JPH08285206A - Vertical type waste heat recovery boiler - Google Patents

Abstract

PURPOSE: To cope with the increase of the size of a vertical type waste heat recovery boiler with a built-in denitrating device by only one tower. CONSTITUTION: The load of a catalyst support frame 27 on which a denitrating catalyst is placed is transmitted to a catalyst suspension frame 43 through a height adjusting metal fitting 36 by a suspension metal fitting 38. The load transmitted to the catalyst suspension frame 43 is transmitted to an further upper part pipe group support 25 by suspension metal fitting 24 arranged at a suspension distance matched with a pipe group support distance. An orderly transmitted load is finally supported by a main support frame through an internal device support large beam 31 arranged at a lowest temperature part. Further, a bi-directional expansion is located between a casing and the catalyst support frame 27. When the size of a vertical waste heat recovery boiler wherein a long span integral structure is provided is increased in such a way that a denitriding catalyst frame on which a denitrating catalyst is carried is suspended and supported at multipoint, coping with the size increase only by one tower. By using the bi-directional expansion, the difference in elongation in a biaxial direction due to thermal expansion is absorbed and short pass of exhaust gas can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical waste heat recovery boiler having a structure suitable for upsizing by suspending a tube group and a denitration device.

[0002]

2. Description of the Related Art A conventional vertical waste heat recovery boiler has a structure in which a tube group is hung by an internal device supporting girder when a denitration device is not installed. When installing a denitration device, a tube group is supported for each tube group. This is a structure in which a tube group is suspended by a beam, and a catalyst support frame carrying a denitration catalyst is fixed to and supported by a casing.

FIG. 5 is a vertical sectional view showing a vertical type waste heat recovery boiler according to the prior art. As shown in the figure, 1 is an exhaust gas inlet duct, 2 is a casing, 3 is an exhaust gas outlet duct, 5 is a low-pressure economizer, 10 is a low-pressure evaporator, 14 is a high-pressure economizer, and 19a and 19b are high-pressure evaporators. , 21 is a high-pressure superheater, 23 is a tube group supporting beam, 24 is a metal fitting, 25 is a tube group support, 26 is a denitration catalyst, and 27 is a catalyst supporting frame.

The tube groups from the low-pressure coal economizer 5 to the high-pressure superheater 21 are suspended from a tube group support beam 23 provided on the upper side of each tube group by a suspending metal 24 and a tube group support 25. The denitration catalyst 26 is mounted on a catalyst support frame 27 fixed to the casing 2 in consideration of carrying in and replacement of the catalyst.

In order to prevent a short path of exhaust gas between the denitration catalyst 26 and the casing 2, a seal bar is provided on the denitration catalyst 26, a seal plate is provided between the denitration catalyst 26 and the casing 2, and a slide type seal plate 4 as shown in FIG.
2 is installed.

The high-pressure evaporator 19 below the denitration catalyst 26
The a and 19b and the high-pressure superheater 21 are suspended by a tube group support beam 23 and a hanging metal fitting 24, which are provided at optimal intervals for preventing vibration of a tube group different from the catalyst support frame 27.

The slide-type seal plate 42 absorbs the difference in expansion in the direction perpendicular to the exhaust gas flow between the catalyst support frame 27 that thermally expands by the exhaust gas at 350 ° C. and the casing 2 that is covered with the internal heat insulating material and has a small thermal expansion. A unidirectional expansion and contraction is used.

In FIG. 5, the exhaust gas having a temperature of about 600 ° C. flows in from the exhaust gas inlet duct 1 at the bottom of the boiler, and the high pressure superheater 21, the high pressure evaporator 19b, the denitration catalyst 26, and the high pressure evaporator 1 are introduced.
The waste heat is sequentially recovered by 9a, the high-pressure economizer 14, the low-pressure evaporator 10, and the low-pressure economizer 5, and the temperature reaches about 150 ° C. and is discharged from the exhaust gas outlet duct 3 to the atmosphere through a chimney (not shown).

[0009]

According to the above-mentioned prior art, the exhaust gas inlet temperature is about 600 ° C., and the exhaust gas amount is about 1000 t /
h, since the tube group structure is a low-temperature medium-capacity type with double pressure non-reheating, the dimension in the longitudinal direction of the casing in FIG. 6 is relatively short, about 5 m, and the span of the catalyst support frame 27 is short, so that it is easy to support.

In recent years, the flow rate of the gas turbine installed upstream of the vertical waste heat recovery boiler is increased to improve the output and efficiency, and the exhaust gas temperature is also increased at the same time, and the exhaust gas inlet temperature is 65
At 0 ° C, flow rate of 2200 t / h, and tube group configuration with triple pressure reheating and large capacity and complexity, the longitudinal dimension of the casing is about 15 m, which is three times that of the low temperature medium capacity type, and catalyst support at the bottom of the denitration catalyst 26. The span of the frame 27 becomes long, and if it is a span that can be supported, it cannot be handled by one tower and it must be divided into a plurality of towers, resulting in an increase in site area and an increase in cost. Further, the material that can withstand the long span of the catalyst support frame 27 is stainless steel from the viewpoint of high temperature strength, and the fact that the stainless steel material having a large thermal expansion coefficient has a long span means that the casing 2 and the catalyst support frame 27 have a large span. Complicate the measures against the difference in thermal expansion. Then, the D.D.
S. When the S operation is performed, thermal fatigue becomes a problem with the member having the increased strength of the catalyst support frame 27 and the large span. Therefore,
An internal device supporting girder is provided at the lowest temperature portion of the exhaust gas outlet, and a structure in which the entire internal device is suspended by the suspension fitting 24 and the pipe group support 25 is essential. In this case, since the suspension fittings 24 and the tube group support 25 all extend downward, the downward extension of the denitration device 26, the high-pressure superheater 21, etc. reaches several tens of millimeters, but the extension of the casing 2 which is internally heat-insulated. There is almost no such difference, and measures against differential expansion are necessary.

Then, it is necessary to transfer the load of the lower high-pressure superheater 21 and the like to the upper high-pressure evaporator 19 through the denitration device 26, but the conventional denitration device is weak in strength, and the denitration catalyst 26 must be replaced. There's a problem. Further, the interval between the tube group supports 25 is an interval required for vibration prevention, the catalyst block also has a standard size, and in consideration of replacement of the denitration catalyst 26, it is necessary to consider the arrangement interval of the hanging metal fittings 24.

An object of the present invention is to enable a single tower to cope with an increase in the size of a vertical waste heat recovery boiler having a built-in denitration device.

[0013]

The above object is to provide a beam provided on the top of a casing, a tube group support means for suspending a tube group from the beam, and a denitration catalyst frame having a denitration catalyst mounted thereon. This is achieved by having a plurality of denitration catalyst frame supporting means that are more suspended.

A beam is arranged between the tube group supporting means and the denitration catalyst frame supporting means in a direction orthogonal to the loading / unloading direction of the denitration catalyst, and the interval between the denitration catalyst frame supporting means is set to the tube group supporting means. It is desirable to set the interval to a different value.

The above object can be achieved by providing elastic materials which can expand and contract in two different directions between the denitration catalyst frame and the casing.

It is desirable that the elastic material capable of expanding and contracting in two directions having different purposes is one non-metallic expansion.

[0017]

[Operation] By suspending the denitration catalyst frame having the above-mentioned structure from above with the denitration catalyst frame support means, the denitration catalyst frame is supported at equal intervals by the principle of the suspension bridge, so that a long span integral structure can be obtained without difficulty. Since there is no need to divide it, one tower can be used for increasing the size of the vertical waste heat recovery boiler. Further, by setting the arrangement interval of the denitration catalyst frame supporting means to a value corresponding to the block standard size of the denitration catalyst, the denitration catalyst can be easily loaded and unloaded. Further, by providing an elastic material that can expand and contract in two directions between the casing and the denitration catalyst frame, the vertical and horizontal movement of the denitration catalyst frame during operation can be well absorbed to prevent a short path of exhaust gas and The denitration performance can be maintained.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a vertical sectional view showing the overall structure of an embodiment of the present invention. The structure of the tube group is basically the same as in FIG.
Is an exhaust gas inlet duct, 2 is a casing, 3 is an exhaust gas outlet duct, 21 is a high-pressure superheater, 24 is a hanging fitting, 25 is a tube group support, 26 is a denitration catalyst, 27 is a catalyst support frame, 2
9 is a main body support frame, 30 is an ammonia injection nozzle, 31
Is an internal device supporting girder.

FIG. 2 is an explanatory diagram showing the detailed structure of the embodiment of the present invention. As shown in FIG. 2, 28 is a seal bar, 3
6 is a height adjusting metal fitting, 43 is a catalyst suspension frame, and 44 is a monorail. Conventionally, a pipe group support beam 23 is provided for each pipe (for example, the low-pressure coal economizer 5) and is suspended by a suspending metal fitting 24, but in the present embodiment, the internal device supporting girder 31 to the suspending metal fitting 2 are suspended.
4, a combination of the height adjustment fitting 36, the tube group support beam 37, the tube group support 25, and the tube group support beam 37 constitutes a tube group support means to suspend each tube.

High-pressure superheater 2 below the catalyst support frame 27
The load such as 1 and the load of the denitration catalyst 26 and the catalyst support frame 27 are transmitted to the catalyst suspension frame 43 via the height adjustment metal fitting 36 by the suspension metal fitting 38 passing through the gap. A monorail 44 for loading and unloading the catalyst is attached to the catalyst suspension frame 43 and constitutes a part of the suspension frame. The load transmitted to the catalyst suspension frame 43, together with the load of the frame itself, is further transmitted to the upper pipe group support 25 by the hanging metal fittings 24 having a suspension interval matched with the pipe group support interval suitable for the ambient conditions of the upper tube group. The load thus sequentially transmitted is finally transmitted to and supported by the main body support frame 29 via the internal device supporting girders 31 provided in the lowest temperature portion.

The denitration catalyst 26 is mounted on the catalyst support frame 27, and a suitable number of the denitration catalysts 26 are passed through the hanging metal fittings 38 to provide a gap through which the denitration catalyst 26 can be taken in and out. The catalyst supporting frame 27, the seal bar 28, or direct welding is used to seal between the catalysts including the gaps. The load of the tube group installed in the lower part of the denitration device of the high-pressure superheater 21 and the high-pressure evaporator 19b is transmitted to the catalyst support frame 27 by the tube group support 25 and the hanging metal fitting 24 arranged at the optimum intervals for their surrounding conditions. To be

FIG. 3 is an explanatory view showing the construction of the seal mechanism of the embodiment of the present invention. As shown in the figure, 2 is a casing, 27 is a catalyst support frame, 32 is a heat insulating material, 33 is lagging, 34 is a seal plate, and 35 is a bidirectional expansion. As a result of the catalyst support frame 27 moving downward by several tens of mm during operation of the vertical waste heat recovery boiler, the casing 2
The relative displacement with the seal plate 34 attached to the plate occurs in two directions, vertical and horizontal, and cannot be dealt with because the conventional seal plate is a sliding seal plate that slides horizontally or a one-way expansion. By using the bidirectional expansion 35, which is the sealing mechanism of this embodiment, it is possible to absorb the difference in expansion due to thermal expansion and prevent the short path of exhaust gas. The bidirectional expansion 35 may be two metal bellows that absorb the difference in elongation in different directions, but a nonmetallic expansion capable of bidirectional absorption with one expansion is preferable.

Next, the loading and unloading of the denitration catalyst in the embodiment of the present invention will be specifically described. FIG. 4 is an explanatory diagram for explaining the loading / unloading of the denitration catalyst according to the embodiment of the present invention. As shown in the figure, 45 is a catalyst carrying-in port, and 46 is a catalyst carrying-in device. When carrying in / out the denitration catalyst 26, a part of the casing 2 is removed to open a catalyst carrying-in port 45, and a monorail 44 for carrying in / out the catalyst is extended to the outside of the casing 2.
The catalyst support frame 27 has a denitration catalyst 2 from the catalyst suspension frame 43.
6 is suspended by suspending metal fittings 38 installed at intervals so as not to interfere with the carry-in and carry-out of No. 6. The denitration catalyst 26 is hoisted outside the casing 2 by the catalyst carrying-in device 46, horizontally moved between the hanging fittings 38 by the monorail 44, and installed at a predetermined position of the catalyst support frame 27, and then the seal bar 28 shown in FIG. 2 is attached. To be After all the denitration catalysts 26 are installed, the extended monorail 44 is removed, the removed casing 2 is partially restored, and the loading is completed. The removal of the denitration catalyst 26 at the time of replacement can be performed in the reverse order of the loading.

As described above, according to the present embodiment, in the vertical waste heat recovery boiler having a built-in denitration device, even if the exhaust gas flow rate is increased to 2000 t / h or more, it is not necessary to divide it into two towers and one tower is used. Since it can be used, it is possible to make full use of the characteristics of the vertical waste heat recovery boiler used for narrow floors, etc.
It will be suitable for the replacement of urban thermal power, which will increase in the future, and the construction cost can be significantly reduced.

[0025]

According to the present invention, by suspending the denitration catalyst frame carrying the denitration catalyst and supporting it at multiple points, an integral structure with a long span can be obtained, and it becomes unnecessary to divide the casing. One tower can be used for increasing the size of the recovery boiler. In addition, by sealing between the casing and the denitration catalyst frame with an elastic material that can expand and contract in two directions,
The vertical and horizontal movements of the denitration catalyst frame during operation can be reliably absorbed, and the short path of exhaust gas can be prevented.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing the overall configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a detailed configuration of an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a configuration of a seal mechanism according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram illustrating loading / unloading of a denitration catalyst according to an example of the present invention.

FIG. 5 is a vertical cross-sectional view showing a conventional vertical waste heat recovery boiler.

6 is a cross-sectional view of the casing top of FIG.

[Explanation of symbols]

 1 Exhaust Gas Inlet Duct 2 Casing 3 Exhaust Gas Outlet Duct 5 Low Pressure Economizer 10 Low Pressure Evaporator 14 High Pressure Economizer 19a High Pressure Evaporator 19b High Pressure Evaporator 21 High Pressure Superheater 23 Pipe Group Support Beam 24 Suspension Bracket 25 Pipe Group Support 26 DeNOx Catalyst 27 Catalyst support frame 28 Seal bar 29 Main body support frame 30 Ammonia injection nozzle 31 Internal device support girder 32 Insulation material 33 Lagging 34 Seal plate 35 Two-way expansion 36 Height adjustment bracket 37 Tube group support beam 38 Suspension bracket 43 Catalyst suspension Frame 44 Monorail 45 Catalyst import port 46 Catalyst import device

Claims (4)

[Claims] 1. A beam provided on a top portion of a casing, a tube group support means for suspending a tube group from the beam, and a plurality of denitration catalyst frame systems for suspending a denitration catalyst frame carrying a denitration catalyst from the tube group support means. A vertical waste heat recovery boiler having a supporting means. 2. A beam is disposed between the tube group supporting means and the denitration catalyst frame supporting means in a direction orthogonal to the loading / unloading direction of the denitration catalyst, and the denitration catalyst frame supporting means is spaced apart from the tube group. The vertical waste heat recovery boiler according to claim 1, wherein the distance between the support means and the distance is different. 3. The vertical waste heat recovery boiler according to claim 1, wherein elastic materials capable of expanding and contracting in two different directions are provided between the denitration catalyst frame and the casing. 4. The vertical waste heat recovery boiler according to claim 2, wherein the elastic material capable of expanding and contracting in two different directions is one non-metallic expansion.