JPS58145685A - Manufacture of granular composite fertilizer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in a method for producing granular compound fertilizers.

Ammonia, phosphoric acid, and sulfuric acid are also produced using a tubular reactor.1. B, l (, Parker
, M, hjNorton, Q, Sal
Document by 1aday (FAI-IFDCSem1na
r/977 inNew Delhi, In
dia) and others.

This method has simpler structure and maintenance of the reactor than a method in which the reaction is carried out in a neutralization reaction tank equipped with a stirrer, and the heat of reaction can be effectively used for water evaporation, granulation, and drying operations. It has the advantage of being able to

The solution thus obtained is fed to a drum granulator or plunger, where it is mixed and granulated with other solid fertilizer substances and/or solid diluents and a large amount of circulating solid particles from the desired rC to remove moisture. However, a granular material of nota weight is obtained. This granular material is dried with hot air in a rotary dryer, and a product composite fertilizer with a desired particle size range is obtained in a classifier. Oversized particles are crushed, and undersized particles are crushed \the above-mentioned circulating solid particles. It is circulated to the granulator as

In this method, depending on the ingredients contained in the compound fertilizer, the granulation conditions, water balance and energy balance within the granulation system are affected by the granulation machine and rotary dryer. To maintain operating conditions, the amount of solid particles recycled to the granulator must be 2-g times the amount of final product removed from the system, and is typically within the desired particle size range obtained by the classifier. It is also necessary to return some of the particles to the circulation system.

An object of the present invention is to provide an improved method for efficiently producing a granular composite fertilizer containing two or more fertilizing ingredients selected from nitrogen, phosphate groups, and potassium.

The present invention provides a method for producing a granular compound fertilizer as described below.

In producing a granular compound fertilizer containing at least λ fertilizer components selected from nitrogen, phosphate groups, and potassium,
Phosphoric acid, sulfuric acid, and nitric acid are also used in 1. If a mixture of these and ammonia is reacted in a tubular reactor to produce ammonium phosphoric acid/hydrogen, ammonium phosphoric acid/hydrogen, ammonium sulfate, and ammonium nitrate, 7. The solution is introduced into a mixing tank and the water is evaporated to form a hot slurry with a liquid content of 1-0-90 volumes, or the water is evaporated and the particle size is 000μ of solid fertilizer material is also used, and the solid diluent and the melt of the fertilizer material are The aqueous solution is mixed to form a hot slurry with a liquid content of ≠0-90% by volume, and the resulting high temperature 1) is granulated in a spouted bed granulator or a fluidized bed granulator. The slurry is sprayed into the darkness of the sky to make the slurry adhere to the seed particles moving therein,
A method for producing a granular compound fertilizer, which comprises drying and cooling the enlarged particles by 7 inches.

In the process of the invention, ammonia is reacted with phosphoric acid, nitric acid, sulfuric acid, or a mixture thereof in a tubular reactor. It is preferable to use a mixed acid of phosphoric acid and nitric acid or sulfuric acid.The type of acid and the proportion used are appropriately determined depending on the concentration of each of the fertilizer components of the target compound fertilizer.

When phosphoric acid or a mixed acid of phosphoric acid and other acids is used, the ammonium phosphate produced has a maximum solubility when the molar ratio of ammonia/phosphoric acid is /,. When the molar ratio is larger than that of A, the solubility of ammonium phosphate decreases rapidly15, and solid ammonium phosphate precipitates and blocks the tubular reactor. Therefore, the molar ratio of ammonia/phosphoric acid in the tubular reactor is /, 3- /, 6
/, 3- /, , , t is desirable L7.

Ammonia to be further reacted with phosphoric acid is added in a later step as described below.

The tubular reactor has a structure similar to a short pipe and has a very small volume, so that it can contain solids, molten liquid, etc. Otherwise, it is unsuitable for adding and mixing an aqueous solution. Therefore, the reaction mixture produced in the tubular reactor is then introduced into a mixing tank where it is treated with VC, further to further increase the ammonia/phosphoric acid molar ratio (reacted with ammonia and L7).
I can't stand it. Water is evaporated from the reaction mixture by the sensible heat of the reaction mixture introduced into the mixing tank and the reaction heat in the mixing tank. Needless to say, if there is insufficient heat to evaporate water from the reaction mixture, steam can be used to heat the reaction mixture to evaporate the water. Further, in the mixing tank, various fertilizer substances may be added in the form of solids, melts, or aqueous solutions while stirring to adjust the component ratio and concentration of the desired composite fertilizer. Solid diluents can also be added with or in place of the fertilizer substance. The particle size of these solids is 50 μm 4000 μm.

Thus produced - Jf and the liquid content of the slurry is t
1-0-90 capacity section, preferably Kejo-Otsu 0 capacity section. If the liquid content is less than 0 volume, the slurry cannot be smoothly transported from the slurry mixing tank to the granulator by a pump, and if the liquid content exceeds 30 volume, the slurry cannot be transported smoothly in the granulator. Increased amount of moisture that must be evaporated 2.
This is disadvantageous because the amount of energy required increases, and the moisture content in the granules increases, requiring a separate dryer.

The high-temperature slurry obtained in this way contains fine solid particles, but since the solid particles in the above particle size range are uniformly dispersed, it is possible to use the spouted bed method or fluidized bed method described later. Slurry can be supplied to the granulator by a pump, and the spray nozzle of the granulator will not be clogged. It is preferable to stir the mixing tank at a speed of 30-300 revolutions per minute. The temperature of the slurry in the mixing tank varies depending on the composition of the target compound fertilizer, but it is usually
0°-/30°C is preferable11. stomach. ! Also, the residence time of the slurry in the mixing tank! It is preferably less than θ minutes, especially less than VCio minutes. A residence time of 20 minutes or more is not preferred because deterioration may occur due to interaction between raw fertilizer substances.

The high-temperature slurry prepared in the mixing tank is atomized by a pump into the granulation space of a spouted bed or fluidized bed granulator through a spray nozzle, and the seed particles moving in the granulation space are atomized. Oversized particles (after being crushed) and undersized particles that are discharged from the granulator as seed particles and separated from the desired particle size particles by a classifier are used. Spouted bed type Alternatively, a known fluidized bed granulator may be used.

Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings. A mixture of raw materials phosphoric acid, sulfuric acid, and nitric acid tobacco straw is supplied to the tubular reactor through three pipes and a pipe B. The total amount of ammonia required for the process, except for the portion where the molar ratio of ammonia and phosphoric acid exceeds /, is supplied through the tube 7 to carry out the reaction. The reaction mixture from the tubular reactor is conducted into the mixing tank by directly connecting the reactor outlet nozzle to the mixing tank: 2 VrC. The mixing tank has a rotation speed/j
The mixing tank is equipped with O-500/min high-speed stirrer 3! Nitrogen, phosphorus, supplied by pipe g or pipe 9 into
Mixing of a solid raw material containing potassium and fertilizing ingredients, an aqueous solution or a melt, or a solid raw material for dilution and a reaction mixture can be completed in a short time. In addition, if the molar ratio of ammonia and phosphoric acid exceeds t, the ammonia in the t portion is removed from the tube 10.
Mixing tank from K! to obtain a predetermined molar ratio. Simultaneously with these mixing or reaction operations, water is evaporated from the reaction mixture by the reaction heat generated in the tubular reactor/and/or straddle mixing tank. The evaporated water is washed with a mixture of water, phosphoric acid, and sulfuric acid from pipe 2.1 through pipe 2, along with a small amount of ammonia gas. The mixture of water, phosphoric acid and sulfuric acid is sent via pipe 27 to a tubular reactor/cleaner (only the gases are released into the atmosphere).

Examples of solid raw materials containing the above fertilizer ingredients are urea, ammonium sulfate, ammonium nitrate, ammonium phosphates, phosphoric acid processing, superphosphate lime, calcined phosphoric acid processing, sulfuric acid processing, chlorination processing, and metaphosphoric acid processing. , urea-aldehyde condensate fertilizer, magnesium silicate, calcium silicate, various trace elements such as zinc, manganese, mole
Includes budene, copper, iron, boron, etc. Examples of melts containing fertilizing ingredients include urea, ammonium nitrate, and the like. Examples of shredded solid materials for dilution include gypsum, bentonite, and the like. Examples of aqueous solutions containing fertilizing ingredients include aqueous solutions containing water-soluble substances among the above-mentioned fertilizer substances.

A predetermined amount of seed particles supplied from pipe /7 is present in the spouted bed granulator /j, and an upward spouted bed is formed in the granulator by the heated air flow supplied from pipe /B. At the same time, high-temperature slurry is sprayed upward from the mixing tank through pump t and pipe /3 through slurry spray nozzle /l at the bottom of the spouted bed granulator /j, and the sprayed droplets are transferred to the moving seed particles. The seed particles are allowed to adhere and become enlarged, and the enlarged particles are dried by air flow.

The air flow containing evaporated water from the high temperature slurry and fine particles generated in the granulator/j passes through a pipe/tube to a separator/9v.
After fine particles are removed from C, it is released into the atmosphere. The fine particles collected by the separator are not sent to the storage tank 22.

Particles enlarged in the granulator/j and having a large and small particle size are fed to the classifier, 2/ via a tube, 20, and then the particles with the desired particle size, which becomes the highest quality product, are crushed. Those with larger particle size,
It is classified into three types: small particle size and small particle size. Those with oversized particles are supplied to the crusher 2J-, those with undersized particles are stored once in the storage tank 22, and the final products are sent to the cooler 23.
After cooling, it is sent out of the system through pipe 24t. After being crushed by the oversize particle crusher 2j, it is recirculated to the classifier 2/ via v2 O. Once stored in storage tank 2, particles with too small a diameter are sent to granulator /3 via pipe /7.
The amount of recirculation to the feeder, in order to adjust the particle size distribution at the outlet of the granulator/j. According to the present invention, nitrogen, phosphoric acid, etc. are reacted from a famous reaction mixture obtained by reacting a mixture of phosphoric acid, sulfuric acid, nitric acid, etc. with ammonia in a tubular reactor. A granular compound fertilizer containing two or more components during processing can be efficiently produced.

In addition, since the slurry prepared from the above reaction mixture is subjected to spouted bed or fluidized bed granulation, the load on the drying process in the granulation process is small. This can be carried out using the heat of reaction with an acid. Furthermore, since it is supplied to the granulation process in the form of a slurry, any fertilizer substance or solid diluent containing any fertilizing ingredient at any concentration can be added at the time of slurry preparation to prepare the ingredients of the desired product. Then a tortoise is formed.

Therefore, Z/K7 can be used to meet any exterior product requirements. In addition, since the ammonia to be reacted with phosphoric acid is supplied separately to the tubular reactor and the mixing tank [7], precipitation of phosphoric acid/ammonium hydrogen in the tubular reactor (r) is prevented, and the reactor is not likely to be clogged. do not have.

Examples are shown below.

Example/ Nitrogen and phosphorus (
The content of P2O5 (in terms of P2O5) is very high! i' i
− and ≠ Otsu weight, and the particle size of the product is / −3.3 mm
A manufacturing test of a granular compound fertilizer within the range of 1 was conducted as follows.

The tubular reactor used had an inner diameter of 3; Qtnm, a length of
The mixing tank has an internal volume of 30 e and is equipped with an agitator running at 200 revolutions per minute. Further, the spouted bed type granulator has a cylindrical shape with an inverted truncated conical lower part, the diameter of the cylindrical part is 1,000 nm, and the internal volume is 230 i.

- 373ky of 00 liquid ammonia from outside the system via pipe 7
At 7 o'clock, via tube J-f, j in terms of P2O5 of 2.5'O
Phosphoric acid g00ky/hour, via pipe 2, 23C
7♂ weight of sulfuric acid 7 ky 7 o'clock and tube, 2♂ to 30C P2O5 conversion 3.2 hiro weight of phosphoric acid 2.2≠
7 kp 7 o'clock, except for the phosphoric acid from the tube 2 g, and the tube, 2. The remaining phosphoric acid was used as a solvent in the gas scrubber// to recover ammonia gas entrained in the water vapor separated in the mixing tank//, and then fed through pipe 29 to the tubular reactor//. Mixing tank, the reaction mixture! Sara K led to
Supplied through v/Q. o liquid ammonia/9.2
React with ky 1 o'clock, temperature ///'O, moisture lj vehicle volume %
Slurries 2, 9 and 3 from ammonium phosphate/hydrogen and ammonium sulfate containing solids + g
p/hour was obtained.

This slurry was passed through slurry pumps J and V/3 and then sprayed from a spray nozzle in a spouted bed granulator/3 operated under the following operating conditions to produce enlarged composite fertilizer granules precocious/10.
-3. ≠Okp/h was obtained at the outlet of tube No.0. Moreover, the water content in this particle is /, 5-. 2. J was in charge of weight.

Air blowing into the granulator t g, 30 ON m'
/ time air temperature to granulator / 70'C! Temperature inside the granulator: 7o-7taC seed particle supply amount,
2.7/0-. 2.7 Otsu Okp / Time Classifier! The average percentage of particles in the particle size range, oversized particles, and undersized particles in the final product taken out from
Doaty, J3 Section and 47 Otsu, 7%fah! l), final 'IA quantity fd J, ll-Otsu 0-. 2,310k
g It was 7 o'clock. The product particles were cooled to an appropriate temperature of ≠30 in a cooler, 23'7'' storage, and then discharged to the outside of the system via a pipe, 2≠0 Example! Nitrogen, phosphorus (in terms of P2O5) and The content of power + l (K2O equivalent) is about that.
/9, /9 and /sil ratio and the particle size of the final product is /
- We conducted a manufacturing test of a granular compound fertilizer within the scope of our company as a fertilizer.

0 'O liquid ammonia from outside the system through pipe 7! O9 ky 7 o'clock, via tube j, P2O5 of 2t'c
Conversion! ≠ Phosphoric acid in the weight department/, , 23; 3 kg/hour, via pipe Otsu,! 97 hours to sulfuric acid Otsu 3 of 9g weight of OC, and 30'0 P2O5 conversion after 2g of tube, 2
/, 7 parts by weight 3 g 3 ky 1 h of phosphoric acid were fed into the tubular reactor /1-1 in the same manner as in Example /1. The reaction mixture solution is introduced into the mixing tank 2, and the particle size is 0 from the outside of the new VC system.
00 μ or less room temperature potassium chloride 4 to 7 kg/hour and through pipe / 10C glue 6 weight, i%, % urea aqueous solution formula / 9 to 9 / hour and mix, /Qj;'C At this time, a slurry with a moisture content of 30.3 and a solid content of 30.3 was obtained at 97 hours. This slurry is passed through the slurry pump≠ and pipe /3 and then sprayed from the spray nozzle /4' in the spouted bed granulator /3 operated under the following operating conditions to produce enlarged composite fertilizer particles ZK63-1.31A3. kg/hour was obtained. Moreover, the water content in these particles was /-/J weight ratio.

Amount of air blown into the granulator 1! ;0ONm"/hour Air temperature to the granulator jOC Temperature inside the granulator 3 O 1 O 0 C seed particle supply amount
', t, 030-ku, 270 ky/hour classifier,
! / in the particle size range of the final product extracted from
The proportions of oversized particles and undersized particles are fidget average t coefficients 4, 70, and ≠L? J section, and the final product quantity is 33410-3. Tano 0kg It was 7 o'clock. Cooler, the final product! The mixture was cooled to VJC in step 3 and discharged from the system.

[Brief explanation of drawings]

The drawing is a flow sheet illustrating one embodiment of the invention. /...Tubular reactor...Mixing tank 3...Agitator//...Gas scrubber/j...Spouted bed granulator/9...Separator, 2/... Classifier, 2...Storage tank 2...Crusher, 27...Supplier Patent applicant: Toyo Engineering Co., Ltd.
Above Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] 1 at least 2 selected from nitrogen, phosphate groups and processing
In producing a granular composite fertilizer containing three fertilizer ingredients, phosphoric acid, sulfuric acid, nitric acid, or a mixture of straw and ammonia are reacted in a tubular reactor to produce ammonium phosphorus/hydrogen, A solution containing a mixture of ammonium ammonium, ammonium sulfate, and ammonium nitrate is produced, and the solution is introduced into a mixing tank to evaporate water to produce a hot slurry with a liquid content of ≠0-ta0 volume. Alternatively, water is evaporated from the solution and a solid diluent or a melt or aqueous solution of the fertilizer substance with a particle size of j0-4000μ is mixed with the solution at a high temperature with a liquid content of ≠0-90% by volume. A slurry is generated, and the high-temperature slurry thus obtained is sprayed into the granulation zone space in the spouted bed granulator or fluidized bed granulator, and the slurry is applied to the seed particles moving therein. let me,
A method for producing a granular compound fertilizer, which comprises drying and/or cooling particles enlarged with L~.