JP2020176760A - Boiler device - Google Patents

Abstract

To provide a boiler device which can prevent the fletching wear of pipes, and is suitable for size reduction.SOLUTION: A boiler device 1 comprises: a furnace 2 for combusting fuel; a rear-part heat transfer part 3 arranged at an outlet side of the furnace 2; a sub-sidewall part 4 for connecting the furnace 2 and the rear-part heat transfer part 3; a suspension heat transfer pipe 6 suspended from a ceiling part 8 of the furnace 2; a traverse heat transfer pipe 5 arranged in the rear-part heat transfer part 3; and connecting pipes 7 for connecting the traverse heat transfer pipe 5 and the suspension heat transfer pipe 6. The connecting pipes 7 comprise: a plurality of protector pipes 11 arranged in a horizontal direction so as to traverse a space between groups of screen pipes 9 in the sub-sidewall part 4, and attached to opposing external peripheral faces of the connecting pipes 7 and the screen pipes 9; and a fastening tool 12 for fastening the connecting pipes 7 and the screen pipes 9 in a state that the plurality of protector pipes 11 are made to contact with one another.SELECTED DRAWING: Figure 3

Description

The present invention relates to a boiler device in which a group of heat transfer tubes such as a superheater and a reheater are arranged in a combustion gas passage.

In the boiler device, a fireplace that burns fuel is installed in the vertical direction, and a rear heat transfer part (also called a cage part) is installed on the rear side of the upper part of the fireplace via a sub-side wall part. .. The high-temperature combustion gas generated in the fireplace flows through the combustion gas passage in the order of the fireplace, the sub-side wall portion, and the rear heat transfer portion, and a heat exchanger for generating steam in the combustion gas passage. Is placed.

The heat exchanger arranged in the combustion gas passage is composed of a superheater, a reheater, an economizer and the like. The boiler water supply supplied from the water supply pump to the heat exchanger becomes saturated steam while being supplied to the water pipe of the furnace wall after being preheated by the economizer, and is heated by the combustion gas in the superheater. The superheated steam generated by the superheater is supplied to the high-pressure turbine and used for rotational driving, and the steam after rotational driving is supplied to the reheater. Here, the reheater is composed of a primary reheater (low temperature reheater) and a secondary reheater (high temperature reheater), and the steam discharged from the high pressure turbine is combined with the primary reheater. After being reheated by the secondary reheater, it is supplied to the low-pressure turbine and driven to rotate. For example, the primary reheater is composed of a horizontal heat transfer tube supported horizontally on the side wall of the rear heat transfer section, and the secondary reheater is suspended from the ceiling on the front side of the secondary side wall. It is composed of heat transfer tubes.

In this type of boiler device, a ceiling chamber called a penthouse is provided in the ceiling of the fireplace and the combustion gas passage, and the upper part of the heat transfer tube group constituting the suspended heat exchanger is connected in the penthouse. A plurality of pipes and a manifold connecting these pipes are arranged. Conventionally, in a reheater composed of a primary reheater and a secondary reheater, a plurality of connecting pipes connected to the horizontal heat transfer tubes of the primary reheater are extended upward to reach the inside of the penthouse. These connecting pipes and a group of suspended heat transfer tubes of the secondary reheater penetrating the ceiling portion are connected in the penthouse via pipes or manifolds (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2012-193939

In the boiler device described in Patent Document 1, a group of connecting pipes connected to the horizontal heat transfer tube of the primary reheater is extended upward to penetrate the ceiling portion, and then the secondary reheater is passed through the inside of the penthouse. Since it is connected to the suspended heat transfer tube group, a large space is required for arranging the connecting tube group on the outlet side of the secondary side wall, which is a major factor hindering the miniaturization of the boiler device. Was there. Therefore, it is conceivable to extend the connecting pipe group horizontally in the direction of the sub-side wall without guiding it to the penthouse, and connect these connecting pipe groups to the suspended heat transfer tube group of the secondary reheater across the sub-side wall. However, in that case, if the screen pipe group and the connecting pipe group constituting the sub-side wall portion are arranged close to each other and intersect at a right angle, the screen pipe and the connecting pipe that swing in response to the gas flow rub against each other. There is a concern that fretting wear (surface damage) will occur.

The present invention has been made from the actual situation of such a prior art, and an object of the present invention is to provide a boiler device capable of preventing fretting wear between pipes and suitable for miniaturization.

In order to achieve the above object, a typical present invention includes a furnace, a rear heat transfer section provided on the outlet side of the furnace, a sub-side wall portion connecting the furnace and the rear heat transfer section, and the above. A suspended heat transfer tube suspended from the ceiling of the furnace, a horizontal heat transfer tube installed inside the rear heat transfer section, and a plurality of connecting tubes connecting the suspended heat transfer tube and the horizontal heat transfer tube. In a boiler device in which a plurality of screen pipes extending in the vertical direction are arranged at least in the left-right direction on the sub-side wall portion, the plurality of connecting pipes intersect with the plurality of screen pipes. A state in which a plurality of protector pipes arranged horizontally in the sub-side wall portion and mounted on the outer peripheral surfaces of the adjacent connecting pipes and the screen pipes facing each other are brought into contact with each other. It is characterized in that the connecting pipe and the fastener for fastening the screen pipe are provided.

According to the present invention, it is possible to prevent fretting wear between pipes and to reduce the size of the boiler device. Issues, configurations and effects other than those described above will be clarified by the description of the embodiments described below.

It is a block diagram which shows the main part of the boiler apparatus which concerns on embodiment of this invention. It is a detailed view of part A of FIG. It is a detailed view of part B of FIG. It is a detailed view of the part B of FIG. 2 seen from above. It is a perspective view of the protector tube provided in the boiler device which concerns on embodiment. It is a perspective view of the fastener provided in the boiler device which concerns on embodiment.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 6. FIG. 1 is a configuration diagram showing a main part of a boiler device according to an embodiment. In the present specification, unless otherwise specified, the left-right direction of FIG. 1 is the front-rear direction of the boiler device, and the direction orthogonal to the paper surface of FIG. 1 is the left-right direction of the boiler device.

As shown in FIG. 1, the boiler device 1 includes a fireplace 2 for burning fuel, a rear heat transfer unit 3 provided on the outlet side (rear side) of the fireplace 2, a fireplace 2 and a rear heat transfer unit 3. It is provided with a sub-side wall portion 4 for connecting. The combustion gas generated in the furnace 2 circulates in the combustion gas passage, which is a gas flow path, in the order of the fireplace 2, the sub-side wall portion 4, and the rear heat transfer portion 3, and is finally discharged to the outside through an exhaust gas duct (not shown). To. In the combustion gas passage, in addition to the primary reheater 5 and the secondary reheater 6 constituting the reheater, heat exchangers such as a superheater and an economizer (not shown) are arranged in the furnace. Heat exchange is performed between the combustion gas generated in 2 and the boiler water supply flowing through these heat exchangers. Then, the steam introduced into the primary reheater 5 from a high-pressure turbine (not shown) is superheated by the primary reheater 5, then introduced into the secondary reheater 6, and rises to a predetermined temperature by the secondary reheater 6. After being heated, it is discharged from the outlet side of the secondary reheater 6 and supplied to a low-pressure turbine (not shown).

The primary reheater 5 is composed of a plurality of horizontal heat transfer tubes supported by a peripheral wall (cage wall) of the rear heat transfer unit 3, and as will be described later, a plurality of horizontal heat transfer tubes connected to these horizontal heat transfer tubes. The primary reheater 5 and the secondary reheater 6 are connected via a connecting pipe 7. The secondary reheater 6 is composed of a plurality of suspended heat transfer tubes suspended from the ceiling portion 8 of the fireplace 2, and the secondary reheater 6 and superheater are contained in the penthouse above the ceiling portion 8. A plurality of pipes to which the upper parts of the suspended heat transfer tubes constituting the vessel are connected, a manifold to which these pipes are connected, and the like are arranged.

2 is a detailed view of part A of FIG. 1, FIG. 3 is a detailed view of part B of FIG. 2, and FIG. 4 is a detailed view of part B of FIG. 2 as viewed from above. As shown in FIGS. 2 to 4, a plurality of screen tubes 9 extending in the vertical direction are arranged in the left-right direction and the front-rear direction at the outlet of the sub-side wall portion 4 (the inlet of the rear heat transfer portion 3). A plurality of cage front wall tubes 10 are arranged behind the tubes 9 in the left-right direction and the front-rear direction. The cage front wall tube 10 constitutes the cage front wall of the rear heat transfer section 3, and the diameter of the cage front wall tube 10 is smaller than that of the screen tube 9. The plurality of connecting pipes 7 connected to the horizontal heat transfer tubes of the primary reheater 5 horizontally cross the screen tube 9 and the cage front wall tube 10 to suspend the secondary reheater 6. It is connected to a heat pipe. Therefore, the connecting pipe 7 extending in the horizontal direction, the screen pipe 9 extending in the vertical direction, and the cage front wall pipe 10 intersect at right angles, and the connecting pipe 7 and the screen pipe 9 on the large diameter side are arranged close to each other. Fretting wear may occur due to the contact between the connecting pipe 7 and the screen pipe 9. In the present embodiment, in order to prevent such fretting wear, the protector pipes 11 are attached to the outer peripheral surfaces of the connecting pipe 7 and the screen pipe 9 facing each other, and the protector pipes 11 are in contact with each other. The connecting pipe 7 and the screen pipe 9 are fastened (restrained / fixed) by the frame-shaped fastener 12.

Specifically, as shown in FIG. 5, the protector pipe 11 is a half-split pipe obtained by bending a stainless steel plate (metal plate) having a thickness of about 3 mm into a semi-cylindrical shape, and such a protector pipe 11 is a connecting pipe 7. Is attached to the outer peripheral surfaces of the screen tube 9 and the cage front wall tube 10, respectively. Here, the protector pipe 11 is attached to the connecting pipe 7 so as to cover the half peripheral surface of the connecting pipe 7 facing the screen pipe 9 and the cage front wall pipe 10, and the protector pipe 11 is a flow of combustion gas. Only the end located on the upstream side in the direction (see the arrow in FIG. 3) is welded and fixed, and the other parts are unwelded free ends. Further, the protector tube 11 is attached to the screen tube 9 so as to cover almost the entire circumference of the screen tube 9 with a pair of protector tubes 11, and these protector tubes 11 are welded and fixed only at the upper end portion, and other than that. The part of is a free end that is not welded. Since the diameter (φ50.8) of the cage front wall tube 10 is sufficiently smaller than the diameter of the screen tube 9 (φ63.5), it is unlikely that the connecting tube 7 and the cage front wall tube 10 rub against each other. A protector pipe 11 is welded and fixed to the outer peripheral surface of the cage front wall pipe 10 in the same manner as the screen pipe 9.

As shown in FIG. 6, the fastener 12 is composed of a pair of metal rods made of stainless steel bent in a U shape, and is integrated into a frame shape by welding both ends of these metal rods. In the present embodiment, as shown in FIGS. 3 and 4, two screen pipes 9 and two cage front wall pipes 10 extending in the vertical direction, and a total of four screen pipes 9 and cage front wall pipes 10 are used. A group of pipes (10 in total) consisting of a total of 6 connecting pipes 7 arranged in 3 stages in the vertical direction, which are arranged close to each other on the left and right sides, is regarded as one binding unit, and the pipe group is divided into each binding unit. It is restrained and fixed by tying it diagonally with a fastener 12. However, the number of connecting pipes 7 serving as one unit of binding is not limited to this. It can also be a unit. Further, the number of the screen tube 9 and the cage front wall tube 10 can be arbitrary.

The protector pipes 11 are attached to the outer peripheral surfaces of the connecting pipes 7 and the screen pipes 9 intersecting each other at right angles in this way, and the connecting pipes 7 and the screen pipes 9 are fastened in a state where the protector pipes 11 are in contact with each other. When restrained and fixed by the tool 12, the connecting pipe 7 and the screen pipe 9 are prevented from swinging independently, so that fretting wear of the connecting pipe 7 and the screen pipe 9 can be prevented. The cage front wall tube 10 having a smaller diameter than the screen tube 9 has a gap between it and the connecting tube 7 to avoid contact, but the cage front wall tube 10 also has a protector tube 11. Since it is attached, even if the connecting pipe 7 and the protector pipe 11 attached to the cage front wall pipe 10 rub against each other, fletting wear does not occur on the pipe surfaces of the connecting pipe 7 and the cage front wall pipe 10. It has become.

As described above, in the boiler device 1 according to the present embodiment, the horizontal heat transfer tubes of the primary reheater 5 installed in the rear heat transfer section 3 are placed between the screen tubes 9 groups in the sub-side wall portion 4. It is necessary to route the connecting pipe 7 because it is connected to the suspended heat transfer pipe of the secondary reheater 6 suspended from the ceiling 8 of the furnace 2 via the connecting pipe 7 extending in the horizontal direction across the furnace. Space can be reduced, and a compact boiler device 1 can be realized accordingly. Then, the connecting pipes 7 and the screen pipes 9 are arranged close to each other and intersected at a right angle, and the protector pipes 11 are attached to the outer peripheral surfaces of the connecting pipes 7 and the screen pipes 9 facing each other, and the protector pipes of each other are attached. Since the entire pipe group of the plurality of connecting pipes 7 and the screen pipe 9 is restrained and fixed by the fastener 12 in a state where the 11 pipes are in contact with each other, the independent swing of each pipe is eliminated and the rocking is eliminated. It is possible to prevent the fretting wear of the heat transfer tube body due to the movement.

Further, in the boiler device 1 according to the present embodiment, a half-split pipe in which the metal loss plate is curved into a semi-cylindrical shape is used as the protector pipe 11, and the outer peripheral surface of the screen pipe 9 extending the protector pipe 11 in the vertical direction. Since only the upper end of the protector tube 11 is welded and fixed and the other parts are not welded to the free end, the screen tube 9 and the protector tube 11 having different thermal expansion coefficients can tolerate thermal expansion and contraction. At the same time, it is possible to prevent the ash in the combustion gas from accumulating between the screen pipe 9 and the protector pipe 11. Further, when the protector pipe 11 is attached to the outer peripheral surface of the connecting pipe 7 extending in the horizontally direction, only the end portion of the protector pipe 11 located on the upstream side in the flow direction of the combustion gas is welded and fixed, and the other parts are welded and fixed. Since the free end is not welded, thermal expansion and contraction of the connecting pipe 7 and the protector pipe 11 having different thermal expansion coefficients can be tolerated, and ash in the combustion gas accumulates between the connecting pipe 7 and the protector pipe 11. Can be prevented.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention, and all the technical matters included in the technical idea described in the claims are all. It is the subject of the present invention. Although the above-described embodiment shows a suitable example, those skilled in the art can realize various alternative examples, modified examples, modified examples or improved examples from the contents disclosed in the present specification. These are included in the technical scope described in the appended claims.

For example, in the above embodiment, the fastener 12 is used in which the ends of two metal rods bent in a U shape are welded to each other, but a plurality of connecting pipes 7 and a screen are arranged so as to be cross-arranged. Other fasteners such as strings can be used as long as the entire tube group of the tube 9 can be restrained and fixed.

1 Boiler device 2 Fireplace 3 Rear heat transfer part 4 Sub-side wall part 5 Primary reheater (horizontal heat transfer tube)
6 Secondary reheater (hanging heat transfer tube)
7 Connecting pipe 8 Ceiling part 9 Screen pipe 10 Cage front wall pipe 11 Protector pipe 12 Fastener

Claims (4)

A furnace, a rear heat transfer section provided on the outlet side of the furnace, a sub-side wall section connecting the furnace and the rear heat transfer section, and a suspended heat transfer tube suspended from the ceiling of the furnace. A horizontal heat transfer tube installed inside the rear heat transfer section and a plurality of connecting tubes for connecting the suspended heat transfer tube and the horizontal heat transfer tube are provided, and the sub-side wall portion extends in the vertical direction. In a boiler device in which a plurality of screen tubes are arranged at least in the left-right direction.
The plurality of connecting pipes are arranged horizontally in the sub-side wall portion so as to intersect with the plurality of screen pipes.
A plurality of protector pipes mounted on the outer peripheral surfaces of the adjacent connecting pipes and the screen pipes facing each other, and
A boiler device including a fastener for fastening the connecting pipe and the screen pipe in a state where the plurality of protector pipes are in contact with each other. In the boiler device according to claim 1,
A boiler device characterized in that the protector tube is made of a metal plate curved in a semi-cylindrical shape. In the boiler device according to claim 1 or 2.
Only the upper end of the protector pipe is fixed to the screen pipe, and only the end of the protector pipe located upstream with respect to the flow direction of the combustion gas flowing through the furnace is fixed to the connecting pipe. A boiler device characterized by being In the boiler device according to claim 1,
The fastener is a boiler device including a pair of metal rods that bend in a U shape, and the ends of the pair of metal rods are integrated by welding to form a frame shape.

Images