WO2012084406A2

WO2012084406A2 - Device for cooling a pourable or liquid product

Info

Publication number: WO2012084406A2
Application number: PCT/EP2011/070968
Authority: WO
Inventors: Klaus Lemke
Original assignee: Tridelta Hartferrite Gmbh
Priority date: 2010-12-22
Filing date: 2011-11-24
Publication date: 2012-06-28
Also published as: CA2822482C; JP2014512499A; DE102010055706A1; US20140083118A1; WO2012084406A3; EP2655997A2; CA2822482A1; CN103380348A

Abstract

The invention relates to a device for cooling a pourable or liquid product, comprising a container (1) for receiving or conveying the pourable or liquid product. A plurality of cooling zones (13a, 13b, 13c) are provided along the container (1) in the direction of conveyance of the pourable or liquid product. According to the invention, said cooling zones (13a, 13b, 13c) are embodied in such a manner that they can be supplied with a respective cooling medium (15a, 15b, 15c) independently from each other. Said device also comprises control means in order to control the cooling power of the individual cooling zones (13a, 13b, 13c) independently from each other.

Description

Device for cooling a free-flowing or flowable product

The invention relates to a device for cooling a free-flowing or flowable product, such as strontium hexaferrite in the form of granules or the like in the production of hard ferrites.

In many technical processes, often the

Task to transport a free-flowing or flowable product after passing through a furnace and thereby cool. It is customary to use water-cooled rotary tubes or screws.

The free-flowing or flowable product, which leaves the oven at a temperature of, for example, more than 1000 ° C., is cooled during transport by means of this water-cooled rotary tube. An example of such a rotary tube or tube screw cooling is disclosed in the German utility model DE 20106822 ül.

However, it is desirable to dissipate the heat given off to the cooling medium during cooling to some extent

recover. In this context, the

Patent Application DD 281451 A5 before to provide along a rotary drum a plurality of rotating heat exchangers, which have a common supply line, and their derivatives via changeover valves either with a common

Circulation line or are connected to a stationary heat exchanger. The switching of the switching valves via a control unit according to temperature measurements of

Cooling medium, so that it is possible, that on the rotary drum accumulating waste heat a consumer with the highest possible and constant temperature and continuously

provide. In that regard, this document shows the subject of the preamble of claim 1.

A disadvantage of the shown in this document

Technology is that, since all the forward and return flows of the individual cooling areas connected to a line and connected to valves, only a kind of cooling medium can be applied. This construction also entails that a constant flow velocity is predetermined. The control is done only by

Changeover valves.

In addition, reference is made to the document DE 3320595 AI, in which a screw conveyor for discharging solid residues from under high temperature and pressure operated devices is shown, consisting of two

Constructed sections that have separate cooling devices. This document deals with the problem that in the screw conveyor further crushing of the product takes place, which in turn leads to a greater wear of a portion of the screw. In order to exchange this part effectively, it is intended to build the screw conveyor in two sections.

The object of the invention is to provide an improved device for cooling a free-flowing or flowable product, which enables a more efficient recovery of the heat as well as more degrees of freedom in carrying out the cooling process.

The problem is solved by a device according to

Claim 1. The dependent claims relate to further advantageous aspects of the invention. In the following, a preferred embodiment of the invention with reference to the accompanying figures will be described in detail.

In the figures show:

Figure 1 is a cross-sectional view through the

Cooling device according to the invention;

FIG. 2 is a cross-sectional view taken along the line A-A in FIG

FIG. 1;

Figure 3 shows an enlarged detail of Figure 1 with

Details of the guidance of the cooling medium;

Figure 4 shows a further detail enlargement of Figure 1 to illustrate the leadership of the supply and

Discharge of the cooling medium; and

Figure 5 is a Schetnatic diagram of the invention

Cooling device with the associated control and

Heat exchangers.

In the following, an apparatus according to the invention for cooling a free-flowing or flowable product will be described with reference to the example of the production of hard ferrite material, in particular a strontium ferrite (SrFei ₂ 0 ₁₉ ). An example of such a hard ferrite is described in the application EP 08172099. The production of a ferrite is just one example of one

Possible application of the device according to the invention for cooling a free-flowing or flowable product.

Other examples can be found in the food industry, in the cooling of crude carbide melts, soft ferrites, general ceramics, building materials, cement, lime and much more. For example, the invention can be used advantageously wherever the starting product of a rotary kiln has to be cooled. As is known, to produce a strontium ferrite, iron oxide, strontium carbonate and additives are first mixed in small amounts. The mix is present as Granalie or slurry and is in one

Rotary kiln given.

At temperatures between 1400 and 1500 ° C strontium hexaferrite forms in the form of glowing granules with a diameter between 4 and 25 mm, which the

Leave rotary kiln and then as efficiently and quickly to a temperature of 240 ° C, preferably 75 ° C and more preferably 50 ° C or less should be cooled.

According to the invention, therefore, the starting material of

Rotary kiln introduced into a container 1,

for example via a product chute 6. In the container 1, the product is transported or conveyed. This can advantageously by a on the inner wall of the

Turned tubes welded spiral 3 done.

In other words, this embodiment is based on a rotary tube. But it is also contemplated to use other containers, for example, those in which the transport takes place only by gravity such as in a

Well cooler, optionally with the support of appropriate vibrating screens.

According to the invention along the conveying direction a

A plurality of cooling zones 13 a, 13 b, 13 c formed around the container 1.

These cooling zones 13a, 13b, 13c are designed so that they can be supplied independently with a respective cooling medium 15a, 15b, 15c. For this purpose, according to the invention, the container 1 as a double-jacket tube, for example made of sheet steel in welded or rolled design. The first cooling zone 13a is configured in the example according to the invention to allow cooling with thermal oil as the cooling medium. The second and third zones 13b, 13c are designed for operation with water as the cooling medium.

The container 1 is provided at one end with a drive pin, while at the other end an end pin is attached. The two pins are held in journal bearings 8.

To supply the cooling medium bushings 7 in the area of the drive and end pin 5 are executed. In the preferred embodiment, these are rotary joints at which, not shown in the figures, flexible

Connecting lines can be provided.

The drive of the container 1 for rotation with a

Rotation speed of a few revolutions per minute in the embodiment, for example, via a high-performance chain drive (not shown) with a corresponding control, so that the

Rotation speed can be adapted to the needs.

In the container 1 shown, for example, the following conditions can be set advantageously for the production of the strontium ferrite.

For a capacity of about 600 kg / h of

Strontium ferrite with a solids density of about 5 t / m »and a specific heat capacity of 0.8 to 1.0 kJ / (kg-K) has a container 1 of about 5 m Length at a diameter of about 60 cm proved sufficient and effective.

According to the invention, the device for cooling the

free-flowing or flowable product with a

Control means equipped, which makes it possible, the

Cooling capacity of the individual cooling zones 13a, 13b, 13c to control. It is also particularly advantageous to design the control means as a control, whereby via corresponding sensors for temperature,

Flow speed, pressure, rotational speed of the rotary drum, speed of free-flowing or

flowable product or throughput of the product and via corresponding actuators together with a control circuit automatic operation is possible.

For example, at a temperature of

Product infeed of about 1000 ° C and a temperature of the product outlet of 75 ° C following target values are given.

For the first cooling zone 13a in which thermal oil is used as the cooling medium 15a, a temperature of the supplied cooling medium of 110 ° C is selected, and the temperature of the discharged cooling medium is controlled to 135 ° C. The amount of thermal oil used for this purpose is about 5 m * / h at a maximum pressure of 7 bar. The flow of the cooling medium preferably takes place counter to the conveying direction of the product.

In a second cooling zone 13b results in a

Product inlet temperature of 600 ° C, and a temperature at the outlet of the product of 250 ° C. Water is used as the cooling medium, which is supplied at a temperature of 45 ° C, and discharged at a temperature of 95 ° C again becomes. The amount of water is 4 m ³ / h at a pressure of 3 bar.

In the third cooling zone 13c then the temperature of the product inlet is 250 ° C, and the product outlet results in a temperature of 75 ° C. For this purpose, water is used as

Cooling medium supplied with a temperature of 10 ° C, and the discharge temperature of the water is about 12 ° C. The amount of water in the third cooling zone 13c may be adjusted to, for example, 14 m * / h. Again, the pressure at 3 bar is specified.

According to the invention for each cooling zone 13a, 13b, 13c, the inlet temperatures of the supplied cooling medium, the

Return temperature of the discharged cooling medium, the

Product outlet temperature of the cooling zone leaving free-flowing or flowable product, the pressure of the cooling medium or its flow rate per hour are controlled in a wide range. While the respective inlet temperatures, the flow velocity of the

Cooling medium and its pressure as primary variables by suitable means, such as heat exchangers, pumps and

Valves, can be adjusted, the control of other parameters, such as the return temperature of the discharged cooling medium, and the product outlet temperature of the cooling zone leaving free-flowing or

flowable product rather indirectly, for example by adjusting the rotational speed of the rotary tube and thus the speed of the free-flowing or flowable product, and the flow rate of the flowable or flowable product.

With regard to the design of the spiral 3, such as

Slope, ridge height and the like, there are no special limitations, the goal is a reliable transport at at the same time good heat dissipation to the wall of the

Ensure rotary tube.

As sensors, temperature sensors are preferably provided in the device according to the invention, which measure the supply temperature of the cooling medium for each zone, as well as the return temperature of the from each cooling zone

discharged cooling medium. Further temperature sensors, which are accommodated, for example, in a hub having a plurality of spokes, which may be provided at a transition from one cooling zone to the next, and which transmit the measured value wirelessly or by a line in a shaft in the rotary tube, measure the temperature of the respective cooling zone

product, or the temperature of the product on the product chute 6 and the temperature of the product at the outlet of the cooling device. Furthermore, in the device according to the invention pressure sensors and

Flow sensors may be provided to determine the pressure and the flow rate of the cooling media.

About appropriate actuators, heat exchangers, pumps, valves is then a corresponding control or regulation

possible.

In the apparatus for cooling the free-flowing or flowable product according to the invention, the

Supplying the cooling medium of the first cooling zone 13a preferably through a passage 7, namely a rotary feedthrough, in the region of the one pin 5. To prevent the hot thermal oil of the first cooling zone 13a unnecessarily removing the cooling medium of the second or third zone 13b, 13c, the cooling medium of the first zone 13a is discharged again on the same side on which the feed was also carried out. In contrast, the cooling medium for the second and third cooling zone 13b, 13c, namely water, on the other side of the container 1 via the other pin 5 through corresponding rotary feedthroughs 7 is supplied. The flow of the cooling medium preferably takes place counter to that

Conveying direction of the product.

The cooling medium of the second and third cooling zones can either be discharged on the same side to which it was supplied, or it is possible, for example, to discharge the cooling medium of the central cooling zone 13b also on the side where the cooling medium is supplied to the first cooling zone 13a ,

According to the invention it is provided to use the thermal oil, which was used as the cooling medium of the first cooling zone 13a, to provide hot water for residential and working buildings via a heat exchanger. Alternatively, the heat of the thermal oil can also be used to the

The starting materials of ferrite production, namely the iron oxide, strontium carbonate and the additives, preheat before entering the furnace so as to reduce the total energy consumption of the furnace.

The cooling medium of the second cooling zone 13 b can be used to heat energy for neighboring living or

Provide work building, or can be in one

District heating network can be fed.

Figure 2 shows a cross section through the device for cooling of Figure 1 along the line AA. As shown in FIG. 2, the container 1 has an inner tube 2, so that a double-walled casing is formed, in which the cooling medium 15 is guided. Inside the container 1, the spiral 3 or screw is provided for the Promote the product. Spokes 4 are welded to the wall of the rotary tube and connect the rotary tube to a pin or shaft 5. The pin 5, which is guided on both sides of the container in corresponding pins and bearings 8, rotates the entire container 1 about its longitudinal axis.

FIG. 3 shows a section of FIG. 1 in a preferred embodiment of the container 1 according to the invention. For better cooling, it is provided that the double-walled jacket of the container 1 is provided with guide plates 12 which guide the cooling medium 16 in a suitable manner. Between the individual cooling zones 13a, 13b, 13c, the double-walled area is separated by corresponding separating bulkheads 10. To simplify the construction, it is possible to provide supply and discharge lines 11 for the cooling medium on the outside of the container 1.

Finally, FIG. 4 shows a broad section from FIG. 1, the region of the product chute 6 and the peg 5 and the passages 7 for the supply and removal of a cooling medium being shown in greater detail.

Preferably, the cooling medium is supplied via a rotary guide in the region of the pin and also discharged again.

As previously described, the device is for

Cooling of the example shown in the figures to a

Amount of 600 kg / h designed in the production of strontium ferrite. Calculations have shown that the

Cooling device with appropriately adapted control can also handle a throughput of up to 1000 kg / h of the same material. The cooling then reaches the same

Coolant use, however, only for cooling the

Strontium ferrits to values above 75 ° C on the output side. Therefore it is in a preferred embodiment possible to provide a fourth cooling zone, ie to hang another double-walled tubular element to the rotary tube.

In the embodiment shown in FIG. 1, all the cooling zones are designed to be of equal length. This is by no means mandatory. Depending on the application, it is possible and useful to make individual cooling zones shorter or longer.

If the cooling medium can be supplied to the first zone 13a with a very low temperature, it is possible for the thermal stress to cause the granules to "burst", so that in a subsequent grinding step

Energy can be saved.

Figure 5 shows schematically the structure of the cooling device 1 for the flowable or flowable product together with the heat exchangers and the associated control device.

In the embodiment shown in Figure 5 is the

Device for cooling divided into three sections. The first section 13a is cooled with thermal oil as described above. About a pump 19 a and a

Flow meter 21a is the thermal oil through the

Double-walled wall of the cooler 1 for the

free-flowing or flowable product. The thermal oil flowing out of the cooling device 1 passes through a thermal sensor 23a to a switching valve 29. This switching valve 29 is designed such that it can direct some or all of the thermal oil to an emergency heat exchanger 17.

In a similar manner, the cooling medium of the central portion 13 b of the cooling device via the pump 19 b, the Flow meter 21 b led into the Kühlvorrichtving, and supplied via the thermal sensor 23 b and the switching valve 31 wholly or partially the emergency heat exchanger 17.

Another switching valve 33 is at the inflow of the

Emergency heat exchanger 17 provided.

The emergency heat exchanger 17 in turn is in communication with a cooling circuit with the switching valve 33, so that a continuous flow of water to a cooling pool 35 and back is possible. This cooling pool 35 is also the

Reservation from which the cooling medium of the third section 13c of the cooling device via a pump 19c, a

Flow meter 21c and a thermal sensor 23c is fed. In this way, the heat can safely from the

Cooler be transported away.

Further thermosensors 25, 27 and 28 are provided to control the temperature at the outlet of the respective flows of the

Emergency heat exchanger 17 to measure.

The system described above is the emergency or

Reserve System. The valves 29 and 31 forward the respective cooling media only to the emergency heat exchanger 17 when the actual consumers, which are not shown in Figure 5, have no way to absorb the heat.

Preferably, as described above, the

Thermal oil or the cooling water of the central portion 13 b to connect with respective heat storage, so that the waste heat can be used to provide, for example, service water or heating power. Alternatively, it is possible that the product supplied to the rotary kiln with the Waste heat is preheated.

In the example shown, two different

Cooling media, namely thermal oil and water used. Again, the invention is not limited. For example, it is also possible to operate a further cooling zone with air cooling, or to use another cooling medium, for example glycerol.

Particularly advantageous, the inventive

Device for cooling a free-flowing or

flowable product in connection with the production of a strontium ferrite proved in a rotary kiln. However, the invention is not limited thereto and can be advantageously used in many places when it comes to cool a free-flowing or flowable product from a relatively high temperature quickly and effectively, while the waste heat for a

To provide further use in a suitable manner.

Claims

claims

1. Apparatus for cooling a free-flowing or

flowable product, with:

a container (1) for receiving and conveying the free-flowing or flowable product;

a plurality of cooling zones (13a, 13b, 13c) which are formed along the container (1) in the conveying direction of the free-flowing or flowable product,

characterized in that

at least two cooling zones (13a, 13b, 13c) are configured to independently with each other

Cooling medium (15a, 15b, 15c) to be supplied;

the apparatus further comprising control means for controlling a cooling capacity of the individual cooling zones (13a, 13b, 13c).

2. Device according to claim 1, characterized in that the container (1) is a rotary drum with an inner spiral (3).

3. A device according to claim 2, characterized in that the rotary drum (1) is double-walled, and the cooling zones (13a, 13b, 13c) are respective separate wall sections, for guiding the respective cooling medium (15a, 15b, 15c) in the separate wall sections are formed.

4. Apparatus according to claim 2 or 3, characterized

characterized in that the control means is arranged to control at least one of the following parameters for at least one cooling zone:

Temperature of the supplied cooling medium,

Temperature of the discharged cooling medium, T perature of the cooling zone (13a, 13b _" 13c) leaving free-flowing or flowable product,

Flow velocity of the cooling medium (13a, 13b,

13c)

Pressure of the cooling medium (13a, 13b, 13c),

Rotational speed of the rotary drum,

Speed of free-flowing or flowable product and / or

Throughput of free-flowing or flowable product.

5. Device according to one of the preceding claims, characterized in that the cooling medium is at least one cooling zone (13a) thermal oil and the cooling medium of another cooling zone (13b, 13c) haters.

6. Device according to one of the preceding claims _/ characterized by a closed circuit for at least one of the cooling means (15) of a cooling zone (13 a, 13 b, 13 c) and with a heat exchanger for recovering the heat.

7. Device according to one of the preceding claims 2 to 6, characterized in that the device comprises a plurality of sensors to the temperature of the supplied cooling medium, the temperature of the discharged cooling medium, the temperature of the cooling zone (13a, 13b, 13c) leaving free-flowing or flowable product that

Flow rate of the cooling medium (15a, 15b, 15c), the pressure of the cooling medium (15a, 15b, 15c), the

Rotational speed of the rotary drum, the speed of the free-flowing or flowable product and / or the

Throughput of free-flowing or flowable product for at least one cooling zone (13a, 13b, 13c) to measure.

8. Device according to one of the preceding claims 2 to

6, characterized in that the device comprises a plurality of actuators to the temperature of the supplied Cooling medium, the temperature of the discharged cooling medium, the temperature of the cooling zone (13a, 13b, 13c) leaving free-flowing or flowable product, the

Throughput of free-flowing or flowable product for at least one cooling zone (13a, 13b, 13c) to influence.

9. A process for producing a ferrite, characterized by the steps:

Calcining the starting materials in a rotary kiln to produce granules;

Cooling the granules by means of a device for

Cooling of a free-flowing or flowable product according to one of the claims Vo.