JP5942499B2 - burner - Google Patents

Description

  The present invention relates to a burner.

  As a burner including a fuel injection nozzle that injects fuel into a combustion chamber where an airflow is formed along a wall surface, for example, a heat storage burner described in Patent Document 1 is known. This heat storage type burner has a fuel injection nozzle provided in the center of the main body and a pair of flow paths provided with heat storage bodies provided on both sides thereof. The pair of flow paths are configured to be able to alternately switch the air flow, and the fuel is continuously injected from the fuel injection nozzle, or is configured to be injected / interrupted according to the timing of the air switching. It has become.

  When the air is supplied from one flow path, the combustion exhaust gas in the combustion chamber is sucked into the other flow path and exhausted after heating the heat storage body. Conversely, when air is supplied from the other flow path, the combustion exhaust gas is sucked into one flow path and heated after the heat storage body is exhausted. In such a regenerative burner, a large air flow is generated along the wall surface of the combustion chamber by supplying and exhausting air through a pair of flow paths, and the hot gas is turned to the vicinity of the fuel injection nozzle provided on the wall surface, thereby producing fuel. Heat is applied to stabilize the flame.

JP-A-9-89242

However, at the time of so-called cold start until the temperature of the combustion chamber rises to a predetermined temperature, the temperature of the airflow flowing along the wall surface of the combustion chamber is low, so that the heat that can be given to the fuel injected from the fuel injection nozzle is small The flame becomes unstable. Furthermore, there is a problem of misfire that the unstable flame is frequently blown out by the large flow of the air flow.
Note that this misfire problem may occur not only in a heat storage type burner at the time of cold start but also in a burner that injects low-calorie fuel, for example.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a burner capable of stable combustion even in a flow field where an air flow is formed along the wall surface of the combustion chamber.

  In order to solve the above problems, the present invention provides a burner including a fuel injection nozzle that injects fuel into a combustion chamber in which an airflow is formed along a wall surface, the burner being spaced from the wall surface to the combustion chamber. Between the groove portion forming the auxiliary combustion chamber recessed into the first combustion position, the first injection position protruding into the combustion chamber to inject the fuel, and the second injection position intruding into the auxiliary combustion chamber and injecting the fuel. And a moving device for moving the fuel injection nozzle.

  Moreover, in this invention, the said groove part employ | adopts the structure that a circulating flow is formed in the said auxiliary combustion chamber by the said airflow.

  Moreover, in this invention, the structure that the said groove part is extended in the downstream in the flow direction of the said airflow with respect to the said fuel-injection nozzle is employ | adopted.

  Moreover, in this invention, the said fuel injection nozzle employ | adopts the structure that it has the auxiliary fuel injection opening opened to a side.

  Further, in the present invention, a configuration is adopted in which the auxiliary fuel injection port is disposed obliquely with respect to the side wall of the groove when at least the second injection position is located.

  In the present invention, a configuration is adopted in which a control device that controls the driving of the moving device according to the temperature of the combustion chamber is provided.

  Further, in the present invention, a heat accumulator is provided and a pair of flow paths connected to the combustion chamber are provided. When gas is supplied from the one flow path to the combustion chamber, A configuration is adopted in which a heat storage device that forms the air flow by sucking the gas in the combustion chamber is used.

According to the present invention, it is possible to form an auxiliary combustion chamber that becomes a low flow velocity flow field with a low flow velocity deviated from the main flow of the air flow in the combustion chamber by the groove portion. Therefore, normal diffusion combustion in the combustion chamber is possible when the fuel injection nozzle is located at the first injection position, and in a flow field with a low flow velocity in the auxiliary combustion chamber when the fuel injection nozzle is located at the second injection position. Stable partial premix combustion is possible.
In the present invention, by making the fuel injection position variable in this way, switching between diffusion combustion and partial premixed combustion becomes possible, and a mixture of fuel and air that matches the temperature and flow velocity of the airflow is formed. Thus, stable combustion is possible even in a flow field in which an airflow is formed along the wall surface of the combustion chamber.

It is a general view which shows the structure of the thermal storage type burner in embodiment of this invention. It is arrow XX sectional drawing in FIG. FIG. 3 is a cross-sectional view taken along line YY in FIG. 2. It is a figure which shows the mode of combustion according to the position of the fuel injection nozzle in embodiment of this invention. It is sectional drawing which shows the structure of the fuel-injection nozzle in 2nd Embodiment of this invention. It is a figure which shows the mode of the circulation flow in the groove part in 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, a heat storage type burner is illustrated as the burner of the present invention.

(First embodiment)
FIG. 1 is an overall view showing a configuration of a regenerative burner 1 in an embodiment of the present invention. 2 is a cross-sectional view taken along the line XX in FIG. 3 is a cross-sectional view taken along the line YY in FIG.
As shown in FIG. 1, the heat storage burner 1 is a hermetic burner that burns in a combustion chamber R sealed by a shell 2 and heats an object placed outside by radiant heat via the shell 2. For example, it is provided in a heating furnace that heats a metal or the like in an oxygen-free atmosphere.

  The shell 2 is a part that surrounds the combustion chamber R and is heated by generating combustion gas therein. As shown in FIG. 2, the shell 2 has a shape with a flat cross section. Moreover, as shown in FIG. 1, the shell 2 has a bottomed cylindrical shape, and the bottom is smoothly curved. Inside the shell 2, a partition plate 4 that forms the wall surface 3 of the combustion chamber R together with the shell 2 is provided.

  The partition plate 4 is provided with a vent hole 5. Two ventilation holes 5 penetrate in the thickness direction of the partition plate 4, and are provided on the left and right sides of the shell 2. The vent 5 is configured to connect the combustion chamber R and the pair of flow paths 6. Two pairs of flow paths 6 are provided on the left and right sides of the shell 2 corresponding to the vent holes 5. The pair of flow paths 6 are independent from each other, and are configured so that the internal gas is not mixed.

A heat storage body 7 is arranged inside the pair of flow paths 6. The heat storage body 7 stores the heat of the combustion gas and preheats an oxidant such as air with the heat. As the heat storage body 7, for example, a form in which ceramics are meshed, a form in which ceramic balls are filled, a form in which ceramics are formed in a honeycomb shape, or the like is employed.
The heat storage burner 1 includes a gas supply / exhaust device (heat storage device) 8. The gas supply / exhaust device 8 includes a switching valve 8 a controlled by the control device 9, and the air flow in the combustion chamber R is switched by switching the connection state between an unillustrated air pump or exhaust pump and the pair of flow paths 6. It is comprised so that the flow direction of G can be changed.

When supplying gas (air) which becomes an oxidant from the flow path 6A (one flow path) to the combustion chamber R, the gas (combustion gas) in the combustion chamber R is sucked in the flow path 6B (the other flow path), Thereby, an air flow G (shown by a solid line) is formed along the wall surface 3 of the combustion chamber R.
On the other hand, when the gas serving as the oxidant is supplied from the flow path 6B to the combustion chamber R, the gas in the combustion chamber R is sucked in the flow path 6A, and thereby the reverse direction along the wall surface 3 of the combustion chamber R. An air flow G (indicated by a broken line) is formed.

  The regenerative burner 1 has a fuel injection nozzle 10. The fuel injection nozzle 10 injects fuel (gas fuel in the present embodiment) from a fuel injection port 10a at the tip into a combustion chamber R in which an airflow G is formed along the wall surface 3. The fuel injection nozzle 10 is disposed in a through hole 11 formed in the center of the partition plate 4. In the present embodiment, a gap is formed between the fuel injection nozzle 10 and the through-hole 11, and pilot air for ignition is supplied through this gap. An ignition device (not shown) is provided in the vicinity of the fuel injection nozzle 10.

  The regenerative burner 1 has a groove 12 as shown in FIG. The groove 12 forms an auxiliary combustion chamber R1 that is recessed from the wall surface 3 to the side away from the combustion chamber R. The groove 12 is formed in the partition plate 4. A through-hole 11 is disposed at the bottom of the groove 12. The groove 12 is formed around the fuel injection nozzle 10. As shown in FIG. 2, the groove portion 12 of the present embodiment is formed in a rectangular shape as viewed from the fuel injection direction. As shown in FIG. 3, the groove 12 forms a circulation flow C1 in the auxiliary combustion chamber R1. The circulating flow C1 is induced by the airflow G and swirls in the auxiliary combustion chamber R1.

  As shown in FIG. 2, the groove 12 extends to one side with respect to the fuel injection nozzle 10. In the present embodiment, the groove portion 12 extends to the downstream side in the flow direction of the airflow G with respect to the fuel injection nozzle 10. Here, when the burner is operating, the flow direction of the airflow G is frequently switched (for example, at intervals of 30 seconds). In the meantime, the airflow G is continuously formed in one direction for a certain period of time. Therefore, the flow direction of the airflow G here means the flow direction of the airflow G at the cold start (shown by a solid line in FIG. 1).

  The regenerative burner 1 has a moving device 13 as shown in FIG. As shown in FIG. 3, the moving device 13 projects between the first injection position A that protrudes into the combustion chamber R and injects fuel, and the second injection position B that enters the auxiliary combustion chamber R1 and injects fuel. The fuel injection nozzle 10 is moved. For the moving device 13, a mechanism for moving the fuel injection nozzle 10 linearly, for example, a rack and pinion mechanism, a screw guide mechanism, a cylinder mechanism, or the like is preferably employed. When the fuel injection nozzle 10 is located at the first injection position A, the fuel injection port 10 a is disposed in the combustion chamber R. Further, when the fuel injection nozzle 10 is positioned at the second injection position B, the fuel injection port 10a is disposed in the auxiliary combustion chamber R1.

  The regenerative burner 1 includes a control device 9 as shown in FIG. The control device 9 includes a computer system that comprehensively controls the operation of each component device included in the regenerative burner 1, and controls the overall operation of the regenerative burner 1. In particular, the control device 9 of the present embodiment is configured to control the driving of the moving device 13 according to the temperature of the combustion chamber R. The temperature of the combustion chamber R is detected via, for example, a temperature detection device 14 that detects the temperature of the shell 2. The temperature detection device 14 is electrically connected to the control device 9 and outputs a detection result to the control device 9. As the temperature detection device 14, a contact type, non-contact type sensor, thermocouple, thermistor, or the like can be adopted.

  The control device 9 controls the driving of the moving device 13 based on the detection result of the temperature detecting device 14. The control device 9 of the present embodiment sets the fuel injection nozzle 10 to the first injection position A and the second injection position B with a temperature at which the combustion chamber R is sufficiently heated and capable of stable combustion (for example, 1000 ° C.) as a threshold. It is the structure which moves between. Specifically, the control device 9 positions the fuel injection nozzle 10 at the second injection position B until the temperature of the combustion chamber R reaches the threshold, and after the temperature of the combustion chamber R exceeds the threshold, The fuel injection nozzle 10 is positioned at the first injection position A.

Then, the specific operation | movement and effect | action of the thermal storage type burner 1 of the said structure are demonstrated with reference to FIG.
FIG. 4 is a diagram showing a state of combustion according to the position of the fuel injection nozzle 10 in the embodiment of the present invention. FIG. 4A is a view showing a state of combustion when the fuel injection nozzle 10 is located at the second injection position B. FIG. FIG. 4B is a view showing a state of combustion when the fuel injection nozzle 10 is located at the first injection position A. FIG. In FIG. 4, the symbol F indicates a flame.

  When performing a cold start in the regenerative burner 1, the control device 9 first drives the gas supply / exhaust device 8. As shown in FIG. 1, the gas supply / exhaust device 8 supplies the gas to the combustion chamber R from one flow path 6A and switches the switching valve 8a so that the gas in the combustion chamber R is taken in by the other flow path 6B. . The gas supplied from one flow path 6A swirls along the inner wall of the shell 2 and becomes a large airflow G reaching the other flow path 6B. A part of the swirling airflow G is introduced into the other flow path 6B, but the remaining part of the airflow G flows along the wall surface 3 of the combustion chamber R of the partition plate 4 and is rotated to the vicinity of the fuel injection nozzle 10. The

  The airflow G contains an oxidizing agent, and the fuel injection nozzle 10 injects fuel to form an air-fuel mixture. Then, the combustion chamber R is heated by burning the air-fuel mixture with an ignition device (not shown). However, during a cold start until the temperature of the combustion chamber R rises, the airflow G flowing along the wall surface 3 of the combustion chamber R has a low temperature and a high flow velocity, so misfire is likely to occur. Therefore, the control device 9 drives the moving device 13 in accordance with the temperature of the combustion chamber R, and positions the fuel injection nozzle 10 at the second injection position B as shown in FIG.

  When the fuel injection nozzle 10 is located at the second injection position B, the fuel injection nozzle 10 is immersed in the auxiliary combustion chamber R <b> 1 formed by the groove 12 and injects fuel. The groove portion 12 is formed to be recessed from the wall surface 3 to the side away from the combustion chamber R, and can form an auxiliary combustion chamber R1 that deviates from the main flow of the airflow G. Since the auxiliary combustion chamber R1 is deviated from the main flow of the airflow G, the flow becomes stagnation and the flow velocity becomes slow. Further, since the fuel injection nozzle 10 is immersed in the auxiliary combustion chamber R1, a part of the injected fuel is introduced into the auxiliary combustion chamber R1.

  The fuel introduced into the auxiliary combustion chamber R1 is burned by an ignition device (not shown). When the temperature of the auxiliary combustion chamber R1 rises due to this combustion, the heat given to the fuel injected from the fuel injection nozzle 10 immersed in the auxiliary combustion chamber R1 increases. Thus, in the auxiliary combustion chamber R1 formed by the groove portion 12, the temperature is high and the flow velocity is small, so that the flame can be stably formed. For this reason, even in the cold start, when the fuel injection nozzle 10 is located at the second injection position B, stable partial premixed combustion in a flow field having a low flow velocity in the auxiliary combustion chamber R1 is possible.

  As shown in FIG. 4A, the groove portion 12 of the present embodiment forms a circulation flow C1 in the auxiliary combustion chamber R1. For this reason, a part of the fuel injected from the fuel injection nozzle 10 can be engulfed in the circulating flow C1 and burned while remaining in the groove portion 12, and the temperature of the auxiliary combustion chamber R1 can be easily increased. . The circulating flow C1 is swirled by being drawn into the main flow of the airflow G by its viscosity. In the present embodiment, since the groove portion 12 extends downstream in the flow direction of the airflow G with respect to the fuel injection nozzle 10, a circulation flow C <b> 1 is formed on the downstream side of the fuel injection nozzle 10. By the way, the surrounding gas is also drawn by the fuel injected from the fuel injection nozzle 10 to form a circulating flow C2. Since the circulation flows C1 and C2 are swirled in the same direction, the flow can be stabilized. In addition, since the circulating flows C1 and C2 collide and cancel each other on the upstream side of the fuel injection nozzle 10 (indicated by a two-dot chain line), the groove portion 12 may be extended downstream to form the circulating flow C1. preferable.

When the temperature of the combustion chamber R exceeds the threshold temperature due to the partial premixed combustion, the control device 9 next causes the gas supply / exhaust device 8 to switch the switching valve 8a. As a result, gas is supplied from the flow path 6B to the combustion chamber R, and swirls along the inner wall of the shell 2 to form a large airflow G in the opposite direction that reaches the flow path 6A. At this time, since the gas supplied from the flow path 6B passes through the heat storage body 7 that has stored heat before switching, the gas is heated by receiving heat from the heat storage body 7. For this reason, even if the airflow G flows along the wall surface 3 of the combustion chamber R of the partition plate 4 and is rotated to the vicinity of the fuel injection nozzle 10, the temperature is sufficient and combustion is stabilized.
Here, even if the temperature of the combustion chamber R increases, if the partial premix combustion is continued, the temperature of the groove 12 exposed to the flame becomes too high, and the heat resistance performance of the wall surface 3 (partition plate 4) is increased. Adverse effects such as exceeding. Therefore, the control device 9 drives the moving device 13 according to the temperature of the combustion chamber R, and positions the fuel injection nozzle 10 at the first injection position A as shown in FIG.

When the fuel injection nozzle 10 is positioned at the first injection position A, the fuel injection nozzle 10 protrudes into the combustion chamber R and injects fuel. For this reason, the groove part 12 is not exposed to a flame, and overheating is prevented. Thus, when the fuel injection nozzle 10 is located at the first injection position A, normal diffusion combustion in the combustion chamber R is possible. When the temperature in the combustion chamber R becomes stable, the switching frequency of the switching valve 8a is increased and a normal burner operation is performed.
Therefore, by making the fuel injection position variable according to the temperature of the combustion chamber R as described above, it is possible to switch between diffusion combustion and partial premixed combustion. By forming a mixture with air, stable combustion is possible.

  Therefore, according to the above-described embodiment, the regenerative burner 1 includes the fuel injection nozzle 10 that injects fuel into the combustion chamber R in which the airflow G is formed along the wall surface 3. Groove portion 12 that forms an auxiliary combustion chamber R1 that is recessed toward the side away from the first, a first injection position A that protrudes into the combustion chamber R and injects fuel, and a second injection position that enters the auxiliary combustion chamber R1 and injects fuel. By adopting the configuration of having a moving device 13 that moves the fuel injection nozzle 10 between the fuel injection nozzle 10 and B, the flow field in which the airflow G is formed along the wall surface 3 of the combustion chamber R is also stable. A regenerative burner 1 capable of combustion is obtained.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the following description, the same or equivalent components as those of the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

FIG. 5 is a cross-sectional view showing the configuration of the fuel injection nozzle 10 in the second embodiment of the present invention. FIG. 6 is a diagram showing a state of the circulating flow in the groove portion 12 in the second embodiment of the present invention.
As shown in FIG. 5, the second embodiment differs from the above-described embodiment in that the fuel injection nozzle 10 has an auxiliary fuel injection port 10b.

As shown in FIG. 5, the auxiliary fuel injection port 10 b is provided open to the side of the fuel injection nozzle 10. The auxiliary fuel injection port 10b is configured to leak part of the fuel flowing through the fuel injection nozzle 10 to the side. For this reason, fuel is supplied from the fuel injection nozzle 10 in two directions, ie, the fuel injection port 10a and the auxiliary fuel injection port 10b.
Further, as shown in FIG. 6, the auxiliary fuel injection port 10 b is disposed so as to be inclined with respect to the side wall 12 a of the groove portion 12 at least at the second injection position B. The auxiliary fuel injection port 10b of the present embodiment is disposed obliquely with respect to a surface of the rectangular side wall 12a that does not face the fuel injection nozzle 10.

According to the above configuration, when the fuel injection nozzle 10 is located at the second injection position B as shown in FIG. 5, the fuel is directly supplied to the auxiliary combustion chamber R1 from the auxiliary fuel injection port 10b that opens to the side. Can be supplied. For this reason, fuel is sufficiently supplied to the auxiliary combustion chamber R1, and combustion in the auxiliary combustion chamber R1 can be further stabilized.
Further, according to the above configuration, as shown in FIG. 6, since the fuel is injected obliquely from the auxiliary fuel injection port 10b to the side wall 12a of the groove 12, the fuel that has collided with the side wall 12a is along the side wall 12a. Thus, a circulating flow C3 is formed on a plane whose direction is different from that of the circulating flow C1. For this reason, in the partial premixed combustion, the fuel is entrained by the two vortices of the circulation flows C1 and C3, so that the fuel can be burned while remaining in the groove 12 more reliably.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, the shape of the fuel injection nozzle 10 does not have to be a circular pipe, but may be a square pipe, for example, so that a gap through which pilot air flows between the fuel injection nozzle 10 and the through-hole 11 is not wasted. .

  In addition, for example, the present invention is not limited to a regenerative burner, but in general burners that need to inject fuel into a combustion chamber in which an airflow is formed along the wall surface, such as a gas fuel burner, a liquid fuel burner, Widely applicable to solid fuel burners and the like.

  DESCRIPTION OF SYMBOLS 1 ... Thermal storage type burner (burner), 3 ... Wall surface, 6 ... A pair of flow path, 7 ... Thermal storage body, 8 ... Gas supply exhaust apparatus (thermal storage apparatus), 9 ... Control apparatus, 10 ... Fuel injection nozzle, 10 ... Auxiliary Fuel injection port, 12 ... groove portion, 12a ... side wall, 13 ... moving device, A ... first injection position, B ... second injection position, C1 ... circulating flow, G ... airflow, R ... combustion chamber, R1 ... auxiliary combustion chamber

Claims (8)

A burner comprising a fuel injection nozzle for injecting fuel into a combustion chamber in which an airflow is formed along the wall surface,
A groove that forms an auxiliary combustion chamber that is recessed from the wall surface to the side away from the combustion chamber;
A moving device that moves the fuel injection nozzle between a first injection position that protrudes into the combustion chamber and injects the fuel and a second injection position that immerses into the auxiliary combustion chamber and injects the fuel; Yes, and
The said groove part forms the circulation flow in the said auxiliary combustion chamber with the said airflow, The burner characterized by the above-mentioned . 2. The burner according to claim 1 , wherein the groove portion extends downstream in the flow direction of the airflow with respect to the fuel injection nozzle. The burner according to claim 1 or 2 , wherein the fuel injection nozzle has an auxiliary fuel injection port that opens laterally. A burner comprising a fuel injection nozzle for injecting fuel into a combustion chamber in which an airflow is formed along the wall surface,
A groove that forms an auxiliary combustion chamber that is recessed from the wall surface to the side away from the combustion chamber;
A moving device that moves the fuel injection nozzle between a first injection position that protrudes into the combustion chamber and injects the fuel and a second injection position that immerses into the auxiliary combustion chamber and injects the fuel; Have
The fuel injection nozzle has an auxiliary fuel injection port that opens laterally. 5. The burner according to claim 3, wherein the auxiliary fuel injection port is disposed obliquely with respect to a side wall of the groove when at least the second injection position is located.   The burner according to any one of claims 1 to 5, further comprising a control device that controls driving of the moving device in accordance with a temperature of the combustion chamber.   A heat storage body and a pair of flow paths connected to the combustion chamber are provided, and when the gas is supplied from the one flow path to the combustion chamber, the gas in the combustion chamber is sucked in the other flow path. The burner according to any one of claims 1 to 6, further comprising: a heat storage device that forms the airflow. A burner comprising a fuel injection nozzle for injecting fuel into a combustion chamber in which an airflow is formed along the wall surface,
A groove that forms an auxiliary combustion chamber that is recessed from the wall surface to the side away from the combustion chamber;
A moving device that moves the fuel injection nozzle between a first injection position that protrudes into the combustion chamber and injects the fuel and a second injection position that enters the auxiliary combustion chamber and injects the fuel;
A heat storage body and a pair of flow paths connected to the combustion chamber are provided, and when the gas is supplied from the one flow path to the combustion chamber, the gas in the combustion chamber is sucked in the other flow path. And a heat storage device that forms the air flow by doing so.

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