JP3388951B2 - Pulverized fuel combustion device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulverized fuel combustion apparatus applied to a boiler furnace for thermal power generation, a chemical industrial furnace, and the like. FIG . 6 is a horizontal sectional view showing an example of a conventional pulverized fuel combustion apparatus. In the figure, (1) is a burner nozzle, (2) is a burner nozzle opening surface, (3) is a fine powder fuel supply pipe, (4) is a combustion auxiliary air supply path, (5) is a wind box, and (6) is a furnace. The wall tube, (7) shows the furnace side, and (11) shows the extension of the furnace side. [0003] The mixed flow of the pulverulent fuel and the carrier air passes through the pulverulent fuel supply pipe (3), is led to the burner nozzle (1), and is ejected from the burner nozzle opening surface (2) into the furnace. . The combustion auxiliary air passes through the combustion auxiliary air supply passage (4) and is guided to the burner nozzle (1), and the burner nozzle opening surface (2) like the pulverized fuel and the carrier air.
Spouts out of the furnace. The vertical plane passing through the ejection direction axis (8) is not perpendicular to the furnace side surface (7) but is inclined. The jetted pulverized fuel, carrier air and combustion auxiliary air form a flame while diffusing and mixing in the furnace. At this time, if the flame collides with the furnace wall tube (6) or a phenomenon such as licking the furnace wall tube (6) occurs, the flame is cooled by the furnace wall tube (6) and unburned ash in the ash is removed. Therefore, there is a possibility that deterioration of flammability such as an increase in the amount of clinker and so-called clinker trouble that the clinker adheres to the furnace wall tube (6) may occur. Therefore, conventionally, in order to prevent the flame from colliding with the furnace wall tube (6), the furnace wall tube located near the burner nozzle (1) is arranged on the extension surface (11) of the furnace side surface. In consideration of the spread of the flame, the wind box (5) is formed at an angle α with the furnace side (7) as shown by reference numeral (26).
They were arranged side by side. [0004] The axis of the ejection direction in which the auxiliary combustion air is ejected into the furnace is coaxial with the axis (8) of the ejection direction in which the pulverized fuel and the carrier air are ejected into the furnace. The cross-sectional shape of the burner nozzle (1) is symmetrical with respect to the vertical plane passing through the ejection direction axis (8). FIG . 7 is a conceptual view (plan view) of a structure of a furnace wall tube (6) disposed around the above-mentioned conventional pulverized fuel combustion apparatus, that is, a so-called burner panel structure. Each wire element shown in the figure means one furnace wall tube (6). The above-mentioned conventional pulverized fuel combustion device is designed to prevent unburned ash in ash from increasing and clinker trouble as shown in the above-mentioned reference numeral (26). The furnace side (7) is arranged at an angle α so as to line up toward the wind box (5), and has a structure capable of fully exhibiting its performance. However, adopting such a structure has caused the following problems, and improvements have been required. 1) Since a part (26) of the furnace wall tube is not located on the same plane as the furnace side surface (7) or the extension surface (11) of the furnace side surface, it is not easy to work the furnace wall tube panel and the burner panel. . 2) The furnace wall support structure has a complicated structure. 3) In the case of a large-capacity burner or a large-capacity boiler, the length L of the furnace wall tube row indicated by reference numeral (26) in FIG. 6 increases in the furnace width or the furnace depth. Access to the surroundings of the furnace wall becomes difficult, which may cause inconvenience to maintenance. 4) Since the burner nozzle (1) is relatively arranged outside the furnace, the maintainability is easily impaired. [0010] In order to solve the above-mentioned conventional problems, the present inventor is provided on a side surface of a vertical prismatic furnace, and ejects a mixed flow of pulverized fuel and air. A burner nozzle, a pulverized fuel supply pipe connected to the burner nozzle to supply pulverized fuel and air, and a wind box forming a combustion auxiliary air supply path around the pulverized fuel supply pipe, In a pulverized fuel combustion device in which a vertical plane passing through an axis of a jet direction of the mixed flow is not orthogonal to a side surface of the furnace, a tip end opening surface of the burner nozzle is connected to a tip end of the pulverized fuel supply pipe and a combustion auxiliary air supply passage. the included formed asymmetrically with respect to the vertical plane, it proposes a pulverized fuel combustion apparatus, characterized in that the end opening surface of the burner nozzle was positioned in the side surface and the same plane of the furnace Is what you do. The pulverized fuel combustion device according to the present invention has the above-described structure, and the opening face of the tip of the burner nozzle is left and right with respect to the vertical plane including the tip of the pulverized fuel supply pipe and the tip of the combustion auxiliary air supply path. formed asymmetrically, and, since the end opening surface of the burner nozzle is positioned within the side surface and the same plane of said furnace, conveying air and combustion with pulverized fuel ejected from the distal end opening face of the burner nozzle The mixed flow of auxiliary air can form a flame on the furnace interior side relative to the furnace side surfaces and extensions or near these surfaces. Therefore, it is possible to prevent the flame from colliding with the furnace wall tube or licking the furnace wall tube. FIG. 1 is a horizontal sectional view showing a pulverized fuel combustion apparatus according to a first embodiment of the present invention. In the figure, (1) is a burner nozzle, (2) is a burner nozzle opening surface, (3) is a fine powder fuel supply pipe, (4) is a combustion auxiliary air supply path, (5) is a wind box, and (6) is Furnace wall tube, (7)
Indicates the sides of the furnace, respectively. The ejection direction axis (8) from which the pulverized fuel and the carrier air are ejected into the furnace is coaxial with the ejection direction axis from which the auxiliary combustion air is ejected into the furnace, and the vertical plane passing through these axes corresponds to the furnace. The side (7) is not perpendicular but inclined.
The shape of the burner nozzle (1) is different from the conventional one shown in FIG. 6 and is asymmetrical with respect to a vertical plane passing through the ejection direction axis (8). By adopting such a shape, the burner nozzle opening surface (2) can be located in the same plane as the furnace side surface (7),
The flame collides with the furnace wall tube (6) or licks the furnace wall tube (6) without having to arrange the furnace wall tube at an angle to the furnace side surface and facing the wind box side as in the related art. It can be burned without causing a phenomenon. FIG. 2 is a conceptual diagram (plan view) of a structure of a furnace wall tube (6) disposed around the pulverized fuel combustion device of the present embodiment, that is, a so-called burner panel structure. The figure above
7 , it can be seen that the present invention can significantly simplify the burner panel structure. FIG. 3 is a diagram schematically illustrating a flow state in the vicinity of the burner portion in the present embodiment. In this figure, (15) is a schematic view of a pulverized fuel supply pipe or a combustion auxiliary air supply path, (16) is a schematic view of a burner nozzle,
The arrow (17) indicates the axial velocity distribution of the pulverized fuel and carrier air or combustion auxiliary air into the furnace, and (18) indicates the furnace wall tube arranged toward the wind box side at an angle α with the furnace side surface. The schematic diagram and arrow (19) show schematic diagrams of the swirling flame in the furnace, respectively. The pulverized fuel combustion device of the present embodiment differs from the conventional burner in the basic flow characteristics near the burner. First, as shown in FIG. 3A, the burner nozzle opening surface (2) has an angle of β with respect to a plane perpendicular to the axis (8) of the direction in which the pulverized fuel and the carrier air are injected into the furnace. In the embodiment, in the burner nozzle wall surface (20) where the flow path of the jet of the pulverized fuel and the carrier air or the combustion auxiliary air is long, the opposite wall surface, that is, the flow path of the jet of the pulverized fuel and the carrier air or the combustion auxiliary air Since the pressure loss of the jet is larger than that of the burner nozzle wall (21) having a shorter length, the jet direction of the jet is actually deviated from the axis (8) toward the wall (21) as shown by an arrow (22). Deflect. The degree of the deflection depends on the angle β and the coefficient of frictional resistance of the inner surfaces of the wall surfaces (20) and (21). Further, as shown in FIG. 3 (b), in the conventional pulverized fuel combustion apparatus, the jet flow is influenced by the furnace wall tube (18) arranged toward the wind box side at an angle α with respect to the furnace side. Tended to deflect as shown by the axes (8) to (23), but in the present embodiment, the degree of deflection is different because the arrangement of the furnace wall tube is different from that of the furnace wall tube (18). Becomes smaller, and the jet becomes as shown by (24). As described above, in addition to the influence of the different flow pattern in the vicinity of the burner portion from the conventional pulverized fuel combustion device, the burner in the furnace finally influences the jet by the effect of the swirling flame (19) in the furnace. The jet direction of the jet (22) is actually at most 15 degrees to 20 degrees from the axis (8).
It is estimated to be deviated by degrees. FIG . 4 is a horizontal sectional view showing a pulverized fuel combustion device according to a second embodiment of the present invention. In the present embodiment, a swirler-type disperser (13) is provided on the bent portion (12) where the pulverized fuel supply pipe (3) is connected to the burner nozzle (1) or on the burner nozzle (1) side of the bent portion (12). This is an example of a pulverized fuel combustion device which is a pulverized fuel supply pipe (3) in which a core type concentration separator (14) is installed near a burner nozzle (1). In this figure, the mixed flow of the pulverized fuel and the carrier air flowing into the bent portion (12) from the direction of the arrow produces a density distribution due to the centrifugal force at the bent portion (12), and the concentration of the fine powder fuel Becomes thicker on the outer peripheral side of the bent portion (12) and conversely becomes thinner on the inner peripheral side. The density distribution is dispersed by the operation of the swirler type disperser (13) so that the distribution becomes uniform. Thereafter, the mixed stream having a uniform concentration is subjected to density separation by a core type density separator (14) so as to obtain an optimal combustion state, and is discharged into the furnace through the burner nozzle (1). FIG . 5 is a front view of a pulverized fuel combustion apparatus according to a third embodiment of the present invention as viewed from the inside of a furnace. In the present embodiment, the windbox are two pulverized fuel supply pipe (3) and five combustion auxiliary air supply passage (4) and a plurality of sets of units wind box consisting (two pairs in the illustrated example) and isolated from one another It is formed. In this figure, the burner nozzle opening surface (2)
Has a plurality of types of shapes such as a triangle, a rectangle, and a shape obtained by combining a semicircle and a straight line. According to the present invention, the following effects can be obtained. 1) The furnace wall tube and burner panel can be easily manufactured. 2) A furnace wall supporting structure having a simple structure at a low cost can be adopted. 3) Even in the case of a large-capacity burner or a large-capacity boiler, access to the periphery of the furnace wall can be facilitated, and maintenance performance can be improved. [0028] 4) the position of Bananozu Le can be placed in the furnace interior side than ever, it is possible to improve the maintainability.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a horizontal sectional view showing a pulverized fuel combustion device according to a first embodiment of the present invention. FIG. 2 is a structural conceptual view of a furnace wall tube according to the embodiment. FIG. 3 is a diagram schematically illustrating a flow state near a burner portion in the embodiment. FIG. 4 is a horizontal sectional view showing a pulverized fuel combustion device according to a second embodiment of the present invention. FIG. 5 is a front view showing a pulverized fuel combustion device according to a third embodiment of the present invention. FIG. 6 shows an example of a conventional pulverized fuel combustion device.
It is a horizontal sectional view . FIG. 7 relates to the above-mentioned conventional pulverized fuel combustion device .
It is a structure conceptual diagram of a furnace wall tube . [Description of Signs] (1) Burner nozzle (2) Burner nozzle opening surface (3) Fine powder fuel supply pipe (4) Auxiliary combustion air supply path (5) Wind box (6) Furnace wall pipe (7) Furnace side ( 8) pulverized fuel and injection direction axis of the conveying air (11) extending surface of the furnace side (12) pulverized fuel supply pipe bending portion (13) swirler type disperser (14) inner support ring shades separator (15) Schematic diagram of supply pipe for pulverized fuel or combustion auxiliary air (16) Schematic diagram of burner nozzle (17) Velocity distribution in jet direction (18) Schematic diagram of furnace wall tube arranged closer to wind box than furnace side surface (19) Schematic diagram of the swirling flame in the furnace (20) Burner nozzle wall surface on the side where the flow path length of the jet is long (21) Burner nozzle wall surface on the side where the flow path length of the jet is short (22) Jet direction of the deflected jet (23) Conventional Jet in the burner (24) Furnace wall tubes disposed in the windbox side at an angle of deflection jets (26) and furnace side α in the burner

Continued on the front page (72) Inventor Masashi Hishida 2-5-1 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Heavy Industries, Ltd. (72) Inventor Tomitsu Yokoyama 2-5-1 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Heavy Industries, Ltd. (72) Inventor Akiyasu Okamoto 5-717-1 Fukahori-cho, Nagasaki-shi, Nagasaki Laboratory, Mitsubishi Heavy Industries, Ltd. (56) References JP-A-57-164207 (JP, A) JP-A-6-341176 ( JP, A) JP-A-57-157913 (JP, A) JP-A-59-71005 (JP, U) JP-B 3-10841 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23C 5/08-5/32 F23D 1/00-1/06 F27D 17/00-23/04 C23C 11/00 F22B 31/00

Claims (1)

(57) [Claims 1] A burner nozzle provided on a side surface of a vertical prismatic furnace, and for ejecting a mixed flow of pulverized fuel and air;
A pulverized fuel supply pipe connected to the burner nozzle for supplying pulverized fuel and air; and a wind box forming a combustion auxiliary air supply path around the pulverized fuel supply pipe, and ejecting the mixed flow. In a pulverized fuel combustion device, a vertical plane passing through a direction axis is not orthogonal to the side surface of the furnace, the opening face of the tip of the burner nozzle is vertically extended including the tip of the pulverized fuel supply pipe and the tip of a combustion auxiliary air supply path. formed asymmetrically with respect to the plane, pulverized fuel combustion apparatus, characterized in that the end opening surface of the burner nozzle was positioned in the side surface and the same plane of the furnace.