JP5203489B2 - Combustion device - Google Patents

Description

  The present invention relates to a combustion apparatus.

  Like a regenerative burner, a combustion apparatus is used in which heat efficiency is improved by recovering heat in combustion exhaust gas and heating combustion air supplied to the combustion apparatus. In a combustion apparatus in which the temperature of combustion air is high, the NOx concentration generally tends to be high. For this reason, the method of suppressing generation | occurrence | production of NOx by delaying mixing of combustion air and fuel and burning slowly is adopted. Of course, slow combustion increases the length of the flame. However, when the width of the furnace is narrow, the flame reaches the facing furnace wall and incomplete combustion occurs, so that the combustion cannot be sufficiently delayed.

  In Patent Document 1, a combustion air is blown into a conical space in a tangential direction to form a swirling airflow, and a flame is swung on the airflow to increase the flame length, and in the furnace A combustion device is described in which the flame spreads radially.

  In Patent Document 1, a plurality of plate materials are combined to form a conical combustion space and a flow path for blowing combustion air. When the combustion air becomes extremely high like a regenerative burner, high heat resistance is required for the plate material forming the combustion space and the flow path. However, materials that can withstand such high temperatures are very expensive and are not economically reasonable for industrial furnace applications.

Japanese Patent No. 3904644

  In view of the above problems, an object of the present invention is to provide a combustion apparatus that can use high-temperature combustion air and can form a flame that swirls and expands in the radial direction.

In order to solve the above problems, a combustion apparatus according to the present invention includes a cylindrical portion that defines a cylindrical cylindrical space, a diameter-expanding portion that defines a diameter-expanding space that expands from the cylindrical space toward the inside of the furnace, From a first side surface composed of a plane in contact with the cylindrical space, a second side surface composed of a plane facing the first side surface, and a plane bent and extended from the second side surface, from the plane in contact with the cylindrical space comprising a third aspect possess, it is intended to comprise a nozzle channel communicating with the heat storage chamber containing a heat storage medium.

  According to this configuration, the third side surface that is opened to come into contact with the cylindrical space into the nozzle flow path that blows combustion air tangentially into the cylindrical space along the first side surface to form a spiral swirling airflow. By providing this, it is possible to reduce the flow path resistance when exhausting the combustion gas from the cylindrical space to the nozzle flow path, and to secure a sufficient flow rate. Further, since the third side surface is bent and extended from the second side surface, the angle formed between the side surface of the nozzle channel and the inner wall of the cylindrical portion is increased, and a sufficient thickness is provided on the entire inner wall of the combustion apparatus. It is possible to have it. For this reason, a combustion apparatus is formed with the material excellent in heat resistance, and it becomes possible to burn using high temperature combustion air, and to discharge | emit high temperature combustion gas. Further, since the combustion chamber has the enlarged diameter portion, the swirl airflow is increased in the radial direction, and the swirl airflow is further easily expanded in the radial direction in the furnace.

  In the combustion apparatus of the present invention, it is preferable that the third side surface bends and extends from the second side surface by an angle of 90 ° or less.

  According to this structure, since an acute angle is not formed in the combustion chamber, the strength can be increased.

  In the combustion apparatus of the present invention, it is preferable that an angle on the cylindrical space side formed between the third side surface and the first side surface is 90 ° or less.

  According to this configuration, when the combustion gas is discharged from the nozzle flow path, the air flow along the third side surface is incident and reflected in the direction toward the second side surface with respect to the first side surface, so that the exhaust resistance Becomes smaller.

  Moreover, the combustion apparatus of this invention WHEREIN: You may expand the said enlarged diameter part in step shape.

  According to this configuration, in the diameter expansion space, the combustion air, the air-fuel mixture or the combustion gas flowing toward the inside of the furnace is separated from the wall surface at each step of the diameter expansion portion, and a vortex that inhibits the flow is generated. For this reason, the spiral flow formed in the cylindrical space keeps turning even in the enlarged diameter space.

  In the combustion apparatus of the present invention, a continuous or intermittent spiral groove or protrusion may be provided on the inner wall of the cylindrical portion.

  According to this configuration, the spiral groove or protrusion guides the combustion air and promotes the formation of the swirling airflow.

  In the combustion apparatus of the present invention, the groove or the protrusion may be wider as it gets closer to the enlarged diameter portion.

  According to this configuration, it is possible to prevent the swirling airflow from being biased and the flame from extending only a part in the circumferential direction.

  In the combustion apparatus of the present invention, the grooves or protrusions may be provided intermittently, and the grooves or protrusions adjacent in the circumferential direction may be alternately arranged in the axial direction.

  According to this configuration, the combustion air can be exchanged upstream and downstream of the swirling airflow formed in the groove or between the protrusions, so that the flame diffusion effect is high.

1 is an axial sectional view of a combustion apparatus according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view perpendicular to the axis of the combustion apparatus of FIG. 1. It is an axial sectional view of the different direction of the combustion apparatus of FIG. It is an axial sectional view of the combustion device of a 2nd embodiment of the present invention. FIG. 5 is a cross-sectional view perpendicular to the axis of the combustion apparatus of FIG. 4. It is an axial sectional view of a combustion apparatus according to a third embodiment of the present invention. It is an axial sectional view of the combustion device of a 4th embodiment of the present invention. It is an axial sectional view of a combustion apparatus according to a fifth embodiment of the present invention. FIG. 9 is a cross-sectional view perpendicular to the axis of the combustion device of FIG. 8.

  Embodiments of the present invention will now be described with reference to the drawings. 1 to 3 show a combustion apparatus according to a first embodiment of the present invention.

  The combustion apparatus of this embodiment is configured by attaching a burner body 3 to a furnace wall 2 that defines a furnace internal space 1. The burner body 3 constitutes a cylindrical portion 5 that defines a cylindrical cylindrical space 4 therein. The furnace wall 2 is formed with a diameter-expanded portion 7 that defines a diameter-expanded space 6 that expands from the cylindrical space 4 toward the furnace space 1. The cylindrical space 4 and the expanded diameter space 6 constitute a combustion chamber having a characteristic shape of the combustion apparatus of the present embodiment. The diameter expansion space 6 of the present embodiment has a larger diameter expansion ratio toward the furnace inner space 1 side.

  The burner body 3 has a nozzle channel 8 that opens to the top of the cylindrical space 4. The nozzle flow path 8 has a first side surface 8a composed of a flat surface in contact with the cylindrical surface of the cylindrical space 4, and a second side surface composed of a flat surface facing the first side surface 8a and extending in parallel with the first side surface 8a. 8b and a third side surface 8c which is bent from the second side surface 8b and extends at an angle of 90 ° and which is a plane in contact with the cylindrical space 4. The top surface of the nozzle channel 8 extends so as to be continuous with the top surface 8d of the cylindrical space 4, and the bottom surface 8e of the nozzle channel 8 is parallel to the top surface. That is, the top surface and the bottom surface of the nozzle channel 8 are planes that are perpendicular to the central axis of the cylindrical space 4.

  The nozzle channel 8 is defined by a first side surface 8a and a second side surface 8b, and has a slit-shaped run-up portion 9 having a constant cross section and two contact points of the cylindrical space 4 intersecting each other at an angle of 90 ° or less. It consists of the opening part 10 defined by the 1st side surface 8a and the 3rd side surface 8c which are surfaces.

  The other end of the nozzle channel 8 communicates with the heat storage chamber 11 that houses the heat storage body. Specifically, the other end of the nozzle flow path 8 is connected to a transition flow path 13 that transitions from a rectangular shape whose cross-sectional shape matches the nozzle flow path 8 to a circular shape that matches the connection flow path 12 communicating with the heat storage chamber 11. Has been.

  Further, in the opening 10 of the nozzle flow path 8, a gas nozzle 14 for supplying fuel gas is opened at a position near the top surface 8d of the first side surface 8a. The gas nozzle 14 is also supplied with primary combustion air and incorporates an ignition device.

  In the present embodiment, the combustion air supplied after being heated in the heat storage chamber 11 is blown in a tangential direction along the inner wall of the cylindrical portion 5 from the nozzle flow path 8 and swirls spirally into the cylindrical space 4. Create an air flow. The flame formed by the combustion of the fuel supplied from the gas nozzle 14 rides on this swirling airflow and extends spirally.

  When the flame (swirl airflow) reaches the enlarged diameter portion 7, the swirl radius of the swirl airflow increases in accordance with the shape. And the swirling airflow which reached | attained the furnace space 1 forms the spiral flow which spreads to a perimeter along the inner surface of the furnace wall 2 on the radial direction outer side. As a result, the apparent flame spreads in an umbrella shape, and the length of the apparent combustion flame is shortened even if the combustion of the fuel is delayed and slow combustion is performed. For this reason, the combustion apparatus of this embodiment is applicable also to a narrow furnace where the opposing furnace walls are at a short distance.

  Further, when the vortex is formed by the combustion gas in this way, the central portion of the vortex becomes a negative pressure. For this reason, the combustion gas desorbed from the spiral flow is sucked into the center of the vortex and is caught in the flame. As a result, the unburned fuel gas in the combustion gas can be completely burned, so that the combustion temperature can be lowered to reduce NOx.

  In the present invention, the nozzle flow path 8 includes a run-up portion 9 for rectifying combustion air supplied to the cylindrical space 4. For this reason, the combustion air can be blown into the nozzle flow path 8 so as to flow along the inner wall of the cylindrical portion 5.

  Further, the nozzle flow path 8 includes an opening 10 that is wide open toward the cylindrical space 4. For this reason, when exhausting the combustion gas in the furnace space 1 through the cylindrical space 4 for heat recovery in the heat storage chamber 11, the combustion gas flows into the nozzle flow path 8 from a wide range above the cylindrical space 4. Can do. That is, the opening 10 reduces the flow resistance when exhausting the combustion gas in the furnace space 1 and increases the exhaust efficiency.

  As described above, in order to increase the exhaust efficiency, the airflow along the third side surface 8c is incident and reflected from the cylindrical space 4 side toward the transition flow path 13 side with respect to the first side surface 8a. It is preferable that the angle be set to a certain angle. That is, it is preferable not to form an angle larger than 90 ° on the side of the cylindrical space 4 with respect to the first side surface 8a like the third side surface 8c 'shown by a two-dot chain line in FIG.

  Further, in the combustion apparatus of the present invention, since the third side surface 8c extends from the second side surface 8b at an angle of 90 °, the second side surface 8b shown by the two-dot chain line in FIG. Since there is no thin structure projecting into the internal space like the corner formed between the side surface 8c ', the entire inner surface is inferior in mechanical strength like a castable refractory, but has high heat resistance. Can be covered with material. For this reason, the combustion apparatus of the present invention can be designed not to be damaged by the combustion air heated to a high temperature in the heat storage chamber 11.

  4 to 5 show a combustion apparatus according to a second embodiment of the present invention. In the following description of the embodiment, the same constituent elements as those of the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the present embodiment, a spiral groove 15 is formed on the inner wall of the cylindrical portion 5 that forms the cylindrical space 4. Moreover, the diameter expansion space 6 of this embodiment is expanded in steps. In other words, the inner wall surface of the enlarged diameter portion 7 is composed of a plurality of cylinders whose diameters are increased stepwise.

  The spiral groove 15 guides the combustion air blown from the nozzle flow path 8 so as to swirl along the groove 15. This ensures the formation of the swirling airflow. Further, if the pitch of the grooves 15 is reduced, the number of revolutions of the combustion air in the cylindrical space 4 can be increased. Thereby, the substantial length of the flame in the cylindrical space 4 can be lengthened, combustion can be further delayed, and further NOx reduction can be achieved.

  The step-like enlarged diameter portion 7 is a flat wall surface along the flow with respect to the airflow swirling in the circumferential direction, but is an uneven wall surface with respect to the airflow toward the furnace space 1. Therefore, every time the airflow toward the furnace space 1 gets over each step, the airflow separates from the wall surface and generates a vortex that hinders the flow. As a result, the swirling airflow formed in the cylindrical space 4 is prevented from changing the direction in the axial direction in the enlarged diameter portion 7, and the swirling of the combustion air and the combustion gas is maintained. Thereby, it is set as the shape which opened the umbrella-shaped flame formed in the furnace space 1 largely.

  In the present embodiment, the second side surface 8b of the nozzle channel 8 extends in a direction slightly inclined with respect to the first side surface 8a. That is, the first side surface 8a and the second side surface 8b face each other to form a slit-shaped flow path, but the width of the flow path to be formed is not necessarily constant. For example, the second side surface 8 b may extend in a direction in which the width of the flow path becomes narrower toward the cylindrical space 4.

  Further, as in the present embodiment, the third side surface 8c of the nozzle flow path 8 may be bent and extended from the second side surface 8b by an angle smaller than 90 °. Thereby, the flow resistance when exhausting the combustion gas in the furnace space 1 can be further reduced, the exhaust efficiency can be increased, and the angle formed by the second side surface 8b and the third side surface 8c. Makes it easy to obtain high strength.

  FIG. 6 shows a combustion apparatus according to a third embodiment of the present invention. In the present embodiment, a spiral groove 15 is formed on the inner wall of the cylindrical portion 5 such that the axial width increases at a certain rate as the diameter-expanding space 6 is approached.

  Thus, the flow velocity of the swirling air flow becomes uniform in the circumferential direction by increasing the width of the groove 15. In particular, it is preferable that the grooves 15 approach each other at the lower portion of the cylindrical portion 5 and the grooves 15 exist over substantially the entire circumference at the lower end of the cylindrical space 4. By doing so, it is possible to prevent the swirling airflow from being biased and the flame from extending long in only one direction, and the flame can be injected substantially evenly from the entire circumference.

  In addition, the enlarged diameter portion 7 of the present embodiment has a stepped inner wall surface with rounded corners. Even in such a shape, the function of maintaining the swirl of the airflow can be achieved.

  FIG. 7 shows a combustion apparatus according to a fourth embodiment of the present invention. In the present embodiment, a spiral protrusion 16 is formed on the inner wall of the cylindrical portion 5.

  This projection 16 also guides the combustion air blown from the nozzle flow path 8 so as to swirl spirally, similarly to the groove 15 of the second embodiment.

  Further, as shown in the present embodiment, the enlarged diameter portion 7 may form a conical enlarged diameter space 6.

  8 and 9 show a combustion apparatus according to a fifth embodiment of the present invention. In the present embodiment, a spiral protrusion 16 provided intermittently about every half circumference is formed on the inner wall of the cylindrical portion 5. Furthermore, in this embodiment, the protrusions 16 adjacent to each other in the circumferential direction are arranged so as to be shifted in the axial direction by a half pitch so as to be alternated in the axial direction of the cylindrical space 4.

  In this embodiment, a mass of combustion air (and fuel and combustion gas) guided between two axially adjacent projections 16 is divided into two by the next projection 16 on the downstream side in the circumferential direction. The Thus, the flame diffusion effect can be enhanced by partially replacing the upstream combustion air and the downstream combustion air adjacent to each other in the swirling airflow.

DESCRIPTION OF SYMBOLS 1 ... Furnace space 2 ... Furnace wall 3 ... Burner main body 4 ... Cylindrical space 5 ... Cylindrical part 6 ... Expanded space 7 ... Expanded part 8 ... Nozzle flow path 8a ... 1st side surface 8b ... 2nd side surface 8c ... 3rd side surface 9 ... Running part 10 ... Opening part 11 ... Heat storage room 12 ... Connection flow path 13 ... Transition flow path 14 ... Gas nozzle 15 ... Groove 16 ... Protrusion

Claims (7)

A cylindrical portion that defines a cylindrical cylindrical space;
A diameter-expanding portion that defines a diameter-expanding space that expands from the cylindrical space into the furnace;
From a first side surface composed of a plane in contact with the cylindrical space, a second side surface composed of a plane facing the first side surface, and a plane bent and extended from the second side surface, from the plane in contact with the cylindrical space comprising a third aspect possess, combustion apparatus, characterized in that it comprises a nozzle passage which communicates with the heat storage chamber containing a heat storage medium.   The combustion apparatus according to claim 1, wherein the third side surface is bent and extended by an angle of 90 ° or less from the second side surface.   3. The combustion apparatus according to claim 1, wherein an angle on the cylindrical space side formed between the third side surface and the first side surface is 90 ° or less. 4.   The combustion apparatus according to any one of claims 1 to 3, wherein the diameter-expanded portion expands in a stepped manner.   The combustion apparatus according to any one of claims 1 to 4, wherein a continuous or intermittent spiral groove or protrusion is provided on an inner wall of the cylindrical portion.   The combustion apparatus according to claim 5, wherein the groove or the projection becomes wider as it gets closer to the enlarged diameter portion.   The combustion apparatus according to claim 5 or 6, wherein the grooves or protrusions are provided intermittently, and the grooves or protrusions adjacent in the circumferential direction are alternately arranged in the axial direction.

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