JP3950428B2 - Fine fuel combustion burner and fine fuel combustion system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pulverized fuel combustion burner which uses a solid fuel such as coal, which is used for generating steam or the like in power generation or factory for example, as a fuel and a pulverized fuel combustion system including the same.
[0002]
[Prior art]
Conventionally, when burning solid fuel such as coal with a low volatile content or a high fuel ratio (fixed carbon content / volatile content), combustion is facilitated considering that volatile content is low and it is very difficult to burn. For this reason, a method is used in which solid fuel is pulverized and conveyed by air, and burned while the weight ratio between the amount of pulverized coal and the amount of air is kept low.
[0003]
An example of a pulverized fuel combustion burner that performs such combustion will be described with reference to FIGS.
The pulverized fuel combustion burner includes a burner wind box 13 connected to a duct through which combustion air circulates on the side opposite to the side facing the furnace 23, and the burner wind box 13 is divided into a plurality of partitions 24. Compartments 14, 15, 16 and so on. Each of the plurality of compartments will be described in more detail. A pipe 14a for supplying a concentrated coal mixture 19 obtained by pulverizing primary air and coal is inserted into one of the compartments. A deep burner nozzle 140 is swingably provided at the tip of 14a. Here, such a compartment is referred to as a dense coal compartment 14.
[0004]
A pipe 15a for supplying a fresh coal mixture 20 obtained by pulverizing primary air and coal is inserted into a compartment adjacent to the concentrated coal compartment 14 described above. A light burner nozzle 150 is swingably provided. Here, such a compartment is referred to as a light coal compartment 15.
[0005]
Next to these concentrated coal compartment 14 and light coal compartment 15, there are an auxiliary air compartment for sending auxiliary air for combustion toward the furnace 23, an oil compartment for sending oil toward the furnace 23, and the like. Yes, it is omitted in FIG. 4 and shown as a compartment 16 and its nozzle 160.
[0006]
One set of the combination of the dense coal compartment 14 and the light coal compartment 15 is defined as one stage of the pulverized fuel combustion burner, and a plurality of stages are installed in the burner wind box 13 according to required performance and the like. Moreover, the burner wind box 13 installed facing the furnace 23 is installed in all directions if the furnace 23 is rectangular, for example. In this case, a pulverized fuel supply circuit is constructed so that each stage of each burner wind box 13 is supplied with pulverized coal from a common pulverized coal machine (or coal pulverizer).
[0007]
Now, on the outside of the pulverized coal supply pipes 14a, 15a mounted in the state of being inserted into the dense coal compartment 14 and the light coal compartment 15, respectively, two ducts connected to the burner wind box 13 are connected. Secondary air 22a, 22b (secondary fluid) is circulating. And this secondary air 22a, 22b is sent to the furnace 23 through the flow path outside each burner nozzle 140,150 made into the box-type double tube structure according to the cross-sectional shape of each coal compartment 14,15. Is done. On the other hand, the rich coal mixture 19 and the light coal mixture 20 are sent to the furnace 23 through the flow passages inside the burner nozzles 140 and 150. Since the basic structure of the dark burner nozzle 140 and the light burner nozzle 150 is substantially the same as described above, the structure will be described in detail below using the dark burner nozzle 140 as including the light burner nozzle 150.
[0008]
FIG. 5 is a cross-sectional view illustrating the configuration of the dark burner nozzle 140.
As shown in the figure, the deep burner nozzle 140 is located on the furnace 23 side of the burner wind box 13 and can swing while being sandwiched in a vertical direction by a partition plate 24 that divides the burner wind box 13. Is installed.
[0009]
The rocking shaft 143 of the dark burner nozzle 140 supports the main body of the dark burner nozzle 140 so as to be rocked by being inserted into the side wall of the pipe 14a. Then, the rich burner nozzle 140 swings about the swing shaft 143, thereby sending the concentrated coal mixture 19 and the secondary air 22a flowing into the rich burner nozzle 140 in the vertical direction of the furnace 23. It is possible.
[0010]
The dark burner nozzle 140 mainly includes an inner cylinder wall 142 connected to the pipe 14a and an outer cylinder wall 141 located outside the inner cylinder wall 142. The outer cylindrical wall 141 and the inner cylindrical wall 142 have a shape that narrows from the rear end toward the front end on the furnace 23 side, and the front end is surrounded by the inner cylindrical wall 142. A coal mixture jet outlet 140a (primary side jet outlet) and a secondary air jet outlet 140b (secondary side jet outlet) formed between the outer cylinder wall 141 and the inner cylinder wall 142 are provided. In addition, the rear end portion is provided with an introduction port through which each of the above-described jet outlets 140a and 140b communicates, and is expanded more than the opening area of each of the jet outlets 140a and 140b in accordance with the opening shape of the dense coal compartment 14.
[0011]
Further, a seal plate 144 that swings around the swing shaft 143 described above is provided at a joint portion between the inner cylindrical wall 142 and the pipe 14a. The seal plate 144 has curved surfaces centering on the swing axis on the upper surface and the lower surface, and the outer peripheral surface 14b of the pipe 14a on which the seal plate 144 is arranged has a similar curved surface. Thus, it is possible to keep constant the gap generated in the joint portion following the swing of the dark burner nozzle 140. Further, a flange portion 144a is formed at the rear end portion of the seal plate 144 to be positioned with the dark burner nozzle 140 when swinging.
Reference numeral 146 indicates a current plate that rectifies the flow of the rich coal mixture 19.
[0012]
As a conventional technique for carrying out combustion with pulverized fuel using such a configuration, a structure for forming each compartment as described above by dividing a burner wind box into a plurality of parts by a partition plate has already been disclosed ( For example, see Patent Document 1.)
[0013]
In addition, in order to avoid a decrease in the flow rate in the burner nozzle when the burner nozzle is swung, a technology that suppresses the change in the flow path form by forming a convex protrusion in the flow path on the rear end side of the burner nozzle is preceded. It is disclosed as a technique (for example, see Patent Document 2).
[0014]
In addition, when the burner nozzle is swung, the rear end of the burner nozzle has a curved surface (generally a “scoop shape” so that the secondary air flowing through the compartment does not leak directly into the furnace. The structure formed is also disclosed (for example, refer to Patent Document 3).
[0015]
[Patent Document 1]
JP-A-7-158818 (paragraphs 16-18, FIG. 4)
[Patent Document 2]
JP-A-9-133322 (paragraphs 11-14, FIG. 1)
[Patent Document 3]
Japanese Patent Laid-Open No. 7-318049 (paragraphs 19-21, FIG. 1)
[0016]
[Problems to be solved by the invention]
In the pulverized fuel combustion system such as a boiler equipped with such a pulverized fuel combustion burner, the height dimension of the space portion in each compartment provided in the burner wind box partitioned by the partition plate is the nitrogen oxide ( NOx) and required performance such as heat load generated by the pulverized fuel combustion burner.
[0017]
Then, if the height dimension of each compartment is determined in accordance with the above requirements, this height dimension is expanded, and if it is attempted to determine the shape of the burner nozzle located at the opening on the furnace side in accordance with this, it is prescribed in advance. Further, it is necessary to widen the rear end portion in accordance with the size of the compartment with respect to the front end portion having each jet port. That is, it is necessary to make the shape greatly narrowed from the rear end portion to the front end portion of the burner nozzle.
[0018]
In this case, the secondary air that has flowed into the compartment passes through the flow path outside the inner cylinder wall that is installed as the structural member of the burner nozzle, but at the stage of flowing into the burner nozzle, it is almost the same as the flow velocity in the compartment. And much slower than the final rate. Accordingly, the flow rate of the secondary air is increased only by flowing through the burner nozzle having a narrow shape.
[0019]
This leads to a decrease in pressure at the rear end of the burner nozzle due to the slow flow rate of the secondary air, and depending on the conditions, it is equal to or lower than the pressure of the mixture of pulverized fuel that is the primary fluid in the vicinity. There is a case.
In such a state, as shown by an arrow L in FIG. 5, the concentrated coal mixture 19 as the primary fluid leaks out to the distribution side of the secondary air 22a from the gap at the joint portion between the burner nozzle and the primary fluid pipe. If the pressure of the secondary air 22a is significantly reduced with respect to the pressure of the rich coal mixture 19, the amount of leakage of the mixture as a fuel becomes great, which has a great influence on the combustion. It might be. In addition, burning of the burner and the wind box due to the combustion of coal inside the wind box may be caused, which may impede the operation of the burner.
[0020]
Further, as shown in FIG. 5, when the height dimension of the dark burner nozzle 140 is increased, this constricted shape is further promoted. Since it is necessary to secure a space that enables the rear end portion, the rear end portion is greatly separated from the partition plate 24. Therefore, a large gap is generated in the opening of the dense coal compartment 14, and the secondary air 22a often leaks directly into the furnace without passing through the burner nozzle 140. As a result, the secondary air side pressure in the vicinity of the gap between the rich burner nozzle 140 and the primary air fluid pipe is further remarkably reduced. As a result, the pressure difference between the primary side and the secondary side is reversed, and the rich coal mixture 19 Leakage will occur.
In addition, although the rich coal compartment 14 was demonstrated, it is the same also about the light coal compartment 15. FIG.
[0021]
Here, the conditions under which the rich coal mixture 19 leaks from the gap portion of the burner nozzle will be described.
The condition that the rich coal mixture 19 leaks is established when the pressure on the concentrated coal mixture 19 side, which is the primary fluid, is higher than that on the secondary air 22a side. There is a secondary air pressure at which the two pressures are reversed, that is, a secondary air flow rate. The air volume of the secondary air 22a is adjusted according to the required volume by a damper at the wind box inlet, and the air volume of the secondary air 22a decreases as this damper is throttled. In any coal burner with the above-mentioned structure, there is a point (limit) air volume at which both pressures are reversed if the air volume of the secondary air 22a is reduced in any burner, but as described above, the compartment height and nozzle shape If the air pressure is inappropriate, this limit airflow will be high and to prevent leakage, secondary air more than the primary airflow required for combustion is required, or depending on the conditions, leakage will be prevented even if the damper is fully opened. As a result, the burner is prone to leakage. In other words, if an attempt is made to set the secondary air flow rate necessary for combustion, leakage may occur.
Further, the condition that the rich coal mixture 19 leaks also changes when the rich burner nozzle 140 swings. Since the outer peripheral surface 14b of the end portion of the pipe 14a has a curved shape, the flow of the secondary air 22a forms a stagnation region near the inlet of the concentrated burner nozzle 140. At this time, for example, when the nozzle is directed upward, the gap portion of the rich burner nozzle 140 moves toward the inside of the furnace, and enters the stagnation region where it is difficult to receive the pressure of the secondary air 22a, and the critical air volume also increases.
[0022]
The present invention has been made in view of the above circumstances, and enhances the sealing performance at the joint between the burner nozzle that can be swung and the supply path of the primary fluid to prevent leakage of the primary fluid, and the outside of the burner nozzle. To provide a pulverized fuel combustion burner and a pulverized fuel combustion system including the same, which reduce and stabilize the amount of secondary fluid leaking directly from the furnace to the furnace to achieve stable combustion and improve combustion efficiency With the goal.
[0023]
[Means for Solving the Problems]
The present invention employs the following means in order to solve the above problems.
In the first aspect of the present invention, a primary fluid in which a primary fluid obtained by mixing finely pulverized solid fuel with air or other gas is injected into a furnace in a plurality of compartments in which a burner wind box is partitioned by a partition plate. In a pulverized fuel combustion burner comprising a jet nozzle and a swingable burner nozzle having a secondary jet nozzle that jets a secondary fluid that assists combustion supplied into the compartment around the primary fluid, The opening area in each cross section of the compartment orthogonal to the flow direction of the secondary fluid is gradually reduced toward the downstream side. The inner cylinder wall forming the partition wall between the primary fluid and the secondary fluid that circulates in the burner nozzle has a ridge formed at the rear end portion of the burner nozzle and protruding toward the secondary fluid flow side. Is provided It is characterized by that.
[0024]
According to such a configuration, the flow rate of the secondary fluid flowing in the compartment increases as it goes to the burner nozzle, and the rear end portion of the burner nozzle increases as the flow rate of the secondary fluid increases at the stage of flowing into the burner nozzle. The pressure of the secondary fluid at is increased. Further, the constricted shape of the burner nozzle is reduced.
Note that the shape in which the opening area in each cross section of the compartment gradually decreases as it goes downstream is not necessarily formed over the entire area in the flow direction of the secondary fluid, and may be a partially formed structure. Good.
[0025]
The invention according to claim 2 is the pulverized fuel combustion burner according to claim 1,
The partition plate is provided with a flow path reducing portion that gradually reduces the opening area in each cross section of the compartment orthogonal to the flow direction of the secondary fluid.
[0026]
According to such a configuration, the partition plate increases in thickness as it goes downstream in the flow direction of the secondary fluid, and the increased thickness portion functions as a flow path reduction portion. Then, the flow path area in the compartment through which the secondary fluid flows is gradually reduced by the flow path reducing portion as it goes to the burner nozzle. As a result, the flow rate and further the pressure of the secondary fluid are increased in the process of being guided to the flow path reduction portion, and the secondary fluid flows into the burner nozzle in a state where the pressure is increased. Further, the constricted shape of the burner nozzle is reduced in the same manner as in the above claims.
[0027]
The invention according to claim 3 is the pulverized fuel combustion burner according to claim 2,
At least a part of the flow path reduction portion is formed of a refractory material.
[0028]
According to such a configuration, the furnace side of the burner wind box in which the burner nozzle is located is substantially formed of the refractory material, and damage to the burner wind box due to heat load is avoided. Note that the refractory material may be filled in a frame that forms the flow path reduction portion, or a member made of the same material that is molded in advance may be installed on the partition plate.
[0029]
The invention according to claim 4 is the pulverized fuel combustion burner according to any one of claims 1 to 3,
A part of the outer peripheral surface of the rear end portion of the burner nozzle is formed as a part of a cylindrical surface with the swing axis of the burner nozzle as an axis.
[0030]
According to such a configuration, the gap between the outer peripheral surface of the rear end portion of the burner nozzle facing the partition plate and the partition plate facing the burner nozzle is kept constant regardless of the swing of the burner nozzle. And by minimizing this gap, no matter what position the burner nozzle swings, the secondary fluid flowing in the compartment will not leak directly into the furnace without going through the burner nozzle, and almost the entire amount will be It will flow into the burner nozzle.
[0031]
the above In the pulverized fuel combustion burner, the inner cylinder wall forming the partition wall between the primary fluid and the secondary fluid that circulates in the burner nozzle is positioned at the rear end portion of the burner nozzle and protrudes toward the secondary fluid circulation side. A formed ridge is provided.
[0032]
According to such a configuration, a part of the secondary fluid that circulates outside the inner cylinder wall collides with a ridge that is located at the rear end of the inner cylinder wall and protrudes toward the secondary fluid circulation side. Thus, the pressure increases in a region upstream of the soot. That is, by providing a soot at the joint between the burner nozzle and the primary fluid supply path, the pressure in the vicinity of the soot can be efficiently kept high, and even when the secondary fluid flow rate is lower, the secondary fluid The reversal of the side pressure and the primary fluid side pressure does not occur, that is, the primary fluid does not leak to the secondary fluid circulation side outside the inner cylindrical wall.
[0033]
Claim 5 The pulverized fuel combustion system according to claim 1 is a furnace installed in the vicinity of an object to be heated, and jetted and combusted fuel atomized toward the furnace. 4 A pulverized fuel combustion burner according to any one of the above, a pulverized fuel supply circuit for supplying a primary fluid containing pulverized fuel to the pulverized fuel combustion burner, and a secondary fluid for supplying a secondary fluid to the pulverized fuel combustion burner. And a secondary fluid supply circuit.
[0034]
According to such a configuration, stable combustion by the pulverized fuel combustion burner is performed on the furnace, and the object to be heated is efficiently heated and converted to, for example, power.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a partial cross-sectional view illustrating a partial configuration of a pulverized fuel combustion burner in the present embodiment. FIG. 2 is a cross-sectional view of a main part of the pulverized fuel combustion burner showing an enlarged portion indicated by the symbol A in FIG. FIG. 3 is a plan sectional view of the pulverized fuel combustion burner in the BB section of FIG.
[0036]
In addition, the structure demonstrated below shall be based on the structure of the concentrated coal compartment 14 demonstrated by the prior art, and the description shall be partially omitted including the light coal compartment 15. FIG. In addition, the code | symbol 40 shown by FIG. 3 is a rocking device which rocks the burner nozzle 30. FIG.
In addition, the pulverized fuel combustion burner of this embodiment is provided in a pulverized fuel combustion system including a pulverized fuel supply circuit that generates pulverized coal and mixes with air, and a secondary air supply circuit using a duct. The pulverized fuel combustion system according to the present invention is realized.
[0037]
The partition plate denoted by reference numeral 50 is composed of a plurality of members, and a partition plate main member 51 disposed at a predetermined position in the height direction similar to the conventional one according to the required performance of the thermal load, and the partition. It consists of the 1st partition plate auxiliary material 52 and the 2nd partition plate auxiliary material 53 which are installed on the plate main material 51, and form a part of flow-path reduction part 50a.
[0038]
The first partition plate auxiliary material 52 and the second partition plate auxiliary material 53 are connected in the longitudinal direction of the compartment 14 (left and right direction on the paper surface), and are inclined to the upstream side in the circulation of the secondary air 22a. A first partition plate auxiliary material 52 having a surface 52 a is arranged, and a second partition plate auxiliary material 53 reaching the furnace 23 side is arranged downstream of the first partition plate auxiliary material 52. The second partition plate auxiliary material 53 located on the furnace 23 side is made of a refractory material such as alumina, and the durability of the burner wind box 13 is made almost using the wall surface of the burner wind box 13 facing the furnace 23 as a refractory material. Improves sex.
[0039]
These first and second partition plate auxiliary materials 52 and 53 form a flow path reducing portion 50 a by being pushed out toward the internal space of the compartment 14, and the flow velocity of the secondary air 22 a flowing through the compartment 14. It plays a role to raise.
That is, contrary to the fact that the thickness of the partition plate 50 is gradually increased by the inclined surface 52a of the first partition plate auxiliary material 52, the flow passage area of the secondary air 22a is changed from the upstream side to the downstream side by reference numerals S1 and S2. As shown in the figure, when the flow path area is gradually reduced, the flow velocity of the secondary air 22a is increased, and the pressure when flowing into the burner nozzle 30 is also increased. Become.
[0040]
In the present embodiment, the region in which the thickness of the partition plate 50 changes is implemented only for a part in the longitudinal direction of the compartment 14 as shown in the figure, and flows to the upper or lower end of the burner nozzle 30 in the horizontal position. It becomes horizontal when the projecting height of the road reducing portion 50a has reached.
Of course, the shape of the flow path reducing portion 50a is not limited to this, and may be any shape as long as the flow path area is gradually reduced.
[0041]
Next, the configuration of the burner nozzle 30 will be described.
As shown in the figure, the burner nozzle 30 is positioned on the furnace 23 side of the burner wind box 13 and sandwiched in the vertical direction by a partition plate 50 having a flow path reducing portion 50a that divides the burner wind box 13. It is installed so that it can swing. For this reason, the shape of each burner nozzle described in the prior art is slightly different, and the difference is that the shape of the tip is the same, whereas the opening area on the furnace 23 side of the compartment 14 is the rear end. Since the size is reduced by the reduction, the shape narrowed from the rear end portion toward the front end portion is reduced.
[0042]
The swing shaft 33 of the burner nozzle 30 supports the burner nozzle 30 so as to be swingable by being inserted into the side wall of the air-fuel mixture supply pipe 14a that is the primary fluid. The burner nozzle 30 swings about the swing shaft 33, whereby the mixture 19 (primary fluid) of pulverized coal and air and the secondary air 22a (secondary fluid) flowing into the burner nozzle 30 are heated in the furnace. 23 can be ejected in the vertical direction.
[0043]
The burner nozzle 30 has a box-shaped double pipe structure as described in the prior art, and this structure has an outer cylindrical wall 31 forming an external shape and an inner cylindrical wall arranged on the inner side. 32 constitutes the main structure.
[0044]
The inner cylindrical wall 32 is connected to the end of the mixture supply pipe 14a at the rear end, and the outer cylindrical wall 31 is connected to the opening of the compartment 14 whose opening area is reduced at the rear end. Facing. Accordingly, the air-fuel mixture 19 that is the primary fluid flows through the space surrounded by the inner cylindrical wall 32, and the air-fuel mixture 19 is ejected from the primary-side outlet 30a provided on the furnace 23 side to the furnace 23. Will be. In addition, secondary air 22a that constitutes a secondary fluid that circulates in the compartment 14 circulates in a space formed between the inner cylindrical wall 32 and the outer cylindrical wall 31, and the auxiliary fluid 22a is supplied to the furnace. It is ejected from the secondary side ejection port 30b provided on the 23rd side so as to cover the periphery of the air-fuel mixture 19.
[0045]
Furthermore, the rear end portion of the inner cylindrical wall 32 is provided with a flange 32a provided so as to protrude to the flow side of the secondary air 22a. The flange 32a is provided on the upper surface and the lower surface side of the inner cylinder wall 32, and is also provided on the side surface as shown in FIG. 3, and is formed on the entire circumference of the rear end portion of the inner cylinder wall 32 as a whole. .
[0046]
As shown in FIG. 2, the height h1 of the flange 32a is set to about 35% of the height h2 of the flow path through which the secondary air 22a flows, and a part of the auxiliary fluid 22a flowing therethrough It plays the role of increasing the pressure by blocking. That is, when the secondary air 22a whose flow velocity has been increased flows into the burner nozzle 30, a part of the secondary air 22a collides with the flange 32a, and the vortex of the secondary air 22a is generated upstream of the flange 32a. Rises.
[0047]
This leads to an operation in which the air-fuel mixture 19 that leaks from the gap between the seal plate 144 and the burner nozzle 30 does not flow out. This is because the pressure state in the vicinity of the gap is increased by the installation of the flange 32a, and even when the flow rate of the secondary air 22a is smaller, the secondary air 22a side pressure and the air-fuel mixture 19 side pressure are not reversed, and the air-fuel mixture 19 Does not leak to the secondary air 22a side.
[0048]
The height h1 of the flange 32a is set to about 35% of the flow path height h2 in the vicinity thereof, so that the flow of the auxiliary fluid 22a flowing into the burner nozzle 30 is not hindered, and the air-fuel mixture It leads to the minimum pressure increase necessary to avoid 19 leaks.
However, the height h1 of the eaves 32a described here is not necessarily set to about 35% of the flow path height h2, and the flow path opening area in the vicinity of the eaves 32a is not limited to the opening of the secondary side outlet 30b. If the pressure difference between the air-fuel mixture 19 and the secondary air 22a is greater than or equal to a predetermined value by the action of the flow path reducing portion 50a or the like while taking a larger area, it may be set to about 5%.
[0049]
On the other hand, a scoop 31 a forming a part of a cylindrical surface with the swing shaft 33 as an axis is formed on the upper surface and the lower surface forming a part of the outer peripheral surface at the rear end portion of the outer cylindrical wall 31. The outer radius of the curved scoop 31a is substantially the same as the length of the perpendicular dropped from the swing axis to the plane of the flow path reducing portion 50a. To be precise, the radius with respect to the partition plate 50 when the burner nozzle 30 swings. To avoid interference, the radius of the scoop 31a is set to be smaller than the length of the perpendicular.
[0050]
As a result, the gap between the outer peripheral surface of the rear end portion of the burner nozzle 30 that faces the flow path reducing portion 50a that forms part of the partition plate 50 and the plane of the flow path reducing portion 50a is independent of the oscillation of the burner nozzle 30. Since the gap is set to a minimum, the secondary air 22a flowing through the compartment 14 is hardly leaked directly into the furnace 23 regardless of the position of the burner nozzle 30. It is.
As a result, almost the entire amount of the secondary air 22a flowing in the compartment 14 flows into the burner nozzle 30 and is blown out from the secondary side outlet 30b to the furnace 23 for combustion. Further, this prevents the secondary air side pressure in the vicinity of the gap between the burner nozzle and the primary air fluid pipe from being lowered when the burner nozzle is swung, thereby preventing reversal of the differential pressure between the primary side and the secondary side.
[0051]
According to the pulverized fuel combustion burner in the present embodiment described above and the pulverized fuel combustion system such as a boiler equipped with the burner, the following effects can be obtained.
By providing the flow path reducing portion 50a in the compartment 14, the flow rate of the secondary air 22a flowing into the burner nozzle 30 is increased, and the pressure state is increased more than the pressure of the air-fuel mixture 19 with a smaller flow rate of the secondary air 22a. Therefore, by using this differential pressure, the sealing performance at the rear end of the burner nozzle 30 can be enhanced to prevent the air-fuel mixture 19 from leaking, and the flow rate of the secondary air 22a can be set to be optimal for combustion.
[0052]
Further, the constricted shape of the burner nozzle 30 can be reduced, and the occurrence of a gap in the opening of the compartment 14 due to the swinging is suppressed, and the leakage of the secondary air 22a is reduced to stabilize the combustion. be able to. Further, by using a refractory material for the flow path reducing portion 50a, it is possible to realize a highly durable pulverized fuel combustion burner capable of avoiding burning of the burner wind box 13 and the like.
[0053]
In addition, by providing the flange 32a at the rear end portion of the inner cylindrical wall 32 of the burner nozzle 30, the pressure state at the rear end portion of the burner nozzle can be more reliably increased, and the flow rate of the secondary air 22a is small. However, the differential pressure can be reliably guided to prevent the air-fuel mixture 19 from leaking.
Further, by forming the scoop 31a on a part of the outer peripheral surface of the rear end portion of the burner nozzle 30, the secondary air 22a flowing in the compartment 14 can be quantitatively introduced into the burner nozzle 30 at any swing angle. . This ensures a reduction in the leakage of the secondary air 22a as well as a reduction in the constricted shape of the burner nozzle 30.
[0054]
And by each of these effects, the air-fuel mixture 19 of pulverized coal, which is the primary fluid, can be stably ejected to the furnace 23 in a specified amount without being influenced by the swinging of the burner nozzle 30. The secondary air 22a as a fluid can be ejected around the air-fuel mixture 19 in a stable and specified amount. Therefore, it becomes possible to perform combustion of the pulverized fuel by the pulverized fuel combustion burner stably and with high efficiency.
And according to the pulverized fuel combustion system provided with such a pulverized fuel combustion burner, efficient heating can be performed by performing stable combustion, and highly efficient operation can be performed.
[0055]
【The invention's effect】
The pulverized fuel combustion burner of the present invention described above and the pulverized fuel combustion system including the same have the following effects.
According to the first aspect of the present invention, when the pressure state of the secondary fluid flowing around the burner nozzle is increased, the sealing performance is improved, and the flow rate of the secondary fluid is low, including the condition that the burner nozzle is swung. However, the primary fluid does not leak to the secondary fluid side in the compartment. As a result, the primary fluid can be ejected to the furnace in a stable and specified amount without being influenced by the swinging of the burner nozzle, and the secondary fluid is ejected around the primary fluid in a stable state. Can do. Therefore, it becomes possible to perform combustion of the pulverized fuel by the pulverized fuel combustion burner stably and with high efficiency. In addition, it is possible to set a burner nozzle having a shape suitable for the required capacity without being affected by the size of the compartment, reducing the constriction shape and preventing leakage of secondary fluid from the outside of the burner nozzle during oscillation. Can be reduced.
[0056]
According to invention of Claim 2, the opening area in each cross section of the compartment orthogonal to the flow direction of a secondary fluid can be gradually reduced by the flow-path reduction part which makes a part of partition plate, Claim 1 The same effect as can be accurately obtained. Moreover, the space | interval of adjacent burner nozzles can also be prescribed | regulated suitably according to a flow path reduction part, and the freedom degree of design can be raised. Further, the constricted shape of the burner nozzle can be reduced, and the leakage of the secondary fluid from the outside of the burner nozzle during swinging can be reduced.
[0057]
According to the third aspect of the present invention, since the flow path reducing portion located on the furnace side is formed using the refractory material, the fire resistance of the burner wind box is improved, and the burner wind box is prevented from being burned out. Thus, the durability of the pulverized fuel combustion burner can be improved.
[0058]
According to the invention described in claim 4, since the outer peripheral surface of the rear end portion of the burner nozzle is formed as a part of a cylindrical surface with the swing axis of the burner nozzle as an axis, the secondary fluid flowing through the compartment is the burner nozzle. The entire amount flows into the burner nozzle in the entire swing range. As a result, a predetermined amount of secondary fluid can always be supplied to the primary fluid ejected from the primary side injection port, and the second fluid in the vicinity of the gap between the burner nozzle and the primary air fluid pipe when the burner nozzle swings. The primary air side pressure does not decrease, and the reverse of the differential pressure between the primary side and the secondary side, that is, leakage of the primary air fluid to the secondary air side can be prevented. As a result, the combustion of the pulverized fuel by the pulverized fuel combustion burner can be performed stably and efficiently without being influenced by the position of the burner nozzle.
[0059]
According to the fifth aspect of the present invention, even if the flow rate of the secondary fluid is lowered, a sufficient differential pressure between the primary fluid and the secondary fluid can be secured, so that the pulverized fuel combustion burner can be operated with a small flow rate. The primary fluid flowing into the burner nozzle does not leak to the secondary fluid side at the rear end of the burner nozzle, and the primary fluid is ejected from the primary side outlet in a stable and prescribed amount without causing unexpected combustion. be able to. Further, the secondary fluid can be ejected from the secondary-side jet outlet in a stable state without being influenced by the intrusion of the primary fluid.
[0060]
According to the sixth aspect of the present invention, since efficient heating is possible by stable combustion by the pulverized fuel combustion burner, it is possible to realize a pulverized fuel combustion system that enables highly efficient operation.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view illustrating a partial configuration of a pulverized fuel combustion burner according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a main part of a pulverized fuel combustion burner in which a portion indicated by reference sign A in FIG.
FIG. 3 is a plan sectional view of the pulverized fuel combustion burner in the BB section of FIG. 1;
FIG. 4 is a sectional view of a burner wind box for explaining the configuration of a conventional pulverized fuel combustion burner.
FIG. 5 is a partial cross-sectional view illustrating a partial configuration of a conventional pulverized fuel combustion burner.
[Explanation of symbols]
14 compartments
14a Pipe for supplying air-fuel mixture (primary fluid supply path)
19 Air-fuel mixture (primary fluid)
22a Secondary air (secondary fluid)
30 Burner nozzle
30a Primary outlet
30b Secondary outlet
31 outer cylinder wall
31a scoop
32 Inner cylinder wall
32a 鍔
33 Oscillating shaft
50 divider
50a Flow path reduction part

Claims (5)

In a plurality of compartments in which a burner-like box is divided by a partition plate, a primary side jet outlet for jetting a primary fluid mixed with finely pulverized solid fuel and air or other gas into a furnace, and in the compartment In a pulverized fuel combustion burner having a oscillating burner nozzle having a secondary-side jet outlet for jetting a supplied secondary fluid for assisting combustion around the primary fluid, orthogonal to the flow direction of the secondary fluid The opening area in each cross section of the compartment is gradually reduced toward the downstream side, and the inner cylinder wall forming the partition wall between the primary fluid and the secondary fluid flowing through the burner nozzle has a rear end of the burner nozzle. A pulverized fuel combustion burner, characterized by being provided with a soot that is located at a portion and protrudes toward the flow side of the secondary fluid .   2. The pulverized fuel combustion burner according to claim 1, wherein the partition plate is provided with a flow path reducing portion that gradually reduces an opening area in each cross section of the compartment orthogonal to the flow direction of the secondary fluid. Features a pulverized fuel combustion burner.   The pulverized fuel combustion burner according to claim 2, wherein at least a part of the flow path reducing portion is formed of a refractory material.   4. The pulverized fuel combustion burner according to claim 1, wherein a part of the outer peripheral surface of the rear end portion of the burner nozzle is a part of a cylindrical surface about the swing axis of the burner nozzle. A pulverized fuel combustion burner characterized by being formed. A furnace installed in the vicinity of an object to be heated, and a pulverized fuel combustion burner according to any one of claims 1 to 4 , wherein the pulverized fuel directed toward the furnace is ejected and burned. A fine powder comprising a pulverized fuel supply circuit for supplying a primary fluid containing pulverized fuel to a pulverized fuel combustion burner, and a secondary fluid supply circuit for supplying a secondary fluid to the pulverized fuel combustion burner. Fuel combustion system.

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