JP2017215059A - Fluidized bed boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluidized bed boiler in a fuel chute method, enabling more uniform supply of fuel to an entire fluidized bed and reduction of cost of manufacturing, operation and the like.SOLUTION: A fluidized bed boiler includes: a combustion chamber supplied with fluidization gas to form a fluidized bed therein; a fuel supply port provided on a wall surface of the combustion chamber; a fuel chute passage connected to the fuel supply port to supply fuel into the combustion chamber via the fuel supply port and having a bottom surface that is arranged horizontally or downwards from the horizontal direction at a connection portion with the fuel supply port; and at least one indoor injection portion provided on the wall surface of the combustion chamber on the lower side of the fuel supply port and injecting conveyance gas to the combustion chamber horizontally or upwards from the horizontal direction.SELECTED DRAWING: Figure 1A

Description

  The present disclosure relates to a fluidized bed boiler, and more particularly, to an improvement in a fuel supply device that supplies fuel to a combustion chamber by a fuel chute method.

  In recent years, fluidized bed boilers with excellent environmental compatibility using recycled fuel as an alternative to fossil fuels have been widely used. For example, a bubbling fluidized bed boiler forms a fluidized bed (fluidized bed) by turning a fluidized material (silica sand) filled in the bottom of a combustion chamber into a fluidized state by blowing high pressure fluidized gas from below. The fuel input to the fluidized bed is instantly dried and incinerated. Recycled fuel is woody biomass such as wood chips, waste tires, sludge, RPF (Refuse Paper and Plastic Fuel), etc., and it has relatively much moisture compared to fossil fuels, and its shape, size, and weight. And so on.

By the way, the fuel supply to the combustion chamber of the fluidized bed boiler is performed by various methods such as a fuel chute method and a spreader method. In any of these fuel supply methods, fuel is supplied to the entire fluidized bed formed in the combustion chamber. Has been devised to uniformly supply (Patent Document 1). This is because variations in the amount of fuel input in the fluidized bed as a whole lead to fluctuations in the temperature of the combustion gas and the like, as well as variations in the oxygen (O ₂ ) concentration in the combustion gas, and generate harmful gases such as dioxins and NOx. Because it causes. In particular, when the O ₂ concentration is lowered, a large amount of carbon monoxide (CO) is generated, which causes generation of dioxins having a high correlation with the CO concentration. Specifically, in the fuel chute method, fuel is supplied from a plurality of locations on the wall surface of the combustion chamber by a distributor. For example, in Patent Document 1, a dispersion plate is provided in the vicinity of a fuel supply port of a transfer pipe that conveys fuel toward a fuel supply port of a combustion chamber, and a number of branch channels are formed by a number of partition walls formed on the distribution plate. The fuel is divided evenly. In the spreader system, the fuel arrival position (flying distance) in the fluidized bed is changed by the rotating blades (rotors), so that the fuel is uniformly supplied to the entire fluidized bed. In addition, as disclosed in Patent Document 2, there is a configuration in which the tip of a fuel supply pipe that supplies fuel to the combustion chamber from above the fluidized bed can be swung in a desired direction at a constant cycle. .

  Moreover, although the fuel of said patent document 1 is coal, there exist patent documents 3-4 as a fluidized bed boiler using a recycled fuel, for example. In Patent Document 3, a blade having the same uneven shape is provided on the outer periphery of the rotor of the spreader in order to enable the distributed supply of the high water content residue such as sludge, which is difficult to supply evenly with the rotor of the conventional spreader, to the fluidized bed. It is disclosed that a plurality of rotors are provided at a predetermined pitch in the circumferential direction of the rotor. In Patent Document 4, the structure provided by protruding from the wall surface toward the fluidized bed from the fuel supply port on the wall surface of the combustion chamber allows the fuel having a low density such as wood chips and waste plastic to be blown upward from the fluidized bed. It is disclosed to prevent the air from being wound up by air and to ensure that the fluidized material and the fuel are mixed.

JP 59-173626 A JP 59-139743 A Japanese Patent Laid-Open No. 02-213609 JP 2004-85064 A

Among the various fluidized bed fuel supply systems as described above, for example, the spreader system is suitable for coal fuel, but when recycled fuel is used, the amount of water is not sufficient or the size is uneven. There is concern about the resulting fuel clogging. On the other hand, the fuel chute method is the most suitable in terms of adapting to such various fuels and simplifying the equipment, but because of the supply method by gravity drop, compared to the spreader method, the entire fluidized bed On the other hand, it is difficult to supply fuel uniformly.
In order to solve this point, a method of providing a dispersion plate in which a diversion channel is formed in a fuel chute as in Patent Document 1 is conceivable. However, similar to the spreader method, this is due to the properties of the above recycled fuel. Therefore, there is a concern that the fuel will be clogged in the diversion channel. In addition, when the number of fuel chute paths is increased, the fuel can be uniformly supplied to the entire fluidized bed, while fuel supply and transportation equipment such as a fuel chute path and a conveyor connected to each fuel chute path are provided. Therefore, the number of fuel chute paths is desired to be as small as possible.

  In view of the above circumstances, at least one embodiment of the present invention provides a fluidized bed boiler capable of more uniformly supplying fuel to the entire fluidized bed and reducing costs for manufacturing and operation in the fuel chute method. The purpose is to provide.

(1) A fluidized bed boiler according to at least one embodiment of the present invention,
A combustion chamber that forms a fluidized bed by supplying fluidized gas;
A fuel supply port provided on a wall surface of the combustion chamber;
A fuel chute path connected to the fuel supply port for supplying fuel to the inside of the combustion chamber via the fuel supply port, wherein the gradient of the bottom surface of the fuel chute path is connected to the fuel supply port A fuel chute path that faces the combustion chamber toward the combustion chamber or downwards with respect to the horizontal in the section;
An indoor injection unit that is provided below the fuel supply port in the wall surface of the combustion chamber and injects a carrier gas toward the combustion chamber in the horizontal or horizontal direction upward.

  According to the configuration of (1) above, the indoor injection section that injects the carrier gas toward the combustion chamber is provided below the fuel supply port in the wall surface of the fluidized bed boiler, The fuel supplied from the fuel supply port to the combustion chamber falls on the transfer gas injected from the indoor injection unit. At this time, in order to convey the fuel toward the distant place, the carrier gas is injected not horizontally or downwardly to boost the fall of the fuel but horizontally or above the horizontal. For this reason, fuel (recycled fuel) that is not uniform in weight or size is transported by the carrier gas injected from the indoor injection section for a distance corresponding to the size and weight of the fuel, and falls to the fluidized bed. To do. Thereby, a fuel can be supplied more uniformly over the whole fluidized bed. Thereby, more uniform combustion of the fuel in the fluidized bed can be realized, and generation of NOx and CO can be suppressed. Further, in order to uniformly supply the fuel to the entire fluidized bed, for example, it is less expensive to install the indoor injection unit than to install a plurality of fuel chute paths on the wall surface of the combustion chamber. Costs required for production and operation (maintenance) of fluidized bed boilers because the scale of fuel supply and transportation equipment such as a conveyor connected to the fuel chute path and a distribution unit for distributing fuel to the fuel chute path can be reduced. Can be greatly reduced.

(2) In some embodiments, in the configuration of (1) above,
The conveying gas is steam generated in the fluidized bed boiler.
According to the configuration of (2) above, the steam (self-steam) of the fluidized bed boiler does not contribute to the combustion reaction in the combustion chamber, and therefore does not burn and disappear during the transportation of fuel. For this reason, fuel can be distributed and supplied throughout the fluidized bed more reliably than when air is injected from the indoor injection section.

(3) In some embodiments, in the above configurations (1) to (2),
The indoor injection unit includes a plurality of injection ports arranged on the wall surface adjacent to each other in the horizontal direction.
According to the configuration of (3) above, the plurality of injection ports are arranged adjacent to each other in the horizontal direction below the fuel supply port on the wall surface of the combustion chamber. As a result, it is possible to form a state where the carrier gas having the momentum due to injection exists below the fuel supply port over a wider range, so that the fuel that pops out from the fuel supply port can be more reliably transferred to the carrier gas. Can be dropped and transported.

(4) In some embodiments, in the above configuration (1) or (2),
The indoor injection unit is
An upper jet group consisting of a plurality of jets arranged on the wall surface adjacent to each other in the horizontal direction;
A lower injection port group consisting of a plurality of injection ports arranged on the wall surface in the horizontal direction below the upper injection port group,
Each of the injection ports constituting the upper injection port group is configured to inject the carrier gas at a first injection speed,
Each of the injection ports constituting the lower injection port group is configured to inject the carrier gas at a second injection speed that is an injection speed force faster than the first injection speed.
According to the configuration of (4) above, the jetting speed (second jetting speed) of the carrier gas from each of the jets constituting the lower jet group is the same as that from each of the jets constituting the upper jet group. It is stronger than the jetting speed (first jetting speed) of the conveying gas. Thus, by increasing the injection speed of the lower stage from the upper stage in the vertical direction, the fuel can be distributed and supplied over the entire fluidized bed by the indoor injection unit.

(5) In some embodiments, in the above configurations (3) to (4),
Each of the plurality of ejection ports is configured such that ejection ranges of the transfer gas ejected from the ejection ports adjacent to each other overlap each other on a horizontal plane.
According to the configuration of the above (5), the gap generated between the carrier gases ejected from each of the plurality of injection ports can be reduced, and the state where the carrier gas exists can be formed in a wider range. The fuel popping out from the fuel supply port can be reliably dropped onto the transport gas and transported.

(6) In some embodiments, in the above configurations (3) to (5),
And an injection speed control device that periodically changes an injection force of the transfer gas from each of the plurality of injection ports.
According to the configuration of the above (6), when the injection force is large, the fuel can be conveyed further than when the injection force is small, and along with the periodic change of the injection force, the fuel The flight distance of the fuel from the supply port can be changed. As a result, the fuel can be supplied with better dispersion throughout the fluidized bed.

(7) In some embodiments, in the above configurations (1) to (6),
In the bottom surface of the fuel chute path, an in-channel injection port for injecting the mixing gas in a direction orthogonal to the bottom surface of the fuel chute path or in a direction lower than the orthogonal direction is formed.
According to the configuration of (7) above, the blocky fuel can be destroyed by the mixing gas injected from the in-road injection port, and the fuel can be dispersed (dispersed) inside the fuel chute path (space). . In this way, the fuel that has been removed from the lump state in the inside of the fuel chute path and easily scattered is easily transported by the transport gas, so that the fuel can be better dispersed throughout the fluidized bed.

(8) In some embodiments, in the configurations of (1) to (7) above,
A protrusion is formed on the bottom surface of the fuel chute path.
According to the configuration of (8) above, when the fuel chute is dropped, the blocky fuel can be broken by the bounce caused by passing through the protruding portion, and the fuel is scattered in the fuel chute (space). Distributed). In this way, the fuel that has been removed from the lump state in the inside of the fuel chute path and easily scattered is easily transported by the transport gas, so that the fuel can be better dispersed throughout the fluidized bed.

(9) In some embodiments, in the above configurations (1) to (8),
On the bottom surface of the fuel chute path, a drop direction convex portion is formed extending over a predetermined range along the fuel drop direction,
The drop direction convex portion inclines downward from the top toward both sides in the cross-sectional shape.
According to the configuration of (9) above, the drop direction convex portion has a top portion and an inclined portion that inclines downward from the top portion toward both sides. The fuel that has traveled straight along the fuel chute path passes through the inclined portion of the drop-direction convex portion, and receives a force in the left-right direction with respect to the drop direction due to the inclination of the inclined portion. As a result, when the fuel jumps out from the fuel supply port into the combustion chamber, the fuel can be dispersed so as to spread left and right, and the fuel can be better dispersed and supplied throughout the fluidized bed. Moreover, the number of fuel chute paths can be reduced by jumping out from the fuel supply port so that the fuel spreads left and right.

(10) In some embodiments, in the configuration of (9) above,
The drop direction convex portion is configured such that the height of the top portion gradually increases downward in the fuel drop direction over the predetermined range.
According to the configuration of (10) above, the drop direction convex portion is arranged on the bottom surface of the fuel chute path so as not to cause a step at the connection point between the end of the drop direction convex portion on the upstream side of the fuel chute path and the bottom surface of the fuel chute path. It is possible to prevent the fuel chute path from being clogged with fuel.

  According to at least one embodiment of the present invention, in a fuel chute system, a fluidized bed boiler is provided in which fuel can be supplied more uniformly to the entire fluidized bed and costs for manufacturing, operation, and the like can be reduced.

It is the cross-sectional schematic diagram which looked at the combustion chamber of the fluidized bed boiler which concerns on one Embodiment of this invention from the side with respect to the wall surface provided with the fuel supply port, and embodiment using fluidized gas for the gas for conveyance FIG. 1 is a schematic cross-sectional view of a combustion chamber of a fluidized bed boiler according to an embodiment of the present invention as viewed from the side with respect to a wall surface provided with a fuel supply port, and shows an embodiment using steam as a carrier gas. It is. It is a schematic diagram which shows a part of wall surface of the combustion chamber in which the fuel supply port which concerns on one Embodiment of this invention was provided, and is the figure seen from the A direction of FIG. 1A-FIG. 1B, and an indoor injection part has several Consists of injection ports. It is a schematic diagram which shows a part of wall surface of the combustion chamber in which the fuel supply port which concerns on one Embodiment of this invention was provided, and is the figure seen from the A direction of FIG. 1A-FIG. 1B, and has one indoor injection part. Consists of injection ports. It is a schematic diagram of the section (BB section) which cut the combustion chamber concerning one embodiment of the present invention with the horizontal plane which passes through an indoor jetting part, and the lower part of the arbitrary fuel chute way was seen from the B direction of Drawing 1A-Drawing 1B FIG. It is a schematic diagram which shows a part of wall surface of the combustion chamber provided with the fuel supply port which concerns on one Embodiment of this invention, and shows several injection nozzles which consist of an upper stage injection nozzle group and a lower stage injection nozzle group. It is a schematic diagram which shows a part of wall surface of the combustion chamber provided with the fuel supply port which concerns on one Embodiment of this invention, and an upper stage injection nozzle group and a lower stage injection nozzle group consist of one injection nozzle each. It is a mimetic diagram showing a section of a part of fuel chute way connected to a combustion chamber concerning one embodiment of the present invention, and is a figure which expanded a connection part neighborhood. It is the schematic diagram which looked at a part of bottom face of the fuel chute path connected to the combustion chamber which concerns on one Embodiment of this invention from upper direction. It is a figure for demonstrating the protrusion part formed in the fuel chute path which concerns on one Embodiment of this invention, and is the schematic diagram which looked at the one part cross section of the fuel chute path from the front of the combustion chamber. It is a figure for demonstrating the protrusion part formed in the fuel chute path which concerns on one Embodiment of this invention, and is the schematic diagram which looked at the one part cross section of the fuel chute path from the front of the combustion chamber. It is a schematic diagram for demonstrating the dropping direction convex part provided in the fuel chute path which concerns on one Embodiment of this invention, (a) Front view, (b) Side view, (c) It is a top view. .

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. Absent.
For example, expressions expressing relative or absolute arrangements such as “in a certain direction”, “along a certain direction”, “parallel”, “orthogonal”, “center”, “concentric” or “coaxial” are strictly In addition to such an arrangement, it is also possible to represent a state of relative displacement with an angle or a distance such that tolerance or the same function can be obtained.
For example, an expression indicating that things such as “identical”, “equal”, and “homogeneous” are in an equal state not only represents an exactly equal state, but also has a tolerance or a difference that can provide the same function. It also represents the existing state.
For example, expressions representing shapes such as quadrangular shapes and cylindrical shapes represent not only geometrically strict shapes such as quadrangular shapes and cylindrical shapes, but also irregularities and chamfers as long as the same effects can be obtained. A shape including a part or the like is also expressed.
On the other hand, the expressions “comprising”, “comprising”, “comprising”, “including”, or “having” one constituent element are not exclusive expressions for excluding the existence of the other constituent elements.

  FIG. 1A is a schematic cross-sectional view of a combustion chamber 2 of a fluidized bed boiler 1 according to an embodiment of the present invention as viewed from the side with respect to a wall surface 21 provided with a fuel supply port 3. It is a figure which shows embodiment using fluidization gas Ga. FIG. 1B is a schematic cross-sectional view of the combustion chamber 2 of the fluidized bed boiler 1 according to an embodiment of the present invention as viewed from the side with respect to the wall surface 21 provided with the fuel supply port 3. It is a figure which shows embodiment using steam. 2A to 2B are schematic views showing a part of the wall surface 21 of the combustion chamber 2 in which the fuel supply port 3 is provided, and correspond to the views seen from the A direction in FIGS. 1A to 1B. FIG. 3 is a schematic view of a cross section (BB cross section) obtained by cutting the combustion chamber 2 according to an embodiment of the present invention along a horizontal plane passing through the indoor injection unit 5, and shows a lower portion of an arbitrary fuel chute path 4. It corresponds to the figure seen from the B direction of 1A-FIG. 1B. The fluidized bed boiler 1 shown in FIGS. 1A to 3 is a bubble fluidized bed boiler.

As shown in FIGS. 1A to 3, the fluidized bed boiler 1 includes a combustion chamber 2, a fuel supply port 3, a fuel chute path 4, and an indoor injection unit 5. As will be described later, fuel is supplied to the fluidized bed boiler 1 by a fuel chute method, and fuel F is supplied from the fuel supply port 3 to the combustion chamber 2 through the fuel chute passage 4. Further, in the fluidized bed boiler 1, the fuel F is burned at a low air ratio in the fluidized bed L formed by primary air (fluidized gas Ga) in order to suppress the generation of harmful gases such as NOx, CO, and dioxins. At the same time, the exhaust gas generated by the combustion in the fluidized bed L is combusted at a high air ratio by the secondary air Gb supplied from above the fluidized bed L to the combustion chamber 2. The high-temperature exhaust gas discharged from the combustion chamber 2 is heat-exchanged in the heat transfer tube group 12 such as a superheater or a economizer disposed downstream of the combustion chamber 2, and the heat energy recovered from the heat exchange is generated by power generation. Used for etc. Said superheater may be installed in the fluidized bed L, and heat exchange with the heat by the combustion in the fluidized bed L is carried out in a superheater. The thermal energy recovered from the heat exchange is used for power generation and the like. For example, steam generated by the superheater is sent to a turbine (not shown) or the like.
Hereinafter, each of the above-described configurations of the fluidized bed boiler 1 will be described. In the drawing, the lower part of the vertical direction V coincides with the direction of gravity, and the horizontal direction H is a horizontal plane direction orthogonal to the vertical direction V.

  The combustion chamber 2 forms a fluidized bed L by being supplied with the fluidizing gas Ga. As illustrated in FIG. 1A to FIG. 1B, the combustion chamber 2 is installed to stand upright and accommodates a predetermined amount of fluidized material (inert particles such as dredged sand or a desulfurizing agent such as limestone). In addition, an air nozzle (not shown) for supplying fluidized gas Ga (primary air) is provided at the bottom 22 of the combustion chamber 2. Then, by supplying fluidized gas Ga from the bottom 22 of the combustion chamber 2 so as to blow up into the combustion chamber 2, the fluidized material floats to a predetermined height and forms a fluidized bed L (fluidized bed) while moving violently. To do. The supplied fluidized gas Ga may be blown up through a wind chamber (not shown) or a perforated plate provided in the bottom 22.

  In the embodiment shown in FIGS. 1A to 3, in the combustion chamber 2, the fluidized gas Ga is used to reduce the fluidized bed L to a reduced state (a state in which oxygen is low) and to a temperature such as 800 ° C. to 850 ° C. While maintaining the generation of NOx by maintaining the secondary air Gb from above the fluidized bed L, CO is removed by the temperature region of 800 degrees or more formed above the fluidized bed L, and the generation of harmful substances Is suppressed. The fluidizing gas Ga is supplied to the combustion chamber 2 via the primary air supply pipe 13. The secondary air Gb is supplied to the secondary air introduction nozzle 15 provided on the wall surface 21 of the combustion chamber 2 by the secondary air supply pipe 14 branched from the primary air supply pipe 13. To the inside of the combustion chamber 2. 1A to 1B show one secondary air introduction nozzle 15, a plurality of secondary air introduction nozzles 15 are provided on the wall surface (wall surface 21, opposing wall surface 23, etc.) of the combustion chamber. Thus, the secondary air Gb may be supplied as overfire air (OFA) or additional air (AA).

  The fuel supply port 3 is provided on the wall surface 21 of the combustion chamber 2. In other words, the fuel supply port 3 is an opening formed in the wall surface 21 so as to communicate the inside and the outside of the combustion chamber 2. The fuel supply port 3 is provided above the upper surface of the fluidized bed L formed inside the combustion chamber 2 such as about 1 to 2 m, and the fuel F is supplied into the combustion chamber 2 from the fuel supply port 3. Is done. The fuel F of the fluidized bed boiler 1 includes woody biomass such as wood chips, waste tires, sludge, RPF (Refuse Paper and Plastic Fuel), and the like (recycled fuel). The fuel F supplied from the fuel supply port 3 to the combustion chamber 2 repeatedly violently collides with the fluidized material in the fluidized bed L and burns effectively. In the embodiment shown in FIGS. 1A to 3, the fuel supply port 3 has an oval shape for connecting a cylindrical fuel chute passage 4 as will be described later, and the major axis of the oval is in the vertical direction V. It is provided in the wall surface 21 of the combustion chamber 2 so that it may follow (refer FIG. 2A-FIG. 2B).

  The fuel chute path 4 is connected to the fuel supply port 3 and is a passage for supplying the fuel F into the combustion chamber 2 through the fuel supply port 3. As shown in FIG. 1A to FIG. 3, the fuel chute path 4 has a cavity therein to form a fuel F passage. Further, as shown in FIGS. 1A to 3, the gradient of the bottom surface 41 of the fuel chute path 4 is directed toward the combustion chamber 2 at the connection portion 31 with the fuel supply port 3 or downward with respect to the horizontal. . Specifically, the fuel chute path 4 extends linearly upward from the connecting portion (connecting portion 31) connected to the edge of the fuel supply port 3 at a predetermined installation angle θs with respect to the horizontal direction H. , Connected to the wall surface 21 of the combustion chamber 2. Thus, the fuel chute path 4 has a gradient with respect to the horizontal direction H, and the gradient of the bottom surface 41 of the fuel chute path 4 is directed toward the combustion chamber 2 at the connection portion 31 with the fuel supply port 3. It faces downward with respect to the horizontal. In other words, when the extension line 41e along the bottom surface 41 of the fuel chute path 4 is drawn toward the inside of the combustion chamber 2 in a side view as shown in FIGS. It faces downward with respect to H. In this manner, the fuel chute path 4 is installed on the wall surface 21 of the combustion chamber 2 so as to be inclined at an angle, so that the fuel F introduced from the inlet on the upstream side of the fuel chute path 4 (not shown) is shown in FIG. As indicated by an arrow (falling direction Fd) in FIG. 1B, the fuel falls by gravity so as to slide down inside the fuel chute 4 and is supplied into the combustion chamber 2 from the fuel supply port 3 on the downstream side. The installation angle θs of the fuel chute path 4 is an angle at which the fuel ch F 4 falls without clogging the fuel chute 4 in consideration of the properties and shape of the fuel F. In the embodiment shown in FIGS. 1A to 3, the fuel chute path 4 has a cylindrical shape, the cross section of the bottom surface 41 of the fuel chute path 4 has an arc shape, and the extension line 41 e described above is The fuel chute 4 is drawn along the lower end 41b (the end located at the lowest position in the vertical direction V) of the bottom surface 41 having an arcuate cross section. In addition, one end of the fuel chute path 4 is processed into an oval shape because it is cut obliquely at the installation angle θs in order to connect to the fuel supply port 3 at the installation angle θs.

  The indoor injection unit 5 is provided above the fluidized bed L and below the fuel supply port 3 in the wall surface 21 of the combustion chamber 2, and is directed toward the combustion chamber 2 horizontally or upwardly with respect to the transfer gas G <b> 1. Inject. In other words, the indoor injection unit 5 is an opening formed in the wall surface 21 so as to communicate the inside and the outside of the combustion chamber 2, and falls so as to jump out of the fuel supply port 3 into the combustion chamber 2. In order to transport the coming fuel F to a position further away from the fuel supply port 3 (fly away), a transport gas G1 is injected. Further, by directing the injection direction of the transport gas G1 horizontally or upward, the fuel F can be transported further away without boosting the fall of the fuel F by the transport gas G1. It is possible. More specifically, as shown in FIGS. 1A to 1B, the fuel F falls by gravity toward the fluidized bed L in the direction of dropping from the fuel chute 4 and jumping out from the fuel supply port 3. At this time, since the transport gas G1 is injected above the fluidized bed L, before reaching the fluidized bed L, the transport gas G1 ejected from the indoor ejection unit 5 is preceded by an ejection range R (described later). To reach. As a result, the fuel F is blown further along the injection direction of the carrier gas G1 further away from the point of dropping of the fluidized bed L when there is no carrier gas G1, and the fuel F falls in the fluidized bed L. The point is changed by the transfer gas G1.

  In the embodiment shown in FIGS. 1A to 3, the injection direction and the injection force are adjusted so that the fuel F can be blown to the vicinity of the opposing wall surface 23 of the wall surface 21 provided with the fuel supply port 3. Yes. This eliminates the need to provide the fuel chute path 4 on the opposing wall surface 23. For this reason, the fuel chute path 4 is not provided on the opposing wall surface 23 (see FIGS. 1A to 1B). Further, the transfer gas G1 is prepared by connecting the primary air supply pipe 13 for supplying the fluidizing gas Ga to the combustion chamber 2 and the indoor injection unit 5 via the gas transfer pipe 52 ( (See FIG. 1A).

  Moreover, in embodiment shown by FIG. 1A-FIG. 3, as FIG. 2A and FIG. 3 show, the indoor injection part 5 is comprised by the several injection port 5a. Further, as shown in FIG. 2A, a plurality of injection ports 5a are arranged on the wall surface 21 of the combustion chamber 2 adjacent to the horizontal direction H (three in the illustration of FIGS. 2A and 3). More specifically, in the illustration of FIG. 3, the plurality of injection ports 5 a are provided in the range from the short axis end to the lower end of the elliptical fuel supply port 3, and below the fuel supply port 3. The entire area is covered by the ejection range R of the transfer gas G1. Moreover, the gas conveyance pipe | tube 52 for supplying the gas G1 for conveyance is connected to each injection port 5a. In the illustration of FIG. 3, the number of gas transport pipes 52, which is only one halfway, is branched from the middle by the number of injection ports 5 a provided in the combustion chamber 2, and is connected to all the injection ports 5 a. And the gas G1 for conveyance is comprised so that it may be ejected from each injection port 5a, after flowing through the gas conveyance pipe | tube 52 to the injection port 5a. Since the transfer gas G1 is injected from the plurality of injection ports 5a in this way, a state in which the transfer gas G1 having a momentum due to injection exists below the fuel chute path 4 can be formed over a wide range. Thus, the fuel F jumping out from the fuel supply port 3 can be more reliably dropped and transferred onto the transfer gas G1. In addition, the number of the injection ports 5a should just be 1 or more. For example, when the number of the injection ports 5a is one, as shown in FIG. 2B, the indoor injection unit 5 has an injection range R of the transfer gas G1 from one injection port 5a. It may be provided so as to cover the entire area below the bottom.

  Further, in the embodiment shown in FIGS. 1A to 3, the one or more injection ports 5 a configuring the indoor injection unit 5 are each configured by an outlet of a nozzle (indoor injection nozzle 51), and the gas transport pipe 52. Is configured to inject the carrier gas G <b> 1 supplied from the indoor injection nozzle 51 into the combustion chamber 2. The injection direction, the injection amount, and the injection speed of the carrier gas G1 are adjusted according to the shape, installation angle, and the like of the indoor injection nozzle 51. In some other embodiments, the carrier gas G1 may be injected horizontally or the like from the injection port 5a without providing the indoor injection nozzle 51. The injection angle of the injection port 5a with respect to the horizontal direction H may be set to any angle in the range of 0 degree to 45 degrees. The above 45 degrees is theoretically the most distant in a simple model. It becomes the value illustrated as a possible angle. As a result, particularly in a bubble fluidized bed boiler, if the injection angle is increased too much, a relatively small fuel out of various fuels supplied from the fuel supply port 3 is blown up by the carrier gas G1. By preventing the occurrence of such a situation, it is possible to prevent a decrease in combustion efficiency.

  Further, the injection amount and the injection speed of the transfer gas G1 from the indoor injection unit 5 may be adjusted by other methods regardless of the presence or absence of the indoor injection nozzle 51. For example, a damper 55 (valve) may be provided in the gas transport pipe 52 and the adjustment may be made according to the opening degree of the damper 55. A blower (not shown) that blows the carrier gas G <b> 1 toward the indoor injection unit 5 may be provided in the gas transport pipe 52, and the output of the blower may be adjusted. Alternatively, the fluidized bed boiler 1 may further include an injection control device 56 that can control the injection of the transfer gas G1 from the indoor injection unit 5 (each of the plurality of injection ports 5a) (see FIG. 3). For example, the injection control device 56 is connected to a device capable of adjusting the injection amount and the injection speed from the indoor injection unit 5 such as the damper 55 and the blower (not shown) (the damper 55 in FIG. 3). You may change an opening degree, the output of an air blower (not shown), etc. periodically, for example. When the injection speed is high, the fuel can be conveyed further than when the injection speed is low, and the flight distance of the fuel F from the fuel supply port 3 is changed in accordance with the periodic change of the injection speed. be able to. In addition, when the injection amount is large, more fuel can be transported than when the injection amount is small, and the transport amount of the fuel F from the fuel supply port 3 is reduced as the injection amount changes periodically. Can be changed. Or you may adjust the injection quantity and the injection speed of the gas G1 for conveyance of the indoor injection part 5 by combining these two or more.

  Although one fuel chute path 4 is shown in FIGS. 1A to 3, the number of fuel chute paths 4 connected to the combustion chamber 2 may be one or more. When a plurality of fuel chute paths 4 are provided, a plurality of fuel supply ports 3 are provided on the wall surface 21 of the combustion chamber 2, and the fuel chute paths 4 are connected to the respective fuel chute paths 4. Further, the wall surface 21 on which the fuel supply port 3 and the fuel chute path 4 are provided is not limited to one, and may be two opposing surfaces, two adjacent surfaces, or all surfaces. good. The number that can be installed on one wall surface 21 of the fuel chute path 4 also depends on the size of the combustion chamber 2. For example, in the embodiment shown in FIGS. 1A to 3, the fluidized bed boiler 1 includes four fuel supply ports 3 on one wall surface 21 of the combustion chamber 2, the same position in the vertical direction V, and the like in the horizontal direction H. The fuel chute paths 4 are connected to the respective fuel supply ports 3. In addition, one or more indoor injection sections 5 are provided below each of the four fuel supply ports 3, so that the fuel F can be distributed in a wider range and supplied throughout the fluidized bed. It becomes.

  According to the above configuration, the indoor injection unit 5 that injects the transfer gas G1 toward the combustion chamber 2 below the fuel supply port 3 in the wall surface 21 of the fluidized bed boiler 1 is provided. The fuel F supplied to the combustion chamber 2 from the fuel supply port 3 via 4 falls onto the transfer gas G1 injected from the indoor injection unit 5. At this time, the transport gas G1 is injected not horizontally or downwardly to boost the fall of the fuel F, but horizontally or upward from the horizontal in order to transport the fuel F far away. For this reason, the fuel F (recycled fuel) whose weight and size are not uniform is transported to the transfer gas G1 injected from the indoor injection unit 5 by a flight distance according to the size and weight of the fuel F, It falls to the fluidized bed L. As described above, the fuel F can be distributed and supplied in a wider range over the entire fluidized bed by the indoor injection unit 5, and the fuel can be more uniformly supplied to the entire fluidized bed. Thereby, more uniform combustion of the fuel F in the fluidized bed L can be realized, and generation of NOx and CO can be suppressed. In addition, when the fuel is uniformly supplied to the entire fluidized bed, for example, the installation of the indoor injection unit 5 is less expensive than the installation of a plurality of fuel chute paths 4 on the wall surface 21 of the combustion chamber 2. Manufacturing of the fluidized bed boiler 1 is possible because the scale of the fuel supply and transportation equipment such as the chute 4 and the conveyor connected to each fuel chute 4 and the distribution unit for distributing the fuel F to the fuel chute 4 can be reduced. And the cost required for operation (maintenance) can be greatly reduced.

  Moreover, in embodiment shown by FIG. 1A-FIG. 3, as above-mentioned, the gas G1 for conveyance is prepared by branching the gas conveyance pipe | tube 52 from the primary air supply pipe | tube 13 (refer FIG. 1A). . In some other embodiments, a part of the secondary air Gb is used as the transport gas G1 by branching the gas transport pipe 52 from the secondary air supply pipe 14 branched from the gas transport pipe 52. Also good. Thus, by using the fluidizing gas Ga or the secondary air Gb as the transport gas G1, the transport gas G1 can be prepared relatively easily.

  In some other embodiments, as shown in FIG. 1B, the transfer gas G <b> 1 is steam (self-steam) generated in the fluidized bed boiler 1. That is, the exhaust gas generated by the combustion of the fuel F in the combustion chamber 2 is heat-exchanged by the superheater provided in the fluidized bed boiler 1 to generate steam. In this manner, the steam generated by the fluidized bed boiler 1 itself is branched from the heat transfer tube group 12 and connected to the gas transport pipe 52, so that the self steam is used as the transport gas G1. In the embodiment shown in FIG. 1B, the gas conveyance pipe 52 is branched from the heat transfer pipe group 12 arranged at the rear stage of the combustion chamber 2. According to this configuration, the steam in the fluidized bed boiler 1 does not contribute to the combustion reaction in the combustion chamber 2, so that it does not burn and disappear during the transportation of the fuel F. For this reason, the fuel F can be distributed and supplied throughout the fluidized bed more reliably than when air is injected from the indoor injection unit 5.

  In the embodiment shown in FIGS. 1A to 3, the plurality of injection ports 5 a configuring the indoor injection unit 5 are arranged in a line in the horizontal direction H as shown in FIG. 2A. In some other embodiments, as shown in FIGS. 4A to 4B, the indoor injection sections 5 provided below the fuel supply port 3 on the wall surface 21 of the combustion chamber 2 are arranged in the horizontal direction H. The above injection port 5a may be a single stage and may be composed of a plurality of stages provided along the vertical direction V. 4A to 4B are schematic views showing a part of the wall surface 21 of the combustion chamber 2 in which the fuel supply port 3 according to the embodiment of the present invention is provided, and are an upper stage injection port group 54a and a lower stage injection port. The indoor injection part 5 which consists of a group 54b is shown. As shown in FIG. 4A, the indoor injection unit 5 includes an upper injection port group 54a composed of a plurality of injection ports 5a arranged on the wall surface 21 of the combustion chamber 2 adjacent to the horizontal direction H, and an upper injection port group 54a. And a lower injection port group 54b composed of a plurality of injection ports 5a arranged on the wall surface 21 of the combustion chamber 2 adjacent to the horizontal direction H. Alternatively, as illustrated in FIG. 4B, in the indoor injection unit 5, each of the upper injection port group 54 a and the lower injection port group 54 b may include one injection port 5 a. In addition, each of the one or more injection ports 5a constituting the upper injection port group 54a is configured to inject the carrier gas G1 at the first injection speed, and one or more of the one or more injection ports 5b constituting the lower injection port group 54b. Each of the injection ports 5a may be configured to inject the carrier gas G1 at a second injection speed that is an injection speed faster than the first injection speed.

  In the embodiment shown in FIG. 4A, each of the upper injection port group 54a and the lower injection port group 54b includes three injection ports 5a, and a total of six injection ports 5a are provided on the wall surface of the combustion chamber 2 as a whole. 21 is provided. Further, the upper injection port group 54a and the lower injection port group 54b are arranged so that the injection ports 5a belonging to each group are arranged in a straight line in the horizontal direction H at the same position in the vertical direction V. However, the arrangement of the upper jet group 54a and the lower jet group 54b is not limited to this embodiment. For example, the upper jet group 54a and the lower jet group 54b are different from each other in the jets 5a belonging to each group. , At the same position in the vertical direction V, they may not be arranged in a straight line in the horizontal direction H, and they may be shifted in the horizontal direction. Moreover, the indoor injection part 5 may consist of three or more steps.

  According to said structure, the injection speed (2nd injection speed) of the conveyance gas G1 from each injection port 5a which comprises the lower stage injection nozzle group 54b is from each injection hole 5a which comprises an upper stage injection nozzle group. This is faster than the jetting speed of the carrier gas (first jetting speed). As described above, by increasing the injection force of the lower stage from the upper stage in the vertical direction, the fuel can be distributed and supplied over the entire fluidized bed by the indoor injection unit 5. In some other embodiments, the first injection speed and the second injection speed may be the same, or the second injection speed may be slower than the first injection speed. The fuel F can be distributed and supplied throughout the fluidized bed by the transfer gas G1.

  Further, in some embodiments, as shown in FIG. 3, each of the plurality of injection ports 5 a constituting the indoor injection unit 5 described above is a carrier gas G <b> 1 injected from the adjacent injection ports 5 a. The ejection ranges R are configured to overlap each other on a horizontal plane. Normally, when the carrier gas G1 is injected in a predetermined injection direction from the injection port 5a, it spreads in the injection direction up and down, left and right, and proceeds in the injection direction while losing momentum according to the distance from the injection port 5a. . Here, the ejection range R indicates a range in which the momentum when ejected from the ejection port 5a has not completely disappeared. In the embodiment shown in FIGS. 1A to 3, as shown in FIG. 3, three injection ports 5 a are horizontally arranged on the wall surface 21 of the combustion chamber 2 by three indoor injection nozzles 51 (51 a to 51 c). Are arranged at equal intervals along H, and the ejection ranges R (Ra to Rc) of the adjacent indoor injection nozzles 51 (51a to 51c) (adjacent injection ports 5a) overlap at least partially. Yes. Specifically, the ejection range Ra of the first indoor injection nozzle 51a is the ejection range of the adjacent second indoor injection nozzle 51b at the right end in the ejection direction on the tip side away from the first indoor injection nozzle 51a (wall surface 21). It overlaps with the left end on the leading end side of Rb, and an overlapping portion Po is formed. Further, the ejection range Rb of the second indoor injection nozzle 51b overlaps with the left end on the distal end side of the ejection range Rc of the adjacent third indoor injection nozzle 51c at the right end in the ejection direction on the distal end side of the second indoor injection nozzle 51b. Thus, an overlapping portion Po is formed.

  On the contrary, a gap S is formed between the two adjacent indoor injection nozzles 51 (between 51a and 51b and 51b and 51c) on the wall surface 21 side with respect to the overlapping portion Po of the ejection range R. . The gap S becomes narrower as the overlap between the adjacent ejection ranges R becomes larger. As the gap S becomes narrower, the ratio of the fuel F that falls into the gap S naturally decreases, and the ratio of the fuel F that falls into the fluidized bed L as it is without being sprayed with the carrier gas G1 is reduced.

  According to said structure, the clearance gap S which arises between the gas G1 for conveyance ejected from each of the some indoor injection nozzle 51 can be reduced, and the gas G1 for conveyance from the indoor injection part 5 (injection port 5a). The fuel F jumping out from the fuel supply port 3 can be more reliably dropped into the jetting range R to be injected.

  Next, some other embodiments relating to the fuel chute path 4 in the configuration described above will be described. FIG. 5 is a schematic diagram showing a partial cross section of the fuel chute passage 4 connected to the combustion chamber 2 according to one embodiment of the present invention, and is an enlarged view of the vicinity of the connection portion 31. FIG. 6 is a schematic view of a part of the bottom surface 41 of the fuel chute passage 4 connected to the combustion chamber 2 according to one embodiment of the present invention as viewed from above. 7A to 7B are schematic views for explaining the protruding portion 7 formed in the fuel chute path 4 according to the embodiment of the present invention, and a partial cross section of the fuel chute path 4 is a combustion chamber. It is the figure seen from the front of 2. Moreover, FIG. 8 is a schematic diagram for demonstrating the dropping direction convex part 8 provided in the fuel chute path 4 which concerns on one Embodiment of this invention, (a) Front view, (b) Side view, c) A plan view of the bottom surface. All of the embodiments described below are configured to scatter (disperse) the fuel F in the fuel chute 4 (space).

  In some embodiments, as shown in FIG. 5, the gas for mixing is disposed on the bottom surface 41 of the fuel chute path 4 in a direction orthogonal to the bottom surface 41 of the fuel chute path 4 or downward below the orthogonal direction. A road injection port 6 for injecting G2 is formed. The mixing gas G2 is injected by the fuel F passing through the inside of the fuel chute 4 so that the fuel F lumps before the fuel F reaches the fuel supply port 3 and the inside of the fuel chute 4 The purpose of this is to make the fuel F dispersed (dispersed). When the mixing gas G2 is blown, the fuel F breaks down and scatters by colliding with the impact and other fuel F around the wall of the fuel chute path 4 and the surrounding area. As the mixing gas G2, for example, the fluidizing gas Ga, the secondary air Gb, the transporting gas G1, or the like may be used. The primary air supply pipe 13 that supplies the fluidizing gas Ga or the transporting gas G1 is used. The gas G2 for mixing may be supplied to the in-road injection port 6 by branching the pipe 63 from at least one of the gas transport pipe 52 to be supplied and the secondary air supply pipe 14 for supplying the secondary air Gb. .

  In the embodiment shown in FIG. 5, a nozzle (in-road injection nozzle 61) is provided on the bottom surface 41 of the fuel chute passage 4, and the mixing gas G <b> 2 is passed from the in-road injection nozzle 61 to the inside of the fuel chute passage 4. It is comprised so that it may inject. Further, as described above, the fuel chute path 4 is provided to be inclined obliquely upward at a predetermined installation angle θs with respect to the wall surface 21 of the combustion chamber 2, but in a side view as shown in FIG. The inner injection nozzle 61 is directed downward by a predetermined angle θ1 with respect to the direction of the normal N (orthogonal direction) of the bottom surface 41 of the fuel chute path 4 or the normal N. In this way, the momentum of the fuel F that falls on the fuel chute path 4 is such that the injection angle from the in-road injection port 6 cannot be directed upward with respect to the normal line N of the bottom surface 41 of the fuel chute path 4. It is configured to achieve its purpose without reducing.

  Further, in the embodiment shown in FIG. 5, as shown in FIG. 5, the plurality of road injection ports 6 (the road injection nozzles 61 in FIG. 5) are provided at the lower end of the bottom surface 41 of the cylindrical fuel chute path 4. In 41b, it arrange | positions at intervals along the longitudinal direction of the fuel chute path 4 (falling direction Fd of the fuel F). Further, each of the plurality of in-road injection ports 6 is configured to inject the mixing gas G2 at the same injection angle. However, the present invention is not limited to this embodiment, and in some other embodiments, the injection angles θ1 of each of the plurality of in-road injection ports 6 may not be the same. In addition, the number of the in-road injection ports 6 should just be one or more.

  Further, as shown in FIGS. 6A to 6B, at least one of the plurality of in-road injection ports 6 may be arranged in the short direction (width direction of the passage) of the fuel chute passage 4. good. Specifically, in FIG. 6A, the two in-road injection ports 6 are arranged side by side in the width direction with the center of the passage (the lower end 41b when the cross section is an arc). In FIG. 6B, two pairs of in-road injection ports 6 arranged in the width direction across the center of the passage are arranged in the longitudinal direction of the fuel chute passage 4, and the two pairs of in-road injections One in-road injection port 6 is disposed between the ports 6. In this case, the amount of the mixing gas G2 sprayed can be made different between the fuel F traveling in the center of the bottom surface 41 of the fuel chute path 4 and the fuel F traveling in a position away from the center in the width direction. Further, in FIG. 6C, the injection speed at the position in the width direction is adjusted in the same manner as in FIG. 6B by changing the shape of the one-way injection port 6 in the width direction of the passage. In FIG. 6C, the in-road injection port 6 has an opening that increases in the width direction from the center of the passage, and is configured to have the highest injection speed at the center. 6A to 6C as a set, these sets are spaced at equal intervals along the longitudinal direction of the fuel chute path 4 (the falling direction Fd of the fuel F). It may be provided open.

  According to the above configuration, the lump of the fuel F can be broken by the mixing gas G2 injected from the in-road injection port 6, and the fuel F can be dispersed (dispersed) inside the fuel chute path 4 (space). Can do. Further, the fuel F dispersed in the fuel chute passage 4 in this way is supplied into the combustion chamber 2 from the fuel supply port 3 and is transported by the transport gas G1, so that the fuel F over the entire fluidized bed. Can be distributed and supplied.

  In some other embodiments, the protrusion 7 is formed on the bottom surface 41 of the fuel chute path 4 as shown in FIGS. The protrusion 7 extends along a direction that intersects the falling direction Fd of the fuel F. In other words, the bottom surface 41 of the fuel chute path 4 extends so as to cross the falling direction Fd. In the embodiment shown in FIGS. 7A to 7B, the fuel F falls along the longitudinal direction of the cylindrical fuel chute path 4 (the fuel F fall direction Fd) toward the fuel supply port 3 along the fuel chute path 4. However, the bottom surface 41 of the fuel chute path 4 is formed as a protruding portion 7 provided along the longitudinal direction. For this reason, when the fuel F passes through the protruding portion 7 of the fuel chute path 4, the fuel F may change its direction due to the collision with the protruding portion 7 and may fall while bouncing the bottom surface 41 of the fuel chute path 4. Becomes higher. In the embodiment shown in FIG. 7A, the projecting portion 7 is formed by a plurality of convex and concave portions 7a (convex portions). In the embodiment shown in FIG. 7B, the projecting portion 7 is formed by a plurality of plate-like members 7b projecting from the bottom surface 41 of the fuel chute path 4 at intervals, and this plate-like member 7b is horizontal. Is formed on the bottom surface 41 of the fuel chute path 4 so as to face downward. Note that the number of the undulations 7 a and the plate-like members 7 b constituting the protruding portion 7 may be one or more, and the protruding portion 7 may be provided on at least a part of the bottom surface 41 of the fuel chute path 4. Accordingly, the lump of fuel F can be broken, and the fuel F can be dispersed (dispersed) inside the fuel chute path 4 (space). Further, the fuel dispersed in the fuel chute path 4 in this way is supplied into the combustion chamber 2 from the fuel supply port 3 and is transported by the transport gas G1, thereby dispersing the fuel F throughout the fluidized bed. Can be supplied.

  In some other embodiments, as shown in FIGS. 7A to 7B, the above-described in-road injection port 6 and the protruding portion 7 may be formed together on the bottom surface 41 of the fuel chute path 4. In the embodiment shown in FIGS. 7A to 7B, the protruding portion 7 is also provided at the position where the in-road injection port 6 is provided on the bottom surface 41 of the fuel chute path 4. In FIG. 7A, the road injection ports 6 are provided in a part of the plurality of valley portions (concave portions) of the plurality of undulations 7a forming the protrusions 7, but in all the valley portions. Each may be provided, or may be provided in at least a part of a plurality of peak portions of the protrusion 7. In FIG. 7B, the road injection port 6 is provided in a portion where the plate-like member 7b is not provided so as not to disturb the lump of the fuel F by the mixing gas G2 injected from the road injection port 6. Is provided. Further, the road injection port 6 may be provided in a portion where the projecting portion 7 is not provided on the bottom surface 41 of the fuel chute path 4. When provided at the same position, a plurality of in-road nozzles 6 are provided at predetermined intervals along the longitudinal direction with respect to the projecting portion 7 provided along the longitudinal direction on the bottom surface 41 of the fuel chute passage 4. It may be provided.

  In some other embodiments, as shown in FIG. 8, the bottom surface 41 of the fuel chute path 4 has a drop direction convex portion 8 extending over a predetermined range Ps along the drop direction Fd of the fuel F. It is formed. As shown in FIG. 8A, the drop direction convex portion 8 includes a top portion 81 located at the center of the fuel chute path 4 and a slope portion that slopes downward from the top portion 81 toward both sides in the cross-sectional shape. 82. In the embodiment shown in FIG. 8, the drop direction convex portion 8 is formed by a plate-like dispersion plate, and as shown in FIG. The two plate-like members are fixed at an angle so that the shape of the plate-like member is formed, or one plate-like member is bent. Further, the cylindrical fuel chute passage 4 has a circular cross-sectional shape, and the top 81 of the above-mentioned convex distribution plate is formed downward from the center of the cylinder in the vertical direction. 81 is connected to the bottom surface 41 of the fuel chute path 4. In FIG. 8A, the drop-direction convex portion 8 has a cross-sectional shape in a cross-sectional shape, but is not limited to this, and in other embodiments, the drop-direction convex portion 8 The cross-sectional shape may be an arc shape or may have a flat portion at the top portion 81. The drop direction convex portion 8 may be formed by processing so that the bottom surface 41 of the fuel chute path 4 is crushed toward the inside of the passage.

  Moreover, the drop direction convex part 8 is provided from the connection part 31 of the fuel chute path 4 and the fuel supply port 3 to a predetermined range Ps along the longitudinal direction of the fuel chute path 4 (FIG. 8B). c)). In the embodiment shown in FIG. 8, as shown in FIG. 8B, the fuel F falls in the falling direction Fd with reference to the bottom surface 41 of the fuel chute 4 over a predetermined range Ps. The height T of the drop direction convex portion 8 is gradually increased. In the embodiment shown in FIG. 8B, the drop direction convex portion 8 is between the connecting portion 31 between the fuel supply port 3 and the fuel chute path 4 and a position away from the connecting portion 31 by a predetermined range Ps. Is provided. Here, the height T of the above-mentioned drop direction convex portion 8 is based on the lower end 41b of the bottom surface 41 of the fuel chute path 4 at the lower end 41b of the bottom surface 41 of the fuel chute path 4 from the lower end 41b to the top 81. The distance is along the normal direction. In other words, as shown in FIG. 8B, the height T of the drop direction convex portion 8 is the fuel supply port from the most upstream connection position C with the bottom surface 41 of the fuel chute path 4 in a side view. 3 (connecting portion 31) gradually increases, and becomes the maximum at the end on the connecting portion 31 side. Similarly, the distance between the lower end 41b of the bottom surface 41 of the fuel chute path 4 and the connection position C between the inclined portion 82 and the bottom surface 41 of the fuel chute path 4 is also increased. As a result, the drop-direction convex portion 8 does not have a step generated at the end (the upstream end of the fuel chute path 4) that is separated from the fuel supply port 3 in the longitudinal direction of the fuel chute path 4 by a predetermined range Ps, or The fuel chute path 4 is smoothly connected to the bottom surface 41 of the fuel chute path 4 so as to prevent the fuel ch from being clogged with the fuel F. More specifically, as shown in FIG. 8C, as the fuel chute path 4 moves toward the fuel supply port 3, the connection position C between the arc-shaped bottom surface 41 of the fuel chute path 4 and the inclined portion 82 is , Away from the top 81 in the short direction of the fuel chute path 4 (the direction intersecting the falling direction Fd of the fuel F).

  Further, the surface (fuel passage surface) through which the fuel F of the inclined portion 82 of the drop direction convex portion 8 passes is formed in a planar shape or a curved surface. For example, in the fuel passage surface of the inclined portion 82, the fuel F If a partition wall is provided along the longitudinal direction of the fuel chute path 4 to guide the fall of the fuel, fuel F such as recycled fuel, which has a relatively large amount of moisture and is not uniform in shape, size, weight, etc., is located between the partition walls. There is a possibility of clogging. In this regard, in the present embodiment, the partition wall or the like is not formed on the inclined portion 82 of the drop direction convex portion 8 so that the fuel F is not clogged in the fuel chute path 4.

  According to the above configuration, the drop direction convex portion 8 has the top portion 81 and the inclined portion 82. Further, the fuel F that has traveled straight through the fuel chute path 4 receives a force in the lateral direction that is lateral to the falling direction Fd due to the inclination by passing through the inclined portion 82 of the falling direction convex portion 8. Thereby, when the fuel F jumps out from the fuel supply port 3 to the combustion chamber 2, the fuel F can be dispersed so as to spread left and right, and the fuel F can be better dispersed and supplied throughout the fluidized bed. it can. Further, the number of the fuel chute paths 4 can be further reduced by jumping out from the fuel supply port 3 so that the fuel F spreads left and right.

The present invention is not limited to the above-described embodiments, and includes forms obtained by modifying the above-described embodiments and forms obtained by appropriately combining these forms.
For example, although a bubble type fluidized bed boiler has been described as the fluidized bed boiler 1, the present invention is not limited to this and can be applied to, for example, a circulating fluidized bed boiler.
In the above description, the fuel chute path 4 has been described as having a cylindrical shape. However, the present invention is not limited to this, and the cross section of the fuel chute path 4 may be an ellipse or a polygon as long as it has a cavity inside. The shape may be another shape.

DESCRIPTION OF SYMBOLS 1 Fluidized bed boiler 12 Heat exchanger tube group 13 Primary air supply pipe 14 Secondary air supply pipe 15 Secondary air introduction nozzle 2 Combustion chamber 21 Wall surface 22 Bottom 23 Opposite wall surface 3 Fuel supply port 31 Connection part 4 Fuel chute path 41 Fuel chute Road bottom surface 41b Lower end 41e of fuel chute road bottom line 5 Indoor injection section 51 Indoor injection nozzle 51a First indoor injection nozzle 51b Second indoor injection nozzle 51c Third indoor injection nozzle 52 Gas transport pipe 54a Upper injection port group 54b Lower injection port group 55 Damper 56 Injection control device 6 In-road injection port 61 In-road injection nozzle 63 Pipe 7 Protruding portion 8 Falling direction convex portion 81 Top portion 82 Inclined portion C Connection position F between bottom surface and inclined portion of fuel chute path Fuel G1 Transport gas G2 Mixing gas Ga Fluidized gas (primary air)
Gb Secondary air L Fluidized bed N Normal line Po Overlapping portion Ps Predetermined range R Ejection range S Gap H Horizontal direction V Vertical direction Fd Falling direction θs Installation angle θ1 of fuel chute path Injection angle

Claims (10)

A combustion chamber that forms a fluidized bed by supplying fluidized gas;
A fuel supply port provided on a wall surface of the combustion chamber;
A fuel chute path connected to the fuel supply port for supplying fuel to the inside of the combustion chamber via the fuel supply port, wherein the gradient of the bottom surface of the fuel chute path is connected to the fuel supply port A fuel chute path that faces the combustion chamber toward the combustion chamber or downwards with respect to the horizontal in the section;
An indoor injection unit that is provided below the fuel supply port in the wall surface of the combustion chamber and injects a carrier gas toward the combustion chamber in the horizontal or horizontal direction upward. Fluidized bed boiler.   The fluidized bed boiler according to claim 1, wherein the transfer gas is steam generated in the fluidized bed boiler.   The fluidized bed boiler according to claim 1 or 2, wherein the indoor injection unit includes a plurality of injection ports arranged on the wall surface adjacent to each other in the horizontal direction. The indoor injection unit is
An upper jet group consisting of a plurality of jets arranged on the wall surface adjacent to each other in the horizontal direction;
A lower injection port group consisting of a plurality of injection ports arranged on the wall surface in the horizontal direction below the upper injection port group,
Each of the injection ports constituting the upper injection port group is configured to inject the carrier gas at a first injection speed,
Each of the injection ports constituting the lower injection port group is configured to inject the carrier gas at a second injection speed that is an injection speed faster than the first injection speed. The fluidized bed boiler according to claim 1 or 2.   5. Each of the plurality of injection ports is configured such that an ejection range of the carrier gas ejected from the ejection ports adjacent to each other overlaps each other on a horizontal plane. A fluidized bed boiler as described in 1.   The fluidized bed according to any one of claims 3 to 5, further comprising: an injection control device that periodically changes an injection speed of the transfer gas from each of the plurality of injection ports. boiler.   The bottom surface of the fuel chute path is formed with an in-channel injection port for injecting the mixing gas in a direction orthogonal to the bottom surface of the fuel chute path or in a direction lower than the orthogonal direction. The fluidized bed boiler according to any one of claims 1 to 6.   The fluidized bed boiler according to any one of claims 1 to 7, wherein a projecting portion is formed on a bottom surface of the fuel chute path. On the bottom surface of the fuel chute path, a drop direction convex portion is formed extending over a predetermined range along the fuel drop direction,
The fluidized bed boiler according to any one of claims 1 to 8, wherein the drop direction convex portion is configured to incline downward from the top toward both sides in a cross-sectional shape.   The drop direction convex part is configured so that the height of the drop direction convex part gradually increases downward in the fuel drop direction with reference to the bottom surface of the fuel chute path. Item 10. A fluidized bed boiler according to Item 9.

Images