阅读说明：本技术 一种磷铵溶液喷浆制复合肥料的方法 (Method for preparing compound fertilizer by spraying ammonium phosphate solution ) 是由 冯玉海 冯禹桥 于 2021-03-22 设计创作，主要内容包括：本发明公开了一种磷铵溶液喷浆制复合肥料的方法,包括以下步骤：1)磷铵溶液预制备；2)磷铵乳液制备；3)半成品物料的制备；4)复合肥的制备。本发明属于复合肥肥料生产方法技术领域,通过对团粒法复合肥生产工艺改进,提供了一种生产效率高、产品质量好、生产装置环保、投资小、兼容性高的一种磷铵溶液喷浆制复合肥料的方法。(The invention discloses a method for preparing a compound fertilizer by spraying ammonium phosphate solution, which comprises the following steps: 1) pre-preparing an ammonium phosphate solution; 2) preparing an ammonium phosphate emulsion; 3) preparing a semi-finished product material; 4) and (4) preparing a compound fertilizer. The invention belongs to the technical field of compound fertilizer production methods, and provides a method for preparing a compound fertilizer by spraying ammonium phosphate solution, which has the advantages of high production efficiency, good product quality, environment-friendly production device, low investment and high compatibility through improving a production process of a compound fertilizer by a granulation method.)

1. A method for preparing a compound fertilizer by spraying ammonium phosphate solution is characterized by comprising the following steps:

1) preparing an ammonium phosphate solution: synchronously adding solid ammonium phosphate accounting for 10-30% of the total weight of the raw materials and system washing liquid required by ammonium phosphate solution concentration indexes into a primary dissolving tank, heating to 60-105 ℃ through a steam regenerative coil in the tank under a stirring state, and preparing primary ammonium phosphate solution I with the concentration of 55-95%;

2) preparing an ammonium phosphate emulsion: overflowing the primary ammonium phosphate solution I obtained in the step (1) into a secondary dissolving tank; heating the primary ammonium phosphate solution I in a secondary dissolving tank at a constant temperature of 60-105 ℃, and preparing an ammonium phosphate emulsion II with the concentration of 55-95% under the action of emulsification treatment and stirring;

3) preparing a semi-finished product material: sending the ammonium phosphate emulsion II obtained in the step (2) into a slurry spray gun with an atomizing spray head through a slurry pump, spraying the ammonium phosphate emulsion II into a rotary drum granulation device in a fogdrop mode, and forming a semi-finished product material III with the water content of 2-5% under the coating and bonding and continuous rolling action of high-temperature slurry;

4) preparing a compound fertilizer: and (4) drying, screening and cooling the semi-finished product material III obtained in the step (3) to obtain a compound fertilizer product with the particle size of 2.5-4.5 mm.

2. The method for preparing the compound fertilizer by spraying the ammonium phosphate solution according to claim 1, wherein stirring devices are respectively arranged in the primary dissolving tank and the secondary dissolving tank, an emulsifying machine is arranged in the secondary dissolving tank, the stirring speed in the step 1) is 60rpm-163rpm, and the stirring speed in the step 2) is 1450rpm-2900 rpm.

3. The method for preparing the compound fertilizer by spraying the ammonium phosphate solution according to claim 1, wherein the heating method through the steam regenerative coil in the tank in the step 1) is indirect heating through saturated steam of 0.2Mpa-0.8 Mpa.

4. The method for preparing the compound fertilizer by spraying the ammonium phosphate solution according to claim 1, wherein the ammonium phosphate solution in the step 1) can be replaced by an ammonium nitrate phosphorus solution.

5. The method for preparing the compound fertilizer by spraying the ammonium phosphate solution according to claim 1, wherein the raw materials comprise the following components in percentage by weight: 10-30% of ammonium phosphate emulsion and 70-90% of solid raw materials, wherein the solid raw materials comprise the following components: urea, ammonium phosphate nitrate, ammonium chloride, ammonium sulfate, ammonium phosphate and potassium salts.

6. The method for preparing the compound fertilizer by spraying the ammonium phosphate solution according to claim 5, wherein the solid raw materials further comprise the following components in percentage by weight: 3 to 5 percent of ammonium bicarbonate.

7. The method for preparing compound fertilizer by spraying ammonium phosphate solution according to claim 1, wherein the ammonium phosphate emulsion in the step 3) is delivered by a slurry pump, atomized by a slurry spray gun and sprayed onto the solid material bed layer in the drum granulation device in the form of fog drops.

8. The method for preparing the compound fertilizer by spraying the ammonium phosphate solution according to claim 1, wherein 2 to 4 atomizing nozzles are arranged on the slurry spray gun in the step 3).

9. The method for preparing the compound fertilizer by spraying the ammonium phosphate solution according to claim 1, wherein the drying temperature in the step 4) is 100-250 ℃.

10. The method for preparing the compound fertilizer by spraying the ammonium phosphate solution according to claim 1, wherein the screening in the step 4) comprises coarse screen screening and fine screen screening, the aperture of the coarse screen is 4.75mm, and the aperture of the fine screen is 2.5 mm.

Technical Field

The invention belongs to the technical field of compound fertilizer production methods, and particularly relates to a method for preparing a compound fertilizer by spraying ammonium phosphate solution.

Background

At present, the domestic compound fertilizer production method mainly comprises a steam granulating method and a melt tower type granulating method, wherein the steam granulating method takes solid urea, ammonium nitrate (or ammonium phosphorus nitrate), ammonium chloride, ammonium sulfate, ammonium phosphate, triple superphosphate, common calcium, potassium chloride (or potassium sulfate) and the like as raw materials, the raw materials are crushed to a certain fineness, the materials are subjected to agglomeration and granulation in a rolling bed of a rotary drum granulator (or a disc granulator) through humidification and heating, and the granulated materials are dried, screened and cooled to obtain NPK compound fertilizer products, which is a granulating method widely adopted in China. The method has some defects and weaknesses, mainly solves the problems that the granulation moisture content is high, more steam and fuel power is required to be consumed, the environmental protection pressure is high, particularly the product has low particle strength, is easy to break and agglomerate, and the like, and is a technical problem which needs to be solved urgently by a steam granulation method compound fertilizer production method.

The melt tower pelletizing process includes melting solid urea, adding other solid material, such as ammonium chloride, ammonium sulfate, ammonium phosphate, potassium chloride, etc. into urine to prepare slurry, spraying the slurry with 100 m height top with differential nozzle, cooling the sprayed liquid drop along the tower to form grains, collecting the grains from the tower bottom, sieving and cooling to obtain NPK compound fertilizer product. For the tower type melt granulation process, the problems that the investment is large, the temperature of the urea melt is high, biuret is easy to generate and is harmful to plants and the like are mainly solved.

Disclosure of Invention

In order to solve the existing problems, the invention provides a method for preparing a compound fertilizer by spraying ammonium phosphate solution, which has the advantages of high production efficiency, good product quality, environment-friendly production device, low investment and high compatibility.

The technical scheme adopted by the invention is as follows: a method for preparing a compound fertilizer by spraying ammonium phosphate solution comprises the following steps:

1) preparing an ammonium phosphate solution: synchronously adding solid ammonium phosphate accounting for 10-30% of the total weight of the raw materials and system washing liquid required by ammonium phosphate solution concentration indexes into a primary dissolving tank, heating to 60-105 ℃ through a steam regenerative coil in the tank under a stirring state, and preparing primary ammonium phosphate solution I with the concentration of 55-95%;

2) preparing an ammonium phosphate emulsion: overflowing the primary ammonium phosphate solution I obtained in the step (1) into a secondary dissolving tank; heating the primary ammonium phosphate solution I in a secondary dissolving tank at a constant temperature of 60-105 ℃, and preparing an ammonium phosphate emulsion II with the concentration of 55-95% under the action of emulsification treatment and stirring;

3) preparing a semi-finished product material: sending the ammonium phosphate emulsion II obtained in the step (2) into a slurry spray gun with an atomizing spray head through a slurry pump, spraying the ammonium phosphate emulsion II into a rotary drum granulation device in a fogdrop mode, and forming a semi-finished product material III with the water content of 2-5% under the coating and bonding and continuous rolling action of high-temperature slurry;

4) preparing a compound fertilizer: and (4) drying, screening and cooling the semi-finished product material III obtained in the step (3) to obtain a compound fertilizer product with the particle size of 2.5-4.5 mm.

Further, stirring devices are respectively arranged in the first-stage dissolving tank and the second-stage dissolving tank, an emulsifying machine is arranged in the second-stage dissolving tank, the stirring speed in the step 1) is 60rpm-163rpm, and the stirring speed in the step 2) is 1450rpm-2900 rpm. .

Further, in the step 1), the heating method by the steam regenerative coil in the tank is to introduce 0.2-0.8 Mpa of saturated steam for indirect heating.

Further, the ammonium phosphate solution in step 1) may be replaced by a ammonium nitrate phosphorus solution.

Further, the raw materials comprise the following components in percentage by weight: 10-30% of ammonium phosphate emulsion and 70-90% of solid raw materials, wherein the solid raw materials comprise the following components: urea, ammonium phosphate nitrate, ammonium chloride, ammonium sulfate, ammonium phosphate and potassium salts.

Further, the solid raw material also comprises the following components in percentage by weight: 3 to 5 percent of ammonium bicarbonate.

Further, the ammonium phosphate emulsion in the step 3) is conveyed by a slurry pump, atomized by a slurry spray gun and sprayed onto a solid material bed layer in the rotary drum granulation device in a fogdrop mode.

Further, 2-4 atomizing nozzles are arranged on the slurry spray gun in the step 3).

Further, the drying temperature in the step 4) is 100-250 ℃.

Further, the screening in the step 4) comprises coarse screening and fine screening, wherein the aperture of the coarse screen is 4.75mm, and the aperture of the fine screen is 2.5 mm.

By adopting the scheme, the invention has the following beneficial effects: the method for preparing the compound fertilizer by spraying the ammonium phosphate solution utilizes the viscosity and the solubility of the high-concentration ammonium phosphate emulsion; the prior drum granulation device is utilized to change the original high-humidity low-temperature bonding granulation into high-temperature low-humidity coating crystallization granulation. The invention can effectively improve the internal and external quality of the compound fertilizer product, and the prepared product has high granule strength and round granule surface; the granulation balling rate is good, and the production efficiency of the device is high; the ammonium phosphate slurry is adopted for spraying granulation, and tail gas washing water of a granulating device can be completely recovered, so that the method has high environmental protection characteristic.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Embodiment 1, a method for preparing a compound fertilizer by spraying ammonium phosphate solution is characterized by comprising the following steps:

1) preparing an ammonium phosphate solution: synchronously adding solid ammonium phosphate accounting for 10 percent of the total weight of the raw materials and washing liquid required by the concentration of the ammonium phosphate solution into a primary dissolving tank, heating the solid ammonium phosphate to 80 ℃ through a steam heat regenerative coil pipe in the tank in a stirring state, and preparing a primary ammonium phosphate solution I with the concentration of 65 percent:

2) preparing an ammonium phosphate emulsion: overflowing the primary ammonium phosphate solution I obtained in the step (1) into a secondary dissolving tank, heating the primary ammonium phosphate solution I in the secondary dissolving tank at a constant temperature of 80 ℃, and preparing ammonium phosphate emulsion II with the concentration of 65% under the action of emulsification treatment and stirring;

3) preparing a semi-finished product material: feeding the ammonium phosphate emulsion II obtained in the step (2) into a slurry spray gun provided with 2-4 atomizing nozzles through a slurry pump, spraying the ammonium phosphate emulsion II into a solid material bed layer in a rotary drum granulation device in a fogdrop state, introducing a small amount of steam into the solid material bed layer to supplement heat required by granulation, and forming a semi-finished product material III with the water content of 2-5% under the actions of coating and bonding of high-temperature slurry and continuous rolling;

4) preparing a compound fertilizer: and (4) drying, screening and cooling the semi-finished product material III obtained in the step (3) to obtain a compound fertilizer product with the particle size of 2.5-4.5 mm.

Embodiment 2, a method for preparing a compound fertilizer by spraying ammonium phosphate solution is characterized by comprising the following steps:

1) preparing an ammonium phosphate solution: synchronously adding solid ammonium phosphate with the weight accounting for 18 percent of the total weight of the raw materials and washing liquid required by the concentration of the ammonium phosphate solution into a primary dissolving tank, heating the solid ammonium phosphate and the washing liquid to 85 ℃ through a steam heat regenerative coil pipe in the tank in a stirring state to prepare a primary ammonium phosphate solution I with the concentration of 80 percent:

2) preparing an ammonium phosphate emulsion: overflowing the primary ammonium phosphate solution I obtained in the step (1) into a secondary dissolving tank, heating the primary ammonium phosphate solution I in the secondary dissolving tank at a constant temperature of 85 ℃, and preparing an ammonium phosphate emulsion II with the concentration of 80% under the action of emulsification treatment and stirring;

3) preparing a semi-finished product material: feeding the ammonium phosphate emulsion II obtained in the step (2) into a slurry spray gun with 2-4 atomizing nozzles through a slurry pump, spraying the ammonium phosphate emulsion II into a rotary drum granulation device in a fogdrop state, adding ammonium bicarbonate accounting for 3% of the weight of solid raw materials in the compounding of the solid raw materials of the compound fertilizer according to the weight percentage, and forming a semi-finished product material III with the water content of 2-5% under the action of coating and bonding and continuous rolling of high-temperature slurry;

4) preparing a compound fertilizer: and (4) drying, screening and cooling the semi-finished product material III obtained in the step (3) to obtain a compound fertilizer product with the particle size of 2.5-4.5 mm.

Embodiment 3, a method for preparing a compound fertilizer by spraying ammonium phosphate solution is characterized by comprising the following steps:

1) preparing an ammonium phosphate solution: synchronously adding solid ammonium phosphate accounting for 26 percent of the total weight of the raw materials and washing liquid required by the concentration of the ammonium phosphate solution into a first-stage dissolving tank, heating the solid ammonium phosphate to 92 ℃ through a steam heat regenerative coil pipe in the tank in a stirring state, and preparing a primary ammonium phosphate solution I with the concentration of 90 percent:

2) preparing an ammonium phosphate emulsion: overflowing the primary ammonium phosphate solution I obtained in the step (1) into a secondary dissolving tank, heating the primary ammonium phosphate solution I in the secondary dissolving tank at a constant temperature of 92 ℃, and preparing an ammonium phosphate emulsion II with the concentration of 90% under the action of emulsification treatment and stirring;

3) preparing a semi-finished product material: feeding the ammonium phosphate emulsion II obtained in the step (2) into a slurry spray gun with 2-4 atomizing nozzles through a slurry pump, spraying the ammonium phosphate emulsion II into a rotary drum granulation device in a fogdrop state, adding ammonium bicarbonate accounting for 3% of the weight of solid raw materials in the compounding of the solid raw materials of the compound fertilizer according to the weight percentage, and forming a semi-finished product material III with the water content of 2-5% under the action of coating and bonding and continuous rolling of high-temperature slurry;

4) preparing a compound fertilizer: and (4) drying, screening and cooling the semi-finished product material III obtained in the step (3) to obtain a compound fertilizer product with the particle size of 2.5-4.5 mm.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by the present specification, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.