CA2170599A1 - Process for producing granulated sodium percarbonate - Google Patents
Process for producing granulated sodium percarbonateInfo
- Publication number
- CA2170599A1 CA2170599A1 CA002170599A CA2170599A CA2170599A1 CA 2170599 A1 CA2170599 A1 CA 2170599A1 CA 002170599 A CA002170599 A CA 002170599A CA 2170599 A CA2170599 A CA 2170599A CA 2170599 A1 CA2170599 A1 CA 2170599A1
- Authority
- CA
- Canada
- Prior art keywords
- nozzle
- central tube
- fluidised bed
- sodium percarbonate
- solution
- 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.)
- Abandoned
Links
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
- B05B7/02—Spray pistols; Apparatus for discharge
- B05B7/06—Spray pistols; Apparatus for discharge with at least one outlet orifice surrounding another approximately in the same plane
- B05B7/061—Spray pistols; Apparatus for discharge with at least one outlet orifice surrounding another approximately in the same plane with several liquid outlets discharging one or several liquids
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B15/00—Peroxides; Peroxyhydrates; Peroxyacids or salts thereof; Superoxides; Ozonides
- C01B15/055—Peroxyhydrates; Peroxyacids or salts thereof
- C01B15/10—Peroxyhydrates; Peroxyacids or salts thereof containing carbon
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D1/00—Evaporating
- B01D1/16—Evaporating by spraying
- B01D1/20—Sprayers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
- B01J2/02—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic by dividing the liquid material into drops, e.g. by spraying, and solidifying the drops
- B01J2/04—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic by dividing the liquid material into drops, e.g. by spraying, and solidifying the drops in a gaseous medium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
- B01J2/16—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic by suspending the powder material in a gas, e.g. in fluidised beds or as a falling curtain
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B15/00—Peroxides; Peroxyhydrates; Peroxyacids or salts thereof; Superoxides; Ozonides
- C01B15/055—Peroxyhydrates; Peroxyacids or salts thereof
- C01B15/10—Peroxyhydrates; Peroxyacids or salts thereof containing carbon
- C01B15/103—Peroxyhydrates; Peroxyacids or salts thereof containing carbon containing only alkali metals as metals
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Detergent Compositions (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Glanulating (AREA)
- Medicinal Preparation (AREA)
Abstract
Sodium percarbonate of the formula 2 Na2CO3 be produced by fluidised-bed spray granulation by spraying an aqueous solution of sodium carbonate and a hydrogen peroxide solution on sodium percarbonate seeds and evaporating water. The previously necessary use of phosphorous-containing crystallisation inhibitor to prevent blockages and incrustations in and on the nozzle can be avoided by the invention if the solutions are sprayed using a single threesubstance pulverisation nozzle with the external mixing of the solutions.
Description
217059~
, WO 95/06615 PCT/EP94/01270 Specification This invention relates to a process for the production of granulated sodium percarbonate by fluidised bed spray granulation.
Various processing principles are known for the production of sodium percarbonate of the formula 2 Na2CO3 3 H2O2: (i) reaction of hydrogen peroxide with sodium carbonate in the aqueous phase, crystallisation of the sodium percarbonate and separation thereof from the mother liquor; (ii) reaction of solid soda with aqueous hydrogen peroxide;
(iii) fluidised bed spray granulation, wherein a hydrogen peroxide solution and a soda solution are sprayed in a fluidised bed apparatus onto sodium percarbonate nuclei and water is simultaneously evaporated. While the processing principle according to (i) is used on an industrial scale, auxiliary substances such as sodium chloride for salting out and metaphosphates to control crystallisation are, however, necessary and purification and/or partial discharge of the mother liquor is required in order to achieve good product quality. Due to irregularities and unsatisfactory storage stability, the quality of the sodium percarbonate produced using processing principle (ii) does not generally approach that of sodium percarbonate produced according to (i) or (iii).
Processes according to principle (iii) are attracting increasing interest as they give rise to no waste water and also result in an abrasion-resistant sodium percarbonate at very high yield. German patent 20 60 971 teaches such a ` 21705~3 Wo 95/06615 PCT/EP94/01270 process: in this process, a sodium percarbonate solution or sodium percarbonate suspension or separately and simultaneously an aqueous hydrogen peroxide solution and an aqueous sodium carbonate solution are continuously introduced into a fluidised bed which contains sodium percarbonate nuclei, the ~;m~n~ions of which are smaller than those of the granulate particles to be produced, and water is continuously evaporated from the aqueous medium containing sodium percarbonate and granulate particles of a certain size are removed from the fluidised bed. When a sodium percarbonate solution or an H2O2 solution and an Na2CO3 solution are used, nuclei are simultaneously fed into the fluidised bed.
The above-stated process exhibits a series of disadvantages: in one embodiment a sodium percarbonate solution or suspension must first be produced, which entails an additional process stage. Introducing a sodium percarbonate suspension or a supersaturated sodium percarbonate solution into a fluidised bed is liable to be troublesome because the spray nozzle used rapidly becomes plugged. On the other hand, if a dilute sodium percarbonate solution is used much water must be vaporised, so raising costs.
German patent 27 33 935 points out problems associated with another embodiment disclosed in DE 20 60 971 C3: when an aqueous hydrogen peroxide solution and an aqueous sodium carbonate solution are sprayed through two separate spray nozzles, such as conventional two-fluid nozzles for spraying a solution, using air as the propellant gas, it is difficult to achieve sufficiently intimate mixing of the two solutions in the fluidised bed, a feature which is however necessary in order to obtain homogeneous sodium percarbonate particles. However, if the two solutions are together introduced into the fluidised bed through a single spray nozzle, crystallisation occurs in the spray nozzle, ._ generally after a short period of operation, which gives rise to plugging and results in downtime.
In order to eliminate the above-stated problems, it is 5 proposed in DE 27 33 935 C2 to use a common spray nozzle for both solutions and, in order to avoid plugging of the spray nozzle, to dissolve a metaphosphate in at least one of the two solutions. The two solutions are mixed within or at the inlet of the spray nozzle. The quantity of 10 metaphosphate used is conveniently between 0.1 and 20 g per kg of sodium percarbonate.
On the one hand, the additional use of a metaphosphate in the process of DE 27 33 935 C2 increases raw material costs 15 and, on the other hand, the phosphate introduced into the sodium percarbonate and thus into the detergents, bleaches and cleaning products containing the sodium percarbonate, is a component in which there is increasing interest in eliminating for environmental reasons.
The object of the present invention is thus to provide a process for the production of granulated sodium percarbonate of the formula 2 Na2CO3 3 H2O2 by fluidised bed spray granulation, wherein an aqueous hydrogen peroxide 25 solution and an aqueous sodium carbonate solution are sprayed using a single spray nozzle into a fluidised bed containing nuclei, the dimensions of which are smaller than those of the granulate particles to be produced, and water is simultaneously evaporated at a fluidised bed temperature 30 in the range from 40 to 95C, which process does not exhibit the disadvantages of the process known from DE
27 33 935 C2.
This object is achieved by using a three-fluid atomising 35 nozzle with external mixing of the solutions for spraying the two solutions, to which no crystallisation inhibitor containing phosphorus is added.
~ WO 95/06615 2170 5 ~ 3 PCT/EP94/01270 A three-fluid atomising nozzle comprising a nozzle body and a nozzle mouthpiece is conveniently used, the nozzle mouthpiece of which has a central tube and two jacket tubes arranged coaxially around the central tube, wherein one of the solutions is introduced into the central tube and one into the annular gap formed between the central tube and the inner jacket tube and a propellant gas is introduced into the outer annular gap formed between the jacket tubes.
According to a particularly preferred embodiment, a three-fluid atomising nozzle of the above-stated type is used having a central tube which, at the nozzle tip, extends beyond the end of the jacket tubes by at least one radius of the central tube.
By using a three-fluid atomising nozzle with external m;x;ng, the two solutions each conta;n;ng one reactant are sprayed into the fluidised bed by means of a single nozzle, wherein mixing of the two solutions and, thereafter, formation of the sodium percarbonate, occur outside the nozzle before the water evaporates from the liquid droplets. Sodium percarbonate particles of a homogeneous structure are obtained in this manner without the nozzle becoming plugged. By using a nozzle with a nozzle mouthpiece-according to the invention and in particular such a nozzle with an extended central tube, it is possible to avoid encrustation on the nozzle tip and so possibly to avoid operational stoppages even after an extended period of operation. Simultaneously, it is possible to dispense with the use of a metaphosphate or another crystallisation inhibitor containing phosphorus, such that the granulated sodium percarbonate produced is substantially free of phosphorus compounds. A very low phosphorus content in the sodium percarbonate is not excluded in the event that hydrogen peroxide stabilised with phosphates, as is commercially conventional, is used.
The basic principle of the three-fluid atomising nozzle is similar to that known for conventional commercial two-fluid WO 95/06615 217 0 5 ~ 9 pcT/Epg4/ol27o nozzles, but it additionally contains devices for introducing and guiding the second liquid into the nozzle.
The nozzle thus comprises a nozzle body with separate channels and connections for the media and a nozzle mouthpiece with the features according to the claims.
Figures 1 and 2 illustrate the structure of a convenient three-fluid atomising nozzle; the particularly preferred arrangement of the nozzle mouthpiece is simultaneously shown: figure 1 shows a longitudinal section of a particularly preferred three-fluid atomising nozzle; figure 2 shows a cross-section through the plane A-B shown in figure 1:
A nozzle body (1) is connected to a nozzle mouthpiece (2) in such a manner that the liquid media to be conveyed do not come into contact with each other until they are outside the nozzle. The connection between (1) and (2) may take the form of a plug, bayonet or screw fixing or sleeves or the like. In the preferred embodiment according to figure 1, the jacket tubes ~11) and (12) of the nozzle mouthpiece are connected to the nozzle body by means of screw threads (9a and b). The nozzle body contains the connections (3) and (4) for the two liquids and (5) for the propellant gas, together with the separate channels (6) and (7) for the two liquids and (8) for the propellant gas.
The nozzle mouthpiece (1) comprises a central tube (10) and two jacket tubes (11) and (12) arranged coaxially around the central tube. The central tube (10) is connected with channel (7); in figure 1, channel (7) and the central tube (10) take the form of a continuous tube. The annular gap (13) formed between the central tube (10) and the inner jacket tube (11) is connected with channel (6) and the annular gap (14) formed between the inner (11) and outer (12) jacket tube is connected with channel (8). An essential feature of a particularly preferred embodiment is the central tube extension (15), which extends beyond the ends of the jacket tubes at the nozzle tip. One or both jacket tubes and the central tube may taper inwards towards the nozzle tip ((17a) and (17b) in figure 1) in order to increase the exit velocity of the media and to promote break up of the liquid stream and propellant gas stream exiting from the annular gaps. The central tube (10) or its extension (15) and/or one or both of the annular gaps may additionally contain swirl inducers (16a and b). The propellant for the nozzle may be air or another inert gas, such as for example nitrogen or also superheated steam.
According to a preferred embodiment of the nozzle, the central tube of the nozzle mouthpiece extends beyond the ends of the jacket tubes by at least one radius of the central tube, preferably by 2 to 10, in particular 3 to 6 radii of the central tube. The jacket tubes preferably end at the same level. The jacket tubes may, however, also end at different levels, but the central tube extension according to the claims must be longer than both jacket tubes. Provided that the outer jacket tube extends beyond the inner jacket tube, the liquid in the annular gap and the propellant gas are premixed within the nozzle, but the liquids themselves do not come into contact with each other until they are outside the nozzle. The optimum size of the central tube extension is dependent upon the radius of the central tube and the flow area of the inner annular gap at the outlet. As the central tube radius increases, it is generally favourable to shorten the central tube extension;
at a central tube radius of, for example, at least-2 mm, the central tube extension will generally be between 3 and 5 central tube radii.
In principle, the aqueous H2O2 solution or the Na2CO3 solution may be conveyed through the central tube of the nozzle and the other solution may be conveyed through the adjacent annular gap. Preferably, however, the solution present in the smaller volume (at preferred solution WO 95/06615 2170 5 ~ 9 PCT/EP94/01270 -concentrations, this will be the hydrogen peroxide solution) is passed through the central tube.
The aqueous hydrogen peroxide solution and the aqueous sodium carbonate solution are introduced into the fluidised bed maintained in an apparatus for fluidised bed spray granulation in a ratio such that the molar ratio of Na2CO3 to H2O2 is in the range between 1:1.4 and 1:1.7; a molar ratio of 1:1.5 and 1:1.65 is preferred.
The concentration of the solutions may vary over a broad range; the highest possible concentration is preferably selected in order to keep the quantity of water to be evaporated low. According to a particularly preferred embodiment, the Na2CO3 solution and the H2O2 solution will have a very high concentration, so that the sodium percarbonate solution initially present in droplet form in the mixing-zone in front of the nozzle tip is supersaturated. The aqueous hydrogen peroxide solution conventionally contains from 30 to 75 wt.~, preferably 40 to 70 wt.~, of H2O2. The Na2CO3 concentration of the sodium carbonate solution is conveniently above 10 wt.~ of Na2CO3, preferably between 20 wt.~ and the saturation concentration at the particular temperature; Na2CO3 concentration is particularly preferably 30 wt.~. One or both solutions, but preferably the soda solution, may be used in preheated form at 30 to 70C, instead of at a conventional storage temperature.
Reference is made to the cited prior art documents with regard to performance of fluidised bed spray granulation.
In the case of continuous operation, a sufficient number of nuclei must always be present in the fluidised bed. In order to control grain size distribution, between 0 and 30 kg, preferably between 1 and 10 kg of nuclei are introduced into the fluidised bed per 100 kg of granulated sodium percarbonate discharged from the fluidised bed. The weight of nuclei is determined by the desired grain size ` WO 95/06615 217 0 5 9 3 PCT/EPg4/01270 -range and in particular by the size of the nuclei. It is necessary to optimise operating conditions with regard to the introduction of nuclei at a given desired fluidised bed temperature in order to achieve steady state operation.
Recirculating an excessively large quantity of very finely divided material as nuclei may result in excessively low particle growth, while an excessively high moisture content in the fluidised bed may result in unwanted aggregation.
Reference is made to the article by H. Uhlemann in Chem.-10 Ing. Technik 62 (1990), no. 10, pp. 822-834 with regard to the general technique of fluidised bed spray granulation, the mutual interaction of operating parameters and control of particle size and distribution and to suitable equipment for continuous fluidised bed spray granulation.
The temperature of the fluidised bed is maintained between 40 and 95C, preferably between 40 and 80C and in particular between 50 and 70C.
The temperature of the inlet air for drying and maintaining the fluidised bed is adjusted to above 120C, preferably between 200 and 400C and in particular between 300 and 400C. The person skilled in the art will adjust the temperature and mass flux of the inlet air in such a manner that a well fluidised bed is produced, the required performance may be achieved and an excessively large quantity of product need not be returned from a downstream dust separator. The velocity of the drying air in the empty tube is conventionally between 1 and 4 m/s. The fluidised bed apparatus is generally operated in such a manner that approximately standard pressure (around 1 bar) prevails in the area of the fluidised bed; it is, however, also possible to operate at a pressure below or above standard pressure. One or more three-fluid atomising nozzles may be arranged in the fluidised bed spray granulation unit, wherein the direction of spraying may be substantially cocurrent or countercurrent to the stream of drying air or may assume an intermediate position.
- Wo 95/06615 21705 9 9 PCT/EP94/01270 g It has proved convenient in the case of continuous operation to discharge the sodium percarbonate at a residual moisture content of up to 10 wt.~, preferably of between 3 and 9 wt.~ and in particular between 5 and 8 wt.~
and, if desired, to dry it in a downstream apparatus to the residual moisture content of the conventional commercial product (below 1 wt.~) or to pass it on for post-treatment. Post-treatments which may in particular be considered are processes for providing a shell around the particles for the purpose of increasing storage stability.
Such post-treatment is preferably baæed on applying solutions cont~ining one or more shell components, such as for example boron compounds, soda, sodium sulphate, magnesium sulphate and water glass onto the previously produced granulated sodium percarbonate in a fluidised bed while simultaneously evaporating water and forming a firmly attached outer shell.
If required, the H2O2 solution and/or Na2CO3 solution to be sprayed may also contain additives (with the exception of crystallisation inhibitors containing phosphorus) in order to influence product properties and in particular to increase the active oxygen stability of the hydrogen peroxide used and of the sodium percarbonate to be produced. Stabilising additives which may be considered are preferably magnesium salts (conventionally added to the H2O2 solution in sulphate form) and water glass (usually added to the soda solution); further additives may be, for example, stannates, complexing agents and dipicolinic acid.
While phosphorus-free crystallisation inhibitors may be present, they are not conventionally used. Speed of dissolution may, for example, be increased by adding surface-active substances.
The apparatus for fluidised bed spray granulation may be those as are described in DE 27 33 935, EP o 332 929 B1 and in the already cited article by H. Uhlemann. The fluidised bed may be equipped with one or preferably with two or more three-fluid atomising nozzles according to the invention.
Apparatus having an inlet for nuclei and a classifying granulate outlet is preferred. The nuclei to be introduced into the fluidised bed may originate from dust separation, screening and/or partial comminution.
In addition to the above-stated apparatus having a steady state fluidised bed, the process may also be performed in a fluidised bed flow channel, which is equipped with one or more nozzles arranged in series; the product is classified at the end of the flow channel and undersized product, optionally together with comminuted oversized product, is returned to the flow channel.
Although the process of the invention is preferably performed continuously on an industrial scale, i.e. with continuous introduction of the solutions and discharge of the granulated product of the desired size, it may also be operated discontinuously (spraying terminated once the desired grain size range has been achieved and the granulated product is then discharged).
It is possible by means of the process according to the invention to obtain granulated sodium percarbonate starting from a hydrogen peroxide solution and a sodium carbonate solution by fluidised bed spray granulation on an industrial scale without stoppages due to plugging or encrustation of the nozzles in a virtually quantitative yield with an elevated active oxygen content, elevated abrasion resistance, elevated bulk density and very good storage stability without there being any need to use crystallisation inhibitors. In order to increase stability, the product obtainable according to the invention may, immediately after production, be enclosed in a shell in a manner known per se, wherein due to the dense and substantially spherical structure of the grains, a smaller quantity of shell material than is required for enclosing Wo 95/06615 217 05 9 9 PCT/EP94/01270 sodium percarbonate obtained by crystallisation processes in a shell is sufficient.
It could not be predicted that it would be possible by using a three-fluid atomising nozzle according to the invention not only to achieve adequate external mixing of the solutions and to obtain a homogeneous product, but also to dispense with a crystallisation inhibitor containing phosphorus; operating costs are thus reduced and an environmental problem is avoided. It was moreover not to be expected that by using a three-fluid atomising nozzle with a central tube extension it would be possible virtually completely to avoid stoppages due to encrustation on the nozzle.
Examples An aqueous hydrogen peroxide solution and an aqueous sodium percarbonate solution, which contained no crystallisation inhibitors, were introduced into a fluidised bed using air as the propellant in an apparatus for fluidised bed spray granulation with devices for dust recirculation and the introduction of nuclei and a classifying granulate outlet, once an initially introduced quantity of sodium percarbonate had been fluidised. The nozzles were located within the fluidised bed and the direction of spraying was cocurrent with the stream of drying gas. The central tube extension was 3 central tube radii in length, the jacket tubes ended at the same level.
The table shows the essential operating parameters and material data for the sodium percarbonate produced. Even after several days' continuous operation, there was no plugging or encrustation in or around the nozzle.
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l WO 95/06615 217 0~ 9 9 PCT/EP94/01270 _ List of reference numbers 1 Nozzle body 2 Nozzle mouthpiece 3 Connection for liquid (i) 4 Connection for liquid (ii) Connection for propellant gas 6 Channel for liquid (i) 7 Channel for liquid (ii) 8 Channel for propellant gas 9a Thread 9b Thread Central tube 11 Jacket tube (inner) 12 Jacket tube (outer) 13 Annular gap for liquid (i) 14 Annular gap for propellant gas Central tube extension 16a Swirl inducer 16b Swirl inducer 17a Taper 17b Taper
, WO 95/06615 PCT/EP94/01270 Specification This invention relates to a process for the production of granulated sodium percarbonate by fluidised bed spray granulation.
Various processing principles are known for the production of sodium percarbonate of the formula 2 Na2CO3 3 H2O2: (i) reaction of hydrogen peroxide with sodium carbonate in the aqueous phase, crystallisation of the sodium percarbonate and separation thereof from the mother liquor; (ii) reaction of solid soda with aqueous hydrogen peroxide;
(iii) fluidised bed spray granulation, wherein a hydrogen peroxide solution and a soda solution are sprayed in a fluidised bed apparatus onto sodium percarbonate nuclei and water is simultaneously evaporated. While the processing principle according to (i) is used on an industrial scale, auxiliary substances such as sodium chloride for salting out and metaphosphates to control crystallisation are, however, necessary and purification and/or partial discharge of the mother liquor is required in order to achieve good product quality. Due to irregularities and unsatisfactory storage stability, the quality of the sodium percarbonate produced using processing principle (ii) does not generally approach that of sodium percarbonate produced according to (i) or (iii).
Processes according to principle (iii) are attracting increasing interest as they give rise to no waste water and also result in an abrasion-resistant sodium percarbonate at very high yield. German patent 20 60 971 teaches such a ` 21705~3 Wo 95/06615 PCT/EP94/01270 process: in this process, a sodium percarbonate solution or sodium percarbonate suspension or separately and simultaneously an aqueous hydrogen peroxide solution and an aqueous sodium carbonate solution are continuously introduced into a fluidised bed which contains sodium percarbonate nuclei, the ~;m~n~ions of which are smaller than those of the granulate particles to be produced, and water is continuously evaporated from the aqueous medium containing sodium percarbonate and granulate particles of a certain size are removed from the fluidised bed. When a sodium percarbonate solution or an H2O2 solution and an Na2CO3 solution are used, nuclei are simultaneously fed into the fluidised bed.
The above-stated process exhibits a series of disadvantages: in one embodiment a sodium percarbonate solution or suspension must first be produced, which entails an additional process stage. Introducing a sodium percarbonate suspension or a supersaturated sodium percarbonate solution into a fluidised bed is liable to be troublesome because the spray nozzle used rapidly becomes plugged. On the other hand, if a dilute sodium percarbonate solution is used much water must be vaporised, so raising costs.
German patent 27 33 935 points out problems associated with another embodiment disclosed in DE 20 60 971 C3: when an aqueous hydrogen peroxide solution and an aqueous sodium carbonate solution are sprayed through two separate spray nozzles, such as conventional two-fluid nozzles for spraying a solution, using air as the propellant gas, it is difficult to achieve sufficiently intimate mixing of the two solutions in the fluidised bed, a feature which is however necessary in order to obtain homogeneous sodium percarbonate particles. However, if the two solutions are together introduced into the fluidised bed through a single spray nozzle, crystallisation occurs in the spray nozzle, ._ generally after a short period of operation, which gives rise to plugging and results in downtime.
In order to eliminate the above-stated problems, it is 5 proposed in DE 27 33 935 C2 to use a common spray nozzle for both solutions and, in order to avoid plugging of the spray nozzle, to dissolve a metaphosphate in at least one of the two solutions. The two solutions are mixed within or at the inlet of the spray nozzle. The quantity of 10 metaphosphate used is conveniently between 0.1 and 20 g per kg of sodium percarbonate.
On the one hand, the additional use of a metaphosphate in the process of DE 27 33 935 C2 increases raw material costs 15 and, on the other hand, the phosphate introduced into the sodium percarbonate and thus into the detergents, bleaches and cleaning products containing the sodium percarbonate, is a component in which there is increasing interest in eliminating for environmental reasons.
The object of the present invention is thus to provide a process for the production of granulated sodium percarbonate of the formula 2 Na2CO3 3 H2O2 by fluidised bed spray granulation, wherein an aqueous hydrogen peroxide 25 solution and an aqueous sodium carbonate solution are sprayed using a single spray nozzle into a fluidised bed containing nuclei, the dimensions of which are smaller than those of the granulate particles to be produced, and water is simultaneously evaporated at a fluidised bed temperature 30 in the range from 40 to 95C, which process does not exhibit the disadvantages of the process known from DE
27 33 935 C2.
This object is achieved by using a three-fluid atomising 35 nozzle with external mixing of the solutions for spraying the two solutions, to which no crystallisation inhibitor containing phosphorus is added.
~ WO 95/06615 2170 5 ~ 3 PCT/EP94/01270 A three-fluid atomising nozzle comprising a nozzle body and a nozzle mouthpiece is conveniently used, the nozzle mouthpiece of which has a central tube and two jacket tubes arranged coaxially around the central tube, wherein one of the solutions is introduced into the central tube and one into the annular gap formed between the central tube and the inner jacket tube and a propellant gas is introduced into the outer annular gap formed between the jacket tubes.
According to a particularly preferred embodiment, a three-fluid atomising nozzle of the above-stated type is used having a central tube which, at the nozzle tip, extends beyond the end of the jacket tubes by at least one radius of the central tube.
By using a three-fluid atomising nozzle with external m;x;ng, the two solutions each conta;n;ng one reactant are sprayed into the fluidised bed by means of a single nozzle, wherein mixing of the two solutions and, thereafter, formation of the sodium percarbonate, occur outside the nozzle before the water evaporates from the liquid droplets. Sodium percarbonate particles of a homogeneous structure are obtained in this manner without the nozzle becoming plugged. By using a nozzle with a nozzle mouthpiece-according to the invention and in particular such a nozzle with an extended central tube, it is possible to avoid encrustation on the nozzle tip and so possibly to avoid operational stoppages even after an extended period of operation. Simultaneously, it is possible to dispense with the use of a metaphosphate or another crystallisation inhibitor containing phosphorus, such that the granulated sodium percarbonate produced is substantially free of phosphorus compounds. A very low phosphorus content in the sodium percarbonate is not excluded in the event that hydrogen peroxide stabilised with phosphates, as is commercially conventional, is used.
The basic principle of the three-fluid atomising nozzle is similar to that known for conventional commercial two-fluid WO 95/06615 217 0 5 ~ 9 pcT/Epg4/ol27o nozzles, but it additionally contains devices for introducing and guiding the second liquid into the nozzle.
The nozzle thus comprises a nozzle body with separate channels and connections for the media and a nozzle mouthpiece with the features according to the claims.
Figures 1 and 2 illustrate the structure of a convenient three-fluid atomising nozzle; the particularly preferred arrangement of the nozzle mouthpiece is simultaneously shown: figure 1 shows a longitudinal section of a particularly preferred three-fluid atomising nozzle; figure 2 shows a cross-section through the plane A-B shown in figure 1:
A nozzle body (1) is connected to a nozzle mouthpiece (2) in such a manner that the liquid media to be conveyed do not come into contact with each other until they are outside the nozzle. The connection between (1) and (2) may take the form of a plug, bayonet or screw fixing or sleeves or the like. In the preferred embodiment according to figure 1, the jacket tubes ~11) and (12) of the nozzle mouthpiece are connected to the nozzle body by means of screw threads (9a and b). The nozzle body contains the connections (3) and (4) for the two liquids and (5) for the propellant gas, together with the separate channels (6) and (7) for the two liquids and (8) for the propellant gas.
The nozzle mouthpiece (1) comprises a central tube (10) and two jacket tubes (11) and (12) arranged coaxially around the central tube. The central tube (10) is connected with channel (7); in figure 1, channel (7) and the central tube (10) take the form of a continuous tube. The annular gap (13) formed between the central tube (10) and the inner jacket tube (11) is connected with channel (6) and the annular gap (14) formed between the inner (11) and outer (12) jacket tube is connected with channel (8). An essential feature of a particularly preferred embodiment is the central tube extension (15), which extends beyond the ends of the jacket tubes at the nozzle tip. One or both jacket tubes and the central tube may taper inwards towards the nozzle tip ((17a) and (17b) in figure 1) in order to increase the exit velocity of the media and to promote break up of the liquid stream and propellant gas stream exiting from the annular gaps. The central tube (10) or its extension (15) and/or one or both of the annular gaps may additionally contain swirl inducers (16a and b). The propellant for the nozzle may be air or another inert gas, such as for example nitrogen or also superheated steam.
According to a preferred embodiment of the nozzle, the central tube of the nozzle mouthpiece extends beyond the ends of the jacket tubes by at least one radius of the central tube, preferably by 2 to 10, in particular 3 to 6 radii of the central tube. The jacket tubes preferably end at the same level. The jacket tubes may, however, also end at different levels, but the central tube extension according to the claims must be longer than both jacket tubes. Provided that the outer jacket tube extends beyond the inner jacket tube, the liquid in the annular gap and the propellant gas are premixed within the nozzle, but the liquids themselves do not come into contact with each other until they are outside the nozzle. The optimum size of the central tube extension is dependent upon the radius of the central tube and the flow area of the inner annular gap at the outlet. As the central tube radius increases, it is generally favourable to shorten the central tube extension;
at a central tube radius of, for example, at least-2 mm, the central tube extension will generally be between 3 and 5 central tube radii.
In principle, the aqueous H2O2 solution or the Na2CO3 solution may be conveyed through the central tube of the nozzle and the other solution may be conveyed through the adjacent annular gap. Preferably, however, the solution present in the smaller volume (at preferred solution WO 95/06615 2170 5 ~ 9 PCT/EP94/01270 -concentrations, this will be the hydrogen peroxide solution) is passed through the central tube.
The aqueous hydrogen peroxide solution and the aqueous sodium carbonate solution are introduced into the fluidised bed maintained in an apparatus for fluidised bed spray granulation in a ratio such that the molar ratio of Na2CO3 to H2O2 is in the range between 1:1.4 and 1:1.7; a molar ratio of 1:1.5 and 1:1.65 is preferred.
The concentration of the solutions may vary over a broad range; the highest possible concentration is preferably selected in order to keep the quantity of water to be evaporated low. According to a particularly preferred embodiment, the Na2CO3 solution and the H2O2 solution will have a very high concentration, so that the sodium percarbonate solution initially present in droplet form in the mixing-zone in front of the nozzle tip is supersaturated. The aqueous hydrogen peroxide solution conventionally contains from 30 to 75 wt.~, preferably 40 to 70 wt.~, of H2O2. The Na2CO3 concentration of the sodium carbonate solution is conveniently above 10 wt.~ of Na2CO3, preferably between 20 wt.~ and the saturation concentration at the particular temperature; Na2CO3 concentration is particularly preferably 30 wt.~. One or both solutions, but preferably the soda solution, may be used in preheated form at 30 to 70C, instead of at a conventional storage temperature.
Reference is made to the cited prior art documents with regard to performance of fluidised bed spray granulation.
In the case of continuous operation, a sufficient number of nuclei must always be present in the fluidised bed. In order to control grain size distribution, between 0 and 30 kg, preferably between 1 and 10 kg of nuclei are introduced into the fluidised bed per 100 kg of granulated sodium percarbonate discharged from the fluidised bed. The weight of nuclei is determined by the desired grain size ` WO 95/06615 217 0 5 9 3 PCT/EPg4/01270 -range and in particular by the size of the nuclei. It is necessary to optimise operating conditions with regard to the introduction of nuclei at a given desired fluidised bed temperature in order to achieve steady state operation.
Recirculating an excessively large quantity of very finely divided material as nuclei may result in excessively low particle growth, while an excessively high moisture content in the fluidised bed may result in unwanted aggregation.
Reference is made to the article by H. Uhlemann in Chem.-10 Ing. Technik 62 (1990), no. 10, pp. 822-834 with regard to the general technique of fluidised bed spray granulation, the mutual interaction of operating parameters and control of particle size and distribution and to suitable equipment for continuous fluidised bed spray granulation.
The temperature of the fluidised bed is maintained between 40 and 95C, preferably between 40 and 80C and in particular between 50 and 70C.
The temperature of the inlet air for drying and maintaining the fluidised bed is adjusted to above 120C, preferably between 200 and 400C and in particular between 300 and 400C. The person skilled in the art will adjust the temperature and mass flux of the inlet air in such a manner that a well fluidised bed is produced, the required performance may be achieved and an excessively large quantity of product need not be returned from a downstream dust separator. The velocity of the drying air in the empty tube is conventionally between 1 and 4 m/s. The fluidised bed apparatus is generally operated in such a manner that approximately standard pressure (around 1 bar) prevails in the area of the fluidised bed; it is, however, also possible to operate at a pressure below or above standard pressure. One or more three-fluid atomising nozzles may be arranged in the fluidised bed spray granulation unit, wherein the direction of spraying may be substantially cocurrent or countercurrent to the stream of drying air or may assume an intermediate position.
- Wo 95/06615 21705 9 9 PCT/EP94/01270 g It has proved convenient in the case of continuous operation to discharge the sodium percarbonate at a residual moisture content of up to 10 wt.~, preferably of between 3 and 9 wt.~ and in particular between 5 and 8 wt.~
and, if desired, to dry it in a downstream apparatus to the residual moisture content of the conventional commercial product (below 1 wt.~) or to pass it on for post-treatment. Post-treatments which may in particular be considered are processes for providing a shell around the particles for the purpose of increasing storage stability.
Such post-treatment is preferably baæed on applying solutions cont~ining one or more shell components, such as for example boron compounds, soda, sodium sulphate, magnesium sulphate and water glass onto the previously produced granulated sodium percarbonate in a fluidised bed while simultaneously evaporating water and forming a firmly attached outer shell.
If required, the H2O2 solution and/or Na2CO3 solution to be sprayed may also contain additives (with the exception of crystallisation inhibitors containing phosphorus) in order to influence product properties and in particular to increase the active oxygen stability of the hydrogen peroxide used and of the sodium percarbonate to be produced. Stabilising additives which may be considered are preferably magnesium salts (conventionally added to the H2O2 solution in sulphate form) and water glass (usually added to the soda solution); further additives may be, for example, stannates, complexing agents and dipicolinic acid.
While phosphorus-free crystallisation inhibitors may be present, they are not conventionally used. Speed of dissolution may, for example, be increased by adding surface-active substances.
The apparatus for fluidised bed spray granulation may be those as are described in DE 27 33 935, EP o 332 929 B1 and in the already cited article by H. Uhlemann. The fluidised bed may be equipped with one or preferably with two or more three-fluid atomising nozzles according to the invention.
Apparatus having an inlet for nuclei and a classifying granulate outlet is preferred. The nuclei to be introduced into the fluidised bed may originate from dust separation, screening and/or partial comminution.
In addition to the above-stated apparatus having a steady state fluidised bed, the process may also be performed in a fluidised bed flow channel, which is equipped with one or more nozzles arranged in series; the product is classified at the end of the flow channel and undersized product, optionally together with comminuted oversized product, is returned to the flow channel.
Although the process of the invention is preferably performed continuously on an industrial scale, i.e. with continuous introduction of the solutions and discharge of the granulated product of the desired size, it may also be operated discontinuously (spraying terminated once the desired grain size range has been achieved and the granulated product is then discharged).
It is possible by means of the process according to the invention to obtain granulated sodium percarbonate starting from a hydrogen peroxide solution and a sodium carbonate solution by fluidised bed spray granulation on an industrial scale without stoppages due to plugging or encrustation of the nozzles in a virtually quantitative yield with an elevated active oxygen content, elevated abrasion resistance, elevated bulk density and very good storage stability without there being any need to use crystallisation inhibitors. In order to increase stability, the product obtainable according to the invention may, immediately after production, be enclosed in a shell in a manner known per se, wherein due to the dense and substantially spherical structure of the grains, a smaller quantity of shell material than is required for enclosing Wo 95/06615 217 05 9 9 PCT/EP94/01270 sodium percarbonate obtained by crystallisation processes in a shell is sufficient.
It could not be predicted that it would be possible by using a three-fluid atomising nozzle according to the invention not only to achieve adequate external mixing of the solutions and to obtain a homogeneous product, but also to dispense with a crystallisation inhibitor containing phosphorus; operating costs are thus reduced and an environmental problem is avoided. It was moreover not to be expected that by using a three-fluid atomising nozzle with a central tube extension it would be possible virtually completely to avoid stoppages due to encrustation on the nozzle.
Examples An aqueous hydrogen peroxide solution and an aqueous sodium percarbonate solution, which contained no crystallisation inhibitors, were introduced into a fluidised bed using air as the propellant in an apparatus for fluidised bed spray granulation with devices for dust recirculation and the introduction of nuclei and a classifying granulate outlet, once an initially introduced quantity of sodium percarbonate had been fluidised. The nozzles were located within the fluidised bed and the direction of spraying was cocurrent with the stream of drying gas. The central tube extension was 3 central tube radii in length, the jacket tubes ended at the same level.
The table shows the essential operating parameters and material data for the sodium percarbonate produced. Even after several days' continuous operation, there was no plugging or encrustation in or around the nozzle.
., ~ C~ i o ~ o o o o V
o, C~l o F
o o u~
O~ a) c O O ~
F ~ , -- ,~ O,~ ~ Q
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Q ~ c~ ~ ~ o -- -- ~ o - ~ o ~ ~ - - o ~ ~ ~ ~ ~
~ o ~ o ~ ~
Z _ C ~ ' C
Q
~ O ,o s~ ~C~ o o ~ ~ c o C I ~ ~ ~ d- ~~ ~) In ~~D _ c ~ ~ C ~ w W o s -- -- OO O ~ U~ ~ ~ Z -- W 0 ~
O -- ---- -- C~l ~ ~ C~l ~ Z ~ ~ o 0 ~ 3 C 0 a~
W o ~ o o m cQ ~ ~ ~ ~ oo ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
-- In ~ ul ~ u~Is~ ~ ls) ~ ~ c O ~ ~, r O O OO O O O O ~ ~ ,. ", Q C
Q O O OO O O O O,~ ' ~ --Q ~ W C
--o ~- X X XX X X ~ C W O
CC (~ o ~_ Q Q QQ Q Q
QIL Q Q QQ . . QCL
CC W WW W W W
W
l WO 95/06615 217 0~ 9 9 PCT/EP94/01270 _ List of reference numbers 1 Nozzle body 2 Nozzle mouthpiece 3 Connection for liquid (i) 4 Connection for liquid (ii) Connection for propellant gas 6 Channel for liquid (i) 7 Channel for liquid (ii) 8 Channel for propellant gas 9a Thread 9b Thread Central tube 11 Jacket tube (inner) 12 Jacket tube (outer) 13 Annular gap for liquid (i) 14 Annular gap for propellant gas Central tube extension 16a Swirl inducer 16b Swirl inducer 17a Taper 17b Taper
Claims (7)
- Claims Process for the production of granulated sodium percarbonate of the formula 2 Na2CO3 3 H2O2 by fluidised bed spray granulation, wherein an aqueous hydrogen peroxide solution and an aqueous sodium carbonate solution are sprayed by means of a three-fluid atomising nozzle comprising a nozzle body and a nozzle mouthpiece with external mixing of the solutions into a fluidised bed containing nuclei, the dimensions of which are smaller than those of the granulate particles to be produced, and water is simultaneously evaporated at a fluidised bed temperature in the range from 40 to 95°C, characterised in that a three-fluid atomising nozzle is used, the nozzle mouthpiece of which has a central tube and two jacket tubes arranged coaxially around the central tube and the central tube of which, at the nozzle tip, extends beyond the end of the jacket tubes by at least one radius of the central tube, and that one of the solutions is introduced into the central tube and one is introduced into the annular gap formed between the central tube and the inner jacket tube and a propellant gas is introduced into the outer annular gap formed between the jacket tubes.
- 2. Process according to claim 1, characterised in that a three-fluid atomising nozzle is used, the central tube of which nozzle mouthpiece extends beyond the end of the jacket tubes by 2 to 10, in particular by 3 to 6 radii of the central tube.
- 3. Process according to one of claims 1 or 2, characterised in that an aqueous hydrogen peroxide solution with an H2O2 content of 40 to 70 wt.% and an aqueous sodium percarbonate solution with an Na2CO3 content of 20 wt.%
up to the saturation concentration are used. - 4. Process according to one of claims 1 to 3, characterised in that the temperature of the fluidised bed is maintained in the range from 50 to 70°C.
- 5. Process according to one of claims 1 to 4, characterised in that spray granulation is performed in a continuously operated fluidised bed apparatus with an inlet for nuclei and a classifying granulate outlet.
- 6. Process according to one of claims 1 to 5, characterised in that granulated sodium percarbonate of the desired grain size is discharged from the fluidised bed apparatus at a moisture content of between 2 and 10 wt.% and, if required, is post-dried or passed for post-treatment in order to increase stability.
- 7. Process according to one of claims 1 to 6, characterised in that an aqueous soda solution and an aqueous hydrogen peroxide solution are introduced into the spray nozzle in a molar ratio of soda to H2O2 of 1:1.5 to 1:1.65.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4329205.4 | 1993-08-31 | ||
| DE4329205A DE4329205C2 (en) | 1993-08-31 | 1993-08-31 | Process for the production of granular sodium percarbonate |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2170599A1 true CA2170599A1 (en) | 1995-03-09 |
Family
ID=6496387
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002170599A Abandoned CA2170599A1 (en) | 1993-08-31 | 1994-04-23 | Process for producing granulated sodium percarbonate |
Country Status (22)
| Country | Link |
|---|---|
| EP (1) | EP0716640B1 (en) |
| JP (1) | JP2801406B2 (en) |
| KR (1) | KR100190471B1 (en) |
| CN (1) | CN1132499A (en) |
| AT (1) | ATE153637T1 (en) |
| AU (1) | AU6647894A (en) |
| BR (1) | BR9407374A (en) |
| CA (1) | CA2170599A1 (en) |
| CO (1) | CO4180442A1 (en) |
| CZ (1) | CZ49896A3 (en) |
| DE (2) | DE4329205C2 (en) |
| ES (1) | ES2103589T3 (en) |
| FI (1) | FI960938A (en) |
| HR (1) | HRP940483A2 (en) |
| HU (1) | HUT73680A (en) |
| IL (1) | IL110819A0 (en) |
| PL (1) | PL313288A1 (en) |
| SK (1) | SK26796A3 (en) |
| TR (1) | TR28528A (en) |
| TW (1) | TW269674B (en) |
| WO (1) | WO1995006615A1 (en) |
| ZA (1) | ZA946621B (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1728762A1 (en) * | 2005-06-01 | 2006-12-06 | SOLVAY (Société Anonyme) | Coated sodium percarbonate particles, process for their preparation, their use and detergent compositions containing them |
| US7435714B2 (en) | 2002-12-20 | 2008-10-14 | Evonik Degussa Gmbh | Liquid detergent and cleaning agent composition comprising a multi-coated bleach particle |
| US7588697B2 (en) | 2003-05-07 | 2009-09-15 | Evonik Degussa Gmbh | Coated sodium percarbonate granules with improved storage stability |
| US7718592B2 (en) | 2004-11-11 | 2010-05-18 | Degussa, Gmbh | Sodium percarbonate particles having a shell layer comprising thiosulfate |
| US7956027B2 (en) | 2006-07-27 | 2011-06-07 | Evonik Degussa Gmbh | Coated sodium percarbonate particles |
| US8153576B2 (en) | 2006-07-27 | 2012-04-10 | Evonik Degussa Gmbh | Coated sodium percarbonate particles |
| US8658590B2 (en) | 2006-07-27 | 2014-02-25 | Evonik Degussa Gmbh | Coated sodium percarbonate particles |
| US8945671B2 (en) | 2007-12-19 | 2015-02-03 | Evonik Treibacher Gmbh | Method for producing encapsulated sodium percarbonate particles |
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|---|---|---|---|---|
| DE19514187C1 (en) † | 1995-04-21 | 1996-05-15 | Degussa | Process and device for producing granules by fluidized bed spray granulation |
| DE19534274A1 (en) * | 1995-09-15 | 1997-03-20 | Degussa | Process for reducing the dissolution time in the production and / or coating of sodium percarbonate |
| DE19544293C2 (en) | 1995-11-28 | 1998-01-29 | Degussa | Encased sodium percarbonate particles and their use |
| DE19600018A1 (en) | 1996-01-03 | 1997-07-10 | Henkel Kgaa | Detergent with certain oxidized oligosaccharides |
| DE19603849C1 (en) | 1996-02-05 | 1997-08-21 | Glatt Ingtech Gmbh | Process for the production of sodium percarbonate in granular form |
| DE19717729A1 (en) * | 1997-04-26 | 1998-10-29 | Degussa | Coated sodium percarbonate particles, process for their preparation and their use |
| DE10048514A1 (en) * | 2000-09-29 | 2002-04-11 | Degussa | Sodium percarbonate fluidized bed granulate and process for its production |
| DE10065953A1 (en) | 2000-12-23 | 2002-07-04 | Degussa | Process for increasing the internal stability of sodium percarbonate |
| DE10138927A1 (en) * | 2001-08-08 | 2003-02-20 | Glatt Ingtech Gmbh | Fluidized bed process to make granular solids from spray-injected fluid ingredients in stoichiometric ratio, comprises introducing ingredients from below into fluid be in which number of chemical reactants are introduced by jet |
| DE10140838A1 (en) | 2001-08-21 | 2003-03-06 | Degussa | Process for the production of sodium percarbonate |
| ITMI20012693A1 (en) * | 2001-12-19 | 2003-06-19 | Zambon Spa | SPRAY UNIT OF A SPRAY DRYER |
| CN100368282C (en) * | 2006-09-20 | 2008-02-13 | 山东天力干燥设备有限公司 | Sodium percarbonate dry method granulation processes and apparatus thereof |
| EP1905738A1 (en) * | 2006-09-28 | 2008-04-02 | Evonik Degussa GmbH | Process for preparing granular sodium percarbonate |
| EP2048112A1 (en) * | 2007-10-09 | 2009-04-15 | Kemira Kemi AB | Use of a nozzle for manufacturing sodium percarbonate |
| PL2361964T3 (en) | 2010-02-25 | 2013-05-31 | Procter & Gamble | Detergent composition |
| DE102010028236A1 (en) | 2010-04-27 | 2011-10-27 | Evonik Degussa Gmbh | Bleaching agent particles comprising sodium percarbonate and a bleach activator |
| CN102211761B (en) * | 2011-04-11 | 2012-11-21 | 边文阳 | Method for preparing sodium peroxocarbonate by spray drying method and preparation system and application thereof |
| DE102013211093A1 (en) | 2013-06-14 | 2014-12-18 | Evonik Treibacher Gmbh | Encased sodium percarbonate particles |
| KR102232413B1 (en) * | 2014-06-16 | 2021-03-26 | 코웨이 주식회사 | Apparatus for purifying water with co2 gas provider |
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| CN107999302A (en) * | 2017-12-27 | 2018-05-08 | 上海格拉曼国际消防装备有限公司 | A kind of flusher for multi-component reaction type depressor |
| DE102019211958A1 (en) * | 2019-08-08 | 2021-02-11 | Glatt Ingenieurtechnik Gesellschaft mit beschränkter Haftung | Process for the production of fertilizer granules |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL6900961A (en) * | 1969-01-21 | 1970-07-23 | Dry-granulated ammonium salts | |
| DD107426A1 (en) * | 1973-10-23 | 1974-08-05 | ||
| LU75466A1 (en) * | 1976-07-27 | 1978-02-08 |
-
1993
- 1993-08-31 DE DE4329205A patent/DE4329205C2/en not_active Expired - Fee Related
-
1994
- 1994-04-23 CA CA002170599A patent/CA2170599A1/en not_active Abandoned
- 1994-04-23 CN CN94193580A patent/CN1132499A/en active Pending
- 1994-04-23 BR BR9407374A patent/BR9407374A/en not_active IP Right Cessation
- 1994-04-23 HU HU9600510A patent/HUT73680A/en unknown
- 1994-04-23 AT AT94915105T patent/ATE153637T1/en active
- 1994-04-23 ES ES94915105T patent/ES2103589T3/en not_active Expired - Lifetime
- 1994-04-23 PL PL94313288A patent/PL313288A1/en unknown
- 1994-04-23 SK SK267-96A patent/SK26796A3/en unknown
- 1994-04-23 JP JP7507888A patent/JP2801406B2/en not_active Expired - Fee Related
- 1994-04-23 DE DE59402931T patent/DE59402931D1/en not_active Expired - Lifetime
- 1994-04-23 EP EP94915105A patent/EP0716640B1/en not_active Expired - Lifetime
- 1994-04-23 WO PCT/EP1994/001270 patent/WO1995006615A1/en not_active Application Discontinuation
- 1994-04-23 CZ CZ96498A patent/CZ49896A3/en unknown
- 1994-04-23 AU AU66478/94A patent/AU6647894A/en not_active Abandoned
- 1994-04-23 KR KR1019960701100A patent/KR100190471B1/en not_active IP Right Cessation
- 1994-07-05 TW TW083106129A patent/TW269674B/zh active
- 1994-07-14 CO CO94030865A patent/CO4180442A1/en unknown
- 1994-08-26 TR TR00852/94A patent/TR28528A/en unknown
- 1994-08-30 ZA ZA946621A patent/ZA946621B/en unknown
- 1994-08-30 HR HRP4329205.4A patent/HRP940483A2/en not_active Application Discontinuation
- 1994-08-30 IL IL11081994A patent/IL110819A0/en unknown
-
1996
- 1996-02-28 FI FI960938A patent/FI960938A/en unknown
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7435714B2 (en) | 2002-12-20 | 2008-10-14 | Evonik Degussa Gmbh | Liquid detergent and cleaning agent composition comprising a multi-coated bleach particle |
| US7588697B2 (en) | 2003-05-07 | 2009-09-15 | Evonik Degussa Gmbh | Coated sodium percarbonate granules with improved storage stability |
| US7718592B2 (en) | 2004-11-11 | 2010-05-18 | Degussa, Gmbh | Sodium percarbonate particles having a shell layer comprising thiosulfate |
| EP1728762A1 (en) * | 2005-06-01 | 2006-12-06 | SOLVAY (Société Anonyme) | Coated sodium percarbonate particles, process for their preparation, their use and detergent compositions containing them |
| WO2006128901A1 (en) * | 2005-06-01 | 2006-12-07 | Solvay (Société Anonyme) | Coated sodium percarbonate particles, process for their production, their use and detergent compositions containing them |
| US7956027B2 (en) | 2006-07-27 | 2011-06-07 | Evonik Degussa Gmbh | Coated sodium percarbonate particles |
| US8153576B2 (en) | 2006-07-27 | 2012-04-10 | Evonik Degussa Gmbh | Coated sodium percarbonate particles |
| US8658590B2 (en) | 2006-07-27 | 2014-02-25 | Evonik Degussa Gmbh | Coated sodium percarbonate particles |
| US8945671B2 (en) | 2007-12-19 | 2015-02-03 | Evonik Treibacher Gmbh | Method for producing encapsulated sodium percarbonate particles |
Also Published As
| Publication number | Publication date |
|---|---|
| CO4180442A1 (en) | 1995-06-07 |
| PL313288A1 (en) | 1996-06-24 |
| DE59402931D1 (en) | 1997-07-03 |
| JP2801406B2 (en) | 1998-09-21 |
| DE4329205A1 (en) | 1995-03-02 |
| HUT73680A (en) | 1996-09-30 |
| CZ49896A3 (en) | 1996-07-17 |
| ES2103589T3 (en) | 1997-09-16 |
| CN1132499A (en) | 1996-10-02 |
| KR960704796A (en) | 1996-10-09 |
| HRP940483A2 (en) | 1996-10-31 |
| WO1995006615A1 (en) | 1995-03-09 |
| FI960938A (en) | 1996-04-25 |
| SK26796A3 (en) | 1996-07-03 |
| DE4329205C2 (en) | 1996-05-23 |
| IL110819A0 (en) | 1994-11-11 |
| BR9407374A (en) | 1996-07-16 |
| HU9600510D0 (en) | 1996-04-29 |
| ZA946621B (en) | 1995-04-03 |
| TW269674B (en) | 1996-02-01 |
| JPH09501140A (en) | 1997-02-04 |
| KR100190471B1 (en) | 1999-06-01 |
| EP0716640B1 (en) | 1997-05-28 |
| ATE153637T1 (en) | 1997-06-15 |
| EP0716640A1 (en) | 1996-06-19 |
| AU6647894A (en) | 1995-03-22 |
| TR28528A (en) | 1996-09-30 |
| FI960938A0 (en) | 1996-02-28 |
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