JPH0490412A - Pulverized coal distributor - Google Patents

Abstract

PURPOSE:To obtain pulverized coal having high concentration by forming forked connection ends to the inner circumferences and outer circumferences of bent pipes while being formed so as to be joined on their midways of the bent pipes and mutually connecting the forked connection ends of the inner circumferences and outer circumfernces of two bent pipes by two straight pipes. CONSTITUTION:Coal crushed by a coal breaker 3 is carried to a bent pipe 12 through a straight pipe 7, and separated in the directions of the arrows a1 and a2. The concentration of pulverized coal passing through the arrow a1 on the outer circumferential side of the bent pipe 12 is made higher by centrifugation and the concentration of the pulverized coal passing through the arrow a2 on the inner circumferential side of the bent pipe 12 is made lower at that time. These concentrated or thinned pulverized coal is carried separately by straight pipes 13, 13' and introduced into a bent pipe 12', and proceeds in the directions of the arrows a3, a4, a5. The degree of concentration is further promoted also by the same centrifugation in the bent pipe 12'. Accordingly, pulverized coal separated into high concentration and low concentration is carried to a furnace 2 and burnt, but the flame of concentrated pulverized coal functions as the flame assistant burner of a burner for thinned pulverized coal, thus stably burning the whole concentrated and thinned burners.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a pulverized coal distribution device applied to a pulverized coal-fired boiler, and more specifically relates to a pulverized coal distribution device designed to improve combustion efficiency. The figure is a perspective view showing the configuration of a conventionally used pulverized coal-fired boiler.

In FIG. 4, 1 is a pulverized coal-fired boiler having a furnace 2, and 3 is a coal crusher, which crushes coal (not shown) introduced from a coal input port 4. Further, 5 is a fan, which blows hot air heated by a heating device (not shown) to the coal crusher 3 through an air pipe 6. Further, 7a to 7e are straight pipes, 8a to 8e are vent pipes, 9 is a pulverized coal burner, and IO is a flame.

In the above configuration, the coal input from the coal input port 4 is crushed by the coal crusher 3, and heated by hot air blown through the fan 5 into the straight pipes 7 (7a to 7e) and the vent pipe 8.
(88 to 8e) and is transported by air flow along the path indicated by arrow a. The transported pulverized coal is then charged into the furnace 2 and burned by pulverized coal burners 9 provided at each corner of the furnace 2 of the pulverized coal-fired boiler 1.

Problems to be Solved by the Invention By the way, in these various types of pulverized coal-fired boilers, the ratio of coal to air is generally about 1:2 to 1:5, and especially when the boiler load is low and the amount of combustion coal is small, air The ratio of When the proportion of air in the pulverized coal injected from the burner 9 increases, the flame 10 ignites into the furnace 2, causing unstable combustion.

FIG. 5 is a sectional view showing a conventional technique that solves this problem of unstable combustion.

That is, conventionally, a pulverized coal separator t11 is provided inside the pulverized coal burner 9, and a pulverized coal air mixture with a high concentration and a pulverized coal air mixture with a low concentration are separated using centrifugal force separation or a cyclone. There is. As a result, the flame in the dense pulverized coal burner 9a becomes an auxiliary flame in the light pulverized coal burner 9b, resulting in stable combustion in the entire concentrated burner.

However, it is difficult to obtain a sufficiently high coal/air ratio using only the conventional pulverized coal separation device 11, and in order to obtain more effective centrifugal force separation or cyclone effect, it is necessary to increase the fluid pressure drop. There was a problem that it had to be done.

The present invention was made in order to solve the problems of the prior art, and an object of the present invention is to provide a pulverized coal distribution device that can obtain pulverized coal at a high concentration with a fluid pressure drop comparable to that of the conventional technology. shall be.

Means for Solving the Problems In order to solve the above problems, the present invention provides pulverized coal that has been pulverized by a coal pulverizer through at least two vent pipes and a straight pipe connecting these vent pipes. and a pulverized coal distribution device that air-flows the pulverized coal to a pulverized coal-fired boiler via a pulverized coal burner, wherein at least one end side of the vent pipe has a bifurcated connection port, and the bifurcated connection port is formed on the inner and outer peripheries of the vent pipe. The vent pipes are formed so as to merge in the middle of the vent pipes, and the bifurcated connection ports on the inner and outer circumferences of the two vent pipes are connected using two straight pipes.

Effect: According to the above means, the pulverized coal transported by air current is centrifuged when passing through the vent pipe, so that the concentration of pulverized coal contained in the air flow passing through the outer circumference is contained in the air flow passing through the inner circumference. The concentration is higher than that of pulverized coal. These airflows are then conveyed separately through straight pipes, and the degree of density becomes even stronger in the next-stage vent pipe.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing the main parts of a pulverized coal distribution device showing an embodiment of the present invention, FIG. It is a perspective view of the vent pipe formed in each bifurcated connection port.

First, in FIG. 2, the vent pipe 12 is bent almost at a right angle, with one end having a single large-diameter connection port 12a, and the other end having bifurcated connection ports 12b and 12c. It is formed on the circumferential side. The partition 12d between these bifurcated connection ports 12b and 12c is formed up to the middle of the bend pipe 12, so that the bifurcated connection ports 12b and 12c
and are merged in the middle of the vent pipe 12.

Next, in FIG. 3, both ends of a vent pipe 12' bent at a substantially right angle are formed into bifurcated connection ports 12b and 12c, respectively, and similarly to FIG. 2, these bifurcated connection ports 12b and 1
The partition 12d of 2c is formed up to the middle of the bend pipe 12', so that the bifurcated connection ports 12b' and 12c' are joined in the middle of the vent pipe 12'.

FIG. 1 shows the straight pipe 7 and the above-mentioned vent pipe 12.1.
2' and a straight pipe 13.13' are combined to form a pulverized coal distribution device. 13' connects the bifurcated inner peripheral connection ports 12c of the vent pipes 12 and 12', respectively.

According to the above configuration, the coal crushed by the coal crusher 3 (see FIG. 4) is conveyed to the vent pipe 12 via the straight pipe 7, and the coal is conveyed to the vent pipe 12 by the arrows a and a! separated in the direction of In this case, the concentration of pulverized coal is higher in the direction passing through the arrow a1 on the outer circumference side of the vent pipe 12 due to centrifugation, and the concentration in the direction passing through the arrow a on the inner circumference side of the vent pipe 12 is lower. These concentrated and light pulverized coals are conveyed separately by the straight pipes 13 and 13', enter the vent pipe 12', and advance in the direction of the arrow alv 84+a8. Here, too, the degree of shading is further promoted by similar centrifugation. The pulverized coal separated into high and low concentrations is transported to the furnace 2 (see Figures 4 and 5) and burned, or the flame of the dense pulverized coal becomes an auxiliary flame of the lighter pulverized coal burner. , the entire concentration burner burns stably.

In this embodiment, the number of vent pipes is two, but the degree of shading can be further increased by increasing the number of vent pipes.

Further, the shape of the vent pipe is not limited to the illustrated example, and various designs can be made.

Effects of the Invention As described above, according to the present invention, the connection port on at least one end side of the vent pipe in a pulverized coal distribution device applied to a pulverized coal-fired boiler is bifurcated, and the bifurcated connection port is connected to the inside of the vent pipe. The pulverized coal As it is transported through these, it is separated into high-concentration parts and low-concentration parts and reaches the furnace.As a result,
The ignition point of the burner is stabilized, and combustion with less unburned phosphorus can be achieved. In addition, even when the boiler is under low load, especially when the coal/air ratio is low, a highly concentrated pulverized coal solid fluid can be obtained, which stabilizes the combustion state and enables the boiler to operate at low load, resulting in energy savings. .

[Brief explanation of the drawing]

FIG. 1 is a perspective view of essential parts showing an example of a pulverized coal distribution device according to the present invention, FIGS. 2 and 3 are perspective views showing two vent pipes thereof, and FIG. 4 is a conventional pulverized coal distribution device. FIG. 5 is a perspective view showing the overall structure of the device, and FIG. 5 is a sectional view of a portion thereof. 1.Pulverized coal-fired boiler, 2.Furnace, 3.Coal crusher, 7.Straight pipe, 9.Pulverized coal burner, 1242'
...Bent pipe, 12b, 12c...Two-pronged connection port, 12
d...Partition, 13.13'...Straight pipe.

Claims (1)

[Claims] In a pulverized coal distribution device that airflow conveys pulverized coal pulverized by a coal crusher to a pulverized coal-fired boiler through at least two vent pipes, a straight pipe connecting these vent pipes, and a pulverized coal burner. , the connection port on at least one end side of the vent pipe is bifurcated, the bifurcated connection port is formed on the inner circumference and the outer circumference of the vent pipe, and is formed so as to join in the middle of the vent pipe, and the two vent pipes A pulverized coal distribution device characterized in that the inner and outer bifurcated connection ports are connected using two straight pipes.