JP3738917B2 - Reinforcement structure of cyclone in pressurized fluidized bed boiler - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a cyclone reinforcing structure in a pressurized fluidized bed boiler.
[0002]
[Prior art]
A pressurized fluidized bed combustor, which fluidizes and burns coal under pressure, has a thermal efficiency of 40% or more due to a combined cycle combined with a gas turbine, has a high desulfurization rate in the furnace, and generates NOx. Because of its small number of features, it is currently being developed as a new boiler that replaces the conventional fine powder fired boiler.
[0003]
For example, as shown in FIG. 4, the pressurized fluidized bed boiler has a configuration in which a boiler body 1, a cyclone 2, a bed material storage container 3, and the like are stored in a pressure container 4, and coal supplied from the outside. C is combusted in the boiler body 1, and the exhaust gas is sent to the cyclone 2, and the exhaust gas from which the ash is removed by the cyclone 2 is supplied to an external gas turbine (not shown) to perform work (for example, driving a generator). It is supposed to be. Further, in the boiler body 1, a fluidized bed B is formed in which a bed material such as coal ash and sand is fluidized by air A supplied from below, and in this fluidized bed B, steam is generated. The evaporator 5, the superheater 6, and the reheater 7 are inserted. Due to the heat generated by the combustion of coal in the fluidized bed B, water evaporates in the evaporator 5 to become steam, and the steam is further heated in the superheater 6 to become superheated steam, which is provided outside. A steam turbine (not shown) expands and works. Further, the steam whose temperature has been lowered by the steam turbine is heated again by the reheater 7 to become superheated steam, and works again by the external steam turbine.
[0004]
FIG. 5 is an overall configuration diagram of a hexagonal pressurized fluidized bed boiler (hereinafter referred to as a hexagonal boiler) in which the boiler body 1 is in the form of a hexagonal column. In this figure, the hexagonal boiler has a configuration in which a boiler body 1, a cyclone 2, a bed material storage container 3 and the like are stored in a pressure vessel 4 as in FIG. A substantially cylindrical exhaust gas manifold 8 is disposed in the center of the hexagonal boiler, and a plurality of cyclones 2 are disposed around it. The normal cyclone 2 is composed of a primary cyclone 12 and a secondary cyclone 14. Exhaust gas obtained by burning coal supplied from the outside in the boiler body 1 enters the inlet duct 12 a of the primary cyclone 12 from the exhaust gas manifold 8, and enters the primary cyclone 12. The exhaust gas from which the ash has been separated enters the inlet duct 14a of the secondary cyclone 14 from the outlet duct 12b, and finer ash is removed by the secondary cyclone 14, and the external gas turbine (from the outlet duct 14b through the cyclone outlet duct 9) is removed. Exhaust gas is supplied to (not shown).
[0005]
FIG. 6 is a top plan view of a conventional cyclone 2. As described above, the cyclone 2 is usually composed of the primary cyclone 12 and the secondary cyclone 14, but the basic configuration is the same except for the different diameters. Therefore, the top plan view shows the primary cyclone 12 and the secondary cyclone. 14 is common. The upper part of the cyclone 2 has a flat plate shape, and the inlet duct 10 of the cyclone 2 is provided eccentrically from the cyclone 2 like a conch. Therefore, the upper part of the cyclone 2 has a low tolerance for stress. On the other hand, in the pressure vessel 4 and the inlet duct 10 of the cyclone 2, a pressure difference of 0.7 to 2.0 kg / cm ² is generated due to pressure loss in the piping and the like, so that the upper part of the cyclone 2 receives external pressure. ing. Furthermore, since the exhaust gas is at a high temperature of about 870 ° C., creep deformation is likely to occur. Therefore, an iron plate having a height of about 100 mm and a thickness of about 40 mm is arranged radially from the outlet duct 11 as the reinforcing material 15 and is directly along the peripheral surface of the cyclone 2. The cyclone 2 is kept warm by directly covering the reinforcing material 15 with a heat insulating material (not shown). The inlet duct 10 is reinforced by a substantially square reinforcing ring 26.
[0006]
[Problems to be solved by the invention]
However, in the above-described cyclone reinforcement structure, there is a problem that stress concentration occurs in the connecting portion between the reinforcing material and the cyclone outlet duct, and the upper surface of the cyclone is deformed. Furthermore, since a large temperature difference is generated in the height direction of the reinforcing material, there is a problem that the thermal stress on the upper surface of the cyclone is high and cracks are easily generated.
[0007]
The present invention has been made to solve the above-described problems. That is, an object of the present invention is to provide a cyclone reinforcement structure in a pressurized fluidized bed boiler that can prevent the deformation of the upper surface of the cyclone and the occurrence of cracks and can reliably reinforce the cyclone.
[0008]
[Means for Solving the Problems]
According to the present invention, in a cyclone installed in a pressure vessel of a pressurized fluidized bed boiler, exhaust gas from a boiler body is supplied from an inlet duct to remove ash and exhaust gas from which ash has been removed from an outlet duct. Reinforcing material provided parallel to the cyclone upper surface with an outlet duct interposed therebetween, a side plate standing up from the cyclone peripheral surface, a lid for closing the space composed of the upper surface of the cyclone, the reinforcing material, and the side plate, and the side plate and the lid A cyclone reinforcing structure in a pressurized fluidized bed boiler is provided.
[0009]
According to a preferred embodiment of the present invention, three pairs of the reinforcing members are provided so as to cross each other, and the height of the side plate is higher than the height of the reinforcing member, and the side plate constitutes the circumferential surface of the cyclone. Is extended upward. Moreover, you may provide the auxiliary | assistant reinforcement material which connects between the said reinforcement materials.
[0010]
[Action]
According to the configuration of the present invention, since the reinforcing material is provided in parallel with the outlet duct on the upper surface of the cyclone, the reinforcing material and the outlet duct are not connected on the upper surface of the cyclone, and the side plates are connected without interruption. is doing. Therefore, since the surface pressure is received by the cyclone upper surface and the reinforcing material and stress is not concentrated on a certain part, deformation of the cyclone upper surface can be suppressed. Furthermore, the space consisting of the upper surface of the cyclone, the reinforcing material and the side plate is closed with a lid, and the side plate and the lid are covered with a heat insulating material, whereby an air layer is provided on the upper surface of the cyclone, and due to the effect of convection in this air layer, The temperature difference in the height direction of the reinforcing material can be reduced. Therefore, the thermal stress generated on the upper surface of the cyclone can be reduced, and the occurrence of cracks can be prevented.
[0011]
【Example】
Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS. In each figure, the same reference numerals are given to the same parts as in the prior art, and a duplicate description is omitted.
[0012]
FIG. 1 is a top plan view of a cyclone in a pressurized fluidized bed boiler of the present invention, and FIG. 2 is a top side sectional view of the cyclone. The embodiment shown in these drawings constitutes a circumferential surface of the cyclone 2 and three pairs (total of six) of reinforcing members 16 provided in parallel on the upper surface of the cyclone 2 so as to cross each other with the outlet duct 11 interposed therebetween. A side plate 18 with the body portion extending upward, a lid 20 that closes the space formed by the upper surface of the cyclone 2, the reinforcing material 16, and the side plate 18, a heat insulating material 22 that covers the side plate 18 and the lid 20, This is a reinforcing structure of the cyclone 2 including the auxiliary reinforcing material 24 that connects the two. The inlet duct 10 is reinforced by a substantially square reinforcing ring 26 as in the prior art. In FIG. 1, the lid 20 and the heat insulating material 22 are omitted.
[0013]
As the reinforcing material 16, an iron plate having a height of about 100 mm and a thickness of about 30 mm is used as in the conventional case. According to the above-described reinforcing structure, since the reinforcing member 16 connects the side plates 18 without interruption, stress does not concentrate on a part of the reinforcing member 16. In the present embodiment, three pairs of reinforcing members 16 (6 in total) are provided, but a necessary number may be provided depending on the size of the cyclone 2 and usage conditions.
[0014]
If the side plate 18 is made higher by about 5 to 10 mm than the height of the reinforcing material 16, the lid 20 can be formed into a flat plate shape and can be fixed without being dropped just by being placed on the reinforcing material 16. There is no need to do. Further, the lid 20 is divided into several parts so as to be easily placed on the reinforcing material 16. Note that the side plate 18 may be formed of a member similar to the reinforcing material 16 instead of the body portion that constitutes the peripheral surface of the cyclone 2 extending upward. Further, the lid body 20 may have a shape that covers the side plate 18 and the reinforcing material 16 instead of the flat plate shape.
[0015]
Further, at the boundary portion 34 between the side plate 18 and the inlet duct 10, one of the reinforcing members 16 is provided so as to overlap the boundary portion 34, and the reinforcing member 16 is connected to the reinforcing ring 26 of the inlet duct 10. Further, the side plate 18 and its reinforcing material 16 are connected.
[0016]
The sub-reinforcement material 24 may be provided in a necessary number depending on the size of the cyclone, use conditions, and the like, and may be provided between the pair of parallel reinforcement materials 16 or between the non-parallel reinforcement materials 16. It may be provided.
[0017]
In FIG. 2, an air layer 32 is formed by the upper surface of the cyclone 2, the reinforcing material 16, the side plate 18, the lid body 20, and the auxiliary reinforcing material 24, and the side plate 18 and the lid body 20 are covered with the heat insulating material 22. Therefore, the temperature difference in the height direction of the reinforcing material 16, the side plate 18, and the auxiliary reinforcing material 24 can be reduced by the effect of air convection in the air layer 32 and the heat retaining effect of the heat insulating material 22. Therefore, the thermal stress applied to the upper surface of the cyclone 2 can be reduced.
[0018]
Moreover, when the cyclone 2 is a primary cyclone, since the upper surface of the exit duct 11 is on a flat plate, an external pressure is applied and it is necessary to reinforce this as well. FIG. 3 is a top plan view of the outlet duct of the primary cyclone. In this case as well, the structure is basically the same as that of the present embodiment, and the side plate 28 is formed by extending the body portion constituting the peripheral surface of the outlet duct 11 upward, and the center is sandwiched between the side plates 28 in parallel. The reinforcing material 30 is connected. Further, a secondary reinforcing material may be provided.
[0019]
Of course, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.
[0020]
【The invention's effect】
As described above, according to the cyclone reinforcing structure in the pressurized fluidized bed boiler of the present invention, stress does not concentrate on a part of the upper surface of the cyclone. Further, the thermal stress applied to the upper surface of the cyclone can be reduced. Therefore, deformation of the upper surface of the cyclone and generation of cracks can be prevented, and the cyclone can be reliably reinforced and has excellent effects.
[Brief description of the drawings]
FIG. 1 is a top plan view of a cyclone in a pressurized fluidized bed boiler according to the present invention.
FIG. 2 is a cross-sectional side view of the upper part of FIG. 1 AA of the cyclone in the pressurized fluidized bed boiler of the present invention.
FIG. 3 is a top plan view of the outlet duct of the primary cyclone.
FIG. 4 is an overall configuration diagram of a conventional pressurized fluidized bed boiler.
FIG. 5 is an overall configuration diagram of a hexagonal pressurized fluidized bed boiler.
FIG. 6 is a top plan view of a conventional cyclone.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Boiler main body 2 Cyclone 3 Bed material storage container 4 Pressure vessel 5 Evaporator 6 Heater 7 Reheater 8 Exhaust gas manifold 9 Cyclone exit duct 10 Inlet duct 11 Outlet duct 12 Primary cyclone 14 Secondary cyclones 15, 16, 30 Reinforcing material 18, 28 Side plate 20 Lid 22 Heat insulating material 24 Sub reinforcing material 26 Reinforcing ring 32 Air layer 34 Boundary portion

Claims (5)

In a cyclone installed in a pressure vessel of a pressurized fluidized bed boiler, exhaust gas from the boiler body is supplied from an inlet duct to remove ash and exhaust gas from which ash is removed from an outlet duct,
Reinforcing material provided in parallel with the cyclone upper surface across the outlet duct, multiple rows of side plates standing up from the cyclone peripheral surface, a lid for closing the space composed of the upper surface of the cyclone, the reinforcing material, and the side plate, and the side plate And a heat insulating material that covers the lid, and a cyclone reinforcing structure in a pressurized fluidized bed boiler. The cyclone reinforcing structure in a pressurized fluidized bed boiler according to claim 1, wherein three pairs of the reinforcing members are provided so as to cross each other. The cyclone reinforcement structure in a pressurized fluidized bed boiler according to claim 1 or 2, wherein a height of the side plate is higher than a height of the reinforcing material. The cyclone reinforcement structure in a pressurized fluidized bed boiler according to any one of claims 1 to 3, wherein the side plate extends upward from a body portion that forms a circumferential surface of the cyclone. The cyclone reinforcing structure in a pressurized fluidized bed boiler according to any one of claims 1 to 4, wherein a sub-reinforcing material is provided to connect between the reinforcing materials.

Images