This application is a National Stage Application, filed under 35 U.S.C. 371, of International Application No. PCT/FI2019/050306, filed Apr. 16, 2019, which international application claims priority to and the benefit of Finland Application No. 20185431, filed May 11, 2018; the contents of both of which as are hereby incorporated by reference in their entirety.
The solution to be presented relates to a support assembly for supporting the furnace of a boiler to a support frame of the boiler. The solution to be presented further relates to a boiler plant comprising a boiler, a support frame for the boiler and a support assembly.
Power boilers, especially steam boilers of CFB (circulating fluidized bed) and BFB (bubbling fluidized bed) design, may be bottom, top or middle supported. In a boiler with a bottom-support system a furnace of the boiler is taken as load that is supported from the bottom by means of a support frame that is a steel structure with horizontal supporting beams and vertical pillars. In a boiler with a top-support system the furnace is taken as load that is supported from the top and suspended from the horizontal supporting beams of the support frame. In a boiler with a mid-support system, the furnace is taken as load that is supported from a mid-point of the furnace by means of the support frame.
The mid-support system is less expensive than the top-support system and less thermal expansion takes place in the top sections of the boiler than in a boiler with a bottom-supported system in which sealing may be problematic due to the thermal expansion.
Attaching the furnace to the support frame of the mid-support system may cause deflection of the walls of the furnace due to loading of brackets and other support assemblies connecting the walls to the support frame, for example to supporting beams of the support frame. As a remedy, reinforcing beams are needed to support the walls and to reduce wall deflection. Therefore, special care should be taken of bending moments at the support assemblies, induced by the weight of the furnace itself.
The support assembly for supporting the furnace of a boiler to a support frame of the boiler according to the solution is presented in claim 1 and in claim 2. The boiler plant comprising a boiler, a support frame for the boiler and the above-mentioned support assembly according to the solution is presented in claim 16.
In the support assembly according to the present solution the furnace comprises four vertical, planar water tube walls which are joined together and which, in a horizontal plane, define a rectangular cross section with four corner sections, two of the water tube walls being joined in each corner section, the four corner sections including a first corner section at which a first water tube wall and a second tube wall that are transverse to each other are joined.
The boiler further comprises at least one vertically extending pipe that is for the transport of water and/or steam and situated outside the furnace, the pipe being close to the first corner section. The support frame further comprises at least two horizontal supporting beams which are separated from the water tube walls and include a first supporting beam and a second supporting beam that are transverse to each other.
In the solution, the support assembly close to the first corner section comprises a first assembly part and a second assembly part. The first assembly part attaches the pipe to the first supporting beam, or to a third supporting beam supported to the first or second supporting beam, wherein the first assembly part defines, at the first or third supporting beam, a first point of support where loads incurred by the weight of the pipe and the furnace attached to the pipe are transmitted to the first or third supporting beam. The second assembly part attaches the same pipe to the second supporting beam, or to a fourth supporting beam supported to the second supporting beam, wherein the second assembly part defines, at the second or fourth supporting beam, a second point of support where loads incurred by the weight of the pipe and the furnace attached to the pipe are transmitted to the second or fourth supporting beam. The support assembly is oblique in relation to the first and second supporting beams.
Alternatively, the support frame further comprises a connecting supporting beam that is separated from the water tube walls and comprises a first end attached to the first supporting beam, or to a third supporting beam supported to the first or second supporting beam, and a second end attached to the second supporting beam, or to a fourth supporting beam supported to the second supporting beam.
In the above-mentioned alternative case of the solution, the first assembly part attaches the pipe to the connecting supporting beam, wherein the first assembly part defines, at the connecting supporting beam, a first point of support where loads incurred by the weight of the pipe and the furnace attached to the pipe are transmitted to the connecting supporting beam. The second assembly part attaches the same pipe to the connecting supporting beam, wherein the second assembly part defines, at the connecting supporting beam, a second point of support where loads incurred by the weight of the pipe and the furnace attached to the pipe are transmitted to the connecting supporting beam. The connecting supporting beam is oblique in relation to the first and second supporting beams.
According to an example, the first and second assembly parts each comprises a suspension device that suspends the pipe from one of the supporting beams, or alternatively from the connecting supporting beam, and provides one of the points of support. According to an example, the suspension device is an adjustable hanger rod.
According to another example, the first and second assembly parts each comprises a supporting leg that is supported by one of the supporting beams and provides one of the points of support.
The boiler plant in which the present solution may be applied comprises the boiler, the support frame for the boiler and the support assembly as explained above.
The support assembly of the presented solution provides the benefit of reducing the bending moments to which a pipe is subjected, and furthermore, avoiding deflections caused by loads incurred by the weight of the pipe and the furnace attached to the pipe.
The above-mentioned benefits are made possible by having not one but two points of support which provide two supporting forces, or two resultant supporting forces, that generate bending moments which cancel each other out either partly or completely at the location of the pipe.
The presented solution will be more fully appreciated by reference to the following detailed description of the illustrative embodiments in accordance with the solution, when taken in conjunction with the accompanying illustrative drawings.
In the figures, the vertical direction is denoted by an arrow Z and two orthogonal, horizontal directions are denoted by arrows X and Y. The horizontal directions are orthogonal in relation to the vertical direction.
The boiler plant in
The support frame 12 comprises several horizontal supporting beams 16, 26, 28, 30, 32, 42 to which the furnace 22 is attached and/or which support the furnace 22 so that the furnace 22 is supported to the ground. Some of the supporting beams may support each other. The supporting beams are supported to the ground by vertical pillars 14 of the support frame 12.
Preferably, the boiler 10 is a steam boiler of CFB (circulating fluidized bed) or BFB (bubbling fluidized bed) design. The boiler 10 may comprise further devices that are relevant for the design in question but are not shown in the figures, for example a boiler and steam circulation system, flue gas channels, superheaters, an economizer, a back pass and a fly ash collection system.
The boiler 10 may additionally comprise a cyclone separator 24 connected to the furnace 22 for separating solid particles from flue gases coming from the furnace 22. The cyclone separator 24 is supported to the support frame 12, for example, by one or more support assemblies, for example supporting legs 70.
The boiler 10 may be, as shown in
The benefit of having the boiler 10 mid-supported is that the cyclone separator 24 may be supported to the support frame 12 in such a way that the cyclone separator 24 extends higher than at least some of the above-mentioned supporting beams, for example the supporting beam 16. The cyclone separator 24 may now be supported from below by, for example, the supporting beam 16.
As shown in
Each water tube wall is made of water tubes attached to each other by means of welded joints, for example. Water to be evaporated into steam is conveyed inside the water tubes. The water tube walls 72, 74, 76, 78 are attached to each other by means of welded joints, for example.
The boiler 10 comprises a pipe 18 that extends vertically and is situated close to the first corner section, at least at the height of the above-mentioned supporting beams. The pipe 18 is situated outside the furnace 22.
The boiler 10 may comprise further pipes similar to the pipe 18 close to one or more of the corners sections, preferable close to each of the four corner sections. The further pipes may apply the same principles as the pipe 18 with regard to supporting the furnace 22.
Preferably, the cross-sectional area of the pipe 18 is larger than that of the water tubes in the water tube walls. Preferably, the pipe 18 has a cross section that is circular in a horizontal plane.
Preferably, the pipe 18 is situated off at least one of horizontal imaginary lines defined by the vertical planes of the water tube walls 76, 78.
The pipe 18 is for the transport of water and/or steam. Preferably, the pipe 18 is a downcomer for the downward transport of water.
According to an example and
Preferably, the pipe 18 is attached to the furnace 22. According to an example and
As shown in the examples of
Adjacent supporting beams that may define the rectangular space are transverse to each other, for example the first and second supporting beams 30, 32. Preferably, the adjacent supporting beams are substantially perpendicular in relation to each other.
Preferably, the supporting beam 26, 28, 30, 32 is substantially parallel with the water tube wall 72, 74, 76, 78 closest to it. For example, the first supporting beam 32 is parallel with the first water tube wall 78 and the second supporting beam 30 is parallel with the second water tube wall 76.
Alternatively, and in the example of
The furnace 22 of the boiler 10 is supported to the support frame 12 by at least one support assembly 34, 36, 38, 40 according to the solution. The support assembly is situated, for example, at the first corner section as shown in
According to an example of the solution and
Thereby, the support assembly 40 with two assembly parts 56, 58 provides the benefit of reducing the bending moments to which the pipe 18 is subjected, and furthermore, avoiding deflections, caused by loads incurred by the weights of the pipe 18 and the furnace 22 attached to the pipe 18. In the examples of
The above-mentioned benefits are made possible by having not one but two points of support which provide two support forces, or two resultant support forces, that generate bending moments that cancel each other out either partly or completely at the location of the pipe 18. Each assembly part 56, 58 defines a point of support 52, 54 via which the above-mentioned loads are transmitted to either the first supporting beam 32 or the second supporting beam 30.
According to an example and
According to an example and
In the example above, each assembly part 56, 58 defines the point of support 52, 54 in such a way that the above-mentioned loads are transmitted first to the connecting supporting beam 84 and then via the connecting supporting beam 84 to the first and second supporting beams 30, 32. According to the example, the two points of support 52, 54 are located at the connecting supporting beam 84.
According to an example and as shown in
According to an example and as shown in
According to a first example and as shown in
According to a second example, the pipe 18 may have a cross section that is circular in a horizontal plane and defines a centre. A first imaginary straight line is defined as extending horizontally via the centre and the first point of support 52. A second imaginary straight line is defined as extending horizontally via the centre and the second point of support 54. According to this example, the angular difference between the first and second imaginary straight lines is less than 35 degrees or preferably less than 25 degrees or most preferably less than 15 degrees. In the examples shown in
According to a third example and as shown in
According to a fourth example and as shown in
One or more of the four examples presented above may be applied simultaneously.
According to an example and
According to an example of the solution and according to
In
In the examples of
In the examples of
In relation to the structure of the supporting beams, the pipe 18, the first and second suspension devices 66, 68, the support assembly 40, the connecting supporting beam 84, the assembly parts 56, 58 and the points of support 52, 54 the examples in
In the examples of
In
According to an example, both the third supporting beam 88 and the fourth supporting beam 86 are in use and each end of the connecting supporting beam 84 is attached to the third or fourth supporting beam 86, 88 as described above in relation to
In the examples above and in
In the examples above and in
In the examples above, the use of the third and/or fourth supporting beams 86, 88 brings the benefit of providing more space between the furnace 22 and the first and/or second supporting beams 30, 32.
In the examples according to
In the examples of
In the examples of
Alternatively, according to an example and as shown in
The principles in the examples presented above in relation to the structure, location and position of the third and fourth supporting beams 86, 88, and those of the third and fourth supporting beams 30, 32, apply to the example of
Functions and elements described in connection with an example above may be used also in the other examples presented above where appropriate. Especially, it should be noted that the examples above may be applied in all four corner sections of the furnace 22 of the boiler 10. The solution presented above in relation to the support assembly may be applied in the four corner sections.
While the invention has been described by way of examples it is to be understood that the solution is not limited to the disclosed examples but is intended to cover various combinations or modifications within the scope of the appended claims.
Number | Date | Country | Kind |
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20185431 | May 2018 | FI | national |
Filing Document | Filing Date | Country | Kind |
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PCT/FI2019/050306 | 4/16/2019 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2019/215383 | 11/14/2019 | WO | A |
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Entry |
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International Searching Authority, International Search Report and Written Opinion for International Application No. PCT/FI2019/050306, dated Jul. 22, 2019, (15 pages), European Patent Office, Rijswijk, Netherlands. |
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Number | Date | Country | |
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20210239313 A1 | Aug 2021 | US |