KR20230038760A - Heat exchangers and flue gas treatment systems - Google Patents

Abstract

A plurality of heat transfer tubes 45 through which heat can flow, one end of each heat transfer tube 45 being connected, and headers 42, 43 through which heat can flow between the heat transfer tubes 45, the header 42, Provide a heat exchanger (4) having openings (42a, 43a) formed in 43) to expose one end (45a) of the heat transfer pipe (45) to the outside, and an opening and closing part (46) for opening and closing the openings (42a, 43a). do.

Description

Heat exchangers and flue gas treatment systems

The present disclosure relates to a heat exchanger and an exhaust gas treatment system provided with the heat exchanger, and more particularly, to a heat exchanger and flue gas treatment system having a plurality of heat transfer tubes.

BACKGROUND OF THE INVENTION In a boiler for thermal power generation, a gas gas heater (GGH) is known as a heat exchanger for recovering heat from exhaust gas in the boiler or heating the exhaust gas. As a technology related to a gas gas heater, the technology described in Patent Literature 1 is known.

In Patent Document 1 (International Publication No. 2018/139669: WO2018/139669A1), a heat exchange bundle 41 having a plurality of heat transfer tubes 11 and 12 has a columnar shape extending vertically to which the heat transfer tubes 11 and 12 are connected. A configuration in which the headers 42 and 43 are stacked is described. In the structure described in Patent Literature 1, the heat exchange bundle 41 stacked in three stages with the headers 42 and 43 consists of a bottom plate 32, a back plate 33, and a top plate 34, top and bottom. And the rear surface is surrounded, and an exhaust gas flow path is formed therein.

Patent Document 1: International Publication No. 2018/139669 (WO2018/139669A1, [0022]-[0029], FIGS. 3 and 4)

In the heat exchange bundle 41 described in Patent Literature 1, a plurality of heat transfer tubes 11 and 12 are supported by headers 42 and 43, and the headers 42 and 43 correspond to each of the heat transfer tubes 11 and 12. A plug hole 48 is formed on the outer surface of ). The plug hole 48 is normally closed with a plug stopper. Then, in the case where the heat transfer tubes 11 and 12 that are broken and leaking heat occur in the plurality of heat transfer tubes 11 and 12, the plug plug is removed and closed from the plug hole 48. A stopper was inserted and the stopper was covered at the ends (entrances of the fruit) of the failed heat transfer tubes 11 and 12 (for example, see Japanese Unexamined Patent Publication No. 2015-036614 or the like).

Specifically, as a procedure for covering the stopper, the following (1) and (2) are performed.

(1) A waste paper stopper is attached to the tip of a rod-shaped jig, and the jig and a waste paper stopper are inserted through the plug hole 48 at a position corresponding to the failed heat exchanger tubes 11 and 12. Press the waste paper stopper at the entrance.

(2) A base material for welding is inserted through the plug hole 48 next to the plug hole 48 into which the waste plug is inserted, and the waste plug is welded to the entrance and exit of the heat transfer tubes 11 and 12.

In the configuration described in Patent Literature 1, when inserting the waste stopper in procedure (1), the entrance and exit of the heat transfer pipe is visually confirmed through the plug hole through which the jig is inserted, resulting in poor workability and time-consuming operation. there is a problem. In addition, even when welding is performed in step (2), the welding position is visually confirmed by checking the plug hole into which the jig is inserted or the plug hole into which the welding base material is inserted, so that workability is improved. It's bad, and there is a problem that the operation time is long. If a plug hole other than that is used, there is a problem that it requires skill in the work because of the perspective, and it takes time to get used to.

This disclosure makes it a technical subject to improve the workability of the work of abolishing a failed heat exchanger tube.

The subject of the present disclosure can be achieved by adopting the following configuration.

The heat exchanger of the present disclosure,

A plurality of heat transfer pipes through which the heat can flow;

A header to which one end of each of the heat transfer tubes is connected, and a heat medium can flow between the headers and each of the heat transfer tubes;

An opening formed in the header to expose one end of the heat transfer pipe to the outside;

It is characterized in that it is provided with an opening and closing part for opening and closing the opening.

In the heat exchanger described above,

One of the openings capable of exposing ends of all the heat transfer pipes to the outside;

It is characterized in that it includes one opening and closing part disposed to correspond to one of the openings.

In the heat exchanger described above,

It is characterized in that the opening/closing portion detachably supported with respect to the opening portion is provided.

The flue gas treatment system of the present disclosure,

A boiler in which fuel is burned;

It is characterized by comprising the heat exchanger according to any one of the above, disposed in a flow path of a gas generated by burning fuel and exchanging heat with the gas.

According to the heat exchanger of the present disclosure, by opening an opening in the opening/closing portion to expose one end of the heat exchanger tube to the outside, it is possible to improve the workability of closing the failed heat exchanger tube.

According to the present disclosure, by including one opening capable of exposing one end of all the heat transfer tubes to the outside and one opening/closing part disposed corresponding to the one opening, the opening/closing operation becomes easier compared to the case of having a plurality of openings or opening/closing parts. workability can be improved.

According to the present disclosure, compared to the case of a slideable opening and closing portion or a hinge-rotatable opening and closing portion, since the opening and closing portion is detachable, it is possible to prevent the opening and closing portion from interfering with work in an open state.

1 is an explanatory diagram of a flue gas treatment system including a heat exchanger according to Example 1 of the present disclosure.
2 is an explanatory view of the main body of the heat exchanger of Example 1 of the present disclosure.
3 is an exploded view of the heat exchanger of FIG. 2;
4 is an explanatory diagram of a bundle constituting the heat exchanger of the embodiment.
Fig. 5 is an explanatory view of the bundle shown in Fig. 4 in a state where the opening/closing part is removed, Fig. 5(A) is a perspective view, and Fig. 5(B) is a main part sectional view.
6 is an explanatory view of a bolt fixing part in the embodiment, FIG. 6(A) is an explanatory view of a cap nut, and FIG. 6(B) is an explanatory view of a state in which a nut is embedded.
7 is an explanatory diagram of a flue gas treatment system including a heat exchanger according to Example 2 of the present disclosure.
8 is a cross-sectional view of the GGH heat recovery device according to Example 3 of the present disclosure.
Fig. 9 is a graph showing the relationship between the amount of abrasion of heat transfer tubes in the GGH heat recovery machine, the gas flow rate of exhaust gas, and the dust concentration contained in exhaust gas.
10 is a cross-sectional view of the GGH reheater of Example 3 of the present disclosure.
Fig. 11 is a top view of finned heat transfer pipes included in the GGH heat recovery device and the GGH reheater.

Next, while referring to drawings, Examples as specific examples of the embodiments of the present disclosure will be described, but the present disclosure is not limited to the following examples.

In addition, in the description using the following drawings, illustration other than members necessary for explanation is omitted appropriately for ease of understanding.

[Example 1]

1 is an explanatory diagram of a flue gas treatment system including a heat exchanger of the present disclosure.

1, in the exhaust gas treatment system (plant) S to which the heat exchanger of Example 1 is applied, after the exhaust gas from the boiler 1 is introduced into the denitrification device 2 and nitrogen oxides in the exhaust gas are removed, , in the air preheater (A/H) 3, heat is exchanged with air for combustion to the boiler 1. Next, the exhaust gas is introduced into the GGH heat recovery device 4 as an example of a gas-gas heat exchanger, and heat exchange (heat recovery) is performed. Exhaust gas whose gas temperature has decreased after passing through the GGH heat recovery device 4 is introduced into a dust collector (EP: Electrostatic Precipitator) 5 in a state where the air resistance value of dust in the gas has decreased, and the exhaust gas Most of the sold out during the elimination. Thereafter, the exhaust gas is boosted in pressure by the fan 6 and introduced into a flue gas desulfurization (FGD) 7, whereby sulfur oxides and particulate matter in the exhaust gas are partially removed by gas-liquid contact. In the wet flue gas desulfurization device 7, the exhaust gas cooled to the saturated gas temperature is heated by the GGH reheater 8 as an example of a gas-gas heat exchanger using the heat recovered by the GGH heat recovery device 4 (heat exchange, reheating). Exhaust gas passing through the GGH reheater (8) is discharged by the chimney (9).

2 is an explanatory view of the main body of the heat exchanger of Example 1 of the present disclosure.

Figure 3 is an exploded view of the body of the heat exchanger of Figure 2;

4 is an explanatory diagram of a bundle constituting the heat exchanger of the embodiment.

2 and 3, the GGH heat recovery device 4 has a housing 31 as an example of a case. The housing 31 has a plate-shaped rear plate 33 as an example of a rear cover and a plate-shaped top plate 34 as an example of an upper cover. An inter-bundle cover 35 extending in the vertical direction is supported on the front of the housing 31 . The inter-bundle covers 35 extend in the vertical direction (gravity direction), and are arranged in plurality at predetermined intervals in the left-right direction (the direction in which exhaust gas (exhaust smoke) flows). Inside the housing 31, a plurality of heat exchange bundles 41 are accommodated.

2 to 4, each heat exchange bundle 41 has a first header 42 as an example of a first attachment portion and a second header 43 as an example of a second attachment portion. The 1st header 42 and the 2nd header 43 of Example 1 are formed in the shape of a column extending in the vertical direction. Each of the headers 42 and 43 is formed in a shape in which the inside is hollow and the upper and lower ends are closed, and a space capable of floating is formed therein. In addition, a mounting plate 44 protruding in the left-right direction is supported on each of the headers 42 and 43 .

On the rear surface of each header 42, 43, a heat transfer pipe 45 extending backward is supported. The heat transfer pipe 45 is configured to be bent at the rear end or the front end inside the housing 31 and reciprocate in the direction after a plurality of rotations. In addition, a plurality of heat transfer tubes 45 are supported at intervals in the vertical direction by each of the headers 42 and 43 . Both ends of each heat exchanger tube 45 are supported by headers 42 and 43, and the heat transfer tube 45 from the headers 42 and 43 is constituted so that entry and exit of heat is possible.

Each heat exchanger tube 45 is supported by a support member 47 at a central portion in the front-back direction. The support member 47 is formed in a shape in which a plurality of holes through which the heat transfer tubes 45 pass are formed in a plate. Therefore, the heat exchanger pipe 45 is not supported in a cantilever state only by the headers 42 and 43, but is supported by the headers 42 and 43 and the support member 47. In addition, although one support member 47 is shown in the front-back direction and the left-right direction, depending on the length of the heat exchanger pipe 45, it is also possible to provide a plurality of sheets in the front-back direction or to provide a plurality of sheets in the left-right direction.

Fig. 5 is an explanatory view of the bundle shown in Fig. 4 in a state where the opening/closing parts are separated, Fig. 5(A) is a perspective view and Fig. 5(B) is a main part sectional view.

In FIG. 5 , openings 42a and 43a are formed in all of the headers 42 and 43 . The openings 42a and 43a of the embodiment extend in the vertical direction along the headers 42 and 43, and are formed in a size capable of exposing the ends (ports of fruit) 45a of all the heat transfer tubes 45 to the outside, there is.

An opening/closing cover 46 as an example of an opening/closing portion is supported in each of the openings 42a and 43a. The opening/closing cover 46 of the embodiment has a semi-cylindrical cover body 46a and plate-shaped fixing portions 46b protruding outward from both left and right ends of the cover body 46a. The opening/closing cover 46 is formed to a length capable of closing the entire area of the openings 42a and 43a. In addition, the opening/closing cover 46 is fixed to the mounting plate 44 with a fixing portion 46b by means of bolts. Therefore, by removing the bolt 46c, the opening/closing cover 46 is configured to be detachable from the headers 42 and 43. In addition, the fixing method of the opening/closing cover 46 is not limited to fixing with bolts, it is possible to use screws, and it is not impossible to perform partial welding so that it can be easily cut.

It is preferable to provide the opening/closing cover 46 with a handle for the operator to grip at the time of attachment/detachment work, but it is also possible to set it as a structure not provided. When providing a handle, it is preferable to provide a plurality of handles such as a handle for hanging the opening/closing cover 46 from above or a handle for moving the opening/closing cover 46 in the front-back direction.

6 is an explanatory view of a bolt fixing part in the embodiment, FIG. 6(A) is an explanatory view of a cap nut, and FIG. 6(B) is an explanatory view of a state in which a nut is embedded.

In Fig. 6, nuts 44a and 44a' to which bolts 46c are screwed are disposed on mounting plate 44 to fix the opening/closing cover 46 of the embodiment with bolts. As shown in FIG. 6(A), the nut 44a can be fixed to the mounting plate 44, and as shown in FIG. 6(B), the mounting plate 44 It is also possible to make the thickness thicker so that the nut 44a' is embedded in the mounting plate 44.

Further, in the embodiment, a seal SL as an example of a sealing member is disposed along the outer periphery of the openings 42a and 43a. Therefore, in the state where the opening/closing cover 46 is attached to the headers 42 and 43, the boundary portion is closed with the seal SL. Therefore, leakage of the nuts in the headers 42 and 43 to the outside is suppressed.

2-5, between each header 42 and 43, the casing plate 49 as an example of a connecting member is supported so that attachment or detachment is possible. The casing plate 49 has a height corresponding to the height of the headers 42 and 43 in the vertical direction. The casing plate 49 is supported on the mounting plate 44 by bolts (not shown) so that attachment or detachment is possible. When the casing plate 49 is mounted, the headers 42 and 43 are connected. Therefore, when the casing plate 49 is attached, while the headers 42 and 43 and the heat transfer pipe 45 are integrated in a state of high rigidity, it is also possible that the exhaust gas leaks from between the headers 42 and 43. are suppressed

The heat exchange bundle 41 of Example 1 is constituted by the members indicated by the above reference numerals 42 to 49. The heat exchange bundle 41 is configured to be accommodated in the housing 31 as a so-called one unit. And, in the state where the heat exchange bundle 41 is housed in the housing 31, the back plate 33, the top plate 34, the inter-bundle cover 35, the headers 42 and 43, the casing plate 49 or the bottom On the inner side surrounded by the surface, an exhaust gas path through which exhaust gas flows is constituted. And the heat exchanger tube 45 is arrange|positioned in the exhaust gas path, and it is comprised so that heat exchange is possible with the exhaust gas flowing through the exhaust gas path.

In Fig. 2, in the GGH heat recovery device 4 of Example 1, three rows are arranged side by side upstream, midstream, and downstream in the direction in which the exhaust gas flows, and each row upstream, midstream, and downstream has a vertical direction. In this way, three stages of heat exchange bundles 41 are stacked. In the middle heat exchange bundle 41, the lower ends of the headers 42 and 43 are stacked on the upper ends of the headers 42 and 43 of the lower heat exchange bundle 41. Similarly, in the heat exchange bundle 41 of the upper stage, the lower ends of the headers 42 and 43 are stacked on the upper ends of the headers 42 and 43 of the heat exchange bundle 41 of the middle stage.

In addition, since the GGH reheater 8 has the same configuration as the GGH heat recovery device 4, illustration and detailed description are omitted.

(Action of Example 1)

In the flue gas treatment system S of Example 1 having the above configuration, when a heat exchanger tube 45 that is broken due to corrosion or the like and leaking heat occurs in the plurality of heat transfer tubes 45, the ends of the heat transfer tubes 45 that have failed An operation of driving the waste stopper 51 into (45a) is performed. When the waste stopper 51 is inserted, first, the inflow of the heat exchanger bundle 41 is stopped, and the heat transfer pipe 45 is taken out. Next, after the temperature of the headers 42 and 43 is lowered, the opening and closing covers 46 of the headers 42 and 43 are removed. Then, through the opened openings 42a and 43a, the waste stopper 51 is driven into the end portion 45a of the failed heat transfer pipe 45 and welded. Then, the opening/closing cover 46 is mounted, and the heat is introduced into the heat exchange bundle 41.

Therefore, in the heat exchange bundle 41 of the embodiment, when the end portion 45a of the heat exchanger tube 45 is blocked with the waste stopper 51, unlike the plug hole of Patent Document 1, the openings 42a and 43a are wide open. ), it is possible to do the work. Therefore, compared to the conventional configuration in which the naked eye was observed through the plug hole, visual confirmation of the end portion 45a of the heat transfer pipe 45 is easy through the openings 42a and 43a, and the closing plug 51 is welded. It also makes the work easier. Therefore, in the heat exchange bundle 41 of the embodiment, the workability of the work of removing the failed heat transfer pipe 45 can be improved, and the work time can be shortened.

In particular, in the embodiment, with one opening/closing cover 46, the ends 45a of all the heat transfer tubes 45 can be opened (exposed) or closed. Therefore, compared to the case where individual covers are opened and closed for each heat transfer pipe 45, the operation is also easier.

In the embodiment, the gap between the openings 42a and 43a and the opening/closing cover 46 is sealed with a seal SL. In the conventional configuration described in Patent Literature 1, when the heat exchange bundle 41 is used (at the time of heat exchange), plug plugs are attached to a plurality of plug holes, respectively. It is difficult to realistically realize the situation in which all are completely sealed, and leakage of the fruit through the plug stopper has been a problem. On the other hand, in the embodiment, the plug stopper itself is not provided, and is sealed with a seal SL between one opening 42a, 43a and one opening/closing cover 46, and management of the closed state is difficult. Compared to the conventional configuration, it is made easier.

Further, as the heat exchange bundle 41 is used, mud-like drains accumulate on the bottoms of the headers 42 and 43 . In the configuration of the conventional plug hole, drainage of drain was difficult. In contrast, in the embodiment, the openings 42a and 43a are wide open. Accordingly, it is also possible to drain or scrape the drain through the open openings 42a and 43a.

[Example 2]

Next, Example 2 of the present disclosure will be described. Example 2 is a modified example of Example 1, and is the same as Example 1 except for the cases specifically described below. 7 is an explanatory diagram of a flue gas treatment system including a heat exchanger according to Example 2 of the present disclosure.

In the flue gas treatment system S of Example 1, in the wet flue gas desulfurization device 7, the exhaust gas cooled to the saturated gas temperature is recovered by the GGH heat recovery device 4, and the GGH reheater ( 8) was to raise the temperature. In contrast, the flue gas treatment system S of Example 2 recovers heat from the exhaust gas that has passed through the air preheater 3, and uses the recovered heat to produce water supplied to the boiler 1 (boiler feed water). to warm it up.

As shown in FIG. 7 , the flue gas treatment system S of Example 2 includes a heat recovery device (heat exchanger) 10 and a feed water heater (heat exchanger) 11 . The heat recovery device 10 is a device that recovers the heat of the exhaust gas by transferring the heat of the exhaust gas that has passed through the air preheater 3 to a heat medium flowing therein. The fruit heated by the heat recovery device (10) is supplied to the feed water heater (11).

The feed water heater 11 is a device that heats water supplied to the boiler 1 using heat recovered by the heat recovery device 10 . The feed water heater 11 heats the water supplied to the boiler 1 by exchanging heat between the heat medium supplied from the heat recovery device 10 and the water supplied to the boiler 1. The feedwater heater 11 supplies heat used as a heat source for heating water supplied to the boiler 1 to the heat recovery device 10 .

[Example 3]

Example 3 of the present disclosure will be described. Example 3 is a modified example of Example 1, and is the same as Example 1 except for the cases specifically described below. 8 is a cross-sectional view of the GGH heat recovery device 4 of Example 3 of the present disclosure. Arrows shown in Fig. 8 indicate the flow direction of the exhaust gas flowing from the air preheater 3 to the GGH heat recovery device 4.

As shown in Fig. 8, the GGH heat recovery device 4 of this embodiment has three heat exchange bundles 41 arranged from the upstream side toward the downstream side in the flow direction of the exhaust gas. The heat exchange bundle 41A is disposed on the most upstream side in the flow direction of the exhaust gas, and the heat exchange bundle 41C is disposed on the most downstream side in the flow direction of the exhaust gas. A heat exchange bundle 41B is disposed between the heat exchange bundle 41A and the heat exchange bundle 41C.

The heat exchanger tube 45 shown in FIG. 8 has a tube body 45A and a fin 45B attached to the tube body 45A. As shown in Fig. 8, all the heat transfer tubes 45 constituting the heat exchange bundles 41A, 41B, and 41C have a tube body 45A and a fin 45B.

As shown in FIG. 8 , the plurality of heat exchanger tubes 45 are arranged at regular intervals P1 along the flow direction of the exhaust gas passing through the plurality of heat exchanger tubes 45 . Further, the plurality of heat exchanger tubes 45 are arranged at regular intervals P1 along the vertical direction VD orthogonal to the flow direction of the exhaust gas passing through the plurality of heat exchanger tubes 45 .

As shown in FIG. 8 , the plurality of heat transfer tubes 45 are arranged so that the positions in the vertical direction VD of the pair of heat transfer tubes 45 adjacent to the flow direction of the exhaust gas are at the same position. That is, the plurality of heat exchanger tubes 45 are arranged in a square array.

In the square arrangement, the exhaust gas contacts the most upstream portion of the heat transfer pipe 45, but at the downstream portion, contact with the exhaust gas is reduced in a form covered by the most upstream portion with respect to the flow direction of the exhaust gas, To the extent that the contact is reduced, the exhaust gas is easy to flow. In the GGH heat recovery device 4, ash erosion is reduced by arranging all the heat transfer tubes 45 constituting the heat exchange bundles 41A, 41B, and 41C in a square arrangement.

The plurality of heat exchange bundles 41A, 41B, and 41C shown in FIG. 8 are arranged so that the flow velocity between the tubes of the heat transfer tubes 45 is 10 m/s or less. Here, the inter-tube flow velocity of the heat exchanger tubes 45 refers to the flow velocity of the exhaust gas passing between the pair of heat transfer tubes 45 adjacent to the vertical direction VD orthogonal to the flow direction of the exhaust gas. More specifically, the flow velocity between the tubes is measured from the cross-sectional area in the vertical direction VD of the heat exchange bundle 41A at the position of the central axis L1 of the first-stage heat exchanger tube 45 shown in FIG. 8 . It refers to the flow rate of the exhaust gas passing through the cross-sectional area area obtained by subtracting the sum of the cross-sectional areas in the vertical direction (VD).

In the plurality of heat exchange bundles 41A, 41B, and 41C shown in FIG. 8 , the flow velocity between the tubes of the heat transfer tubes 45 is set to 10 m/s or less to suppress wear of the heat transfer tubes 45 . In the GGH heat recovery machine 4, it is generally preferable that the wear rate of the heat transfer tube 45 is about 0.1 mm/year or less.

The inventors of the present invention examined the relationship between the abrasion amount of the heat exchanger pipe 45 of the GGH heat recovery device 4 disposed upstream of the dust collector 5 and the flow rate of the exhaust gas. As a result, the measurement results shown in FIG. 9 were obtained. Fig. 9 is a graph showing the relationship between the abrasion amount of the heat exchanger tube 45 in the GGH heat recovery device 4, the gas flow rate of the exhaust gas, and the dust concentration contained in the exhaust gas. 9, A is the wear limit line set at 0.1 mm/year.

As shown in Fig. 9, the present inventors have a phenomenon in which the wear amount of the heat transfer pipe 45 rapidly increases when the gas flow velocity of the exhaust gas is higher than 10 m/s, regardless of the dust concentration in the exhaust gas. found out Therefore, in the present embodiment, the inter-tube flow velocity of the heat transfer tubes 45 is set to 10 m/s or less in the plurality of heat exchange bundles 41A, 41B, and 41C.

10 is a cross-sectional view of the GGH reheater 8 of Example 3 of the present disclosure. Arrows shown in Fig. 10 indicate the flow direction of the exhaust gas flowing from the wet flue gas desulfurization device 7 to the GGH reheater 8.

As shown in Fig. 10, the GGH reheater 8 of this embodiment has three heat exchange bundles 41 arranged from the upstream side toward the downstream side in the flow direction of the exhaust gas. The heat exchange bundle 41D is disposed on the most upstream side in the flow direction of the exhaust gas, and the heat exchange bundle 41F is disposed on the most downstream side in the flow direction of the exhaust gas. A heat exchange bundle 41E is disposed between the heat exchange bundle 41D and the heat exchange bundle 41F.

The heat exchanger tube 45 constituting the heat exchange bundles 41E and 41F shown in Fig. 10 has a tube body 45A and a fin 45B attached to the tube body 45A. The heat exchanger tube 45 constituting the heat exchange bundle 41D shown in FIG. 10 is a bare tube having a tube body 45A but not having a fin 45B attached thereto. The reason why the heat transfer tube 45 constituting the heat exchange bundle 41D is a bare tube without fins 45B is to suppress the problem of corrosion caused by the mist introduced from the wet flue gas desulfurization device 7 adhering to the heat transfer tube 45. It is for

As shown in FIG. 10 , the plurality of heat exchanger tubes 45 are disposed at regular intervals P2 along the flow direction of the exhaust gas passing through the plurality of heat exchanger tubes 45 . Further, the plurality of heat exchanger tubes 45 are arranged at regular intervals P2 along the vertical direction VD orthogonal to the flow direction of the exhaust gas passing through the plurality of heat exchanger tubes 45 .

As shown in Fig. 10, in the plurality of heat exchanger tubes 45 constituting the heat exchange bundles 41E and 41F, the position of the pair of heat transfer tubes 45 adjacent to the flow direction of the exhaust gas in the vertical direction VD is the same. They are arranged so that they are in position. That is, the plurality of heat exchanger tubes 45 are arranged in a square array. In the GGH reheater 8, ash erosion is reduced by arranging the heat transfer tubes 45 constituting the heat exchange bundles 41E and 41F in a square arrangement.

On the other hand, as shown in FIG. 10 , in the plurality of heat exchanger tubes 45 constituting the heat exchange bundle 41D, the positions in the vertical direction VD of the pair of heat transfer tubes 45 adjacent to the flow direction of the exhaust gas are adjacent to each other. It is arranged so that it may become a position in the middle of a pair of heat exchanger pipes 45 which do. That is, the plurality of heat exchanger tubes 45 are arranged so that the positions of the pair of heat transfer tubes 45 adjacent to the flow direction of the exhaust gas in the vertical direction VD are different in a zigzag arrangement.

In the staggered arrangement, since the portion on the downstream side of the heat transfer pipe 45 is less likely to be covered by the portion on the upstream side, the contact with the exhaust gas increases, but the flow of the exhaust gas becomes resistance to that extent. In the GGH reheater 8, the evaporation efficiency of the mist introduced from the wet flue gas desulfurization device 7 can be increased by arranging the heat transfer tubes 45 constituting the heat exchange bundle 41D in a zigzag arrangement.

The plurality of heat exchange bundles 41D, 41E, and 41F shown in FIG. 10 are arranged so that the flow velocity between the tubes of the heat transfer tubes 45 is 8 m/s or more and 16 m/s or less. As for the flow velocity between pipes, it is more preferable to set it as 12 m/s or more and 16 m/s or less.

Here, the inter-tube flow velocity of the heat exchanger tubes 45 refers to the flow velocity of the exhaust gas passing between the pair of heat transfer tubes 45 adjacent to the vertical direction VD orthogonal to the flow direction of the exhaust gas. More specifically, the flow velocity between the tubes is measured from the cross-sectional area in the vertical direction VD of the heat exchange bundle 41D at the position of the central axis L2 of the first-stage heat exchanger tube 45 shown in FIG. 10 . It refers to the flow rate of the exhaust gas passing through the cross-sectional area area obtained by subtracting the sum of the cross-sectional areas in the vertical direction (VD).

Fig. 11 is a view of the finned heat transfer tubes 45 included in the GGH heat recovery device 4 and the GGH reheater 8 as viewed from above. As shown in FIG. 11, the heat exchanger pipe 45 has a pipe body 45A and a fin 45B attached to the outer circumferential surface of the pipe body 45A. The outer diameter d of the tube body 45A is set to, for example, 30 mm or more and 40 mm or less. The outer diameter DF of the pin 45B is set to, for example, 60 mm or more and 80 mm or less.

As shown in Fig. 11, along the direction in which the tubular body 45A extends, a plurality of pins 45B are attached at a fin pitch (interval) F. In the heat exchanger tube 45 included in the GGH heat recovery device 4 shown in FIG. 8 , the fin pitch F is preferably set to 5.0 mm or more and 11.0 mm or less. In addition, it is preferable to set the pin pitch F to 7.25 mm or more and 10.16 mm or less.

In the finned heat exchanger tube 45 included in the GGH reheater 8 shown in FIG. 9 , the fin pitch F is preferably set to 5.0 mm or more and 11.0 mm or less. In addition, it is preferable to set the pin pitch F to 6.35 mm or more and 8.47 mm or less.

(example of change)

Above, the embodiments and modified examples of the present invention have been described in detail, but the present invention is not limited to the above embodiments and modified examples, and various modifications are made within the scope of the gist of the present invention described in the claims. it is possible Other modified examples (H01) to (H04) of the present invention are exemplified below.

(H01) In the above embodiment, the GGH heat recovery device 4 or the GGH reheater 8 was exemplified as the heat exchanger, but it is not limited thereto. For example, it is applicable also to heat exchangers, such as a superheater.

(H02) In the above embodiment, the opening/closing cover 46 exemplified a detachable configuration by fixing with bolts, but is not limited thereto. For example, it is also possible to set it as a structure which slides in the vertical direction and opens and closes the opening part 42a, 43a. Alternatively, it is also possible to have a configuration in which the opening/closing cover 46 is rotatably supported by the headers 42 and 43 or the mounting plate 44 with hinges to open and close the openings 42a and 43a. It is preferable to provide a locking mechanism or the like for keeping the openings 42a and 43a open so that the cover that slides or the cover that opens around the hinge does not interfere with the operation.

(H03) In the above embodiment, the configuration in which the ends 45a of all the heat transfer tubes 45 are covered with one opening part 42a, 43a and one opening/closing cover 46 has been exemplified, but is not limited thereto. It is also possible to set it as the structure which provides one opening part and an opening/closing cover with respect to two (or more) heat exchanger tubes 45 instead of all heat transfer tubes, for example. Moreover, it is not impossible to set it as the structure which provides an opening part and an opening/closing cover individually for one heat exchanger pipe 45.

(H04) In the above embodiment, a configuration in which the housing 31 has the rear plate 33 and the top plate 34 has been exemplified, but is not limited thereto. It is also possible to use sidewalls or ceilings of the heat recovery chamber in which the heat exchange bundles 41 are accommodated instead of the back plate 33 and the top plate 34 . Moreover, it is also possible to provide the housing 31 with a bottom plate.

1 boiler
4 GGH heat recovery (heat exchanger)
8 GGH reheater (heat exchanger)
10 Heat recovery (heat exchanger)
11 Feedwater heater (heat exchanger)
41, 41A, 41B, 41C, 41D, 41E, 41F Heat Exchange Bundles
42, 43 headers
42a, 43a opening
45 heat pipe
45a One end of the heat pipe
45A pipe body
45B pin
46 opening and closing part
S Exhaust system

Claims (11)

A plurality of heat transfer pipes through which the heat can flow;
A header to which one end of each of the heat transfer tubes is connected, and a heat medium can flow between the headers and each of the heat transfer tubes;
an opening formed in the header to expose one end of the heat transfer tube to the outside;
A heat exchanger comprising an opening and closing portion for opening and closing the opening. The method of claim 1,
One of the openings capable of exposing ends of all the heat transfer pipes to the outside;
A heat exchanger comprising one opening and closing part arranged to correspond to one of the openings. According to claim 1 or claim 2,
A heat exchanger comprising the opening and closing portion detachably supported with respect to the opening portion. The method according to any one of claims 1 to 3,
A pair adjacent to the flow direction so that the flow rate of the gas passing between the pair of heat transfer tubes adjacent to the direction orthogonal to the flow direction of the gas passing through the plurality of heat transfer pipes is 10 m/s or less The heat exchanger characterized in that the heat exchanger is arranged so that the positions of the heat transfer tubes in the orthogonal direction are the same position. The method according to any one of claims 1 to 3,
in the flow direction so that the flow velocity of the gas passing between a pair of the heat exchanger tubes adjacent to the direction orthogonal to the flow direction of the gas passing through the plurality of heat exchanger tubes is 8 m/s or more and 16 m/s or less. A heat exchanger characterized in that a pair of adjacent heat transfer tubes are arranged so that positions in the orthogonal direction are different. The method of claim 5,
The orthogonal direction of the pair of heat exchanger tubes adjacent to the flow direction so that the flow velocity of the gas passing between the pair of heat exchanger tubes adjacent to the orthogonal direction is 12 m/s or more and 16 m/s or less. A heat exchanger characterized in that arranged so that the positions of are different. A boiler in which fuel is burned;
An exhaust gas treatment system comprising the heat exchanger according to any one of claims 1 to 3, disposed in a flow path of gas generated by burning fuel and exchanging heat with the gas. A boiler in which fuel is burned;
The heat exchanger according to any one of claims 1 to 3 for heating the heat medium by gas generated by burning the fuel;
and a feed water heater for heating water supplied to the boiler by the heat medium heated by the heat exchanger. According to claim 7 or claim 8,
A plurality of fins are attached to the heat transfer pipe at intervals along the direction in which the heat exchanger tube extends, and the interval between the plurality of fins is set to 5.0 mm or more and 11.0 mm or less. The method of claim 9,
The heat exchanger is a heat recovery device that recovers heat from the gas discharged from the boiler,
The gas exhaust treatment system according to claim 1, wherein the distance between the plurality of pins is set to 7.25 mm or more and 10.16 mm or less. The method of claim 7,
A wet flue gas desulfurization device for removing sulfur oxides in gas discharged from the boiler,
The heat exchanger is a reheater for heating the gas discharged from the wet flue gas desulfurization device,
A plurality of fins are attached to the heat transfer pipe at intervals along a direction in which the heat exchanger tube extends, and the interval between the plurality of fins is set to 6.35 mm or more and 8.47 mm or less.

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