WO1995034507A1 - A process for producing soda ash by an ammonia method - Google Patents
A process for producing soda ash by an ammonia method Download PDFInfo
- Publication number
- WO1995034507A1 WO1995034507A1 PCT/RU1994/000137 RU9400137W WO9534507A1 WO 1995034507 A1 WO1995034507 A1 WO 1995034507A1 RU 9400137 W RU9400137 W RU 9400137W WO 9534507 A1 WO9534507 A1 WO 9534507A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- column
- sodium bicarbonate
- liquid
- precarbonized
- stream
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D7/00—Carbonates of sodium, potassium or alkali metals in general
- C01D7/18—Preparation by the ammonia-soda process
Definitions
- the invention relates to the chemical industry, more particularly to a process for producing sodium bicarbonate in the production of soda ash by ammonia method.
- Prior art Known in the art is a process for producing soda ash by an ammonium method comprising carbonising a precarbonized liquid introduced in two streams, the larger one (30-90%) being admitted to the absorbing zone of a carbonization column on to the top absorption tray, and the second stream (10-20%) is admitted into the cooling zone onto the first cooling tray, separating and washing a sodium bicarbonate deposit ( see Romanian Patent No.63189, Int.Class C01 B 31/24, filed on April 26, 1976 and published on February 23, 1978).
- the above-cited process improves the filtration properties of a sodium bicarbonate deposit and the moisture content of the filtered deposit by 17%.
- the above-cited process has a low yield of sodium bicarbonate which is on an average 70 to 72%. This happens because the introduction of a stream of precarbonized liquid to the cooling zone causes the removal of a slurry of sodium bicarbonate from the carbonisation column. The slurry has an insufficient degree of saturation with carbon dioxide on account of a shorter total residence time of this stream in contact with carbon dioxide. Besides, about 10-12% of ammonia is blown out from the precarbonized liquid with unabsorbed carbon dioxide.
- the prior art process is disadvantageous in that it has a low yield of sodium bicarbonate which is about 72% and the poor properties of the slurry due to which fact the mixture content of the filtered sodium bicarbonate deposit is 18.0%.
- the object of the invention is to improve the prior art process so as to increase the yield of sodium bicarbonate and improve the filtration properties of the sodium bicarbonate deposit.
- the object can be attained by using the features set forth in the claims. According to these features, in the claimed process for producing soda ash by an ammonia method comprising carbonizing a precarbonized liquid by introducing it to the absorbing zone of a carbonization column, separating and washing a sodium bicarbonate deposit, the precarbonized liquid is admitted into the absorbing zone of a carbonized column in four uniform streams onto the area below the top absorption tray, the first stream is introduced at a distance of 0.50 diameter of the carbonization column from the top absorption tray and the fourth stream is introduced at a distance of 2.52 diameter of the carbonisation column.
- the claimed process is distinguished from the prior art by feeding a precarbonized liquid to, the absorbing zone of a carbonization column in four uniform streams; by feeding the liquid to the area located below the top absorption tray; by feeding the first stream at a distance of 0.50 diameter of the carbonization column from the top absorption column, and by feeding the fourth stream at a distance of 2.52 diameter of the carbonization column.
- the predominant factor for increasing the yield and production of large crystals of sodium bicarbonate is to distribute the four uniform streams of a precarbonized liquid onto the area located below the top absorption tray, the introduction point of the first and fourth streams being located at distance of 0.50 and 2.52 diameter respectively of the carbonization column.
- the claimed parameters are overlapped, i.e. if the number of the introduction points is reduced to at least four, more particularly to two, the other parameters being constant, this results in withdrawing the gas mixture containing a high ammonia content (due to ammonia being blown out from the liquid to be carbonized with a gas) from the upper portion of the carbonization column.
- the area of the upper portion of the absorbing 2one of the carbonization column selected for the introduction of the precarbonized liquid is essentially determined as the height of the absorbing space of the carbonization column. It was found that this height is the minimum value required for absorbing the carbon dioxide portion by the precarbonized liquid portion and is the optimum value for large well-formed crystals of sodium bicarbonate with a high yield of the latter.
- the yield of sodium bicarbonate is not likely to increase.
- the fourth stream of the precarbonized liquid is introduced to the area located at a distance by more than 2.52 diameter of the carbonization column from the top absorption tray, the filtration properties of sodium bicarbonate become remarkably deteriorated and the designed efficiency of the carbonization column is reduced.
- the influence of the sizes of the area to which a precarbonized liquid is introduced on the main carbonization process parameters are shown in the table.
- the above-listed features are essential, for they exert an influence on the technical result achieved, i.e. the increased yield of sodium bicarbonate and improved filtration properties of the deposit thereof.
- the claimed process is carried out as follows.
- the original stream of a precarbonized liquid is divided into four different streams.
- the precarbonized liquid is fed to four points of the absorbing zone of a carbonisation column through flow rate regulators, the first and fourth streams of the precarbonized liquid are introduced at a distance of 0.50 and 2.52 diameter of the carbonization column respectively from the top absorption tray.
- the first stream introduction gas having a carbon dioxide of 65% by volume is fed in counterflow to the liquid to the lower portion of the carbonization column.
- the second stream introduction gas having a carbon dioxide of 38.0% by volume is fed to the middle portion of the carbonization column.
- Example 1 140 m /hr of a precarbonized liquid is divided into four different streams of 35 m 3 /hr. The precarbonised liquid is fed to four points of the absorbing zone of the carbonization column of 2.8 m in diameter. The first and fourth stream introduction points are located at a distance of 0.50 and 2.52 diameter of the carbonisation column from the top absorption tray which constitutes 1.4 and 7.06 m, respectively for the first and fourth stream introduction points.
- the first stream introduction gas having a carbon dioxide concentration of 65% by volume is fed in counterflow to the liquid to the lower portion of the carbonization column, the second stream introduction gas having a carbon dioxide concentration of 38% by volume is fed to the middle portion of the carbonisation column.
- a sodium bicarbonate slurry is admitted into the cooling zone of the carbonization column from the absorbing zone of the carbonization column, the sodium bicarbonate deposit is separated from the mother liquor and washed.
- the yield of sodium bicarbonate is 74.1% and the moisture content of the deposit after filtration is 15.5%.
- Example 2 The same procedure is carried out as in Example 1, however the first and fourth stream introduction points are located at a distance of 0.86 and 2.18 diameter of the carbonization column, respectively, from the top absorption tray.
- the yield of sodium bicarbonate is 70.5% and the moisture of the sodium bicarbonate deposit after filtration is 17.2%.
- Example 3 The procedure is carried out as in Example 1, however the first and fourth stream introduction points are located at a distance of 0.17 and 2.52 diameter of the carbonisation column from the top absorption tray.
- the yield of sodium bicarbonate is 68.5% and the moisture content of the sodium bicarbonate deposit is 17.9%.
- Example 4 The procedure is carried out as in Example 1, however the first and fourth stream introduction points are located at a distance of 0.5 and 2.85 diameter of the carbonisation column from the top absorption tray.
- the yield of sodium bicarbonate is 68.8%.
- the moisture content of the sodium bicarbonate deposit is 17.5%.
- the invention can be most advantageously used in the chemical industry in the production of soda ash by an ammonia method.
- the claimed process for producing soda ash is advantageous over the prior art process in that the yield of sodium bicarbonate in the claimed process is increased up to 74.1% against 72.0% in the prior art process, thus making it possible to improve the utilisation coefficient of the starting raw material for the production of soda and save the thermal energy required for producing soda; the moisture content of the sodium bicarbonate deposit is lowered to 15.5% against 18.0% in the prior art.
- a lower moisture content in sodium bicarbonate after filtration and washing reduces the heat consumption required for drying sodium bicarbonate and thermal degradation at the subsequent calcination stage.
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to the chemical industry, more particularly to a process for producing sodium bicarbonate in the production of soda ash by an ammonia method. The process for producing soda ash by an ammonia method comprises carbonizing a precarbonized liquid by feeding it into the absorbing zone of a carbonization column, separating and washing a sodium bicarbonate deposit, feeding the precarbonized liquid into the absorbing zone of a carbonization column in four uniform streams below the top absorption tray and the first stream is fed at a distance of 0.5 diameter of the carbonization column from the top absorption tray and the fourth stream at a distance of 2.52 diameter of the carbonization column.
Description
A Process for Producing soda Ash by an Ammonia Method
Field The invention relates to the chemical industry, more particularly to a process for producing sodium bicarbonate in the production of soda ash by ammonia method.
Prior art Known in the art is a process for producing soda ash by an ammonium method comprising carbonising a precarbonized liquid introduced in two streams, the larger one (30-90%) being admitted to the absorbing zone of a carbonization column on to the top absorption tray, and the second stream (10-20%) is admitted into the cooling zone onto the first cooling tray, separating and washing a sodium bicarbonate deposit ( see Romanian Patent No.63189, Int.Class C01 B 31/24, filed on April 26, 1976 and published on February 23, 1978).
The above-cited process improves the filtration properties of a sodium bicarbonate deposit and the moisture content of the filtered deposit by 17%. However the above-cited process has a low yield of sodium bicarbonate which is on an average 70 to 72%. This happens because the introduction of a stream of precarbonized liquid to the cooling zone causes the removal of a slurry of sodium bicarbonate from the carbonisation column. The slurry has an insufficient degree of saturation with carbon dioxide on account of a shorter total residence time of this stream in contact with carbon dioxide. Besides, about 10-12% of ammonia is blown out from the precarbonized liquid with unabsorbed carbon dioxide.
Known in the art is a process for producing soda ash by an ammonia method comprising carbonizing a precarbonized liquid fed to the top absorption column in a single stream, separating and washing a sodium bicarbonate deposit ( see I.N.Fokin and S.A.Krasheninnikov, Technology of Soda, "Khimiya" Publishers, Moscow, 1975, p.76-110). The above-cited process is the closest prior art, since it comprises feeding the whole of a precarbonized liquid into the absorbing zone and does not comprise feeding any other
- 2 - stream to the cooling zone.
The prior art process is disadvantageous in that it has a low yield of sodium bicarbonate which is about 72% and the poor properties of the slurry due to which fact the mixture content of the filtered sodium bicarbonate deposit is 18.0%.
Disclosure The object of the invention is to improve the prior art process so as to increase the yield of sodium bicarbonate and improve the filtration properties of the sodium bicarbonate deposit.
The object can be attained by using the features set forth in the claims. According to these features, in the claimed process for producing soda ash by an ammonia method comprising carbonizing a precarbonized liquid by introducing it to the absorbing zone of a carbonization column, separating and washing a sodium bicarbonate deposit, the precarbonized liquid is admitted into the absorbing zone of a carbonized column in four uniform streams onto the area below the top absorption tray, the first stream is introduced at a distance of 0.50 diameter of the carbonization column from the top absorption tray and the fourth stream is introduced at a distance of 2.52 diameter of the carbonisation column.
No process typical of all the features set forth in the claims have been disclosed in the prior art and hence the claimed process may be regarded as novel.
The claimed process is distinguished from the prior art by feeding a precarbonized liquid to, the absorbing zone of a carbonization column in four uniform streams; by feeding the liquid to the area located below the top absorption tray; by feeding the first stream at a distance of 0.50 diameter of the carbonization column from the top absorption column, and by feeding the fourth stream at a distance of 2.52 diameter of the carbonization column.
The admission of four uniform streams of the precarbonized liquid into the absorbing zone of the
carbonization column makes it possible to improve mass-exchange processes therein and thus to intensify operation of the column of both an absorption and crystallization apparatus and to create the conditions for the greatest saturation of the liquid to be carbonized with carbon dioxide. As a consequence, these conditions allow reducing the amount of ammonia being blown out with an unabsorbed carbonising gas, thus promoting an increased yield of sodium bicarbonate.
It has been found experimentally that the predominant factor for increasing the yield and production of large crystals of sodium bicarbonate is to distribute the four uniform streams of a precarbonized liquid onto the area located below the top absorption tray, the introduction point of the first and fourth streams being located at distance of 0.50 and 2.52 diameter respectively of the carbonization column.
If the claimed parameters are overlapped, i.e. if the number of the introduction points is reduced to at least four, more particularly to two, the other parameters being constant, this results in withdrawing the gas mixture containing a high ammonia content (due to ammonia being blown out from the liquid to be carbonized with a gas) from the upper portion of the carbonization column.
This is the reason why the ammonia content is reduced in the solution which results in decreasing the yield of sodium bicarbonate and also in deteriorating the filtration properties of the slurry and, hence, increasing the moisture content of sodium bicarbonate.
An increase in the number of introduction points of the precarbonized liquid to more than four reduces the residence time of the liquid to be carbonized in the absorbing zone of the carbonisation column and hence makes the liquid less saturated with carbon dioxide; this results in admitting an insufficiently carbonized liquid into the cooling zone of the carbonization column and also decreasing the yield and
Table 6
Influence of the Sizes of the Area to which a Precarbonized Liquid is Introduced
Nos Distance (from column diameter) Yield of sodium Moisture content of Blow-out of of 1st and 4th introduction points bicarbonate, % crystals after ammonia, % of precarbonized liquid from top filtration, % absorption tray
0.52 74.1 6.0
0.84 2.18 70.5 17.2
0.17 2.52 68.5 17.9 8.3
0.5 - 2.35 68.8 18.0 7.1
0.17 2.95 71.3 17.5 9.2
deteriorating the conditions for the formation of sodium bicarbonate crystals. The area of the upper portion of the absorbing 2one of the carbonization column selected for the introduction of the precarbonized liquid is essentially determined as the height of the absorbing space of the carbonization column. It was found that this height is the minimum value required for absorbing the carbon dioxide portion by the precarbonized liquid portion and is the optimum value for large well-formed crystals of sodium bicarbonate with a high yield of the latter.
If the first stream of the precarbonized liquid is introduced to the area located at a distance by less than 0.5 diameter of the carbonization column from the top absorption tray, the yield of sodium bicarbonate is not likely to increase.
If the fourth stream of the precarbonized liquid is introduced to the area located at a distance by more than 2.52 diameter of the carbonization column from the top absorption tray, the filtration properties of sodium bicarbonate become remarkably deteriorated and the designed efficiency of the carbonization column is reduced. The influence of the sizes of the area to which a precarbonized liquid is introduced on the main carbonization process parameters are shown in the table. The above-listed features are essential, for they exert an influence on the technical result achieved, i.e. the increased yield of sodium bicarbonate and improved filtration properties of the deposit thereof.
The prior art solutions have revealed no features identical with those of the distinguishing features, hence the claimed solution meets the inventive level requirements. Preferred Embodiment of the Invention The claimed process is carried out as follows. The original stream of a precarbonized liquid is divided into four different streams. The precarbonized liquid is fed to four points of the absorbing zone of a carbonisation column through flow rate regulators, the first and fourth streams of
the precarbonized liquid are introduced at a distance of 0.50 and 2.52 diameter of the carbonization column respectively from the top absorption tray. The first stream introduction gas having a carbon dioxide of 65% by volume is fed in counterflow to the liquid to the lower portion of the carbonization column. The second stream introduction gas having a carbon dioxide of 38.0% by volume is fed to the middle portion of the carbonization column. After passing through the absorbing zone of the carbonization column, a sodium bicarbonate slurry is cooled in the cooling zone, the sodium bicarbonate slurry is cooled in the cooling zone, the. sodium bicarbonate deposit is separated from the mother liquor and washed. Example 1. 140 m /hr of a precarbonized liquid is divided into four different streams of 35 m3/hr. The precarbonised liquid is fed to four points of the absorbing zone of the carbonization column of 2.8 m in diameter. The first and fourth stream introduction points are located at a distance of 0.50 and 2.52 diameter of the carbonisation column from the top absorption tray which constitutes 1.4 and 7.06 m, respectively for the first and fourth stream introduction points. The first stream introduction gas having a carbon dioxide concentration of 65% by volume is fed in counterflow to the liquid to the lower portion of the carbonization column, the second stream introduction gas having a carbon dioxide concentration of 38% by volume is fed to the middle portion of the carbonisation column. A sodium bicarbonate slurry is admitted into the cooling zone of the carbonization column from the absorbing zone of the carbonization column, the sodium bicarbonate deposit is separated from the mother liquor and washed.
The yield of sodium bicarbonate is 74.1% and the moisture content of the deposit after filtration is 15.5%. Example 2. The same procedure is carried out as in Example 1, however the first and fourth stream introduction points are located at a distance of 0.86 and 2.18 diameter of
the carbonization column, respectively, from the top absorption tray. The yield of sodium bicarbonate is 70.5% and the moisture of the sodium bicarbonate deposit after filtration is 17.2%.
Example 3. The procedure is carried out as in Example 1, however the first and fourth stream introduction points are located at a distance of 0.17 and 2.52 diameter of the carbonisation column from the top absorption tray. The yield of sodium bicarbonate is 68.5% and the moisture content of the sodium bicarbonate deposit is 17.9%.
Example 4. The procedure is carried out as in Example 1, however the first and fourth stream introduction points are located at a distance of 0.5 and 2.85 diameter of the carbonisation column from the top absorption tray. The yield of sodium bicarbonate is 68.8%. The moisture content of the sodium bicarbonate deposit is 17.5%.
Industrial Applicability The invention can be most advantageously used in the chemical industry in the production of soda ash by an ammonia method. The claimed process for producing soda ash is advantageous over the prior art process in that the yield of sodium bicarbonate in the claimed process is increased up to 74.1% against 72.0% in the prior art process, thus making it possible to improve the utilisation coefficient of the starting raw material for the production of soda and save the thermal energy required for producing soda; the moisture content of the sodium bicarbonate deposit is lowered to 15.5% against 18.0% in the prior art. A lower moisture content in sodium bicarbonate after filtration and washing reduces the heat consumption required for drying sodium bicarbonate and thermal degradation at the subsequent calcination stage. These characteristics are supported by the above examples which describe means and methods which help to carry into effect the invention as defined in the claim given below.
Claims
CLAIM A process for producing soda ash by an ammonia method comprising carbonising a precarbonized liquid by feeding it into the absorbing zone of a carbonisation column, separating and washing a sodium bicarbonate deposit, feeding the precarbonized liquid into the absorbing zone of a carbonisation column in four uniform streams below the top absorption column, the first stream being fed at a distance of 0.50 diameter of the carbonisation column from the top absorption tray and the fourth stream at a distance of 2.52 diameter of the carbonisation column.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/RU1994/000137 WO1995034507A1 (en) | 1994-06-15 | 1994-06-15 | A process for producing soda ash by an ammonia method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/RU1994/000137 WO1995034507A1 (en) | 1994-06-15 | 1994-06-15 | A process for producing soda ash by an ammonia method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1995034507A1 true WO1995034507A1 (en) | 1995-12-21 |
Family
ID=20129859
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/RU1994/000137 WO1995034507A1 (en) | 1994-06-15 | 1994-06-15 | A process for producing soda ash by an ammonia method |
Country Status (1)
| Country | Link |
|---|---|
| WO (1) | WO1995034507A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111675227A (en) * | 2020-05-25 | 2020-09-18 | 山东海天生物化工有限公司 | Method for preventing pre-ash barrel from scabbing in distillation process in ammonia-soda process soda ash production |
| CN112694105A (en) * | 2021-01-13 | 2021-04-23 | 河南中源化学股份有限公司 | High-efficient carbonization reaction system |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2866681A (en) * | 1955-05-09 | 1958-12-30 | Chemical Construction Corp | Method and apparatus for the production of sodium bicarbonate |
| SU1721015A1 (en) * | 1989-08-09 | 1992-03-23 | Предприятие П/Я А-3732 | Method for obtaining sodium carbonate |
-
1994
- 1994-06-15 WO PCT/RU1994/000137 patent/WO1995034507A1/en active Application Filing
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2866681A (en) * | 1955-05-09 | 1958-12-30 | Chemical Construction Corp | Method and apparatus for the production of sodium bicarbonate |
| SU1721015A1 (en) * | 1989-08-09 | 1992-03-23 | Предприятие П/Я А-3732 | Method for obtaining sodium carbonate |
Non-Patent Citations (1)
| Title |
|---|
| M.B. ZELIKIN ET AL., Proizvodstvo Kaltsini Rovannoi Sody, 1959, GNTI Khimicheskoi Literatury, (M.), s. 212-215. * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111675227A (en) * | 2020-05-25 | 2020-09-18 | 山东海天生物化工有限公司 | Method for preventing pre-ash barrel from scabbing in distillation process in ammonia-soda process soda ash production |
| CN111675227B (en) * | 2020-05-25 | 2022-06-07 | 山东海天生物化工有限公司 | Method for preventing pre-ash barrel from scabbing in distillation process in ammonia-soda process soda ash production |
| CN112694105A (en) * | 2021-01-13 | 2021-04-23 | 河南中源化学股份有限公司 | High-efficient carbonization reaction system |
| CN112694105B (en) * | 2021-01-13 | 2023-11-17 | 河南中源化学股份有限公司 | High-efficiency carbonization reaction system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3933977A (en) | Process for producing sodium carbonate | |
| EA015121B1 (en) | Process and apparatus for conversion of biomass | |
| EP0029536A1 (en) | Process for removing and recovering ammonia from aqueous liquors | |
| US4421536A (en) | Process for producing krypton and xenon | |
| CA2136235C (en) | Method for purification of acetonitrile | |
| CN111634928A (en) | Method for preparing large-particle baking soda by secondary carbonization method and baking soda obtained by method | |
| CN115744934A (en) | Preparation method for producing electronic-grade sodium fluoride by purifying industrial-grade sodium carbonate | |
| US3932584A (en) | Method for purifying hydrogen sulfide-containing gas | |
| US3321268A (en) | Conversion of caustic soda to soda ash | |
| US2368901A (en) | Ammonium sulphate production | |
| WO1995034507A1 (en) | A process for producing soda ash by an ammonia method | |
| US5413635A (en) | Lime sludge treatment process | |
| SU1819854A1 (en) | Method of sodium hydrocarbonate producing | |
| US4569832A (en) | Method and apparatus for desulfurizing coke oven gases | |
| US4020148A (en) | Process for drying sodium carbonate peroxide | |
| CN107827896B (en) | Process method and equipment for co-producing hexamethylenetetramine by using melamine tail gas | |
| US4206187A (en) | Process for removing sulfur dioxide from gas | |
| US1372193A (en) | Manufacture of calcium carbonate | |
| US4049787A (en) | Process for separating sulphur in the form of hydrogen sulphide from clarified green liquor obtained from the combustion of waste liquor | |
| US3687624A (en) | Process for recovering sulfur dioxide from a gas containing same | |
| US4000034A (en) | Kraft mill recovery system | |
| RU2209181C2 (en) | Method of carbonization of ammoniated brine in production of soda ash ammonial method and carbonization column for method embodiment | |
| RU2039008C1 (en) | Ammonia method of producing calcined soda | |
| RU2055017C1 (en) | Carbon dioxide production method | |
| RU2381177C2 (en) | Method for production of soda ash by ammoniac method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| AK | Designated states |
Kind code of ref document: A1 Designated state(s): BG JP PL RO |
|
| AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE |
|
| DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
| 121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
| 122 | Ep: pct application non-entry in european phase |