KR20210113370A - solid fuel burner - Google Patents

Abstract

The venturi 33 shrinks the flow path 24 of the mixed fluid in the fuel nozzle 21 toward the center of the flow path cross section, and a velocity component in a direction away from the center of the fuel nozzle 21 is applied to the mixed fluid. A fuel concentrator 34 to be used, and a flow path partition member 36 for partitioning the flow path of the fuel nozzle 21 to the inside and outside, to give a swirl to the mixed fluid, and to the inside of the fuel nozzle 21 . With the plurality of blades 34c and 34d that are not completely fixed, even when solid fuel particles obtained by pulverizing biomass fuel are used, the fuel concentration effect can be ensured.

Description

solid fuel burner

The present invention relates to a solid fuel burner for conveying and burning a solid fuel, and more particularly, to a solid fuel burner suitable for fuel particles having a large particle size such as biomass particles.

In order to improve the ignition property of the solid fuel burner used for boilers, such as a thermal power plant, and to raise flame stability, raising a fuel concentration locally is performed.

In general, in a solid fuel burner using pulverized coal or the like as a fuel, a velocity component is applied to a mixed fluid of a fuel carrier gas and fuel particles from the inside of the fuel nozzle toward the inner wall surface of the nozzle, and the fuel particles are concentrated along the inner wall surface of the nozzle. There are many things that provide such a fuel concentrator.

For example, in Patent Document 1 (Japanese Patent No. 6231047 Specification: JP 6231047 B2), in the central portion of the fuel nozzle (sometimes referred to as a primary air nozzle) 9, the first turning is given to the mixed fluid. The technique of providing the machine 6 and the 2nd turning machine 7 which gives the turning in the reverse direction of the 1st turning machine 6 is described. In the technique described in Patent Document 1, a strong swirl is applied to the mixed fluid by the first swirler 6 to move the solid fuel particles toward the outer peripheral side of the fuel nozzle (along the inner wall surface of the fuel nozzle).

Then, the rotation of the mixed fluid is weakened by giving the rotation in the opposite direction to the first swinging device 6 in the second swinging machine 7 .

Therefore, the state in which the solid fuel particles are concentrated is maintained around the burner opening and the flame retarder 10 installed at the tip of the fuel nozzle, and the ignitability of the fuel particles is increased even at a low load with a low fuel concentration supplied to the burner, Flame stability is improved.

At the same time, since the mixed fluid with reduced rotation is ejected from the opening, the mixed fluid does not spread excessively in the furnace, and the mixture with the combustion gas (air) such as secondary air and tertiary air is smoothed and nitrogen oxides (NOx) ) to suppress the production.

Specification of Japanese Patent No. 6231047 (identification number "0004", "0048" to "0061", FIGS. 1 to 3, and FIG. 21) Specification of Japanese Patent No. 4919844 (identification numbers "0021" to "0023") Japanese Patent Laid-Open No. 2010-242999 (identification number "0033")

As a fuel for mixing in a thermal power generation coal (pulverized coal) combustion boiler, what made a wood-based raw material into pellets is widely used. Here, the pellet is not used as it is, but as a pulverizing device, fuel particles obtained by pulverizing and classifying in an improved mill (pulverizer/classifier) based on a coal mill (pulverizer) as a carrier gas as a solid fuel It is conveyed to a burner, and the mixed fluid of fuel particle and carrier gas is supplied to a burner, and it burns like pulverized coal.

However, biomass fuel is difficult to pulverize compared to coal, so the mill's pulverization power is large (it is made from wood chips with a particle diameter of 50 mm to the same particle size as coal, but approximately 10 times the power of coal is required). It is difficult to atomize to the same level as pulverized coal. Moreover, when biomass fuel is pulverized, the possibility of rapid combustion will increase, and the prevention countermeasure will also be needed. Therefore, biomass fuel is discharged from wheat in a state of considerably coarser particles compared to coal (see Patent Document 2: Japanese Patent No. 4919844, Japanese Patent Document 3: Japanese Patent Application Laid-Open No. 2010-242999, etc.).

As a result, coarse-grained biomass fuel has a lower ignitability than pulverized coal.

On the other hand, in the case of using a fuel with low ignition property, if the flow rate of the mixed fluid is lowered, ignition tends to occur. It is not realistic, as it is likely to result in a stay in

Therefore, it is necessary to keep the flow rate of the mixed fluid (fuel carrier gas) high until just before combustion with the burner.

For this reason, the flow passage cross-sectional area of the fuel nozzle is made smaller on the upstream side, that is, on the fuel conveying system (connection with fuel conveying pipe) side connected from the crusher, and larger than the upstream side on the downstream side, that is, the furnace opening side, thereby reducing the flow rate. , it may be considered to improve ignition properties.

Here, Patent Document 3 is a mechanism for concentrating the fuel of the mixed fluid, including a venturi and a fuel concentrator providing a velocity component in a direction away from the center of the fuel nozzle, and the inner diameter of the furnace side opening of the fuel nozzle This discloses a solid fuel burner formed larger than the inner diameter of the upstream end of the venturi. If it is such a structure, since the flow rate can be reduced just before burning a fuel particle with a burner, maintaining the flow rate of a mixed fluid high within a conveyance system, the improvement of ignition property is achieved.

On the other hand, the curved pipe part is provided in the fuel nozzle upstream side of the solid fuel burner described in patent document 3, and the connection part with the fuel conveyance piping from a mill to a burner. The mixed fluid flows through a flow path communicating from the fuel conveying pipe through the curved pipe to the straight pipe of the fuel nozzle.

As a result of analysis by the inventors' simulation model, etc., in such a configuration, the high-speed fluid passing through the curved pipe part easily flows downward to be reflected after impacting the upper surface. When a velocity component in a direction away from the center of the fuel nozzle is given by the fuel concentrator of It turns out that this is prone to being excessively slow. And, if the flow rate is excessively slow, the fuel tends to be deflected toward the central portion in the radial direction by its own weight, and a region with a low fuel concentration is generated in the vicinity of the outlet of the fuel nozzle on the upper radial outer side. , it was found that there is a possibility that the fuel enrichment effect may be lowered.

In the solid fuel burner, the present invention is a fuel by a fuel concentrator provided in the fuel nozzle, even when a fuel with coarse particles such as obtained by pulverizing biomass fuel (such as a wood-based raw material into pellets) in a mill is used. It is a technical task to secure the concentration effect of

In order to solve the above technical problem,

The solid fuel burner of the invention according to claim 1,

A fuel nozzle through which a mixed fluid of a solid fuel and its carrier gas flows and is opened toward the furnace;

a combustion gas nozzle disposed on the outer periphery of the fuel nozzle and ejecting combustion gas;

A solid fuel burner having a fuel concentrator provided on the central side of the fuel nozzle and providing a velocity component in a direction away from the center of the fuel nozzle to the mixed fluid,

The fuel concentrator has a plurality of blades for imparting rotation to the mixed fluid, and each blade is spaced apart from the inner surface of the fuel nozzle without being completely fixed to the inside of the fuel nozzle. A first swirler disposed on the upstream side of the flow direction, and a second swirler disposed on a downstream side in the flow direction of the mixed fluid with respect to the first swirler, wherein the turning direction of the plurality of blades is opposite to the first swirler have a turntable,

It is characterized in that a flow path partition member is provided on the downstream side in the flow direction of the mixed fluid with respect to the second swirler for partitioning the flow path of the fuel nozzle to the inside and the outside in the flow path cross section.

The invention according to claim 2 is the solid fuel burner according to claim 1,

It is characterized in that the outer diameters of the first and second turning machines are less than or equal to the inner diameter of the upstream end of the flow path partition member.

The invention according to claim 3 is the solid fuel burner according to claim 1,

The flow path partition member is characterized in that the inner diameter of the upstream end is larger than the inner diameter of the downstream end.

The invention according to claim 4 is the solid fuel burner according to claim 3,

An outer diameter of the second revolving machine is smaller than an inner diameter of an upstream end of the flow path partition member and larger than an inner diameter of a downstream end of the flow path partition member.

The solid fuel burner of the invention according to claim 5,

A fuel nozzle through which a mixed fluid of the solid fuel and its carrier gas flows and opens toward the furnace;

a combustion gas nozzle disposed on the outer periphery of the fuel nozzle and ejecting combustion gas;

In the solid fuel burner provided on the central side of the fuel nozzle, a fuel concentrator for applying a velocity component in a direction away from the center of the fuel nozzle to the mixed fluid,

The fuel concentrator has a plurality of blades for imparting rotation to the mixed fluid, and each blade is spaced apart from the inner surface of the fuel nozzle without being completely fixed to the inside of the fuel nozzle. A first swirler disposed on the upstream side of the flow direction, and a second swirler disposed on a downstream side in the flow direction of the mixed fluid with respect to the first swirler, wherein the turning direction of the plurality of blades is opposite to the first swirler have a turntable,

The flow path of the fuel nozzle has an inner diameter of the same or monotonically increasing upstream side on the upstream side of the first swirler, and a pipe expansion part communicating with the downstream side of the upstream part and gradually expanding the inside diameter, and the pipe expansion part It is characterized in that it has a downstream part communicating with the downstream side and having a constant inner diameter.

The invention according to claim 6 is the solid fuel burner according to claim 5,

At least a part of the first swirler is located in the range of the upstream part of the fuel nozzle flow path,

At least a part of the second swirler is located in a range downstream of the fuel nozzle passage.

The invention according to claim 7 is the solid fuel burner according to claim 6,

A flow path partition member for partitioning a flow path of the fuel nozzle into an inner side and an outer side in a flow passage cross section is provided in a range downstream of the fuel nozzle flow path.

The invention according to claim 8 is the solid fuel burner according to claim 7,

The flow path partition member has a shape in which the inner diameter of the upstream end is larger than the inner diameter of the downstream end,

An outer diameter of the second revolving machine is smaller than an inner diameter of an upstream end of the flow path dividing member and larger than an inner diameter of a downstream end of the flow path dividing member.

The invention according to claim 9 is the solid fuel burner according to any one of claims 1 to 8,

It is characterized in that the outer diameter of each of the swirling machines is less than the inner diameter of the upstream portion of the fuel nozzle passage.

According to the invention described in claim 1, by having a fuel concentrator having two swirlers and a flow path partition member, in a solid fuel burner, biomass fuel (such as wood-based material pellets) is pulverized in a mill, Even in the case of using a fuel with coarse particles as obtained, the fuel concentration effect by the fuel concentrator provided in the fuel nozzle is ensured, and ignition properties and flame stability can be improved.

According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, compared to the case where the outer diameter of the blade of each vortex is larger than the inner diameter of the upstream end of the flow path partition member, the fuel is applied closer to the outer periphery. Since the carrier gas can be dispersed to the inner periphery as it is, the effect of concentrating the fuel on the outer periphery can be improved. Moreover, according to the invention of Claim 2, the flow velocity of the gas side of the mixed fluid passing through a flow path partition member can be reduced further, and ignition property and flame retardance can be improved.

According to the invention according to claim 3, when the inner diameter of the outer peripheral side (nozzle inner wall side) flow path decreases toward the nozzle opening, the flow path cross-sectional area of the mixed fluid between the flow path partition member and the inner wall of the nozzle expands, and fuel particles The flow rate is reduced, and the ignition and flame stability can be further improved.

According to the invention according to claim 4 or 8, on the inner peripheral side (nozzle center side) of the flow path partition member, the effect of canceling the turning by the second turning machine can be uniformly applied to the entire radial direction. Therefore, the mixed fluid with reduced rotation is ejected from the burner opening, so that the mixed fluid does not diffuse excessively in the furnace, and the mixture with the combustion gas (air) such as secondary air and tertiary air is smoothed, and nitrogen oxides It can enhance the inhibitory action of (NOx) production.

According to the invention described in claim 5, the fuel nozzle has the same or monotonically increasing straight pipe shape on the upstream side of the first swirling machine, and communicates with the downstream side of the expanded pipe section whose inner diameter gradually expands, and the downstream side of the expanded pipe section It communicates with the furnace and has a downstream part of a straight pipe shape with an inner diameter larger than that of the upstream side. In the conveying pipe, while conveying at a high flow rate so as not to cause retention of fuel particles with a large particle size, in the furnace opening side, the flow path cross-sectional area is larger than that of the upstream side. By this largely reduced flow velocity, ignition and flame stability can be improved, ensuring the fuel concentration effect.

According to the invention according to claim 6, the concentration of fuel particles outside the fuel nozzle (along the inner wall) of the first swirling machine and the cancellation of the swirling can be effectively effected in the second swirling machine. That is, the first swing machine blade spans the upstream portion in at least a part of the longitudinal direction, and can efficiently impart a radially outward velocity component to the mixed fluid flowing in the upstream portion.

According to the invention described in claim 7, compared to the case where the flow path partition member is not provided, the effect of concentrating the fuel particles to the outside (along the inner wall) of the fuel nozzle can be enhanced, and the effect is hardly lost. In the combination of the first swing machine and the second swing machine as the concentrator, there is no need to provide an excessive swing and to eliminate it. Accordingly, the pressure loss of the burner can be reduced. In addition, the combination of the first and second swirlers as the fuel concentrator can be made compact, and the overall length of the fuel nozzle can be shortened, leading to suppression of the amount of use of the member.

According to the invention according to claim 9, the fuel concentrator can be pulled out in the axial direction of the fuel nozzle to perform maintenance and inspection. Therefore, the workability of maintenance and inspection can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is an overall explanatory drawing of the combustion system of Example 1 of this invention.
It is explanatory drawing of the solid fuel burner of Example 1. FIG.
Fig. 3 is a view seen from the direction of arrow III in Fig. 2;
Fig. 4 is an explanatory view of a flow path partition member of Example 1, in which Fig. 4 (A) is a side view, Fig. 4 (B) is a cross-sectional view taken along line IVB-IVB of Fig. 4 (A), and Fig. 4 ( C) is a diagram corresponding to FIG. 4(B) of the first modification, and FIG. 4(D) is a diagram corresponding to FIG. 4(B) of the second modification.
5 is an explanatory diagram of a comparative example.
6 is an explanatory diagram of a simulation result.
7 is an explanatory view of a boiler (combustion device) having a solid fuel burner according to the present invention, and FIG. It is an explanatory diagram when the solid fuel burner of the present invention is provided in which biomass fuel is used in the uppermost stage, and FIGS. It is explanatory drawing at the time of providing the solid fuel burner of this invention, and FIG.7(C) and FIG.7(E) are the case where the solid fuel burner of this invention using biomass fuel for the uppermost stage on the rear side of a can is provided is an explanatory diagram of

Next, specific examples (hereinafter, referred to as examples) of the embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following examples. In addition, in the description using the following drawings, illustration other than the member necessary for description is abbreviate|omitted suitably for the ease of understanding.

Example 1

BRIEF DESCRIPTION OF THE DRAWINGS It is an overall explanatory drawing of the combustion system of Example 1 of this invention.

In FIG. 1 , in a combustion system (combustion device) 1 of Example 1 used in a thermal power plant or the like, biomass fuel (solid fuel) is accommodated in a bunker (fuel hopper) 4 . The biomass fuel in the bunker 4 is pulverized in a mill (crusher) 5 . The pulverized fuel is supplied to the solid fuel burner 7 of the boiler (furnace) 6 through the fuel pipe 8 and is burned. In addition, a plurality of solid fuel burners 7 are provided in the boiler 6 .

The exhaust gas discharged from the boiler 6 is denitrified in the denitration device 9 . The denitrified exhaust gas passes through an air preheater (10). In the air preheater 10 , heat exchange between the air fed from the blower 11 and the exhaust gas is performed. Therefore, while the exhaust gas is lowered, the air from the blower 11 is heated. The air from the blower 11 is supplied as combustion air to the solid fuel burner 7 and the boiler 6 through the air pipe 12. As shown in FIG.

When the exhaust gas that has passed through the air preheater 10 passes through the gas heater (heat recovery device) 13 , heat is recovered and the temperature is lowered.

As for the exhaust gas that has passed through the gas heater (heat recovery device) 13 , the dry dust collector 14 collects and removes dust and the like in the exhaust gas.

The exhaust gas that has passed through the dry dust collector 14 is transferred to the desulfurization device 15 and desulfurized.

As for the exhaust gas that has passed through the desulfurization device 15 , dust and the like in the exhaust gas are recovered and removed by the wet dust collector 16 .

The exhaust gas that has passed through the wet dust collector 16 is reheated by a gas heater (reheater) 17 .

The exhaust gas that has passed through the gas heater (reheater) 17 is exhausted from the chimney 18 to the atmosphere.

In addition, the structure of the mill 5 itself can use various conventionally well-known structures, for example, since it describes in Unexamined-Japanese-Patent No. 2010-242999 etc., detailed description is abbreviate|omitted.

It is explanatory drawing of the solid fuel burner of Example 1. FIG.

Fig. 3 is a view seen from the direction of arrow III in Fig. 2;

2, 3, the solid fuel burner 7 of Example 1 has the fuel nozzle 21 through which the carrier gas flows. The opening of the downstream end of the fuel nozzle 21 is provided in the wall surface (furnace wall, water pipe wall) 23 of the furnace 22 of the boiler 6 . As for the fuel nozzle 21, the elbow 20 as an example of a curved pipe part is formed at the upstream end of the flow direction of a carrier gas. In the elbow 20, it is bent so that the flow direction of the mixed fluid is bent by approximately 90 degrees. A fuel pipe 8 is connected to the upstream end of the elbow 20 . The fuel nozzle 21 is formed in a hollow cylindrical shape, and in the fuel nozzle 21, a flow path 24 is formed through which a mixed fluid composed of a solid fuel (pulverized biomass fuel) and a carrier gas flows. .

On the outer periphery of the fuel nozzle 21 , a gas nozzle for internal combustion (gas nozzle for secondary combustion) 26 which jets combustion air to the furnace 22 is provided. Moreover, on the outer peripheral side of the gas nozzle 26 for inner side combustion, the gas nozzle for outer side combustion (gas nozzle for tertiary combustion) 27 is provided. Each of the combustion gas nozzles 26 and 27 blows the air from the wind box (wind box) 28 toward the inside of the furnace 22 . In the first embodiment, at the downstream end of the gas nozzle 26 for internal combustion, at the center of the fuel nozzle 21, a guide vane 26a inclined outward in the radial direction (the diameter increases as it goes downstream) is provided. is formed Moreover, the throat part 27a along the axial direction and the enlarged part 27b parallel to the guide vane 26a are formed in the downstream of the gas nozzle 27 for outer side combustion. Accordingly, the combustion air blown out from the respective combustion gas nozzles 26 and 27 is blown out so as to be diffused from the center of the axial direction.

In addition, the flame retainer 31 is supported by the opening at the downstream end of the fuel nozzle 21 .

2 and 3 , an ignition burner (oil gun) 32 is disposed to penetrate through the center of the flow passage cross section of the fuel nozzle 21 . The ignition burner 32 is supported while being penetrated by the collision plate 32a supported by the collision plate flange 20a of the fuel nozzle 21 .

The fuel nozzle 21 is provided with a straight pipe part 21a as an example of an upstream part on the downstream side of the elbow 20 with respect to the flow direction of the mixed fluid. The straight pipe portion 21a is formed in a straight pipe shape with the same cross-sectional area of the flow path 24 .

On the downstream side of the straight pipe portion 21a, an enlarged portion 21b whose inner diameter (ie, cross-sectional area) is enlarged as it goes downstream is connected. On the downstream side of the expanded part 21b, a downstream part 21c of a straight tube shape facing the downstream end and having the same cross-sectional area is connected.

In the first embodiment, the angle θ1 formed by the inner wall of the enlarged portion 21b with respect to the extension line of the straight tube portion 21a is set to 10° to 15°. When θ1 is less than 10°, the length in the axial direction of the fuel nozzle 21 becomes longer, and when θ1 exceeds 15°, separation occurs in the flow of the mixed flow, stagnation occurs in the flow, and stagnant Since there is a problem that fuel tends to be stored in the portion, θ1 is preferably 10° to 15°.

It is not necessarily essential that the shape of the fuel nozzle communicates with a straight pipe, an expanded pipe, and a straight pipe, such as the straight pipe part 21a (= upstream part), the expanded part 21b, and the downstream part 21c from the upstream side. For example, when the flow path partition member mentioned later is provided, ignition property and flame stability will improve, and there may be no problem even if it is a straight tube shape as a whole.

Through the entire nozzle, even if a fuel with coarse particles such as biomass fuel is used, it is not necessary to make the rotation excessively strong. good.

A fuel concentrator 34 is disposed inside the fuel nozzle 21 . The fuel concentrator 34 is supported on an ignition burner 32 . The fuel concentrator 34 has an upstream first swirler 34a and a downstream second swirler 34b.

The first swinging machine 34a has a plurality of first swinging blades 34c formed in a spiral shape with the ignition burner 32 as an axis. Further, the second swinging machine 34b has a second swinging blade 34d inclined in a direction opposite to that of the first swinging blade 34c (reversely winding spiral shape). Each of the turning blades 34c and 34d is not fixed to the inner surface of the fuel nozzle 21 , and the outer peripheral ends of the turning blades 34c and 34d are provided to be spaced apart from the inner surface of the fuel nozzle 21 .

Therefore, in the fuel concentrator 34 of Example 1, when the mixed fluid of fuel and carrier gas passes through the 1st swirler 34a, the turning which turns radially outward is provided. Accordingly, the fuel is concentrated toward the inner wall surface of the fuel nozzle 21 . And when passing through the 2nd turning machine 34b, reverse turning is given and turning becomes weak. Accordingly, on the downstream side of the fuel concentrator 34, the fuel is concentrated to the outer circumferential side of the mixed fluid, and the flow is close to a straight flow.

When arranging the first swirling machine 34a and the second swirling machine 34b in the fuel nozzle 21 having such an expanded tube shape, the first swirling machine 34a is outside the fuel nozzle 21 (inner wall). As for the concentration of fuel particles to ), and for the second swirler 34b, the arrangement in the fuel nozzle is appropriately arranged so that the swirling cancellation is effective, so that the fuel concentration effect and the swirling cancellation effect are less likely to be impaired. It is preferable to set

It is preferable that the blade 34c of the 1st swing machine 34a spans the upstream part (straight pipe part 21a) in (at least part of) the longitudinal direction. Thereby, the velocity component of the radial direction outer direction (nozzle inner wall direction) can be provided with respect to the mixed fluid which has flowed through the upstream part 21a efficiently.

In addition, the end of the first swirler 34a in the longitudinal direction (axial direction of the fuel nozzle) of the blade 34c is the upstream part (straight pipe part 21a on the upstream side) of the fuel nozzle 21 and the enlarged part. It is preferable that it is provided so that it may be located at the same position as the boundary part of 21b (the pipe expansion part communicating with the upstream part), or more downstream, ie, the expanded part 21b side. This is because the recoil of the fuel particles from the nozzle inner wall is reduced and the concentration effect is enhanced. Since it is not necessary to provide excessive turning, the effect of eliminating the turning by the second turning device 34b can be suppressed without increasing too much, and the flow path of the fuel nozzle 21 through the two turning devices 34a and 34b. It is also effective in suppressing an increase in internal pressure loss.

Moreover, with respect to the 2nd turning machine 34b, it is preferable that the blade 34d spans the downstream part 21c (downstream straight pipe part) in (at least a part of) the longitudinal direction. That is, it is preferable that the longitudinal direction (axial direction of the fuel nozzle 21) downstream end of the blade is provided so as to be located on the downstream portion 21c (downstream straight pipe portion) side of the fuel nozzle 21 . Thereby, while suppressing a pressure loss, as the 2nd turning machine 34b, the thing with sufficient swirl cancellation effect can be arrange|positioned at the appropriate space|interval with the 1st turning machine 34a.

In Embodiment 1, the outer diameter D _W1 of the first swing blade 34c is set to 70% as an example with respect to the inner diameter D1 of the straight pipe portion, but is preferably set to 60% to 85%. If it is less than 60%, the rotation imparted is weak and the fuel concentration effect is lowered. Moreover, when it exceeds 85 %, the swirling flow may become too strong.

_{The outer diameter D W2} of the second turning blade 34d is formed to be larger than _{the outer diameter D W1} of the first turning blade 34c _{(ie, D W2} ≥ _{D W1} ). Moreover, in Example 1, it _{is formed with outer diameter D W2} < inner diameter D1. In addition, the outer diameter (D _W2 ) of the second turning blade (34d) with respect to the inner diameter (D2) of the downstream portion (21c), as an example, is set to 65%, preferably set to 55% to 80%. If it is less than 55 %, the effect of canceling a turning by reverse turning becomes low. Moreover, when it exceeds 80 %, it will become difficult to draw out the ignition burner 32 from the fuel nozzle 21 at the time of maintenance. Therefore, in the case of the configuration in which the ignition burner 32 is not drawn, the outer diameter D _W2 may exceed 80% of the inner diameter D2 or the outer diameter D _W2 ≥ the inner diameter D1.

Further, in the first embodiment, the distance from the downstream end fs of the fuel nozzle 21 to the downstream end of the straight pipe portion 21a (=upstream end of the expanded portion 21b) is L1 with respect to the flow direction of the mixed flow. Let L2 be the distance from the downstream end fs of the fuel nozzle 21 to the upstream end of the downstream portion 21c (= the downstream end of the expanded portion 21b), and the downstream end of the fuel nozzle 21 ( When the distance from fs) to the central portion of the second swirler 34b is L4, and the distance from the downstream end fs of the fuel nozzle 21 to the central portion of the first swirler 34a is L5, , in Example 1, as an example, is set as follows.

(1) L2=L4

(2) L5-L4=0.7×D2

(3) L5-L1=0.1×D2

In addition, about (1), it is also possible to set it as L2 ≠ L4.

Regarding (2), it was confirmed by the combustion test that 0.7xD2 to 1.3xD2 were preferable. When it is less than 0.7, before the fuel sufficiently reaches the outer diameter side by the turning of the first turning machine 34a, the turning in the second turning machine 34b is eliminated, and the fuel concentration effect is reduced. When it exceeds 1.3, the resolution of the swirl becomes slow, the swirl remains strong at the downstream end of the fuel nozzle 21, and there is a problem that NOx increases.

About (3), it is preferable to set it as 0xD2 - 0.5xD2. When less than 0, that is, L5-L1<0, most of the first swinging machine 34a is disposed in the enlarged portion 21b, so that the first swinging blade 34c with respect to the inner diameter of the fuel nozzle 21 The ratio of the outer diameter of is relatively decreased, and the fuel concentration effect is lowered. On the other hand, when it exceeds 0.5, the fuel deflected to the outer circumferential side by the swirling circuit provided by the first swirling machine 34a collides with the inner peripheral surface of the fuel nozzle 21 and is easily returned to the radially inner side in a reflected form, so that the fuel the concentration effect is reduced.

That is, in the first embodiment, at least a part of the first swirler 34a is located in the range of the straight pipe portion (upstream portion) 21a of the fuel nozzle 21 . In addition, at least a part of the second swirler 34b is located in the range of the downstream portion 21c of the fuel nozzle 21 . Therefore, when arranging the first swirling machine 34a and the second swirling machine 34b in the fuel nozzle 21 having an expanded tube shape (the expanded portion 21b), for the first swirling machine 34a, the fuel Concentration of fuel particles to the outside (along the inner wall) of the nozzle and the cancellation of the swirling action effectively for the second swirler 34b, and the fuel is less likely to be damaged.

The first whirling machine 34a has its blades 34c in (at least a part of) the longitudinal direction, spanning the upstream portion (straight pipe portion 21a), and efficiently with respect to the mixed fluid flowing through the upstream portion 21a. A velocity component in the radial direction outward (in the direction of the nozzle inner wall) can be given.

Fig. 4 is an explanatory view of the flow path partition member of Example 1, in which Fig. 4 (A) is a side view, Fig. 4 (B) is a sectional view taken along lines IVB-IVB of Fig. 4 (A), and Fig. 4 ( C) is a diagram corresponding to FIG. 4B of the first modification, and FIG. 4D is a diagram corresponding to FIG. 4B of the second modification.

2 and 3 , a flow path partition member 36 is disposed downstream of the fuel concentrator 34 . The flow path partition member 36 is supported by the support member 37 on the inner surface of the fuel nozzle 21 . The flow path partition member 36 of Example 1 is formed in the partial conical shape (conical shape) whose inner diameter is reduced from the upstream end S1 toward the downstream end S2. Accordingly, the flow path dividing member 36 divides the flow path 24 into an outer flow path 24a and an inner flow path 24b.

3 and 4, the support member 37 is formed in a plate shape extending along the radial direction. A plurality of supporting members 37 are arranged at intervals in the circumferential direction. In FIG. 3 , in the first embodiment, the support member 37 is disposed at a position corresponding to between the inner peripheral side projections 31a of the flame retainer 31 .

In FIG. 2, in the solid fuel burner 7 of Example 1, the flow path partition member 36 is arrange|positioned downstream of the fuel concentrator 34. In FIG. Therefore, in the solid fuel burner 7 of Example 1, the flow path partition member 36 is arrange|positioned on the downstream side where the rotation of the fluid on the nozzle center side is weakened by the 2nd swirler 34b, and the flow path is on the outer peripheral side. It is divided and separated into (nozzle inner wall side) and inner peripheral side (nozzle center side). Accordingly, most of the fuel concentrated from the first swing blade 34c of the fuel concentrator 34 toward the inner peripheral wall of the fuel nozzle 21 is supplied to the outer flow passage 24a. Therefore, the flow path partition member 36 hardly interferes with the flow of particles directed radially outward by the fuel concentrator 34, and at the same time, in the outer flow path 24a, the radially outward fuel flows from the inner peripheral wall. Even if it is reflected and is going to face the central axis side again, it is blocked by the flow path partition member 36. As shown in FIG. Therefore, redispersion of fuel particles once concentrated on the outer peripheral side (nozzle inner wall side) by the first swirling device 34a is suppressed, and the concentration effect is maintained to the vicinity of the nozzle opening.

Therefore, compared with the structure described in Patent Document 1 which does not have the flow path partition member 36, even when solid fuel particles obtained by pulverizing biomass fuel having poor ignitability are used, the fuel concentration effect can be ensured. .

In particular, in the first embodiment, the fuel concentrator 34 is not completely fixed to the inner surface of the fuel nozzle 21 . In the configuration in which the fuel concentrator 34 is supported on the inner surface of the fuel nozzle 21, the supporting portion is worn by collision of the fuel particles to be concentrated. Therefore, it is necessary to configure the supporting portion with a wear-resistant special material, and there is a problem in that the cost increases. On the other hand, in Example 1, the fuel concentrator 34 is not supported by the fuel nozzle 21, there is no wear part, and an increase in cost can be suppressed.

Further, in the solid fuel burner 7 of the first embodiment, immediately after the venturi in the fuel nozzle 21, that is, the member imparting the velocity component of the fuel particles in the nozzle center direction passes through the curved pipe portion (elbow 20). It is not a configuration in which a fuel concentrator that imparts a velocity component in a direction away from the center of the fuel nozzle is disposed on the downstream side of the fuel nozzle. That is, it is different from the structure described in patent document 3. In the technique of Patent Document 3, the direction is so that the velocity component of the fuel particles is once given in the direction of the nozzle center in the venturi, and then the velocity component in the direction away from the center of the fuel nozzle is given by the spindle-shaped fuel concentrator. A two-step enrichment operation is performed in reverse. For this reason, it is necessary to secure a certain length of the fuel nozzle, but in relation to other off-furnace equipment, piping, and structures, in order to shorten this, it is necessary to set the contraction of the venturi or the expansion of the fuel concentrator in the radial direction to be abrupt. there will be In the curved pipe upstream of the fuel nozzle, the mixed fluid is bent rapidly, so the distribution of fuel particles in the nozzle cross section is biased. This deflection tends to remain on the downstream side as it is.

On the other hand, in the solid fuel burner 7 described in Example 1, the mixed fluid does not receive the action of the central direction of the fuel nozzle 21 in the flow passage through the curved pipe portion, and the first swirler 34a By this, a velocity component in a direction away from the center of the fuel nozzle 21 is given and the concentration action is completed in one step, so that the length of the fuel nozzle 21 can be shortened compared to the configuration described in Patent Document 3 can If the length of the fuel nozzle 21 can be shortened, there is an advantage in that the degree of freedom in burner installation is increased, and interference with other out-of-furn equipment, piping, and structures can be avoided. In addition, since mixing in the circumferential direction (nozzle inner wall A) is promoted by the effect of the turning, it is difficult to cause a deflection in the distribution of fuel particles in the circumferential direction, which is effective in improving ignition properties and flame stability.

Moreover, in the solid fuel burner 7 of Example 1, it has the flow path partition member 36, and the effect of concentrating fuel particles to the outside (along the inner wall) of the fuel nozzle 21 is high, and the effect is high. Since it is difficult to burn out, in the combination of the first swirler 34a and the second swirler 34b as the fuel concentrator 34, there is no need to provide and eliminate the excessive turning, thereby reducing the pressure loss of the burner. works on In addition, by compacting the combination of the first swirler 34a and the second swirler 34b as the fuel concentrator 34, the overall length of the fuel nozzle 21 can be shortened, and the amount of use of members can be suppressed. goes on

Moreover, in the solid fuel burner 7 of Example 1, compared with the technique of patent document 1, with respect to the mixed fluid containing fuel particles with a large particle diameter, the fuel particle is concentrated along the inner wall of the fuel nozzle 21, and this burner The holding effect up to the opening edge part can be implement|achieved by provision of fewer turns. That is, the fuel particles once concentrated along the inner wall of the fuel nozzle 21 are less likely to be redistributed toward the nozzle center side, or the improvement of ignitability in the vicinity of the flame retarder 31 at the open end due to the reduction of the flow velocity causes the first The strength of turning in the turning machine 34a, that is, the angle of the first turning blade 34c, etc. can be made relatively soft. This leads to being able to relatively soften the effect of canceling the turning in the second turning machine 34b. Thereby, reduction of the pressure loss in the fuel nozzle 21 is attained. Moreover, even if it is a coarse-grained biomass fuel, such as pulverized pellets of a wood-based raw material, since it is difficult to produce a local mixed fluid retention, adhesion of fuel particles to a whirling machine (swiveling blade) is suppressed.

Further, in the first embodiment, the flow path partition member 36 is formed in a conical shape, and the fluid passes between the flow path partition member 36 and the fuel nozzle 21 while passing through the flow path partition member 36 . the flow rate decreases. Then, the concentrated fuel is supplied to the furnace 6 in a state in which the flow rate is reduced. Therefore, ignitability can be ensured even if it is a biomass fuel with low ignitability.

In addition, the flow path partition member 36 of the first embodiment has an outer flow path ( It has a conical shape such that the cross-sectional area of 24a is larger than the cross-sectional area of the outer flow path 24a at the upstream end S1. _{That is, in Example 1, the inner diameter D S1} of the upstream end of the flow path partition member 36 is formed larger than the inner diameter D _{S2 of a downstream end.} In such an inclined shape, the solid fuel particles are more likely to move along the inclined surface than in the case of the cylindrical shape along the axial direction, and thus it becomes difficult to deposit on the upper surface. Moreover, by setting it as D _S1 > D _S2 , the cross-sectional area of the outer peripheral side (nozzle inner wall side) flow path gradually expands toward the nozzle opening part, the flow velocity of fuel particles is decelerated, and it is further effective in improving ignition property and flame stability. there is

_{Moreover, it is preferable that the inclination angle (theta) 2} at which the flow path partition member 36 inclines with respect to the axial direction shall be 10 degrees - 15 degrees. In addition, the _{reason why it is preferable to set θ 2} to 10° to 15° is the same as in the case _{of θ 1 .}

_{In addition, the inner diameter D S1} of the upstream end S1 of the flow path partition member 36 is equal to or larger than _{the outer diameter D W1} of the first turning blade 34c and the outer _{diameter D W2} of the second turning blade 34d. is set to In the case of D _S1 <D _W2 , the carrier gas also flows into the outer peripheral flow path of D _{S1, and the particle concentration concentration effect is weakened.} Therefore, by setting D _S1 ≥ _{D W2} , the particles flow into the outer periphery and the carrier gas is distributed to the outer periphery and the inner periphery, so that there is an effect of concentrating the particle concentration passing through the flow path partition member 36 . From another point of view, since the effect of eliminating the turning by the second turning device 34b is suppressed to the inner periphery side of the flow path (nozzle center side), the retention effect of fuel particle concentration on the outer periphery side (nozzle inner wall side) is further enhanced can keep

_{Moreover, in Example 1, the inner diameter D S2} of the downstream end of the flow path partition member 36 is formed smaller than _{the outer diameter D W2} of the 2nd turning blade 34d. That is, it is set as _{D W2} >D _S2. By setting it as D _W2 >D _S2 , in the inner peripheral side (nozzle center side) of the flow path partition member 36, the cancellation effect of the turning by the 2nd turning machine 34b can be extended to the whole radial direction. Thereby, the mixed fluid weakened in rotation is ejected from the burner opening, the mixed fluid does not diffuse excessively in the furnace 6, and the mixing with the combustion gas (air) such as secondary air and tertiary air is smooth. Thus, it is possible to enhance the suppression effect of nitrogen oxide (NOx) production.

In addition, the flow path partition member 36 of Example 1 is supported by the support member 37 from the inner peripheral wall side of the fuel nozzle 21. As shown in FIG. If the flow path partition member 36 is supported from the central axis (ignition burner 32) side, when the ignition burner 32 and/or the fuel concentrator 34 are maintained and inspected, they are together with the collision plate 32a. When separating from the collision plate flange 20a and drawing out of the furnace, the straight pipe portion 21a cannot pass unless the flow path dividing member 36 and the supporting member 37 are separated. That is, there is a problem in that the workability of the maintenance and inspection work decreases. In contrast, in the first embodiment, the flow path partition member 36 is supported from the inner peripheral wall side of the fuel nozzle 21 , so that maintenance and inspection of the ignition burner 32 and/or the fuel concentrator 34 can be easily performed. can

Moreover, in Example 1, the flow path partition member 36 and the support member 37 (and the fuel concentrator 34) are connected to the furnace 22 side open end (downstream end) fs of the fuel nozzle 21 or It is provided on the upstream side in the fluid flow direction in the fuel nozzle 21 at a distance from the furnace 22 wall surface opening of the solid fuel burner 7 , that is, outside the furnace 22 . More specifically, as shown in FIG. 2 , when the distance from the furnace side opening end fs of the fuel nozzle 21 to the downstream end of the flow path partition member 36 is L3, the distance L3 is the fuel nozzle With respect to the inner diameter D2 in the furnace side opening edge part fs of (21), it is preferable to set it as the range of 0.15xD2 - 1.0xD2. If it is less than 0.15, the flow path partition member 36 becomes easy to receive radiation from a furnace.

Therefore, by setting it to 0.15xD2 or more, the influence of the radiation from the flow path partition member 36 etc. from the furnace (furnace) 22 can be reduced, and the possibility that frequent maintenance is required can be reduced. In addition, it is possible to reduce the risk of ignition even when fuel particles are particularly adhered and deposited on the upper surface of the flow path partition member 36, or the risk of igniting in the fuel nozzle 21 due to the tendency to stay without reaching adhesion and deposition. Therefore, it is possible to easily set the ignition region to the downstream side of the flame retainer 31 .

Moreover, when 1.0*D2 is exceeded, the downstream end S2 of the flow path partition member 36 is too far apart from each position fs and the furnace wall surface opening part. Therefore, the section after the flow velocity reduction in the flow path partition member 36 is lengthened. When the section after the flow velocity reduction becomes longer, there is a problem that the possibility that fuel particles adhere to and deposit on the wall surface of the fuel nozzle 21 increases, or the fuel nozzle 21 becomes long, and the solid fuel burner 7 becomes large.

In the first embodiment, the fuel nozzle 21 has a configuration in which the cross-sectional area of the flow path 24 is the same or monotonically increases over the straight pipe portion 21a, the enlarged portion 21b, and the downstream portion 21c, that is, the cross-sectional area decreases. It is composed of no sections. If there is a section in which the cross-sectional area of the fuel nozzle 21 decreases between the upstream end of the fuel concentrator 34 and the upstream end S1 of the flow path partition member 36, the flow rate increases in the section where the cross-sectional area decreases. (accelerate) And when the flow velocity is decelerated at the position of the flow path partition member 36 after that, so to speak, a flow like a pulsation is formed. In such a case, a region in which the flow velocity F decreases too much occurs, and there is concern about the accumulation and retention of fuel particles.

On the other hand, in Example 1, there is no section in which the cross-sectional area of the flow path 24 decreases, so that a flow such as a pulsation does not occur, and the flow rate F falls into a region of a low flow rate in which the accumulation and retention of fuel particles is concerned. Without this, it is smoothly decelerated (gradually reduced). Accordingly, in the solid fuel burner 7 of the first embodiment, the inside of the fuel nozzle 21 is such that the flow velocity F does not increase (monotonically decreases or becomes the same), and the cross-sectional area becomes monotonically increases or becomes the same (not decreases). not) is set.

Therefore, since the cross-sectional area does not decrease after fuel concentration and the flow velocity does not repeat increase and decrease, the accumulation and retention of fuel are reduced, and the fuel is decelerated and supplied toward the furnace 6 as it is concentrated. That is, in the piping of the fuel nozzle 21, while conveying at a high velocity so as not to cause stagnation of fuel particles having a large particle diameter, the flow velocity is reduced in the opening side of the furnace 6 with a large flow path cross-sectional area than that of the upstream side, thereby igniting the ignition. Performance and flame stability are improved.

2 to 4, the supporting member 37 of the first embodiment is formed in a radial plate shape extending in the radial direction, and has a shape that does not significantly impede the flow of the mixed fluid. Moreover, in Example 1, although the length of the longitudinal direction uses the plate-shaped member of the same length as the flow path partition member 36, the support member 37 is not limited to this, Even if a plate is divided into several, , it is also possible to set it as a rod-shaped member.

The cross-sectional shape of the support member viewed in the nozzle axial direction is not particularly limited as long as it does not impede the flow, and may be a streamlined wing shape (see Fig. 4(C)), a rhombus shape (Fig. 4(D)), or the like. In the case of a wing shape and a diamond shape, since the flow path is once reduced along the flow direction, the concentration of fuel particles is further enhanced, and ignition and flame retardancy are improved.

Here, in the case of a wedge-shaped structure in which the shape of the support member 37 is larger in the circumferential direction toward the downstream side, the wall surface or space facing the opening of the furnace of the support member with respect to the flow direction of the mixed fluid , a vortex occurs in which the mixed fluid flows backwards. Since the said planar part receives radiation from a furnace and becomes high temperature, it is necessary to consider countermeasures, such as use of a member with high heat resistance, coating, etc.. There is also a possibility that fuel particles may adhere, grow or stay due to the above-described vortex generation.

On the other hand, in the support member 37 of Example 1, the thickness direction is formed in the plate shape which opposes the furnace 22, When it sees from the opening surface side of the fuel nozzle 21, it supports several plate shape. The member 37 is arranged so as to be linear. Therefore, compared with the structure described in Patent Document 1, it is difficult to generate a vortex in which the mixed fluid flows backward, and it is possible to suppress adhesion, growth or retention of fuel particles. Moreover, it receives radiation from the furnace 22, and the countermeasure of becoming high temperature is also minimized, and it is economical.

In addition, the support member 37 of the first embodiment is disposed at a position that does not overlap with the protrusion 31a on the inner peripheral side of the flame retainer 31, and compared with the case where it overlaps, the resistance of the flow of the mixed gas is reduced. have.

On the other hand, the cross-sectional shape of the support member 37 viewed in the axial direction of the nozzle is along the flow direction such as a streamlined blade shape, a rhombus, etc., an example in which the flow path is once reduced (shown in FIGS. 4C and 4D ) In the example), since the protrusion of the flame retardant is located downstream of the region where the flow path is reduced once and fuel particles are concentrated (that is, the distribution is generated), there is an effect of improving ignition and flame retardancy.

In Example 1, regarding the inner diameter of the fuel nozzle (primary nozzle) 21, the inner diameter D2 of the opening (downstream end) is set larger than the inner diameter D1 of the straight pipe portion 21a. . On the upstream side (fuel conveyance pipe) of the fuel nozzle 21, in order to prevent fuel particles from adhering and depositing inside the flow path, it is necessary to keep the flow rate of the mixed fluid high to a certain extent, from the viewpoint of ignitability and flame retardancy. In this case, it is necessary to sufficiently reduce the flow rate at the downstream end of the fuel nozzle (primary nozzle) 21 . Therefore, in Example 1, the inner diameter D2 in the downstream end is set larger than the inner diameter D1 of the straight pipe part 21a, and compared with the case of D1≤D2, ignition property and flame retardance are improved. .

(simulation result)

5 is an explanatory diagram of a comparative example.

Next, an experiment (computer simulation) to confirm the effect of Example 1 was performed. In Experiment 1, in the configuration of the first embodiment, the first pivotal were the same as the outer diameter (D _W2) of the diameter (D _W1) and the second turning blades (34d) of the blade (34c). In addition, in Experimental example 2, it was set as the case where the outer diameter D _W2 of the 2nd turning blade 34d was larger than _{the outer diameter D W1} of the 1st turning blade 34c. In Comparative Example 1, an experiment was conducted in the configuration shown in Fig. 5 . That is, in the structure of FIG. 5, neither the enlarged part 21b nor the downstream part 21c of Example 1 is provided. In addition, in the configuration of FIG. 5, as the fuel concentrator, the fuel is concentrated in the radially inner side by reducing the cross-sectional area of the fuel nozzle and not by the turning blade, and then by a member whose diameter increases toward the downstream side supported by the ignition burner. By moving it radially outward, it has the venturi 01 which concentrates fuel on the radially outer side.

In the simulation, the distribution (ratio) of the fuel in the radial direction at the downstream end of the fuel nozzle 21 was measured. The results are shown in FIG. 6 .

6 is an explanatory diagram of a simulation result.

In Fig. 6 , in Comparative Example 1, the ratio of fuel in the radially outer region (1) was small and the fuel ratio in the radial intermediate region (2) was large. That is, the fuel was not concentrated on the outer peripheral side, and the fuel concentration effect was insufficient.

On the other hand, in Experimental Example 1, the fuel was concentrated on the outer peripheral side the most in the ratio of the fuel in the region ① on the outer peripheral side among all the regions ① to ③. Further, in Experimental Example 2, a result in which the ratio of fuel in the region 1 is greater than in Experimental Example 1 is obtained.

Therefore, as in Comparative Example 1, even if the flow path partition member 36 is provided and the fuel concentrator is provided, in the configuration without the enlarged portion 21b, the fuel concentrating effect is not sufficient. On the other hand, by setting it as the configuration having the enlarged portion 21b as in Example 1 (Experimental Examples 1 and 2), the flow rate is reduced through the enlarged portion 21b in which the cross-sectional area is enlarged, and the ignition property is improved, Compared with the structure of Comparative Example 1, the fuel concentration effect is improved and the fuel is concentrated on the outer peripheral side, whereby ignition properties and flame retardancy are further improved.

7 is an explanatory view of a boiler (combustion device) having a solid fuel burner according to the present invention, and FIG. It is an explanatory diagram when the solid fuel burner of the present invention is provided in which biomass fuel is used in the uppermost stage, and FIGS. It is explanatory drawing at the time of providing the solid fuel burner of this invention, and FIG.7(C) and FIG.7(E) are the case where the solid fuel burner of this invention which uses biomass fuel for the uppermost stage on the rear side of a can is provided is an explanatory diagram of

In the form shown to Fig.7 (A), biomass fuel is supplied to the uppermost solid fuel burner 7 among the solid fuel burners 7 . On the other hand, coal as an example of solid fuel is supplied to the solid fuel burner 7' of the middle and lower stage. Coal accommodated in the bunker 4' is pulverized in the mill 5' to become pulverized coal, and is supplied to the solid fuel burners 7 at the middle and lower ends. In each stage, a plurality of solid fuel burners 7 are provided along the furnace width direction of the combustion device 1 .

The form of the solid fuel burner 7' may not necessarily be the solid fuel burner of this invention mentioned above.

As shown in FIG. 1, when biomass fuel is used, biomass fuel with a large particle diameter may fall to the furnace floor as it is unignited. When non-ignited biomass fuel accumulates on the furnace floor, there exists a problem that the frequency of maintenance must be made high, or waste of fuel increases.

On the other hand, in the form shown to Fig.7 (A), biomass fuel is used only in the uppermost solid fuel burner 7 . Therefore, even if unignited biomass fuel is generated in the uppermost solid fuel burner 7, it is ignited and burned out in the middle and lower solid fuel burners 7' until it falls to the furnace floor. easy. In particular, in the boiler 6, in the area|region in which the solid fuel burners 7 and 7' are provided, it becomes easy to become high temperature as it is upward. Therefore, when biomass fuel is used in the uppermost solid fuel burner 7, it is difficult to generate|occur|produce unignited biomass fuel compared with the case where biomass fuel is used in the lower stage solid fuel burner. Therefore, in the form shown to Fig.7 (A), it is difficult for unignited biomass fuel to fall to the furnace floor, and waste of fuel, etc. can be suppressed.

In addition, in the previously installed combustion device 1 having three stages of solid fuel burners on the can front side and the can rear side, it is also possible to change so that only the uppermost solid fuel burner 7 uses biomass fuel. do. Therefore, it is possible to easily convert the existing combustion device 1 using only coal to the combustion device 1 using biomass fuel.

In addition, as shown in FIG. 7(B) and FIG. 7(C), the number of stages of the solid fuel burners 7 and 7' differs in the configuration (or the same number of stages) before and after the can, Also in the configuration in which one is stopped), it is also possible to change so that only one solid fuel burner 7 at the top of the can front side or the can rear side uses biomass fuel.

In addition, in FIG. 1, FIG. 7, although the structure provided with three stages of solid fuel burners 7 and 7' in the up-down direction was illustrated, it is not limited to this. It is also possible to set it as the structure of two or more stages|stages.

At this time, although it is preferable to set it as the uppermost stage as for the solid fuel burner 7 using biomass fuel, it is not limited to this. It is also possible to set it to two or more stages: the uppermost stage and the middle stage.

Further, for example, in the uppermost stage as shown in Figs. 7(D) and 7(E), one solid fuel burner 7 uses biomass fuel, and the other solid fuel burner 7' ), it is also possible to set it as a configuration using pulverized coal. That is, it is also possible to set it as the structure which opposes the solid fuel burner 7 which uses biomass fuel, and the solid fuel burner 7' which uses pulverized coal.

As mentioned above, although the embodiment of this invention was described above, this invention is not limited to the said embodiment, It is possible to implement various changes within the scope of the gist of the present invention described in the claims.

For example, the shape of the support member 37 is not limited to a plate shape, and can be changed to any shape such as a wedge shape, a rhombus shape, or a trapezoid shape.

Moreover, although the structure of the gas nozzles 26 and 27 for combustion of two stages which has the gas nozzle 26 for secondary combustion and the gas nozzle 27 for tertiary combustion was illustrated, it is not limited to this, The gas for combustion It is also possible to make a nozzle into one stage or three stages or more.

In addition, as the fuel concentrator 34, although the structure which has the 1st swing machine 34a and the 2nd swing machine 34b two was illustrated, it is not limited to this. It is also possible to provide three or more, and it is also possible to set it as one. In addition, even when a single vortex device is used, in the flow path partition member 36, the swing becomes weak, so that the mixed fluid after passing through the flow path partition member 36 is ejected in a state in which the swing is weakened. In addition, in consideration of the weakening of the turning in the flow path partition member 36, it is also possible to make the performance of giving the reverse turning of the second whirling machine 34b lower than the performance of giving the turning of the first turning machine 34a. do. That is, changes such as shortening the outer diameter of the second turning blade 34d, decreasing the inclination angle, shortening the length in the axial direction, and the like are possible.

Moreover, although it is preferable to set it as the structure which has the downstream part 21c as the fuel nozzle 21, it is not limited to this. It is also possible to set it as the structure in which it does not have the downstream part 21c, and the downstream end of the enlarged part 21b becomes the downstream end of the fuel nozzle 21. As shown in FIG. At this time, since L2 = 0, L2 ≠ L4.

7: solid fuel burner 21: fuel nozzle
22: furnace 24: flow path of mixed fluid
24a: outer flow path 26, 27: combustion gas nozzle
34: fuel concentrator 34c, 34d: blade
36: flow path partition member

Claims (9)

A fuel nozzle through which a mixed fluid of the solid fuel and its carrier gas flows and opens toward the furnace;
a combustion gas nozzle disposed on the outer periphery of the fuel nozzle and ejecting combustion gas;
A solid fuel burner having a fuel concentrator provided on the central side of the fuel nozzle and providing a velocity component in a direction away from the center of the fuel nozzle to the mixed fluid,
The fuel concentrator has a plurality of blades for imparting rotation to the mixed fluid, and each blade is spaced apart from the inner surface of the fuel nozzle without being completely fixed to the inside of the fuel nozzle. A first swirler disposed on an upstream side of a flow direction, a second swirler disposed on a downstream side of the flow direction of the mixed fluid with respect to the first swirler, wherein the turning direction of the plurality of blades is opposite to the first swirler have a turntable,
A flow path partition member is provided on the downstream side in the flow direction of the mixed fluid with respect to the second swirler for partitioning the flow path of the fuel nozzle to the inside and the outside in the flow path cross section.
solid fuel burner. The method of claim 1,
Outer diameters of the first turning machine and the second turning machine are less than or equal to the inner diameter of the upstream end of the flow path partition member
solid fuel burner. The method of claim 1,
The flow path dividing member, characterized in that the upstream end has a larger inner diameter than the downstream end.
solid fuel burner. 4. The method of claim 3,
An outer diameter of the second revolving machine is smaller than an inner diameter of an upstream end of the flow path partition member and larger than an inner diameter of a downstream end of the flow path partition member
solid fuel burner. A fuel nozzle through which a mixed fluid of the solid fuel and its carrier gas flows and opens toward the furnace;
a combustion gas nozzle disposed on the outer periphery of the fuel nozzle and ejecting combustion gas;
In the solid fuel burner provided on the central side of the fuel nozzle, a fuel concentrator for applying a velocity component in a direction away from the center of the fuel nozzle to the mixed fluid,
The fuel concentrator has a plurality of blades for imparting rotation to the mixed fluid, and each blade is spaced apart from the inner surface of the fuel nozzle without being completely fixed to the inside of the fuel nozzle. A first swirler disposed on an upstream side of a flow direction, a second swirler disposed on a downstream side of the flow direction of the mixed fluid with respect to the first swirler, wherein the turning direction of the plurality of blades is opposite to the first swirler have a turntable,
The flow path of the fuel nozzle has an inner diameter, an upstream portion of the same or monotonically increasing upstream side of the first swirler, an expanding portion communicating with a downstream side of the upstream portion and gradually expanding the inner diameter, and a downstream side of the expanding portion Characterized in that it communicates with and has a downstream part with a constant inner diameter
solid fuel burner. 6. The method of claim 5,
At least a part of the first swirler is located in the range of the upstream part of the fuel nozzle flow path,
At least a part of the second swirler is located in a range downstream of the fuel nozzle passage.
solid fuel burner. 7. The method of claim 6,
a flow path partition member for partitioning a flow path of the fuel nozzle into an inner side and an outer side in a flow passage cross section in a range downstream of the fuel nozzle flow path;
solid fuel burner. 8. The method of claim 7,
The flow path partition member has a shape in which the inner diameter of the upstream end is larger than the inner diameter of the downstream end,
An outer diameter of the second swirler is smaller than an inner diameter of an upstream end of the flow path dividing member and larger than an inner diameter of a downstream end of the flow path dividing member
solid fuel burner. 9. The method according to any one of claims 1 to 8,
The outer diameter of each swirler is less than the inner diameter of the upstream part of the fuel nozzle flow path
solid fuel burner.

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