Ring burner for the manufacture of mineral fibers

Abstract

The present invention relates to an annular burner for the manufacture of mineral fibers, comprising a combustion chamber and a nozzle, the combustion chamber and the nozzle having rotational symmetry about a principal axis, the nozzle fluidly connecting the combustion chamber to the exterior of the burner, the burner comprising injectors, the number of injectors being strictly greater than five, each injector being adapted to inject a mixture of fuel and oxidizer into the combustion chamber, the injectors being distributed around the combustion chamber, the combustion chamber having a first volume, the burner being characterized in that the ratio between the first volume and the number of injectors is between 725 cm³ and 900 cm³. FIG. 1

Description

Title of the invention: Ring burner for the manufacture of mineral fibers. Field of the invention

[0001] The present invention relates to an annular burner for the manufacture of mineral fibers by internal centrifugation, as well as an installation comprising such a burner. State of the art

[0002] It is known to manufacture mineral wool by an internal centrifugation process. Document EP4274813 describes, for example, an installation comprising an annular burner for manufacturing glass fibers by internal centrifugation. During the centrifugation of a shaft connected to a basket and a plate, molten mineral material is projected radially about the shaft's main axis of centrifugation onto a strip of a plate equipped with orifices. The molten mineral material passes through the orifices so as to form filaments. The annular burner comprises a combustion chamber and a nozzle opening onto the orifices. Thus, the gases produced by combustion in the combustion chamber are expelled from the combustion chamber onto the filaments, imparting momentum to the filaments, which stretches them to form fibers.Furthermore, the gases produced by combustion heat the filaments as they exit the orifices, contributing to their stretching. The fuel and oxidizer used are methane and air, respectively. A flame, driven by the combustion of methane and oxygen from the air, is maintained in the combustion chamber during fiber production.

[0003] However, known combustion chambers are adapted for the combustion of methane. This combustion produces carbon dioxide. Description of the invention

[0004] An object of the invention is to provide an annular burner that reduces the amount of carbon dioxide emitted during combustion in the burner.

[0005] This objective is achieved, at least partially, within the framework of the present invention by means of an annular burner for the manufacture of mineral fibers, comprising a combustion chamber and a nozzle, the combustion chamber and the nozzle having rotational symmetry with respect to a principal axis, the nozzle fluidly connecting the combustion chamber to the outside of the burner, the burner comprising injectors, the number of injectors being strictly greater than five, each injector being adapted to inject a mixture of fuel and oxidizer into the combustion chamber, the injectors being distributed around the combustion chamber, the combustion chamber having a first volume, the ratio between the first volume and the number of injectors being between 725 cm3 and 900 cm3.

[0006] The present invention is advantageously complemented by the following features, taken individually or in any of their technically possible combinations:

[0007] - the first volume is formed by a revolution of a section around the main axis, a cross-sectional area being between 130 cm2 and 155 cm2, preferably between 135 cm2 and 150 cm2,

[0008] - the number of injectors is between 5 and 35, preferably between 20 and 30,

[0009] - the first volume is between 15,000 cm3 and 25,000 cm3, preferably between 18,000 cm3 and 20,000 cm3,

[0010] - each injector is configured to mix the oxidizer and the fuel in the burner,

[0011] - each injector includes an angular deflector configured to generate a swirling flow of oxidizer and / or fuel in the injector,

[0012] - each injector includes a first fluidic inlet adapted for a fuel containing dihydrogen

[0013] - the combustion chamber comprises a wall distal to the main axis, The injectors are distributed around the distal wall and Each injector is adapted to inject the fuel and oxidizer mixture into the combustion chamber through a second fluidic inlet formed in the distal wall,

[0014] - the distal wall has a first height h measured between two ends of the distal wall relative to the main axis, each second fluidic inlet being arranged at a distance between one-third of the first height and two-thirds of the first height from one end of the distal wall relative to the main axis, and preferably arranged at a distance between 2 / 5 of the first height and 3 / 5 of the first height from one end of the distal wall relative to the main axis,

[0015] - each injector is arranged to allow injection of the fuel and the oxidizer in the combustion chamber along a mean direction orthogonal to the distal wall,

[0016] - the combustion chamber comprises a wall distal to the main axis, a proximal wall relative to the main axis, and a combustion product outlet wall defined between the distal wall and the proximal wall, the nozzle ends being surrounded by the outlet wall in a distal direction and in a proximal direction relative to the main axis,

[0017] - the burner comprises: - a flame detector comprising a sensor configured to detect light radiation and / or ionizing radiation emitted towards the sensor, - a passage comprising a straight opening formed in one of the walls of the combustion chamber,

[0018] - the passage opens into the combustion chamber through a part of the wall proximal located between the injector and the outlet wall and / or by the outlet wall,

[0019] - the burner includes a mirror arranged outside the combustion chamber at the outlet of the opening, the mirror is arranged so as to optically align a flame generated in the combustion chamber and the detector.

[0020] Another aspect of the invention is an installation for the production of mineral fibers, the installation comprising: - an annular burner according to an embodiment of the invention, - a fiber-forming plate having orifices, adapted to receive a molten mineral material, and adapted to form filaments of the mineral material from the orifices by centrifugation of the plate.

[0021] Advantageously, the burner comprises: - the first fluidic inlet, the first fluidic inlet being configured to receive a first fluid at a first flow rate, the first fluid comprising a fuel, the fuel comprising dihydrogen, a volume fraction of dihydrogen in the first fluid being greater than 0.05, the first fluidic inlet being fluidly connected to the combustion chamber by the injectors, and - a third fluidic inlet configured to receive a second fluid at a second flow rate, the second fluid having a volume fraction of oxygen greater than 0.10, the third fluidic inlet being fluidly connected to the combustion chamber by the injectors, the installation comprising a control unit configured to control the first flow rate of the first fluid and the second flow rate of the second fluid so that the pressure PB in the combustion chamber is between 1961 Pa (200 mm CE) and 7845 Pa (800 mm CE),particularly between 4413 Pa (450 mm CE) and 7355 Pa (750 mm CE) and preferably between 5394 Pa (550 mm CE) and 6374 Pa (650 mm). Description of the figures

[0022] Other features, objectives and advantages of the invention will become apparent from the following description, which is purely illustrative and not limiting, and which should be read in conjunction with the accompanying drawings on which:

[0023] [Fig-1] - [Fig.1] schematically illustrates a burner according to one embodiment of the invention,

[0024] [Fig.2] - [Fig.2] schematically illustrates part of an installation according to one embodiment of the invention,

[0025] [Fig.3] - [Fig.3] schematically illustrates a burner comprising a flame detector according to an embodiment of the invention,

[0026] [Fig.4] - [Fig.4] schematically illustrates a flame detector according to one embodiment of the invention,

[0027] [Fig.5] - [Fig.5] illustrates a simulation of gas flow in the combustion chamber during combustion,

[0028] [Fig.6] - the [Fig.6] illustrates the variation of a mass flux of momentum at the outlet of a burner with a total fuel flow rate.

[0029] Throughout the figures, similar elements bear identical reference numerals. Definitions

[0030] The term “richness q>” of a combustion reaction means a ratio between, on the one hand, the ratio between the quantity of fuel and the quantity of air used in a combustion reaction, and on the other hand, the ratio between the quantity of fuel and the quantity of air used in a reaction of the same combustion under stoichiometric conditions. Detailed description of the invention

[0031] General description of burner 1 and installation 18

[0032] With reference to [Fig. 1], one aspect of the invention is an annular burner 1 for the manufacture of mineral fibers 2. The burner 1 comprises a combustion chamber 3 and a nozzle 4. The combustion chamber 3 and the nozzle 4 have rotational symmetry about a principal axis 5. The principal axis 5 coincides with the axis of rotation of the shaft when the burner 1 is installed in a mineral fiber manufacturing plant 18. The nozzle 4 fluidly connects the combustion chamber 3 to the outside of the burner 1. The burner 1 includes injectors 6. Each injector 6 is adapted to inject a mixture of fuel and oxidizer into the combustion chamber 3.

[0033] The number of injectors 6 is strictly greater than five. The number of injectors 6 can be between 5 and 35, preferably between 20 and 30. The injectors 6 are distributed around the combustion chamber 3. The combustion chamber 3 has a first volume. The ratio between the first volume and the number The injector volume 6 is between 725 cm³ and 900 cm³, and preferably between 750 cm³ and 850 cm³. The inventors discovered that a ratio chosen within the aforementioned range allows the use of a flame produced from a fuel containing dihydrogen for the manufacture of mineral fibers 2 with a flow rate between 3 L / min and 24 L / min, particularly between 6 L / min and 20 L / min. Indeed, the manufacture of such fibers requires a stretching power that is achieved with a dihydrogen flame produced in a combustion chamber with such a ratio. Moreover, for this power, the ratio must be limited. In fact, on the one hand, when the ratio is less than 900 cm³, the homogeneity of the combustion chamber volume in which a flame is likely to be generated is increased. This helps to avoid incomplete combustion, because the amount of injected gas that does not participate in combustion is minimized.Furthermore, for a ratio greater than 725 cm³, interactions between the different flames produced by the different injectors, or between a flame and a wall of the combustion chamber 3, are avoided. This prevents combustion instability, which reduces the homogeneity of the combustion chamber volume in which a flame is likely to be generated. Finally, by avoiding interactions between a flame and a wall of the combustion chamber 3, energy losses through heat transfer in the material forming the combustion chamber are minimized.

[0034] With reference to [Fig. 1], [Fig. 2], and [Fig. 3], the first volume is formed by rotating a section around the principal axis 5. The area of ​​the section can be between 130 cm² and 155 cm², preferably between 135 cm² and 150 cm². Thus, adjusting the combustion chamber geometry for use with a fuel containing dihydrogen can be implemented independently of any variation in the maximum diameter of the combustion chamber in a plane perpendicular to the axis of rotation. The first volume can be between 15,000 cm³ and 25,000 cm³, and preferably between 18,000 cm³ and 20,000 cm³.

[0035] With reference to [Fig. 2], another aspect of the invention is an installation 18 for the production of mineral fibers 2. The installation 18 comprises an annular burner 1 according to an embodiment of the invention. The installation 18 also comprises a fiber-forming plate 19 having orifices 20. The plate 19 is adapted to receive molten mineral material and adapted to form filaments 21 of the mineral material from the orifices 20 by centrifugation of the plate 19. Thus, due to the presence of the burner 1 according to an embodiment of the invention, the mineral fibers produced are more homogeneous and are produced while reducing the amount of carbon dioxide emitted for a predetermined quantity of fibers produced. Injector 6

[0036] Each injector 6 can be configured to mix the oxidizer and the fuel in the burner 1. Thus, it is possible not to mix the fuel and the oxidizer prior to their introduction into the burner, which avoids the risk of combustion spreading outside the burner 3, while allowing a mixture of the fuel and the oxidizer to be injected directly into the burner 3, which increases combustion safety when using dihydrogen as fuel while ensuring combustion stability.

[0037] An injector 6 may include an angular deflector configured to generate a vortex flow of oxidizer and / or fuel within the injector 6. The injector 6 may include a mixing line. The angular deflector enables a flow in which the fuel and oxidizer flow along at least a portion of the mixing line in the same principal flow direction, and such that the oxidizer rotates relative to the fuel about an axis oriented along the principal flow direction.

[0038] The angular deflector can be adapted to generate a vortex flow of the fuel and oxidizer in the mixing line. The angular deflector can have a vortex number S that satisfies the equation S = 2 / 3 tan(U), where U is the angular deflection angle of the fuel and / or oxidizer flow after passing through the injector 6. The vortex number S can be between 0.10 and 2.00, preferably between 0.25 and 1.70, in particular between 0.35 and 1.40, and preferably between 0.45 and 1.10, again preferably between 0.50 and 0.90, and again preferably between 0.65 and 0.70. The intensity of the rotary motion of the flow is characterized by the value of the swirl number S at the outlet of injector 6. The swirl number S defines the ratio between the tangential and axial momentum fluxes. It can be defined by the following equation:

[0039] [Math.9] L UWr2dr RjnU~rdr where U and W are respectively the axial and tangential components of the average flow velocity, r a distance defining a radial coordinate, and R e is the radius of the mixing pipe. This vortex number S is approximated by the formula S = 2 / 3 tan ip.

[0040] Increasing the number of vortices S allows the flame height 15 to be reduced and the flame opening 15 to be increased. A wide flame opening allows limiting the number of injectors for burner 1, while allowing homogeneous heating in the combustion chamber.

[0041] The angular deflection element 15 can be formed by a ring arranged coaxially with the main flow direction. The ring can be removable. The ring can include a conduit adapted to introduce a swirling flow of fuel and / or oxidizer into the mixing conduit with an angular deflection angle rp, the value of which can be between 10° and 80°, in particular between 20° and 70°, more preferably between 30° and 60°, and more preferably between 40° and 50°. Thus, it is possible to maximize the mixing of the fuel and oxidizer before their introduction into the combustion chamber 3. This helps to stabilize combustion in the combustion chamber. Several deflectors can be arranged in the mixing conduit.

[0042] The injector 6 may include a first fluidic inlet adapted for a fuel containing dihydrogen. The first fluidic inlet may be formed by one or more hydrogen-impermeable materials. Combustion chamber geometry and shape

[0043] The combustion chamber 3 is formed by several distinct walls. Typically, the combustion chamber may include a distal wall 7, a proximal wall 10, an upper wall 25, and an outlet wall 11. The distal wall 7 may be of revolution about the main axis 5. The distal wall 7 may be cylindrical or frustoconical. The proximal wall 10 may be of revolution about the main axis 5. The proximal wall 10 may be cylindrical or frustoconical. The upper wall 25 connects one end of the proximal wall 10 and one end of the distal wall 7. The upper wall 25 may be planar. It may be of revolution about the main axis 5 and orthogonal to the main axis 5. The outlet wall 11 connects another end of the proximal wall 10 and another end of the distal wall 7. The outlet wall 11 may be planar. It can be of revolution with respect to the principal axis 5 and orthogonal to the principal axis 5.The outlet wall 11 may comprise two parts, one proximal and the other distal, the two parts being separated by one end of the nozzle 4.

[0044] The injectors 6 can be distributed around the distal wall 7. Each injector 6 can be adapted to inject the fuel and oxidizer mixture into the combustion chamber 3 through a second fluidic inlet 8 formed in the distal wall 7. Thus, the volume of the combustion chamber that can be occupied by a flame 15 during combustion is maximized while minimizing the diameter of the burner 1.

[0045] The distal wall 7 may have a first height h measured between two ends of the distal wall 7 with respect to the main axis 5. The height h may to be measured between the outlet wall 11 and between the upper wall 25. Each second fluidic inlet 8 can be arranged at a distance of between one-third of the first height h and two-thirds of the first height h from one end of the distal wall 7 relative to the main axis 5, and preferably arranged at a distance of between 2 / 5 of the first height h and 3 / 5 of the first height h from one end of the distal wall 7 relative to the main axis 5. Thus, as illustrated by [Fig. 5], a flame 15 generated from an injector 6 in the combustion chamber 3 can be stabilized both by gas recirculation between the flame 15 and the upper wall 25 and by gas recirculation between the flame 15 and the outlet wall 11. Both recirculations induce stresses of the same order of magnitude on the flame 15, which stabilizes it.

[0046] With reference to [Fig. 5], each injector 6 can be arranged to allow the injection of fuel and oxidizer into the combustion chamber 3 along a mean direction 9 orthogonal to the distal wall 7. Thus, it is possible to maximize the angle formed by the flame 15 at the outlet of the second fluidic inlet 8 without the flame 5 coming into contact with either of the walls, for example the outlet wall 11 and / or the upper wall 25. Such contact would lead to a decrease in the efficiency of the burner 1, due to increased heat transfer at the point of contact between the wall and the flame 15.

[0047] With reference to [Fig. 1], [Fig. 2], and [Fig. 3], the combustion chamber 3 includes an outlet wall 11 for the combustion products. The outlet wall 11 is defined between the distal wall 7 and the proximal wall 10. The ends of the nozzle 4 can be surrounded by the outlet wall 11 in a distal direction 12 and in a proximal direction 13 with respect to the main axis 5. This prevents the formation of a dead zone in the recirculation of the gases ejected from the combustion chamber within the nozzle 4. This allows for the homogenization of the temperature and / or momentum of the gases expelled from the nozzle 4 over time and also in space as a revolution around the main axis 5. Optical flame detection 15

[0048] Flame detection inside a burner is important for the safety of the installation. A flame detector makes it possible to detect the presence or absence of a flame 15, which allows for an immediate response in the event of a failure or malfunction of the flame 15.

[0049] With reference to [Fig. 3], the burner 1 may include a flame detector 14 15. The detector 14 includes a sensor configured to detect light radiation and / or ionizing radiation emitted in the direction of the sensor. The burner 1 may include a passage 16. The passage may include an opening 17 formed in one of the walls of the combustion chamber 3.

[0050] The first fluidic inlet can be adapted for a fuel containing dihydrogen. The detector 14 can then include an optical sensor adapted to measure the intensity of ultraviolet light rays. Thus, a flame 15 formed by the combustion of dihydrogen can be detected. The sensor can be a photodiode or a phototube.

[0051] With reference to [Fig.3], the passage 16 can be arranged so that light radiation and / or ionizing radiation emitted by the flame 15 can pass through the passage 16.

[0052] The passage 16 can open into the combustion chamber 3 through a part of the proximal wall located between the injector 6 and the outlet wall 11 and / or through the outlet wall 11. Thus, it is possible to minimize the risk of fuel leakage into the combustion chamber 3, which is important when using dihydrogen as fuel.

[0053] With reference to [Fig. 4], the burner 1 may include a mirror 24. The mirror 24 may be arranged outside the combustion chamber at the outlet of the passage 16. The mirror 24 may be arranged so as to optically align a flame generated in the combustion chamber 3 with the detector 14. Thus, it is possible to reduce the space occupied by the burner 1 in a radial direction. This may prove necessary when using dihydrogen as fuel, particularly when the burner 1 is surrounded by an oxidizer and / or fuel distribution ring. Use of dihydrogen as a fuel

[0054] The first fluid inlet can be configured to receive a first fluid at a first flow rate. The first fluid may comprise a fuel, the fuel comprising dihydrogen, with a volume fraction of dihydrogen in the first fluid greater than 0.05, in particular greater than 0.15, in particular greater than 0.2, and preferably greater than 0.5. The fuel may also comprise at least one organic compound. The organic compound(s) may be selected from methane, biogas, propane, and liquefied petroleum gas. The fuel may comprise a mixture of the organic compound(s) and dihydrogen, and preferably a mixture of methane and dihydrogen.

[0055] The first fluidic inlet is fluidically connected to the combustion chamber 3 by the injectors 6.

[0056] The burner 1 may also include a third fluid inlet. The third fluid inlet is configured to receive a second fluid at a second flow rate, the second fluid having an oxygen volume fraction greater than 0.10. The second fluid 10 can be air. The third fluid inlet is fluidically connected to the combustion chamber 3 by the injectors 6.

[0057] The fuel may comprise methane and dihydrogen. A stoichiometric combustion reaction of a mixture comprising methane and dihydrogen with air can be modeled by the following equation:

[0058] [Math.l] (CH4+aH2) + (#2+3.76 N2) ^C#2 + (2 + «X#+3.76(^ )N2 in which a is equal to the number of moles of dihydrogen.

[0059] A combustion reaction in excess air of a mixture comprising methane and dihydrogen with air can be modeled by the following equation:

[0060] [Math.2] (CH4+aH2) + )^(O2 + 3.76A2) ^CO2 + (2 + a')H,O+ 3.76 / (^ )A'2 + (^ ) (L1)O2 where X is the air ratio which is defined by the following equation:

[0061] [Math.3] $~AFRst where q is the richness, AFR is the dosage, also called in English air fuel ratio, and AFR sl is the ideal dosage, also called stoichiometric dosage or in English sto i chiometric air fuel ratio.

[0062] The AFR assay can be defined by the following equation:

[0063] [Math.4] P AM * #,0 Mftial Wir AF Jt______________ PcufQcH^HfQH, 2^(McH*Qcg+MH*Q^

[0064] where rilA-r is the mass flow rate of air introduced into the combustion chamber, rÙcj / 4 is the mass flow rate of methane introduced into the combustion chamber, rfl#, is the mass flow rate of dihydrogen introduced into the combustion chamber, P^r is the density of the air when it is introduced into the combustion chamber, Q..is the air flow rate upon its introduction into the combustion chamber, Pcha is the density of methane upon its introduction into the combustion chamber, QCH is the flow rate of methane upon its introduction into the combustion chamber, Ph2 is the density of dihydrogen upon its introduction into the combustion chamber, QH is the flow rate of dihydrogen upon its introduction into the combustion chamber, Pimtiai is the air pressure at the inlet of combustion chamber 4, R is the universal ideal gas constant, is the temperature at the inlet of combustion chamber 4, is the molar mass of air, Mcha is the molar mass of methane and Al h is the molar mass of dihydrogen.

[0065] The ideal AFR st titration can be defined by the following equation:

[0066] [Math.5] (^)(32+3.76^8) ^st— — (16+2«)

[0067] where nO2 is the quantity of dioxygen introduced into the combustion chamber 3, nN2 is the quantity of nitrogen introduced into the combustion chamber 3, ncn* is the quantity of methane introduced into the combustion chamber 3 and nH2 is the quantity of dihydrogen introduced into the combustion chamber 3.

[0068] Thus, the general combustion equation including methane and dihydrogen as fuels can be defined by the following formula:

[0069] [Math.6] (nCH4C^ + + 3-761V2) nCHiC02 + (2nc^ + a)H20 + 3.762 N2 + (À _ 1)Û2

[0070] Thus, to know the composition of the combustion products, it is necessary to know three parameters: the quantity of methane introduced into the combustion chamber 3, the quantity of dihydrogen introduced into the combustion chamber 3 and X. In addition, it is possible to calculate an adiabatic flame temperature and a nozzle lip temperature 4 (at the outlet of the burner 1) from the previous equations by calculating the molar enthalpies of the products and reactants of the previous equation.

[0071] The filaments 21 are stretched to form the mineral fibers 2 by applying an aerodynamic force driven by the compounds expelled from the combustion chamber 3 to the filaments 21 during combustion. The acceleration of the stretching caused by this aerodynamic force controls the diameter of the mineral fibers 2.

[0072] The stretching of the filaments 21 is locally controlled by a surface density jp of momentum flux at the lips 26 of the burner 1. The surface density jp is defined by the following equation:

[0073] [Math.7] Mb = dS

[0074] where MB is a mass flux of momentum and where S is a cross-section through which the compounds contained in the combustion chamber 3 are expelled by the nozzle outside the burner 1 following combustion. The nozzle 4 connects the combustion chamber 3 to the outside of the burner 1. One end of the nozzle 4 forms two lips 26 defining a cross-section through which the compounds The contents of combustion chamber 3 are expelled from burner 1 following combustion. The cross-section S is defined by the burner lips 26.

[0075] With reference to [Fig. 6], the mass flux MB of momentum decreases for an increasing proportion of dihydrogen during combustion determined by a constant air-fuel ratio q. Curve (a) illustrates the mass flux MB as a function of the total fuel flow rate, the fuel consisting solely of methane, for an air-fuel ratio q equal to 0.69. Curve (b) illustrates the mass flux MB as a function of the total fuel flow rate, the fuel consisting of 90% methane and 10% dihydrogen, for an air-fuel ratio <p égale à 0,69. la courbe (c) illustre le flux massique m b en fonction du débit total de combustible, combustible comprenant 80 % méthane et 20 dihydrogène, pour une richesse q>equal to 0.69. Curve (d) illustrates the mass flow MB as a function of the total fuel flow rate, the fuel comprising 70% methane and 30% dihydrogen, for a richness q > equal to 0.69. Curve (e) illustrates the mass flow MB as a function of the total fuel flow rate, the fuel comprising only dihydrogen, for a richness q > equal to 0.69.

[0076] The mass flux MB of momentum is defined by the following equation:

[0077] [Math. 8] m b =q b .u b =p b s

[0078] where QB is the mass flow rate of compounds evacuated from burner 1, UB is the velocity of compounds evacuated from burner 1 and PB is the pressure in combustion chamber 3.

[0079] Thus, the pressure PB in the combustion chamber 4 allows control of the stretching of the filaments 21 so that the formed mineral fibers 2 exhibit thermal and / or acoustic insulation characteristics. Preferably, the pressure PB in the combustion chamber 3 is between 1961 Pa (200 mm CE) and 7845 Pa (800 mm CE), in particular between 4413 Pa (450 mm CE) and 7355 Pa (750 mm CE), and preferably between 5394 Pa (550 mm CE) and 6374 Pa (650 mm CE). Therefore, it is possible to manufacture mineral fibers 2 with a flow rate between 3 L / min and 24 L / min, in particular between 6 L / min and 20 L / min, using at least some of dihydrogen as fuel. The rotation speed of the plate can exceed 2000 rpm. The fiber extraction through the plate may be less than 1 kg per day per plate opening, and in particular less than 0.6 kg per day per plate opening.

[0080] The pressure PB in the combustion chamber 3 can be determined by the geometry of the combustion chamber 3, the geometry of the nozzle 4, the first flow rate, the second flow rate, a composition of the first fluid and a composition of the second The combustion reaction can be maintained in combustion chamber 3 by introducing a mass flow rate of methane at 9.96 kg / h, a mass flow rate of dihydrogen at 0.75 kg / h (the volume fraction of dihydrogen in the first fuel being 0.07), and a mass flow rate of the second fluid, consisting of air, at 285 kg / h. The combustion reaction described above allows a mass flux MB of 18.9 kg·m / s² to be applied to the platform while maintaining a pressure PB in combustion chamber 3 of 6002 Pa (612 mm CE).

[0081] The installation 18 may include a control unit. The control unit may be configured to control the first flow rate of the first fluid 22 and the second flow rate of the second fluid 23 such that the pressure PB in the combustion chamber is between 1961 Pa (200 mm CE) and 7845 Pa (800 mm CE), in particular between 4413 Pa (450 mm CE) and 7355 Pa (750 mm CE), and preferably between 5394 Pa (550 mm CE) and 6374 Pa (650 mm CE). Thus, the installation makes it possible to produce mineral fibers 2 with a micron density between 3 L / min and 24 L / min, in particular between 6 L / min and 20 L / min, using at least some of dihydrogen as fuel. The pressure PB may be calculated according to a predetermined model from the first and second flow rates. The pressure PB may also be measured by a pressure sensor.The pressure sensor can be chosen from a pitot tube and a sensor arranged on the burner lips configured to emit a signal representative of the pressure in the combustion chamber.

Claims

Demands

1. Annular burner (1) for the manufacture of mineral fibers (2), comprising a combustion chamber (3) and a nozzle (4), the combustion chamber (3) and the nozzle (4) having rotational symmetry about a principal axis (5), the nozzle (4) fluidly connecting the combustion chamber (3) to the outside of the burner (1), the burner (1) comprising injectors (6), the number of injectors (6) being strictly greater than five, each injector (6) being adapted to inject a mixture of fuel and oxidizer into the combustion chamber (3), the injectors (6) being distributed around the combustion chamber (3), the combustion chamber (3) having a first volume, the burner (1) being characterized in that the ratio between the first volume and the number of injectors (6) is between 725 cm3 and 900 cm3.

2. Burner (1) according to claim 1, wherein the first volume is formed by a revolution of a section around the principal axis (5), an area of ​​the section being between 130 cm2 and 155 cm2, preferably between 135 cm2 and 150 cm2.

3. Burner (1) according to claim 1 or 2, wherein the number of injectors (6) is between 5 and 35, preferably between 20 and 30.

4. Burner (1) according to any one of claims 1 to 3, wherein the first volume is between 15,000 cm3 and 25,000 cm3, preferably between 18,000 cm3 and 20,000 cm3.

5. Burner (1) according to any one of claims 1 to 4, wherein each injector (6) is configured to mix the oxidizer and fuel in the burner (1).

6. Burner (1) according to any one of claims 1 to 5, wherein each injector (6) comprises an angular deflector configured to generate a swirling flow of oxidizer and / or fuel in the injector (6).

7. Burner (1) according to any one of claims 5 to 6, wherein each injector (6) comprises a first fluidic inlet adapted for a fuel comprising dihydrogen.

8. Burner (1) according to any one of claims 1 to 7, wherein the combustion chamber (3) comprises a distal wall (7) relative to the main axis (5), the injectors (6) being distributed around the distal wall (7) and each injector (6) being adapted to inject the fuel and oxidizer mixture into the combustion chamber (3) through a second fluidic inlet (8) formed in the distal wall (7).

9. Burner (1) according to the preceding claim, wherein the distal wall (7) has a first height h measured between two ends of the distal wall (7) with respect to the main axis (5), each second fluidic inlet (8) being arranged at a distance between one third of the first height and two thirds of the first height from one end of the distal wall (7) with respect to the main axis (5), and preferably arranged at a distance between 2 / 5 of the first height and 3 / 5 of the first height from one end of the distal wall (7) with respect to the main axis (5).

10. Burner (1) according to any one of claims 1 to 9, wherein each injector (6) is arranged to permit injection of fuel and oxidizer into the combustion chamber (3) in a mean direction (9) orthogonal to the distal wall (7).

11. Burner (1) according to any one of claims 1 to 10, wherein the combustion chamber (3) comprises a distal wall (7) with respect to the main axis (5), a proximal wall (10) with respect to the main axis (5), and a combustion product outlet wall (11) defined between the distal wall (7) and the proximal wall (10), the ends of the nozzle (4) being surrounded by the outlet wall (11) in a distal direction (12) and in a proximal direction (13) with respect to the main axis (5).

12. Burner (1) according to any one of claims 1 to 11, comprising: - a flame detector (14) (15) comprising a sensor configured to detect light radiation and / or ionizing radiation emitted towards the sensor, - a passage (16) comprising an opening (17) formed in one of the walls of the combustion chamber (3).

13. Burner (1) according to the preceding claim, wherein the passage 16 opens into the combustion chamber 3 through a portion of the proximal wall located between injector 6 and outlet wall 11 and / or by outlet wall 11.

14. Burner (1) according to any one of claims 12 to 13, comprising a mirror (24) arranged outside the combustion chamber at the outlet of the passage (16), the mirror being arranged so as to optically align a flame generated in the combustion chamber (3) and the detector (14).

15. Installation (18) for the production of mineral fibers (2) comprising: - an annular burner (1) according to any one of claims 1 to 14, - a fiber-forming plate (19) having orifices (20), adapted to receive a molten mineral material, and adapted to form filaments (21) of the mineral material from the orifices (20) by centrifugation of the plate (19).

16. Installation (18) according to the preceding claim, wherein the burner (1) comprises: - the first fluidic inlet, the first fluidic inlet being configured to receive a first fluid (22) at a first flow rate, the first fluid (22) comprising a fuel, the fuel comprising dihydrogen, a volume fraction of dihydrogen in the first fluid (22) being greater than 0.05, the first fluidic inlet being fluidically connected to the combustion chamber (3) by the injectors (6), and - a third fluidic inlet configured to receive a second fluid (23) at a second flow rate, the second fluid (23) having a volume fraction of oxygen greater than 0.10, the third fluidic inlet being fluidly connected to the combustion chamber (3) by the injectors (6),the installation (18) comprising a control unit configured to control the first flow rate of the first fluid and the second flow rate of the second fluid so that the pressure PB in the combustion chamber is between 1961 Pa (200 mm CE) and 7845 Pa (800 mm CE).

Images