Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D17/00—Burners for combustion conjointly or alternatively of gaseous or liquid or pulverulent fuel
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
  • F23C7/00—Combustion apparatus characterised by arrangements for air supply
  • F23C7/002—Combustion apparatus characterised by arrangements for air supply the air being submitted to a rotary or spinning motion
  • F23C7/004—Combustion apparatus characterised by arrangements for air supply the air being submitted to a rotary or spinning motion using vanes
  • F23C7/006—Combustion apparatus characterised by arrangements for air supply the air being submitted to a rotary or spinning motion using vanes adjustable
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/46—Details, e.g. noise reduction means
  • F23D14/60—Devices for simultaneous control of gas and combustion air
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D17/00—Burners for combustion conjointly or alternatively of gaseous or liquid or pulverulent fuel
  • F23D17/005—Burners for combustion conjointly or alternatively of gaseous or liquid or pulverulent fuel gaseous or pulverulent fuel
• • 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
  • F23D2900/21—Burners specially adapted for a particular use

Definitions

• the present invention relates to the field of burners of any field and any fuel and including but not limited to burner for rotary kiln (or rotating), such as cement kilns or lime kilns.
• this hot secondary air represents between 80 and 95% of the furnace combustion air.
• the complementary air is the air injected directly into the burner at a lower temperature (temperature close to ambient temperature in most cases) but at high speed.
• this primary air is injected at the end of the burner, at high pressure (between 100 and 500 mbar) and at high speed (between 80 and 350 m / s) in order to:
• the flame shape such as its width and length, and adapt to the specific conditions of the furnace.
• Rotary kiln burners are typically characterized by their primary air impulse which is the force generated by the air expansion primary in the furnace (primary air mass flow rate x primary air expansion velocity) divided by the heating capacity of the burner.
• the primary air at high pressure and low temperature impacts the energy balance of the process by the electrical consumption necessary to put it in pressure as well as by the introduction of cold air into the process.
• the primary air injections at the end of the rotary kiln burners generally consist of at least two primary air outlets, at least one of which is axial and the other radial (or rotational). In this case, adjusting the proportion between the flow rate and / or the axial and radial air pressure allows adjustment of the overall radial component of the primary air and varies the flame shape.
• the provision of radial air within the fueled fuel system increases the risk of ejection of fuel out of the flame, which can create adverse operating conditions (deterioration of the cooking quality of the product). , operating difficulties, reduction of the lifetime of the brickwork lining the furnace ...) and increases the NOx emissions, because the concentration of fuel is too low in the center of the flame which prohibits the phenomenon of NOx-reducing combustion .
• Primary air injections at the end of the rotary kiln burners may also have a single primary air outlet with an adjustable radial component. In that case:
• the radial component is obtained by an axial / radial mixture upstream and we find the same problem as on burners with two primary air outlets, namely a loss of efficiency related to the use of organ regulating creating losses and lowering the rate of expansion of the primary air,
• the radial component is obtained by orientation of the burner outlet sections. This orientation must be done without any particular pressure loss so that the burner has a primary air expansion rate at the optimal nozzle, and a better energy efficiency.
• the control of the flame diameter is more difficult in burners with single primary air outlet with adjustable radial component. Indeed, if in burners with two or more outlets, the axial outlet is generally located at the periphery of the burner to control and stabilize the divergence of the flow and allow a more effective and finer adjustment of the flame diameter, this advantage does not exist on single-outlet burners, making it more difficult to adjust the diameter.
• An excessive flame diameter can have serious consequences on the operating conditions of the process (affecting the nature of the material to be cooked and / or the operating conditions) and or the life of refractory furnace coatings.
• part of the combustion air can also be rotated to provide turbulence and better mixing of air and fuel.
• the present invention also applies to these burners, whether the air is called primary air, combustion air or radial air or rotational air, or staged air.
• combustion air In the following description this portion of combustion air will be called primary air.
• the object of the present invention is to provide a burner which makes it possible to progressively and linearly adjust the radial component of the primary air or of the gas and to avoid a setting by reducing the pressure (and therefore the speed of expansion ) of a radial or axial component and therefore to keep the maximum pulse of the primary air or gas.
• the burner according to the invention comprises a primary air or gas pipe of X axis delimited by an outer wall and a concentric inner wall and radial primary air injection ducts, it is characterized in that the duct primary air or gas comprises a ring rotatable and having axial protuberances constituting distributors that cooperate with the radial primary air ducts or gas disposed at the end of the burner on the outer peripheral portion of the inner wall and form two channels of different angles in each conduit.
• the rotation of the crown will allow to distribute the section of radial primary air ducts in two sets of interposed channels.
• the crown is also mobile in translation.
• the translation of the ring will allow to change the passage section of the radial primary air ducts or gas.
• the passage section is the sum of the sections of the ducts constituting the primary air duct or gas, and it is lower than the outlet section, the passage section is adjustable.
• a first set of channels has a low radial primary air injection angle (typically between -10 and + 30 °) while the other series has a larger radial primary air injection angle than the previous series (generally between +10 and +60 °).
• the angle of injection of the radial primary air or the resulting gas is the combination of the air jets from the two sets of intercalated channels, one at low angle and the other at high angle.
• the rotational adjustment of the ring around the X axis makes it possible to vary the section distribution, and therefore the primary air flow rate or the gas flow between these two series of ducts and thus to adjust the injection angle of radial air.
• the adjustment is located just at the end of the burner, at the primary air outlet or the gas in the oven, by this position of the adjustment at the end one maximizes the output speed of the air or gas and so the impulse.
• the two channels are formed by a complementary flared shape of the distributor and the radial primary air ducts and the sum of the sections of said channels is constant in a plane. perpendicular to X, regardless of the angular position of the crown (3).
• the distributors and the primary air or radial gas ducts are of complementary flared shape which form channels of constant section.
• the adjustment is made by changing the output angle of the radial component with a constant output section which greatly simplifies the adjustment of the burner.
• the distributors and the primary air ducts or radial gas have walls with parallel edges.
• the distributors and the radial primary air ducts have curvilinear edges. This form makes it possible to limit the losses of loads.
• the movable ring has at least one inclined groove and is actuated in rotation by a movable ring in translation to which it is connected by a sliding nut in said groove.
• the translation of the ring allows in this way the rotation of the crown.
• the movable ring is actuated by a jack.
• the jack can be hydraulic, or mechanical, or pneumatic.
• the radial primary air ducts and the distributors are chamfered upstream.
• the chamfer is in a tangent plane or in a vertical plane relative to the flow of air, and it allows a gradual entry and acceleration of air in the channels and therefore a limited pressure drop.
• the burner also comprises axial primary air ducts.
• the radial primary air duct is sandwiched between the fuel ducts and the axial primary air duct.
• the axial primary air ducts and radial primary air are fed by the same power supply.
• This is very advantageous, especially in the context of a burner with two primary air outlets (An axial and the other radial), located outside the fuel circuits because it allows to lighten the burner and limit the pressure drop in the supply circuits, to have a burner whose settings are simple. It is thus possible to adjust the rotation of the ring gear to increase the radial component and act on the flame diameter and to adjust the air pressure upstream of the burner for adjusting the pulse.
• This makes it possible to limit the maximum rotation by a constant proportion between the axial external circuit and the internal circuit with an adjustable radial component and to limit the maximum flame diameter and thus to protect the furnace refractories from false maneuvers and / or incorrect adjustment.
• the number of radial primary air ducts or of gas is a multiple of the number of axial duct or of an axial duct group.
• the radial or gas and axial primary air ducts are arranged on the same spokes.
• the number of radial or tangential component air outlet openings may be matched with the number of holes (or group of holes) of the axial air circuit, so that the primary air pulse of the two circuits best contribute to the absorption of secondary air.
• the angular implantation of the axial air and radial air orifices is important and the arrangement with the orifices (or group of orifices) axial and radial on the same radius is advantageous, that is to say that the radial air ducts are located radially directly below the axial air injection ducts.
• the inclination and the length of the groove is proportional to the rotation of the crown.
• the groove can have a length of 50 to 300mm and a low inclination of 1 to 15 ° with respect to the X axis.
• the combination of a long groove and a low angle makes it possible to obtain a high accuracy of adjustment.
• the duct has an outlet section, this outlet section varies as a function of the displacement of one wall relative to the other, the radial inner face of the distributors and the face outer radial notches make an angle with the X axis and the inner radial face of the outer ring makes an angle ⁇ with the X axis.
• the radial primary air or gas circuit the outlet section can be adjusted to maintain a pressure and thus a maximum injection rate of the primary air or gas at the end of the burner.
• This section modification is obtained by relative displacement along the X axis of the inner and outer tubes of the circuit and an inclined shape along the X axis of the splitters mounted on the movable ring and notches of radial primary air or gas disposed on the outer peripheral portion of the inner tube of the circuit.
• the radial or gas primary air duct is arranged outside fuel circuits (pulverized solid, liquid or other gas). This limits any risk of spraying liquid or solid fuel at the periphery of the flame when increasing the radial component of the air or gas.
• this arrangement makes it possible to reduce NOx by a staged combustion effect by concentrating the fuel in the center of the flame.
• the radial primary air duct is sandwiched between an axial air duct and the center of the burner comprising the combustible ducts (pulverized, liquid or gaseous solid) and possibly the flame stabilizer.
• the splitters and radial primary air ducts are of complementary flared shape forming two channels and whose sum of the sections is variable in a plane perpendicular to X, regardless of the angular position of the ring.
• the primary air radial or gas circuit, the outlet section must be adjustable to maintain a pressure and therefore a maximum injection rate of the primary air or gas at the end of the burner.
• This section modification is obtained by a relative displacement along the axis X of the mobile ring and notches of radial primary air or gas, arranged on the outer peripheral portion of the inner tube of the circuit.
• FIG. 1 is a sectional view of an air or burner gas circuit according to the invention
• FIG. 2 is a front view of the burner according to a particular arrangement
• FIGS. 3 to 5 show different positions of a distributor with curvilinear edges in a radial primary air duct
• FIGS. 6a and 6b are developed views of the distributor in the two extreme positions
• Figure 7 a view of the crown
• FIG. 8 is a view of the main conduit.
• Figures 9 to 12 show front views of different arrangements of primary air and fuel air to the burner.
• Figures 12 and 13 show a sectional view of the burner in a particular arrangement where the section of the air or gas circuit is adjustable.
• Figure 12 is in maximum section position
• Figure 13 is in minimum section position
• Figures 14 and 15 show a sectional view of the burner in a particular arrangement where the section of the air or gas circuit is adjustable by axial displacement of the splitters.
• Figure 14 is in the maximum section position
• Figure 15 in the minimum section position.
• Figures 16a and 16b show different positions of the curvilinear edge distributors in a radial primary air duct.
• Figures 17 and 18 show a sectional view of the burner in a particular arrangement where the section of the air or gas circuit is adjustable.
• the section of the air or gas circuit is adjustable.
• downstream the parties placed on the side of the arrival of primary air and “upstream” those placed on the side of the primary air outlet.
• the burner 1 comprises at least one primary air or gas duct 22 between an outer wall 52 and an inner wall 23 of axis X and constituting concentric tubes of cylindrical shape, surrounding the center of the burner 10 in which may be implanted several other primary air ducts or fuel 100, 101 or a stabilizer 8.
• the end of this duct oven side is closed by an inner end ring 2 and an outer end ring 5, which may be following the embodiments, two separate parts to facilitate machining or the same piece.
• the primary air duct or gas comprises a ring 3, itself surrounded by a ring 4.
• the downstream end of the duct is ringed with the ring 5.
• the inner ring 2 connected to the inner tube of the wall 23 has on its periphery notches 20 which have two faces 200 and 201 flared relative to each other (or V-shaped), which are closed on their peripheral part by the ring 5 and thus constitutes ducts 21 of radial primary air.
• the outer ring 5 comprises primary air ducts 50 with axial component.
• the ring 3 (see FIGS. 1, 2 and 7) has protrusions 30 of flared or V-shaped shape which are arranged in the notches 20 and constitute air distributors 30.
• Each protrusion 30 has two faces 300 and 301. which join respectively downstream and which are respectively parallel to the faces 200 and 201 of the notch 20.
• the V-shape therefore has its tip disposed downstream.
• the ring gear 3 rotates about the axis X on the main duct between two extreme positions, in which the distributor 30 abuts on the face 200 of the notch 20 or on the face 201 of said notch 20.
• crown 3 has at least one groove 31 disposed inclined with respect to the axis X.
• the ring 4 slides from upstream to downstream on the wall 23 along the axis X.
• the ring 4 comprises a stud, nut or key 42 which slides in the groove 31.
• the ring 4 is fixed to at least one arm or control bar 43 connected to a piston (not shown) in order to slide the ring 4 from upstream to downstream and vice versa.
• Each air distributor 30 makes it possible to separate the flow of primary air or gas that arrives in the duct 21 of radial primary air or gas and to give it a radial angular component by dividing it into two channels 210 and 21. with different angles. These channels 210 and 21 1 generate two jets which recombine in a single jet at the exit and whose average angle is substantially proportional to the exit angle of each weighted V of the flow of each jet.
• the section distribution between the two channels 210 and 21 1 is varied, the overall section of the channels 210 and 21 1 being constant over the entire adjustment and therefore the flow rate in each of the branches of the V for obtain a variation of the outlet angle of the air flow 6 without reducing the ejection speed and keeping the flow rate constant.
• the channels 210 and 21 1 are curved in order to reduce the pressure drop in the channels by the progressivity of the speed-up along the radial component and to allow a greater aerodynamic stability of the jet.
• the curved shape gives the lower surface of the jet a slightly lower expansion speed than the extrados of the jet. This makes less turbulent mixing of the two jets at different angles and thus more stable the resulting flow and more optimal the average speed of the jet.
• the distributor 30 is placed substantially in the middle, the amount of air passing through the two channels is substantially identical.
• the distributor 30 is pressed against the wall 200 and the majority of the air passes through the channel 210 more inclined, the air flow 6 is more strongly inclined.
• the distributor 30 is pressed against the wall 201 and the majority of the air passes through the channel 21 1 less inclined, the air flow 6 is very slightly inclined.
• bevels 303, 203 are provided at the inlet of the air distributor 30 and at the inlet of the channels 210 and 21 1 in a tangent plane or in a vertical plane.
• the burner comprises an outer protective concrete 7, the outer ring 5 with axial ducts 50, the inner ring 2 with the radial primary air ducts 21, and the center of the burner 10 delimited externally by the wall 23 comprising a powdery and / or gaseous fuel circuit 100, and other fuel circuits 101 and a central stabilizer 8.
• This type of burner can be used both if it is primary air outlet or single gas with primary air ducts 21 or multiple with primary air ducts or gas 21 and 50.
• the ducts 50 and 21 may be supplied with primary air by a single primary air circuit 22 or by separate primary air circuits, generally concentric or almost concentric with respect to the primary air.
• FIGS. 9 to 11 show different radial arrangements of the primary air or gas circuits according to the invention and of the annular fuel circuit or circuits (pulverulent, gaseous fuels).
• FIG. 9 shows an arrangement with, from the center of the burner, at the stabilizing center 8, fuel circuit 101 in the stabilizer, a powdery fuel circuit 100, a primary air or radial gas circuit with conduits 21, an axial circuit with conduits 50.
• FIG. 10 shows an arrangement with, from the center of the burner, at the stabilizing center 8, fuel circuit 101 in the stabilizer, a primary air or radial gas circuit with conduits 21, a powdery fuel circuit 100, an axial circuit with ducts. 50.
• FIG. 11 shows an arrangement with, from the center of the burner, at the stabilizing center 8, fuel circuit 101 in the stabilizer, a pulverulent fuel circuit 100, a primary air or radial gas circuit with conduits 21 without an axial circuit.
• the minimum section of the radial component in the plane 216 can be adjusted at the end of the burner to maintain a pressure and therefore a maximum injection rate of primary air or gas at the end of the burner.
• This section modification is obtained by the displacement along the X axis of one of the walls 23 or 52 with respect to the other, the inclination angle ⁇ of the inner radial face 315 of the splitters 30 and the outer radial face 215 notches of radial primary air or gas 20 relative to the axis X, and a divergent angle ⁇ on the inner radial face 51 of the outer ring 5.
• the inner wall 23 is movable and the outer wall 52 is fixed.
• the ring 3 also translates along the X axis on the main conduit between two extreme positions, in which the face 310 of the distributor 30 abuts on the face 220 to obtain a minimum passage section.
• Dispatcher 30 can be moved back for an increased passage section.
• the translation of the crown 3 or the rotation thereof can be done through two relative movements independent. Adjustment of the section may be performed by translation and / or rotation of the crown.
• the section of the radial component may be adjusted at the end of the burner 1 to maintain a pressure and thus a maximum injection speed primary air or gas at the end of the burner.
• This modification of section is obtained by the translation along the axis X of the ring gear 30 connected to the control bar 43. In the retracted position, FIGS. 14, 16a and 17, the section of the channels 210, 21 1 are maximum, while when they are pushed, FIG. 15, 16b and 18, the section of the channels 210, 21 1 are minimum.
• FIGS. 17 and 18 show that the translational movements of the ring 30 are along the X axis and are controlled by the tube or the control bar 43, and that the rotation of the ring 30 is obtained by the translation of the tube or of the control bar 43.
• the optimal arrangement for the suction of secondary air in the flame is the implantation of this primary air circuit outside the fuel circuits and in particular the powder circuit. This arrangement limits the projection of solid fuels outside the flame and reduces the formation of nitrogen oxides.
• the number led 21 is a multiple of the number of axial ducts 50 or axial duct group 50, to improve the secondary air absorption.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Pre-Mixing And Non-Premixing Gas Burner (AREA)
• Gas Burners (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

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• 2014
  • 2014-08-06 FR FR1401811A patent/FR3024765B1/fr active Active
• 2015
  • 2015-06-25 DK DK15756185.3T patent/DK3177872T3/da active
  • 2015-06-25 WO PCT/FR2015/051726 patent/WO2016020587A1/fr active Application Filing
  • 2015-06-25 EP EP15756185.3A patent/EP3177872B1/de active Active
  • 2015-06-25 CN CN201580054153.7A patent/CN106796025B/zh active Active
  • 2015-06-25 RU RU2017104450A patent/RU2678466C2/ru active
  • 2015-06-25 ES ES15756185T patent/ES2648462T3/es active Active
  • 2015-06-25 BR BR112017002300-8A patent/BR112017002300B1/pt active IP Right Grant
  • 2015-06-25 US US15/501,311 patent/US10234137B2/en active Active
  • 2015-06-25 DE DE15756185.3T patent/DE15756185T1/de active Pending

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