EP2857750B1 - Shaped refractory brick - Google Patents

Description

The present invention relates to the field of refractory bricks, also called tiles or shaped parts, for combustion chamber wall.

Combustion chamber means indistinctly an oven or boiler. Concisely, we will describe here only the example of bricks for boiler.

There are generally two types of ovens: static ovens and rotary ovens.

In a rotary kiln combustion chamber, the bricks are only subjected to reversible thermal deformation. An example of bricks for rotary kilns is known from the document US2010 / 0180806 , which proposes a design of part and joints between the bricks for cylindrical furnaces allowing the maintenance of the bricks and the waterproofness of the wall taking into account this reversible thermal expansion. Another example of bricks for rotary kilns is known from the document EP 0 103 365 A1 , which offers a refractory brick tolerant of thermal expansion. The document EP 2,302,315 proposes a protection plate of pipes, called anticorrosion body. The document EP 0 281 863 proposes, for its part, a screen protection device for boilers to prevent the progressive destruction by oxidation of poorly cooled metal parts.

On the contrary, here, the aim here is the bricks for static combustion chamber, in which the bricks are subjected to both a reversible thermal deformation at the temperatures of use, and to a non-reversible chemical deformation.

Schematically, a boiler comprises a combustion chamber. At least one wall of the combustion chamber is equipped with an assembly of at least one tube. In operation, the combustion is carried out in the combustion chamber and a fluid flows inside the set of tubes. The heat of combustion is transmitted through the tubes to the coolant circulating there. The fluid makes it possible to value the heat energy transferred typically in the form of heat and / or electricity.

However, combustion generally generates corrosive fumes that degrade the tubes, the corrosion being a function of the fuel used, the flue gas temperature and the temperature of the tubes.

It is therefore expected to protect the tubes from corrosion by a set of refractory bricks which, in addition, transmit the heat of combustion to the tubes.

Bricks are therefore on the one hand thermal conductors that transfer heat from a combustion made in a boiler combustion chamber to a set of tubes in which a fluid transits; and secondly they exert a protective function of said tubes against corrosion generated by combustion fumes.

In a combustion chamber, the bricks are affixed next to each other and fixed to the boiler tube wall by means of metal fastening systems in which the bricks equipped with blind housing are inserted. There are different models of fastening systems associated with blind housing of corresponding design. A seal is affixed around each brick to connect two adjacent bricks together, so as to form a sealed wall impervious to the passage of combustion fumes to the boiler tubes.

In operation, the bricks are subjected to high temperatures (typically 1200 ° C. to 950 ° C. in flue gas temperature) and to aggressive atmospheres, for example based on alkalis, sulfur or chlorine, typically during heating. incineration of certain wastes or biomass.

Under these conditions, the chemical deformation and the thermal deformation have the effect that the bricks deform in the form of banana, that is to say that the deformation is more important in hot face than in cold face. As a result, it sometimes happens that some bricks unhook or break, which exposes the tubes to corrosive fumes and requires maintenance interventions of the boiler that penalize the operation.

The object of the present invention is to remedy these drawbacks by proposing, according to a first of its objects, a refractory brick comprising the characteristics mentioned in claim 1.

Thanks to these characteristics, in a first embodiment, the brick can be part of a solid having as bases two equal and parallel polygons, the sides of which are united by polygons, in particular of which at least two opposite sides are inscribed. each in an isosceles trapezoid. In a second embodiment, the brick can be part of a prism, that is to say a solid based on two equal and parallel polygons, whose sides are united by parallelograms.

Advantageously, the bricks according to the invention have at least one plane of symmetry passing through the center thereof. Advantageously, a cross section (perpendicular to the plane of the hot face and the plane of the cold face) of the brick according to the invention is in a trapezium, in particular isosceles.

• la valeur de l'écart entre la largeur (W_h) de la face chaude et la largeur (W_c) de la face froide est supérieure ou égale à la valeur de la déformation de la face chaude (HF) dans le sens de ladite largeur dans les conditions d'utilisation de ladite brique, et
• la valeur de l'écart entre la longueur (L_h) de la face chaude et la longueur (L_c) de la face froide est supérieure ou égale à la valeur de la déformation de la face chaude (HF) dans le sens de ladite longueur dans les conditions d'utilisation de ladite brique.

Preferably:

• the value of the difference between the width (W_h) of the hot face and the width (W_c) of the cold face is greater than or equal to the value of the deformation of the hot face (HF) in the sense of said width in the conditions of use of said brick, and
• the value of the difference between the length (L_h) of the hot face and the length (L_c) of the cold face is greater than or equal to the value of the deformation of the hot face (HF) in the direction of said length in the conditions of use of said brick.

Preferably, the brick comprises a material based on silicon carbide.

In particular, the bricks are of oxide-bonded silicon carbide.

It can be provided that the bricks are nitride-bonded silicon carbide or oxy-nitride.

It can be provided that the cold face (CF) has at least one recess (102, 202) configured to conform to the shape of said at least one tube.

It can be expected that the depth (D_p) of the brick at its periphery is less than or equal to the depth (D_h) of the brick in its heart.

It can be expected that the hot face (HF) is substantially flat.

It can be expected that at least a portion of the cold face (CF) fits in a plane.

Preferably, the plane in which at least part of the cold face (CF) is inscribed is parallel to the hot face (HF).

According to the invention, at least two opposite lateral faces have a bevel with an angle θ.

According to another of its objects, the invention relates to a furnace or a static combustion chamber capable of being subjected to corrosive atmospheres which may comprise a plurality of refractory bricks (100, 200) according to the invention. Preferably, the furnace or combustion chamber comprises a set of identical refractory bricks.

The present invention makes it possible to produce a form of brick that makes it possible to anticipate irreversible deformations of chemical origin of the latter during its use, by providing inclinations and withdrawals of material at the places known to undergo the strongest deformations. and which, in their absence, would generate by these deformations additional mechanical stresses on the adjacent bricks, and which could further refer to the fastening system.

• La figure 1 illustre une coupe transversale d'un premier mode de réalisation de la brique, selon l'axe B-B de la figure 3, incluant le logement borgne.
• La figure 2 illustre une coupe transversale du premier mode de réalisation de la brique, excluant le logement borgne.
• La figure 3 illustre une coupe longitudinale du premier mode de réalisation de la brique, selon l'axe A-A de la figure 2.
• La figure 4 illustre une coupe transversale d'un deuxième mode de réalisation de la brique, selon l'axe B-B de la figure 6, incluant le logement borgne.
• La figure 5 illustre une coupe transversale du deuxième mode de réalisation de la brique, excluant le logement borgne.
• La figure 6 illustre une coupe longitudinale du premier mode de réalisation de la brique, selon l'axe A-A de la figure 5.
• La figure 7 illustre une vue de dessus, par la face chaude, du premier mode de réalisation de la brique dans lequel la face chaude est centrée par rapport à la face froide.
• La figure 8 illustre une vue de dessus, par la face chaude, du deuxième mode de réalisation de la brique.
• La figure 9 illustre en coupe longitudinale, deux briques selon le premier mode de réalisation accrochées sur un dispositif individuel de fixation respectif.
• La figure 10 illustre l'évolution des différents types de déformation d'une brique en fonction du temps d'exposition de la brique à une atmosphère corrosive, pour une pluralité de températures.

Other characteristics and advantages of the present invention will emerge more clearly on reading the following description given by way of illustrative and nonlimiting example and with reference to the appended figures in which:

• The figure 1 illustrates a cross section of a first embodiment of the brick, along the axis BB of the figure 3 , including blind housing.
• The figure 2 illustrates a cross-section of the first embodiment of the brick, excluding the blind housing.
• The figure 3 illustrates a longitudinal section of the first embodiment of the brick, along the axis AA of the figure 2 .
• The figure 4 illustrates a cross-section of a second embodiment of the brick, along the axis BB of the figure 6 , including blind housing.
• The figure 5 illustrates a cross-section of the second embodiment of the brick, excluding the blind housing.
• The figure 6 illustrates a longitudinal section of the first embodiment of the brick, along the axis AA of the figure 5 .
• The figure 7 illustrates a view from above, by the hot face, of the first embodiment of the brick in which the hot face is centered with respect to the cold face.
• The figure 8 illustrates a top view, by the hot face, of the second embodiment of the brick.
• The figure 9 illustrates in longitudinal section, two bricks according to the first embodiment hooked on a respective individual fastening device.
• The figure 10 illustrates the evolution of the different types of deformation of a brick as a function of the time of exposure of the brick to a corrosive atmosphere, for a plurality of temperatures.

The refractory bricks according to the invention find particular utility in a furnace or a static combustion chamber, typically a boiler. They are therefore intended for this use, indistinctly suitable for this use or are configured for this use.

A first embodiment of firebrick is illustrated in figure 1 to 3 described below.

A second embodiment of firebrick is illustrated in figure 4 to 6 described below.

In each of these two examples, the brick is intended to cover a combustion chamber wall.

The combustion chamber comprises an assembly of at least one tube for the flow of a coolant. The combustion chamber also includes a fastening system comprising a set of individual fasteners, each individual device being configured to hang an individual brick. An individual brick is intended to be near or in contact with at least one tube.

The brick has a hot face HF and a cold face CF. The hot face HF is intended to be exposed to combustion fumes from the combustion chamber. The cold face CF is intended to be near or in contact with at least one tube; it is also equipped with a blind housing for fixing the brick to an individual fixing device.

Preferably, the hot face is flat or has a large radius of curvature, which simplifies their manufacture, the cleaning of the combustion chamber and limits the risk of corrosion by channeling fumes better.

The brick fits for example in a polyhedron. As the bricks are intended to be affixed to each other, they advantageously have, at least in cross section, a shape that fits in a rectangle.

The hot face HF has a width W_h and a length L_h.

The cold face CF is opposite to the hot face and has a width W_c and a length L_c.

Faced with the problem of stall or breakage of bricks, studies have been conducted by the applicant, which results that these breaks or falls are due to irreversible deformations of the bricks under the combined effect of temperature and chemical species present in combustion fumes. These deformations cause strong mechanical stresses in the fixing of the bricks and between the bricks themselves which tend to repel each other, despite the joints between them, and thus tend to move away from the wall of the combustion chamber against which they are placed.

In particular, the incineration of waste or the combustion of biomass produces chemical species that penetrate the bricks and generates chemical reactions within them which can cause them to swell by thermal expansion coupled with chemical reactions.

In the case of silicon carbide bricks, in particular with an oxide bond, these are porous. The deformation phenomenon takes place essentially in the hot face, at a flue gas temperature above 650 ° C.

In cold face, there is no deformation or deformation is negligible compared to that of the hot face. This advantageously allows that the cold face may have at least one recess configured to conform to the shape of at least one tube, this recess is not deformed.

In new condition, the bricks initially have a shape in a rectangular parallelepiped. After deformation, it has been observed that they have a shape curved (oval) in hot face in the direction of the length and width of the brick.

However, if the thermal expansion of the bricks is reversible, however, the chemical deformation they undergo is irreversible and generates a mechanical stress in the cold face, to the individual device for fixing each of them.

Also, to respond to the thermal, chemical and mechanical coupling that certain bricks undergo, and to fight against the phenomenon of deformation, one can seek to increase the size of the joints between the bricks. However, this solution penalizes the heat exchange between the flue gases and the coolant of the tubes and greatly increases the risk of corrosion of the tubes. One can also seek to modify the physico-chemistry of combustion, which is not always possible in an industrial environment; or seek to replace silicon carbide bricks with other materials that are less subject to deformation, but at the risk of being more expensive.

The present invention aims to solve this problem of bricks capable of deforming by cleverly modifying the shape of existing bricks, so as to anticipate the possible deformation they could undergo.

Indeed, during the temperature rise of the furnace, the materials of the bricks undergo a thermal expansion which depends on the nature of the material and which is directly proportional to the local temperature.

For a brick composed of isotropic materials, the variation in the length of the hot face (the cold face undergoing less thermal expansion, it deforms less than the hot face, hence a "banana-type" deformation between an initial temperature T0 and a final temperature T is expressed as follows: $$\mathrm{.DELTA.L}\_\mathrm{Thermal}=\mathrm{\alpha }\times {\mathrm{The}}_0\times \mathrm{DT}$$

• ΔL_Thermique : la variation de longueur en m ;
• α un coefficient de dilatation linéaire en K^-1 ;
• L0 la longueur initiale en m de la brique à température initiale T0; et
• ΔT = T-T0 la variation de température en degrés K ou C.

With

• ΔL_Thermic: the variation of length in m;
• α linear coefficient of expansion in K ^-1 ;
• L0 the initial length in m of the brick at initial temperature T0; and
• ΔT = T-T0 the temperature variation in degrees K or C.

The bricks being subjected to a temperature gradient between the face exposed to the fumes and the face in contact with the wall of a boiler tube, a thermal expansion gradient is created within the brick, and this is then subject to a reversible deformation.

In the presence of a corrosive environment of slag or gaseous type, the corrosive species penetrate or diffuse within the brick via the porosities thereof.

The temperature gradient then acts as a driving force for the penetration of these chemical species, which then fill the porosities and react with the materials of the brick, thus forming new metallurgical phases (by allotropic transformation) whose molar volume can be more important than that of the initial phases.

In addition, the chemical reactivity is thermally activated. Consequently, at the operating temperatures of a furnace, a volume expansion gradient is created within the brick and results in irreversible deformation of chemical origin.

The chemical deformation (ΔL_chemical) is then a function of the progress of chemical reactions of oxidation of the material of the brick or the formation of new expansive phases.

The overall deformation of the brick is then expressed as follows $$\mathrm{.DELTA.L}\_\mathrm{overall}=\mathrm{.DELTA.L}\_\mathrm{elastic}+\mathrm{.DELTA.L}\_\mathrm{thermal}+\mathrm{.DELTA.L}\_\mathrm{chemical}$$

• Δ_L_élastique, la déformation réversible d'une brique soumise des forces extérieures,
• ΔL_thermique, la déformation réversible d'une brique sous l'effet de la température évoquée précédemment, et
• ΔL_chimique, la déformation irréversible d'une brique sous l'effet de variation de volume associée à sa dégradation chimique.

With:

• Δ_L_elastic, the reversible deformation of a brick subjected to external forces,
• ΔL_thermique, the reversible deformation of a brick under the effect of the temperature mentioned above, and
• ΔL_chemical, the irreversible deformation of a brick under the effect of volume variation associated with its chemical degradation.

The experiment shows that in the presence of corrosive atmospheres, the contribution of the chemical deformation (of the order of 10%) is much more important than the reversible contributions of the elastic or thermal deformation (of the order of the%) .

As illustrated figure 10 , depending on the time of exposure of a brick to a corrosive atmosphere, it undergoes first a reversible thermal deformation and then an irreversible chemical deformation. The influence of thermal deformation remains substantially constant over time while the influence of chemical deformation increases over time, up to a maximum not shown.

As a result, on the one hand, the elastic Δ_L_elastic deformation can be neglected, and on the other hand, the large dimensional variations in the hot face generate high stresses within the brick and are partly accommodated by a deformation in front of the brick. cold.

This deformation in cold face then makes appear new mechanical stresses between the brick and the wall of the boiler tube and between the fastening system and the bricks.

In this context, it is expected that the width W_h of the hot face HF is less than the width W_c of the cold face CF.

It can be provided in combination that the length L_h of the hot face is less than the length L_c of the cold face.

As the deformation is essentially in the hot face and in the plane thereof, the dimensions of the hot face lower than those of the cold face, in case of expansion of the hot face, to limit the risk of stall.

Preferably, it is expected that the value of the difference between the width W_h of the hot face and the width W_c of the cold face is greater than or equal to the value of the deformation of the hot face in the direction of said width in the conditions of use of said brick.

Similarly, it is preferably provided that the value of the difference between the length L_h of the hot face and the length L_c of the cold face is greater than or equal to the value of the deformation of the hot face in the direction of said length in the conditions of use of said brick.

Thus, the width W_h_f of the hot face HF after deformation is at most equal to the width W_c of the cold face CF; and the length L_h_f of the hot face after deformation is at most equal to the length L_c of the cold face.

With such initial dimensions, if the brick undergoes maximum deformation under conditions of use, the final width after deformation W_h_f of the hot face becomes at worst equal to the width W_c of the cold face; and the final length after deformation L_h_f of the hot face becomes at worst equal to the length L_c of the cold face. Under these conditions, the brick after deformation fits in a rectangular parallelepiped and the deformation of a brick does not exert stress on an adjacent brick, but only on the joint which connects them.

In figure 9 is illustrated a longitudinal section of two adjacent bricks according to a first embodiment described later, identical to each other, under conditions of normal use, before possible deformation.

A first brick 100a is attached to a first individual fastener 1000a, and a second brick 100b is attached to a second individual fastener 1000b.

In this case, the initial distance D_CFi separating the two cold faces CF is smaller than the initial distance D_HFi separating the two hot faces HF.

If these bricks undergo a deformation, the free space E initially reserved on the cold face CF between the brick and the tubular wall TUB makes it possible to accommodate the deformation of the tile in the hot face HF by limiting the support on the wall and therefore the constraints on the fastening system.

Once the maximum deformation of the brick reached, this free space E can disappear and the cold face can then be in contact but without constraint with the wall. In addition, the final distance D_HFf (not shown) separating the two hot faces HF, is comparable in size to the initial distance D_CFi separating the two cold faces CF, since it is almost invariable.

With respect to a rectangular parallelepiped illustrated in dotted lines on the figure 1 one way of illustrating the invention consists, for example, in considering that at least two opposite lateral faces have a bevel with an angle θ.

Thus, the lateral faces are inclined at an angle θ ranging for example from 0 to 20 °, which increases the initial space between two hot faces of two adjacent bricks and delay or avoid the brick-to-brick contacts during deformation.

As illustrated figure 9 , the hot face before possible deformation is flat and parallel to the tubes TUB. The angle θ can be determined with reference to a plane P perpendicular to the plane of the hot face.

Depth

The deformation evoked in the direction of the length and in the direction of the width of a brick can induce a deformation in the direction of the depth and lead to generate constraints by support between the brick CF and the tubes.

For this purpose, it can be expected that the depth of the brick D_p at its periphery is less than or equal to the depth D_h of the brick in its heart. There is therefore a thickness recess D_c at the periphery of the brick, such that D_h = D_p + D_c. on the figure 1 and on the figure 2 , the recess is shown with a constant thickness D_c (at least in cross-section) between the periphery and the recess configured to conform to the shape of at least one tube. It is also possible to provide a recess of variable thickness D_c in at least one direction, for example in the form of a bevel.

By depth D_h of the brick in its heart, we mean the maximum thickness of the brick, regardless of the thickness of the blind housing.

Thus, the brick feet, that is to say the depth of the brick D_p at its periphery, are shorter than the maximum height of the brick between the tubes so as to compensate for the horizontal cleavage generated by the swelling of the brick. hot face.

First embodiment

A first embodiment of brick is illustrated on the Figures 1 to 3 , in which the brick is inscribed in a polyhedron which is a rectangular parallelepiped.

By convention, and to simplify the present description, it is considered that this brick is configured to be arranged against vertical pipes.

The figure 1 is a cross section of the brick shown in figure 2 , and the figure 3 is a longitudinal section of the brick illustrated in figure 2 .

The figure 3 illustrates, in top view, the lower face DW or the upper face UP of the brick 100, equipped with a groove 101 for a joint between adjacent bricks.

Preferably, the brick 100 has a longitudinal plane of symmetry (AA section of the figure 2 ).

The brick comprises at least one recess 102 configured to conform to the shape of at least one tube, as well as a blind housing 103 for fixing the brick to an individual fixing device (in dashed line on the figure 2 ).

The present cold face CF is at least partially in a PP plane. The brick 100 has plane recesses at the periphery which, in longitudinal section ( figure 3 ), are beveled angle α with respect to the plane PP. Preferably, the bevels of angle α are symmetrical.

Thus, the cold face (rear) in contact with the tubes have two plane inclined at an angle α, symmetrical on two opposite faces, the value of the angle α is for example between 0 to 15 °, so as to compensate the vertical cleavage generated by swelling in the hot face and limit the stresses exerted by the shaped part on the exchanger tubes.

The upper face UP, like the lower face DW, preferably has at least one plane portion whose angle is at least 90 ° relative to a hot face HF plane. In this case, see Figure 1 and Figure 2 , the upper face UP and the lower face DW both have a flat part (not referenced) substantially perpendicular to the hot face HF and the cold face CF, a grouting groove 101 and a flat part whose angle is greater than 90 ° with respect to the hot face HF, so as to create an angle bevel θ. Preferably, the bevel angle θ illustrated in cross section ( figure 1 ) is the same as the angle bevel θ shown in longitudinal section ( figure 3 ). It is assumed that the deformation of the brick is the same in the direction of the length and in the direction of the width (with equal thickness).

In this first embodiment, the brick comprises a first plane of symmetry: the plane cut AA of the figure 2 . Excluding the blind housing 103, the brick includes a second plane of symmetry: the plane cuts BB of the figure 2 .

Second embodiment

A second embodiment of brick is illustrated on the Figures 4 to 6 , in which the brick is inscribed in a polyhedron which is a non-rectangular parallelepiped, in this case a non-right prism.

By convention, and to simplify the present description, it is considered that this brick 200 is configured to be disposed against vertical pipes.

It is equipped with a groove 201 for a joint between adjacent bricks.

Preferably, the brick 200 has a longitudinal plane of symmetry (AA section of the figure 5 ).

The brick comprises at least one recess 202 configured to conform to the shape of at least one tube, as well as a blind housing 203 for securing the brick to an individual fixture (dashed on the figure 5 ).

The present cold face CF is at least partially in a PP plane. Brick 200 has peripheral recesses which, in longitudinal section ( figure 6 ), are beveled angle α with respect to the plane PP.

In the second embodiment, the periphery of the brick 200 is defined for example as between the end thereof and the point of inflection between the angle bevel α with respect to the plane PP and the upper face UP (see figure 6 ).

With respect to the first embodiment, the plane in which the upper face UP is also parallel to the plane in which the lower face DW is inscribed, but in longitudinal section, none of these planes is perpendicular to the hot face. HF or cold face CF.

Preferably, the seal groove 201 has two 45 ° struts which facilitates demolding of the brick during its manufacture.

In this second embodiment, the brick comprises a plane of symmetry: the plane cut AA of the figure 5 .

From a general point of view, preferably at least a portion of the cold face CF is in a plane, which facilitates for example the manufacture of bricks.

It can be provided that the plane in which at least part of the cold face is part is parallel to the hot face, which facilitates for example the manufacture and transport of bricks.

The invention is not limited to the previously described embodiments. For example, provision may be made to use silicon carbide bricks with a nitride or oxy-nitride bond; knowing that these deform less than those with oxide bond.

There is illustrated a substantially flat hot face, which facilitates the flow of fumes along this face. However, it can be provided that the hot face has a relief, for example corrugations (in cross-section) or a shape that conforms to the shape of at least one tube in the cold face and in the hot face, so that the thickness of the brick is substantially constant (regardless of the thickness of the blind housing).

Claims (8)

1. Refractory brick (100, 200) for a wall of a static combustion chamber subjected to corrosive atmospheres, the refractory brick comprising:

   - a hot face (HF) having a width (W_h) and a length (L_h) and intended to be exposed to combustion fumes; and

   - a cold face (CF), opposite the hot face (HF), having a width (W_c) and a length (L_c), and intended to be in the vicinity of or in contact with at least one tube intended for the flow of a heat transfer fluid;

   the length (L_h) of the hot face being less than the length (L_c) of the cold face, in such a way that at least two opposite lateral faces have a bevel of angle θ,
   characterised in that the width (W_h) of the hot face is less than the width (W_c) of the cold face,
   in that the cold face (CF) is provided with a blind housing (103, 203) in order to fasten the refractory brick to a device for fastening the wall,
   and in that the cold face (CF) has two symmetrical planes each inclined by an angle α with respect to a plane (PP) in which said cold face (CF) is inscribed at least partially.
2. Refractory brick according to claim 1, characterised in that the hot face (HF) is undulated.
3. Refractory brick according to claim 1, characterised in that the cold face (CF) has at least one recess (102, 202) configured to hug the shape of said at least one tube, and
   in that the hot face (HF) has a shape that also hugs said at least one tube, in such a way that the thickness of the refractory brick is substantially constant independently of a thickness of the blind housing (103, 203).
4. Refractory brick according to any preceding claim, characterised in that the value of the difference between the width (W_h) of the hot face and the width (W_c) of the cold face is greater than or equal to the value of the deformation of the hot face (HF) in the direction of said width in the conditions of use of said refractory brick, and
   in that the value of the difference between the length (L_h) of the hot face and the length (L_c) of the cold face is greater than or equal to the value of the deformation of the hot face (HF) in the direction of said length in the conditions of use of said refractory brick.
5. Refractory brick according to any preceding claim, characterised in that it comprises a material with a silicon carbide base, and
   in that the silicon carbide is an oxide, nitride or oxy-nitride bond.
6. Refractory brick according to any preceding claim, characterised in that the depth (D_p) of the refractory brick at its periphery is less than or equal to the depth (D_h) of the refractory brick at its core.
7. Static combustion chamber or oven able to be subjected to corrosive atmospheres, comprising a plurality of refractory bricks (100, 200) according to any of claims 1 to 6.
8. Use of a set of refractory bricks (100, 200) according to any of claims 1 to 6 to form a wall in a static combustion chamber or oven according to claim 7, said static combustion chamber or oven able to be subjected to a corrosive atmosphere due to the combustion fumes and comprising at least one tube intended for the flow of a heat transfer fluid, said wall having a hot face subjected to said corrosive atmosphere and a cold face, opposite said hot face, located in the vicinity of or in contact with said tube.

Images