WO2007059770A1

WO2007059770A1 - Heat exchanger module and heat exchanger system

Info

Publication number: WO2007059770A1
Application number: PCT/DK2006/000588
Authority: WO
Inventors: Preben Jensen
Original assignee: Eurotec London Ltd
Priority date: 2005-11-25
Filing date: 2006-10-20
Publication date: 2007-05-31
Also published as: DK1957924T3; ATE520001T1; PT1957924E; DK200600428A; ES2376816T3; EP1957924B1; EP1957924A1

Abstract

The present invention relates to a heat exchanger module and a heat exchanger system for transfer of heat between different media, in particular a heat exchanger module for preheating materials that are to be employed in a process for biogas production, such as liquid manure, industrial process water, sludge and/or ooze. A heat exchanger module is provided, wherein the heat exchanger module has walls and comprises a first flow channel positioned in thermal contact with a second flow channel for heat exchange between a first fluid flowing in the first flow channel and a second fluid flowing in the second flow channel, and wherein a first section of the first flow channel abuts at least three second sections of the second flow channel. Further a heat exchanger system is provided, comprising one or more heat exchanger modules according to the invention.

Description

HEAT EXCHANGER MODULE AND HEAT EXCHANGER SYSTEM FIELD OF THE INVENTION

The present invention relates to a heat exchanger module and a heat exchanger system for transfer of heat between different media, in particular a heat exchanger module for preheating materials that are to be employed in a process for biogas production, such as liquid manure, industrial process water, sludge and/or ooze.

BACKGROUND OF THE INVENTION

In many biogas systems the biological material entering the system has a low temperature and requires heating before entering process tanks operating at different temperatures. On the other hand, material from the process tanks may have a high temperature and requires a lowering of the temperature.

Heat exchangers employing a heat transporting medium, such as water, for transfer of heat between two reservoirs by circulating the heat transporting medium in a closed loop submerged in the two reservoirs are known. Such heat exchangers usually have a low efficiency.

Counterflow heat exchangers for liquid manure are often built as tube in tube and require frequent cleaning. Cleaning of these heat exchangers is usually very difficult due to the construction or involves a heavy wear on the material of the heat exchanger when using acid. SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a heat exchanger that has a high efficiency and that is easy to maintain.

It is a further object of the present invention to provide a heat exchanger that is easily adjustable to handle different operating parameters. It is among the objects of the present invention to provide a heat exchanger capable of operating under high pressures.

Accordingly, a heat exchanger module is provided, wherein the heat exchanger module has walls and comprises a first flow channel positioned in thermal contact with a second flow channel for heat exchange between a first fluid flowing in the first flow channel and a second fluid flowing in the second flow channel. A first section of the first flow channel abuts at least three second sections of the second flow channel. Further, a heat exchanger system is provided, comprising one or more heat exchanger modules as described herein. Preferably, the heat exchanger system comprises a first heat exchanger module and a second heat exchanger module that are interconnected to form a first flow channel and a second flow channel. Preferably, the first flow channel and the second flow channel have a substantially uniform cross section through the heat exchanger module.

In a preferred embodiment of the heat exchanger module, a second section of the second flow channel abuts at least three first sections of the first flow channel.

Preferably, the walls in the heat exchanger module form a plurality of cavities to form at least two flow channels. For example, first cavities may be connected via first connectors forming a first flow channel and second cavities may be connected via second connectors forming a second flow channel. A cavity may form a section of the first flow channel or the second flow channel.

Preferably, the first flow channel and the second flow channel have common walls to improve heat exchange between fluids in the respective channels. For example, a first section of the first flow channel may have a common wall with at least three different second sections of the second flow channel.

Preferably, heat exchanger module has a body with walls including a first outer wall, a second outer wall, a third outer wall, a fourth outer wall, a first end wall, and a second end wall. Further, the heat exchanger module may comprise inner walls forming a plurality of cavities or sections of flow channels in the body of the heat exchanger module. Preferably, an inner wall forms a common wall between a first section and a second section of the respective flow channels.

The heat exchanger module may have a first port and a second port. The first port may form an inlet and/or an outlet at an end of the first flow channel, and the second port may form an inlet and/or outlet at the other end of the first flow channel.

Further, the heat exchanger module may comprise a third port and a fourth port. The third port may form an inlet and/or an outlet for the second flow channel, and the fourth port may form an inlet and/or an outlet for the second flow channel. The ports may have module connectors, e.g. fittings, for coupling the heat exchanger module to other heat exchanger modules and or external units such as a cleaning system or containers holding first and second fluids. Preferably, the module connectors when intercoupling heat exchanger modules have a cross section corresponding to the cross section of the sections of the flow channels, which they communicate or connect.

Preferably, the first sections of the first flow channel are tubular and second sections of the second flow channel are tubular. Preferably, the first sections and the second sections extend along a straight first axis having a length from about 0.5 m to about 10 m. In a preferred embodiment of the present invention, the sections have a length of about 3 m.

In an embodiment of the present invention, the walls of the heat exchanger module form a first flow channel with a polygonal cross section. In a preferred embodiment of the present invention, the walls of the heat exchanger module form a first flow channel with first sections having a four-sided cross section.

In an embodiment of the present invention, the walls of the heat exchanger module form a second flow channel with a polygonal cross section. In a preferred embodiment of the present invention, the walls of the heat exchanger module form a second flow channel with second sections having a four-sided cross section.

The sections of the respective flow channels may have a substantially polygonal cross section with side lengths from about 10 mm to about 200 mm, such as from about 30 mm to about 100 mm, e.g. about 50 mm. Preferably, the sections have a four-sided cross section, e.g. a rectangular cross section and/or a square cross section, with side lengths from about 10 mm to about 200, preferably from about 25 mm to about 100 mm, more preferably from about 30 mm to about 60 mm, such as about 40 mm or about 50 mm.

The first and second flow channel may be dimensioned, such that a fluid flow from about 0.8 m/s to about 1.7 m/s can be obtained in the flow channels. In a preferred embodiment of the present invention, one or more of the sections of the flow channels, preferably all, have a square cross section with a side length from about 30 mm to about 100 mm, such as about 40 mm, about 50 mm, about 60 mm, about 70 mm, or about 80 mm.

In another preferred embodiment of the present invention, the sections of the flow channels have a rectangular cross section, e.g. having the dimensions 30 mm x 40 mm or 40 mm x 50 mm.

Preferably, the first sections and the second sections of the heat exchanger module are alternately arranged in two columns including a first column and a second column such that a first section in the first column abuts two second sections in the first column and one second section in the second column. Thus, a first section in the first column may have a common inner wall with a second section in the first column, a common inner wall with another second section in the first column, and a common inner wall with a second section in the second column. Preferably, each section is delimited by or defined by at least a part of an outer wall.

The heat exchanger module may comprise first connectors. The first connectors may connect first sections to form the first flow channel or at least a part thereof.

Furthermore, the heat exchanger module may comprise second connectors. The second connectors may connect second sections to form the second flow channel or at least a part thereof.

In a preferred embodiment of the present invention, the connectors are welded to the outer walls of the heat exchanger module thereby connecting sections of the respective flow channels through openings in the outer walls. Preferably, the openings in the outer walls are rectangular and/or quadratic having a cross section corresponding to the cross section of the sections for provision of substantially uniform flow channels. In an embodiment, the connectors are secured in threaded engagement with the walls. In an embodiment of the present invention, the connectors may connect sections of the respective flow channels through openings in the end walls.

Preferably, the first and/or the second connectors have a cross section corresponding to the cross section of the sections which they communicate or connect. Thereby drop of pressure around the connector may be minimized or substantially avoided. Thus, the connectors may have a polygonal cross section with a side length from about 30 mm to about 100 mm, such as a square cross section with a side length from about 30 mm to about 100 mm, such as about 40 mm, about 50 mm, about 60 mm, about 70 mm, or about 80 mm.

Preferably, the connectors are positioned near or at the ends of the first and second sections.

Further, the heat exchanger module may have one or more cleaning holes. Preferably, one or more cleaning holes are provided for each of the cavities forming the sections of the flow channels. In a preferred embodiment, a cleaning hole for each of the cavities forming the sections of the flow channels is provided, e.g. in the first end wall of the heat exchanger module. More preferably, a cleaning hole for each of the cavities forming the sections of the flow channels may further be provided in the second end wall of the heat exchanger module. The one or more cleaning holes may comprise an engagement member, e.g. a threading or a bayonet socket that may be adapted for engagement with a plug member. The one or more cleaning holes provide user access to the different sections of the heat exchanger thereby facilitating manual cleaning or removal of blockages in the flow channel. Further, the heat exchanger module may comprise one or more plug members for sealing the one or more cleaning holes. The one or more plug members comprise an engagement member, e.g. a threading or a bayonet socket, for detachable engagement with the engagement member of a cleaning hole.

It is an important advantage of the present invention that a user has easy access to the different sections of the flow channels for convenient removal of any blockages that may arise during use. The plug members are readily detachable and mountable.

Preferably, the heat exchanger module is made of stainless steel, such as AISI 304 or AISI 316, however any other suitable steel type may be used.

Preferably, the heat exchanger module is made of an acid-resistant steel type. Hereby cleaning of the heat exchanger with acidic fluids is rendered possible.

In an embodiment suitable for non-aggressive fluids, at least a part of the heat exchanger module, e.g. the inner walls and/or the outer walls, may be made of a metal having high thermal conductivity compared to stainless steel, such as black steel, aluminum, or copper. In an embodiment, the walls may be coated with an acid resistant material.

In an embodiment of the present invention, first fluid having a first inlet temperature is pumped into the first flow channel through the first port, passes the first flow channel while exchanging heat with fluid in the second flow channel, and leaves the first flow channel having a first outlet temperature through the second port. At the same time, a second fluid having a second inlet temperature may be pumped into the second flow channel through the third port, passing the second flow channel while exchanging heat with fluid in the first flow channel, and leaving the second flow channel having a second outlet temperature through the fourth port.

The heat exchanger module is in particular adapted for heat exchange between liquid manure; however, the fluids may be any fluids, such as liquid manure, sludge, water in liquid and gaseous form, oil, natural gas, or other fluids.

It is an important advantage of the present invention that the heat exchanger due to its construction is compact and takes up little space compared to the amount of heat transferred. It is an important advantage of the present invention that the heat exchanger is able to transfer large amounts of heat between the fluids in the flow channels.

It is a further advantage of the present invention that cleaning of the heat exchanger module is easy and can be performed without destroying, e.g. cutting, the heat exchanger module.

The walls of the heat exchanger module may have a thickness in the range from about 0.5 mm to about 20 mm, preferably from about 1 mm to about 10 mm. In a preferred embodiment of the present invention, the walls of the heat exchanger have a thickness from about 2 mm to about 5 mm, e.g. about 3 mm or about 4 mm. If the thickness of the walls is too small, a high pressure may not be employed, and if the thickness of the walls is too large, the transfer of heat between the first and second flow channel is reduced.

It may be desired to employ a high pressure in the flow channels. If the first pressure in the first flow channel and the second pressure in the second flow channel are substantially the same, or the pressure difference between the first flow channel and the second flow channel is small, e.g. less than 3 bar, the thickness of the inner walls of the heat exchanger module can be small, such as around 1 mm, thereby obtaining improved heat exchange between the fluids.

The heat exchanger module may further comprise a casing. The casing supports and strengthens the outer walls to increase the possible operating pressures of the heat exchanger module. The heat exchanger module with or without a casing may operate with fluids at a high pressure, e.g. up to 12 bar or more.

The heat exchanger system according to the present invention may comprise one or more heat exchanger modules as described herein, such as two, three, four, five, ten, twenty, fifty or more heat exchanger modules. In a preferred embodiment, the heat exchanger system comprises a first heat exchanger module and a second heat exchanger module as described herein. Preferably, the heat exchanger system comprises a frame carrying the one or more heat exchanger modules. Further, the heat exchanger system may comprise a plurality, e.g. two three, four or more insulation elements for insulation of the heat exchanger modules. The insulation elements may be attached to the frame, e.g. by one or more hinges and/or adapted to support on the frame.

In the heat exchanger system, one or more ports functioning as inlet/outlet of a flow channel may be provided with fittings, e.g. a T-piece, to allow easy coupling, e.g. via valves, of the flow channel to different fluid loops, such as a fluid loop with liquid manure and a fluid loop with cleaning fluid.

Preferably, the heat exchanger system according to the invention comprises one or more module connectors, such as fittings, that connect ports of the heat exchanger modules according to a desired configuration of the heat exchanger system, e.g. depending on the number of fluids to be heat exchanged, number of heat exchanger modules, etc.

Preferably, the module connectors have a cross section corresponding to the cross section of the sections of the heat exchanger modules, which they communicate or connect. Thereby drop of pressure around the module connector may be minimized or substantially avoided. Thus, the module connectors may have a polygonal cross section with a side length from about 30 mm to about 100 mm, such as a square cross section with a side length from about 30 mm to about 100 mm, such as about 40 mm, about 50 mm, about 60 mm, about 70 mm, or about 80 mm. Preferably, first fluid in a first section flows in the opposite direction of the flow of the second fluid in two adjacent second sections.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in further detail with reference to the enclosed drawings, wherein Fig. 1 is a perspective view of an embodiment of a heat exchanger module according to the present invention,

Fig. 2 is another perspective view of the embodiment illustrated in Fig. 1 ,

Fig. 3 shows a perspective cross section of the heat exchanger module illustrated in Fig. 1, Fig. 4 is a side view of a side of the heat exchanger module illustrated in

Fig. 1 ,

Fig. 5 is a side view of the opposite side of the heat exchanger module illustrated in Fig. 1 ,

Fig. 6 shows the side view of Fig. 5 omitting parts of the heat exchanger module,

Fig. 7 schematically illustrates a cross section of the heat exchanger module of Fig. 1 Fig. 8 schematically illustrates a cross section of a heat exchanger module according to the present invention,

Fig. 9 schematically illustrates a cross section of a heat exchanger module according to the present invention, Fig. 10 schematically illustrates an embodiment of a heat exchanger system according to the invention,

Fig. 11 schematically illustrates operation of the heat exchanger system shown in Fig. 10, and

Fig. 12 schematically illustrates operation of an embodiment of a heat exchanger system according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Figs. 1-7 schematically show a preferred embodiment of a heat exchanger module according to the present invention. The heat exchanger module 2 has walls and comprises a first flow channel positioned in thermal contact with a second flow channel for heat exchange between a first fluid flowing in the first flow channel and a second fluid flowing in the second flow channel. Further, a first section of the first flow channel abuts at least three second sections of the second flow channel, e.g. the first section 6Q abuts the second sections 14C, 14D, and 14N. Further, a second section of the second flow channel abuts at least three first sections of the first flow channel, e.g. the second section 14L abuts the first sections 6I, 6J, and 6S.

A first port 4 and a second port 8 in the heat exchanger module function as inlet/outlet to the first flow channel. First sections 6A, 6B, 6C, 6D, 6E, 6F, 6G, 6H, 6I, 6J, 6K, 6L₁ 6M, 6N, 60, 6P, 6Q, 6R, 6S, 6T and first connectors 1OA, 1OB, 1OC, 1OD, 1OE, 10F, 10G, 10H, 101, 10J, 10K, 10L, 10M, 10N, 10O, 10P, 10Q, 10R, 10S form the first flow channel. A first connector connects two first sections of the first flow channel, e.g. the first connector 10A connects the first sections 6A and 6B, the first connector 10B connects the first sections 6B and 6C, etc.

The first sections and the second sections extend along a straight first axis A and having a length of about 3 m.

A third port 12 and a fourth port 16 function as an inlet/outlet to the second flow channel. Second sections 14A, 14B, 14C, 14D, 14E, 14F, 14G, 14H, 141, 14J, 14K, 14L, 14M, 14N, 14O, 14P, 14Q, 14R, 14S, 14T and second connectors 18A, 18B, 18C, 18D₁ 18E₁ 18F, 18G, 18H₁ 181, 18J, 18K, 18L, 18M₁ 18N, 180, 18P, 18Q, 18R₁ 18S form the second flow channel, each second connector connecting two second sections of the second flow channel, e.g. the second connector 18A connects the second sections 14A and 14B₁ the second connector 18B connects the second sections 14B and 14C, etc.

The first flow channel and the second flow channel have a substantially quadratic cross section (about 40 mm X 40 mm) from the first port to the second port and from the third port to the fourth port, respectively.

The ports 4, 8, 12, 16 have fittings 4', 8', 12', 16' for connection to other heat exchanger modules or external units.

The heat exchanger module 2 has a first outer wall 20, a second outer wall 22, a third outer wall 24, a fourth outer wall 26, a first end wall 28, and a second end wall 30. Further, the heat exchanger module 2 comprises inner walls 32 forming a plurality of cavities forming sections of the flow channels in the heat exchanger module. Preferably, the inner walls of the heat exchanger separate two adjacent sections ^• thereby forming a common wall. The outer walls 20, 22, 24, 26 have a thickness of about 2 mm, and the inner walls 32 have a thickness of about 2 mm. The thickness of the walls may be selected according to desired operating pressure and optimum heat transfer. The first connectors and the second connectors connect first sections and second sections, respectively, via openings in the outer walls of the heat exchanger module.

A plurality of cleaning holes is formed in the first end wall 28, preferably one cleaning hole for each cavity forming a section of a flow channel. In an embodiment according to the present invention, a plurality of cleaning holes are formed in the second end wall 30 (not shown) preferably one cleaning hole for each cavity forming a section of a flow channel. The one or more cleaning holes have a threading for engagement with a corresponding plug member.

The heat exchanger module 2 further comprises a plurality of plug members 34 for sealing the cleaning holes in the end walls. The plug members 34 have a threading for engagement with the engagement member of a cleaning hole. The plug members may be unscrewed, thereby providing user access to the heat exchanger module.

Fig. 7 schematically illustrates a cross section of the heat exchanger module 2 according to the present invention. Inner walls 32 separate cavities or first sections 6A, 6B₁... , 6T forming a part of the first flow channel from cavities or second sections 14A, 14B,..., 14T forming a part of the second flow channel. Each section of the first and second flow channels except the first sections 6A, 6T and the second sections 14J, 14K abuts three different sections of the other flow channel. The heat exchanger module 2 has twenty first sections 6A, 6B, ..., 6T and twenty second sections 14A, 14B 14T. The first sections and the second sections are arranged in two columns including a first column comprising ten first sections 6A, 6B 6J and ten second sections 14K, 14L, .., 14T, and a second column comprising ten first sections 6K₁ 6L, ..., 6T and ten second sections 14A, 14B, .., 14J. The sections have a square cross section with a side length of 40 mm. Fig. 8 schematically illustrates a cross section of another embodiment of the heat exchanger module 102 corresponding to the embodiment of Fig. 1-7 except that the heat exchanger module 102 has fewer first and second sections and accordingly fewer first and second connectors. The heat exchanger module 102 has ten first sections 6A, 6B 6J and ten second sections 14A, 14B, ..., 14J. The first sections and the second sections are arranged in two columns including a first column comprising five first sections 6A, 6B 6E and five second sections 14F, 14G, .., 14J, and a second column comprising five first sections 6F, 6G, ..., 6J and five second sections 14A, 14B, .., 14E. The sections have a square cross section with a side length of about 40 mm. First connectors (not shown) connect the first sections and second connectors connect the second sections to form the first flow channel and the second flow channel, respectively.

Fig. 9 schematically illustrates a cross section of another embodiment of the heat exchanger module 202 corresponding to the embodiment of Fig. 1-7 except that the heat exchanger module 202 has fewer first and second sections and accordingly fewer first and second connectors. The exchanger module 202 has four first sections 6A, 6B, 6C, 6D and four second sections 14A, 14B, 14C₁ 14D. The first sections and the second sections are arranged in two columns including a first column comprising two first sections 6A, 6B and two second sections 14C, 14D, and a second column comprising two first sections 6C, 6D and two second sections 14A, 14B. The sections have a square cross section with a side length of about 50 mm. First connectors (not shown) connect the first sections and second connectors connect the second sections to form the first flow channel and the second flow channel, respectively.

Fig. 10 and Fig. 11 schematically illustrate a heat exchanger system according to the invention. The heat exchanger system 302 comprises a first heat exchanger module 2A and a second heat exchanger module 2B according to the invention. In the illustrated embodiment heat exchanger modules 2A and 2B correspond to the heat exchanger module schematically illustrated in Figs. 1-7. The heat exchanger system comprises a frame 304 carrying the heat exchanger modules 2A and 2B. Further, the heat exchanger system may comprise a plurality of insulation elements. The heat exchanger system 302 comprises six insulation elements 306, whereof two are not shown. The insulation elements 306 assist in insulating the heat exchanger system. The insulation elements 306 may be movably attached to the frame 304, e.g. by one or more hinges, for providing easy access to the heat exchanger modules.

The first port 4A of the first heat exchanger module 2A and the first port 4B of the second heat exchanger module 2B function as an inlet/outlet of a flow channel in the heat exchanger system 302. The second port 8A of the first heat exchanger module 2A and the second port 8B of the second heat exchanger module 2B are connected by a module connector 308 thereby forming a flow channel 316 from the first port 4A to the first port 4B. The fourth port 16A of the first heat exchanger module 2A and the fourth port 16B of the second heat exchanger module 2B function as an inlet/outlet of a flow channel in the heat exchanger system 302. The third port 12A of the first heat exchanger module 2A and the third port 12B of the second heat exchanger module 2B are connected by a module connector 312 thereby forming a flow channel 318 from the fourth port 16A to the fourth port 16B.

One or more ports functioning as inlet/outlet of a flow channel may be provided with fittings, e.g. a T-piece, to allow easy coupling, e.g. via valves, of the flow channel to different fluid loops, such as a fluid loop with liquid manure and a fluid loop with cleaning fluid. In the heat exchanger system illustrated in Fig. 10, each of the heat exchanger modules 2A and 2B are provided with a casing 314A and 314B, respectively, for reinforcement of the outer walls of the respective modules.

Further, Fig. 11 schematically illustrates a way of operating the heat exchanger system 302. First fluid having a temperature T_A enters the heat exchanger system at A through the first port 4A, passes through the heat exchanger system and leaves the system through the first port 4B at B having a temperature T₆. Second fluid having a temperature T_c enters the heat exchanger system at C through the fourth port 16B, passes through the heat exchanger system and leaves the system through the fourth port 16A at D having a temperature T_D. Thereby first fluid in a first section flows in the opposite direction of the flow of the second fluid in two adjacent second sections. Fig. 12 illustrates an embodiment 402 of a heat exchanger system according to an alternative embodiment of the present invention. In the heat exchanger system 402, the second port 8A of the first heat exchanger module and the second port 8B of the second heat exchanger module are connected by a module connector or fittings 404 preferably having a cross section corresponding to the sections of the heat exchanger modules, thereby forming a main flow channel 406 from the first port 4A of the first heat exchanger module 2A to the first port 4B of the second heat exchanger module 2B as schematically illustrated in Fig. 12. The third port 12A and the fourth port 16A of the first heat exchanger module form inlets/outlets for a first secondary flow channel 408, and the third port 12B and the fourth port 16B of the second heat exchanger module form inlets/outlets for a second secondary flow channel 410. In this embodiment, a first fluid in the main flow channel exchanges heat with a second fluid in the first secondary flow channel in the first heat exchanger module and exchanges heat with a third fluid in the second secondary flow channel in the second heat exchanger module. First fluid having a temperature T_A enters the heat exchanger system 402 at A through the first port 4A, passes through the heat exchanger system and leaves the system through the first port 4B at B having a temperature T_B. Second fluid having a temperature Tc enters the heat exchanger system at C through the third port 12A, passes through the heat exchanger system and leaves the system through the fourth port 16A at D having a temperature T₀. Third fluid having.a temperature T_F enters the heat exchanger system at F through the fourth port 16B, passes through the heat exchanger system and leaves the system through the third port 12B at E having a temperature T_E.

The number of heat exchanger modules may be decided according to desired amount of heat to be transferred, and the modules may be connected depending on e.g. number and temperature of fluids to be heat exchanged, operating pressure, etc.

Claims

1. A heat exchanger module having walls and comprising a first flow channel positioned in thermal contact with a second flow channel for heat exchange between a first fluid flowing in the first flow channel and a second fluid flowing in the second flow channel, c h a r a c t e r i z e d in that a first section of the first flow channel abuts at least three second sections of the second flow channel.

2. A heat exchanger module according to claim 1 , wherein first sections of the first flow channel and second sections of the second flow channel are tubular.

3. A heat exchanger module according to any of the claims 1 -2, wherein first sections of the first flow channel and second sections of the second flow channel have four walls.

4. A heat exchanger module according to any of the preceding claims, wherein the heat exchanger module comprises first connectors connecting first sections of the first flow channel.

5. A heat exchanger module according to any of the preceding claims, wherein the heat exchanger module comprises second connectors connecting second sections of the second flow channel.

6. A heat exchanger module according to any of the preceding claims, comprising one or more cleaning holes.

7. A heat exchanger module according to claim 6, further comprising one or more plug members for sealing the one or more cleaning holes.

8. A heat exchanger module according to any of the preceding claims, wherein the first sections and the second sections have a rectangular cross section.

9. A heat exchanger module according to any of the preceding claims, wherein the heat exchanger module comprises a first port and a second port, each port forming an inlet/outlet for the first flow channel.

10. A heat exchanger module according to any of the preceding claims, wherein the heat exchanger module comprises a third port and a fourth port, each port forming an inlet/outlet for the second flow channel.

11. A heat exchanger module according to any of the preceding claims, wherein the heat exchanger module is made of stainless steel.

12. A heat exchanger module according to any of the preceding claims, wherein the heat exchanger module is made of acid-resisting steel.

13. A heat exchanger module according to any of the preceding claims, wherein the first flow channel includes at least three first sections and the second flow channel includes at least three second sections alternately arranged in a first column comprising two first sections and a second section arranged between the first sections, and a second column comprising one first section arranged between two second sections, such that the second section in the first column abuts the two first sections in the first column and the first section in the second column.

14. A heat exchanger system comprising one or more heat exchanger modules according to any of the preceding claims.

15. A heat exchanger system according to claim 14, wherein the heat exchanger system comprises a first heat exchanger module and a second heat module that are interconnected by one or more module connectors, such as fittings.