Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D11/00—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space
  • F23D11/10—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space the spraying being induced by a gaseous medium, e.g. water vapour
  • F23D11/106—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space the spraying being induced by a gaseous medium, e.g. water vapour medium and fuel meeting at the burner outlet
  • F23D11/107—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space the spraying being induced by a gaseous medium, e.g. water vapour medium and fuel meeting at the burner outlet at least one of both being subjected to a swirling motion
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D2900/00—Special features of, or arrangements for burners using fluid fuels or solid fuels suspended in a carrier gas
  • F23D2900/11101—Pulverising gas flow impinging on fuel from pre-filming surface, e.g. lip atomizers

Definitions

• the invention relates to a method and a combustion device in which the fuel supply is provided by at least one injector.
• the invention will be more particularly described for use in the melting of glass in glassmaking furnaces, in particular furnaces for the manufacture of float-type flat glass or ovens for the manufacture of hollow packaging glass, for example ovens. operating in inversion of the type of those using regenerators (energy recovery) but it is not limited to such applications.
• NOx has a detrimental effect on both human beings and the environment.
• NO 2 is an irritant gas at the source of respiratory diseases.
• they can gradually form acid rain.
• NOx are responsible for the formation of so-called tropospheric ozone whose increase in concentration at low altitude becomes harmful to the environment. being human, especially in times of high heat.
• NOx grows exponentially, excess air since the NOx concentration depends on the square root of that of oxygen or the concentration of N 2 .
• a first technique consists in involving a reducing agent on the gases emitted so that the NOx are converted into nitrogen.
• This reducing agent may be ammonia but this induces disadvantages such as the difficulty of storing and handling such a product.
• a natural gas as a reducing agent, but this is done to the detriment of the consumption of the furnace and increases the CO2 emissions.
• the presence of reducing gases in certain parts of the furnace such as the regenerators can also cause accelerated corrosion of the refractories of these zones.
• a first category is to reduce the formation of NOx using the technique known as "reburning" by which one creates a defective air zone at the combustion chamber of a furnace.
• This technique has the disadvantage of increasing the temperature at the regenerator stack and, where appropriate, to provide a specific design of the regenerators and their stacks, particularly in terms of sealing and resistance to corrosion;
• a second category consists in acting on the flame by reducing or even preventing the formation of NOx at its level. For this, one can for example seek to reduce the excess combustion air. It is also possible to seek to limit the temperature peaks by maintaining the flame length, and to increase the volume of the flame front to reduce the average temperature within the flame. Such a solution is for example described in US6047565 and WO9802386. It consists of a combustion process for the melting of the glass, in which the fuel supply and the fuel supply both take place in such a way as to spread the fuel / oxidizer contact over time and / or to increase the volume. contact to reduce NOx emissions.
• an injector is dedicated to the propulsion of fuel, the latter being intended to be burned by an oxidizer.
• the injector may be part of a burner, the term burner generally designating the device comprising both the supply of fuel and that of oxidizer.
• EP921349 (or US6244524) has proposed for the purpose of reducing
• a burner equipped with at least one injector comprising a liquid fuel supply line, of the fuel type, and a spray fluid supply duct arranged concentrically with respect to said liquid fuel supply duct, said liquid fuel feed duct comprising an element pierced with oblique channels to put the liquid fuel in the form of a hollow jet substantially conforming to the inner wall, the generatrix of each of said channels forming an angle of at least 10 °, in particular between 15 and 30 °, preferably 20 °, with the supply direction of the liquid fuel.
• the object of the invention is to further reduce NOx from what can be done based on EP921349 (or US6244524). It has indeed been found that the reduction of the angle of the oblique channels with respect to the direction of supply of the liquid fuel makes it possible directly to lengthen the flame produced, to improve the homogeneity of the flame temperature and to reduce the NOx.
• Another object of the invention is to provide an oven and a combustion method, suitable for all configurations of molten mineral glass preparation, which make it possible to obtain an optimal heat transfer, in particular by providing a flame of adequate length and large enough to promote maximum coverage of the glass bath and vitrifiable melt.
• the injector according to the invention can be used in any type of glass furnace such as loop furnaces and furnaces with transverse burners, they can be equipped with regenerators or recuperators.
• the invention relates to a liquid fuel atomizer injector comprising a liquid fuel feed duct and a spray fluid supply duct, said liquid fuel supply duct comprising an element pierced with oblique channels for putting said fuel in the form of a jet hollow in rotation before ejection out of said injector, the generatrix of each of said channels forming an angle of less than 10 ° with the supply direction of the liquid fuel.
• the injector comprises a liquid fuel supply duct, in particular of the fuel oil type, and a spray fluid supply duct arranged generally concentrically around the liquid fuel supply duct, said liquid fuel supply duct comprising the element pierced with oblique channels to put the liquid fuel in the form of a hollow jet substantially conforming to the inner wall, the generatrix of each of said channels forming an angle of less than 10 ° with the supply direction of the liquid fuel.
• the liquid fuel and the sputtering fluid both open through an outer face of the injector.
• the spray fluid exits through a concentric orifice around that of ejection of the liquid fuel. It is advantageous for the external face of the liquid fuel supply duct and the external face of the injector to be in the same plane.
• the liquid fuel feed duct may also end with a nozzle for ejecting the liquid fuel through its outer face.
• the outer face of the liquid fuel supply duct is the outer face of the nozzle.
• the spray fluid supply duct may terminate in a block pierced with an orifice ejecting the spray fluid, at least a portion of the nozzle inserted in said block, the outer face (end portion) of the nozzle being aligned in the plane defined by the outer face of the block (devoid of contact with the spray fluid) and on which opens the orifice.
• the external face of the injector here corresponds to the addition of the outer faces of the nozzle and the outer face of the block.
• the outer face of the supply duct liquid fuel is here the outer face of the nozzle, since the liquid fuel supply conduit ends with a nozzle.
• the liquid fuel can be ejected with a driving power pressure of at least 1.2 MPa.
• the liquid fuel is ejected at a temperature of between 100 and 150 ° C., more preferably between 120 and 140 ° C.
• This viscosity can advantageously be at least equal to 5.10 "6 m 2 / s, especially between 10 ⁇ 5 and 2.10 " 5 m 2 / s.
• the angle of the ejection opening cone of the liquid fuel is correlated with the angle made by the oblique channels in the element to put the liquid fuel in the form of a hollow jet with the direction of supply of liquid fuel.
• the liquid fuel is ejected according to a cone with an opening angle of less than 10 °, in particular between 3 ° and 8 °.
• An opening angle of about 5 ° is particularly well suited.
• Such values make it possible, independently of the geometry of the liquid fuel supply duct and its dimensioning, not only to systematically have an interference between the jet of spray fluid and the droplets of liquid fuel, which interference is necessary in the context of the invention, but also a dispersion of the size of these same droplets so that the resulting flame is homogeneous in temperature over its entire length.
• the spraying fluid it is ejected, very advantageously at a flow rate of at most 70 Nm 3 / h, generally between 30 and 60 Nm 3 / h.
• the value of the flow of the spraying fluid is correlated with that of the pressure of the same fluid, which pressure must be limited to the maximum.
• the liquid fuel supply duct may comprise a cylindrical tube and a nozzle.
• the nozzle may be fixed, in particular by screwing, at the end of the cylindrical tube.
• a geometry of the nozzle particularly adapted to the injector according to the invention is such that it comprises a frustoconical gyration chamber extended by a tip whose inner wall is cylindrical.
• the liquid fuel flow is hollow as soon as it is rotated, that is to say as soon as it leaves the element pierced with oblique channels, and until expelled from the injector, that is, its droplet spraying.
• the apex angle teta of the gyration chamber is at least 30 °, preferably between 55 and 65 °, in particular 60 °, which makes it possible to minimize the pressure losses of the fuel. flowing liquid.
• the element responsible for forming the hollow jet rotating liquid fuel substantially closes the liquid fuel feed conduit and is pierced with channels, in particular cylindrical, oblique with respect to the direction of supply of the liquid fuel.
• This element gives the liquid fuel a rotating flow enabling it to take the form of a hollow jet and gives it a level of mechanical energy that is high enough for it to be sprayed at the outlet of its supply conduit under the Droplet shape with optimal size dispersion.
• the channels may advantageously be uniformly distributed over the circumference of the element.
• This element is shaped to allow its insertion into the liquid fuel supply duct and may for example be a cylinder, preferably two sides substantially parallel to each other (pellet-shaped). These faces are by Elsewhere oriented preferentially in a direction perpendicular to the supply direction of the liquid fuel.
• the element comprising the channels may therefore in particular have a cylindrical shape whose axis corresponds to the direction of supply of the liquid fuel.
• the orientation of each of the channels is chosen so that their generatrix makes an alpha angle of less than 10 °, and even less than 8 °, or even less than 6 °, especially about 5 ° with the supply direction of liquid fuel.
• the orientation of each of the channels is chosen so that their generator makes an alpha angle of more than 2 °, or even more than 3 °, or even more than 4 ° with the direction of fuel supply liquid.
• each channel is defined in particular by an orifice on each side of the element, that is to say by two orifices per channel.
• the center of the orifices of all the channels located on one side of the element are regularly distributed on a circle whose center corresponds to the axis of the element and the injector.
• the radius R of these two circles may be identical.
• R can range from 2.5 to 4.5 mm. If S represents the area of all the channels included in the element, then it is preferred to choose the S / R ratio ranging from 6 to 13 mm.
• the element can be mounted, upstream of the nozzle, in a sealed manner in the liquid fuel feed duct, preferably against the turning chamber.
• downstream and upstream must be understood by reference to the direction of supply of the liquid fuel.
• the spray fluid supply duct preferably comprises at least one cylindrical tube at the end of which is fixed, preferably by screwing, a block pierced with an orifice in which at least a portion of the nozzle according to the invention is inserted.
• the orifice of the block and the outer wall of the portion of the nozzle which fits into it are arranged concentrically.
• This preferred arrangement can also be obtained by the aforementioned screwing capable of ensuring the self-centering of the elements described above, namely the orifice of the block relative to the part of the nozzle which fits into it.
• This concentricity is advantageous insofar as in its absence there is a risk of formation of very large droplets of the liquid fuel, of the fuel type, at the periphery of the hollow jet, which can lead to a poor combustion with a particular risk of increase in the threshold of appearance of carbon monoxide.
• the outer face (end portion) of the nozzle is aligned in the plane defined by the outer face of the block, that is to say that devoid of contact with the spray fluid, and on which opens the orifice.
• incorrect alignment involves a modification of the aerodynamics of the liquid fuel and of the spray fluid at their outlet from their respective supply duct.
• the injector according to the invention which has just been described is mounted in a sealed manner in a block of refractory material by means of a sealing device comprising a plate provided with cooling fins.
• a sealing device comprising a plate provided with cooling fins.
• the injector according to the invention can be fixed on an adjustable support, a ventilation nozzle being directed towards the downstream end of the injector, more particularly towards the aforementioned plate.
• the support is preferably adjustable in inclination, azimuth and translation in particular to come to rest on the plate of the sealing device.
• the ventilation nozzle meanwhile, blows air, which avoids excessive overheating locally at the downstream end of the injector.
• the liquid fuel supply duct may comprise at least one diffuser.
• the liquid fuel used in the context of the invention is a liquid fossil fuel commonly used in combustion devices for heating vitrifiable materials in a glass furnace. It may for example be heavy fuel oil.
• the spraying fluid is, likewise, that found in the usual manner on current installations and used to spray the aforementioned liquid fuel. This can for example be air (called in this case primary air as opposed to the secondary air that serves as the main oxidant). It can also be natural gas, oxygen (in the case of oxyfuel combustion) or steam.
• the invention is particularly applicable to heavy fuel type fuels and it allows to circulate very large flows (500 to 600 kg / h) of this type of fuel on a single injector according to the invention.
• the flow rate of liquid fuel in the injector is to be determined from the type of furnace on which it is desired to install it, its operating parameters such as pulling, as well as the nature of the liquid fuel used. These values can be established without difficulty by those skilled in the art who can in particular establish abacuses by carrying out tests. Those skilled in the art will also take care to choose a state of neat surface, respectively of the gyration chamber, the channels, and the tip of the internal walls, so as to ensure a minimum of pressure losses due to rubbing liquid fuel sweeping these same elements at high speed.
• the injector according to the invention generates little NOx in the combustion chamber, for example an oven, its operation is ensured with a low spray fluid flow, which makes possible a wide and flexible use of the oxidant and, therefore, in the end allows to obtain good results from the energy point of view.
• the injector is generally integrated with a burner further comprising an oxidizer inlet.
• This oxidizer may be air, air enriched with oxygen or pure oxygen.
• the injector is placed under the arrival of oxidizer.
• the air supply is provided by an opening of relatively large section, which can be between 0.5 and 3 m 2 , several injectors can be combined with each air intake.
• the invention is particularly suitable for the manufacture of high quality glass including optical, such as float flat glass, or hollow glass.
• optical such as float flat glass, or hollow glass.
• the furnace equipped with the injector according to the invention emits little NOx, without fear of a reducing combustion which may be detrimental to the color of the glass.
• the invention may especially advantageously complement the techniques described in US6047565 and WO9802386.
• Figure 1 is a schematic partial sectional view of an injector according to the invention.
• FIG. 2 represents an element according to the invention pierced with channels putting the fuel in a hollow jet seen from the side in section (FIG. 2a) and seen from above (FIG. 2b).
• FIG. 3 is a vertical sectional view of a wall of a glassware furnace comprising an injector according to FIG.
• FIG. 1 shows a partial sectional view of an injector 1 according to the invention.
• This injector 1 is composed of two fluid feeds, namely respectively the supply duct for the liquid fuel 2 and that of the spraying fluid 3.
• the supply ducts of the aforementioned liquid fuel and spray fluid are respectively connected, upstream of the flow of each of the two fluids, to a circuit from a source of liquid fuel and a spray fluid source not shown.
• the liquid fuel supply duct 2 consists essentially of a cylindrical tube 21 at the end of which is screwed a nozzle 22.
• the latter has at its downstream end a frustoconical gyration chamber 23 extended by a wall endpiece 24 25 cylindrical internal.
• the teta apex angle of the turning chamber 23 is equal to 60 °.
• a cylinder 4 sealingly mounted abutting against the swirl chamber 23.
• This cylinder 4 is the pierced element of oblique channels putting the liquid fuel in the form of a jet hollow.
• the cylinder 4 has channels 41 uniformly distributed over its circumference and has two faces 42, 43 parallel to each other and substantially perpendicular to the direction of supply of the liquid fuel symbolized by the arrow f in Figure 1, direction also identical to that of supply of the spray fluid.
• the channels 41 are cylindrical, their generatrix making an alpha angle of 5 ° with the supply direction mentioned above.
• the spray fluid supply duct 3 for its part, consists essentially of a cylindrical tube 31 at the end of which is screwed a block 32 whose inner shoulder 33 abuts against the downstream end of the tube 31.
• the block 32 is pierced with a hole 34 of shape allowing the nesting of a portion of the nozzle 22.
• the block 32 also has on the side of the orifice 34 a projecting portion 35 which allows by screwing the block 32 on the cylindrical tube 31 to ensure a self-centering part of the outer wall 26 of the nozzle 24 inside the orifice 34.
• Such an arrangement contributes to maintaining the aerodynamics of the two fluids at their outlet from their respective supply duct.
• Figure 2 shows the cylinder 4 of Figure 1 in more detail, side view in section (Figure 2a) and top view ( Figure 2b). We see in the figure
• the cylinder has 8 channels 20 whose centers are regularly distributed on a circle of radius R. It is shown in Figure 2b that the emerging orifice of these channels that is to say the orifice out at above the part, except for one of these channels for which the upper orifice 21 is drawn by a continuous circle and the lower orifice 22 is drawn by a dashed circle.
• FIG. 2a shows the cylinder seen from the side, only the channel with the orifices 21 and 22 having been represented.
• the axis of this channel forms an alpha angle with the axis of the cylinder itself which corresponds to the supply direction of the liquid fuel.
• the angle alpha is less than 10 °.
• FIG. 3 represents a vertical sectional view of a wall of a glassmaking furnace comprising an injector 5 according to FIG. 1.
• the injector 5 comprises a support 6 that is adjustable in inclination, azimuth and in translation.
• the injector 5 which abuts against the walls of a block 7 of refractory material, through a plate 8 provided with cooling fins.
• the block 7 of refractory material is itself mounted in an opening of the wall of the furnace 9.
• the injector 5 also comprises a ventilation nozzle 10 directed towards the aforementioned plate.
• the liquid fuel, supplied via the cylindrical tube 21, is divided into as many individual jets as there are tangential channels 41.
• the individual jets then arrive in the gyration chamber 23 by striking its walls, with a minimum of losses due to the fact that the value of the angle at the top teta equal to 60 °.
• This centrifugation at the level of the gyration chamber contributes, downstream, so that the fuel follows a helical path in the form of a hollow jet conforming to the inner wall 25 of the nozzle 24.
• the liquid fuel has thus acquired a maximum mechanical energy and, under the influence of the spraying fluid, it really bursts into very fine droplets whose size dispersion is optimal.
• Such a dispersion makes the flame coming from the injector and once activated by the main oxidant, very homogeneous in temperature throughout its length.
• Such a fuel spraying extends considerably more, for the same fuel flow, the flame compared to a spray that would be caused by the same injector 1 without cylinder 4.
• the dimensioning of the cylinder 4 must be such that the filling is never performed and that we obtain, according to the invention, always a hollow jet substantially matching the inner wall.
• the injector which has just been described is of simple and inexpensive design.
• This burner has a power of 15 megawatts.
• Each injector contains a fuel rotation element comprising 8 2.3 mm diameter holes whose axis forms an angle of 5 ° with respect to the direction of supply of the liquid fuel oil. The axes of these holes are arranged on a circle of 3.75 mm radius.
• the total fuel oil flow (sum of flows feeding all injectors) was 2000 kg / h.
• the NOx measured in the fumes was 550 mg per Nm 3 .
• Example 2 The procedure is as for Example 1 except that the holes had an axis forming an angle of 20 ° with respect to the supply direction of the liquid fuel oil.
• NOx measured in fumes was 800 mg per Nm 3 .

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Nozzles For Spraying Of Liquid Fuel (AREA)
• Nozzles (AREA)
• Jet Pumps And Other Pumps (AREA)
• Pressure-Spray And Ultrasonic-Wave- Spray Burners (AREA)
• Clamps And Clips (AREA)
• Fuel-Injection Apparatus (AREA)
• Telephone Function (AREA)

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• 2007
  • 2007-03-26 FR FR0754028A patent/FR2914397B1/fr not_active Expired - Fee Related
• 2008
  • 2008-03-21 UA UAA200910734A patent/UA97977C2/ru unknown
  • 2008-03-21 EA EA200970888A patent/EA015872B1/ru not_active IP Right Cessation
  • 2008-03-21 CN CN200880009965XA patent/CN101680654B/zh not_active Expired - Fee Related
  • 2008-03-21 AT AT08775732T patent/ATE473397T1/de not_active IP Right Cessation
  • 2008-03-21 DE DE602008001722T patent/DE602008001722D1/de active Active
  • 2008-03-21 JP JP2010500329A patent/JP5603230B2/ja not_active Expired - Fee Related
  • 2008-03-21 EP EP08775732A patent/EP2126470B1/de active Active
  • 2008-03-21 MX MX2009010318A patent/MX2009010318A/es active IP Right Grant
  • 2008-03-21 BR BRPI0809072-6A patent/BRPI0809072B1/pt not_active IP Right Cessation
  • 2008-03-21 WO PCT/FR2008/050492 patent/WO2008132388A1/fr active Application Filing
  • 2008-03-21 PL PL08775732T patent/PL2126470T3/pl unknown
  • 2008-03-21 ES ES08775732T patent/ES2348575T3/es active Active
  • 2008-03-21 US US12/593,488 patent/US20100112498A1/en not_active Abandoned
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