EP4477761A1 - Dry pelletiser for dry granulation of molten material, in particular slag - Google Patents

Abstract

The invention relates to a dry granulator (10), wherein the dry granulator (10) has a housing (15) and an atomizer (20) arranged in the housing (15) with an atomizer element (55) mounted so as to be rotatable about a rotation axis (45), wherein the housing (15) has a first housing inner wall (70) with a first housing inner wall section (295) and a second housing inner wall section (305), wherein the atomizer element (55) has a wall (115) and a base (110), wherein the wall (115) has an edge (125) arranged axially spaced from the base (110) on an axial side facing away from the base (110), wherein the edge (125) is designed to vary between a first high point (185) and a first low point (190), wherein the edge (125) is closer to the first low point (190) is arranged at a greater distance from the bottom (110) than at the first high point (185), wherein the edge (125) is formed between and including the first high point (185) and the first low point (190), to spray molten material (35) from the atomizer element (55) in the direction of the first and second housing inner wall sections (295, 305) along different trajectories (291, 296).

Description

The invention relates to a dry granulator for dry granulation of molten material according to patent claim 1.

Out of CN 108 998 604 A A wet granulator for granulating slag and recovering waste heat is known. The wet granulator has a granulating unit with a rotating slag pan. The slag pan has a large number of channels arranged in a star shape, which extend from radially inside to radially outside. The slag hitting the slag pan is conveyed radially outwards through the channels and is essentially spun off radially outwards from the slag pan in one plane. The liquid slag flies radially outwards and falls downwards along a trajectory. The granulated slag is guided past an atomizer nozzle. The atomizer nozzle sprays atomized water onto the slag.

Out of JP 2003 342047 A A granulator with an essentially flat atomizer disk is known. The atomizer disk is made of a metallic material. Furthermore, the granulate is cooled using water.

The dry granulation of molten material is a technology under development to process molten material into a solid granulate. Molten material is, for example, molten metal or metallurgical slag, for example molten blast furnace slag - the process is then also called dry slag granulation DSG and is used, for example, in EP 2 747 920 B1 described. Dry in this context means that the molten material does not come into direct contact with liquid water during granulation - this is, for example, in contrast to conventional industrial processes for granulating blast furnace slag, in which the molten slag is introduced into a water stream. The granulator is a container delimited by a casing, which has a slag feed, a gas feed for process gas used for cooling and an exhaust line for heated process gas - for example air, also called process air. The molten material, for example molten metallurgical slag, is applied to an atomization unit located in the casing of the granulator; this is, for example, a rapidly rotating unit, known as rotary atomiser; something like this is used, for example, in EP 2 747 920 B1 shown. The accelerations or forces transmitted when the molten slag comes into contact with the rotary atomizer break the molten material into fine droplets and hurl them outwards. These fine, initially still molten droplets are cooled and solidify in the granulator, for example by the process gas and by impacting on - possibly cooled - surfaces of the granulator, for example the water-cooled casing of the granulator - as a result, solid particles are formed, here called granules, which are then removed from the granulator. According to a known method, liquid or partially solidified - i.e. partly liquid, partly solidified - droplets fall downwards in the granulator after leaving the rotary atomizer and then impacting on the casing of the granulator, for example into a fixed bed or a fluidized bed.

Conventional granulation technologies for dry granulation of molten material, such as liquid blast furnace slag, with rotary atomizers and use of an impact on the casing have a large diameter, since in order to avoid agglomeration of liquid and/or partially solidified drops and/or fully solidified particles during flight from the rotary atomizer to the casing or after impact on the casing, the distance of the casing - which is usually arranged rotationally symmetrically to the rotary atomizer and thus usually round in cross-section - must be chosen to be sufficiently large. A larger distance leads to a fanning out of the flow of drops or particles emanating from the rotary atomizer, so that they fly less close to one another or impact less closely. This reduces the risk of agglomeration during flight or impact. Agglomeration can occur during impact, for example, when completely or partially liquid particles are deformed upon impact and thus come into contact with neighboring impacting particles. However, increasing diameter leads to increasing space requirements, which is technologically and economically disadvantageous.

It is an object of the invention to provide an improved dry granulator.

This object is achieved by means of the features of patent claim 1. Advantageous embodiments are specified in the dependent claims.

It has been recognized that an improved dry granulator for dry granulation of molten material, particularly slag, can be provided by that it has a housing and an atomizer arranged in the housing with an atomizer element mounted so as to be rotatable about an axis of rotation. The housing has a first inner housing wall with a first inner housing wall section and a second inner housing wall section. The second inner housing wall section is arranged axially offset from the first inner housing wall section along the axis of rotation. The atomizer element has a wall and a base. The wall is designed to run all the way around in the circumferential direction with respect to the axis of rotation and extends radially on the outside adjacent to the base. On an axial side facing away from the base in the axial direction, the wall has an edge arranged at an axial distance from the base. The edge is designed to run at a different distance from the base between a first high point and a first low point. The edge is arranged closer to the base at the first low point than at the first high point. The edge is formed between the first high point and the first low point inclusive to spray molten material from the atomizer element in the direction of the first and second housing inner wall sections along different trajectories.

This design has the advantage that the molten granulate flies in a distributed manner in the direction of the first housing inner wall section, thus preventing the molten material from concentrating on the first housing inner wall in the region of a narrow band. In particular, adhesions of the molten material that is thrown radially outwards by the atomizer element can be avoided.

For example, at the first high point, the edge can spray a first part of the molten material from the atomizer element in the direction of the first housing wall inner section along a first trajectory. At the first low point, the edge can spray a second part of the molten material from the atomizer element in the direction of the second housing wall inner section along a second trajectory. The first trajectory can run axially offset from the second trajectory, thereby avoiding the concentration of the molten material on the first housing inner wall. The edge can also spray a further part of the molten material in the circumferential direction between the first high point and the first low point along a further trajectory that runs axially between the first trajectory and the second trajectory.

In a further embodiment, the dry granulator has a granulate storage with a fluidized bed. The granulate storage is arranged in the radial direction between the housing and the atomizer element. The fluidized bed has a first storage section and a second storage section. The first storage section is arranged radially offset on the inside to the second storage section. The first housing inner wall section is aligned obliquely to the axis of rotation in order to deflect the first part of the molten material hitting the first housing inner wall section in the direction of the first storage section. The second housing inner wall section is aligned obliquely to the axis of rotation in order to deflect the second part of the molten material hitting the second housing inner wall section in the direction of the second storage section. This design has the advantage that the first and second parts of the molten material fall into the granulate storage at a distance in the radial direction and are cooled there by the air flow flowing in via the fluidized bed and by the granulate already present in the granulate storage. In particular, the distribution of the molten material over the first and second housing inner wall sections can also prevent parts of the molten material, in particular several drops, from sticking together in the granulate storage, so that on the one hand the drops of the molten material in the granulate storage are quickly cooled to granulate and on the other hand the granulate has a substantially uniform granulate size.

In a further embodiment, the first inner housing wall is arranged at a wall angle of 30° to 60° inclusive, in particular 40° to 50° inclusive, to a plane of rotation inclined inwards to the axis of rotation. This design ensures that the molten material impacting on the first inner housing wall is well distributed in the granulate reservoir.

The wall of the atomizer element is divided in the circumferential direction relative to the axis of rotation into at least one first wall section and at least one second wall section. The second wall section adjoins the first wall section in the circumferential direction. The edge extends on the first wall section between the first high point and a first low point, which is arranged offset in the circumferential direction from the first high point. On the second wall section, the edge extends from the first low point in the circumferential direction away from the first wall section. The edge is designed to run obliquely inclined to a plane of rotation to the axis of rotation on the first wall section and on the second wall section. The edge is designed to spray the molten material from the atomizer element in the direction of the first housing inner wall. This design ensures that the atomizer element is essentially completely covered with the molten material on the top side, thereby preventing corrosion, in particular oxidation, of the atomizer element.

In a further embodiment, the atomizer element has a cone element. The cone element is arranged on the bottom on the side facing the wall and centered on the axis of rotation. The cone element extends away from the bottom along the axis of rotation. A tip of the cone element, which is arranged on a side of the cone element facing away from the bottom, projects beyond the first low point in the axial direction. The tip of the cone element is preferably arranged axially between the first high point and the first low point. This design ensures that the molten material striking the atomizer element does not accidentally spray off prematurely, thus ensuring an even distribution of the molten material on the atomizer element.

In a further embodiment, the atomizer element has a maximum radial total extension in the radial direction. The cone element has a first maximum radial extension at the bottom. A first ratio of the first maximum radial total extension to the maximum radial total extension is preferably 0.05 to 0.4 inclusive, in particular 0.1 to 0.25 inclusive. This design ensures that the material requirement for the cone element can be kept low and thus the manufacturing effort for producing the atomizer element can be kept low.

In a further embodiment, the atomizer element has a maximum total radial extent in the radial direction. The first high point has a first maximum distance from the bottom. A fourth ratio of the first maximum distance to the maximum total radial extent is in a range from 0.1 to 1 inclusive, preferably in a range from 0.15 to 0.3 inclusive.

In a further embodiment, the atomizer element has a maximum total radial extent in the radial direction, wherein the first low point has a first minimum distance from the ground. A fifth ratio of the first minimum distance to the maximum total radial extent is in a range of including 0.05 to 0.95, preferably in a range of 0.05 to 0.3 inclusive, in particular 0.08 to 0.2 inclusive. This ensures that the first low point is always located above the bottom. This ensures reliable coverage of the bottom by damming up the molten material through the wall. In particular, this avoids areas of the bottom being exposed and not covered by the molten material. This reduces unwanted oxidation of the atomizer element.

In a further embodiment, a sixth ratio of a difference between the first maximum distance and the first minimum distance to the maximum total radial extent is in a range from 0.05 to 0.1 inclusive. This configuration ensures that the material required to produce the atomizer element, which is preferably machined from a solid material, can be kept low.

In a further embodiment, the wall has a radially inner wall side and a radially outer circumferential side. The wall extends in the radial direction between the wall inner side and the outer circumferential side from the base in an axial direction towards the edge. Radially on the outside, the base has a second maximum radial extent. The wall has a minimum radial wall extent at the edge. A second ratio of the maximum total radial extent to the second maximum radial extent is 1.2 to 1.9 inclusive, in particular 1.4 to 1.7 inclusive. A third ratio of the maximum total radial extent to the minimum radial wall extent is 1.1 to 1.5 inclusive, in particular 1.2 to 1.35 inclusive. This design has the advantage that the wall is sufficiently wide so that in the event of oxidation of the outer peripheral side, which leads to material removal on the outer peripheral side and thus to a wall that becomes thinner from radially outside to radially inside with increasing operating time of the atomizer element, a long service life of the atomizer element is nevertheless ensured.

In order to minimize oxidation of the atomizer element on an outer peripheral side, the atomizer has a drive device with a receptacle and a protective gas channel. The atomizer element engages in the receptacle with a first section and is positively connected to the drive device for torque transmission. The atomizer element protrudes with a second section over the drive device, wherein the protective gas channel is guided in the drive device and one side opens into the holder. A protective gas can be guided through the protective gas channel to act on the second section of the atomizer element. The protective gas applies protective gas to the second section, which is not arranged in the holder. The protective gas can be nitrogen, for example. The protective gas reduces oxidation of the outer peripheral side, so that the service life of the atomizer element can be further increased.

It is particularly advantageous if the atomizer element is made predominantly, in particular at least 80 percent by mass, from a carbon-based material, preferably graphite. This design has the advantage that adhesions to the atomizer element by molten material can be avoided.

In a further embodiment, the edge has a predefined first number of high points and a predefined second number of low points. The first number is from 1 to 5 inclusive. Additionally or alternatively, the second number is from 1 to 5 inclusive. It is particularly advantageous if the edge has only two or three or four high points and/or two or three or four low points. The small number of high points and/or low points has the advantage that the edge has a lower inclination in the circumferential direction to the plane of rotation and it is therefore reliably ensured that the molten material between the high point and the low point is also thrown off over the edge between the high point and the low point. This ensures complete wetting of the atomizer element on the top side, so that oxidation of the atomizer element can be avoided, especially when graphite is used for the atomizer element.

It is particularly advantageous if the predefined first number of high points is less than or equal to 1 per 0.5 m circumference at the edge. Additionally or alternatively, the predefined second number of low points is also less than or equal to 1 per 0.5 m circumference at the edge. This design ensures that there is sufficient distance between a high point and a low point and thus in particular a large gradient of the edge in the circumferential direction to a plane of rotation between the high point and the low point is avoided.

FIG 1

eine schematische Schnittansicht durch einen Trockengranulator;

FIG 2

einen perspektivischen Ausschnitts des Trockengranulators ;

FIG 3

eine Schnittansicht entlang einer in FIG 2 gezeigten Schnittebene A-A durch den Zerstäuber; und

FIG 4

eine Schnittansicht entlang einer in FIG 2 gezeigten Schnittebene B-B durch den in FIG 1 gezeigten Zerstäuber.

The invention is explained in more detail below with reference to figures.

FIG 1

a schematic sectional view through a dry granulator;

FIG 2

a perspective view of the dry granulator;

FIG 3

a sectional view along a FIG 2 shown section plane AA through the atomizer; and

FIG 4

a sectional view along a FIG 2 shown cutting plane BB through the in FIG 1 atomizer shown.

FIG 1 shows a schematic sectional view through a dry granulator 10.

The dry granulator 10 is designed for the dry granulation of molten material 35, in particular molten slag from a metallurgical process, for example a blast furnace process. The dry granulator 10 has a housing 15, an atomizer 20, a granulate storage 25 and a feed 30 for feeding the molten material 35.

The housing 15 delimits a housing interior 40, wherein the housing 15 extends essentially in the circumferential direction around a rotation axis 45 of the atomizer 20. The feed line 30 is guided through the housing 15 and opens into the housing interior 40 on one side adjacent to the atomizer 20. In particular, the feed line 30 can be guided on the rotation axis 45 at least in sections and/or open into the housing interior 40 on the rotation axis 45.

The atomizer 20 extends along the rotation axis 45 and has a drive device 50, an atomizer element 55 and an atomizer housing 60. The atomizer element 55 is mounted so that it can rotate about the rotation axis 45 and is also connected to the drive device 50 in a rotationally fixed manner. The drive device 50 can have a drive motor (not shown) which is designed to drive the atomizer element 55 and to rotate about the rotation axis 45 during operation of the dry granulator 10. The drive motor can be arranged outside the housing interior 40 in order to prevent thermal overload of the drive motor. The drive motor can be connected to the drive motor in a torque-locking manner, preferably in a rotationally fixed manner, for example by means of a shaft 65. The shaft 65 can be mounted so that it can rotate in the atomizer housing 60.

In the embodiment, the atomizer element 55 has graphite as the predominant material. In this case, predominantly means that at least 50 percent by mass, preferably at least 80 percent by mass, is made of a carbon-based material. The carbon-based material can in particular be graphite.

The housing 15 has at least one first housing inner wall 70 and at least one second housing inner wall 75. In addition, the housing 15 can have a housing cover 80, preferably arranged on the top, wherein, for example, a discharge opening 85 is arranged in the housing cover 80. For example, the second housing wall 75 can be arranged adjacent to the first housing wall 70. Another design of the housing 15 is possible. In particular, for example, the discharge opening 85 can be arranged at a different position on the housing 15, for example on the first and/or second housing inner wall 70, 75.

The second housing inner wall 75 can extend essentially cylindrically around the rotation axis 45. The granulate storage 25 can be arranged in the radial direction between the second housing inner wall 75 and the atomizer housing 60. On the top side, FIG 1 the first housing inner wall 70 adjoins the second housing inner wall 75. At least the first housing inner wall 70, preferably the first and second housing inner walls 70, 75 are designed to be cooled. The first housing inner wall 70 is arranged inclined inwards in the direction of the axis of rotation 45. The first housing inner wall 70 can be designed to be essentially partially conical. The housing interior 40 tapers at the first housing inner wall 70 from the granulate storage 25 in the direction of the discharge opening 85 along the axis of rotation 45 in the axial direction.

Preferably, the first housing inner wall 70 is arranged at a wall angle δ to a rotation plane 76 perpendicular to the rotation axis 45. The wall angle δ can have a value of 30° to 60° inclusive, in particular 40° to 50° inclusive. By way of example, in FIG 1 the first housing inner wall 70 is arranged at the wall angle δ of 45° to the plane of rotation.

The first housing inner wall 70 is preferably smooth. In this case, smooth means that the first housing inner wall 70 essentially has no elevations (> 0.2 mm), in particular no kinks, compressions, bumps or the like.

The granulate storage device 25 is delimited, for example, by the second housing inner wall 75 arranged in the axial direction on the underside of the first housing inner wall 70.

The atomizer element 55 is arranged essentially at the level of the first housing inner wall 70. As a result, the first housing inner wall 70 and the atomizer element 55 have an axial overlap. In this case, an axial overlap is understood to mean that when two components are projected in a radial direction perpendicular to the axis of rotation 45 into a projection plane in which the axis of rotation 45 runs, the two components, for example the atomizer element 55 and the first housing inner wall 70, overlap.

The granulate storage device 25 has a fluidized bed 90 and a compressor 95. The compressor 95 is fluidically connected to the fluidized bed 90. The fluidized bed 90 is connected to the housing interior 40 on the underside. The fluidized bed 90 has a distributor base 100, wherein the distributor base 100 is fluidically connected to the compressor 95 on the outside. The distributor base 100 is arranged on the circumference between the atomizer housing 60 and the second housing inner wall 75.

FIG 2 shows a perspective section of the dry granulator 10.

The atomizer element 55 is bowl-shaped. The atomizer element 55 has at least one base 110 and a wall 115 that adjoins the base 110 on the radial outside. The wall 115 is arranged on the radial outside of the base 110 and extends away from the base 110 in the axial direction relative to the axis of rotation 45. Together, the base 110 and the wall 115 delimit an atomizer interior 120. The wall 115 is designed to completely encircle the axis of rotation 45 in the circumferential direction and encloses the base 110 on the radial outside. As a result, the atomizer interior 120 is completely enclosed in the radial direction.

The wall 115 has an edge 125 on the side facing away from the base 110. The edge 125 is arranged completely spaced apart from the base 110 in the axial direction. The edge 125 is formed completely circumferentially around the axis of rotation 45 on the wall 115. The wall 115 is blunt at the edge 125. Radially on the outside, the edge 125 abuts an outer peripheral side 135 of the atomizer element 55 at an outer edge 130. A first section 140 of the wall 115 adjoining the outer edge 130 can be formed cylindrically and running around the axis of rotation 45.

The edge 125 varies in an edge distance between the bottom 110 and the edge 125 between at least a first high point 185 and a first low point 190.

At the first high point 185, the edge distance is maximum, while at the first low point 190, the edge distance is minimum. Furthermore, the first low point 190 is arranged offset in the circumferential direction from the first high point 185. In the embodiment, the edge 125 additionally has a second high point 195 and a second low point 200, which are arranged offset from one another and from the first high point 185 and the first low point 190. The high point 185, 195 and the low point 190, 200 are each arranged offset in the circumferential direction around the axis of rotation. As a result, the edge 125 runs between the high point 185, 195 and the nearest low point 190, 200 at an angle in the circumferential direction to a rotation plane perpendicular to the axis of rotation 45.

It has proven to be particularly advantageous if a first number of high points 185, 195 and a second number of low points 190, 200 are limited. It is advantageous if the first number is from 1 to 5 inclusive and the second number is from 1 to 5 inclusive. It is even more advantageous if the edge 125 has only two or three or four high points 185, 195 and/or two or three or four low points 190, 200.

In the embodiment, the edge 125 has, for example, a jagged or wave-shaped course, wherein, for example, a turning point of the course of the edge 125 is arranged in the high point 185, 195 and/or in the low point 190, 200. In a further development of the FIG 2 It is also possible for the atomizer element 55 shown to be designed so that, instead of the jagged design of the edge 125, the edge 125 is designed to follow a mathematical function. For example, it is conceivable that the edge 125 is designed to be wave-shaped, in particular in the manner of a uniform wave. For example, the edge 125 could also be designed to be sinusoidal. It is essential in the design of the edge 125 that jumps, in particular flanks extending in the axial direction parallel to the axis of rotation 45, are dispensed with in the edge 125.

Between the high points 185, 195 and the low points 190, 200, the wall 115 is divided into wall sections 155, 160, 205, 210. A first wall section 155 extends, for example, between the first high point 185 and the first low point 190. In the first wall section 155, the edge 125 is designed to run continuously. In particular, the edge 125 on the first wall section 155 can have a constant slope. In the embodiment, the edge 125 in the first wall section 155 slopes down from the first high point 185, which is arranged further away from the floor 110 than the first low point 190, in the direction of the first low point 190.

A second wall section 160 directly adjoins the first wall section 155 in the circumferential direction. The second wall section 160 extends in the circumferential direction between the first low point 190 and the second high point 195, which is closest in the circumferential direction and is arranged on a side facing away from the first high point 185. The second wall section 160 is designed to be continuous. In the second wall section 160, the edge 125 has a constant slope. In the second wall section 160, the edge 125 is designed to be continuous and increases continuously.

In the circumferential direction, a third wall section 205 adjoins the second high point 195. The third wall section 205 extends in the circumferential direction between the second high point 195 and the second low point 200 arranged in the circumferential direction on the side facing away from the first low point 190. The third wall section 205 can be designed essentially identically to the first wall section 155. In the circumferential direction, the fourth wall section 210 adjoins the second low point 200, with the fourth wall section 210 extending in the circumferential direction between the second low point 200 and the first high point 185. The fourth wall section 210 is thus arranged, for example, in the circumferential direction between the third wall section 205 and the first wall section 155. The fourth wall section 210 can be designed identically to the second wall section 160. At the first high point 185, the fourth wall section 210 abuts the first wall section 155 on the side facing away from the third wall section 205. The edge 125 is also continuously formed in the third wall section 205 and the fourth wall section 210.

FIG 3 shows a sectional view along a FIG 2 shown section plane AA through the atomizer 20.

For example, the cutting plane A-A extends through the two low points 190, 200.

In addition, the atomizer element 55 can have a cone element 215. The cone element 215 is arranged at a fixed end 220 on the base 110 and extends from a bottom 145 of the atomizer element 55. The cone element 215 is arranged centered on the axis of rotation 45 and extends away from the base 110. The bottom 145 is arranged on an axial side facing away from the base with respect to the axis of rotation 45. The cone element 215 tapers from the fixed end 220 towards a tip 225. The tip 225 is arranged in the axial direction with respect to the axis of rotation 45 between the first low point 190 and the first high point 185.

In other words, the tip 225 projects beyond the edge 125 at least at the first low point 190 and/or the second low point 200. Furthermore, the tip 225 is preferably projected beyond at least the edge 125 at the first high point 185 and/or the second high point 195.

The mouth 230 of the feed 30 is arranged in the axial direction opposite the tip 225. The mouth 230 is also preferably arranged centered to the axis of rotation 45, wherein the feed 30 is preferably arranged centered along the axis of rotation 45 at least in the section adjacent to the mouth 230.

The atomizer element 55 has a maximum radial total extension R in the radial direction. The maximum radial total extension R relates, for example, to the outer edge 130 at the edge 125. The outer peripheral side 135 is, for example, cylindrical in the embodiment, extending around the axis of rotation 45, so that the maximum radial total extension R also relates to the outer peripheral side 135. At the fixed end 220, the cone element 215 has a first maximum radial extension d1. Preferably, a first ratio d1/ of the first radial total extension d1 to that of the maximum radial total extension R is 0.05 to 0.4 inclusive, in particular 0.1 to 0.25 inclusive, particularly advantageously 0.15 to 0.2 inclusive.

Radially on the outside of the cone element 215, the base 110 has a base surface 235 which is designed to be flat, for example. The base surface 235 extends, for example, perpendicular to the axis of rotation 45. In the embodiment with the cone element 215, the base surface 235 is designed to run in a ring around the cone element 215. The cone element 215 is rounded at a first transition 236 between the base surface 235 and the cone element 215 in order to ensure a smooth and continuous transition between the cone element 215 and the base surface 235. This also prevents the molten material 35 from sticking.

The wall 115 adjoins the base surface 235 radially on the outside. The base 110 has a second maximum radial extension d2 on the base surface 235, wherein a second ratio R/d2 of the maximum total radial extension R to the second maximum radial extension is preferably 1.2 to 1.9 inclusive, in particular 1.4 to 1.7 inclusive. The wall 115 is rounded at a second transition 237 between the base surface 235 and the wall 115 in order to achieve a smooth and continuous transition. Adhesion of the molten material 35. The second maximum extension d2 can be determined, for example, at an intersection point of a straight line that runs tangentially to the wall 115 and a plane in which the bottom surface 235 runs.

The wall 115 is wider in the radial direction on the side facing the base 110 than at the edge 125. In other words, the wall 115 tapers in the axial direction from the base 110 to the edge 125. At the edge 125, the wall 115 has a minimum radial wall extension w2 that is greater than the second maximum radial extension d2. At a third transition 238 between the wall inner side 240 and the edge 125, the wall 115 is rounded so that adhesion of the molten material 35 is ensured by a smooth and continuous transition. At the third transition 238, the edge 125 has the minimum wall extension w2. A third ratio R/w2 of the maximum total radial extension R to the minimum radial wall extension w2 is preferably 1.1 to 1.5 inclusive, in particular 1.2 to 1.35 inclusive.

The wall 115 primarily forms the bowl-shaped configuration of the atomizer element 55. The wall 115 has the inner wall side 240 arranged radially on the inside, the inner wall side 240 being curved and the second transition 237 between the bottom surface 235 and the inner wall side 240 being continuous. The inner wall side 240 runs, for example, at an angle to the bottom surface 235, which runs, for example, perpendicular to the axis of rotation 45. The inner wall side 240 can be arranged, for example, at an angle to the bottom surface 235. The first angle α is preferably 15° to 60° inclusive, in particular 30° to 40° inclusive, particularly advantageously 35°.

The edge 125 is arranged radially on the outside and on the side of the wall 115 facing away from the base 110. The edge 125 is preferably arranged at an angle at a second angle β to the plane of rotation 76 and the base surface 235. The edge 125 is preferably arranged at an angle inwardly towards the axis of rotation 45, so that as the distance of the edge 125 from the axis of rotation 45 increases, a third maximum distance l1 of the edge 125 from the base surface 235 increases.

At the first high point 185, the edge 125 has a first maximum distance H1 from the floor 110. At the first low point 190, the edge 125 has a first minimum Distance G1 from the floor 110 in the axial direction. At the second high point 195, the edge 125 has a second maximum distance from the floor 110. At the second low point 200, the edge has a second minimum distance from the floor 110 in the axial direction. In the embodiment, the first minimum distance G1 and the second minimum distance are, for example, identical. They can also be different. In the embodiment, the first maximum distance H1 and the second maximum distance are, for example, identical. They can also be different.

At the first low point 190, the edge 125 is thus offset in the direction of the base 110. The first minimum distance G1 is selected such that the first wall section 155 also projects beyond the base 110 at the first low point 190. It is particularly advantageous if a fourth ratio H1/R of the first maximum distance H1 to the maximum total radial extent R is greater than 0.1 up to and including 1 and preferably lies in a range from 0.1 up to and including 0.3.

It is particularly advantageous if a fifth ratio G1/R of the first minimum distance G1 to the maximum total radial extent R is greater than 0.05 to 0.95 inclusive and preferably lies in a range from 0.05 to 0.3 inclusive, in particular from 0.08 to 0.2 inclusive.

Furthermore, a sixth ratio (H1-G1)/R from a difference between the first maximum distance H1 and the first minimum distance G1 and the maximum total radial extent R can be greater than or equal to 0.05 and preferably in a range from 0.05 to 0.1 inclusive.

Furthermore, it is advantageous if, as a further condition for the first number of high points 185, 195, the first number of high points is less than or equal to 1 per 0.5 m circumference. Furthermore, it is advantageous if, as an additional condition for the second number of low points 190, 200, the second number is less than or equal to 1 per 0.5 m circumference. The circumference is here related to the outer edge 130 of the edge 125.

The second angle β is smaller than the first angle α. In particular, the second angle β can be 0° to 45°, in particular 3° to 12°. While an inner edge 245 at the third transition 238 of the inner wall 240 to the edge 125 is continuous and rounded, in the embodiment the outer edge 130 is sharp-edged. The sharp-edged design of the outer edge 130 serves to ensure reliable spraying of the molten material 35 from the atomizer element 55.

FIG 4 shows a sectional view along a FIG 2 shown cutting plane BB through the in FIG 1 shown atomizer 20.

The section plane B-B extends, for example, through the two high points 185, 195.

In the axial direction, a second section 150 adjoins the first section 140 on the side facing the underside 145 of the atomizer element 55, wherein a part of the second section 150 can be elliptical, for example. Another design of the second section 150 is also conceivable. In particular, the part of the second section 150 can be designed in its geometric design as a connecting profile for the positive connection of the atomizer element 55 to the shaft 65.

The drive device 50 has a carrier unit 250 in addition to the shaft 65. The carrier unit 250 is connected to the shaft 65 in a torque-locking manner. The carrier unit 250 serves to carry the atomizer element 55 and to fasten it in the housing interior 40. The carrier unit 250 has a receptacle 255, wherein the atomizer element 55 is arranged in sections in the receptacle 255. The atomizer element 55 protrudes with the first partial section 140 from the receptacle 255, while the second partial section 150 engages in the receptacle 255. In the receptacle 255, the atomizer element 55 is positively connected to the carrier unit 250.

A torque for driving the atomizer element 55 is preferably exchanged between the drive motor and the atomizer element 55 via the shaft 65 and the carrier unit 250.

In the embodiment, the carrier unit 250 has a carrier ring 266. The first carrier ring 266 is coupled directly or indirectly to the shaft 65 in a torque-locking manner, in particular in a rotationally fixed manner. The first carrier ring 266 essentially delimits the receptacle 255. The first carrier ring 266 is preferably connected in a form-fitting manner to the outer peripheral side 135 of the atomizer element 55. To form the form-fitting connection between the outer peripheral side 135 of the atomizer element 55 and the first carrier ring 266, the first carrier ring 266 can, for example, have a polygon-shaped profile on an inner peripheral side 280, wherein the outer peripheral side 135 is designed to correspond to the polygon-shaped profile on the inner peripheral side 280 of the first carrier ring 266. On the underside, the atomizer element 55 can be mounted on the Carrier unit 250 rests in the receptacle 255, wherein an axial position of the atomizer element 55 in the receptacle 255 is secured, for example, by a dead weight of the atomizer element 55.

In addition, the carrier unit 250 can be designed to be cooled. A cooling medium can be guided to the carrier unit 250 via the shaft 65, which has, for example, an inlet and a return channel, in order to cool the atomizer element 55 on the underside.

A protective gas channel 285 is arranged in the carrier ring 266. The protective gas channel 285 is guided at an angle from the radial outside to the radial inside. The protective gas channel 285 opens into the receptacle 255 on the side facing the first section 140. A protective gas 290, for example nitrogen, can be blown into the end of the receptacle 255 via the protective gas channel 285 using additional means (not shown). It is particularly advantageous if the protective gas 290 is blown into the receptacle 255 in a circulating manner, i.e. at a circumferential speed, in the direction of the first section 140. Because the protective gas channel 285 is designed at an angle inwards in the direction of the first section 140, the protective gas 290 is blown onto the first section 140, which is arranged outside the receptacle 255. This can reduce oxidation of the atomizer element 55, which is essentially made of graphite.

Below are the Figures 1 to 4 explained together.

When the dry granulator 10 is in operation, the drive motor of the drive device 50 drives the atomizer element 55 via the shaft 65 and the carrier unit 250. The atomizer element 55 can rotate about the axis of rotation 45 at a speed of approximately 500 to 1500 revolutions per minute. Furthermore, molten material 35, in particular liquid slag, is introduced into the housing 15 via the feed 30. The molten material 35 exits the feed 30 at the mouth 230 and flows downwards along the axis of rotation 45. The molten material 35 comes into contact with the atomizer element 55 at the cone element 215. The molten material 35 is diverted outwards from its movement along the axis of rotation 45 by the cone element 215. The molten material 35 covers the cone element 215. The molten material 35 flows in the axial direction along the cone element 215 in the direction of the bottom 110. The molten material 35 is also guided radially outwards towards the bottom surface 235 under the influence of centrifugal force on the cone element 215.

At the bottom surface 235, the molten material 35 flows radially outwards and is strongly accelerated in the radial and circumferential directions by the rotation of the atomizer element 55. Radially outwards, the molten material 35 hits the wall 115. In the process, the molten material 35 is further accelerated in the radial outward and circumferential directions. Furthermore, the molten material 35 is guided along the inner wall side 240 in the axial direction away from the bottom 110 in the direction of the edge 125. The continuous second transition 237 between the bottom surface 235 and the inner wall side 240 has the advantage that accumulations of the molten material 35 are avoided during acceleration radially outwards. Furthermore, the cone element 215 ensures reliable coverage of the base surface 235 and the inner wall 240. This prevents oxidation of the atomizer element 55 with atmospheric oxygen and premature departure of the slag from the turntable. The molten material 35 flows radially outwards and in an axial direction away from the base 110. The molten material 35 flows around the inner edge 245 and remains in contact with the atomizer element 55 through the small second angle β. The rounded third transition 238 prevents the molten material 35 from accidentally spraying off the inner edge 245.

The molten material 35 flows around the inner edge 245 and flows radially outward along the edge 125. The molten material 35 flows to the outer edge 130, wherein the molten material 35 is sprayed off at the outer edge 130.

At the first high point 185 and at the second high point 195, for example, a first part of the molten material 35 leaves the atomizer element 55 on a first trajectory 291 (cf. FIG 1 ). The first drop of the first part of the molten material 35 flies along the first trajectory 291 in the direction of a first housing inner wall section 295 of the first housing inner wall 70. In the liquid state, the first drop hits the first housing inner wall section 295. Due to the obliquely inclined arrangement of the first housing inner wall 70, the first drop of the molten material 35 bounces off the first housing inner wall section 295 and is deflected substantially downwards along the axis of rotation 45 in the direction of a first storage section 300 of the granulate storage 25.

Due to the axially offset arrangement of the first high point 185 and the second high point 195 to the first low point 190 and the second low point 200, a second part of the molten material 35 is deposited at the first and second low points 190, 200 are sprayed off the atomizer element 55 on a second trajectory 296 at the outer edge 130. A second drop of the second part flies along the second trajectory 296, which is arranged axially offset from the first trajectory 291, in the direction of the first housing inner wall 70. The second drop strikes the first housing inner wall 70 in a second housing inner wall section 305, which is arranged lower along the axis of rotation 45 and thus on the side of the first housing inner wall facing the granulate storage 25. The second drop bounces off the second housing inner wall section 305, which is arranged radially further out than the first housing inner wall section 295 due to the arrangement on the side facing the granulate storage 25. The second storage section 310 of the granulate storage 25 is arranged radially on the outside of the first storage section 300. The second drop flies into the second storage section 310.

In the first storage section 300 and the second storage section 310, the first drop and the second drop are cooled by the process air blown in by the compressor 95 in the fluidized bed 90 to such an extent that the first drop solidifies in the first storage section 300 and the second drop solidifies at a distance from the first drop in the second storage section 310.

Of course, molten material 35 is also sprayed off at the edge 125 between the high point 185, 195 and the low point 190, 200. The additional drops sprayed between the high point 185, 195 and the low point 190, 200 each fly on additional trajectories that are fanned out between the first trajectory 291 and the second trajectory 296 in the direction of the first housing inner wall 70. Due to the design of the atomizer element 55, a jet of drops that forms on the atomizer element 55 from the molten material 35 as a result of the spraying is fanned out and hits the first housing inner wall 70 in a fanned out manner between the first and second trajectories 291, 296. The fanned out design has the advantage that the drops of the molten material 35 can be prevented from adhering to the first housing inner wall 70 and thus the detachment of conglomerated drops of molten material 35 on the first housing inner wall 70 can be easily avoided.

Furthermore, the fanning out of the molten material 35 on the atomizer element 55 has the further advantage that the probability that drops that enter the granulate reservoir 25 in a liquid state do not meet further drops that have not yet solidified, and thus the adhesion of several drops of molten material 35 is avoided. This ensures a high quality and in particular a reliable grain size of the molten material 35 solidified in the granulate storage 25 to form granules.

Furthermore, a reliable cooling of the drops of molten material 35 arriving in the granulate storage 25 and a reliable solidification of the drops of molten material 35 in the granulate in the fluidized bed 90 of the granulate storage 25 can be ensured.

Furthermore, the molten droplets release large amounts of heat into the process air when they cool down with the process air. The process air can be discharged from the housing interior 40 via the discharge opening 85 and used, for example, to flow through a heat exchanger in order to generate steam. This design has the advantage that the dry granulator 10 shown in the figures not only ensures high process reliability and also ensures high quality of the molten material 35 solidified into granules and a corresponding grain size, but also that the heat contained in the molten material 35 can be further utilized.

Furthermore, the use of water for cooling the molten material 35 can be dispensed with, so that environmental pollution with the dry granulator 10 shown in the figures is reduced.

In order to ensure a long service life of the atomizer element 55, which is preferably made of graphite, the atomizer element 55 is essentially completely wetted by the molten material 35 on the side facing the mouth 230. This ensures that the atomizer element 55, which is heated to 1500 °C, is protected against oxidation. In order to counteract oxidation of the graphite occurring on the outer peripheral side 135 in the region of the first section 140, the protective gas 290 can be blown onto the first section 140 by means of the protective gas channel 285, thus avoiding or reducing oxidation of the atomizer element 55 on the outer peripheral side 135.

If oxidation of the first section 140 on the outer peripheral side 135 does occur, the minimal radial wall extension w2 ensures a long service life. Furthermore, reliable spraying behavior is ensured by the blunt wall 115 on the edge 125, even if oxidation occurs on the first section 140 on the outer peripheral side 135 should have corroded the wall 115 due to oxidation.

list of reference symbols

10

dry granulator

15

Housing

20

atomizer

25

granulate storage

30

feeding

35

molten material

40

housing interior

45

axis of rotation

50

drive device

55

atomizer element

60

atomizer housing

65

Wave

70

first inner housing wall

75

second inner housing wall

76

plane of rotation

80

housing cover

85

discharge opening

90

fluidized bed

95

compressor

100

distributor floor

105

storage volume

110

Floor

115

wall

120

atomizer interior

125

edge

130

outer edge

135

outer peripheral side

140

first section

145

bottom

150

second section

155

first wall section

160

second wall section

165

first angle segment

170

second angle segment

175

first edge section

180

second edge section

185

first high point

190

first low point

195

second high point

200

second low point

205

third wall section

210

fourth wall section

215

cone element

220

fixed end

225

Great

230

mouth

235

floor area

236

first transition

240

inside of the wall

245

inner edge

250

carrier unit

255

Recording

266

first carrier ring

280

inner peripheral side

285

protective gas channel

290

protective gas

295

first housing inner wall section

300

first memory section

305

second housing inner wall section

310

second storage section

d1

first maximum radial extension

d2

second maximum radial extension

d3

third maximum radial extension

G1

first minimum distance

H

edge distance

H 1

first maximum distance

11

third maximum distance

R

maximum total radial extension

w2

minimal radial wall extension

α

first angle

β

second angle

δ

wall bracket

Claims (14)

Dry granulator (10) for dry granulation of molten material (35), in particular slag from a metallurgical process, - wherein the dry granulator (10) has a housing (15) and an atomizer (20) arranged in the housing (15) with an atomizer element (55) mounted rotatably about a rotation axis (45), - wherein the housing (15) has a first housing inner wall (70) with a first housing inner wall section (295) and a second housing inner wall section (305) which is arranged axially offset from the first housing inner wall section (295) along the axis of rotation (45), - wherein the atomizer element (55) has a wall (115) and a bottom (110), - wherein the wall (115) is designed to be circumferential in the circumferential direction relative to the axis of rotation (45) and adjoins the base (110) radially on the outside and has an edge (125) arranged axially spaced from the base (110) on an axial side facing away from the base (110), - wherein the edge (125) is formed between a first high point (185) and a first low point (190) varying at different distances from the bottom (110), - wherein the edge (125) is arranged closer to the bottom (110) at the first low point (190) than at the first high point (185), - wherein the edge (125) between the first high point (185) and the first low point (190) is designed to spray molten material (35) from the atomizer element (55) in the direction of the first and second housing inner wall sections (295, 305) along different trajectories (291, 296). Dry granulator (10) according to claim 1, - comprising a granulate storage (25) with a fluidized bed (90), - wherein the granulate reservoir (25) is arranged in the radial direction between the housing (15) and the atomizer element (55), - wherein the fluidized bed (90) has a first storage section (300) and a second storage section (310), - wherein the first storage section (300) is arranged radially inwardly offset from the second storage section (310), - wherein the first housing inner wall section (295) is aligned obliquely to the axis of rotation (45) in order to deflect a first part of the molten material (35) striking the first housing inner wall section (295) in the direction of the first storage section (300), - wherein the second housing inner wall section (305) is aligned obliquely to the axis of rotation (45) in order to deflect a second part of the molten material (35) striking the second housing inner wall section (305) in the direction of the second storage section (310). Dry granulator (10) according to claim 2, - wherein the first housing inner wall (70) is arranged at a wall angle of 30° to 60° inclusive, in particular 40° to 50° inclusive, to a rotation plane (76) to the rotation axis (45) inclined obliquely inwards in the direction of the rotation axis (45). Dry granulator (10) according to one of the preceding claims, - wherein the wall (115) is divided in the circumferential direction relative to the axis of rotation (45) into at least one first wall section (155) and at least one second wall section (160), - wherein the second wall section (160) adjoins the first wall section (155) in the circumferential direction, - wherein the edge (125) on the first wall section (155) extends between the first high point (185) and a first low point (190) which is arranged offset in the circumferential direction from the first high point (185), - wherein the edge (125) on the second wall section (160) extends from the first low point (190) in the circumferential direction away from the first wall section (155), - wherein the edge (125) on the first wall section (155) and on the second wall section (160) is inclined in the circumferential direction to a plane of rotation (76) to the axis of rotation (45), - wherein the edge (125) is formed both on the first wall section (155) and on the second wall section (160) to spray the molten material (35) from the atomizer element (55) in the direction of the first housing inner wall (70). Dry granulator (10) according to one of the preceding claims, - wherein the atomizer element (55) has a cone element (215), - wherein the conical element (215) is arranged on the bottom (110) on the side facing the wall (115) and centered on the axis of rotation (45), - wherein the cone element (215) extends along the axis of rotation (45) away from the base (110), - wherein a tip (225) of the conical element (215), which is arranged on a side of the conical element (215) facing away from the bottom (110), projects beyond the first low point (190) in the axial direction, - wherein preferably the tip (225) of the cone element (215) is arranged axially between the first high point (185) and the first low point (190). Dry granulator (10) according to claim 5, - wherein the atomizer element (55) has a maximum total radial extension (R) in the radial direction, - wherein the conical element (215) has a first maximum radial extension (d1) at the bottom (110), - wherein a first ratio (d1/R) of the first maximum total radial extent (d1) to the maximum total radial extent (R) is preferably 0.05 to 0.4 inclusive, in particular 0.1 to 0.25 inclusive. Dry granulator (10) according to one of the preceding claims, - wherein the atomizer element (55) has a maximum total radial extension (R) in the radial direction, - wherein the first high point (185) has a first maximum distance (H1) from the ground (110), - wherein a fourth ratio (H1/R) of the first maximum distance (H1) to the maximum total radial extent (R) is in a range from 0.1 to 1 inclusive, preferably in a range from 0.1 to 0.3 inclusive. Dry granulator (10) according to one of the preceding claims, - wherein the atomizer element (55) has a maximum total radial extension (R) in the radial direction, - wherein the first low point (190) has a first minimum distance (G1) to the ground (110), - wherein a fifth ratio (G1/R) of the first minimum distance (G1) to the maximum total radial extent (R) is in a range from inclusive 0.05 to 0.95, preferably in a range of 0.05 to 0.3 inclusive, in particular 0.08 to 0.2 inclusive. Dry granulator (10) according to claim 8, - wherein a sixth ratio ((H1-G1)/R) of a difference between the first maximum distance (H1) and the first minimum distance (G1) and the maximum total radial extent (R) is in a range from 0.05 to 0.1 inclusive. Dry granulator (10) according to one of the preceding claims, - wherein the wall (115) has a radially inner wall inner side (240) and a radially outer peripheral side (135), - wherein the wall (115) is tapered in the radial direction between the inner wall side and the outer peripheral side (135) from the bottom (110) in the axial direction towards the edge (125), - wherein the base (110) has a second maximum radial extension (d2) on the radially outer side, - wherein the wall (115) has a minimum radial wall extension (w2) at the edge (125), - wherein a second ratio (R/d2) of the maximum total radial extent (R) to the second maximum radial extent (d2) is 1.2 to 1.9 inclusive, in particular 1.4 to 1.7 inclusive, - wherein a third ratio (R/w2) of the maximum total radial extension (R) to the minimum radial wall extension (w2) is 1.1 to 1.5 inclusive, in particular 1.2 to 1.35 inclusive. Dry granulator (10) according to one of the preceding claims, - wherein the atomizer (20) has a drive device (50) with a receptacle (255) and a protective gas channel (285), - wherein the atomizer element (55) engages with a first portion (140) in the receptacle (255) and is positively connected to the drive device (50) for torque transmission, - wherein the atomizer element (55) projects with a second section (150) beyond the drive device (50), - wherein the protective gas channel (285) is guided in the drive device (50) and opens into the receptacle (255) on one side, - wherein a protective gas (290) can be guided via the protective gas channel (285) to act on the second partial section (150) of the atomizer element (55). Dry granulator (10) according to one of the preceding claims, - wherein the atomizer element (55) is predominantly made, in particular at least 80 percent by mass, of a carbon-based material, preferably graphite. Dry granulator (10) according to one of the preceding claims, - wherein the edge (125) has a predefined first number of high points (185, 195) and a predefined second number of low points (190, 200), - where the first number is from 1 to 5 inclusive and/or the second number is from 1 to 5 inclusive. - wherein the edge (125) advantageously has exclusively two or three or four high points (185, 195) and/or two or three or four low points (190, 200). Dry granulator (10) according to one of the preceding claims, - where the predefined first number of high points (185, 195) is less than or equal to 1 per 0.5 m circumference at the edge (125), - and/or - wherein the predefined second number of low points (190, 200) is less than or equal to 1 per 0.5 m circumference at the edge (125).

Images