Method for production of diammonium phosphate

FIELD: agriculture, fertilizers.

SUBSTANCE: claimed method includes one-step neutralization of liquid and gas ammonia in ratio of 1:(0.25-3.0) with acidic solution having molar ratio of NH3:H3PO4 = 0.5-0.7 up to molar ratio in product of NH3:H3PO4 = 1.65-1.82, followed by product granulation and drying in single apparatus and purification of exhaust gases. Claimed ratio of liquid and gas ammonia makes it possible to control granulation process and to use reaction heat for product drying. Yield of commercial fraction (namely 2-4 mm) is 90-92 %.

EFFECT: simplified one-step process with increased yield.

5 ex, 1 dwg

 

The invention relates to the production of phosphate fertilizers, and particularly to a method of producing diammonium phosphate, is widely used as fertilizer in agriculture.

A known method of producing DAP, including the neutralization of ammonia acid component containing phosphoric acid to the molar ratio of NH3:H3PO4=1,75, granulation, drying the product and clean exhaust gases. (Technology of phosphate and compound fertilizers. Under the editorship of Eventica S.D. and Brodsky A.A., M.: Chemistry, 1987, p.194). In the known method is two-stage neutralization of ammonia with phosphoric acid. As a result of neutralization in the first stage to the molar relationships NH3:H3PO4=1,35-1,40 get partially neutralized phosphate solution (slurry). The disadvantage of this method is that due to the low viscosity of the supplied slurry of ammonium phosphates in the granulation process produces a large number of small fractions, which yield marketable fractions 2÷4 mm does not exceed 70%.

A known method of producing DAP, including the neutralization of ammonia acid component containing phosphoric acid and sulphuric acid to the molar relationship of 1.75, granulation, drying, classification of the finished product, cleaning of exhaust gases (RF Patent 2122989, IPC SW 7/00 publ. 1998). The disadvantage of this method is the high energy costs and poor quality products (caking, porosity)due to two-phase process of neutralization, the combination of the second stage neutralization with stage granulation, separate drying process. Increased consumption of ammonia for neutralization leads to additional energy consumption for the recycling of ammonia in the system, and the heterogeneity of the pulp after the first stage neutralization leads to heterogeneous composition of the granulated product, which increases its porosity and caking, causes insufficient output commodity fraction 2÷4 mm

A known method of producing DAP, including the neutralization of liquid ammonia acid component containing phosphoric acid to the molar relationship of 1.7, granulation and drying of the product in the same apparatus, the exhaust gas cleaning (RF Patent 2030370, IPC SW 7/00, publ. 1995). The disadvantage of this method is that in the two-stage neutralization of ammonia are two sequential tubular reactor, resulting in neutralisation processes and granulation become hard to control, a large amount of ammonia with the exhaust gases enters the adsorption apparatus, there are large energy costs per unit of output, and the output of a commodity is racchi 2÷ 4 mm unstable and significantly reduced.

Closest to the claimed is a method of producing DAP, including the neutralization of ammonia in a tubular reactor acid solution containing phosphoric acid, granulation and drying of the product in the same apparatus, the exhaust gas cleaning (RF Patent 2026849, IPC SW 7/00, publ. 1995). The known method is characterized by the complexity of the technological process due to the necessity of processing the slurry in the autoclave after the first stage neutralization. However due to the complexity of the negotiation processes of neutralization and granulation-drying-known method does not provide high output commodity fraction 2÷4 mm, the autoclave does not provide efficient use of the heat of reaction, thereby maintaining the increased energy consumption in the process of granulation and drying.

The task of the invention to provide a granular diammonium phosphate using single-stage ammonization. The technical result of the invention is to simplify the process, reduce energy consumption, increase the yield of marketable fractions 2÷4 mm to the level of not less than 90%. While most use a heat process ammonization (neutralization).

The task and the technical result is achieved by the fact that in the method of producing diammonium phosphate, including neutralizes the Yu ammonia acidic solution, containing phosphoric acid, granulation and drying of the product in the same apparatus, the cleaning of exhaust gases, as the acid solution containing phosphoric acid, use a solution with a molar ratio of NH3:H3PO4=0,5÷0,7 neutralization with ammonia is carried out in one stage to a molar ratio of NH3:H3PO4in the product equal to 1,65÷1,82, and serves to neutralize the mixture of liquid and gaseous ammonia at a mass ratio of 1:(0.25 to÷3,00).

The new method is to neutralize the liquid and gaseous ammonia acid solution containing phosphoric acid, in a one-step process from the molar ratio of NH3:H3PO4=0,5÷0,7 in the solution to a ratio of 1.65÷1,82 in the product. The change in the ratio of liquid and gaseous ammonia from 1:0.25 to 1:3, respectively, allows you to adjust the granulation process, receiving the output of marketable fractions 2÷4 mm from 90 to 92% and to achieve complete drying of the product by the heat of reaction. Energy saving and the use of waste process low temperature heat (30÷40° (C) when the conversion of liquid ammonia in a gas.

When the reduction ratio of liquid and gaseous ammonia is less than 1:0.25 to either increase more than 1:3 granulation process becomes insensitive to changed the Yu relations, and the percentage yield of fraction 2÷4 mm reaches less than 90%, alternatively, at a ratio more than 1:3, increased loss of heat of reaction and isolation of unreacted ammonia in the gas phase, resulting in increased overhead absorption. Molar ratio of ammonia and phosphoric acid in the original acid solution and in the pulp of the product supplied to the granulation determine the ability of the process ammonization (neutralization) in one stage. The decrease in the ratio of NH3:H3PO4in acidic solution is less than 0.5, and the degree of ammonization NH3:H3PO4in the product less 1,65 leads to deterioration of the granulation process, reducing product yield, reduce its quality (increased caking, decreases the yield of marketable fractions). The increase in the ratio NH3:H3PO4in acidic solution than 0.7, and the degree of ammonization NH3:H3PO4the product is more 1,82 leads to an increase in losses of ammonia for neutralization, the increase of the energy loss on recycling of ammonia affects the particle size of the product.

As the acidic solution is used a mixture of phosphoric acid and the absorption liquid with NH3:H3PO40.5÷0,7, a mixture of phosphoric acid and the absorption liquid with the addition of sulfuric acid with NH3H 3PO40.5÷0,7. Concentrated sulfuric acid (92÷93 wt.%) may, for example, be introduced at a rate of 40÷80 kg per 1000 kg of P2O5.

The drawing shows the installation for the production of diammoniumphosphate according to the invention, illustrating the technological scheme of production.

The method of producing diammonium phosphate according to the present invention is implemented as follows: in a tubular reactor 1 is fed with liquid or gaseous ammonia at a ratio of 1:(0.25 to÷3,0), respectively, and phosphate solution from the collector 6. Flow in a tubular reactor 1 liquid and gaseous ammonia is carried out automatically by the consumption of phosphoric acid from the collector 6. The ratio of liquid and gaseous ammonia change from 1:0.25 to 1:3.0, which determines the quantity of the commodity fraction in granular product after drum granulator-dryer 2. By increasing the amount of gaseous ammonia content of the fine fraction in the product is increased, and the surface decreases. The reaction product of neutralization of the slurry of diammonium phosphate having a temperature of 147÷150°With, sprayed into a drum granulator-dryer 2 layer product and dried flue gases. As during the neutralization the large amount of heat, while the increase in the ratio of liquid and kazooba the aqueous ammonia from 1:0.9 and above, the product is dried mainly the reaction heat. The dried product is screened through a screen 3, a large fraction is crushed in the crusher 4 and together with a small fraction is returned in a drum granulator-dryer 2, and commodity faction 2÷4 mm is cooled in the cooler 5. The air with the dust of diammonium phosphate is drawn from the cooler 5 by the fan 14, purified water in the absorber 13 and is discharged into the atmosphere. Absorption liquid solution of ammonium phosphates - from collection 12 flows into the collector of the second stage of purification of gas 9 is supplied to the phosphoric acid. In the absorber 10, the gas is cleaned of the residual ammonia and fluorine and a fan 11 is discharged into the atmosphere. Excess phosphate solution from the collector 9 is applied to the collector 7 of the first stage gas cleaning. From drum granulator-dryer 2 gas with a temperature of 95÷110°enters the first absorber stage of purification of gases, in which the molar ratio of NH3:H3PO4fosforescente absorption liquid is increased to 1.1÷1,3, and excess fluid enters the reactor tank 6, which is added to the phosphoric acid with a concentration of 52% R2O5and sulfuric acid with a concentration of 92.5%. From the reactor tank 6 phosphate solution at a temperature of 80÷90°and a molar ratio of NH3:H3PO4=0,5÷,7 is fed to the tubular reactor 1 to neutralize the liquid and gaseous ammonia.

Example 1. 18,5 t/h H3PO4with a concentration of 52% P2O5mix in the collection capacity of 50 m3with 2.6 t/h of sulfuric acid with a concentration of 92.5% and 28 t/h, the absorption liquid is a phosphate solution with a molar ratio of NH3:H3PO4=1,1. The resulting mixture is phosphonacetyl solution with a molar ratio of NH3:H3PO4=0.5 V 50 t/h served in a tubular reactor, where it is neutralized liquid and gaseous ammonia in the ratio of 1:0.25 molar ratio of NH3:H3PO4=1.8V. The resulting slurry is sprayed into a drum granulator-dryer where it is dried with hot gas, is classified and it produces a 45 t/hour of finished product of the following composition: P2O5- 46,2%, N - 18,1%, the moisture of 1.8%. Output fractions 2÷4 mm is 92%. The gases are cleaned to sanitary norms - 15 mg/m3NH3.

Example 2. 20,0 t/h H3PO4with a concentration of 52% P2O5mix in the collection capacity of 50 m3with 2.6 t/h of sulfuric acid with a concentration of 92.5% and 26.5 t/h, the absorption liquid is a mixture of phosphate solution with a molar ratio of NH3:H3PO4=1,2. The mixture - phosphate solution with a molar ratio of NH3:H3PO4=0,6 50 t/h served in a tubular reactor, where it neutralize is tons of liquid and gaseous ammonia at a ratio of 1:0.9 to molar ratio of NH 3:H3PO4=1.8V. The resulting slurry is sprayed into a drum granulator-dryer where it is dried with hot gas and the heat of reaction, classified and obtained 45 t/hour of finished product of the following composition: P2O5- 46,2%, N - 18,1%, moisture is 1.7%. Output fractions 2÷4 mm is 92%. The gases are cleaned to sanitary norms - 15 mg/m3NH3.

Example 3. 21,5 t/h H3PO4with a concentration of 52% P2O5mix in the collection capacity of 50 m3with 2.6 t/h of sulfuric acid with a concentration of 92.5% and 25.0 tons/hour, the absorption liquid is a mixture of phosphate solution with a molar ratio of NH3:H3PO4=1,3. The mixture - phosphate solution with a molar ratio of NH3:H3PO4=0,7 50 t/h served in a tubular reactor, where it is neutralized liquid and gaseous ammonia at a ratio of 1:3.0-molar ratio of NH3:H3PO4=1.8V. The resulting slurry is sprayed into a drum granulator-dryer where it is dried with hot gas and the heat of reaction, classified and obtained 45 t/hour of finished product of the following composition: P2About5- 46,2%, N - 18,1%, moisture is 1.7%. Output fractions 2÷4 mm is 92%. The gases are cleaned to sanitary norms - 15 mg/m3NH3.

Example 4. 18,5 t/h H3PO4with a concentration of 52% R O5mix in the collection capacity of 50 m3with 2.6 t/h of sulfuric acid with a concentration of 92.5% and 28 t/h, the absorption liquid is a phosphate solution with a molar ratio of NH3:H3PO4=1,1. The resulting mixture is phosphonacetyl solution with a molar ratio of NH3:H3PO4=0.5 V 50 t/h served in a tubular reactor, where it is neutralized liquid and gaseous ammonia in the ratio of 1:0.25 molar ratio of NH3:H3PO4=1,65. The resulting slurry is sprayed into a drum granulator-dryer where it is dried with hot gas, is classified and it produces a 45 t/hour of finished product of the following composition: P2O5- 46,2%, N - 18,1%, the moisture of 1.8%. Output fractions 2÷4 mm is 90%. The gases are cleaned to sanitary norms - 15 mg/m3NH3.

Example 5. 21,5 t/h H3PO4with a concentration of 52% P2O5mix in the collection capacity of 50 m3with 2.6 t/h of sulfuric acid with a concentration of 92.5% and 25.0 tons/hour, the absorption liquid is a mixture of phosphate solution with a molar ratio of NH3:H3PO4=1,3. The mixture - phosphate solution with a molar ratio of NH3:H3PO4=0,7 50 t/h served in a tubular reactor, where it is neutralized liquid and gaseous ammonia at a ratio of 1:3.0-molar with the relationships NH 3:H3PO4=1,82. The resulting slurry is sprayed into a drum granulator-dryer where it is dried with hot gas and the heat of reaction, classified and obtained 45 t/hour of finished product of the following composition: P2O5- 46,2%, N - 18,1%, moisture is 1.7%. Output fractions 2÷4 mm is 91%. The gases are cleaned to sanitary norms - 15 mg/m3NH3.

Example 6 (control). 21,5 t/h H3PO4with a concentration of 52% R2O5mix in the collection capacity of 50 m3with 2.6 t/h of sulfuric acid with a concentration of 92.5% and 25.0 tons/hour, the absorption liquid is a mixture of phosphate solution with a molar ratio of NH3:H3PO4=1,3. The mixture - phosphate solution with a molar ratio of NH3:H3PO4=0,7 50 t/h served in a tubular reactor, where it is neutralized with liquid ammonia at a ratio to the molar ratio of NH3:H3PO4=1.8V. The resulting slurry is sprayed into a drum granulator-dryer where it is dried with hot gas and the heat of reaction, classified and obtained 45 t/hour of finished product of the following composition: P2O5- 46,2%, N - 18,1%, moisture is 1.7%. Output fractions 2÷4 mm is 74%. The gases are cleaned to sanitary norms - 15 mg/m3NH3.

Thus, the present invention can simplify the the technology, to reduce energy consumption and to increase the output of marketable fractions in the production of diammonium phosphate.

Owing to the above advantages, the invention can be used in the production of phosphate fertilizers.

The method of producing DAP, including the neutralization of ammonia acid solution containing phosphoric acid, granulation and drying of the product in the same apparatus, the cleaning of exhaust gases, characterized in that the acid solution containing phosphoric acid, use a solution with a molar ratio of NH3:H3PO4=0,5÷0,7, neutralization with ammonia is carried out in one stage to a molar ratio of NH3:H3PO4in the product equal to 1,65÷1,82, this serves to neutralize the mixture of liquid and gaseous ammonia at a mass ratio of 1:(0.25 to÷3,00).



 

Same patents:

FIELD: chemistry, agriculture, fertilizers.

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2 cl, 1 tbl

FIELD: fertilizers, chemical technology.

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3 ex

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FIELD: fertilizers, chemical technology.

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FIELD: industrial inorganic synthesis.

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5 cl, 1 tbl, 5 ex

FIELD: chemical industry; food industry; pharmaceutical industry; other industries; methods of the ammonium phosphates cleaning.

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EFFECT: the invention ensures the increased output and the degree of the product purity, reduction of the production process duration.

1 ex

FIELD: chemical industry; food industry; alcohol industry; methods of production ammonium of hydroorthophosphate.

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EFFECT: the invention ensures the increased output of the product.

1 ex, 1 tbl

FIELD: by-product-coking industry; trapping of ammonia from coke oven gas by a circular phosphate method.

SUBSTANCE: the invention is pertaining to the field of a by-product coke industry, in particular, to trapping of ammonia from coke oven gas by a circular phosphate method, namely, to purification of the ammonium orthophosphates solution from the tarry matters. The method of purification of the ammonium orthophosphates solution from the tarry matters provides for feeding of the solution into the apparatus, separation of the tarry matters, their removal from the upper part of the apparatuses, and removal of the purified solution from the lower part of the apparatus. Separation of the tarry matters conduct using the mounted in the apparatus nozzle made out of the coke established in the vehicle from the coke particles with the size of less than 10 mm in amount of 70-80 % from total amount at the linear speed of the solution through its section of 0.001-0.0014 m\s. The invention allows to exclude the possibility of settling of the tarry matters particles on the bottom of the apparatus and regeneration of the nozzle, to increase productivity and reliability of the process.

EFFECT: the invention ensures purification of the ammonium orthophosphates solution from the tarry matters, to increase productivity and reliability of the process.

1 ex

FIELD: agriculture; production of mineral fertilizers.

SUBSTANCE: the invention is pertaining to production of ammonium phosphates, in particular, diammonium phosphate widely used in agriculture as mineral fertilizers. The method includes neutralization of phosphoric acid by ammonia at an increased pressure, a stirring action of the produced mixture in a static mixer with its subsequent granulation and drying of the product. Neutralization is conducted in two stages: on the first of which feed 8 - 85 % of ammonia from total amount and the process is conducted under the pressure of 3.5 - 8.0 atm, and on the second stage feed the remained amount of ammonia and reduce pressure to 1.5 - 3.0 atm. At that the stirring action is carried on simultaneously with a treatment of the mixture with ultrasound with a pulse power from 100 up to 1000 W. Before granulation additionally reduce the pressure by 0.5 - 0.8 atm as compared with the pressure of the second stage of neutralization. Ultrasonic treatment additionally conduct and on the first stage of neutralization. The technical result is production of a homogenous product of improved quality, decreased power inputs and losses of ammonia in the general process.

EFFECT: the invention ensures production of a homogenous product of improved quality, decreased power inputs and losses of ammonia in the general process.

2 cl, 3 ex

FIELD: fertilizers, chemical technology.

SUBSTANCE: invention relates to a method for preparing monoammonium phosphate used broadly as a mineral fertilizer. Method involves decomposition of phosphate with a mixture of phosphoric and sulfuric acid, separation of reaction mass with isolation of the production acid, its purifying from impurities, concentrating, ammoniation to obtain phosphate pulp and the following procedures of granulation and drying. The separated production acid is concentrated and then subjected for purification from impurities and ammoniated maintaining the content of P2O5 in the concentrated acid at these stages in the range 52-56%, the content of SO3 at the range 1.5-3.2%, the residual content of solid impurities in the cleared concentrated acid 0.2-0.6% by mass, and the mole ratio NH3 : H3PO4 in the range 1.01-1.16. Regulation of the yield for required sort of monoammonium phosphate by the content of main nutrient substances and the ratio is carried out by change of the SO3 content in dilute phosphoric acid and by change of the mole ratio NH3 : H3PO4 in the ammoniation process. Invention provides enhancing content of total sum of nutrient substances in the fertilizer and enhancing strength index of granules and their homogeneity.

EFFECT: improved preparing method.

2 cl, 4 ex

FIELD: industrial inorganic synthesis.

SUBSTANCE: invention relates to production of ammonium phosphates, notably ammophos, widely used as mineral fertilizers. Process involves neutralization of phosphoric acid with ammonia at elevated pressure, stirring of resulting mixture in static mixer, and subsequent granulation and drying of product. According to invention, neutralization is carried out in two steps: in the first step, 80-85% H3PO4 of its total amount is added and process is carried out at gauge pressure 3.5-8 atm and, in the second step, the rest of acid is added and pressure is lowered to pressure 1.5-3.0 atm. Stirring is effected simultaneously with ultrasonic treatment of the mixture with pulse power from 100 to 1000 W and, before granulation, pressure is lowered by 0.5-0.8 atm relative to pressure of the second neutralization step. Ultrasonic treatment can likewise be employed in the first neutralization step.

EFFECT: improved process control to form uniform improved-quality product and reduced ammonia emission.

2 cl, 3 ex

The invention relates to a method for producing the phosphorus-containing fertilizers such as diammonium phosphate, having a stable dark color of demand in the market
The invention relates to the technology of mineral fertilizers, namely, to obtain from the map solution of ammonium phosphate, which can be used as the phosphorus-containing component is completely water-soluble nitrogen-phosphorus-or nitrogen-phosphorus-potassium fertilizers
The invention relates to methods for producing ammonium phosphates, such as monoammonium phosphate and diammonium phosphate, based on the decomposition of phosphate rock with a mixture of phosphoric and sulphuric acids to produce phosphoric acid and its further processing into fertilizer
The invention relates to a method for producing the phosphorus-containing fertilizers such as diammonium phosphate, having a stable dark color of demand in the market

FIELD: industrial inorganic synthesis.

SUBSTANCE: invention relates to production of ammonium phosphates, notably ammophos, widely used as mineral fertilizers. Process involves neutralization of phosphoric acid with ammonia at elevated pressure, stirring of resulting mixture in static mixer, and subsequent granulation and drying of product. According to invention, neutralization is carried out in two steps: in the first step, 80-85% H3PO4 of its total amount is added and process is carried out at gauge pressure 3.5-8 atm and, in the second step, the rest of acid is added and pressure is lowered to pressure 1.5-3.0 atm. Stirring is effected simultaneously with ultrasonic treatment of the mixture with pulse power from 100 to 1000 W and, before granulation, pressure is lowered by 0.5-0.8 atm relative to pressure of the second neutralization step. Ultrasonic treatment can likewise be employed in the first neutralization step.

EFFECT: improved process control to form uniform improved-quality product and reduced ammonia emission.

2 cl, 3 ex

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