EP0787272B1 - Cooling surface cladding - Google Patents

Description

The invention relates to a cooling surface lining for polygonal chambers of steam generators with funnel-shaped bottom and with firing according to the principle of circulating Fluidized bed, which at least partially consists of walls stretched between collectors Fin tube walls with essentially vertical tubes, which in the Bottom area are converged bent to form a funnel, is formed.

It is known for steam generators with a polygonal combustion chamber cross section the wall surfaces with horizontally arranged or slightly rising and / or with vertically running Large lines of fin tubes. Though it is known in performing, to provide complicated pipe constructions, especially in the burner area smaller parts of the wall are bricked up and thus removed from use as a cooling surface. The funnels become screw-like, if at all, by slightly rising pipe straps lined.

From US 4,576,120 A and US 4,537,156 A, it is known for forming a combustion chamber funnel Bend the pipe walls and the different pipe lengths tiered collectors to consider. This has the disadvantage that very many collectors must be connected so that this construction for smaller funnels - so - Non-combustion chamber funnel is not used. Add to that the application the construction according to the invention is also possible with weakly heated tube walls, while the Application of the known construction for non-radiant heating surfaces (outside the Combustion chamber) circulation problems can be expected, which is reflected in part Avoid integration into the downpipe system according to the present invention with certainty leaves.

Modern furnaces, such as B. the circulating fluidized bed combustion, require in In terms of economy, a greater consideration of small ones mostly difficult to cool partial areas and a special wall formation, especially in the Funnel and / or cyclone or return part. Since bricked up wall parts the approach speed reduce, the same should be avoided if possible.

The invention has set itself the task, also external to the combustion chamber and in part Integrate small-area components in the cooling system and through special training the components and / or the lining pipes one on the circulation of the steam generator provide connected fin tube wall.

The invention is characterized in that two opposite fin tube walls in the funnel area - viewed from top to bottom - first one in its entire width funnel wall inclined to the vertical and then at least one vertical Funnel wall with decreasing width and partly inclined collectors form, and that the adjacent pipe wall and its opposite pipe wall in Funnel area - viewed from top to bottom - first with decreasing width and inclined collectors a vertical funnel wall and then with constant reduced width a side wall of the Form funnels.

Essential configurations of the invention are specified in subclaims 2-6.

The main advantages of the invention are that despite the difficult Pipe arrangement more heat exchange surfaces can be accommodated in the given space can and that the thermal stresses when starting and stopping despite faster load changes be reduced in size because all wall parts are cooled evenly, which makes the Thermal elasticity increases. The new funnel construction is also advantageous for Combustion chamber funnel suitable.

The invention is illustrated, for example and schematically, in the attached figures. 1 and 2 show in oblique plan two design variations of a funnel-shaped Bottom of a steam generator, which is entirely lined with fin tube heating surfaces are.

Fig.1 shows a combustion chamber without and Fig. 2 with bilaterally heated partition in Cut.

In Fig. 1, a funnel-shaped combustion chamber floor is shown, which through an intermediate wall is divided into two outlets. The fin tube wall 1 is in its entirety Width angled obliquely and forms the funnel wall 1 '. This funnel wall 1 'is Finally angled again towards the vertical, being down rejuvenated. This happens because the pipes that are no longer used to the outside be performed and in a collector 2, possibly under slanted connecting pieces be involved. The remaining tube wall 1 "may be continued and forms a wall of the channel 9 through which the solids are discharged. The to the Fin tube wall 1 adjoining raw wall 3 or 3 'tapers in the vertical position downwards, the surplus pipes being introduced into the collector 4 via connection piece 5 become. Then the remaining parts of the tube wall 3 are bent at an angle and form the side wall 3 "of the funnel. This tube wall is then connected to the funnel wall 1" connected in a manner known per se. Finally, the side wall 3 "in the Be bent vertically to form a further wall of the channel 9. At this Funnel construction have adjacent tube walls 1, 3 and 3 'before their first kink to form the funnel on a different vertical length, where the pipes no longer required in the subsequent inclined pipe wall part 1 'and 3 " inclined collecting chambers 4 and 2 are at least partially introduced.

Finally, two inner funnel walls 8 are provided, which are also used for cooling the funnel wall 1 "are connected in that the shorter tubes of the funnel wall 1" after a 90 ° curvature can be introduced into the funnel wall 8 and the lining represent. In this case, too, the funnel wall 8 can enter the wall of the channel 9 be transferred. With this construction, it is essential that the longer tubes of the Funnel wall 1 "in the area of the funnel wall 8 a collector 2 ', which is about half shorter than collector 2.

This measure of special funnel formation can be done in a relatively simple manner also carry out the lining of complicated fin tube wall constructions, such as in fluidized bed combustion plants with a circulating fluidized bed especially in the area of the return of the swirl material to the combustion chamber and fully line the inside surfaces with cooling surfaces. If those Heating surfaces are relatively weakly heated so they can be at least partially in the Integrate the downpipe system of the steam generator, whereby the pipes, which are connected to the collecting chambers 2 and thus arranged at the lowest are used. It is quite possible that part of the fin tube wall 1 in the riser pipe system, while another part is arranged in the down pipe system.

Fig. 1 differs from Fig. 2 not only by a changed view, but also by introducing an intermediate wall 6, so that of the tube walls enclosed space is divided. This leads to changes in the circuitry of the pipes. First, only a part of the pipes, namely the longer pipes of the partition, is the lower part of the funnel is inserted, while the shorter tubes are in a collector 4 'open at the bottom of the funnel wall 1'. The longer pipes are in the partition 6 compressed and integrated into the funnel walls 8 after spreading in such a way that the individual pipes arranged in the intermediate wall 6 are compressed can be alternately transferred into one of the two inclined funnel walls 8. Thereby the tubes of the funnel wall 8 are laid more easily compared to FIG. 1 and those in FIG. 1 referred to as shorter collectors 2 'collectors are substantially the same size as that Collector 2 and take up a large part of the tubes of the funnel wall 1 ". The lining the walls of the adjoining channel 9 can be made similarly as in FIG. 1.

Claims (7)

1. A cooling surface lining for polygonal chambers of steam generators having funnel-shaped bottoms and furnaces operating in accordance with the circulating fluidised bed principle, which lining is formed at least partially of finned tube walls extending in the manner of walls between collectors and comprising substantially vertically extending tubes which are bent in the region of the bottom so as to converge to form a funnel, characterised in that two opposing finned tube walls (1) in the funnel area - when considered from the top downwards - first of all form over their entire width a funnel wall (1') inclined with respect to the vertical and then at least one vertical funnel wall (1") with decreasing width and in part sloping collectors (2), and in that the adjacent tube wall (3) and its opposing tube wall (3') in the funnel area - when considered from the top downwards - firstly, with decreasing width and sloping collectors (4), form a vertical funnel wall and then, with a constant, reduced width, a side wall (3") of the funnel inclined with respect to the vertical.
2. A cooling surface lining according to claim 1, characterised in that the sloping collectors (2, 4) are connected to the tube wall (1, 3) by connection pieces (5) arranged at an angle to the axis of the collector.
3. A cooling surface lining according to claim 1, characterised in that the sloping collectors (2, 4) of adjacent walls are arranged at different heights.
4. A cooling surface lining according to claim 3, characterised in that the lower-lying sloping collector (2, 2') is arranged in the downpipe system of the steam generator, such that the finned tube wall (1) is associated in part with the downpipe system and in part with the ascending pipe system.
5. A cooling surface lining according to claim 1, characterised in that, when two adjacent funnel chambers (7, 7') are separated from each other by a partition wall (6) heated on both sides, the tubes of the partition wall (6) are continued alternately each in an sloping funnel wall (8) (Fig 2).
6. A cooling surface lining according to claim 1, characterised in that, when two adjacent funnel chambers without partition walls are lined, the tubes of the intersecting oblique funnel walls (8) are guided into the adjacent vertical funnel wall (1") and only the longer of the vertical tubes of the intersecting sloping funnel walls (8) are introduced into the sloping collectors (2').
7. A cooling surface lining according to claim 1, characterised in that the tube walls (1, 3, 3') exhibit different lengths in their vertical lengthwise extension prior to the first bend and are then bent alternately by obtuse angles into an inclined position or a vertical position, wherein the tubes no longer needed in the adjacent wall portion are at least in part introduced into sloping collectors (2 or 4).

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