Burner, apparatus and method for firing ceramic articles

Abstract

A burner (1) for firing ceramic articles (T) comprises: a mixing body (5) which in turn comprises at least one duct (6) for feeding a fuel (FL) and at least one duct (7) for feeding an oxidizing agent (OX); a spark device (8) for initiating the combustion; a flame detection device (9); a first tubular discharge element (11) configured to be passed through by the fluid (F) flowing out of the mixing body (5) and provided with a first end (12) into which at least a portion of the mixing body (5) is inserted and a second end (14) opposite the first end (12); and an introduction element configured to inject fuel (FL) downstream of the first tubular discharge element (11), in the region of the second end (14) or in a region protruding from the second end (14).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims the priority of Italian Patent Application No. 102022000015384 filed on July 21, 2022, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The present invention relates to a burner and an apparatus for firing ceramic articles.

[0004] In particular, the invention applies advantageously, but not exclusively, to the firing of ceramic articles to obtain tiles, to which the following description will make explicit reference without loss of generality. Background Art

[0005] The firing of ceramic products to obtain tiles is usually carried out in a tunnel kiln, which is delimited by two opposing walls and a roof. Such a kiln is usually heated by two sets of burners, each set of burners being arranged on one side of the tunnel.

[0006] Typically, burners running on natural gas (eg methane) are located at several levels on the side walls of the tunnel and facing the opposite wall.

[0007] The firing cycle of ceramic objects is designed with great precision and involves heating the ceramic objects from the kiln entrance, keeping them at a predetermined temperature within the firing chamber, and cooling them in a controlled manner before reaching the kiln exit.

[0008] Typically, ceramic products are transported on large conveyors consisting of a series of ceramic rollers. It is therefore important to ensure that the temperature within the firing chamber is uniform across the width of the kiln.

[0009] For this purpose, different types of industrial burners as well as different burner arrangements within complex plants have been developed in order to achieve increasingly constant temperatures in the firing chamber. Especially in very wide tunnel kilns, there is often an inhomogeneous temperature distribution in different cross sections and there are local temperature peaks that are determined by the position of the burners.

[0010] In order to overcome the above-mentioned problems, various types of so-called "high-velocity" burners have been developed which feed the combustion fumes (and flames) deep into the firing chamber in order to improve the heat exchange inside it.

[0011] However, as mentioned above, ceramic burners of known type are essentially fueled by fossil fuels (methane, LPG), resulting in an anti-ecological use of non-renewable resources. For this reason, various "environmentally sustainable" solutions are being considered, such as the use of non-fossil fuels, including hydrogen.

[0012] However, today, the use of hydrogen is hampered by several factors. Firstly, this fuel leads to high temperature peaks, which even compared to fossil fuels, lead to an increase in NOx production. In addition, hydrogen generally produces a highly unstable flame, which leads to very high flashbacks compared to methane (or LPG) and therefore to a highly delayed flame front (near the fuel supply pipe), which leads to overheating of the burner and the risk of causing an uncontrolled explosion, which can damage the burner itself and the firing equipment.

[0013] In an attempt to overcome these problems, the Applicant filed Italian patent application 102021000013535 for a burner equipped with an oxidant distribution system. However, this burner does not allow the use of flameless burning mode for a long time, since, especially when using pure hydrogen as fuel, after a certain time the flame tends to reappear, producing dangerous detonations inside the burner, making flame burning preferred in any case.

[0014] All these factors lead in particular to non-uniform temperatures in the kiln, which inevitably lead to firing defects in the ceramic products. In particular, the defects are both size- and shape-related, such as lack of flatness. This leads to waste, energy consumption and increased emissions.

[0015] The object of the present invention is to provide a device, a burner and a method which at least partially overcome the disadvantages of the prior art and which are simple and economical to implement. Summary of the invention

[0016] According to the present invention, there is provided a burner, an apparatus and a method for firing ceramic articles as claimed in the accompanying independent claims and preferably in any claim directly or indirectly dependent on the independent claims.

[0017] The claims describe preferred embodiments of the invention which form an integral part of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The invention will now be described with reference to the accompanying drawings showing some non-limiting embodiments of the invention, in which:

[0019] - Figure 1 is a front view in section of a first embodiment of the apparatus according to the present invention;

[0020] - Figure 2 is a schematic plan view of a portion of a second embodiment of an apparatus according to the invention;

[0021] - Figure 3 A burner according to the present invention is Figure 1 A perspective schematic diagram of a portion of a device;

[0022] - Figure 4 yes Figure 3 a front view of a section of a portion;

[0023] - Figure 5 yes Figure 3 a plan view of a section of a part;

[0024] - Figure 6 yes Figure 3 A three-dimensional schematic diagram of a portion of a burner;

[0025] - Figure 7 yes Figure 6 A detailed longitudinal cross-sectional view of a burner;

[0026] - Figure 8 yes Figure 3 A cross-sectional front view of a combustion head of a burner in FIG.

[0027] - Fig. 9 and Fig.10 yes Figure 8 Two sectional front views of a portion of a combustion head;

[0028] - Fig.11 a graph showing the temperature of the combustion products of the burner along its axis as a function of distance from the kiln wall comparing a burner operating in a flame mode and a burner operating in a non-flame mode; and

[0029] - Fig.12 A graph showing a comparison of NOx generation (chamber temperature of 900° C.) as a function of fuel flow (particularly pure hydrogen) in a burner operating in a flame mode and a burner operating in a non-flame mode is shown. DETAILED DESCRIPTION

[0030] exist Figure 1 1 generally denotes a burner for firing ceramic products T according to a first aspect of the present invention.

[0031] The burner 1 may preferably, but not necessarily, be installed in an industrial kiln 2 comprising a firing chamber 3 , in particular a tunnel kiln.

[0032] In particular, if Figure 1 and Figure 2 As shown, the transport system 4 moves the ceramic articles T along a transport path P.

[0033] More precisely, the ceramic article T is any type of ceramic article requiring at least one firing cycle in a kiln.

[0034] exist Figure 1 and Figure 2In a non-limiting embodiment, the transport system 4 comprises a conveyor belt on which the unfired ceramic articles T to be fired are preferably arranged in an orderly manner.

[0035] According to some non-limiting, not illustrated embodiments, the transport system 4 comprises a plurality of ceramic rollers (possibly also moving at different speeds in order to differentiate the firing of the articles).

[0036] Advantageously but not limitingly, the burner 1 is configured to fire the ceramic T product in flameless mode.

[0037] like Figures 1 to 6 As shown, the burner 1 comprises a mixing body 5, which in turn comprises a conduit 6 for supplying a fuel FL having a certain percentage of hydrogen (in particular greater than 50%, more precisely greater than 70%, preferably completely hydrogen), a conduit 7 for supplying an oxidant, a spark device 8 for starting the combustion and a flame detection device 9. In other words, the mixing body 5 is the part of the burner required to generate the mixture of air and gas that (after obtaining the spark of the flame) will heat the firing chamber 3.

[0038] In particular, the fuel FL is a gaseous fuel.

[0039] In particular, the fuel FL injected via the fuel supply conduit 6 is mainly hydrogen (possibly mixed with natural gas or LPG such as methane), while the oxidant OX injected via the oxidant supply conduit 7 is essentially ambient air (with about, for example, 21% oxygen). Preferably, but not limitingly, the oxidant OX is preheated, in particular to a temperature above 100° C., in particular to a temperature between 130° C. and 300° C., more particularly to a temperature between 150° C. and 250° C.

[0040] The burner 1 further comprises a tubular discharge element 11 suitable for (configured to be) traversed by the fluid F (formed by the mixture of the fuel FL and the oxidant OX and / or the combustion thereof, if any) flowing out of the mixing body 5 and having an end 12 with an opening 13 and an end 14 opposite to the end 12 and with an opening 15, into which at least a portion of the mixing body 5 is inserted. In other words, the end 14 faces the firing chamber 3.

[0041] According to some non-limiting embodiments, the mixing body 5 is coupled to the tubular discharge element 11 by means of a fastening element. Advantageously but not necessarily, as in Figure 4 and Figure 5 In the embodiment shown, the fastening element is a bolt 16 .

[0042] exist Figure 3 , Figure 4 and Figure 5In the non-limiting embodiment shown, the mixing chamber 5 is partially inserted into the discharge element 11 and partially arranged outside the kiln 2. In particular, Figure 4 and Figure 5 In an embodiment, the discharge element 11 is inserted into the side wall 17 of the tunnel kiln 2. More precisely, the discharge element 11 extends completely inside the side wall 17. On the other hand, in other non-limiting embodiments, the discharge element 11 extends along the entire length of the side wall 17, partially entering the firing chamber 3 of the kiln 2.

[0043] Advantageously, the burner comprises an introduction element 18 configured to inject the fuel FL downstream of the tubular discharge element 11 at the second end 14 or, as shown in the non-limiting embodiment of the figures, to project from the second end 14 into the firing chamber 3 .

[0044] In detail, the introduction element 18 is configured to introduce the fuel FL directly into the firing chamber 3 , ie not into the tubular discharge element 11 .

[0045] In particular, the introduction element 18 is (fluidically) separated from the mixing body 5 .

[0046] In particular, the introduction element 18 is fluidically separated from the interior of the tubular discharge element 11 .

[0047] Thus, advantageously but not limitingly, the fuel FL introduced into the firing chamber 3 does not come into contact with the oxidizing agent OX inside the tubular discharge element 11 but simply leaves it, ie downstream thereof.

[0048] exist Figures 3 to 7 In a non-limiting embodiment, the introduction element 18 comprises a tubular duct 19 extending at least from the end 12 to the end 14, in particular from the opening 13 to the opening 15 of the tubular discharge element 11. In particular, the introduction element 18 is configured to feed the fuel FL directly into the firing chamber 3 downstream of the tubular discharge element 11.

[0049] According to some preferred but non-limiting embodiments, the tubular element 18 passes longitudinally through the tubular discharge element 11 from one side to the other.

[0050] In some non-limiting cases, the burner 1 comprises only one introduction element 18 .

[0051] In other non-limiting aspects, the burner 1 comprises a plurality of introduction elements 18 .

[0052] Preferably, if Figures 4 to 6 The introduction element 18 also extends into the tubular discharge element 11. Thus, the burner 1 can be used to replace a standard burner without making any significant changes to the kiln 2.

[0053] In other non-limiting forms, not shown, the introduction element 18 extends outside the tubular discharge element 11. In particular, the introduction element 18 is mounted to / inserted from the side wall 17 of the kiln 2 (by means of appropriate openings / holes and any insulating and / or supporting elements) and, in any case, is configured to supply the fuel FL directly downstream of the tubular discharge element 11. In this way, the burner 1 can still be operated in a flameless mode by taking advantage of the introduction of the fuel FL directly into the firing chamber 3 and thus avoiding the reformation of the flame front inside the tubular discharge element 11, although not interchangeable with existing burners.

[0054] Advantageously, but not limitingly, the burner 1 is configured to operate in a flame mode initially (i.e., in the presence of a flame front (as is conventionally the case with ceramic systems)) and after reaching a predetermined temperature (i.e., a temperature greater than or equal to the auto-ignition temperature of the fuel-oxidant mixture to be introduced into the kiln).

[0055] Advantageously, but not limitingly, the introduction element 18 is configured to supply the fuel FL into the firing chamber 3 instead of the fuel FL supply conduit 6. In other words, the introduction element 18 is configured to instead introduce the fuel FL into the firing chamber 3 when the burner 1 is operated in a flameless mode, i.e., without causing the generation of a flame front (i.e., a limited area, typically less than one millimeter, where the combustion reaction occurs in the flame mode).

[0056] In some preferred non-limiting cases, such as Figures 4 to 7 The cases shown in detail are Figure 5 As can be seen in Figure 1 , the tubular duct 19 extends asymmetrically with respect to the longitudinal symmetry axis AA of the burner 1. In particular, the tubular duct 19 extends at least partially parallel to the inner wall 20 of the tubular discharge element 11. In other words, the tubular duct 19 does not extend along the longitudinal symmetry axis AA. The asymmetry of the arrangement of the tubular duct 19 (in detail, its offset arrangement towards the wall 20) makes it possible to reduce thermal stresses during flame mode operation, and thus protect it. In fact, as a result, the duct 19 is less immersed in the flame.

[0057] Advantageously, but not limitingly, the tubular duct 19 follows the course of an inner wall 20 which has a narrowing 21 at the opening 15. In particular, the tubular duct 19 comprises at least one straight portion 22 and one straight portion 23 connected to each other by a straight portion 24 of the tubular duct 19 itself. In detail, the straight portion 22 is arranged radially at a greater distance from the longitudinal axis of symmetry AA than the straight portion 23. In this way, the tubular duct 19 is subjected to greater stresses only on the straight portion 23 which preferably passes through the opening 15 and protrudes into the firing chamber 3. Thus, advantageously, but not limitingly, the curved portion 24 is placed close to the opening 15, i.e. at a distance less than 20 cm, in particular less than 15 cm, from the opening 15.

[0058] Advantageously, but not necessarily, to allow the fuel FL to penetrate deep into the firing chamber 3 during the flameless mode, the tubular conduit 19 has an inner ID diameter, ie, lumen, less than or equal to 10 mm, particularly less than or equal to 7 mm, more particularly less than or equal to 5 mm.

[0059] exist Figures 4 to 6 In a non-limiting embodiment of the invention, the introduction element 18 comprises an end 25 which protrudes from the opening 15 by a distance greater than or equal to 5 mm, in particular greater than or equal to 10 mm, preferably between 10 mm and 20 mm. In this way, the fuel FL can be introduced into the firing chamber 3 (during flameless combustion) so as to reduce the risk of propagating the combustion back into the tubular discharge element 11 (regenerating the flame front and, in particular in the case of hydrogen as fuel FL, generating dangerous detonations inside the burner 1).

[0060] In certain non-limiting circumstances, and if Figure 5 As shown in the embodiment of the burner 1, the burner 1 includes a fuel FL supply system 26 connected to the fuel FL supply pipe 6 and a fuel FL supply system 27 connected to the introduction element 18 separately from the fuel FL supply system 26. In particular, the fuel FL supply system 26 and the fuel FL supply system 27 can be operated selectively and / or independently of each other, for example by means of a special solenoid valve 28 (preferably redundant for safety reasons).

[0061] Advantageously, but not necessarily, such as Figure 5 As shown, both the fuel FL supply system 26 and the fuel FL supply system 27 are connected to different ducts 6 , 6 ′ obtained on the breech 29 of the mixing body 5 .

[0062] In other non-limiting cases not shown, the fuel FL supply system 26 and the fuel FL supply system 27 are connected to the same pipe 6 on the rear chamber 29, which pipe 6 is equipped with a diverter valve that supplies the fuel FL to the mixing body 5 or the introduction element 18 depending on the operating mode of the burner 1 (flame or no flame).

[0063] Some advantageous but non-limiting features are described below during the flame operating mode of the burner 1. These characteristics combine synergistically with the rest of the description to allow the use of 100% hydrogen or at least a high percentage of hydrogen fuel.

[0064] Advantageously but not limitingly, and as Figures 4 to 8 As shown in the non-limiting embodiment, the mixing body 5 includes a fuel FL distribution system FPS and an oxidant OX distribution system OPS, the fuel FL distribution system FPS is configured to divide the fuel FL into a plurality of parts FL', FL", FL"', and the oxidant OX distribution system OPS is configured to divide the oxidant OX into a plurality of parts OX', OX", OX"' (see, for example Figure 8 ). The burner 1 is configured so that a plurality of FL', FL", FL"' and a plurality of parts OX', OX", OX"' are delivered so that they are mixed with each other (forming respective mixtures M', M", M"') in at least two (particularly three or more) stages. Thus, when the fuel FL is mainly or entirely hydrogen, flame generation is suppressed and controlled.

[0065] Advantageously, but not necessarily, the oxidant distribution system OPS comprises a combustion head 10, which is (at least partially) arranged inside the first tubular discharge element 11 (through the opening 13) and comprises one or more combustion chambers 30, 31, each combustion chamber 30, 31 being configured to accommodate a different stage of flame combustion (or mixture M1, M2).

[0066] Advantageously, but not necessarily, the fuel FL distribution system FPS comprises an injection element 32 configured to inject at least a majority FL'' of the fuel FL downstream of the burner head 10 (inside the tubular discharge element 11) towards the end 14 (i.e. towards the firing chamber 3) during flame combustion. In this way, a majority of the flame is generated away from the end 12 of the burner 1, while bringing the flame front closer to the firing chamber and reducing overheating of the mixing body and the discharge element 11.

[0067] In particular, the tubular discharge element 11 is configured to contain a primary stage F' of flame combustion.

[0068] according to Figures 4 to 10In the preferred but non-limiting embodiment shown, the injection element comprises a tubular duct 33, which is in particular axial (i.e. arranged at the longitudinal axis AA of the burner 1) and which passes from one side to the other through one or more combustion chambers 30, 31 so as to convey a portion FL"' (greater than 50%, preferably 70% to 80%) of the fuel FL downstream of the combustion head 10, so that most of the flame is directed towards the firing chamber 3.

[0069] exist Figures 4 to 10 In a non-limiting embodiment, the tubular duct 33 has a substantially constant cross section, which is preferably circular. In particular, the tubular duct has a first cross section, the inner diameter of which ranges from 2 mm to 12 mm, in particular from 4 mm to 10 mm. In this way, a high speed can be ensured that is conducive to reducing / controlling flashback (which is usually problematic in the case of hydrogen), and it can also help the rest of the burner to reach the speed required for introducing the flue gas F deep into the chamber 3.

[0070] In some non-limiting cases, such as Figures 4 to 10 In the case shown, the tubular duct 33 comprises an end 34 connected to the fuel FL supply duct 6 and an end 34 ′ inside the tubular discharge element 11 towards the end 14 .

[0071] In certain non-limiting cases, the tubular conduit 33 is configured so that one end 34 is held within the tubular discharge element 11. In particular, the tubular conduit 33 is configured to be held in the half of the tubular discharge element 11 that is farthest from the firing chamber 3 (i.e., from the end 14), more specifically, the end 34 is located at the end of the burner head 10 (in particular aligned with the end of the burner head 10). More specifically, the tubular conduit 33 has a length of 40 mm to 150 mm, preferably 60 mm to 110 mm.

[0072] Advantageously, but not necessarily, such as Figure 7 , Fig. 9 and Fig.10 As shown in the non-limiting embodiment of the present invention, the tubular duct 33 has one or more openings 35 for distributing the fuel FL at each combustion chamber 30, 31 so as to inject at least one of the parts FL', FL" into each of the combustion chambers 30, 31. In particular, the one or more distribution openings 35 are through holes 36 that connect the inner area of ​​the tubular duct 33 to the combustion chambers 30, 31.

[0073] Advantageously, but not necessarily, the through hole 36 is a radial hole, preferably annular, for example extending radially from the axis AA. Preferably, the diameter of the hole 36 is less than 5 mm, in particular from 1 mm to 3 mm.

[0074] Advantageously, but not necessarily, the fuel FL supply duct 6 comprises at least a narrow portion 37 of the type described in Italian patent application 102021000013535 in the name of the Applicant.

[0075] Advantageously, but not necessarily, the burner 1 (mixing body 5) comprises a rear chamber 29 (in particular made of aluminium or cast iron and provided with the last part of the channels 6 and 7 for supplying the oxidant and the fuel) closing the burner 1 from the side opposite the firing chamber 3. In particular, the rear chamber 29 is of the type described in Italian patent application 102021000013535 by the same applicant, except for the duct 6' to which the system 27 for the supply of fuel and therefore the fuel introduction element 18 is connected in flameless mode.

[0076] Advantageously, but not necessarily, and as Figures 1 to 4 In the non-limiting embodiment shown in FIG. 1 , the burner 1 includes a tubular discharge element 38 (e.g., Figure 4 The tubular discharge element 38 (shown in dashed lines in FIG. 1 ) extends from the end 14 of the element 11 in a direction opposite to the end 12 , ie towards the firing chamber 3 (more precisely, the interior of the firing chamber 3 ) .

[0077] In some non-limiting cases, the burner 1 comprises a suction element 39 suitable for (configured to) convey at least a portion of the gas G present outside the burner 1 .

[0078] Preferably, the discharge element 38 and the suction element 39 are of the type described in Italian patent application 102021000013535 of the same applicant. In particular, the discharge element 38 and the suction element 39 form, together with the discharge element 11, a combustion block of the type described in Italian patent application 102021000013535 of the same applicant.

[0079] Advantageously and quite unlike the standards used in the ceramic market, the burner head 10 is a multi-stage burner head, ie adapted (configured) to divide the flame formation into several stages. This makes it possible to use the so-called "air staging" technique.

[0080] Advantageously and significantly different from the standards used in the ceramic market, the ducts 33 together with the openings 35 help the burner head 10 to separate the flame into different stages, in particular by separating the fuel FL. In this way, the so-called "fuel staging" technique can be used.

[0081] According to the combination of the above techniques, it is possible to use a fuel FL with a significant percentage of hydrogen while increasing the flame speed to more than 160 m / s, in particular up to more than 180 m / s, more precisely up to about 200 m / s. In fact, the term "high speed" means, in particular for burners, that the flame speed is 150 m / s or more.

[0082] Advantageously, but not necessarily, the burner head 10 (with the tubular duct 33 inside it) is at least partially mounted inside the tubular discharge element 11 so as to be coaxial with the tubular discharge element 11 along the longitudinal axis of symmetry AA of the burner 1 .

[0083] like Figures 4 to 10 As shown in the non-limiting embodiment of the multi-stage burner head 10, advantageously, the multi-stage burner head 10 comprises (at least) a combustion chamber 30 and (at least) a combustion chamber 31, the combustion chamber 30 being suitable (configured to) produce a first combustion stage of the flame given by the combination of the portions FL' and OX' (in particular to produce the so-called flame "root"), the combustion chamber 31 being in communication with the combustion chamber 30 and being suitable (configured to) produce a second combustion stage of the flame (given by the combination of the portions FL" and OX") leaving the combustion chamber 30. In particular, the combustion chambers 30 and 31 are configured to convey the secondary portion F" (or secondary state) of the flame within the tubular discharge element 11 towards the end 14 and, in particular, towards the tubular discharge element 38 via the suction element 39.

[0084] exist Fig. 9 and Fig.10 In a non-limiting embodiment of the invention, in which two sections of the multistage burner head 10 are shown in detail, the combustion chamber 30 comprises at least one inlet opening 40 and one outlet opening 41 (more precisely arranged on opposite sides of the combustion chamber 30 ). The outlet opening 41 faces the firing chamber 3 .

[0085] In certain preferred non-limiting cases, the burner 1 comprises an additional fuel FL distribution opening 42 (particularly of the portion FL') connecting the fuel FL supply conduit 6 to the combustion chamber 30. In particular, the additional opening 42 for supplying the fuel FL comprises an axial through hole 43, which is preferably arranged in the crown (along mutually parallel directions) around the longitudinal symmetry axis AA of the burner 1. More specifically, the additional opening 42 is formed on the inlet opening 40, which is suitable for (configured to) communicate with the conduit 6 for supplying the fuel FL and receive a volume flow of the fuel FL (more precisely, the volume flow is variable). Preferably, the diameter of the hole 43 is less than 5 mm, in particular 1 mm to 3 mm.

[0086] Advantageously, but not necessarily, upstream of the combustion chamber 30 , the mixing body comprises a first distribution chamber 44 configured to inject, during an operating mode with a burner flame 1 , a portion of the fuel FL passing through it via the further openings 42 and to inject the remainder via the end 34 into the tubular duct 33 .

[0087] exist Figures 4 to 10 In a non-limiting embodiment, the burner 1 comprises a combustion chamber 31, which is arranged downstream of the combustion chamber 30 and has an inlet opening 45 and an outlet opening 46 opposite to each other. The inlet opening 45 is configured to communicate with the outlet opening 41 and receive the oxidant-fuel mixture M'. In particular, the outlet opening 46 faces the firing chamber 3.

[0088] exist Figures 6 to 10 In a non-limiting embodiment, the burner head 10 comprises a crown 47 configured to regulate the inlet of the oxidant OX into the tubular discharge element 11, which does not pass through the combustion chambers 30 and 31. In particular, the crown 47 extends from the edge of the outlet opening 46 towards (up to) the inner wall of the tubular discharge element 11.

[0089] Advantageously, but not necessarily, the crown 47 comprises a slot 48 (or any other type of opening) configured to convey a portion of the oxidant OX'' into the tubular discharge element 11 downstream of the combustion chambers 30 and 31. Thus, together with the oxidant-fuel mixture M'' and the main portion FL'' of the fuel, a mixture M''' is produced at the outlet of the tubular discharge element 11, possibly through the suction element 39 towards the tubular discharge element 38. In particular, a primary flame F' of the burner 1 is produced.

[0090] Preferably, but not limitingly, the tubular duct 19 passes through the crown 47 , in particular through a slot 48 .

[0091] Advantageously, but not necessarily, the diameter of the narrowing 21 is less than 30 mm, in particular less than or equal to 25 mm. In detail, the diameter of the narrowing 21 is comprised between 5 mm (in particular 10 mm; more in particular 20 mm) and 60 mm (in particular 40 mm; more in particular 30 mm). This feature also allows the fluid F leaving the burner 1 to be accelerated, counteracting flashback and thus better managing the combustion with a very hydrogen-rich fuel FL mixture.

[0092] According to a preferred but non-limiting embodiment, Figures 4 to 8 As shown, the flame detection device 9 comprises a UV detection probe 49. In particular, the UV probe 49 is arranged at the edge of the breech 29, ie at the edge of the mixing body 5, along the longitudinal axis AA of the burner.

[0093] Advantageously, but not necessarily, the flame detection device 9 (more precisely, the UV detection probe 49) is configured to receive a UV beam (ultraviolet radiation) from the flame passing through the tubular discharge element 11. In use, the UV detection probe 49 provides data on the state of the flame generated by the burner, by which the flow of fuel FL and / or oxidant OX can be adjusted accordingly. Furthermore, once the flameless mode is activated as described below, the UV probe 49 is disabled, since it is no longer able to detect any flame, the flame front being diluted inside the firing chamber 3 of the kiln.

[0094] According to a second aspect of the invention, there is provided an industrial plant 50 for firing a ceramic article T, in particular as described above.

[0095] According to some non-limiting embodiments, once fired, the ceramic article T is a tile. In particular, the ceramic article T is unfired at the inlet of the device 50 and fired at the outlet.

[0096] The industrial plant 50 comprises a kiln 2 (as described above), in particular a tunnel kiln, having at least one side wall 17 delimiting a firing chamber 3 and having a surface 51 inside the firing chamber 3 and a surface 52 outside the firing chamber 3 .

[0097] The industrial plant 50 further comprises the above-mentioned transport system 4 , in particular a horizontal transport system 4 , which is configured to move a plurality of ceramic articles T along a conveying path P inside the firing chamber 3 (from the inlet to the outlet of the firing chamber 3 ).

[0098] Advantageously, but not limitingly, the device 50 comprises a (hydrogen) burner 1 as described above.

[0099] Advantageously, the device 50 comprises a hydrogen supply system S configured to inject hydrogen or a mixture containing hydrogen into the fuel FL supply systems 26 and 27. In particular, the hydrogen supply system S is configured to selectively (ie, exclusively) inject hydrogen or a mixture containing hydrogen into the fuel supply pipe 6 or the introduction element 18.

[0100] In particular, during the flameless operating mode, all the fuel FL passes through the introduction system 18 while preferably all the oxidant OX passes through the discharge element 11 before being mixed into the mixture M* directly in the firing chamber 3 without generating a localized, and therefore flameless, flame front.

[0101] according to Figure 2 In a non-limiting embodiment of the present invention, the device 50 comprises a plurality of burners 1 arranged in series along a direction DD parallel to the conveying path P. In particular, the burners 1 are arranged at several levels in at least one wall 17 of the kiln 2 .

[0102] exist Figures 1 to 4In a non-limiting embodiment, the burner 1 is coupled to the wall 17 of the kiln 2 via the fastening element 16. In particular, the discharge element 11 is inserted into the wall 17. Thus, the burner according to the invention is facilitated because it substantially preserves the dimensions of a ceramic kiln burner.

[0103] exist Figure 1 In a non-limiting embodiment of the invention, the burner 1 is oriented in a direction DP transversely (in particular perpendicularly) to the direction DD (and therefore transversely to the conveying path P).

[0104] Advantageously, but not necessarily, the tubular element 11 of the burner 1 is mounted so that it at least partially, in particular completely and laterally, passes through one side wall 17 of the kiln 2. In this way, the flame generated by the burner 1 will flow directly to the inside of the firing chamber 3 of the kiln 2.

[0105] In particular, the axis AA is perpendicular to the conveying path P. More specifically, the axis AA is also perpendicular to the side wall 17 of the industrial tunnel kiln 2 .

[0106] According to certain non-limiting embodiments, not shown, the exhaust element 11 of the burner 1 is mounted so as to partially protrude into the firing chamber 3 .

[0107] Prior patents are incorporated by reference.

[0108] Advantageously, but not necessarily, the device 50 (or each burner 1 ) comprises at least one electronic control unit 53 configured to control the burner 1 so as to switch from a flame heating configuration of the firing chamber 3 to a flameless firing configuration.

[0109] In particular, the electronic control unit 53 is configured to control the burner 1 so that it switches from the flame mode to the non-flame mode when a predetermined temperature TV is reached. More precisely, the predetermined temperature TV is above the auto-ignition temperature of the fuel mixture M* (for example, above 800° C.). In this way, the mixture M* produced in the firing chamber 3 will be free of a flame front, with all the advantages that this brings, as described below.

[0110] By means of this control of the supply of oxidant OX and fuel FL to the burner 1, and the presence of the introduction element 18 for injecting the fuel directly into the firing chamber 3, flameless combustion can be achieved even with a fuel such as hydrogen, which tends to reform the flame front in an abrupt and undesirable manner inside the burner even at low capacities (where the flame pulse determines the establishment of conditions suitable for the formation of the flame front by reducing its intensity) if the flameless mode is prolonged over time. In particular, the electronic control unit 53 is configured to extinguish the flame once a predetermined temperature TV is reached in the firing chamber 3 by reducing or interrupting the supply of fuel FL and possibly (but not limitingly) oxidant OX to the fuel supply conduit 6 and the oxidant supply conduit 7, respectively. Once the flame is extinguished, the control unit 53 is configured to feed the fuel FL into the introduction element 18 (and to resume the supply of oxidant OX in the event that the oxidant OX is interrupted), thereby allowing the burner 1 to produce the mixture M* directly inside the firing chamber 3 and to fire the ceramic article T in flameless mode. Preferably, but not limiting, the control unit 53 is also configured to selectively inhibit flame control (via the detection device 9) during the flameless operating mode. By using flameless combustion, i.e. combustion with a temperature in the kiln above the auto-ignition temperature of the fuel, it is actually possible to significantly reduce NOx emissions normally produced in the combustion of hydrogen-rich mixtures (and usually by combustion with a high flame peak), thereby allowing the use of environmentally sustainable fuels with low emissions. In particular, the alternating combination of flame mode and non-flame mode compensates for the extreme ignition and propagation (flashback) of hydrogen.

[0111] In particular, but not limitingly, the electronic control unit 53 is configured to control the device 50 so that it fires the tiles T only in the flameless configuration.

[0112] Advantageously, but not necessarily, and as Figure 1 In a non-limiting embodiment, the device 50 comprises at least two temperature control devices 54, in particular at least two thermocouples 55 with double wires, arranged at at least two different "critical" points of the kiln 2. These two points make it possible to ensure that at every point in the firing chamber, the temperature is sufficiently above the auto-ignition temperature of the fuel mixture (thus allowing reliable flameless firing).

[0113] Advantageously, but not necessarily, if the temperature detected by the two thermocouples 55 drops below the auto-ignition temperature, the flame is triggered and ignites again, ie the electronic control unit 53 immediately resets the burner 1 to flame mode.

[0114] According to another aspect of the present invention, a method for firing a ceramic article delivered into a tunnel kiln is provided.

[0115] The method comprises at least one step of supplying a burner 1 as described above with a fuel FL containing at least 20% hydrogen, more particularly more than 50% hydrogen, more particularly more than 70% hydrogen, preferably all hydrogen. This fuel mixture can be used in flame operation mode due to the above-mentioned special burner geometry, in particular due to the combination of the multi-stage burner head 10 with the injection element 32. Moreover, the above-mentioned additional geometry synergistically leads to the important technical effect of reducing the environmental impact by allowing the use of hydrogen-rich fuel mixtures and reducing NOx, respectively.

[0116] In some non-limiting cases, the fuel FL contains more than 90% hydrogen. In particular, the fuel is 100% hydrogen.

[0117] The method further comprises the steps of simultaneously supplying the burner 1 with an oxidizing agent OX and igniting (igniting) a flame (via the spark device 8) extending at least partially into the burner 1 and the firing chamber 3 of the kiln 2 .

[0118] Once the flame has been ignited, the method controls the flame in detail in feedback with the aid of the detection device 9 until a predetermined temperature TV is reached in the firing chamber 3 .

[0119] Advantageously, but not necessarily, the method further comprises the steps of: extinguishing the flame by reducing (or interrupting) the supply of fuel FL and possibly oxidant OX, once the firing chamber 3 of the kiln 2 has reached a predetermined temperature TV (in particular, above the auto-ignition temperature of the fuel FL); preferably disabling the above-mentioned flame feedback control; and introducing the fuel FL into the introduction element 18 (i.e. into the tubular duct 19, possibly restoring the supply of oxidant OX), directly in the firing chamber 3, producing a mixture M* which determines the flameless combustion of the burning ceramic product T.

[0120] In particular, the method involves feeding the fuel FL directly into the firing chamber 3 through the introduction element 18. This reduces the risk of the burner 1 exploding due to a possible reignition of the flame inside it, in particular in the case of a very hydrogen-rich fuel FL.

[0121] In particular, the method involves switching from the flame mode to the no-flame mode when a predetermined temperature TV is reached. More precisely, the predetermined temperature TV is above the auto-ignition temperature of the fuel mixture.

[0122] Advantageously, but not necessarily, the method involves firing the tile T only after the flameless configuration has been reached. In other words, the burner 1 is supplied with the oxidant OX (via the discharge element 11) and the fuel FL (via the injection element 18), all without igniting a flame, by de-energizing and energizing (closing and opening) the solenoid valves 28 of the supply system 27 (in particular two solenoid valves 28 connected in series according to current regulations). At the same time, the air solenoid valve (not shown) is also temporarily closed.

[0123] In particular, the activation step of the solenoid valve 28 (i.e. the supply and interruption of the oxidant) is preferably carried out after the electronic control unit 53 has extinguished the flame in the burner 1 and suppressed the spark electrode 8 and the UV flame detection probe 49 (the flame front is no longer located in the burner 1, but is diluted in the chamber 3 of the kiln). More specifically, by means of the above-mentioned solenoid valves, the supply of the oxidant OX and the fuel FL is digitally controlled (on / off), i.e. by switching from maximum flow to zero and vice versa. This prevents the formation of a stable and anchored flame front in the burner 1. In detail, this effect is due to the fact that very high pulses are given to the flame supply, so that the flame front is not formed in the burner and is therefore directly diluted in the firing chamber 3.

[0124] In other non-limiting cases, according to the same principles explained above, the method involves maintaining the supply of oxidant OX via the control unit 53 and interrupting and subsequently supplying the duct 6 and the duct 19, respectively. In this way, constant pressure conditions can be maintained in the chamber 3 of the kiln 2 without swinging the flue gas chimney draught. A possible re-ignition of the flame front in the burner 1 is also prevented to a greater extent.

[0125] In the flameless phase, it is substantially diluted directly in the chamber 3 of the kiln 2, wherein the oxygen content of the combustion products already present in the chamber 3 is lower than that of the oxidant OX (for example, up to 14%, or even up to 4%, or even up to 2%, in order to make the flame front more inert). In other words, in this way, the oxidant OX and the fuel FL, which flow respectively from the burner 1 into the firing chamber 3, form a mixture M* which is oxidized inside the chamber 3 itself.

[0126] In this way, temperature peaks (which are one of the main causes of NOx generation) can be avoided compared to conventional flame-only solutions. This in turn leads to a lower thermal load on the components of the burner 1 (e.g. on the burner head 10, on the tubular ducts 19 and / or 33, on the mixing body 5, on the combustion block, on the fuel and oxidant pipes, etc.). At the same time, a strong reduction in the heat losses caused by the burner is thus achieved, thereby increasing the efficiency of the kiln 2. In addition, in the absence of a flame, the burner 1 will be quieter, thus also reducing the noise pollution generated by it.

[0127] In this regard, the above effects Fig.11 It is obvious that Fig.11 A graph comparing the temperature inside the kiln 2 (y-axis) as a function of distance from the wall 17 of the kiln 2 (x-axis) is shown for a burner 1 operating in flame mode FW and a burner operating in flameless mode FLS, respectively. The reduction in the initial temperature peak is evident, as is the higher temperature maintained deeper inside the firing chamber 3.

[0128] Consistently, Fig.12 A graph is shown showing a comparison of the NOx production (y-axis) as a function of the flow rate of fuel (hydrogen) (x-axis) in a burner 1 operating in flame mode FW and in a burner operating in flameless mode FLS. Again, the advantage in terms of emissions is evident regardless of the power of the burner 1.

[0129] Advantageously, but not necessarily, the power of the burner is less than 100 kW, in particular less than 70 kW, preferably less than 50 kW.

[0130] In use, the spark device 8 (in particular the spark electrode) generates a spark which, together with the fuel FL entering from the duct 6 and the oxidant OX entering from the duct 7, determines the generation of a flame. In particular, the portion OX' of the oxidant and the portion FL' of the fuel generate a mixture M' inside the combustion chamber 30, which mixture M' defines the first stage of the flame and continues to the combustion chamber 31, inside the combustion chamber 31, the mixture M', the portion FL" of the fuel and the portion OX" of the oxidant form a mixture M", which defines the second stage of the flame. The fluid F (and the primary flame F') is formed by the mixture M" inside the tubular discharge element 11 mixed with the portion OX"' of the oxidant OX and the portion FL"' of the fuel FL leaving the end 34'. Thus, the mixing body 5 generates an at least partially combusted mixture, i.e. a flame, whose fluid F flows through the tubular discharge element 11, which introduces the flame into the combustion chamber 3.

[0131] The combustion products discharged by the burner 1 are not completely burned on their first passage through the discharge element 11, but this combustion is increased (completed) by the continuous recirculation of the gas G (present inside the firing chamber 3) through the high velocity of the fluid F and possibly through the presence of the suction element 39. In other words, the burner 1 produces a primary combustion of the gases (fuel and oxidant) introduced by the ducts 6 and 7 by means of the spark device 8, and a secondary combustion with the recycled gas G coming from inside the firing chamber 3, which is not completely burned (there is residual oxygen therein) and is sucked in by the velocity of the fluid F and the suction element 39. In particular, the primary combustion takes place inside the discharge element 11 and the secondary combustion takes place inside the firing chamber 3.

[0132] Once the predetermined temperature TV is reached, the control unit 53 turns off the flame and reduces the supply of fuel FL to the introduction element 18, which introduces the fuel into the firing chamber 3 to produce the above-mentioned mixture M*. Generally, in order to achieve a good flameless combustion, it is convenient to dilute the mixture M* as much as possible. In particular, the burner 1 is configured to maintain a ratio between the amount of recycled flue gas and the sum of the amounts of introduced oxidant OX and fuel FL greater than 3. Under such conditions, the reformation of the flame front can be successfully avoided, so the flameless mode can be continued in a stable state.

[0133] It is thus clear that by using the device 50 or the set of burners 1 according to the invention, a greater temperature uniformity is obtained along the width of the firing chamber 3 of the kiln 2. In particular, the temperature close to the wall 3 is significantly increased due to the contribution of the turbulence generated by the suction element 39 (due to the additional speed allowed by the multi-stage burner head 10) and the radiation provided by the introduction element 18 close to the wall 3. In addition, due to the use of the introduction element 18, the temperature in the center of the kiln is increased relative to the traditional situation, which allows the combustion block 38 to reach a greater depth inside the kiln 2. Therefore, the flame coming out of the discharge element 14 is emitted deeper than in the traditional solution.

[0134] It is important to note that the temperature peak near the outlet of the burner 1 is also (at least partially) eliminated.

[0135] Although the invention described above makes particular reference to a very precise embodiment, it should not be considered limited to this embodiment, and all such variations, modifications or simplifications covered by the appended claims fall within its scope, such as a different geometry of the burner head 10, a different geometry of the introduction element 18 of the injection element 33, a different geometry of the chambers 30 and 31, a different geometry of the combustion block 38, in particular a different geometry of the suction element 39, a different method of suctioning the gas G near the inner surface 51 of the side wall 17, a different arrangement of the burner 1 in the device 50 (in terms of position and arrangement), a different transport system 4, etc.

[0136] The above-described apparatus and burner bring about numerous advantages.

[0137] Firstly, the construction and assembly of the burner 1 are simplified with respect to the solutions of the prior art, which comprise more parts and are therefore heavier and more voluminous, in addition to the complexity of the assembly. In addition, given the geometry of the burner 1 and the penetration into the firing chamber 3, the burner 1 can be safely installed as an alternative (as a retrofit) to a standard architecture.

[0138] Further advantages of the invention, relative to the solutions of the prior art, are the reduction of dispersions, the increase in combustion (the recycling of at least 50% of the combustion products of the burner obtained allows the use of regulations with reduced oxidants, taking advantage of the residual oxygen present in the recycled gas G) and the increase in the uniformity of the temperature inside the firing chamber 3, which, through the device 50 and the burner 1 according to the invention, determines the need to introduce smaller quantities of gas (particularly useful in the case of difficult to process fuels such as hydrogen) into the burner 1 in order to maintain a certain temperature.

[0139] In addition, the use of the multistage burner head 10 in combination with the injection element 32 makes it possible to reduce the temperature peaks in the flame mode, which are the main cause of the production of nitrogen oxides. Thus, the invention results in a reduction of nitrogen oxides (NOx) using natural gas, in particular below 50 ppm.

[0140] The use of the multi-stage burner head 10 in combination with the fuel injection element 18 allows the burner (operated in flameless mode with pure hydrogen (i.e., 100% hydrogen fuel)) to reduce its NOx emissions to below the NOx emissions produced by a conventional high-speed burner operated with natural gas. In this regard, the NOx emissions produced by the burner 1 operated with pure hydrogen in flameless mode (grey continuous curve FSL) can be Fig.12 As can be seen in the figure.

[0141] In the case of an optimum combination of the diameter of the narrowing 21 and the diameter of the introduction element 18, these NOx emissions are less than 40 ppm at a chamber temperature of 900° C. and 2-3% oxygen.

[0142] The increase of oxygen in the kiln chamber leads to a greater presence of nitrogen (N2), which causes a gradual increase in NOx emissions (dash-dot curve FSL'), especially at low burner capacities (8-10 kW), where the setting usually exceeds the oxidant air more (leading to a greater presence of N2).

[0143] In this particular case, NOx emissions are still significantly lower than common high velocity burner architectures operating in flame mode with methane gas as fuel.

[0144] In addition, it should be noted that increasing the diameter of the narrowing 21 and / or increasing the diameter of the fuel introduction element 18 leads to a lower flame pulse in the kiln chamber, thereby leading to a lower dilution of the flame in the presence of flue gases. This leads to a significant increase in NOx formation (dashed line FLS''). Even in this case, the NOx emissions are still much lower than the NOx emissions of a conventional high-speed burner operating in flame mode with methane gas as fuel.

[0145] In addition, the synergistic effect between the multi-stage burner head 10, the injection element 32 and the introduction element 18 allows a flame speed of about 200 m / s to be achieved and allows a uniformly diluted combustion in the flameless mode.

[0146] In addition, flameless combustion dilutes the temperature (i.e., reduces the peak value by increasing the median value) and increases the convection exchange coefficient with the ceramic product T. For this reason, the present invention can heat the material more than the conventional architecture at the same power without "eroding" the material with the temperature peak at the flame, and oxidizes the organic matter contained in the ceramic product T in a more uniform manner, thereby preventing the appearance of a darker color inside the segmented product. This also partially suppresses the risk of the ceramic product T exploding in the preheating zone of the kiln 2, for example, when a product with an excessive moisture content is fired.

[0147] Finally, thanks to the particular design of the introduction element, a mixture M* is produced downstream of the discharge element 11 that is free of a flame front, thereby reducing the problems associated with hydrogen flashback and detonation in the event of reformation of the flame front.

Claims

1. A burner (1) for firing ceramic products (T), the burner (1) being installable in an industrial kiln (2) comprising a firing chamber (3); The burner (1) comprises: A mixing body (5), the mixing body (5) comprising at least one conduit (6) for supplying a fuel (FL) and at least one conduit (7) for supplying an oxidant (OX); a spark device (8) for starting combustion; a flame detection device (9); a first tubular discharge element (11), the first tubular discharge element (11) being configured to be passed through by a fluid (F) flowing out of the mixing body (5) and having a first end (12) and a second end (14), at least a portion of the mixing body (5) being inserted into the first end (12), the second end (14) being opposite to the first end (12); The burner (1) is characterized in that it comprises an introduction element (18) which is configured to inject fuel (FL) downstream of the first tubular discharge element (11), in the region of the second end (14) or in a region protruding from the second end (14).

2. The burner (1) according to claim 1, wherein: The introduction element (18) comprises a first tubular duct (19) which extends at least from the first end (12) to the second end (14), in particular the first tubular duct (19) passes through the first tubular discharge element (11) from one side to the other.

3. The burner (1) according to claim 2, wherein: The first tubular duct (11) extends asymmetrically with respect to a longitudinal symmetry axis (AA) of the burner (1), in particular, wherein the first tubular duct (19) extends at least partially parallel to a wall (20), in particular an inner wall, of the first tubular discharge element (11).

4. The burner (1) according to claim 2 or 3, wherein: The first tubular conduit (19) comprises at least a first straight portion (22) and a second straight portion (23) connected to each other via a curved portion (24).

5. The burner (1) according to claim 4, wherein: The curved portion (24) is arranged close to the second opening (15), namely at a distance less than or equal to 20 cm from the second opening (15).

6. The burner (1) according to any one of claims 2 to 5, wherein: The inner diameter of the first tubular channel (19) is less than or equal to 10 mm, in particular less than or equal to 7 mm.

7. The burner (1) according to any one of the preceding claims, wherein: The introduction element (18) extends inside the first tubular discharge element (11).

8. The burner (1) according to any one of the preceding claims, wherein: The introduction element (18) comprises an end (25) which protrudes from the second opening (15) beyond the first tubular discharge duct (11) by a distance greater than or equal to 5 mm, in particular greater than or equal to 10 mm.

9. A burner (1) according to any one of the preceding claims, comprising a first supply system (26) for the fuel (FL) and a second supply system (27) for the fuel (FL), the first supply system (26) for the fuel (FL) being connected to the supply pipe (6) for the fuel (FL), the second supply system (27) for the fuel (FL) being separate from the first supply system (26) for the fuel (FL) and being connected to the introduction element (18); in particular, the first supply system (26) for the fuel (FL) and the second supply system (27) for the fuel (FL) are capable of selectively and / or independently operating; in particular, the first supply system (26) for the fuel (FL) and the second supply system (27) for the fuel (FL) are both connected to different pipes (6, 6') obtained on the breech (29) of the mixing body (5).

10. The burner (1) according to any one of the preceding claims, wherein: The mixing body (5) comprises a fuel distribution system (FPS) for the fuel (FL) and an oxidant distribution system (OPS) for the oxidant (OX), wherein the fuel distribution system is configured to divide the fuel (FL) into a plurality of first parts (FL', FL", FL"'), and the oxidant distribution system is configured to divide the oxidant (OX) into a plurality of second parts (OX', OX", OX"'), wherein the plurality of second parts are conveyed to be mixed with the first part in at least two different stages.

11. The burner (1) according to claim 10, wherein: The oxidant distribution system (OPS) for the oxidant (OX) comprises a combustion head (10) arranged at least partially inside the first tubular discharge element (11) and comprising one or more combustion chambers (30, 31), each of which is configured to contain a different stage (M', M") of flame combustion; And wherein the fuel distribution system (FPS) for the fuel (FL) comprises an injection element (32), which is configured to inject at least a maximum portion (FL'") of the fuel (FL) downstream of the combustion head (10) towards the second end (14); in particular, the first tubular discharge element (11) is configured to contain the primary stage (F') of the flame combustion.

12. The burner (1) according to claim 11, wherein: The injection element (32) comprises a second tubular duct (33) which passes through the one or more combustion chambers (30, 31) from one side to the other; in particular, the first tubular duct (19) and the second tubular duct (33) have a substantially constant, in particular circular, cross section.

13. The burner (1) according to any one of the preceding claims, further comprising: at least one second tubular discharge element (38), the at least one second tubular discharge element (38) extending from the second end (14) toward the opposite side relative to the first end (12); and a suction element (39), the suction element (39) being configured to guide at least a portion of the gas (G) present outside the burner (1) into the second tubular discharge element (38).

14. An industrial device (50) for firing a ceramic product (T), comprising: A tunnel kiln (2), the tunnel kiln (2) having at least one side wall (27), the side wall (27) at least partially defining a firing chamber (3) and having an inner surface (51) inside the firing chamber (3) and an outer surface (52) outside the firing chamber (3); a transport system (4), the transport system (4) being configured to transport a plurality of ceramic products (T) along a transport path (P) in the firing chamber (3); The device (50) is characterized in that it comprises at least one burner (1) according to any one of claims 1 to 13; the industrial device (50) comprises at least one hydrogen supply system (S), which is configured to selectively inject hydrogen or a mixture containing hydrogen into the fuel supply pipeline (6) or the introduction element (18).

15. The device (50) according to claim 14, comprising at least one electronic control unit (53) configured to control the burner (1) so as to switch from an ignition configuration with flame to an ignition configuration without flame.

16. The device (50) according to claim 14 or 15, wherein: The electronic control unit (53) is configured as follows: Once a predetermined temperature is reached in the firing chamber (3), the flame is extinguished by reducing or stopping the supply of the fuel (FL) in the fuel supply conduit (6) and, if necessary, the oxidant (OX) in the oxidant supply conduit (7), respectively; Fuel (FL) is introduced into the introduction element (18) and, if necessary, the supply of oxidant (OX) in the oxidant supply conduit (7) is restored, thereby allowing the burner (1) to fire in flameless mode.

17. A method for firing a ceramic product (T) transported in a tunnel kiln (2), comprising the following steps: supplying a burner (1), in particular a burner (1) according to any one of claims 1 to 13, with a fuel (FL), said fuel (FL) comprising a proportion of hydrogen of at least more than 20%, in particular more than 50%, more particularly more than 70%, more particularly all hydrogen; Simultaneously supplying an oxidant (OX) to the burner (1) and igniting a flame at least partially in the burner (1) and in the firing chamber (3) of the tunnel kiln (2); Controlling the flame by feedback until a predetermined temperature is reached in the firing chamber (3); The method is characterized in that once the firing chamber (3) reaches the predetermined temperature, the method further comprises the following steps: extinguishing the flame by reducing or stopping the supply of the fuel (FL) in the fuel supply conduit (6) and in particular the supply of the oxidant (OX) in the oxidant supply conduit (7); and The introduction of fuel (FL) into the introduction element (18) in particular restores the supply of the oxidant (OX), thereby directly generating a mixture (M*) in the firing chamber (3), said mixture (M*) determining the flameless combustion for firing the ceramic article (T).

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