Method of production of granulated carbamide and granulation tower for realization of this method

FIELD: manufacture of fertilizers; equipment for production of granulated carbamide.

SUBSTANCE: proposed method of production of granulated carbamide includes spraying its melt in granulation zone at contact with cooling air flow, hardening of drops of melt in free fall, treatment of granules with modifying agent- mixture of surfactant with film-forming agent in aqueous medium in the course of free fall at temperature of from 80 to 110°C and cooling of granules thus formed. Mixture is used in the amount of 0.01-0.16% of carbamide mass in terms of dry residual. Use may be made of ionogenic and nonionogenic agents. Film-forming agent may be selected from group containing amino-formaldehyde and epoxy resins, polyvinyl acetate and animal glues. Granulation tower has hollow housing with melt sprayer in upper part and apparatus for cooling the granules in fluidized layer in lower part, as well as injectors for spraying modifying agent which are located over circumference in lower part of tower above cooling apparatus.

EFFECT: enhanced strength of granules.

3 cl, 1 dwg, 10 ex

 

The invention relates to the production of fertilizers, and in particular to methods and apparatus for obtaining granulated urea, and can be used in industrial production of urea and other fertilizers.

Fertilizers are usually obtained in the form of granules. Due to the wide use of modes of transport in bulk, consumers fertilizer requirements are such properties of granular, as strength and caking of the granules. Particularly acute is the problem of providing these properties is for fertilizers, granulated by spraying the melt into a cooling gas (air) or liquid medium. This method of granulation, also known as pillromanian, widely used in industry, particularly in the production of most produced in the world of urea and ammonium nitrate (ammonium nitrate). However, the thus obtained granules have a lower strength compared to the granules obtained by granulating with agglomeration and subsequent washing with stirring (in a fluidized bed, in rotating drums and so on).

Usually ways to obtain granulated (prilled) urea include sprinkling it melt in the zone of granulation in contact with the cooling air flow, solidification of melt drops and cooling of the way the relating granules (Horlivka D.M. and other Technology urea. -L.: Chemistry, 1981, s-198).

To improve properties, mainly prevent caking, granulated urea, obtained as described above, there are many ways of processing by applying to the surface of granules of different modifiers (Horlivka D.M. and other Technology urea-L.: Chemistry, 1981, s-204).

Known, in particular, ways of handling granular fertilizer comprising coating the surface of granules of long-chain aliphatic compounds at a temperature above the temperature of melting (DE 1227444, 07, 1966; US 3535376, 07 C 127/00, 1970; EN 2121991, 05 G 3/00, 05 With 1/02, 01 J 2/28, 1998), non-ionic and/or ionogenic surface-active substances (surfactants) at ordinary or slightly elevated temperature (GB 1201817, C 07 C 127/00, 1970; SU 474128, 05 With 1/02, 1975). As a result of processing reduces the tendency of the granules to caking, but on the strength of granules such processing is not affected.

There is also known a method of processing granulated urea, comprising coating the surface of the granules, water modifier, which is used as a mixture of surfactants (surfactant - alkyl benzene - or alkanesulfonyl sodium, alkylsulfate sodium or triethanolamine, alkylphosphate potassium or sodium) and the film-forming agent (sodium salt of carboxymetilcellulose is) in water (aqueous solution) at ordinary temperature (SU 1570255, 05 With 9/00, 1992). As a result of processing reduces the tendency of the granules to caking, and sharply reduced consumption of supplements in comparison with the use of surfactants (from 0.005 to 0.025 wt.% compared to ˜1 wt.%). Information about the effects of such processing on the strength of granules are absent.

The closest to the proposed method to the technical essence is a method of obtaining granulated urea, including preliminary introduction in its molten catalyst of the process of polycondensation of urea with formaldehyde, the splashing of the melt in the zone of granulation in contact with the cooling air flow, solidification of melt drops in free fall, the processing of the granules during their free fall urea solution in the amount of 1-3% by weight of urea at a temperature close to the melting point of urea, cooling the resulting granules (SU 530873, 05 With 9/02, 1976).

As the catalyst used, for example, concentrated sulfuric acid, which is injected into the melt of urea with careful stirring. Then, the melt is sprayed into the column, in which countercurrent cool air with such speed as to create a fluidized layer. In the upper part of the column drops of molten urea is sprayed through a nozzle urea solution. At the height of 1/3 frequent the columns on solidifying the droplets can be further spraying hot air particles of urea fertilizer. The granules obtained according to the described technology is increased by 27-35%. However, this is achieved by introducing an additional stage of the preliminary injection into the floating catalyst. In addition, working with concentrated sulfuric acid requires compliance with the precautionary measures and the use of special equipment. All this complicates the process.

Known and is closest to the proposed to the technical nature of granulation tower, comprising a hollow casing, a spray of melt in the upper part and the apparatus for cooling the granules in the fluidized bed in the lower part (Whicharray, Bee. Synthesis and application of urea-L.: Chemistry, 1970, s-339, risb).

The task proposed by the invention is to develop a simple technological design method of producing granulated urea, allowing to obtain granules with increased strength.

The technical result that can be obtained from the use of the invention is to increase the strength of the granules granulated urea.

To achieve the technical result method for obtaining granulated urea, including the sprinkling of its melt in the zone of granulation in contact with the cooling air flow, solidification of melt drops in free PA is the situation, processing of granules modifier during their free fall, cooling the resulting granules, characterized in that as a modifier, a mixture of surfactants with film-forming agent in the aqueous medium and the mixture in an amount of 0.01 to 0.16%, calculated on the dry matter, by weight of the fertilizer applied to the surface of the granules having a temperature of from 80 to 110°C.

To obtain a technical result of the proposed method is also a device for its implementation - granulation tower, comprising a hollow casing, a spray of melt in the upper part and the apparatus for cooling the granules in the fluidized bed in the lower part, characterized in that it contains nozzles for injection of a modifier, located on a circle in the lower part of the body above the apparatus to cool the pellets in a fluidized bed.

The technical result of the invention is to improve the durability of the pellets. It can be assumed that this result occurs because in the specified temperature range, is realized in the process of free fall of granules, the surface layer of the granules has a high permeability for the components of the mixture of surfactants with film-forming agent, whereupon the processing of the granules of this mixture leads to the creation of the surface layer of greater thickness and strength. The choice in in the Arvale temperature deposition is determined in each case by the size and performance of granulation tower. At temperatures less than 80°processing does not affect the durability of the pellets. When approaching the temperature of the treated granules to the melting point of urea (132° (C) processing becomes impractical, because when the selected amount of the modifier film in these conditions is not formed.

For processing granular fertilizer under the proposed method, implemented in the proposed granulation tower, in the composition of aquatic modifiers can be used a variety of, in particular, industrial surfactant - like ionic, for example, alkali or (alkyl)ammonium salts alkylsulfonyl or monoalkylated (alkoxyalkyl) esters of sulfuric acid, halogenation salts of amines, salts of tetraalkylammonium, and nonionic, for example, various ethers of oligo - and polyalkyleneglycol, as well as mixtures of different surfactants, etc. as film-forming substances can be used a variety of, in particular, industrial products, for example aminoformaldehyde resin (in particular, urea and/or melamine, epoxy resins, polyvinyl acetate (PVA), animal glue, mixtures thereof and the like Modifier used for the processing of the granules according to the invention, is introduced into the granulation tower in fairly small amounts (0.01 to 0.16% of the mass of urea in terms of dry substance).

Depending on konkretnyh conditions (design features and dimensions of granulation tower, climatic conditions etc.) nozzles for injection of water modifier can be placed directly on the device for cooling the granules, or at some distance from him.

The invention is illustrated in the accompanying drawing, which schematically shows a vertical and horizontal sections of a particular embodiment of the proposed design of granulation tower. Granulation tower includes a housing 1, a spray melt 2, the guide cone 3, the apparatus for cooling the granules in the fluidized layer 4 with an outlet chute 5, the nozzle 6 is located between the guide cone and apparatus for cooling granules (or nozzle 7 located above the guide cone), exhaust vents 8.

The invention is also illustrated by the following examples. The compositions of the mixtures used to process the pellets are given in mass percent.

EXAMPLE 1. In the granulation tower through spray 2 serves to 30 t/h of molten urea. The tower serves 400000 nm3/h of air from the environment with a temperature of 15°C and relative humidity 70%. In the fall melt droplets in an air stream, they harden and partially cooled. Through the nozzle 6 into the tower inject 480 l/h water modifier - 1%-aqueous solution of a mixture of alkylsulfate sodium and poly is enolacetate (mass ratio of ingredients in the mixture 4:1; the amount of modifier in relation to urea, calculated on the dry matter - 0,016%). The temperature of the granules in the area of location of the nozzles 95°C. the Treated granules are finally cooled to a temperature not higher than 50°in apparatus for cooling the granules in the fluidized bed 4. The strength of granules is 0,71 kg/granule (test according to GOST 2081-92). The air from the tower through the ducting 8 enters the purification system.

EXAMPLE 2. The process is carried out analogously to example 1 with the difference that the concentration of the solution is 5% (the amount of modifier in relation to the urea in the dry matter equivalent to 0.08%). The strength of granules is 0,80 kg/granule.

EXAMPLE 3. The process is carried out analogously to example 1 with the difference that the concentration of the solution is 10% (the amount of modifier in relation to the urea in the dry matter equivalent to 0.16%). The strength of granules is 0,96 kg/granule.

EXAMPLE 4. The process is carried out analogously to example 1 with the difference that the tower through nozzles 6 inject 480 l/h water modifier - 5%-aqueous solution of a mixture of oligoanilines (obtained from C7-C9alkanol and ethylene oxide in a molar ratio of 1:2) and carboxymethyl cellulose mass ratio of 1:1 (quantity modifier in relation to the urea in the dry matter equivalent to 0.08%), the temperature of which is 0° C, and the temperature of the granules in the area of location of the nozzles 80°C. the Strength of granules is 0.78 kg/granule.

EXAMPLE 5. The process is carried out analogously to example 1 with the difference that the tower through nozzles 7 inject 480 l/h water modifier - 5%-aqueous solution of a mixture of the hydrochloride octadecylamine and urea-formaldehyde resin in a mass ratio of 1:1 (quantity modifier in relation to the urea in the dry matter equivalent to 0.08%), the air temperature is 20°and the temperature of the granules in the area of location of the nozzles 110°C. the Strength of granules is 0,86 kg/granule.

EXAMPLE 6 (comparative). The process is carried out analogously to example 1 with the difference that the tower through nozzles 6 inject 480 l/h of water. The strength of granules of 0.63 kg/granule.

EXAMPLE 7 (comparative). The process is carried out analogously to example 1 with the difference that the tower does not inject water modifier. The strength of granules of 0.63 kg/granule.

EXAMPLE 8 (comparative). The process is carried out analogously to example 4 with the difference that the tower through nozzles 6 inject 480 l/h water modifier - 5%aqueous solution of carboxymethylcellulose. The strength of granules is 0.64 kg/granule.

EXAMPLE 9 (comparative). The process is carried out analogously to example 4 with the difference that the tower through nozzles 6 inject 40 l/h of water modifier - 5%aqueous solution of oligoanilines (obtained from C7-C9alkanol and ethylene oxide in a molar ratio of 1:2). The strength of granules is 0.64 kg/granule.

EXAMPLE 10 (comparative). The process is carried out analogously to example 4 with the difference that in the tower inject 480 l/h water modifier through a nozzle located in the upper part thereof. The temperature of the granules in the area of location of the nozzles 125°C. the Strength of granules is 0.65 kg/granule.

Thus, the use of the invention allows to increase the strength of granules by 15-50%.

1. A method of obtaining a granulated urea, including the sprinkling of its melt in the zone of granulation in contact with the cooling air flow, solidification of melt drops in free fall, the processing of granules modifier during their free fall, cooling the resulting granules, characterized in that as a modifier, a mixture of surfactants with film-forming agent in the aqueous medium and the mixture in an amount of 0.01 to 0.16%, calculated on the dry matter, by weight of urea applied to the surface of the granules having a temperature of from 80 to 110°C.

2. The method according to claim 1, characterized in that the film-forming substance selected from the group comprising aminoformaldehyde and epoxy resins, polyvinyl acetate and alive is fair adhesives.

3. Granulation tower, comprising a hollow casing, a spray of melt in the upper part and the apparatus for cooling the granules in the fluidized bed in the lower part, characterized in that it contains nozzles for injection of a modifier, located on a circle in the lower part of the body above the apparatus to cool the pellets in a fluidized bed.



 

Same patents:

FIELD: chemical industry; production of fertilizers.

SUBSTANCE: the invention is pertaining to the field of chemical industry, to production of fertilizers, namely to the methods of production of granular fertilizers, and in particular, to nitrogenous and complex fertilizers, and may be used at production of the granular fertilizers with the improved properties. The method of treatment of granular fertilizers provides for application on the surfaces of the fertilizer granules (for example, carbamide, ammonium nitrate, ammonium chloride, complex NPK fertilizers), having temperature from 45 up to 100°C of the mixture of the surface-active substances with the film-forming substance in the aqueous medium. For the application may be used both ionogenic and non-ionogenic surface-active substances. The film forming substance may be chosen from the group, which contains amino-formaldehyde resins and epoxide resins, polyvinylacetate and animal glues. The technical result of the application of the additives at the heightened temperature results in the fertilizers granules strength improvement.

EFFECT: the invention ensures the fertilizers granules strength improvement.

3 cl, 36 ex, 4 tbl

FIELD: continuous-operation equipment for manufacture of mineral fertilizers; evacuation of residual gases contained in melts or hot mixtures.

SUBSTANCE: proposed device is made in form of vertical reservoir of round cross section which is provided with upper cover and branch pipes for evacuation of gases, delivery of melt or hot mixture and discharge of degassed melt of hot mixture; cylinder mounted in center of reservoir has branch pipe for delivery of melt or hot mixture; upper part of cylinder is provided with cone; disk mounted inside cylinder is rigidly connected with vibration drive through rod; it is provided with holes, 0.85 to 0.95 of diameter of cylinder which are located at distance of 0.1-0.5 of disk diameter from upper edge of cylinder.

EFFECT: enhanced efficiency; possibility of complete evacuation of gases from melt or hot mixture.

3 cl, 2 dwg

FIELD: mineral fertilizers.

SUBSTANCE: waste water intended to be utilized as fertilizer is diluted with water to content of urea peroxyhydrate 0.1-1.5% for leaf-feeding of plants and to 10-50% of urea peroxyhydrate for root nutrition of plants.

EFFECT: utilized nutritive, fungicidal, and nematocidal properties of waste waters.

5 tbl

FIELD: agriculture, in particular plant production.

SUBSTANCE: method of present invention includes utilization of urea hydroperoxide as nitrogenous fertilizer with nematocide and fungicide properties. Fertilizer of present invention also is useful in plant protection against diseases and blasts, such as potato-root eelworm and gall-root eelworm.

EFFECT: increased soil microbiological activity and fertility.

8 tbl, 8 ex

The invention relates to agriculture, namely, to products on the basis of urea, which are released during the controlled period of time, and can be used for fertilizing plants and food additives for animals

The invention relates to the field of chemistry and is used to produce fertilizers

The invention relates to methods for granular compound fertilizers based on urea with HUMATE used in agriculture

FIELD: inorganic substances technology.

SUBSTANCE: invention relates to production of granulated potassium sulfate appropriate for use in chemical industry for manufacturing mineral fertilizers and in agriculture as chlorine-free potassium-containing fertilizer. Process according to invention comprises spraying binding component onto dry potassium sulfate powder while simultaneously mixing materials in granulator mixer followed by drying thus formed granules to residual moisture not exceeding 1%. As binding component, liquid potassium soap or 50% solution thereof is used on the basis of 8 g binder per 100 g potassium sulfate. Once spraying of binding component ended, dry potassium sulfate is supplied through screw feeder to support growth of granules.

EFFECT: enabled production of granulated potassium sulfate in the form of non-caked and non-dusting product with stable granulometric composition and loose density, which contains high amount of basal substance (at least 51% K2O).

2 cl, 2 tbl

FIELD: mineral fertilizers.

SUBSTANCE: invention relates to granulated mineral fertilizers containing ammonium phosphates modified by surfactants and powdering substances, which do not lose their physicochemical properties during transportation and storage. Manufacture process comprises granulation of ammonium phosphate pulp, drying of granules, sorting and selection of commercial fraction, cooling and addition of modifying supplements. The latter are added in the cooling stage into zone with bed temperature by 5-10°C exceeding temperature of cooled product. Conditioning additives utilized can be either only liquid or the same mixed with dry powdering substances.

EFFECT: improved quality of surface coverage and simplified process.

2 cl, 3 ex

The invention relates to a process of granulation of materials of different nature, in particular to the granulation of peat and tomfooleries mixtures, fertilizer, chemical and other ultra-fine powders, carbon and mineral fibers, coal dust, animal feed, clay

The invention relates to the manufacture of pellets and can be used in the manufacture of pellets from raw materials based on wood particles

The invention relates to the field of hardening of products and batch preparation, in particular to the preparation of the charge in the scheme of acceptance of metallurgical raw materials and its delivery to the smelter in the form of granules, pellets or pelletized material

The invention relates to the processing of material in the form of liquid particles in a fluidized bed, in particular to a device for processing material in the form of particles containing a binder liquid fluidized bed

The invention relates to the production of mineral fertilizers, suitable for bulk transport and storage in bulk
The invention relates to chemical technology of organic silicon compounds, and in particular to methods of solid waste synthesis organochlorosilanes, which can be used, for example, in metallurgy

FIELD: medicine, pharmacy.

SUBSTANCE: invention relates to: (a) phenothiazine or phenothiazine analogue, or its derivative (phenothiazine material) of the formula (I): in forms of granules of spherical form mainly comprising very low amount of highly dispersed particles, and to (b) a method for preparing the phenothiazine material in forms of granules exhibiting spherical form mainly. In the formula (I) values R1, R2 and R3 are given in the invention claim. The phenothiazine material has the improved capacity for treatment, fluidity and dissolving time, minimal formation of highly dispersed particles, irritation effect and enhanced sensitivity caused by such highly dispersed particles.

EFFECT: improved preparing method, improved and valuable pharmaceutical properties of material.

44 cl, 1 dwg, 1 tbl, 2 ex

Up!