Method of producing granular sodium percarbonate

FIELD: chemistry.

SUBSTANCE: invention can be used in production of detergents and bleaching agents. Granular sodium percarbonate is obtained through granulation in a fluidised bed which contains sodium percarbonate particles, into which aqueous hydrogen peroxide solution and aqueous sodium carbonate solution are sprayed through at least one multi-component nozzle with external mixing, with simultaneous evaporation of water. The sodium carbonate solution additionally contains sodium carbonate and/or sodium percarbonate in suspended form. Before feeding into the multi-component nozzle, the sodium carbonate solution is passed through a mechanical disperser to disperse solid substances using shearing force created between the stator and the rotor.

EFFECT: invention enables to avoid clogging of multi-component nozzles and return dust-like sodium percarbonate, separated from the stream going out of the fluidised gas layer, into the granulation process.

5 cl, 2 ex

 

The present invention relates to a method for producing granulated percarbonate sodium by (durastically) granulation in the fluidized bed with a possibility of sodium carbonate and/or percarbonate sodium in suspended form in the spray nozzle without the risk of clogging.

Percarbonate sodium finds wide application as having bleaching action of the component in detergents and cleaning agents. To apply for these purposes, percarbonate sodium must have in the composition of detergents sufficient stability (resistance) during storage, because otherwise, when the storage containing detergents can result in the loss of active oxygen loss as a result percarbonate sodium its bleaching action. Percarbonate sodium sensitive to contact with moisture under the influence of which it decomposes in the composition of the detergents with the loss of active oxygen. Therefore, for the manufacture of detergents or cleaning agents percarbonate sodium is usually used in the form of particles in the shell, which protects covered with it particles of percarbonate sodium from moisture. The use of granulated percarbonate sodium can cover its particles are effective shell already when the flow rate is considerable quantities forming its material.

Granulated percarbonate sodium with a smooth surface of the granules, especially suitable for coating the shell, you can get known from WO 95/06615 way granulation in the fluidized bed. Upon receipt of the granulated percarbonate sodium this way, an aqueous solution of hydrogen peroxide and aqueous sodium carbonate solution is sprayed through a multicomponent nozzle with external mixing in containing particles of percarbonate sodium fluidized bed with simultaneous evaporation of water. In sputtered multicomponent nozzle jet conical mixing of the hydrogen peroxide solution and sodium carbonate solution are formed droplets of the solution percarbonate sodium, usually saturated. In the fluidized bed these droplets collide with particles of percarbonate sodium, which precipitates from solution percarbonate sodium and with the surfaces of which are made with these aqueous solutions of the water evaporates under the effect of siraudeau gas fed to create a fluidized bed. However, the disadvantage of this known method consists in the necessity of evaporation of relatively large quantities of water. In addition, due to the abrasion of the particles in the fluidized bed, and also because of the undesirable drying of the droplets prior to their collision with the particles percarbonate sodium is formed is Lavigny percarbonate sodium, out of the fluidized bed siraudin gas.

Formed with the exhaust from the fluidized bed gas pulverized percarbonate sodium does not meet the requirements for its application in the detergent composition, and for this reason it far back in the production cycle, adding in the process of preparation of a solution of sodium carbonate. Similarly to the process cycle can be returned and pulverized percarbonate sodium with other stages of the technological process, for example, from the stage of the coating or from the pneumatic supply system of particles percarbonate sodium. However, a significant part associated pulverized percarbonate sodium peroxide is lost through decomposition in alkaline solution of sodium carbonate.

In EP 0787682 A1 to reduce the amount of water evaporated was asked to serve in a multicomponent nozzle is not the solution, and a suspension of sodium carbonate. Together with a suspension of sodium carbonate or spray air additionally you can also submit crystalline percarbonate sodium. However, the disadvantage described in EP 0787682 A1 method is a rapid clogging of nozzles already after a short time of their work, as it was established in experiments in connection with the filing in EB is Pascoe patent office of opposition to grant of patent EP 0787682 B1.

Given the above, in this area there remains a need to develop a method of producing granulated percarbonate sodium by granulation in the fluidized bed with the possibility of filing herewith sodium carbonate and in suspended form in the spray nozzle without the risk of clogging. Equally there is also a need return pulverized percarbonate sodium in the production cycle without loss thus associated in percarbonate sodium peroxide for use in the process of obtaining the desired granulated percarbonate sodium.

With the invention it was found that the above problems can be solved using the method of producing granulated percarbonate sodium by granulation in containing particles of percarbonate sodium fluidized bed, in which via at least one multi-component nozzle with external mixing spray an aqueous solution of hydrogen peroxide and an aqueous solution of sodium carbonate with simultaneous evaporation of water, and the solution of sodium carbonate, optionally containing sodium carbonate and/or percarbonate sodium in suspended form, before serving in multi-component nozzle is passed through a dispersant for dispersing solids.

Upon receipt of the pellet is consistent of percarbonate sodium proposed in the invention method using an aqueous solution of hydrogen peroxide, preferably the hydrogen peroxide is from 30 to 75 wt.%, particularly preferably from 40 to 70 wt.%. Additionally, the hydrogen peroxide solution may also contain a stabilizing percarbonate sodium, respectively, the content of active oxygen supplements. As such enhance the stability of percarbonate sodium additives, it is preferable to use the alkali metal silicates, primarily silicate, magnesium salts, stannate, pyrophosphates, polyphosphates, and chelating agents from the group hydroxycarbonic acids, aminocarbonyl acids, aminophosphonic acids, phosphonocarboxylate acids and hydroxyphosphonic acids, as well as their salts with alkali metals, ammonium and magnesium salts.

Upon receipt of the granulated percarbonate sodium proposed in the invention method is used, in addition, an aqueous solution of sodium carbonate, optionally containing sodium carbonate, percarbonate sodium or both of these substances in suspended form. The number of suspended sodium carbonate, respectively percarbonate sodium, you can choose within a wide range, provided that the slurry remains fluid and retains the ability to pumping. Additionally aqueous solution of sodium carbonate may also contain stabilizing percarbonate sodium additives is, preferably one of these in the previous paragraph additives. In the sodium carbonate solution containing the suspended percarbonate sodium coming from the next stage of the coating or from the pneumatic supply system coated particles percarbonate sodium, in this case, there may be some amount submitted with this percarbonate sodium forming the shell material.

Upon receipt of the granulated percarbonate sodium proposed in the invention by way of an aqueous solution of sodium carbonate, optionally containing sodium carbonate, percarbonate sodium or both of these substances in suspended form, prior to being fed into the spray nozzle is passed through a dispersant for dispersing solids. For use as a dispersant suitable for all devices that provide uniform distribution of particles of sodium carbonate, respectively percarbonate sodium in the sodium carbonate solution with the simultaneous destruction of agglomerates of particles of sodium carbonate or particles percarbonate sodium. As an example, suitable for use in these purposes, the dispersant can be called ultrasonic dispersers. Preferably, however, use dispersers mechanical action, based on, for example, on the impact of the var is girugamesh materials or the creation of shear forces. Particularly preferred dispersant in which the shear force applied to the suspension, is created between the rotor and stator. As examples of the dispersing agents of this type that can be used to obtain granulated percarbonate sodium proposed in the invention method can be called stream dispersant (dispersant continuous action) constructive series Ultra-Turrax®and Dispax®manufactured by IKA.

The parameters of the dispersant and his work should preferably be such that it ensures the destruction or fragmentation present in the slurry of agglomerates, the diameter of which more than a third higher than the minimum pipe size used in the multi-component nozzle. When the flow of the suspension through the Central channel of the multi-component nozzles specified minimum pipe size corresponds to the minimum diameter of the Central channel. When applying the same suspension through the annular channel multi-component nozzles specified minimum pipe size corresponds to the minimum width of the annular gap that forms this annular channel.

The sodium carbonate solution with suspended particles of sodium carbonate and/or percarbonate sodium preferably continuously pass through the disperser and immediately after exit and who to serve in multi-component nozzle. Filtered through the dispersant slurry can simultaneously serve several multicomponent nozzles.

In one of the preferred embodiments of the invention, the dispersant is dispersed solid sodium carbonate and/or solid percarbonate sodium in an aqueous solution of sodium carbonate. This solid material is fed into the sodium carbonate solution and was dispersed in this solution in the same apparatus. As examples of the dispersing agents suitable for use in this embodiment of the invention, can be called inline dispersers constructive series MHD manufactured by IKA.

The sodium carbonate solution may further comprise a stabilizing percarbonate sodium supplements, which you can use the same additives as in the hydrogen peroxide solution.

Both of the solution, i.e. the hydrogen peroxide solution and passed through a disperser of the sodium carbonate solution with suspended particles of sodium carbonate and/or percarbonate sodium, served in one or more multi-component nozzles passing through separate channels, the output of which is an external mixture of both of these solutions in a spray nozzle jet is conical. In the spray nozzle, respectively, in each spray nozzle predpochtitelnei this additionally fed through another it provided for the channel of the spray gas. The corresponding multi-component nozzle with one or two channels for the spray gas is known from WO 95/06615 and EP 0787682 A1. As a sputtering gas, it is preferable to use the air.

Quantitative consumption of hydrogen peroxide solution and quantitative consumption of the sodium carbonate solution with suspended particles of sodium carbonate and/or percarbonate sodium is preferable to choose such that the molar ratio between sodium carbonate and hydrogen peroxide was preferably from 1:1.4 to 1:1,7, particularly preferably from 1:1.5 to 1:1,65. The specified molar ratio refers to the total number of dissolved and suspended sodium carbonate, but excluding suspended percarbonate sodium. The temperature of both solutions should preferably be from 20 to 70°C.

The hydrogen peroxide solution and sodium carbonate solution with suspended particles of sodium carbonate and/or percarbonate sodium multicomponent spray nozzle in containing particles of percarbonate sodium fluidized bed. The commonly used multi-component nozzles can be placed at this over the fluidized bed or within the fluidized bed. To shorten the way that the formed droplets must pass to particle fluidized bed, and in beanie spray drying droplets of multicomponent nozzles preferably within the fluidized bed.

Fluidized bed create and maintain in the fluidized state by filing siraudeau gas, which also intensifies the evaporation of water. Siaosi gas preferably be submitted in a fluidized bed temperature in the range from 120 to 500°C., particularly preferably from 200 to 500°C., especially from 300 to 500°C. Temperature and flow siraudeau gas is chosen so as to allow evaporation of a predominant part of all made with solutions of water. Temperature and flow siraudeau gas is preferable to choose those which allow to maintain the temperature in the fluidized bed in the range from 40 to 95°C., particularly preferably from 50 to 80°C., especially from 60 to 80°C.

Upon receipt of the granulated percarbonate sodium proposed in the invention method, the above solutions can be sprayed in a fluidized bed in a continuous or periodic mode. Preferably also continuously spraying two solutions in a fluidized bed and continuously to take away from him the obtained granulate. The obtained granulate is preferably selected from the fluidized bed sorting through the discharge device, which allows you to return the granule diameter is too small back in the fluidized bed.

In the initial phase of granulation in pseudowire the second layer of the first form of small particles, employees centres granulometry, which are then sprayed with the above solutions. As such centers granulometry it is preferable to use particles percarbonate sodium that are smaller in size, which must be obtained granulate. Continuous granulation in the fluidized bed therein to form granules should always be new centers of granulometry. Such centers granulometry can be formed within the fluidized bed as a result of abrasion of the formed granules or crushing. More preferably, however, feeding centers granulometry in solid form in a fluidized bed from the outside to control the rate of formation of centers granulometry and thus particle size distribution of the obtained granules.

In the process of granulation in the fluidized bed from him siraudin gas are ejected fine, dust-like particles percarbonate sodium. Such particles can be separated from the exhaust flow of the fluidized bed gas with suitable for this purpose device or separators, such as scrubbers, filters or cyclones. Such particles after their separation in solid form in the form of dust from the exhaust of the fluidized bed gas is preferably fully or partially podawa the ü in the dispersant and dispersing in a solution of sodium carbonate, supplied in multi-component nozzle.

The advantage of the invention method before known from EP 0787682 A1 method lies in the possibility of continuous receipt of granulated percarbonate sodium for a long period of time without danger of clogging of the multi-component nozzle. In addition, we offer in the invention, the solution enables more uniform in comparison with the known from EP 0787682 A1 way to spray containing solids solution of sodium carbonate, as these particles do not get stuck in the hole of the spray nozzle, the spray of which jet is conical eliminated thereby the uneven distribution of solid particles. The associated positive effect is the ability to achieve nearly complete conversion of hydrogen peroxide in percarbonate sodium when using hydrogen peroxide in a smaller excess.

In the variant with return pulverized particles percarbonate sodium, separated from the flow of exhaust from the fluidized bed gas disperser proposed in the invention method allows you to return this pulverized percarbonate sodium in the production cycle without loss contained in the bound form of hydrogen peroxide. This enables you to convert large quantities use the th of hydrogen peroxide in the product granulated percarbonate sodium homogeneous quality. Return pulverized percarbonate sodium in the production cycle is not detrimental to the quality of the obtained granulated percarbonate sodium.

Examples

Example 1: the Dispersion of the sodium carbonate solution with suspended particles percarbonate sodium with and without the use of dispersant

30%by weight soda solution was applied with a flow rate of 300 l/h through a flow disperser type MHD 2000/5 company IKA in the three-component jet model 0/56 S3 firm Schlick and sprayed without spraying gas. In the dispersant double row dispersing the working body of the rotor-stator type with width of the gap between the teeth 3 mm soda solution was dispersively pulverized percarbonate sodium with an average particle size of 45 μm in the amount of 80-150 kg/h Spray nozzle worked during 4 h without clogging and formed uniformly sprayed a jet of conical shape.

In a comparative experiment, instead of dispersing the working body used to not having a dispersing effect suspendisse working body. After a short period of time due to partial clogging of the gap junction channel injector was beginning to form irregular, intermittent spray jet conical shape.

Example 2: Return pulverized percarbonate in the process Gras is ulali in the fluidized bed

Powdered percarbonate sodium with an average particle size of 45 μm, separated from the stream of exhaust gas of an industrial plant for producing granulated percarbonate sodium, dispersively with a flow rate of 100 kg/h as described in example 1, the equipment 30%by weight soda solution, supplied with a flow rate of 280 l/h, and then filed in a three-component nozzle of the industrial installation. Through this three-component nozzle using air as the spray gas in a fluidized bed created in the industrial setting, was spraying the resulting suspension, and 44%by mass hydrogen peroxide solution with a flow rate of 90 l/h after a 3-day period three-component nozzle no its clogging was not observed. According to the results of the analysis of quantitative (material) balance setup it was found that more than 50% returned to the process cycle pulverized percarbonate sodium joined the obtained granulated percarbonate sodium.

Return pulverized percarbonate sodium cycle had no effect on the particle size of the obtained granulated percarbonate sodium and abrasion resistance.

1. A method of obtaining a granulated percarbonate sodium by granulation in containing particles Parker is onata sodium fluidized bed, in which via at least one multi-component nozzle with external mixing spray an aqueous solution of hydrogen peroxide and an aqueous solution of sodium carbonate with simultaneous evaporation of water, characterized in that the sodium carbonate solution, optionally containing sodium carbonate and/or percarbonate sodium in suspended form, before serving in multi-component nozzle is passed through a dispersant for dispersing solids.

2. The method according to claim 1, characterized in that the dispersant use mechanical action.

3. The method according to claim 2, characterized in that the dispersant to the slurry applied shear force generated between the rotor and stator.

4. The method according to one of claims 1 to 3, characterized in that the dispersant is dispersed solid sodium carbonate and/or solid percarbonate sodium in an aqueous solution of sodium carbonate.

5. The method according to claim 4, characterized in that the exhaust flow from the fluidized bed gas separating percarbonate sodium in the form of dust and separated pulverized percarbonate sodium fully or partially served in the disperser.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: sodium percarbonate particles covered by a cladding have a core of sodium percarbonate obtained via fluidised bed granulation. The cladding contains sodium sulphate and sodium carbonate in weight ratio ranging from 95:5 to 75:25 in relative amount of at least 80 wt %.

EFFECT: improved detergent action of sodium percarbonate when used as detergent component with simultaneous increase in stability when stored with detergents.

12 cl, 5 tbl

FIELD: chemistry.

SUBSTANCE: sodium percarbonate particles are covered by a cladding which contains sodium sulphate in form of a high-temperature phase of sodium sulphate and/or in form of a high-temperature phase of a double salt of formula Na4(SO4)1+n(CO3)1-n, where n is a number ranging from 0 to 0.5.

EFFECT: high stability during storage.

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SUBSTANCE: sodium percarbonate particles are covered by a cladding which contains anhydrous sodium sulphate in amount of 70-99.8 wt % and sodium borate in amount of 0.2-20 wt % and where said cladding accounts for 1-10% of the total weight of one particle of sodium percarbonate.

EFFECT: high stability during storage when using sodium percarbonate particles as a component of detergent and cleaning agents.

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FIELD: chemistry.

SUBSTANCE: invention relates to sodium percarbonate particles. Essence of invention: described are particles of sodium percarbonate, provided with coating and consisting of main particles of sodium percarbonate, surrounded with at least one layer of coating, possessing long storage stability, expressed as amount of released heat at 40°C, measured after 12-week long storage at temperature 40°C, which constitutes less than 5 mcW/g. Subject of invention also are sodium percarbonate particles, provide with coating and consisting of main particles of sodium percarbonate, surrounded with at least, one layer of coating, possessing long storage stability, expressed as preservation of available oxygen content after 8-week long storage at temperature 55°C, which constitutes at least 70%. Also subject of invention are method of said sodium percarbonate particles production and application of said particles in detergent compositions as bleach, and detergent compositions, containing described sodium percarbonate paprticles.

EFFECT: creation of sodium percarbonate particles possessing increased long storage stability.

14 cl, 2 ex, 4 dwg

FIELD: chemistry.

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EFFECT: increasing of stability of sodium percarbonate particles in detergents and cleansers during storage.

23 cl, 4 dwg, 4 tbl

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FIELD: technological process.

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6 cl, 1 dwg, 4 ex

FIELD: chemical industry; production of sodium percarbonate and other chemical products.

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EFFECT: the invention ensures production of sodium percarbonate with the preset range of the composition of the granules without reduction of productivity of the installation.

9 cl, 2 tbl, 4 dwg

FIELD: chemical industry; methods and devices for production of sodium percarbonate with a stabilizing coating.

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EFFECT: the invention ensures the increased stability of the granulated sodium percarbonate with the stabilizing coating.

8 cl, 2 tbl, 2 dwg

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16 cl, 4 ex, 1 dwg

FIELD: machine building.

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EFFECT: intensified process of drying, reduced dust carry over, and upgraded quality of product.

4 dwg

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EFFECT: method of granulation in fluidised layer and granulator for its implementation (versions) is described.

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FIELD: chemistry.

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6 cl, 1 dwg, 1 tbl

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EFFECT: reduced air consumption required to complete granulation process.

7 cl, 2 dwg

FIELD: technological processes.

SUBSTANCE: invention concerns granulation method in fluidised layer for various substances, such as carbamide, ammonium nitrate, ammonium chloride and similar substances viable to granulation. Particularly invention concerns method of granulation in fluidised layer with temperature adjusted by hot air feed, and to granulation plant for implementation of the method. During granulation of a certain substance in fluidised layer at adjustable temperature, finished hot granules are selected from fluidised granulation layer and cooled down in fluidised cooling layer continuously formed and sustained by fluidising air flow. At least a part of fluidising air leaving cooling fluidised layer of finished granules is fed to fluidised granulation layer. Cooling and granulation fluidised layers are positioned in sequence against air flow passing through them. Granulation plant used in the described method includes self-carrying construction with partition serving as support for fluidised granulation layer. Under the partition a step away from it, a base-forming sheet serving as support for fluidised cooling layer is located. Fluidised granulation and cooling layers interface over a perforated, grid, mesh or other gas-permeable partition. Finished granules are poured from fluidised granulation layer into fluidised cooling layer over transition stack. Devices of fluidised air feed and distribution in internal cavity of self-carrying construction are located under base-forming sheet.

EFFECT: reduced total energy expenditure required to maintain fluidised layer temperature at specified level sufficient for optimal granulation process finish.

10 cl, 2 dwg

FIELD: chemistry.

SUBSTANCE: application contains the description of method of granulating in fluidised bed and obtaining the final granules of certain substance in the so called vertically growing granulating fluidised bed which is formed and maintained by the appropriate flow of fluidising air from which the final granules are poured into the collector under excess pressure and then unloaded from it.

EFFECT: simplification and cost reduction of maintenance of unloading final granules from collector; secure preparation and preservation of monodisperse final granules of specified size.

7 cl, 3 dwg

FIELD: granulating engineering.

SUBSTANCE: device comprises vertical cylindrical housing, gas-distributing grate, vertical gas-supplying branch pipe coaxially secured inside it, tangential gas-supplying branch pipe mounted in the top section of the housing, branch pipe for supplying of dispersed material, and branch pipe for discharging granules. The vertical gas-supplying branch pipe receives the nozzle for spraying pulp or melt. The top section of the housing receives the axial gas-discharging branch pipe provided with a conical funnel and deflector. The tangential gas-supplying branch pipe is connected with the branch pipe for supplying dispersed material. The plane of the exit section of the branch pipe for supplying dispersed material is perpendicular to the axis of the tangential gas-supplying branch pipe. The deflector is made of a rotation body defined by two coaxial conical surfaces, inner surface and outer surface. The device is provided with valve gates to control the process. The valve gates are mounted in the gas-supplying pipe lines.

EFFECT: enhanced efficiency.

1 dwg

FIELD: production of powdery materials.

SUBSTANCE: the invention presents an installation with a fluidized layer and with a complex spray drying and a method of production of the powdery materials dried with the help of a spray drying, whose properties can be varied purposively depending on the application. The installation contains a spraying column, a fluidized layer, a module of a spray drying, one or several of additional spraying or pulverizing nozzles for a liquid component located in a fluidized layer, a batching gear for a powder and a powder returning gear with a fan. The module of a spray drying includes a spraying system consisting of a heated doublet spraying nozzle in which a liquid) component and sputtering air are merged. The installation contains also a dynamic filter integrated in it used for clearing of the gas of from a part of a powder. The spraying column is located above the fluidized layer. The latter for giving direction of motion of the stream of a powder it is supplied with a perforation in Conidur base. The module of a spray drying is located in the spraying column above a fluidized layer. The doublet spraying nozzle is supplied with the coaxially located powder returning gear and an enveloping stream of hot air. The spraying system is made in the form of an integrated module. In the method of production of a powdery material at the first stage the following components are combined: a liquid component, a spraying gas, a powdery material and hot air. The formed powdery product falls on a fluidized later, is caught up, fluidized and transported further. At one or more stages of granulation it is pulverized with an additional liquid component, dried and transported with the fluidized layer to the powder batching gear, from which a part of the powdery material is returned in the process. The invention ensures fast removal of surface moisture, prevention of granules adhesion and production of particles of the given size.

EFFECT: the invention ensures fast removal of surface moisture, prevention of granules adhesion and production of particles of the given size.

14 cl, 2 dwg

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