glow plug

Abstract

Invention details;

Description

Burner

[0001] The present invention relates to a burner that can be fueled by a solid powder fuel such as pulverized coal, a gas, or a liquid fuel.

[0002] The present applicants have proposed a burner that has a concentric flow path for solid powdered fuel and multiple air flow paths, which can reduce the amount of nitrogen oxides generated while maintaining the quality of the cement clinker being burned, and can form an optimal flame depending on the type of solid powdered fuel being used while maintaining mechanical reliability (Patent Document 1).

[0003] The air flow path is a four-channel system consisting of a solid powder fuel flow path, a first air flow path located adjacent to the solid powder fuel flow path on the outside and mainly swirling, a second air flow path located adjacent to the first air flow path on the outside and mainly straight, and a third air flow path located adjacent to the solid powder fuel flow path on the inside and mainly swirling. By independently controlling the air flows of these four channels, it is possible to reduce the amount of nitrogen oxides generated while also ensuring the combustibility of the solid powder fuel.

[0004] Japanese Patent Application Publication No. 2003-279003

[0005] While the burner described above is effective, its use of four air channels requires a large amount of air drawn directly from the atmosphere (hereinafter referred to as "primary air"), resulting in increased fuel consumption due to the increased temperature of the primary air. On the other hand, reducing the amount of primary air reduces momentum, leading to poor combustion of solid powdered fuel. Furthermore, the large number of air channels (four) increases the burner's cross section (perpendicular to the axis) and its overall weight. Furthermore, because the burner is inserted into the kiln from the side of the kiln mantle, its overall length is long, resulting in a cantilevered configuration. Therefore, the heavy burner, when installed in a cantilevered configuration, is prone to misalignment.

[0006] Therefore, the present invention has been made in consideration of the problems with the conventional burners described above, and aims to provide a burner that reduces the amount of primary air while maintaining high momentum, reduces the overall weight of the burner, and is less likely to become displaced.

[0007] In order to achieve the above object, the present invention provides a burner comprising a cylindrical body, a cylindrical cavity penetrating the body in the axial direction, and a flow path arranged outside the cavity, wherein fuel and primary air flow through the flow path, and high-temperature air (hereinafter referred to as "secondary air") recovered from a cooler downstream of the kiln flows axially inside the cavity and along the outer peripheral surface of the body.

[0008] According to the present invention, since only the fuel flow exists in the main body other than the cavity (single-channel system), the cross-section of the burner can be reduced, allowing for a lighter burner, reducing positional deviation due to the burner load and improving handling. Furthermore, by increasing the fuel flow velocity, the ejector effect can be achieved, drawing in secondary air from the outer surface of the burner and the cavity, allowing the secondary air to sandwich the fuel flow even in a single channel with only the fuel flow. In other words, by using secondary air to form a flow similar to the primary air in a four-channel burner, combustibility is maintained. Furthermore, because the secondary air is hot, the combustion rate is faster. Furthermore, by increasing the fuel flow velocity, high momentum can be achieved even with a small amount of primary air, improving combustibility.

[0009] In the burner, the cross section of the flow passage disposed outside the cylindrical cavity may be ring-shaped.

[0010] By making it possible to hang the burner from above, the overall length of the burner can be significantly shortened compared to conventional burners, which contributes to reducing the burner's weight. In addition, since the fuel can be transported by dropping it from above, the amount of primary air can be reduced. This reduces the amount of nitrogen oxides emitted from the firing device and the amount of fuel used.

[0011] Furthermore, by making the burner movable in the axial direction of the burner, the position of the burner can be easily adjusted. The burner body is lightweight, which improves handling when adjusting the position. The horizontal section of the burner is short, which makes it less likely for fuel to accumulate or for the flow path to wear out. In addition, the short horizontal section, where the gas flow velocity is high and which accelerates the fuel, reduces pressure loss.

[0012] As described above, according to the present invention, it is possible to provide a burner that reduces the amount of primary air while maintaining high momentum, reduces the overall weight, and is less likely to become displaced.

[0013] 1A and 1B are diagrams showing an embodiment of a burner according to the present invention, in which (a) is a front view and (b) is a vertical cross-sectional view.

[0014] Next, an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, a case where a burner according to the present invention is used as a burner for a cement kiln will be exemplified.

[0015] FIG. 1 shows one embodiment of a burner according to the present invention. This burner 1 comprises an overall cylindrical body 1a, a cylindrical cavity 1b extending axially from the body 1a, and a solid powdered fuel passage 1c with a ring-shaped cross section located outside the cavity 1b. The cavity 1b is configured so that its cross section is larger at the rear end 1f than at the front end 1e of the burner 1, allowing solid powdered fuel (hereinafter referred to as "fuel") F, such as pulverized coal, to be ejected at high speed from the front end 1e. A large-diameter portion 1d is formed on the outer periphery of the burner 1, excluding the front end 1e, and acts to direct secondary air A2 from a clinker cooler 13 (see FIG. 2) toward the center of the burner 1. The cross section of the solid powdered fuel passage 1c is not limited to a ring shape and can have other shapes.

[0016] As shown in Figure 2, the burner 1 is suspended from above the kiln front mantle 3 of the cement kiln 2. By adopting a suspended type, the overall length of the burner 1 can be significantly reduced compared to conventional burners.

[0017] Above the kiln mantle 3, there are provided rails 4, a movable part 6 that can move on the rails 4 via wheels 7, and a support part 5, and the burner 1 is supported so that it can move in the axial direction of the cement kiln 2 (axial direction of the burner 1) and in the vertical direction.

[0018] Above the furnace mantle 3, there are arranged a fuel F storage tank 8, a feeder 9, rotary valves 14 and 15, a chute 10, a blower 11, and a conveying pipe 12, and the fuel F in the storage tank 8 is dropped and supplied to the burner 1 by the blower 11. By supplying the fuel F by dropping it, the amount of primary air A1 can be reduced.

[0019] Next, a cement burning method using the burner 1 will be described with reference to FIGS.

[0020] Before operating the cement kiln 2, the position of the burner 1 is adjusted appropriately. This position adjustment is performed by the movable part 6 and the support part 5 so that the tip 1e of the burner 1 is in an optimal position in the axial direction and the vertical direction of the cement kiln 2. In this case, by making it possible to hang the burner 1 from above the front-of-kiln mantle 3 of the cement kiln 2, the overall length of the burner 1 can be significantly shorter than before, and the reduced weight of the burner makes it easier to handle and less likely to become displaced after installation.

[0021] During cement burning, fuel F is dropped from storage tank 8 through feeder 9, rotary valves 14 and 15, and chute 10, and is then supplied to burner 1 by blower 11 via conveying pipe 12. Conveying air from blower 11 becomes primary air A1 and flows through solid powder fuel flow path 1c, but primary air A1 does not flow inside or outside the body of burner 1. By increasing the fuel flow ejection speed, an ejector effect is created, which draws in secondary air A2 from the outer peripheral surface side of large diameter portion 1d of burner 1 and cavity 1b, and supplies it to cement kiln 2. This enables combustion with high momentum even with a small amount of primary air A1.

[0022] In the above embodiment, the burner 1 according to the present invention is used as a burner for a cement kiln, but it can be used in any industrial furnace other than a cement kiln, such as a baking furnace, a heating furnace, a drying furnace, or a preheating furnace.

[0023] In addition, although the case where solid powder fuel is used as fuel has been exemplified, gas or liquid fuel can be used instead of solid powder fuel, and in that case, the solid powder fuel flow passage 1c becomes a gas flow passage or a liquid fuel flow passage. The illustrated embodiment is merely an example and is not intended to limit the technical scope of the present invention.

[0024] REFERENCE SIGNS LIST 1 burner 2 cement kiln 3 kiln front mantle 4 rail 5 support part 6 moving part 7 wheel 8 storage tank 9 feeder 10 chute 11 blower 12 conveying piping 13 clinker cooler 14, 15 rotary valve A1 primary air A2 secondary air F fuel

Claims

DEPCT681. A burner comprising: a cylindrical body, a cylindrical cavity extending through the body in the axial direction, and a flow passage arranged outside the cavity through which primary fuel and air flow, and secondary air flows within the cavity and along the surfaces along the outer circumference of the body; 2. A burner as claimed in claim 1, in which it has an annular cross-section; 3. A burner as claimed in claim 1 or 2, in which it can be suspended from above; 4. A burner as claimed in claim 1 or 2, in which it can move in its axial direction;

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