JP2000256088A - Production of coated fertilizer and its apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively and stably produce a time interval elution type coated fertilizer reduced in initial suppression down to a satisfactory level on an industrial scale by disposing a dust removing device having performance of a removal rate above a specific value between a gas outlet from a coating device and a gas cooling condenser disposed in a circulation system for gas and removing the dust used for drying. SOLUTION: The performance of the dust removing device is >=95% in the removal rate of 1 to 10-micron particles and >=99.5% in the removal rate of 10 to 100-micron particles. The coated fertilizer is produced by using the device for coating the fertilizer surface with a polymer solution and reintroducing the gas used for drying discharged from the coating device into the coating device. Not only the shape of the particles of the fertilizer but the dust derived from the particles of the fertilizer exert a significant influence on the initial elution of the coated fertilizer and the dust removing device is built into the gas circulation system for solvent drying. The dust removing device is a bag filter, an electrostatic precipitator, etc. The material that exerts the significant influence on the elution is the water-soluble particles of 1 to 100 microns.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method and an apparatus for producing a coated fertilizer of good quality. More specifically, the present invention relates to a method and an apparatus suitable for producing a coated fertilizer in which elution of an initial fertilizer component is suppressed.

[0002]

2. Description of the Related Art As a method of coating a fertilizer with a polymer, for example, Japanese Patent Publication No. 54-3104 and Japanese Patent Publication No. 56-8
As described in No. 9, there is known a method in which a polymer solution is sprayed on fertilizer particles, and at the same time, a high-speed hot air flow is applied to the rolling or jetting fertilizer particles to instantaneously dry the fertilizer particles. In recent years, the requirements for the elution pattern of coated fertilizers have diversified. Conventionally, only the linear type, in which the elution rate increases almost linearly over a certain period, and the regular type, in which the initial elution rate is higher than this, Rather, the sigmoid type in which the initial dissolution rate is suppressed has been favorably used because the nutrient absorption pattern of the crop and the dissolution of the fertilizer almost coincide with each other. Methods for producing these sigmoid fertilizers are disclosed, for example, in Japanese Patent Publication No. Hei 5-29634 and Japanese Patent Application Laid-Open No. Hei 9-132493.

[0003] Further, fertilizers used for extremely concentrated fertilization and cultivation methods such as a total basal fertilization method using a nursery box include a period during which fertilizer components are not eluted after application or a period during which elution is extremely suppressed. There is a demand for a so-called timed elution type having a period in which rapid elution is performed after a certain period of time. The total amount fertilizer application method is to apply the entire amount or most of the fertilizer required during the cultivation period to the nursery box as the above-mentioned time-eluting type coated fertilizer at the start of the seedling raising, and dissolve the time-eluting type coated fertilizer. It is necessary that the elution is extremely suppressed during the seedling raising period, and the elution begun immediately after the seedling raising period is completed (after transplantation in this field). By using such a time-eluting type coated fertilizer, it is possible to quickly absorb the fertilizer required in this field without causing a concentration disorder due to the fertilizer eluted during the seedling raising period. Furthermore, the roots that have emerged from the seeds or seeds come into contact with the time-eluting type coated fertilizer as they grow, and eventually become fertilized by the roots.When the grown seedlings are transplanted to this field, the roots carry the fertilizer. To be transplanted. Therefore, it is possible to directly absorb the fertilizer from the fertilizer with which the root is in contact, and it is possible to greatly improve the absorption efficiency of the fertilizer.

[0004] However, in order to realize such a fertilization method, it is premised that the time-eluting type coated fertilizer does not cause concentration disturbance due to elution of the fertilizer during the seedling raising period of the crop. It is necessary that the dissolution rate is extremely low, and stricter dissolution control is required compared to the conventional linear or regular type dissolution pattern coated fertilizer. The basic coating composition and production method for producing these time-eluting coated fertilizers are described in JP-A-4-202078.
JP-A-4-202079 and JP-A-6-876
No. 84. Further, as preferable devices and production methods for further suppressing the dissolution rate during the initial dissolution suppression period, JP-A-10-118557 and JP-A-10-156 are known.
166 and JP-A-10-156167.

[0005] A method and an apparatus for producing a coated fertilizer are described in the above-mentioned patent gazette, but an apparatus for producing a coated fertilizer including a gas circulation system is disclosed in JP-B-56-38255.
No. 4,867,059 discloses an example including a coating device, a cyclone, a cooler, a blower, an air heater, and the like. However, with these methods alone, even if the coating composition shows a time-eluting type elution, if it is intended to produce these in large quantities, the elution rate during the initial suppression period will be at a level that is satisfactory with a thin film. It has been difficult to stably produce the reduced amount.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and an apparatus for producing a large amount and stably of a time-eluting coated fertilizer used in a total fertilizer application method for raising seedlings. In order to suppress the initial dissolution of the coated fertilizer, it is generally important to form a polymer film having a uniform thickness on the fertilizer particles. For this purpose, it is preferable to use a method in which the shape of the fertilizer particles is as round as possible with as few irregularities as possible, and the polymer is repeatedly applied at a low concentration many times.

However, there is a problem in that the shape of the fertilizer particles is limited, it is difficult to eliminate the irregularities at all, and it is necessary to sacrifice the productivity of the coated fertilizer in recoating. there were. Increasing the thickness of the coating is also an effective means of suppressing the initial elution of the coated fertilizer, but thickening the coating not only reduces the active ingredient content of the fertilizer, but also increases the cost of the coating. Must be used a lot, which is economically disadvantageous. It has been desired to develop an apparatus for stably producing a time-eluting coated fertilizer reduced to a level that can satisfy the initial control at a low cost on an industrial scale.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies on a method and an apparatus for producing a coated fertilizer which suppresses the initial elution of the coated fertilizer. It has been found that dust derived from ash has a great influence on the initial elution of the coated fertilizer, and the present invention has been completed in which a dust removal device is incorporated in a gas circulation system for solvent drying. That is, the method for producing a coated fertilizer of the present invention uses a coating device that coats the surface of the fertilizer with a polymer by spraying a solution of the polymer onto the surface of the fertilizer and drying the gas used for drying discharged from the coating device. In a method of producing a coated fertilizer by re-introducing into a coating device from a circulation system, removing 1 to 10 micron particles between a gas outlet from the coating device and a gas cooling condenser provided in the gas circulation system. A dust removing device having a performance of 95% or more and a removal rate of 10 to 100 micron particles of 99.5% or more is provided to remove gas dust used for drying.

[0009] The apparatus for producing a coated fertilizer of the present invention comprises an apparatus for coating the surface of a fertilizer with a polymer by spraying and drying a polymer solution on the surface of the fertilizer, and an apparatus for coating a gas used for drying discharged from the coating apparatus. And a gas circulating system for reintroducing the gas into the coated fertilizer, wherein a gas outlet and a gas cooling condenser provided in the gas circulating system have a 1-10 A dust removing device having a performance of removing micron particles of 95% or more and a removing efficiency of 10 to 100 micron particles of 99.5% or more is provided. The gas circulation system includes a gas circulation blower and a hot air generator. The fertilizer to be coated is cooled after being coated with the coating device, and becomes a product.

In the present invention, the gas for drying is blown by a gas circulation blower, heated by a hot air generator and enters the coating device, and the gas containing the organic solvent exiting the coating device is removed by a dust removing device. Then, the organic solvent is liquefied and separated in the cooling condenser and returned to the gas circulation blower. Air is usually used as the gas used for drying the solvent, and it is efficient to circulate the gas in consideration of preventing air pollution and reducing loss of the solvent. The coating liquid is obtained by dissolving and / or dispersing a coating material in an organic solvent in a coating liquid adjusting tank, and is sent from the adjusting tank or the intermediate tank to the coating apparatus by a liquid sending pump.

The order of these devices does not necessarily have to be in this order, but in consideration of the contamination of the device by dust and the like, the dust removing device is preferably provided immediately after the coating device. In the study of the present inventor, the dust generated from the coating apparatus during the coating operation is large at the beginning of coating, and the generation of dust decreases as the coating rate increases, and when the surface of the fertilizer is completely covered, the dust is generated. The occurrence is almost eliminated.
Therefore, dust alone generated in the coating apparatus does not significantly affect the initial elution of the fertilizer.

[0012] In a device that uses hot air for drying fertilizer in a circulating manner, if there is no dust removal device or if the efficiency is low, the circulating gas contains fine dust. Because of the trapping, accumulation and release effects of many devices and equipment in the yard, it is constantly transported into the coating equipment, so it does not fluctuate much during the coating operation, and it is always coated from the start of coating to the end of coating. It has a great effect on the initial elution of fertilizers because it is taken up in the soil. Therefore, it becomes important to efficiently collect dust in the circulating gas.

The construction of the apparatus for producing coated fertilizer of the present invention will be described in detail below. As the coating device used in the present invention, a conventionally known coating device can be used.
Specifically, a tumbling type, a fluidized bed type, a spouted bed type, or the like can be used, and a spouted bed type coating apparatus is preferable in that a coating film can be instantaneously dried. Further, those having a guide tube for a jet flow inside the spouted bed are particularly preferable.

The dust removing device used in the present invention includes:
A removing device such as a tap filter or an electric dust collector can be used. It is necessary for the dust removal performance to have a removal rate of 1 to 10 micron particles of 95% or more and a removal efficiency of 10 to 100 micron particles of 99.5% or more. Particles larger than 100 microns settle down largely in the circulation and contaminate the piping and equipment in the circulation, but very rarely return to the coating equipment. In addition, particles having a particle diameter of less than 1 micron not only generate less dust, but also have a smaller particle size and less influence than the thickness of the coating. When a dust removing device is not installed, water-soluble particles having a size of 1 to 100 microns mainly affect elution, and a device for efficiently removing these particles is preferable.

Examples of such an apparatus include a back filter and an electric dust collector as described above. A general cyclone has a low removal efficiency of particles of 10 microns or less, and a high removal efficiency of small particles such as a multicyclone has a removal efficiency of approximately 80% of particles of approximately 10 microns. In order to achieve this, it is necessary to have a smaller particle removal efficiency. In addition, a cyclone with high removal efficiency for relatively large particles,
It is preferable to use in combination with an electrostatic precipitator having a high efficiency of removing small particles. Further, as the dust removing device, a bag filter is particularly preferable in terms of simplicity of the device and high removal efficiency of particles of 1 micron or more. When a combination of a cyclone and an electrostatic precipitator and a bag filter are used, particles having a size of 100 microns or more can be removed at the same time, and there is an advantage that contamination of the apparatus is reduced.

As the operating conditions, it is preferable to operate at a temperature at which the solvent in the circulating gas does not condense.
When the solvent condenses, dust adheres to the wall surface of the device, which makes it difficult to discharge from the device. In the case of a bag filter, the pressure loss may be abnormally large. As the gas circulation blower used in the present invention, a conventionally known device can be used as long as a predetermined air blowing amount and discharge pressure are satisfied. For example, a turbofan centrifugal blower, a movable blade type rotary compressor, a roots blower, a Nash pump, and the like can be given.

The hot air generator used in the present invention includes:
As long as the gas can be heated to a predetermined temperature, a conventionally known ordinary gas heat exchanger can be used. For example, multi-tube type with fins, gas outside the tube,
A heat exchanger of a type in which pressurized steam flows through the pipe can be used. As the cooling condenser used in the present invention, a conventionally known ordinary cooling condenser may be used as long as it has a performance capable of cooling a gas containing an organic solvent to a predetermined temperature. Can be. For example, it is possible to use a finned multi-tubular heat exchanger similar to the hot air generator, in which cooling water flows through the pipes.

The coating liquid adjusting tank used in the present invention needs to be a device capable of dissolving a polymer in a solvent and dispersing an inorganic powder in the solvent, and a stirring device and a heating device are required. A fitted tank is preferred. As the liquid sending pump used in the present invention, a conventionally known ordinary sending pump can be used as long as it has a sending pressure capable of spraying a liquid containing a polymer from a spray nozzle in a coating apparatus and a predetermined sending ability. A liquid pump can be used. For example, a plunger pump, a gear pump, a screw pump, and the like can be used.

In the present invention, the order in which the gas for circulation flows in these devices is such that the gas heated by the hot air generator enters the coating device, and the gas containing the solvent exiting the coating device enters the cooling condenser. The order is essential, and the gas circulation blower and the dust removal device are installed somewhere between these devices. Dust generated by the coating equipment contaminates other equipment,
In order to prevent the cooling and heating efficiency from being reduced, the dust removing device is preferably installed immediately after the coating device. Further, in order to reduce the corrosion of the blower by the solvent and the corrosion of the blower due to the high temperature, it is preferable to install the gas circulation blower between the cooling condenser and the hot air generator. For these reasons, in a particularly preferred order, the gas heated by the hot-air generator immediately enters the coating device, the gas containing the solvent leaving the coating device immediately enters the dust removal device, and then the cooling condensing device. , And pressurized by the gas circulation blower to return to the hot air generator.

Further, in order to produce a fertilizer in which the initial elution of the coated fertilizer is stably reduced, the product coated fertilizer and the crushed fertilizer particles, large dust, and dust generated in the coating after the coating device of the above device. It is preferable to provide a sieve or the like for separating a large lump of fertilizer or the like. As such a sieve or the like, any type may be used as long as it does not damage the coating, but a continuous vibrating sieve is usually used. Also, the upper opening of the continuous vibrating sieve is preferably slightly larger than the opening of the fertilizer before coating,
Further, it is preferable that the size of the lower opening is the same as that of the fertilizer before coating. The reason for making the upper opening slightly larger is to take into account the thickening of fertilizer particles due to coating.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an example of a coated fertilizer manufacturing apparatus of the present invention, an example of a method of manufacturing a coated fertilizer by the manufacturing apparatus, and evaluation of the obtained coated fertilizer will be described. However, the present invention is not limited to the following embodiments.

Example 1 1) Apparatus for producing coated fertilizer FIG. 1 shows an apparatus for producing coated fertilizer of the present invention. In FIG. 1, reference numeral 1 denotes a jet tower having a tower diameter of 400 mm and a height of 3 m, which has an inlet for raw manure and an outlet for coated material. Reference numeral 2 denotes a bag filter, which contains three filters having an inner diameter of 200 mm, a length of 2 m, and a micron removing capability of 99.5%. 3 is a fin tube type cooling condenser having an effective heat transfer area of 56 square meters. 4 is 600N cubic m / hr,
It is a roots-type blower with a blowing capacity of 0.35 atm.
Reference numeral 5 denotes a fin tube type hot air generator having an effective heat transfer area of 7.5 square meters. 6 is 800mm inside diameter, 700mm height
This is a coating liquid adjustment tank of a stirrer, which is equipped with a stirrer, a steam jacket for heating, and a temperature controller.
Reference numeral 7 denotes a 2.5 L / min plunger type liquid feed pump. Reference numeral 8 denotes a spray nozzle, 9 denotes a guide tube having a diameter of 120 mm, and 10 denotes a vibrating sieve. In FIG. 1, cw is cooling water, sol is a condensed organic solvent, st is steam, dr
Indicates condensed water.

2) Production method of coated fertilizer (NP fertilizer for growing all-vegetable basal cell seedlings) Using the above-mentioned apparatus for producing coated fertilizer, coated granular fertilizer was produced by the following operation. Parkroll ethylene 414k
g was put into a coating liquid adjusting tank, and heated to 120 ° C. through steam in a jacket. A stirrer is started in this tank, and 14.4 kg of talc is charged. After 5 minutes, polyethylene [trade name: Suntech M2270, manufactured by Asahi Kasei Corporation] 1
9.8 kg, polyethylene glycol monomethyl ether [trade name UNIOX M2000, NOF Corporation]
1.8 kg, and heated and dissolved at 120 ° C.
Activate the blower before feeding the fertilizer, circulate the hot air of 70 ° C through the system including the jet tower and back filter for about 1 hour, and preheat the jet tower and bag filter.

The blower blow rate is 450N cubic m / hr.
And a granular fertilizer containing 29% of nitrogen and 3% of insoluble phosphorus [trade name: Kumiai Phosphorus Nitan 2903, Asahi Kasei Corporation]
Manufactured from 2.3 mm to 3.4 mm 30
kg is gradually injected into the spout tower, and the fertilizer is spouted.
Close the inlet and set the hot air temperature at the hot air generator outlet to 140 ° C.
When the temperature of the fertilizer in the jet tower reached 65 ° C., the liquid feed pump was started, and the coating liquid was fed at a liquid feed rate of 3.3 kg / min to start spraying. Although the temperature of the fertilizer in the spout tower decreased slightly immediately after the start of spraying, it was almost 6
It was constant at 5 ° C. After spraying for 13 minutes, the liquid sending pump was stopped, and the hot air was switched to cold air. When the temperature of the fertilizer in the spout tower became 40 ° C. or lower, the blower was stopped, and the resulting coated fertilizer was withdrawn from the discharge valve at the bottom of the spout tower. The coated fertilizer was sieved with a 2.3 mm and 4 mm sieve to obtain a product having an intermediate particle size. Coating was repeated by the same operation except that the residual heat time was changed to 10 minutes from the second batch, thereby producing a total of 10 batches. The yield of the product-coated fertilizer was about 33 kg for each batch, and the coating was cut and the weight of the coating was measured. As a result, the ratio of the coating contained in the coating fertilizer for each batch was 10.3% by weight.
The on-screen and under-screen coated fertilizer was 0.3 kg per batch on average for all batches.

3) Evaluation of coated fertilizer The dissolution rate of the manufactured coated fertilizer was measured. A plastic bottle is filled with 5.00 g of the coated fertilizer in a polyethylene net.
200 ml of distilled water is added to the bottle, and the bottle is left in an incubator at 25 ° C. for a predetermined number of days. When the predetermined number of days has been reached, the polyethylene net is taken out, washed with water, made up to 500 ml in total with the remaining liquid, and the nitrate nitrogen and ammonia nitrogen in the water are analyzed based on the fertilizer analysis method. Put the polyethylene net into a plastic bottle again, and add 200 ml of distilled water.
And left at 25 ° C. Repeat this operation. Table 1 summarizes the measurement results. The elution rate of the on-screen and the coated fertilizer on the 30th day was 8 to 40%, which was significantly higher than the elution rate of the product. What is important for the NP fertilizer for raising whole-cell-based fertilizer cells for seedlings is that the elution rate on the 30th day is low. Usually, when the elution rate exceeds 1%, the root pain becomes severe during the seedling raising period. In this example, the elution rates on the 30th day were all 1% or less, and a coated fertilizer satisfying the required performance could be stably produced.

[0025]

[Table 1]

[0026]

Embodiment 2 1) Apparatus for producing coated fertilizer Example 1 of the apparatus for producing coated fertilizer of Example 1 shown in FIG. 1 except that a guide pipe in a jet tower was removed.
In the same manner as in the above, an apparatus for producing a coated fertilizer was prepared. 2) Production method of coated fertilizer (urea fertilizer for application of whole rice seedling box fertilizer) On the day after Example 1, using the above-mentioned production apparatus for coated fertilizer,
A coated granular fertilizer was produced by the following operation. 414 kg of perchlor ethylene is charged into a coating solution adjusting tank, and heated to 120 ° C. through steam in a jacket. A stirrer was started in this tank, and 14.8 kg of talc and silicone-treated starch (trade name: Minipack S, manufactured by Nikka Co., Ltd.) 2.1
Input 6kg. After 5 minutes, polyethylene (trade name: Suntech M2270, manufactured by Asahi Kasei Corporation) 19.1k
g, and the mixture is heated and dissolved at 120 ° C. Activate the blower before feeding the fertilizer, circulate the hot air of 70 ° C through the system including the jet tower and back filter for about 1 hour, and preheat the jet tower and bag filter.

[0027] The blower blow rate is 450N cubic m / hr.
Then, 30 kg of urea fertilizer (trade name: Kumiai large-grain urea, manufactured by Mitsui Chemicals, Inc.) sieved from 2.3 mm to 3.4 mm is gradually charged into the jet tower to make the fertilizer into a jet state. Close the inlet and set the hot air temperature at the hot air generator outlet to 14
The temperature was raised to 5 ° C., and when the temperature of the fertilizer in the jet tower reached 70 ° C., the liquid sending pump was started, and the coating liquid was sent at a liquid sending rate of 3.3 kg / min, and spraying was started. The temperature of the fertilizer in the spout tower decreased slightly immediately after the start of spraying,
It was constant at approximately 70 ° C. After spraying for 13.6 minutes, the liquid feed pump was stopped, and the hot air was switched to cold air. When the temperature of the fertilizer in the spout tower became 50 ° C. or less, the blower was stopped, and the resulting coated fertilizer was withdrawn from the discharge valve at the bottom of the spout tower. From the second batch, coating was repeated by the same operation except that the residual heat time was set to 10 minutes, and a total of 10
Batch produced. The yield of the coated fertilizer was 33.5 kg for each batch, and the coating was cut and the weight of the coating was measured. As a result, the ratio of the coating contained in the coated fertilizer for each batch was 10.7% by weight. . Example 1,
After the completion of Step 2, the weight of the dust discharged from the bag filter was measured and found to be 0.95 kg.

3) Evaluation of coated fertilizer The dissolution rate of urea component in the coated fertilizer was measured by the same operation as in Example 1. Table 2 summarizes the measurement results. One of the important performance requirements for fertilizer for rice seedling box fertilizer application is
The elution rate on the 30th day is low. Usually, when the elution rate exceeds 3%, disorders such as seedling growth and yellowing appear during the seedling raising period. Furthermore, when the elution rate increases, the seedlings die. In this example, the elution rate on day 30 was all 3
% Or less, and could stably produce fertilizers satisfying the required performance.

[0029]

[Table 2]

[0030]

[Comparative Example 1] 1) Apparatus for producing coated fertilizer In the apparatus for producing coated fertilizer of Example 1, except that a bag filter was removed and a line entrance type cyclone 11 having a simple tangent diameter of 0.3 m was installed instead. In the same manner as in Example 1, an apparatus for producing a coated fertilizer was obtained. Fig. 2
Shown in 2) Manufacturing method of coated fertilizer By using the same fertilizer and the same coating liquid as in Example 1 and performing the same operation (there is no bag filter but the remaining heat time is 1 hour for the first batch), a total of 10 batches of coated fertilizer are used. Produced. No sieve flour was applied after coating. The weight of the coating was 33 kg for each batch, and the coating was cut and the weight of the coating was measured.
There was a coating of 0% by weight. 3) Evaluation of coated fertilizer The dissolution rate of the nitrogen component in the coated fertilizer was measured by the same operation as in Example 1. Table 3 summarizes the measurement results. In this comparative example, the elution rate on the 30th day was higher than that of the 7th batch and exceeded 1%.

[0031]

[Table 3]

[0032]

Comparative Example 2 1) Apparatus for producing coated fertilizer The apparatus for producing coated fertilizer of Comparative Example 1 was replaced with the apparatus for producing coated fertilizer in the same manner as Comparative Example 1 except that the guide tube in the jet tower was removed. 2) Manufacturing method of coated fertilizer On the next day of Comparative Example 1, the same fertilizer and the same coating liquid as those in Example 2 were used, and the same operation (remaining heating time was set to 1 hour) produced a total of 10 batches of coated fertilizer. The weight of the coating is
Each batch weighs 33.6 kg, cuts the coating,
When the weight of the coating was measured, each batch had a coating of 12% by weight based on the fertilizer. After the completion of Comparative Examples 1 and 2, the weight of the dust collected in the cyclone was measured and found to be 0.7 kg. 3) Evaluation of coated fertilizer The dissolution rate of the urea component in the coated fertilizer was measured by the same operation as in Example 2. Table 4 summarizes the measurement results. In this comparative example, the elution rate on the 30th day exceeded 3% in most of the batches. In addition, the dispersion of the elution rate for 30 days was large.

[0033]

[Table 4]

[0034]

According to the present invention, by using a device provided with a high-performance dust removing device between the gas outlet of the jet tower and the gas cooler of the present invention, the dissolution rate during the initial dissolution suppression period is reduced. It is possible to stably produce a large amount of time-dissolving coated fertilizer. At the same time, it is possible to prevent contamination of the device by dust.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an apparatus for producing a coated fertilizer shown in Example 1 of the present invention.

FIG. 2 is an explanatory diagram of an apparatus for producing a coated fertilizer shown in Comparative Example 1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spout tower type coating apparatus 2 Bag filter 3 Fin tube type cooling condenser 4 Roots type blower 5 Fin tube type hot air generator 6 Coating liquid adjustment tank with a stirrer 7 Plunger type liquid sending pump 8 Spray nozzle 9 Guide pipe 10 Vibrating sieve 11 cyclone cw cooling water sol condensed organic solvent st steam dr condensed water

Continued on front page F term (reference) 4D073 AA01 BB03 CA12 DC19 DC22 4D075 AA04 BB18Z BB24Y BB33Y CA50 DA11 DB32 DC50 EA07 EB01 EB13 4H061 AA02 AA03 DD04 EE35 FF08 FF15 GG15 GG19 GG47 GG51 H

Claims (5)

[Claims] 1. A coating apparatus for coating a surface of a fertilizer with a polymer by spraying and drying a polymer solution on a surface of a fertilizer, and reusing gas used for drying discharged from the coating apparatus into the coating apparatus from a gas circulation system. And producing a coated fertilizer, wherein between a gas outlet from the coating device and a gas cooling condenser provided in the gas circulation system, 1 to 1
The removal rate of 0 micron particles is 95% or more and 10 to 1
A method for producing a coated fertilizer, comprising: providing a dust removing device having a performance of removing a 00 micron particle of 99.5% or more to remove dust of gas used for drying. 2. A coating apparatus for coating a fertilizer surface with a polymer by spraying and drying a polymer solution on a surface of a fertilizer, and a gas circulation for re-introducing a gas used for drying discharged from the coating apparatus to the coating apparatus. System for producing a coated fertilizer including a system, between a gas outlet from the coating device and a gas cooling condenser provided in the gas circulation system,
The removal efficiency of 10 micron particles is 95% or more and 10
An apparatus for producing a coated fertilizer, comprising a dust removing apparatus having a performance of removing particles having a particle size of from 100 to 100 microns of 99.5% or more. 3. The apparatus for producing coated fertilizer according to claim 2, wherein the gas circulation system includes a gas circulation blower and a hot air generator. 4. The apparatus for producing coated fertilizer according to claim 2, wherein the dust removing device is a bag filter. 5. The apparatus for producing coated fertilizer according to claim 2, further comprising an apparatus for further classifying the coated fertilizer to remove powder and the like.