IE83440B1 - Process for vaporizing a hydrazine hydrate solution - Google Patents
Process for vaporizing a hydrazine hydrate solutionInfo
- Publication number
- IE83440B1 IE83440B1 IE1990/4356A IE435690A IE83440B1 IE 83440 B1 IE83440 B1 IE 83440B1 IE 1990/4356 A IE1990/4356 A IE 1990/4356A IE 435690 A IE435690 A IE 435690A IE 83440 B1 IE83440 B1 IE 83440B1
- Authority
- IE
- Ireland
- Prior art keywords
- solution
- hydrazine hydrate
- column
- hydrazine
- vaporizing
- Prior art date
Links
- IKDUDTNKRLTJSI-UHFFFAOYSA-N hydrazine hydrate Chemical compound O.NN IKDUDTNKRLTJSI-UHFFFAOYSA-N 0.000 title claims description 62
- 238000000034 method Methods 0.000 title claims description 14
- OAKJQQAXSVQMHS-UHFFFAOYSA-N hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 claims description 21
- JUJWROOIHBZHMG-UHFFFAOYSA-N pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 claims description 9
- 150000007857 hydrazones Chemical class 0.000 claims description 8
- 239000007791 liquid phase Substances 0.000 claims description 6
- 238000006460 hydrolysis reaction Methods 0.000 claims description 5
- RTAQQCXQSZGOHL-UHFFFAOYSA-N titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 4
- 239000010936 titanium Substances 0.000 claims description 4
- 229910052719 titanium Inorganic materials 0.000 claims description 4
- 239000003795 chemical substances by application Substances 0.000 claims 1
- 229910000423 chromium oxide Inorganic materials 0.000 claims 1
- WGLPBDUCMAPZCE-UHFFFAOYSA-N trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 claims 1
- 239000000463 material Substances 0.000 description 7
- 238000009834 vaporization Methods 0.000 description 7
- 238000000354 decomposition reaction Methods 0.000 description 6
- 125000004432 carbon atoms Chemical group C* 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 229910000619 316 stainless steel Inorganic materials 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 3
- 238000004821 distillation Methods 0.000 description 3
- 150000002576 ketones Chemical class 0.000 description 3
- WQYVRQLZKVEZGA-UHFFFAOYSA-N Hypochlorite Chemical compound Cl[O-] WQYVRQLZKVEZGA-UHFFFAOYSA-N 0.000 description 2
- CSCPPACGZOOCGX-UHFFFAOYSA-N acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- UOUJSJZBMCDAEU-UHFFFAOYSA-N chromium(3+);oxygen(2-) Chemical class [O-2].[O-2].[O-2].[Cr+3].[Cr+3] UOUJSJZBMCDAEU-UHFFFAOYSA-N 0.000 description 2
- 230000000875 corresponding Effects 0.000 description 2
- 238000007872 degassing Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000010992 reflux Methods 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- 239000010963 304 stainless steel Substances 0.000 description 1
- PFLUPZGCTVGDLV-UHFFFAOYSA-N Acetone azine Chemical compound CC(C)=NN=C(C)C PFLUPZGCTVGDLV-UHFFFAOYSA-N 0.000 description 1
- 238000004131 Bayer process Methods 0.000 description 1
- 241001237731 Microtia elva Species 0.000 description 1
- 229910000589 SAE 304 stainless steel Inorganic materials 0.000 description 1
- 125000003545 alkoxy group Chemical group 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminum Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- WKBOTKDWSSQWDR-UHFFFAOYSA-N bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000002596 correlated Effects 0.000 description 1
- 125000000753 cycloalkyl group Chemical group 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 125000001153 fluoro group Chemical group F* 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 125000000654 isopropylidene group Chemical group C(C)(C)=* 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- -1 nitro, hydroxyl Chemical group 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000001590 oxidative Effects 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B21/00—Nitrogen; Compounds thereof
- C01B21/082—Compounds containing nitrogen and non-metals and optionally metals
- C01B21/16—Hydrazine; Salts thereof
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C243/00—Compounds containing chains of nitrogen atoms singly-bound to each other, e.g. hydrazines, triazanes
- C07C243/10—Hydrazines
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
- F28F21/08—Constructions of heat-exchange apparatus characterised by the selection of particular materials of metal
- F28F21/081—Heat exchange elements made from metals or metal alloys
- F28F21/082—Heat exchange elements made from metals or metal alloys from steel or ferrous alloys
-
- 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
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S203/00—Distillation: processes, separatory
- Y10S203/06—Reactor-distillation
Description
PROCESS FOR VAPORIZING A HYDRAZINE HYDRATE SOLUTION ELF ATOCHEM S.A.
The present invention relates to a process for vaporizing a hydrazine hydrate solution.
Industrial production of hydrazine hydrate is carried out by the Raschig, Bayer and Atochem processes.
In the Raschig process ammonia is oxidized with a hypochlorite to obtain a dilute solution of hydrazine hydrate which then must be concentrated by distillation.
The Bayer process is an alternative form of the Raschig process, which consists in shifting a chemical equilibrium by trapping, with the aid of acetone, the hydrazine formed in the form of azine (CH3)2C=N-N=C(CH3)2.
The azine is next isolated and then hydrolysed to hydrazine hydrate.
The Atochem process consists in oxidizing a mixture of ammonia and of a ketone using aqueous hydrogen peroxide in the presence of a catalyst to make the azine directly, which is then hydrolysed to hydrazine hydrate. The Atochem process is described in, for example. US-A-3,972,878, US-A- 3,972,876, US-A-3,948,902 and US-A-4,093,656.
The hydrolysis of an azine to hydrazine hydrate is described in US-A-4,724,133, Us-A—4,725,421 and GB-A- 1,164,460. It is carried out in a distillation column which is fed with water and with the azine; the ketone is recovered at the head and the hydrazine hydrate at the foot.
In the bottom of a hydrolysis column, as in the bottom of a column for concentrating hydrazine hydrate, there is a device for vaporizing the hydrazine hydrate.
We have found that some decomposition of the hydrazine hydrate is observed when using a reboiler with a therrnosiphon, a coil immersed in the bottom of the column or a tube bundle immersed in the bottom of the column and, as a general rule, a reboiler where the vaporization takes place in contact with the heating surface. We have found, according to the present invention, that if hydrazine hydrate is vaporized by decompression and not on contact with the surface for transferring heat energy, the decomposition can be substantially reduced.
According to the present invention there is provided a process for vaporizing a hydrazine hydrate solution which is at a pressure greater than atmospheric pressure and a temperature between 130° and 220°C, which consists in heating the solution substantially in the liquid phase and in then decompressing this solution.
The hydrazine hydrate solution may be a solution of water and hydrazine which can be anything from a highly water-diluted hydrazine (or the hydrate) to hydrazine hydrate. The hydrazine hydrate solution may be a solution which also contains an azine, a hydrazone or a ketone; this solution can be aqueous or anhydrous.
Azine and hydrazone denote, respectively, the products of formula: R1 R3 / c = N-N = c / \ R2 R4 and R5 C = N‘NH2 / R6 in which R1 and R5 are identical or different and denote hydrogen, a linear alkyl radical containing from 1 to 12 carbon atoms, a cycloalkyl or branched alkyl radical containing from 3 to 12 carbon atoms, or an aryl radical containing from 6 to 12 carbon atoms. The radicals R1 to R5 which are linked to the same carbon atom of the azine or of the hydrazone may themselves be linked and may together form a linear or branched alkylene radical containing from 3 to 12 carbon atoms.
All the above radicals R1 to R5 may also be substituted by, say, a chlorine, bromine or fluorine atom or a nitro, hydroxyl or alkoxy group or an ester functional group. The invention is particularly useful in the case of acetone azine: CH3(CH3)C=N-N=C(CH3)CH3 methyl ethyl ketazine C2H5(CH3)C=N-N=C(CH3)C3H5, and the corresponding hydrazones.
To heat this solution essentially in the liquid _ 5 - phase it suffices to place the liquid phase under pressure while it is being heated, that is to say that the hydrazine hydrate solution absorbs heat energy in the form of an increase in its temperature. Then this solution is decompressed and the above energy is restored in the form of a vaporization.
Part of the heat energy can be consumed by a hydrolysis reaction of an azine and/or of a hydrazone to a corresponding hydrazine or hydrazone.
Also, during the heating of the hydrazine hydrate solution a fraction, say up to 3 or 5 % by weight, of the solution which is heated and then decompressed, can be vaporized.
This invention will now be illustrated merely by way of example with reference to the accompanying Figure.
In this Figure, ; denotes a distillation column, ; a pump and ; a heat exchanger. The hydrazine hydrate solution at the foot of the column ; can be conveyed via pipe ;g by the pump g through the exchanger ; and then returns to the column via pipework ii. For simplicity, the withdrawal at the foot of the column ;, which may be, for example, at the delivery of g, has not been shown. The pump ; makes it possible to apply to the hydrazine hydrate solution a pressure which is higher than that at the bottom of the column ;, enabling it to travel through the exchanger ; and the pipe ll. This pressure makes it possible to keep the solution in essentially liquid phase in the exchanger ;. _ 6 _ The exchanger ; is fed at i; with steam or a heat—transfer fluid, which is removed at lg. A device for producing a pressure drop, such as a valve or a diaphragm, may be arranged at any point of the pipe ii. A person skilled in the art can easily choose to place or not to place a pressure drop device in the pipe i; as a function of the pressure drops generated by the exchanger 3 and the pipework ii. The relative pressure provided by the pump, that is to say the pressure difference between the pump delivery and the foot of the column may be of any magnitude, but is usually at least 0.5 bars and preferably from 1 to 10 bars.
If desired, the exchanger ;_and the pump g can be arranged well below the bottom level of the column 1. This generates an additional pressure on the hydrazine hydrate solution in the exchanger 1. Also, according to this embodiment, the pump g can be eliminated if the difference in level is sufficient to keep the solution in the liquid phase in the exchanger ;. This embodiment is of interest only if the column ; is at a sufficient height above ground.
The column ; may also be a simple storage vessel in which a reaction requiring vaporization can be carried out and which is provided with a feed and optionally with an overhead offtake with or without reflux, this column ; being optionally forming part of a plant. It may be, for example, a storage vessel in which an endothermic reaction is carried out.
The present invention is used for _ 7 _ vaporizing aqueous hydrazine hydrate solutions at temperatures above 130 to 220‘.’C.
The invention is thus particularly useful in the case of the boiler at the foot of a column for hydrolysis of azine or of hydrazone to hydrazine.
The present invention also relates to the use of particular materials for the surface of a device for vaporizing a hydrazine hydrate solution.
We have found that the decomposition of hydrazine varies according to the material forming the surface for the transfer of the vaporization energy, and that this is so (i) in the case of a vaporization consisting in heating the hydrazine hydrate solution essentially in liquid phase and then decompressing this solution and (ii) in the case of a conventional vaporization in a boiler with a thermosiphon, an immersed coil or, in general, any device in which the vaporization is produced in contact with the heating surface.
We have thus found that titanium, chromium oxides, aluminium, common steel, 304 stainless steel, 316 stainless steel, nickel and its alloys and zirconium can be classified in this order, titanium resulting in less decomposition than zirconium. 304 and 316 stainless steels are the usual designations of stainless steels according to the AISI (American Iron and Steel Institute) standard.
It is clear that the material of the device for vaporizing a hydrazine solution relates to the material in _ 3 _ contact with the hydrazine hydrate solution and not to the material in contact with the heating fluid. Chromium oxides are preferably employed as a coating for the metal surface.
A vessel of 300-1 capacity containing a solution of hydrazine hydrate is fitted with an external 5-m2 heat exchanger arranged vertically with return into the upper part of the vessel. It is also possible to arrange a pump capable of delivering 20 m3/hour with a gauge pressure head of 2 bars between the vessel and the exchanger and an exit diaphragm, to make it operate as a forced-circulation boiler. 250 kg/h of steam at 18 bars are condensed in the exchanger. The vessel is provided with a total reflux condenser to remove the energy supplied to the exchanger and with degassing in order to collect the nitrogen, hydrogen and ammonia originating from the decomposition of hydrazine, and thus to measure this decomposition.
The whole is built of steels and exchangers made of different materials have been tried out.
To test each material, the vessel is filled with 50 kg of hydrazine hydrate (N2H4.H2O) diluted in 250 kg of water, and 18-bar steam is then injected to run the exchanger as a boiler (250 kg/hour are condensed). The quantity of hydrazine remaining in the vessel is measured after one hour. This value is correlated by measuring the degassing. The pressure in the vessel is 9 bars gauge and the temperature 180°C. a) when operating as a thernosiphog If an exchanger made of 316 stainless steel is employed, 45 kg of hydrazine hydrate remain after one hour, 47 kg thereof remain in the case of steel and 48.5 kg in the case of titanium. b) when operating gith the pgp when using a 316 stainless steel exchanger 47.5 kg of hydrazine hydrate remain after one hour.
Claims (5)
1. Process for vaporizing a hydrazine hydrate solution which is at a pressure greater than atmospheric pressure and a temperature between 130° and 220°C, which consists in heating the solution substantially in the liquid phase and in then decompressing this solution.
2. Process according to Claim 1 in which the quantity vaporized during the heating is less than 5% of the quantity heated.
3. Process according to Claim 1 or 2 in which the solution is withdrawn from the bottom of a column, it is transferred by a pump into a heat exchanger, and this solution is then returned to the bottom of the column.
4. Process according to any one of Claims 1 to 3 which is employed for the reboiler of a column for hydrolysis of azine or of hydrazone to hydrazine.
5. Process according to any one of Claims 1 to 4 in which the heating surface is made of titanium or of chromium oxide. F. R. KELLY & co., AGENTS FOR THE APPLICANTS.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FRFRANCE04/12/19898915968 | |||
| FR8915968A FR2655336B1 (en) | 1989-12-04 | 1989-12-04 | PROCESS FOR VAPORIZING A HYDRAZINE HYDRATE SOLUTION. |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| IE83440B1 true IE83440B1 (en) | |
| IE904356A1 IE904356A1 (en) | 1991-06-05 |
Family
ID=9388103
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| IE435690A IE904356A1 (en) | 1989-12-04 | 1990-12-03 | Process for vaporizing a hydrazine hydrate solution |
Country Status (14)
| Country | Link |
|---|---|
| US (1) | US5393508A (en) |
| EP (2) | EP0952109B1 (en) |
| JP (1) | JP2607444B2 (en) |
| KR (1) | KR950003334B1 (en) |
| CN (1) | CN1043139C (en) |
| AT (2) | ATE201657T1 (en) |
| CA (1) | CA2031318C (en) |
| DE (2) | DE69033741T2 (en) |
| ES (2) | ES2165214T3 (en) |
| FI (1) | FI114546B (en) |
| FR (1) | FR2655336B1 (en) |
| IE (1) | IE904356A1 (en) |
| NO (1) | NO308840B1 (en) |
| PT (1) | PT96064B (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4329599C1 (en) * | 1993-09-02 | 1995-03-16 | Bayer Ag | Process for removing impurities from hydrazine hydrate |
| FR2778659B1 (en) * | 1998-05-14 | 2000-06-23 | Atochem Elf Sa | PROCESS FOR THE PREPARATION OF HYDRAZINE HYDRATE |
| FR2787437B1 (en) * | 1998-12-22 | 2001-02-09 | Atochem Elf Sa | PROCESS FOR THE MANUFACTURE OF HYDRAZINE BY HYDROLYSIS OF AN AZINE |
| CN100333814C (en) * | 2005-03-08 | 2007-08-29 | 湖南化工研究院 | Method for recovering and reutilizing industrial waste salt and apparatus thereof |
| CN100389892C (en) * | 2005-10-13 | 2008-05-28 | 宜宾天原股份有限公司 | Recovering treatment of hydrated hydrazine by-product saline-alkali by urea method |
| CN100389893C (en) * | 2005-10-13 | 2008-05-28 | 宜宾天原股份有限公司 | Recovering method of acetone and ammonia in hydrated hydrazine waste salt water by ketone azine method |
| CN105384655B (en) * | 2015-10-26 | 2017-08-25 | 宜宾海丰和锐有限公司 | A kind of method for removing impurity in ketazine process hydrazine hydrate hydrolysis system |
| CN108086960B (en) * | 2017-12-12 | 2020-04-28 | 大连理工大学 | Water flow erosion method natural gas hydrate exploitation experiment simulation method and device |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA584845A (en) * | 1959-10-13 | L. Womer Robert | Manufacture of hydrazine | |
| BE509407A (en) * | 1952-02-09 | |||
| US2799631A (en) * | 1952-10-07 | 1957-07-16 | Fairmount Chem | Process of recovering hydrazine |
| US2733195A (en) * | 1954-09-01 | 1956-01-31 | Process for concentrating aqueous | |
| GB761018A (en) * | 1954-10-11 | 1956-11-07 | Fairmount Chem | Process for recovering hydrazine |
| US3230158A (en) * | 1961-11-27 | 1966-01-18 | Phillips Petroleum Co | Method and apparatus for reboiling a heated system |
| DE1273503B (en) * | 1966-12-17 | 1968-07-25 | Bayer Ag | Process for the preparation of hydrazine from aqueous ketazine solutions |
| GB1207816A (en) * | 1966-12-17 | 1970-10-07 | Bayer Ag | Preparation of hydrazine hydrate from aqueous hydrazine sulfate |
| US4036936A (en) * | 1975-08-15 | 1977-07-19 | Otsuka Kagaku Yakuhin Kabushiki Kaisha | Process for preparing hydrazine hydrate |
| FR2323635A1 (en) * | 1975-09-10 | 1977-04-08 | Ugine Kuhlmann | PROCESS FOR PREPARING CONCENTRATED SOLUTIONS OF HYDRAZINE HYDRATE |
| FR2323634A1 (en) * | 1975-09-10 | 1977-04-08 | Ugine Kuhlmann | CONCENTRATED HYDRAZINE HYDRATE SOLUTIONS |
| JPS63295408A (en) * | 1987-05-28 | 1988-12-01 | Mitsubishi Gas Chem Co Inc | Method for purifying aqueous hydrazine hydrate solution |
-
1989
- 1989-12-04 FR FR8915968A patent/FR2655336B1/en not_active Expired - Fee Related
-
1990
- 1990-11-16 ES ES99111127T patent/ES2165214T3/en not_active Expired - Lifetime
- 1990-11-16 AT AT90403246T patent/ATE201657T1/en not_active IP Right Cessation
- 1990-11-16 DE DE69033741T patent/DE69033741T2/en not_active Expired - Fee Related
- 1990-11-16 ES ES90403246T patent/ES2157195T3/en not_active Expired - Lifetime
- 1990-11-16 AT AT99111127T patent/ATE206686T1/en not_active IP Right Cessation
- 1990-11-16 EP EP99111127A patent/EP0952109B1/en not_active Expired - Lifetime
- 1990-11-16 DE DE69033827T patent/DE69033827T2/en not_active Expired - Fee Related
- 1990-11-16 EP EP90403246A patent/EP0431998B1/en not_active Expired - Lifetime
- 1990-11-29 NO NO905169A patent/NO308840B1/en unknown
- 1990-12-01 CN CN90109520A patent/CN1043139C/en not_active Expired - Fee Related
- 1990-12-03 PT PT96064A patent/PT96064B/en not_active IP Right Cessation
- 1990-12-03 IE IE435690A patent/IE904356A1/en not_active IP Right Cessation
- 1990-12-03 KR KR1019900019783A patent/KR950003334B1/en not_active IP Right Cessation
- 1990-12-03 CA CA002031318A patent/CA2031318C/en not_active Expired - Fee Related
- 1990-12-03 FI FI905951A patent/FI114546B/en active IP Right Grant
- 1990-12-04 JP JP2404007A patent/JP2607444B2/en not_active Expired - Fee Related
-
1993
- 1993-09-10 US US08/118,775 patent/US5393508A/en not_active Expired - Lifetime
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