JP3640028B2 - Vertical waste heat recovery boiler - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a vertical waste heat recovery boiler having a structure suitable for enlargement in which a tube group and a denitration device are suspended.
[0002]
[Prior art]
A conventional vertical waste heat recovery boiler has a structure in which a pipe group is suspended by a large beam that supports an internal device when a denitration device is not installed, and when a denitration device is installed, the tube group is supported by a tube group support beam for each tube group. This is a structure in which a catalyst support frame mounted with a hanging and denitrating catalyst is fixed and supported on a casing.
[0003]
FIG. 5 is a longitudinal sectional view showing a vertical waste heat recovery boiler according to the prior art.
As shown in this 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 support beam, 24 is a hanging bracket, 25 is a tube group support, 26 is a denitration catalyst, and 27 is a catalyst support frame.
[0004]
The tube groups from the low-pressure economizer 5 to the high-pressure superheater 21 are suspended from the tube group support beam 23 provided at the upper portion of each tube group by the suspension fitting 24 and the tube group support 25. The denitration catalyst 26 is mounted on a catalyst support frame 27 fixed to the casing 2 in consideration of catalyst loading and replacement.
[0005]
In order to prevent a short path of exhaust gas between the denitration catalyst 26 and the casing 2, a seal bar is attached to the denitration catalyst 26, and a seal plate and a slide type seal plate 42 as shown in FIG. 5 are attached between the denitration catalyst 26 and the casing 2. Yes.
[0006]
The high-pressure evaporators 19a and 19b and the high-pressure superheater 21 below the denitration catalyst 26 are connected to a tube group support beam 23 and a suspension fitting 24 provided at an optimal interval for preventing vibration of a tube group different from the catalyst support frame 27. Is suspended.
[0007]
The sliding seal plate 42 is provided to absorb the difference in the expansion direction in the direction perpendicular to the exhaust gas flow between the casing 2 and the catalyst support frame 27 that is thermally expanded by the exhaust gas at 350 ° C. and the internal heat insulating material. A unidirectional expansion is used.
[0008]
In FIG. 5, the exhaust gas having a temperature of about 600 ° C. flows from the exhaust gas inlet duct 1 at the lower part of the boiler and enters the high pressure superheater 21, the high pressure evaporator 19b, the denitration catalyst 26, the high pressure evaporator 19a, the high pressure economizer 14, and the low pressure evaporator. 10. The waste heat is sequentially recovered by the low-pressure economizer 5, the temperature becomes about 150 ° C., and is discharged from the exhaust duct 3 through a chimney (not shown) to the atmosphere.
[0009]
[Problems to be solved by the invention]
Since the above prior art was a low temperature medium capacity type in which the exhaust gas inlet temperature was about 600 ° C., the exhaust gas amount was about 1000 t / h, and the tube group configuration was double pressure non-reheat, the longitudinal dimension of the casing in FIG. The catalyst support frame 27 has a relatively short span and is easy to support.
[0010]
In recent years, gas turbines installed upstream of vertical waste heat recovery boilers have increased flow rates and increased exhaust gas temperatures to improve output and efficiency, exhaust gas inlet temperatures are 650 ° C., flow rates are 2200 t / h, and tube group configurations are also included. When triple pressure reheating and large capacity and complexity are achieved, the longitudinal dimension of the casing is about 15 m, which is three times that of the low temperature medium capacity type, and the span of the catalyst support frame 27 at the bottom of the denitration catalyst 26 becomes longer, and the span that can be supported If this is the case, it cannot be handled by one tower and must be divided into a plurality of towers, resulting in an increase in site area and cost. In addition, the material that can withstand the long span of the catalyst support frame 27 is made of stainless steel in terms of high-temperature strength, and the stainless steel material having a large coefficient of thermal expansion has a long span and the casing 2 and the catalyst support frame 27 have a long span. The countermeasure for the thermal expansion difference is complicated. And every day, it starts and stops repeatedly. S. When there is an S operation, thermal fatigue is a problem for the members and the long spans that increase the strength of the catalyst support frame 27. Therefore, a structure in which an internal device support beam is provided at the lowest temperature portion of the exhaust gas outlet and the entire internal device is suspended by the hanging metal fitting 24 and the tube group support 25 is essential. In this case, since each suspension fitting 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 that is internally insulated. There is almost no need for countermeasures against differential growth.
[0011]
The load of the lower high-pressure superheater 21 and the like needs to be transmitted to the upper high-pressure evaporator 19 through the denitration device 26. However, the strength of the conventional denitration device is weak and there is a problem of replacement of the denitration catalyst 26. .
Further, the interval between the tube group supports 25 is necessary for preventing vibration, the catalyst block has a standard size, and considering the replacement of the denitration catalyst 26, it is necessary to consider the arrangement interval of the hanging metal fittings 24.
[0012]
An object of the present invention is to make it possible to cope with an increase in the size of a vertical waste heat recovery boiler with a built-in denitration device in one tower and to easily carry in and carry out a denitration catalyst.
[0013]
[Means for Solving the Problems]
In order to solve the above problems, a vertical waste heat recovery boiler according to the present invention includes an internal device supporting large beam provided at the top of a casing, and a tube group suspended from the internal device supporting large beam by a plurality of first suspension fittings. And a catalyst suspension frame suspended below the tube group by the first suspension bracket, a catalyst support frame suspended from the catalyst suspension frame by a plurality of second suspension brackets, and mounted on the catalyst support frame A denitration catalyst that is arranged, the arrangement interval of the first suspension fittings is different from the arrangement interval of the second suspension fittings, and the second suspension fittings are arranged at intervals corresponding to the block size of the denitration catalyst. Features.
[0017]
[Action]
By suspending the denitration catalyst frame of the above configuration 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 integrated structure can be obtained without difficulty and the casing needs to be divided Therefore, one tower can be used to increase the size of the vertical waste heat recovery boiler. Furthermore, by setting the arrangement interval of the denitration catalyst frame support means to a value corresponding to the block standard dimension of the denitration catalyst, it becomes easy to carry in and carry out the denitration catalyst .
[0018]
【Example】
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing the overall configuration of an embodiment of the present invention. The configuration of the tube group is basically the same as in FIG. 5, 1 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 first hanging bracket, 25 Is a tube group support, 26 is a denitration catalyst, 27 is a catalyst support frame, 29 is a main body support frame, 30 is an ammonia injection nozzle, and 31 is an internal device support beam. FIG. 2 is an explanatory diagram showing a detailed configuration of the embodiment of the present invention.
[0019]
FIG. 2 is an explanatory diagram showing a detailed configuration of the embodiment of the present invention.
As shown in FIG. 2, 28 is a seal bar, 36 is a height adjusting bracket, 43 is a catalyst suspension frame, and 44 is a monorail. Conventionally, a tube group support beam 23 is provided for each pipe (for example, the low-pressure economizer 5) and is suspended by a suspension bracket 24. In this embodiment, the suspension bracket 24, the height adjustment bracket 36, The tube group support beam 37, the tube group support 25, and the tube group support beam 37 constitute a tube group support means to suspend each tube.
[0020]
The load of the high-pressure superheater 21 and the like below the catalyst support frame 27 and the load of the denitration catalyst 26 and the catalyst support frame 27 are passed through the height adjustment bracket 36 by the suspension bracket 38 that is the second suspension bracket through the gap. To the catalyst suspension frame 43. A catalyst loading / unloading monorail 44 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 is transmitted to the upper tube group support 25 together with the load of the frame itself by the suspension bracket 24 having a suspension interval that matches the tube group support interval suitable for the surrounding conditions of the upper tube group. The load sequentially transmitted in this way is finally transmitted to and supported by the main body support frame 29 via the internal device support large beam 31 provided in the lowest temperature part.
[0021]
The denitration catalyst 26 is mounted on the catalyst support frame 27, and a gap is provided to allow the denitration catalyst 26 to be taken in and out through an appropriate number of suspension fittings 38. Each catalyst including those gaps is sealed by a catalyst support frame 27, a seal bar 28 or direct welding.
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 an optimum interval for the surrounding conditions. It is done.
[0022]
FIG. 3 is an explanatory view showing the configuration of the seal mechanism of the embodiment of the present invention.
As shown in this figure, 2 is a casing, 27 is a catalyst support frame, 32 is a heat insulating material, 33 is a lagging, 34 is a seal plate, and 35 is a bidirectional expansion. As a result of the catalyst support frame 27 moving downward several tens of millimeters during operation of the vertical waste heat recovery boiler, relative displacement with the seal plate 34 attached to the casing 2 occurs in two directions, the vertical direction and the horizontal direction. This is not possible because the seal plate is a slidable seal plate or a unidirectional expansion that slides in the horizontal direction. However, by using the bidirectional expansion 35 that is the sealing mechanism of this embodiment, the difference in elongation due to thermal expansion can be reduced. Absorbs and prevents short path of exhaust gas. The bi-directional expansion 35 may be two metal bellows that absorb the difference in elongation in different directions, but a non-metallic expansion that can absorb in two directions with one expansion is preferable.
[0023]
Next, the carrying-in and carrying-out of the denitration catalyst in the Example of this invention is demonstrated concretely.
FIG. 4 is an explanatory view for explaining loading / unloading of the denitration catalyst according to the embodiment of the present invention.
As shown in this figure, 45 is a catalyst carry-in port and 46 is a catalyst carry-in device.
When the denitration catalyst 26 is carried in / out, a part of the casing 2 is removed, the catalyst carry-in port 45 is opened, and the catalyst loading / unloading monorail 44 is extended to the outside of the casing 2. The catalyst support frame 27 is suspended from the catalyst suspension frame 43 by suspension brackets 38 that are installed at intervals that do not hinder the loading and unloading of the denitration catalyst 26. The denitration catalyst 26 is lifted by the catalyst carry-in device 46 outside the casing 2, moved horizontally between the suspension fittings 38 by the monorail 44 and installed at a predetermined position on the catalyst support frame 27, and then the seal bar 28 shown in FIG. 2 is attached. It is done. After all the denitration catalysts 26 are installed, the extended monorail 44 is removed, and the removed casing 2 is partially restored to complete the loading. Carrying out the replacement of the denitration catalyst 26 can also be performed in the reverse order of the carrying-in.
[0024]
As described above, according to this embodiment, in a vertical waste heat recovery boiler with a built-in denitration device, even if the exhaust gas flow rate is increased to 2000 t / h or more, it is possible to cope with one tower without having to divide into two towers. This makes it possible to exhibit the features of the vertical waste heat recovery boiler used for narrow floors, etc., and is suitable for replacing urban thermal power, which will increase in the future, and can greatly reduce the construction cost.
[0025]
【The invention's effect】
According to the present invention, the denitration catalyst frame carrying the denitration catalyst is suspended and supported at multiple points, so that an integrated structure with a long span is obtained, and there is no need to divide the casing, and the vertical waste heat recovery boiler is increased in size. At that time, one tower can be used.
In addition, by sealing the space between the casing and the denitration catalyst frame with an elastic material that can expand and contract in two directions, the vertical and horizontal movement of the denitration catalyst frame during operation can be reliably absorbed, and a short path of exhaust gas can be prevented. .
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an 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 view for explaining loading / unloading of a denitration catalyst according to an embodiment of the present invention.
FIG. 5 is a longitudinal sectional view showing a vertical waste heat recovery boiler according to the prior art.
6 is a cross-sectional view of the casing top of FIG. 5;
[Explanation of symbols]
DESCRIPTION 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 Tube group support beam 24 Hanging bracket 25 Tube group support 26 Denitration Catalyst 27 Catalyst support frame 28 Seal bar 29 Main body support frame 30 Ammonia injection nozzle 31 Internal device support beam 32 Heat insulating material 33 Lagging 34 Seal plate 35 Bidirectional expansion 36 Height adjustment bracket 37 Tube group support beam 38 Suspension bracket 43 Catalyst suspension Frame 44 Monorail 45 Catalyst loading port 46 Catalyst loading device

Claims (1)

An internal device support girder provided at the top of the casing, a tube group suspended from the internal device support girder by a plurality of first suspension fittings, and suspended below the tube group by the first suspension fitting A catalyst suspension frame, a catalyst support frame suspended from the catalyst suspension frame by a plurality of second suspension metal fittings, and a denitration catalyst mounted on the catalyst support frame. A vertical waste heat recovery boiler in which an arrangement interval is different from an arrangement interval of the second suspension fitting, and the second suspension fitting is arranged at an interval corresponding to a block size of the denitration catalyst .

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