EP1856468A2

EP1856468A2 - Refractory tile, in particular for gasifier

Info

Publication number: EP1856468A2
Application number: EP06726033A
Authority: EP
Inventors: Christian Claude His; Thibault Pierre Paul Champion; Franceline Marguerite Louise Villermaux
Original assignee: Saint Gobain Centre de Recherche et dEtudes Europeen SAS
Current assignee: Saint Gobain Centre de Recherche et dEtudes Europeen SAS
Priority date: 2005-03-07
Filing date: 2006-03-06
Publication date: 2007-11-21
Also published as: KR20070116075A; US8601959B2; US20080163806A1; CA2600228A1; FR2882812B1; KR101246593B1; RU2007136379A; WO2006095081A3; WO2006095081A2; FR2882812A1; BRPI0608346A2; CN100578128C; JP5043821B2; ZA200707706B; JP2008531978A; CN101137880A; RU2395050C2

Abstract

The invention concerns a refractory tile having two aligned fixing points, any two adjacent fixing points of the alignment being spaced apart by a constant distance A, first (44) and last (46) fixing points of the alignment being remote, in the direction of the alignment, by distancesa1 and a2 from the first (40) and second (42) edges of the tile extending proximate the first (44) and last (46) fixing points, respectively. The tile is characterized in that 0 < A - (A1+a2). The invention is applicable to gasifiers.

Description

Refractory tile, especially for qazéificateur

The invention relates to a refractory tile intended to be fixed to a wall of a reactor, in particular to protect this wall from heat.

Refractory tiles are used to coat the walls of combustion chamber tubes of household waste or biomass incineration boilers. The tubes are conventionally substantially vertical and interconnected by transverse bars. The tiles form a refractory lining protecting the tubes from physical contact with the materials being burned and with the fumes resulting from this combustion. The small thickness of the tiles makes it easier to transfer heat from the reactor to the fluid flowing in the tubes of the boiler.

Water circulates in the tubes to recover some of the heat released during incineration. Close contact between the tiles and the tubes is therefore sought. For this purpose, as described for example in EP 1 032 790, the rear face of the tiles conventionally presents hemi-cylindrical channels shaped to each receive a tube of the wall of tubes. A thin layer of liquid mortar can also be placed behind the tiles to limit the volume of voids between the tiles and the tubes, and thus improve the heat exchange.

The use of floating tiles attached to the wall gives the tiles some mobility relative to each other. For this purpose, the tiles may for example be freely attached to the hooks fixed in the middle of the bars and the tiles may be spaced from each other by a few millimeters. The protective coating can thus adapt to the dimensional variations of the tiles during the thermal cycles. The reliability of the coating is thus improved.

The expansion space between two adjacent tiles is generally filled by means of a flexible mortar so as to ensure the tightness of the coating. Flexible mortar expansion joints are vulnerable areas and their length must be minimized. Classically, each tile therefore extends over several tubes. To facilitate the placement of the coating, the dimensions of the tiles must however be limited. For example, the tiles described in EP 032790 extend over three tubes. They comprise two notches extending on each side of the central channel and intended to receive fasteners. Two types of mounting are possible with the system described in EP 1 032 790.

According to the first type of assembly, the hooks are mounted so as to allow the tiles to be staggered in the vertical or horizontal direction. Such an assembly makes it possible to avoid an alignment of the vertical or horizontal joints according to the chosen configuration. In practice, this type of assembly is however complex and source of error. Moreover, it is long to achieve and its cost is high.

According to the second type of assembly, the hooks are arranged in vertical and horizontal lines. The configuration of the tiles however implies a variable spacing of the lines of hooks which leads to an alignment of the vertical and horizontal joints. However, the inventors have found that such an alignment decreases the durability of the joints, and therefore of the coating.

Moreover, there are sometimes obstacles, for example formed by thermocouples passages, which require a modification of the assembly. In particular, it may be necessary to shift one or more rows of hooks, which is an expensive operation. It is also possible to cut one or more tiles. But a cut inevitably weakens the part in use.

There is therefore a need for a refractory lining having refractory tiles that is easy to implement, especially to take into account the presence of obstacles, and has improved reliability.

The object of the invention is to satisfy this need.

According to the invention, this object is achieved by means of a refractory tile, in particular intended to protect an internal wall of a gasifier reactor, said tile having an alignment of at least two fixing points, two adjacent fixing points any of said alignment being spaced a constant distance A, the first and last fixing points of said alignment being spaced, in the direction of said alignment, by distances α-i and α ₂ of first and second edges of said tile extending near said first and last attachment points, respectively. The tile according to the invention is remarkable in that 0 <A - (αi + α ₂ ).

When the distance D = A - (α-ι + α ₂ ) corresponds to the width eι of the vertical expansion joints, the fasteners of a row of tiles are then regularly spaced from the length A. In other words, the horizontal spacing between two side-by-side fasteners is the same that these organs are intended to support the same tile or two adjacent tiles. It is therefore possible to horizontally offset a tile row of distance A or any multiple of this distance. Likewise, when the distance D corresponds to the width e _h of the horizontal expansion joints, it is possible to offset vertically a row of tiles by the distance separating two superimposed fixing points of the tile, or any multiple thereof. distance.

The adaptation of the assembly of the tiles to take into account the presence of an obstacle can thus result from a simple horizontal and / or vertical shift of the tiles. In addition, it is possible to shift the tiles of two superposed rows and / or two adjacent columns so as to eliminate any continuous alignment of the vertical and / or horizontal joints. The reliability of the joints, and therefore the coating, is advantageously improved. Preferably, the tile according to the invention also has one or more of the following optional features:

- In a service position of the tile, that is to say in a position where it is fixed on a wall, said alignment is vertical or horizontal.

The attachment points are shaped to allow a floating attachment of the tile, that is to say with a functional game, if possible in the three dimensions of the space. Preferably the attachment points are notches.

- A - (αi + α ₂ ) is between 2 and 10 millimeters. Advantageously, an expansion space can thus be provided between two tiles.

The tile has at least one notch opening exclusively on a rear face of said tile.

The tile comprises at least one notch opening through a lower opening on a lower edge of said tile, and at least one tongue adapted to be introduced, at least in part, by a lower opening of a notch of another identical tile. Preferably, the tile has as many said tabs that it has notches.

The tile has, on a rear face, at least one spacer preferably extending over only a portion of the height H of the tile. Preferably the spacer does not extend to the lower edge of said rear face. Upper and lower slices of the tile have upper and lower lips extending respectively in extension of front and rear faces of the tile.

The tile has a generally curved shape, preferably slightly cylindrical.

- The tile is a material having at least 60%, in percentages by weight, of non-siliceous oxides and / or less than 1% by weight of silica (SiO ₂ ).

The invention also relates to a refractory lining, in particular for protecting the internal wall of a reactor from a gasifier, comprising an assembly of refractory tiles secured to fasteners fixed to a wall, which is remarkable in that said lining comprises least one tile according to the invention.

Preferably, the refractory lining according to the invention also has one or more of the following optional features: at least one tile of the assembly has a horizontal alignment of at least two attachment points, any two adjacent attachment points of the alignment being spaced a constant distance A, the first and last attachment points of said alignment being spaced, in the horizontal direction, by distances α ₁ and α ₂ of right and left edges of said tile, respectively, such that 0 <A - (0M + 0C2), and said tile being spaced apart from at least one tile disposed to its right or to its left by a distance β | equal to A - (αi + α ₂ ).

A discontinuity of the vertical joints is then possible by horizontal shift of a row of tiles relative to another adjacent row.

At least one tile has a vertical alignment of at least two fixing points, any two adjacent fixing points of the alignment being spaced a constant distance A ', the first and last fixing points of said alignment being spaced apart, in the vertical direction, by distances Ot ₁ 'and Ct ₂ ' of upper and lower edges of said tile, respectively, such that 0 <A '- (α-i' + α ₂ '), and said tile being removed from at least one tile disposed above or below it by a distance e _h equal to A '- (αi' + α ₂ '). A discontinuity of the horizontal joints is then possible by vertical offset of a "column" of tiles compared to another adjacent tile column.

- The distances e _t and e _h are substantially equal, and preferably are between 2 and 10 mm. - A refractory concrete autocoulable is arranged along the rear faces of the tiles of the assembly.

The self-rolling concrete is reinforced with fibers, preferably metal fibers. - A mesh, preferably a wire mesh or non-organic fibers, is embedded in said self-rolling concrete.

- The fasteners are aligned along substantially vertical lines and / or horizontal regularly spaced apart from said distance A.

- At least a portion of the tiles are mounted in vertical or horizontal staggered, preferably vertically and horizontally staggered.

The coating according to the invention is particularly intended to protect a wall of a gasifier reactor.

The gasification of coal is a known process for about fifty years which is currently experiencing a strong development. It allows the production of a part of synthesis gas (CO, H ₂ ), sources of clean energy, and secondly of basic compounds for the chemical industry from very diverse hydrocarbon materials, by example of coal, petroleum coke, or heavy oils to recycle. This process also makes it possible to eliminate undesirable components, for example NOx, sulfur or mercury, before any discharge into the atmosphere.

The principle of gasification consists of a controlled partial combustion, under steam and / or oxygen, at a temperature of between about 1150 and 1600 ^° C. and under pressure.

There are different types of gasifiers, fixed bed, fluidized or driven. These gasifiers differ in the manner in which the reactants are introduced, the manner in which the fuel-fuel mixture is carried out, the temperature and pressure conditions, and the ash or slag removal process, the liquid residue resulting from the reaction.

A pressurized, fluidized bed dry gasifier 5 of the "Lurgi fixed bed dry ash gasifier" type is particularly known. As shown in FIG. 1, coal C in pieces penetrates through the top 10 of the gasifier and is introduced via a feed device 12 into a reactor 14. Water vapor H ₂ O and oxygen O ₂ penetrate through the lower part 16 of the gasifier 5 and react with the carbon C as they rise in the reactor 14. In the lower part 16 of the reactor 14, the temperature is about 1600 ^° C. In the upper part 18 of the reactor 14, the temperature is about 450 to 900 ^° C. The ash D is extracted at the base of the gasifier 5. The synthesized gas G escapes through an outlet 20. The dry coal gasification reactor 14 comprises a water cooling jacket 22 or "water box", or in English "water-jacket", steel . The jacket 22 comprises an outer wall 24 and an inner wall 26, seat of a strong corrosion, delimiting, at least in part, the internal volume of the reactor 14. Such a reactor has a limited lifetime due to thermal cycling and and / or corrosion and / or abrasion of dry ashes and / or hot spots where the temperature is typically about 1400 ^° C.

The tiles according to the invention are particularly suitable for protecting the wall of a gasifier reactor, this wall not being made of tubes. Preferably, the fixing of the refractory tiles results from their attachment to fixing members fixed to said wall. The protective coating obtained is advantageously compact, reliable and easy to implement, as will appear in more detail in the following description.

Finally, the invention relates to a method for determining the overall thermal conductivity of a coating of a wall of a reactor, the coating comprising an assembly of refractory tiles, remarkable in that a concrete of predetermined conductivity is cast between the assembly of tiles and said wall.

Other characteristics and advantages of the invention will appear on reading the description which follows and on examining the drawings in which:

Figure 1 shows schematically in section a gasifier Lurgi type;

Figures 2 and 3 show photographs of the rear and front sides, respectively, of two tiles according to the invention; The photographs are arranged so that the tiles appear as they would be in a reactor assembly, the top of the sheet representing the top of the assembly.

Figures 4 to 8 show schematic views of the rear faces of different tiles according to the invention; Figure 9 shows a schematic view of the rear faces of an assembly of four tiles according to the invention;

Figure 10 shows a fastener that can be used to secure the tiles of an assembly according to the invention; - Figure 11 shows a front view of a tile assembly according to the prior art. This assembly being cylindrical, it is represented in a developed form;

FIG. 12 represents a front view of an assembly of tiles of the same format according to the invention. This assembly being cylindrical, it is represented in a developed form;

Figure 13 shows a front view of an assembly of tiles of different sizes according to the invention. This assembly being cylindrical, it is represented in a developed form.

In the various figures, identical or similar references are used to designate parts or parts of the same or similar parts.

FIG. 1 having been described in the preamble, reference is now made to FIG.

The following description is made in the context of a coating of the gasifier described in the preamble. The invention is however not limited to this application.

A tile 30 is generally rectangular cylindrical in shape, having in fact a slight curvature to follow the shape of the inner wall of the jacket 22 of the reactor 14.

Preferably, the tile 30 is of thermally insulating material. Preferably, this material comprises at least 60%, preferably at least 90%, more preferably at least 99% by weight, of non-siliceous oxides.

Preferably, these non-siliceous oxides are chosen from alumina, zirconia, Cr ₂ O ₃ chromium oxide or mixtures thereof. Any other refractory material capable of resisting the corrosion of ashes possibly melted, abrasion of dry ashes and hot spots could however be suitable.

Preferably, the material of the tile according to the invention does not comprise silicon carbide (SiC). More preferably, it comprises less than 1%, preferably less than 0.5% by weight of silica (SiO ₂ ). Silicon carbide and silica are indeed unfavorable to corrosion resistance. In addition, the silica may be unstable and evaporate in SiO ₁ or SiH _{4 form} .

The tile 30 has front 32 and rear 34 and top 36, lower 38, right 40 and left 42. The rear face 34, or "cold face" of the floating tile 30 has first 44 and second 46 notches extending substantially parallel to the side edges 40 and 42, along the right 40 and left 42 respectively. The notches 44 and 46 open through first 48 and second 50 lower openings, respectively, on the lower edge 38 and by first 52 and second 54 rear openings, respectively, on the rear face 34.

The faces 32, or "hot face" and 34, or "cold face" of the floating tile 30 are substantially curved to follow the curvature of the reactor.

As shown in FIGS. 2 and 3, upper and lower edges 36 and 38 have upper and lower lips 54 enabling the lower edge 38 of a tile to be covered by the top edge 36 of another tile disposed immediately beyond above her. Similarly, the right 40 and left 42 slices have lips allowing recovery of the right edge 40 of a tile by the left edge 42 of another adjacent tile. The cover lips avoid revealing the cooling jacket during the movement of the tiles relative to each other. Advantageously, the protection of the liner 22 is improved.

As will be seen in more detail in the following description, the tile 30 is provided to be attached to a fastener having the general shape of a nail having a rod and a head. After hooking, the bottom of the notch rests by gravity on the head of the fastener which thus supports the weight of the tile.

A rear opening of a notch 45 has, seen from the rear of the tile, as shown in FIG. 2, a narrow upper portion 45s extending to a bottom 55 of the notch 45. The notch 45 is shaped to allow the sliding of a rod of a T-fastener in the upper part 45s, but not allow an axial passage of the head of this fastener. The cross section of the upper portion 45s preferably has an omega shape for this purpose. After hooking of the tile, this type of profile advantageously prevents the escape of the head through the rear opening of the tile, and thus prevents any tilting and inadvertent detachment of the tile.

A rear opening also preferably has a wide lower portion 45i for introducing a head of a fastener. Advantageously, this head can thus be introduced into the notch 45 through a lower opening or through a lower portion of a rear opening.

The rear face 34 of the tile 30 still has spacers or

"Spacers" 56 which are preferably shaped to maintain a spacing of between 2 and 5 mm between the rear face of the tile and the inner wall 26 of the cooling jacket. Advantageously, the spacing of the tiles of the wall governs the heat exchange.

The presence of several slots per tile, preferably two, advantageously ensures the maintenance in position of the tile in case of failure of one of the attachment points.

As seen in Figure 3, an expansion space 60 is provided between two adjacent tiles. This expansion space 60, however, allows direct access to the rear face of the tiles. The lower openings on the lower slices of the tiles are indeed not covered by the covering lips of the tiles and thus leave a direct passage 62 from the inside of the reactor 14 to the inner wall 26 of the cooling jacket, available for the gas or other aggressive agent.

FIGS. 4 to 8 show tile shapes having two notches aligned horizontally, and which advantageously have the common characteristic of being shaped and / or assembled so as to close all direct access to the rear face of the tiles by means of the notches. It is thus understood that, even before any interposition of an expansion joint between two tiles, there is no passage passing through the tile assembly in a substantially rectilinear manner, in particular extending perpendicularly to the front faces of the tiles, and thus putting the back of the tiles in communication with the internal volume of the reactor.

As will be seen below, it is preferable to have a self-rolling concrete behind the tiles, in particular to glue them to the cooling jacket 22. Hinder the communication between the rear and front faces of the tiles. Another advantage of tiles is that, during the installation of the protective coating, the concrete does not flow into the expansion spaces 60. In this situation, the tiles could no longer expand during the operation of the gasifier without the expansion does not generate high and undesirable thermomechanical stresses.

The arrangement of the upper lip 53 in the extension of the front face of a tile makes it possible to form an enlarged opening to access behind the tile. Advantageously, pouring concrete behind this tile is facilitated.

In a first variant (FIGS. 4 and 5), the notches 45 do not open on the lower edge of the tile 30, that is to say that the notches 45 are in the form of holes opening only on the back side of the tile. A slot not opening on the lower edge of the tile can be formed by assembling a plug 70, for example by gluing, so as to plug its lower opening on the lower edge, as shown in Figure 5. Advantageously, it is thus It is possible to use tiles such as those shown in FIG. 2. A notch that does not open on the lower edge may also have come into shape with the tile during its manufacture.

The lower portion 45i of a notch that does not open on the lower edge of the tile must necessarily be shaped to allow the introduction of a head of a fastener, the latter can not be introduced by the lower edge.

In a second variant (FIGS. 6 and 7), the tile comprises tabs 72 that can fit into corresponding notches of another identical tile. Preferably, the tile has as many said tabs as it has notches, so that when an assembly of an upper tile immediately above a lower tile, all the lower openings of the notches of the tile upper are closed by the tabs of the lower tile. This characteristic can be obtained by assembling the tongues on an existing tile, for example by gluing, (FIG. 7) or by conformation of tongues during the manufacture of the tile (FIG. 6).

In a third variant (FIG. 8), a plug 74, preferably having the same composition as the tiles, is inserted between the tiles after their assembly, so as to block any direct access to the rear face of the tiles through the notches, while preserving an expansion joint. Preferably, the plug 74 has the same refractory composition as the tiles.

Preferably, all the notches of all the tiles of the assembly are closed in at least one of the solutions illustrated in FIGS. 4 to 8.

As shown in FIG. 9, the distance A between the axes E1 and E2 of the notches 44 and 46 is smaller than the sum of the distances ai and α ₂ separating these axes E1 and E2 from the right 40 and left 42 slices, respectively. In other words :

More generally, if the tile had "n" notches regularly spaced a distance A _n , according to the invention,

Preferably eι is between 2 and 10 millimeters.

The slices of the tile 30 are not flat, we measure ai and α ₂ on the rear face of the tile. It is the same for the length L of the tile and its height H.

FIG. 10 shows a fastener 80 comprising a threaded rod 82 whose first end 84 is welded to the inner wall 26 of the jacket 22. A head, or "washer" 86, is screwed onto the second end 88 of the rod 82.

A clearance is provided between the head 86 and the notch 45 so that the fasteners 80 do not hinder the expansion of the tile 30.

According to the prior art, the fasteners 80 of the type shown in FIG. 10 are welded to the inner wall 26 of the jacket 22, substantially perpendicular to the wall 26 (FIG. 10). They are aligned along substantially vertical lines Lv and horizontal Lh. The spacing F between two adjacent vertical lines Lv is not constant and depends on the tiles used, as shown in FIG.

In the application to a gasifier reactor, the installation of an irregular grid of fasteners 80 as shown in FIG. 11 has several disadvantages. It can first lead to errors when positioning the fasteners. It is necessary in fact three templates to ensure the correct vertical spacing of the fasteners, the correct horizontal spacing of fasteners 8O ₁ and 8O ₂ intended to receive two notches of the same tile and the correct horizontal spacing of fasteners 8O ₃ and 8O ₄ for receiving two notches of two different adjacent tiles. In addition, all connections between two "columns" of tiles must necessarily be on the same vertical. In particular, tiles can not be staggered. This results in heterogeneity and fragility of the coating.

Unlike the arrangement of the fasteners shown in Figure 11, the fasteners 80 are preferably aligned along substantially vertical lines Lv regularly spaced a distance A, that is to say, the distance A separating the axes E1 and E2 from the notches of a tile. The fasteners are also aligned along substantially horizontal lines regularly spaced a distance B. Preferably, the distance B is greater than the height H of a tile, that is to say that 0 <e _h = BH.

A "spread" of two tiles does not mean that these two tiles do not touch, but that in the direction considered, a relative movement of one tile relative to the other is possible. Thus the spacing eι of two tiles according to the width means that a tile can expand laterally by a distance el and before abutting with the tile next to it. The spacing eh according to the height of two tiles means that a tile can expand upwards or downwards by a distance e _h before coming into abutment with the tile on top or below it. It is preferable that the distance B be equal to the distance A. The same template can thus be used to ensure correct vertical and horizontal spacings.

As eι + (α-i + α ₂ ) = A, the same template can be used to check the spacing of two fasteners 8O ₁ , 8O ₂ side by side and intended to receive the same tile and to check the spacing two fasteners 8O ₃ , 8O ₄ side by side and intended to receive different tiles. A single template can therefore advantageously be used for the positioning of all fasteners.

In addition, the apparatus of the tiles is not fixed by the establishment of fasteners, a row of tiles may for example be offset laterally by a length corresponding to the spacing between two notches of a tile if necessary. Unlike the prior art, a half tile can be easily incorporated even after welding of the fasteners. It is thus possible to mount the tiles staggered to enhance the protection afforded by the refractory lining, to easily incorporate a passage for a thermocouple embedded in a cushioning concrete 90 or to account for a rough surface, having for example a opening or hole 92, with a lot of flexibility.

A comparison of the apparatus of Figures 11 and 12 shows that the apparatus of Figure 12 requires three blanks of tiles, while that of Figure 11 requires nine.

Before hanging the tiles, a grid, preferably a wire mesh or non-organic fibers, is preferably attached to the fasteners.

The tiles are then attached to the fasteners 80 by insertion of the latter into the notches 45. Preferably the tiles are of the type shown in FIGS. 4 to 8. In the case of the tiles of FIG. 8, the plugs

74 can be set up as tiles are assembled or after all the tiles have been hung.

The washers 86 are dimensioned so as to allow insertion of the fasteners 80 to the bottom 55 of the notches while preventing clearance by the upper portion 45s of the rear opening of the notches, partially closed in fact its omega profile Ω. The fasteners 80 thus serve to support the weight of the tiles

(console function), but also to prevent tilting of the tiles by keeping them substantially pressed along the wall 26.

The order in which the tiles are hung depends on the profiles of their slices. It is determined to ensure overlap between adjacent tiles provided by the manufacturer of the tiles.

According to the invention, a self-rolling concrete is preferably cast in the space between the tiles and the inner wall of the cooling jacket.

This space is guaranteed thanks to the presence of the spacers 56, resting on the wall

26. Advantageously, the spacers 56 avoid direct contact of the rear face of the tile and the wall, and thus improves the thermal protection of the latter.

Since the spacers 56 extend only over only a portion of the height H of said tile, they do not hinder the flow of concrete behind the tile. Advantageously, the concrete can thus be distributed uniformly behind the tiles.

Preferably the self-flow concrete is based U ¹ Al ₂ O ₃ or Al ₂ O ₃ -Cr ₂ O ₃ or similar in nature to tiles. The self-rolling concrete advantageously makes it possible to regulate the overall conductivity of the coating, by its nature and its thickness. Its composition can be modified accordingly. For example, a self-hardening concrete based on SiC or enriched in metallic or ceramic fibers, for example of the Dramix® or Unifrax type, can advantageously be used if it is necessary to increase the thermal conductivity of the coating, that is to say ie to increase the heat transfer to the cooling jacket, in particular to manufacture water vapor necessary for the gasification system.

The self-rolling concrete also makes it possible to protect the inner wall 26 of the cooling jacket in the event that a tile is unhooked. It also helps the tiles to withstand the pressure of several tens of bars prevailing inside the reactor in operation.

Finally, it blocks any direct access to the rear faces of the tiles, and therefore to the metal wall 26 of the cooling jacket.

In case of breakage of a tile by tearing, the self-collapsible concrete is sometimes torn off with the tile. Indeed, it may be mechanically linked to it, in particular by filling the notches receiving the washers 86 of the fasteners.

The wire mesh or inorganic fiber, disposed between the inner wall 26 of the cooling jacket and the rear face of the tiles, that is to say in the area where the self-cast concrete is then cast, advantageously improves the cohesion of the concrete layer and retains it locally in case of tearing or detachment of one or more tiles. Alternatively or in addition to the mesh, the self-rolling concrete may advantageously be reinforced with fibers, preferably metal fibers, mixed with its other constituents during its preparation.

After pouring the concrete, a flexible mortar is placed in the expansion spaces separating the tiles, so as to form an expansion joint. The expansion joint thus has a width e _h on its horizontal portions and a width β | on vertical portions. Flexible mortars conventionally comprise ceramic fibers. As examples, mention may be made of Fiberfrax® produced by Unifrax.

When the gasifier 5 is in use, the heat variations within the reactor 14 cause expansion of the tiles. The spacing of the tiles relative to each other, however, allows them to expand without generating high mechanical stresses.

The expansion joint compresses under the effect of expansion and then resumes its original shape when the tiles contract again. At any time during a thermal cycle, the inner wall of the reactor cooling jacket thus remains effectively protected.

If the expansion joint is damaged, the shape of the tiles or the presence of plugs 74 (FIGS. 4 to 8) advantageously avoids any direct access of the materials contained in the reactor to the concrete and to the inner wall of the cooling jacket.

Finally, if a tile is unhooked, the self-cast concrete still maintains a protective barrier of the liner 22. This barrier is all the more certain that a grid has been provided between the wall 26 of this liner and the tiles and that the concrete is reinforced with fibers. All the tiles of the assemblies shown in FIGS. 11 and 12 are identical. As shown in Figure 13, a mixture of different tiles can however be advantageous, especially to allow the assembly of tiles to surround an obstacle 92 as closely as possible, and thus to limit the areas of the coating made of cushioning concrete 90 As now clearly apparent, in the preferred embodiment, the invention provides a thermally insulating refractory lining that is resistant to corrosive gases, is compact, easy to disassemble, and has increased reliability. This coating is particularly suitable for protecting the jacket of a reactor from a gasifier. Of course, the present invention is not limited to the embodiments described and shown, provided by way of illustrative and non-limiting examples.

In particular, it is possible to have several notches superimposed on the same tile in order to be able to vertically offset two tiles side by side and thus removing the continuous alignment of the horizontal joints. The tiles are preferably mounted in vertical quincunx, all the tiles of a column being offset from the tiles of the two columns adjacent thereto.

In addition, the application of the tiles according to the invention is not limited to the coating of water boxes gasifiers.

In addition, the tabs 72, the plugs 74, the closing of notches on the lower edge of the tiles, the grid, the self-collapsible concrete, the arrangement of the fasteners shown in Figure 11 are optional. The number of tabs, plugs 74, notches is not limiting. Finally, the notches, which form attachment points, are not the only possible fixing points. Any point of the tile according to the invention serving as a fulcrum for fasteners may be considered as a point of attachment.

Claims

1. Refractory tile, in particular for protecting an inner wall (26) of a gasifier reactor, said tile having an alignment of at least two fixing points, any two adjacent fixing points of said alignment being spaced apart by a distance constant A, first (44) and last (46) fixing points of said alignment being spaced, in the direction of said alignment, by distances ai and α ₂ from first (40) and second (42) edges of said tile extending in proximity to the first (44) and last (46) attachment points, respectively, characterized in that A - (αi + α ₂ ) is between 2 and 10 millimeters.

2. refractory tile according to claim 1, characterized in that, in a service position of the tile, said alignment is vertical or horizontal.

3. refractory tile according to one of claims 1 and 2, characterized in that said fixing points are notches.

4. refractory tile according to claim 3, characterized in that it comprises at least one notch opening exclusively on a rear face of said tile.

5. refractory tile according to one of the preceding claims, characterized in that it comprises at least one notch (44; 46) opening through a lower opening (48; 50) on a lower edge (38) of said tile, and at least one tongue (72) adapted to be introduced, at least in part, by a lower opening (48; 50) of a notch (44; 46) of another identical tile.

6. refractory tile according to one of the preceding claims, characterized in that it has, on a rear face (34), at least one spacer (56) extending over only a portion of the height H of said tile.

7. refractory tile according to one of the preceding claims, characterized in that it comprises upper slices (36) and lower (38) having upper (53) and lower (54) lips extending in extension of front faces (32) and rear (34) of said tile, respectively.

8. refractory tile according to one of the preceding claims, characterized in that it is a material having at least 60%, in percentages by weight, of non-siliceous oxides.

9. refractory tile according to one of the preceding claims, characterized in that it is a material having less than 1% by weight of silica (SiO ₂ ).

10. Refractory coating, in particular for protecting the inner wall (26) of a gasifier reactor, said coating comprising an assembly of refractory tiles (30) secured to fasteners (80) fixed to a wall (26), characterized in that said cladding comprises at least one tile (30) according to any one of the preceding claims.

11. The coating of claim 10, characterized in that a first tile dressing is spaced apart from at least a second tile disposed to its right or left by a distance β | equal to A - (0 ^ + Oc ₂ ) and / or is spaced apart by at least one third tile disposed above or below it by a distance e _h equal to A '- (αi' + α ₂ '), where A and A' denote the spacing of any two adjacent attachment points of a horizontal alignment and a vertical alignment of said first tile, respectively, Ot ₁ 'and α ₂ ' denote the distance between first and last attachment points of said vertical alignment of upper and lower edges of said first tile, respectively, and Oc ₁ and α ₂ denote the distance between first and last fixing points of said horizontal alignment of right and left edges of said first tile , respectively.

12.Coating according to any one of claims 10 and 11, characterized in that a refractory concrete autocoulable is disposed along the rear faces of the tiles of the assembly.

13. Coating according to any one of claims 10 to 12, characterized in that at least a portion of the tiles are mounted in vertical and / or horizontal staggered.