JP2013190161A - Spray nozzle, burner, and combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote ignition by gathering fine particles near a spray nozzle, and to promote mixing of sprayed particles and combustion air by raising momentum of spray.SOLUTION: Mixed fluid passages 18, 19 in which a mixed fluid of a fluid to be sprayed and a spraying medium flows are disposed opposite each other near a jetting hole 2. A spray nozzle sprays from the jetting hole 2 the mixed fluid atomized by making the mixed fluid collide. For instance, openings of passages 14, 15 of the spraying medium connected to passages 10, 11 of the fluid to be sprayed are located at both end sides in the width direction perpendicular to the flow direction of the fluid to be sprayed.

Description

  The present invention relates to a spray nozzle, a burner, and a combustion apparatus, and in particular, includes a spray nozzle that atomizes a spray fluid by supplying a spray medium such as air or steam to a spray fluid such as liquid fuel, and the spray nozzle. The present invention relates to a burner and a combustion apparatus.

  In a high-output, high-load combustion apparatus such as a power generation boiler, a floating combustion method that horizontally burns fuel is often employed. When a liquid fuel such as fuel oil is used as the fuel, the fuel is atomized by a spray nozzle and floated in the furnace of the combustion apparatus and burned. Such a spray nozzle is used in a combustion apparatus that uses liquid fuel as a main fuel, as well as in a combustion apparatus that uses solid fuel as a main fuel, such as pulverized coal, for auxiliary fuel (liquid fuel) for startup and flame stabilization. Often installed for combustion.

  As a form of spray nozzle, in general, a spray fluid (liquid fuel, etc.) is pressurized and the pressure energy is used for atomization. In addition to the spray fluid, air or steam is supplied as a spray medium for atomization. In addition, there is a two-fluid spray method that atomizes by mixing with a spray fluid. These methods are subdivided by a method of ejecting pressurized spray fluid and a method of mixing spray media. Examples of the spray nozzle using the two-fluid spray method include those described in Patent Documents 1 and 2.

  In Patent Document 1, liquid fuel and a spray medium are mixed in a Y-shaped channel and ejected. The liquid fuel is refined by mixing with the spray medium or by flowing at high speed during ejection.

  In Patent Document 2, gas is collided and mixed so as to intersect with the liquid ejected from the liquid outflow hole, and the gas-liquid mixture opposed in the vicinity of the ejection port is collided. A liquid is refined | miniaturized by colliding as collision mixing with gas or a gas-liquid mixture. By making the gas-liquid mixture, the collision force becomes stronger than in the case of the liquid alone, and the liquid is further refined. In addition, since it sprays in fan shape from an injection port, it is also called a fan spray type.

JP 2010-127518 A JP-A-9-239299

  In the combustion of liquid fuel, if the spray particle size is large, the combustion reaction is delayed, so that the combustion efficiency is reduced, soot and carbon monoxide are likely to be generated. Further, even when the spray particle size is small, mixing with the combustion air is poor, and if the combustion air around the spray particles is insufficient, soot and carbon monoxide are likely to be generated. For this reason, in the combustion of liquid fuel, it is necessary to pay attention to atomization and mixing of spray particles and combustion air.

  According to the study by the present inventors, when the liquid fuel is sprayed and burned, the particle size and momentum of the spray particles stabilize the flame (promote spray ignition) and promote mixing with combustion air. This is important for reducing unburned fuel and reducing dust by promoting mixing with combustion air.

  For example, particles that have been atomized to a diameter of less than 100 μm, preferably 50 μm or less (hereinafter referred to as “fine particles”) have a large surface area in the volume, and are easily heated by heat radiation from the furnace and burn easily. For this reason, if these fine particles are retained in the vicinity of the spray nozzle, the ignition of the spray is accelerated, contributing to stabilization of the flame and promotion of the combustion reaction.

  Further, for example, particles having a diameter of 100 μm or more and 300 μm or less (hereinafter referred to as large particles) have a relatively large particle size, and therefore have a large momentum and are not easily influenced by the gas around the spray nozzle. For this reason, the spray normally reaches a position separated by about 1 m or more, and mixing with the combustion air supplied from a position away from the spray nozzle is easy. For this reason, combustion reaction advances and generation | occurrence | production of an unburned part and soot can be suppressed.

  For this reason, according to the study by the present inventors, in order to stabilize the flame, reduce the unburned content, and suppress the dust, some of the spray particles are retained in the vicinity of the spray nozzle as fine particles. It is desirable to maintain stability and facilitate the mixing of the other spray particles with combustion air as large particles with large momentum.

  In the burner tip (spray nozzle) shown in Patent Document 1 described above, since the mixture of the liquid fuel and the spray medium is ejected at high speed from the ejection hole, the momentum of the mixture is high, and the relatively large spray particles in the spray particles. (Large particles) and atomized fine particles (fine particles) are ejected in the same direction. For this reason, the fine particles are easily accompanied by the large particles, and there are few fine particles staying in the vicinity of the spray nozzle.

  Further, in the two-fluid nozzle (spray nozzle) shown in Patent Document 2 described above, the momentum is reduced on the outer peripheral side of the fan-shaped spray, and the fine particles staying in the vicinity of the spray nozzle are larger than those in Patent Document 1. Increasing the amount of gas in the gas-liquid mixture in order to stabilize the flame by increasing the amount of fine particles staying near the spray nozzle increases the amount of fine particles on the outer periphery of the fan spray, but the central part of the fan spray As the diameter decreases, the momentum decreases, and mixing with the combustion air may deteriorate. On the other hand, if the amount of gas in the gas-liquid mixture is reduced, the momentum in the central portion of the fan spray increases, but the amount of fine particles on the outer periphery side of the fan spray decreases and the stabilization of the flame may be impaired.

  As described above, in the conventional spray nozzle, fine particles are collected in the vicinity of the spray nozzle to promote ignition (stabilize the flame), and the momentum of the spray is increased to promote mixing of the spray particles and the combustion air. It is difficult to achieve both.

  An object of the present invention is to provide a spray nozzle capable of collecting fine particles in the vicinity of the spray nozzle and promoting ignition, and increasing the momentum of spray to promote mixing of spray particles and combustion air, and the spray nozzle. It is to provide a burner and a combustion device.

  In order to achieve the above object, the spray nozzle of the present invention and the spray nozzle in the burner and combustion apparatus of the present invention collide a mixed fluid, which is a mixture of the spray fluid and the spray medium, facing each other near the ejection hole, The ratio of the spray medium in the mixed fluid before the collision in the width direction of the flow of the mixed fluid when the tip of the spray nozzle is viewed from the spray direction. The mixed fluids are made to collide with each other.

  Preferably, the ratio of the spray medium on both ends in the width direction of the mixed fluid flow is increased to cause the mixed fluid to collide.

  According to the present invention, where the ratio of the spraying medium in the mixed fluid is low and high, the mixed fluid is collided and sprayed to generate a mixed fluid having a high ratio of the spraying medium. The spray to be sprayed is atomized, and the spray generated by the mixed fluid in the portion where the ratio of the spray medium is low becomes a spray having a relatively large particle size. For this reason, while being able to increase the fine particles which contribute to flame stabilization, the spray with high momentum which reaches | attains the combustion air which flows through the position away from the spray nozzle can also be formed together. Accordingly, it is possible to collect fine particles in the vicinity of the spray nozzle and promote ignition, and to increase the momentum of spray and promote mixing of spray particles and combustion air.

  In addition, according to the present invention, since the ratio of the spray medium on both end sides is increased, the fine particles on the outer peripheral side of the spray can be effectively increased, and atomization of the spray is necessary. As a result, the amount of the spray medium used can be reduced, and the energy efficiency of the combustion apparatus can be increased.

Sectional drawing of the spray nozzle front-end | tip part which concerns on 1st Example of this invention. The top view of the spray nozzle front-end | tip part which concerns on 1st Example of this invention. Explanatory drawing which shows each flow path of the spray fluid / spraying medium / mixed fluid of the spray nozzle front-end | tip part vicinity of the spray nozzle which concerns on 1st Example of this invention. Explanatory drawing which shows the flow-path cross section of the mixed fluid flow path of the spray nozzle front-end | tip part which concerns on 1st Example of this invention. The top view of the spray nozzle front-end | tip part which concerns on the modification of the 1st Example of this invention. Explanatory drawing which shows an example of the burner of this invention. It is explanatory drawing which shows an example of the combustion apparatus of this invention. Sectional drawing of the spray nozzle front-end | tip part which concerns on the 2nd Example of this invention. Explanatory drawing which shows each flow path of the spray fluid / spraying medium / mixed fluid of the spray nozzle front-end | tip part vicinity of the spray nozzle concerning 2nd Example of this invention vicinity. Explanatory drawing which shows each flow path of the spray fluid / spraying medium / mixed fluid in the vicinity of the ejection hole at the tip of the spray nozzle according to a modification of the second embodiment of the present invention.

  The spray nozzle according to the embodiment of the present invention supplies liquid fuel as a spray fluid with pressure applied, and supplies another fluid (steam or compressed air) as a spray medium with pressure applied. The spray fluid and the spray medium In the nozzle in which the mixed fluids are caused to collide with each other near the ejection hole (internal / upstream) and ejected, in the width direction of the flow of the mixed fluid, for example, in the portion where the spray fluid and the spray medium are connected, The ratio of the spray medium in the mixed fluid before the collision is locally changed by connecting the spray fluid or the spray medium so as to be biased with respect to the flow path at the connection destination.

  By locally changing the ratio of the spray medium in the mixed fluid, the portion of the mixed fluid ejected from the ejection hole (spray nozzle outlet) having a high ratio of the spray medium is atomized. For this reason, the amount of fine particles increases and the combustion reaction proceeds, so that it is easy to stably hold the flame. On the other hand, the particle diameter is relatively large in the portion where the ratio of the spray medium is low. For this reason, the momentum of the spray is high, and it reaches the combustion air flowing at a position away from the spray nozzle, the combustion reaction proceeds, and unburned matter and dust can be suppressed.

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

  In this embodiment, the spray fluid channel is provided on the outer side with the spray hole as the center, the spray medium channel is connected to the spray fluid channel upstream of the spray hole, and The connection between the spray fluid flow path and the spray medium flow path is on both ends in the width direction with respect to the flow direction of the spray fluid.

  1-4 show the spray nozzle (tip portion) of this embodiment. FIG. 1 is a cross-sectional view of a spray nozzle tip 1 connected upstream to a supply system (not shown) of a spray fluid (liquid fuel) and a supply system (not shown) of a spray medium (such as steam or compressed air). Show. 2 is a plan view of the tip 1 of the ejection nozzle, and FIG. 3 is an explanatory view showing the state of the flow path in the vicinity of the ejection hole of the spray nozzle tip 1 shown in FIG. The illustration of the outline of the tip is omitted (the same applies to FIGS. 9 and 10). FIG. 4 is an explanatory diagram showing a cross-sectional shape of the mixed fluid flow path as viewed in the direction of arrows BB in FIG.

  As shown in FIG. 1, the spray nozzle tip 1 is composed of an outer member 1a and an inner member 1b. The atomizing fluid and the atomizing medium pass through independent channels and are mixed at the connection portion, and flow through the mixed fluid channel. That is, the spray fluid flows in the spray fluid flow paths 10 to 13 at the spray nozzle tip 1. The spray fluid channels 10 and 12 are formed between the outer member 1a and the inner member 1b, and the spray fluid channels 11 and 13 are formed in the inner member 1b. In this embodiment, the spray fluid channels 10 and 12 are formed between the outer member 1a and the inner member 1b, but may be formed in the inner member 1b in the same manner as the spray fluid channels 11 and 13. . The spray medium flows divided into spray medium flow paths 14 to 17 and is connected to the spray fluid flow paths 10 to 13 on the upstream side of the ejection holes 2 and 3, respectively. The spray medium flow paths 14 to 17 are formed in the inner member 1b. The spray medium flow path is connected with an inclination to the spray fluid flow path so that the spray fluid and the spray medium are mixed (so as not to be in parallel flow). Thus, the degree of mixing is different between the center side and the both end sides in the width direction of the spray fluid flow path. The atomizing fluid and the atomizing medium are mixed at the connecting portion, and are ejected from the ejection holes 2 and 3 through the mixed fluid flow paths 18 to 21, respectively. That is, the mixed fluid channels 18 and 19 and the mixed fluid channels 20 and 21 form opposing channels on the inside (upstream) side of the ejection holes 2 and 3, respectively. The mixed fluid flow paths 18 to 21 are formed between the outer member 1a and the inner member 1b. The mixed fluid channels 18 to 21 may be formed in the inner member 1b in the same manner as the spray fluid channels 11 and 13.

  The mixed fluid ejected from the ejection holes 2 and 3 is fan-shaped spray in a direction perpendicular to the flow direction of the mixed fluid channels 18 and 19 and the mixed fluid channels 20 and 21 (the direction in which the mixed fluid channel extends / exists). Form. The ejection nozzle tip 1 is formed with a recess 4 in the same direction as the fan-shaped spray formation, and the openings of the ejection holes 2 and 3 are formed on the bottom surface of the recess 4. The atomizing fluid is refined by mixing with the atomizing medium in the flow path, and a thin liquid film is formed by the collision force at the outlets of the ejection holes 2 and 3, and is divided by the shearing force with the surrounding gas after the ejection, Atomize. Such a spraying method for atomizing by the impact force of fluid is generally referred to as fan spray spraying.

  In the fan spray type spray, the mixed fluid collides in the ejection holes 2 and 3 and spreads in a right angle direction, so that the momentum of the spray decreases. In particular, the momentum of the spray is low in the outer peripheral portion of the spray, and the amount of fine particles (diameter less than 100 μm) increases. Due to the low momentum, the fine particles tend to stay near the spray nozzle. Particles that are atomized to a diameter of less than 100 μm, preferably 50 μm or less (hereinafter referred to as “fine particles”) have a large surface area in the volume, and are easily combusted by increasing the temperature by heat radiation from the furnace. For this reason, by making these fine particles stay in the vicinity of the spray nozzle, the ignition of the spray is accelerated, contributing to stabilization of the flame and promotion of the combustion reaction. The degree of atomization can be adjusted by the pressure of the mixed fluid and the amount of spraying medium (ratio of the spraying medium to the spraying fluid).

  In the fan spray type spray, the central portion of the spray has a larger spray amount and a higher momentum than the outer peripheral portion. Furthermore, there are many large particles (diameter 100-300 micrometers). Because of its high momentum and relatively large particle size, spraying is less susceptible to the effects of gas around the spray nozzle than fine particles. For this reason, the spray normally reaches a position separated by 1 m or more, and mixing with the combustion air supplied from a position away from the spray nozzle is easy. By mixing with combustion air, the combustion reaction proceeds and the generation of unburned matter and soot can be suppressed.

  Further, in this embodiment, a plurality of ejection holes are provided at the tip of the spray nozzle, and the flame is divided into a plurality of parts by forming sprays in different directions from the respective ejection holes. When a divided flame is formed, the surface area of the flame is increased, and the effect of radiation cooling from the flame is enhanced. For this reason, nitrogen oxide (NOx) which is easy to produce | generate at high temperature can be reduced. In addition, since the combustion air is easily mixed from around the flame by the divided flame, generation of unburned matter and soot can be reduced. In this embodiment, four ejection holes are provided as shown in FIG. 2, but two or three may be used. Five or more may be provided. By providing a large number of ejection holes, the effect of the divided flame is enhanced, and the amount of liquid fuel ejected can be increased to increase the amount of combustion. However, the present invention does not necessarily require a divided flame, and the effect of the divided flame cannot be obtained, but a single ejection hole may be used.

  To reduce the stability of the flame and the unburned matter, soot and nitrogen oxides, as described above, a part of the spray is retained as fine particles near the spray nozzle, and the other particles are used as large particles with large momentum for combustion. It is desirable to promote mixing with air. In the fan spray type, it is possible to make some of the spray stay in the vicinity of the spray nozzle as fine particles and other particles as large particles with large momentum to promote mixing with the combustion air to some extent. In order to achieve a more reliable effect of stabilizing and suppressing the generation of unburned matter and dust, the amount of fine particles staying in the vicinity of the spray nozzle is increased, the spray momentum is increased, and the spray particles and combustion air are increased. It is necessary to promote mixing with.

  In the present embodiment, as shown in FIG. 3, the connection of the spraying medium flow paths 14 and 15 to the spraying fluid flow paths 10 and 11 is performed, and the openings of the spraying medium flow paths 14 and 15 are in the flow direction of the spraying fluid. On the other hand, the fine particles staying in the vicinity of the spray nozzle are increased, and the momentum of the spray is increased to promote the mixing of the spray particles and the combustion air. In FIG. 3, the ejection holes 2 and the recesses 4 are indicated by broken lines in order to show the positional relationship with the flow path (the same applies to FIGS. 9 and 10).

  In this way, if the spray medium flow path is connected to the spray fluid flow path, the ratio of the spray medium to the mixed fluid is low in the central portion in the width direction and high on both ends. In the mixed fluid formed in a fan shape from the ejection holes 2 and 3 on the downstream side of the mixed fluid flow paths 18 to 21, the ratio of the spray medium in the central portion is low and is high in the outer peripheral portion.

  Since the ratio of the spray medium is low in the central portion of the spray, the spray has a relatively large particle size and a high momentum compared to the case where the conventional spray medium and the spray fluid are uniformly mixed. The large particles are less susceptible to the gas around the spray nozzle than the fine particles, and the spray usually reaches a position 1 m or more away and is easy to mix with the combustion air supplied from a position away from the spray nozzle. . By mixing with combustion air, the combustion reaction proceeds and the generation of unburned matter and soot can be suppressed.

  On the other hand, since the ratio of the spray medium is high in the outer peripheral portion of the spray, the spray has a relatively small particle diameter and a low momentum compared to the case where the conventional spray medium and the spray fluid are uniformly mixed. These fine particles are more easily affected by the gas around the spray nozzle than large particles, stay in the vicinity of the spray nozzle, and react quickly to contribute to flame stability.

  In this way, by changing the ratio of the spray fluid to the spray medium in the mixed fluid in the width direction in the upstream flow path of the ejection hole, a spray that promotes both the combustion reaction and contributes to the stability of the flame is formed. (In other words, two types of sprays can be formed together). Furthermore, by using the spraying medium only for the portion of the spray that needs to be atomized, the amount of fine particles in the vicinity of the spray nozzle can be increased without increasing the amount of the spraying medium used. The amount of medium used can be reduced. For this reason, the power required to increase the pressure of the spraying medium is reduced, and when steam is used as the spraying medium, the amount of steam supplied to the combustion device is reduced, and the sensible heat loss of steam in the combustion exhaust gas is reduced. The energy efficiency of the combustion device can be increased (energy loss such as a decrease in boiler efficiency can be suppressed).

  In the spray nozzle of the present embodiment, the flow channel cross sections of the mixed fluid flow channels 18 to 21 are basically rectangular or semicircular, but the flow channel cross section of the mixed fluid flow channel 18 is sprayed as shown in FIG. When the fluid flow path 10 and the spray fluid flow path 14 are separated downstream of the mixing portion, the spray holes are also changed in the width direction in the ratio of the spray fluid to the spray medium in the mixed fluid in the upstream flow path of the spray holes. It becomes easy to eject from 2. Separation in the cross section of the flow path can be performed using a partition or the like in addition to changing the flow path depth as shown in FIG.

  In the above-described embodiment, the fan spray is formed in a direction perpendicular to the radial direction of the spray nozzle tip 1, but as shown in FIG. 5, the fan spray is formed. May be formed in the same direction as the radial direction of the spray nozzle tip 1. In this case, the mixed fluid channels 18 and 19 and the mixed fluid channels 20 and 21 are formed to extend in a direction perpendicular to the radial direction of the spray nozzle tip 1.

  FIG. 6 shows an example of a burner using the above-described spray nozzle (spray nozzle tip 1), and FIG. 7 shows an example of a combustion apparatus equipped with the burner.

  As shown in FIG. 6, the burner has a spray nozzle on the central axis. The spray nozzle includes a spray nozzle tip 1 located on the central axis, a coaxial flow path component 30 through which a spray fluid and a spray medium flow, a flame stabilizing obstacle 31 provided near the spray nozzle tip 1 and The igniter 48 is used. As the obstacle 31, a swirl flow generator or a baffle plate having a slit is generally used.

  A fan-shaped spray is formed in the furnace 42 from the spray nozzle tip 1. The fan-shaped spray is divided into a central portion 33 and outer peripheral portions 34a and 34b. The central portion 33 of the spray has a larger spray amount, a higher momentum, and a larger amount of large particles (diameter 100 to 300 μm) than the outer peripheral portions 34a and 34b. Since the momentum is high and the particle size is relatively large, the spray usually reaches a position separated by 1 m or more. In the outer peripheral portions 34a and 34b of the spray, the momentum of the spray is low and there are many fine particles (diameter of 100 μm or less). Due to the low momentum, the fine particles tend to stay near the spray nozzle.

  6 and 7, in order to show the central portion 33 and the outer peripheral portions 34a and 34b of the spray for comparison, they are described as being divided, but in actuality, both change continuously.

  Combustion air is supplied from the window box 35 in three flow paths. The primary flow path 36, the secondary flow path 37, and the tertiary flow path 38 are located closer to the central spray nozzle tip 1. The primary air 39, the secondary air 40, and the tertiary air 41 are ejected into the furnace 42, respectively. The outer periphery of the tertiary flow path 38 is connected to the furnace wall 43. A heat transfer tube 44 is provided on the furnace wall 43. Further, the swirling flow generators 45 and 46 and the guide plate 47 are used to change the direction in which the combustion air is ejected to suppress the generation of soot and NOx. The flow rates of the primary flow path 36 to the tertiary flow path 38 are controlled by dampers (not shown). These have the same structure as that of the conventional burner and will not be described in detail.

  Fine particles stay in the vicinity of the tip of the igniter 48 by bringing the igniter 48 installed near the spray nozzle tip 1 close to the spray ejected from the ejection holes 2 and 3 of the spray nozzle tip 1 described above. Further, since a portion of the primary air 39 ejected from the primary flow path 36 with a slow flow rate is formed downstream of the obstacle 31, the retention of fine particles increases.

  Further, in the spray nozzle (tip portion) of the burner of this embodiment, the connection of the spray medium flow path to the spray fluid flow path is as shown in FIG. 3, and the opening of the spray medium flow path is the flow of the spray fluid. It is performed so as to be positioned at both ends in the width direction with respect to the direction.

  The combustion apparatus of the present embodiment includes a furnace (combustion furnace) for burning fuel, a liquid fuel supply system for supplying liquid fuel to the furnace, and a combustion gas supply system for supplying combustion gas containing an oxidant to the furnace. The fuel supply system and the combustion gas supply system are connected to each other to burn the fuel provided on the furnace wall of the furnace, and the flue for supplying the combustion gas generated in the furnace to the outside of the furnace.

  Specifically, as shown in FIG. 7, the combustion apparatus of the present embodiment is provided with a plurality of burners 22 for supplying fuel and combustion air to a furnace wall 43 of a furnace 42 constituting a boiler. Yes. A combustion air supply system 51, a liquid fuel supply system 52, and a spray medium supply system 53 are connected to the burner 22. In this embodiment, the combustion air supply system branches into a pipe 55 connected to the burner and a pipe 56 connected to the air supply port 54 on the downstream side. Each pipe is provided with a flow control valve (not shown). Further, the liquid fuel supply system 52 and the spray medium supply system 53 are connected to a feeder (not shown) for adjusting pressure and flow rate on the upstream side, and the spray nozzle tip 1 is installed at the downstream end.

  In the present embodiment, the combustion air is branched into a pipe 55 and a pipe 56 and is jetted into the furnace 42 from the burner 22 and the air supply port 54, respectively. By separately supplying the combustion air, the temperature of the flame formed by the burner 22 is reduced. Further, by burning in the vicinity of the burner 22 due to air shortage, a part of the nitrogen contained in the fuel is generated as a reducing agent, and a reaction occurs in which NOx generated by the combustion is reduced to nitrogen. For this reason, the NOx concentration at the furnace outlet is reduced as compared with the case where all the combustion air is supplied from the burner 22. Further, the remaining combustion air is supplied from the air supply port 54 to completely burn the fuel, thereby reducing the unburned amount. The combustion gas 57 mixed with the combustion air from the air supply port 54 is recovered by the heat exchanger 58 at the upper part of the furnace, passes through the flue 59, and is discharged from the chimney 60 to the atmosphere.

  In the spray nozzle (tip portion) in the burner and the combustion apparatus of the present embodiment, since the ratio of the spray medium is low in the central portion 33 of the spray, compared to the case where the conventional spray medium and the spray fluid are uniformly mixed, The particle size becomes relatively large. These large particles are less susceptible to the gas around the spray nozzle than the fine particles. Therefore, the central portion 33 of the spray is easily mixed with the flow of the secondary air 40 and the tertiary air 41 flowing on the outer peripheral side of the burner. By mixing with combustion air, the combustion reaction proceeds and the generation of unburned matter and soot can be suppressed.

  On the other hand, since the ratio of the spray medium is high in the outer peripheral portions 34a and 34b of the spray, the particle diameter is relatively small as compared with the case where the conventional spray medium and the spray fluid are uniformly mixed. The fine particles are more easily affected by the gas around the spray nozzle than the large particles, and remain in the vicinity of the spray nozzle. An igniter 48 is installed near the spray nozzle tip 1, and fine particles stay near the tip of the igniter 48. Further, since a portion of the primary air 39 ejected from the primary flow path 36 with a low flow velocity is formed downstream of the obstacle 31, the retention of fine particles increases. By retaining the fine particles, the fine particles can be evaporated and burned with an electric spark with less energy than the large particles. Further, increasing the retention of fine particles makes it easier for the flame to spread. For this reason, in the burner and combustion apparatus of a present Example, it becomes easy to reliably ignite with a small capacity igniter.

  Moreover, although the case where liquid fuel was used was shown in the combustion apparatus of a present Example, it is applicable also when using solid fuel, such as pulverized coal, as main fuel, and using liquid fuel as auxiliary fuel. In this case, the above-described effect can be obtained when the liquid fuel is sprayed into the furnace 42 from the spray nozzle tip 1.

  In the example of the combustion apparatus shown in FIG. 7, an example in which the combustion air is branched into the pipes 55 and 56 is shown, but the spray nozzle of the present invention can also be applied when supplying combustion air only from the burner 22. it can.

  Further, in the example of the combustion apparatus shown in FIG. 7, the burner 22 is provided up and down on one wall surface of the furnace. A spray nozzle can be applied.

  In this example, the spraying medium flow path is provided on the outer side with the spray hole as the center, and the spraying fluid flow path is connected in the middle of the flow path toward the spray hole. And the obstruction (guide member) which guides the flow of the spraying medium to the both ends of the width direction of the flow path is provided in the spraying medium flow path upstream of the connecting portion.

  8 and 9 show the spray nozzle tip 1 according to the present embodiment. FIG. 8 shows a spray nozzle tip 1 which is connected to a supply system (not shown) for liquid fuel (atomization fluid) and a supply system (not shown) for a spray medium on the upstream side. FIG. 9 is an explanatory diagram showing the state of the flow path in the vicinity of the ejection hole when the spray nozzle tip 1 shown in FIG.

  The difference between the present embodiment and the first embodiment is the flow path structure on the upstream side of the ejection holes 2 and 3. For this reason, it demonstrates centering on the part regarding a flow-path structure.

  In the spray nozzle tip 1 of the present embodiment, the spray fluid channels 10 to 13 are connected to the spray medium channels 14 to 17 on the upstream side of the ejection holes 2 and 3, respectively. That is, as shown in FIG. 8, the spray medium flow paths 14 to 17 are disposed on the side far from the ejection holes 2 and 3, and the spray fluid flow paths 10 to 13 are disposed on the inner side (side closer to the ejection holes 2 and 3). Is arranged. The atomizing fluid channel is connected to the atomizing medium channel with an inclination. The atomizing fluid and the atomizing medium are mixed at the connecting portion, and are ejected from the ejection holes 2 and 3 through the mixed fluid flow paths 18 to 21, respectively. The mixed fluid ejected from the ejection holes 2 and 3 collides, and forms a fan-shaped spray in a direction perpendicular to the flow direction of the mixed fluid channels 18 and 19 and the mixed fluid channels 20 and 21.

  Further, as shown in FIGS. 8 and 9, an obstacle 61 for the flow of the spraying medium is provided on the upstream side of the connection portion of the spraying fluid flow paths 10 to 13 to the spraying medium flow paths 14 to 17. The obstacle 61 has a narrow width on the upstream side so that the spray medium can flow smoothly.

  The spray medium flows separately at both ends by the obstacle 61 at the connection portion. On the other hand, the atomized fluid is likely to flow through the central portion due to the obstacle 61 on the downstream side of the connecting portion. For this reason, the ratio of the spraying medium to the mixed fluid is low in the central portion in the width direction and is high at both ends as in the case of the first embodiment. The spray formed in a fan shape from the ejection holes 2 and 3 on the downstream side of the mixed fluid flow paths 18 to 21 has a low ratio of the spray medium in the central portion and is high in the outer peripheral portion. Therefore, also in the present embodiment, the same effect as that of the first embodiment can be obtained.

  In the flow channel structure shown in FIG. 9, the width of the connection opening of the spray fluid flow channels 10 and 11 to the spray medium flow channels 14 and 15 is the same as the flow channel width of the spray medium flow channels 14 and 15. However, the spray medium flow path and the spray fluid flow path may be connected only to the central portion in the width direction with respect to the flow direction of the spray medium. That is, as in the flow path structure shown in FIG. 10, the width of the spray fluid flow paths 10 and 11 is set to the same level as the downstream side of the obstacle 61, and the width direction of the spray medium flow paths 14 and 15 is You may make it provide the connection opening part of the spray fluid flow paths 10 and 11 in the center part. In this case, the ratio of the spray medium to the mixed fluid is lower in the central portion in the width direction and higher in both ends than in the flow channel structure shown in FIG. Although the effect is smaller than that of the flow path structure shown in FIG. 10, the ratio of the spraying medium to the mixed fluid in the flow path structure shown in FIG. A part can be made low and both ends can be made high.

  Also in this embodiment, the modification of the first embodiment can be applied in the same manner, and the above-described burner and combustion apparatus can be configured using the spray nozzle of this embodiment.

1: Spray nozzle tip
1a: Outer member
1b: Inside member
2, 3: Ejection hole
4: Recess
10-13: Spray fluid flow path
14-17: Spray medium flow path
18-21: Mixed fluid flow path
22: Burner
30: Coaxial flow path component
31: Obstacle
33: Central part of spray
34a, 34b: Outer periphery of spray
35: Windbox
36: Primary flow path
37: Secondary flow path
38: Tertiary flow path
39: Flow of primary air
40: Flow of secondary air
41: Flow of tertiary air
42: Furnace
43: Furnace wall
44: Heat transfer tube
45, 46: Swirl generator
47: Guide plate
48: Igniter
51: Combustion air supply system
52: Liquid fuel supply system
53: Spraying medium supply system
54: Air supply port
55, 56: Piping
57: Flow of combustion gas
58: Heat exchanger
59: Flue
60: Chimney
61: Obstacle

Claims (11)

A spray nozzle having a spray nozzle tip provided with an ejection hole for spraying a mixed fluid obtained by mixing a spray fluid and a spray medium,
The spray nozzle tip has a plurality of mixed fluid flow paths arranged to face each other so that the mixed fluid collides inside the ejection hole,
In the width direction of the flow of the mixed fluid when the tip of the spray nozzle is viewed from the spray direction, the ratio of the spray medium in the mixed fluid before the collision is made different to cause the mixed fluid to collide. A spray nozzle characterized by that. In claim 1,
The ratio of the spray medium in the mixed fluid before the collision is increased at both ends in the width direction of the flow of the mixed fluid. A spray nozzle having a spray nozzle tip provided with an ejection hole for spraying a mixed fluid obtained by mixing a spray fluid and a spray medium,
The spray nozzle tip is
A plurality of spray fluid flow paths through which the spray fluid flows;
A plurality of spray medium flow paths through which the spray medium flows;
A plurality of mixed fluid channels formed downstream of a connection portion between the spray fluid channel and the spray medium channel, the plurality of fluid channels being arranged to face each other so that the mixed fluid collides inside the ejection hole. And a mixed fluid flow path,
Connection of the spray medium flow path or the spray fluid flow path to the spray fluid flow path or the spray medium flow path is biased and connected to the spray fluid flow path or the spray medium flow path to be connected. A spray nozzle characterized by that. In claim 3,
The spray nozzle, wherein the spray medium flow path is connected to the spray fluid flow path with an inclination, and is connected to both ends in the width direction of the flow of the spray fluid flow path. In claim 3,
The spray nozzle, wherein the spray fluid flow path is connected to the spray medium flow path with an inclination, and is connected to a central side in the width direction of the flow of the spray medium flow path. In claim 5,
The spray nozzle, wherein the spray medium flow path is provided with an obstacle to the flow at a center side in a flow width direction and upstream of a connection portion of the spray fluid flow path. In claim 3,
The spray fluid flow path is connected to the spray medium flow path with an inclination, and the spray medium flow path flows at a center side in a flow width direction and upstream of a connection portion of the spray fluid flow path. A spray nozzle, characterized in that an obstacle is provided for. In any one of Claims 1-7,
The mixed fluid flow path is provided with a partition for dividing the flow path in the flow direction or a step where the flow path depth is changed. A burner that uses liquid fuel as fuel,
9. The spray nozzle according to claim 1, wherein the liquid fuel is supplied as the spray fluid to the spray nozzle tip, and steam or compressed air is supplied as the spray medium to the spray nozzle tip. A burner characterized by A combustion device for burning fossil fuel,
A combustion furnace for burning fossil fuel, a fuel supply system for supplying fossil fuel to the combustion furnace, a combustion gas supply system for supplying combustion gas to the combustion furnace, the fuel supply system, and the combustion gas supply A burner that is connected to the system and burns fossil fuel provided on the furnace wall of the combustion furnace, a heat exchanger that recovers heat from the combustion exhaust gas generated in the combustion furnace, and the combustion exhaust gas that is recovered from the heat A flue that supplies to the outside of the
The combustion apparatus using the burner of Claim 9 which used the liquid fuel as a fossil fuel as the said burner. A combustion device for burning fossil fuel,
A combustion furnace for burning fossil fuel, a fuel supply system for supplying fossil fuel to the combustion furnace, a combustion gas supply system for supplying combustion gas to the combustion furnace, the fuel supply system, and the combustion gas supply A plurality of burners that are connected to the system and burn fossil fuel provided on the furnace wall of the combustion furnace, a heat exchanger that recovers heat from the combustion exhaust gas generated in the combustion furnace, and the heat recovery combustion exhaust gas that A flue for supplying to the outside of the combustion furnace,
The burner according to claim 9, wherein one of the burners is a burner using pulverized coal as a main fossil fuel, and the other one of the burners is a liquid fuel as an auxiliary fossil fuel. Combustion device.

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