DE3017609A1 - METHOD AND DEVICE FOR PRODUCING GRANULATED MULTIPLE FERTILIZER - Google Patents

Description

Applicant Stuttgart, April 30, 1980

Societe de Prayon P 3851 S-G Prayon,! OrSt Belgium

Representative:

Eohler-Schwindling-Späth Patent attorneys Hohentwielst-r. 7000 Stuttgart

Method and device for the production of granulated compound fertilizer

The invention relates to a method for producing a granulated multi-component fertilizer, in particular a ternary fertilizer.

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There are in. essentially two different procedures for Production of a granulated three-component fertilizer known The »first processes are powdery, semi-finished "Solids are used as starting materials, while at the The second method uses a slurry or slurry that is granulated on a "bed of solids".

The division of beer from three-component fertilizers based on semi-finished solids takes place by measuring and mixing these semi-finished substances, which are in the form of a powder, in the presence of water or acidic liquids. The formation of a granulate is usually possible. Steam is usually supplied to heat the mass to be granulated and to dissolve some of the salts contained therein in order to form a binding agent between the powder particles and to dissolve them this © Ve ± se / die ^ Bsajunenballung: to effect the granulate grains. The ready-made products, which are used as starting materials for the production of ternary fertilizers, are usually ammonium nitrate and urea, simple and concentrated superphosphates, binary phosphorus-nitrogen compounds such as mono- and diammonium phosphates, potassium chlorides and potassium sulfates, ; other components containing additives, such as magnesium, sulfur and trace elements, substances which contain one or more of the components specified above. as well as natural phosphates.

The water can in this process, according to the desired Composition of the fertilizer, more or less completely replaced by sulfuric acid »phosphoric acid or nitric acid, those with certain der-used half-finished products responded. In this case, anhydrous ammonia or another base is used towards the end of the Granulation used to neutralize the excess acid. The operation of mixing and granulation can take place in "known apparatuses" such as Droaiiel and Telle-granulating devices as well as various mixers:

After granulation, the product is dried in a furnace and, after cooling, in a sieve device

calibrated. The products that are too fine and the products that are too large are if necessary after comminution, for granulation returned.

The other process, which is from a slurry or a pulp is particularly suitable for an integrated system in which the production, of the Dreiitoffdünger directly with the. Exposure is linked by phosphates, for example by means of nitric acid, heavy acid, phosphoric acid or Mixtures of these acids can be made .. In this case Process is in the slurry, from which one may have removed a part of the lime nitrate formed one or other semi-finished, solid material put in, and it is this slurry by mixing with-

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Products returned by a screening device are, for example, granulated in one of the granulating devices specified above *

The method of granulation using a slurry has several advantages over granulating the solids as described above. Because the active ingredients are suspended in a liquid, the various ingredients get better in Brought into contact and can therefore react better with each other in order to reach the final state of the reaction. Such a This process does not take place with granulated three-component fertilizers instead, 'where a mixture of solids or slightly doughy substances is assumed, where the reactions continue in the end product, which disintegrate in the process or can clump together-.

If a slurry is assumed, it finds the Formation of the granulate grains by covering, a core with several successive layers of the slurry in place, making the granules a better one Preserved mechanical strength and, as a result, the risk of destruction of the granulate is lower. Finally a slurry is usually more homogeneous than one Mixture of solids * so that. even in that from a slurry formed granules the active ingredients of the fertilizer are distributed more homogeneously than in a simple one Mixture of solids

An important part of the known process is involved which the granulate is made from a slurry consists in the fact that it is necessary must take place in a plant in which a digestion of phosphates by nitric acid, phosphoric acid and / or Sulfuric acid takes place.

In contrast, the invention is based on the object of a new method for producing a granulated Compound fertilizer to indicate what the advantages of both known processes combined, which have been briefly described above.

This object is achieved according to the invention in that an ammonium nitrate or urea solution and at least a powdery substance containing one or more fertilizing constituents, such as simple or concentrated superphosphate, binary phosphorus-nitrogen compounds, such as mono- or diammonium phosphate, Potassium chloride and sulfate and / or natural phosphates, made at an elevated temperature of a slurry and from this slurry by mixing with a powdered fertilizer, especially that when sieving of the granulate produced powdery residue, a granulate - is produced.

The invention also has a device for carrying it out of the method according to the invention to the subject «This

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Device comprises at least one, heated and. with a Eühreinrichtxing provided reactor in which on the one hand the powdery substance in the hot ammonium nitrate and / or waste Urinary solution "can be slurried" and on the other hand “There is an action between the solution and the powdery one Substances can take place *

Finally, the invention also comprises a granulated multi-component fertilizer which was produced by the method according to the invention or using the device according to the invention for producing the granulated nutrient fertilizer . . ■ -. "-.

Further details and embodiments of the invention result itself «.us the following description, in which as not limiting examples several specific embodiments of the process for the production of granulated fertilizer and a special embodiment of a device for Production "such fertilizer has been treated *

The attached drawing shows a schematic of a device for the production of granulated fertilizer.

The inventive method for producing a granulated multi-component fertilizer consists essentially in a Prepare slurry by at elevated temperature a solution of ammonium nitrate and / or urea with at least one powdery substance brought to heat

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where the as is a simple or focused Superphosphate to binary phosphorus-nitrogen compounds such as mono- or diammonium phosphates, and potassium chlorides -sulphates and / or natural phosphates can act, so to substances well known in the manufacture of fertilizers, and then the resulting slurry or the slurry thus obtained by mixing with a powdery To granulate fertilizers, which in particular may be the fine residues that are returned when the granulate is sieved.

In some cases, an ammonium phosphate solution can be added to the ammonium nitrate and / or urea solution as a supplement. The amount of ammonium phosphate solution is usually less than 20% and preferably less than 10 % of the total amount of fertilizer obtained.

The ammonium nitrate and / or urea solution used contains very little water. The amount of water is preferably only 4 to 15% by weight of the solution.

The solution is made with the above substances reacted at a temperature which is between 75 and 100 ° C and preferably between 80 and 90 ° C, to ensure good flowability of the slurry. obtain.

In order to obtain the greatest possible yield from the granulation, depending on the desired composition of the fertilizer, the weight of the solution used

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in relation to the amount of the pulverulent substance used so that a slurry or slurry is obtained which contains 50 to? 0 % and preferably 55 to 60 % Feetoff to the total amount of the slurry or pulp The final slurry is adjusted so that it is between 4 and 10 % and preferably between 4 and 7% with respect to the total amount of slurry or slurry evaporation is reduced to an absolute minimum.

The simultaneous adjustment of the solids and liquid content as well as water, apart from the dosage of the amount and the concentration of the urea or nitrate solution, is achieved by adding commercially available phosphoric acid with a content of 50 to 52 % Pp ⁰ S ^{un < i} of anhydrous ammonia to the slurry. The amount of ammonia is chosen so that the molar ratio HH, to H ^ PCL is between 1.35 and 1.40, so that the ammonium phosphate solution thus formed retains maximum solubility.

To adjust the acidity of the slurry before granulating reduce the calibration, for example, as a result of the addition of Phosphoric acid, ammonia is introduced into the slurry as a neutralizing agent prior to granulation.

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The amount of powdery «! Fertilizer that is returned and is mixed with the pulp or the slurry during the granulation, this is generally 1 to 5 times and especially 1 to 2 times the Amount of slurry.

After granulation, the product obtained is dried, possibly subsequently cooled and finally calibrated, for example by sieving. The above-mentioned recycled fine-grain fertilizer that is used in granulation is preferably formed from a part of the material that is eliminated in the calibration.

As already indicated above, the attached drawing shows a device or system in a schematic representation for the production of fertilizer according to the method described above. This system essentially comprises a storage container 1 for the hot ammonium nitrate and / or urea solution, and a number of funnels 2, 3 and 4, which the solid, powdery! Contain starting materials, such as for example superphosphates, binary phosphorus-nitrogen compounds, potassium chlorides and sulfates, etc.

The main part of the plant comprises at least one reactor for the slurry or the slurry, in which the solid starting materials, which are fed from hoppers 2, 3 and 4, in a hot ammonium nitrate and / or urea solution are suspended, which is fed from the container 1 o In the illustrated embodiment are two

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Reactors 5 and 6 are available, which are connected in series. The arrow 7 indicates the supply of the solution from the Container 1 to the first reactor 5, while part 8 is the supply of the solid starting materials to the same reactor 5 illustrated. The solution can be supplied, for example, by means of a double-walled, insulated line take place, in which saturated water vapor circulates, while the supply of the powdery substances ait of a simple conveyor belt that runs along under the funnels. The dosage of the powdery Substances can be done in any known way, «·! it through • in a volumetric metering or by weight by means of an automatic scale, which is not shown in the drawing is shown. Depending on their grain size, these starting materials can be screened and fed into the reactors to get broken.

The reactors, which have a certain volume, are provided with drills 9 and 10 and heating coils 11 and 12. Accordingly, a slurry or slurry-forming suspensions 13 and 14, which by mixing the solution supplied from the container 1 alters the powdery solution supplied from the funnels 2, 3 and 4 Substances have been obtained, kept at a temperature at which the mixture is as homogeneous as possible and has good flowability, so that it is in the suspension running reactions can run completely under ideal settlements.

In addition to the production of a homogeneous mixture between the solution fed in from the container 1 and the solids fed in by the funnels 2, a certain amount of evaporation of water takes place in the heated reactors 5 and 6, very dilute solution runs out to raise the concentration of the resulting slurry to a value that is necessary for the following operations. If necessary, a certain amount of phosphoric acid can be fed to one of the reactors, for example reactor 5, as indicated by arrow 26. The reactor 6 is successively followed by a granulator 15 »for example a drum granulator, a dryer 16 and a cooler 17. The granulated products leaving the cooler 17 fall into a sieve device 18 in which the granulate is calibrated, for example by means of two sieves 19 and 20 arranged one above the other. The grains retained between the sieves 19 and 20 have the desired dimensions and therefore form the granulated one Commercial fertilizer that can be delivered to a packing device, as indicated by arrow 21.

The large grains that do not pass the upper sieve 19, are fed to a crusher 22, while the fine grains, which pass through the sieve 20, are fed into a hopper 23 to be collected. These fine grains and the broken grains are then fed to the entrance of the granulator 15 fed, as indicated by the arrow 24, said that they were the

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form recycled manure intended to be used as Carrier material for the formation of granules with the slurry to be mixed up. In the absence of a traceable Product, for example with a very good yield granulation, a portion of the granulated fertilizer, which forms the oil product can be returned as it the arrow 21a indicates.

The arrow 25 shows the possible supply of ammonia as Heutralisationsmittel from a storage container 28 to Granulator 15 on the supply of ammonia from container 28 can also take place to bins 5 and 6 as it is the arrow 27 indicates.

In the granulator 15, the returned according to the arrow 25, fine particles enveloped by the slurry, which forms several successive layers until relatively hard granulate particles of a certain size are formed. The dimensions of the granules are among others a function of the residence time in the granulator, the composition and viscosity of the slurry, etc. The working conditions are generally determined experimentally in such a way that approximates the amount of the powdery Product can be set, which is to be returned to the granulator 25 according to the arrow 24.

The invention will now be made more practical with the aid of some Examples of the production of a ternary fertilizer by the method according to the invention and by means of the described Device explained in more detail.

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Example 1; Production of a ternary fertilizer 17-17-17 based on an ammonium nitrate solution.

4-15 kg of a hot, 90% ammonium nitrate solution with a temperature of 85 ° G were fed to the two series-connected reactors 5 and 6, where they were mixed with the powdery starting materials which were fed from hoppers 2, 3 and 4, namely with 307 kg "binary phosphorus-nitrogen compounds with a content of 11 % ammonium nitrogen and 49 % ^ ₂ ⁰ S ' ¹ ^ kg dicalcium phosphate with a content of 43 % ϊ ^> ₂ ° 5 ^{and 282 k} 6 potassium chloride with a content of 60.5 % K _? 0. As indicated by the arrow 26, 15 kg of liquid phosphoric acid containing 54% Pp ^ S were also fed to the reactor 5. In this way, a slurry or slurry was obtained 56 % solids but only 4.8% water The temperature in reactors 5 and 6 was maintained at about 80 ° G.

In the reactors take place between the suspended The following reactions take place:

KGl + NH ₄ NO ₅ -> KNO ₅ +

KGl + ammonium phosphate ^. Potassium phosphate +

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Thanks to this reaction takes place the formation of potassium nitrate ^ and potassium phosphate as well as ammonium chloride instead., which Substances in terms of behavior and mechanical Resistance of the granules produced as well as to the Fertilizing properties of the final ternary fertilizer. are to be drawn.

The residence time of the products in the reactors was about 40 minutes * The slurry thus produced was then passed into the granulator 15, which was also fed with the recycled products, which are essentially powdery Condition. The amount of recycled materials was 1.7 to 2.1 times the total amount of the slurry, which was fed from the reactor 6. In addition, 3 kg of ammonia were put into the granulator 15 as a neutralizing agent introduced as the arrow 25 shows. One received on this Way 1 O37 kg of granulated fertilizer, what with the amount of " used raw materials. -----

By drying and evaporating 37 kg of water, 1,000 kg of the product were obtained with a moisture content of 1.3%, the content of 17 % total nitrogen, 6.5% of which as nitrate nitrogen and 10.5 % as ammonium ^ -, nitrogen, 17 % phosphoric anhydride and 17 % K ^ O contain.. ^

Example 2: Production of a ternary fertilizer 15-22-12 on the basis of a urea solution

258 kg of a hot 90% urea solution at a temperature of 110 ° C were fed to the two series-connected reactors 5 and 6 and mixed therein with powdered starting materials that were fed from funnels 2, 3 and 4, namely 233 kg of binary phosphorus-nitrogen compounds containing 11 % ammonium nitrogen and 49 % P ₂ ° 5, 242 kg of simple superphosphate with a content of 19 % P ₂ ° 5 ^{and 1} ^ 8 kg of potassium chloride with a content of 60.5 # K ₃ O. Vie indicated by the arrow 26, the reactor 5 were fed 90 kg of phosphoric acid with a content of 54% P ₂ O ₅ and, as indicated by the arrow 27, 15 kg of ammonia. In this way a slurry was obtained which contained 65 % solids but only 5-8 % water. The temperature in reactors 5 and 6 was kept at 90.degree.

In addition to a partial combination of phosphoric acid with ammonium, the following reaction takes place between the products in the suspension:

KCl + ammonium phosphate ^ potassium phosphate + HH ^ Cl.

This reaction leads to products that are important for the good behavior and mechanical resistance of the obtained Granules are particularly cheap. The residence time of the products in the reactors was about 55 minutes.

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The slurry obtained was then fed to the granulator 15, which was also loaded with returned products. The amount of returned product was since «2.4 to 2.9 times the dee supplied by the reactor 6 Porridges. In addition, 15 were used as a neutralizing agent in the granulator 4 kg of ammonia introduced, as indicated by arrow 25. In this way, 1 052 kg of granules were obtained Fertilizer, which corresponded to the set amount of the starting materials.

Drying and evaporation of 52 kg of water gave 1000 kg of the product with a moisture content of 0.8 Ji, which had a content of 15 % total nitrogen, 22 % phosphoric anhydride and 17 % Ko °.

From the above description it can be seen that the Process according to the invention in a classic plant for Mixing of Feeter, powdery raw materials can take place through reactors for the slurry and a storage tank for the hot ammonium nitrate or urea solution is added. It enables the inventive Process to produce fertilizers of any composition and therefore the many different recipes apply that are possible with tertiary fertilizers and that have been used in mixing plants so far. Has the obtained fertilizer has the quality of one from a slurry granulated fertilizer obtained from it.

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Incidentally, the fact that hot liquids containing little water are used as a starting point has the consequence: that by simple cooling a direct solidification of successive, closed layers of the granulate particles he follows.

This results in a very strong increase in the yield the granulation and the capacity of a given granulator as well as a dryer of certain dimensions and heat output achieved in comparison to known methods.

It goes without saying that the invention is not restricted to the embodiments described, but that variations can be considered without departing from the scope of the invention. In particular, the method according to the invention can be used for the production of fertilizers of any desired composition, in particular also binary fertilizers.

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Claims (1)

-κ * Pat en fc claims ii ch e 1. Process for the production of a granulated multicomponent fertilizer s, characterized in that from an ammonium nitrate or urea solution and at least a powdery substance containing one or more fertilizing constituents, such as simple or concentrated superphosphate, binary phosphorus-nitrogen compounds, such as mono- or Diammonium phosphate, potassium chloride and sulfate and / or natural phosphates, a slurry is produced at an elevated temperature and from this slurry by mixing with a powdered fertilizer, especially that when sieving the granules produced resulting, powdery residue, a granulate is produced « 2 »Method according to claim 1, characterized in that a hot solution with a content of 85 to 96% by weight Ammonium nitrate and / or a hot solution with a content of 85 to 95% by weight urea is used » Method according to claim 1 or 2, characterized in that that the processing of the starting materials at a temperature between '/ 0 and 100 G, preferably between 80 and 90 ° 0. 03Q047 / 0797 4- _o Method according to one of the preceding claims, characterized in that such an amount of the solution and the pulverulent substances is used that the slurry contains 50 to 70% w / w solids, based on the total amount of the slurry. 5 · oinsin method. the previous claims, characterized in that such an amount of the solution and the powdery substance is used, that the slurry is 4 to 10 and preferably 4 to 7% by weight Wassor, bozogon on the total amount of the slurry, contains » 6. The method according to the preceding claims, characterized in that for setting the PpO, - content of the fertilizer produced Liquid phosphoric acid is added to the slurry. 7 method according to one of the preceding claims, characterized in that the slurry is neutralized with liquid or gaseous ammonia is added « 8. The method according to any one of the preceding claims, characterized in that "that part of the Slurry containing water is evaporated before granulation. 030047/0797 017609 9 · The method according to any one of the preceding claims, characterized in that the amount of the granulation recycled fertilizer is 1 to 3 times the amount of the slurry « 10. The method according to any one of the preceding claims, characterized in that the by mixing the Slurry with the powdered fertilizer product obtained dried and for example by Sieving is calibrated, and that at least part of the material precipitated during calibration, if applicable after previous breaking, is returned to the granulation, so that it is at least a part of the powdered fertilizer used in granulation «. 11. Device for performing the method according to one of the preceding claims, characterized in that that they have at least one heated and with a stirring device (9, 10) provided reactor (5, 6) for slurrying dei3 powdery substance in the hot Ammonium nitrate and / or urea solution. 12. The apparatus according to claim 11, characterized in that it has at least two reactors arranged in series (5 »6) includes. 030047/0797 13 · Device according to claim 11 or 12, characterized in that the reactors (5 ", 6) are provided with heating coils (11 and 12)» Device according to one of Claims 11 to 13, characterized in that the possibly last reactor (6) is followed in succession by a granulator (15) , a drying and a sieving device (16, 17 or 18). 15. More material fertilizer, produced by means of the process 'according to one of claims 1 to 10 and / or by means of the device according to any one of claims 11 to 14. O3G047 / O75T