DK3243027T3

DK3243027T3 - Refractory wall, especially for an incinerator

Info

Publication number: DK3243027T3
Application number: DK16700521.4T
Authority: DK
Inventors: Tobias Kern
Original assignee: Mokesys Ag
Priority date: 2015-01-07
Filing date: 2016-01-06
Publication date: 2019-01-14
Also published as: CH710597A1; WO2016109904A1; EP3243027B1; ES2703583T3; PL3243027T3; EP3243027A1

Description

Refractory wall, in particular for a combustion furnace

The invention relates to a refractory wall, in particular for a combustion furnace, according to the preamble of claim 1.

Such refractory walls are used e.g. in combustion chambers of incineration plants. The boiler wall is often formed as a metal tube wall and as a rule consists of tubes connected by webs. The refractory protective cladding hung in front at a distance from the tube wall is intended to protect the tube wall from corrosion by flue gases. As a rule, the refractory protective cladding is formed from panels arranged in rows and columns next to and above one another. Refractory walls are also used e.g. in fluidized-bed furnaces, in which the boiler wall consists of a single metal wall of greater or lesser thickness. Here too, the boiler wall or metal wall is to be protected against corrosion.

As a rule, the panels of the protective cladding are sealed against each other up to a certain degree by various measures, in order to prevent flue gases from passing through. However, in practice this alone cannot completely prevent corrosive flue gases from getting through the protective cladding and being able to attack the boiler wall.

So-called back-ventilated wall systems address this problem in that a protective gas -generally air - is pumped through the gap between the boiler wall and the protective cladding placed in front at a distance. The gas or air is at a slight positive pressure compared with the combustion chamber, whereby the flue gases from the combustion chamber are prevented from penetrating into the wall gap and being able to attack the boiler wall or other metal parts. A generic refractory wall is described for example in document CH 699 406 A2. In this so-called back-ventilated refractory wall, the air supply or, more generally, the supply of protective gas into the gap between the boiler wall and its protective cladding is effected through a plurality of inlet openings in the boiler wall arranged distributed at the lower end of the refractory wall across the latter, which are fed from at least one supply channel, from the side of the refractory wall facing away from the fire. The inlet openings are arranged in the boiler wall in the region of continuous vertical grooves in the panels of the protective cladding, with the result that the gas or air (from the side) is primarily supplied to these grooves and can be distributed via these over the entire wall. For the better transverse distribution of the gas or air, either the panels of the protective cladding are themselves provided with transverse channels, or individual horizontal rows of panels are arranged at certain vertical distances, e.g. in each case 2-4 m, at a somewhat greater distance from the boiler wall than the other panels, with the result that horizontal transverse channels are formed, via which the gas or air can be distributed over the wall width.

The introduction of the gas or air into the gap between the boiler wall and the protective cladding described in document CH 699 406 A2 has the disadvantage, amongst other things, that for a sufficient distribution over the wall width transverse channels are required in the panels, which necessitates an additional construction effort either with respect to the panels themselves or with respect to the arrangement thereof. Furthermore, the feeding of the gas or air into the panels from the side into the grooves has not proved to be optimum. In addition, for this purpose the boiler wall has to be pierced through by inlet openings at a plurality of points.

In view of these disadvantages of this known refractory wall, the object of the invention is to improve a refractory wall of the generic type with respect to the feeding of protective gas or air into the gap between the boiler wall and the protective cladding.

This object is achieved by the refractory wall according to the invention as it is defined in the independent claim 1. Particularly advantageous developments and embodiments of the invention result from the dependent claims.

The essence of the invention is as follows: A refractory wall, in particular for a combustion furnace, comprises a boiler wall and a refractory protective cladding placed in front at a distance from it, consisting of a plurality of refractory panels arranged in rows and columns next to and above one another, which are fastened to the boiler wall in each case via at least one panel holder, wherein the refractory wall has a back-ventilated wall section, in the region of which a gap is present between the boiler wall and the protective cladding, and wherein the refractory wall comprises gas supply means for supplying a protective gas into the gap. The gas supply means comprise a gas distribution channel and at least one gas supply line for supplying protective gas into the gas distribution channel. The gas distribution channel is arranged at the lower end of the back-ventilated wall section with respect to the installation position of the refractory wall and there is no back-ventilated wall section below the gas distribution channel. The gas distribution channel is arranged on the same side as the protective cladding with respect to the boiler wall and extends across the protective cladding. The gas distribution channel is continuously over its length or at several discrete points connected in a communicating way with the gap between the part of the protective cladding situated above it and the boiler wall.

The arrangement of a gas distribution channel directly below the back-ventilated wall section and the direct feeding of the protective gas from below from the gas distribution channel into the gap between the part of the protective cladding situated above it and the boiler wall results in an optimum distribution of the protective gas in the back-ventilated wall section over the entire wall width.

According to an advantageous embodiment, the gas distribution channel is formed by a gas distribution box into which the at least one gas supply line opens. Such a gas distribution box can be easily realized and mounted rapidly.

The gas distribution box preferably has a plurality of gas outlet openings which open out into the gap between the boiler wall and the protective cladding. An optimum protective gas distribution can be achieved through the plurality of gas outlet openings.

According to another advantageous embodiment, the gas distribution channel is formed by at least one row of refractory panels arranged next to one another and at a distance from the boiler wall. This has the advantage that the gas distribution channel can be realized without special additional construction elements.

The gas distribution channel is expediently delimited on one side by the boiler wall. The gas distribution channel can be produced more simply and cost-effectively by using the existing boiler wall as gas distribution channel wall.

In the case of an advantageous design variant, the at least one gas supply line opens laterally through the boiler wall into the gas distribution channel. The gas supply line can thus be formed short.

According to a further advantageous design variant the at least one gas supply line opens from below into the gas distribution channel, wherein the at least one gas supply line is expediently passed through the boiler wall below the gas distribution channel and then runs upwards between the boiler wall and the protective cladding and opens into the gas distribution channel. This has the advantage that the place where the protective gas passes through the boiler wall can be determined independently of the position of the gas distribution channel.

The boiler wall is advantageously formed as a tube wall with tubes connected by webs.

In the region of the back-ventilated wall section above the gas distribution channel, the boiler wall expediently has no gas supply lines for supplying gas into the gap.

In the following, the invention is described in more detail with reference to embodiment examples represented in the drawing. There are shown in:

Fig. 1 - a schematic interior view of a combustion furnace with a refractory wall according to the invention,

Fig. 2 - a partial sectional view of the refractory wall along the line ll-ll of Fig. 1,

Fig. 3 - a partial sectional view of the refractory wall along the line Ill-Ill of Fig. 2,

Fig. 4 - a view of a section of the refractory wall in the direction of the arrow IV of Fig. 1,

Fig. 5 - a partial sectional view analogous to Fig. 2 of a second embodiment example of the refractory wall according to the invention,

Fig. 6 - a partial sectional view of the refractory wall along the line VI-VI of Fig. 5,

Fig. 7 - a partial sectional view of the refractory wall along the line VII-VII of Fig. 6,

Fig. 8 - a partial sectional view analogous to Fig. 2 of a third embodiment example of the refractory wall according to the invention,

Fig. 9 - a partial sectional view of the refractory wall along the line IX-IX of Fig. 8,

Fig. 10 - a partial sectional view of the refractory wall along the line X-X of Fig. 9 or Fig. 12,

Fig. 11 - a partial sectional view analogous to Fig. 2 of a fourth embodiment example of the refractory wall according to the invention and

Fig. 12 - a partial sectional view of the refractory wall along the line XII-XII of Fig. 11.

The following applies to the description below: For the purpose of clarity of the drawing, if reference numbers are indicated in a figure, but not mentioned in the directly associated part of the description, reference is made to the explanation thereof in preceding or subsequent parts of the description. Conversely, to avoid overloading the drawing, reference numbers that are less relevant for immediate understanding are not included in all the figures. For this purpose, reference is made to the respective other figures.

Position and direction terms, such as e.g. above, below, next to one another, above one another, lateral, vertical, horizontal, height and width, refer to the usual vertical position of use of the refractory wall represented in the drawing.

Fig. 1 shows schematically a combustion furnace V equipped with a refractory wall W according to the invention. The wall W is divided into an upper, back-ventilated wall section W-ι and a lower, back-filled wall section W2. Between the two wall sections W-i and W2 or at the lower end of the back-ventilated wall section W-ι runs a gas distribution channel K extending over the entire wall width, which is described in more detail below. The wall W comprises a boiler wall 1 (Fig. 2) which is not visible in Fig. 1, and a protective cladding 2 placed in front at a distance from it, which consists of a plurality of refractory panels arranged next to and above one another, in rows and columns. The panels in the back-ventilated wall section W-ι are denoted 21, while the panels of the lower wall section W2 are denoted 22. The panels 21 and 22 are for example ceramic SiC panels, preferably SiC 90 panels with an SiC content of approximately 90% in production, which are refractory up to more than 1000°C.

The boiler wall 1, continuous over the back-ventilated wall section W-ι and the backfilled wall section W2, is formed as a tube wall and consists of a plurality of tubes 11, vertical in practical use, which are held together at a distance from each other by webs 12 (see in particular Fig. 4). The tubes 11 and the webs 12 usually consist of steel. A boiler insulation 15 is attached to the side of the boiler wall 1 facing away from the protective cladding 2 (Fig. 2).

The panels 21 and 22 of the protective cladding 2 are fastened to the boiler or tube wall 1 by means of (in the example here in each case four) panel holders 13. The panel holders 13 consist of heat-resistant steel, e.g. steel no. 310 according to AISI standard or material no. 1.4845 according to DIN 17440. The panel holders 13 substantially each comprise a stud bolt welded onto a web 12 and a nut situated on the stud bolt. The panel holders 13 engage in continuous vertical grooves 21a (Fig. 4) and 22a (Fig. 10), extended inwards, of the panels 21 and 22 and determine the distance of the panels 21 and 22 to the tube wall 1. The panel holders 13 also serve to support the panels 21 and 22 in a vertical direction, wherein the panels 21 and 22 rest, with bridge elements (brackets) 21b and 22b respectively arranged (formed) thereon, on the panel holders 13. The panels 21 and 22 are to a certain extent mobile in a vertical direction, in order thus to allow thermally caused expansion and contraction movements. Vertical joints (not indicated) run between the panels 21 and 22 arranged next to one another and horizontal joints (not indicated) are situated between the panels 21 and 22 arranged above one another. The joints are sealed in a manner known per se by inlaid sealing elements and/or an overlapping formation of the panel edges.

The protective cladding 2 is arranged at a certain distance from the boiler wall or tube wall 1, with the result that in each case a gap 3 or 4 is situated between the panels 21 or 22 of the protective cladding 2 and the boiler wall 1. In the upper, back-ventilated wall section W-ι the gap 3 is empty; in the lower, back-filled wall section W2 the gap 4 is filled with a refractory casting compound. In this lower wall section W2 the continuous vertical grooves 22a of the panels 22 are also filled with the casting compound (Fig. 10).

With the exception of the above-mentioned gas distribution channel K and the construction elements associated therewith and yet to be described, in its basic structure the refractory wall according to the invention corresponds to conventional refractory walls of this type, with the result that a person skilled in the art requires no more detailed explanation.

The substantial difference of the refractory wall according to the invention compared with conventional refractory walls of this type consists of the implementation of the air or general protective gas feed into the back-ventilated wall section W-ι of the refractory wall W. According to the most essential idea of the invention, for this purpose the refractory wall is equipped with the gas distribution channel K already mentioned above, which is arranged on the same side of the boiler wall 1 as the protective cladding 2, and which extends across the width of the wall at the lower end of the back-ventilated wall section W-ι. The gas distribution channel K is connected to a protective gas or air source via lines yet to be explained, and is continuously over its length or at several discrete points in communicating connection with the gap 3 between the part of the protective cladding 2 situated above it and the boiler wall 1, with the result that air or protective gas from the gas distribution channel K can be fed from below directly into the gap 3 between the boiler wall 1 and the panels 21 of the protective cladding 2.

In the following, four embodiment examples of the refractory wall according to the invention, which differ primarily only in the formation of the gas distribution channel K and the type of protective gas supply into the gas distribution channel K, are explained in more detail. In all four embodiment examples, the remaining structure of the refractory wall is basically as already described above, with the result that it is not discussed in further detail.

In the case of the first embodiment example of the refractory wall according to the invention represented in Figures 2-4, the gas distribution channel K is formed by a gas distribution box 5 which is rectangular in cross-section, and which is arranged between the bottom row of panels 21 and the top row of panels 22 and is substantially flush with the outer surface of the protective cladding 2. On its inside the gas distribution box 5, preferably consisting of metal, is delimited by the boiler wall 1 and fastened (welded) thereto. At the upper delimitation wall of the gas distribution box 5, the latter has a plurality of gas outlet openings 51 arranged distributed over its entire length (width of the wall), which open from below into the gap 3 between the boiler wall 1 and the panels 21 of the protective cladding 2 and connect the interior space of the gas distribution box communicating with the gap 3. For the feeding of protective gas or air into the gas distribution box 5 or gas distribution channel K, preferably several gas supply lines 52 are provided, which are passed through the boiler insulation 15 and the boiler wall 1 and open out into the interior space of the gas distribution box 5. In operation the gas supply lines 52 are connected to a protective gas or air source, indicated only symbolically by the arrow Q.

The gas distribution box 5 is sealed against the panels 21 or 22 bordering the gas distribution box 5 above and below, by means of sealing elements, for example sealing cords 55.

The third embodiment example of the refractory wall according to the invention, represented in Figures 8-10, differs from the first embodiment example just described, only in the type of supply of the protective gas into the gas distribution box 5. The gas supply here is effected from below into the gas distribution box 5 by means of several gas supply lines, which each have a vertical section 53a and a substantially horizontal section 53b. The vertical sections 53a of the gas supply lines run parallel to the boiler wall 1 through a part of the back-filled wall section W2 and open from below into the gas distribution box 5 (Fig. 8). The horizontal sections 53b of the gas supply lines pass through the boiler wall 1 and the boiler insulation 15 (not shown) (Fig. 10) in a similar manner to the gas supply lines according to Fig. 2. The length of the vertical sections 53a of the gas supply lines can be several metres, as is clear e.g. from Fig. 1, where the vertical sections 53a of the gas supply lines extend as far as into the lower region of the lower, back-filled wall section W2.

Figures 5-7 show a second embodiment example of the refractory wall according to the invention, which differs from the two embodiment examples just described, primarily in the implementation of the gas distribution channel. The gas distribution channel denoted K’ is here directly integrated into the protective cladding 2 and formed between the boiler wall 1 on one side and a row of (non-back-filled) panels 23 on the other side. Towards the bottom, the gas distribution channel K’ is delimited by the top row of the back-filled panels 22 of the lower wall section W2, and the bottom row of the panels 21 of the back-ventilated wall section W-ι is attached directly above the gas distribution channel K.

The panels 23 in the region of the gas distribution channel K’ are preferably formed identical, and fastened to the boiler wall 1 in the same way as the panels 22 of the back-filled wall section W2, except that they are thinner (in the direction perpendicular to their surface). Panel holders 13 engage in continuous vertical grooves 23a (Fig. 7), extended inwards, of the panels 23 and determine the distance thereof to the tube wall 1. The panel holders 13 also serve to support the panels 23 in a vertical direction, wherein the panels 23 rest, with bridge elements (brackets) 23b (Figures 5 and 6) arranged (formed) thereon, on the panel holders 13. Unlike the panels 22 of the lower wall section W2, the panels 23 are not back-filled. They are also formed less thick and deep than the panels 21 of the back-ventilated wall section W-ι. Because the panels 23 are less thick and deep in the region of the gas distribution channel K’, their distance from the boiler wall 1 is significantly greater, with the result that between the row of panels 23 and the boiler wall 1, there is a relatively large free gap which forms the gas distribution channel K’ in which the protective gas can be distributed relatively unimpeded over the entire width of the refractory wall. Of course it is also possible to also use other, in particular even less deep, panels in the region of the gas distribution channel K’, provided that these only allow the formation of a gas distribution channel of sufficiently large cross-sectional dimensions.

The feeding of protective gas into the gas distribution channel K’ is effected from the side as in the case of the embodiment example of Figures 2-4, by means of several gas supply lines 52 passing through the boiler insulation 15 and the boiler wall 1, which open directly into the gas distribution channel K’.

The fourth embodiment example of the refractory wall according to the invention, represented in Figures 10-12, differs from the third embodiment example just described, only in the type of supply of the protective gas into the gas distribution channel K’. The gas supply here is effected in a similar manner as in the case of the second embodiment example according to Figures 8-10, from below into the gas distribution channel K’ by means of several gas supply lines, which each have a vertical section 53a and a substantially horizontal section 53b. The vertical sections 53a of the gas supply lines run parallel to the boiler wall 1 through a part of the back-filled wall section W2 and open from below into the gas distribution channel K’ (Fig. 11). The horizontal sections 53b of the gas supply lines pass through the boiler wall 1 and the boiler insulation 15 (not shown) (Fig. 10) in a similar manner to the gas supply lines 52 according to Fig. 2.

As already mentioned at the beginning, the boiler wall of the refractory wall according to the invention need not be formed as a tube wall, but can for example also be a normal metal wall on which the panel holders 13 are arranged and fastened in an analogous manner as in the case of the tube wall described above.

Claims

A refractory wall (W), in particular for a combustion furnace, with a boiler wall (1) and a refractory protective covering (2) located at a front therebetween, comprising several refractory panels (21, 22, 23), which are arranged in rows and slots adjacent to and above each other, which are in each case attached to the boiler wall (1) via at least one panel holder (13), the refractory wall (W) having a rear vented wall section (W-ι), in the area of which is a gap (3) between the boiler wall (1) and the protective lining (2) and wherein the refractory wall (W) comprises gas supply means for supplying a protective gas into the gap (3), wherein the gas supply means comprises a gas distribution channel (K; K ') and at least one gas supply line (52; 53a, 53b) for supplying protective gas to the gas distribution channel (K; K'), characterized in that the gas distribution channel (K; K ') is located at the lower end of the rear vented wall section (W -ι) relative to the mounting position of the ildfa wall (W) and there is no rear vented wall section below the gas distribution channel (K; K '), wherein the gas distribution channel (K; K') is arranged on the same side as the protective cover (2) relative to the boiler wall (1) and extends across the protective cover (2), and where the gas distribution channel (K; K ') extends over its length or at several separate points is continuously connected in a communicating manner with the gap (3) between the portion of the protective covering (2) located above it and the boiler wall (1).

Refractory wall according to claim 1, characterized in that the gas distribution channel (K) is formed by a gas distribution box (5), which the at least one gas supply line (52; 53a, 53b) opens.

Refractory wall according to claim 2, characterized in that the gas distribution box (5) has several gas outlet openings (51) which open into the space (3) between the boiler wall (1) and the protective covering (2).

Refractory wall according to claim 1, characterized in that the gas distribution channel (K ') is formed by at least one row of refractory panels (23) which are arranged side by side and at a distance from the boiler wall (1).

Refractory wall according to any one of the preceding claims, characterized in that the gas distribution channel (K; K ') is bounded on one side by the boiler wall (1).

Refractory wall according to any one of the preceding claims, characterized in that the at least one gas supply line (52) opens into the gas distribution channel (K; K ') through the boiler wall (1).

Refractory wall according to any one of claims 1-5, characterized in that the at least one gas supply line (53a, 53b) opens into the gas distribution channel (K; K ') from below.

Refractory wall according to claim 7, characterized in that the at least one gas supply line (53a, 53b) is passed through the boiler wall (1) below the gas distribution channel (K; K ') and then extends upwards between the boiler wall (1) and the protective covering (2). and opens into the gas distribution channel (K; K ').

Refractory wall according to any one of the preceding claims, characterized in that the boiler wall is formed as a pipe wall (1) with pipes (11) connected by means of connecting pieces (12).

Refractory wall according to any one of the preceding claims, characterized in that the boiler wall (1) in the region of the rear vented wall section (W-ι) above the gas distribution channel (K, K ') has no gas supply lines for supplying gas. in the gap (3).