JP3999749B2 - Combustion apparatus and combustion method - Google Patents

Description

In the present invention, in coal-fired power generation systems, industrial boilers, and the like, a part of the conventional solid fossil fuel such as coal is replaced with an inexpensive biomass fuel while efficiently reducing the amount of CO ₂ generated from the fossil fuel. The present invention relates to a combustion apparatus and a combustion method that enable energy production.

As is well known, co-firing of coal and biomass, which is a solid fossil fuel, is the cost of fuel due to the use of low-priced fuel in combustion equipment that produces energy by combustion in industrial boilers, business boilers, and various turbines. It can be reduced, and can further contribute to the suppression of the amount of CO ₂ generated from fossil fuels. As a result, it can be used for CO ₂ emission trading. Therefore, in recent years, the use of fossil fuels and biomass fuels has been promoted, and in the United States, regulations have been relaxed in addition to renewable use policies.

In recent years, various types of combustion apparatuses that co-fire coal and biomass fuel have been proposed. Conventionally proposed coal-biomass co-firing apparatus is designed for the purpose of replacing as much biomass fuel as possible with respect to the supply amount of coal. This is a matter of course considering the original objectives of reducing fuel costs and reducing the amount of CO ₂ generated from fossil fuels.

  Biomass fuel has significantly improved ignitability and combustibility by drying, but has a drawback that it is difficult to atomize and atomize. On the other hand, coal can be easily pulverized, and the pulverized coal used in conventional coal combustion apparatuses has an average particle size of several tens of μm. On the other hand, since the biomass fuel is much less brittle than coal, the degree of pulverization is only a few millimeters even if a device having a pulverization capacity equal to or higher than that of a pulverizer for pulverizing coal is used. . Therefore, when the biomass itself is dried, the ignitability and combustibility are at a sufficiently high level, but since the particle size is large, when supplying a large amount as fuel to the furnace body of the combustion apparatus, Compared to high coal powder, the ignitability is much worse. Therefore, there arises a problem that in the furnace body, an unburned portion of the biomass fuel is increased, an incomplete combustion state is generated, and generation of CO and NOx is increased. In addition, since the biomass fuel has a large particle size as described above, it is easy to fall after being supplied to the furnace body, and a part of the supply amount remains as unburned material in the furnace bottom, so that the combustion efficiency is raised. There is also a problem that it is not possible.

  In order to solve the above-mentioned problems in the coal-fired and biomass-fuel co-firing device, conventionally, combustion devices with various improvements have been proposed. For example, in the combustion apparatus disclosed in Patent Document 1, “a pulverized solid fossil fuel and a biomass fuel are separately supplied to a combustion furnace by separate systems, and each fuel from both fuel supply channels is burned. As a nozzle to be injected into the furnace, a solid fossil fuel injection nozzle is provided at the center side, a biomass fuel injection nozzle is provided on the outer peripheral side of the solid fossil fuel injection nozzle, and a burner provided at the tip of the biomass fuel injection nozzle. By providing the flame plate, "the above-mentioned problem is being solved. That is, in this combustion apparatus, a biomass fuel jet port having a ring-shaped opening for jetting biomass fuel is formed on the outer periphery of a jet port for jetting pulverized coal, and a secondary air jet port is further provided on the outer periphery of the biomass fuel jet port. Is provided, and the combustion direction of the biomass fuel is improved by surrounding the combustion direction with the baffle plate called a flame-holding plate.

  Not only the combustion apparatus disclosed in Patent Document 1 but the conventional combustion apparatus has different combustion characteristics such as ignitability, combustibility, and floatability due to flame between pulverized coal and biomass fuel. Control of supply amount and supply ratio, control of furnace temperature, control of supply air quantity into the furnace are subtle, and the above problems in mixed-burning equipment, namely, low combustion efficiency of biomass fuel, CO and NOx generation The present situation is that the purpose such as the suppression of the above is not fully achieved.

JP 2003-222310 A

As described above, in a combustion apparatus that co-fires coal and biomass, complete combustion of biomass fuel is important in order to achieve the objectives of reducing fuel costs and suppressing CO and NOx generation by co-firing biomass fuel. However, the conventional combustion apparatus does not sufficiently realize the complete combustion of the biomass fuel.
The present invention has been made in view of such circumstances, and the problem is that in a combustion apparatus that co-fires solid fossil fuel and biomass fuel, complete combustion of biomass and improvement of combustion characteristics of the entire combustion apparatus are achieved. There is to plan.

  The inventors of the present invention have proposed various improvements in the conventional co-firing device, and have attempted to improve the combustibility of biomass fuel, but have not been sufficiently effective compared to the cost of development, Considering the original purpose of fuel use, it is necessary to increase the alternative amount of fossil fuel as much as possible, but considering the need to realize complete combustion, we will consider new ways of mixed combustion equipment did. As a result, if the amount of combustion treatment gives priority to at least complete combustion, and if the biomass combustion burner can have not only the function of burning biomass but also an additional function, the shortage of the amount of combustion treatment can be compensated. It came to a conclusion that a mixed-burning device that can withstand practical use can be provided. From such a viewpoint, when a specific configuration was examined, the following findings were obtained.

That is, the problem with the conventional co-firing device is that the biomass fuel falls into incomplete combustion in the furnace. First, the biomass fuel obtains a sufficient amount of oxygen necessary for complete combustion because it is mixed with pulverized coal. Secondly, since the amount of biomass fuel supplied is large, an amount that falls before being burned in the furnace is generated.
In contrast, the size of the biomass spout is sufficiently smaller than that of the pulverized coal spout, and the biomass fuel spout is installed on the pulverized coal spout so that it does not burn in a mixed state of biomass fuel and pulverized coal. By knowing that the position can be devised, the biomass fuel itself can be fully combusted by taking advantage of its ignitability and combustibility, and that the biomass combustion flame can play a role as an ignition torch for pulverized coal combustion It came to.

The present invention has been made based on such knowledge. That is, the combustion apparatus according to [Claim 1] of the present invention is a combustion apparatus that supplies and burns solid fossil fuel and biomass fuel into the furnace body, and the furnace body is used as a main combustion burner and an ignition torch. A burner is attached, a solid fossil fuel supply flow path is connected to the main combustion burner, a biomass fuel supply flow path is connected to the ignition torch combined burner, and the ignition torch combined burner and the biomass fuel supply are connected connection with the flow path, the main Ri outer der combustion burner, the ignition torch spout of combined burner, the windbox which is provided on the outer periphery of said main burner jets and the main burner two The firing port of the ignition torch and burner is located at the inner corner of the ejection port of the main combustion burner. To.

[Claim 2 ] of the present invention relates to a combustion method, and this combustion method is a combustion method in which solid fossil fuel and biomass fuel are supplied into a furnace body and burned, and the furnace body is opened. A biomass fuel combustion burner and a biomass fuel supply flow path for supplying biomass fuel are connected to the outside of the solid fossil fuel combustion burner that opens in the furnace body, and the biomass fuel is supplied from the biomass fuel supply flow path. And the biomass fuel combustion burner outlet spans between the solid fossil fuel combustion burner outlet and the secondary air outlet of the wind box provided on the outer periphery of the solid fossil fuel combustion burner. The biomass combustion burner outlet is located at the inner corner of the solid fossil fuel combustion burner outlet and opens into the furnace body. Combustibility of the solid fossil fuel is improved by using a combustion burner of biomass fuel as an ignition torch.

  The combustion apparatus and the combustion method according to the present invention allow complete combustion by separating a relatively small amount from pulverized coal and combusting it, and also exhibits the good ignitability and combustibility inherent in biomass. The combustion flame can serve as an ignition torch, and has an effect of stabilizing the combustion flame of a solid fossil combustion burner that burns a large amount of pulverized coal.

  Embodiments of a combustion apparatus and a combustion method according to the present invention will be described below in detail with reference to the drawings. Note that the embodiments described below are merely examples for suitably explaining the present invention, and do not limit the present invention.

  In the present invention, biomass refers to biological resources. Examples of biomass include agricultural products or by-products, wood, plants, and the like. Depending on the purpose of biomass conversion, from the viewpoint of fuel and raw material supply, those that are easily available in large quantities and those that have a stable supply as fuel and raw materials, such as those with fast growth and growth rates, are available. preferable. Examples of plant biomass of plants and trees include corn, rice, sugar cane such as sweet sorghum, pastures such as napier grass, and wood. Moreover, in this invention, you may use the organic waste etc. which can be used as an alternative raw material of biomass.

(First embodiment)
1, 2 and 3 are views showing a first embodiment of a combustion apparatus according to the present invention. FIG. 1 is a plan sectional view of a main part including a combustion burner and its vicinity of the combustion apparatus of the present invention, FIG. 2 is a side sectional view of the main part, and FIG. 3 is an end view of the opening of the combustion burner. .
Reference numeral 1 in the figure denotes a furnace body, and a main combustion burner 2 and an ignition torch combined burner 3 are attached to the furnace body 1. A solid fossil fuel (coal) supply channel 4 is connected to the main combustion burner 2, and a biomass fuel supply channel 5 is connected to the ignition torch and burner 3. A wind box 6 is formed on the outer periphery of the main combustion burner 2, and the secondary air 7 is jetted to the entire outer peripheral portion of the jet outlet 2 a of the main combustion burner 2.

  The outlet 3 a of the ignition torch combined burner 3 is located at the inner upper corner of the outlet 2 a of the main combustion burner 2. More precisely, it is arranged so as to straddle the jet outlet 3 a and the secondary air jet outlet 6 a by the wind box 6.

  The raw coal of the pulverized coal 8 as the main fuel is supplied into a coal mill (not shown) together with hot air for conveyance at a temperature of about 200 ° C., and is pulverized simultaneously with drying inside to become pulverized coal. And is supplied to the solid fossil fuel supply channel 4.

  Biomass as a raw material for one of the fine biomass fuels 9 is dried and pulverized in a biomass mill (not shown) together with a hot gas for transportation, like coal, to become fine biomass, which is transported by hot air and supplied with the biomass fuel. It is supplied to the flow path 5. The mixing ratio of the fine biomass fuel 9 and hot air at this time is set to a range where the biomass fuel 9 is completely burned and the combustion flame is stable and sustainable at the jet outlet of the ignition torch / burner 3.

  According to the said structure, since the biomass fuel 9 supplied to the ignition torch combined use burner 3 is conveyed by sufficient quantity of hot air, combustion of the jet nozzle 3a of the burner 3 becomes complete combustion. Moreover, since the spout 3a is located at a position across the spout 6a of the secondary air 7 at the upper corner of the spout 2a of the pulverized coal 8, a part of the hot air that has transported the biomass fuel 9 is part of the pulverized coal 8. Even if it may be eaten by combustion, a sufficient amount of air is supplied from the adjacent secondary air 7, so that the complete combustion of the biomass fuel 9 is not hindered and a stable combustion flame is maintained. be able to. Therefore, the biomass combustion flame maintained at the jet outlet 3a functions as an ignition torch, and even when the combustion flame of the pulverized coal 8 formed at the jet outlet 2a becomes unstable, the pulverized coal is immediately ejected. 8 can be ignited, and the combustion of the pulverized coal as the main fuel can be stably maintained. In this way, the biomass fuel is completely burned at the jet outlet 3a of the ignition torch / burner 3, so even a biomass fuel 9 having a diameter of several millimeters is immediately burned at the jet outlet 3a. Part of the biomass fuel that has been dropped does not fall and accumulate as unburned material on the bottom of the furnace.

In the combustion apparatus of the present embodiment, complete combustion of biomass fuel can be realized, and the combustion flame of biomass fuel can serve as an ignition torch for combustion of pulverized coal, which is the main fuel. That is, according to the present apparatus, in the coal combustion apparatus, it is possible to improve the ignitability and combustibility, and the biomass can be used in complete combustion, and the reduction of CO ₂ originating from fossil fuels, Furthermore, NOx reduction can be realized. Compared with conventional mixed-fired equipment, this equipment reduces the amount of biomass that can be completely burned, and saves space for biomass fuel without significantly remodeling existing coal-fired equipment. The apparatus has an excellent advantage that the apparatus can be completed by a simple construction requiring only a burner and a supply flow path. Therefore, if the characteristic configuration of the present invention apparatus is applied to many existing coal combustion apparatuses, the total biomass processing amount becomes extremely large, and the effects of reducing expensive coal fuel and reducing CO ₂ are , Become enormous. The benefits that can be realized simply and at low cost in terms of equipment are immeasurable.

(Second Embodiment)
4, 5 and 6 are diagrams showing a second embodiment of the combustion apparatus. Figure 4 is a plan sectional view of a main part including a combustion burner and the vicinity thereof of the combustion device, FIG 5 is a side sectional view of the essential portion, FIG. 6 is an end view of the opening of the burner. 4, FIG. 5, and FIG. 6, the same components as those of the apparatus shown in FIG. 1, FIG. 2, and FIG.

  The feature of the present embodiment is that the jet outlet 13a of the ignition torch / burner 13 is located in the center of the inner side of the jet outlet 2a of the main combustion burner 2, and the arrangement structure of the remaining components is as described above. This is the same as the first embodiment. In such an arrangement structure, the jet outlet 13a of the ignition torch / burner 13 is located in the center of the jet outlet 2a of the main combustion burner 2, so that the injection torch combines with the ignition torch / burner 3 of the first embodiment. Oxygen deficiency is more likely at the outlet 13a. Therefore, in the present embodiment, the mixing ratio of hot air in the biomass fuel-hot air mixed fluid supplied to the biomass fuel supply flow path 5 is not increased as compared with the case of the first embodiment. The amount of hot air blended in the illustrated biomass crushing mill is adjusted. By increasing the distribution amount of the hot air that conveys the biomass fuel 9 in this way, the combustion of the biomass fuel 9 can be achieved even if the discharge port 13a of the ignition torch / burner 13 is arranged in the center of the outlet 2a of the main combustion burner 2. The biomass fuel 9 can be completely combusted at the jet nozzle 13a and maintain a stable combustion flame without causing a shortage of working oxygen. And by this stable combustion flame of the biomass fuel 9, the ignitability and combustibility of the pulverized coal 8 which is the main fuel can be well maintained.

Therefore, also by the combustion apparatus of the present embodiment, the same operational effects as the operational effects obtained by the combustion apparatus of the first embodiment can be obtained. That is, in the combustion apparatus of the second embodiment, complete combustion of biomass fuel can be realized, and the combustion flame of biomass fuel can serve as an ignition torch for combustion of pulverized coal, which is the main fuel. . That is, according to the present apparatus, in the coal combustion apparatus, it is possible to improve the ignitability and combustibility, and the biomass can be used in complete combustion, and the reduction of CO ₂ originating from fossil fuels, Furthermore, NOx reduction can be realized. Compared with conventional mixed-fired equipment, this equipment reduces the amount of biomass that can be completely burned, and saves space for biomass fuel without significantly remodeling existing coal-fired equipment. The apparatus has an excellent advantage that the apparatus can be completed by a simple construction requiring only a burner and a supply flow path. Thus, by applying the characterizing feature of the This equipment to the existing number of coal combustion apparatus, biomass throughput of total it becomes very abundant ones, reducing expensive coal, and reduction of CO ₂ is , Become enormous. The benefits that can be realized simply and at low cost in terms of equipment are immeasurable.

(Third embodiment)
7 and 8 are diagrams showing a third embodiment of the combustion apparatus. Figure 7 is a plan sectional view of a main part including a combustion burner and the vicinity thereof of the combustion device. FIG. 8 is an end view of the opening of the burner. 7 and 8, the same components as those of the apparatus shown in FIGS. 1 to 6 described above are denoted by the same reference numerals, and description thereof will be simplified.

  The feature of the present embodiment is that the injection port 23a of the ignition torch and burner 23 is located outside the injection port 2a of the main combustion burner 2, and the arrangement structure of the remaining components is the first structure. This is the same as in the second embodiment. More precisely, the jet outlet 23 a is arranged on the outer side of the wind box 6 provided on the outer periphery of the main combustion burner 2. In this arrangement structure, the jet outlet 23a of the ignition torch / burner 23 is further away from the jet outlet 2a of the main combustion burner 2 and is adjacent to the secondary air jet outlet 6a. There is no shortage of oxygen, and the biomass fuel 9 is easily burned completely, and the combustion flame continues to be stable.

Therefore, even with the combustion apparatus according to the present embodiment, the same effects as those obtained with the combustion apparatuses according to the first and second embodiments can be obtained. That is, in the combustion apparatus of the third embodiment, complete combustion of biomass fuel can be realized, and the combustion flame of biomass fuel can serve as an ignition torch for combustion of pulverized coal, which is the main fuel. . That is, according to the present apparatus, in the coal combustion apparatus, it is possible to improve the ignitability and combustibility, and the biomass can be used in complete combustion, and the reduction of CO ₂ originating from fossil fuels, Furthermore, NOx reduction can be realized. Compared with conventional mixed-fired equipment, this equipment reduces the amount of biomass that can be completely burned, and saves space for biomass fuel without significantly remodeling existing coal-fired equipment. The apparatus has an excellent advantage that the apparatus can be completed by a simple construction requiring only a burner and a supply flow path. Thus, by applying the characterizing feature of the This equipment to the existing number of coal combustion apparatus, biomass throughput of total it becomes very abundant ones, reducing expensive coal, and reduction of CO ₂ is , Become enormous. The benefits that can be realized simply and at low cost in terms of equipment are immeasurable.

  In each of the above embodiments, the shape of the burner is illustrated as a rectangular tube shape, but it may be a cylindrical tube shape. Similarly, in the third embodiment, the shape of the ignition torch / burner is illustrated as a rectangular tube shape, but may be a cylindrical tube shape. Further, in each embodiment, the head of the main combustion burner may be configured to be tiltable with respect to the burner body. In this case, in the structures of the first and second embodiments, it is preferable that the head of the ignition torch / burner is also tiltable integrally. Since such a burner head tilting mechanism can be provided using a conventional mechanism, a detailed description thereof is omitted here.

As described above, in the combustion apparatus and combustion method of the present invention, complete combustion of biomass fuel can be realized, and the combustion flame of biomass fuel serves as an ignition torch for combustion of pulverized coal, which is the main fuel. Can do. That is, according to the present combustion apparatus and combustion method, in the coal combustion apparatus, the ignitability and combustibility can be improved, and the biomass can be used in complete combustion, and CO originating from fossil fuels can be used. Reduction of ₂ and further reduction of NOx can be realized. Compared to conventional mixed combustion devices and combustion methods, this combustion device and combustion method reduce the amount of biomass that can be processed. However, it is possible to achieve complete combustion of biomass fuel, and the existing coal combustion device is greatly modified. Without having to do so, the apparatus can be completed with a simple construction that simply attaches a space-saving burner for biomass fuel and a supply flow path. Therefore, if the characteristic configuration of the present invention apparatus is applied to many existing coal combustion apparatuses, the total biomass processing amount becomes extremely large, and the effects of reducing expensive coal fuel and reducing CO ₂ are , Become enormous. The benefits that can be realized simply and at low cost in terms of equipment are immeasurable.

It is a plane sectional view of the principal part containing the combustion burner of the combustion device of a 1st embodiment of the present invention, and its neighborhood. It is a sectional side view of the principal part containing the combustion burner of the combustion apparatus of the 1st Embodiment of this invention, and its vicinity. It is an end view of the opening part of the combustion burner of the combustion apparatus of the 1st Embodiment of this invention. A plan sectional view of a main part including a combustion burner and its vicinity of a combustion device of the second embodiment. It is a side sectional view of a main part including a combustion burner and its vicinity of a combustion device of the second embodiment. It is an end view of the opening of the combustion burner of a combustion device of the second embodiment. A plan sectional view of a main part including a combustion burner and its vicinity of a combustion device of the third embodiment. It is an end view of the opening of the combustion burner of a combustion device of the third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Furnace body 2 Main combustion burner 2a Outlet 3, 13, 23 Ignition torch combined burner 3a, 13a, 23a Outlet 4 Solid fossil fuel supply flow path 5 Biomass fuel supply flow path 6 Wind box 6a Secondary air outlet 7 2 Secondary air 8 Pulverized coal 9 Biomass fuel

Claims (2)

A combustion device for supplying solid fossil fuel and biomass fuel into the furnace body and burning them,
A main combustion burner and an ignition torch combined burner are attached to the furnace body, a solid fossil fuel supply passage is connected to the main combustion burner, and a biomass fuel supply passage is connected to the ignition torch combined burner With
The connection ignition torch combined burner and the biomass fuel supply passage, Ri outer der of the main burner,
The outlet of the ignition torch combined burner is provided so as to straddle the outlet of the main combustion burner and the secondary air outlet of the wind box provided on the outer periphery of the main combustion burner,
2. A combustion apparatus according to claim 1, wherein an outlet of the ignition torch combined burner is located at an inner corner of the outlet of the main combustion burner . A combustion method in which solid fossil fuel and biomass fuel are supplied into the furnace body and burned,
A biomass fuel combustion burner that opens to the furnace body and a biomass fuel supply passage that supplies biomass fuel are connected outside the solid fossil fuel combustion burner that opens to the furnace body,
Supplying the biomass fuel from the biomass fuel supply channel,
The biomass fuel combustion burner outlet is disposed so as to span between the solid fossil fuel combustion burner outlet and the secondary air outlet of the wind box provided on the outer periphery of the solid fossil fuel combustion burner. And
The biomass combustion burner outlet is located at the inner corner of the solid fossil fuel combustion burner outlet,
A combustion method characterized by improving the combustibility of the solid fossil fuel by using a combustion burner of biomass fuel opened in the furnace body as an ignition torch.

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