WO2016120317A1

WO2016120317A1 - Method for conditioning granular fertilizer material

Info

Publication number: WO2016120317A1
Application number: PCT/EP2016/051686
Authority: WO
Inventors: Harald Günter; Fabian Horbert
Original assignee: Maschinenfabrik Köppern Gmbh & Co. Kg
Priority date: 2015-01-28
Filing date: 2016-01-27
Publication date: 2016-08-04
Also published as: EP3250314A1; CA2975179A1; RU2674974C1; BR112017015339A2

Abstract

The invention relates to a method for conditioning granular fertilizer material, e.g., potassium chloride granular fertilizer material or potassium sulfate granular fertilizer material, wherein granular material is first provided, wherein the granular material is moistened with, e.g., water, and wherein an air flow is then applied to the moistened granular material and the moistened granular material is strengthened in the process, namely possibly by utilizing the granular material's own heat. Vapor is preferably removed from the moistened granular material by means of an air amount of at least 100 m³ per metric ton of granular material at an air temperature of below 45 °C.

Description

Process for conditioning fertilizer granules

Description:

The invention relates to a method for conditioning fertilizer granules. In the context of the invention, fertilizer granulate means in particular potassium fertilizer granules and more preferably potassium chloride fertilizer granules or potassium sulfate fertilizer granules. However, the invention also includes the conditioning of other fertilizer granules, eg. B. ammonium sulfate granules.

Fertilizer granules, for example potassium sulfate fertilizer granules or potassium chloride fertilizer granules, are produced, for example, by press granulation (compacting) in roller presses. In this case, the starting material (eg fine-grained salts) is compacted in roller presses and thus pressed into so-called scabs. These flat slugs are then crushed (eg in impact mills) and classified. In the production of potassium chloride fertilizer granules, the starting material (eg potassium chloride salts) is usually applied to the roll press dry and in a hot state. This is followed by conditioning by moistening the granules with water and then applying a stream of air to the moistened granules while solidifying them by utilizing the heat of the granulate. In this way, the abrasion resistance should be improved, so that unwanted dust or fine grain formation can be reduced. For this purpose, for example, in DD 136 956 proposed that (raw) granules initially in the fluidized bed to dedust, then wet with water and then solidify the granular surface by recrystallization processes in exploiting the heat capacity of the granules. The moistened granules are dried with strong air streams and then cooled with air, with both the

Drying and cooling in the fluidized bed can be done (see DD 136 956).

In contrast, in the production of potassium sulfate fertilizers, the starting materials are not pressed dry in practice, but the finely crystalline potassium sulfate is usually compressed with the addition of water in the roller press to the rag. Subsequently, the slug can be dried by a first process variant in a dryer and then granulated. A conditioning of the granules is not provided. The granules have in this case a low final moisture, but also the abrasion resistance is low. In a second process variant, drying of the slug prior to granulation is dispensed with, so that the moist slug is granulated. To increase the quality of the raw granules, this can be moistened after granulation by adding water. The moistened granules are then stored in large product storage for several weeks, so that the surface of the granules loosened by the addition of water recrystallizes and solidifies. In this way one obtains an end product with higher humidity but also higher abrasion resistance.

The methods used in practice for producing fertilizer granules, e.g. Potassium chloride or potassium sulfate fertilizer granules have basically proven themselves in practice, but they can be improved. - This is where the invention starts.

From DE 28 10 640 A1 a process for the production of granular products from a substantially consisting of sulfated potassium or ammonium salts fine-grained material by means of a high-pressure roller press is known, moreover, wherein the material to be pressed before the entry in the

Roll press is treated at elevated temperatures with water or steam. This should be in the material to be pressed a moisture content of 0.5 to 2.0 wt .-% and a temperature of 40 ° C to 50 ° C are set. The temperature of the material to be compacted should be kept below the condensation temperature of water vapor during the entire pressing process. The product withdrawn from the high-pressure roller press, preferably at a temperature of 55 to 95 ° C, consists of slugs, which are then ground. From the ground product is then the good grain, preferably separated with a mean grain diameter of 1 mm to 4 mm from the coarse and fine grain as a product and cooled to room temperature.

Furthermore, DE 39 18 523 A1 describes a method for preventing dust formation when loading or transporting granules or pellets, in particular fertilizer granules, such granules being produced by dry press granulation. The formation of dust during loading or transport is prevented by the use of a conditioning agent, wherein a liquid mixture (dust-binding mixture) of at least two organic substances is added, which are fully soluble with each other.

The invention has for its object to provide a method by which fertilizer granules and in particular potassium fertilizer granules, particularly preferably potassium chloride fertilizer granules or potassium sulfate fertilizer granules with low investment outlay and can be economically conditioned so that a storable product with low Unterkorn- or Fine dust formation and high abrasion resistance is provided.

To solve this problem, the invention according to a first aspect teaches a method for conditioning fertilizer granules, eg. B. Potassium chloride fertilizer granules, initially granules having a temperature of more than 40 ° C is provided, wherein the granules are moistened with water and wherein then the moistened granules are subjected to an air flow and thereby solidified by utilizing the intrinsic heat of the granules. It is provided according to the invention that the moistened granules (for solidification) with an air volume of at least 100 m ³ (cubic meters) per ton of granules (ie specific air volume of 100 m ³ / t) is dehydrated at an air temperature of less than 45 ° C. The specification of the mass refers to the moistened granules charged with the air.

The invention is based on the recognition that it is quite advantageous to moisten the (raw) granules and to apply a self-heating with an air flow, so that solidification and possibly smoothing of the surface takes place and thus the abrasion and the undesired formation of undersize or fine dust is reduced. However, the invention has recognized that it is not necessary to dry the moistened granules (with hot air) and then to cool (with cooling air), but that a product with excellent shelf life and quality can be obtained if (only) a disintegration takes place with very high air flows. While z. B. in a conventional system in the fluidized bed, first drying with hot air and then cooling with air at room temperature, can be dispensed with hot air drying in the invention, when the (cooling) air at room temperature with very high air flow of at least 100 m ³ , preferably at least 300 m ³ , z. B.

at least 600 m ³ per ton of granules is selected. Plant technology, it is therefore not necessary in z. As a fluidized bed plant both a drying zone and a cooling zone set up, but the Entwrasung can be done in the fluidized bed in a single zone or in several (identical) zones in which only air at room temperature or ambient temperature is supplied with very high air flow. The water vapor which escapes from the moist granules by evaporation (ie the vapor) is removed with the high air streams, so that the moisture is effectively removed from the granules and the desired solidification takes place. Of particular importance is the fact that the air used for Entwrasung has relatively low temperatures in the range of room temperature, so that in particular can be dispensed with consuming burner or burner stages for heating the air. Only if such a system is operated in extremely cold environment and consequently air with very low temperatures (eg near the freezing point or below) has to be drawn, can a slight preheating of the air be expedient in the context of the invention without however, temperatures of 45 ° C are exceeded. Overall, the system works accordingly energetically and technically very favorable. Particularly preferably, the air for Entwrasung in the invention has a maximum temperature of up to 35 ° C. The amount of air can be selected depending on the air temperature and the relative humidity (of the air supplied).

It is envisaged that the moistened granules will preferably be deve- loped in a fluidized bed system. In principle, the Entwrasung can also be done in other types of equipment.

If a fluidized-bed installation is used, the invention proposes that the moistened granulate be conveyed in a dewatering zone of the fluidized-bed installation.

Direction is descrambled with the described air flow without a drying zone is preceded by hot air.

The moistening can be carried out in a basically known manner in a drum or in a drum mixer. Such a mixture in the drum should at the same time provide for a rounding of the particles. However, the invention has recognized in a preferred development that a humidification in a drum is not mandatory, but that z. As well as the humidification in a wave mixer, z. B. a 2-wave mixer can be done. In this way, the investment costs can be further reduced.

By Entwrasung the water content of the granules to less than 1%, preferably less than 0.5%, z. B. less than 0.2% reduced (by weight).

The invention also relates to a device for conditioning fertilizer granules with a method of the type described. Such a device comprises a mixing device for moistening the (raw) granules and a Entwrasungsvorrichtung in which the moistened granules with an air flow of at least 100 m ³ per ton of granules is dehydrated at an air temperature of less than 45 ° C. The Entwrasungsvorrichtung is particularly preferably formed as a fluidized bed plant, the Entwrasung thus takes place in the fluidized bed. In a second aspect, the invention teaches a method of conditioning fertilizer granules, eg, potassium sulfate fertilizer granules,

wherein initially moist granules prepared by granulating a wet rag emerging from a roller press are made available, the granules being moistened with, for example, water, and subsequently an air stream being applied to the moistened granules, whereby it is dehydrated and solidified. Moist granules, which are produced from the rug, in the context of the invention preferably means a granulate having a moisture content of 0.5% by weight to 2.0% by weight. According to the invention, this already moist granulate is moistened (once again) with the addition of water, preferably with the addition of 0.5% by weight to 5.0% by weight, particularly preferably 1% by weight to 3% by weight. -% water, in each case based on the weight of the granules. The granules produced from the slug in this case has a relatively low temperature, since the previously abandoned in the press starting material is not (actively) heated and heating in the course of Pressgranulierens at most (passively) by the pressing or granulation. The invention is based in this second aspect, first of the recognition that in the course of the production of fertilizer granules, such as potassium sulfate fertilizer granules is not (always) necessary to dry the scab before granulation, so that dispensed according to the invention costly drying equipment can. The granules produced by the press granulation is therefore available in a moist state. Nevertheless, according to the invention, a further moistening takes place by the addition of water in order to dissolve the granulate surface. This is followed by cold hardening of the granule surfaces by crystallization of the dissolved salts. This is supported and accelerated according to the invention,

that the granules are acted upon without supply of heat with an air flow and thereby solidified and thus conditioned. This exposure to air is a Entwrasung without drying by heat. Such an admission with air and thus Entwrasung can preferably take place in a fluidized bed plant, and particularly preferably with relatively high air flows. Thus, the moistened granules are preferably devoured in the air quantity of at least 100 m ³ , preferably at least 300 m ³ , for example at least 600 m ³ per ton of granules. It is also worked with relatively low air temperatures, so that is dispensed in particular with a drying with hot air, but preferably air is used at room temperature, so that can be dispensed with expensive burner or burner stages for heating the air. Only when such a system is operated in extremely cold environment and consequently air with very low temperatures (eg near the freezing point or below) has to be pulled, in the context of the invention, a slight preheating of the air may be appropriate, but without Temperatures of 45 ° C are exceeded. A system works then energetically and plant technically very favorable. Particularly preferably, the air, which is applied to the moistened granules and thus dehydrated, a temperature of up to 35 ° C. The amount of air can be selected depending on the air temperature and the (relative) humidity (the air supplied).

The conditioning of the granules according to the invention, for example in a fluidized-bed apparatus without heat supply, results in the abrasion resistance being improved by 30% to 50% compared with conventional processes in which the (moistened) granulate is stored in large product storage units over several weeks , In addition, the possibly still necessary storage times to reach a salable moisture content of <

0.5 wt .-% greatly reduce and, accordingly, also reduce required storage capacity.

In particular, according to the second aspect of the invention, the subject of the invention is not only the conditioning method described, but also a method of producing fertilizer granules, e.g. Potassium fertilizer granules, most preferably potassium sulfate fertilizer granules. In this manufacturing process, starting material, e.g. fine-grained potassium salt, with addition of e.g.

Water moisturizes,

- The moistened starting material konnpaktiert in a roller press to a rag and

- The slug is comminuted (i.e., granulated) to form granules and optionally classified.

Subsequently, the granules are then conditioned in the manner described, that is, the granules are moistened with water and the moistened granules are then subjected to an air flow and solidified.

Preferably, the starting material is not heated prior to compaction so that it preferably has temperatures below 40 ° C. In the course of press granulation, ie compaction on the one hand and granulation on the other hand, there is likewise no (active) heating of the material, but at best (passive) heating by the pressing process and / or the granulation process takes place. The starting material is preferably added with the addition of water in an amount of 0.5 wt .-% to 2 wt .-%, for example 0.5

Wt .-% to 1, 5 wt .-%, based on the mass of the Ausgangsmatehals, moistened. The flake resulting from the compaction is particularly preferably comminuted in the moist state without prior drying, so that moist granules are made available, which is then moistened (additionally) in the manner described in the context of conditioning. In principle, however, the invention also encompasses production processes in which the slug is optionally dried before granulation.

As required, the (conditioned) granules are stored in a storage, e.g. a warehouse, stored in air for a predetermined period of time. According to the invention, this period can be significantly reduced compared to the known methods, so that the storage capacities as a whole are reduced.

The starting material is preferably moistened on the roller press just prior to application, e.g. in a mixer, e.g. a drum mixer or a two-shaft mixer.

For the moistening of the granulate produced by the press granulation, a mixer, e.g. Drum mixer used. Such a mixture in the drum can at the same time round off the particles. However, the invention has recognized in a preferred development that moistening in a drum is not absolutely necessary, but that, for example, also moistening in a wave mixer, e.g. a two-shaft mixer can be done. In this way, the investment costs can be further reduced.

In the course of conditioning, the water content of the granules is particularly preferably reduced to less than 1%, preferably less than 0.5%, for example less than 0.2%, by applying the air stream to the air stream.

reduced, based on the weight. If the desired values are not reached directly by conditioning air admission, the value can then be achieved by relatively short storage times.

A plant for producing fertilizer granules of the type described has at least one (high-pressure) roller press (compacting press) and a comminution device downstream of the roller press (for example, impact mill). Before the roll press, a moistening device, e.g. a mixer can be arranged. For the conditioning of the granulate produced by the pressure granulation, a mixing device for moistening the granulate is then preferably also provided, e.g. a wave mixer (e.g., two wave mixers). This is then preferably followed by a device with which the moistened granules can be acted upon by an air flow, e.g. a Entwrasungsvorrichtung, which is preferably designed as a fluidized bed system, i. the Entwrasung takes place in the fluidized bed, and more preferably without upstream hot air drying zone.

In the following the invention will be explained in more detail with reference to a drawing showing only one exemplary embodiment. Show it:

Fig. 1 shows a device for conditioning of fertilizer granules, in particular of potassium chloride fertilizer granules in a highly simplified schematic representation, in particular according to the first aspect of the invention and

Fig. 2 shows a device for the production and conditioning of

Fertilizer granules, in particular of potassium sulfate fertilizer granules, in particular according to the second aspect of the invention.

Figure 1 shows an apparatus for conditioning of fertilizer granules, in particular of potassium chloride fertilizer granules in a highly simplified schematic representation. Fig. 1 relates in particular to the first aspect of the invention.

The device according to the invention has a mixing device 1 and a disintegrating device 2 connected downstream of the mixing device 1, which in the illustrated embodiment is designed as a fluidized bed system 2.

Granules (or raw granules) are initially made available in the process according to the invention, specifically from a granulation unit 4 that is merely indicated. These are usually one (or more) roller presses or roller press with downstream painting unit. and screening level. The starting material, for. B. dried fine salt is compacted in this roller press and thereby pressed into so-called scabs. These slugs are then crushed or ground and classified so that the granules or raw granules are made available for the subsequent conditioning. The raw granules generally have relatively high temperatures of more than 40 ° C. after pressing granulation. This residual heat is utilized in the context of the subsequent conditioning. This conditioning is shown in the figure. The (warm) raw granulate G is moistened in the mixing device 1. This humidifying mixer 1 is formed in the embodiment as a two-shaft mixer. This is followed by the Entwrasungsvorrichtung 2 and consequently the fluidized bed plant. In this fluidized bed plant 2, the moistened granulate B is dewatered and solidified with an air quantity of at least 100 m ³ per ton of granules at an air temperature of less than 45 ° C. The supplied air L thus has a temperature in the range of room temperature.

On drying with hot air is omitted, so that no subsequent cooling is required. The fluidized bed system 2, which is used in the context of the invention, can therefore be shortened / reduced compared to conventional fluidized-bed systems, which on the one hand have a drying zone and, on the other hand, a cooling zone, so that the outlay on equipment is reduced. It can also be dispensed with corresponding hot gas generator for heating drying air.

With the method according to the invention, a product P, i. Conditioned granules with high shelf life and high quality, obtained.

FIG. 2 shows, in a greatly simplified manner, an apparatus for producing (and conditioning) fertilizer granules, in particular potassium sulfate fertilizer granules. Fig. 2 relates in particular to the second aspect of the invention.

An essential component of such a plant is a roller press 5, in which the starting material (for example potassium sulfate salt) is compressed and thus compacted. However, the raw material supplied to the roller press A is previously moistened with water, in a mixing device 6, which is the roller press 5 upstream.

The moist slug S emerging from the roller press 5 is comminuted in a granulating device 7, which can be designed as an impact mill, for example, and consequently granulated. It is particularly preferably provided to crush the scoop S in a moist state without prior drying. This is usually followed by a classification, not shown.

The (moist) granules G produced in this way are then conditioned according to the invention - optionally after storage or intermediate storage. For this purpose, the granules G is moistened in a mixing device 1 with water to dissolve the granule surface. Subsequently, the moistened granulate B is fed to a device 2, which in the exemplary embodiment is designed as a fluidized bed system, and in which the moistened granulate B is acted upon by an air flow L and thereby dehydrated and solidified. On drying with hot air is omitted, so that then no cooling is required. The fluidized-bed plant 5, which is used in the context of the invention, can consequently be shortened / reduced in size compared to conventional fluidized-bed plants, which on the one hand have a drying zone and, on the other hand, a cooling zone, so that the outlay on equipment is reduced. It can also be dispensed with corresponding hot gas generator for heating drying air.

The granules conditioned in this way have a very low moisture content as product P, so that it is immediately salable. If the humidity does not meet the requirements, it is possible to remove the granules from the fluidized bed plant 2 in a memory, for. B. a warehouse to store in air, so that after a relatively short period a salable product is available.

Claims

claims:

1 . Process for conditioning fertilizer granules, e.g. Example, potassium chloride fertilizer granules, initially granules having a temperature of more than 40 ° C is provided, wherein the granules are moistened with water and wherein then the moistened granules are subjected to an air flow and thereby taking advantage of the natural heat of the granules is solidified, wherein the moistened granules with an air quantity of at least 100 m ³ per ton of granules is dehydrated at an air temperature of less than 45 ° C.

2. Method of Conditioning Fertilizer Granules, e.g. Potassium sulfate fertilizer granules, wherein initially moist granules prepared by granulating a wet rag emerging from a roller press is provided, wherein the granules are moistened and then wherein the moistened granules are subjected to an air flow and thereby solidified.

3. The method of claim 2, wherein the granules with the addition of water, for example, 0.5 wt .-% to 5 wt .-%, preferably 1 wt .-% to 3 wt .-% of water is moistened.

4. The method of claim 2 or 3, wherein the moistened granules with an air quantity of at least 100 m ³ per ton of granules and / or an air temperature of below 45 ° C is dewormed.

5. The method according to any one of claims 1 to 4, wherein the moistened granules with an air amount of at least 300 m ³ , eg at least 600 m ³ per ton of granules is Entwrast.

6. The method according to any one of claims 1 to 5, wherein the moistened granules is dehydrated with air having an air temperature of below 35 ° C.

7. The method according to any one of claims 1 to 6, wherein the moistened granules are applied in a fluidized bed system with the air or dehydrated.

8. The method according to any one of claims 1 to 7, wherein the moistened granules in a Entwrasungszone the fluidized bed device is subjected to an air flow without upstream hot air drying zone.

A process according to any one of claims 1 to 8, wherein the granules are mixed in a mixer, e.g. a wave mixer, is moistened with water.

10. Method for producing fertilizer granules, e.g. Potassium sulfate fertilizer granules, wherein

- starting material, e.g. fine-grained potassium salt, with addition of e.g.

Water is moistened,

the wetted starting material is compacted in a roller press into a rag,

- The slug is crushed to form granules and optionally classified, and wherein the granules are then conditioned by a method according to any one of claims 2 to 9.

1 1. The method of claim 10 wherein the feedstock is not heated prior to compaction.

12. The method of claim 10 or 1 1, wherein the scab is comminuted in a moist state without prior drying and optionally classified.

13. The method according to any one of claims 10 to 12, wherein the conditioned granules are stored in a memory in air.

14. A device for conditioning fertilizer granules, in particular potassium chloride fertilizer granules or potassium sulfate fertilizer granules, according to a method according to any one of claims 1 to 9 with

- A mixing device for moistening the granules and

- A Entwrasungsvorrichtung in which the moistened granules with an air flow of at least 100 m ³ per ton of granules and an air temperature of less than 45 ° C can be acted upon.

15. Vornchtung according to claim 14, characterized in that the degasification device is designed as a fluidized bed system.

16. The apparatus of claim 14 or 15, characterized in that the mixing device as a wave mixer, z. B. as a 2-wave mixer, or as

Mixing drum is formed.