JPH1019205A - Pulverized fuel combustion device - Google Patents

Abstract

(57) [Problem] To provide a pulverized fuel combustion apparatus capable of promoting ignition of a difficult-to-ignite pulverized fuel and performing stable combustion. SOLUTION: Fine powder fuel is separated into high-concentration fine powder and low-concentration fine powder by a cyclone separator 7, and each fine powder is supplied to a burner nozzle 2. The burner nozzle 2 is arranged so that high-concentration fine powder is supplied toward the inside of the vortex and low-concentration fine powder is supplied toward the outside of the vortex. The ejection port surface of the burner nozzle 2 has an angle inclined with respect to the ejection direction axis so as to be parallel to the inner surface of the furnace.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulverized fuel combustion apparatus used for boiler furnaces, chemical industrial furnaces, and the like.

[0002]

2. Description of the Related Art The applicant of the present invention has previously proposed a pulverized fuel combustion apparatus which is designed to stably ignite a flame-retardant fuel so as to improve flammability (Japanese Patent Laid-Open No. 7-19848).
No. 6). The pulverized fuel combustion device will be described with reference to FIGS.

FIG. 2 is a side view of a boiler according to the embodiment, FIG. 3 is a perspective view showing a configuration of a wind box of the burner in the above embodiment, FIG. 4 is a view showing a plan layout of the burner in the embodiment, and FIG. FIG. 6 is a diagram schematically illustrating a combustion aspect in a furnace according to the embodiment, and FIG. 6 is a longitudinal sectional view illustrating a structure of a burner according to the embodiment.

First, as shown in FIG. 2, the burner nozzle 2 in the pulverized fuel combustion device of this embodiment is disposed on the furnace wall of the boiler furnace 1 so as to be inclined downward, and the injected mixture is ignited to generate buoyancy. As a result, a U-shaped flame 3 is formed.

Next, as shown in FIG. 3, in the configuration of the wind box in the combustion apparatus of the present embodiment, the ports A for the auxiliary combustion air and the ports FD and FL for ejecting the fuel are alternately overlapped in the vertical direction. Ports for ejecting fuel are each provided with two ports FD of a mixture with a high concentration and ports FL of a mixture with a low concentration in a lateral direction.

As shown in FIG. 4, in the combustion apparatus of the present embodiment, high-concentration fine powder is injected toward the inside of the swirling flame vortex 4, and low-concentration fine powder is injected toward the outside of the vortex. . Then, as shown in FIG. 5, a stable high-density combustion zone 5 is formed at the center of the furnace.

The structure of the burner in the combustion apparatus of this embodiment is shown in FIG. 6, and the pulverized fuel carried by the primary air is separated into a rich mixture and a lean mixture by the cyclone separator 7 and the inside of the furnace. It ignites and burns.

[0008]

As described above, FIG.
6, the cyclone separator 7 is provided between the burner nozzle 2 and the pulverized fuel supply pipe.
To separate the high-concentration fine powder and the low-concentration fine powder, supply each fine powder to the burner nozzle 2 and throw the high-concentration fine powder toward the inside of the vortex; By arranging the burner nozzle 2 so as to be injected toward the fuel, stable ignition is possible even in the case of a flame-retardant fuel, and the combustibility is improved.

[0009] Further, since the vicinity of the furnace side wall in this combustion apparatus is in an oxidizing atmosphere with sufficient air, reduction corrosion of the furnace wall tube and adhesion and deposition of minerals in fuel on the furnace wall can be prevented. . In particular, when burning difficult-to-ignite pulverized fuel, it is important to make the flow velocity as low as possible at the burner nozzle ejection part, but there is a limit from the viewpoint of preventing accumulation and the like.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pulverized fuel combustion apparatus which further promotes ignition of a difficult-to-ignite pulverized fuel and can perform more excellent stable combustion.

[0011]

According to the present invention, a plurality of burner nozzles are provided on a furnace wall so that a flame swirls in a furnace to form a vortex and has a U-shaped vertical section. And a fine powder fuel supply pipe is connected to the burner nozzle via a cyclone separator, and the fine powder fuel is separated into high-concentration fine powder and low-concentration fine powder by the cyclone separator, and each fine powder is supplied to the burner nozzle. And a burner nozzle, wherein the burner nozzle is disposed such that high-concentration fine powder is injected toward the inside of the vortex, and low-concentration fine powder is input toward the outside of the vortex. A configuration is adopted in which the surface is inclined at an angle to the ejection direction axis so as to be parallel to the inner surface of the furnace.

In the pulverized fuel combustion apparatus according to the present invention, as described above, the injection surface of the pulverized fuel has an angle inclined with respect to the injection direction axis so as to be parallel to the furnace inner surface. However, the substantial cross-sectional area of the ejection portion increases, and the ejection velocity decreases. Further, the heat receiving surface area of the fuel jet increases, and the temperature of the fuel increases.

Therefore, in the pulverized fuel combustion device according to the present invention, ignition of the hardly ignitable pulverized fuel can be promoted and stable combustion can be performed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a pulverized fuel combustion device according to the present invention will be specifically described based on one embodiment shown in FIG. FIG. 1 shows a burner structure in a pulverized fuel combustion device according to an embodiment of the present invention, and is a longitudinal sectional view similar to FIG.

In the pulverized fuel combustion apparatus shown in FIG.
The tip 2a of the burner nozzle 2 has an angle inclined with respect to the ejection direction axis such that the ejection port surface forms the same plane in parallel with the boiler furnace inner surface 1a.

In the pulverized fuel combustion apparatus according to the present embodiment, the other structure is the same as that of the pulverized fuel combustion apparatus except that the injection port surface of the tip 2a of the burner 2 is formed so as to be parallel to the furnace inner surface 1a and to form the same surface. The structure is the same as that of the pulverized fuel combustion device shown in FIGS. 2 to 6, and a description thereof will be omitted.

In the pulverized fuel combustion device according to the present embodiment, as described above, by making the ejection surface of the burner nozzle 2 parallel to the inner surface of the furnace, it is once ejected downward to form a U-shaped flame. If the gas is blown up in the furnace, the substantial ejection speed can be reduced. In this way, it is possible to promote the ignition of the non-ignitable pulverized fuel and perform stable combustion.

[0018]

As described above, in the pulverized fuel combustion apparatus according to the present invention, the angle of inclination of the burner nozzle of the pulverized fuel with respect to the injection direction axis is parallel to the furnace inner surface. By doing so, the substantial cross-sectional area of the ejection part increases, the ejection velocity decreases, and the ignition is stabilized. Further, the heat receiving surface area of the fuel jet increases, so that the temperature of the fuel can be increased and the ignition can be promoted.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a burner structure in a pulverized fuel combustion device according to an embodiment of the present invention.

FIG. 2 is a side view of an example of a boiler provided with a conventional pulverized fuel combustion device.

FIG. 3 is a configuration diagram of a wind box of a burner in one embodiment of a conventional pulverized fuel combustion device.

FIG. 4 is a plan view of a burner in one embodiment of a conventional pulverized fuel combustion device.

FIG. 5 is a schematic view of a combustion state in a furnace in an embodiment of a conventional pulverized fuel combustion device.

FIG. 6 is a longitudinal sectional view of a burner structure in one embodiment of a conventional pulverized fuel combustion device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Boiler furnace 2 Burner nozzle 3 Flame 4 Swirling flame vortex 5 High concentration combustion area 7 Cyclone separator FD Rich mixture port FL Light mixture port A Combustion auxiliary air port

Claims (1)

[Claims] 1. A plurality of burner nozzles are arranged on a furnace wall such that a flame swirls in a furnace to form a vortex and a vertical section thereof has a U-shape, and the burner nozzle is connected to the burner nozzle via a cyclone separator. A supply pipe is connected, and the pulverized fuel is separated into high-concentration fine powder and low-concentration fine powder by the cyclone separator, and each fine powder is supplied to the burner nozzle, and the high-concentration fine powder is supplied toward the inside of the vortex. A pulverized fuel combustion device in which the burner nozzle is arranged so that low-concentration fine powder is injected toward the outside of the vortex, wherein the burner nozzle has an ejection direction axis such that an ejection surface of the burner nozzle is parallel to an inner surface of the furnace. A pulverized fuel combustion device, characterized in that the device is inclined at an angle to the device.