Method for producing compound fertilizer by slurry mixing

Abstract

The application discloses a method for producing compound fertilizer by slurry mixing method, which comprises the following steps: 1) solid raw materials are sent into a granulator according to proportion after being weighed by metering, liquid raw materials are sent into the granulator according to proportion, and steam is introduced to carry out granulation, so as to obtain material particles; 2) the material particles are dried, cooled and screened, so as to obtain screened particles; and 3) the screened particles are sent into a coating cylinder, and anti-coagulation oil and anti-coagulation powder are added to carry out coating, so as to obtain the compound fertilizer. The method has the characteristics of reducing the use of steam, improving the balling effect, improving the production efficiency and not needing to use a tubular reactor.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of compound fertilizer production. More particularly, the present application relates to a method for producing compound fertilizer by slurry mixing method. BACKGROUND

[0002] In the process of preparing compound fertilizer, the commonly used granulation method of compound fertilizer is ammonia acid granulation method. The granulation method needs to use a tubular reactor. The use of the tubular reactor plays a good role in the production of compound fertilizer. However, the slurry formed by ammonia acid reaction has high viscosity, which is easy to cause pipe blockage or nozzle blockage, and cleaning is quite troublesome. In addition, there is a problem of large steam consumption for wetting solid raw materials with steam, and the steam is derived from the heating and evaporation of water by burning coal, which increases the energy consumption of compound fertilizer production. SUMMARY

[0003] An object of the present application is to solve at least the above problems and to provide at least the advantages to be described later.

[0004] Another object of the present application is to provide a method for producing compound fertilizer by slurry mixing method, which can reduce the use of steam, improve the balling effect, improve the production efficiency and does not need to use a tubular reactor.

[0005] In order to achieve these objects and other advantages according to the present application, a method for producing compound fertilizer by slurry mixing method is provided, which comprises the following steps:

[0006] 1) The solid raw materials are weighed and proportionally sent into a granulator, the liquid raw materials are proportionally sent into the granulator, and steam is introduced for granulation to obtain material particles; wherein the solid raw materials are ammonium chloride, monoammonium phosphate and potassium chloride, and the liquid raw materials are liquid ammonia, sulfuric acid solution and monoammonium phosphate solution;

[0007] 2) The material particles are dried, cooled and sieved to obtain sieved particles;

[0008] 3) The sieved particles are sent into a coating drum, and an anti-coagulation oil and an anti-coagulation powder are added for coating to obtain the compound fertilizer.

[0009] Preferably, in step 1), the mass ratio of ammonium chloride, monoammonium phosphate and potassium chloride is 1-5:1-5:1-5.

[0010] Preferably, the addition amount of liquid ammonia is 1-5% of the sum of the mass of the solid raw materials, the addition amount of sulfuric acid solution is 0.5-1% of the sum of the mass of the solid raw materials, and the addition amount of the monoammonium phosphate solution is 1-10% of the sum of the mass of the solid raw materials.

[0011] Preferably, the mass fraction of the sulfuric acid solution is 50-80%.

[0012] Preferably, the mass fraction of the monoammonium phosphate solution is 50-80%.

[0013] Preferably, in step 2), the material particles are dried once and twice, the temperature of the first drying is 200-260℃, the drying time is 3-5min, the temperature of the second drying is 100-160℃, and the drying time is 5-10min.

[0014] Preferably, in step 2), the particle size of the screened particles is 2.4-4.2mm; the particles with a particle size less than 2.4mm are sent to the granulator for granulation; and the particles with a particle size greater than 4.2mm are crushed and then screened.

[0015] Preferably, in step 2), after the material particles are dried, they are cooled and screened in a multifunctional tower, which comprises:

[0016] a tower body with a rectangular cross section, a feeding port A is arranged on the right side of the top of the tower body;

[0017] a fine material screening structure comprising a first screening plate and a first partition plate, the first screening plate is arranged obliquely in the tower body and below the feeding port A, a gap is arranged between the lower end of the first screening plate and the tower wall of the tower body to form a first discharge port, the first partition plate is arranged obliquely below the first screening plate, the upper end of the first partition plate is connected with the lower end of the first screening plate, a fine material discharge port is arranged on the tower wall of the tower body, the position of the fine material discharge port corresponds to the lower end of the first partition plate to discharge the fine particle material obtained by screening the first screening plate through the fine material discharge port, and the fine material discharge port is connected with the granulator through a first pipeline;

[0018] a coarse material screening structure comprising a second screening plate and a second partition plate, the second partition plate is arranged obliquely in the tower body and below the first partition plate, the upper end of the second partition plate is opposite to the position of the first discharge port, a gap is arranged between the lower end of the second partition plate and the tower wall of the tower body to form a second discharge port, the second screening plate is arranged obliquely in the tower body and below the second partition plate, the upper end of the second screening plate is opposite to the second discharge port to make the material particles discharged from the second discharge port enter the upper end of the second screening plate, a coarse material discharge port is arranged on the tower wall of the tower body, the lower end of the second screening plate is opposite to the position of the coarse material discharge port to make the coarse particle material on the second screening plate discharged from the coarse material discharge port, and the screening hole diameter of the second screening plate is greater than that of the first screening plate;

[0019] The cooling structure comprises a plurality of cooling plates, a third partition plate and a fan; the plurality of cooling plates are arranged in the tower body in a zigzag shape, and gaps are arranged between the lower ends of the cooling plates and the tower wall of the tower body to form third discharge ports, wherein the third discharge ports formed by the lower ends of the upper cooling plates are opposite to the upper ends of the lower cooling plates; the third partition plate is arranged in the tower body and below the cooling plates, the upper end of the third partition plate is opposite to the position of the third discharge port so that the material particles discharged from the third discharge port enter the third partition plate, a granulation material discharge port is arranged on the tower wall of the tower body, the lower end of the third partition plate corresponds to the granulation material discharge port to discharge the granulation material required for coating through the granulation material discharge port, and the granulation material discharge port is connected with the coating cylinder through a second pipeline; the fan comprises an air suction fan and an air supply fan, the air suction fan is arranged below the second partition plate and above the second screening plate to suck the gas in the tower body, and the air supply fan is arranged below the cooling plate and above the third partition plate.

[0020] A crushing device is arranged beside the tower body, a feeding port B of the crushing device is connected with the coarse material discharge port through a third pipeline, and a discharging port of the crushing device is connected with the feeding port A through a fourth pipeline.

[0021] Preferably, the cooling plate is provided with a ventilation hole.

[0022] Preferably, the screening aperture of the first screening plate is 2.4 mm, the screening aperture of the second screening plate is 4.2 mm, and the aperture of the ventilation hole is less than 2.4 mm.

[0023] The present application at least has the following beneficial effects:

[0024] Firstly, the solid raw material and the liquid raw material can be directly sent into the granulator for mixing and granulation, and the addition of the liquid raw material does not need to use a tubular reactor, thereby avoiding the phenomenon of pipe blockage.

[0025] Secondly, in the granulation process, the steam is used for heating and moistening the material, the present application uses the ammonium dihydrogen phosphate solution to moisten the material, thereby reducing the steam consumption and energy consumption, and the ammonium dihydrogen phosphate solution also has the effect of improving the balling effect.

[0026] Thirdly, the multifunctional tower of the present application can realize the screening, cooling and crushing of material particles. Specifically, after being dried, the material particles enter the multifunctional tower and are screened on the first screening plate for the first time to screen out material particles with a particle size smaller than the granulation requirement, i.e. fine particle material, and the fine particle material is returned to the granulator for granulation. The fine particle material is not cooled and has a high temperature, so that it will not cause the decrease of the internal temperature of the granulator when it is returned to the granulator, thereby reducing the amount of steam introduced. After the first screening, the material particles enter the second screening plate under the guide of the second partition plate to be screened, and the material particles meeting the granulation requirement, i.e. granulation material particles, are screened out. The granulation material particles are cooled in the cooling plate and then transported to the coating cylinder for coating. The screening of the second screening plate avoids the entry of coarse material particles into the cooling plate, improves the cooling efficiency of the granulation material particles, and the coarse particle material still carries a high heat after not passing through the cooling plate, so that the material particles after being crushed still carry heat and are returned to the multifunctional tower for screening, so that the fine particle material obtained by screening and crushing the coarse particle material is returned to the granulator and still carries heat, which will not cause the sharp decrease of the temperature in the granulator, thereby reducing the amount of steam introduced into the granulator.

[0027] Other advantages, objects, and features of the present application will be apparent from the following description, and will be understood by persons skilled in the art. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Structure diagram of the multifunctional tower of an embodiment of the present application;

[0029] Figure 2 Structure diagram of the granulator of the present application;

[0030] Figure 3 Cross-sectional structure diagram of the granulator of the present application;

[0031] Figure 4 Structure diagram of the multifunctional tower of another embodiment of the present application.

[0032] 1, tower body; 2, feeding port A; 3, first screening plate; 4, first partition plate; 5, first discharge port; 6, fine material discharge port; 7, second partition plate; 8, second discharge port; 9, second screening plate; 10, coarse material discharge port; 11, cooling plate; 12, third partition plate; 13, granulation material discharge port; 14, crushing device; 15, air blower; 16, air extractor; 17, frame; 18, roller; 19, supporting wheel; 20, feeding port B; 21, discharge port B; 22, driving device; 23, elastic lining; 24, sulfuric acid solution pipe; 25, monoammonium phosphate solution pipe; 26, liquid ammonia pipe; 27, steam pipe; 28, steel ball cavity; 29, steel ball; 30, spiral conveying pipe; 31, ball. DETAILED DESCRIPTION

[0033] The application will be further described in details below with reference to the drawings, so that those skilled in the art can implement the application according to the description.

[0034] It should be understood that the terms such as "have", "contain" and "include" used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0035] It should be noted that the experimental methods in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified. In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mount", "connect", "arrange" should be understood broadly, for example, it can be fixedly connected, arranged, or detachably connected, arranged, or integrally connected, arranged. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances. The orientations or positional relationships indicated by the terms "transverse", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0036] The present application provides a method for producing compound fertilizer by slurry mixing method, comprising the following steps:

[0037] 1) After the solid raw materials are weighed by metering, they are sent into the granulator according to the proportion, liquid raw materials are sent into the granulator according to the proportion, and steam is introduced for granulation to obtain material particles; wherein the solid raw materials are ammonium chloride, monoammonium phosphate and potassium chloride, and the liquid raw materials are liquid ammonia, sulfuric acid solution and monoammonium phosphate solution;

[0038] 2) The material particles are dried, cooled and sieved to obtain sieved particles;

[0039] 3) The sieved particles are sent into a coating drum, and anti-coagulation oil and anti-coagulation powder are added for coating to obtain the compound fertilizer.

[0040] In another technical solution, in step 1), the mass ratio of the ammonium chloride, monoammonium phosphate and potassium chloride is 1-5:1-5:1-5.

[0041] In another technical solution, the added amount of liquid ammonia is 1-5% of the total mass of the solid raw materials, the added amount of the sulfuric acid solution is 0.5-1% of the total mass of the solid raw materials, and the added amount of the monammonium phosphate solution is 1-10% of the total mass of the solid raw materials.

[0042] In another technical solution, the mass fraction of the sulfuric acid solution is 50-80%.

[0043] In another technical solution, the mass fraction of the monammonium phosphate solution is 50-80%.

[0044] In another technical solution, in step 2), the material particles are dried once and twice, the temperature for the first drying is 200-260°C, the drying time is 3-5 min, the temperature for the second drying is 100-160°C, and the drying time is 5-10 min.

[0045] In another technical solution, in step 2), the particle size of the screened particles is 2.4-4.2 mm, the particles with a particle size less than 2.4 mm are sent to a granulator for granulation, and the particles with a particle size greater than 4.2 mm are crushed and then screened.

[0046] In another technical solution, in step 2), after the material particles are dried, they are cooled and screened in a multifunctional tower, which comprises:

[0047] a tower body 1 with a rectangular cross section, a feeding port A2 being arranged on the right side of the tower body 1 and above;

[0048] a fine material screening structure comprising a first screening plate 3 and a first partition plate 4, the first screening plate 3 being arranged obliquely in the tower body 1 and below the feeding port A2, a gap being arranged between the lower end of the first screening plate 3 and the tower wall of the tower body 1 to form a first discharging port 5, the first partition plate 4 being arranged obliquely below the first screening plate 3, the upper end of the first partition plate 4 being connected to the lower end of the first screening plate 3, a fine material discharging port 6 being arranged on the tower wall of the tower body 1, the fine material discharging port 6 being located in correspondence with the lower end of the first partition plate 4 to discharge fine particle material screened by the first screening plate 3 through the fine material discharging port 6, and the fine material discharging port 6 being connected to a granulator through a first pipeline;

[0049] The coarse material screening structure comprises a second screening plate 9 and a second partition plate 7, the second partition plate 7 is arranged in the tower body 1 in an inclined manner and is located below the first partition plate 4, the upper end of the second partition plate 7 is opposite to the position of the first lower discharge port 5, a gap is arranged between the lower end of the second partition plate 7 and the tower wall of the tower body 1 to form a second lower discharge port 8, the second screening plate 9 is arranged in the tower body 1 in an inclined manner and is located below the second partition plate 7, the upper end of the second screening plate 9 is opposite to the second lower discharge port 8 so that the material particles discharged from the second lower discharge port 8 enter the upper end of the second screening plate 9, a coarse material discharge port is arranged on the tower wall of the tower body 1, the lower end of the second screening plate 9 is opposite to the position of the coarse material discharge port 10 so that the coarse material particles on the second screening plate 9 are discharged from the coarse material discharge port, and the screening aperture of the second screening plate 9 is larger than the screening aperture of the first screening plate 3;

[0050] The cooling structure comprises a plurality of cooling plates 11, a third partition plate 12 and a fan, the plurality of cooling plates 11 are arranged in the tower body 1 in an inclined manner and form a "Z" type structure in the tower body 1, a gap is arranged between the lower end of the cooling plate 11 and the tower wall of the tower body 1 to form a third lower discharge port, wherein the lower end of the upper cooling plate 11 forms a third lower discharge port opposite to the upper end of the lower cooling plate 11, the third partition plate 12 is arranged in the tower body 1 in an inclined manner and is located below the cooling plate 11, the upper end of the third partition plate 12 is opposite to the position of the third lower discharge port so that the material particles discharged from the third lower discharge port enter the third partition plate 12, a granulation material discharge port 13 is arranged on the tower wall of the tower body 1, the lower end of the third partition plate 12 corresponds to the granulation material discharge port 13 so that the granulation material discharge port 13 discharges the required granulation material, the granulation material discharge port 13 is connected with the coating cylinder through a second pipeline, and the fan comprises an air extractor 16 and an air blower 15, the air extractor 16 is arranged below the second partition plate 7 and above the second screening plate 9 to extract the gas in the tower body 1, and the air blower 15 is arranged below the cooling plate 11 and above the third partition plate 12.

[0051] The crushing device 14 is arranged beside the tower body 1, the feeding port B20 of the crushing device 14 is connected with the coarse material discharge port through a third pipeline, and the discharging port 21 of the crushing device 14 is connected with the feeding port A2 through a fourth pipeline.

[0052] In another technical scheme, the cooling plate 11 is provided with a ventilation hole.

[0053] In another technical scheme, the screening aperture of the first screening plate 3 is 2.4 mm, the screening aperture of the second screening plate 9 is 4.2 mm, and the aperture of the ventilation hole is less than 2.4 mm.

[0054] In another technical solution, the third partition plate 12 is provided with a screening hole with a hole diameter < 2.4 mm, and a collecting device is arranged below the third partition plate 12 to collect fine particle materials with a particle size < 2.4 mm. The fine particle materials are collected to be re-delivered to the granulator for granulation.

[0055] <Embodiment 1>

[0056] A method for producing compound fertilizer by slurry mixing method, comprising the following steps:

[0057] 1) After the solid raw materials ammonium chloride, monoammonium phosphate and potassium chloride are weighed by metering, they are sent into a granulator in proportion, and liquid raw materials liquid ammonia, sulfuric acid solution and monoammonium phosphate solution are sent into the granulator in proportion, and steam is introduced for granulation to obtain material particles; wherein the mass ratio of the ammonium chloride, monoammonium phosphate and potassium chloride is 1:1:5, the addition amount of liquid ammonia is 1% of the sum of the mass of the solid raw materials, and the addition amount of the sulfuric acid solution is 0.5% of the sum of the mass of the solid raw materials; the mass fraction of the sulfuric acid solution is 50%; the addition amount of the monoammonium phosphate solution is 1% of the sum of the mass of the solid raw materials;

[0058] 2) The material particles are dried, cooled and screened to obtain screened particles; wherein the material particles are subjected to primary drying and secondary drying, the temperature of the primary drying is 200℃, the drying time is 5 min, the temperature of the secondary drying is 100℃, and the drying time is 10 min; the particle size of the screened particles is 2.4-4.2 mm; the particles with a particle size < 2.4 mm are sent into the granulator for granulation; the particles with a particle size > 4.2 mm are crushed and then screened again;

[0059] 3) The screened particles are sent into a coating drum, and anti-oil and anti-powder are added for coating to obtain the compound fertilizer.

[0060] <Embodiment 2>

[0061] A method for producing compound fertilizer by slurry mixing method, comprising the following steps:

[0062] 1) After the solid raw materials ammonium chloride, monoammonium phosphate and potassium chloride are weighed by metering, they are sent into a granulator in proportion, and liquid raw materials liquid ammonia, sulfuric acid solution and monoammonium phosphate solution are sent into the granulator in proportion, and steam is introduced for granulation to obtain material particles; wherein the mass ratio of the ammonium chloride, monoammonium phosphate and potassium chloride is 1:1:5, the addition amount of liquid ammonia is 1% of the sum of the mass of the solid raw materials, and the addition amount of the sulfuric acid solution is 0.5% of the sum of the mass of the solid raw materials; the mass fraction of the sulfuric acid solution is 50%; the addition amount of the monoammonium phosphate solution is 1% of the sum of the mass of the solid raw materials;

[0063] 2) drying, cooling and screening the material particles to obtain screened particles; wherein the material particles are dried once at a temperature of 260°C for 3 min and twice at a temperature of 160°C for 5 min; the screened particles have a particle size of 2.4-4.2 mm; particles with a particle size of <2.4 mm are sent to a granulator for granulation; and particles with a particle size of >4.2 mm are crushed and screened;

[0064] 3) sending the screened particles to a coating drum, adding anti-oil and anti-powder to coat the particles, and obtaining the compound fertilizer.

[0065] <Example 3>

[0066] A method for producing a compound fertilizer by the slurry mixing method, comprising the following steps:

[0067] 1) solid raw materials ammonium chloride, monoammonium phosphate and potassium chloride are weighed and proportionally sent to a granulator, liquid raw materials liquid ammonia, sulfuric acid solution and monoammonium phosphate solution are proportionally sent to the granulator, and steam is introduced for granulation to obtain material particles; wherein the mass ratio of the ammonium chloride, monoammonium phosphate and potassium chloride is 1:5:1, the addition amount of the liquid ammonia is 5% of the total mass of the solid raw materials, and the addition amount of the sulfuric acid solution is 1% of the total mass of the solid raw materials; the mass fraction of the sulfuric acid solution is 80%; the mass fraction of the monoammonium phosphate solution is 80%, and the addition amount of the monoammonium phosphate solution is 5% of the total mass of the solid raw materials;

[0068] 2) drying, cooling and screening the material particles to obtain screened particles; wherein the material particles are dried once at a temperature of 230°C for 4 min and twice at a temperature of 130°C for 7 min; the screened particles have a particle size of 2.4-4.2 mm; particles with a particle size of <2.4 mm are sent to a granulator for granulation; and particles with a particle size of >4.2 mm are crushed and screened;

[0069] 3) sending the screened particles to a coating drum, adding anti-oil and anti-powder to coat the particles, and obtaining the compound fertilizer.

[0070] <Example 4>

[0071] A method for producing a compound fertilizer by the slurry mixing method, comprising the following steps:

[0072] 1) solid raw materials ammonium chloride, monoammonium phosphate, potassium chloride are weighed and sent into the granulator according to the proportion, liquid raw materials liquid ammonia, sulfuric acid solution, monoammonium phosphate solution are sent into the granulator according to the proportion, and steam is introduced to granulate to obtain material particles; wherein the mass ratio of ammonium chloride, monoammonium phosphate and potassium chloride is 1:5:1, the addition amount of liquid ammonia is 5% of the total mass of solid raw materials, the addition amount of sulfuric acid solution is 1% of the total mass of solid raw materials; the mass fraction of sulfuric acid solution is 80%; the mass fraction of monoammonium phosphate solution is 80%, and the addition amount of monoammonium phosphate solution is 5% of the total mass of solid raw materials;

[0073] 2) the material particles are dried, cooled and sieved to obtain sieved particles; wherein the material particles are dried once and twice, the temperature of the first drying is 230°C, the drying time is 4min, the temperature of the second drying is 130°C, and the drying time is 7min; the particle size of the sieved particles is 2.4-4.2mm; the particles with a particle size of <2.4mm are sent into the granulator for granulation; the particles with a particle size of >4.2mm are crushed and sieved; after drying, the material particles are cooled and sieved in a multifunctional tower, as shown in Figure 1 The multifunctional tower comprises:

[0074] a tower body 1, the cross section of which is rectangular, the right side of the tower body 1 is provided with an inlet A2;

[0075] a fine material sieving structure, which comprises a first sieving plate 3 and a first partition plate 4, the first sieving plate 3 is obliquely arranged in the tower body 1 and located below the inlet A2, a gap is arranged between the lower end of the first sieving plate 3 and the tower wall of the tower body 1 to form a first discharge port 5, the first partition plate 4 is obliquely arranged below the first sieving plate 3, the upper end of the first partition plate 4 is connected with the lower end of the first sieving plate 3, a fine material discharge port 6 is arranged on the tower wall of the tower body 1, the position of the fine material discharge port 6 corresponds to the lower end of the first partition plate 4 to discharge fine particle material sieved by the first sieving plate 3 through the fine material discharge port 6, and the fine material discharge port 6 is connected with the granulator through a first pipeline;

[0076] The coarse material screening structure comprises a second screening plate 9 and a second partition plate 7, the second partition plate 7 is arranged in the tower body 1 in an inclined manner and is located below the first partition plate 4, the upper end of the second partition plate 7 is opposite to the position of the first lower discharge port 5, a gap is arranged between the lower end of the second partition plate 7 and the tower wall of the tower body 1 to form a second lower discharge port 8, the second screening plate 9 is arranged in the tower body 1 in an inclined manner and is located below the second partition plate 7, the upper end of the second screening plate 9 is opposite to the second lower discharge port 8 so that the material particles discharged from the second lower discharge port 8 enter the upper end of the second screening plate 9, a coarse material discharge port is arranged on the tower wall of the tower body 1, the lower end of the second screening plate 9 is opposite to the position of the coarse material discharge port 10 so that the coarse material particles on the second screening plate 9 are discharged from the coarse material discharge port, and the screening aperture of the second screening plate 9 is larger than the screening aperture of the first screening plate 3;

[0077] The cooling structure comprises a plurality of cooling plates 11, a third partition plate 12 and a fan, the plurality of cooling plates 11 are arranged in the tower body 1 in an inclined manner and form a "zigzag" structure in the tower body 1, a gap is arranged between the lower end of the cooling plate 11 and the tower wall of the tower body 1 to form a third lower discharge port, wherein the lower end of the upper cooling plate 11 forms a third lower discharge port opposite to the upper end of the lower cooling plate 11, the third partition plate 12 is arranged in the tower body 1 in an inclined manner and is located below the cooling plate 11, the upper end of the third partition plate 12 is opposite to the position of the third lower discharge port so that the material particles discharged from the third lower discharge port enter the third partition plate 12, a granulation material discharge port 13 is arranged on the tower wall of the tower body 1, the lower end of the third partition plate 12 is opposite to the granulation material discharge port 13 so that the granulation material required for coating is discharged through the granulation material discharge port 13, and the granulation material discharge port 13 is connected with the coating cylinder through a second pipeline, the fan comprises an air extractor 16 and an air blower 15, the air extractor 16 is arranged below the second partition plate 7 and above the second screening plate 9 to extract the gas in the tower body 1, and the air blower 15 is arranged below the cooling plate 11 and above the third partition plate 12;

[0078] The crushing device 14 is arranged beside the tower body 1, the feeding port B20 of the crushing device 14 is connected with the coarse material discharge port through a third pipeline, and the discharging port 21 of the crushing device 14 is connected with the feeding port A2 through a fourth pipeline;

[0079] The cooling plate 11 is provided with a ventilation hole, the screening aperture of the first screening plate 3 is 2.4 mm, the screening aperture of the second screening plate 9 is 4.2 mm, and the aperture of the ventilation hole is less than 2.4 mm;

[0080] 3) The screened particles are sent into the coating cylinder, and the anti-coagulation oil and the anti-coagulation powder are added for coating to obtain the compound fertilizer.

[0081] <Example 5>

[0082] A method for producing compound fertilizer by mixing slurry includes the following steps:

[0083] 1) Solid raw materials ammonium chloride, monoammonium phosphate, and potassium chloride are weighed and fed into a granulator in proportion. Liquid raw materials liquid ammonia, sulfuric acid solution, and monoammonium phosphate solution are fed into the granulator in proportion, and steam is introduced to granulate the material to obtain granules. The mass ratio of ammonium chloride, monoammonium phosphate, and potassium chloride is 1:5:1. The amount of liquid ammonia added is 5% of the total mass of the solid raw materials, and the amount of sulfuric acid solution added is 1% of the total mass of the solid raw materials. The mass fraction of the sulfuric acid solution is 80%. The mass fraction of the monoammonium phosphate solution is 80%, and the amount of monoammonium phosphate solution added is 5% of the total mass of the solid raw materials.

[0084] 2) The material particles are dried, cooled, and sieved to obtain sieved particles; wherein the material particles undergo primary drying and secondary drying, with the primary drying temperature at 230℃ and drying time at 4 minutes, and the secondary drying temperature at 130℃ and drying time at 7 minutes; the particle size of the sieved particles is 2.4-4.2 mm; particles with a particle size <2.4 mm are fed into a granulator for granulation; particles with a particle size >4.2 mm are crushed and then sieved; after drying, the material particles are cooled and sieved in a multi-functional tower, such as... Figure 1 As shown, the multifunctional tower includes:

[0085] The tower body 1 has a rectangular cross-section, and a feed inlet A 2 is provided on the upper right side of the tower body 1;

[0086] The fine material screening structure includes a first screening plate 3 and a first partition plate 4. The first screening plate 3 is inclinedly disposed inside the tower body 1 and located below the feed inlet A2. A gap is provided between the lower end of the first screening plate 3 and the tower wall of the tower body 1 to form a first discharge port 5. The first partition plate 4 is inclinedly disposed below the first screening plate 3. The upper end of the first partition plate 4 is connected to the lower end of the first screening plate 3. A fine material discharge port 6 is provided on the tower wall of the tower body 1. The position of the fine material discharge port 6 corresponds to the lower end of the first partition plate 4 so that the fine particulate material obtained by screening by the first screening plate 3 can be discharged through the fine material discharge port 6. The fine material discharge port 6 is connected to the granulator through a first pipe.

[0087] The coarse material screening structure comprises a second screening plate 9 and a second partition plate 7, the second partition plate 7 is arranged in the tower body 1 in an inclined manner and is located below the first partition plate 4, the upper end of the second partition plate 7 is opposite to the position of the first lower discharge port 5, a gap is arranged between the lower end of the second partition plate 7 and the tower wall of the tower body 1 to form a second lower discharge port 8, the second screening plate 9 is arranged in the tower body 1 in an inclined manner and is located below the second partition plate 7, the upper end of the second screening plate 9 is opposite to the second lower discharge port 8 so that the material particles discharged from the second lower discharge port 8 enter the upper end of the second screening plate 9, the tower wall of the tower body 1 is provided with a coarse material discharge port 10, the lower end of the second screening plate 9 is opposite to the position of the coarse material discharge port 10 so that the coarse material particles on the second screening plate 9 are discharged from the coarse material discharge port, and the screening aperture of the second screening plate 9 is larger than the screening aperture of the first screening plate 3;

[0088] The cooling structure comprises a plurality of cooling plates 11, a third partition plate 12 and a fan, the plurality of cooling plates 11 are arranged in the tower body 1 in an inclined manner and form a "Z" shaped structure in the tower body 1, a gap is arranged between the lower end of the cooling plate 11 and the tower wall of the tower body 1 to form a third lower discharge port, wherein the lower end of the upper cooling plate 11 forms a third lower discharge port opposite to the upper end of the lower cooling plate 11, the third partition plate 12 is arranged in the tower body 1 in an inclined manner and is arranged below the cooling plate 11, the upper end of the third partition plate 12 is opposite to the position of the third lower discharge port so that the material particles discharged from the third lower discharge port enter the third partition plate 12, the tower wall of the tower body 1 is provided with a granulation material discharge port 13, the lower end of the third partition plate 12 corresponds to the granulation material discharge port 13 so that the granulation material required for coating is discharged through the granulation material discharge port 13, and the granulation material discharge port 13 is connected with the coating cylinder through a second pipeline, the fan comprises an air extractor 16 and an air blower 15, the air extractor 16 is arranged below the second partition plate 7 and above the second screening plate 9 to extract the gas in the tower body 1, and the air blower 15 is arranged below the cooling plate 11 and above the third partition plate 12;

[0089] The crushing device 14 is arranged beside the tower body 1, the feeding port B 20 of the crushing device 14 is connected with the coarse material discharge port through a third pipeline, and the discharging port A of the crushing device 14 is connected with the feeding port A2 through a fourth pipeline;

[0090] The cooling plate 11 is provided with a ventilation hole, the screening aperture of the first screening plate 3 is 2.4 mm, the screening aperture of the second screening plate 9 is 4.2 mm, and the aperture of the ventilation hole is less than 2.4 mm;

[0091] 3) The screened particles are sent into the coating cylinder, and the anti-coagulation oil and the anti-coagulation powder are added for coating to obtain the compound fertilizer.

[0092] In the embodiment, in order to avoid corrosion of liquid ammonia and sulfuric acid to the inside of the granulator and avoid adhesion of material particles to the lining of the granulator, the following technical details are further included, as shown in Figure 2 、 Figure 3 The granulator comprises:

[0093] A frame 17, above which a supporting wheel 19 is arranged;

[0094] A roller 18 is rotatably arranged above the supporting wheel 19, a left end of the roller 18 is provided with an inlet port B20, and a right end of the roller 18 is provided with an outlet port B21;

[0095] A driving device 22 is arranged below the roller 18 and connected with the roller 18 to drive the roller 18 to rotate;

[0096] A feeding pipe comprises a steam pipe 27, a liquid ammonia pipe 26, an ammonium phosphate solution pipe 25 and a sulfuric acid solution pipe 24, the steam pipe 27 and the liquid ammonia pipe are arranged below the roller 18 and arranged along the axial direction of the roller 18, and the ammonium phosphate solution pipe 25 and the sulfuric acid solution pipe 24 are arranged above the roller 18 and arranged along the axial direction of the roller 18;

[0097] An anti-adhesion structure comprises six elastic linings 23, a plurality of steel balls 29 and a fixing structure, the elastic linings 23 are arranged on the inner side of the roller 18, the elastic linings 23 are connected end to end, the connection between two adjacent elastic linings 23 is fixed by the fixing structure, the elastic linings 23 are in arc-shaped structure and form a closed steel ball cavity 28 with the inner wall of the roller 18, the steel balls 29 are movably filled in the steel ball cavity 28, the elastic linings 23 are made of corrosion-resistant rubber material, the cylinder wall of the roller at the steel ball cavity 28 is provided with a vent hole, when an external force acts on the elastic lining 23, the elastic lining 23 deforms, and the steel ball cavity deforms, and the outer surface of the elastic lining 23 is provided with a plurality of protrusions.

[0098] The steam pipe 27 and the liquid ammonia pipe 26 are arranged below the roller 18, and the steam pipe 27 and the liquid ammonia pipe 26 are always inserted into the material, so that the overflow steam and liquid ammonia can be fully absorbed by the material, and the utilization rate of the steam and liquid ammonia is improved; the monoammonium phosphate solution pipe 25 and the sulfuric acid solution pipe 24 are arranged above the roller 18, and the sprayed monoammonium phosphate solution and sulfuric acid solution cover the surface of the material, and with the rotation of the roller 18, the material is turned over, that is, the material on the surface which is sprayed with the monoammonium phosphate solution and the sulfuric acid solution is turned over into the bottom layer, and after the material on the surface absorbs the monoammonium phosphate solution and the sulfuric acid solution, the material is acidic, which is more conducive to the absorption of liquid ammonia after being turned over to the bottom layer, and the utilization rate of the liquid ammonia is improved; the elastic lining 23 is arranged on the inner side of the roller 18, which avoids the corrosion of liquid ammonia and sulfuric acid to the roller 18, and prolongs the service life of the roller 18; in addition, with the rotation of the roller 18, the material particles and the steel ball 29 form extrusion to the elastic lining 23, so that the elastic lining 23 is deformed, that is, when the elastic lining 23 is at the bottom of the roller 18, the material particles extrude the elastic lining 23, and the elastic lining 23 is deformed to be recessed to the steel ball cavity 28, and with the rotation of the roller 18, when the elastic lining 23 rotates to the top end of the roller 18, the steel ball 29 extrudes the elastic lining 23 to the inside of the roller 18 to assist the elastic lining 23 to recover the deformation, and the repeated deformation can effectively prevent the material from being bonded on the elastic lining; the protrusions on the elastic lining 23 effectively prevent the material particles from caking.

[0099] <Embodiment 6>

[0100] In order to reduce equipment cost, improve crushing efficiency and improve production continuity, the difference between this embodiment and embodiment 5 is that:

[0101] The crushing device directly uses a spiral conveying pipe crushing device, such as Figure 4As shown, the spiral conveying pipe crushing device comprises a spiral conveying pipe 30 and a ball 31, one end of the spiral conveying pipe 30 is connected with the coarse material discharge port through a third pipeline, the other end of the spiral conveying pipe 30 is communicated with the feeding port A, wherein the ball 31 is thrown into the spiral conveying pipe 30, the diameter of the ball 31 is greater than 4.2 mm to prevent the ball 31 from passing through the screening hole of the second screening plate. During operation, the internal spiral mechanism of the spiral conveying pipe 30 rotates continuously, pushing the coarse material and the ball 31 to move continuously, and the continuous interaction of the ball 31, the coarse material, the spiral mechanism and the inner wall promotes the coarse material to be broken into fine material, and the ball 31 is again communicated with the feeding port A and enters the multifunctional tower. After the ball 31 enters the multifunctional tower, it falls on the first screening plate to form a bounce on the first screening plate, and it can also form a bounce on the second screening plate when it falls on the second screening plate. The bounce can make the material adhering to the screening plate or blocked in the screening hole fall off, and the cleaning and anti-blocking effect is good. And the ball 31 can continuously act on the material during the rolling process, and the large particle material is broken again. The ball 31 can be selected from metal ball 31, hard plastic ball 31 or soft rubber ball, etc. The diameter of the ball 31 is preferably 8.4 mm, which is twice the particle size of the screening particles. In this way, the ball 31 with a diameter of 8.4 mm can avoid excessive crushing of the material, so that the particle size of the crushed material is mostly in the range of 2.4-4.2 mm. The ball 31 rolls from the second screening plate and then is discharged from the coarse material discharge port to enter the spiral conveying pipe 30 again. The ball 31 circulates in this way, which can effectively improve the continuity of production.

[0102] <Comparative Test>

[0103] Comparative Example 1

[0104] The preparation method of Example 3 is adopted, and the difference from Example 3 is that liquid ammonia and sulfuric acid are sent into the granulator through the tubular reactor, and no ammonium phosphate solution is sent.

[0105] Comparative Example 2

[0106] The preparation method of Example 3 is adopted, and the difference from Example 3 is that no ammonium phosphate solution is sent.

[0107] Comparative Example 3

[0108] The preparation method of Example 5 is adopted, and the difference from Example 5 is that a traditional granulator is used.

[0109] <Test One>

[0110] The performance of the compound fertilizer prepared by Comparative Example 1, Example 3, Example 4 and Example 5 is compared from the total nutrient fluctuation of the finished product, the granulation rate, the particle strength of the finished product and the production efficiency, and the results are shown in Table 1.

[0111] Table 1

[0112]

[0113] From the results of Table 1, the results of Example 3 and Comparative Example 1 show that the preparation method of Example 3 has little effect on the nutrient fluctuation range of the compound fertilizer and the strength of the finished product particles, but the granulation rate and production efficiency are greatly improved; the results of Example 3, Example 4 and Example 5 show that the use of the multifunctional tower and the granulator of the application has little effect on the total nutrient fluctuation range of the finished product, the granulation rate and the strength of the finished product particles, and the use of the granulator of the application also has a certain improvement effect on the production efficiency.

[0114] Test Two

[0115] From the amount of steam consumed per ton of compound fertilizer produced, the steam consumption and the granulation rate of Comparative Example 2, Example 3 and Example 4 are compared, and the results are shown in Table 2.

[0116] Table 2

[0117] Steam quantity (m 3 )]]> Granulation rate (%) Comparative Example 2 15.6 80.3 Example 3 11.5 86.8 Example 4 9.8 86.5

[0118] From the results of Table 2, the results of Comparative Example 2 and Example 3 show that increasing the monammonium phosphate solution in the liquid raw material reduces the steam input and improves the granulation rate; the results of Example 3 and Example 4 show that the multifunctional tower of the application can reduce the steam input.

[0119] Test Three

[0120] 150 tons of compound fertilizer are produced by the method of Example 5 and Comparative Example 3, and after the production is completed, the adhesion of the material to the inner wall of the drum 18 is observed. The results show that when the compound fertilizer is produced by the method of Comparative Example 3, most of the inner wall of the drum 18 is adhered with material, and the adhesion thickness of the material in some local places reaches 3-5 cm; when the compound fertilizer is produced by the method of Example 5, the elastic lining is not adhered with material, and the connecting part between the elastic linings is adhered with material, and the adhesion thickness is not more than 2 cm.

[0121] Although the embodiments of the application have been disclosed as above, they are not limited to the use listed in the specification and embodiments, and can be fully applied to various fields suitable for the application, and additional modifications can be easily realized by those skilled in the art, therefore the application is not limited to specific details and the figures shown and described herein, without departing from the general concept defined by the claims and the equivalent scope.

Claims

1. A method for producing compound fertilizer by mixing slurry, characterized in that, Includes the following steps: 1) Solid raw materials are weighed and fed into a granulator in proportion. Liquid raw materials are then fed into the granulator in proportion, and steam is introduced for granulation to obtain material particles. The solid raw materials are ammonium chloride, monoammonium phosphate, and potassium chloride; the liquid raw materials are liquid ammonia, sulfuric acid solution, and monoammonium phosphate solution. The mass ratio of ammonium chloride, monoammonium phosphate, and potassium chloride is 1-5:1-5:1-5. The amount of liquid ammonia added is 1-5% of the total mass of the solid raw materials; the amount of sulfuric acid solution added is 0.5-1% of the total mass of the solid raw materials; the amount of monoammonium phosphate solution added is 1-10% of the total mass of the solid raw materials; the mass fraction of the sulfuric acid solution is 50-80%; the mass fraction of the monoammonium phosphate solution is 50-80%. The granulator includes: The frame has rollers on top; A roller is rotatably mounted above the support roller. The left end of the roller has a feed inlet B, and the right end of the roller has a discharge outlet B. A drive device is disposed below the roller and connected to the roller to drive the roller to rotate; The feed pipe includes a steam pipe, a liquid ammonia pipe, a monoammonium phosphate solution pipe, and a sulfuric acid solution pipe. The steam pipe and the liquid ammonia pipe are located below the drum and are arranged along the axial direction of the drum. The monoammonium phosphate solution pipe and the sulfuric acid solution pipe are located above the drum and are arranged along the axial direction of the drum. The anti-adhesion structure includes six elastic inner linings, several steel balls, and a fixing structure. The elastic inner linings are disposed on the inner side of the roller, and the multiple elastic inner linings are connected end to end. The connection between two adjacent elastic inner linings is fixed by the fixing structure. The elastic inner linings are arc-shaped and form a sealed steel ball cavity with the inner wall of the roller. The steel balls move and fill the steel ball cavity. The elastic inner linings are made of corrosion-resistant rubber material. Ventilation holes are provided on the roller wall at the steel ball cavity. When an external force is applied to the elastic inner linings, the elastic inner linings deform, causing the steel ball cavity to undergo compression deformation. Several protrusions are provided on the outer surface of the elastic inner linings. 2) After drying the material particles, cool and screen them to obtain screened particles; After drying, the material particles are cooled and screened in a multifunctional tower, which includes: The tower body has a rectangular cross-section, and a feed inlet A is provided on the upper right side of the tower body. A fine material screening structure includes a first screening plate and a first partition plate. The first screening plate is inclinedly disposed inside the tower body and located below the feed inlet A. A gap is provided between the lower end of the first screening plate and the tower wall of the tower body to form a first discharge port. The first partition plate is inclinedly disposed below the first screening plate, and the upper end of the first partition plate is connected to the lower end of the first screening plate. A fine material discharge port is provided on the tower wall of the tower body. The fine material discharge port is positioned opposite the lower end of the first partition plate to discharge the fine particulate material obtained by screening by the first screening plate through the fine material discharge port. The fine material discharge port is connected to a granulator through a first pipe. A coarse material screening structure includes a second screening plate and a second partition plate. The second partition plate is inclinedly disposed within the tower body and located below the first partition plate. The upper end of the second partition plate is opposite to the first discharge port. A gap is provided between the lower end of the second partition plate and the tower wall of the tower body to form a second discharge port. The second screening plate is inclinedly disposed within the tower body and located below the second partition plate. The upper end of the second screening plate is opposite to the second discharge port so that the material particles discharged from the second discharge port enter the upper end of the second screening plate. A coarse material discharge port is provided on the tower wall of the tower body. The lower end of the second screening plate is opposite to the coarse material discharge port so that the coarse particles on the second screening plate are discharged from the coarse material discharge port. The screening aperture of the second screening plate is larger than that of the first screening plate. The cooling structure includes multiple cooling plates, a third partition plate, and a fan. The multiple cooling plates are inclinedly arranged within the tower body in a zigzag pattern. A gap is formed between the lower end of each cooling plate and the tower wall to form a third discharge port, wherein the third discharge port formed by the lower end of the upper cooling plate is opposite to the upper end of the lower cooling plate. The third partition plate is inclinedly arranged within the tower body and below the cooling plates. The upper end of the third partition plate is opposite to the third discharge port to allow the material discharged from the third discharge port to pass through. The granules enter the third partition plate. The tower wall is provided with a granulation material discharge port. The lower end of the third partition plate is opposite to the granulation material discharge port so that the granules required for coating can be discharged through the granulation material discharge port. The granulation material discharge port is connected to the coating cylinder through a second pipe. The fan includes an exhaust fan and a blower. The exhaust fan is located below the second partition plate and above the second screening plate to extract the gas in the tower. The blower is located below the cooling plate and above the third partition plate to introduce gas into the tower. A crushing device is installed next to the tower body. The feed inlet B of the crushing device is connected to the coarse material discharge port through a third pipe, and the discharge port of the crushing device is connected to the feed inlet A through a fourth pipe. The crushing device directly uses a spiral conveyor crushing device, which includes a spiral conveyor and a ball. One end of the spiral conveyor is connected to the coarse material discharge port through a third pipe, and the other end of the spiral conveyor is connected to the feed port A. The ball is placed in the spiral conveyor and the diameter of the ball is greater than 4.2 mm to prevent the ball from passing through the screening holes of the second screening plate. During operation, the spiral mechanism inside the spiral conveyor rotates continuously, pushing the coarse material and the ball to continuously tumble. The continuous interaction between the ball, coarse material, spiral mechanism and inner wall causes the coarse material to be crushed into fine material. The fine material, together with the ball, is then fed into the multi-functional tower through the feed port A. 3) The screened particles are fed into a coating cylinder, and anti-caking oil and anti-caking powder are added for coating to obtain the compound fertilizer.

2. The method for producing compound fertilizer by mixing slurry according to claim 1, characterized in that, In step 2), the material particles are dried once and twice. The temperature of the first drying is 200-260℃ and the drying time is 3-5 minutes. The temperature of the second drying is 100-160℃ and the drying time is 5-10 minutes.

3. The method for producing compound fertilizer by mixing slurry according to claim 1, characterized in that, In step 2), the particle size of the screened particles is 2.4-4.2 mm; material particles with a particle size <2.4 mm are fed into the granulator for granulation; material particles with a particle size >4.2 mm are crushed and then screened.

4. The method for producing compound fertilizer by mixing slurry according to claim 1, characterized in that, The cooling plate is provided with ventilation holes.

5. The method for producing compound fertilizer by mixing slurry according to claim 4, characterized in that, The first screening plate has a screening aperture of 2.4 mm, the second screening plate has a screening aperture of 4.2 mm, and the ventilation hole has an aperture of less than 2.4 mm.

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