JP2008175427A - Combustion apparatus and boiler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a burner capable of reducing noxious substance using at least either liquid fuel or gas fuel. <P>SOLUTION: This combustion apparatus comprises a fuel jet part 42 for jetting at least either liquid fuel or gas fuel, and air exhaust parts 47 for exhausting combustion air, wherein a preheating part is provided upstream of the air exhaust parts 47. The preheating part is constituted using one or more preheating burners 60 jetting the fuel, and each of the preheating burners 60 is disposed on a circumference centering on the fuel jet part 42 corresponding to the air exhaust part 47. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a combustion apparatus and a boiler. More specifically, the present invention relates to a combustion apparatus and a boiler capable of reducing harmful substances using at least one of liquid fuel and gaseous fuel.

  Conventionally, a boiler having a can having a group of water tubes arranged in an annular shape is well known, and in such a boiler, a burner is generally arranged at the center of the water tube group. . That is, in the boiler having such a configuration, the central portion of the annularly arranged water tube group functions as a combustion chamber for burning the fuel supplied from the burner.

  Moreover, in the burner which comprises a boiler, many proposals are made regarding the combustibility improvement technique and the reduction technique of harmful substances (NOx, CO, soot, etc.) (refer patent document 1).

  For example, the burner disclosed in Patent Document 1 is a burner for the purpose of preventing poor combustion due to the bias of the flame, but even if this technique is used, it has a great effect on reducing harmful substances. Can't hope. That is, although various proposals have been made conventionally, there is no known technique that achieves a high level of both combustibility improvement and reduction of harmful substances (NOx, CO, soot, etc.). In particular, the burner that uses liquid fuel is more prominent than the burner that uses gaseous fuel.

JP 2005-106310 A

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and is a combustion capable of improving combustibility and reducing harmful substances using at least one of liquid fuel and gaseous fuel. It is an object to provide an apparatus. Moreover, this invention makes it a subject to provide the boiler which can implement | achieve combustibility improvement and reduction of a harmful substance.

  The present invention has been made in order to solve the above-described problems, and includes a fuel injection unit that ejects at least one of liquid fuel and gaseous fuel, and a combustion device that includes an air ejection unit that ejects combustion air. And it has the preheating part in the upstream of the said air ejection part, It is characterized by the above-mentioned.

  According to such a configuration, since the preheating part is provided on the upstream side of the air ejection part, the high-temperature combustion air can be supplied in the vicinity of the fuel ejection part. Therefore, according to such a configuration, even if the fuel ejected from the fuel ejection section is a liquid fuel, vaporization combustion (fuel vaporization) is promoted, and low dust, low CO, and low NOx are achieved. Can be planned. That is, it is possible to reduce harmful substances.

  Further, in the combustion apparatus according to the present invention, a plurality of the air ejection portions for ejecting combustion air are provided around the fuel ejection portion, and each of the air ejection portions is upstream of the air ejection portion. A configuration in which the preheating portion is provided corresponding to the ejection portion is preferable.

  According to this preferable configuration, since the preheating unit is provided on the upstream side of the plurality of air ejection units corresponding to the air ejection units, the high-temperature combustion air is well balanced. It can supply to the fuel ejection part vicinity. Therefore, according to such a structure, the combustion apparatus which can maintain the stable combustion state can be obtained.

  Moreover, in the combustion apparatus concerning this invention, it is preferable that the said preheating part is comprised using one or more preheating burners which eject the said fuel.

  According to this preferable configuration, since the preheating portion is configured by using one or more preheating burners, the combustion air jetted in the vicinity of the fuel jetting portion is effectively heated and the combustion is performed. The oxygen concentration in the working air can be reduced. Therefore, according to this preferable configuration, in addition to the above-described effects, it is possible to achieve low NOx by supplying the combustion air having a low oxygen concentration in the vicinity of the fuel ejection portion.

  Further, in the combustion apparatus according to the present invention, it is preferable that each of the preheating burners is disposed on a circumference centering on the fuel ejection portion corresponding to the air ejection portion.

  According to this preferable configuration, one preheating is provided at each of the upper positions of the air ejection portions provided around the fuel ejection portions (provided on a circumference centering on the fuel ejection portions). Since the burner is provided, high-temperature combustion air can be supplied in a more balanced manner.

  Further, in the combustion apparatus according to the present invention, a plurality of the air ejection portions that eject combustion air are provided around the fuel ejection portion, and each of the air ejection portions has an air ejection direction. It is preferable to have a configuration having a guide part to be controlled and a diffusion part for diffusing the ejected air.

  According to this preferable structure, since the air ejection part has the guide part, the flow of the flame (gas) is controlled according to the structure of the can body (position of the gas flow path, etc.), and the harmful substances are reduced ( Reduction of dust and NOx) can be achieved. Further, since the air ejection part has the diffusion part, the fuel and the combustion air can be effectively mixed to reduce dust. According to such a configuration (a configuration having a diffusion portion), the mixing state of the fuel and air ejected from the fuel ejection portion can be made partially non-uniform. In other words, the mixing state is not simply improved, but a partly intentionally non-uniform mixing state is formed by the diffusing section. Therefore, when this combustion device is applied to a boiler, the gas temperature in the can is lowered. Thus, the NOx value can be reduced. Further, according to such a configuration, since the plurality of air ejection portions are provided around the fuel ejection portion, it is possible to form a divided flame and reduce NOx. In addition, according to such a configuration, by having the guide portion, the combustion air can be focused and brought into contact with the fuel at a high speed. Therefore, when liquid fuel is used as the fuel, The combustion state of the flame approaches that of vaporization combustion, and it is possible to reduce NOx. Further, by increasing the flow rate of the air jetted by providing the guide portion, the gas around the guide portion is entrained (because it is in a state of self-recirculation), so it is possible to reduce NOx. it can.

  The present invention has been made in order to solve the above-described problem, and a can body having an inner water tube group and an outer water tube group arranged in an annular shape, and at least liquid fuel and gaseous fuel in the can body. It is a boiler provided with the combustion apparatus which can burn one fuel, Comprising: The said combustion apparatus is a combustion apparatus which has the structure mentioned above.

  According to the boiler according to such a configuration, since the combustion apparatus that can exhibit the various effects described above is mounted, it is possible to obtain a boiler capable of reducing harmful substances and the like. Furthermore, according to the boiler according to such a configuration, low dust combustion is possible, so that the can can be downsized.

  ADVANTAGE OF THE INVENTION According to this invention, the combustion apparatus which can implement | achieve combustibility improvement and reduction of a hazardous | toxic substance can be obtained using at least one fuel of liquid fuel and gaseous fuel. Moreover, according to this invention, the boiler which can implement | achieve combustibility improvement and reduction of a harmful substance can be obtained.

  Before describing the embodiments of the present invention, terms used in this specification will be described.

  In the present specification, when simply referred to as “gas”, the gas is a concept including at least one of a gas during a combustion reaction and a gas for which the combustion reaction has been completed, and may also be referred to as a combustion gas. In other words, the gas includes both the gas in the combustion reaction and the gas in which the combustion reaction is completed, the gas in the combustion reaction only, or the gas in which the combustion reaction is completed only. It is a concept that includes. Hereinafter, the same concept is used unless otherwise described.

  Further, the exhaust gas means a gas in which the combustion reaction is completed or almost completed. Further, unless otherwise specified, exhaust gas means either or both of the gas that passes through the boiler body and reaches the chimney and the gas that circulates in the body.

  Further, the gas temperature means the temperature of the gas during the combustion reaction unless otherwise specified, and is synonymous with the combustion temperature or the combustion flame temperature. Further, the suppression of the gas temperature means that the maximum value of the gas (combustion flame) temperature is kept low. In general, the combustion reaction is extremely small in the above-mentioned “gas for which the combustion reaction has been completed”, but continues, so “completion of the combustion reaction” means 100% completion of the combustion reaction. It is not a thing.

  Hereinafter, embodiments of the present invention will be described.

  First, a combustion apparatus according to a first aspect of the present embodiment is a combustion apparatus that includes a fuel ejection portion that ejects at least one of liquid fuel and gaseous fuel, and an air ejection portion that ejects combustion air. And it has the preheating part in the upstream of the said air ejection part, It is characterized by the above-mentioned.

  Further, in the combustion apparatus according to the second aspect of the present embodiment, in the configuration of the first aspect, a plurality of the air ejection parts for ejecting combustion air are provided around the fuel ejection part, The preheating portion is provided on the upstream side of the air ejection portion so as to correspond to each air ejection portion.

  Further, in the combustion apparatus according to the third aspect of the present embodiment, in the configuration of the first aspect or the second aspect, the preheating unit is configured by using one or more preheating burners that eject the fuel.

  Further, in the combustion apparatus according to the fourth aspect of the present embodiment, in the configuration of the third aspect, each of the preheating burners corresponds to the air ejection part on a circumference around the fuel ejection part. It is arranged.

  Further, in the combustion apparatus according to the fifth aspect of the present embodiment, in the configuration of any one of the first aspect to the fourth aspect, a plurality of the air ejection portions that eject combustion air are disposed around the fuel ejection portion. Each of the air ejection portions is provided to have a guide portion for controlling the air ejection direction and a diffusion portion for diffusing the ejected air.

  The boiler according to the sixth aspect of the present embodiment includes a can having an inner water tube group and an outer water tube group arranged in an annular shape, and burning at least one of liquid fuel and gaseous fuel in the can And a combustion apparatus according to any one of the first to fifth aspects described above.

<First Example>
Hereinafter, the boiler concerning the 1st example of the present invention is explained based on a drawing.

  FIG. 1 shows an explanatory view of a longitudinal section of a boiler according to a first embodiment of the present invention. FIG. 2 shows a simplified explanatory view of a cross section taken along line II-II in FIG. FIG. 3 shows a simplified explanatory view of a cross section taken along line III-III in FIG. FIG. 4 shows a simplified explanatory view of a cross section taken along line IV-IV in FIG.

  As shown in FIG. 1 etc., the boiler 1 concerning a present Example is comprised using the can 10 which has the water pipe group arrange | positioned circularly, and the burner 40 arrange | positioned in the center part of these water pipe groups. A wind box 100 for supplying combustion air to the burner 40 is provided above the burner 40. In the boiler 1 according to the present embodiment, a plurality of preheating burners 60 (corresponding to the “preheating portion” of the present invention) are provided in the wind box 100. The burner 40 and the preheating burner 60 correspond to the “combustion device” according to the present invention.

  The can body 10 is configured by standing a plurality of water pipe groups (an inner water pipe group 20 and an outer water pipe group 30) between the upper header 11 and the lower header 12. The respective water tube groups 20 and 30 are arranged in a substantially concentric ring shape, and an outer water tube group 30 is provided at a predetermined interval from the inner water tube group 20, and the inner water tube group 20, the outer water tube group 30, and the like. An annular gas flow path 80 is formed between the two.

  In the present embodiment, the inner water tube group 20 is configured using a plurality of inner water tubes 21 and first vertical fin portions 24. Each inner water pipe 21 is formed in an annular shape with a substantially uniform predetermined interval, and a first vertical fin connected between each inner water pipe 21 so as to eliminate a gap between adjacent inner water pipes 21. A portion 24 is provided. That is, in the present embodiment, the inner water tube group 20 is configured in an annular shape in close contact with the first vertical fin portion 24.

  Moreover, the lower end part 21a of each inner side water pipe 21 is a reduced diameter part, and in the inner side water pipe group 20 concerning a present Example, the space around this reduced diameter lower end part 21a is the inner side formed circularly. It will function as the gas flow path 25. That is, the inner gas channel 25 functions to guide the gas generated inside the inner water tube group 20 to the annular gas channel 80.

  In the present embodiment, the outer water tube group 30 is configured using a plurality of outer water tubes 31 and a second vertical fin portion 34. Each outer water pipe 31 is formed in an annular shape with a substantially uniform predetermined interval, and a second vertical fin connected to each other to eliminate a gap between adjacent outer water pipes 31. A portion 34 is provided. That is, in the present embodiment, the outer water pipe group 30 is configured in an annular shape in a close state using the second vertical fin portion 34.

  Moreover, the upper end part 31a of each outer side water pipe 31 is a diameter-reduced part, and in the outer side water pipe group 30 concerning a present Example, the space around this diameter-reduced upper end part 31a is the outer side formed circularly. It functions as the gas flow path 35. The outer gas channel 35 functions to guide the gas introduced into the annular gas channel 80 toward the exhaust cylinder 90. That is, the gas generated inside the inner water tube group 20 is collected in the exhaust pipe 90 via the inner gas flow path 25, the annular gas flow path 80, and the outer gas flow path 35, and the can is It is discharged outside the body 10.

  Each inner water tube 21 constituting the inner water tube group 20 is provided with a plurality of first stud fins 22 (stud fins) at the lower end 21a. The inner water pipe 21 located on the downstream side (downstream side of the gas flow) where the first stud fins 22 are provided has a plurality of flat plate-like first fins 23 (flat plate shape) on the annular gas flow path 80 side. Fins).

  Each outer water pipe 31 constituting the outer water pipe group 30 is provided with a plurality of second stud fins 32 (stud fins) in the vicinity of the inner gas flow path 25. The outer water pipe 31 located on the downstream side (downstream side of the gas flow) where the second stud fins 32 are provided has a plurality of flat plate-like second fins 33 (flat plate shape) on the annular gas flow path 80 side. Fins).

  That is, in the present embodiment, the stud fins (first stud fins 22) are connected to the inner water pipe group 20 (the inner water pipe 21 constituting the inner water pipe group 20) and the outer water pipe group 30 (the outer water pipe 31 constituting the outer water pipe group 30) in the vicinity of the inner gas flow path 25. , Second stud fins 32) are provided, and flat fins (first fins 23, second fins 33) are provided downstream of these stud fins (downstream in the gas flow). In the present embodiment, the first fin 23 and the second fin 33 are provided to have an inclination angle of 80 ° (an inclination angle of 10 ° with respect to the horizontal) with respect to the gas flow (vertical flow). ing.

  5, 6 and 7 are schematic views of a wind box and a combustion apparatus provided in the boiler according to the present embodiment. Here, FIG. 5 shows an explanatory view of a longitudinal section of the wind box and the combustion apparatus according to the present embodiment, FIG. 6 shows a bottom view of the wind box and the combustion apparatus shown in FIG. 5, and FIG. The schematic of the VII-VII arrow line direction of FIG. 5 is shown. In FIG. 7, illustrations of the igniters provided in the burner 40 and each preheating burner 60 are omitted in order to prevent the drawing from becoming complicated.

  The burner 40 constituting the boiler 1 according to the present embodiment is installed in a wind box 100 as air supply means for supplying combustion air to the burner 40 (see FIGS. 1 and 5). A plurality of (six in this embodiment, six as described later) preheating burners 60 (first preheating burner 60A to sixth preheating burner 60F) are provided on the upstream side of the burner 40 in the wind box 100. ing. The burner 40 and the preheating burner 60 correspond to the “combustion device” of the present invention. In this embodiment, air supplied from a blower (not shown) is sent into the wind box 100 through the blower duct 101. In the present embodiment, the configuration of the blower is omitted because it is a well-known technique.

  As shown in FIGS. 5 and 6 and the like, the burner 40 according to the present embodiment has a nozzle portion 42 (first nozzle portion 42a, second nozzle portion 42b) for spraying liquid fuel (the “fuel ejection portion” of the present invention). And the air supplied to the wind box 100 via the blower and the air duct 101 is sprayed from the nozzle part 42 through the igniter 41 provided so that the tip thereof is positioned in the vicinity of the first nozzle part 42a. Air supply path (first air supply path 43 for primary air supply, second air supply path 45 for secondary air supply) provided for mixing with liquid fuel to be mixed and supplied from the first air supply path 43 A central air ejection section 46 that ejects the generated air to the combustion chamber 16 side, and a plurality of ambient air ejection sections 47 that eject the air supplied from the second air supply path 45 to the combustion chamber 16 side (“air” of the present invention Spout Considerable) (which is configured with a first ambient air injection unit 47a~ sixth ambient air ejection section 47f).

  As the nozzle part 42 according to the present embodiment, a first nozzle part 42a that sprays liquid fuel at the time of low combustion and high combustion, and a second nozzle part 42b that sprays liquid fuel only at the time of high combustion are provided. . That is, the nozzle part 42 includes a first nozzle part 42a that is in a fuel supply state during low combustion (and a high combustion period) and a second nozzle part 42b that is in a fuel supply state together with the first nozzle part 42a during high combustion. The fuel supply state in each nozzle part 42 is appropriately switched according to the combustion load of the boiler. That is, each nozzle part 42a, 42b is on-off controlled as needed.

  The first air supply path 43 constituting the burner 40 is configured using a first cylinder member 53 provided outside the nozzle portion 42, and the second air supply path 45 uses a second cylinder member 55. Configured. That is, the inner area of the first cylinder member 53 functions as the first air supply path 43, and the area formed between the first cylinder member 53 and the second cylinder member 55 functions as the second air supply path 45. . An air preheating cylinder member 54 is provided above the second cylinder member 55 so as to surround the preheating burner 60 provided on the upstream side of the burner 40. The air preheating cylinder member 54 forms an air preheating region 44 above the burner 40, and the combustion air supplied to the burner 40 is heated by the flame generated by the preheating burner 60.

  A first air supply plate 56 in which a central air ejection portion 46 is perforated is provided at the front end portion of the first cylinder member 53 (the end portion on the combustion chamber 16 side of the boiler 1), and is supplied from the wind box 100. The air heated by the preheating burner 60 is ejected to the combustion chamber 16 side through the central air ejection part 46. Further, a second air supply plate 57 provided with a plurality of ambient air ejection portions 47 is provided at the tip end portion (the end portion on the combustion chamber 16 side of the boiler 1) of the second cylinder member 55, and the wind box 100 is provided. The air heated by the preheating burner 60 is ejected not only to the central air ejection part 46 but also to the combustion chamber 16 side through the plurality of ambient air ejection parts 47.

  The ambient air ejection part 47 (corresponding to the “air ejection part” of the present invention) is provided around the nozzle part 42 as shown in FIGS. 5 and 6. The ambient air ejection portion 47 is configured to eject air inward so that the gas generated by the burner 40 does not spread outward. According to such a configuration, the liquid fuel and the flame (gas) at the combustion start stage are less likely to come into contact with the inner water tube group 20 of the can 10, so that inappropriate imperfect combustion near the burner 40 is eliminated, and CO and The generation of dust can be effectively prevented.

  The ambient air ejection part 47 according to the present embodiment is directed to the inside (nozzle part 42 side) of the air ejected from each ambient air ejection part 47 (first ambient air ejection part 47a to sixth ambient air ejection part 47f). Of the air ejected from the guide portions 58 (first guide portion 58a to sixth guide portion 58f) and the surrounding air ejection portions 47 (first ambient air ejection portion 47a to sixth ambient air ejection portion 47f). It has a diffusion part 59 (first diffusion part 59a to sixth diffusion part 59f) that promotes diffusion.

  More specifically, in the present embodiment, six substantially trapezoidal through-hole portions 51 (first through-hole portion 51a to sixth through-hole portion 51f) are perforated in the second air supply plate 57, A guide part 58 (first guide part 58a to sixth guide part 58f) is configured by using a plate-like member on the outer peripheral side (the side far from the nozzle part 42) of each through-hole part 51. The guide portion 58 is configured to cover a part of each through-hole portion 51. In this embodiment, a portion not covered by the guide portion 58 is ejected from the ambient air ejection portion 47. Functions as a diffusion part 59 (first diffusion part 59a to sixth diffusion part 59f) that promotes diffusion of air.

  Each guide part 58 has at least a part of air ejected from each ambient air ejection part 47 (mainly air in a region covered by the guide part 58 of the through-hole part 51) inside (nozzle part 42 side). The plate-like member is inclined to be ejected in the direction. The inclination angle θ (attachment angle) at this time is preferably about 20 ° to 60 °.

  In addition, the height of each guide portion 58 is set so that the liquid fuel sprayed from the nozzle portion 42 in a cone shape (triangular pyramid shape with the nozzle portion 42 as a vertex) does not contact each guide portion 58. Yes.

  As described above, the diffusing portion 59 (the first diffusing portion 59a to the sixth diffusing portion 59f) is a portion of the through-hole portion 51 that is not covered by the guide portion 58 (indicated by a broken line in FIGS. 5 and 6). Area). Since this part (diffusion part 59) is not provided with an element for rectifying the air supplied via the second air supply path 45 such as the guide part 58 or the like, the part is diffused from the diffusion part 59. The air will expand rapidly.

  Therefore, in the burner 40 according to the present embodiment, the air ejected from the ambient air ejecting portion 47 is guided inward by the guide portion 58 and a part thereof is promoted to diffuse by the diffusing portion 59. .

  FIG. 8 is an explanatory view of a longitudinal section of a preheating burner constituting the combustion apparatus according to the present embodiment.

  As shown in FIG. 8, the preheating burner 60 according to the present embodiment includes a preheating nozzle portion 62 for spraying liquid fuel, a preheating igniter 61 provided so that its tip is positioned in the vicinity of the preheating nozzle portion 62, The preheating burner cylinder member 63 provided so as to cover the preheating nozzle part 62 and the preheating flame holding part 64 provided near the tip of the preheating nozzle part 62 are configured.

  The preheating burner cylinder member 63 according to the present embodiment prevents the combustion air supplied from the blower from directly blowing on the preheating nozzle part 62 to cause the flame to blow out, and burns in the vicinity of the preheating nozzle part 62. It functions to supply air. The preheating burner cylinder member 63 is provided with a large number of air supply holes 65, and combustion supplied from the blower (not shown) and the air duct 101 into the wind box 100 through the air supply holes 65. The working air is sent to the vicinity of the preheating nozzle portion 62.

  In addition, the preheating flame holding section 64 according to the present embodiment functions to promote the turbulent air flow at the tip of the preheating nozzle section 62 and improve the flame holding performance. The preheating flame holding section 64 is configured by using a disk-like member that can be inserted into the preheating burner cylinder member 63, and a preheating nozzle section 62 in the preheating burner cylinder member 63 by a support member (not shown). It is installed near the tip. In the central portion of the preheating flame holding portion 64, a fuel ejection hole portion (not shown) is bored so that the liquid fuel ejected from the preheating nozzle portion 62 can pass therethrough. Further, the preheating flame holding portion 64 is provided with a plurality of through-hole portions (for example, a circular hole portion, an elliptic hole portion, a radial hole portion, a concentric hole portion, etc.) in order to promote air turbulence. ing.

  Further, in the present embodiment, the preheating burner 60 configured as shown in FIG. 8 is provided on the upstream side of the ambient air ejection part 47 and on each ambient air ejection part 47 as shown in FIGS. Correspondingly provided. Specifically, each preheating burner 60 (first preheating burner 60A to sixth preheating burner 60F) corresponds to the ambient air ejection part 47 (first ambient air ejection part 47a to sixth ambient air ejection part 47f). The nozzle portion 42 is arranged on the circumference. That is, it is configured to effectively heat the combustion air ejected from the ambient air ejection section 47.

  The boiler 1 concerning a present Example is comprised as mentioned above, and acts as follows based on the structure. Hereinafter, the operation will be specifically described with reference to FIGS.

  In this embodiment, regardless of whether the burner 40 is operated in the low combustion state or the high combustion state, the six preheating burners 60 (first preheating burner 60A to sixth preheating burner 60F) are operated, The combustion air supplied to the burner 40 is preheated. Specifically, an air blower (not shown) is driven, and air supplied into the wind box 100 through the air duct 101 is introduced into the preheating burner cylinder member 63 of each preheating burner 60 from the air supply hole 65. The Next, the preheating igniter 61 is energized in accordance with the timing at which the liquid fuel is sprayed from the preheating nozzle 62, and the liquid fuel mixed with air is ignited. The flame formed by this ignition is held in the vicinity of the preheating flame holding portion 64.

  In the present embodiment, the six preheating burners 60 provided on the upper position (upstream side) of the burner 40 are operated (or after the preheating burner 60 is operated), and at the same time, the burner 40 is operated. Then, combustion in the burner 40 is performed using the combustion air heated by the preheating burner 60.

  When the burner 40 according to this embodiment is operated in a low combustion state, first, a blower (not shown) is driven, and air is supplied to the first air supply path 43 and the second air supply path 45 via the wind box 100. Is done. As described above, the air supplied in this manner is air heated by the preheating burner 60, and specifically, air A (high temperature) heated by the preheating burner 60 in the air preheating region 44. Air) is supplied to the second air supply path 45. Further, since the flame is formed in the preheating burner 60, naturally, the air supplied from the first air supply path 43 adjacent to the air preheating region 44 is also heated high-temperature air. . Next, the igniter 41 is energized in accordance with the timing at which the liquid fuel is sprayed from the first nozzle portion 42a.

  In the present embodiment, air (hot air) is ejected from the central air ejection portion 46 and the ambient air ejection portion 47 via the first air supply path 43 and the second air supply path 45, and this air and the first nozzle Mixing with the liquid fuel sprayed from the part 42a is performed. Then, the liquid fuel mixed with air is ignited by an igniter 41 provided near the first nozzle portion 42a to form an electric spark when energized. By this ignition, the liquid fuel sprayed from the first nozzle part 42a burns, and the low combustion state is maintained as long as the liquid fuel continues to be sprayed from the first nozzle part 42a. Moreover, if liquid fuel is supplied also from the 2nd nozzle part 42b with the 1st nozzle part 42a, the burner 40 will be in a high combustion state.

  In the burner 40 according to the present embodiment, the fuel supply state in the nozzle portion 42 is appropriately switched (on / off control), and can be switched to any one of the stopped state, the low combustion state, and the high combustion state. That is, when the combustion state continues, switching from low combustion to high combustion or from high combustion to low combustion is possible. As a matter of course, when the burner 40 is in a stopped state, the preheating burner 60 is also in a stopped state.

  The amount of air supplied to the burner 40 is generally adjusted using a damper (not shown) provided in a duct between the wind box 100 and the blower, an inverter for controlling the rotational speed of the blower, or the like (not shown). The And this air is supplied corresponding to the supply amount of liquid fuel. For example, in a burner configured using two nozzle tips having similar fuel supply performance, the amount of air supplied when liquid fuel is sprayed from one of the nozzle tips (at the time of low combustion) is “1”. Then, the amount of air supplied when spraying liquid fuel from both nozzle tips (during high combustion) is set to “2”. Such air amount adjustment is performed using a damper or an inverter.

  In the combustion apparatus (burner 40 and preheating burner 60) configured and functioning as described above, combustion air A or the like heated by the preheating burner 60 is introduced into the burner 40 as shown in FIG. The combustion in the burner 40 is performed using the fuel air A. The burner 40 is provided with a guide portion 58 so that air from the ambient air ejection portion 47 is ejected inward, so that the introduced high-temperature combustion air A is ejected from the nozzle portion 42 and the liquid fuel. By mixing, in the burner 40, a flame F (combustion gas) (not shown) is formed in a downward direction in a state where the spread is suppressed.

  The combustion gas G0 generated by the burner 40 flows downward along the inner water tube group 20. The gas that has flowed downward along the inner water tube group 20 collides with the lower surface of the can body 10, and then becomes a flow of gas G1 (see FIGS. 1 and 2) that flows radially in the circumferential direction. It is introduced into the annular gas flow path 80 through the inner gas flow path 25.

  The gas G <b> 2 introduced into the annular gas channel 80 via the inner gas channel 25 then flows upward along the inner water tube group 20 and the outer water tube group 30. At this time, the gas G2 flows upward while turning according to the inclination angle of the flat fins (the first fin 23 and the second fin 33) provided in the inner water tube group 20 and the outer water tube group 30. To do. Then, the gas G2 that has flowed upward while swirling collides with the upper surface of the can body 10, and then becomes a flow of gas G3 (see FIGS. 1 and 4) that flows radially in the circumferential direction. The gas is collected in the exhaust cylinder 90 via the gas flow path 35 and discharged to the outside of the can body 10 via the exhaust cylinder 90.

  In the gas flow as described above, the thermal energy of the flame (combustion gas) generated by the burner 40 is recovered by the inner water tube group 20 and the outer water tube group 30.

  More specifically, first, the gases G0 and G1 and the inner surface of the inner water tube group 20 are in contact with each other on the inner surface side of the inner water tube group 20 (the side where the burner 40 is provided (combustion chamber side)). The heat recovery is performed by Next, when the gas G1 passes through the inner gas flow path 25, the inner water pipe group 20 (the lower end portion 21a of the inner water pipe 21) and the first stud fins 22 provided in the vicinity of the inner gas flow path 25, Heat recovery is performed by contact with the gas G1.

  Next, after the gas G1 passes through the inner gas passage 25, the gas collides with the lower end of the outer water tube group 30, and in addition, stud fins 22 and 32 are provided in the vicinity of the inner gas passage 25. Therefore, a turbulent state is promoted in the vicinity of the inner gas flow path 25. Therefore, in the vicinity of the inner gas flow path 25, the first stud fins 22 and the second stud fins 32 are effectively brought into contact with the gas, and highly efficient heat recovery is performed.

  Next, the gas G2 flowing upward while swirling in the annular gas flow path 80 is supplied to the inner water tube group 20, the outer water tube group 30, and the flat fins (first fins) provided in each of the water tube groups 20, 30. 23, the second fin 33) is contacted, and heat recovery from the gas G2 is performed by making these contacts. Finally, the gas G3 that has flowed upward while swirling through the annular gas channel 80 is collected outside the outer tube group 30 (exhaust tube 90 side) until it is collected in the exhaust tube 90 via the outer gas channel 35. ), The heat recovery is performed.

  Since the combustion apparatus (burner 40, preheating burner 60) and boiler 1 according to this embodiment are configured and function as described above, the following effects can be obtained.

  In the present embodiment, the preheating burner 60 (corresponding to the “preheating portion” of the present invention) is provided on the upstream side of the burner 40 as described above, and the combustion air A heated by the preheating burner 60 is used. Combustion in the burner 40 is performed. That is, the burner 40 is supplied with combustion air A having a high temperature and a low oxygen concentration. Therefore, according to such a configuration, the combustion air A having a low oxygen concentration is supplied to the liquid fuel ejected from the nozzle portion 42 (corresponding to the “fuel ejection portion” of the present invention). NOx conversion can be achieved. In addition, since the high-temperature combustion air A is supplied, vaporization combustion (fuel vaporization) of the liquid fuel is promoted, and low dust, low CO, and low NOx can be achieved. That is, according to this embodiment, it is possible to reduce harmful substances.

  In the present embodiment, a preheating burner 60 is provided on the upstream side of the plurality of ambient air ejection portions 47 (corresponding to the “air ejection portion” of the present invention) corresponding to each ambient air ejection portion 47. Since it is provided, high-temperature combustion air can be supplied to the burner 40 in a well-balanced manner. Therefore, according to such a structure, the combustion apparatus which can maintain the stable combustion state can be obtained. More specifically, in the present embodiment, one is provided above each of the surrounding air ejection portions 47 provided on the circumference of the nozzle portion 42 (provided on the circumference around the nozzle portion 42). Since each preheating burner 60 is provided, high-temperature combustion air can be supplied in a more balanced manner.

  Furthermore, according to the present embodiment, since the ambient air ejection part 47 has the guide part 58, the flow of the flame (gas) is controlled in accordance with the configuration of the can body (position of the gas flow path, etc.) Reduction (low dust, low NOx) can be achieved. In the present embodiment, the inner gas flow path 25 of the can body 10 is formed in an annular shape below, and the gas flows uniformly to the inner gas flow path 25 and the gas to the inner water tube group 20 is In order to eliminate early contact, the guide portion 58 is provided at an angle at which combustion air is ejected inward (nozzle portion 42 side). If the combustion air is ejected inward based on such a configuration, the liquid fuel and the flame (gas) at the combustion start stage are less likely to come into contact with the inner water tube group 20 of the can 10. Inappropriate incomplete combustion can be eliminated, and generation of CO and soot can be effectively prevented.

  Moreover, according to such a structure, since the some surrounding air ejection part 47 is provided in the circumference | surroundings of the nozzle part 42, a division | segmentation flame can be formed and reduction in NOx can be achieved.

  Furthermore, according to such a configuration, by having the guide portion 58, it becomes possible to focus the combustion air and bring it into contact with the liquid fuel at a high speed, so that the combustion state of the flame approaches vaporization combustion, Low NOx can be achieved. Further, by increasing the flow velocity of the combustion air jetted by providing the guide portion 58 in this way, the gas around the guide portion 58 is entrained (because it is in a state of self-recirculation), so the NOx is reduced. Can be achieved.

  Moreover, the surrounding air ejection part 47 which comprises the burner 40 concerning a present Example also has the spreading | diffusion part 59 with the guide part 58 which exhibits the various effect mentioned above. As described above, the diffusion portion 59 is a portion of the through-hole portion 51 that is not covered with the guide portion 58 (see FIGS. 5 and 6). That is, since the diffusion part 59 is not provided with an element for rectifying the air, such as the guide part 58, the air ejected from the diffusion part 59 flows into the edge part (through-hole part) of the diffusion part 59. 51 (edge portion)). Then, in the immediate vicinity of the burner 40, a small turbulence occurs in the air, and the mixing state of the liquid fuel sprayed from the nozzle part 42 and the air can be partially made uneven. Since the burner 40 according to the present embodiment has such a diffusing portion 59, the mixing state is not simply improved, and a partly intentionally non-uniform mixing state can be formed. That is, in the present embodiment, by providing the diffusing portion 59, it is possible to form a light and dark combustion state in the vicinity of the burner 40, so that the gas temperature can be lowered and the NOx value can be reduced. Of course, according to such a configuration, since the ambient air ejection part 47 has the diffusion part 59, the liquid fuel and the combustion air can be effectively mixed to reduce dust.

  As described above, the boiler 1 (combustion device constituting the boiler 1) according to the present embodiment has the preheating burner 60 on the upstream side of the burner 40, so that the combustion air A having a high temperature and a low oxygen concentration is present. By being supplied to the burner 40, NOx reduction, CO reduction, dust reduction, and the like can be achieved. According to the boiler 1 according to the present embodiment, low dust combustion is possible in this way, and therefore the can 10 constituting the boiler 1 can be downsized.

  Further, the boiler 1 according to the present embodiment is configured to reduce the CO and dust by suppressing the spread of the gas in the combustion chamber 16 of the can body 10, and the gas temperature by the appropriate exhaust gas circulation flow formed in the can body 10. NOx reduction, CO reduction, dust reduction, etc. due to the synergistic effect of reduction, gas temperature reduction due to the formation of an appropriate divided flame, and gas temperature reduction due to concentration combustion formed by the diffusion part 39 Can be achieved.

  Furthermore, according to the present embodiment, the boiler 1 is configured as described above, and the gas flows in the can 10 as described above. Therefore, heat recovery is effectively performed and an extended transmission with high durability. A boiler having a water tube group having a hot surface (such as fins) can be obtained.

  Specifically, according to the boiler 1 according to the present embodiment, the stud fins 22 and 32 (enlarged heat transfer surfaces) are provided in the vicinity of the inner gas channel 25 (gas channel), which is a region where the temperature difference is large. Therefore, heat recovery can be performed effectively. In addition, since the enlarged heat transfer surfaces provided in the vicinity of the inner gas flow path 25 are the stud fins 22 and 32, even if an overheated state occurs, cracks, dropouts, and the like are unlikely to occur. Further, according to such a configuration, the stud fins 22 and 32 are provided in the vicinity of the inner gas flow path 25, and heat recovery is performed from the combustion gas at an early stage, and the temperature of the combustion gas is lowered early. Can be reduced.

  Further, in the boiler 1 according to the present embodiment, flat fins 23 and 33 inclined with respect to the gas flow are provided on the downstream side of the stud fins 22 and 32 provided in the vicinity of the inner gas flow path 25. It has been. According to such a configuration, it becomes possible to configure the boiler 1 that can be recovered more effectively and operated with high efficiency without wasting the heat energy that could not be recovered by the stud fins 22 and 32. .

  Furthermore, in the boiler 1 according to the present embodiment, the plate-like fins 23 and 33 provided on the downstream side of the stud fins 22 and 32 are provided so as to be inclined at a predetermined angle with respect to the gas flow. Ascending while rotating in the annular gas flow path 80. That is, according to the present embodiment, compared to the case where fins are provided at right angles to the gas flow, the fins 23 and 33 do not obstruct the gas flow, so that the boiler 1 capable of realizing a low pressure loss can be obtained. .

  Moreover, according to the boiler 1 concerning a present Example, since it becomes possible to implement heat recovery effectively as mentioned above, it becomes possible to achieve size reduction of a boiler resulting from this. . That is, by increasing the heat recovery rate, it is possible to increase the operating efficiency of the boiler, and accordingly, the boiler can be reduced in size.

<Other examples>
The present invention is not limited to the above-described embodiments and examples (hereinafter referred to as “the above-described embodiments and the like”), and various modifications are made as necessary within the scope that can meet the gist of the present invention. These are all included in the technical scope of the present invention.

  In the above-described embodiment and the like, the configuration in which the preheating burner 60 (corresponding to the “preheating portion” of the present invention) is provided in the windbox 100 has been described. However, the present invention is not limited to this configuration, and the preheating according to the present invention. The position where the portion is provided is not particularly limited as long as it is upstream of the nozzle portion 42 (corresponding to the “fuel injection portion” of the present invention). Therefore, for example, a preheating part may be provided in the air duct 101. Or you may provide in the upstream (or downstream side (the above-mentioned embodiment etc. are contained in this)) of a fan.

  Further, in the above-described embodiments and the like, the case where the six preheating burners 60 are used as the preheating unit has been described, but the present invention is not limited to this configuration, and any number of preheating burners may be provided. Although the number of preheating burners 60 preferably corresponds to the number of ambient air ejection portions 47 as in the above-described embodiment, the present invention is not limited to this configuration, and the ambient air ejection is performed as necessary. You may comprise a preheating part using the preheating burner of less than the number of parts. Thus, when using a preheating burner with less than the number of surrounding air ejection parts, it is preferable to provide an appropriately branched air supply path downstream of the preheating burner (preheating part) so that high-temperature air is supplied in a well-balanced manner. .

  Furthermore, in the above-described embodiments and the like, the description has been given of the case where the guide portions 58 provided in the respective surrounding air ejection portions 47 are provided in the same direction (inward direction) and inclined at the same angle. Is not limited to this configuration. Therefore, for example, you may comprise so that the installation inclination angle of each guide part 58 may differ suitably.

  In the above-described embodiment, etc., the case where the guide portion 58 is configured using a plate-shaped member (scoop type) having a U-shaped cross section has been described, but the present invention is not limited to this configuration, Any configuration may be employed as long as at least a part of the air ejected from the air ejection portion 47 can be guided inward. Therefore, you may comprise a guide part using the flat plate-shaped member of 1 sheet, for example. Specifically, a flat plate-like member may be provided on the outer peripheral portion of the through-hole portion 51 constituting each of the surrounding air ejection portions 47 so as to be inclined. Even with such a configuration, it is possible to guide at least part of the air ejected from the ambient air ejecting portion 47 in the inner direction, and thus the various effects described above can be obtained.

  Furthermore, in the above-described embodiment, the second nozzle 42b for high combustion is disposed on the central axis of the first cylindrical member 53, and the first nozzle 42a for low combustion (and high combustion) is disposed from the central axis. Although the arrangement is shifted, the present invention is not limited to this arrangement. For example, the center between the second nozzle 42 b and the first nozzle 42 a can be arranged so as to overlap the central axis of the first cylindrical member 53. The present invention can also be applied to a burner that switches between a low combustion amount and a high combustion amount by a single nozzle (not shown).

  Moreover, in the said embodiment etc., although the case where the guide part 58 was provided in all the surrounding air ejection parts 47 was demonstrated, this invention is not limited to this structure. The present invention aims to control the flow of air (combustion air) so that the gas generated by the burner 40 does not spread outside more than necessary. In addition to the configuration in which the guide portion is provided, the concept includes a configuration in which the guide portion is provided in part of the ambient air ejection portion.

  Furthermore, in the above-described embodiments and the like, the type of liquid fuel was not particularly described, but the present invention is not limited to any liquid fuel, and liquid fuels such as kerosene, A heavy oil, B heavy oil, and C heavy oil are used. Applicable. Moreover, in the said embodiment etc., although the case where liquid fuel was used as a fuel was demonstrated, this invention is not limited to this structure, You may use gaseous fuel as needed. Furthermore, for example, a two-component mixed fluid (for example, a fluid obtained by mixing liquid fuel and water) may be used as the fuel.

  Moreover, the boiler 1 concerning this invention is not limited to the structure of the can 10 demonstrated in FIG. 1 etc., A various change is possible as needed. Therefore, for example, a configuration as shown in FIG. 9 may be adopted. Here, FIG. 9 shows a simplified explanatory view of a transverse section of a boiler according to another embodiment of the present invention.

  A boiler according to another embodiment has the same basic configuration as that of the first embodiment described above. Therefore, in the following, the same parts as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the detailed description thereof is omitted, and the configuration different from the first embodiment will be mainly described. .

  FIG. 9 is a simplified explanatory view of a cross section of a boiler according to another embodiment of the present invention. More specifically, it is a simplified explanatory diagram corresponding to FIG. 2 according to the first embodiment described above. That is, FIG. 9 shows a simplified explanatory view of a transverse section in the vicinity of the inner gas flow path 25 of the boiler according to the present embodiment.

  As described above, the boiler 1 according to the present embodiment basically has the same configuration as that of the first embodiment, and the difference from the first embodiment is that the inner gas flow path 25 is in the vicinity. The number of stud fins 22 and 32 provided. In this embodiment, compared with the first embodiment, the first stud fins 22 provided at the lower end 21a of the inner water pipe 21 are reduced, and the second stud fins 32 provided at the lower end of the outer water pipe 31 are provided. Many are provided. More specifically, the first stud fin 22 is not provided on the annular gas flow path 80 side at the lower end 21 of the inner water pipe 21, and the corresponding amount of the stud fin (reduced by the inner water pipe 21) is provided on the outer water pipe 31. It is provided at the lower end.

  As described in the first embodiment, after the gas G <b> 1 passes through the inner gas passage 25, the gas collides with the lower end portion of the outer water tube group 30. After that, in the vicinity of the inner gas flow path 25, the gas mainly flows upward along the outer water tube group 30. As a result, in the vicinity of the inner gas flow path 25, the outer water tube group 30 has more contact times with the gas than the inner water tube group 20.

  A present Example is comprised paying attention to this gas flow, and aims at providing the boiler 1 which can perform heat recovery with higher efficiency.

  As described above, the boiler according to the present embodiment is provided with the stud fins 22 and 32 in the inner water tube group 20 and the outer water tube group 30 in the vicinity of the inner gas flow path 25, and the outer water tube group 30 is arranged on the inner side. It is characterized by having a structure in which more stud fins are provided than in the water tube group 20.

  According to the boiler 1 according to the present embodiment, after the combustion gas generated in the burner 40 provided in the central portion of the inner water tube group 20 contacts the outer water tube group 30 via the inner gas passage 25, It circulates between water pipe groups (between the inner water pipe group 20 and the outer water pipe group 30) (annular gas flow path 80). At this time, the gas continuously flows from the inner water tube group 20 toward the outer water tube group 30, so in the annular gas flow path 80, the gas contact time is inevitably higher in the outer water tube group 30 than in the inner water tube group 20. Will be longer. According to the present embodiment, the outer water tube group 30 is provided with more stud fins than the inner water tube group 20, and therefore heat recovery from the combustion gas can be performed more effectively.

  Moreover, according to the boiler 1 concerning this other Example, in addition to the said effect, the effect obtained in a 1st Example can also be naturally obtained.

  Further, in the above-described embodiment and the like, the case where the stud fins 22 and 32 are provided in both the inner water tube group 20 and the outer water tube group 30 in the vicinity of the inner gas channel 25 (gas channel) has been described. It is not limited to the configuration. Therefore, for example, it is good also as a structure which provides a stud fin only in the outer side water pipe group 30 in the inner side gas flow path 25 vicinity. As described above, since the gas continuously flows from the inner water tube group 20 toward the outer water tube group 30, the gas contact time in the annular gas flow path 80 is longer than that of the inner water tube group 20. Will be longer. Therefore, even when the stud fin is provided only in the outer water tube group 30 in the vicinity of the inner gas flow path 25 in this way, heat recovery from the combustion gas can be performed relatively effectively.

  Moreover, in the said embodiment etc., although the structure which provides the cyclic | annular inner side gas flow path 25 (gas flow path) in the lower end side of the inner side water pipe group was demonstrated, this invention is not limited to this structure. Therefore, for example, an annular inner gas channel (corresponding to the “gas channel” of the present invention) may be provided on the upper end side of the inner water tube group. At this time, when the inner gas channel is provided on the upper end side of the inner water tube group, the outer gas channel is arranged on the outer side in order to increase the heat recovery rate (in order to increase the contact time between the gas and the water tube group). It is preferable to provide at the lower end side of the water tube group.

  Furthermore, in the above-described embodiment and the like, the case where a boiler is configured using a can body in which two rows of water pipe groups are arranged substantially concentrically has been described, but the present invention is not limited to this configuration, and as necessary. In addition, the can body may be configured by arranging three or more groups of water tubes. If a can body is configured by arranging three rows of water tube groups (for example, an inner water tube group, an intermediate water tube group, and an outer water tube group) in a substantially concentric circle, one end side (for example, the lower end side) of the inner water tube group If the inner gas flow path is provided in the intermediate water pipe group, the intermediate gas flow path is provided on the other end side (for example, the upper end side), and the outer gas flow is provided on one end side (for example, the lower end side) of the outer water pipe group. It is preferable to do.

  Moreover, in the said embodiment etc., although the case where the cylindrical stud fins 22 and 32 were used was demonstrated, this invention is not limited to this structure, The durable protrusion which can be welded appropriately to a water pipe Any shape may be used as long as it is a thing. Therefore, for example, an oblique cylinder shape, an elliptic cylinder shape (including an oblique elliptic cylinder shape), a prismatic shape (including an oblique prism shape), a cone shape (including an oblique cone shape), a pyramid shape (including an oblique pyramid shape), etc. Stud fins having the following shape may be used.

It is explanatory drawing of the longitudinal cross-section of the boiler concerning the 1st Example of this invention. FIG. 2 is a simplified explanatory diagram of a cross section taken along line II-II in FIG. 1. FIG. 3 is a simplified explanatory diagram of a cross section taken along line III-III in FIG. 1. FIG. 4 is a simplified explanatory diagram of a cross section taken along line IV-IV in FIG. 1. It is explanatory drawing of the longitudinal cross-section of the wind box and combustion apparatus concerning 1st Example of this invention. FIG. 6 is a bottom view of the wind box and the combustion apparatus shown in FIG. 5. It is the schematic of the VII-VII arrow line direction of FIG. It is explanatory drawing of the longitudinal cross-section of the preheating burner which comprises the combustion apparatus concerning the 1st Example of this invention. It is a simplified explanatory drawing of the cross section of the boiler concerning the other Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Boiler 10 ... Can body 11 ... Upper header 12 ... Lower header 16 ... Combustion chamber 20 ... Inner water pipe group 21 ... Inner water pipe 21a ... Lower end part 22 ... First stud fin 23 ... First fin (flat fin)
24 ... First vertical fin part 25 ... Inner gas flow path 30 ... Outer water pipe group 31 ... Outer water pipe 31a ... Upper end part 32 ... Second stud fin 33 ... Second fin (flat fin)
34 ... Second vertical fin part 35 ... Outer gas flow path 40 ... Burner 41 ... Igniter 42 ... Nozzle part 42a ... First nozzle part 42b ... Second nozzle part 43 ... First air supply path 44 ... Air preheating region 45 ... 2nd air supply path 46 ... Central air ejection part 47 ... Ambient air ejection part 47a-47f ... 1st ambient air ejection part-6th ambient air ejection part 51 ... Through-hole part 51a-51f ... 1st through-hole part-1st Six through-hole parts 53 ... 1st cylinder member 54 ... Air preheating cylinder member 55 ... 2nd cylinder member 56 ... 1st air supply plate 57 ... 2nd air supply plate 58 ... Guide part 58a-58f ... 1st guide part-1st Six guide parts 59 ... Diffusion part 59a-59f ... First diffusion part-Sixth diffusion part 60 ... Preheating burner 60A-60F ... First preheating burner-Sixth preheating burner 61 ... Preheating igniter 61A-61F ... First preheating ignition -6th preheating igniter 62 ... Preheating nozzle part 62A-62F ... 1st preheating nozzle part-6th preheating nozzle part 63 ... Preheating burner cylinder member 63A-63F ... 1st preheating burner cylinder member-6th preheating burner cylinder member 64 ... Preheating flame holding part 64A -64F ... 1st preheating flame holding part-6th preheating flame holding part 65 ... Air supply hole part 80 ... Annular gas flow path 90 ... Exhaust pipe 100 ... Wind box 101 ... Air blow duct

Claims (6)

A combustion apparatus comprising a fuel ejection portion that ejects at least one of liquid fuel and gaseous fuel, and an air ejection portion that ejects combustion air,
A combustion apparatus comprising a preheating part upstream of the air ejection part. Around the fuel ejection part, a plurality of the air ejection parts for ejecting combustion air are provided,
2. The combustion apparatus according to claim 1, wherein the preheating unit is provided on the upstream side of the air ejection unit so as to correspond to each of the air ejection units. The combustion apparatus according to claim 1 or 2, wherein the preheating unit is configured by using one or more preheating burners for ejecting the fuel. 4. The combustion apparatus according to claim 3, wherein each of the preheating burners is disposed on a circumference centering on the fuel ejection portion, corresponding to the air ejection portion. A plurality of the air ejection portions that eject combustion air are provided around the fuel ejection portion,
The combustion apparatus according to any one of claims 1 to 4, wherein each of the air ejection portions includes a guide portion that controls an air ejection direction and a diffusion portion that diffuses the ejected air. A boiler comprising a can having an inner water tube group and an outer water tube group arranged in an annular shape, and a combustion device capable of burning at least one of liquid fuel and gaseous fuel in the can,
The said combustion apparatus is a combustion apparatus of any one of Claim 1 to 5, The boiler characterized by the above-mentioned.

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