JP2017122565A - Burner device for rotary kiln and in-furnace combustion method for rotary kiln - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a burner device for a rotor rotary kiln capable of easily changing setting of shape, position and/or temperature distribution of flame.SOLUTION: A burner device (B) has an air injection port (4-8) for injecting air jet (A1, A2, C), first and second fuel injection ports (2, 3) for injecting a fuel (G) to different angular directions (θ) with respect to a central axis (X) of the burner device, and a control device (C/U) for controlling a relative fuel flow rate ratio of the fuel injection ports. The first fuel injection port (2) injects a first fuel jet flow (G1) of the central axis (X) direction into a furnace, and the second fuel injection port (3) injects the second fuel jet flow (G2) of the inclination angle (θ) into the furnace. The shape, position and/or temperature distribution of flame (F) are changed by changing the flow rate ratio of the fuel jet flows (G1, G2).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a burner device for a rotary kiln and a combustion method in the furnace, and more specifically, the shape, position and / or temperature distribution of a flame generated in the furnace area of the rotary kiln can be variably controlled. The present invention relates to a burner device for a rotary kiln and a furnace combustion method thereof.

  Rotating an inclined cylindrical furnace, and injecting liquid fuel such as heavy oil, solid powder fuel such as pulverized coal, or gas fuel such as city gas into the furnace, the object to be heated, the heat receiving material, and firing in the furnace 2. Description of the Related Art A rotary kiln (rotary kiln) that heats, burns, or incinerate an object or an incinerated object (hereinafter referred to as “object to be heated”) is known. In general, a burner device for a rotary kiln (hereinafter referred to as a “burner device”) is disposed in the central region of the end of the rotary kiln, and injects fuel and combustion air in the direction of the central axis of the furnace and flames in the furnace region. Is generated.

  Generally, a burner apparatus using a solid powder fuel such as pulverized coal as a main fuel injects primary array air at an ordinary temperature (atmospheric temperature) and an annular array or annular arrangement of fuel injection ports that inject solid powder fuel such as pulverized coal. An air injection port. The air injection ports are annularly arranged or annularly arranged in the outer annular zone and the inner annular zone of the fuel injection port. In this type of rotary kiln, secondary air is supplied to the annular furnace inner region outside (in the radial direction) of the burner device. In general-purpose rotary kilns used for cement firing and the like, the secondary air is air preheated to 1000 ° C. or more by the waste heat recovery means of the rotary kiln, and on the other hand for specific uses such as production of ceramic raw materials. In the rotary kiln used, the secondary air is air preheated to about 200 ° C. The secondary air after preheating flows into the in-furnace region from the annular region or the annular flow passage around the burner device along the axial direction of the burner device.

  In such a burner apparatus, a burner apparatus in which swirl vanes are arranged at the fuel injection port and the air injection port and the fuel jet and the air jet are injected into the combustion region in the furnace in a swirl flow form is disclosed in, for example, Patent Document 1 No. 2015-25152). This type of burner device is configured to set the swirl characteristics or swirl strength of swirl flow by setting the position and / or direction of swirl vanes, and thereby to set the flame shape, flame diameter, flame length, etc. Has been.

  As a similar burner device, there is a configuration in which swirling air injection ports provided with fixed air flow direction changing means for forming swirling air flow are arranged or arranged annularly in the inner annular zone and the outer annular zone of the fuel injection port. For example, it is described in patent document 2 (Unexamined-Japanese-Patent No. 2003-279003). Also in this burner device, the fuel injection port is configured to inject a solid powder fuel such as pulverized coal in a swirling flow form.

  As a rotary kiln equipped with other types of burner devices, spray type fuel injection ports for injecting liquid fuel such as heavy oil are arranged on the outer periphery of the furnace in order to make the temperature distribution in the furnace uniform and shorten the kiln body length. In addition, a rotary kiln having a configuration in which combustion air injection ports are arranged on the outer periphery of the furnace at a position spaced apart from the fuel injection port is described in Patent Document 3 (Japanese Patent Laid-Open No. 2006-284023). . This rotary kiln is configured to generate a flame in the furnace swirl flow form in the furnace by mixing and contacting the fuel injected in the tangential direction into the furnace and the combustion air.

  Further, in this type of burner apparatus, a configuration using a gaseous fuel such as natural gas (city gas) or LP gas as a main fuel is described in, for example, Japanese Patent Application Laid-Open No. 2006-298685. ing. This burner device is configured to inject gaseous fuel and combustion air (primary air and secondary air) into the furnace in the direction of the central axis of the furnace. A part of the combustion air is injected into the furnace in the form of a swirling flow around the center axis of the furnace, but the combustion air is jetted into the furnace in the direction of the center axis of the furnace as a whole. The fuel and combustion air mixed and contacted with each other generate a flame extending in the central axis direction of the furnace in the central area of the furnace.

JP 2015-25152 Japanese Patent Laid-Open No. 2003-279003 JP 2006-284023 JP 2006-298685 JP

  The hearth part of the rotary kiln extends in the furnace length direction at the lower part of the inner peripheral wall surface of the furnace, and most of the objects to be heated in the rotary kiln are deposited on the hearth part and move or flow along the hearth part. Therefore, the flame position, flame shape, flame length, flame temperature peak position, etc. can be controlled so that a flame or combustion atmosphere at a temperature suitable for heating the article to be heated acts on the article to be heated in the hearth. desirable.

  When optimizing the position or shape of the flame that acts on the object to be heated in the hearth, not only the fuel and combustion air injection amounts are changed, but also the directionality or position of the fuel soot and air jets. In order to change the directionality or position of the fuel flow and air jet, it is necessary to change the directionality or position of each injection port or injection nozzle. However, the directionality or position of each injection port or injection nozzle cannot be changed during the operation of the burner device, and it is difficult to change the setting easily due to the structure of the device even when the burner device is not operating. is there.

  On the other hand, in the burner device described in Patent Documents 1 to 4, it is assumed that the setting of the flame position or flame shape can be changed by changing the setting of the position and / or directionality of the swirl vane, Changing the setting of the position, direction, etc. of the swirl blades can only be carried out at the time of limited apparatus maintenance or apparatus repair.

  On the other hand, it may be considered to design the swirl vane in a movable or switchable structure so that the position or directionality of the swirl vane can be easily changed. However, when a movable member such as a movable swirl vane is disposed in a high-temperature atmosphere injection port or injection nozzle, problems such as maintenance / management, adjustment, strength maintenance, and durability assurance of the movable member or switching member newly arise. Such a design is difficult to adopt in practice.

  The present invention has been made in view of such circumstances, and the object thereof is not dependent on the setting change of the device structure or the device configuration, without using a movable member such as a movable blade, An object of the present invention is to provide a burner device for a rotary kiln capable of relatively easily setting and changing the shape, position and / or temperature distribution of a flame generated in a furnace, and a combustion method in the furnace.

In order to achieve the above object, the present invention has a fuel injection port for injecting fuel, and an air injection port arranged radially outward of the fuel injection port, the fuel jet of the fuel injection port, In the rotary kiln burner device for generating a flame in the rotary kiln furnace by mixing contact with the air jet of the air injection port,
The fuel injection port includes first and second fuel injection ports that inject the fuel in different angular directions with respect to the central axis of the burner device, and the fuel injection amount of the first and second fuel injection ports. A control device for controlling the flow rate ratio or flow rate ratio is provided.
The first fuel jet injected from the first fuel injection port has a central axis substantially parallel to the central axis of the burner device, or in a direction approaching the central axis of the burner device in the jet direction. Having a central axis extending;
The second fuel injection port injects the second fuel jet in a direction that forms a predetermined inclination angle with respect to the central axis of the first fuel jet,
A rotary kiln burner device characterized in that the first and second fuel injection ports change the shape, position and / or temperature distribution of the furnace generated in the furnace by changing the flow rate ratio or flow rate ratio. provide.

The present invention also injects a fuel jet of fuel from a fuel injection port, injects an air jet from an air injection port disposed radially outward of the fuel injection port, and the fuel jet and the air jet In the rotary kiln in-furnace combustion method for generating a flame in the rotary kiln furnace by mixing contact,
The fuel injection port is constituted by first and second fuel injection ports that inject the fuel in different angular directions with respect to the central axis of the burner device,
The first fuel injection port has a center axis that is substantially parallel to the center axis of the burner device, or a first axis that extends in a direction approaching the center axis of the burner device in the jet direction. A fuel jet is injected, and the second fuel injection port injects the second fuel jet in a direction that forms a predetermined inclination angle with respect to the central axis of the first fuel jet,
By controlling the flow rate ratio or the flow rate ratio of the fuel injection amounts of the first and second fuel injection ports, the direction of fuel jet diffusion and the mixing ratio or mixing process of fuel and air are changed, so that Provided is a method for in-furnace combustion of a rotary kiln characterized by changing the shape, position and / or temperature distribution in the furnace of the flame to be generated.

  According to the above configuration of the present invention, the fuel supply port of the burner device is constituted by the first and second fuel injection ports that inject fuel in different angular directions, and the fuel jets injected by the fuel injection ports are air injections. Combustion reaction occurs in contact with the combustion air jetted from the mouth, generating a flame in the furnace. This flame is a substantially single flame formed by synthesizing or assembling the flames generated in the furnace by the combustion reaction of each fuel jet, and the shape, position and / or temperature distribution is determined by each fuel injection port. It changes in accordance with the flow rate ratio or flow rate ratio of each injected fuel jet. The control system of the burner device includes a control device that controls the flow rate ratio or flow rate ratio. The control device changes the direction of jet diffusion by controlling the flow rate ratio or flow rate ratio, or changes the mixing ratio or mixing process of fuel and air by controlling the flow rate ratio or flow rate ratio, thereby changing the flame formation position. And change the flame temperature distribution. Therefore, according to the present invention, the shape, position and / or temperature distribution of the flame can be changed as desired by controlling the flow rate ratio or flow rate ratio of the fuel injection amount of each fuel injection port.

  Thus, according to the above-described configuration of the present invention, the flow rate ratio or flow rate ratio of the fuel injection amount at each fuel injection port can be set without changing the setting of the device structure or the device configuration, without using a movable member such as a movable blade. By changing, it is possible to relatively easily change the setting of the shape, position and / or temperature distribution of the flame generated in the furnace. Moreover, since the shape, position and / or temperature distribution of the flame can be controlled by changing the flow rate ratio or flow rate ratio during the operation of the burner device, it is extremely advantageous in practice.

  Preferably, the central axis of the air jet of the air jet is oriented in a direction substantially parallel to the central axis of the fuel jet of the adjacent or related fuel jet, or the air jet of the air jet Is oriented so as to approach the central axis of the fuel jet in the jet direction. According to such a structure, the combustion reaction by the mixed contact of fuel and combustion air can be promoted.

  Preferably, each jet central axis of the first and second fuel injection ports is oriented in a direction that forms a relative angle within a range of 15 to 60 degrees, more preferably a relative angle of 20 to 45 degrees.

  If desired, the burner device has a combustion control air injection port (control air injection port) that injects combustion air (combustion control air) at a lower speed than the fuel jet of the fuel injection port from the vicinity of the fuel injection port. The combustion control air is jetted in substantially the same direction as the fuel jet, or is oriented so that its central axis approaches the central axis of the fuel jet in the jet direction. In this specification, the description of “substantially parallel” or “substantially the same direction” means that the angle range of about 10 degrees or the difference in angle error is actually the same angle due to the nature of the jet. It is a statement to the effect that it should be understood.

  According to the burner device provided with such a control air injection port, the flame properties can be further controlled by the flow rate or flow velocity of the combustion control air, so that the controllability of the flame shape and the like can be improved. In addition, since the relatively low-speed combustion control air is attracted to the relatively high-speed fuel jet and mixes with the fuel to cause a combustion reaction, the combustion stability of the in-furnace combustion reaction is improved. If desired, preheated air preheated to 100 ° C. or higher may be injected into the furnace as the combustion control air. Preferably, the flow rate of the fuel jet at the fuel injection port is set to a flow rate of 100 m / s or more, and the flow rate of the combustion control air at the control air injection port is set to a flow rate of less than 100 m / s.

  If desired, flow control means for variably controlling the flow rate of the combustion control air is provided, and the flow rate of the combustion control air is controlled to change the mixing ratio or mixing process of the fuel and air, so that the flame formation position, flame temperature distribution or The flame temperature peak position and the like may be changed.

  Preferably, the second fuel injection port is composed of a plurality of fuel injection nozzles arranged on the front end face of the fuel supply pipe, and the fuel injection nozzle injects a fuel jet obliquely downward toward the hearth. Preferably, the first fuel injection port is also composed of a plurality of fuel injection nozzles arranged on the front end surface of the fuel supply pipe. The central axes of the first fuel injection ports or the central axes of the second fuel injection ports may be oriented so as to approach each other in the jet direction.

  If desired, the fuel injection nozzle has premixing means for premixing the combustion air into the fuel, and the premixing means changes the premixing ratio of the combustion air and the fuel to change the flame temperature peak position and the like. Configured to let

  If necessary, swirl vanes that supply the fuel jet into the furnace as a swirl flow may be provided in the fuel injection nozzle, and the fuel jet may be fed into the furnace as a swirl flow. The fuel jet attracts ambient air, thus facilitating the mixing of fuel and air.

  According to a preferred embodiment of the present invention, the burner device has a plurality of first fuel injection ports that inject a first fuel jet, and a plurality of second fuel injection ports that inject a second fuel jet, The first fuel jets are simultaneously injected from the plurality of first fuel injection ports, and the second fuel jets are simultaneously injected from the plurality of second fuel injection ports. Further, in a preferred embodiment of the present invention, the burner device includes a secondary air flow path for supplying secondary air to the secondary air injection port, and a combustion for controlling flame properties, disposed in the secondary air flow path. A control air supply pipe that supplies control air to the control air injection port, a primary air supply pipe that supplies primary air to the primary air injection port, and a primary air supply pipe that is arranged in the control air supply pipe. And a fuel supply pipe for supplying the fuel injection port.

  In another preferred embodiment of the present invention, the burner device includes first and second air injection ports that inject an air jet in different angular directions with respect to the central axis of the burner device as the air injection port. The flow rate ratio or flow rate ratio of the air injection amounts of the first and second air injection ports is controlled by the control device. The control device changes the temperature distribution in the furnace or adjusts the temperature distribution in the furnace by controlling the flow rate ratio or flow rate ratio of the air injection amounts of the first and second air injection ports.

  From another viewpoint, the present invention provides a method for in-furnace combustion in a rotary kiln that eliminates the problem of in-furnace blockage caused by overheating of an object to be heated, using the burner device having the above-described configuration. In the in-core combustion method of the present invention, the flow rate of the fuel injection amount of the first and second fuel injection ports so that the shape, position and / or temperature distribution in the furnace generated in the furnace varies with time. The ratio or flow rate ratio is variably controlled. Overheating of the object to be heated can be prevented or suppressed by fluctuations in the flame shape and the like. Therefore, according to the in-furnace combustion method of the present invention, the phenomenon that the object to be heated melts due to overheating in the in-furnace region portions in the vicinity of the first and second fuel injection ports of the burner device is prevented. It becomes possible to prevent or avoid blockage in the furnace due to the growth or expansion of the molten deposit or molten deposit on the wall surface or hearth. Such prevention of in-furnace blockage is extremely useful in practice because it enables a reduction in the frequency of transient operation stoppage for obstruction removal work or the postponement of this kind of operation stoppage time.

  If desired, the flow rate ratio or flow rate ratio of the fuel injection amount of the burner device is controlled in relation to the production amount of the product or the heating load of the article to be heated. According to such a configuration, it is possible to optimize or optimize the flame shape, position and / or furnace temperature distribution in accordance with the heat load, etc., and to heat the object to be heated at an appropriate firing temperature below the melting point. Therefore, it is possible to effectively prevent the heated object from melting and depositing, depositing or adhering to the furnace wall due to overheating of the heated object, thereby reliably preventing the occurrence of blockage in the furnace. be able to.

  In a preferred embodiment of the present invention, the in-furnace region portion is an in-furnace space between the first and second fuel injection ports and the most advanced position of the flame formed by these fuel injection ports. Preferably, the flow rate ratio or flow rate ratio of the fuel injection amounts of the first and second fuel injection ports is switched and controlled at predetermined time intervals, and the shape, position, and / or temperature distribution in the furnace generated in the furnace are It changes according to the switching operation of the flow rate ratio or flow rate ratio.

From still another aspect, the present invention provides a method for in-furnace combustion in a rotary kiln that prevents the occurrence of dam rings and the like by using the burner device configured as described above. In-furnace obstructions such as dam rings are in-furnace deposits or furnace wall deposits generated by re-synthesis of the objects to be fired after thermal decomposition due to local temperature drop in the firing atmosphere. For example, in a combustion reaction in which lime is pyrolyzed (CaCO ₃ → CaO + CO ₂ ) at a furnace temperature of 800 ° C. to produce a product (CaO), dam rings are produced due to local decrease in furnace temperature. It is considered that it occurs as a result of the reverse reaction that occurs in the carbon atmosphere, that is, the recarbonation reaction (CaO + CO ₂ → CaCO ₃ ).

  The rotary kiln in-furnace combustion method according to the present invention uses the burner device having the above-described configuration to control the flow rate ratio or flow rate ratio of each fuel injection amount of the first and second fuel injection ports to generate in the furnace. This is a furnace combustion method in which the flame shape, position and / or temperature distribution in the furnace is changed over time. According to such an in-furnace combustion method, an object to be pyrolyzed in a firing atmosphere at a predetermined temperature or higher is re-synthesized after thermal decomposition due to a temperature drop in the local firing atmosphere to produce a solidified product in the furnace. Prevents the occurrence of dam rings, etc., thereby reducing the frequency of transient shutdowns to remove obstructions or greatly delaying the shutdown period It becomes.

In a preferred embodiment of the present invention, the object to be heated is thermally decomposed in a high-temperature firing atmosphere to produce lime (CaO) and re-carbonated after pyrolysis due to a temperature drop in the firing atmosphere (CaCO ₃ The switching control of the flow rate ratio or flow rate ratio is set so as not to cause a local temperature drop in order to prevent dam rings from being formed in the furnace due to recalcification of lime.

  In a further preferred embodiment of the present invention, the flow rate ratio or flow rate ratio of the fuel injection amounts of the first and second fuel injection ports is obtained by recombining the material to be fired after thermal decomposition due to a temperature drop in the local firing atmosphere. In order to prevent this, the switching control is performed at predetermined time intervals, and the shape, position and / or temperature distribution in the furnace generated in the furnace are changed with time.

  According to yet another aspect, the present invention provides a method for in-furnace combustion in a rotary kiln in which an object to be heated is fired or pyrolyzed in a high-temperature firing atmosphere using the burner device having the above-described configuration. A method for in-furnace combustion in a rotary kiln characterized by reducing the amount of fuel used by controlling the flow rate ratio or the flow rate ratio of the fuel injection amount is provided.

  According to the rotary kiln burner apparatus and the in-furnace combustion method according to the present invention, the flame generated in the furnace without depending on the setting change of the apparatus structure or the apparatus configuration, without using movable members such as movable blades. The shape, position and / or temperature distribution of the can be set and changed relatively easily.

  Further, according to the in-furnace combustion method of the present invention using the burner device for the rotary kiln, the obstruction in the furnace is removed by suppressing the generation of the obstruction in the furnace by preventing local overheating, temperature drop and the like. Therefore, it is possible to reduce the frequency of the transient operation stop for the purpose or to greatly delay the operation stop time or to reduce the amount of fuel used to save energy in the rotary kiln.

FIG. 1 is a longitudinal sectional view schematically showing the entire configuration of a rotary kiln. FIG. 2 is a longitudinal sectional view showing the structure of the burner device according to the embodiment of the present invention. FIG. 3 is a partially enlarged cross-sectional view of the burner device shown in FIG. FIG. 4 is a front view of the burner device shown in FIGS. 2 and 3. FIG. 5 is a perspective view showing the configuration of the fuel injection port shown in FIGS. FIG. 6 is a partially enlarged sectional view showing a structure of a burner device according to another embodiment of the present invention. FIG. 7 is a front view of the burner device shown in FIG. FIG. 8 is a longitudinal sectional view showing the structure of a burner device according to still another embodiment of the present invention. FIG. 9 is a front view of the burner device shown in FIG. 10A is a partial cross-sectional view of a rotary kiln schematically showing the flame shape and the like in the furnace, and FIGS. 10B and 10C are diagrams illustrating the temperature distribution of the flame temperature. is there. FIG. 11 is a system configuration diagram of a combustion system including the burner device shown in FIGS. 8 and 9 according to the present invention. FIG. 12 is a partial cross-sectional view and a temperature distribution diagram of the rotary kiln showing the in-furnace combustion method of the rotary kiln using the combustion system shown in FIG. 13 is a partial cross-sectional view and a temperature distribution diagram of a rotary kiln showing another in-furnace combustion method of the rotary kiln using the combustion system shown in FIG. FIG. 14 is a time chart illustrating combustion mode switching patterns for the three types of combustion modes for generating various flames shown in FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a longitudinal sectional view schematically showing the entire configuration of a rotary kiln.

  The rotary kiln K is a heating furnace, a firing furnace or an incinerator used for applications such as cement firing, quick lime, lightweight aggregate, ceramic raw material production, or incineration of waste plastic, municipal waste, etc. . At the end of the rotary kiln K, a rotary kiln burner device B (hereinafter referred to as “burner device B”) that generates a flame in the in-furnace region α is disposed. Primary air A1 is supplied to the burner device B as combustion air, and gaseous fuel G such as city gas is supplied to the burner device B. The rotary kiln K rotates the cylindrical iron shell S lined with heat insulating and refractory material around the axis line at a constant speed, and raises the furnace atmosphere to a temperature of, for example, 1400 ° C. by the combustion operation of the burner device B. Let A raw material M such as a cement raw material to be fired is charged into the in-furnace region α of the rotary kiln K from the raw material inlet J located on the side opposite to the burner device B, and is mainly fired in a state where it is deposited on the hearth Kf. Is done. The object to be heated W such as a baked clinker moves or flows along the hearth part Kf to the burner device B side, is led out of the furnace at the end of the burner device B side, and passes outside the system via the cooling device E. To be discharged. External air to be supplied as secondary air A2 to the outer peripheral region of the burner device B is supplied to the cooling device E. The outside air exchanges heat with the article to be heated W ′ discharged from the furnace area of the rotary kiln K, and is supplied to the outer area β of the burner apparatus B as secondary air A2 preheated to 1000 ° C. or higher.

  As shown in FIG. 1, the hearth part Kf of the rotary kiln K extends in the furnace length direction at the lower part of the inner peripheral wall surface of the in-furnace region α. Since the object to be heated W in the in-furnace region α moves or flows along the hearth part Kf to the lower side in the inclination direction of the rotary kiln K, the flame F of the burner device B is the type, physical properties, and manufacture of the object to be heated W. It is desirable to optimize the heating / firing action of the flame F so that the article to be heated W is heated or fired at an optimum temperature and at an optimum position according to the conditions. In the present invention, for example, when the optimum heating temperature T1 is set at the position of the distance L1 from the front end surface of the burner device B for the article W to be heated in the hearth Kf, such positional conditions and temperature conditions are set. The flame position, flame shape, flame length, flame temperature distribution, flame temperature peak position, etc. of the flame F are controlled so as to realize the above.

  FIG. 10A shows flames Fa, Fb, and Fc having different flame positions, flame shapes, flame lengths, and the like. FIG. 10B is a diagram showing the temperature distribution (distance L direction) of the flame temperatures T of the flames Fa, Fb, and Fc measured at the temperature evaluation level Ka. FIG. 10C is a diagram showing a manner of change in flame temperature obtained by changing the air ratio of the combustion reaction with respect to the flame Fc. The temperature evaluation level Ka is set at a position near the furnace wall of the hearth part Kf.

  The flames Fa, Fb, and Fc have a flame surface in which the flame zone is entirely biased to a region near the hearth portion Kf in order to efficiently heat the article W (FIG. 1) of the hearth portion Kf. The temperature distribution of the flames Fa, Fb, Fc changes as shown in FIG. 10B in accordance with the change of the flame length or the flame arrival distance, and the flame temperature peak positions La, Lb, Lc of the flames Fa, Fb, Fc. Also, the burner device B is displaced in the direction of the central axis XX (direction of the distance L) in accordance with the change in the flame length or the flame reach distance.

  Further, regarding the flame Fc, when the amount of combustion air is increased, the maximum flame temperature (peak temperature) rises at substantially the same flame temperature peak position Lc, as shown as flame Fc ′ in FIG. When the amount of combustion air is reduced, the maximum flame temperature (peak temperature) decreases at approximately the same flame temperature peak position Lc, as shown as flame Fc ″ in FIG.

  The burner device B according to the present invention has first and second fuel injection ports that inject gaseous fuel G in different angular directions with respect to the central axis XX, and a flow rate ratio between the first and second fuel injection ports. To change the shape, position and / or temperature distribution of the flame, thereby generating flames with different flame positions, flame shapes, flame lengths, etc. in the in-furnace region α like flames Fa, Fb and Fc. To do. Hereinafter, with reference to FIGS. 2-5, embodiment of the burner apparatus B which concerns on this invention is described.

  2 and 3 are a longitudinal sectional view and a partially enlarged sectional view of the burner device B according to a preferred embodiment of the present invention, and FIG. 4 is a front view of the burner device B shown in FIGS. 2 and 3. . FIG. 5 is a perspective view showing a configuration of a fuel injection port that injects a fuel jet obliquely downward. In addition, the burner apparatus B is arrange | positioned at the edge part of the rotary kiln K, as shown in FIG. FIG. 4 is a front view of the burner apparatus B as viewed from the in-furnace region α of the rotary kiln K.

  The fuel supply system of the burner apparatus B includes fuel supply pipes GP1 and GP2 connected to a supply source or supply pipe (not shown) of a gaseous fuel G such as city gas. On the central axis XX of the burner device B, an auxiliary combustion device 11 having a pilot burner at its tip is arranged. The burner device B includes a first fuel injection port 2 and a second fuel injection port 3 for injecting fuel jets G1 and G2 of gaseous fuel G, and a primary disposed radially outward of the fuel injection ports 2 and 3. An air injection port 4 and a secondary air injection port 5 are provided. The primary air injection port 4 and the secondary air injection port 5 inject the primary air jet A1 and the secondary air jet A2, respectively.

  As shown in FIG. 4, the pair of left and right fuel injection ports 2 are disposed in the upper half of the burner device B, and the pair of left and right fuel injection ports 3 are disposed in the lower half of the burner device B. The fuel injection ports 2 and 3 are arranged at an angular interval of approximately 90 degrees around the central axis XX. As shown in FIG. 3, the fuel injection port 2 has a substantially vertical front end surface, and the fuel injection nozzle 2 a of the fuel injection port 2 makes the fuel jet flow G <b> 1 linearly flow in the direction of the central axis XX. Spray. On the other hand, as shown in FIGS. 3 and 5, the fuel injection port 3 has a tip surface 31 that is inclined at an angle of about 30 to 60 degrees with respect to a vertical surface, and the fuel injection port 3 has a central axis X It is composed of a plurality of fuel injection nozzles 30 inclined in a direction that forms a predetermined inclination angle θ (FIG. 3) with respect to −X. The fuel injection nozzle 30 injects the fuel jet G2 in the direction of the inclination angle θ. That is, the fuel injection nozzle 30 injects the fuel jet G2 obliquely downward toward the hearth part Kf. The angle θ can be preferably set to an angle within a range of 20 to 45 degrees, for example, 30 degrees.

  The burner device B further has air injection ports 6, 7, 8 (hereinafter, referred to as “combustion control air C”) for injecting combustion air C (hereinafter referred to as “combustion control air C”) lower than the fuel jets G 1, G 2 for flame property control. , And “control air injection ports 6, 7, 8”). The control air injection port 6 injects combustion control air C into the furnace from the vicinity of the fuel injection port 2, and the control air injection port 7 starts combustion control air C from an annular zone that entirely surrounds the fuel injection ports 2 and 3. Is injected into the furnace, and the control air injection port 8 injects combustion control air C from the vicinity of the fuel injection port 3 into the furnace. As the combustion control air C, preheated air preheated to a temperature of 100 ° C. or higher (for example, 200 ° C.) may be injected into the furnace. In the present embodiment, the flow rates of the fuel jets G1 and G2 at the fuel injection ports 2 and 3 are set to a flow rate of 100 m / s or more, and the flow rate of the combustion control air C at the control air injection ports 6, 7, and 8 Is set to a flow velocity of less than 100 m / s.

  The primary and secondary air injection ports 4 and 5 inject the primary and secondary air jets A1 and A2 in a direction parallel to the central axis XX, and the control air injection ports 6 and 7 also supply the combustion control air C. Injected in a direction parallel to the central axis XX. On the other hand, the control air injection port 8 injects the combustion control air C in a direction that forms an inclination angle θ with respect to the central axis XX. The primary air jet A1 injected from the primary air injection port 4 flows along the fuel jet G1, and is mainly brought into contact with the gaseous fuel G of the fuel jet G1 to undergo a combustion reaction, and is injected from the control air injection ports 6 and 7. The combustion control air C thus produced also undergoes a combustion reaction mainly in contact with the gaseous fuel G of the fuel jet G1. On the other hand, the combustion control air C injected from the control air injection port 8 flows into the furnace in the same direction (substantially the same direction) as the fuel jet G2, and is attracted by the fuel jet G2 to burn with the gaseous fuel G. While reacting, it flows toward the hearth Kf. The secondary air jet A2 injected from the secondary air injection port 5 into the in-furnace region α is further mixed with the gaseous fuel G and the air-fuel mixture, and mixed with the gaseous fuel G in the air-fuel mixture for combustion. react.

  Thus, a flame F due to the mixed contact between the fuel jets G1, G2 and the air jets A1, A2, C is generated in the in-furnace region α. This flame F is a substantially single flame formed by combining or assembling the flames generated by the combustion reaction of the fuel jets G1, G2 and the air jets A1, A2, C, and its shape, position and / or temperature. The distribution or the like changes in accordance with the flow rate ratio or flow rate ratio of the fuel jets G1 and G2 injected by the fuel injection ports 2 and 3. Therefore, the shape, position and / or temperature distribution of the flame can be changed in a relatively wide range by controlling the flow rate ratio or flow rate ratio of the fuel injection amounts of the fuel injection ports 2 and 3.

  In the present embodiment, the fuel control system that mainly controls the flow ratio of the fuel jets G1 and G2 to control the flame position, flame shape, flame length, flame temperature distribution, peak position, etc. of the flame F is the burner device B. Provided. Hereinafter, the configuration of various pipes and the like of the burner device B and the configuration of the fuel control system will be described with reference to FIGS.

  As shown in FIGS. 2 and 3, the burner device B includes a fuel supply pipe 12 for supplying the fuel jet G1 to the fuel injection port 2 and a fuel supply pipe for supplying the fuel jet G2 to the fuel injection port 3. 13 in the center. The burner device B further includes a primary air supply pipe 14 for supplying primary air to the primary air injection port 4 and a control air supply pipe 15 for supplying combustion control air to the control air injection ports 6 and 7. . The auxiliary combustion device 11 and the fuel supply pipes 12 and 13 are arranged in a primary air supply pipe 14, and the primary air supply pipe 14 is arranged concentrically in a control air supply pipe 15.

  The control air supply pipe 15 constitutes an outer pipe of the burner device B and includes an outer flange portion 17 supported by the end structure of the rotary kiln K. The exterior flange portion 17 is connected to a mounting plate 18 having the secondary air injection port 5, and the mounting plate 18 is connected to a partition wall 19 constituting an end structure of the rotary kiln K. The secondary air A2 supplied to the outer region β of the burner device B flows from the secondary air injection port 5 into the in-furnace region α.

  The burner device B includes a circular distal end plate 20 that closes the distal ends of the primary air supply pipe 14 and the control air supply pipe 15, a circular proximal end plate 21 that closes the proximal end of the control air supply pipe 15, A circular proximal end plate 22 that closes the proximal end of the air supply pipe 14. The primary air supply pipe 14 extends outward through the base end plate 21, and the auxiliary combustion device 11 and the fuel supply pipes 12 and 13 extend outward through the base end plate 22.

  As shown in FIG. 4, the tip plate 20 is provided with a plurality of primary air injection ports 4 and a plurality of control air injection ports 6 and 7. The primary air injection ports 4 are annularly arranged at an angular interval so as to surround the tip of the auxiliary combustion device 11. The control air injection port 6 is opened in an overall semicircular arc shape in the upper half of the tip plate 20, and the control air injection port 7 is angularly spaced so as to entirely surround the fuel injection ports 2 and 3. They are arranged in a ring at a distance. The control air injection port 8 is composed of a tube projecting from the lower part of the control air supply pipe 15, extends obliquely forward and downward, and opens substantially in the vicinity of the lower end portion of the tip plate 20.

  As shown in FIG. 2, the pipe joint portion 14a of the primary air supply pipe 14 is connected to the air supply pipe 24 constituting the primary air supply system P1, and the pipe joint portion 15a of the control air supply pipe 15 is supplied with control air. It is connected to a control air supply pipe 25 constituting the system P2. The primary air supply system P <b> 1 includes a blower 26 that pumps normal temperature air (air at ambient temperature) to the primary air supply pipe 14. The control air supply system P2 supplies preheated air preheated to a temperature of 100 ° C. or higher (for example, about 200 ° C.) to the control air supply pipe 15.

  The burner device B includes a control unit C / U that controls the operation of the blower 26 and also controls the operation of the control air supply system P2. The control unit C / U is connected to the drive unit of the blower 26 via a control signal line (indicated by a one-dot chain line), and controls signals to the blower and the preheating device (not shown) of the control air supply system P2. They are connected via a line (not shown). The control unit C / U is further connected to the flow control valves V1, V2 of the fuel supply pipes GP1, GP2, and controls the flow rate of the gaseous fuel G supplied to the fuel injection port 2 via the fuel supply pipe GP1. While being variably controlled by the valve V1, the flow rate of the gaseous fuel G supplied to the fuel injection port 3 via the fuel supply pipe GP2 is variably controlled by the flow rate control valve V2.

  When the flow control valve V2 is shut off to stop fuel injection at the fuel injection port 3, the flow control valve V1 is opened and the fuel jet G1 is injected from the fuel injection port 2 into the in-furnace region α, as shown in FIG. An elongated flame F extending in the furnace length direction at the center of the furnace area is generated in the furnace area α. When the flow control valve V2 is opened and the fuel jet G2 is further injected from the fuel injection port 3 into the in-furnace region α, the downward momentum of the fuel jet G2 acts on the flame F, and is shown as flame Fc in FIG. As described above, a flame-shaped flame biased toward the hearth side is generated in the in-furnace region α. The flame Fc shown in FIG. 10A is a flame generated in the in-furnace region α in a state where the opening degree of the flow control valve V1 is set to 70% and the opening degree of the flow control valve V2 is set to 30%. .

  When the opening degree of the flow control valve V2 is increased and the flow rate of the fuel jet G2 is relatively increased, the downward momentum of the fuel jet G2 further acts on the flame F, and the flame shaped flame Fb further biased toward the hearth side. Is generated in the in-furnace region α as shown in FIG. A flame Fb shown in FIG. 10A is a flame generated in the in-furnace region α in a state where the opening degree of the flow control valves V1 and V2 is set to 50%. When the opening degree of the flow rate control valve V2 is further increased and the flow rate of the fuel jet G2 is greatly increased, the downward momentum of the fuel jet G2 acts greatly on the flame F, and as shown in FIG. A flame having a relatively large deviation toward the floor is generated in the in-furnace region α. As described above, the temperature distribution of the flame temperature and the flame temperature peak position change in accordance with such a change in the flame shape. Note that the flame Fa shown in FIG. 10A is generated in the in-furnace region α in a state where the opening degree of the flow control valve V1 is set to 0% and the opening degree of the flow control valve V2 is set to 100%. It is.

  Thus, according to the present invention, the fuel injection ports 2 and 3 for injecting the gaseous fuel G in different angular directions with respect to the central axis XX of the burner device B are provided, and the fuel injection amount of the fuel injection ports 2 and 3 is determined. By variably controlling the flow rate ratio, the shape, position and / or temperature distribution of the flame F generated in the in-furnace region α can be changed. According to the burner device B having such a configuration, the shape, position, and position of the flame F generated in the in-furnace region α without changing the setting of the device structure or device configuration, without using a movable member such as a movable blade, and the like. It is possible to change the setting of the temperature distribution relatively easily. Moreover, the control of the flame shape, position and / or temperature distribution can be changed during the combustion operation or operation of the burner device B by means of the control unit C / U and the flow control valves V1, V2, which is very advantageous. is there.

  Further, according to the present invention, the combustion control air C, which is slower than the fuel jets G1 and G2, is injected along the fuel jets G1 and G2 into the in-furnace region α and is attracted to the fuel jets G1 and G2. Since the air of the air C is mixed and contacted with the fuel to cause a combustion reaction, the combustion stability of the in-furnace combustion reaction is improved.

  If desired, a flow rate control means for variably controlling the flow rate of the combustion control air C is further provided, and the mixing ratio or the mixing process of the fuel jet and the combustion air jet is changed by the flow rate control of the combustion control air C, and the flame formation position, flame The temperature distribution or the flame temperature peak position may be changed.

  Preferably, premixing means for premixing combustion air with gaseous fuel G is provided in the fuel injection nozzles 2a, 30. According to such a configuration, the burner device B can further variably control the flame temperature peak position and the like by changing the premixing ratio of the air and the gaseous fuel G by the premixing means.

  More preferably, the fuel injection nozzles 2a and 30 are provided with swirl vanes for supplying the fuel jet as a swirl flow into the furnace. According to such a configuration, the burner device B supplies the fuel jets G1 and G2 as swirling flows into the furnace. The swirl flow fuel jets G1 and G2 effectively attract the surrounding air, thereby facilitating the mixing of fuel and air.

  6 and 7 are a partially enlarged sectional view and a front view of a burner device according to a modification of the burner device. 6 and 7, the same reference numerals are assigned to components or components that are substantially the same as or equivalent to the components or components shown in FIGS. 2 to 6.

  The burner device B shown in FIGS. 6 and 7 has a large number of control air injection ports 8 arranged at the lower part of the tip plate 20. Each injection port 8 is composed of a short tube having a circular cross section that penetrates the tip plate 20 in a direction that forms an inclination angle θ with respect to the central axis XX.

  8 and 9 are a longitudinal sectional view and a front view of a burner device according to another embodiment of the present invention. 8 and 9 are a partially enlarged sectional view and a partially enlarged front view of the burner tip. 8 and 9, the same reference numerals are assigned to components or components that are substantially the same as or equivalent to the components or components of the above-described embodiment.

  The burner apparatus B shown in FIG.8 and FIG.9 divides | segments the internal space of the air supply pipe | tube 14 into the primary air supply system P1, and divides | segments the upper half part into the primary air supply system P1 substantially horizontally by the horizontal partition plate 50, and the lower half And a primary air injection port 4 in the upper half and a control air injection port 7 in the lower half.

  As shown in FIG. 9, the primary air injection ports 4 open to the tip plate 20 in an arch shape, a semicircle shape, or a partial circle shape. A plurality (three in this example) of fuel injection ports 2 pass through the opening area of the primary air injection port 4. The position of each fuel injection port 2 can be changed within the range of the opening area of the primary air injection port 4. A number of control air injection ports 7 are distributed in the lower half of the tip plate 20. Each control air injection port 7 opens to the tip plate 20 in the form of a slit extending in the horizontal direction. A plurality (three in this example) of fuel injection ports 3 are arranged in the lower half of the tip plate 20. Each fuel injection port 3 is disposed so as to be surrounded by the control air injection port 7. The primary air injection port 4 injects an air jet in a direction parallel to the central axis XX, and the control air injection port 7 injects an air jet in a direction that forms an inclination angle θ with respect to the central axis XX. .

  8 and 9, reference numerals 52 and 53 are refractory materials, and reference numeral 51 is an arcuate baffle plate disposed in the primary air flow path. 8 and 9, the air supply pipes 24 and 25 of the air supply systems P1 and P2 are connected to the blower 26. Other configurations are substantially the same as or equivalent to those of the above-described embodiment, and thus redundant description is omitted.

  As a modification of the burner device shown in FIGS. 8 and 9, an air flow control valve that operates under the control of the control unit C / U is provided in the primary air supply system P1 and the control air supply system P2, respectively, and primary air injection is performed. The flow rate ratio or flow rate ratio of the air injection amount of the port 4 and the control air injection port 7 may be changed under the control of the control unit C / U. Thus, by variably controlling the flow rate ratio or flow rate ratio of the air injection amount, it is possible to further change the furnace temperature distribution or finely adjust the furnace temperature distribution. The primary air injection port 4 constitutes the first air injection port described above, and the control air injection port 7 constitutes the second air injection port described above.

  FIG. 11 is a system configuration diagram of a combustion system including the burner device shown in FIGS. 8 and 9. 12 and 13 are a partial cross-sectional view and a temperature distribution diagram of the rotary kiln showing the in-furnace combustion method of the rotary kiln K using the combustion system shown in FIG. FIG. 12 shows an in-furnace combustion method for preventing in-furnace blockage caused by overheating of an object to be heated in the vicinity of the fuel injection ports 2 and 3, and FIG. 13 shows a furnace caused by a dam ring. An in-furnace combustion method for preventing internal blockage is shown.

  The combustion system shown in FIG. 11 has a fuel supply system line G0 connected to a gaseous fuel supply source GS. Pipe line G0 is connected to the inflow port of fuel three-way valve SV1. A safety shut-off valve FV is interposed in the pipe line G0. Each outflow port of the three-way valve SV1 is connected to the fuel supply pipes GP1 and GP2, respectively, and selectively supplies the gaseous fuel G to one or both of the fuel supply pipes GP1 and GP2. Further, the combustion system shown in FIG. The upstream end of the air supply system pipeline P0 is connected to the blower 26, and the downstream end of the pipeline P0 is connected to the inflow port of the three-way valve SV2. Each outflow port of the three-way valve SV2 is connected to the primary air supply system P1 and the control air supply system P2, respectively, and selectively supplies combustion air to one or both of the primary air supply system P1 and the control air supply system P2. To do. The three-way valves SV1 and SV2 have a drive unit that switches and controls the valve body position. The drive unit is connected to the control unit C / U via the drive control unit U1.

  Flow control valves V1 and V2 are interposed in the fuel supply pipes GP1 and GP2. Flow control valves V3 and V4 are interposed in the air supply pipes 24 and 25 of the air supply systems P1 and P2. The flow control valves V1, V2, V3, and V4 are, for example, butterfly valves that can adjust the flow rate, and have a drive unit that variably controls the valve body position. The drive unit is connected to the control unit C / U via the drive control units U2 and U3.

(1) In-furnace combustion method to prevent blockage in the furnace due to overheating

  In general, in the rotary kiln K, it is known that a phenomenon in which an object to be heated is overheated easily occurs in a region in the furnace near the fuel injection port of the burner device B. When the object to be heated is melted by overheating and adheres to the furnace wall surface or the hearth part, and grows or expands into a relatively large molten deposit or melted deposit, FIG. ) As illustrated as Cm1, since the in-furnace region α is at least partially blocked or constricted, the operation or operation of the rotary kiln K must be stopped for a certain period in order to remove the plug Cm1. If it is possible to avoid such obstruction removal work, or to reduce the frequency of the removal work or postpone the time of the removal work, it is extremely practically advantageous.

  On the other hand, according to the combustion system including the burner device B having the above-described configuration, the fuel injection port 2, so that the shape, position and / or temperature distribution in the furnace generated in the furnace varies with time. 3 to variably control the flow rate ratio or flow rate ratio of the fuel injection amount, thereby preventing or suppressing overheating of the object to be heated. The phenomenon of melting by heating can be prevented or suppressed, and blockage in the furnace due to the growth or expansion of the molten deposit or molten deposit on the furnace wall surface or the furnace floor can be prevented or avoided. Hereinafter, this furnace combustion method will be described.

  The burner device B includes a straight flame-only firing mode for generating a flame Fa shown in FIG. 12A, a downward flame-only firing mode for generating a flame Fb shown in FIG. 12A, and a flame Fcs shown in FIG. , Operated in three forms, a downward flame co-firing mode to produce Fcd. That is, the flame Fa is a flame generated in the in-furnace region α in the straight flame-only firing mode, the flame Fb is a flame generated in the furnace region α in the downward-flame dedicated firing mode, and the flames Fcs and Fcd are the downward flames. It is a flame produced | generated in the furnace area | region (alpha) in mixed combustion mode. In this example, the fuel flow rate (total value) of the fuel injection ports 2 and 3 in each operation mode is constant. However, the fuel flow rate (total value) of the fuel injection ports 2 and 3 can be made different in each operation mode. Moreover, in this example, the air flow rate (total value) of the air injection ports 4 and 7 in each operation mode is constant. However, the air flow rate (total value) of the air injection ports 4 and 7 can be made different in each operation mode.

  FIG. 12B shows the furnace temperature distribution at the time of generating the flames Fa, Fb, Fcs, and Fcd measured at the temperature evaluation level Ka. The furnace temperature distribution at the time of generation of the flame Fc shown in FIG. 12B is the furnace temperature distribution (temperature at the temperature evaluation level Ka) at the time of generation of the flame Fc obtained by synthesizing the flames Fcs and Fcd. Flames Fa, Fb, and Fc (Fcs, Fcd) are flames having different flame shapes, peak temperature positions La, Lb, and Lc, and peak temperatures Ta, Tb, and Tc. Hereinafter, the above three types of operation will be described.

(A) Straight flame mode

  In the straight flame only firing mode, the three-way valve SV1 feeds the entire amount of the gaseous fuel G to the fuel supply pipe GP1, closes the outflow port on the fuel supply pipe GP2 side, and shuts off the fuel supply flow path. The three-way valve SV2 feeds the entire amount of combustion air to the primary air supply system P1 (air supply pipe 24), closes the outflow port on the control air supply system P2 (air supply pipe 25) side, and the air flow Block the road. The burner device B operates in the form of exclusive combustion of the first fuel injection port 2, and the first fuel injection port 2 injects the fuel jet G1 in a direction parallel to the central axis XX, and the primary air injection port 4 performs the primary operation. The air jet A1 is jetted to generate a flame Fa in the furnace region α. The straight flame combustion mode is an operation mode at low load that is adopted when the heat load is small or the production amount is relatively small, and the peak temperature in the furnace is set to a relatively low temperature (temperature Ta). Is set.

(B) Downward flame-only firing mode

  In the downward flame-only firing mode, the three-way valve SV1 feeds the entire amount of the gaseous fuel G to the fuel supply pipe GP2, closes the outflow port on the fuel supply pipe GP1 side, and shuts off the fuel supply flow path. The three-way valve SV2 feeds the entire amount of combustion air to the control air supply system P2 (air supply pipe 25), closes the outflow port on the primary air supply system P1 (air supply pipe 24) side, and the air flow Block the road. The burner device B operates in the exclusive form of the second fuel injection port 3 and injects the fuel jet G1 in the direction of angle θ through the second fuel injection port 3 and the control air jet C through the angle θ through the control air injection port 7. The flame Fb is generated in the in-furnace region α. The downward flame-only firing mode is an operation mode at a high load that is adopted when the heat load is large or the production amount is relatively large, and the peak temperature in the furnace is set to a relatively high temperature (temperature Tb). Is set.

(C) Downward flame co-firing mode

  In the downward flame mixed combustion mode, the three-way valve SV1 feeds the gaseous fuel G to both the fuel supply pipes GP1 and GP2, and the three-way valve SV2 controls the combustion air to the primary air supply system P1 (air supply pipe 24) and control. It feeds to both air supply systems P2 (air supply pipe 25). The burner device B injects the fuel jet G2 in the direction of angle θ through the second fuel injection port 3, and injects the control air jet C in the direction of angle θ through the control air injection port 7, and causes the flame Fcd to enter the in-furnace region α. Generate. In addition, the burner device B injects the fuel jet G1 in the direction parallel to the central axis XX through the first fuel injection port 2, and also jets the primary air jet A1 through the primary air injection port 4, and the flame Fcs is removed from the furnace. Generated in the inner region α. The in-furnace peak temperature Tc of the flame Fc synthesized from the flames Fcs and Fcd is set to a temperature (intermediate value) that is higher than the in-furnace peak temperature Ta of the flame Fa and lower than the in-furnace peak temperature Tb of the flame Fb. The downward flame mixed combustion mode is an operation mode in which the peak temperature in the furnace can be changed by changing the fuel flow rate ratio of the fuel injection ports 2 and 3, and this combustion mode has a relatively frequent production amount or heat load. It can be suitably used in an operation mode in which the peak temperature in the furnace is adjusted relatively frequently.

  In the in-furnace combustion method of this example, these three types of operation modes are switched and controlled at predetermined time intervals, and the flame shape, position, and in-furnace temperature distribution change with time. FIG. 14 is a time chart showing the switching patterns I to VI of the operation mode. If desired, switching control based on a predetermined furnace speed of the rotary kiln K may be adopted instead of switching control based on the time interval.

  FIG. 14 illustrates combustion patterns I to VI as switching methods of the combustion modes of the straight flame exclusive combustion mode, the downward flame exclusive combustion mode, and the downward flame mixed combustion mode. For example, in the combustion pattern II, the combustion mode is switched in the order of the straight flame exclusive combustion mode → the downward flame exclusive combustion mode → the downward flame mixed combustion mode. In the combustion pattern VI, the combustion mode alternates between the downward flame exclusive combustion mode and the downward flame mixed combustion mode. Is switched to. Each combustion mode is maintained for each time interval of time 1 to 10, but each time interval (that is, switching time) is set to a time of 1 hour or more, for example, a predetermined time ( For example, it may be set to several hours), or may be set to several days or weeks according to the operating conditions.

  In this way, by switching the combustion mode at a predetermined time interval, the flame shape of the in-furnace region α, the peak temperature positions La, Lb, Lc and the peak temperatures Ta, Tb, Tc are changed, and the object to be heated is overheated. Can be prevented or suppressed. By preventing overheating in this way, it is possible to prevent the growth or expansion of molten deposits or molten deposits on the furnace wall or hearth, and reliably prevent or avoid clogging in the furnace caused by this. it can. For example, according to such combustion mode switching control, a relatively small amount and a thin deposit are only generated on the furnace wall surface or the hearth as exemplified by the deposit Cm2 in FIG.

(2) In-furnace combustion method of rotary kiln to prevent the occurrence of dam rings, etc.

As a cause of the blockage of the rotary kiln K, a dam ring generated in the in-furnace region is known. Dam rings are furnace deposits or furnace wall deposits produced by resynthesis of the fired products after thermal decomposition due to local temperature drop in the firing atmosphere. For example, dam rings are pyrolyzed at a furnace temperature of 800 ° C. In a combustion reaction that produces a product (CaO) by (CaCO ₃ → CaO + CO ₂ ), a re-carbonation reaction (CaO + CO ₂ → CaCO ₃ ) that occurs in a carbon dioxide atmosphere due to a local decrease in the furnace temperature, etc. It is thought to occur as a result. When the lime particles generated by the re-carbonation reaction are combined and adhered and deposited as a solidified product on the furnace wall surface or the hearth, a dam ring exemplified as an obstruction (excessive deposit) Dm1 is formed in FIG. Since the in-furnace region α is at least partially blocked or narrowed, the operation or operation of the rotary kiln K has to be stopped for a certain period in order to remove the plug Dm1. If it is possible to avoid such obstruction removal work, or to reduce the frequency of the removal work or postpone the time of the removal work, it is extremely practically advantageous.

  On the other hand, according to the combustion system including the burner device B having the above-described configuration, the fuel injection port 2, so that the shape, position and / or temperature distribution in the furnace generated in the furnace varies with time. 3 variably controlling the flow rate ratio or flow rate ratio of the fuel injection amount to prevent or suppress a temperature drop in the local firing atmosphere, thereby causing the furnace wall surface or the hearth part to originate from the re-carbonization reaction. It is possible to prevent or avoid the formation of solidified material or adhesion / deposition. Hereinafter, this furnace combustion method will be described.

  The burner device B is shown in FIG. 13 (A), which is a straight flame exclusive combustion mode for generating a flame Fa, a first downward flame exclusive combustion mode for generating a flame Fb shown in FIG. 13 (A), and FIG. 13 (A). It operates in three forms: a second downward flame-only firing mode that produces a flame Fc. In each combustion mode, the air ratio of the supply air of the air injection ports 4 and 7 to the fuel flow rate (total value) of the fuel injection ports 2 and 3 is set to a constant value (fixed value). However, the air ratio of the supply air (total value) of the air injection ports 4 and 7 can be variably controlled.

  FIG. 13B shows the furnace temperature distribution when the flames Fa, Fb, and Fc are measured at the temperature evaluation level Ka. The flames Fa, Fb, and Fc are flames having different flame shapes, peak temperature positions La, Lb, and Lc and peak temperatures Ta, Tb, and Tc.

  The straight flame only firing mode of this example is substantially the same operation mode as the straight flame exclusive firing mode described in “In-furnace combustion method for preventing blockage in furnace due to overheating”, and forms flame Fa. The first and second downward flame exclusive firing modes of this example are basically the same operation mode as the downward flame exclusive combustion mode described in “In-furnace combustion method for preventing blockage in furnace due to overheating”, and flame Fb , Form Fc. However, the fuel flow rate at the fuel injection port 3 in the second downward flame-only firing mode is lower than the fuel flow rate at the fuel injection port 3 in the first downward flame-only firing mode, and the peak temperature Tc is equal to the peak temperature Ta. Can be lowered.

  FIG. 13 shows a region γ between the positions L1 and L2 as a portion of the in-furnace region where the obstruction Dm1 is easily generated. If the furnace temperature is locally reduced in this region γ, there is a tendency that a blockage Dm1 (dam ring) is formed by the recarbonation reaction. For this reason, the fuel flow rate of the fuel injection ports 2 and 3 of the burner device B is such that the flame Fa in the straight flame exclusive firing mode forms a firing atmosphere at the furnace temperature T1 at the position L2, and the flame Fc in the second downward flame exclusive firing mode is A firing atmosphere at the furnace temperature T1 is formed at the position L1, and the flame Fb in the first downward flame-only firing mode is set to form a firing atmosphere at the furnace temperature T1 between the positions L1 and L2. The furnace temperature T1 is higher than the temperature at which the recarbonation reaction occurs (the temperature at which the recarbonation reaction does not occur).

The combustion modes of the straight flame mode and the first and second downward flame modes are switched at predetermined time intervals as shown in the combustion pattern II (FIG. 14), for example, and the temperature of the region γ is extremely lowered. And leveling out to a temperature range in the vicinity of the furnace temperature T1. For this reason, the phenomenon of adhesion / deposition and growth / expansion due to the re-carbonation reaction (CaO + CO ₂ → CaCO ₃ ) is unlikely to occur in the region γ, and as illustrated in FIG. 13 (A) as the deposit Dm2. Only a relatively small amount of thin deposits are generated on the furnace wall or the hearth.

  Thus, according to the in-furnace combustion method of the present example, the fuel injection amount of the fuel injection ports 2 and 3 is controlled so that the shape, position and / or temperature distribution in the furnace generated in the furnace fluctuate with time. By variably controlling the flow rate ratio or flow rate ratio, the furnace temperature in the region γ is leveled to prevent or suppress the temperature drop in the local firing atmosphere, thereby preventing the formation of furnace interiors such as dam rings. Or can be avoided.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the above-described embodiments, and various modifications or changes can be made within the scope of the present invention described in the claims. It goes without saying that it is possible.

  For example, the specific arrangement, structure, dimensions, and the like of the air injection port and the fuel injection port can be appropriately changed according to the technique of the present invention.

  Moreover, although the said embodiment is a thing using the gaseous fuel as a fuel, as a fuel, pulverized solid fuels, such as pulverized coal fuel and oil coke, or a liquid spray fuel of a droplet or mist form, etc. are used. You may do it.

  Further, in the above embodiment, the first fuel injection port is configured to inject the first fuel jet in the direction of the central axis of the burner device, but the first fuel injection port is oriented inwardly, thereby , Orienting the central axis of the first fuel jet in the direction of approaching the central axis of the burner device in the jet direction, or mutually aligning the central axes of the first fuel jets injected by the first fuel injection ports in the jet direction You may orient so that it may approach.

  In addition, for the second fuel injection ports, the injection directions of the second fuel injection ports may be oriented so that the central axes of the second fuel jets injected by the second fuel injection ports are close to each other in the jet direction. Is possible.

  Furthermore, in the above embodiment, the central axis of the air jet of each air injection port is oriented in a direction parallel to the central axis of the fuel jet of the adjacent or related fuel injection port, but the central axis of the air jet However, the central axis of the air injection port may be oriented so as to approach the central axis of the fuel jet in the jet direction.

  The in-furnace combustion method according to the above embodiment is configured to sequentially execute a plurality of combustion modes under automatic control in accordance with a preset combustion pattern, but the plurality of combustion modes are manually operated. It can also be carried out sequentially.

  The present invention is applied to a burner device for a rotary kiln and a furnace combustion method for the rotary kiln. According to the present invention, the flame generated in the furnace without depending on the setting change of the apparatus structure or the apparatus configuration of the burner apparatus, without disposing a movable member such as a movable blade as an airflow changing means in the burner apparatus. The shape, position and / or temperature distribution of the can be set and changed relatively easily. Moreover, according to the present invention, since the flame shape and the like can be variably controlled even during operation or operation of the burner device, its practical effect is remarkable.

  Moreover, according to the in-furnace combustion method using the burner device for a rotary kiln according to the present invention, local overheating, temperature drop, or the like that causes the in-furnace blockage is prevented, thereby suppressing the generation of the blockage in the furnace. In this sense, the practical effect of the present invention is remarkable because the problem of transient shutdown for removing the blockage in the furnace can be solved, or the shutdown timing can be greatly delayed. There is.

DESCRIPTION OF SYMBOLS 1 Burner apparatus for rotary kilns 2 1st fuel injection port 3 2nd fuel injection port 4 Primary air injection port 5 Secondary air injection port 6, 7, 8 Control air injection port 20 Tip plate 30 Fuel injection nozzle 31 Tip surface A1 Primary air ,
A2 Secondary air B Burner device C Combustion control air C / U Control unit F Flame G Gaseous fuel G1, G2 Fuel jet K Rotary kiln Kf Hearth V1, V2 Flow control valve X Central axis α Furnace region θ Inclination angle

Claims (15)

A fuel injection port for injecting fuel, and an air injection port disposed radially outward of the fuel injection port, and by a mixed contact between the fuel jet of the fuel injection port and the air jet of the air injection port In the rotary kiln burner device that generates a flame in the rotary kiln furnace,
The fuel injection port includes first and second fuel injection ports that inject the fuel in different angular directions with respect to the central axis of the burner device, and the fuel injection amount of the first and second fuel injection ports. A control device for controlling the flow rate ratio or flow rate ratio is provided.
The first fuel jet injected from the first fuel injection port has a central axis substantially parallel to the central axis of the burner device, or in a direction approaching the central axis of the burner device in the jet direction. Having a central axis extending;
The second fuel injection port injects the second fuel jet in a direction that forms a predetermined inclination angle with respect to the central axis of the first fuel jet,
The rotary kiln burner apparatus characterized in that the first and second fuel injection ports change the shape, position and / or temperature distribution of the furnace generated in the furnace by changing the flow rate ratio or flow rate ratio.   The second fuel injection port is composed of a fuel injection nozzle disposed on a front end surface of a fuel supply pipe, and the fuel injection nozzle injects a fuel jet obliquely downward toward the hearth portion. Item 10. A rotary kiln burner device according to Item 1.   The rotary kiln burner apparatus according to claim 1 or 2, further comprising premixing means for premixing combustion air with the fuel.   The central axis of the air jet of the air jet is oriented in a direction substantially parallel to the central axis of the fuel jet of the adjacent or related fuel jet, or the central axis of the air jet of the air jet 4. The rotary kiln burner device according to claim 1, wherein the burner device is oriented so as to approach a central axis of the fuel jet in the jet direction. 5. A fuel jet of fuel is injected from the fuel injection port, and an air jet is injected from an air injection port arranged radially outward of the fuel injection port. By mixing contact of the fuel jet and the air jet, the rotary kiln In the in-furnace combustion method of a rotary kiln that generates a flame in the furnace,
The fuel injection port is constituted by first and second fuel injection ports that inject the fuel in different angular directions with respect to the central axis of the burner device,
The first fuel injection port has a center axis that is substantially parallel to the center axis of the burner device, or a first axis that extends in a direction approaching the center axis of the burner device in the jet direction. A fuel jet is injected, and the second fuel injection port injects the second fuel jet in a direction that forms a predetermined inclination angle with respect to the central axis of the first fuel jet,
By controlling the flow rate ratio or the flow rate ratio of the fuel injection amounts of the first and second fuel injection ports, the direction of fuel jet diffusion and the mixing ratio or mixing process of fuel and air are changed, so that A method for in-furnace combustion in a rotary kiln, wherein the shape, position and / or temperature distribution in the furnace is changed.   The second fuel injection port is composed of a fuel injection nozzle disposed on a front end surface of a fuel supply pipe, and the fuel injection nozzle injects a fuel jet obliquely downward toward the hearth portion. Item 6. The in-furnace combustion method according to Item 5.   The in-furnace combustion method according to claim 5 or 6, wherein the flame temperature peak position is changed by premixing combustion air with the fuel and changing the premixing ratio.   The central axis of the air jet of the air jet is oriented in a direction substantially parallel to the central axis of the fuel jet of the adjacent or related fuel jet, or the central axis of the air jet of the air jet The in-furnace combustion method according to any one of claims 5 to 7, characterized in that is oriented so as to approach the central axis of the fuel jet in the jet direction.   5. The apparatus according to claim 1, further comprising: a plurality of first fuel injection ports that simultaneously inject a first fuel jet, and a plurality of second fuel injection ports that inject a second fuel jet simultaneously. The burner device for a rotary kiln described in 1.   The first fuel jet is simultaneously injected from the plurality of first fuel injection ports, and the second fuel jet is simultaneously injected from the plurality of second fuel injection ports. The furnace combustion method as described.   The air injection port includes first and second air injection ports for injecting the air jet in different angular directions with respect to the central axis of the burner device, and the air injection amount of the first and second air injection ports The rotary kiln burner device according to any one of claims 1 to 4 or 9, wherein a flow rate ratio or a flow rate ratio is controlled by the control device.   The first and second air injection ports that inject the air jet in different angular directions with respect to the central axis of the burner device constitute the air injection port, and the air injection amount of the first and second air injection ports The furnace combustion method according to any one of claims 5 to 8, wherein the furnace temperature distribution is changed by controlling a flow rate ratio or a flow rate ratio. In the in-furnace combustion method of a rotary kiln which uses a burner device according to any one of claims 1 to 4, 9, or 11 to fire an object to be heated in a high temperature firing atmosphere.
In order to prevent the object to be heated from being overheated and melted by the flame of the burner device in the region in the furnace near the first and second fuel injection ports of the burner device, the first and second fuels A method for in-furnace combustion in a rotary kiln characterized by controlling a flow rate ratio or a flow rate ratio of a fuel injection amount at an injection port and changing a shape, a position and / or a temperature distribution in the furnace over time. . In the in-furnace combustion method of a rotary kiln in which the object to be heated is thermally decomposed in a high-temperature firing atmosphere using the burner device according to any one of claims 1 to 4, 9, or 11.
The object to be heated is thermally decomposed in a firing atmosphere at a predetermined temperature or higher, and recombined after thermal decomposition due to a temperature drop in the local firing atmosphere to generate a solidified product in the furnace. In order to prevent recombination of the baked material after thermal decomposition due to a temperature drop in the calcination atmosphere, the flow rate ratio or flow rate ratio of the first and second fuel injection ports and the fuel injection amount are controlled and generated in the furnace. A method for in-furnace combustion in a rotary kiln, characterized in that the shape, position and / or temperature distribution in the furnace is varied over time. In the in-furnace combustion method of a rotary kiln in which an object to be heated is fired or pyrolyzed in a high-temperature firing atmosphere using the burner device according to any one of claims 1 to 4, 9, or 11.
A rotary kiln in-furnace combustion method characterized in that energy saving is achieved by controlling the flow rate ratio or flow rate ratio of the fuel injection amounts of the first and second fuel injection ports to reduce the amount of fuel used.

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