JPS60147001A - Abrasion preventive structure of circumferential wall pipe of fluidized bed boiler - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure for preventing wear of peripheral tubes of a fluidized bed boiler using coal, petroleum coke, etc. as fuel.

FIG. 1 shows the structure of a fluidized bed boiler, and an outline of the conventional wear prevention structure will be explained.

In Fig. 1, numeral 1 denotes the peripheral wall tube of the boiler, 2 denotes the lower header, 3 denotes the upper header, 4 denotes the drum that separates the brackish water mixture into water and steam S, and 5 connects the drum and the lower header 2. Piping, 7 is an air duct that guides combustion air, 8 is combustion air, 9 is a wind chamber, 1° is a partition wall made up of a part of the surrounding wall tube 1, 11 is an air nozzle, 12 is a fuel for the boiler 13 is a fuel inlet, 14 is a fluidized medium such as sand or limestone, 15 is an inlet for the fluidized medium 14, 16 is a fluidized bed, 1
7 is the height of the fluidized bed 16, and 18 is a temperature increasing burner at startup.

In the fluidized bed boiler, a fluidized medium 14 such as sand or limestone is introduced onto the partition wall 10, a heating burner 18 is ignited,
Air 8 from the air duct 7 is heated and sent as hot air to the wind chamber 9 and blown up from the air nozzle 11 to flow the fluidizing medium 14°.

Next, the fuel 13 is introduced from the fuel inlet 12, and the fluidized bed 1
6 to maintain combustion. When normal operation starts, the temperature increasing burner 18 is extinguished, and the amount of combustion air 8 sent from the air duct 7 is controlled to stably operate fluidized combustion.

On the other hand, the heat generated by this combustion is absorbed by the peripheral wall pipe 1 and transported to the header 3, the connecting pipe 6, and the drum 4 in order, causing brackish water separation in the drum 4, and the water passes through the connecting pipe 5 to the lower pipe. It is distributed to the peripheral wall tube 1 from the gathering 2.

In this way, in the fluidized bed boiler, the chamber forming the fluidized bed 16 is composed of the peripheral wall tube 1, so that the fluidized bed 16 is
It is known that the movement of the tube 4 causes wear on the peripheral wall tube 1.

For this reason, countermeasures have been taken, such as using expensive materials with excellent wear resistance for the surrounding wall tube or covering the surrounding wall tube in the wear area with metal or non-ferrous materials. This method inhibits heat absorption in the surrounding wall tubes and reduces the functionality of the fluidized bed boiler.

Conventionally, the above-mentioned problems occur, so it is necessary to take measures against severe wear that inhibits heat absorption.The present invention is proposed as a countermeasure to this problem.In a fluidized bed boiler, the height of the fluidized bed is
7 is almost constant, and the height at which wear occurs is limited to the upper limit of the height 17 of the fluidized bed, and the fluidized medium 14 is in a downward flow on the surface of the peripheral wall tube 10. , focused on the fact that wear occurs due to the flow of the fluid medium in one direction, and installed a simple baffle to reduce the surface velocity so that the flow of the fluid medium 14 does not come into direct contact with the peripheral wall tube. The novel feature of the present invention is that it prevents heat absorption and does not inhibit heat absorption of the peripheral wall tube.

Hereinafter, embodiments of the present invention will be described in detail with reference to FIG. 2 and subsequent figures.

FIG. 2 shows the construction of an anti-wear baffle placed in the fluidized bed 16 of the present invention. Code 1.2.9.10.11.
14, 16, and 17 are the same as those explained in FIG. 1 above.

This is a simple configuration in which an anti-wear buckle 19 is installed in the fluidized bed 16 by directly welding to the peripheral wall tube 1 or supported by a support base attached to the peripheral wall tube 1.

Figures 3 (al and bl) show the wear status of the peripheral wall tube 1. Also, Figure 4 (aL (b) shows the flow status of the fluidizing medium 14 when a wear prevention baffle] 9 is provided. Suhiko Well,
In a fluidized bed boiler, the air 8 ejected from the air nozzle 11 at the bottom of the bed suspends the fluidized medium 14. Air bubbles rise together with the fluidized medium 4, and to compensate for this, the fluidized medium 14 flows downward along the wall surface. occurs. Therefore, the flow of the fluid medium 14 directly contacts the surface of the peripheral wall tube 1, causing wear.

As shown in FIG. 4 (al, (1)), by providing an anti-wear baffle 19 on the peripheral wall tube 1, the flow of the fluid medium 14 is not brought into direct contact with the peripheral wall tube 1, and the tube surface velocity of the fluid medium 14 is reduced. This can prevent wear. In addition, by making this shape, the peripheral wall tube 1
There is no need to cover the entire surface, and heat transfer is likely to be inhibited.

Although FIG. 2 shows an example in which five stages of abrasion prevention baffles 19 are provided, the number of stages can be arbitrarily selected for each unit according to the height 17 of the fluidized bed, and the number of stages can be arbitrarily selected for each unit, and By limiting the height, the movement of the entire fluidized bed 16 can be changed and wear of the peripheral wall tube 1 can be prevented.

5 to 8 show specific examples of attachment according to the present invention.

FIGS. 5a) and 5b show an example in which the anti-wear baffle 19 is attached to the peripheral wall tube 1 by direct welding.

FIGS. 6a) and (1)) show an example in which the support base 20 is welded to the peripheral wall W1, and the anti-wear baffle 19 is attached thereon by a pole 21.

In this case, since there is a difference in thermal expansion between the wear prevention baffle 19 and the peripheral wall tube 1, it is necessary to divide the wear prevention baffle 19 into appropriate lengths as shown in FIG.

Fig. 8 (fat, fb) shows an example in which the abrasion prevention baffle 19 is molded with a fire-resistant coating material, and Fig. 9 (fat, fb)
L (bl shows an example in which block-shaped refractory bricks are attached by supporting hardware 22.

According to the circumferential tube wear prevention structure of the present invention, since the flow of the fluid medium does not come into direct contact with the circumferential tube surface, there is a great effect that wear can be prevented without inhibiting heat absorption of the circumferential tube.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the structure of a fluidized bed boiler, Fig. 2 and subsequent figures relate to the present invention, Fig. 2 is a cross-sectional view showing a fluidized bed provided with a wear-preventing ballad; A sectional view showing the wear condition, Fig. 3 (bl is a sectional view taken along the line A-A of Fig. 3 (al), Fig. 4 ia) is a sectional view showing that the flow of the fluid medium is not brought into direct contact with the flow, Fig. 4 Figure (b) is a sectional view taken along line B and -B of Figure 4 (al), Figures 5 through 8 show installation examples of the present invention, and Figure 5 + al shows the baffle directly attached to the surrounding wall tube. A side view of the welded example, Fig. 5 (bl is a cross-sectional view taken along the line C-C of Fig. 5 (al), Fig. 6 fal is a side view of an example in which the baffle is attached with bolts, Fig. 6 (bl is Figure 6 (
8 (1)) is a cross-sectional view taken along the line D=D of al, a side view of the first example, and a cross-sectional view taken along the line E-E in FIG.
Figure fa) is a side view of an example with refractory bricks installed, and Figure 9 (
bl is a sectional view taken along line FF in FIG. 9(a). 1...Surrounding wall pipe, 8...Combustion air, 10...Partition wall, 1
4.Fluidized medium, 16.Fluidized bed, 17.Height of fluidized bed, 19.Abrasion prevention baffle, 201.Support stand, 21
・φ bolt, 22...Support hardware. (7) Figure j Figure 5 Figure 6 (0,) and 0-) c b,) (ri Figure 7) Figure 6 Figure 9 (Q,) (Q) (1) (b)

Claims (1)

[Claims] Prevention of wear on peripheral wall tubes of a fluidized bed boiler, characterized in that the peripheral wall tubes are provided with abrasion prevention baffles in the form of single or multiple horizontal shelves that reduce the velocity of the fluidized medium on the surface of the peripheral wall tubes. structure.