JPH085002A - Natural circulation type water tube boiler facility - Google Patents

Abstract

PURPOSE:To contrive the miniaturization of a facility as well as making of the facility in one unit by a method wherein nitrogen oxide is removed from high-temperature exhaust gas, supplied into a lower side exhaust gas flow passage, through a high-temperature denitrification device, then, the exhaust gas is guided into an upper side exhaust gas flow passage in the form of turning back and is discharged into atmosphere through a natural circulation type water tube boiler and a feed water preheater. CONSTITUTION:The inside of a casing 19 is partitioned into lower and upper side exhaust gas flow passages 21, 22 by a partitioning plate 20 while exhaust gas, introduced from an exhaust gas supplying port 17 connected to an exhaust gas supplying duct 1a, is conducted into the upper side exhaust gas flow passage 22 through the lower side exhaust gas flow passage 21 in the form of turning back. A high-temperature denitrification device 12 is provided in the lower side exhaust gas flow passage 21 of the casing 19 while a natural circulation type water tube boiler 11 is arranged at the downstream side of the high-temperature denitrification device 12 so that boiler tubes 4 penetrate through the partitioning plate 20. On the other hand, a medium-temperature denitrification device 13 is provided at the turning back part 23 between both of flow passages 21, 22 while a feed water preheater 14 is provided in the upper side exhaust gas flow passage 22 at the downstream side of the water tube boiler 11 respectively and a changeover damper 16 is provided in a communicating unit 24, communicating the flow passage 21 with the flow passage 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a natural circulation type water pipe boiler facility.

[0002]

2. Description of the Related Art Generally, natural circulation type water pipe boiler equipment is
As shown in FIG. 2, a brackish water cylinder 2 arranged above the exhaust gas duct 1 in the middle of the exhaust gas duct 1 and the brackish water cylinder 2
A water cylinder 3 arranged so as to be opposed to the exhaust gas duct 1 and located below the exhaust gas duct 1, and an upper end connected to the brackish water cylinder 2 and a lower end penetrating the exhaust gas duct 1 and connected to the water cylinder 3 1 of a number of pipes 4 arranged in parallel in the longitudinal direction and the width direction at predetermined intervals, and a connecting pipe 6 extending from the side of the brackish water cylinder 2 along the exhaust gas duct 1 to the upstream side in the flow direction of the exhaust gas 5. The upper header 7 connected to the tip, and the lower header connected to the tip of the connecting pipe 8 extending from the side near the bottom of the water cylinder 3 along the exhaust gas duct 1 to the upstream side in the flow direction of the exhaust gas 5. 9, the upper end is connected to the upper header 7, and the lower end penetrates through the exhaust gas duct 1 and is connected to the lower header 9, which are arranged in parallel in the longitudinal direction and the width direction of the exhaust gas duct 1 with a predetermined interval. Natural circulation type water pipe with a large number of pipes 10 La 11 disposed, discharge at the upstream side of the tubing 10 of the natural circulation water tube boiler 11 gas duct 1
Along the way, a high temperature denitration device 12 for removing nitrogen oxides (NOx) contained in the exhaust gas 5 is provided, and in the middle of the exhaust gas duct 1 between the pipe 10 and the pipe 4 of the natural circulation type water pipe boiler 11, A medium temperature denitration device 13 for removing nitrogen oxides (NOx) contained in the exhaust gas 5 is provided, and a feed water preheater 14 is provided in the exhaust gas duct 1 downstream of the pipe 4 of the natural circulation type water pipe boiler 11. ,
Further, the exhaust gas duct 1 on the upstream side of the high-temperature denitration device 12 and the exhaust gas duct 1 on the downstream side of the feedwater preheater 14 are connected by a bypass duct 15, and the upstream end of the bypass duct 15 is connected to the upstream side of the bypass duct 15. Position P that closes the end and guides the exhaust gas 5 to the high temperature denitration device 12
1 and a position P2 that closes the exhaust gas duct 1 on the upstream side of the high-temperature denitration device 12 and guides the exhaust gas 5 to the bypass duct 15 by providing a switching damper 16.

When steam is required, if the switching damper 16 is switched to the position P1, the high temperature exhaust gas 5 flowing through the exhaust gas duct 1 is guided to the high temperature denitration device 12, and the high temperature denitration device 12 produces nitrogen oxides. After being removed, the high-temperature exhaust gas 5 that has flowed between the tubes 10 of the natural circulation water tube boiler 11 and has the nitrogen oxides removed, the water cylinder 3 of the natural circulation water tube boiler 11 to the connecting tube 8 and the lower part Heat exchange is performed with the boiler water filling the inside of the pipe 10 via the header 9, the boiler water is heated and vaporized, and the temperature of the exhaust gas 5 is lowered to the required temperature.

The boiler water heated and vaporized in the pipe 10 rises by natural circulation, flows from the upper header 7 through the connecting pipe 6 into the brackish water cylinder 2, and the water in the water cylinder 3 is It flows from the connecting pipe 8 into the pipe 10 through the lower header 9.

The exhaust gas 5 having the required temperature flows through the exhaust gas duct 1 and flows into the intermediate temperature denitration device 13, and after further nitrogen oxides are removed in the intermediate temperature denitration device 13,
The boiler water in the pipe 4 is heated by the exhaust gas 5 of the required temperature from which the nitrogen oxides have been removed, flowing between the pipes 4 of the natural circulation type water pipe boiler 11, and the exhaust gas 5 of which the temperature has further decreased is the feed water preheater 14 And is exchanged with the water in the feed water preheater 14 and then discharged to the atmosphere from the exhaust gas duct 1 located downstream.

The boiler water in the pipe 4 located upstream of the natural circulation type water pipe boiler 11 in the exhaust gas flow direction is heated by the exhaust gas 5 having a relatively higher temperature than in the downstream of the exhaust gas flow direction in the pipe 4. And the boiler water in the pipe 4 located on the downstream side in the exhaust gas flow direction of the natural circulation type water pipe boiler 11 is heated by the exhaust gas 5 having a relatively low temperature as compared with the upstream side in the exhaust gas flow direction, As a result, the boiler water naturally circulates between the steam cylinder 2 and the water cylinder 3, and the generated steam is taken out from the steam cylinder 2.

On the other hand, when steam is not required for the convenience of operation, the switching damper 16 is switched to the position P2,
The exhaust gas duct 1 on the upstream side of the high-temperature denitration device 12 is closed, the exhaust gas 5 is guided to the bypass duct 15, and the bypass duct 15 is bypassed without passing between the high-temperature denitration device 12 and the feedwater preheater 14. To the exhaust gas duct 1 on the downstream side.

[0008]

However, in the natural circulation type water pipe boiler equipment as described above, the high temperature denitration device 12 and the pipe 10 of the natural circulation type water pipe boiler 11 are sequentially arranged from the upstream side to the downstream side of the exhaust gas duct 1. And the medium temperature denitration device 13
And the tube 4 of the natural circulation type water tube boiler 11 and the feed water preheater 1
Since 4 is arranged, the total length becomes long and the size of the equipment cannot be avoided, and the restrictions on the installation place increase, and
With regard to installation, it was necessary to bring each device to the site and assemble it, which had the drawback of increasing the number of man-hours and increasing the cost.

In view of the above situation, the present invention can efficiently remove NOx contained in exhaust gas, can be downsized and unitized as a whole, and can reduce restrictions on installation place, and reduce the number of installation steps. Also, the present invention aims to provide a natural circulation type water pipe boiler facility capable of reducing the cost.

[0010]

The present invention is divided into a lower exhaust gas passage and an upper exhaust gas passage by a partition plate,
Exhaust gas introduced from the exhaust gas supply port connected to the exhaust gas supply duct passes through the lower exhaust gas flow passage, flows through the upper exhaust gas flow passage in a folded manner, and can be discharged from the exhaust gas discharge port connected to the exhaust gas discharge duct. A plurality of pipes having a casing configured as described above, provided with a high temperature denitration device in a lower exhaust gas flow passage of the casing, and having an upper end connected to a brackish water cylinder and a lower end connected to a water cylinder on the downstream side of the high temperature denitration device. A natural circulation type water pipe boiler having an upper part of the pipe located in the upper exhaust gas flow passage and a lower part of the pipe penetrating the partition plate and located in the lower exhaust gas flow passage. , A middle temperature denitration device is provided at a folded portion connecting the lower exhaust gas flow passage and the upper exhaust gas flow passage, and a feed water preheater is provided in the upper exhaust gas flow passage on the downstream side of the natural circulation water tube boiler. A communication part that connects the lower exhaust gas flow passage on the upstream side of the high-temperature denitration device and the upper exhaust gas flow passage on the downstream side of the feed water preheater is formed in the casing, and the communication part is closed from the exhaust gas supply port. A position for guiding the introduced exhaust gas to the high-temperature denitration device and the communication part is opened and the lower exhaust gas flow passage on the upstream side of the high-temperature denitration device is closed to directly introduce the exhaust gas introduced from the exhaust gas supply port to the exhaust gas. A switching damper capable of switching to a position leading to the discharge port is provided in the casing.

[0011]

Therefore, when the switching damper is switched to the position where the communication portion is closed, the high temperature exhaust gas supplied from the exhaust gas supply port of the casing to the lower exhaust gas flow passage is guided to the high temperature denitration device. After the nitrogen oxides are removed in the high-temperature denitration device, the water flows between the tubes of the natural circulation type water tube boiler in the lower exhaust gas flow passage, and the boiler water in the tubes is heated by the high-temperature exhaust gas from which the nitrogen oxides have been removed. Is heated and the exhaust gas whose temperature has dropped to the required temperature flows into the intermediate temperature denitration device in the folded portion, and nitrogen oxides are further removed in the intermediate temperature denitration device.

Thereafter, the exhaust gas at the required temperature from which the nitrogen oxides have been removed is guided to the upper exhaust gas flow passage in a folded manner and flows between the pipes of the natural circulation type water pipe boiler in the upper exhaust gas flow passage, The boiler water in the pipe is heated by the exhaust gas of the required temperature, the exhaust gas with a further lowered temperature is guided to the feed water preheater, and after exchanging heat with the water in the feed water preheater, the exhaust gas discharge duct is connected from the exhaust gas outlet. It is then released into the atmosphere.

In the natural circulation water tube boiler, the boiler water is naturally circulated between the steam cylinder and the water cylinder, and the generated steam is taken out from the steam cylinder.

On the other hand, for the convenience of operation, when steam is not required, the switching damper is switched to a position where the communication portion is opened and the lower exhaust gas flow passage on the upstream side of the high temperature denitration device is closed. The high-temperature exhaust gas that has flowed through the duct from the exhaust gas supply port of the casing to the lower exhaust gas flow passage does not pass between the high-temperature denitration device and the feedwater preheater, but passes directly from the communication section through the upper exhaust gas flow passage to the exhaust gas. It is guided to the exhaust port and flows to the exhaust gas exhaust duct.

That is, in the present invention, the high temperature denitration device, the natural circulation type water tube boiler, the medium temperature denitration device, and the feed water preheater are not arranged linearly but can be efficiently housed in the casing. Therefore, the total length is not long, the size of the equipment is prevented from being increased, restrictions on the installation place are reduced, and each device may be carried in as a unit for installation.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention.
The parts denoted by the same reference numerals as in FIG. 2 represent the same things, and the exhaust gas supply port 1 connected to the exhaust gas supply duct 1a
By providing the partition plate 20 at a predetermined position in the casing 19 in which the exhaust gas discharge port 18 connected to the exhaust gas discharge duct 1b is formed in the upper part,
A lower exhaust gas flow passage 21 and an upper exhaust gas flow passage 22 are formed in the casing 19, and the exhaust gas supply duct 1a is provided.
The exhaust gas 5 introduced from the exhaust gas supply port 17 through the exhaust gas supply port 17 flows through the lower exhaust gas flow passage 21 and the upper exhaust gas flow passage 22 in a folded manner, and can be discharged from the exhaust gas discharge port 18 to the exhaust gas discharge duct 1b. .

The lower exhaust gas passage 2 of the casing 19
1 is provided with a high temperature denitration device 12, and on the downstream side of the high temperature denitration device 12, a natural circulation type water pipe boiler 1 having a large number of pipes 4 whose upper end is connected to a brackish water cylinder 2 and whose lower end is connected to a water cylinder 3.
1 is arranged such that the upper portion of the pipe 4 is located in the upper exhaust gas flow passage 22 and the lower portion of the pipe 4 penetrates the partition plate 20 and is located in the lower exhaust gas flow passage 21. A medium temperature denitration device 13 is provided at a folded portion 23 connecting the lower exhaust gas flow passage 21 and the upper exhaust gas flow passage 22, and a feed water preheater 14 is provided in the upper exhaust gas flow passage 22 on the downstream side of the natural circulation water pipe boiler 11. Set up.

A communication portion 24 is formed in the casing 19 for connecting the lower exhaust gas passage 21 on the upstream side of the high temperature denitration device 12 and the upper exhaust gas passage 22 on the downstream side of the feedwater preheater 14 to each other. A position P1 that closes the communication part 24 and guides the exhaust gas 5 introduced from the exhaust gas supply port 17 to the high-temperature denitration device 12, and a lower exhaust gas passageway that opens the communication part 24 and is upstream of the high-temperature denitration device 12. A position P which closes 21 and guides the exhaust gas 5 introduced from the exhaust gas supply port 17 directly to the exhaust gas discharge port 18.
The switching damper 16 that can be switched to
Provided within 9.

Next, the operation of the above embodiment will be described.

When steam is required, if the switching damper 16 is switched to the position P1, the high temperature exhaust gas 5 supplied to the lower exhaust gas flow passage 21 from the exhaust gas supply port 17 of the casing 19 through the exhaust gas supply duct 1a. Is introduced into the high-temperature denitration device 12 and, after the nitrogen oxides are removed in the high-temperature denitration device 12, flows between the pipes 4 of the natural circulation type water pipe boiler 11 in the lower exhaust gas flow passage 21 to obtain the nitrogen oxides. The boiler water in the pipe 4 is heated by the high-temperature exhaust gas 5 from which the exhaust gas 5 has been removed, and the exhaust gas 5 that has decreased to the required temperature flows into the intermediate-temperature denitration device 13 in the turn-back portion 23, and further nitrogen oxides are generated in the intermediate-temperature denitration device 13. To be removed.

After that, the exhaust gas 5 of the required temperature from which the nitrogen oxides have been removed is folded back to form the upper exhaust gas passage 22.
Is introduced into the upper exhaust gas flow passage 22 and flows between the tubes 4 of the natural circulation water tube boiler 11 in the upper exhaust gas flow passage 22, the boiler water in the tube 4 is heated by the exhaust gas 5 at the required temperature, and the exhaust gas 5 having a further lowered temperature is generated. After being guided to the water supply preheater 14 and exchanging heat with the water in the water supply preheater 14, the exhaust gas discharge port 18
Is discharged to the atmosphere through the exhaust gas discharge duct 1b.

In the natural circulation type water pipe boiler 11, in the lower exhaust gas flow passage 21, the temperature of the pipe 4 located on the upstream side in the exhaust gas flow direction, that is, on the left side in the drawing is located on the downstream side in the exhaust gas flow direction, that is, on the right side in the drawing. In the upper exhaust gas flow passage 22, the temperature of the pipe 4 located on the upstream side in the exhaust gas flow direction, that is, on the right side in the figure is located on the downstream side in the exhaust gas flow direction, that is, on the left side in the figure, while being relatively higher than the temperature of the pipe 4. Although the temperature of the pipe 4 is relatively higher than the temperature of the pipe 4, the temperature of the pipe 4 located on the left side of the figure is higher than the temperature of the pipe 4 located on the right side of the figure, and the temperature of the pipe 4 located on the left side of the figure is total. As the boiler water in 4 rises and the boiler water in the pipe 4 located on the right side in the figure descends, natural circulation of boiler water is performed between the brackish water cylinder 2 and the water cylinder 3. The generated steam is taken out from the steam cylinder 2.

On the other hand, for the convenience of operation, when the steam is not required, the switching damper 16 is switched to the position P2.
The communication part 24 is opened, the lower exhaust gas flow passage 21 on the upstream side of the high temperature denitration device 12 is closed, and the high temperature supplied through the exhaust gas supply duct 1a from the exhaust gas supply port 17 of the casing 19 to the lower exhaust gas flow passage 21. Exhaust gas 5 of
Without passing between the high temperature denitration device 12 and the feed water preheater 14, it is directly guided from the communication part 24 to the exhaust gas discharge port 18 through the upper exhaust gas flow passage 22 and flows to the exhaust gas discharge duct 1b.

That is, in this embodiment, the high temperature denitration device 12, the natural circulation type water tube boiler 11 and the medium temperature denitration device 1 are used.
3 and the feedwater preheater 14 can be efficiently housed in the casing 19 instead of being arranged linearly, the total length is not long and the equipment is not upsized, and the restrictions on the installation location are reduced. At the same time, for installation, each device may be carried in as a unit.

In this way, NOx contained in the exhaust gas 5 can be efficiently removed, the size and unit of the exhaust gas 5 can be reduced as a whole, the restrictions on the installation place can be reduced, and the number of installation steps and the cost can be reduced. it can.

It should be noted that the natural circulation type water pipe boiler equipment of the present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the scope of the present invention.

[0028]

As described above, according to the natural circulation type water pipe boiler equipment of the present invention, NOx contained in the exhaust gas is reduced.
Can be efficiently removed, and the size and unit can be reduced as a whole, the restrictions on the installation place can be reduced, and the excellent effects that the number of installation steps and the cost can be reduced can be achieved.

[Brief description of drawings]

FIG. 1 is a side sectional view of an embodiment of the present invention.

FIG. 2 is a side sectional view of a conventional example.

[Explanation of symbols]

 1a Exhaust gas supply duct 1b Exhaust gas discharge duct 2 Brackish water cylinder 3 Water cylinder 4 Tube 5 Exhaust gas 11 Natural circulation type water tube boiler 12 High temperature denitration device 13 Medium temperature denitration device 14 Water supply preheater 16 Switching damper 17 Exhaust gas supply port 18 Exhaust gas discharge port 19 Casing 20 Partition plate 21 Lower exhaust gas flow passage 22 Upper exhaust gas flow passage 23 Folded portion 24 Communication portion P1 position P2 position

Continuation of front page (72) Inventor Hisashi Honda, 4-41, Showa-cho, Kure-shi, Hiroshima Ishikawajima general-purpose boiler Co., Ltd.

Claims (1)

[Claims] 1. An exhaust gas, which is divided into a lower exhaust gas flow passage and an upper exhaust gas flow passage by a partition plate and is introduced from an exhaust gas supply port connected to an exhaust gas supply duct, passes through the lower exhaust gas flow passage and is folded back. Flows through the upper exhaust gas flow passage at
A casing configured to be discharged from an exhaust gas outlet connected to an exhaust gas discharge duct is provided, a high temperature denitration device is provided in a lower side exhaust gas flow passage of the casing, and a steam turbine is provided with an upper end downstream of the high temperature denitration device. A natural circulation type water pipe boiler having a number of pipes connected to each other and having a lower end connected to a water cylinder, wherein an upper portion of the pipe is located in the upper exhaust gas flow passage and a lower portion of the pipe penetrates the partition plate. Located in the lower exhaust gas flow passage, a middle temperature denitration device is provided at the folded portion connecting the lower exhaust gas flow passage and the upper exhaust gas flow passage, and the natural circulation type water pipe in the upper exhaust gas flow passage A feed water preheater is provided on the downstream side of the boiler, and a communication portion that connects the lower exhaust gas flow passage on the upstream side of the high-temperature denitration device and the upper exhaust gas flow passage on the downstream side of the feed water preheater is provided with the casing. And a position for guiding the exhaust gas introduced from the exhaust gas supply port to the high-temperature denitration device, which is formed in the inside of the exhaust gas, and the lower exhaust gas flow passage on the upstream side of the high-temperature denitration device that opens the communication part. A natural circulation type water pipe boiler facility, characterized in that a switching damper that is capable of switching to a position where the exhaust gas introduced from the exhaust gas supply port is directly guided to the exhaust gas discharge port is provided inside the casing.