Production process and system of macroelement water-soluble fertilizer

Abstract

The invention provides a macroelement water-soluble fertilizer production process and a macroelement water-soluble fertilizer production system. The system comprises a feeding mechanism, a stirring device connected with the feeding mechanism, a vacuum concentrator connected with a discharging port of the stirring device, a material distributing device connected with the discharging end of the vacuum concentrator, a curing device used for curing materials and a product processing device used for drying and smashing the cured materials. The method specifically comprises the following steps: step 1, preparing slurry; the preparation method comprises the following steps: preparing phosphoric acid and urea according to a mass ratio of P2O5 / N of 2.50: 1 and a solution temperature of 50 to obtain urea-dissolved phosphoric acid slurry; step 2, concentrating the slurry; step 3, solidifying the slurry; and 4, product treatment. According to the invention, phosphoric acid and urea are used for preparing phosphoric acid-urea slurry, phosphorus and metal impurity ions in phosphoric acid are brought into the product in a water-soluble state, so that impurity metals in phosphorus and phosphoric acid are changed into water-soluble metals at low cost, and the production cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of water-soluble fertilizer preparation, and in particular to a production process and system for a large amount of element water-soluble fertilizer. Background Art

[0002] At present, water-soluble fertilizers containing a large number of elements have been widely used in integrated water-fertilizer drip irrigation facilities. In water-scarce areas of my country, such as Xinjiang, integrated water-fertilizer facilities have been extended to field crops such as cotton, corn, and potatoes. Water-soluble fertilizers containing a large number of elements are fully water-soluble, quickly soluble, and have high nutrients and good fertilizer efficiency. They have significantly helped increase production and income, and have gradually developed into a major category of fertilizers. However, the production process of most of its products is obtained by mixing and compounding, which has the problems of high raw material costs, uneven nutrients, and agglomeration, which affects the product efficacy and farmers' experience.

[0003] The common production method of macronutrient water-soluble fertilizer is to physically mix water-soluble nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer and ammonium in a certain formula, for example, industrial ammonium nitrate is used as phosphorus element, urea is used as nitrogen element, and water-soluble potassium chloride is used as potassium element to obtain macronutrient water-soluble fertilizer. However, this kind of process for obtaining macronutrient water-soluble fertilizer has the problems of high raw material cost, uneven mixing, and agglomeration of some mixtures, which affects the use effect of the product.

[0004] In the prior art, water-soluble nitrogen fertilizer, phosphorus fertilizer, potash fertilizer, and ammonium fertilizer are physically mixed with a certain formula, for example, industrial monoammonium is used as the phosphorus element, urea is used as the nitrogen element, and water-soluble potassium chloride is used as the potassium element, and a large number of elements are mixed to obtain water-soluble fertilizer. For example, the production method of a large number of elements water-soluble fertilizer containing nitrogen and phosphorus 18-46-0 is as follows: 68% (12-56-0) water-soluble monoammonium accounts for 83%, and 46% urea accounts for 17%. The two raw materials are added to a double-axis screw machine, stirred and mixed evenly, and the product is obtained after packaging.

[0005] The preparation method in the prior art has the following disadvantages:

[0006] First, there is a high cost of raw materials. A large amount of phosphorus in water-soluble fertilizers needs to be introduced through water-soluble phosphorus products, such as crystalline monoammonium phosphate, potassium dihydrogen phosphate, water-soluble APP, etc. The unit price of these products is higher than that of insoluble phosphate fertilizer products.

[0007] Second, the nutrients are uneven. When multiple solid materials are mixed through physical stirring, there are dead zones in the mixing, and the uneven stirring leads to the problem of uneven nutrients.

[0008] Third, there is the agglomeration problem. Some raw materials are prone to agglomeration. For example, industrial monoammonium itself is prone to agglomeration. Summary of the invention

[0009] The object of the present invention is to provide a production process and system for a large amount of water-soluble fertilizer. By preparing urea phosphate slurry with phosphoric acid and urea, phosphorus and metal impurity ions in phosphoric acid are brought into the product in a water-soluble state, phosphorus and impurity metals in phosphoric acid are made water-soluble at a relatively low cost, thereby reducing the production cost.

[0010] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0011] A production process of a macro-element water-soluble fertilizer specifically comprises the following steps:

[0012] Step 1: Phosphoric acid and urea are dissolved at 50-90°C. The mass of phosphoric acid is greater than that of urea so that the whole system has excess acid, and urea-phosphoric acid slurry is prepared;

[0013] Step 2: Concentrating the prepared urea-phosphoric acid slurry and maintaining the temperature at 70-130° C.;

[0014] Step 3: Use water-soluble nitrogen fertilizer, phosphate fertilizer and potash fertilizer as masterbatch, spray and apply the concentrated urea-soluble phosphoric acid slurry on the masterbatch which is 5-10 times of its own mass, so as to achieve preliminary solidification of the slurry;

[0015] Step 4: The solidified product is air-dried, sieved and crushed.

[0016] Furthermore, the mass ratio of phosphoric acid to urea is 2.5-4.5:1.

[0017] After further optimization, the mass ratio of phosphoric acid to urea was 3:1.

[0018] Wherein, the water content of the urea-soluble phosphoric acid slurry concentrate is controlled at 1-3%.

[0019] Further optimization is performed to control the water content of the urea-soluble phosphoric acid slurry concentrate to 1.5-2.5%.

[0020] Furthermore, in step 3, the masterbatch is a water-soluble fertilizer.

[0021] Preferably, the masterbatch is nitrogen fertilizer, phosphate fertilizer or potash fertilizer.

[0022] In addition, the present invention also discloses a macro-element water-soluble fertilizer production system, a feeding mechanism, a stirring device connected to the feeding mechanism, a vacuum concentrator connected to the discharge port of the stirring device, a distribution device connected to the discharge end of the vacuum concentrator, a device for solidifying materials, and a crusher for crushing the solidified materials.

[0023] Furthermore, when the material distribution device is spraying the coating, the spraying pressure is 0.3-1MPa.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] In actual use, the present invention adopts a method of introducing water-soluble phosphorus into the product. Phosphoric acid and urea are used to prepare urea phosphate slurry, and phosphorus and metal impurity ions in phosphoric acid are introduced into the product in a water-soluble state, thereby achieving water-soluble phosphorus and impurity metals in phosphoric acid at a relatively low cost.

[0026] At the same time, a large amount of free water in the urea phosphate solution is removed by vacuum concentration, and the water solubility of the urea phosphate solution is not changed during the dehydration process. The free water in phosphoric acid is removed efficiently by evaporation concentration, which has lower manufacturing cost and is more economical than drying dehydration. In addition, the water solubility of the material is not changed during the free water treatment process.

[0027] More importantly, in this application, a large amount of water-soluble fertilizer is used as the masterbatch, which is 5 to 10 times the mass of the slurry to achieve a certain amount of water in the concentrated urea phosphate slurry, which is converted from liquid to solid. The concentrated slurry is controlled to contain 1% to 3% water-soluble fertilizer, and the free water is converted into crystal water by solidification means, and converted into products instead of evaporating it by hot air drying. The energy-consuming method is to make the product more economical and avoid the problem of material denaturation during high-temperature drying. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 It is the overall process flow chart of the present invention.

[0030] Figure 2 The figure is the overall principle diagram of the production system of the macro-element water-soluble fertilizer of the present invention.

[0031] Figure 3 It is a schematic diagram of the overall internal structure of the stirring device of the present invention.

[0032] Figure 4 For the present invention Figure 3 A partial enlarged schematic diagram in the middle.

[0033] Reference numerals:

[0034] 101 feeding mechanism, 102 stirring device, 103 vacuum concentrator, 104 distribution device, 105 curing device, 106 tank body, 107 motor, 108 rotating shaft, 109 stirring unit, 110 first mounting plate, 111 second mounting plate, 112 connecting rod, 113 spoiler, 114 curved plate, 115 crushing area, 116 crushing protrusion, 117 feeding port, 118 crusher. DETAILED DESCRIPTION

[0035] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the embodiments of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0036] In the description of the embodiments of the present invention, it should be understood that the terms "length", "vertical", "horizontal", "top", "bottom", etc. indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present invention.

[0037] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0038] In the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0039] In the embodiments of the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0040] The disclosure below provides many different embodiments or examples to implement different structures of the embodiments of the present invention. In order to simplify the disclosure of the embodiments of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the embodiments of the present invention. In addition, the embodiments of the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed.

[0041] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0042] Embodiment 1

[0043] See also Figure 1-Figure 4 The present embodiment discloses a system for producing a large amount of water-soluble fertilizer of a large amount of elements, which comprises a feeding mechanism 101, a stirring device 102 connected to the feeding mechanism 101, a vacuum concentrator 103 connected to a discharge port of the stirring device 102, a distribution device 104 connected to a discharge end of the vacuum concentrator 103, a curing device 105 for curing materials, and a product processing device for drying and crushing the cured materials.

[0044] Among them, the product processing device is a pulverizer 118 with a drying function.

[0045] In actual use, the production process of macronutrient water-soluble fertilizer includes the following steps:

[0046] Step 1: Prepare slurry;

[0047] Phosphoric acid and urea are mixed in a mass ratio of P2O5 / N=2.50:1 and a solution temperature of 50°C to obtain a urea-phosphoric acid slurry.

[0048] In step 1, the phosphoric acid is excessive, which can effectively avoid the decomposition and foaming of urea in the concentration process under the protection of acid; or too low will cause foaming in the concentration process and make it difficult to concentrate the slurry; too high will make the slurry difficult to transform into a solid phase.

[0049] In actual use, in step 1, a strong stirrer is used, and a defoaming operation is performed during the stirring process.

[0050] Step 2: Concentrating the slurry;

[0051] The urea phosphate solution is concentrated by a vacuum concentrator 103 to obtain a concentrated slurry with a water content of 1%-3%. The slurry temperature is 70-130° C., and 70° C. is preferred in this embodiment.

[0052] In actual use, a kettle-type vacuum concentrator 103 is used to concentrate to the end point to ensure the moisture content of the concentrated slurry. If the moisture content is too high, it is difficult to solidify, and if the moisture content is too low, the cost is high. The slurry temperature is 70-130°C to avoid high temperature causing the slurry to be unable to be stored stably, and some phosphorus will turn to polymerized phosphorus, making it difficult for the slurry to transform into a solid state.

[0053] Step 3: Slurry solidification;

[0054] Using water-soluble nitrogen fertilizer, phosphate fertilizer and potash fertilizer as masterbatch, spray the concentrated slurry on the masterbatch which is 5-10 times of its own mass to achieve the initial solidification of the slurry. The liquid concentrated slurry is evenly dispersed into the solid masterbatch, and under the wrapping of the masterbatch, the crystallization and solidification are accelerated and converted into solid phase.

[0055] In this application, 5-10 times the mass of the masterbatch itself is used as a large return material to accelerate solidification; the masterbatch is a water-soluble nitrogen fertilizer, phosphate fertilizer, potash fertilizer, such as urea, potassium chloride, potassium sulfate, etc.

[0056] Step 4: Product processing;

[0057] The solidified product obtained in the third step is air-cooled and dried, sieved and crushed to obtain the required powdered macro-element water-soluble fertilizer. In actual use, the concentrated slurry has a certain temperature. The transition from liquid phase to solidification is a crystallization exothermic process. The masterbatch will have a temperature rise, and the heat is transferred away by air-cooled drying. It is required that the humidity is ≤50% and the temperature is below 40℃ of cold dry air.

[0058] When the material distribution device 104 is spraying the coating, the spraying pressure is 0.3-1 MPa.

[0059] In actual use, the generation of bubbles can be effectively reduced by using an excess of acid, but in actual use, some bubbles still exist; at the same time, when phosphoric acid and urea are stirred and dissolved, when high-speed stirring is used, the shaft 108 is subjected to greater force.

[0060] It should be noted that, in actual use, the phosphoric acid can be agricultural grade phosphoric acid or the raffinate acid which is a byproduct of the wet purification of phosphoric acid.

[0061] In the present embodiment, a stirring device 102 is also disclosed, and the stirring device 102 includes a tank body 106, a feeding funnel arranged on the side of the tank body 106, a rotating shaft 108 rotatably arranged inside the tank body 106, and a motor 107 installed on the tank body 106 and connected to the rotating shaft 108; a stirring unit 109 is arranged on the rotating shaft 108, and the stirring unit 109 includes a first mounting plate 110, a second mounting plate 111 and a connecting rod 112 which are hinged together end to end in sequence, the first mounting plate 110 is fixedly mounted on the rotating shaft 108, the second mounting plate 111 is slidably arranged on the rotating shaft 108, the first mounting plate 110 is located above the second mounting plate 111, and the first mounting plate 110 and the second mounting plate 111 are connected by the stirring unit 109; the connecting rod 112 located at the top is hinged to the first mounting plate 110, and the connecting rod 112 located at the bottom is hinged to the second mounting plate 111.

[0062] In the present application, there are two groups of stirring units 109 .

[0063] Furthermore, a spoiler 113 is provided at one end of one of the connecting rods 112 away from the rotating shaft 108 .

[0064] The self-adjustable stirring unit 109 can achieve the purpose of automatic adjustment according to the rotation speed of the rotating shaft 108. When the rotation speed is fast, the end of the connecting rod 112 will be close to the inner wall of the tank body 106. When the stirring speed is low, the end of the connecting rod 112 will be away from the inner wall of the tank body 106. The adjustment unit can automatically adjust the shape according to the rotation speed to meet the stirring purpose of different rotation speeds. At the same time, because the end position of the connecting rod 112 can be moved, the position of the spoiler 113 can also be moved, which can effectively improve the stirring effect.

[0065] Furthermore, in actual use, a high-pressure water spray head is arranged on the top of the tank body 106, and the high-pressure water spray head is connected to a water pump. The water pump is used to pump the solution in the tank body 106 to the high-pressure water spray head. Under the action of the water pump and the high-pressure water spray head, the solution forms a fine water line to break the foam in a high-pressure manner, which can effectively achieve the purpose of defoaming.

[0066] Furthermore, in actual use, the bottom of the tank body 106 is in an arc-shaped structure, and an arc-shaped plate 114 is provided at the bottom of the rotating shaft 108, and a crushing area 115 is formed between the arc-shaped plate 114 and the bottom of the tank body 106, and the arc-shaped plate 114 and the bottom of the tank body 106 are both provided with crushing protrusions 116 extending into the crushing area 115, and a feed port 117 is provided on the arc-shaped plate 114 near the rotating shaft 108; in this way, large particles of material can be crushed when entering the crushing area 115, thereby improving the dissolution efficiency; in the process of stirring and dissolving, large particles of material will approach the center of rotation, at which time the material will gather toward the feed port 117 and enter the crushing area 115 for crushing, and under the action of centrifugal force, the material is crushed after passing through the crushing area 115.

[0067] In actual use, variable speed dissolution is adopted in the dissolution process. When the rotating shaft 108 is at a low speed, the materials converge toward the center of the rotating shaft 108, so that more large particles enter the crushing area 115; when the rotating shaft 108 is at a high speed, the materials flow directly through the crushing area 115 under the action of centrifugal force, collide and shear with the crushing protrusions 116 to achieve rapid crushing of the materials.

[0068] Furthermore, in actual use, the setting density of the crushing protrusions 116 gradually increases in the direction away from the rotating shaft 108, so that the crushing protrusions 116 at the center position of the crushing area 115 are spaced larger, and the crushing protrusions 116 near the edge are spaced smaller, thereby achieving sufficient crushing of the material. The crushed material flows through the crushing area 115 under the action of the solution and then enters the interior of the tank body 106.

[0069] Example 2

[0070] This embodiment is basically the same as embodiment 1, except that:

[0071] Step 1: Mix phosphoric acid and urea in a mass ratio of P2O5 / N=3:1, and the solution temperature is 70℃.

[0072] Step 2: Use a vacuum concentrator 103 to concentrate the urea phosphate solution to obtain a concentrated slurry with a water content of 2% and a slurry temperature of 80°C.

[0073] Step 3: Slurry solidification;

[0074] Using water-soluble nitrogen fertilizer, phosphate fertilizer, and potash fertilizer as masterbatch, spray the concentrated slurry on the masterbatch which is 7 times its own mass to achieve the initial solidification of the slurry. Masterbatch, water-soluble nitrogen fertilizer, phosphate fertilizer, potash fertilizer, such as urea, potassium chloride, potassium sulfate, etc.

[0075] Step 4: Product processing.

[0076] Example 3

[0077] This embodiment is basically the same as embodiment 1, except that:

[0078] Step 1: Mix phosphoric acid and urea in a mass ratio of P2O5 / N=4.60:1, and the solution temperature is 90°C.

[0079] Step 2: Use a vacuum concentrator 103 to concentrate the urea phosphate solution to obtain a concentrated slurry with a water content of 3% and a slurry temperature of 130°C.

[0080] Step 3: Slurry solidification;

[0081] Using water-soluble nitrogen fertilizer, phosphate fertilizer, and potash fertilizer as masterbatch, spray the concentrated slurry on the masterbatch which is 10 times its own mass to achieve the initial solidification of the slurry. Masterbatch, water-soluble nitrogen fertilizer, phosphate fertilizer, potash fertilizer, such as urea, potassium chloride, potassium sulfate, etc.

[0082] Step 4: Product processing.

[0083] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A process for producing a large amount of water-soluble fertilizer, characterized in that: The specific steps include: Step 1: Phosphoric acid and urea are dissolved, the mass of phosphoric acid is greater than the mass of urea so that the overall system has excess acid, and urea-phosphoric acid slurry is prepared; Step 2: concentrating the prepared urea-phosphoric acid slurry; Step 3: Preliminary solidification of the slurry; Step 4: Drying, screening and crushing the cured product; Wherein, in step 1, the mass ratio of phosphoric acid to urea is 2.5-4.5:

1.

2. A process for producing a large amount of water-soluble fertilizer according to claim 1, characterized in that: The mass ratio of phosphoric acid to urea is 3:

1.

3. A process for producing a large amount of water-soluble fertilizer according to claim 1, characterized in that: The water content of the urea-soluble phosphoric acid slurry concentrate is controlled at 1-3%.

4. A process for producing a large amount of water-soluble fertilizer according to claim 3, characterized in that: The water content of the urea-soluble phosphoric acid slurry concentrate is controlled at 1.5-2.5%.

5. A process for producing a large amount of water-soluble fertilizer according to any one of claims 1 to 4, characterized in that: In step 3, the masterbatch is a water-soluble fertilizer.

6. A process for producing a large amount of water-soluble fertilizer according to claim 5, characterized in that: Masterbatch nitrogen fertilizer, phosphate fertilizer or potash fertilizer.

7. A system for producing a large amount of water-soluble fertilizer, which is used to prepare a large amount of water-soluble fertilizer by using the production process for a large amount of water-soluble fertilizer according to any one of claims 1 to 6, and is characterized in that: The production system of macro-element water-soluble fertilizer includes a feeding mechanism, a stirring device connected to the feeding mechanism, a vacuum concentrator connected to the discharge port of the stirring device, a distribution device connected to the discharge end of the vacuum concentrator, a device for solidifying materials, and a product processing device for drying and crushing the solidified materials.

8. A system for producing a large amount of water-soluble fertilizer according to claim 7, characterized in that: When the material distribution device is spraying coating, the spraying pressure is 0.3-1MPa.

Images