DE1121082B - Equipment for granulation and drying of broad-form fertilizers - Google Patents

Description

GERMAN

PATENT OFFICE

P 24238 IVa / 16

REGISTRATION DATE: JANUARY 13, 1960

NOTICE THE REGISTRATION AND ISSUE OF EDITORIAL: JANUARY 4, 1962

The numerous types of mineral fertilizers require different ones depending on their composition Devices for their manufacture.

The fertilizers currently most frequently used are the mixed fertilizers, which contain the three elements N, P, K in addition to possible other additives, namely stabilizers, trace elements, pesticides etc. included.

These different fertilizers, regardless of how they are made, are in a final phase transferred, in which they are hard and easily spreadable, rounded granules with a uniform grain size are present. The treatment required for this is generally carried out in two stages, for each of which requires a separate device.

In the first stage, which is the actual granulation, crumbly, soft grains are produced, and in the second stage these are then converted into hard granules, usually by drying.

Although the procedure is in principle the same for the different fertilizers, they vary in the Practice depending on the fertilizer to be treated the embodiments, and as a result must the necessary facilities also differ from one case to another. That means that each certain fertilizers require special equipment. For this reason, the manufacture requires different fertilizers in one and the same factory take a very considerable amount of material and Costs and a large space requirement.

The device according to the invention eliminates these disadvantages.

The device according to the invention for the production of the most varied of dry, granulated fertilizers, which go through a granulation stage and a drying stage consists in a manner known per se from two adjacent revolving rooms, the front of which is the granulator forms and has at least one longitudinal line for the supply of hot gases and the subsequent space is designed as a dryer. The invention consists in that the spaces of a single tubular, rotatable housing are enclosed, the longitudinal line by perpendicular lines extending therefrom feeds a gas inlet running along the room, which consists of a stationary wall, whose edge in contact with the housing forms a scraper and the other edge Edge, which has a certain distance from the housing, represents a ramp over which the gases be introduced into the interior of the fertilizer mass in motion in the granulator.

Device for the granulation and drying of pulpy fertilizers

Applicant: Potasse et Engrais Chimiques, Paris

Representative: Dipl.-Ing. E. Prince

and Dr. rer. nat. G. Hauser, patent attorneys, Munich-Pasing, Bodenseestr. 3 a

Claimed priority: France of February 5, 1959

In contrast to the invention, form in the known devices of the type described Granulator and dryer are two separate rooms, separated by a kind of chimney, with hot air for the drying device is fed to the chimney through a pipe. The granulator and the dryer can rotate at different speeds, and the position of the Granulator relative to the drying device can change if only the granulated product is inserted into the center of the drying device.

In contrast, in the device according to the invention, the granulator and the drying device form a unit, which in particular simplifies the construction of the device and less driving force requires.

The processes taking place in the facilities are also different: In the known facility granulation is effected by adding water vapor, which is caused by condensation ensures the desired moisture content on the particles.

According to the invention, the granulation is achieved by evaporation as a result of a calorie

109 758/359

supply or released heat of reaction. This calorie intake can be achieved through hot air or hot gases take place, the hot gases can react at the same time, in which case those in the reaction The heat released is used for evaporation.

The way in which the gas flow is fed in is also different. In the known system, the Steam is supplied through longitudinal tubes which open into the free space of the granulator. In contrast for this purpose, according to the invention, the hot gases are fed into one on one side through the rotating housing limited space introduced. The wall side of this room forms a scraper, which a Prevents the mass to be granulated from settling. The opposite wall side of the room forms a kind of ramp, which enables the introduction of the hot gases directly into the mass to be granulated.

This results in a very considerable technical advance, since the calorie yield through the direct ao Heat transfer to the mass is quite excellent; in other words, it becomes granulation required amount of heat reduced to a minimum.

A special embodiment of the invention allows furthermore a chemical reaction in the solid, moist phase by being in front of the hot gases blowing in gaseous reactants.

Finally, the device according to the invention enables a very versatile application, which in the known establishment is not the case; this is only intended for a limited area of application and requires the addition of water which later has to be removed again in the dryer, whereby of course, the capacity of the facility is reduced and the calorie consumption is increased will.

Further details of the device of the invention emerge from the following description. In the drawing shows

1 shows a side view in longitudinal section of a device according to the invention,

FIG. 2 shows a vertical cross section through the granulator on an enlarged scale compared to FIG along line 2-2 of FIGS. 1 and

Figures 3 to 7 are schematic representations of the operation of the device when treating various types Fertilizer.

In Figs. 1 and 2, 1 denotes the tubular housing which is driven by a motor 2 and bands and rollers 3 and 4 are set in rotation about its axis.

The cylindrical housing 1 forms two adjacent spaces 5 and 6. The front space 5 with an inlet opening 7 represents the granulating device. Its inner wall 8 is smooth, and its Diameter is at least equal to its length to avoid the risk of deposits and clogging avoid.

In the granulator 5 is a scraper forming Gas injection device 11 arranged. She possesses in a fixed, vertical, opposite the vertical plane of symmetry slightly inclined plane several lines 12, which at the same time through a channel 13, the fresh air or hot gases under pressure, e.g. B. combustion gases or gaseous Reaction participants, feeds, are fed. The lines 12 are connected to a room 14, which is formed by a punched wall 15, which is at a small distance from the Housing 1 and located parallel to its surface line. The front edge 16 of the wall 15 is located with the wall 8 in contact and forms a scraper. The other, at a certain distance from that Wall 8 located edge 17 represents a ramp for blowing gas.

In its rear part, the partition 15 is surmounted by a plate 18, which a second space 19 forms and ends in a ramp 21 which is located substantially above ramp 17.

Lines 22, which are assembled with lines 12 and pass through, open into space 19 a line 23 are fed through which gaseous reactants, e.g. B. ammonia or Carbonic acid gas.

The following also open into the granulator 5:
a chute 25, which is fed through a funnel 26 and enables the supply of solid, powdery reactants as well as fine materials carried in the circuit,
one or more small diameter conduits, such as B. the line 27 for supplying water and liquid reactants,

at least one large diameter line, e.g. B. the line 28, which enables the supply of pulpy substances or crystal pulps with greater viscosity.
Finally, an axially removable channel 29 runs transversely through the granulator 5 and is closed off by a guide plate 30 which protrudes into the front part of the dryer 6.

At the inlet end of the granulator, but outside it, there are also several air inlets provided, namely

the line 31 connected to the channel 29 by a throttle valve 32, which can be fed with hot, compressed air from a heating chamber (not shown),
the line 33 connected by a valve 35 to the line 13, which can be fed with compressed, cold air supplied by a compressor,

the feed line 36 for gaseous reactants, which opens into the line 13 behind a valve 37.
Finally, a bypass 38 provided with a valve 39 is also provided between the lines 31 and 13, and a valve 41 is provided in the line 23.

This entire arrangement enables the granulator to be fed in a wide variety of ways.

The elongated dryer 6 has a known internal structure: on a helical part 42 with a smaller diameter than the granulator 5 is followed by a smooth part 43 and then a discharge system, which consists of a plurality of radially arranged metal sheets 44 which are mounted on blades 45 sit.

The cylindrical housing 1 opens into a chamber 51, which has a funnel-shaped part 52 to Has delivery of the fertilizer and the upper part of which has a pipe socket 53 through which it with the cyclones 54 and a fan 55 is in communication.

When the device is in operation, the housing 1 is set in rotation in the direction / by the motor 2.

The starting materials required for the production of the fertilizer are depending on their physical Characteristics introduced into the room 5 through the corresponding feed lines.

During the rotation of the housing 1, the material to be granulated contained in the space 5 forms 50 a blanket covering panels 15 and 18. The into the rooms 14 and 19 through lines 12 and 22 introduced gases occur at the level of the ramps 17 and 21 at the point at which the ceiling of the material to be granulated 50 has its greatest strength, from what a very good contact between the gas and the mass to be granulated guaranteed. One can be very effective in this way Achieve drying of the mass 50. If the introduced gases react with the mass, prevents the special arrangement of the ramps any risk of clogging.

On the other hand, the front edge 16 of the wall 15 causes the wall 8 to be scraped off all over Length and at the same time a stirring of the mass as well as a permanent cleaning of the granulator under Avoidance of solid build-up. The risk of clogging of the granulator is therefore avoided.

As a result of the difference in the diameters of spaces 5 and 6, the granulated mass occurs progressively in the dryer 6, where they once the action of entering through the channel 29 and through the guide plate 30 distributed hot gases and on the other hand the action of a in the longitudinal direction passing through, supplied by the fan 55 fresh air flow can be exposed. the various parts, namely the screw turns 42 and the discharge system (sheets 44 and Blades 45), ensure an intense contact between the moving granular Mass and the gases flowing through it.

The following examples show that the device described for the treatment of a variety important fertilizers of very different types and compositions can be used.

a) Powdered fertilizer

45

The solid components making up the fertilizer are fed into the granulator through the chute 25 introduced (Fig. 3). You then give the fines that have arisen during the sieving of the end product (return material) to. The line 27, which is provided with an atomizer at its end, leads to granulation of the fertilizer required water. Other aqueous solutions can also be used instead of water can be applied to the fertilizer mass to be granulated in a manner known per se. It is this Solutions from

Ammonium nitrate or sulphate to increase the nitrogen content of the fertilizer, Ammonia or a mixture of ammonium nitrate and ammonia to neutralize the Product,

Ammonium or potassium phosphate, which in the form of their solution at the same time as the fertilizer be granulated.

The amount of liquid added is such that the water content of the mass is between 6 and 9%. Furthermore, the axial channel 29 is attached, through which hot gases are blown into the space 6, where they mix with the cold air coming from the fan 55.

b) Granulation of a more or less thick one coming from the reaction vessels

Fertilizer mash

In this case, which concerns the production of mixed fertilizers, the water content is of the pulp usually more than 6 to 9%, which is necessary to achieve a satisfactory granulate is.

The device according to the invention then only allows the supply of the in the method according to the Sifting and grinding of the coarse material without adding any other fines, which come from a commercial product to be ground beforehand, as is the case with the usual production of NPK fertilizers is the case.

A preconcentration of the pulp is effected in the granulator 5 (FIG. 4) in the following way:

The fines to be circulated are fed through the chute 25 and passed through the line 28 at the same time to the pulp to be granulated, which in this way on an already existing Material layer hits.

The supply line 11 for hot gases is also set in motion by opening the line 13 after opening the valve 35 feeds through the line 33 connected to the heating chamber. As a result the particularly high performance of the gas inlet provided according to the invention is caused by the passage of the hot gases, the temperature of which can reach 400 ° C, strong evaporation in the interior of the layer emerges and results in a granulated mass, which in turn acts as a carrier mass for the continuously incoming mixture of fines and pulp is used.

The excess of the granulated product enters the dryer 6 and is exposed there the hot gases emerging from the granulate layer and those blown in by the fan 55 cold air a final drying.

c) Granulation of a mixture of a pulpy fertilizer mass and powdery solids

This example concerns the production of multi-nutrient fertilizers, which are obtained from a highly water-containing, mushy mass, which are mixed with different Solids (aggregates, phosphate fertilizers, etc.) to modify the final composition is moved. Depending on the water content of the mixture introduced into the granulator 5, compared with the optimal water content for granulation of 6 to 9%>, the above is followed Examples a) or b) before (adding water if the proportion of solid fertilizers predominates or recirculation of fines with appropriate control of the temperature of the injected Gases depending on the mean moisture content of the mass to avoid overheating).

d) fertilizer salts with a low melting point

The embodiment described below comes e.g. B. then used when the liquid Phase of fertilizer salt containing little water

melting consists. The granulation is brought about by mixing with colder, dry products. The fertilizer salts supplied through the chute 25 (FIG. 5) are blown in through the line 11 hot gases melted, while any necessary additional amounts of water through the line 27 can be fed. The slight, final drying is achieved by introducing gas into the Space 6 caused by channel 29. The distribution of the hot gases on the line 11 and the channel 29 is regulated by the valve 39 located in the bypass 38.

e) Induction of granulation
favoring chemical reactions

In certain cases you can cause a chemical reaction in the granulator, which under Changing the components of the fertilizer increases the temperature of the mass and thereby the granulation promotes. This can be B. in the granulation of superphosphate, powdered potassium chloride and mixtures containing liquid ammonium nitrate. This is because it reacts in the mixture the ammonium nitrate with the first two components mentioned under accelerated granulation.

First example: complex fertilizers,
which contain nitrogen and carbonate (Fig. 6)

The fertilizer is obtained starting from a pasty mass as in example b), but with the final reactions (treatment with ammonia and carbonic acid, if for digestion of rock phosphates more than 50% nitric acid used) give a very thick consistency, which a treatment in troughs does not more allowed.

With the methods customary up to now, the mass to be treated is then diluted with water in order to remove it To make it transportable and to be able to treat in a container. This added water must however, they are removed again during drying, which reduces the operating capacity of the device and a considerable consumption of calories. By the invention Device, the dilution described above is avoided.

The pulpy fertilizer mass to be treated is supplied with a viscosity that the supply line, z. B. the line 28, just allows. This unfinished mass is then used in the Granulator 5 with fed through the chute 25, circulated fines (return material) and with the product already contained in the room 5, which already has its final chemical composition has reached mixed.

In the case of the ammonia-carbonic acid treatment, gaseous ammonia is passed through line 36 and either through line 33 cold air or through line 38 hot air or a Mix the two one. The gases are mixed in line 13, and the gas mixture is then blown into the reaction mass through line 11.

The ammonia introduced, which hits a neutralized mass, is used for conversion of the excess calcium nitrate. At the same time, gaseous carbonic acid is passed through line 23 a, through the mouthpiece formed by the ramps 17 and 21 into the interior of the fertilizer mass entry. The resulting exothermic reaction causes the mass to dry out Granulated with little addition of fines. The scraper 16 prevents massaging of fertilizer. The excess of finished granulated fertilizer enters the dryer 6, where it absorbs hot gases and ίο additional cold air supplied through channel 29.

Second example: superphosphate (Fig. 7)

It is well known that freshly made superphosphate tends to be mixed with soluble salts, e.g. B.

Ammonium nitrate and potassium nitrate, to liquefy. For this reason the known method fines are circulated in order to ensure the granulation of the mass.

In contrast, when the mixture is ammoniated with gaseous ammonia, the the chemical reactions taking place and those caused by the heat of reaction released in the process A rise in the temperature of the mass results in a slight granulation of the end product, which in practically dry.

This result enables the device according to the invention, which allows the simultaneous introduction of gaseous ammonia and other constituents

3 "parts of the fertilizer allowed. The introduction of Ammonia also has the advantage that it is a valuable fertilizer component Ammonia nitrogen is bound.

In practice, a mixture of 8 to 10%> gaseous ammonia introduced through line 36 and fresh air supplied through line 33 is sent through line 11. The various solids (superphosphate and other salts or components of the fertilizer) as well as the circulating fines are continuously fed through the chute 25. The inventive device also allows the addition of other reactive substances, such. B. of sulfuric acid or phosphoric acid, to the mass. These acids are introduced together with the ammonia, which is converted into ammonium sulfate or phosphate. In this way, the fertilizer is enriched in nitrogen and, if phosphoric acid is used, in P ₂ O _5. These reactive acids are introduced into the granulator 5 through the line 27. The neutralization inside the mass with ammonia supplied through the gas line 11 increases the temperature and increases the evaporation of water, whereby the granulation and the final drying, which takes place in the space 6 as above, is facilitated. As already described, this drying takes place in the room 6 solely by a fresh air flow or, if necessary, by a mixture of fresh air with hot gases supplied in a suitable amount through the channel 29.

The above examples show that the device according to the invention is extremely adaptable and corresponds to the most diverse conditions which most known processes for the production of fertilizers require. The device described can be used in many ways and results in a considerable simplification of the individual process stages.

Claims (4)

PATENT CLAIMS: 1. Device for granulating and drying pulpy fertilizers of different types, consisting of two adjacent rotatable rooms, of which the front forms the granulator and has at least one longitudinal line for the supply of hot gases and the subsequent room is designed as a dryer, characterized in that the rooms ( 5) and (6) are enclosed by a single tubular, rotatable housing (1), the longitudinal line (13) through lines (12) extending perpendicularly therefrom feeds a gas inlet (11) which runs along the space (5) and which comes from a stationary Wall (15), whose edge (16) in contact with the housing (1) forms a scraper and whose other edge (17), which is at a certain distance from the housing, represents a ramp, via which the gases into the Inside the fertilizer mass in motion in the granulator are introduced. 2. Device according to claim 1, characterized in that the gas inlet (11) with a second feed for gaseous reactants is combined, which one the Space (14) adjacent space (19) forms and into the interior of the moving fertilizer mass joins. 3. Device according to claim 1, characterized in that the gas inlet (11) relative to the plane running vertically through the axis of the rotating housing (1) is offset in the sense of rotation is that the injected gases pass through the fertilizer mass to be granulated at one point, at which the layer formed by this mass is thickest. 4. Device according to claim 1, characterized in that it still has one in the granulator (5) leading chute (25) for feeding solids, lines (27, 28) of various kinds Diameter for feeding water, liquid reactants and pasty ones Substances as well as the supply of gases into the tubular housing enabling lines (13, 23). Considered publications:
French patent specification No. 864 503. For this purpose, 1 sheet of drawings ® 109 758/359 12.