JPS59173605A - Uniform feeding method of powder fuel in combustion furnace - Google Patents

Abstract

PURPOSE:To provide the uniform distribution of a rate of reduction of nitrogen oxide and the volume of non-combustibles in an entire furnace by a method wherein powder fuel is fed from a pair of fuel injection ports in such a way as injected fuel flows are struck against each other. CONSTITUTION:In a triple-stage combustion method in a box-like vertical furnace, a secondary fuel is fed from a pair of upper and lower lateral injection ports 6 and 7. The upper injection port 6 is arranged at a front wall 8 in such a way as it may face forwardly and downwardly in an inclined orientation and the lower injection port 7 is slightly inclined in a forwardly and upwardly directed condition. Thus, fuel injection flows 9 and 10 fed from these injection ports 6 and 7 are struck to each other to form a cresent-shaped injection flow layer 11. In this way, the secondary fuel is fed to a specified position under a uniformly distributed condition. With this arrangement, it is possible to make a uniform rate of reduction of nitrogen oxide and a uniform distribution of non-combustioned substance in an entire furnace.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for uniformly supplying powdered fuel to a combustion furnace.

In the three-stage combustion method in a box-shaped vertical furnace as shown in Figure 1, the primary fuel is combusted with primary air in excess of the stoichiometric amount.
A secondary combustion zone (1) is formed, and secondary fuel in excess of the amount required to consume the surplus of primary air is supplied to the upper side of the zone (1), that is, to the wake side, and the combustion is carried out under a reducing atmosphere. Slow combustion is performed to form a secondary combustion zone (2), and secondary air is further supplied to the upper side of the zone (2), that is, to the downstream side, to completely oxidize the unburned content of the secondary fuel. A tertiary combustion zone (3) is formed. In this case, if the secondary fuel supplied to form the secondary combustion zone (2) in the reduced state is not uniformly distributed in the furnace, the reduction rate of nitrogen oxides and the amount of unburned matter in the furnace will be affected. It makes a big difference. Therefore, it was necessary to supply the secondary fuel to the required positions in the furnace as evenly and dispersedly as possible, and to provide a large number of secondary fuel nozzles (5). The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a method for uniformly dispersing powdered fuel into a furnace by reducing the number of secondary fuel supply ports.

The method for uniformly supplying powdered fuel according to the present invention is characterized in that powdered fuel is supplied from a pair of fuel jets so that the fuel jets collide with each other to form a fan-shaped spouted layer in the furnace. That is.

The shape of the fuel supply port is a horizontally long rectangle, a circle, or an oval.

Hereinafter, the present invention will be specifically explained with reference to illustrated embodiments.

In the three-stage combustion method in a box vertical furnace, the secondary fuel is
As shown in Fig. 4-6, a pair of upper and lower horizontally rectangular ejection ports +6) (supplied from 71).
It is provided on the front wall (8) in a slightly inclined shape facing diagonally downward in the front direction, and the lower jet outlet (7) is provided in a shape slightly inclined in the forward direction diagonally upward direction. Therefore, the fuel jets +91 (10) coming out of these jet ports +61 +71 collide with each other to form a fan-shaped spout bed (11). In this way, the secondary fuel is uniformly distributed and supplied to the required locations within the furnace.

Although the above embodiment is a case of a three-stage combustion method in a box-shaped vertical furnace, the present invention is not limited thereto, and can also be applied to, for example, a drum-shaped horizontal furnace or a two-stage combustion method.

As described above, according to the present invention, powdered fuel is supplied from a pair of fuel jet ports so that the fuel jets collide with each other to form a fan-shaped spouted bed in the furnace, so that less fuel is consumed. Powdered fuel can be uniformly and dispersedly supplied into the furnace through the jetting ports, and as a result, in the multistage combustion method, the reduction rate of nitrogen oxides and the amount of unburned matter can be made uniform throughout the inside of the furnace.

[Brief explanation of the drawing]

Figure 1 is a vertical sectional view showing the 4-layer 4≠ox 3-stage combustion method in a conventional box-shaped vertical furnace, Figure 2 is a view from inside the furnace showing the conventional method, and Figure 3 is the middle of Figure 2. FIG. 4 is a cross-sectional view taken along line m-'m of FIG. 2, and FIG.
This figure and FIG. 6 are cross-sectional views taken along the V-V line and the Vl-■ line in FIG. 4, respectively. +6) (7j-... spout, (91(10)... jet, 11) "... spouted layer. , 4 people other than the above

Claims (1)

[Claims] A combustion furnace characterized by supplying powdered fuel from a pair of fuel jets so that the fuel jets collide with each other to form a fan-shaped jet layer in the furnace.・Uniformity of powdered fuel in the combustion furnace Supply method.