JP2007071527A - Boiler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boiler capable of realizing reduction of harmful matter such as NOx. <P>SOLUTION: The boiler is provided with a body 10 composed by using a plurality of water pipes, and a burner 20 arranged in an upper part of the body 10, and a gas exhaust port 17 of a combustion chamber 16 is provided in a combustion chamber 16 side face. An outflow suppressing means 18 is provided for suppressing gas discharged from the burner 20 from taking a shortcut from a burner 20 neighborhood part of the gas exhaust port 17 and flowing out by spacing the turner 20 and the gas exhaust port 17. The outflow suppressing means blocks an upper part of the gas exhaust port 17. The gas exhaust port 17 is formed biased in the combustion chamber side face. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a boiler. More specifically, the present invention relates to a boiler capable of reducing harmful substances using fuel such as kerosene and A heavy oil.

  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. . In other words, in the boiler having such a configuration, the inner side of the annular water tube group functions as a combustion chamber for burning the fuel supplied from the burner.

  In such boilers, many proposals have been made regarding technologies for improving combustibility and technologies for reducing harmful substances (NOx, CO, soot, etc.) (see, for example, Patent Document 1).

  By the way, in the boiler comprised using the can which has the water pipe group arranged in the above-mentioned ring shape, like the ω flow can, the gas discharge port of the combustion chamber is in one place in the circumferential direction on the side of the combustion chamber. In the can body provided in a biased manner, the gas ejected from the burner tends to be pulled in a specific direction (mainly the direction in which the gas discharge port is provided), that is, not axially symmetric. For this reason, the gas during the combustion reaction from the burner contacts the inner surface of the can body, and the gas ejected from the burner flows out from the vicinity of the burner at the gas outlet through a short path, thereby adversely affecting the combustion performance of the burner. In addition, it has been difficult to reduce the amount of exhausted NOx.

JP-A-8-61614

  Therefore, the present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a boiler that can reduce harmful substances such as NOx.

  The present invention has been made to solve the above-mentioned problems, and the invention according to claim 1 is a can body configured by using a plurality of water pipes, and a burner disposed above the can body. A gas exhaust port of the combustion chamber provided on a side surface of the combustion chamber, the gas ejected from the burner by separating the burner and the gas exhaust port from the gas exhaust port The present invention is characterized in that it is provided with outflow suppression means that suppresses a short path from flowing out of the vicinity of the burner.

  The invention according to claim 2 is characterized in that, in claim 1, the burner and the gas discharge port are separated by closing the upper portion of the gas discharge port.

  According to a third aspect of the present invention, in the second aspect of the present invention, in the second aspect, a water pipe having a reduced diameter is provided at the gas outlet, and the upper part of the water pipe and an adjacent water pipe are brought into contact with each other, whereby the gas outlet It is characterized by closing the upper part of.

According to a fourth aspect of the present invention, in the first aspect, the can body includes an inner water tube group in which a large number of water tubes are annularly arranged, and an outer water tube group in which a large number of water tubes are disposed outside the inner water tube group. A water tube facing the gas discharge port among the water tubes of the inner water tube group, wherein the inner water tube group has a combustion chamber inside and a gas discharge port of the combustion chamber is provided on a side surface of the inner water tube group. And the upper portion of the passage between the water pipe adjacent to the water pipe and the water pipe of the outer water pipe group, and the lower part functions as a gas outlet, thereby substantially separating the burner and the gas outlet. It is characterized by letting.

  A fifth aspect of the present invention is characterized in that, in any of the first to fourth aspects, the gas discharge port is formed in a biased manner on a side surface of the combustion chamber.

  The invention described in claim 6 is characterized in that, in claim 5, gas flow control means for controlling the flow of gas formed by the burner in a direction away from the gas discharge port is provided.

  A seventh aspect of the present invention is that, in the sixth aspect, the gas flow control means is a plurality of air nozzles for ejecting secondary air provided around the nozzles of the burner at the tip of the burner. It is characterized by.

  Furthermore, the invention described in claim 8 is characterized in that, in any one of claims 1 to 7, the burner is a self-recirculation type burner.

According to the present invention, it is possible to suppress the deterioration of combustibility due to the gas generated by the burner flowing out from the gas outlet through a short path, and to obtain a boiler capable of reducing harmful substances such as NOx. it can.

  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.

  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.

(Embodiment 1)
First, the boiler according to the first embodiment includes a can body configured by using a plurality of water pipes, and a burner disposed at an upper portion of the can body, and a gas discharge port of the combustion chamber is provided on a side surface of the combustion chamber. The provided boiler, wherein the gas ejected from the burner is prevented from flowing out in a short path from the vicinity of the burner of the gas discharge port by separating the burner and the gas discharge port. It is characterized by having outflow suppression means. That is, the burner and the gas discharge port are separated from each other by a predetermined distance so as to prevent the gas ejected from the burner from flowing out of the gas discharge port in the vicinity of the burner through a short path. ing.

According to such a configuration, the outflow suppressing means suppresses the gas ejected from the burner from flowing out in a short path from the vicinity of the burner at the gas discharge port, thereby improving the burner combustion performance. To reduce harmful substances. That is, the suppression of the short path suppresses the drift of gas from the burner, so that the self-recirculation flow in the vicinity of the burner is improved, and the self-recirculation gas flows uniformly. Droplet pre-evaporation and pre-mixing are performed uniformly. As a result, pre-evaporation and premixing can suppress the generation of local low air ratio and high temperature fields, leading to low NOx. Even in the case of gas fuel, since the self-recirculation gas flows uniformly, the generation of a local low air ratio / high temperature field can be suppressed, leading to low NOx. In addition, since a gas show path flowing out from the gas discharge port is suppressed, discharge of unburned components such as CO and dust (smoke) can be suppressed. In addition, low NOx and suppression of unburned components can be achieved without changing the structure of the burner.

  Next, each component of the first embodiment will be described. The first embodiment is preferably implemented in a can called a ω flow. The reason for this is that the effect of the outflow suppression means is great because there is only one gas outlet in the combustion chamber and the gas drift from the burner is relatively remarkable. The ω flow can body includes an inner water tube group (inner water tube wall) in which a large number of water tubes are arranged in an annular shape, and an outer water tube group (outer water tube wall) in which a large number of water tubes are arranged outside the inner water tube group. A combustion chamber is provided inside the inner water tube wall, and a first gas discharge port of the combustion chamber is provided at one place on the side surface of the inner water tube wall. Provide two gas outlets. In this can body, the gas flows out of the combustion chamber from the first gas discharge port, flows in two directions in an annular gas passage between the inner water tube wall and the outer water tube wall, It merges at the second gas discharge port and flows out of the can body.

  However, the can body is not limited to the ω flow can body, and the can body that is easy to flow out by short-passing from the vicinity of the burner of the gas discharge port formed on the side of the combustion chamber, the gas ejected from the burner, The all-outlet type can body and the gas discharge port of the combustion chamber include can bodies other than the ω flow can body formed at a plurality of locations on the side surface of the combustion chamber. Here, the fact that the gas discharge ports are formed unevenly means that the gas does not flow out almost uniformly from the entire side surface of the combustion chamber, but the gas flows out only from a specific position in the circumferential direction of the side surface of the combustion chamber. This means that the gas discharge port is formed at a specific position.

The burner is a premixed burner, preferably a self-recirculating burner. This self-recirculating burner is a system in which a gas having a low oxygen concentration in the combustion chamber is drawn into the burner base by the air blown from the secondary air jet formed around the fuel nozzle and mixed with the combustion air. This type of burner suppresses NOx production. By combining this self-recirculation type burner and the outflow suppression means, not only the effect of reducing CO and dust, but also a remarkable effect in reducing NOx due to the improvement effect of the self-recirculation flow is achieved. .

  The self-recirculating burner preferably has a first cylindrical member having an opening on the downstream side of the fuel supply, accommodating the tip of the nozzle portion, and forming a central air ejection portion on the downstream end surface, It is arranged on the outer peripheral side of the first cylinder member, and includes a second cylinder member in which an ambient air ejection portion is formed on the downstream end face. Further, the self-recirculation burner employed in this embodiment is more preferably formed by forming 4 to 12 surrounding air ejection portions (secondary air ejection ports) at intervals in the circumferential direction. And

The nozzle part is composed of a first nozzle part for spraying fuel during low combustion and high combustion and a second nozzle part for spraying fuel only during high combustion, so that the spray amount is adjusted by one nozzle part. Can be configured. The central axis of the nozzle portion is preferably biased toward the anti-gas outlet side (in a direction away from the gas outlet) with respect to the central axis of the first cylinder member, that is, the central axis of the combustion chamber. Thereby, the gas from the said burner can be shifted to the whole anti-gas discharge port side, and the combustibility deterioration by providing the said gas discharge port biasing can be suppressed.

  The burner can be not only a liquid fuel combustion burner, but also a gas fuel burner or a switch-only combustion burner that switches between oil fuel and gas fuel for combustion.

  The outflow suppression means is configured to prevent the gas from the burner from passing through a short path (the gas ejected from the burner flows out from the vicinity of the burner of the gas discharge port without going to the bottom of the combustion chamber). And the gas discharge port upper end portion are separated by a predetermined distance. Since the flame formation start position of the burner is located in the vicinity of the lower end of the burner, the lower end of the burner can be set as the flame formation position.

  Further, as a first aspect of the outflow suppression means, preferably, when the gas discharge port is formed up to the lower end of the burner or near the flame formation start position, the upper portion of the gas discharge port is closed. A shielding means (blocking means) is provided. As a specific form of the shielding means, when the gas discharge port is formed as a gap between the water pipe and the water pipe, a shielding plate for shielding the upper end portion of the gap is used. The length of the shielding plate in the vertical direction is about 250 mm to 400 mm. In this aspect, the shielding part which has the function similar to the said shielding board can be comprised with the said water pipe by forming the upper part of a water pipe in flat shape. The shielding plate can form an opening in a part thereof so as not to impair the effect of suppressing the short path. Moreover, it can also consist of a plurality of shielding plates.

  In this first aspect, when the gas discharge port is wider than the outer diameter of one water pipe, one or a plurality of water pipes are arranged in the gas discharge port, and a gap between adjacent water pipes is formed in the gas discharge port. The upper portion of the gap can be closed with the shielding plate. The shielding plate is preferably a metal, but can be made of a refractory material such as castable. When using a castable, it can comprise so that the upper part of the said gas exhaust port may be filled up.

  Further, in such a configuration in which a water pipe is arranged at the gas discharge port, the water pipe is narrowed at the outer diameter of the lower part, and the upper part of the gas discharge port is closed by contacting the water pipe and the adjacent water pipe at the upper part. Accordingly, the burner and the gas discharge port can be configured to be separated from each other. In this case, gas flows out from a gap formed in the lower part between this water pipe and the adjacent water pipe, and functions as a gas outlet. According to such a configuration, since the width of the shielding plate can be reduced, deformation due to thermal stress of the shielding plate can be reduced, and the durability of the shielding plate can be improved.

  The second aspect of the outflow suppression means is as follows. The can body includes an inner water tube group in which a large number of water tubes are annularly arranged, and an outer water tube group in which a large number of water tubes are disposed outside the inner water tube group, and the inside of the inner water tube group serves as a combustion chamber. A gas discharge port of the combustion chamber is provided on a side surface of the inner water tube group, a water tube facing the gas discharge port among water tubes of the inner water tube group, and a water tube of the outer water tube group adjacent to the water tube; By closing the upper part of the passage between the burner and the gas discharge port, the burner and the gas discharge port are substantially separated. Here, “substantially separate the burner and the gas outlet” means that a gap formed between the water pipe of the inner water pipe group and the water pipe of the outer water pipe group functions as a gas outlet. Is meant to do.

In this second aspect, instead of providing a shielding plate at the gas discharge port, a shielding plate is provided between the water tube of the inner water tube group and the water tube of the outer water tube group, so that it is provided at the gas discharge port. In comparison, the amount of radiant heat from the combustion chamber received by the shielding plate can be reduced, and the durability of the shielding plate can be improved.

  Furthermore, as a third aspect of the outflow suppression means, the gas discharge port itself is formed at a position away from the burner by a predetermined distance instead of providing the shielding means. It is possible to have a configuration that suppresses a short path of gas. That is, when the gas discharge port is a can that is formed near the lower end of the burner or near the flame formation start position, the burner is displaced upward by the predetermined distance. Thereby, there can exist an effect similar to said 1st aspect. However, this second mode is inferior to the first mode in terms of the height of the can including the burner and the heat insulation between the flame formation start position of the burner and the water pipe.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. The second embodiment is a boiler characterized by comprising gas flow control means for controlling the flow of gas formed by the burner in a direction away from the gas discharge port in addition to the outflow suppression means. is there.

  According to such a configuration, the gas generated by the burner is configured not to be short-passed from the gas discharge port provided in the combustion chamber by the outflow suppression means, and the gas flow control is performed. By the means, the flow of gas formed by the burner is controlled in a direction away from the gas discharge port. By these two actions, it is possible to correct the gas drift due to the presence of the gas outlets in a biased manner, so that the combustion performance of the burner is further improved compared to the first embodiment, and harmful substances are reduced. Can be realized.

  The burner according to the second embodiment includes at least two aspects as the self-recirculating burner. In the burner of the first aspect, the air ejection part formed around the nozzle includes 6 to 8 air nozzles that guide the air ejected from the air ejection part in a direction away from the gas discharge port. It is said. These air nozzles are preferably formed in a rectangular tube shape, and the air ejection portion is formed by inclining all the air nozzles toward the anti-gas discharge port side on the constituent wall surface of the square tube on the gas discharge port side. Can be guided in a direction away from the gas discharge port. However, only the constituent wall surface of the air nozzle on the gas outlet side may be inclined toward the anti-gas outlet side. The air nozzle can be configured to guide the air ejected from the air ejection portion in a direction away from the gas exhaust port by inclining the nozzle itself.

  In the second aspect of the burner according to the second embodiment, the air ejection part includes a guide part that guides at least a part of the air ejected from the air ejection part in a direction away from the gas discharge port, and a guide part. And a diffusion part that promotes diffusion of air ejected from the air ejection part.

  According to such a configuration, since not only the guide part but also the diffusion part is provided, the mixing state of the fuel and air injected from the nozzle part may be partially non-uniform in the immediate vicinity of the burner. it can. That is, according to the burner having such a configuration, the mixing state is not simply made good, but the gas temperature is lowered by forming a partly intentionally non-uniform mixing state by the diffusion portion, and NOx. The value can be reduced.

The guide portion is configured by using a plate-like member provided on the gas discharge port side in the air discharge portion, and at least a part of the air discharged from the air discharge portion is moved away from the gas discharge port. The plate-like member is provided to be inclined so as to guide in the direction. That is, the burner having such a configuration is provided with the guide portion by a plate-like member so as to partially shield between the air ejection portion and the gas discharge port. Inclined on the opposite side.

  According to such a configuration, the guide portion can be configured relatively easily. In addition, by adjusting the size and attachment position of the plate-like member, not only the guide part but also the diffusion part described above can be configured easily. That is, a portion where the plate-like member is provided can function as a guide portion, and a part of the air ejection portion where the guide portion is not provided can function as a diffusion portion.

  The guide portion has a height set so that the liquid fuel ejected from the nozzle portion does not come into contact with the guide portion.

  According to such a configuration, since the liquid fuel does not contact the guide portion, inappropriate incomplete combustion in the immediate vicinity of the burner can be eliminated, and generation of CO and soot can be effectively prevented.

  Hereinafter, the boiler concerning Example 1 of the present invention is explained based on a drawing.

  FIG. 1 is a schematic diagram of a boiler according to a first embodiment of the present invention. Here, FIG. 1 shows an explanatory view of a longitudinal section of the boiler according to the first embodiment. Moreover, FIG. 2 has shown explanatory drawing of the cross section which follows the II-II line | wire of FIG. 3 and 4 are schematic views of a burner provided in the boiler according to the first embodiment. Here, FIG. 3 shows an explanatory view of a longitudinal section of the burner according to the first embodiment, and FIG. 4 shows a bottom view of the burner shown in FIG. FIG. 5 shows a schematic diagram of the combustion state (gas flow) of the boiler according to the first embodiment.

  As shown in FIGS. 1 and 2, the boiler 1 according to the first embodiment includes a can body 10 having a group of water tubes arranged in a ring, and a self-recirculation type disposed in the center of these water tube groups. A wind box 40 for supplying combustion air to the burner 20 is provided above the burner 20.

  The can body 10 is configured by standing a plurality of water pipe groups (an inner water pipe group 13 and an outer water pipe group 14) between an upper header 11 and a lower header 12. Each of the water tube groups 13 and 14 is arranged in a substantially concentric annular shape, and an outer water tube group 14 is provided at a predetermined interval from the inner water tube group 13, and between the inner water tube group 13 and the outer water tube group 14. An annular gas flow path 15 is formed at the end. Further, in the first embodiment, the inside of the annular water pipe groups 13 and 14 functions as the combustion chamber 16, and the burner 20 is provided above the combustion chamber 16. .

  In the first embodiment, the inner water tube group 13 includes an annular water tube wall in a state where the inner water tubes 13a are in close contact with each other or in a state where the adjacent inner water tubes 13a are connected by inner fin portions 13b. The gas discharge port 17 is provided in a part thereof. The gas discharge port 17 is opened along the longitudinal direction of the water pipe and functions to guide the gas generated in the combustion chamber 16 inside the inner water pipe group 13 to the annular gas flow path 15.

The upper portion of the gas discharge port 17 is closed by a shielding plate 18 corresponding to the shielding means of the present invention, and constitutes an outflow suppression means of the present invention. The gas discharge port 17 after closing from the lower end of the burner 20 (flame formation start position, in the first embodiment, a position near the tip of the air nozzle described later).
The distance from the upper end is about 400 mm. The shielding plate also functions as a heat exchange fin or fin.

  Further, the outer water pipe group 14 is formed in an annular shape with a substantially uniform predetermined interval between the outer water pipes 14a, and a gap between adjacent outer water pipes 14a is formed between the outer water pipes 14a. Outer fin portions 14b connected to be eliminated are provided. A part of the outer water tube group 14 is provided with an outer opening (second gas discharge port) 19, and the outer opening 19 allows a gas whose combustion reaction has been almost completed to flow outside the can body 10. Functions as a discharge unit for discharging. That is, the gas generated by the burner 20 is collected in the outer opening 19 and then discharged to the outside of the can body 10 through an exhaust pipe (not shown) provided at a position below the can body 10. .

  As shown in FIGS. 3 and 4, the burner 20 constituting the boiler 1 according to the first embodiment includes a partition wall 41 in a wind box 40 as air supply means for supplying combustion air to the burner 20. Is installed. Specifically, the mounting plate 21 constituting the burner 20 is mounted on the partition wall 41 from above, and the mounting plate 21 is fastened to the partition wall 41 by fastening means (not shown) such as bolts. The burner 20 is installed on a partition wall 41 in the wind box 40. In the first embodiment, the configuration of the blower that supplies air into the wind box 40 is a well-known technique and is omitted.

  As shown in FIGS. 3 and 4, the burner 20 according to the first embodiment includes a fuel nozzle portion 22 (first fuel nozzle portion 22 a and second fuel nozzle portion 22 b) that sprays liquid fuel, and the first fuel. An ignition insulator 23 provided so that its tip is positioned in the vicinity of the nozzle portion 22a, and air provided for mixing the air supplied from the window box 40 with the liquid fuel sprayed from the fuel nozzle portion 22. Supply path (first air supply path 24 for supplying primary air, second air supply path 25 for supplying secondary air) and air supplied from the first air supply path 24 are ejected to the combustion chamber 16 side. And a plurality of ambient air ejection portions 27 for ejecting the air supplied from the second air supply path 25 to the combustion chamber 16 side (the “air ejection portions in the first and second embodiments ( Serial air ejection portion provided on the periphery of the fuel nozzle 22) "considerable) (which is configured with a first ambient air injection unit 27a~ sixth ambient air ejection section 27f).

  The fuel nozzle part 22 according to the first embodiment includes a first fuel nozzle part 22a that sprays liquid fuel at the time of low combustion and high combustion, and a second fuel nozzle part 22b that sprays liquid fuel only at the time of high combustion. Is provided. That is, the fuel nozzle portion 22 includes a first fuel nozzle portion 22a that is in a fuel supply state during low combustion (and a high combustion time), and a second fuel that is in a fuel supply state together with the first fuel nozzle portion 22a during high combustion. The fuel supply state in each fuel nozzle part 22 is appropriately switched according to the combustion load of the boiler. That is, each nozzle part 22a, 22b is on / off controlled as necessary.

  The first air supply path 24 constituting the burner 20 is configured by using a first cylinder member 34 provided outside the fuel nozzle portion 22, and the second air supply path 25 is defined by the first air supply path 25. The cylindrical member 34 and the second cylindrical member 35 are used. That is, the inner area of the first cylinder member 34 functions as the first air supply path 24, and the area formed between the first cylinder member 34 and the second cylinder member 35 is the second air supply path. It functions as the path 25.

A first air supply plate 36 in which a central air ejection portion 26 is perforated is provided at the tip end portion (the end portion on the combustion chamber 16 side of the boiler 1) of the first cylindrical member 34, and is supplied from the wind box 40. The air thus discharged is ejected to the combustion chamber 16 side through the central air ejection portion 26. The second air supply plate is provided with a plurality (six in this embodiment) of the surrounding air ejection portions 27 at the tip end portion (the end portion on the combustion chamber 16 side of the boiler 1) of the second cylindrical member 37. 37 is provided, and the air supplied from the wind box 40 is ejected not only to the central air ejection portion 26 but also to the combustion chamber 16 side through the plurality of ambient air ejection portions 27.

  The ambient air ejection part 27 is provided around the fuel nozzle part 22 as shown in FIGS. And this ambient air ejection part 27 ejects from the said ambient air ejection part 27 so that the gas produced | generated in the said burner 20 may not carry out a short path | pass from the said gas exhaust port 17 provided in the said can 10. It is configured to control the flow of air.

  The ambient air ejection part 27 according to the first embodiment has at least a part of the air ejected from each ambient air ejection part 27 (the first ambient air ejection part 27a to the sixth ambient air ejection part 27f) as a gas outlet. The air nozzle 38 part (the 1st air nozzle part 38a-the 6th air nozzle part 38f) of the rectangular tube shape led to the direction away from 17 is provided.

  More specifically, in the first embodiment, six substantially trapezoidal through-hole portions 31 (first through-hole portion 31a to sixth through-hole portion 31f) are formed in the second air supply plate 37. The air nozzles 38 (first air nozzle 38 a to sixth air nozzle 38 f) are connected to the respective through-hole portions 31.

  Each air nozzle portion 38 is configured to guide the air ejected from each ambient air ejecting portion 27 in a direction away from the gas exhaust port 17, and the gas exhaust ports of the first air nozzle 38a to the sixth air nozzle portion 38f. The first cylinder constituting wall 39a to the sixth cylinder constituting wall 39f on the side close to 17 are inclined (inclined in the direction opposite to the gas discharge port 17 ("right side" in FIG. 3)). It is preferable that the inclination angle θ (attachment angle) of the first to sixth cylinder-constituting walls is about 5 ° to 30 °. Of course, the inclination angle θ is set so that the gas in the flame state does not contact the inner water pipe 13a.

  The boiler 1 concerning the present Example 1 is comprised as mentioned above, and has the following effects based on the structure. Hereinafter, in addition to FIGS. 1-4, FIG. 5 is used and the effect is demonstrated concretely. FIG. 5 is a schematic diagram showing the gas flow in the can during low combustion. In FIG. 5, the gas flow state diagram (gas F0) indicated by a two-dot chain line is different from the present embodiment in the burner structure, and the gas shape (flame shape) when the air from the burner is ejected in a substantially vertical manner. The gas flow state diagram (gas F1) indicated by the solid line shows the gas shape (flame shape) formed by the burner 20 according to the present embodiment.

  When the burner 20 according to the first embodiment is operated in a low combustion state, first, a blower (not shown) is driven, and the first air supply path 24 and the second air supply are supplied via the wind box 40. Air is supplied to the path 25. Next, the ignition insulator 23 is energized in accordance with the timing at which the liquid fuel is sprayed from the first fuel nozzle portion 22a.

That is, in the first embodiment, the air from the central air ejection part 26 and the ambient air ejection part 27, that is, the air nozzle part 38, via the first air supply path 24 and the second air supply path 25. The air is mixed with the liquid fuel sprayed from the first fuel nozzle portion 22a. Then, the liquid fuel mixed with air is ignited by the ignition insulator 23 which is provided near the first fuel nozzle portion 22a and forms an electric spark when energized. By this ignition, the liquid fuel sprayed from the first fuel nozzle portion 22a burns, and the low combustion state is maintained as long as the liquid fuel continues to be sprayed from the first fuel nozzle portion 22a. If the liquid fuel is supplied from the second fuel nozzle portion 22b together with the first fuel nozzle portion 22a, the burner 20 is in a high combustion state.

  In the burner 20 according to the first embodiment, the fuel supply state in the fuel nozzle portion 22 is appropriately switched (on / off control), so that it can be switched to a stopped state, a low combustion state, or a high combustion state. It is. That is, when the combustion state continues, switching from low combustion to high combustion or from high combustion to low combustion is possible.

  The amount of air supplied to the burner 20 is generally determined by using a damper (not shown) provided in a duct between the wind box 40 and the blower, an inverter for controlling the rotational speed of the blower, or the like (not shown). Adjusted. 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.

  Now, in the boiler 1 configured and functioning as described above, as shown in FIG. 5, when the burner 20 is in a low combustion state, the center of the combustion chamber 16 is substantially uniform in the can body 10. A gas F <b> 1 (solid line) that spreads out is formed. The gas F1 having such a shape is formed in the gas discharge port 17 so that the gas generated in the burner 20 from the gas discharge port 17 from the shielding plate 18 suppresses a short path. The peripheral air ejection part 27 provided around the nozzle part 22 is modified from the gas discharge port 17 provided in the can body 10 by devising the air nozzle part 38. This is because the flow of air ejected from the ambient air ejection section 27 can be controlled so that the gas generated by the burner 20 does not short-circuit.

  If the shielding plate 18 and the air nozzle portion 38 as in the first embodiment are not provided, the gas generated in the burner 20 is pulled to the gas discharge port 17 side, thereby The gas formed in the combustion chamber 16 is like a gas F0 indicated by a broken line in FIG. In other words, the conventionally known boiler is not provided with the shielding plate 18 and the air nozzle portion 38 for controlling the gas flow away from the gas discharge port 17 as shown in this embodiment. It is considered that the gas F0 having such a shape was formed in the combustion chamber 16. In such a case, the gas is pulled toward the gas discharge port 17 in the combustion chamber 16, so that problems such as hindering the exhaust gas circulation flow in the combustion chamber 16 occur.

  However, in the first embodiment, as described above, by providing the shielding plate 18 and the air nozzle portion 38, it is possible to form the gas F1 that spreads uniformly in the combustion chamber 16. Therefore, according to the first embodiment, the following effects can be obtained.

According to such a configuration, the gas generated in the burner 20 is prevented from being short-passed by the shielding plate 18 and the air nozzle portion 38 from the gas discharge port 17 provided in the combustion chamber 16. Therefore, the combustion performance of the burner 20 can be improved and the reduction of harmful substances can be realized. That is, the drift of the gas from the burner 20 is suppressed (the gas is suppressed from being pulled toward the gas discharge port 17), the self-recirculation flow in the vicinity of the burner 20 is improved, and the self-recirculation is uniformly performed. Gas flows in, pre-evaporation and pre-mixing are performed uniformly, and an appropriate split flame is formed. As a result, the pre-evaporation and premixing of the fuel droplets suppress the generation of a local low air ratio / high temperature field, and the formation of an appropriate split flame increases the surface area of the gas F1 and increases the gas temperature. descend. Thereby, low NOx can be realized. Further, since the gas show path flowing out from the gas discharge port 17 is suppressed, the discharge of unburned components such as CO and soot can be suppressed.

Although a detailed description is omitted, the same effect as that at the time of low combustion is exhibited even at the time of high combustion, and it has been confirmed that the effect at the time of high combustion is superior in the NOx reduction effect. On the other hand, regarding the effect of reducing CO and soot, it was confirmed that the low combustion was superior.

  Next, a boiler according to a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the difference from the first embodiment is that the burner 20 of the first embodiment is a self-recirculation type burner 50, and common portions are denoted by the same reference numerals and description thereof is omitted.

  The ambient air ejection part 27 of the burner 50 according to the second embodiment uses at least a part of the air ejected from each ambient air ejection part 27 (first ambient air ejection part 27a to sixth ambient air ejection part 27f). Guide portions 42 (first guide portion 42a to sixth guide portion 42f) guided in a direction away from the gas discharge port 17, and respective ambient air ejection portions 27 (first ambient air ejection portion 27a to sixth ambient air ejection portion 27f). ) Has a diffusing portion 43 (first diffusing portion 43a to sixth diffusing portion 43f) that promotes diffusion of air ejected from the air.

  In the second embodiment, as in the first embodiment, six substantially trapezoidal through-hole portions 31 (first through-hole portion 31a to sixth through-hole portion 31f) are perforated. The difference from the first embodiment is that the guide portion 42 (first guide portion 42a) is formed by using a plate-like member on the side of the gas discharge port 17 in each through hole portion 31 ("left side" in each drawing of this embodiment). To sixth guide portion 42f). This guide portion 42 is configured to cover a part of each of the through-hole portions 31, and in this embodiment, a portion not covered with the guide portion 42 is formed from the ambient air ejection portion 27. It functions as a diffusing portion 43 (first diffusing portion 43a to sixth diffusing portion 43f) that promotes diffusion of the ejected air.

  Each guide part 42 is configured to supply at least a part of air ejected from each ambient air ejection part 27 (mainly, air in a region covered by the guide part 42 of the through-hole part 31) to the gas discharge port 17. The plate-like member is inclined (inclined in the direction opposite to the gas discharge port 17 ("right side" in FIG. 7)) so as to be guided away from the gas outlet. In this case, the inclination angle θ (mounting angle) is preferably about 5 ° to 30 °.

  In addition, each guide portion 42 has a height of each guide portion 42 so that liquid fuel sprayed in a cone shape (triangular pyramid shape with the nozzle portion 22 as a vertex) from the fuel nozzle portion 22 does not contact. Is set. In the present embodiment, the fourth guide portion 43d illustrated on the right side of FIG. 7 is provided at a position where the fourth guide portion 43d is in contact with the liquid fuel more easily than the first guide portion 42a illustrated on the left side. The part 42d is provided lower than the first guide part 42a. This is because the fuel injection angle by the burner 22 is wider than that in the first embodiment.

  As described above, the diffusion portion 43 (the first diffusion portion 43a to the sixth diffusion portion 43f) is a portion of the through-hole portion 31 that is not covered by the guide portion 42 (in FIG. 7 and FIG. 8, a broken line). (Enclosed area). Since this part (diffusion part 43) is not provided with an element for rectifying the air supplied via the second air supply path 25, such as the guide part 42, it is ejected from the diffusion part 39. The air will expand rapidly.

  Therefore, in the burner 50 of the second embodiment, the air ejected from the ambient air ejecting portion 27 is guided in the direction away from the gas exhaust port 17 by the guide portion 42, and a part thereof is the diffusing portion. 43 promotes diffusion.

  Also in the boiler 1 according to the second embodiment, although not shown, basically, the central portion of the combustion chamber 16 is substantially formed in the can body 10 at the time of low combustion and high combustion of the burner 20 as in FIG. A gas F1 (solid line) spread uniformly as a center is formed. The gas F1 having such a shape is formed so that the gas generated in the burner 20 from the gas discharge port 17 is not short-passed by the shielding plate 18 and the fuel nozzle portion. The ambient air ejection part 27 provided around 22 prevents the gas generated in the burner 20 from the gas exhaust port 17 provided in the combustion chamber 16 from short-passing. This is because the flow of the air ejected from 27 can be controlled.

  Further, the ambient air ejection part 27 constituting the burner 20 according to the second embodiment has the diffusion part 43 together with the guide part 42 that exhibits the various effects described above. As described above, the diffusion portion 39 is a portion of the through hole portion 31 that is not covered with the guide portion 42 (see FIGS. 7 and 8). That is, since the diffusion part 43 is not provided with an element for rectifying air, such as the guide part 42, the air ejected from the diffusion part 43 flows into the edge part of the diffusion part 43 ( The sharp enlargement occurs at the edge portion of the through-hole portion 31. Then, in the immediate vicinity of the burner 20, a small turbulence occurs in the air, and the mixing state of the liquid fuel sprayed from the fuel nozzle portion 22 and the air can be partially made uneven. Since the burner 20 according to the second embodiment has such a diffusion portion 43, the mixing state is not simply improved, and a partly intentionally non-uniform mixing state can be formed. That is, in the second embodiment, by providing the diffusing portion 43, it is possible to form a light and dark combustion state in the vicinity of the burner 20, so that the gas temperature can be lowered and the NOx value can be reduced. it can.

  As described above, the boiler 1 according to the second embodiment is appropriately formed in the can body 10 by reducing the gas temperature by sufficiently expanding the gas F1 in the combustion chamber 16 of the can body 10. NOx can be reduced by the synergistic effect of the gas temperature decrease due to the exhaust gas circulation flow, the gas temperature decrease due to the formation of an appropriate split flame, and the gas temperature decrease due to the concentration combustion formed by the diffusion part 43. Can be planned.

  The present invention is not limited to the above-described embodiments and examples, and various modifications can be made as necessary within a range that can be adapted to the spirit of the present invention. Both are included in the technical scope of the present invention.

  For example, the burner according to the present invention is not limited to the burners 20 and 50 described in the first and second embodiments, and may be configured as shown in FIG. 9 as necessary. Here, FIG. 9 shows an explanatory view of a longitudinal section of the burner 60 according to the third embodiment of the present invention. Since the burner 60 shown in FIG. 9 basically has the same configuration as the burners 20 and 50, the same components are denoted by the same reference numerals and the description thereof will be omitted. The characteristic part of the burner 60 concerning Example 3 is mainly demonstrated.

  The difference between the burner 20 described above (see FIG. 3 and the like) and the burner 60 shown in FIG. 9 is the presence or absence of the combustion cylinder 61. That is, the burner 60 according to the other embodiment is the burner according to the first embodiment in that the combustion cylinder 61 is provided outside the second air supply path 25 constituting the ambient air ejection portion 27. 20 and its configuration is different.

  The combustion cylinder 61 is provided outside the second cylinder member 35 using a connecting means 62 such as a bolt, and a predetermined space (described later) is provided between the second cylinder member 35 and the combustion cylinder 61. The circulation part 63) is provided. In the third embodiment, the burning cylinder 61 is fixed to the outside of the second cylinder member 35 using six connection means 62 provided at equal intervals.

According to the burner 60 configured as shown in FIG. 9, the exhaust gas circulating in the can body 10 is mixed into the combustion cylinder 61 via the circulating portion 63, and NOx It is also possible to reduce the value. Further, by providing this combustion cylinder 61, it becomes possible to suppress the spread of gas and promote the combustibility in the vicinity of the burner 60. Therefore, low O ₂ (the residual oxygen concentration in the exhaust gas is about 2% to 3%). ) Side CO rise can be suppressed. However, these effects vary depending on various conditions such as the state of air ejection in the burner, the amount of combustion of the boiler, the gas shape in the can body 10, the water pipe arrangement constituting the can body 10, etc. It is necessary to determine whether or not this combustion cylinder 61 is provided.

  9 shows the case where the combustion cylinder 61 is provided vertically, but the present invention is not limited to this configuration. Therefore, for example, the combustion cylinder 61 itself may be provided to be inclined similarly to the guide portion 37.

  The combustion cylinder 61 can be similarly attached to the burner 50 of the second embodiment.

Next, a boiler according to Example 4 of the present invention will be described with reference to FIGS. 10 and 11. The fourth embodiment is different from the first embodiment in that the shielding plate 18 is not provided at the gas discharge port 17 but faces the gas discharge port 17 among the water tubes of the inner water tube group 13 (formation). The water pipes 13a1, 13a1 and the water pipes 14a1, 14a1 of the outer water pipe group 14 adjacent to the water pipes 13a1, 13a1. That is, each water pipe 13a1,
The upper part of the annular gas passage 15 between each water pipe 14a1 is closed by each shielding plate 18, and the first opening (gap) 64 below the shielding plate 18 is made to function as a gas discharge port, thereby the burner. And the gas discharge port 17 are substantially separated from each other. Further, the inner fin portion between the water tube 13a1 of the inner water tube group 13 and the adjacent water tube 13a2 is used as a shielding plate 18, and only the upper portion is shielded similarly to the shielding plate 18 in FIG. )is doing. In the fourth embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  Also in the fourth embodiment, as in the first embodiment, the gas generated in the burner 20 is gas discharged from the gas discharge port 17 provided in the combustion chamber 16 by the shielding plate 18 and the air nozzle portion 38. Therefore, it is possible to improve the combustion performance of the burner 20 and to reduce harmful substances.

In the fourth embodiment, the water pipe provided with the shielding plate 18 can be the water pipe 14a2 adjacent to the water pipe 14a1 (downstream with respect to the gas flow direction). Further, the shielding plate 18 between the water pipe 13a1 of the inner water pipe group 13 and the adjacent water pipe 13a2 can be formed as an inner fin portion 13b that does not form a lower opening.

Next, a boiler according to Embodiment 5 of the present invention will be described with reference to FIG. The fifth embodiment differs from the first embodiment in that a water pipe 13a3 having a small diameter (the same diameter or a large diameter) is provided at the relatively wide gas discharge port 17, and this water pipe 13a3 and the adjacent water pipe are provided. 13a1,
A shielding plate 18 is provided between each of 13a1 and 13a1. The shielding plate 18 is also provided between the water pipe 13a1 and the water pipe 13a2. The opening 64 as shown in FIG. 11 is formed below the shielding plate 18 as in the fourth embodiment.

  Also in the fifth embodiment, similarly to the first embodiment, reduction of harmful substances can be realized. And in this Example 5, since the horizontal width of the said shielding board 18 can be made narrow compared with the said Example 1, the deformation | transformation by a thermal stress can be decreased.

Next, a boiler according to Embodiment 6 of the present invention will be described with reference to FIGS. In the sixth embodiment, the difference from the fifth embodiment is that the outer diameter of the lower portion of the water pipes 13a3, 13a3, 13a3 provided in the relatively wide first gas discharge port 17 is reduced (smaller than the outer diameter of the upper portion). The water pipes 13a3, 13a3, and 13a3 are in contact with the adjacent water pipes so that the upper part of the gas discharge port 17 is shielded without providing the shielding plate 18. In the sixth embodiment, a first opening (gap) 64 formed in the lower part of the water pipes 13a3, 13a3, 13a3 is connected to the annular gas passage 15.

  In the sixth embodiment, the water pipes 14a3 and 14a3 located in the second gas discharge port 19 of the outer water pipe group 14 are used as water pipes with the upper part squeezed, and a second opening (gap) 65 formed by this upper throttle part. The gas from the annular gas passage 15 is discharged to the second annular gas passage 67 between the annular passage structure 66 and the outer water pipe group 14. The gas flowing through the second annular gas passage is discharged out of the can body 10 from an exhaust gas outlet 68 formed in the passage structure 66. In FIGS. 12 and 13, the upper header 11, the lower header 12, the inner water pipe group 13, and the outer water pipe group 14 are not directly related to the present invention, so that the description thereof is omitted and the same reference numerals as those in the first embodiment are used. The constituent elements marked with are substantially the same, and the description thereof is omitted.

  Also in the sixth embodiment, similarly to the fifth embodiment, the reduction of harmful substances can be realized. In the sixth embodiment, the first gas discharge port 17 is formed in the lower portion, the second gas discharge port 19 is formed in the upper portion, and the second annular gas passage 67 is formed. Compared with 5, heat efficiency can be improved. Moreover, since the said shielding board 18 is not used, it can be set as a highly durable can.

Next, a boiler according to Example 7 of the present invention will be described with reference to FIG. In the seventh embodiment, the shielding plate 18 of the first embodiment is formed in a block shape by castable. In FIG. 15, the shielding plate 18 is constituted by filling four water pipes 13a1, 13a1, 14a1, 14a1 with castable. In the seventh embodiment, the function as a shielding plate is substantially the same as that of the first embodiment, and the description thereof is omitted.

(Other variations)

  Further, in the first and second embodiments described above, the constituent walls 38a to 38f of the air nozzle portion 38 and the guide portion 42 provided in the respective ambient air ejection portions 27 have the same angles in the same direction. However, the present invention is not limited to this configuration. Therefore, for example, the installation inclination angles of the respective constituent walls 38a to 38f and the guide portion 42 may be appropriately changed.

Further, in the above-described second embodiment, the case where the guide portion 42 is configured using a plate-shaped member (scoop type) having a U-shaped cross section is described, but the present invention is not limited to this configuration, Any configuration may be used as long as at least a part of the air ejected from the ambient air ejecting portion 27 can be guided away from the gas discharge port 17. Therefore, you may comprise a guide part using the flat plate-shaped member of 1 sheet, for example. In particular,
A plate-like plate-like member may be inclined and provided on “one side” closest to the gas discharge port 17 of the through-hole portion 31 constituting each ambient air ejection portion 27. Even with such a configuration, it is possible to guide at least a part of the air ejected from the ambient air ejecting portion 27 in a direction away from the gas exhaust port 17, thereby obtaining the various effects described above. Can do.

  In the above-described embodiment, the high-flammability second nozzle 22b is disposed on the central axis of the first cylindrical member 34, and the low-flammability first nozzle 22a is placed on the gas with respect to the central axis. Although it arrange | positions spaced apart to the side away from the discharge port 17, this invention is not limited to this arrangement | positioning. For example, the center between the second nozzle 22b and the first nozzle 22a can be disposed so as to overlap the central axis of the first cylindrical member 34. 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).

  Further, in each of the above embodiments, 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, C heavy oil, etc. Applicable.

It is explanatory drawing of the longitudinal cross-section of the boiler concerning Example 1 of this invention. It is explanatory drawing of the cross section which follows the II-II line | wire of FIG. It is explanatory drawing of the longitudinal cross-section of the burner concerning the present Example 1. FIG. FIG. 4 is a bottom view of the burner shown in FIG. 3. It is the schematic which shows the flow of the gas at the time of low combustion. It is explanatory drawing of the longitudinal cross-section of the boiler concerning the other Example 2 of this invention. It is explanatory drawing of the longitudinal cross-section of the burner shown in FIG. FIG. 8 is a bottom view of the burner shown in FIG. 7. It is explanatory drawing of the longitudinal cross-section of the burner of other Example 3 of this invention. It is explanatory drawing of the cross section which follows the II-II line | wire of FIG. 1 of the other Example 4 of this invention. It is explanatory drawing which looked at the principal part of the Example 4 from the inside. It is explanatory drawing of the cross section which follows the II-II line | wire of FIG. 1 of other Example 5 of this invention. It is explanatory drawing of the cross section of the other Example 6 of this invention. It is explanatory drawing of the longitudinal cross-section of the boiler concerning the Example 6. FIG. It is explanatory drawing of the cross section of the other Example 7 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Boiler 10 ... Can body 11 ... Upper header 12 ... Lower header 13 ... Inner water pipe group 13a ... Inner water pipe 13b ... Inner fin part 14 ... Outer water pipe group 14a ... Outer water pipe 14b ... Outer fin part 15 ... Annular gas passage 16 ... Combustion chamber 17 ... Gas discharge port 18 ... Shield plate 19 ... Outer opening 20, 50, 60 ... Burner 21 ... Mounting plate 22 ... Fuel nozzle part 22a ... First fuel nozzle part 22b ... Second fuel nozzle part 23 ... Ignition Insulator 24 ... First air supply path 25 ... Second air supply path 26 ... Central air ejection part 27 ... Ambient air ejection part 27a-27f ... First ambient air ejection part-sixth ambient air ejection part 31 ... Through-hole part 31a ˜31f... First through-hole portion to sixth through-hole portion 34... First cylinder member 35... Second cylinder member 36 .. first air supply plate 37 ... second air supply plate 38. 1st air nozzle part-6th air nozzle part 39a-39f ... 1st cylinder structure wall-6th cylinder structure wall 40 ... Wind box 41 ... Partition 42 ... Guide part 42a-42f ... 1st guide part-6th guide part 43 ... Diffusion part 43a-43f ... 1st diffusion part-6th diffusion part 61 ... Combustion cylinder 62 ... Connection means 63 ... Circulation part

Claims (8)

A boiler comprising a can body configured by using a plurality of water pipes, and a burner disposed at an upper portion of the can body, wherein a gas discharge port of the combustion chamber is provided on a side surface of the combustion chamber,
The apparatus includes an outflow suppression means for suppressing the gas ejected from the burner from being short-passed from the vicinity of the burner of the gas discharge port by separating the burner and the gas discharge port. A featured boiler.   2. The boiler according to claim 1, wherein the outflow suppression unit is configured to separate the burner and the gas discharge port by closing an upper portion of the gas discharge port.   3. The upper part of the gas discharge port is closed by providing a water pipe with a reduced diameter in the lower part at the gas discharge port, and bringing the upper part of the water pipe and an adjacent water pipe into contact with each other. Boiler. The can body includes an inner water tube group in which a large number of water tubes are annularly arranged, and an outer water tube group in which a large number of water tubes are disposed outside the inner water tube group, and the inside of the inner water tube group serves as a combustion chamber. The gas outlet of the combustion chamber is provided on the side surface of the inner water tube group,
The upper part of the passage between the water pipe of the inner water pipe group facing the gas outlet and the water pipe of the outer water pipe group adjacent to the water pipe is closed, and the lower part functions as a gas outlet. The boiler according to claim 1, wherein the burner and the gas discharge port are substantially separated from each other.   The boiler according to any one of claims 1 to 4, wherein the gas discharge port is formed to be biased on a side surface of the combustion chamber.   The boiler according to claim 5, further comprising gas flow control means for controlling a gas flow formed by the burner in a direction away from the gas discharge port.   The boiler according to claim 6, wherein the gas flow control means is a plurality of air nozzles for ejecting secondary air provided around the nozzle of the burner at a tip portion of the burner.   The boiler according to any one of claims 1 to 7, wherein the burner is a self-recirculation type burner.

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