EP1637824B1 - Granular material cooler - Google Patents

Abstract

The machine for tempering of bulk materials has a through flow passage (2) for the material under gravity. The though flow passage extends between input (1) and discharge (3) headers and has a heat exchange function. There is a bypass pipe (27) for the heat exchange section, which extends between the input header and the outlet side of the discharge header funnel.

Description

In such, hereinafter referred to as bulk material heat exchanger devices occur in the level control problems. These problems, which are due to numerous causes, mean that different bulk material temperatures can occur at the outlet of the bulk material heat exchanger. Furthermore, an interruption is necessary when carrying out cleaning work. Finally, in case of blockages or partial blockages of the bulk material heat exchanger considerable disturbances may occur.

From the EP 0 973 716 B 1 is a bulk material heat exchanger is known which is designed for cooling of crystalline carboxylic acids. The bulk material is fed to the heat exchanger in the lower region and fluidized there. The coarser particles flow down from below. The finer particles are transported in a fluidized bed through a cooling zone and discharged from the heat exchanger above the cooling zone. The conveying air is drawn upwards and can be used for downstream transport to a silo.

The invention is therefore based on the object, a device of the general type in such a way that a trouble-free operation is possible.

This object is achieved by the features of claim 1.

The essence of the invention is that when exceeding a predetermined by the location of the inlet opening of the overflow pipe in the buffer section bulk material level in the buffer section, the bulk material flows through the overflow pipe and only after the bulk material heat exchanger again is merged with the bulk material flow, which adjusts a mixing temperature in the bulk material. In case of a temporary decommissioning by a malfunction, z. As a blockage, the bulk material heat exchanger, the entire flow of bulk material can flow through the overflow pipe. As a rule, the discharge sluice is operated in such a way that a considerable proportion, as a rule at least 80 percent of the normally occurring quantity of bulk material, is passed through the bulk material heat exchanger. In addition, going quantities are then passed through the overflow pipe as it were in the bypass on the bulk material heat exchanger. The overflow pipe has a large nominal diameter, which is usually larger than that of a upstream pneumatic conveying line, is supplied via the bulk material. With a large nominal size, the bulk material can flow through the overflow pipe without causing excessive pressure loss.

In the further embodiment according to claim 2 and the entering into the buffer section conveying air is discharged through the overflow pipe. This embodiment offers u. a. in a further development according to claim 3, in which case the total venting takes place only in a downstream silo.

According to a further embodiment according to claim 4, the bulk material heat exchanger is integrated with the overflow pipe in a pneumatic conveying line, wherein the supplied with an incoming feed line bulk material at least predominantly in the bulk material heat exchanger is tempered and wherein the conveying air is passed through the overflow pipe at the bulk material heat exchanger and is merged behind this again with the bulk material flow. As a result, a further promotion then takes place in a continuing delivery line. Especially in this embodiment, it is advantageous that the overflow pipe has a large nominal diameter. In a the bulk material heat exchanger downstream as discharge organ rotary valve then there is no differential pressure at this. Such a differential pressure would namely lead to leakage air, which would flow counter to the bulk material in the bulk material heat exchanger and would lead to disturbances of the bulk material flow. Such a negative effect would occur especially in fine-grained or powdery bulk materials.

Alternatively, the tempered in the bulk material heat exchanger bulk material can also be introduced into a downstream delivery line, including the development according to claim 5 indicates a solution.

Through the developments according to claims 6, 7 and 8 it is achieved that the venting of the bulk material heat exchanger downstream devices via the overflow pipe. This is especially true for the leakage air exiting the feed gate.

Claim 9 finally shows that a closed conveying gas circuit can also be provided, which may be expedient in particular when nitrogen is used as conveying gas instead of conveying air.

In principle, the bulk material heat exchanger can be designed in the usual way. Thus, the product can by parallel arranged plates or transversely to the flow direction of the bulk material pipes of various different Cross-sectional shape in which the heat transfer fluid flows flows; but is particularly advantageous embodiment according to claim 10.

Claim 11 specifies a concretization of the cross-sectional conditions of the pneumatic delivery line and the overflow pipeline, wherein it is ensured by these cross-sectional relationships that a regulation of the bulk material level in the buffer section is not required.

Fig. 1

eine Vorrichtung nach der Erfindung in vertikalem Längsschnitt in schematischer Darstellung,

Fig. 2

eine Anordnung einer Vorrichtung nach der Erfindung auf einem Silo,

Fig. 3

eine Anordnung einer Vorrichtung nach der Erfindung in einer pneumatischen Förderung,

Fig. 4

eine Vorrichtung nach der Erfindung mit vorgeordne-ter Schwerkraft-Zuführung von Schüttgut und nachgeordneter pneumatischer Förderung,

Fig. 5

eine Fig. 4 entsprechende Anordnung jedoch mit pneumatischer Zuführung des Schüttguts zur Vorrichtung und

Fig. 6

eine Anordnung einer Vorrichtung nach der Erfindung mit einer Kreislaufführung des Fördergases.

Further features, advantages and details of the invention will become apparent from the following description of exemplary embodiments with reference to the drawing. It shows

Fig. 1

a device according to the invention in vertical longitudinal section in a schematic representation,

Fig. 2

an arrangement of a device according to the invention on a silo,

Fig. 3

an arrangement of a device according to the invention in a pneumatic conveying,

Fig. 4

a device according to the invention with pre-ordered gravitational feed of bulk material and downstream pneumatic conveying,

Fig. 5

a Fig. 4 corresponding arrangement, however, with pneumatic feed of the bulk material to the device and

Fig. 6

an arrangement of a device according to the invention with a circulation of the conveying gas.

In the FIG. 1 illustrated device for controlling the temperature of bulk material has an upper buffer section 1, a central heat exchange section 2 and a lower discharge section 3. The sections 1, 2, 3 each have circular cross sections. The housing-like, substantially enclosed buffer section 1 is provided with an upper inlet nozzle 4 for supplying a bulk material to be tempered. The inlet nozzle 4 is preferably introduced tangentially into the buffer section 1 in order to effect a good separation of the bulk material along the inner wall of the buffer section 1. This device is also referred to below as a bulk material heat exchanger.

The heat exchange section 2 has a housing 5, in whose interior space 6 heat exchanger tubes 7 are arranged parallel to each other at a distance from each other. The interior 6 is therefore a heat exchange space.

Adjacent to the discharge section 3 opens into the interior 6 of the housing 5 of the heat exchange section 2, a supply nozzle 8 for heat transfer fluid. Adjacent to the buffer section 1 opens a discharge nozzle 9 from the interior 6 of the housing 5. In the interior 6 deflecting plates 10 are each transversely to the longitudinal direction of the tubes 7 at a distance from each other mounted such that a supplied via the supply nozzle 8 heat transfer fluid according to the flow directional arrow 11 meandering through the interior 6 each transverse to the longitudinal direction of the tubes gradually upward to the discharge nozzle 9 flows. The heat exchange section 2 is therefore for a cross-countercurrent designed the heat transfer fluid. The interior 6 can be filled with a tube 7 enveloping bed 12 of glass beads, steel balls and plastic granules, which contributes to the improvement of the heat transfer between the heat transfer fluid and the tubes 7. The filling of this bed in the interior 6 via the discharge nozzle 9; a possible removal takes place via the supply nozzle 8. To secure the bed in the interior 6 removable retaining sieves 13 are arranged in the socket 8, 9. The size of the particles of the bed 12 should be such that they can be introduced into them after the heat exchange section 2 has been manufactured. The particles of the bed 12 must therefore in any case be smaller than the pitch of the tubes 7. The particles of the bed 12 are preferably spherical, lens or cylindrical shape.

The tubes 7 are connected at the top in an inlet tube plate 14 fixedly connected to the housing 5 and at the bottom with an outlet tube plate 15 in such a way that they are open towards the buffer section 1 and the discharge section 3. Between the buffer section 1 and the heat exchange section 2 on the one hand and the heat exchange section 2 and the discharge section 3 are flange connections 16 and 17. As the drawing is removed, the inlet tube plate 14 is configured in that each tube 7 has an inlet funnel 18 which widens toward the buffer section 1 and thus narrows towards the respective tube 7, with adjacent funnels 18 in turn being dimensioned so that they meet at the top in a relatively sharp edge 19. The inlet funnels 18 have an opening angle α which is at least 30 ° and at most 120 °, but is preferably in the range from 40 ° to 100 °. This avoids that in the inlet tube plate 14 between adjacent tubes 7 dead spaces or dead surfaces arise on which bulk material 20 remains, which is not supplied to a pipe 7 by gravity, especially when emptying the heat exchange section 2 and therefore remains on the inlet tube sheet 14.

On the outside of the housing 5 vibrators 21 are mounted, by means of which the entire heat exchange section 2 and thus the tubes 7 are vibrated, whereby a heat transfer on the inside of the tubes 7, ie between them and the bulk material 20 is improved ,

The discharge section 3 is in the form of a downwardly tapered cone-shaped funnel. Such a shape causes the bulk material 20 flows in the discharge section 3 at all points of an arbitrarily selected cross section with almost the same speed, in this consideration, the immediate wall area is not taken into account, since there is always a delay due to wall friction. As a discharge device a cellular wheel lock 22 is provided, the housing 23 is connected via a downpipe 24 with the discharge section 3. In the housing 23, a cellular wheel 25 is arranged, which is rotatably driven by a motor 26. Except cellular wheel locks are of course other discharge facilities into consideration, such. B. discharge screws, vibrating troughs or metering slides.

From the buffer section 1 opens an overflow pipe 27. This overflow pipe 27 leads past the heat exchange section 2 and at the discharge section 3 and opens below the feeder lock 22 serving as a sluice in a discharge pipe 28. The inlet opening 29 of the overflow pipe 27th is about halfway up the buffer section 1. Like Fig. 1 can be removed, the bulk material level 30 in the buffer section 1 is approximately such that at a the inlet opening 29 of the overflow pipe 27 reaching or exceeding bulk material level 30, the excess bulk material 20 through the overflow pipe 27th flows. Due to the tangential feeding of the bulk material through the inlet nozzle 4 in the buffer section 1, a uniform, ie approximately level equal filling of the buffer section 1 is achieved. This ensures that not too much bulk material is entrained with the conveying air in the overflow pipe 27. As soon as the bulk material level 30 drops to or below the level of the inlet opening 29, the outflow of bulk material 20 through the overflow pipeline 27 may be zero. As a result, fluctuations in the bulk material supply via the inlet nozzle 4 can be compensated. Furthermore, disturbances in the bulk material transport through the heat exchange section 2 and in the area of the cellular wheel lock 22 can be compensated.

Fig. 2 shows a bulk material heat exchanger on a silo 31. The buffer section 4 is fed via a pneumatic conveying line 32 in the conveying direction 33 bulk material 20, which enters through the inlet nozzle 4 in the buffer section 1. The promotion of most of the bulk material 20 takes place through the heat exchange section 2 and the discharge lock 22 and the discharge pipe 28 in an inlet 34 of the silo 31. The through the feed line 32 with the bulk material 20 in the buffer Section 1 funded conveying air is completely conveyed through the overflow pipe 27 into the silo 31 and exits there through an exhaust port 35. In the latter, a filter 36 is regularly arranged. This configuration and arrangement is particularly suitable when using very large silos 31 with large diameter, namely where the inlet 34 and the exhaust air nozzle 35 have the greatest possible distance, for example, 10 m from each other, so that a sufficient calming of the entering into the silo 31 conveying air takes place.

In the arrangement according to Fig. 3 is a bulk material heat exchanger integrated into a pneumatic conveying line 37 and thus stands during operation under positive or negative pressure, since in the pneumatic conveying line 37 basically a suction or a pressure promotion can take place. The delivery line 37 occurs - as already in Fig. 2 described - via the inlet nozzle 4 in the buffer section 1 a. The discharge pipe 28, in which the overflow pipe 27 opens, in turn passes into the further conveying line 38. The overflow pipe 27 is thus part of the air conveyor system, wherein only in the region of the heat exchange section 2, the conveying air and the bulk material 20 are at least largely separated from each other. Behind the discharge lock 22 of the bulk material flow and the conveying air are brought together again. In the incoming delivery line 37 and the continuing delivery line 38, a switch 39, 40 are provided in each case, which are connected to one another via a bypass line 41. In the case of severe faults in the device for controlling the temperature of bulk material 20 or during cleaning of this device, the bulk material 20 can then be conveyed past the device. Especially in this embodiment, it may be appropriate if a radiator 27 a is integrated into the overflow pipe 27, so that the conveying air is cooled. Such a cooler 27a may be, for example, a double-pipe or shell-and-tube heat exchanger.

In the arrangement according to Fig. 4 the bulk material 20 is fed to the buffer section 1 by gravity. For example, it is in the bulk material 20 to plastic granules, which is supplied from an extruder 42 with subordinate underwater granulation 43 a dryer 44. From there, it passes through a classifying sieve 45 by gravity via the inlet nozzle 4 into the buffer section 1. The discharge gate 22 is hereby followed by a so-called closed pre-container 46, into which the discharge pipe 28 discharges. The overflow pipeline 27 also opens into this pre-container 46, from which a motor-driven cellular wheel lock 47 serving as a feed lock enters the bulk material 20 into a pneumatic delivery line 48. The conveying air is generated by means of a blower 49. The promotion takes place in the conveying direction 33. The leaking from the cellular wheel lock 47 in the pre-tank 46 leakage air is discharged via the overflow pipe 27 into the buffer section 1, from which it exits through an exhaust port 50. The delivery through the delivery line 48 takes place to silos 51, 52.

The design after Fig. 5 is different from the after Fig. 4 only in that the supply of the bulk material 20 already takes place via a pneumatic conveying line 32, as in the arrangement according to Fig. 2 the case is. In addition to the leakage air from the pre-tank 46, the entire conveying air is blown off from the pneumatic conveying line 32 via the exhaust air nozzle 50.

The arrangement after Fig. 6 is different from the after Fig. 5 in that a cycle of the delivery gases is provided; This is for example of interest if, instead of conveying air nitrogen is used as a conveying gas. By the first feed line 32 bulk material 20 is input via the inlet nozzle 4 in the buffer section 1. The exhaust pipe 50 is connected via a connecting line 53 with a radiator 54 and a safety filter 55 to the blower 49. Here too will the leakage air from the cellular wheel lock 47 and the upstream pre-tank 46 via the overflow pipe 27 into the buffer section 1 and fed from there via the exhaust port 35 and the connecting line 53 of the second delivery line 48.

By cooling the conveying gas in the cooler 54, the bulk material in the conveying line 48 is additionally cooled. A lower mixing temperature of bulk material and conveying gas, which corresponds to the starting temperature of the cooled conveying gas, is already established after a few meters of conveying. This is an advantage of the arrangement Fig. 6 opposite to the Fig. 3 ,

Claims (11)

1. Device for tempering bulk material (20) comprising °

   - a heat exchanger section (2) through which bulk material (20) may flow in a direction of gravity,

   - a buffer section (1) for the bulk material (20), which buffer section (1) comprises a bulk material inlet (4) and is arranged upstream of the heat exchanger section (2) in the direction of gravity,

   - a discharge section (3) for discharging a bulk material flow, the discharge section (3) being arranged downstream of the heat exchanger section (2) in the direction of gravity,

   - a discharge device (22), which is associated with the discharge section (3), for the bulk material which is discharged from the discharge section (3), and characterized in that an overflow pipe (27) is provided for bulk material (20),

   -- with an inlet opening (29) of said overflow pipe (27) leading out of the buffer section (1), and

   -- with the overflow pipe (27) guiding into the discharged bulk material (20).
2. Device according to claim 1, characterized in that a pneumatic conveyance line (32, 37) for bulk material (20) projects into the bulk material inlet (4).
3. Device according to claim 1 or 2, characterized in that a silo (31) is arranged downstream of the discharge device (22), that the overflow pipe (27) guides into the discharged bulk material (20) downstream of the discharge device (22), and that all air is extracted from the silo (31).
4. Device according to claim 2, characterized in that the overflow pipe (27) and the discharge device (22) merge to form a continuous conveyance line (38).
5. Device according to claim 1, characterized in that an inlet feeder (47) for a pneumatic conveyance line (48) is arranged downstream of the discharge device (22), and that the overflow pipe (27) guides into the discharged bulk material (20) between the discharge device (22) and the inlet feeder (47).
6. Device according to claim 5, characterized in that a reservoir (46) is arranged upstream of the inlet feeder (47), and that the discharge device (22) and the overflow pipe (27) guide into the reservoir (46).
7. Device according to claim 5, characterized in that the reservoir (46) is closed.
8. Device according to claim 5, characterized in that the buffer section (2) is provided with an air exhaust (50).
9. Device according to claim 8, characterized in that the air exhaust (50) is connected with the pneumatic conveyance line (48) via a connection line (53) comprising a blower (49).
10. Device according to claim 1, characterized in that in the heat exchanger section (2) are arranged heat exchanger pipes (7) which are arranged in the direction of gravity and are connected with the buffer section (2) and the discharge section (3).
11. Device according to claim 2, characterized in that the overflow pipe (27) has a cross-section which is at least equal to but preferably at least twice the cross-section of the pneumatic conveyance line (32, 37).

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