Structure of plate heat exchanger, its use in exhaust gas heat recovery, and method of recovering heat from exhaust gas

Abstract

The plate heat exchanger structure (1) comprises a flow path structure (2a, 2b) having an inlet connection part (3) and an outlet connection part (4) for a medium flowing through the flow path, at least one plate pack module (5), and a frame structure (6) on which the plate pack module is detachably arranged, wherein the frame structure (6) is arranged as part of the flow path structure. The plate heat exchanger structure (1) is used for exhaust gas heat recovery by arranging the plate heat exchanger structure as part of the exhaust gas flow path.

Description

[Technical field]

[0001] The present invention relates to a plate heat exchanger arrangement according to the independent claims presented below. The present invention also relates to the use of a plate heat exchanger arrangement in exhaust gas heat recovery and to a method for recovering heat from exhaust gases. [Background technology]

[0002] Extracting heat that would normally be lost in venting the exhaust gases significantly increases the overall thermal efficiency of the associated system. The heat can be recovered and used for various heating or cooling requirements, or to generate steam, for example via an ORC system, or to generate electricity. The recovered thermal energy can be utilised for a variety of applications, contributing to reducing energy costs.

[0003] Exhaust gas heat exchangers are an efficient way to recover waste heat from exhaust gases generated during energy generation. Wherever waste heat is generated in exhaust gases, exhaust gas heat exchangers can be used. For example, tubular heat exchangers are commonly used, but they are typically heavy and large in size, making them not applicable to all applications. Maintenance and cleaning of tubular heat exchangers is also typically laborious.

[0004] For this reason, there is a need for heat exchangers in the field of exhaust gas heat recovery that have a compact structure and are easy to clean and service. Summary of the Invention

[0005] The present invention provides a plate heat exchanger, particularly for exhaust gas heat recovery, which overcomes the above-mentioned problems.

[0006] Therefore, the present invention provides a plate heat exchanger structure that has a compact structure and allows easy maintenance and cleaning of the plate pack.

[0007] The invention also provides a plate heat exchanger structure that is easy to modify and scale for different applications, depending on what the recovered heat is planned to be used for. The invention also provides an embodiment in which several separate heat recovery circuits can be configured in the same structure, thus making them easy to place in the exhaust gas flow path.

[0008] To achieve the above objects, the present invention is characterized by what is presented in the appended claims.

[0009] The embodiments and advantages mentioned in the text relate, where applicable, to the structure of the plate heat exchanger, but also to the method, even if not necessarily specifically mentioned, as well as to the use according to the invention.

[0010] A typical plate heat exchanger structure according to the invention comprises a flow path structure formed by the walls of the flow paths and having inlet and outlet connections for the medium flowing in the flow paths, at least one plate pack module and its frame structure, in which the plate pack module is configured to be removable and the frame structure is configured as part of the flow path structure. The typical frame structure comprises a framework formed of vertical support beams at the corners of the frame structure and horizontal support beams connecting the vertical support beams, the side of the framework arranged relative to the flow paths is open, and the walls of the flow path structure are attached to the frame structure. A typical plate pack module of a plate heat exchanger structure according to the invention comprises: - a plate pack formed of rectangular heat exchanger plates arranged one above the other and having openings, the plate pack having a height direction, the plate pack being mounted as plate pairs, the inner sides of the plate pairs being arranged in communication with each other via channels formed by the openings in the heat exchanger plates, - inlet and outlet connections for a heat transfer fluid, said connections being arranged in relation to the flow passages of the plate pack and to the inner sides of the plate pairs; the support end plates disposed at both ends of the plate pack; - The side support plates, which are arranged on the side end faces on both sides of the plate pack, almost cover the side end faces in the height direction of the plate pack, and the plate pack module is arranged in a flow path structure so that the height direction of the plate pack formed of rectangular heat exchange plates is perpendicular to the flow direction of the medium flowing through the flow path, and the width direction of the heat exchange plates becomes the flow direction of the medium flowing through the flow path.

[0011] Typically, the plate heat exchanger structure according to the invention is used in exhaust gas heat recovery. The plate heat exchanger structure according to the invention is applicable for use in any system in which exhaust heat is generated. In an embodiment according to the invention, the plate heat exchanger structure according to the invention is used for exhaust gas heat recovery in power plants or other plants with exhaust gas heat. The compact structure and the possibility of arranging several separate heat recovery circuits in the same structure are particularly useful in ships and vessels. Thus, in an advantageous embodiment, the plate heat exchanger structure according to the invention is used for exhaust gas heat recovery in ships or vessels.

[0012] In a typical method according to the invention for recovering heat from exhaust gas, heat is recovered by arranging a plate heat exchanger structure according to the invention as part of the exhaust gas flow path, whereby the exhaust gas is directed to flow through the flow path structure and plate packs of the plate pack module.

[0013] The plate heat exchanger structure according to the invention provides a compact design due to the rectangular heat exchanger plates used in the plate pack. The plate pack modules detachably arranged in the frame structure facilitate inspection, cleaning and maintenance of the plate pack. The plate pack modules of the plate heat exchanger structure according to the invention are pressure-resistant and self-supporting, which allows the plate heat exchanger structure according to the invention to be easily modified and scaled for different applications, depending on the purpose for which the recovered heat is used. With the plate heat exchanger structure according to the invention, two or more plate pack modules with a frame structure can be easily arranged in a flow path structure.

[0014] The plate heat exchanger structure of the present invention provides efficient utilization of exhaust gas waste heat. By using the present invention, the heat can be recovered and used for various heating and / or cooling requirements via the ORC system, or to generate steam, or to generate more electricity for example.

[0015] The invention is explained in more detail below with reference to the accompanying schematic drawings. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 shows the structure of a plate heat exchanger according to an embodiment of the present invention. [Diagram 2] FIG. 2 shows in more detail a plate pack module of a plate heat exchanger construction according to an embodiment of the invention. [Diagram 3] FIG. 3 shows a schematic cross-section of a plate pack module according to an embodiment of the invention arranged in a frame structure. [Figure 4] FIG. 4 shows a schematic cross-section of a plate pack module according to another embodiment of the invention arranged on a frame structure. [Diagram 5] FIG. 5 shows an embodiment according to the invention in which plate pack modules with four frame structures are arranged side by side in the flow direction of the medium into the flow passages. [Figure 6]FIG. 6 shows an embodiment according to the present invention in which two plate pack modules with a frame structure are placed on top of one another in a flow path structure. [Figure 7] Figure 7 shows a schematic cross-section of an embodiment of the present invention in which two plate pack modules having a frame structure are arranged end-to-end with each other, whereby the inlet and outlet connections of the plate pack modules are on different sides of the flow path structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The structure of the plate heat exchanger of the present invention comprises a flow path structure, at least one plate pack module, and a frame structure in which the plate pack module is removably arranged, and this frame structure is arranged as part of the flow path structure.

[0018] The flow path structure of the plate heat exchanger structure according to the invention is formed by the walls of the flow paths and comprises inlet and outlet connections for the medium flowing through the flow paths. The flow path structure is typically a duct. In a preferred embodiment of the invention, the flow path structure is an exhaust gas flow path, whereby the flow path structure comprises an inlet and an outlet connection for the exhaust gas flow. According to an embodiment of the invention, the inlet and outlet connections of the flow path structure of the structure are used to connect the inventive plate heat exchanger structure to an exhaust gas duct for supplying the inventive plate heat exchanger structure with hot exhaust gas and also to connect the inventive plate heat exchanger structure to an exhaust gas duct for conveying the cooled exhaust gas leaving the heat exchanger structure. In an embodiment according to the invention, the flow path structure may be an exhaust gas duct or another duct in which the plate heat exchanger structure is arranged and is therefore part of the flow path structure of the exhaust gas duct. In this case, the inlet and outlet connections of the flow path structure refer to the inlet and outlet of the exhaust gas flow path or another flow path.

[0019] In this disclosure, exhaust gas refers to gas generated as a result of the combustion of fuel or other materials. Exhaust gas leaves the system after an energy exchange or conversion process, such as combustion gas from a diesel engine, boiler, gas turbine, incinerator, or corresponding system in other power plants. Exhaust gas can also be called flue gas. Exhaust gas is conveyed from the combustion system through a duct, and the exhaust gas heat can be recovered by placing the plate heat exchanger structure according to the present invention in the exhaust gas duct.

[0020] The plate pack module according to the invention comprises a plate pack, which is based on the plate pack structure used in plate and shell type heat exchangers. The plate pack is formed of heat exchanger plates with openings arranged one above the other. The heat exchange plates are attached to each other as plate pairs. Each plate pair is typically formed of two heat exchange plates that are attached and preferably welded together at least at their periphery. Each heat exchange plate has at least two openings for the flow of a heat transfer fluid. Adjacent plate pairs are attached to each other by mounting, preferably welding the openings of two adjacent plate pairs to each other. The inner parts of the plate pairs are arranged in relation to each other via the flow paths formed by the openings of the heat exchange plates. Thus, the heat transfer fluid can flow from one plate pair to another via the openings. Inlet and outlet connections for the heat transfer fluid are arranged on the end plates of the plate pack for conducting the heat transfer fluid to and from the plate pack. The inlet and outlet connections for the heat transfer fluid are arranged in connection with the internal parts of the plate pack, i.e. with the internal parts of the plate pairs of the plate pack, so that a circuit is formed between the inlet and outlet connections for the heat transfer fluid. In the structure of the plate heat exchanger according to the invention, the medium flowing in the flow passage, preferably the exhaust gas flow passage, is arranged to flow in the space between the plate pairs. The inlet and outlet connections for the medium flowing in the flow passage, for example for the exhaust gas, are arranged in relation to the flow passage structure and in relation to the space between the plate pairs of the plate pack. In other words, the medium flowing in the flow passage, for example the exhaust gas, flows inside the flow passage structure and also in the space between the plate pairs of the plate pack. The heat transfer fluid flowing inside the plate pack cannot mix with the medium flowing in the flow passage structure. The heat transfer fluid flows in every other plate space and the exhaust gas flows in every other plate space of the plate pack. The heat transfer fluid can be a gas or a liquid involved in the heat transfer.

[0021] The plate packs of the plate pack module are formed of rectangular heat exchange plates. In a preferred embodiment of the present invention, the plate packs of the plate pack module are formed of rectangular heat exchange plates with curved ends. In other words, the plate packs according to the embodiment of the present invention are formed of heat exchange plates having a rectangular shape formed by two semi-ellipses. The curved ends of the heat exchange plates improve the pressure resistance of the plate pack and also facilitate welding of the plate pack. The heat exchange plates have a length direction and a width direction. The length direction of a rectangular heat exchange plate refers to the direction of the longest side of the plate. Correspondingly, the length direction refers to the direction of the plate from one curved end to another curved end. The width direction of the heat exchange plate is a direction perpendicular to the length direction. The width direction is usually shorter than the length direction, because the heat exchange plate is a rectangular plate, i.e., the plate pack is formed of slim heat exchange plates. The openings of the heat exchange plate are arranged at both ends of the rectangular plate heat exchange plate, and the openings form a flow path for the heat transfer fluid flowing inside the plate pair.

[0022] As mentioned above, the plate pack is formed by arranging plate pairs of plate heat exchange plates one above the other. In the present disclosure, the height direction of the plate pack refers to the direction of the plate pack formed by the plate pairs on top of each other, i.e. the height of the stack of plate pairs. The plate pack has the same length and width directions as the heat exchange plates. The plate pack has a major side defined by the height and length directions of the plate pack and a thin side end face on which the end is formed, and the curved end of the heat exchange plate is preferably defined by the height and width directions of the plate pack. The side end face is substantially perpendicular to the major side face.

[0023] In a plate pack module, supporting end plates are arranged at both ends of the height of the plate pack. The supporting end plates have substantially the same outer shape as the heat exchanger plates, but they are typically thicker than the heat exchanger plates.

[0024] The plate pack module also includes side support plates arranged on both side end surfaces of the plate pack, and the side support plates substantially cover the side end surfaces in the height direction of the plate pack. The side end surfaces of the plate pack refer to the side end surfaces of the plate pack formed from the ends of the heat exchange plates, and are typically formed from the curved ends of the heat exchange plates. In an embodiment of the present invention, the side support plates of the plate pack extend from the one support end plate to the other support end plate of the plate pack, and the side support plates substantially cover the side end surfaces of the plate pack in the height direction of the plate pack. The side support plates may be formed as one single part, or may be formed of two or more parts. The side support plates make the plate pack module structure stronger, and they may function as flow guides by preventing bypass flow of exhaust gas in the flow path structure. According to one embodiment of the present invention, the side support plates are at least partially folded against the large side surfaces of the plate pack. As a result, the gas flow can be efficiently guided through the plate pack in the center of the flow path.

[0025] Furthermore, the plate pack module comprises inlet and outlet connections for the heat transfer fluid, which connections are arranged in relation to the flow paths and the inner sides of the plate pairs of the plate pack.

[0026] In a preferred embodiment of the invention, the plate pack module is fully welded and the plate pack module itself is a pressure-resistant self-supporting structure.

[0027] In an embodiment of the invention, the plate pack may include an inner tube structure and a stopper plate or plates arranged in the flow paths of the plate pack, which allows for multiple paths to be arranged in the plate pack.

[0028] The plate heat exchanger structure further comprises a frame structure in which the plate pack module is removably arranged. The frame structure according to the invention is a framework that is set around the plate pack module. It comprises support beams on all sides of the plate pack module, typically at the corners of the plate pack module. According to the invention, the frame structure comprises a framework formed of vertical support beams at the corners of the frame structure and horizontal support beams connecting the vertical support beams. When the plate pack module is arranged in the frame structure, the support beams go around the corners of the plate pack module. The side of the framework arranged against the flow path is open to allow the exhaust gas to flow through the plate pack module. The frame structure comprises a cover plate that closes a side of the frame structure, the cover plate being the side opposite to the side on which the plate pack module can be arranged in the frame structure.

[0029] According to an embodiment of the present invention, the frame structure may further comprise additional flow guide plates arranged on the frame structure, preferably at corners of the frame structure for guiding the flow of the exhaust gas through the plate pack in the center of the flow passage.

[0030] According to an exemplary embodiment of the invention, the plate pack module further comprises an end plate at one end of the plate pack, by means of which the plate pack module is removably fixed to a flange of the frame structure. The end plate is attached to a supporting end plate of the plate pack. Thus, the plate pack module can be easily removed from the plate heat exchanger arrangement and removed from the frame structure, for example for inspection, cleaning or other maintenance.

[0031] In a plate heat exchanger structure according to an embodiment of the invention, the frame structure of the plate pack module and the flow path structure attached to the frame structure form the framework of the plate heat exchanger structure of the invention. According to the invention, the frame structure is arranged as part of the flow path structure. In a typical embodiment of the invention, the flow path structure of the plate heat exchanger structure is attached to the frame structure of the plate pack module. According to one embodiment of the invention, the walls of the flow path structure are attached to the frame structure. Thus, the frame structure of the plate pack module forms part of the flow path structure.

[0032] In a typical embodiment according to the invention, the plate pack module is arranged in the flow path structure such that the width direction of the heat exchanger plates is the flow direction of the medium flowing in the flow path, such as the flow direction of the exhaust gas. That is to say, the plate pack module is arranged in the flow path structure such that the height direction of the plate pack formed of rectangular heat exchanger plates is perpendicular to the flow direction of the medium flowing in the flow path, such as the exhaust gas, and the medium flowing in the flow path flows through the plate pack in the width direction of the plate pack. The length of the movement of the exhaust gas flow through the plate pack is therefore arranged to be short. This is advantageous since the exhaust gas is a product of combustion and contains fine particles and other undesirable substances, and therefore the exhaust gas can cause the accumulation of fine particles in the plate pack and thus weaken the heat transfer. This can be avoided by the plate pack module according to the invention. Also, the pressure loss of the gas is low when flowing through the plate pack formed of rectangular heat exchanger plates, and the length of the flow of the exhaust gas through the plate pack is arranged to be short. Correspondingly, the flow direction of the heat transfer fluid inside the plate pack can be arranged to be longer, since it flows through the plate pack in the length direction of the plate and therefore the heat transfer is efficient throughout the plate pack.

[0033] According to the invention, the plate heat exchanger structure comprises at least one plate pack module arranged as part of the flow path structure and its frame structure. Thus, in one embodiment of the invention, the plate heat exchanger structure comprises one plate pack module and its frame structure, which is arranged as part of the flow path structure. In another embodiment according to the invention, the plate heat exchanger structure comprises two or more plate pack modules with their frame structures, which are arranged in the flow path. In a preferred embodiment according to the invention, each plate pack module comprises its own frame structure. Thus, it is easy to scale and modify the structure depending on the required functions. The frame structures can be attached to each other.

[0034] Two or more plate pack modules with their frame structures can be arranged in the structure of the plate heat exchanger in many ways. In one embodiment, two or more plate pack modules with their frame structures are arranged side by side in the flow direction of the fluid into the flow path. In another embodiment, two plate pack modules with their frame structures are arranged in the flow path one on top of the other. The flow path can include plate pack modules arranged in the flow direction of the medium into the flow path and / or one on top of the other into the flow path. According to a preferred embodiment of the invention, the plate pack modules are arranged in a flow path structure such that the height direction of the plate pack formed of rectangular heat exchanger plates is perpendicular to the flow direction of the medium flowing in the flow path, such as exhaust gas, and the medium flowing in the flow path flows through the plate pack in the width direction of the plate pack.

[0035] In one embodiment, two plate pack modules with their frame structures are placed end to end with each other, whereby the inlet and outlet connections of the plate pack modules are on different sides of the flow channel structure. Also, in this embodiment, the flow channel may include plate pack modules side by side and / or one on top of the other in the flow direction of the medium into the flow channel.

[0036] The plate heat exchanger structure according to the invention can be used in any system in which waste heat is generated, typically by exhaust gas. As mentioned above, the structure according to the invention comprises one, two or several plate pack modules, the frame structure of which is arranged in a flow path. In the method according to the invention for recovering heat from exhaust gas, the heat is recovered by arranging the plate heat exchanger structure according to the invention as part of the exhaust gas flow path, whereby the exhaust gas is guided to flow through the plate packs of the plate pack module.

[0037] Detailed Description of the Drawings Figure 1 shows a plate heat exchanger structure according to an embodiment of the present invention, and Figure 2 shows in more detail a plate pack module of the plate heat exchanger structure shown in Figure 1. Figures 3 and 4 show schematic cross-sections of a plate pack module according to an embodiment of the present invention.

[0038] The plate heat exchanger structure 1 according to an embodiment of the invention comprises a flow path structure having an inlet connection 3 and an outlet connection 4 for a medium flowing through the flow paths. In Fig. 1, the flow path structure is formed of two parts 2a, 2b attached to a frame structure 6. The plate heat exchanger structure 1 shown in Fig. 1 comprises one plate pack module 5 and a frame structure 6 in which the plate pack module 5 is removably arranged. The frame structure 6 was arranged as a part of the flow path structure.

[0039] The plate pack module 5 according to the invention, shown in detail in Figure 2, comprises a plate pack 7 formed of rectangular heat exchanger plates with openings arranged on top of one another. In the plate pack 7 according to the invention, the heat exchanger plates are attached to one another in plate pairs, the inner sides of which are arranged in relation to one another via the flow channels 20, 21 formed by the openings in the heat exchanger plates as shown in Figures 3 and 4. The plate pack module 5 comprises inlet connections 8 and outlet connections 9 for the heat transfer fluid, which connections are arranged in relation to the flow channels 20, 21 and the inner sides of the plate pairs of the plate pack.

[0040] The plate pack module 5 also comprises supporting end plates 10 arranged at both ends of the plate pack 7. Typically, the plate pack module 5 further comprises an end plate 12 at one end of the plate pack, by means of which the plate pack module is detachably fixed to a flange 15 of the frame structure. Only one supporting end plate, namely the supporting end plate 10, is visible in Figures 2 to 4. Note that the other supporting end plate of the plate pack was arranged between the plate pack 7 and the end plate 12. The supporting end plate and the end plate 12 are typically attached to each other, but can also be made as one piece.

[0041] The plate pack module 5 also includes side support plates 13, 14 arranged on both side end faces of the plate pack 7, so that the side support plates 13, 14 cover almost the entire side end face in the height direction of the plate pack. The "height direction of the plate pack" refers to the direction of the plate pack in which the plate pairs are formed on top of each other, i.e., the height of the stack of plate pairs. Typically, the side support plates 13, 14 of the plate pack extend from one support end plate 10 to the other support end plate of the plate pack.

[0042] In FIG. 2, the side support plates 13, 14 are at least partially bent against the major side of the plate pack 7. The major side of the plate pack is determined by the height and length of the plate pack, which are opposed to the flow path. That is, the height of the plate pack formed of rectangular heat exchanger plates is perpendicular to the flow direction of the medium, such as exhaust gas, flowing through the flow path. This means that the plate pack module 5 is arranged in a flow path structure such that the width direction of the heat exchanger plates is in the flow direction of the medium, such as exhaust gas, flowing through the flow path.

[0043] The frame structure 6 of the plate heat exchanger structure 1 according to the present invention is composed of a framework formed of vertical support beams at the corners of the frame structure and horizontal support beams connecting the vertical support beams, as can be seen from Fig. 2. The frame structure 6 is a framework set around the plate pack module 5. The frame structure 6 may further comprise one or more flow guide plates 16, 17, 18 arranged on the frame structure. Typically, the flow guide plates 16, 17, 18 are arranged at the bottom and / or top of the frame structure 6 in the height direction of the flow path.

[0044] As shown in Figure 2, the side of the framework that is positioned relative to the flow path is open to allow the exhaust gas to flow through the plate pack module. Typically, the frame structure 6 is provided with a cover plate 19 for closing the side of the frame structure, which is the side opposite to the side on which the plate pack module 5 can be placed in the frame structure.

[0045] The frame structure is part of the flow channel structure, as shown in Figures 1 and 2. The walls of the flow channel structures 2a, 2b were attached to a frame structure 6.

[0046] Figures 3 and 4 provide several embodiments of flow arrangements within the plate pack 7. Figure 4 shows an internal tubular structure 40 located within the flow passage 20 and a stopper plate 41 located within the flow passage 21 to provide multiple paths for the flow of heat transfer fluid within the plate pack.

[0047] 5 to 7 show some embodiments according to the present invention, in which the plate heat exchange structure comprises two or more plate pack modules.

[0048] 5 shows an embodiment according to the invention, in which four plate pack modules 22, 23, 24, 25 together with their frame structure are arranged side by side. They can be arranged in the flow path structure so that they are aligned in the flow direction of the medium in the flow path. The plate pack modules are also arranged in the flow path structure so that the height direction of the plate pack formed by rectangular heat exchanger plates is perpendicular to the flow direction of the medium, such as exhaust gas, flowing in the flow path.

[0049] Figure 6 shows a plate heat exchanger structure 1 according to an embodiment of the invention, in which two plate pack modules 26, 27 with a frame structure are arranged one above the other in a flow path structure. The flow path structures 2a, 2b are attached to the frame structure of the plate pack modules. The height direction of the plate packs of the plate pack module is perpendicular to the flow direction of the medium into the flow paths. The plate heat exchanger structure 1 further comprises an inlet connection 3 and an outlet connection 4 for the medium flowing in the flow paths.

[0050] FIG. 7 shows an embodiment according to the invention, in which two plate pack modules 28, 29 with frame structures are arranged end to end with each other, whereby the inlet connections 33, 35 and the outlet connections 32, 34 of the plate pack modules are arranged on different sides of the flow path structure. In FIG. 7, two other plate pack modules 30, 31 with frame structures are arranged below the plate pack modules 28, 29. Also, the plate pack modules 30, 31 with frame structures are arranged end to end with each other, whereby the inlet connections 37, 39 and the outlet connections 36, 38 of the plate pack modules are arranged on different sides of the flow path structure. All frame structures are attached to each other to form a compact plate heat exchanger structure.

Claims

1. A plate heat exchanger structure (1), comprising: a channel structure formed in the wall of the channels (2a, 2b) and having inlet and outlet connections (3, 4) for the medium flowing through the channels (2a, 2b); at least one plate pack module (5); and a frame structure (6) on which the plate pack module (5) is removably arranged, the frame structure (6) being arranged as a part of a flow path structure, the frame structure (6) having a framework composed of vertical support beams formed at corners of the frame structure (6) and horizontal support beams connecting the vertical support beams, the side of the framework arranged relative to the flow paths (2a, 2b) being open, and the walls of the flow paths (2a, 2b) being attached to the frame structure (6), The plate pack module (5) a plate pack (7) formed of rectangular heat exchanger plates having openings and arranged one above the other, so that the plate pack (7) has a height direction, in which the heat exchange plates are attached to each other as plate pairs, and inner sides of the plate pairs are arranged to be connected to each other via flow paths (20, 21) formed by the openings in the heat exchange plates; inlet connections (8) and outlet connections (9) for a heat transfer fluid, the inlet connections (8) and outlet connections (9) being arranged connecting the flow paths (20, 21) with the inner sides of the plate pairs of the plate pack (7); Support end plates (10) disposed at both ends of the plate pack (7); and side support plates (13, 14) arranged on both side end surfaces of the plate pack (7), thereby substantially covering the side end surfaces of the plate pack (7) in the height direction of the plate pack (7), The plate pack module (5) is arranged in the flow path structure so that the height direction of the plate pack (7) formed of rectangular heat exchanger plates is perpendicular to the flow direction of the medium flowing through the flow paths (20, 21), thereby making the width direction of the heat exchanger plates the flow direction of the medium flowing through the flow paths (20, 21).

2. 2. The structure (1) according to claim 1, characterized in that the rectangular heat exchanger plates have curved edges.

3. 3. The structure (1) according to claim 1 or 2, characterized in that the plate pack module (5) further comprises an end plate (12) at one end of the plate pack (7), by which the plate pack module (5) is removably fixed to a flange (15) of the frame structure (6).

4. 3. A structure (1) according to claim 1 or 2, characterized in that the side support plates (13, 14) are at least partially bent relative to the major sides of the plate pack (7).

5. 3. A structure (1) according to claim 1 or 2, characterized in that the side support plates (13, 14) of the plate pack (7) extend from one of the support end plates (10) to the other support end plate (10) of the plate pack (7).

6. 3. A structure (1) according to claim 1 or 2, characterized in that the plate pack module (5) is fully welded.

7. 3. The structure (1) according to claim 1 or 2, characterized in that the frame structure (6) further comprises flow guide plates (16, 17, 18) arranged on the frame structure (6).

8. 3. The structure (1) according to claim 1 or 2, characterized in that two or more plate pack modules (22, 23, 24, 25) comprising the frame structure (6) are arranged side by side in the flow direction of the medium into the flow paths (20, 21).

9. 3. The structure (1) according to claim 1 or 2, characterized in that two or more plate pack modules (26, 27) having the frame structure (6) are arranged side by side, one on top of the other, in the flow path (20, 21).

10. 3. The structure (1) according to claim 1 or 2, characterized in that two plate pack modules (28, 29) having the frame structure (6) are arranged end to end with each other, so that the inlet and outlet connections (32, 33) of the first plate pack module (28) and the inlet and outlet connections (34, 35) of the second plate pack module (29) are on different sides of the flow path structure.

11. A method for recovering heat from exhaust gas, characterized in that the plate heat exchanger structure (1) described in claim 1 or 2 is arranged as part of the exhaust gas flow path to recover heat.

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