SK151996A3 - Fluidized-bed incineration plant - Google Patents

Abstract

The invention concerns a fluidized-bed incineration plant with a vertically disposed, in particular a standing or self-supporting, cyclone precipitator for returning the bed material to the combustion chamber. The cyclone precipitator (1) is designed as part of the boiler body (2) and is thus incorporated in the support structure, finned tubular walls being used which form part of the uptake and downpipe system of the cooling system and the cyclone precipitator itself preferably having a rectangular or square cross section.

Description

a circulating fluidized bed with one or more cyclone separators for returning the bed material to the combustion chamber, consisting of the walls of a tube with longitudinal ribs, usually a standing or self-supporting structure with a steam drum and a system of riser and downpipes in which there is a cyclone with a vertical axis on the outside of the wall of the boiler body formed as a target of the cooling system, at least in part, of flow walls with longitudinal ribs.

BACKGROUND OF THE INVENTION

Such devices are known from EP-A2 0481438, wherein the front wall of the cyclone separator is connected to a return wall which is part of the riser system, the return wall being better heated only in the upper part, whereby compared to other parts of the combustion chamber, operating in the radiation area, there are temperature stresses that make it difficult to start quickly.

It is known from DE-A1-3517987 that such devices are equipped with horizontal cyclone separators. This construction is susceptible to failure in the partial load region and needs a large construction height which is again limited by the pipes used. To overcome these drawbacks, DE-A1-3640377 discloses a cyclone diversion and the use of separating beams or DE-A1-4101918 the arrangement of a cyclone within the combustion chamber, whereby heating is expected to cause difficulties in the recovery of the separated residues and the heating surfaces are poorly utilized.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the aforementioned drawbacks, to reduce the need for space and to increase its size, preferably in a self-supporting construction, by integrating it into the support part of the steam boiler structure. Furthermore, by inserting the cyclone separator into the cooling circuit of the steam boiler, there is only a slight loss of heat, so that efficiency can also be improved due to the smaller surface area. Furthermore, the invention allows shorter ramp-up times.

The invention is characterized in that the boiler drum of the boiler body is arranged on a standing pipe, usually on a plurality of standing pipes, and the standing pipe or a plurality of standing pipes is connected to the boiler body, usually in the front wall area and the front wall of the cyclone. and thus connected to the cooling circuit on the front and rear walls of the combustion device. Substantial embodiments are set forth in sub-claims 2 to 7.

Overview of the figures in the drawing

The invention is illustrated schematically by way of example in the accompanying Figs. 1 and 2.

Fig. 1 shows a front view and FIG. 2 shows a side view of a steam boiler with a circulating fluidized bed.

Examples of the invention

Fig. 1 shows a steam boiler in which the cyclone 1 is integrated into the boiler body 2 and is formed as part of a supporting structure. For this purpose, the cyclone separator consists of tube walls with longitudinal ribs, which in addition form the front wall 7 and the side walls 8.

In a preferred embodiment, the front wall 14 is formed as part of a downcomer system and thus serves to supply the combustion chamber 6, which is essentially a steam boiler riser system, with cooling water. In this sense, the side walls 8 of the cyclone separator 1 are also connected to the riser system. The immersion tube 11 of the cyclone separator 1 is fire-resistant and is suspended in the annular collection chamber 12 and is optionally held by means of conduits 13 connected to the cooling system.

The steam drum 9 of the body 2 is arranged at both ends on the upright tube 10 or on a plurality of upright tubes, the upright tubes being welded to the front wall or integrated into the front wall 7 as an example. This provides the static advantage of increasing the load capacity of the front wall or of the whole body 2, so that the construction makes it possible to increase the output of the largest steam boiler produced according to the principle of a self-supporting construction, which in particular increases the economy.

For the return of the bed material, which essentially consists of sand, the lower part of the cyclone separator 1 is in the form of a funnel, the front wall 7 being first bent in the direction of the combustion chamber 6 and only further in an embodiment formed as a wall with longitudinal ribs. downward, the final outlet of the funnel is reached by the inclined position of the side walls. The actual return line 5 to the combustion chamber (5 is effected via a siphon or an L or a dam, through which the slider is guided to return the bed material returned to the fluidized bed and finally unfolds with the fuel, burning the fuel and bed material Instead of the siphon or the L-shaped slider, a dam can be built up in the horizontal return duct, which in the event of flooding will allow the return line but will prevent the return flow to the combustion chamber 6. indicated by an arrow in the drawing if the return of the bed material is indicated by a dashed arrow.

This construction enables the economical construction of the cooling structure of the cyclone separator 1 and, in all cases, the return of the bed material into the structure of the longitudinal ribs. In this case, the collecting tank 4 is arranged as far as possible in the intersection lines of the individual tube walls (FIG. 2), the connections being made by means of obliquely arranged sleeves or pipe bends just in front of the collecting tank. In order to adapt the walls of the longitudinal ribs, in particular of the cyclone separator 1, to the requirements of the cyclone, the walls of the longitudinal ribs, possibly connected to the circulation around the hard-to-cool parts, are avoided or sometimes branched.

An essential feature of the invention is the rectangular or square design of the cyclone separator 1, thereby allowing integration into the boiler body 2. In this construction, it is possible to arrange several cyclones side by side. In this case, the lateral side walls of the funnel, for example through the branches of the branching in the partition wall 15 between the cyclones, which are necessary in all cases, continue.

Within the scope of the invention it is also possible to arrange the boiler drum 9 in the extension of the partition 15 between the cyclone separator 1 and the combustion chamber 5, whereby the downcomers after corresponding curvature form the front wall 7 and the upright tubes 10 are arranged at the ends of the boiler drum 9 outside the flue gases. unfired.

Fig. 2 shows a side view of the circulating fluidized bed return structure. Parallel arrangement of several cyclone separators can be seen with their immersion tube 11 arranged side by side, in which the waste gas is separated from the bed material, which collects in a funnel-like wall arrangement and is fed to its own return line 5. The front wall 7 is part The downcomer system, shown in dotted lines at the bottom and terminating in the collecting tanks 4, in which the liquid phase is collected from the boiler drum 9 (Fig. 1), the connections are arranged obliquely on the downcomer wall with longitudinal ribs. The collecting tanks 4 then exit into the lower funnel 14 with the inclined surfaces in the intermediate plane and thus lead to the deepest point of the steam boiler.

Claims (7)

1. A circulating fluidized bed combustion apparatus having one or more ciclone separators for recirculating the bed material to a combustion chamber formed from longitudinal ribbed tube walls, in particular with a standing or self-supporting structure and a steam drum and a riser and downpipe system, wherein the cyclone with a vertical axis on the outside of the wall of the boiler body is formed as part of a cooling system at least partly of flow walls with longitudinal ribs, characterized in that the steam boiler (9) of the boiler body (2) is arranged on a standing pipe (10) in particular on the plurality of standing tubes (10) and the plurality of tubes (10) or, optionally, the plurality of standing tubes (10) is connected to the boiler body (2), usually in the region of the front wall (7) and front wall (7) of the cyclone. 1) is formed as part of the downpipe system and thus connected to the front cooling circuit and a rear wall of the combustion chamber (6). Combustion device according to claim 1, characterized in that the collecting tanks (4) supplying the wall with the longitudinal ribs of the clone separator (1) are arranged on the penetrating edges of the walls with the longitudinal ribs and connected by inclined sockets to the walls with the longitudinal ribs. Combustion apparatus according to claim 1, characterized in that the cyclone separator (1) has a fire-resistant pipe (11) suspended in the collecting tank (12) and preferably held by means of water / steam conducting lines (13). Combustion device according to claim 2, characterized in that the funnel-shaped lower part (3) of the cyclone separator (1) is formed from top to bottom by firstly inclining the front wall (7) in one direction and further down by means of the inclined position of the side walls (8). in the other direction. The combustion apparatus according to claim 4, characterized in that the plurality of front wall tubes are bent and mainly branched to form side walls (8) of the funnel of the cyclone separator (1) and optionally a return line (5). Combustion device according to claim 1, characterized in that the inner walls (8) of the return line (5) partly form by bending and in particular branching at least one part of the separating wall from the combustion chamber (6). Combustion device according to claim 1, characterized in that the return conduit parts (5), when made as a siphon, are designed as walls with longitudinal ribs and preferably supplied with easily heatable downpipes, which in turn supply the other components of the body (2). ) water / steam boiler boilers.