JP2017145976A - Boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate combustion of fuel in a furnace to suppress occurrence of unburned matter, in a boiler.SOLUTION: A boiler includes: a furnace 11 formed into a hollow shape and installed along a vertical direction; combustion burners 21, 22, 23 configured to jet into the furnace 11 pulverized coal mixture obtained by mixing solid fuel and combustion air; a furnace bottom air nozzle 30 configured to jet into the furnace 11 combustion air below the combustion burners 21, 22, 23 in the vertical direction; and a horizontal direction adjustment device (air jetting direction adjustment device) 51 capable of adjusting a jetting direction of combustion air from the furnace bottom air nozzle 30 to a horizontal direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a boiler for generating steam by burning solid fuel and air.

  A conventional boiler has a furnace that is hollow and is installed in a vertical direction, and a plurality of combustion burners are arranged on the furnace wall in the circumferential direction and the vertical direction. In this furnace, a flue is connected to the upper part, and a heat exchanger for collecting the heat of the exhaust gas to generate steam is disposed in the flue.

  As such a boiler, there exists a thing described in the following patent document, for example. The pulverized coal burner described in the patent document includes a nozzle body and a secondary air adjustment device, and an auxiliary air adjustment mechanism and a main air adjustment mechanism as a secondary air adjustment device. Auxiliary air volume adjustment blades that can be rotated are provided at the inlet.

Japanese Patent No. 4983416

  In general, a boiler forms a flame by injecting pulverized coal mixture and combustion air from a plurality of combustion burners into a furnace and igniting the pulverized coal mixture, and combustion gas (exhaust gas) generated in the furnace ) Will rise. By the way, the operating condition of the boiler is constantly changing, and the combustion state inside the furnace is always changing. At this time, for example, if the supply amount of combustion air injected into the furnace together with the pulverized coal mixture decreases, the combustion air does not reach the center of the furnace, and combustion at the center of the furnace becomes insufficient. Then, there is a problem that the unburned amount of fuel in the center of the furnace increases and the combustion efficiency is lowered.

  This invention solves the subject mentioned above, and aims at providing the boiler which accelerates | stimulates the combustion of the fuel in a furnace and can suppress generation | occurrence | production of an unburned part.

  In order to achieve the above object, a boiler according to the present invention is a combustion in which a furnace having a hollow shape and installed in a vertical direction, and a fuel gas mixed with solid fuel and combustion air are injected into the furnace. A burner, a furnace bottom air nozzle for injecting combustion air into the furnace below the combustion burner in a vertical direction, and a jet direction of combustion air by the furnace bottom air nozzle can be adjusted in a horizontal direction or a vertical direction. An air ejection direction adjusting device.

  Therefore, the fuel gas mixed with the solid fuel and the combustion air is ejected from the combustion burner into the furnace, and the combustion air is ejected from the furnace bottom air nozzle below the fuel gas ejection position in the furnace. At this time, if the operating condition of the boiler changes, the direction of fuel gas ejection by the combustion burner and the amount of combustion air ejected from the furnace bottom air nozzle may vary. At this time, the air ejection direction adjusting device adjusts the ejection direction of the combustion air by the furnace bottom air nozzle in the horizontal direction or the vertical direction. Therefore, the furnace bottom air nozzle can appropriately supply combustion air necessary for combustion below the fuel gas ejection position in the furnace. As a result, the combustion of fuel in the furnace can be promoted and the generation of unburned content can be suppressed.

  In the boiler according to the present invention, the combustion burner has an angle adjustment mechanism capable of adjusting a fuel gas injection direction in a vertical direction, and the fuel gas injection direction from the combustion burner is adjusted downward by the angle adjustment mechanism. In this case, the air ejection direction adjusting device changes the ejection direction of the combustion air by the furnace bottom air nozzle to the center side of the furnace or the lower side of the furnace.

  Therefore, when the fuel gas ejection direction from the combustion burner is adjusted downward by the angle adjustment mechanism, the combustion air ejected downward from the fuel gas ejection position from the furnace bottom air nozzle reaches the center of the furnace. It becomes difficult. At this time, the jet direction of the combustion air by the furnace bottom air nozzle is changed to the center side of the furnace or the lower side of the furnace by the air jet direction adjusting device. Then, the combustion air from the furnace bottom air nozzle can easily reach the center of the furnace below the fuel gas ejection position, and the fuel can be efficiently burned in the furnace.

  In the boiler according to the present invention, when the amount of combustion air ejected from the furnace bottom air nozzle decreases, the air ejection direction adjusting device sets the direction of combustion air ejected by the furnace bottom air nozzle to the center side of the furnace. Or it changes to the lower side of the said furnace.

  Accordingly, when the amount of combustion air ejected from the furnace bottom air nozzle decreases, the combustion air from the furnace bottom air nozzle that is ejected downward from the fuel gas ejection position hardly reaches the center of the furnace. At this time, the jet direction of the combustion air by the furnace bottom air nozzle is changed to the center side of the furnace or the lower side of the furnace by the air jet direction adjusting device. Then, the combustion air from the furnace bottom air nozzle can easily reach the center of the furnace below the fuel gas ejection position, and the fuel can be efficiently burned in the furnace.

  In the boiler according to the present invention, the air ejection direction adjusting device includes a horizontal direction adjusting device capable of adjusting a combustion air ejection direction by the furnace bottom air nozzle in a horizontal direction separately from a fuel gas ejection direction by the combustion burner. It is characterized by having.

  Therefore, the horizontal direction adjusting device adjusts the direction in which the combustion air is ejected by the furnace bottom air nozzle in the horizontal direction separately from the direction in which the fuel gas is ejected by the combustion burner. The air injection direction can be adjusted horizontally, and even if the combustion state of the furnace fluctuates, the combustion air from the furnace bottom air nozzle is placed below the fuel gas injection position and in the center of the furnace. Can be reached.

  In the boiler according to the present invention, the air ejection direction adjusting device includes a vertical direction adjusting device capable of adjusting a combustion air ejection direction by the furnace bottom air nozzle in a vertical direction separately from a fuel gas ejection direction by the combustion burner. It is characterized by having.

  Accordingly, the vertical direction adjusting device adjusts the direction in which the combustion air is ejected by the furnace bottom air nozzle in the vertical direction separately from the direction in which the fuel gas is ejected by the combustion burner. The air ejection direction can be adjusted to the vertical direction, and even if the combustion state of the furnace fluctuates, the combustion air from the furnace bottom air nozzle is placed below the fuel gas ejection position and in the center of the furnace. Can be reached.

  In the boiler according to the present invention, a first unburned amount measuring device for measuring the unburned amount of the solid fuel dropped on the bottom portion of the furnace is provided, and the air ejection is performed according to a measurement result of the first unburned amount measuring device. It is characterized by operating a direction adjusting device.

  Accordingly, the air jet direction adjusting device adjusts the jet direction of the combustion air from the furnace bottom air nozzle according to the amount of unburned solid fuel that has fallen to the bottom of the furnace, and the combustion air from the furnace bottom air nozzle Can reach the center of the furnace below the fuel gas ejection position, and the generation of unburned fuel can be suppressed.

  In the boiler according to the present invention, a second unburned amount measuring device for measuring an unburned amount of the exhaust gas flowing from the furnace to the flue is provided, and the air ejection direction according to the measurement result of the second unburned amount measuring device. It is characterized by operating the adjusting device.

  Therefore, the air jet direction adjusting device adjusts the jet direction of the combustion air from the furnace bottom air nozzle according to the unburned amount of the exhaust gas flowing in the flue, and the combustion air from the furnace bottom air nozzle is used as the fuel gas. It is possible to reach the center of the furnace at a position lower than the jetting position, and to suppress generation of unburned fuel.

  In the boiler according to the present invention, when the unburned fuel amount increases, the control device changes the jet direction of the combustion air by the furnace bottom air nozzle by the air jet direction adjusting device to the center side of the furnace or the lower side of the furnace. It is characterized by changing to.

  Therefore, if the amount of unburned fuel in the furnace bottom or flue increases, the direction of jetting of combustion air from the furnace bottom air nozzle is changed to the center side of the furnace or the lower side of the furnace, thereby reducing the amount of unburned fuel. Can be suppressed.

  According to the boiler of the present invention, the air ejection direction adjusting device is provided that can adjust the ejection direction of the combustion air by the furnace bottom air nozzle in the horizontal direction or the vertical direction. Generation of fuel can be suppressed.

Drawing 1 is a schematic structure figure showing the boiler of a 1st embodiment. FIG. 2 is a plan view showing the arrangement configuration of the combustion burners. FIG. 3 is a plan view showing the arrangement configuration of the furnace bottom air nozzle. FIG. 4 is a plan view illustrating a first modified embodiment of the arrangement configuration of the combustion burners. FIG. 5 is a plan view showing the arrangement configuration of the furnace bottom air nozzle of the first modified embodiment. FIG. 6 is a plan view illustrating a second modified embodiment of the arrangement configuration of the combustion burners. FIG. 7 is a plan view illustrating the arrangement configuration of the furnace bottom air nozzle according to the second modified embodiment. FIG. 8 is a schematic configuration diagram illustrating a boiler according to the second embodiment. FIG. 9 is a schematic configuration diagram illustrating a boiler according to the third embodiment.

  Hereinafter, preferred embodiments of a boiler according to the present invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment, and when there are two or more embodiments, what comprises combining each embodiment is also included.

[First Embodiment]
FIG. 1 is a schematic configuration diagram showing a boiler according to the first embodiment, FIG. 2 is a plan view showing an arrangement configuration of combustion burners, and FIG. 3 is a plan view showing an arrangement configuration of furnace bottom air nozzles.

  The boiler according to the first embodiment uses pulverized coal obtained by pulverizing coal or pulverized biomass obtained by pulverizing biomass as a pulverized fuel (solid fuel), burns the pulverized fuel with a combustion burner, and recovers heat generated by the combustion. It is a possible boiler.

  In the first embodiment, as shown in FIG. 1, the boiler 10 includes a furnace 11, a combustion device 12, and a flue 13. The furnace 11 has a rectangular hollow shape and is installed along the vertical direction. The furnace wall constituting the furnace 11 is constituted by a heat transfer tube.

  The combustion device 12 is provided in a lower part of a furnace wall (heat transfer tube) constituting the furnace 11. This combustion apparatus 12 has a plurality of combustion burners 21, 22, 23 mounted on the furnace wall. In the present embodiment, four combustion burners 21, 22, and 23 are arranged at equal intervals along the circumferential direction as one set, and three sets along the vertical direction, that is, three stages are arranged. ing. However, the shape of the furnace, the number of combustion burners in one stage, and the number of stages are not limited to this embodiment.

  Each of the combustion burners 21, 22, 23 is connected to a pulverizer (pulverized coal machine / mill) 27, 28, 29 via pulverized coal supply pipes 24, 25, 26. Further, the furnace 11 is provided below the mounting position of the combustion burners 21, 22, and 23 and is provided with a furnace bottom air nozzle 30. The furnace 11 is provided with a wind box 31 at a position where the combustion burners 21, 22, and 23 and the furnace bottom air nozzle 30 are mounted, and one end of an air duct 32 is connected to the wind box 31. A blower 33 is connected to the other end of the duct 32. Further, the furnace 11 is provided with an additional air nozzle 34 located above the mounting position of the combustion burners 21, 22, and 23, and an additional air duct 35 branched from the additional air duct 34 is connected thereto.

  The flue 13 is connected to the upper part of the furnace 11. The flue 13 has superheaters (superheaters) 41, 42, 43 as heat exchangers for recovering the heat of combustion gas, reheaters (reheaters) 44, 45, economizers 46, economizers, 47 is provided, and heat exchange is performed between the combustion gas generated by the combustion in the furnace 11 and water. Further, the flue 13 is connected to a gas duct 48 through which the combustion gas that has exchanged heat is discharged downstream. This gas duct 48 is provided with an air heater 49 between the air duct 32 and performs heat exchange between the air flowing through the air duct 32 and the exhaust gas flowing through the gas duct 48, and the combustion burners 21, 22, 23, the bottom of the furnace The temperature of the combustion air supplied to the air nozzle 30 and the additional air nozzle 34 can be raised.

  Here, although the combustion apparatus 12 is demonstrated in detail, since the combustion burners 21, 22, and 23 which comprise this combustion apparatus 12 have comprised the substantially the same structure, respectively, the combustion burner 21 is demonstrated as a representative. .

  As shown in FIG. 2, the combustion burner 21 includes combustion burners 21a, 21b, 21c, and 21d provided at four corners of the furnace 11, respectively. Each combustion burner 21a, 21b, 21c, 21d is connected to each branch pipe 24a, 24b, 24c, 24d branched from the pulverized coal supply pipe 24, and each branch pipe 32a, 32b, 32c branched from the air duct 32. , 32d (wind box 31) are connected.

  Therefore, each combustion burner 21a, 21b, 21c, 21d blows a pulverized coal mixture (fuel gas), which is a mixture of pulverized coal and carrier air, into the furnace 11, and outside the periphery of the pulverized coal mixture. Combustion air (fuel gas combustion air / secondary air) is blown in. And by igniting this pulverized coal mixture, four flames F1, F2, F3, and F4 can be formed, and these flames F1, F2, F3, and F4 are viewed from vertically above the furnace 11 ( In FIG. 2), the flame swirl flow C <b> 1 swirling counterclockwise as the center O of the furnace 11.

  Moreover, the furnace bottom air nozzle 30 is comprised from the furnace bottom air nozzles 30a, 30b, 30c, and 30d provided in the four corners in the furnace 11, respectively, as shown in FIG. Each furnace bottom air nozzle 30a, 30b, 30c, 30d is connected to each branch pipe 32a, 32b, 32c, 32d (wind box 31) branched from the air duct 32. Therefore, each furnace bottom air nozzle 30a, 30b, 30c, 30d blows combustion air into the furnace 11 below the pulverized coal mixture ejected by each combustion burner 21a, 21b, 21c, 21d. As a result, the air swirl flow C11 swirling counterclockwise as the center O of the furnace 11 is obtained as viewed from above the furnace 11 (in FIG. 3).

  In the present embodiment, as shown in FIG. 1, horizontal adjustment as an air injection direction adjusting device capable of adjusting the injection direction of combustion air by the furnace bottom air nozzle 30 (30a, 30b, 30c, 30d) in the horizontal direction. A device 51 is provided. In this case, the horizontal direction adjusting device 51 can move and adjust the furnace bottom air nozzle 30 in the horizontal direction independently of the combustion burners 21, 22, and 23.

  As shown in FIG. 2, the combustion burner 21 includes four combustion burners 21 a, 21 b, 21 c, and 21 d provided at each corner of the furnace 11. Each combustion burner 21a, 21b, 21c, 21d can form a flame swirl flow C1 by blowing pulverized coal mixture and combustion air into the furnace 11. On the other hand, as shown in FIG. 3, the furnace bottom air nozzle 30 is composed of four furnace bottom air nozzles 30 a, 30 b, 30 c and 30 d provided at each corner of the furnace 11. Each of the furnace bottom air nozzles 30 a, 30 b, 30 c, and 30 d can form an air swirl flow C <b> 11 by blowing combustion air into the furnace 11.

  In this case, as shown in FIGS. 2 and 3, the combustion burners 21 a, 21 b, 21 c, 21 d and the furnace bottom air nozzles 30 a, 30 b, 30 c, 30 d are arranged at the same position in the horizontal direction of the furnace 11. On the other hand, they are shifted in the vertical direction. And since each combustion burner 21a, 21b, 21c, 21d and each furnace bottom air nozzle 30a, 30b, 30c, 30d have the same ejection direction with respect to the furnace 11, the flame swirl flow C1 and the air swirl flow C11 are It has the same diameter.

  In the rated operation of the boiler 10, as described above, each combustion burner 21a, 21b, 21c, 21d blows pulverized coal mixture and combustion air, and each furnace bottom air nozzle 30a, 30b, 30c, 30d burns. By blowing the working air, an air swirl flow C11 having the same diameter is formed below the flame swirl flow C1. However, the operating condition of the boiler 10 changes as necessary, and the combustion state in the furnace 11 also changes.

  As shown in FIG. 1, the combustion burners 21, 22, and 23 and the furnace bottom air nozzle 30 are supported by a wind box 31, and the pulverized coal mixture and the combustion air are ejected vertically by an angle adjustment mechanism (not shown). It is adjustable. That is, the combustion burners 21, 22, 23 and the furnace bottom air nozzle 30 are supported by the wind box 31 by a support shaft extending in the horizontal direction, and the direction thereof can be changed in the vertical direction by the air cylinder. The inclination angles of the combustion burners 21, 22, 23 and the furnace bottom air nozzle 30 during the rated operation of the boiler 10 are set. For example, if the exhaust gas temperature above the furnace 11 is too high, the combustion burner 21 is adjusted by the angle adjustment mechanism. , 22 and 23 are changed so that the ejection direction is downward. Further, when the harmful substance (Nox) in the exhaust gas increases, the amount of combustion air ejected from the furnace bottom air nozzle 30 is decreased.

  When the ejection direction of the combustion burners 21, 22, 23 is downward or the amount of combustion air ejected from the furnace bottom air nozzle 30 is reduced, the jet of combustion air from each furnace bottom air nozzle 30 has an effect. Receive. That is, when the ejection direction of the combustion burners 21, 22, 23 is downward, the flame swirl flow C <b> 1 in the ejection area of the combustion air from the furnace bottom air nozzle 30 becomes stronger, and the combustion ejected from the furnace bottom air nozzle 30. There is a risk that the working air will not reach the center of the furnace 11. Further, when the amount of combustion air ejected from the furnace bottom air nozzle 30 decreases, the flow velocity of the combustion air decreases, and the combustion air ejected from the furnace bottom air nozzle 30 does not reach the center of the furnace 11. There is a fear. Then, the furnace 11 becomes deficient in oxygen at the lower center portion, and the unburned portion in the ash remaining at the bottom of the furnace rises without burning and flows into the flue 13.

  Therefore, in the present embodiment, as shown in FIG. 1, the air is discharged from the furnace bottom air nozzle 30 in the lower central region of the pulverized coal mixture and the combustion air ejected from the combustion burners 21, 22, and 23. When the arrival amount of the combustion air to be reduced decreases, the horizontal direction adjusting device 51 changes the ejection direction of the combustion air from the furnace bottom air nozzle 30 to the center O side of the furnace 11.

  As shown in FIG. 3, the four furnace bottom air nozzles 30a, 30b, 30c, and 30d provided at the respective corners in the furnace 11 are provided with horizontal adjustment devices 51a, 51b, 51c, and 51d, respectively. Each horizontal direction adjusting device 51a, 51b, 51c, 51d can change the injection direction of the combustion air by the furnace bottom air nozzles 30a, 30b, 30c, 30d to the horizontal direction. For example, when the direction of jetting combustion air from the furnace bottom air nozzles 30a, 30b, 30c, 30d is changed to the center O side of the furnace 11, it is for combustion having a smaller diameter than the air swirl flow C11 formed during rated operation of the boiler 10. An air swirl flow C12 of air can be formed.

  The horizontal adjustment device 51 (51a, 51b, 51c, 51d) can adjust the furnace bottom air nozzle 30 (30a, 30b, 30c, 30d) in the horizontal direction, but the furnace bottom air nozzle 30 (30a, 30b, The adjustment angle θ1 in the horizontal direction of 30c, 30d) is 0 degrees to 30 degrees, and preferably 5 degrees to 20 degrees.

  In the above description, the combustion burners 21a, 21b, 21c, and 21d are arranged at the four corners of the furnace 11, but the present invention is not limited to this configuration. FIG. 4 is a plan view showing a first modified embodiment of the arrangement configuration of the combustion burner, and FIG. 5 is a plan view showing the arrangement configuration of the furnace bottom air nozzle of the first modified embodiment.

  In the first modified embodiment, as shown in FIG. 4, the combustion burner 21 is composed of combustion burners 21 a, 21 b, 21 c, and 21 d provided on the furnace wall close to each corner in the furnace 11. Each combustion burner 21 a, 21 b, 21 c, 21 d blows pulverized coal mixture and combustion air into the furnace 11. Then, a flame swirl flow C1 swirling in the counterclockwise direction can be formed as the center O of the furnace 11 as viewed from above the furnace 11 (in FIG. 4).

  Moreover, as shown in FIG. 5, the furnace bottom air nozzle 30 is comprised from the furnace bottom air nozzles 30a, 30b, 30c, and 30d provided in the furnace wall close | similar to each corner part in the furnace 11, respectively. Each furnace bottom air nozzle 30a, 30b, 30c, 30d blows combustion air in the furnace 11 below the pulverized coal mixture from each combustion burner 21a, 21b, 21c, 21d. As a result, an air swirl flow C11 swirling counterclockwise as the center O of the furnace 11 can be formed as viewed from above the furnace 11 (in FIG. 5). And each furnace bottom air nozzle 30a, 30b, 30c, 30d is provided with the horizontal direction adjustment apparatus 51a, 51b, 51c, 51d, respectively, and can change the injection direction of combustion air to a horizontal direction.

  FIG. 6 is a plan view showing a second modified embodiment of the arrangement configuration of the combustion burner, and FIG. 7 is a plan view showing the arrangement configuration of the furnace bottom air nozzle of the second modified embodiment.

  In the second modified embodiment, as shown in FIG. 6, the combustion burner 21 is composed of combustion burners 21 a, 21 b, 21 c, 21 d, 21 e, and 21 f provided on opposing furnace walls in the furnace 11. Each combustion burner 21a, 21b, 21c and each combustion burner 21d, 21e, 21f face the inside of the furnace 11 and blow in the pulverized coal mixture and the combustion air.

  Further, as shown in FIG. 7, the furnace bottom air nozzle 30 includes furnace bottom air nozzles 30 a, 30 b, 30 c, 30 d, 30 e, and 30 f provided on opposing furnace walls in the furnace 11. The furnace bottom air nozzles 30a, 30b, 30c and the furnace bottom air nozzles 30d, 30e, 30f are located in the furnace 11 below the pulverized coal mixture from the combustion burners 21a, 21b, 21c, 21d, 21e, 21f. Combustion air is blown in opposition. Each of the furnace bottom air nozzles 30a, 30c, 30d, and 30f is provided with a horizontal direction adjusting device 51a, 51c, 51d, and 51f, respectively, and the ejection direction of the combustion air is set to a predetermined angle (adjustment angle θ11). ) Can be changed to a predetermined angle.

  In the boiler 10 of the first embodiment configured as described above, as shown in FIGS. 1 to 3, when the crushers 27, 28, and 29 are driven, the supplied coal is pulverized and the generated pulverized coal is The air is supplied to the combustion burners 21, 22 and 23 through the pulverized coal supply pipes 24, 25 and 26 by the conveying air. The combustion air heated by the air heater 49 is supplied to the wind box 31 by the air duct 32 and is supplied to the additional air nozzle 34 by the additional air duct 35.

  Then, the combustion burners 21, 22, and 23 blow a pulverized coal mixture in which pulverized coal and carrier air are mixed and combustion air into the furnace 11 and ignite at this time to form a flame swirl flow. The furnace bottom air nozzle 30 blows combustion air downward from the flame swirl flow in the furnace 11. Further, the additional air nozzle 34 blows additional air above the flame swirl flow in the furnace 11. In the furnace 11, the pulverized coal mixture and the combustion air are combusted to generate a flame swirl, and the combustion gas (exhaust gas) rises while swirling.

  At this time, if the jet direction of the combustion burners 21, 22, 23 is directed downward by the angle adjusting mechanism or the amount of combustion air jetted from the furnace bottom air nozzle 30 is reduced, the horizontal direction adjusting device 51 (51 a, 51 a, 51 b, 51 c, 51 d) changes the direction of combustion air injection by the furnace bottom air nozzle 30 (30 a, 30 b, 30 c, 30 d) to the center O side of the furnace 11. Then, an air swirl flow C12 formed by the combustion air from the furnace bottom air nozzle 30 below the flame swirl flow C1 formed by the pulverized coal mixture from the combustion burners 21, 22, 23 and the combustion air. Is formed.

  Since this air swirl flow C12 has a smaller diameter than the flame swirl flow C1, the penetration force of the combustion air from the furnace bottom air nozzle 30 becomes stronger. Therefore, even if the ejection direction of the combustion burners 21, 22, 23 is downward and the flame swirl flow C 1 becomes strong or the amount of combustion air ejected from the furnace bottom air nozzle 30 decreases, Combustion air ejected from the nozzle 30 can easily reach the center of the furnace 11. Then, oxygen shortage is suppressed in the lower center portion of the furnace 11, the unburned portion in the ash remaining at the bottom of the furnace is properly burned, and the unburned portion flowing through the flue 13 is reduced.

  Then, the water supplied from a water supply pump (not shown) is preheated by the economizers 46 and 47, then supplied to a steam drum (not shown) and heated while being supplied to each water pipe (not shown) on the furnace wall. Then, it becomes saturated steam and is sent to a steam drum (not shown). Further, saturated steam of a steam drum (not shown) is introduced into the superheaters 41, 42, and 43 and is heated by the combustion gas. The superheated steam generated by the superheaters 41, 42, 43 is supplied to a power plant (not shown) (for example, a turbine). Further, the steam taken out in the middle of the expansion process in the turbine is introduced into the reheaters 44 and 45, overheated again, and returned to the turbine.

  Thereafter, the exhaust gas that has passed through the economizers 46 and 47 of the flue 13 is subjected to removal of harmful substances such as NOx by a denitration device (not shown) in the gas duct 48, particulate matter is removed by an electric dust collector, After the sulfur is removed, it is discharged from the chimney into the atmosphere.

  As described above, in the boiler according to the first embodiment, the furnace 11 that has a hollow shape and is installed along the vertical direction, and the pulverized coal mixture in which the solid fuel and the combustion air are mixed are placed in the furnace 11. Combustion burners 21, 22, 23 to be ejected, a furnace bottom air nozzle 30 for injecting combustion air into the furnace 11 below the combustion burners 21, 22, 23, and combustion air by the furnace bottom air nozzle 30 And a horizontal direction adjusting device (air jet direction adjusting device) 51 capable of adjusting the jetting direction in the horizontal direction.

  Therefore, if the operating conditions of the boiler 10 change, the combustion air from the furnace bottom air nozzle 30 may not be sufficiently supplied below the pulverized coal mixture from the combustion burners 21, 22, and 23. At this time, the horizontal direction adjusting device 51 adjusts the ejection direction of the combustion air by the furnace bottom air nozzle 30 in the horizontal direction. Therefore, the furnace bottom air nozzle 30 can appropriately supply combustion air necessary for combustion below the position where the pulverized coal mixture is ejected in the furnace 11. As a result, the combustion of the fuel in the furnace 11 can be promoted to suppress the generation of unburned content.

  In the boiler according to the first embodiment, the combustion burners 21, 22, and 23 have an angle adjustment mechanism that can adjust the ejection direction of the pulverized coal mixture in the vertical direction. When the jet direction of the pulverized coal mixture is adjusted to the lower side, the horizontal direction adjusting device 51 changes the jet direction of the combustion air by the furnace bottom air nozzle 30 to the center O side of the furnace 11. Accordingly, when the jet direction of the pulverized coal mixture from the combustion burners 21, 22, and 23 is adjusted to the lower side, the combustion air jetted downward from the blast coal air jet position by the furnace bottom air nozzle 30 is the furnace. It becomes difficult to reach the center of 11. At this time, the horizontal direction adjusting device 51 changes the ejection direction of the combustion air from the furnace bottom air nozzle 30 to the center O side of the furnace 11. Then, the combustion air from the furnace bottom air nozzle 30 can easily reach the center of the furnace 11 below the position where the pulverized coal mixture is ejected, and the fuel can be efficiently burned in the furnace 11. it can.

  In the boiler according to the first embodiment, when the amount of combustion air 30 discharged from the furnace bottom air nozzle decreases, the horizontal direction adjusting device 51 sets the direction of combustion air injection from the furnace bottom air nozzle 30 to the center of the furnace 11. Change to O side. Therefore, when the amount of combustion air ejected from the furnace bottom air nozzle 30 decreases, the combustion air ejected downward from the position where the pulverized coal mixture is ejected from the furnace bottom air nozzle 30 reaches the center of the furnace 11. It becomes difficult. At this time, the horizontal direction adjusting device 51 changes the ejection direction of the combustion air from the furnace bottom air nozzle 30 to the center O side of the furnace 11. Then, the combustion air from the furnace bottom air nozzle 30 can easily reach the center of the furnace 11 below the position where the pulverized coal mixture is ejected, and the fuel can be efficiently burned in the furnace 11. it can.

  In the boiler according to the first embodiment, the horizontal adjustment device 51 adjusts the injection direction of the combustion air by the furnace bottom air nozzle 30 in the horizontal direction separately from the injection direction of the pulverized coal mixture by the combustion burners 21, 22, and 23. It is possible. Therefore, regardless of the ejection direction of the pulverized coal mixture, the ejection direction of the combustion air can be adjusted to the horizontal direction, and even if the combustion state of the furnace 11 fluctuates, the combustion air from the furnace bottom air nozzle 30 Can reach the center of the furnace 11 below the position where the pulverized coal mixture is ejected.

[Second Embodiment]
FIG. 8 is a schematic configuration diagram illustrating a boiler according to the second embodiment. In addition, the same code | symbol is attached | subjected to the member which has the same function as embodiment mentioned above, and detailed description is abbreviate | omitted.

  In the second embodiment, as shown in FIG. 8, a vertical direction adjustment device 52 is provided as an air injection direction adjustment device capable of adjusting the injection direction of combustion air by the furnace bottom air nozzle 30 in the vertical direction. In this case, the vertical direction adjusting device 52 can move and adjust the furnace bottom air nozzle 30 in the vertical direction independently of the combustion burners 21, 22, and 23.

  In the rated operation of the boiler 10, each combustion burner 21, 22, 23 blows pulverized coal mixture and combustion air into the furnace 11, and each furnace bottom air nozzle 30 is located in the furnace 11 below the combustion burner 23. Blow in combustion air. However, the operating condition of the boiler 10 changes as necessary, and the combustion state in the furnace 11 also changes. That is, when the jet direction of the combustion burners 21, 22, 23 is directed downward by the angle adjustment mechanism, the flame swirl flow C <b> 1 in the jet region of the combustion air from the furnace bottom air nozzle 30 becomes strong, and the furnace bottom air nozzle 30 There is a risk that the combustion air that is ejected may not reach the center of the furnace. Further, if the amount of combustion air ejected from the furnace bottom air nozzle 30 decreases, the flow velocity of the combustion air decreases, and the combustion air ejected from the furnace bottom air nozzle 30 may not reach the center of the furnace. There is. Then, the furnace 11 becomes deficient in oxygen at the lower center portion, and the unburned portion in the ash remaining at the bottom of the furnace rises without burning and flows into the flue 13.

  Therefore, in the present embodiment, the arrival of the combustion air ejected from the furnace bottom air nozzle 30 in the lower central region of the pulverized coal mixture ejected from each combustion burner 21, 22, 23 and the combustion air ejection region. When the amount is decreased, the vertical direction adjusting device 52 changes the direction of ejection of the combustion air by the furnace bottom air nozzle 30 to the lower side of the furnace 11.

  Each of the four furnace bottom air nozzles 30 provided at each corner of the furnace 11 is provided with a vertical direction adjusting device 52. Each vertical direction adjusting device 52 can change the ejection direction of the combustion air by the furnace bottom air nozzle 30 to the vertical direction. For example, if the ejection direction of the combustion air from the furnace bottom air nozzle 30 is changed to the lower side of the furnace 11, the jetted combustion air rises after flowing to the lower side of the furnace 11. can do.

  The adjustment angle θ2 in the vertical direction of the furnace bottom air nozzle 30 by the vertical direction adjusting device 52 is 0 degrees to 30 degrees, and preferably 5 degrees to 20 degrees.

  Therefore, when the jet direction of the combustion burners 21, 22, 23 is directed downward by the angle adjustment mechanism or the amount of combustion air jetted from the furnace bottom air nozzle 30 is reduced, The ejection direction of the combustion air from the nozzle 30 is changed to the lower side of the furnace 11. Then, the air swirl formed by the ejection of the combustion air from the furnace bottom air nozzle 30 below the flame swirl flow formed by the pulverized coal mixture from the combustion burners 21, 22 and 23 and the combustion air. A flow is formed.

  Since the combustion air from the furnace bottom air nozzle 30 is ejected to the lower region, it takes time until the combustion air is raised by the upward flow after reaching the center of the furnace 11. The moving distance becomes longer. Therefore, even if the jet direction of the combustion burners 21, 22, 23 is downward and the flame swirl flow becomes strong or the amount of combustion air jetted from the furnace bottom air nozzle 30 decreases, the furnace bottom air nozzle Combustion air ejected from 30 can easily reach the center of the furnace 11. Then, oxygen shortage is suppressed in the lower center portion of the furnace 11, the unburned portion in the ash remaining at the bottom of the furnace is properly burned, and the unburned portion flowing through the flue 13 is reduced.

  As described above, in the boiler according to the second embodiment, the furnace 11 that has a hollow shape and is installed along the vertical direction, and the pulverized coal mixture in which the solid fuel and the combustion air are mixed are placed in the furnace 11. Combustion burners 21, 22, 23 to be ejected, a furnace bottom air nozzle 30 for injecting combustion air into the furnace 11 below the combustion burners 21, 22, 23, and combustion air by the furnace bottom air nozzle 30 And a vertical direction adjusting device (air jet direction adjusting device) 52 capable of adjusting the jet direction of the gas in the vertical direction.

  Therefore, if the operating conditions of the boiler 10 change, the combustion air from the furnace bottom air nozzle 30 may not be sufficiently supplied below the pulverized coal mixture from the combustion burners 21, 22, and 23. At this time, the vertical direction adjusting device 52 adjusts the ejection direction of the combustion air by the furnace bottom air nozzle 30 in the vertical direction. Therefore, the furnace bottom air nozzle 30 can appropriately supply combustion air necessary for combustion below the position where the pulverized coal mixture is ejected in the furnace 11. As a result, the combustion of the fuel in the furnace 11 can be promoted to suppress the generation of unburned content.

  In the boiler according to the second embodiment, the vertical direction adjusting device 52 adjusts the jet direction of the combustion air by the furnace bottom air nozzle 30 in the vertical direction separately from the jet direction of the pulverized coal mixture by the combustion burners 21, 22, and 23. It is possible. Therefore, regardless of the ejection direction of the pulverized coal mixture, the ejection direction of the combustion air can be adjusted to the vertical direction, and even if the combustion state of the furnace 11 fluctuates, the combustion air from the furnace bottom air nozzle 30 Can reach the center of the furnace 11 below the position where the pulverized coal mixture is ejected.

[Third Embodiment]
FIG. 9 is a schematic configuration diagram illustrating a boiler according to the third embodiment. In addition, the same code | symbol is attached | subjected to the member which has the same function as embodiment mentioned above, and detailed description is abbreviate | omitted.

  In 3rd Embodiment, as shown in FIG. 9, the boiler 10 has the furnace 11, the combustion apparatus 12, and the flue 13. As shown in FIG. The combustion device 12 includes a plurality of combustion burners 21, 22, and 23 that are provided below a furnace wall (heat transfer tube) that constitutes the furnace 11. Further, the furnace 11 is provided below the mounting position of the combustion burners 21, 22, and 23 and is provided with a furnace bottom air nozzle 30. Further, the furnace 11 is provided above the mounting positions of the combustion burners 21, 22 and 23 and provided with an additional air nozzle 34.

  And the horizontal direction adjustment apparatus 51 which can adjust the ejection direction of the combustion air by the furnace bottom air nozzle 30 to a horizontal direction, and the vertical direction adjustment which can adjust the ejection direction of the combustion air by the furnace bottom air nozzle 30 to a vertical direction A device 52 is provided.

Further, the furnace 11 is provided with a hopper 61 at the lower end portion, and can store ash and unburned pulverized coal. The furnace 11 is provided with a first unburned amount measuring device 62 that measures the unburned amount of pulverized coal that has fallen to the bottom of the hopper 61. The furnace 11 is provided with a second unburned amount measuring device 63 for measuring the unburned amount of pulverized coal in the exhaust gas downstream of the economizer 47 in the flue 13 in the flow direction of the exhaust gas. For example, a microwave device, a combustion-CO ₂ detector, a laser induction device, or the like may be used as each of the unburned amount measuring devices 62 and 63, and devices other than these devices may be used. The first unburned amount measuring device 62 and the second unburned amount measuring device 63 are connected to the unburned amount analyzing device 64, and the unburned amount analyzing device 64 receives the detection results of the unburned amount measuring devices 62 and 63. Based on this, the increasing / decreasing tendency of the unburned amount in the furnace 11 and the flue 13 is analyzed.

  The control device 65 is connected to the horizontal direction adjustment device 51, the vertical direction adjustment device 52, and the unburned component analysis device 64. The control device 65 can control (feedback control) the operations of the horizontal direction adjusting device 51 and the vertical direction adjusting device 52 according to the analysis result of the unburned component analyzing device 64. Specifically, when the unburned amount of pulverized coal increases, the control device 65 adjusts the ejection direction of the furnace bottom air nozzle 30 using the horizontal direction adjustment device 51 and the vertical direction adjustment device 52.

  Therefore, the combustion burners 21, 22, and 23 blow a pulverized coal mixture and combustion air into the furnace 11 and ignite at this time to form a flame swirl flow. The furnace bottom air nozzle 30 blows combustion air downward from the flame swirl flow in the furnace 11. Then, the pulverized coal mixture and the combustion air are combusted to generate a flame swirl, and the combustion gas (exhaust gas) rises while swirling.

  At this time, if the operating conditions of the boiler 10 are changed, the direction of jetting of the pulverized coal mixture from the combustion burners 21, 22, 23 changes, or the quantity of jetting of combustion air from the furnace bottom air nozzle 30 varies. Or Therefore, the first unburned amount measuring device 62 measures the unburned amount of the pulverized coal that has fallen on the hopper 61 of the furnace 11 and outputs it to the unburned amount analyzing device 64. The second unburned amount measuring device 63 measures the unburned amount of pulverized coal in the exhaust gas flowing through the flue 13 and outputs the measured amount to the unburned component analyzing device 64. The unburned amount analyzing device 64 analyzes the increase / decrease tendency of the unburned amount of pulverized coal based on the detection results of the unburned amount measuring devices 62 and 63 and outputs it to the control device 65. The control device 65 is arranged so that the unburned amount of the pulverized coal dropped on the hopper 61 and the unburned amount of the pulverized coal in the exhaust gas flowing through the flue 13 are reduced according to the analysis result of the unburned component analyzer 64. The ejection direction of the furnace bottom air nozzle 30 is adjusted by the direction adjusting device 51 and the vertical direction adjusting device 52.

  That is, when the amount of unburned coal in the pulverized coal increases, the control device 65 changes the ejection direction of the combustion air from the furnace bottom air nozzle 30 to the center side of the furnace 11 by the horizontal direction adjusting device 51. Then, a small-diameter air swirl flow formed by the combustion air from the furnace bottom air nozzle 30 below the flame swirl flow formed by the pulverized coal mixture from the combustion burners 21, 22 and 23 and the combustion air. And the penetration force of the combustion air from the furnace bottom air nozzle 30 is strengthened. Therefore, the combustion air ejected from the furnace bottom air nozzle 30 can easily reach the center of the furnace 11, oxygen shortage is suppressed at the lower center of the furnace 11, and the unresolved ash remaining in the furnace bottom remains in the ash. The fuel is properly burned and the unburned fuel flowing through the flue 13 is reduced.

  Further, when the amount of unburned coal in the pulverized coal increases, the control device 65 changes the ejection direction of the combustion air from the furnace bottom air nozzle 30 to the lower side of the furnace 11 by the vertical direction adjusting device 52. Then, the air swirl formed by the ejection of the combustion air from the furnace bottom air nozzle 30 below the flame swirl flow formed by the pulverized coal mixture from the combustion burners 21, 22 and 23 and the combustion air. A flow is formed, and it takes time until the combustion air reaches the center of the furnace 11 and is raised by the upward flow, and the moving distance at this time becomes long. Therefore, the combustion air ejected from the furnace bottom air nozzle 30 can easily reach the center of the furnace 11, oxygen shortage is suppressed at the lower center of the furnace 11, and the unresolved ash remaining in the furnace bottom remains in the ash. The fuel is properly burned and the unburned fuel flowing through the flue 13 is reduced.

  In this case, the control device 65 operates the horizontal adjustment device 51 or the vertical adjustment device 52 when the amount of unburned pulverized coal increases, but operates both the horizontal adjustment device 51 and the vertical adjustment device 52. May be.

  As described above, in the boiler according to the third embodiment, the first unburned amount measuring device 62 that measures the unburned amount of the pulverized coal falling on the bottom of the furnace 11, and the exhaust gas flowing from the furnace 11 to the flue 13. A second unburned amount measuring device 63 that measures the unburned amount, and a control device 65 that operates the horizontal direction adjusting device 51 and the vertical direction adjusting device 52 according to the measurement results of the unburned amount measuring devices 62 and 63. Provided.

  Therefore, the control device 65 uses the horizontal adjustment device 51 and the vertical adjustment device 52 to adjust the bottom air nozzle according to the unburned amount of pulverized coal that has fallen to the bottom of the furnace 11 and the unburned amount of the exhaust gas flowing through the flue 13. The direction of jetting of combustion air from 30 is adjusted, and the combustion air from the furnace bottom air nozzle 30 can reach the center of the furnace 11 below the jetting position of the pulverized coal mixture. The generation of unburned coal can be suppressed.

  In the third embodiment described above, the control device 65 can adjust the horizontal direction adjustment device 51 and the vertical direction adjustment device 52. However, the present invention is not limited to this configuration. For example, the operator manually adjusts the horizontal direction adjustment device 51 and the vertical direction adjustment device 52 according to the unburned amount of pulverized coal falling on the bottom of the furnace 11 and the unburned amount of exhaust gas flowing through the flue 13. Also good.

  Further, in the above-described embodiment, when the jet direction of the pulverized coal mixture from the combustion burners 21, 22, 23 is adjusted to the lower side, or the amount of combustion air ejected from the furnace bottom air nozzle 30 decreases. In this case, the configuration is such that the direction in which the combustion air is ejected by the furnace bottom air nozzle 30 is changed. However, the present invention is not limited to this configuration. For example, it is effective to change the ejection direction of the combustion air from the furnace bottom air nozzle 30 in the operating state of the boiler 10 in which the combustion air from the furnace bottom air nozzle 30 is difficult to reach the center of the furnace 11.

  In the above-described embodiment, the three-stage combustion burners 21, 22, and 23 are set for the furnace 11, but the number may be two or four or more. Further, the number of pulverizers 27, 28, 29 is not limited to the embodiment.

  In the above-described embodiment, the boiler of the present invention is a coal-fired boiler, but the solid fuel may be a boiler using biomass, petroleum coke, petroleum residue, or the like in addition to coal.

DESCRIPTION OF SYMBOLS 10 Boiler 11 Furnace 12 Combustion device 13 Flue 21, 22, 23 Combustion burner 24, 25, 26 Pulverized coal supply pipe 27, 28, 29 Crusher 30 Furnace bottom air nozzle 31 Wind box 32 Air duct 34 Additional air nozzle 41, 42,43 Superheater (heat exchanger)
44, 45 Reheater (heat exchanger)
46, 47 economizer (heat exchanger)
51 horizontal direction adjusting device 52 vertical direction adjusting device 61 hopper 62 first unburned amount measuring device 63 second unburned amount measuring device 64 unburned amount analyzing device 65 control device

Claims (8)

A furnace that is hollow and installed along the vertical direction;
A combustion burner for injecting fuel gas mixed with solid fuel and combustion air into the furnace;
A bottom air nozzle for injecting combustion air into the furnace below the combustion burner in a vertical direction;
An air ejection direction adjusting device capable of adjusting the ejection direction of combustion air by the furnace bottom air nozzle in a horizontal direction or a vertical direction;
A boiler characterized by comprising.   The combustion burner has an angle adjustment mechanism capable of adjusting a fuel gas injection direction to a vertical direction, and when the fuel gas injection direction from the combustion burner is adjusted downward by the angle adjustment mechanism, the air burner 2. The boiler according to claim 1, wherein the jet direction adjusting device changes a jet direction of combustion air by the furnace bottom air nozzle to a center side of the furnace or a lower side of the furnace.   When the amount of ejection of combustion air from the furnace bottom air nozzle decreases, the air ejection direction adjusting device sets the ejection direction of combustion air by the furnace bottom air nozzle to the center side of the furnace or the lower side of the furnace The boiler according to claim 1, wherein the boiler is changed to   The all-air ejection direction adjusting device has a horizontal direction adjusting device capable of adjusting the ejection direction of the combustion air by the furnace bottom air nozzle in the horizontal direction separately from the ejection direction of the fuel gas by the combustion burner. The boiler according to any one of claims 1 to 3.   The air jet direction adjusting device includes a vertical direction adjusting device capable of adjusting a jet direction of combustion air by the furnace bottom air nozzle in a vertical direction separately from a jet direction of fuel gas by the combustion burner. The boiler according to any one of claims 1 to 4.   A first unburned amount measuring device that measures the unburned amount of the solid fuel that has fallen to the bottom of the furnace is provided, and operates the air ejection direction adjusting device according to the measurement result of the first unburned amount measuring device. The boiler as described in any one of Claims 1-5 characterized by the above-mentioned.   A second unburned amount measuring device for measuring an unburned amount of exhaust gas flowing from the furnace to the flue is provided, and the air ejection direction adjusting device is operated according to a measurement result of the second unburned amount measuring device; The boiler as described in any one of Claims 1-5 characterized by these.   7. When the unburned amount increases, the air jet direction adjusting device changes the jet direction of combustion air from the furnace bottom air nozzle to the center side of the furnace or the lower side of the furnace. Or the boiler of Claim 7.

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