METHOD AND SYSTEM FOR THE THERMAL TREATMENT OF DISPERSIBLE RAW MATERIAL

Abstract

A method for the thermal treatment of dispersible raw material may inovlve introducing raw material into a riser tube that is perfused by hot gases and thermally treating the raw material with the hot gases. Furthermore, the method may inovle feeding a fuel to the riser tube. The fuel may initially dwell in a fuel-conditioning region on a bearing face, where the fuel comes into contact with a part of the hot gas that is mixed with the raw material. Consequently, the fuel is dried and/or at least partially de-gassed and/or at least partially reacted and subsequently transferred into the riser tube.

Claims

1.-12. (canceled).

13. A method for thermal treatment of dispersible raw material, the method comprising: introducing raw material into a riser tube that is perfused by hot gases; thermally treating the raw material in the riser tube with the hot gases; feeding a fuel into a fuel-conditioning region and onto a bearing face disposed in a conditioning chamber that leads into the riser tube, wherein at least 50% of the hot gases that come into contact with the fuel is formed by a part of the hot gases that is mixed with the raw material and deflected into the conditioning chamber, whereby as a result the fuel is at least one of dried, partially or completely de-gassed, or partially or completely reacted; and transferring the fuel into the riser tube.

14. The method of claim 13 wherein the fuel is fed onto the bearing face mechanically or by gravity.

15. The method of claim 13 further comprising conveying the dried, partially or completely de-gassed, or partially or completely reacted fuel mechanically or pneumatically along the bearing face before being transferred into the riser tube.

16. The method of claim 13 further comprising setting in a targeted manner an amount of the hot gases that is mixed with the raw material and comes into contact with the fuel in the fuel-conditioning region by adding an oxygen-containing gas.

17. The method of claim 13 further comprising decelerating or completely stopping a combustion reaction of the fuel on the bearing face by using an inert material.

18. A system for thermal treatment of dispersible raw material, the system comprising: a riser tube that is perfusable by hot gases; means for introducing raw material into the riser tube; and a fuel-conditioning region that comprises means for adding fuel, a bearing face for the fuel, and means for conveying the fuel along the bearing face and transferring the fuel into the riser tube, wherein the fuel-conditioning region is connected to the riser tube such that a part of the hot gases that is mixed with the raw material reaches the fuel-conditioning region and comes into contact with the fuel, whereby the fuel is at least one of dried, partially or completely de-gassed, or partially or completely reacted.

19. The system of claim 18 wherein the means for adding the fuel comprises at least one of a spiral conveyor, a gate, a pump, a tappet, a chute, a cellular wheel sluice, or a flap system.

20. The system of claim 18 wherein the means for conveying and transferring the fuel into the riser tube are formed in a shape of at least one of: gates or tappets for mechanically conveying, or air-surge apparatuses or blowers for pneumatic conveying.

21. The system of claim 18 further comprising a propulsion jet nozzle disposed in the fuel-conditioning region for deflecting the part of the hot gases that is mixed with the raw material into the fuel-conditioning region.

22. The system of claim 18 wherein a ratio of a diameter of the riser tube to a depth of the bearing surface is in a range from 5 to 1.5. (New) The system of claim 18 wherein a ratio of a diameter of the riser tube to a depth of the bearing surface is in a range from 5 to 1.5.

23. The system of claim 18 wherein a ratio of a diameter of the riser tube to a depth of the bearing surface is in a range from 5 to 1.5. (New) The system of claim 18 wherein a ratio of a diameter of the riser tube to a depth of the bearing surface is in a range from 3 to 1.5.

24. The system of claim 18 wherein the bearing face comprises at least one of: at least two successive steps, or a table and a step that adjoins the table.

25. The system of claim 18 wherein the fuel-conditioning region comprises a conditioning chamber configured in a portion of the riser tube that is disposed so as to be oblique to a vertical, wherein the bearing face comprises an outwardly offset wall region of the riser tube.

Description

[0021] Further advantages and design embodiments of the invention will be explained in more detail by means of the following description of a few exemplary embodiments and of the drawing.

[0022] In the drawing:

[0023] FIG. 1 shows a schematic view of a system for producing cement clinker;

[0024] FIG. 2 shows a schematic view of a system for the thermal treatment of dispersible raw material, according to a first exemplary embodiment;

[0025] FIG. 3 shows a schematic view of a system for the thermal treatment of dispersible raw material, according to a second exemplary embodiment; and FIG. 4 shows a schematic view of a system for the thermal treatment of dispersible raw material, according to a third exemplary embodiment.

[0026] FIG. 1 shows a system for the production of cement clinker, having a multi-stage preheater 100 for preheating cement raw meal 101, a calcinator 102 for precalcinating the preheated cement raw meal 103, a furnace 104 for burning the precalcinated cement raw meal 105 to form cement clinker, and a cooler 106 for cooling the cement clinker. The hot gases 107 that are created in the furnace 104 perfuse initially the calcinator 102 and subsequently the preheater 100. Furthermore, cooler exhaust air 108 that is created in the cooler 106 is utilized as combustion air in the calcinator 102.

[0027] Various exemplary embodiments for the configuration of the calcinator are shown by means of FIGS. 2 to 4. However, these exemplary embodiments can also relate to further systems for the thermal treatment or the chemical reaction of dispersible raw material, such as to the reduction of ore, for example, and are therefore not limited to a calcinator.

[0028] The system for the thermal treatment of dispersible raw material that is illustrated in the FIG. 2 has a riser tube 2 that is perfused by hot gases 1, means 3 for adding the raw meal 4 (in particular preheated cement raw meal 103 of FIG. 1), and a fuel-conditioning region 5 which as a conditioning chamber is attached to the riser tube 2 and openly leads into the riser tube 2. The conditioning chamber has a bearing face 7 for fuel 11, which is formed by one table 7a and two steps 7b, 7c that adjoin the latter in the direction of the riser tube. Furthermore, means 10 for adding fuel 11, which in the exemplary embodiment illustrated comprise pendulum flaps 12 and a worm 13, are provided.

[0029] The fuel 11 is pushed onto the bearing face 7 by way of the means 10. The raw material 4 to be thermally treated is fed in a lower region of the riser tube 1 by way of the means 3. Furthermore, oxygen-containing combustion air 8 (for example cooler exhaust air 107, according to FIG. 1) may be fed to the riser tube 2 by way of means 14. The conditioning chamber 6 is connected to the riser tube 2 in such a manner that a part 1a of the hot gases 1 that are mixed with the raw material 4 in the manner of a reverse flow reaches the conditioning chamber 6, and therein comes into contact with the fuel 11 that is dwelling on the bearing face 7, said fuel 11 on account thereof being dried and/or partially de-gassed and/or at least partially reacted. After a sufficient dwell time on the table 7a, the fuel is pushed onto the step 7b in that new fuel is resupplied by way of the spiral conveyor 13. Air-surge apparatuses 15, 16 for transporting the fuel from the step 7b onto the step 7c, or for dropping the fuel from the step 7c into the riser tube 2, respectively, are provided in the region of the steps. However, blowers, gates, or tappets could also be applied. The worm 13 and the air-surge apparatuses 15, 16 by way of a controller (not illustrated in more detail) are activated in a mutually adapted manner such that the fuel dwells in the fuel-conditioning region 5 for a predefined time and therein is reacted in the desired manner.

[0030] A bunker 9 for an inert material 9a can furthermore be provided, so as to decelerate or largely bring to a stop the as yet continuing fuel reaction by covering the fuel bed with an inert material (for example sand or limestone meal), for example in the case of sudden stopping of the system.

[0031] The fuel that is dropped into the riser tube 2 is entrained by the hot gas and is further reacted or combusted, respectively. The effect of the “reverse flow”, in which the part 1a of the hot gases 1 that flow upward in the riser tube 2 reaches the conditioning chamber 6, is in this instance achieved in a particularly effective manner when the ratio of the diameter D of the riser tube 2 to the depth T of the bearing face 7 of the fuel in the fuel-conditioning region 5 is in the range of 5>D/T>1.5, preferably of 3>D/T>1.5.

[0032] FIG. 3 shows an exemplary embodiment in which the conditioning chamber 6′ again openly leads into the riser tube 2′. The means 10′ for adding the fuel are again formed by pendulum flaps 12′, 13′ and a chute 18′, such that the fuel can be added by means of gravity. While the table 7a of the bearing face 7 of the first exemplary embodiment was aligned horizontally, the table 7′a of the bearing face 7′ of the exemplary embodiment according to FIG. 2 is inclined, wherein again two steps 7′b, 7′c which here are configured horizontally are disposed adjacent to the table 7′a, wherein, however, steps with inclined bearing faces are also conceivable. The angle of inclination herein can be in the range from −45° to +50°, preferably in the range from 0 to −30°, most preferably in the range from 0 to −10°. The inclination should expediently be of a magnitude that the fuel does not slide downward in a self-acting manner.

[0033] Furthermore, means 19′ for conveying the fuel 11′ along the bearing face 7′ are provided in the exemplary embodiment illustrated, which means 19′ here are formed by a gate. Air-surge apparatuses 15′, 16′ are again provided in the region of the steps. This oblique arrangement of the table 7′a has the advantage that conveying of the fuel 11′ is facilitated. Moreover, the deflection of a part 1′a of the hot gas 1′ that is mixed with the raw material 4′ can be facilitated by this geometry of the conditioning chamber 6′. In order for this deflection to be further facilitated, propulsion jet nozzles 20′ which are aligned in such a manner that the latter induct a part of the hot gases 1′ that are blended with the raw material 4′ into the conditioning chamber 6′ are provided in the region of the conditioning chamber 6.

[0034] A particularly efficient reaction of the fuel in the region of the fuel-conditioning region 5, 5′ results when the ratio of the height H of the fuel-conditioning region to the depth T of the bearing face is between 0.5 and 2, preferably 0.75 and 1.5. If the bearing face 7, 7′, as is the case with the two exemplary embodiments, is formed by one table 7a, 7′a and at least one step 7b, 7c, 7′b, 7′c adjoining the latter, the depth t of the step is preferably 0.2 to 1 times, preferably 0.2 to 0.6 times, the depth t.sub.T of the table. A value between 0.5 and 2.5, preferably 1 and 2, has proven advantageous for the ratio of the width to the depth T of the bearing face 7, 7′.

[0035] In the case of the exemplary embodiment according to FIG. 4, the fuel-conditioning region 5″ is formed by a conditioning chamber 6″ that is disposed in a portion of the riser tube 2″ that is disposed so as to be oblique to the vertical, wherein the bearing face 7″ for the fuel is at least partially formed by an outwardly offset wall region of the riser tube 2″, said wall region in the exemplary embodiment illustrated being formed only by steps 7″b, 7″c, 7″d, 7″e that are configured so as to be inclined. Due to the inclination of the steps, simple blowers are sufficient for conveying the fuel. The means 10′ for adding the fuel 11″ here are formed by a cellular wheel sluice.

[0036] In the context of the invention, the design embodiments shown in the three exemplary embodiments, such as the design embodiment of the bearing face, for example, or the type of feeding and conveying of the fuel, can be arbitrarily combined with one another.