JPH0245624Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a natural circulation boiler that facilitates removal and discharge of ash and dust near the water drum of the boiler and improves heat exchange efficiency.

[Conventional technology]

A natural circulation boiler (hereinafter simply referred to as a boiler), as shown in the conventional example shown in FIGS. 3 and 4, has a water drum 31 in the lower part of a boiler 30 and a steam drum 32 in the upper part. A partition wall 3 in which a large number of heat exchanger tubes 33 are arranged in between, and the heat exchanger tubes 33 are arranged in a row in the central part of the boiler 30 in the longitudinal direction.
4 to form a U-shaped flue 35, a burner 36 is provided at the end of one combustion side flue 35a of this U-shaped flue 35, and a burner 36 is provided at the end of the other convection side flue 35b. A waste gas outlet 37 is provided at the exhaust gas outlet 37. Also, soot blowers 38a, 38b, 38 are installed at appropriate intervals on the side walls 43a, 43b, 43c of the boiler 30.
c, and the hearth of the combustion side flue 35a is provided with a chute 39 equipped with a drag chain conveyor 40 for carrying out dust at the bottom, and the convection side flue 35
Two chute 41a, 41b are provided on the hearth of b, so as to sandwich the water drum 31, and screw conveyors 42a, 42b are attached to the bottom of the chute, respectively. Fuel such as pulverized coal injected from the burner 36 in this way is combusted in the combustion side flue 35a, and the combustion gas is transferred to the heat exchanger tube 3 of the convection side flue 35b.
The water in the tank 3 is heated, and the waste gas is discharged to the outside from the discharge port 37. Also, during the operation of the boiler 30, the soot blower 38 is inserted into the boiler 30 at regular intervals.
a, 38b, 38c, and inject fluid such as high pressure air or steam to the side walls 43a, 43b, 43.
Blow off the ash and dust adhering to c and heat exchanger tubes 33,
The ash and dust in the combustion side flue 35a are dropped into a chute 39 and discharged to the outside by a drag chain conveyor 40, and the ash and dust in the convection side flue 35b are dropped into two chute 41a and 41b, respectively. It is discharged to the outside by screw conveyors 42a and 42b.

[Problem that the invention attempts to solve]

By the way, in such a boiler 30, the chute 41a, 41 for ash and dust in the convection side flue 35b is
b are provided on both sides of the water drum 31, so that most of the ash and dust are once deposited on the water drum 31 and then fall into the chute 41a, 41b by the jet flow of the soot blower 38c. It is beginning to be excreted. However, this accumulated ash and dust 44 cannot be completely removed due to the slope of the upper surface of the water drum 31 and the viscosity of the ash and dust, and a certain amount of ash and dust 44 always remain on the water drum 31.
This ash and dust 44 remain on the boiler 30 and act as a heat insulator, inhibiting heat exchange in the boiler 30. Also, since the chute 41a, 41b is provided on both sides with the water drum 31 in between, the chute 41a, 41
The structures of the screw conveyors 42a and 42b are complicated, and the width of the chute 41a and 41b is also narrow, so that ash and dust do not fall smoothly, causing problems such as clogging of the chute 41a and 41b.

The present invention was developed to solve the above problems, and it improves heat exchange efficiency by making it easier to remove ash and dust from the water drum, and improves the chute to prevent ash and dust from falling and discharging. To provide an easy natural circulation boiler.

[Means for solving problems]

The structure of the present invention is a natural circulation boiler in which a water drum is disposed at the lower part of a boiler flue and a steam drum is disposed at the upper part, and a heat transfer tube is arranged between the two drums. is connected to the side wall of the boiler flue, and a water drum is arranged, and nozzles for injecting fluid are arranged along the upper surface of the water drum and perpendicularly to the longitudinal direction of the water drum on the side wall, and the other side of the water drum is connected to the side wall of the boiler flue. It is characterized by having a chute equipped with a screw conveyor at the bottom along the circumferential surface of the conveyor.

[Effect]

This natural circulation boiler removes the ash and dust that has fallen through the boiler flue and accumulated on the top surface of the water drum by injecting fluid such as high-pressure air or steam from nozzles arranged in a row on the side wall of the boiler flue. Ash and dust are removed, and the removed ash and dust are allowed to fall into a chute provided on the other side of the water drum and are discharged to the outside by a screw conveyor.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a natural circulation boiler 1, in which a combustion side flue 2 and a convection side flue 3 are provided parallel to the longitudinal direction of the boiler 1, and a cylindrical flue 3 is provided at the bottom of the convection side flue 3. The water drum 4 has a circumferential surface 4a on one side of the water drum 4.
and the side wall 6c of the convection side flue 3 are joined together, and a steam drum 5 is provided above the convection side flue 3. Both drums 4 and 5 are connected by heat transfer tubes 7 arranged vertically, and heat transfer tubes 7 are arranged in a row between the combustion side flue 2 and the convection side flue 3 in the center of the boiler. A partition wall 7a is formed, and both flues 3 form a U-shaped flue. The end of this combustion side flue 2 has a plurality of burners 8
The hearth is provided with a chute 9 having a drag chain conveyor 10 at its bottom, and a combustion gas outlet 13 is provided at the end of the combustion side flue 3. A chute 11 having a screw conveyor 12 at the bottom thereof is provided along the circumferential surface 4b of the other side of the water drum 4. Further, soot blowers 14a, 14b, 14c are arranged at appropriate intervals at heights approximately in the center of the boiler side walls 6a, 6b, 6c, and a plurality of cleaning nozzles 15 are arranged horizontally in a row on the side wall 6c. There is. This cleaning nozzle 15 is connected to the side wall 6
The nozzle 15 branches from a header 16 disposed horizontally on the outside of the water drum 4 and penetrates the side wall 6c, and the tip of the nozzle 15 is oriented along the upper surface of the water drum 4 in a direction perpendicular to the longitudinal direction of the water drum 4. A jet fluid such as high-pressure air or steam is injected between heat transfer tubes 7 disposed in the convection-side flue 3 . Further, the header 16 is connected to an injection fluid supply pipe 17 having an ON-OFF valve 18 in the middle thereof.

[Effect of the embodiment]

In the natural circulation boiler 1 configured as described above, pulverized coal fuel injected from the burner 8 is combusted in the combustion side flue 2, and the combustion gas heats water in the heat transfer tube 7 in the convection side flue 3. Then, it is discharged to the outside from the discharge port 13. During operation of the boiler 1, the soot blowers 14a, 14b, 14c are inserted into the boiler 1 at regular intervals to inject fluid such as high pressure air or steam to adhere to the side walls 6a, 6b, 6c and the heat exchanger tubes 7. Blow away the ash and dust. Of these, the ash and dust in the combustion side flue 2 fall down the chute 9 and are discharged to the outside by the drag chain conveyor 10. In addition, in the convection side flue 3, some ash and dust fall directly into the chute 11, but most of it is deposited on the water drum 4, and the accumulated ash and dust are injected from the cleaning nozzle 15. It is blown away to the chute 11 side by high-pressure air or steam, falls inside the chute 11, and is discharged to the outside by the screw conveyor 12.

[Effect of idea]

As mentioned above, in this invention, the water drum is placed close to the side wall of the combustion flue, and the chute and screw conveyor for ash and dust are made into one line, so the structure is simpler than that of conventional natural circulation boilers. Also, since the width of the chute can be made wider, it is possible to prevent ash and dust from clogging and allow them to fall smoothly through the chute, reducing manufacturing costs and making it suitable for small boilers. It also becomes easier.
Furthermore, a cleaning nozzle is installed along the top surface of the water drum on the side wall of the heating flue, making it possible to easily remove ash and dust accumulated on the water drum without hindering heat exchange. , the heat exchange efficiency of the boiler is improved.

[Brief explanation of the drawing]

1 and 2 are drawings of a natural circulation boiler according to an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view, and FIG.
The figure is a horizontal sectional view, FIGS. 3 and 4 are drawings of a conventional example, FIG. 3 is a longitudinal sectional view, and FIG. 4 is a horizontal sectional view. 1...Natural circulation boiler, 2...Combustion side flue, 3
...Convection side flue, 4...Water drum, 4a, 4b...
...Surrounding surface of water drum, 5...Steam drum, 6a, 6
b, 6c... side wall, 7... heat exchanger tube, 9, 11... chute, 12... screw conveyor, 15...
Cleaning nozzle.

Claims (1)

[Scope of utility model registration request] In a natural circulation boiler in which a water drum is arranged at the bottom of the boiler flue and a steam drum is arranged at the upper part, and a heat transfer tube is arranged between the two drums, the circumferential surface of one side of the water drum is placed in the boiler flue. A water drum is arranged so as to be joined to a side wall, and a nozzle for ejecting a fluid along the upper surface of the water drum and perpendicular to the longitudinal direction of the water drum is arranged on the side wall, and along the circumferential surface of the other side of the water drum. A natural circulation boiler characterized by having a chute equipped with a screw conveyor.