pressure as the synthesis reaction, whereas the second stage has carbon dioxide as one of its stripping agents and is effected under a pressure which is lower than the synthesis pressure.
The corresion problem is solved by using, as the stripping agent in the second decomposer, CO2 together with a portion of decomposition products recycled to the stripper head, for the purpose of diluting the carbon dioxide in a large mass of ammonia, and above all, by using low synthesis and decomposition pressures, of the order of magnitude of 1 35 bars. The use of such comparatively low pressures obviously involves a lower urea yield, so that the process is not economically satisfactory.
It has now surprisingly been found that it is possible to decompose ammonium carbamate in the second stripping stage with carbon dioxide while avoiding the corrosion phenomena described above and dispensing with decompositing the residual carbamate in the low pressures stages, while concurrently carrying out the synthesis under high pressures, the consequential advantage being a high yeild.
According to the present invention, there is provided a process for the production of urea, which comprises synthesising a urea solution from ammonia and carbon dioxide, and decomposing the ammonium carbanate contained in the urea solution in two stages in the first of which ammonia is used as a self-stripping agent and in the second of which carbon dioxide is used as an external stripping agent, the synthesis and the first decomposition stage being carrier out at the same or substantially the same pressure, which pressure is from 180 to 250 bars, and the second decomposition stage being carried out at a pressure of from 30 to 50 bars less than the pressure at which the first decomposition stage is carried out.
According to a preferred embodiment, the process comprises (a) the synthesis of a urea solution under a pressure of from 1 80 to 250 bars from ammonia and carbon dioxide in an
NH3:CO2 molar ratio of from 5:1 to 8:1 in a synthesis zone; (b) the discharge of the solution thus obtained from the synthesis zone into a first ammonium carbamate zone wherein the excess ammonia which is present in the urea solution from the synthesis zone acts in counterflow with the solution as a self-stripping agent of the product of carbamate decomposition, the first decomposition zone operating under a pressure equal to or substantially equal to that of the synthesis zone; (c) the separation in the first decomposition zone of a urea solution containing an amount of carbamate of from 5 to 25% and of a gaseous phase comprising the products of decomposition of ammonium carbamate and an amount of ammonium in excess relative to the stoichiometric amount necessary to form ammonium carbamate and comprising from 50 to 90% of the total rate of flow of gases; and (d) the feeding of the urea solution from the first decomposition zone to a second decomposition zone operating under a pressure which is from 30 to 50 bars lower than that of the first decomposition zone, the stripping fluid in the second decomposition zone being carbon dioxide.
The temperature in the primary decomposition zone may be adjusted so as to respect the conditions reported above as to the amount of the residual carbamate in the urea solution and as to the amount of the excess of ammonia in the gaseous phase, the latter preferably being directly recycled, without being condensed, to the urea synthesis zone. The temperature in the first decomposition zone is preferably maintained in the range of from 180 to 215"C. The temperature in the second decomposition zone is preferably maintained in the range of from 160 to 210"C.
The decomposition products and the ammonia separated from the urea solution in the second decomposition zone may be condensed under a pressure which is substantially equal to that of the second decomposition zone, and the condesate may be recycled by pumping to the synthesis zone.
The process according to the present invention will now be described, by way of example, with reference to the accompanying drawing which schematically shows a plant in which the process can be carried out.
Liquid ammonia 1 is pumped by a pump 2 through coolers 3 and 4, and is then fed via a pipeline 5 to a urea synthesis reactor 6. The latter is fed, via a pipeline 7, with decomposition products and excess ammonia exiting a primary decomposer 8 to which is fed, via a pipeline 9, air so as to passivate the primary decomposer 8 as well as the reactor 6. The reactor 6 also receives, via a pipeline 10, condensates from a second decomposition stage.
The resulting urea solution, which contains unconverted ammonium carbamate and excess ammonia, is fed, via a pipeline 11, to the primary decomposer 8, from which is discharged, via a pipeline 12, a urea solution which contains the carbamate which has not been decomposed in the decomposer 8 and the excess ammonia which has not been removed in the decomposer 8.
This solution is allowed to expand in a valve 1 3 with a pressure drop of from 30 to 50 bars, and is fed to a secondary decomposer 14, wherein it is stripped with carbon dioxide fed along a pipeline 1 5 after having been compressed in a compressor 1 6.
The secondary decomposer 1 4 is also fed with a gaseous stream 1 7 which has been expanded in a valve 1 8 so as to reduce its pressure to the pressure pertaining in the secondary decomposer 24. This stream 1 7 originates from the head of the synthesis reactor 6, and is composed of NH3, Cho2, oxygen, nitrogen and other inert gases possibly present in the feed streams.
The vapour stripped in the secondary decomposer 14, as well as the C 2 used for stripping and inert materials, are discharged through a pipeline 1 9 and are then condensed in a condenser 20, the resulting liquid phase being separated from the resulting gaseous phase in a separator 22, and the two phases being passed along pipelines 10 and 21, respectively. The urea solution leaving the secondary decomposer 14 along pipeline 23 is then allowed to expand under'5iars to 1~bar, and is subjected to conventional distillation in a device 24 to obtain a solution which is passed along pipeline 32 and which is concentrated under vacuum in a device 25 to obtain a urea melt which is sent along pipeline 26 and then subjected to prilling or granulation.A condensate is also obtained from the device 25, this condensate being passed along pipeline 27 to a treatment section 35 to obtain sump liquor which is discharged along pipeline 33, and ammoniacal liquor which is recycled via a pipeline 34 to a condenser 28.
The ammonical vapour obtained at the head of the device 24 are also condensed in the condenser 28. The condensate is passed, via a pipeline 29, to a tank 30 from where it is recycled to the condenser 20 by means of a pump 31.
It is interesting to observe that, from an energy standpoint, the process described above with reference to the drawing is more advantageous than that of German Offenlegungsschrift No.
2,819, 218 because the omission of the stage under a pressure of 10 to 25 bars largely compensates for the expenditure in recompressing the carbamate which has been separated in the second stage to the pressure at which the synthesis is carried out.
An example of a process carried out in the plant shown in the drawing will now be given.
Example
For the production of 1,500 tons of urea per day, the plant shown in the drawing was used.
The most significant rates of flow in the various pipelines of the plant are given the the following
Table.
Table
Pipeline 1 5 15 11 12 23
Description NH3(Liquid) NH3(Liquid) CO2(Gas) Liquid Liquid Liquid
T( C) 15 120 160 190 200 180
P(Atmospheres) 10 200 150 200 200 150
NH3 (kg/h) 35417 (100%) - - 85877 (43.05%) 43603 (30%) 7543 (7%)
CO2 (kg/h) - - - - 48531 (100%) 16954 (8.5%) 10174 (7%) 9699 (9%)
Urea (kg/h) - - - - - - 62499 (31.33%) 62499 (43%) 62499 (58%)
H2O (kg/h) - - - - - - 34153 (17.12) 29070 (20%) 28016 (26%)
Total 35417 (100%) 35417 (100%) 45831 (100%) 199483 (100%) 145346 (100%) 107757 (100%)
Table (continued)
Pipeline 32 26 29 10 34
Description Liquid Urea-Melt* Liquid Liquid Liquid
T( C) 140 140 70 170 40
P(Atmospheres) 4.5 0.03 4.5 200 4.5
NH3 (kg/h) 1731 (2.0%) - - 7543 (28.4%) 43603 (39.66%) 1731 (32.58%)
CO2 (kg/h) 694 (0.8%) - - 9699 (36.6%) 56006 (50.95%) 694 (13.06%)
Urea (kg/h) 62499 (72.2%) 62499 (100%) - - - - -
H2O (kg/h) 21639 (25.0%) - - 9266 (35.0%) 10320 (9.39%) 2889 (54.36%)
Total 86563 (100%) 62499 (100%) 26508 (100%) 109929 (100%) 5314 (100%) *N:C=5:1; H:C=0.6:1; urea yield=0.73
Claims (9)
1. A process for the production of urea, which comprises synthesising a urea solution from ammonia and carbon dioxide, and decomposing the ammonium carbonate contained in the urea solution in two stages in the first of which ammonia is used as a self-stripping agent and in the second of which carbon dioxide is used as an external stripping agent, the synthesis and the first decomposition stage being carried out at the same or substantially the same pressure, which pressure is from 1 80 to 250 bars, and the second decomposition stage being carried out at a pressure of from 30 to 50 bars less than the pressure at which the first decomposition stage is carried out.
2. A process according to claim 1, wherein the urea solution is synthesised from ammonia and carbon dioxide in a molar ratio of from 5:1 to 8:1.
3. A process according to claim 1 or 2, wherein a urea solution containing from 5 to 25% of ammonium carbonate is obtained by the first decomposition stage.
4. A process according to any of claim 1 to 3, wherein a gaseous phase is obtained by the first decomposition stage, which gaseous phase contains a quantity of ammonia in excess of the stoichiometric amount required to form ammonium carbonate, which excess is form 50 to 90% over the total rate of flow of gas.
5. A process according to claim 4, wherein the gaseous phase obtained by the first decomposition stage is directly recycled to the urea synthesis, without being condensed.
6. A process according to any of claims 1 to 5, wherein the first decomposition stage is carried out at a temperature of from 180 to 215 C.
7. A process according to any of claims 1 to 6, wherein the second decomposition stage is carried out at a temperature of from 160 to 210 C.
8. A process according to claim 1, substantially as hereinbefore described with reference to, and as shown in, the accompanying drawing.
9. Urea produced by a process according to any of claims 1 to 8.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT24357/80A IT1141030B (en) | 1980-08-29 | 1980-08-29 | PROCEDURE FOR THE PRODUCTION OF UREA |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2087381A true GB2087381A (en) | 1982-05-26 |
| GB2087381B GB2087381B (en) | 1984-08-22 |
Family
ID=11213241
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8124264A Expired GB2087381B (en) | 1980-08-29 | 1981-08-07 | Urea production |
Country Status (35)
| Country | Link |
|---|---|
| JP (1) | JPS5772955A (en) |
| KR (1) | KR850000700B1 (en) |
| AR (1) | AR226915A1 (en) |
| AT (1) | AT377253B (en) |
| AU (1) | AU544041B2 (en) |
| BE (1) | BE890118A (en) |
| BR (1) | BR8105217A (en) |
| CA (1) | CA1182838A (en) |
| CS (1) | CS228529B2 (en) |
| DD (1) | DD201780A5 (en) |
| DE (1) | DE3133765C2 (en) |
| DK (1) | DK343381A (en) |
| EG (1) | EG15405A (en) |
| ES (1) | ES505481A0 (en) |
| FR (1) | FR2489323A1 (en) |
| GB (1) | GB2087381B (en) |
| IL (1) | IL63560A (en) |
| IN (1) | IN153584B (en) |
| IT (1) | IT1141030B (en) |
| LU (1) | LU83591A1 (en) |
| MW (1) | MW3181A1 (en) |
| MX (1) | MX152570A (en) |
| MY (1) | MY8500910A (en) |
| NL (1) | NL8104011A (en) |
| NO (1) | NO151199C (en) |
| PH (1) | PH18034A (en) |
| PL (1) | PL132177B1 (en) |
| PT (1) | PT73594B (en) |
| RO (1) | RO82682B (en) |
| SE (1) | SE447652B (en) |
| TR (1) | TR21103A (en) |
| YU (1) | YU194681A (en) |
| ZA (1) | ZA815329B (en) |
| ZM (1) | ZM7381A1 (en) |
| ZW (1) | ZW18981A1 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2514758A1 (en) * | 1981-10-16 | 1983-04-22 | Ammonia Casale Sa | PROCESS FOR PRODUCTION OF UREA |
| EP0157448A1 (en) * | 1984-03-16 | 1985-10-09 | Stamicarbon B.V. | Process for the preparation of urea |
| US4899813A (en) * | 1984-04-20 | 1990-02-13 | Snamprogetti S.P.A. | Process and apparatus for the synthesis of urea and material used in it |
| US5359140A (en) * | 1991-03-22 | 1994-10-25 | Snamprogetti S.P.A. | Urea production process of high energy efficiency |
| US8906187B2 (en) | 2008-06-25 | 2014-12-09 | Colgate-Palmolive Company | Method of making shoulder/nozzles with film barrier liners |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3364579D1 (en) * | 1982-06-03 | 1986-08-28 | Montedison Spa | Method for avoiding the corrosion of strippers in urea manufacturing plants |
| USD555828S1 (en) | 2005-08-04 | 2007-11-20 | Colgate-Palmolive Company | Dentifrice |
| ITMI20120013A1 (en) | 2012-01-09 | 2013-07-10 | Saipem Spa | PROCEDURE FOR THE SYNTHESIS OF UREA INCLUDING A STRIPPER FUND OF PASSIVATION |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL101446C (en) * | 1960-04-08 | |||
| US4053508A (en) * | 1960-09-05 | 1977-10-11 | Stamicarbon, N.V. | Process and installation for preparing urea from ammonia and carbon dioxide |
| CH498811A (en) * | 1967-05-22 | 1970-11-15 | Chemical Construction Corp | Process for the production of urea from ammonia and carbon dioxide |
| BE757274A (en) * | 1969-10-16 | 1971-03-16 | Snam Progetti | UREA PRODUCTION PROCESS |
| US3922222A (en) * | 1973-02-20 | 1975-11-25 | Cf Ind | Method for treatment of urea crystallizer condensate |
| IT1068268B (en) * | 1976-09-09 | 1985-03-21 | Snam Progetti | PROCEDURE FOR THE PRODUCTION OF UREA AND PURIFICATION OF WATERS |
| NO150512C (en) * | 1977-05-05 | 1984-10-31 | Montedison Spa | PROCEDURE FOR MANUFACTURING UREA. |
-
1980
- 1980-08-29 IT IT24357/80A patent/IT1141030B/en active
-
1981
- 1981-07-31 DK DK343381A patent/DK343381A/en not_active Application Discontinuation
- 1981-08-03 ZA ZA815329A patent/ZA815329B/en unknown
- 1981-08-05 ZW ZW189/81A patent/ZW18981A1/en unknown
- 1981-08-07 AU AU73904/81A patent/AU544041B2/en not_active Ceased
- 1981-08-07 GB GB8124264A patent/GB2087381B/en not_active Expired
- 1981-08-12 IL IL63560A patent/IL63560A/en unknown
- 1981-08-12 BR BR8105217A patent/BR8105217A/en unknown
- 1981-08-12 YU YU01946/81A patent/YU194681A/en unknown
- 1981-08-13 AT AT0354881A patent/AT377253B/en not_active IP Right Cessation
- 1981-08-18 MW MW31/81A patent/MW3181A1/en unknown
- 1981-08-20 ZM ZM73/81A patent/ZM7381A1/en unknown
- 1981-08-21 PH PH26083A patent/PH18034A/en unknown
- 1981-08-22 PL PL1981232761A patent/PL132177B1/en unknown
- 1981-08-24 NO NO812855A patent/NO151199C/en unknown
- 1981-08-25 TR TR21103A patent/TR21103A/en unknown
- 1981-08-25 FR FR8116244A patent/FR2489323A1/en active Granted
- 1981-08-26 CS CS816357A patent/CS228529B2/en unknown
- 1981-08-26 MX MX188902A patent/MX152570A/en unknown
- 1981-08-26 DD DD81232813A patent/DD201780A5/en unknown
- 1981-08-26 DE DE3133765A patent/DE3133765C2/en not_active Expired
- 1981-08-27 KR KR8103130A patent/KR850000700B1/en not_active Expired
- 1981-08-27 CA CA000384728A patent/CA1182838A/en not_active Expired
- 1981-08-27 BE BE0/205792A patent/BE890118A/en not_active IP Right Cessation
- 1981-08-27 LU LU83591A patent/LU83591A1/en unknown
- 1981-08-28 RO RO105188A patent/RO82682B/en unknown
- 1981-08-28 SE SE8105105A patent/SE447652B/en not_active IP Right Cessation
- 1981-08-28 JP JP56134360A patent/JPS5772955A/en active Pending
- 1981-08-28 ES ES505481A patent/ES505481A0/en active Granted
- 1981-08-28 PT PT73594A patent/PT73594B/en unknown
- 1981-08-28 AR AR286593A patent/AR226915A1/en active
- 1981-08-28 NL NL8104011A patent/NL8104011A/en not_active Application Discontinuation
- 1981-08-29 EG EG81491A patent/EG15405A/en active
- 1981-08-29 IN IN970/CAL/81A patent/IN153584B/en unknown
-
1985
- 1985-12-30 MY MY910/85A patent/MY8500910A/en unknown
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2514758A1 (en) * | 1981-10-16 | 1983-04-22 | Ammonia Casale Sa | PROCESS FOR PRODUCTION OF UREA |
| EP0157448A1 (en) * | 1984-03-16 | 1985-10-09 | Stamicarbon B.V. | Process for the preparation of urea |
| US4899813A (en) * | 1984-04-20 | 1990-02-13 | Snamprogetti S.P.A. | Process and apparatus for the synthesis of urea and material used in it |
| US5359140A (en) * | 1991-03-22 | 1994-10-25 | Snamprogetti S.P.A. | Urea production process of high energy efficiency |
| US8906187B2 (en) | 2008-06-25 | 2014-12-09 | Colgate-Palmolive Company | Method of making shoulder/nozzles with film barrier liners |
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| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19980807 |