JP2812872B2 - Furnace tube water tube combination boiler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a furnace tube water tube boiler having a combination of a furnace tube and a water tube.

[0002]

2. Description of the Related Art Conventionally, as a boiler having the highest boiler efficiency among round boilers, a furnace tube boiler as shown in FIG. 9 is widely used. In this type of furnace tube boiler, a cylindrical tube 51 placed horizontally is housed in a drum 50 as a main body, and a combustion burner 52 is provided at one end of the tube 51. The inside of the furnace tube 51 is the combustion chamber 5
3 and the furnace tube 51 having a water portion around the furnace tube 51 constitutes a radiation heat transfer surface.

The other end of the combustion chamber 53 (combustion burner 5
A smoke chamber 54 is formed on the side far from the side 2), and a large number of straight smoke pipes 56 are formed in a part of the rear tube sheet 55 connected to the smoke chamber 54 in the connection structure shown in FIG. 10 or FIG. The smoke tube 56 is disposed in the drum 50 and on the side and above the periphery of the furnace tube 51 in parallel with the furnace tube 51. The smoke tube 56 is immersed in water in the drum 50 to form a contact heat transfer surface, and the outlet side end of the smoke tube 56 communicates with the exhaust duct 57.

[0004] Therefore, the combustion gas in the smoke chamber 54 is indicated by an arrow A1.
The water in the drum 50 is received by the radiant heat transfer and the contact heat transfer in the process of flowing in the direction shown in FIG. Normally, water W inside the drum 50 soaks the furnace tube 51 and the smoke tube 56 except for about 1/3 of the upper portion of the drum 50, thereby forming a steam chamber 58 above the water surface. Then, necessary steam is taken out of the boiler from the steam chamber 58. In addition, each end of the above-mentioned smoke tube 56 is supported by the tube sheet while penetrating the front tube sheet and the rear tube sheet that define the front and rear smoke chambers.

[0005]

However, in the above-mentioned conventional furnace tube boiler, the smoke tube mounting portion serving as a high-temperature gas inlet in the smoke tube is exposed to high-temperature gas and heat from the constituent walls of the smoke chamber 54 is generated. Because of the radiation, the gas is easily overheated locally, and the high-temperature gas and the cold air for purging are repeatedly brought into contact with the start and stop of the boiler, so that a heat cycle of heating and cooling is inevitable. Therefore, there is a problem in that thermal stress is generated in the smoke tube attachment portion, and the smoke tube attachment portion is loosened or cracked, thereby causing early water leakage. Further, in the boiler of the conventional configuration, when the gas temperature of the smoke tube mounting portion is 1100 ° C. or higher, the above-described tendency becomes remarkable, so that the combustion chamber is reduced to perform so-called high load combustion, and the boiler is reduced in size, There was a problem that weight reduction could not be achieved.
Furthermore, when carrying out the high-load combustion miniaturized cylinders, the amount of the NO _x with increasing flame temperature is a problem caused a new harmful effect increases.

The present invention has been made in view of the above circumstances, and does not cause local overheating and thermal stress even if the body size is reduced, and can increase the boiler heat output with a long life. It can further an object to provide a flue water tube combinations boiler which can reduce the NO _x reduction.

[0007]

According to the present invention, there is provided a main body disposed horizontally, a cylindrical furnace tube provided in the main body, and a combustion gas passage passing along the right or left side along the main body. A plurality of vertical water tubes provided, a water tube group arranged parallel to the trunk axis direction of the main body, an upper header connected to the upper end of each vertical water tube, and connected to the lower end of each vertical water tube; A lower header and a steam drum supported by a connecting pipe erected from the main body. The upper header and the steam drum or the connecting pipe are communicated with each other by a brackish water connecting pipe, and the lower header and the main body are connected to each other. This is a furnace tube water tube combination boiler in which a lower part of the inside of the body is communicated with a water communication tube.

In the present invention, the arrangement of the water tubes is substantially in the form of a matrix, and the gap between the vertical water tube rows arranged on the side closest to the main body, and the vertical direction arranged on the side farthest from the main body is formed. It is preferable that the gaps in the water tube row form a membrane wall surface by being connected by vertical fins.

In the present invention, the combustion gas passage is formed of a heat insulating material, and its path passes from the combustion gas outlet of the furnace tube facing the combustion burner to the right or left side along the main body along the combustion chamber. It is preferable to configure so as to return to the burner side. In the present invention, it is preferable that the plurality of vertical water pipes arranged in the low-temperature region of the combustion gas near the combustion burner be constituted by fin tubes for promoting heat transfer.

In the present invention, a plurality of vertical water pipes can be further provided in the combustion gas passage near the combustion tube gas outlet on the side of the furnace tube facing the combustion burner, and each of the upper and lower ends of the water tubes is connected to each other. If the structure is connected to the upper header and the lower header via the connecting pipe, the heat radiation is reduced and the boiler efficiency can be further increased.

[0011]

According to the present invention, the combustion gas generated by the combustion burner causes radiant heat transfer to act on water contained in the compartment between the furnace tube and the main body, and then the combustion gas passage. The water-tube mixture passes through the inside and is guided to the water pipe group, which effectively absorbs the high-temperature combustion gas and becomes a contact heat transfer surface showing a high evaporation rate, and the water-water mixture that absorbed a large amount of heat in the thin water pipe It is guided to the steam drum located above the main body through the upper header and the brackish water connecting pipe.The steam drum actively separates brackish water in the brackish water separation box provided inside, It works to send out less steam.
With this configuration, the main body does not house the smoke tube, so the combustion chamber can be large, and there is no need to expose the combustion gas locally as seen at the junction between the rear tube sheet and the smoke tube. it can.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. The furnace tube water tube combination boiler of the present invention is characterized by being constituted by a combination of a furnace tube and a water tube adopting the technology of a water tube boiler in a round boiler, and FIGS. 1 to 8 show an embodiment of the present invention. It is.

FIG. 1 is a front view showing the configuration of a furnace tube water tube combination boiler according to a first embodiment of the present invention, using a partially broken surface. It should be noted that a combustion gas passage described later is omitted in FIG.

The main configuration of the furnace tube water tube combination boiler 1 is as follows.
A main body 2 arranged laterally, a cylindrical furnace tube 3 provided in the main body 2, and a number of vertical water pipes 4 provided in a combustion gas passage passing along the right or left side of the main body 2.
d, a water pipe group 4 arranged in parallel with the trunk axis direction of the main body 2, an upper header 5 connected to the upper end of each vertical water pipe 4d, and a lower pipe connected to the lower end of each vertical water pipe 4d. A lower header 6 and a steam drum 7 supported by a connecting pipe erected from the main body 2 are provided, and the upper header 5 and the steam drum 7 are communicated with each other by the connection of the brackish water communication pipes 8 and 9. The drawer 6 and the lower part inside the main body 2 are connected to each other by connecting a water communication pipe 10.

Hereinafter, the structure of each part will be described in detail. The main body trunk 2 is arranged with the trunk sideways.
Inside, the furnace tube 3 having a smaller diameter is provided coaxially, and a space enough to be filled with water W is formed between the inner wall surface of the main body 2 and the outer wall surface of the furnace tube 3. A combustion burner 11 is provided at the front end (left end in FIG. 1) of the furnace tube 3.
The combustion gas outlet on the side facing the combustion burner 11 (FIG. 1)
(Right end) communicates with a smoke chamber described later.

The water pipe group 4 is composed of a group of a large number of water pipes 4d extending in the vertical direction.
This will be described with reference to a cross-sectional plan view shown in FIG. In the figure, the water pipes 4d are arranged in a plurality of rows (in the direction of arrow Y) in parallel with the direction of the body axis of the main body 2 (in the direction of arrow X), and substantially form a matrix. The term "substantially matrix-like" means that a material that is not a perfectly aligned matrix is included. That is, the combustion of the burner 11 closer plurality of water tubes 4d that are arranged in the combustion gas low temperature region side, the water pipe 4d _1, 4d _2, 4d _3, the range of the water pipe 4d surrounded by 4d ₄
Is provided with spiral fins 4d 'for promoting heat transfer as shown in FIG. 3 and has a total of five rows in the gas flow direction, while the other water pipes 4d have fins 4d'. 4d 'includes an arrangement having no configuration.

As shown in FIG. 4, a gap between the rows of water pipes 4d arranged closest to the main body 2 in the water pipe group 4 and a water pipe 4d arranged farthest from the main body 2 are formed.
The gaps in the rows are connected by the vertical fins 4b, respectively, and constitute the membrane wall surface. The water pipe 4d mounting portion is configured to be covered with the heat insulating material 17 so as not to receive an endothermic effect, and the water level WL of the canned water is maintained at a level near the coating position (see FIG. 5).

In FIG. 2, PA indicates a combustion gas passage, and a white arrow in the passage indicates a flow of the combustion gas. The combustion gas passage PA is configured by forming a compartment by combining heat insulating materials 12 and 17 such as fire-resistant and heat-insulating castables and rock wool, and the path is on the side of the furnace tube 3 that faces the combustion burner 11. It is configured to pass through the vicinity of one lateral side of the main body 2 from the combustion gas outlet and return to the combustion burner 11 side.

The combustion gas passage PA near the combustion gas outlet
Inside, a plurality of vertical water pipes 4c are arranged.
As shown in the left side view of FIG. 5, each upper end of these water pipes 4c is connected to the upper header 5 via a round upper header (connecting pipe) 13, and each lower end of the water pipe 4c is It is connected to the lower header 6 via a round lower header (communication pipe) 14. The configuration to which the water pipe 4c is added is for reducing heat radiation and further increasing the boiler efficiency.

The upper header 5 has a box shape and is disposed above the water pipe group 4. The upper ends of the water pipe groups 4 are connected by connecting the upper ends of a large number of water pipes 4 d. The lower header 6 also has a box shape and is arranged below the water pipe group 4, and connects the lower ends of a number of water pipes 4 d to collect the lower end side of the water pipe group 4. The upper header 5 communicates with a steam drum 7 described later, and the lower header 6 communicates with a lower compartment between the main body 2 and the furnace tube 2. In the steady operation of the furnace tube water tube combination boiler, water W is not only contained in the compartments between the main body 2 and the furnace tube 3 but also in the lower header 6, the water pipe 4d and the water pipe 4c communicating therewith. Will be filled. The water level of the water W at this time is indicated by WL.

As shown in FIG. 1, the cylindrical steam drum 7 has two connecting pipes 15, which are erected in parallel from the main body 2.
The upper portion of the steam drum 7 is supported by the upper portion of the main body 2 through the connecting pipes 15 and 16. Inside the steam drum 7, a brackish water separation box 7a is provided so that steam with little moisture can be taken out. The inside of the steam drum 7 also communicates with the inside of the upper header 5 through brackish communication pipes 8 and 9 extending from the body side wall. The operation of the first embodiment having such a configuration will be described below.

In FIG. 2, the combustion gas generated by the combustion burner 11 flows along the combustion gas passage P along a white arrow.
A, the combustion gas is radiatively transferred to the water contained in the compartment between the furnace tube 3 and the main body 2 in a path that passes through the inside of the furnace tube 3 and is discharged to the outside. Radiative heat and contact heat transfer to water in the water pipes 4c arranged near the combustion gas outlets, and contact heat transfer to water in the water pipes 4d arranged on the side of the main body 2. These water pipe groups effectively absorb the heat of the combustion gas, exhibit a high evaporation rate, and form a large amount of steam-water mixture in the thin water pipe, and the main body through the upper header 5 and the brackish communication pipes 8 and 9. 2 is guided to a steam drum 7 disposed above the steam drum 7,
The brackish water separation box 7a provided inside actively performs brackish water separation and acts to send out steam with low moisture.
Thereby, efficient heat exchange is performed.

FIGS. 6 to 8 show another embodiment of the present invention. For the sake of simplicity, the same reference numerals will be given to portions having the same functions as in FIG. 1, and description thereof will be omitted. In the present embodiment, as shown in the plan view of FIG. 6, a communication pipe line 20 having substantially the same diameter and functioning as an upper header and a brackish water communication pipe is formed and communicates with each other. Each of the upper ends of the vertical water pipes 21a is distributed and connected to two connecting pipes 20a, 20b extending from the body parts of the connecting pipes 15 and 16 and branching in parallel with the body axis direction of the main body body 2. I have. Further, a water pipe wall 22 arranged in a direction perpendicular to the water pipe group 21 is connected to a connecting pipe 20c located at a rear portion of the main body 2.

As shown in the left side view of FIG. 7 and the right side view of FIG. 8, a water communication pipe 30 having the same structure is formed below the main body 2 in parallel with the communication pipe 20. The water communication pipe 30 is connected to a lower end of the vertical water pipe 21a and a lower end of the water pipe 22 row. 30a and 30b in the figure
Is a water communication pipe disposed opposite to the communication pipes 20a and 20b.

In the water pipe group 21 shown in FIG. 6, the water pipes within the range AR are constituted by fin tubes 21b, and the fin tubes 21b are arranged in a staggered manner. Further, in the water pipe group 21, a gap in a row of water pipes 21 a arranged on a side closest to the main body 2,
The gaps of the water tubes 21a arranged farthest from the main body 2 are connected by vertical fins, respectively, and constitute the membrane wall surface. Similarly, the gap between the water pipes 22 is also connected by vertical fins, and forms a membrane wall as a water pipe wall.

According to the structure of the present embodiment, the structure for connecting the water tube group to the drum and the structure for connecting the water tube group to the lower portion inside the main body can be simplified. This can be performed more easily.
Further, the water pipe of the present invention is not limited to the above embodiment, and may be constituted by a double pipe or a triple pipe.

[0027]

Since the present invention is configured as described above, it has the following effects. By changing the configuration of the contact heat transfer surface of the round boiler from a smoke pipe to a water pipe, there is no longer a part that receives local overheating as seen at the junction between the rear tube sheet and the smoke pipe, and therefore water that is loosened or cracked Leakage is eliminated, thereby extending the life of the boiler.

Therefore, even if the temperature of the combustion gas rises to 1100 ° C. or more, the life of the boiler is not affected, so that the combustion chamber can be designed to be small and high load combustion can be performed, and the boiler can be reduced in size and weight. be able to. Therefore, as compared with a boiler having a furnace tube having the same dimensions, it is possible to increase the heat output of the boiler. Further, the manufacturing cost can be reduced.

Since the smoke tube is removed from the inside of the main body, the diameter of the main body can be reduced. Therefore, for example, even if a person who has completed only a boiler handling skill training without a boiler engineer's license can design a boiler that can be handled (steam boiler with a trunk inner diameter of 750 mm or less and a length of 1300 mm or less). The volume of the combustion chamber can be increased to 2 to 2.2 times that of the conventional one, and the conventional evaporation amount of 1500 kg / h can be increased to 2400 to 2500 kg / h.
Moreover, the combustion chamber load also the boiler thermal power is increased because it is reduced, the low NO _x reduction can be achieved. By separating the contact heat transfer surface and arranging the water tube group in a matrix,
The boiler can be divided and carried in, so that it can be installed even in a narrow installation place.

[Brief description of the drawings]

FIG. 1 is a front view, partially broken away, showing a configuration of an embodiment of the present invention.

FIG. 2 is a plan view showing a configuration of a combustion gas passage and a group of water tubes according to the embodiment.

FIG. 3 is a longitudinal sectional view showing a water tube with a spiral fin according to the embodiment.

FIG. 4 is an enlarged view of a main part showing a vertical fin according to the embodiment.

FIG. 5 is a left side view of FIG. 1;

FIG. 6 is a plan view showing the configuration of another embodiment of the present invention.

FIG. 7 is a left side view of another embodiment.

FIG. 8 is a right side view of another embodiment.

FIG. 9 is a cross-sectional front view showing a configuration of a conventional furnace tube boiler.

FIG. 10 is a cross-sectional view showing a conventional structure for mounting a smoke tube and a tube sheet.

FIG. 11 is a cross-sectional view showing a conventional structure for mounting a smoke tube and a tube sheet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace water tube combination boiler 2 Main body 3 Furnace tube 4 Water tube group 4b Vertical fin 4c Water tube 4d Water tube 4d 'Spiral fin 5 Upper header 6 Lower header 7 Steam drum 8,9 Steam connection pipe 10 Water connection pipe 11 Combustion burner 12 Insulation material PA Combustion gas passage 15, 16 Connection pipe 17 Insulation material

Claims (5)

(57) [Claims] 1. A main body disposed horizontally, a cylindrical furnace tube provided in the main body , and a right side thereof along the main body.
Alternatively, a water pipe group composed of a number of vertical water pipes provided in a combustion gas passage passing on the left side and arranged in parallel with the body axis direction of the main body, and an upper header connected to the upper end of each of the vertical water pipes A lower header connected to a lower end of each of the vertical water pipes, and a steam drum supported by a connection pipe erected from the main body. The upper header and the steam drum or the connection pipe And a lower water pipe connecting the lower header and the lower part of the main body by connecting a water pipe. 2. The arrangement of the water pipe group is substantially in a matrix, and a gap between vertical water pipe rows arranged on the side closest to the main body, and a vertical gap arranged on the farthest side from the main body. 2. A furnace tube water tube combination boiler according to claim 1, wherein the gaps between the directional water tube rows are connected to each other by vertical fins to form a membrane wall surface. 3. The combustion gas passage is made of a heat insulating material,
From the combustion gas outlet on the side of the furnace tube facing the combustion burner, pass along the right or left side along the main body body,
The reactor tube water tube combination boiler according to claim 1, wherein the boiler has a path returning to the combustion burner side. 4. The combination according to claim 2, wherein the plurality of vertical water tubes arranged in a low temperature region of the combustion gas near the combustion burner are constituted by fin tubes for promoting heat transfer. boiler. 5. A plurality of vertical water pipes are further provided in a combustion gas passage near the combustion gas outlet on a side of the furnace tube facing the combustion burner, and upper ends and lower ends thereof are respectively connected via connecting pipes. The reactor tube water tube combination boiler according to any one of claims 1 to 4, wherein the boiler is connected to the upper header and the lower header.