JP2024032219A - boiler - Google Patents

Abstract

An object of the present invention is to provide a boiler that can maintain the performance of the boiler. [Solution] A boiler including a plurality of water pipes connecting an upper header and a lower header in a combustion chamber, the exhaust port leading out exhaust gas from the combustion chamber, and connecting the upper header and the lower header outside the combustion chamber. and a communication pipe that communicates with the exhaust port, and the communication pipe is provided on the exhaust port side. [Selection diagram] Figure 2

Description

The present invention relates to a boiler.

As disclosed in Patent Document 1, a steam boiler is known that includes a plurality of water pipes that connect an upper header and a lower header in a combustion chamber, and an exhaust port that discharges exhaust gas. In such a boiler, water supplied from a lower header is heated in a water pipe, and canned water that is pushed up along with steam to an upper header via a downcomer pipe is circulated to the lower header.

Japanese Patent Application Publication No. 2003-56803

In a boiler, exhaust gas is generally discharged from the exhaust port, so the closer a water pipe is to the exhaust port, the higher the amount of heat received per unit area of the water pipe (hereinafter also referred to as heat load). For this reason, the water pushed up from the water pipes to the upper header together with steam tends to flow into the water pipes that are farther away from the exhaust port and have a lower heat load than to the water pipes that are closer to the exhaust port and have a higher heat load. Under such circumstances, in the boiler described in Patent Document 1, the downcomer pipe is provided on the side opposite to the exhaust port and on the side where the heat load is low. For this reason, water can be circulated through the upper header and downcomer pipes in water pipes that are far away from the exhaust port and have a low heat load, whereas water circulation is poor in water pipes that are close to the exhaust port. As a result, the closer the water pipe is to the exhaust port and the worse the circulation, the more likely it is to corrode, which may reduce the performance of the boiler (for example, the durability and heat conductivity of the water pipe).

The present invention was devised in view of such circumstances, and provides a boiler that can maintain the performance of the boiler.

In order to achieve the above object, a boiler according to an aspect of the present invention is a boiler including a plurality of water pipes connecting an upper header and a lower header in a combustion chamber, the boiler including an exhaust port for leading out exhaust gas from the combustion chamber. , a communication pipe that communicates the upper header and the lower header outside the combustion chamber, and the communication pipe is provided on the exhaust port side.

According to the above configuration, the communication pipe that communicates the upper header and the lower header is provided on the exhaust port side where the heat load is high. As a result, canned water in the water pipes near the exhaust port and subject to a high heat load can be easily circulated through the communication pipe, and local corrosion can be suppressed by suppressing imbalance in the amount of circulation between the plurality of water pipes. As a result, the durability of the boiler can be improved.

Preferably, the lower header is provided with a water supply port, and the water supply port is provided on a side opposite to the exhaust port.

According to the above configuration, the water supply port is provided on the side opposite to the exhaust port where the heat load is low. As a result, compared to the case where the water supply port is provided on the exhaust port side, scale adhesion to the water pipes near the water supply port can be suppressed, and scale can be prevented from adhering unevenly between multiple water pipes. It can be suppressed. As a result, the heat transfer performance of the boiler can be maintained.

Preferably, the communication pipe includes a steam separator.

According to the above configuration, since the communication pipe can also be used as a pipe for connecting the steam/water separator, it is possible to prevent an increase in the number of parts.

FIG. 2 is a diagram for explaining a vertical cross-sectional view of a boiler in the present invention. FIG. 2 is a schematic cross-sectional view of the boiler taken along the Z-Z line in FIG. 1 when viewed from above. It is a longitudinal cross-sectional view which shows an example of another embodiment of the boiler in this invention.

Below, a schematic configuration of a boiler 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. It should be noted that the present invention is not limited to these examples, but is indicated by the scope of the claims, and it is intended that all changes within the meaning and range equivalent to the scope of the claims are included in the present invention. Ru.

FIG. 1 shows a can body 2, which is included in a boiler 1 and which burns fuel to generate steam. The can body 2 is formed into a substantially cylindrical shape, and includes therein a burner 3 for burning fuel, a plurality of water pipes 9 (9a, 9b), an upper header 7, a lower header 8, and the like. The plurality of water pipes 9 are connected between the upper header 7 and the lower header 8, respectively. Note that although an example in which the fuel is a gas such as gas will be described, the fuel is not limited to gas, and may be a liquid such as oil.

As shown in FIG. 2, the plurality of water pipes 9 are annularly housed inside the can body 2, and include inner water pipes 9a that are erected at predetermined intervals in the circumferential direction of the can body 2; It includes outer water pipes 9b that are erected at predetermined intervals in the circumferential direction of the can body 2 on the outside of the water pipes 9a. These inner water pipes 9a and outer water pipes 9b are also collectively referred to as water pipes 9. As shown in FIG. 1, an inner vertical fin 9a' is provided in a gap between adjacent water tubes among the inner water tubes 9a, leaving a gap at the lower end so as to close the gap. Regarding the outer water tubes 9b, outer vertical fins 9b' are provided in the gaps between adjacent water tubes, leaving a gap at the upper end so as to close the gaps. As a result, a combustion chamber 4 and a combustion gas passage 5 are formed approximately in the center of the can body 2. The exhaust gas that has passed through the combustion gas passage 5 is led out from the exhaust port 15 to the exhaust duct 11 and discharged to the outside of the can body 2 .

Burner 3 is provided above combustion chamber 4 . The burner 3 heats canned water introduced into the plurality of water pipes 9 to generate steam. Further, the burner 3 is supplied with combustion air from an air supply device and fuel gas from a fuel supply device. The air supply device includes a blower, and the fuel supply device includes a flow rate regulating valve. The combustion amount of the boiler 1 is adjusted continuously or in stages by controlling the blower and flow rate adjustment valve in a manner according to the combustion state (combustion amount) by a control device that controls the operation and operation of the boiler 1. be done. For example, when the combustion state is a high combustion state, the opening degree of the flow rate regulating valve is controlled to 100%, and when the combustion state is a low combustion state, where the combustion amount is smaller than the high combustion state, the opening degree of the flow rate regulating valve is controlled to 50%. controlled by.

The lower header 8 is provided at the lower part of the can body 2 and is connected to the lower parts of the plurality of water pipes 9. The lower header 8 is connected to a water supply pipe 10 that supplies water to the can body 2. A water supply pump and a check valve (both not shown) are provided on the upstream side of the water supply pipe 10. Water sent from the water supply pump via the water supply pipe 10 is supplied to the lower header 8 from the water supply port 14. The supplied water is heated in the water pipe 9.

The upper header 7 is provided at the upper part of the can body 2 and is connected to the upper parts of the plurality of water pipes 9. The upper header 7 has a function of collecting steam generated in the plurality of water pipes 9 and water pushed up together with the steam, and separating it into dry steam and moisture (steam-water separation). The dry steam separated in the upper header 7 is sent out to predetermined equipment via the steam supply pipe 6. On the other hand, the moisture separated in the upper header 7 is returned to the lower header 8 via the downcomer pipe 12 that communicates the upper header 7 and the lower header 8. As a result, canned water is further circulated in addition to the circulation performed within the upper header 7, which will be described later. Note that a blow pipe 13 for discharging can water from the can body 2 is connected to the downcomer pipe 12 in the middle. The blow pipe 13 is provided with a blow valve 13a. By opening the blow valve 13a, the can water in the can body 2 can be discharged (blow).

Combustion gas resulting from combustion of fuel in the combustion chamber 4 is led out to the combustion gas passage 5 between the inner water pipe 9a and the outer water pipe 9b, as shown by the dotted arrow in FIG. Then, the combustion gas passes outside the outer water pipe 9b and is led out as exhaust gas from the exhaust port 15 to the exhaust duct 11. At this time, the combustion gas exchanges heat with the water in the plurality of water pipes 9, and the water in the plurality of water pipes 9 is heated. Thereby, the water heated in the plurality of water pipes 9 turns into steam, which is supplied from the upper header 7 via the steam supply pipe 6 to various devices that use steam.

In the boiler 1 having the above-described can body structure, combustion gas is discharged from the exhaust port 15 provided at one location, so combustion is performed so that the combustion gas is biased toward the exhaust port 15. It passes through the gas passage 5. Therefore, the closer the water tube is to the exhaust port 15, the more the water tube comes into contact with the combustion gas, resulting in a higher heat load, and the farther the water tube is from the exhaust port 15, the lower the heat load. The problem caused by uneven heat load on the water pipes depending on the positional relationship with the exhaust port 15 will be described with reference to FIG. 2.

In FIG. 2, for convenience of explanation, the axis passing through the center (center) of the can body 2 and the center position in the width direction (horizontal direction) of the exhaust port 15 is defined as the Y axis, and the axis perpendicular to the Y axis The axis passing through the center of the body 2 is shown as the X axis. In the following description, the exhaust port 15 side refers to the side where the exhaust port 15 is included (the side along the X axis of the can body 2 in FIG. 2) when the can body 2 is divided along the The side opposite to the exhaust port 15 is the side that does not include the exhaust port 15 when the can body 2 is divided along the X-axis (the side opposite to the X-axis of the can body 2 in FIG. 2). lower half side).

As described above, in the boiler 1 of this embodiment, the closer the water pipes are to the exhaust port 15, the higher the heat load becomes, and the farther away from the exhaust port 15 the water pipes are, the lower the heat load becomes. Therefore, when roughly classified on the X axis in FIG. 2, the water pipe on the exhaust port 15 side has a higher heat load than the water pipe on the opposite side to the exhaust port 15.

In addition, in water pipes with a high heat load, a large amount of steam is generated, and the steam is sent vigorously to the upper header 7, and water is also pushed up. On the other hand, in water pipes with a low heat load, steam generation is slow and the momentum toward the upper header 7 is weak. Therefore, the water pushed up to the upper header 7 is more likely to flow into water pipes with a low heat load that are further away from the exhaust port 15, where the amount of steam generated is small and has no momentum, than into water pipes with a high heat load near the exhaust port 15. Become. Roughly classified on the X axis in FIG. 2, the water pushed up by the upper header 7 flows more easily into the water pipe on the opposite side of the exhaust port 15 than into the water pipe on the side of the exhaust port 15. As a result, canned water in the water tube on the opposite side to the exhaust port 15 can be circulated through the upper header 7, whereas water circulation in the water tube on the side of the exhaust port 15 becomes poor. As a result, the water circulation (water quality) within the can body 2 becomes uneven, and the closer the water pipe is to the exhaust port 15 and the worse the circulation, the less concentrated (lower pH) the can water becomes, making it more likely to corrode unless other measures are taken. (local corrosion), which could reduce the durability of the water pipe.

Therefore, in the boiler 1 in this embodiment, the downcomer pipe 12 as a communication pipe that communicates the upper header 7 and the lower header 8 is provided on the exhaust port 15 side where the heat load is high in the can body. That is, the downcomer pipe 12 was connected at a predetermined position on the exhaust port 15 side of each of the upper header 7 and the lower header 8. Since the downcomer pipe 12 is provided outside the can body, the heat load is zero. Therefore, the water pushed up by the upper header 7 can flow into the downcomer pipe 12, making it easier to flow into the water pipe near the exhaust port 15 and having a high heat load. As a result, water circulation can be promoted even in the water pipe on the side of the exhaust port 15, and the water circulation (water quality) in the can body 2 is made as uniform as possible, thereby suppressing local corrosion of the water pipe and improving the durability of the water pipe. can be increased. Although the example in which the downcomer pipe 12 in this embodiment is provided at a position adjacent to the exhaust port 15 is shown, the downcomer pipe 12 is not limited to this as long as it is provided on the exhaust port 15 side. The exhaust duct 11 may be provided at a position that overlaps with the exhaust duct 11 in the vertical direction (for example, on the Y axis and bypassing the exhaust duct 11).

Furthermore, in the boiler exemplified as Patent Document 1, the water supply port to the lower header is provided on the exhaust port side and on the side where the heat load is high. Further, as described above, in a boiler in which a downcomer pipe is not connected to the exhaust port side where the heat load is high, circulation in the water pipe on the exhaust port side is poor. For this reason, the supplied water is biased toward the exhaust port side, and the high heat load promotes evaporation, making it easy for scale to adhere inside the water pipes on the exhaust port side. As a result, the water pipe on the exhaust port side where scale has locally adhered is likely to be overheated, leading to a decrease in thermal efficiency due to scale adhesion, and there is a possibility that the original heat transfer performance of the boiler cannot be maintained.

Therefore, in the boiler 1 in this embodiment, the water supply port 14 is provided on the side of the lower header 8 opposite to the exhaust port 15. As described above, in the water pipes near the water supply port 14 where the heat load is low, steam is generated slowly and canned water is circulated through the upper header 7. Therefore, it is possible to prevent only the supplied water from being rapidly heated and evaporated, and it is possible to prevent scale from locally adhering to the water pipes near the water supply port 14. As a result, the original heat transfer performance of the boiler can be maintained.

Further, as shown in FIG. 2, the water supply port 14 in this embodiment is provided at a position adjacent to the Y-axis direction and approximately diagonally (for example, 180 degrees opposite side) of the downcomer pipe 12. There is. This makes it diagonal to the blow valve 13a, and prevents fresh water that has just been supplied from being drained (blown) before it is circulated, which further equalizes the water quality and prevents abnormal canned water. This can prevent it from becoming too concentrated. Moreover, the depth size of the boiler 1 can be suppressed, and miniaturization becomes possible. Note that the water supply port 14 is not limited to this as long as it is provided on the side opposite to the exhaust port 15, and for example, the water supply port 14 is located at a position directly opposite to the exhaust port 15 with the center position of the boiler 1 in between (for example, Y It may also be provided on the shaft.

As described above, in this embodiment. A downcomer pipe 12 is communicated with the can body 2 on the exhaust port 15 side. This makes it easier to circulate the can water on the side where it is difficult to circulate due to the high heat load in the can body 2, and the water quality becomes uniform. Therefore, corrosion within the can body 2 is suppressed, and the durability of the boiler is maintained. Further, a water supply port 14 is provided in the lower header 8 on the opposite side to the exhaust port 15. Thereby, local scale adhesion within the can body 2 is suppressed, and the heat transfer performance of the boiler is maintained. As a result, the original performance of the boiler can be maintained.

The present invention is not limited to the embodiments described above, and various modifications and applications are possible. Modifications of the above embodiments applicable to the present invention will be described below.

In the above embodiment, an example in which the steam and water separation is performed only within the upper header 7 has been described. However, it can also be applied to a boiler provided with a steam separator 16 as shown in FIG. In such a boiler, the generated steam flows from the upper header 7 together with the boiled can water into the steam water separator 16 via the communication pipe 17, is separated by the steam water separator 16, and is discharged from the steam supply pipe 6. Steam is extracted. Further, the downpipe 12 is provided to communicate the lower part of the steam water separator 16 and the lower header 8, and the canned water separated by the steam water separator 16 is transferred to the lower header via the downcomer pipe 12. Returned to 8. In this case, a communication pipe that communicates the upper header 7 and the lower header 8 is constituted by a communication pipe 17, a steam separator 16, and a downcomer pipe 12. The communication pipe 17, the steam separator 16, and the downcomer pipe 12 are provided within the can body 2 on the exhaust port 15 side where the heat load is high. That is, the communication pipe 17 is connected to the upper header 7 at a predetermined position on the exhaust port 15 side, and the downcomer pipe 12 is connected to the lower header 8 at a predetermined position on the exhaust port 15 side. This makes it easier to circulate the can water on the side where it is difficult to circulate due to the high heat load in the can body 2, and the water quality becomes uniform. Therefore, corrosion within the can body 2 is suppressed and the durability of the boiler is maintained. Further, since the communication pipe that communicates the upper header 7 and the lower header 8 can also be used as a pipe for connecting the steam separator, it is possible to prevent an increase in the number of parts. Although FIG. 3 shows an example in which the connecting pipe 17 is connected to a position above the upper header 7, the connection pipe 17 is not limited to this as long as it is connected to a position on the exhaust port 15 side of the upper header 7. , it may be connected to a lower position of the upper header 7.

In the above embodiment, as shown in FIG. 1, an example has been described in which water is supplied to the lower header 8 through one water supply port 14. However, the number of water supply ports is not limited to this, and may be provided at a plurality of locations. For example, if two water inlets are provided, the water supply pipe is branched into two routes in the middle, one route is connected to the first water inlet, the other route is connected to the second water inlet, and the two routes are connected. Water may be supplied to the lower header 8 through the water supply port. In this case, the first water supply port and the second water supply port may both be provided at positions opposite to the exhaust port 15 and the downcomer pipe 12. For example, the first water supply port is provided at a position approximately diagonally (for example, 180 degrees opposite) to the downcomer pipe 12, and the second water supply port is provided in the circumferential direction of the can body 2 from the first water supply port. They may be provided at predetermined intervals (a distance corresponding to 20 degrees to 30 degrees). Further, the first water supply port and the second water supply port are spaced apart from each other by a predetermined interval (distance corresponding to 20 degrees to 30 degrees) in the circumferential direction of the can body 2, and the intermediate position of the interval is It may be provided approximately diagonally (for example, 180 degrees opposite side) of the downcomer pipe 12.

As shown in FIG. 1, the inner water pipe 9a in the above embodiment has been described as an example in which the inner vertical fin 9a' is provided so as to close the gap between adjacent water pipes. For example, the water pipes may be arranged close together so that adjacent water pipes are in contact with each other without providing the water pipes. Similarly, for the outer water tubes 9b, the outer vertical fins 9b' may not be provided, and the water tubes may be arranged close together so that adjacent water tubes touch each other.

The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of this invention is indicated by the claims rather than the above description, and it is intended that all changes within the meaning and range equivalent to the claims are included.

1 Boiler 2 Can body 3 Burner 4 Combustion chamber 5 Combustion gas passage 6 Steam supply pipe 7 Upper header 8 Lower header 9a Inner water pipe 9b Outer water pipe 9a' Inner vertical fin 9b' Outer vertical fin 10 Water supply pipe 11 Exhaust duct 12 Downpipe 13 Blow piping 13a Blow valve 14 Water supply port 15 Exhaust port 16 Steam/water separator 17 Communication pipe

Claims (3)

A boiler comprising a plurality of water pipes connecting an upper header and a lower header in a combustion chamber,
an exhaust port that leads out exhaust gas from the combustion chamber;
a communication pipe that communicates the upper header and the lower header outside the combustion chamber,
The communication pipe is provided on the exhaust port side of the boiler. The lower header is provided with a water supply port,
The boiler according to claim 1, wherein the water supply port is provided on a side opposite to the exhaust port. The boiler according to claim 1 or 2, wherein the communication pipe includes a steam separator.

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