EP3447377B1 - Heat exchanger with protection system, and method for setting up a protection system for heat exchanger - Google Patents

Description

State of the art

The invention relates to a heat exchanger with a protection system for preventing the contact of flames, embers and pollutants arising in a combustion process with the heat exchanger according to the preamble of the preamble of claim 1 and a method for building up such a protection system according to the preamble of the preamble of the claims 7 or 8. A generic heat exchanger and a generic method are for example WO 2015/187007 A1 known.

When using heat exchangers, the energy of a first medium is transferred to a second medium with or without a phase change, without the two media being in direct contact or touching. The energy exchange takes place via the heat exchanger.

The combustion temperatures in incineration plants are often over 1000 ° C. This often leads to corrosion on the heat exchangers due to flue gases. In order to extend the service life of the heat exchanger, the side of the heat exchanger facing the combustion chamber is protected by pipe wall cladding.

A known pipe wall cladding has a heat shield brick and a device for cladding the combustion chamber wall with the heat shield bricks. The device consists of a support structure and a fastening element for attaching the heat shield stones to the support structure. The heat shield stones have fastening grooves on, in which the fastener fastened to the support structure engages, whereby the heat shield stones are held securely on the support structure. The heat shield brick has a hot side, which is arranged during assembly in such a way that it faces the hot medium. The hot side is made of a high temperature resistant material. In addition, a damping insert is arranged integrally in or on the heat shield brick, which is attached outside the hot side. The damping insert consists of a ceramic material, in particular a ceramic fiber material, which is firmly connected to the base material of the heat shield brick as a fabric mat. In addition to high temperatures, the operation of incineration plants also creates vibrations and / or shocks. By arranging the damping insert on the back and on the sides of the heat shield stones, the vibrations and / or shocks between the heat shield stone and the combustion chamber wall and between the individual stones are damped. However, should a heat shield stone break or be damaged, the integral connection of the heat-resistant ceramic and the fiber material of the damping insert prevents the fragments from falling out ( WO 2001/61250 A1 ).

Also known is a refractory plate for the protective covering of a pipe wall covering, the pipes of which are connected via webs. The refractory plate has a front side and a rear side, facing the tubes in the assembled state, which has at least two partially cylindrical recesses and a plate groove connecting them. The plate groove is designed to receive a first plate holder with a cross-sectional profile tapering towards the back of the plate to a slot width D1 and has a second longitudinal extension region with a wider cross-sectional profile for the introduction of this first plate holder. In order to achieve a universal plate construction that can be used independently of the pipe wall inclination, a holding element is inserted in the second longitudinal extension area of the plate groove, from the upper side of which, facing away from the groove base, at least one undercut recess for receiving a second plate holder. ( DE 10 2009 024 128 B3 ).

Also known is an anchoring device for steel slabs covering stone slabs, which consists of a holding part and a holding bolt which penetrates it and engages in the stone slab. The holding part is on the steel pipes connecting pipe fin attached. To achieve a simpler assembly and a more universal use of the anchoring device, the holding part consists of a vertical web that can be fastened to the tubular fin and a horizontal tab that is arranged on the end of the vertical web that is remote from the tubular fin and receives the retaining bolt. The vertical web and the horizontal flap are designed to be resistant to bending and connected to one another. ( DE 198 04 311 A1 ).

Furthermore, a support tab for plates for cladding fin tubes and a fin tube wall of a steam generator provided with such tabs is known, which comprises a support part made of flat material under each plate and an essentially cylindrical foot part connected to the support part. The shape and dimensions of the foot section are designed so that the bracket can be attached to the fin tube wall by means of stud welding. ( DE 41 08 754 A1 ).

Another pipe wall cladding consists of brackets, tiles, spacers, felt and concrete. The geometry of the holder is similar to a bolt with a bolt head. The holders are welded to the heat exchanger with the long cylindrical end. The later distance of the tiles to the heat exchanger is determined by the length of the holder. The tiles, which have a connecting groove on their side facing the heat exchanger, are pushed onto the holder with the bolt head-like end. For the step of pushing on the tiles, insertion openings are optionally used in the middle of the connecting grooves. Furthermore, the tiles have a reinforcement in the area of the connecting groove. The material from which the tiles are made is nitride-bonded silicon carbide. If a horizontal row of tiles is pushed onto the holder or mounted on the holder, these tiles are fixed on the holder with wedges. For this purpose, the wedges are inserted into the connecting groove up to the head part of the holder and act between the head of the holder and the inner wall of the connecting groove opposite the head, so that the head of the holder is pressed against the groove opening. Before the next horizontal row of tiles is pushed onto the brackets, the spacers must be placed on the corners of the tile or in the crossing points of the cross joints. These serve to align the tiles horizontally and vertically. The spacers are made of high-temperature fibers and plastic. Through the described installation of the tiles arise horizontally by the spacers and vertically by the spacing of the holder gaps between the adjacent tiles. To close this gap, felt is applied horizontally and vertically around the tiles. If the entire height of the heat exchanger is covered with tiles, the cavity created between the tiles and the heat exchanger is poured with flow concrete. When the incinerator is started up for the first time, the plastic part of the part of the spacers protruding into the combustion chamber burns and the high-temperature fibers remain. ( WO 2015/187007 A1 )

Since residues such as e.g. B. ash, these residues can accumulate on the high-temperature fibers protruding into the combustion chamber. These deposits have an insulating effect on the pipe wall cladding. As a result, the accumulation of ash lowers the efficiency of the incineration plant. The cleaning of the accumulated ash results in a high maintenance effort.

Furthermore, the spacers are always arranged at the intersecting point of the joints, which means that the tiles can be balanced in all directions, but this results in high installation stresses, which often break the spacers and make it more difficult to compensate for deviations in the heat exchanger wall.

Another disadvantage is that the brackets used are special parts and therefore require a special production for the pipe wall cladding, which results in high unit costs. In addition, it is difficult to vary the distance between the tiles and the heat exchanger, since the distance is determined by the length of the holder. Since the holders are attached to the heat exchangers by means of welding and these holders are not standard parts, special welding receptacles have to be developed for these holders and additional welding process tests have to be carried out, which entails additional effort and costs. Another disadvantage of the holder is that its head is flattened, which means that the holder has to be welded on orthogonally and the flattened head horizontally, so that the plates can be slid on and hold easily. Thus, the effort of installing the holder is very high.

The pipe wall cladding described has yet another disadvantage which arises from the fixing of the tiles by means of the wedges described. Because the wedges are inserted into the connecting groove, the connecting groove can only be filled completely poorly with poured concrete in the later step of pouring. This results in voids in the pipe wall cladding, which have an insulating effect and thus reduce the efficiency.

The method of constructing the pipe wall cladding also has disadvantages. On the one hand, the pipe protection wall is completely built up before casting and therefore does not offer the possibility of controlling the casting process. Furthermore, during the construction of the tiled wall, the spacers must always be attached prior to grouting, as these are necessary for the horizontal and vertical alignment of the tiles, which has the disadvantage that the pouring out of the cavity leads to contamination with concrete residues on the spacers or in the area where the felt is to be attached later. Such contamination can later lead to expansion problems in the combustion process of the system, which can result in damage to the pipe bulkhead.

The object of the invention is therefore to change the known pipe wall cladding in such a way that they are more economical to manufacture and construct and have a higher process reliability during casting, so that no voids are formed and maximum efficiency is thus achieved.

The invention and its advantages

The heat exchanger according to the invention with a protection system with the characterizing features of claim 1 has the advantage that the spacer does not protrude into the area of the combustion chamber and thus no residues of high-temperature fibers remain after firing the combustion chamber. This is achieved in that the spacer is inserted into the groove of the ceramic plate and has a circumferential bead, the height of which Gap width determined between the ceramic plates. Since the width of the bead is smaller than the wall thickness of the ceramic plate in the area of the groove, the spacer does not protrude into the combustion chamber of the incinerator at any time.

According to an advantageous embodiment of the invention in this regard, the spacer is a hollow body which has openings at the two ends which protrude into the ceramic plates arranged one above the other. This ensures that the poured concrete can spread unhindered along the groove of the ceramic slabs in the area of the spacers. This prevents cavities from forming in the areas of the grooves that have an insulating effect and reduce the efficiency of the incineration plant.

According to an additional advantageous embodiment of the invention, the hollow spacer additionally has a vertical gap with an approximately identical width to the opening of the groove of the ceramic plate in the region where the opening of the groove of the ceramic plate is in the assembled state. This results in an even better filling of the groove when pouring with flow concrete, since the concrete can now flow into the groove in the area of the spacers without any obstacles. This further reduces the risk of possible cavities and the associated reduction in efficiency.

According to another advantageous embodiment of the invention, standard components that can be ordered are used for fastening the ceramic plates and no further processing is required for their use or processing. Standard studs already have a welding procedure test so that the costs can be saved. Furthermore, you can order the bolts in different lengths without having to make them separately. In addition, special designs of welding head receptacles can be saved as there are standard welding systems.

According to an advantageous embodiment of the invention in this regard, the head pin must be welded orthogonal to the surface of the heat exchanger, but the head pin can be rotated around its own axis as desired. This allows the head bolts to be mounted on the heat exchanger much faster.

An additional advantageous embodiment of the invention consists in that clamping springs are arranged between two horizontally adjacent ceramic plates. This decouples the horizontal from the vertical alignment of the ceramic plates. With the help of the clamping springs, only the horizontal alignment takes place. The spacers are used exclusively for vertical alignment. Since the wire of the clamping springs is very thin, the wire burns up when the incinerator is heated up and no residues of the incineration process, such as e.g. B. ash.

According to another advantageous embodiment of the invention, wedges are used to fix the ceramic plates pushed onto the head bolts. To do this, the wedges are inserted between the pipe wall and the ceramic plates. This has the advantage over the prior art that the groove of the ceramic plate remains free and can be easily filled with flow concrete. Furthermore, each individual ceramic plate can be aligned individually.

The method according to the invention with the features of claim 7 enables a very safe assembly at a lower cost of the protective wall, since the process can be controlled very well. This is made possible by the use of standardized headed studs, which are welded to the heat exchanger very quickly using a stud welding process. Furthermore, any horizontal row of ceramic plates can be aligned very quickly by using clamping springs. Since the horizontal and vertical balancing of the plates is done separately, this can be done more quickly since the balancing is not as complex as when using only the spacers. Each row can therefore be cast separately for better control of the casting process.

In contrast to the method according to claim 7, in the inventive method according to claim 8, the ceramic plates with spacers, sealants and optionally clamping springs and wedges are first installed and then the space between the heat exchanger and ceramic plates is filled with flow concrete. This enables the protective system to be installed very quickly. The spacer also enables a very quick, yet exact installation of the ceramic plates on top of each other thanks to its simple and intuitive plug-in function. However, in this method the process control during the casting is not given as in the method with the features of claim 7.

drawing

Fig. 1a

einen erfindungsgemäßen Wärmetauscher mit einem Schutzsystem in der Vorderansicht,

Fig. 1b

den Wärmetauscher mit Schutzsystem aus Fig. 1a in der Seitenansicht,

Fig. 1c

den Wärmetauscher mit Schutzsystem aus Fig. 1a in der Draufsicht,

Fig. 2a

einen erfindungsgemäßen Abstandshalter in der Vorderansicht,

Fig. 2b

den Abstandshalter aus Fig. 2a in der Seitenansicht,

Fig. 2c

den Abstandshalter aus Fig. 2a in der Draufsicht,

Fig. 3a

eine Keramikplatte mit einer in einem verstärkten Bereich angeordneten Nut mit Einschuböffnung,

Fig. 3b

die Keramikplatte aus Fig. 3a in einer isometrischen Darstellung,

Fig. 3c

die Keramikplatte aus Fig. 3a in der Draufsicht,

Fig. 4a

eine Klemmfeder zum Verbinden zweier horizontal benachbarter Keramikplatten in der Vorderansicht und

Fig. 4b

die Klemmfeder aus Fig. 4a in einer isometrischen Darstellung.

A preferred embodiment of the object according to the invention is shown in the drawings and is explained in more detail below. Show it

Fig. 1a

a heat exchanger according to the invention with a protection system in the front view,

Fig. 1b

the heat exchanger with protection system Fig. 1a in the side view,

Fig. 1c

the heat exchanger with protection system Fig. 1a in the top view,

Fig. 2a

a spacer according to the invention in front view,

Fig. 2b

the spacer Fig. 2a in the side view,

Fig. 2c

the spacer Fig. 2a in the top view,

Fig. 3a

a ceramic plate with a groove arranged in a reinforced area with an insertion opening,

Fig. 3b

the ceramic plate Fig. 3a in an isometric representation,

Fig. 3c

the ceramic plate Fig. 3a in the top view,

Fig. 4a

a clamping spring for connecting two horizontally adjacent ceramic plates in the front view and

Fig. 4b

the clamping spring Fig. 4a in an isometric representation.

Description of the embodiment

The 1a to 1c show schematically the front view, the side view and the top view of a heat exchanger (7) according to the invention with a protection system, the protection system consisting of ceramic plates 1, head bolts 2, spacers 3, clamping springs 4, sealing means 5 and 6 flow concrete. How out 1a and 1b to recognize, the protection system is arranged in front of the heat exchanger 7. At the heat exchanger 7, consisting of tubes 8 and webs 9, which connect the tubes 8 to one another, the head bolts 2 are welded to the webs 9 by means of a stud welding process. The head bolts 2 determine the wall thickness of the protection system along their length and are generally 35 mm long. The longer the head bolts 2, the thicker the protection system. The head bolts 2, consisting of rustproof and heat-resistant stainless steel, are standardized purchase parts and, thanks to their arrangement, ensure an even distribution of the load of the protection system on the heat exchanger 7.

The ceramic plates 1 are pushed onto these headed bolts 2 by means of a groove 10 arranged on the ceramic plates 1 ( Fig. 1c such as 3a to 3c ). The groove 10 is located in a reinforced area 11 of the ceramic plate 1 so that the strength of the ceramic plate 1 is not reduced or a predetermined breaking point is generated. For each ceramic plate 1 two supporting head bolts 2 are provided, as in Fig. 1b can be seen. In addition, in the present example there are optional insertion openings 12, as in FIGS 3a and 3c to recognize, arranged in the middle of the groove 10 in order to facilitate the pushing on of the ceramic plates 1. The ceramic plates 1 consist of nitride-bonded silicon carbide and are sintered and then fired so that the porous surface closes after sintering and a smooth surface is formed. The ceramic plates 1 thus have a very high oxidation resistance with a very good thermal conductivity.

The ceramic plates 1 are pushed on horizontally row by row, as in Fig. 1c shown. For the horizontal alignment of the ceramic plates 1 are used in the 4a and 4b shown clamping springs 4, which are inserted horizontally between the ceramic plates 1. The clamping springs 4 consist of spring wire, which is shaped in such a way that four clamping surfaces 13, two for each of the horizontally adjacent ceramic plates 1, arise. The wire of the clamping springs 4 is self-contained, the two ends being connected by means of a tungsten gas welding process. The distance a between two clamping springs 4 resting on one and the same ceramic plate 1 is equal to or smaller than the thickness b of the ceramic plate 1. The two clamping surfaces 13 resting on a ceramic plate 1 are starting from from the central web 14 connecting them, in the direction of the ceramic plate 1, that is to say inclined towards one another, in order to enable a balancing with a good clamping effect. Although these clamping springs 4 protrude into the combustion chamber 15 of the combustion system during assembly, they are made of a corresponding material and have a small wall thickness, which leads to the parts of the clamping springs 4 protruding into the combustion chamber 15 burning up when the combustion system is operated.

The sealing means 5, which seals the gaps between the ceramic plates 1, is located between the ceramic plates 1. Another important task of the sealing means 5 is to absorb or compensate for the expansion of the ceramic plates 1 by the heat generated during the combustion process. This sealing means 5 consists of heat-resistant bio-soluble paper and is arranged on each peripheral edge of the ceramic plates 1.

For further fixation of the ceramic plates 1, wedges (not shown in the figures) are used, which are inserted between the heat exchanger 7 and the ceramic plates 1, so that the aligned ceramic plates 1 cannot slip or shift during casting.

If a horizontal row with ceramic plates 1 is completely pushed on and fixed, the space between heat exchanger 7 and ceramic plates 1 is then cast in the method chosen in the present example and the spacers 3 are inserted into the grooves 10 of the upper ends of the ceramic plates 1. A spacer 3 according to the invention is in the 2a to 2c shown. The spacers 3 are hollow bodies which have openings 16 at their upper and lower ends which are inserted into the ceramic plates 1 and also a vertical gap 17 which corresponds in width to the opening width of the groove 10 in the ceramic plate 1 and is in the inserted state is located in the region of the opening of the groove 10 of the ceramic plate 1. Furthermore, the spacer 3 has a circumferential bead 18 which determines the subsequent distance or the gap between the ceramic plates 1, which is 5 mm in the exemplary embodiment. The spacer 3 is inserted deep into the groove 10 of the ceramic plate 1 until the circumferential bead 18 of the spacer 3 rests on the top of the ceramic plate 1. If the sealing means 5 reaches as far as the groove 10, this is pressed together by the overlying ceramic plates 1 on the spacer 3 in the region of the bead 18, so that the ceramic plates 1 are also sealed in this region. Chamfers 19 are machined at its upper and lower opening 16 in order to facilitate insertion into the ceramic plates 1. The spacers 3 consist of polypropylene and high-temperature fibers, the plastic burning and gasifying when the combustion system is started up, and only the structure of the high-temperature fiber remains between the ceramic plates 1. Due to the design of the spacers 3 as hollow bodies, they do not interfere with pouring with the flow concrete 6. The flow concrete 6 can flow unhindered through the spacers 3 within the groove 10 of the ceramic plates 1 or the flow concrete 6 can be well vented during pouring without voids Form behind the ceramic plates 1.

If spacers 3 have been inserted into the grooves 10 of all ceramic plates 1 of a horizontal row, the next row of ceramic plates 1 is plugged onto the headed bolts 2, the ceramic plates 1 with their lower groove openings being pushed onto the spacers 3. The ceramic plates 1 are then tared and back-poured. These steps are repeated until the entire heat exchanger 7 is provided with the protection system.

List of reference numbers

1

Ceramic plate

2nd

Head bolt

3rd

Spacers

4th

Clamping spring

5

Sealant

6

Flow concrete

7

Heat exchanger

8th

Pipe of the heat exchanger

9

Web of the heat exchanger

10th

Groove of the ceramic plate

11

reinforced area

12th

Slot

13

Clamping surface

14

Middle web of the clamping spring

15

Combustion chamber

16

Opening the spacers

17th

vertical gap of the spacers

18th

bead

19th

Chamfer the spacer

a

Distance between the clamping surfaces

b

Thickness of the ceramic plates

Claims (8)

1. Heat exchanger (7) with a protection system, consisting of ceramic plates (1), head bolts (2), spacers (3) and sealing means (5), wherein the head bolts (2) are disposed on the heat exchanger (7), the ceramic plates (1) have a continuous vertical groove (10) on their surface facing the heat exchanger (7) in an area (11) enhanced in its thickness and a plurality of ceramic plates (1) side by side to and one above the other with their groove (10) are pushed onto the head bolts (2) and the sealing means (5) and the spacers (3) to align the ceramic plates (1) are disposed between ceramic plates (1) disposed one above the other and the space between the heat exchanger (7) and the ceramic plates (1) is filled with fluid concrete (6),
   characterised in that,
   the spacers (3) have an outer contour that can be inserted into the groove (10) of the ceramic plate (1) and on this outer contour have a encircling bead (18) that is horizontal in their mounted position and that is smaller in its width extending in the direction of the thickness of the ceramic plate (1) than the thickness of the ceramic plate (1) in the area of the groove (10), wherein the bead (18) rests with its underside on the upper edge of the ceramic plate (1) and the ceramic plate (1) disposed above this ceramic plate (1) rests with its underside on the upper side of the bead (18), so that a gap is formed between the ceramic plates (1) disposed above one another.
2. Heat exchanger in accordance with Claim 1,
   characterised in that,
   the spacers (3) are hollow bodies, that have openings (16) at their two ends, that can be inserted into the groove (10) of the ceramic plates (1).
3. Heat exchanger in accordance with Claim 1 or 2,
   characterised in that,
   the spacers (3) have a vertical gap (17) that corresponds to the width of the opening of the groove (10) in the ceramic plate (1).
4. Heat exchanger in accordance with one of the Claims 1 to 3,
   characterised in that,
   standard parts that are welded onto the heat exchanger (7) are used as head bolts (2).
5. Heat exchanger in accordance with one of the Claims 1 to 4,
   characterised in that,
   clamping springs (4) are disposed between the edges of the ceramic plates (1) to align two ceramic plates (1) disposed horizontally side by side to the other.
6. Heat exchanger in accordance with one of the Claims 1 to 5,
   characterised in that,
   wedges are disposed between the heat exchanger (7) and the ceramic plate (1) to align the ceramic plates (1) disposed side by side to and one above the other.
7. Method for constructing a protective system for a heat exchanger (7) with a protection system, consisting of ceramic plates (1), head bolts (2), spacers (3) and sealing means (5), wherein the head bolts (2) are first fastened to the heat exchanger (7), after which the ceramic plates (1) side by side to and one above the other are pushed onto the head bolts (2) by means of a continuous vertical groove (10) on the surface facing the heat exchanger (7) in an area (11) of the ceramic plate (1) enhanced in its thickness and the sealing means (5) for sealing and the spacers (3) for aligning the ceramic plates (1) are disposed between the edges positioned one above the other of two ceramic plates (1) and the space between the heat exchanger (7) and the ceramic plates (1) is filled with fluid concrete (6),
   characterised in that,
   the spacers (3) have an outer contour that can be inserted into the groove (10) of the ceramic plate (1) and on this outer contour have a encircling bead (18) that is smaller in its width extending in the direction of the thickness of the ceramic plate (1) than the thickness of the ceramic plate (1) in the area of the groove, and the spacers (3) are inserted into the grooves (10) of the ceramic plates (1) mounted in advance in a horizontal row, wherein the bead (18) rests with its underside on the upper edge of the ceramic plate (1) so that it is then cast, that then the next row of ceramic plates (1) is mounted, wherein every ceramic plate (1) with its groove (10) is pushed onto the spacers (3), so that its underside rests on the upper side of the bead (18), so that a gap is formed between the ceramic plates (1) disposed one above the other and the intermediate space between the heat exchanger (7) and the ceramic plates (1) after at most every horizontal row is filled with fluid concrete (6).
8. Method for constructing a protective system for a heat exchanger (7) with a protection system, consisting of ceramic plates (1), head bolts (2), spacers (3) and sealing means (5), wherein the head bolts (2) are first fastened to the heat exchanger (7), after which the ceramic plates (1) side by side to and one above the other are pushed onto the head bolts (2) by means of a continuous vertical groove (10) on the surface facing the heat exchanger (7) in an area (11) of the ceramic plate (1) enhanced in its thickness and the sealing means (5) for sealing and the spacers (3) for aligning the ceramic plates (1) are disposed between the edges positioned one above the other of two ceramic plates (1) and the space between the heat exchanger (7) and the ceramic plates (1) is filled with fluid concrete (6),
   characterised in that,
   the spacers (3) have an outer contour that can be inserted into the groove (10) of the ceramic plate (1) and on this outer contour have a encircling bead (18) that is smaller in its width extending in the direction of the thickness of the ceramic plate (1) than the thickness of the ceramic plate (1) in the area of the groove, and the spacers (3) are inserted into the grooves (10) of the ceramic plates (1) mounted in advance in a horizontal row, wherein the bead (18) rests with its underside on the upper edge of the ceramic plate (1), that then the next row of ceramic plates (1) is mounted, wherein every ceramic plate (1) with its groove (10) is pushed onto the spacers (3), so that its underside rests on the upper side of the bead (18), so that a gap is formed between the ceramic plates (1) disposed one above the other and finally the intermediate space between the heat exchanger (7) and the ceramic plates (1) is filled with fluid concrete (6).

Images