TW202337968A - Drying device for polymer granules - Google Patents

Abstract

The present invention relates to a trickle device 10 for a particulate material, wherein the trickle device 10 has an input region 20, a centre region 30 and an output region 40, wherein the input region 20 is disposed above and directly adjacent to the centre region 30, wherein the centre region 30 is disposed above and directly adjacent to the output region 40, wherein the trickle device 10 has an outer wall 50, wherein the centre region 30 has a first axis of symmetry 60, wherein at least in the centre region 30 a first body 70 is disposed, wherein the first body 70 extends over the entire length of the centre region 30, wherein the first body 70 has a second axis of symmetry 60, wherein the first axis of symmetry 60 and the second axis of symmetry 60 are coaxial, wherein the distance between the outer wall (50) and the first body (70) in the centre region is constant, wherein at least one first fluid feed 80 and an optional second fluid feed 90 are disposed in the centre region 30, wherein the first fluid feed 80 and the optional second fluid feed 90 are designed for the areal supply of fluid over the cross section of the trickle device 10.

Description

Drying device for polymer particles

Field of invention

The present invention relates to an apparatus for drying polymer particles.

Background of the invention

Corresponding devices are known from the prior art. In short, particles are supplied from above, while gases pass through in counter-current flow from below.

EP 2 671 902 B1 discloses polyamide conditioning.

DE 39 23 061 C1 discloses a method and device for drying and thermal conditioning of polyamide particles.

WO 2009/153 340A1 discloses a continuous method for multi-stage drying and post-condensation of polyamide particles.

US 2009/0163694 A1 discloses a continuous drying method for high-efficiency amine formaldehyde resin aqueous solution.

However, it has emerged that in conventional plants a particularly rapid central flow of particles occurs in the center of the device. This effect becomes more pronounced at larger radii, and so the effect becomes stronger as the size of the device increases. On the contrary, the gas flow in this region is slow. This results in differences in granular particle residence time and thus in drying.

The product uniformity of particles (also called fragments) is largely determined by the residence time distribution of the particles and the residence time distribution of the gas within the device. The gas here can be delivered counter-currently or co-currently with the particles. Especially when the inner diameter of the equipment is relatively large, with a diameter exceeding 2m, the conventional structure according to the current design is accompanied by zones with slower flow passages and zones with faster flow passages. Therefore, for example, polyamide production capacity exceeding 100t/d is only available using two equipment operating in parallel. However, it is desirable to be able to implement a polyamide drying stage in one unit with a throughput of, for example, 200 t/d or more.

It is an object of the present invention to provide a flow profile for gases and particles that achieves particularly uniform drying.

This object is achieved by a trickle device having the characteristics specified in claim 1. Advantageous developments are apparent from the accompanying claims, the description below and the drawings.

According to an embodiment of the present invention, a trickling device (10) for particulate materials is specifically proposed, wherein the trickling device (10) has an input area (20), a central area (30) and an output area. (40), wherein the input area (20) is arranged above the central area (30) and directly adjacent to the central area (30), wherein the central area (30) is arranged above the output area (40) and directly adjacent to the output area (40) ) adjacent to each other, wherein the trickle device (10) has an outer wall (50), wherein the central area (30) has a first axis of symmetry (60), and wherein at least a first body is provided in the central area (30) (70), wherein the first body (70) extends over the entire length of the central region (30), wherein the first body (70) has a second axis of symmetry (60), wherein the first axis of symmetry (60) ) is identical to the second axis of symmetry (60), wherein the distance between the outer wall (50) and the first body (70) is constant in the central zone (30) or in the output zone ( 40) is provided with at least a first fluid feed (80), wherein the first fluid feed (80) is designed to supply fluid in a cross-sectional area of the trickle device (10).

Detailed description of preferred embodiments The drip flow device of the present invention is suitable for use with particulate materials. These types of trickle units are used as drying units, condensing units, post-condensing units, conditioning units or as silo units. Particularly preferred particulate materials are particulate polymers, more particularly polyamide, polyethylene terephthalate, polylactide and copolymers thereof. In particular, trickle flow devices are used for the processing of these polymers following their production. The drip flow device has an input area, a central area and an output area.

In the input zone particulate material is fed and then trickles through the central zone before landing at the bottom of the output zone where it can be removed from the trickle device. The outlet for particulate material is preferably located in the center of the bottom end. Therefore, the input zone is placed above and directly adjacent to the central zone, and the central zone is set above and directly adjacent to the output zone.

The trickle device has an outer wall. An outer wall in the sense of the present invention is understood to be the outer boundary of the interior. The outer wall may further have support structures, insulation layers, heat transfer areas or the like on the outside, which however, in the terms of the present invention, are not part of the outer wall. The central area has a first axis of symmetry. For the tubular outer wall example, the central axis of the cylinder is the axis of symmetry. It spreads vertically across this central area in a longitudinal direction. Likewise, the same is true for polygonal cross-sections, for example square, hexagonal or octagonal cross-sections. At least a first body is provided in the central area. The first body extends the entire length of the central region from top to bottom. The first body also has a second axis of symmetry. Accordingly, the statements made regarding the cross-section of the outer wall and the axis of symmetry are valid here. The first axis of symmetry and the second axis of symmetry are the same, so they are located exactly on the other axis. For example, when they both have circular cross-sections, the center points of the two circular cross-sections are located at the same position. The distance between the outer wall and the first body is constant in the central area. This means, for example, that the first body may taper; in this case the taper also occurs parallel in the outer wall, so that a constant distance means that there is no adverse effect on the residence time distribution. At least one first fluid feed and optionally a second fluid feed are provided in the central zone or in the output zone. Deployment in the output area preferably occurs as far away as possible directly below the center area. These fluid feeds serve to supply fluid, more specifically gas, into the interior. This first makes it possible to fluidize particulate materials. However, it is preferred not to cause fluidization, but only drying. Secondly, in the case of drying, drying gas (eg nitrogen) or drying air is supplied to dry the particulate material. The first fluid feed and the optional second fluid feed are designed to supply fluid over a cross-sectional area of the trickle device. In the sense of the present invention, a zone supply means a supply of fluid in a cross section, in particular perpendicular or obliquely to the axis of symmetry, with a plurality of supply points along the radial section.

An example of a regional supply of fluid would be, for example, multiple annular elements with multiple supply points along individual rings, in which case the individual rings would each have a different radius. In this context, the elements used for the area distribution may also not be annular, and may for example be similar polygons with different dimensions, for example hexagons with a common center point. Alternatively, the fluid feed may have a spiral design. Additionally, the zone supply may feature a slope, more specifically the fluid supply is sloped such that it is positioned higher on the outside than in the center. Zone supply may alternatively be achieved by a double-cone gas supply system, in which fluid supply from the sides creates a slit-shaped supply through the tapered architecture of the casing. As a result, the fluid is supplied with downward and inwardly directed velocity components, producing a two-dimensional distribution of the fluid. Additionally, the taper may be a narrowed portion leading to a material discharge provided at the bottom end. This embodiment is particularly preferred for a fluid feed provided at the bottom end. Particularly preferably, the double cone gas supply system is supplemented by an additional, parallel fluid feed at the bottom end of the first body. In this case, the fluid feed can take place over the entire area or in a structured manner, for example by means of lateral nozzles. When using two fluid feeds arranged one above the other, preferably the higher one is not implemented with a double cone gas supply system.

In particular the fluid feed need not be horizontal, ie arranged perpendicular to the axis of symmetry. In particular, the fluid feed may be implemented on the outside facing the outer wall, which is higher than the side facing the first body. This is particularly preferred if the fluid feed is firmly coupled to the first body rather than to the outer wall, as this optimizes the force flow.

The first fluid feed and the second fluid feed are arranged one above the other. Preferably, the first fluid feed is provided in the upper 20% of the central zone and the second fluid feed is provided in the lower 20% of the central zone.

The particulate material is in contact with the outer wall and also with the first body. As a result, naturally there is also heat transfer between the particulate material and the outer wall and the first body respectively.

Particulate materials may typically have a particle size of 1 to 5 mm. For example, the average particle size may be 2.5 mm.

In a further embodiment of the invention, the outer wall has a constant first cross-section in the central region. This means in the sense of the invention that the central region has, for example and preferably, a circular cross-section of radius r. The central zone then has this circular cross-section of radius r at every position along the longitudinal axis, resulting in the basic shape of a hollow cylinder. In this case, the outer wall in the central zone can be said to be a tube with constant diameter r. In this embodiment, the first body has a constant second cross-section in the central area, similar to the outer wall.

In a further embodiment of the invention, the diameter of the first body is at least ten times greater than the particle size of the particulate material, the particle size used being the size below which 50% of all particles lie (d _p50 ).

In a further embodiment of the invention, the diameter of the first body is 0.1 to 0.2 times the diameter of the outer wall.

In a further embodiment of the invention, the first body and the outer wall consist of the same material, in particular stainless steel.

In a further alternative embodiment of the invention, the outer wall is composed of a first material (eg stainless steel) and the first body is composed of a second material (eg plastic glass). Particularly preferably, the first material and the second material have comparable roughness.

In a further embodiment of the present invention, the ratio of the diameter of the outer wall to the diameter of the first body in the central region is in the range of 5:1 to 10:1. A particularly preferred ratio is 8:1. In this way, an optimum is achieved between homogenization and reduction of the volume used for particulate material.

In a further embodiment of the invention, the length of the first body, more specifically the length of the straight portion of the first body, exactly corresponds to the length of the central zone.

In a further embodiment of the present invention, the first fluid feed and the second fluid feed have a distance from the outer wall, wherein there is a distance between the first fluid feed and the outer wall and between the second fluid feed and the outer wall. The distances correspond respectively to at least 10 times, preferably 20 times, the particle size of the particulate material, the particle size used being the size below which 50% of all particles are located (d _p50 ). Similarly, the first fluid feed and the second fluid feed have a distance from the first body, wherein there is a distance between the first fluid feed and the first body and between the second fluid feed and the first body. The distances between them respectively correspond to at least 10 times, preferably 20 times, the particle size of the particulate material, the particle size used being the size below which 50% of all particles are located (d _p50 ). Wherein the first fluid feed and the second fluid feed are composed of different elements, for example annular elements, the distance between these elements preferably also corresponds to at least 10 times the particle size of the particulate material, preferably 20 times ground, the particle size used is the size below which 50% of all particles lie (d _p50 ).

In a further embodiment of the present invention, the first fluid feed and the second fluid feed have a distance from the outer wall, wherein there is a distance between the first fluid feed and the outer wall and between the second fluid feed and the outer wall. The distances correspond respectively to up to 120 times the particle size of the particulate material, the particle size used being the size below which 50% of all particles are located (d _p50 ). Similarly, the first fluid feed and the second fluid feed have a distance from the first body, wherein there is a distance between the first fluid feed and the first body and between the second fluid feed and the first body. The distances correspond respectively to up to 120 times the particle size of the particulate material, the particle size used being the size below which 50% of all particles lie (d _p50 ). Wherein the first fluid feed and the second fluid feed are composed of different elements, for example annular elements, the distance between these elements preferably also corresponds to at most 120 times the particle size of the particulate material, and the used The particle size is the size at which 50% of all particles are below this particle size (d _p50 ).

In a further embodiment of the present invention, the first fluid feed and the second fluid feed have a distance from the outer wall, wherein there is a distance between the first fluid feed and the outer wall and between the second fluid feed and the outer wall. The distance between corresponds to 80 times the particle size of the particulate material, and the particle size used is the size at which 50% of all particles are below this particle size (d _p50 ). Similarly, the first fluid feed and the second fluid feed have a distance from the first body, wherein there is a distance between the first fluid feed and the first body and between the second fluid feed and the first body. The distances between them respectively correspond to 80 times the particle size of the particulate material, and the particle size used is the size below which 50% of all particles are located (d _p50 ). Wherein the first fluid feed and the second fluid feed are composed of different elements, for example annular elements, the distance between these elements preferably also corresponds to 80 times the particle diameter of the particulate material, and the particles used The diameter is the size at which 50% of all particles are below this particle diameter (d _p50 ).

In a further embodiment of the invention, the trickle device has a third fluid feed, wherein the third fluid feed is preferably located in the center of the central zone (center point ±10%).

In a further embodiment of the present invention, in the input area, the first body has a tapered shape with the tip pointing upward. In this way an efficient distribution of particulate material is achieved and there is no accumulation of particulate material on the first body.

In a further embodiment of the present invention, in the input area, the tip of the first body has a distance from the material supply line, wherein the distance between the tip and the material supply line corresponds to 50 times to 300 times the particle size of the particulate material. The particle size is the size at which 50% of all particles are below this particle size (d _p50 ). The distance between the tip and the material supply line preferably corresponds to 200 times the particle size of the particulate material.

In a further embodiment of the invention, the first fluid feed and the second fluid feed have a rotationally symmetrical design, in particular an annular or polygonal shape, particularly preferably in the form of a plurality of concentric rings with different diameters.

In a further alternative embodiment, the fluid feed has a spiral design. The spiral fluid feed preferably has an inclination, with the outer side preferably being higher than the inner side. Furthermore, in the case of a spiral fluid feed, the distance between the different zones of the spiral corresponds to 50 to 100 times, more preferably 80 times, the particle size of the particulate material, the particle size used being 50% of all particles to which this Size below particle size (d _p50 ).

In a further embodiment of the invention, the trickle device has a fluid supply line to the first fluid feed and to the second fluid feed, wherein the fluid supply line is provided in the first body. Via this fluid supply line, fluid supplied from the outside reaches the fluid feed and thus the interior of the trickle device.

In a further embodiment of the invention, the first main system in the input zone is supportably joined to the outer wall. Therefore, the first body is actually suspended internally. The advantage is that the flow of particulate material is irregular in the input zone but is no longer disturbed by the support structure in the bottom zone.

In a further embodiment of the invention, the first body is joined to the outer wall in the output zone. As a result, in particular the first body is supported. Particularly preferably, the first body is supportably joined to the outer wall in the input zone and to the outer wall in the output zone. As a result, optimal safety and minimal flow disruption are achieved in the central area.

In a further embodiment of the invention, the fluid supply line section is provided at the connection between the first body and the outer wall in the input area.

In a further embodiment of the present invention, the dripping device is a drying device.

In further embodiments of the present invention, the first body may also have a more complex structure. For example, the first body may be formed from three tubular sub-elements which are joined to each other and formed symmetrically about an axis of symmetry.

Operationally, the volumetric flow of particulate material is preferably established such that the ratio of internal volume to volumetric flow is between 2 and 25, preferably between 3 and 20, more preferably around 18. This means that the average residence time established for the particulate material is from 2 to 25 hours, preferably from 3 to 20 hours, more preferably from 18 hours.

The dripping device of the present invention is explained in more detail below in conjunction with the exemplary embodiments shown in the drawings. Figure 1 First exemplary longitudinal section Figure 2 First exemplary cross-section Figure 3 Second illustrative cross-section Figure 4 Second exemplary longitudinal section

The illustrative embodiments are schematic, not to scale, and serve merely to illustrate the concepts in accordance with the invention.

FIG. 1 shows a first exemplary longitudinal section through the trickle device 10 . The trickle device 10 has an input area 20 located at the top, a central area 30 located below it, and an output area 40 located at the bottom. Material supply line 130 leads to input zone 20 and allows for the supply of particulate material. The particulate material then trickles through the trickling device 10 and can then be removed again via the material drain 140 opened at the output zone 40 . The trickle device 10 has an axis of symmetry 60 . Also situated on this axis of symmetry 60 is a first body 70 which is joined to the outer wall 50 of the trickle device 10 via a support connection 120 in the input area 20 and is thus mechanically fixed. Disposed on the first body 70 are a first fluid feed 80 and a second fluid feed 90 . In the input zone 20 , the first body 70 has a tapered tip 100 , so that the particulate material introduced from the material supply line 130 into the trickle device 10 is reliably guided into the central zone 30 . The tapered tip 100 has an angle of 20° to 120° at the tip, preferably 40°. The output area 40 can also have an angle of 10° to 60°, preferably 45°.

In order to be able to introduce fluid into the interior of the dripping device 10 , the dripping device has a fluid supply line 110 . Through the fluid supply line 110, the fluid passes via the support connection 120 and the first body 70 into the two fluid feeds 80 and 90, where it enters the interior of the trickle device 10 through the fluid outlets, which are advantageously located at both Fluid feeds 80 and 90 at the bottom.

2 and 3 show two different possible exemplary cross-sections along A-A in FIG. 1 .

FIG. 2 shows a circular cross-section of the outer wall 50 and a circular cross-section of the first body 70 . In the example shown, the first fluid feed 80 consists of two annular assemblies and four struts. Both annular components and preferably the struts also have fluid outlets at their bottom ends.

Figure 3 shows a second alternative cross-section. As shown in the first example, the outer wall 50 and the first body 70 have a circular cross-section. Contrary to the first example, the first fluid feed 80 is implemented in a hexagonal form, thereby simplifying the production of the first fluid feed 80 .

The second exemplary longitudinal section shown in FIG. 4 differs from the first exemplary longitudinal section shown in FIG. 1 in that the two fluid feeds 80 and 90 have a slope. This makes it possible to transfer forces more efficiently into the first body 70 through the particulate material arriving from the top.

Reference symbols 10:Trickle device 20:Input area 30:Central area 40:Output area 50:Outer wall 60:Axis of symmetry 70:First subject 80: First fluid feed 90: Second fluid feed 100:Tapered tip 110: Fluid supply line 120:Support connector 130:Material supply pipeline 140: Material discharge

The dripping device of the present invention is explained in more detail below in conjunction with the exemplary embodiments shown in the drawings. Figure 1 First exemplary longitudinal section Figure 2 First exemplary cross-section Figure 3 Second illustrative cross-section Figure 4 Second exemplary longitudinal section

10:Trickle device

20:Input area

30:Central area

40:Output area

50:Outer wall

60:Axis of symmetry

70:First subject

80: First fluid feed

90: Second fluid feed

100:Tapered tip

110: Fluid supply line

120:Support connector

130:Material supply pipeline

140: Material discharge

Claims (19)

A dripping device (10) for particulate materials, wherein the dripping device (10) has an input area (20), a central area (30) and an output area (40), wherein the input area (20) Disposed above the central area (30) and directly adjacent to the central area (30), wherein the central area (30) is arranged above the output area (40) and directly adjacent to the output area (40), wherein The trickle device (10) has an outer wall (50), wherein the central area (30) has a first axis of symmetry (60), and wherein at least a first body (70) is provided in the central area (30), wherein the first body (70) extends over the entire length of the central area (30), wherein the first body (70) has a second axis of symmetry (60), wherein the first axis of symmetry (60) is in contact with the The second axis of symmetry (60) is identical, where the distance between the outer wall (50) and the first body (70) is constant in the central zone, where in the central zone (30) or in the output At least a first fluid feed (80) is provided in the zone (40), wherein the first fluid feed (80) is designed to supply fluid to a zone on the cross-section of the trickle device (10). The trickling device (10) of claim 1, characterized in that the first body (70) in the input area (20) has a tapered shape with a tip pointing upward. The trickle device (10) of claim 1 or 2, characterized in that a second fluid feed (90) is provided in the central zone (30), wherein the second fluid feed (90) is designed to Fluid is supplied to the area on the cross-section of the trickle device (10). The trickle device (10) of any one of claims 1 to 3, characterized in that the first fluid feed (80) and the second fluid feed (90) have an annular, spiral or hexagonal shape. design. The trickle device (10) of any one of claims 1 to 4, characterized in that the trickle device (10) has a first fluid feed (80) and a second fluid feed (90). A fluid supply line (110), wherein the fluid supply line (110) is disposed in the first body (70). A trickle device (10) according to any one of claims 1 to 5, characterized in that the first body (70) in the input area (20) is supportingly engaged with the outer wall (50). The trickle device (10) of claims 5 and 6, characterized in that the fluid supply line (110) is partially provided at the connection between the first body (70) and the outer wall (50) in the input area (20) In the center. The dripping device (10) according to any one of claims 1 to 7, characterized in that the dripping device (10) is a drying device. The trickle device (10) according to any one of claims 1 to 8, characterized in that the first body and the outer wall are made of the same material. The trickle device (10) of any one of claims 1 to 8, characterized in that the outer wall is composed of a first material, and the first body is composed of a second material. The dripping device (10) of item 10, characterized in that the first material and the second material have considerable roughness. The trickle device (10) of any one of claims 1 to 11, characterized in that the ratio of the diameter of the outer wall in the central area to the diameter of the first body is in the range of 5:1 to 10:1. The trickle device (10) of any one of claims 1 to 12, characterized in that the first fluid feed and the second fluid feed are at a distance from the outer wall, wherein the first fluid feed and the outer wall are at a distance. The distances between the outer walls and between the second fluid feed and the outer walls respectively correspond to at least 10 times the diameter of the particulate material particles. The trickle device (10) of any one of claims 1 to 13, characterized in that the first fluid feed and the second fluid feed are at a distance from the first body, wherein the first fluid feed The distances between the first body and the second fluid feed and the first body respectively correspond to at least 10 times the particle size of the particulate material. The trickle device (10) of any one of claims 1 to 14, characterized in that the first fluid feed and the second fluid feed are at a distance from the outer wall, wherein the first fluid feed and the The distances between the outer walls and between the second fluid feed and the outer walls respectively correspond to at most 120 times the particle size of the particulate material. The trickle device (10) of any one of claims 1 to 15, characterized in that the first fluid feed and the second fluid feed are at a distance from the first body, wherein the first fluid feed The distances between the first body and the second fluid feed and the first body respectively correspond to at most 120 times the particle size of the particulate material. The trickle device (10) of any one of claims 1 to 16, characterized in that the first fluid feed and the second fluid feed are at a distance from the outer wall, wherein the first fluid feed and the The distances between the outer walls and between the second fluid feed and the outer walls respectively correspond to 80 times the particle diameter of the particulate material. The trickle device (10) of any one of claims 1 to 17, wherein the first fluid feed and the second fluid feed are at a distance from the first body, wherein the first fluid feed The distances between the first body and the second fluid feed and the first body respectively correspond to 80 times the particle diameter of the particulate material. The dripping device (10) according to any one of claims 1 to 18, characterized in that, in the input area, the tip of the first body is at a distance from the material supply line, wherein the tip is at a distance from the material supply line. The distance between them corresponds to 50 to 300 times the particle size of the particulate material.