DE2811995A1 - Fluid bed firing - Google Patents

Description

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The invention relates to a fluidized bed furnace in which in a container with cooled or insulated walls and with an inflow base through air supplied by means of air nozzles in the inflow base from a comparatively inert material existing fluidized bed is maintained, which the fuel after heating the fluidized bed to the Zündternperatur of Fuel is supplied.

In particular, fluidized bed furnaces are used for the combustion of lumpy, pulverulent or sludge-like coal, corresponding waste ο. like Use. Through the combustion air supplied via nozzles in the inflow base on the one hand an even distribution of the air is achieved, on the other hand this air also causes a constant up and down swirling of the Bed mass, so that intensive mixing, especially in vertical leases of fuel, air and the inert material serving as a heat transfer medium. In contrast, the moving speed of the particles reaches in the horizontal direction only a very small fourth, so that it is necessary from the outset to have a uniform distribution over the fluidized bed surface bring about not only the combustion air, but also the fuel.

The state of the art includes the supply of fuel via an or several chutes from above into the fluidized bed. This type of feed is very robust and simple, but has the disadvantage of poor mixing in the horizontal direction, so that the fluidized bed must be operated with a large excess of air. Belongs to the state of the art Furthermore, the fuel is fed into the fluidized bed from the side via one or more screw feeders. Here too, however, there is mixing even more unfavorable in the horizontal direction. It gets better if in particular fine-grain fuel introduced as deeply as possible into the fluidized bed can be so that the fine particles migrate through the entire fluidized bed -! ssen and thus have enough time to burn out.

The state of the art also includes feeding via one or more Litter feeder from above onto the fluidized bed. The horizontal fuel distribution is comparatively cheap, but fine-grained fuel particles can be carried away by the flue gas flow, so that they do not

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take part in the cremation. Thus, this type of loading is only suitable for comparatively coarse-grained fuels.

The state of the art also includes the pneumatic supply of fuel via fuel nozzles evenly provided on the inflow base. With such a feed in the fluidized bed, the fuel can be distributed very evenly in the vertical and horizontal directions. Fine fuel particles must pass through the entire height of the fluidized bed, so that the burnout reaches very favorable values. The excess air can be kept low. The technical effort for this type of fuel supply however, it is considerable. The fuel, for example coal, has to be comparatively low for pneumatic transport Grains of at least 6 mm are ground and at the same time dried to less than 5% water content. The ground and dried fuel must be fed to the fuel nozzles in the inflow base via numerous individual pipelines by means of carrier air. In this pneumatic conveyor system therefore wear and clogging cannot be ruled out. There are also additional compressors to generate conveying air necessary.

The object of the invention is to provide a fluidized bed furnace with simple means to create in which it is ensured that while avoiding high excess air an even distribution of the fuel in the fluidized bed in particular also in the horizontal direction and thus a uniform burnout of all fuel particles fed to the fluidized bed is achieved can be.

This object is achieved according to the invention in that the air nozzles an air supplied in the inflow base to generate the fluidized bed the fluidized bed is imposed in at least one movement component that sets a circular movement in a horizontal plane, and the fuel is fed into the lower löreich of the fluidized bed.

One can work with downpipes which are expediently cooled. the Fuel can also be supplied via one or more screw feeders, which are located on the side of the outer walls of the fluidized bed furnace Are attached to the container and their outlet openings

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lie sufficiently deep under the surface of the fluidized bed.

The fuel is preferably introduced in one area of approx. 20% of the total fluidized bed height.

By creating a circular movement of the fluidized bed, the one or more places wherever possible quickly distributed over the cross-section of the bed.

The circling recovery of the fluidized bed can be achieved in different ways. One possibility is, for example, that the essentially vertically inflowing air which generates the fluidized bed passes through if further air is supplied off-center, a corresponding circular movement is imposed. There are several eccentric feeds for such additional air can be provided.

Another possibility is that at least those near the Container wall provided air nozzles against the vertical in the same Senses are inclined. Here, too, the flowing upwards becomes vertücal A component imposed on air that leads to a circling vortex bed. In further training * of the invention, care can be taken to ensure that that the angle of inclination changes somewhat from nozzle to nozzle, thereby contributing to further turbulence in a horizontal plane.

After the fluidized bed furnace is shut down, it goes down, of course the floating layer. the inert material in together. It also lies down on the more or less inclined nozzles in the inflow base. ISn to prevent such particles into the air nozzles and through them into the air boxes below arrive and contaminate, is in. Further development of the invention Made the suggestion that the inclined air nozzles be inclined at the outlet end are cut off, and of course the cutting direction must be guided so that the remaining part of the nozzle clears the opening itself covered at the top.

If the fluidized bed furnace is equipped with heat exchangers, so it is recommended in a further embodiment of the invention in each case individually

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the areas between the coils in a circular motion to move.

You can also use the inclined air nozzles in the inflow base Arrange in a ring, optionally with the central area through

normal upward jets are occupied. Even with this one A sufficient circular movement of the fluidized bed is achieved.

The drawings show exemplary embodiments for a more detailed explanation of the Invention in

1 shows a schematic representation of a container of a fluidized bed furnace;

FIG. 2 shows a Bell container similar to the container according to FIG. 1, but with the supply of the air which sets the fluidized bed in a circular motion takes place in a modified form;

Fig. 3 is a partial view of a delivery nozzle;

4 shows an embodiment for a fluidized bed with heat exchangers; and in

FIG. 5 shows a section along the line A-A of FIG. 4.

Ih Fig. 1, 1 denotes a container with cooled or insulated Walls is provided, which, however, are not shown in detail to simplify the figure, but are only indicated schematically as boundary walls.

Under the container 1 there is an air box 2 for the supply of the Combustion air. The nozzles are indicated at 3 and are distributed essentially evenly over the entire inflow base - of the container 1. In addition to the nozzles 3, a line 5 opens into the container 1, through which additional air is introduced. The in the container 1 through the from the nozzles 3 The fluidized bed generated by exiting air thus receives a component of movement by the additional air introduced at 5, so that a circular movement of this air and thus of the fluidized bed built up in the container 1 is created.

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At 6 the fuel supply is indicated and roan recognizes the Line 7, as the fuel through the air entering through the nozzle 3 in Schwabe and through the air entering through the nozzle 5 in a circular movement in the container 1 is forced.

The same movement can be achieved according to FIG. 2 in that the Nozzles 13 are directed obliquely into the container 11, so that the out of them exiting air has a movement component in the direction of arrow 14 and in the direction of arrow 15, which also causes a circling Fluidized bed is generated in which via the fuel supply pipe 16 of the Fuel is introduced. It should be noted that the fuel fine guidance / as deep as possible in the fluidized bed in the one shown in FIG. Way is taken.

Fig. 3 shows a partial section from an air box at 22, to which several nozzles 23 are attached, which have a corresponding inclination, for example in the manner according to FIG. 2. To prevent that when switching off the fluidized bed combustion, bed material and / or fuel material enters the nozzle 23, this is beveled as can be seen at 24 and in such a way that a protruding part 25 is formed above the opening, the the penetration of material into the nozzle 23 and thus into the air box 22 is prevented. The Austria + direction of the air is indicated by the arrow 26. This direction of movement can be divided into two components in a known manner namely once perpendicular to the air box 22 and once subdivide parallel to it. So here too there is a circular movement of the air and thus of the fluidized bed in the corresponding container.

Of course, several rows of nozzles 13 according to FIG. 2 can be next to one another be arranged, whereby the middle area does not necessarily have to be filled with inclined nozzles, but also with normal vertical, nozzles entering through the nozzle base can be occupied. This embodiment is obvious from the present description, so that a graphic representation is unnecessary.

In the embodiment according to FIG. 4, which is to be considered in connection with the embodiment according to FIG. 5, there are in the container 31 between the fuel supply lines 36a, 36b and 36c pipe slings 37 are arranged, one of which

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Coiled pipe labeled 37 is also shown in FIG. 5. These coils form parts of heat exchangers and subdivide them the container 31 in the illustrated embodiment in three sections. The fluidized bed through the coils 37 does not is disturbed, it is divided here into three parts, again being through The arrangement of, for example, correspondingly inclined nozzles 33 causes a circular movement of parts of the fluidized bed wire! Example thus the generation of three fluidized beds, as in 39, 40 and 41 is indicated. The middle nozzles are not necessarily nuts be inclined. In this case it is sufficient if sis like the nozzles 1 open vertically through the nozzle base in the container 31. Here, too, it is advisable to bevel the nozzles, as indicated in FIG. 5, in accordance with the embodiment according to FIG. 3.

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Claims (9)

Herne 1, ™ ^m MUncnen 40, FrelllgrathstraOc 19 _. . , _ _D "o _ahs Eisenacho: StraRo 17 PaS.-Anw. Herrnann-TrenUpohl DiQl -PJlVS EdUSfd ΟθίζΙθΓ Telephone: 36 20 11 Telephone: 5 Ι013 P · ϊ · 38 3012 ⁵¹⁰¹⁴ Dlpi.-lng. W. Herrmann-Trentepohl ^ ^ ⁰¹² Tolagrammansctirlft: _ Tolegramrnansciinit: Bahrpatonte He-ns PATENTANWÄLTE Bnbotzpat MOnctien ΤθΙοϊ 0B22S853 Tolex 5215300 r "1 bank accounts: 281 1 3 3 B Bavarian Association = bank MOnction 952 Dresdnor Bank AG Herna 7-520 Α 39 Postacheckkonto Dortmund C58 68-467 L · J Ref .: A 29 113 B / h. / P. Please indicate in the answer Please send a letter to: Munich March 17, 1978 STEÄG Aktiengesellschaft, Bisnarckstrasse 54, 4300 food Fluidized bed combustion Claims Fluidized bed combustion, in which in a container with cooled or insulated Walls and with an inflow base by means of air nozzles in the inflow base Air is a fluidized bed made of a comparatively inert material is maintained, to which the fuel is fed after the fluidized bed has been heated to the ignition temperature of the fuel, characterized in that it is generated by the air nozzles in the inflow base of the fluidized bed air fed into the fluidized bed in at least one in one A movement component that displaces a circular movement is imposed on the horizontal plane and the fuel is fed into the lower region of this fluidized bed. 2. Fluidized bed firing according to claim 1, characterized in that that the fuel is supplied in the range of approx. 20% of the bed height. 3. fluidized bed furnace according to claim 1 or 2, characterized in that that the motion that sets the fluidized bed into circular motion S09839 / 026Ö component of the air generating the fluidized bed through eccentric feed more air is generated. 4. fluidized bed furnace according to claim 1, 2 or 3, characterized in that at least those provided in the vicinity of the container wall Air nozzles gagen the Vertüiale are inclined in the same sense. 5. fluidized bed furnace according to claim 3, characterized in that that all air nozzles are inclined to the vertical in the same direction of rotation. 6. fluidized bed firing according to one or more of the preceding claims, characterized in that the inclined nozzles in the inflow base is arranged in a ring. 7. fluidized bed, in particular according to one or more of the claims 2 to 6, characterized in that the inclined air nozzles are cut off at an angle at the outlet end. 3. Fluidized bed firing according to one or more of the preceding claims with vertical heat exchangers arranged in the area of the fluidized bed, characterized in that the between the coils lying areas of the fluidized bed are each set in a circular motion. 9. fluidized bed furnace according to one or more of the preceding claims, characterized in that the central region of the ring arrangement is occupied with only upwardly directed air nozzles. 909839/0260