FI20206113A1

FI20206113A1 - Support element for supporting heat exchanger tubes

Info

Publication number: FI20206113A1
Application number: FI20206113A
Authority: FI
Inventors: Timo Mero
Original assignee: Valmet Technologies Oy
Priority date: 2020-11-06
Filing date: 2020-11-06
Publication date: 2022-05-07
Also published as: WO2022096784A1; FI130834B1; CN220567963U; EP4241035A1; JP2023548519A

Abstract

A support element for supporting at least one horizontal heat exchanger tube (28). The support element (42) is mounted on a vertical support tube (30) and comprises a main body (44) including a hollow interior extending through the main body and surrounding the vertical support tube (30) passing through the hollow interior, at least one supporting arm (46) extends outwardly from and substantially perpendicular to the main body (44). Each supporting arm (46) supports at least one of the heat exchanger tubes (28) in such a way that in a vertical direction a downward movement of the heat exchanger tube is prevented. A system including the support element and vertical support tube (30) for supporting horizontal heat exchanger tubes (28). A flue gas passage (60) of a boiler (10) including the system and a heat exchanger (20).

Description

SUPPORT ELEMENT FOR SUPPORTING HEAT EXCHANGER TUBES Technical field of the solution The presented solution especially relates to a support element for supporting one or more horizontal heat exchanger tubes. The support element is configured to be supported by and mounted on a vertical support tube. Background of the solution A steam generator or a boiler provided for combustion of fuel extracts heat energy from hot flue gases by means of heat exchanger placed in a flue gas passage along which the flue gases flow. The heat exchanger may include horizontal heat exchanger tubes that are adapted to pass heat from the hot flue gases to a fluid, a gas, or steam flowing inside the heat exchanger tubes. A conventional method of supporting the horizontal heat exchanger tubes is to provide a vertical support tube, i.e. a stringer tube, extending past and between the horizontal heat exchanger tubes. The vertical support tube has a plurality of supporting arms fixed by welding to it and the horizontal heat exchanger tubes are supported on the supporting arms preventing the horizontal heat exchanger tubes from bending out of line. Typically, the vertical support tube is cooled by a liquid or gas, e.g. steam.

The multitude of welds on the vertical support tube placed in the hot and N corrosive environment inside the flue gas passage may be problematic and N when a fault appears in the support tube the repair work is difficult in such a - case that the vertical support tube must be replaced. S 30 I When a group of the horizontal heat exchanger tubes must be replaced on N account of a fault in one or several of the horizontal heat exchanger tubes, the = repair work is especially difficult and time-consuming. This is because the S vertical support tube and the supporting arms fixed to it hinder movements of the group of the horizontal heat exchanger tubes and/or collide with it when removing the horizontal heat exchanger tubes from the flue gas passage or installing a new group of horizontal heat exchanger tubes into the flue gas passage. It would be desirable to provide a solution providing improved reliability and/or easier repair work with less time-consuming stages. Brief summary of the solution The support element according to the solution is presented in claim 1.

A system for supporting horizontal heat exchanger tubes, the system including the support element is presented in claim 8. A flue gas passage of a boiler, the flue gas passage including the above- mentioned system in presented in claim 14. Other claims present further details of the examples of the solution. The support element according to the solution is for supporting at least one horizontal heat exchanger tube. The support element is configured to be mounted on a vertical support tube. The support element comprises a main body including a hollow interior extending in a vertical direction through the main body and being configured to surround the vertical support tube passing through the hollow interior, and at least one supporting arm. Each supporting arm extends outwardly from and N substantially perpendicular to the main body. Each supporting arm is N configured to support at least one of the heat exchanger tubes in such a way - that in a vertical direction a downward movement of the heat exchanger tube 3 30 is prevented.

I = n Preferably, each support element includes a plurality of such supporting arms, = e.g. six to thirty-six pieces, for supporting a plurality of horizontal heat

O S exchanger tubes.

O N 35

The system according to the solution comprises a vertical support tube and one or more of the above-mentioned support elements. Each support element is mounted on the vertical support tube.

According to an example, the support element comprises at least one pair of the supporting arms. In each pair, the supporting arms extend in two opposite directions with respect to each other, outwardly from and substantially perpendicular to the main body. Additionally, each pair is configured to support at least one pair of the horizontal heat exchanger tubes that are parallel and adjacent to each other in a horizontal direction. According to an example, for example to enable the mounting of and facilitate installation of the support element and the horizontal heat exchanger tubes, or for use during the installation, the support element is configured to rotate around the vertical support tube. The shape of the hollow interior is configured to allow the support element to rotate around a vertical direction about the vertical support tube. According to an example, for example to enable the mounting of and facilitate installation of the support element, or for use during the installation, the support element is adapted to slide along the vertical support tube. The shape of the hollow interior is configured to allow the support element to slide along the vertical support tube. According to an example, for example to enable installation of the support element, the vertical support tube is cooled by means of a liquid or gas (e.g. N steam) flowing inside the vertical support tube.

N - The flue gas passage of a boiler according to the solution comprises walls 3 30 including a front wall and a back wall enclosing a passage for hot flue gases I and at least one heat exchanger positioned in the passage. The heat N exchanger includes at least two horizontal heat exchanger tubes that are = parallel and adjacent to each other. The heat exchanger is configured to pass S heat from hot flue gases flowing inside the passage to a fluid, a gas, or steam flowing inside the heat exchanger tubes. The flue gas passage further comprises at least one of the above-mentioned systems for supporting the heat exchanger.

The presented solution is particularly advantageous and solves the above- mentioned problems.

For example, the presently disclosed support element removes the need for a multitude of welds on the vertical support tube that is load bearing. The support element can be replaced with a new one without replacing the vertical support tube. The use of vertical support tubes enables a longer heat exchanger and a wider flue gas passage.

The support element can be, for the most part, designed, manufactured, or installed in place separately from the vertical support tube. A plurality of short support elements that may be of uniform structure can be combined to form longer support elements for varying needs.

The presented solution facilitates the replacement of a heat exchanger, or a group of the horizontal heat exchanger tubes in the heat exchanger, for example an element of the heat exchanger. Especially in heat exchangers with a relatively small spacing between adjacent horizontal heat exchanger tubes, when in place in the passage for hot flue gases, removing and/or installing e.g. the element may be problematic, time-consuming, or impossible because the horizontal heat exchanger tubes, or curved tube sections of the horizontal heat exchanger tubes, collide with the adjacent horizontal heat exchanger tubes or the conventional supporting arms fixed to the vertical support tube.

The advantage of the presented solution is that that the support element with N its supporting arms can be rotated about the vertical support tube in such a N way that the supporting arms turn away from the horizontal heat exchanger - tubes and may be placed in parallel to them. Now, for example in a vertically 3 30 extending flue gas passage, the lifting and/or lowering of the heat exchanger I or the group of the horizontal heat exchanger tubes, or the moving of the group N of the horizontal heat exchanger tubes horizontally in a direction parallel to the = horizontal heat exchanger tubes, is possible without colliding with the adjacent S horizontal heat exchanger tubes, or the supporting arms of the support N 35 element.

These and other non-limiting features, characteristics and advantages of the presented solution are more particularly disclosed below. Brief description of the drawings 5 The following is a brief description of the drawings, which are presented for the purposes of illustrating the exemplary embodiments disclosed herein and not for the purposes of limiting the same. Fig. 1 shows in a side view an example of a boiler in which the presented solution can be applied. Fig. 2 shows in a side view an example of a flue gas passage in the flue gas channel of the boiler of Fig. 1, together with a heat exchanger installed in the flue gas passage. Fig. 3 shows a side view of an example of the support element according to presented solution and installed on a vertical support tube. Fig. 4 shows the example of Fig. 3 as seen from above, the support element being in a support position and in a rotated position. Fig. 5 shows a side view of another example of the support element according to presented solution and installed on a vertical support tube.

Fig. 6 shows the example of Fig. 5 as seen from above, the support element N being in a support position and in a rotated position.

N - Fig. 7 shows a side view of the support element of Fig. 3.

O o 30 I Fig. 8 shows the support element of Fig. 7 as seen from above.

O = Fig. 9 shows a side view of the support element of Fig. 5.

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O N 35 Fig. 10 shows the support element of Fig. 9 as seen from above.

Fig. 11 shows a top view of an example of the clamping element as applied in the presented solution. Fig. 12 shows two side views of the clamping element of Fig. 12.

Detailed description of the solution In the description, reference is made to the figures with the following reference numbers and denotations: 10 Boiler 12 Furnace 14 Cyclone 16 Flue gas channel 18 Support frame Heat exchanger 22 Column 24 Supporting beam 26 Hanger 20 28 Horizontal heat exchanger tube 30 Support tube 32 Back wall 34 Front wall 36 Curved tube section 38 Header reservoir 40 Header reservoir N 42 Support element N 44 Main body - 46 Supporting arm S 30 — 48 Bracket x 50 Clamping element n 52 Opening = 54 Notch S 56 Cover part — 58 Skirt part 60 Flue gas passage

A more complete understanding of the features disclosed herein can be obtained by reference to the accompanying drawings. These figures are merely schematic representations and are not intended to indicate relative size and dimensions of the devices or components thereof or to define or limit the scope of the embodiments. The specific terms used in the following description are intended to refer only to the embodiments selected for the drawings and are not intended to define or limit the scope of the disclosure. In the drawings and the description below, like numeric designations refer to devices or components of like function.

In the following, the terms “horizontal” and “vertical” refer to the intended operating positions of the device or component in question when installed in place for implementing the functions of the described solution. The terms “horizontal” and “vertical” are used to indicate direction relative to an absolute reference, i.e. ground level. In the figures, the vertical direction is denoted by an arrow Z and the two orthogonal, horizontal directions are denoted by arrows X and Y. The horizonal directions are orthogonal in relation to the vertical direction. Also, the terms “upper”, “lower”, “on top”, “below”, “upward”, and “downward” relate to the above-mentioned, intended operating positions. The terms “parallel” and "perpendicular? should not be construed to require structures to be absolutely parallel or absolutely perpendicular to each other. The term “opposite” should not be construed to require opposite directions to be absolutely parallel to each other. N Referring to Fig. 1, one embodiment of a steam generator or a boiler 10 in N which the present solution may be applied is shown. The boiler may be a part - of a power plant, a steam boiler plant, or a hot water boiler plant, adapted for 3 30 the production of electric energy, steam, and/or heating energy. = N The boiler 10 includes a furnace 12 for the combustion of fuels and a flue gas = channel 16 for conveying flue gases, i.e. combustion product gases, coming S from the furnace 12. & 35 The boiler 10 may comprise further devices that are relevant for the design in question but are not shown in the figures. The boiler 10 may additionally comprise a cyclone separator 14 connected to the furnace 12 for separating solid particles from the flue gases coming from the furnace 12 and for guiding the flue gases to the flue gas channel 16. The boiler 10 may further comprise a support frame 18 for supporting the furnace 12 and the flue gas channel 16 to the ground.

The support frame 18 may include columns 22, supporting beams 24 and/or hangers 26 for supporting the furnace 12 and/or the flue gas channel 16 to the support frame 18. The boiler 10 may be a boiler of CFB (circulating fluidized bed), BFB (bubbling fluidized bed), or grate boiler design.

The fuel may be a gas, solid fuel or solid waste from various sources, e.g. municipal waste.

The flue gas channel 16 shown in Fig. 1 includes one vertical flue gas passage 60 in which flue gases flow downward.

According to other examples, the flue gas channel 16 may include at least one vertical flue gas passage 60, or two or more consecutive vertical flue gas passages 60 in which flue gases flow downward or upward.

According to another example, the flue gas channel 16 may include a horizontal flue gas passage 60 in which flue gases flow horizontally.

The vertical flue gas passage 60 may be followed by the horizontal flue gas passage 60. The flue gas channel 16 and the flue gas passage(s) 60 may be at least in part a plate structure and/or made of water tube walls within which a gas, e.g. steam, and/or a liquid, e.g. water, flows for extracting heat from hot flue gases.

The flue gas channel 16 may include, positioned in one or more of the flue gas passages 60, one or more heat exchangers 20 for extracting heat from hot flue N gases and for which the present solution may be applied.

The purpose of the N heat exchanger 20 varies, the heat being passed to a fluid, a gas, or steam - flowing inside the heat exchanger 20. The heat exchanger 20 includes heat 3 30 exchanger tubes 28 shown in Fig. 2 within which the fluid, gas, or steam flows. = N Referring to Fig. 2, one embodiment of the heat exchanger 20 which may be = applied in the present solution is shown.

The heat exchangers 20 of the flue S gas channel 16 may include one or more superheaters for superheating steam circulating in the water and steam circulation system of the boiler 10, one or more reheaters for reheating steam, one or more heat exchangers of a boiler bank for heating water-steam mixture, one or more preheaters, e.g.

economizers, for preheating water fed to the water circulation system, and/or one or more air heaters for preheating air before feeding the air into the furnace

12. Referring to Fig. 2, the flue gas passage 60 comprises walls enclosing a passage for hot flue gases, the walls including two side walls, a front wall 34 and a back wall 32 that according to an example are vertical. Referring to Fig. 2, the above-mentioned one or more heat exchangers 20 may be supported on the front wall 34 and/or on the back wall 32. Referring to Figs. 3 to 6, the heat exchanger 20 comprises at least two horizontal heat exchanger tubes 28 that are parallel and adjacent to each other. Preferably, there is a plurality of the horizontal heat exchanger tubes 28 in the heat exchanger. In Fig. 3 and 5 the horizontal heat exchanger tubes 28 are presented in a simplified manner by way of circular shapes. Referring to Fig. 2, according to an example, the heat exchanger 20 comprises one or more elements each composed of at least two horizontal heat exchanger tubes 28 that are parallel, separated by a gap and on top of each other in a vertical direction. The heat exchanger tubes 28 may be connected at their ends by way of a curved tube section 36 in such a way that one or more, for example one to four, separate circuits, each with its own inlet and outlet is formed. The inlets may be connected to a common header reservoir 38 and the outlets may be connected to another header reservoir 40. The header reservoirs 38, 40 may communicate with the water and steam N circulation system of the boiler 10.

N - The element represents a group of the horizontal heat exchanger tubes 28 or 3 30 forms a part of the heat exchanger 20 or constitutes the heat exchanger 20. = N According to the example shown in Fig. 2, the element comprises twentyfour = horizontal heat exchanger tubes 28 on top of each other.

S N 35 Referring to Figs. 3 and 5, according to an example, the heat exchanger 20 comprises two or more of the elements that are parallel and adjacent to each other in a horizontal direction in such a way that at least two pairs of the horizontal heat exchanger tubes 28 on top of each other in a vertical direction is formed. In the above-mentioned example, two of the adjacent elements form twenty-four pairs of the horizontal heat exchanger tubes 28 on top of each other. Similar type header reservoirs 38, 40 may be combined to form a common header reservoir. Four or more of the above-mentioned elements form at least two pairs of the horizontal heat exchanger tubes 28 adjacent to each other in the horizontal direction.

Referring to Fig. 2, the heat exchanger 20 is supported on at least one vertical support tube 30, also known as a stringer tube or a hanger tube. One embodiment of the vertical support tube 30 which may be applied in the present solution is shown in Figs. 2 to 6.

Referring to Figs. 3 to 5, the at least one vertical support tube 30 may pass through the exchanger 20 in such a way that it extends in a vertical direction and it is located between the adjacent horizontal heat exchanger tubes 28 of the pairs on top of each other.

The vertical support tube 30 provides additional supporting forces for holding up loads incurred by the heat exchanger tubes 28. According to an example, between the front and back walls 32, 34 the heat exchanger 20 is supported on the at least one vertical support tube 30. For example, a middle section of the heat exchanger 20 is supported on the at least one vertical support tube

30.

S N According to an example, for improved service life, the vertical support tube 30 - is cooled by means of a liguid or gas flowing inside the vertical support tube 3 30 30. The vertical support tube 30 may communicate with the water and steam I circulation system of the boiler 10. The vertical support tube 30 may be top N supported, for example supported, by a suspension arrangement, to the flue = gas channel 16 or to the support frame 18, and/or bottom-supported, for S example supported by a header reservoir connected to the vertical support & 35 tube 30.

According to an example the vertical support tube 30 is circular and/or formed by a circular pipe. The vertical support tube 30 is made for example from weldable steel. A support element 42 according to the solution is shown in Figs. 3 and 5. Two embodiments of the support element 42 which may be applied in the present solution are shown in Figs. 3 to 10. The support element 42 is configured to support at least one of the horizontal heat exchanger tubes 28. The support element 42 is configured to be mounted on the vertical support tube 30. Alternatively, or additionally, the support element 42 is configured to support at least one pair of the horizontal heat exchanger tubes 28 that are parallel and adjacent to each other in a horizontal direction, e.g. one of the above- mentioned pairs. The support element 42 is configured to be mounted on the vertical support tube 30. Thereby the support element 42 is between the adjacent horizontal heat exchanger tubes 28 of the pair. Referring to examples shown in Figs. 7 to 10, the support element 42 comprises a main body 44 and at least one supporting arm 46 or at least one pair of the supporting arms 46. The main body 44 includes a hollow interior that extends in a vertical direction through the main body 44. The main body 44 is configured to surround the vertical support tube 30 that passes through the hollow interior. The main body N 44 may be in the form of a sleeve.

N - The supporting arm 46 extends outwardly from and substantially perpendicular 3 30 to the main body 44. Each pair of the supporting arms 46 comprises two I supporting arms 46 that extend in two opposite directions with respect to each N other. S Each supporting arm 46 is configured to support at least one of the heat N 35 exchanger tubes 28 in such a way that in a vertical direction a downward movement of the heat exchanger tube 28 is prevented.

Referring to the examples in Figs. 4 and 6, the shape of the hollow interior of the support element 42 may be configured to allow the support element 42 to rotate around a vertical direction about the vertical support tube 30. According to an example shown in Figs. 4 and 8, the shape is circular, or circular in part as in the example of Figs. 6 and 10. Referring to the examples in Figs. 4 and 6, the shape of the hollow interior of the support element 42 may be configured to allow the support element 42 to slide along the vertical support tube 30. According to an example shown in Figs. 4 and 8, the shape is circular, or circular in part as in the example of Figs. 6 and10. Preferably, the rotating movement and/or the sliding movement enables the mounting of and facilitates the installation of the support element 42 and/or the horizontal heat exchanger tubes 28 or are for use during the installation. According to a first example the main body 44 is formed by a circular pipe as shown in Figs. 7 and 8. The main body 44 is made for example from weldable steel. According to the first example each supporting arm 46 is a sheet structure fixed to the main body 44. The supporting arms 46 are made for example from weldable steel. According to a second example the main body 44 is formed by two support element parts as shown in Figs. 9 and 10. Each support element part includes a curved section constituting a part of the main body 44. At least one of the support element parts includes one or more of the supporting arms 46 N integrated to the curved section. The two support element parts are connected N to each other, e.g. by welding, to form the main body 44 and the supporting - arms 46. The hollow interior of the support element 42 is formed between the 3 30 two support element parts. The support element parts are made for example x from weldable steel.

O = Referring to the examples in Figs 3 and 5, when the support element 42 S comprises at least two pairs of the supporting arms 46, the pairs are one after the other in a vertical direction and the supporting arms 46 extend in the above- mentioned two opposite directions on two opposite sides of the support element 42. When the support element 42 comprises two or more of the supporting arms 46 one after the other in a vertical direction, the supporting arms 46 extend in the same direction on a side of the support element 42. According to examples, the supporting arms 46 are on one side of the support element 42 only or on two opposite sides of the support element 42 only. Preferably, the spacing of the supporting arms 46 is matched with the spacing of the horizontal heat exchanger tubes 28 in the heat exchanger 20 or in the above-mentioned elements of the heat exchanger 20, as shown in Figs. 2, 3 and 5.

Referring to Figs 7 and 9, each supporting arm 46 may include a retaining lip at an outer end of the supporting arm 46, the retaining lip extending upwardly from the outer end of the supporting arm 46.

Referring to Figs 7 and 9, each supporting arm 46 may have a recess for supporting from below one of the heat exchanger tubes 28 that is located in the recess. The recess may be rounded.

According to an example, the retaining lip extends to a height that is equal to or less than the radius of the horizontal heat exchanger tube 28 that is supported by the supporting arm 46 and has a circular shape.

According to an example, the outer end of the supporting arm 46 is shaped to engage a matching shape on one of the heat exchanger tubes 28. The supporting arm 46, when connected to the matching shape, supports the heat N exchanger tube 28.

N - Referring to the examples in Figs / and 9, in each pair of the supporting arms 3 30 46, the supporting arms 46 are preferably parallel to each other and in a x vertical direction located at the same height.

O = Referring to Figs. 3 and 5, the heat exchanger 20 may be supported by one S support element 42, or, by at least two support elements 42 on top of each other. In the latter case, the support elements 42 may be separated by a gap or the upper support element 42 rests on the lower support element 42. The one support element 42, the lower support element 42, or the lowest support element 42 may be attached to the vertical support tube 30, for example to prevent the support element(s) 42 from sliding down along the vertical support tube 30. Preferably, the support element 42 is supported by the vertical support tube 30 when being connected to it or by way of another support element 42 or a component attached the vertical support tube 30. Referring to the examples in Figs. 3 and 5, there may be a bracket 48 that is fixed, e.g. by welding, to the vertical support tube 30 below the support element(s) 42. The bracket 48 is adapted to support the support element(s) 42 and to prevent the support element(s) 42 from sliding down along the vertical support tube 30. According to an example, one of the support elements 42 rests on the bracket 48. The bracket 48 may be in the form of a circular ring or sleeve. The support element 42 or the lowermost support element 42 may be fixed, e.g. by welding, to the bracket 48, for preventing the support element 42 from rotating about the vertical support tube 30. Referring to the example in Fig. 9, the support element 42 may be prevented from rotating with respect to the other corresponding support elements 42, around a vertical direction, and/or around the vertical support tube 30. As shown in an example in Fig. 9, for the above-mentioned reasons, the main body 44 of the support element 42 comprises a protrusion or a notch in a lower section and/or in an upper section of the main body 44. The protrusion and/or the notch is adapted to settle against a matching protrusion or a matching N notch of another one of the support elements 42, the other support element 42 N being situated in a vertical direction above or below the support element 42. - The protrusion and the notch are configured to prevent the support element 42 3 30 from rotating, with respect to the other support element 42, around a vertical x direction, and/or the vertical support tube 30.

O = The support element 42 may comprise one or more clamping elements 50 S mounted on the support element 42 for tying one or more horizontal heat exchanger tubes 28 to the support element 42 and/or to prevent the support element 42 from rotating around the vertical support tube 30. The clamping element 50 is preferably detachable.

Referring to the example shown in Figs. 3, 5, 11 and 12, there may be a clamping element 50 mounted on the main body 44 of the support element 42, for the purpose of preventing the support element 42, or the uppermost support element 42, from rotating around the vertical support tube 30. The clamping element 50 may lean against one or two of the horizontal heat exchanger tubes

28. According to an example, as shown in Figs. 3, 5, 11 and 12, the clamping element 50 extends over at least one of the horizontal heat exchanger tubes 28 to at least one of the supporting arms 48 on which the at least one horizontal heat exchanger tube 28 is supported. The clamping element 50 engages the at least one supporting arm 48. According to an example in Figs. 11 and 12, the clamping element 50 comprises a cover part 56 adapted to be mounted on the main body 44. The cover part 56 has an opening 52 through which the vertical support tube 30 extends and at least one skirt part 58 including a notch 54 adapted to engage the supporting arm 28. The clamping element 50 is made for example from weldable steel. The support element 42 may comprise a bracket attached to it and which the clamping element 50, for example the cover part 56, engages. For example, the opening 52 may have a notch that settles on the bracket.

Referring to Figs. 4 and 6, the support element 42 being rotatably mounted on N the vertical support tube 30, the installation of the support element 42 between N the horizontal heat exchanger tubes 28, the removal of the support element 42 - from between the horizontal heat exchanger tubes 28, the installation of the 3 30 heat exchanger 20 or one or more elements of the heat exchanger 20 into the I flue gas passage 60, and the removal of the heat exchanger 20 or one or more N elements of the heat exchanger 20 from the flue gas passage 60 is facilitated. S This facilitation is realized by rotating the support element 42 in such a way N 35 that the supporting arms 48 of the support element 42 reach a position in which they are parallel to the horizontal heat exchanger tubes 28. This, for example,

prevents the supporting arms 48 from colliding with the heat exchanger tubes 28 that are being moved. In this description, the singular form “a”, “an”, and “the” referring to a device or component does not exclude additional or a plurality of corresponding devices or components, unless where specifically specified. In the description, various devices and components may be described as “comprising” other components. The terms “comprise(s)’, “comprising”, ‘include(s)’, “having”, “has”, and variants thereof, are intended to be open- ended phrases that do not exclude the possibility of additional components, unless where specifically specified. The various aspects and embodiments of the present solution disclosed in this description are for the purposes of illustration and are not intended to be limiting. It is intended that the present solution be construed as including all such aspects and embodiments that are covered by the scope of the appended claims.

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Claims

Claims:

1. A support element (42) for supporting at least one horizontal heat exchanger tube (28), the support element (42) being configured to be mounted on a vertical support tube (30), the support element comprising: - a main body (44) including a hollow interior extending in a vertical direction through the main body and being configured to surround the vertical support tube (30) passing through the hollow interior, and - at least one supporting arm (46), wherein the supporting arm extends outwardly from and substantially perpendicular to the main body (44), - wherein each supporting arm (46) is configured to support at least one of the heat exchanger tubes (28) in such a way that in a vertical direction a downward movement of the heat exchanger tube is prevented.

2. The support element of claim 1, wherein the support element (42) comprises: - at least one pair of the supporting arms (46), - wherein in each pair the supporting arms extend in two opposite directions with respect to each other, outwardly from and substantially perpendicular to the main body (44), - wherein each pair is configured to support at least one pair of the horizontal heat exchanger tubes (28) that are parallel and adjacent to each other in a horizontal direction.

3. The support element of claim 1 or 2, wherein the support element comprises at least: N - the first supporting arm (46) or the first pair of the supporting arms N (46), and - - the second supporting arm (46) or the second pair of the supporting 3 30 arms (46), one supporting arm after another in a vertical direction or one pair x of the supporting arms after another pair in a vertical direction.

O = 4. The support element of any one of claims 1 to 3, wherein each supporting S arm (46) has - a recess for supporting from below one of the exchanger tubes (28).

5. The support element of any one of claims 1 to 4, wherein the shape of the hollow interior is configured to allow the support element to rotate around and/or to slide along the vertical support tube (30) that has a circular shape, wherein the support element (42) is adapted to enclose the vertical support tube (30).

6. The support element of any one of claims 1 to 5, wherein the main body (44) comprises - a protrusion or a notch in a lower section and/or in an upper section of the main body, - wherein the protrusion and/or the notch is configured to settle against a matching protrusion, or a matching notch of another corresponding support element situated above or below the support element (42) in a vertical direction, and - wherein the protrusion or the notch is configured to prevent the support element (42) from rotating, with respect to the other corresponding support element, around a vertical direction and/or around the vertical support tube (30).

7. The support element of any one of claims 1 to 6, wherein the support element (42) comprises: - two support element parts, - wherein each support element part includes a curved section constituting a part of the main body (44), and - wherein at least one of the support element parts includes one or more of the supporting arms (46) integrated to the curved section, and N - wherein the two support element parts are connected to each other to N form the main body (44) and the at least one supporting arm (46), wherein the - hollow interior is formed between the two support element parts. S 30 I

8. A system for supporting horizontal heat exchanger tubes (28), the system N comprising: = - a vertical support tube (30), S - one or more support elements (42) according to any one of claims 1 to 7, each support element being mounted on the vertical support tube (30).

9. The system of claim 8, wherein the support element (42) is adapted to rotate around the vertical support tube (30), and wherein the shape of the hollow interior is configured to allow the support element to rotate around a vertical direction about the vertical support tube (30).

10. The system of claim 8 or 9, wherein the support element (42) is adapted to slide along the vertical support tube (30), and wherein the shape of the hollow interior is configured to allow the support element to slide along the vertical support tube (30).

11. The system of any one of claims 8 to 10, wherein the system comprises - two or more of the support elements (42), the support elements being separate and arranged one on top of the other on the vertical support tube (30).

12. The system of any one of claims 8 to 11, wherein the system comprises - a bracket (48) fixed to the vertical support tube (30) below at least one of the support elements (42), - wherein the bracket (48) is configured to support the at least one support element and to prevent the at least one support element from sliding down along the vertical support tube (30).

13. The system of any one of claims 8 to 12, wherein the system comprises - a clamping element (50) mounted on the support element (42) and configured to tie one or more of the horizontal heat exchanger tubes (28) to the support element (42), N - wherein the clamping element (50) is configured to prevent the support N element (42) from rotating around the vertical support tube (30). 3 30 14. A flue gas passage of a boiler (10), comprising: I - walls including a front wall (32) and a back wall (34) enclosing a N passage (60) for hot flue gases, and = - at least one heat exchanger (20) positioned in the passage, S - wherein the heat exchanger includes at least two horizontal heat exchanger tubes (28) that are parallel and adjacent to each other, and

- wherein the heat exchanger is configured to pass heat from hot flue gases flowing inside the passage (60) to a fluid, a gas, or steam flowing inside the heat exchanger tubes, and - wherein the passage (60) further comprises at least one system according to any one of claims 8 to 13, for supporting the heat exchanger.

15. The flue gas passage of claim 14, wherein between the front and back walls the heat exchanger is supported on one or more of the vertical support tubes (30) by way of the one or more support elements (42) on each vertical support tube (30).

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