WO2019149446A1

WO2019149446A1 - Insulating surface coating on heat exchangers for reducing thermal stresses

Info

Publication number: WO2019149446A1
Application number: PCT/EP2019/025016
Authority: WO
Inventors: Reinhold Hölzl; Axel Lehmacher; Alexander WOITALKA
Original assignee: Linde Aktiengesellschaft
Priority date: 2018-01-30
Filing date: 2019-01-17
Publication date: 2019-08-08
Also published as: CN111684230A; JP2021512267A; ES2930008T3; US20200400392A1; CN111684230B; EP3746728B1; EP3746728A1

Abstract

The invention relates to a plate heat exchanger (10) having a plate heat exchanger block (11), which has a plurality of partitions (4, 5) arranged parallel to one another in the form of separating plates which form a plurality of heat exchange passages (1a, 1b) for fluids which are to be brought into indirect heat exchange relationship with one another. The heat exchange passages are closed off from the outside by lateral strips (8), and each heat exchange passage (1a, 1b) has an inlet (9) for inflow of a fluid and an outlet (19) for outflow of the fluid. According to the invention, one or more partitions (4, 5) and/or one or more heat-conducting elements (2, 3) in each case have a coating (41) made of a heat-insulating material. The invention further relates to a method for producing a polymer laminate and to a method for joining prefabricated polymer components to each other.

Description

description

Insulating surface coating on heat exchangers to reduce thermal stress

The invention relates to a plate heat exchanger and a method for

Production of such a plate heat exchanger.

Plate heat exchangers are known from the prior art, which are adapted to transfer the heat from a first fluid indirectly to another, second fluid. The fluids in the plate heat exchanger are guided in separate heat exchange passages of the plate heat exchanger block. These are delimited by two parallel partitions of the plate heat exchanger block, between each of which a heating surface element is arranged, which is also referred to as a fin or lamella.

Such plate heat exchangers are e.g. shown and described in "The Standards of the brazed aluminum plate-fin heat exchanger manufacturers association" ALPEMA, Third Edition, 2010.

Furthermore, such aluminum plate heat exchangers are used in particular in cryogenic processes, e.g. in air separation plants. The said

Partitions or sheets and fins on the one hand form the heating surface and on the other hand have to absorb the forces from the internal overpressure. In this regard, various partitions and Fintypen are available, but the

Design options are limited by the pressure-bearing function. Any reduction of the specific heating surface is therefore not possible. It is also usually not desirable, since normally a high heating surface density and thus the most compact design is desired.

Starting, in particular restarting, heat exchangers, in particular aluminum plate heat exchangers, after a short or medium term

System downtime can lead to very high thermal stresses. This is especially true when the overall temperature change in the apparatus is large, such as which is the case for example with main heat exchangers of air separation plants. As a result, such heat exchangers are at risk of being damaged by a relatively small number of re-starts due to material fatigue.

In this regard, however, systems are desired that are flexible operable, which includes in particular the above-mentioned business interruptions.

The high thermal stresses are caused as follows: In a plant standstill, all process streams usually come to a standstill. Based on a temperature profile with a hot and a cold end, the material temperature differences are similar by heat conduction within the

Heat exchanger slowly and the apparatus assumes a homogeneous (average) temperature, which is between the maximum and minimum temperature of the

Initial state is. The insulation losses are usually small, so that this condition changes only slowly.

If the process streams are now started again, they hit the heat exchanger with a very large temperature difference. This has the consequence that the wall temperature, in particular in the area of the current inlets, changes rapidly over time, and that locally very steep wall temperature gradients develop along the main flow direction. The temporal and local temperature gradients cause the mentioned thermal stresses. In particular, in large, manufactured in modular heat exchangers, which have a plurality of interconnected plate heat exchanger blocks, the thermal stresses can be significant.

On this basis, the present invention seeks to provide a plate heat exchanger, which is improved in view of the aforementioned problem.

This object is achieved by a plate heat exchanger with the features of claim 1.

Thereafter, a plate heat exchanger with a plate heat exchanger block provided, which has a plurality of mutually parallel partitions (eg in the form of dividing plates), which form a plurality of heat exchange passages for each other to be brought in indirect heat transfer fluids, wherein the heat exchange passages provided by, in particular flush on the edge of the partitions, sidebars (eg in shape sheet metal strip), which are also referred to as sidebars, are limited, in particular outwardly closed, and between, in particular two, adjacent partitions at least one heat-conducting element (which is also referred to as fin) is arranged, and wherein the heat exchange passages , in particular each heat exchange passage, an inlet for introducing a fluid and an outlet for discharging the fluid.

According to the invention, it is provided that one or more partitions and / or one or more heat-conducting elements and / or one or more side strips each have a coating of a heat-insulating material, which is applied to the respective partition, the respective heat-conducting element or the respective sidebar.

The two outermost partitions of the plate heat exchanger block, which limit the plate heat exchanger block to the outside, are also called

Cover walls designated and are formed in particular by cover plates.

The respective heat exchange passage is therefore bounded by two adjacent partitions and has at least one heat-conducting element (Fin) arranged between these partitions.

According to one embodiment, the respective thermally conductive element forms with the two adjacent partitions a plurality of flow channels of the respective heat exchange passage, wherein the coating is applied to the respective thermally conductive element and the two adjacent partition plates, that the respective flow channel has a circumferential inner side, the coated with the heat-insulating coating. Preferably, the coating is applied in such a way that the respective flow channel in a first section has a gap-free coating, ie continuous coating, on its inner wall. According to a further embodiment it is provided that the respective

thermally conductive element alternately and preferably parallel to each other

arranged mountains (or head sections) and valleys (or foot sections), wherein the mountains and valleys are connected to each other in particular vertically extending webs. The alternately arranged mountains and valleys together with the webs form a corrugated structure of the respective heat-conducting element.

When the mountains are connected to one partition wall of the two adjacent partition walls and the valleys are connected to the other partition wall of the two adjacent partition walls, a plurality of flow channels are formed in a respective heat exchange passage. The respective flow channels are thus limited by the partitions, the mountains or the valleys and the webs of the respective thermally conductive element.

Such plate heat exchangers or the uncoated components of the plate heat exchanger are preferably formed from an aluminum alloy, wherein the components are preferably interconnected by brazing. In the manufacture of a plate heat exchanger, heating surface elements,

Dividers, cover plates and sidebars, which are partially provided with solder, preferably stacked in a block-shaped block and then soldered in a vacuum soldering oven to a heat exchanger block. Other

However, manufacturing methods are also conceivable.

The heat-conducting elements, which are optionally coated as described above, may in particular also be so-called distributor fins which distribute the fluid flow over the entire width of the respective heat exchange passage, i.e. from sidebar to sidebar. Such distributor fins may also be integrally formed with a downstream heat conducting element / fin.

According to one embodiment of the invention, provision is made for the respective partition wall having the coating and / or the respective heat-conducting element having the coating to each have a first section arranged at the respective inlet (which adjoins, for example, the inlet or adjacent to the inlet and a second portion connected to the first portion, which is farther from the inlet, than the first portion, wherein only the first portion has the coating, and wherein in each case the second portion does not have the coating, ie in other So words no heat-insulating coating has. In other words, in other words, the first section is arranged such that it is flowed through by the fluid before the fluid flows through the second section.

Accordingly, the flow channels formed by the partitions and heat-conducting elements thus have a first (closer to the inlet) and a second section (located closer to the outlet) portion, wherein each only an inner side or inner wall of the first portion of the respective

Flow channel having the heat-insulating coating.

Furthermore, it is provided according to an embodiment of the invention that the plate heat exchanger block at least first heat exchange passages to

Receiving a first fluid and second heat exchange passages for receiving a second fluid, wherein the first heat exchange passages associated surfaces of the partition walls and / or sidebars and / or the first heat exchange passages associated heat-conducting elements at least partially each have a coating of the heat-insulating material, namely in particular, only the first sections of these partitions and / or heat-conducting elements, and / or side rails and wherein the second heat exchange passages associated surfaces of the partition walls and / or the side rails and / or the second heat exchange passages associated heat-conducting elements have no coating of the heat-insulating material.

Thus, in particular, only the flow channels of the first point here

Heat exchange passages on a heat-insulating coating, and in particular only the inner sides or inner surfaces of the first portions of the

Flow channels, whereas the flow channels of the second

Heat exchange passages in particular do not have the heat-insulating coating. Furthermore, according to one embodiment of the invention, it is provided that the heat-insulating material is one of the following materials or has one of the following materials: a plastic, a polymer, a ceramic.

According to a further embodiment of the invention it is provided that the partitions and / or the heat-conducting elements and / or the side strips (apart from the coating) are formed from one of the following materials or have one of the following materials: aluminum, an aluminum alloy. As alloys, e.g. SB-209 (ASME), SB-221 (ASME) or EN-AW-3003 (EN).

Furthermore, according to an embodiment of the invention, it is provided that the heat-insulating material has a thermal conductivity or a heat conduction coefficient which is less than 5 W / mK, in particular less than 1 W / mK.

In contrast, the base material of the respective door wall or of the respective heat-conducting element or the respective uncoated partition wall or the respective uncoated heat-conducting element according to an embodiment of the invention typically has a heat conduction coefficient (eg 70K) in the range of approximately 130 W / mk (at 70K ) up to approx. 150 W / mk (at 300K).

Furthermore, according to an embodiment of the invention, it is provided that the respective coating has a thickness (in particular normal to the plane of extent or surface of the respective partition wall or of the respective heat-conducting element) which is less than or equal to 0.2 mm.

Furthermore, according to an embodiment of the invention, provision is made for the respective, uncoated dividing wall (in particular, normal to the plane of extent of the surface of the respective dividing wall) to have a thickness in the range from 1 mm to 2 mm.

According to one embodiment of the invention, it is further provided that the respective, uncoated thermally conductive element (in particular normal to

Plane of extension of the surface of the respective base body) has a thickness in

Range of 0.2 mm to 0.6 mm. For introducing fluids, the at least one, first one is above the inlet

Heat exchange passage and over the inlet of the at least one, second heat exchange passage according to an embodiment of the invention depending mounted a collector with a nozzle, wherein the nozzles are used for connecting feed pipes.

Such collectors may e.g. be formed as a half-cylinder, which are closed at the two opposite end faces. Such a collector further preferably has a peripheral edge over which the collector is welded to the plate heat exchanger block. The partitions and fins preferably run perpendicular to a longitudinal axis of the collector, if this

intended to be welded to the plate heat exchanger block. In this way, inlets or outlets of the respective heat exchange passage, which are each bounded by two adjacent partitions, open into the respective collector. Furthermore, the nozzle associated with the collector is preferably cylindrical and is connected via an end face of the nozzle with the

Collector welded so that the nozzle with a through hole of the

Collector and the collector is in flow communication.

The plate heat exchanger, according to one embodiment per fluid, which is guided in the plate heat exchanger, at least two collectors with nozzle, wherein the fluid via the one, first, nozzle and collector in the associated

Heat exchange passages can be introduced and on the other, second, collector or nozzle is again routable.

With regard to the collector / nozzle, according to one embodiment of the invention, it may be provided that the collector and / or the nozzle of the first heat exchange passages has a coating of the heat-insulating material on their respective inner sides (or inner walls or inner surfaces).

In contrast, the collectors and / or nozzles of the said second

Heat exchange passages according to an embodiment of the invention no

Coating of the heat-insulating material. Furthermore, according to an embodiment of the invention, it is provided that the respective heat-conducting element has a wave-shaped structure with alternating foot sections and head sections, wherein the respective foot section is connected via a web to an adjacent head section, so that said wave-shaped structure results. The wave-shaped structure can be rounded in the transition from the foot sections or head sections to the respective webs. However, it may also have a rectangular or stepped shape. The wave-shaped structure-together with the two-sided partitions-forms flow channels for guiding the relevant fluid in the respective heat exchange passage.

According to one embodiment of the invention, it is provided that the respective heat-conducting element is not coated with the heat-insulating coating at the contact surfaces, via which the respective heat-conducting element is connected (in particular soldered) to an adjacent dividing wall.

In accordance with a further embodiment, it is provided that the webs of the respective heat-conducting element (in particular in the first section of the respective heat-conducting element) have the heat-insulating coating or are coated with the heat-insulating coating.

Furthermore, according to an embodiment of the invention, it is provided that the respective heat-conducting element has the heat-insulating coating only in the region of the webs or is coated with the heat-insulating coating.

According to a further embodiment it is provided that the respective

heat-conducting element (in particular in the first section) only in the region of the surface facing the respective flow channel has the heat-insulating coating or is coated with the heat-insulating coating.

Due to the preferably corrugated structure of the heat-conducting elements, a coating of the webs already proves to be very effective due to the comparatively large total surface area of the webs (in comparison to the surface of the respective partition wall). Another aspect of the present invention relates to a process for producing a plate heat exchanger according to the invention, wherein a flowable material which forms a heat-insulating material in the cured state, in

Heat exchange passages of Plattenwärmeübertragerblocks is initiated, the partitions and / or heat-conducting elements and / or sidebars to receive the said coating, wherein the material is cured to form the said coatings. The flowable material is introduced in particular in the said flow channels of the heat exchange passages, which are formed by the respective heat-conducting element, the two adjacent partitions and possibly the side strips.

According to one embodiment of the method according to the invention, it is provided that the plate heat exchanger block is dipped into the flowable material at least in sections, in particular with a first section, in order to introduce the flowable material into the corresponding heat exchange passages or flow channels. With such a dipping method, the size of the area to be coated can advantageously be precisely controlled.

In this regard, according to one embodiment of the method, it is provided that heat exchange passages or flow channels, which are not to be coated, are previously correspondingly sealed, so that the material can not penetrate there.

A further aspect of the present invention relates to a method for operating a plate heat exchanger according to the invention, wherein at least a first and a second fluid in at least one heat exchange passage of the

Plattenwärmeübertragers are introduced so that the said fluids can exchange heat indirectly.

In the context of the present invention, said (at least two) fluids or fluid streams may be materially identical or differ in their material composition.

Furthermore, according to an embodiment of the method according to the invention - as well as in the plate heat exchanger according to the invention - all Heat exchange passages (or their flow channels) have a coating of the heat-insulating material (in particular a coating of the

Partitions and / or heat-conducting elements, and / or the side rails of the respective heat exchange passage).

According to a further embodiment of the method according to the invention /

Plattenwärmeübertragers can only those heat exchange passages or flow channels, which are assigned to a certain fluid (eg the first fluid), a coating of the heat-insulating material (in particular a coating of the partitions and / or heat-conducting elements and / or the side rails of the respective heat exchange passage) while others

Heat exchange passages (in particular their partitions and / or

heat-conducting elements) or flow channels have no coating of the heat-insulating material. The individual coatings may be formed or arranged in one of the manners already described above.

Furthermore, it is provided according to an embodiment of the method according to the invention, that the first fluid in the at least one first

Heat exchange passage and the second fluid in the at least one second

Heat exchange passage is initiated.

In this case, according to an embodiment of the method according to the invention, it is further provided that when starting the plate heat exchanger, the first fluid is introduced into the at least one first heat exchange passage before the second fluid is introduced into the at least one second heat exchange passage.

The starting means in particular a process in which, e.g. after stopping all the fluids previously through the plate heat exchanger or through

Heat exchange passages of the plate heat exchanger have been passed or after a first time providing the heat exchanger not previously used for heat transfer, the fluids involved in the heat exchange are reintroduced into the plate heat exchanger, in which case the first fluid is introduced before the second fluid in the plate heat exchanger. In particular, the first fluid is first introduced into the plate heat exchanger (ie before all other fluids or at least simultaneously with possibly further fluids). Alternatively, this is the first one Fluid at least under those fluids that before the second fluid in the

Plate heat exchangers are initiated.

Furthermore, according to one embodiment of the method according to the invention, provision is made for the first fluid to be introduced into the at least one first heat exchange passage via the neck and collector, which is arranged above the inlet of the at least one first heat exchange passage.

Furthermore, for example, the at least one first fluid, which is introduced when starting especially before all other fluids, in the plate heat exchanger have an inlet temperature in the range of 3K to 360K, wherein the

Plate heat exchanger before starting a temperature, in particular a homogeneous temperature, in this range from 3K to 360K may have.

Furthermore, the first fluid at startup may have a temperature which is about a differential temperature, the z. B. in the range of 10 K to 100 K, in particular 20K to 50K, is different from a temperature of the plate heat exchanger before starting.

The technical teaching according to the invention advantageously allows temporal and spatial temperature gradients to be reduced by an optionally partial reduction of the heat transfer. This reduces the thermal stresses, in particular during the above-mentioned starting operations, in particular restarting operations. The apparatus can withstand a higher number of such operations, thereby prolonging the life.

Further features and advantages of the present invention are intended in the

following description of the figures of embodiments of the invention will be described with reference to the figures. Show it:

Fig. 1 is a perspective view of an inventive

Plate Heat Exchanger

FIG. 2 shows a detail from a cross section through the plate heat exchanger of FIG. 1 along the sectional plane SS shown in FIG Fig. 1 shows a plate heat exchanger 10 according to the invention, which has a plurality of mutually parallel partitions in the form of partitions 4, comprising a plurality of heat exchange passages, eg 1 a, 1 b, for the transferable to each other in indirect heat transfer fluids A, B, C. , D, E form. The

Heat exchange between the heat exchange participating fluids takes place between adjacent heat exchange passages 1 a, 1 b, wherein the heat exchange passages 1 a, 1 b and thus the fluids are separated by the separating plates 4 from each other.

The heat exchange takes place by means of heat transfer via the separating plates 4 and via the heat-conducting elements 2, 3 arranged between the separating plates 4, which are also referred to as fins 2, 3. The fins 2 shown in Figure 1 also serve the uniform distribution of the fluids over the respective

Heat exchange passage 1 a, 1 b.

The heat exchange passages 1 a, 1 b are defined by in particular flush on the edge of the dividers 4 arranged side strips 8 in the form of metal strips 8, hereinafter also referred to as sidebars 8, limited. In particular, the

Heat exchange passages 1 a, 1 b through the sidebars 8 to the outside, ie the environment of the heat exchanger 10, completed.

Within the heat exchange passages 1 a, 1 b, ie between each two partition walls 4, the preferably corrugated fins 2, 3 are arranged, wherein a cross-section of a fin 3 is shown in a detail in FIG.

Thereafter, the fins 3 each have a wave-shaped structure with alternating foot portions 12, hereinafter also referred to as valleys 12, and head portions 14, hereinafter also referred to as mountains 14, the valleys 12 and mountains 14 are arranged parallel to each other on. A valley 12 is connected to an adjacent mountain 14 via a particular vertically extending web 13 of the respective fin 3, so that the said wave-shaped structure results. The wave-shaped structure can be rounded in the transition from valleys 12 or mountains 14 to the respective webs 13. However, it can also be a rectangular or

have stepped shape. Due to the undulating structure - formed together with the two-sided partitions 4 - flow channels 40 for guiding the respective fluid in the respective heat exchange passage 1 a, 1 b.

The mountains 14 and valleys 12 of the respective fins 3 are materially connected to the respective adjacent dividing plates 4, preferably by solder joints. The participating in the heat exchange fluids are thus in direct thermal contact with the wavy structures 3, so that the heat transfer through the thermal contact between the mountains 14 and valleys 12 and T rennblechen 4, and thus by heat conduction is ensured. In order to optimize the heat transfer, the orientation of the wave-shaped structure 3 within the heat exchange passages 1 a, 1 b is selected depending on the application so that a DC, cross, counter or cross counterflow between adjacent passages 1 a, 1 b is made possible ,

The plate heat exchanger 10 also has inlets 9 to the

Heat exchange passages 1 a, 1 b (wherein in FIG 1 only one inlet 9 to a second heat exchange passage 1 b is shown for clarity), which are exemplarily provided at the ends of the plate heat exchanger 10 (inlets at a central portion are also possible ), via the inlets 9, the fluids A, B, C, D, E in the heat exchange passages 1 a, 1 b introduced or can be deducted from these. In the region of these inlets 9, the individual heat exchange passages 1 a, 1 b may have fins in the form of distributor fins 2 which distribute the respective fluid to the channels of a fins 3 of the relevant heat exchange passage 1 a, 1 b. Distribution fins 2 are not mandatory. A fluid A, B,

C, D, E can thus be introduced via an inlet 9 of the plate heat exchanger block 1 1 in the associated heat exchange passage 1 a, 1 b and through a further opening 19, an outlet 19, from the relevant

Heat exchange passage 1 a, 1 b are deducted again.

The dividing plates 4, fins 3 and sidebars 8 and optionally further components (for example the distributor fins 2 shown) are used e.g. connected by brazing. For this purpose, the partially soldered components such as Heizflächenelemente (fins) 3, dividers 4, distribution fins 2, cover plates 5 and 8 sidebars are stacked on each other in a block and then in an oven to a

Heat exchanger block 1 1 brazed. For supplying or removing the heat-exchanging fluids A, B, C, D, E, semi-cylindrical collectors 7 (or headers) are preferably welded over the inlets 9 and outlets 19. Furthermore, a cylindrical neck 6 is preferably welded to each collector 7. The connecting pieces 6 are used to connect an incoming or outgoing pipeline to the respective collector 7.

As already explained above, in the case of plate heat exchangers of the type shown in FIG. 1, there is basically the problem that, when starting up or restarting, the currents which are introduced into the plate heat exchanger have a distinct temperature difference with respect to the standstill temperature of the block 11. The resulting strains and the stresses induced thereby can damage the plate heat exchanger. A standstill temperature of the block 1 1 results when the temperatures of the hot and the cold end of the block 1 1 approach due to the stoppage of the process streams or fluids to each other by heat transfer and thereby results in a homogeneous temperature of the fluids and components in the plate heat exchanger.

According to the invention, it is therefore provided that one or more partition walls 4, 5 and / or one or more heat-conducting elements 2, 3 and / or one or more side strips 8 each have a coating 41 of a heat-insulating material, which on the respective partition wall 4, fifth or the respective heat-conducting element 2, 3 is applied.

Examples of suitable thermally insulating materials are disclosed herein. The base material is in particular an aluminum alloy (for example of the type 3003). Other suitable aluminum alloys / materials are also conceivable.

The heat-insulating coating 41 is preferably applied to the partitions 4 and thermally conductive elements (fins) 2, 3 and possibly the sidebars 8 such that the flow channels 40 with the heat-insulating coating 41st

preferably in at least a first section A1 of the heat exchange passages 1 a are completely coated (see detail of Figure 1). In particular, according to one embodiment, it may be provided that only a certain area or a first section A1 of the partitions 4, 5 and the heat-conducting elements 2, 3 and / or side strips 8 or the flow channels 40 and the heat exchange passages 1 a, 1 b a has heat-insulating coating 41. This first section A1 can further, z. B. along the

Transition plane U, which is indicated in the figure 1 by a dashed line, in a second section A2 of the partitions 4, 5 or heat-conducting elements 2, 3 or sidebars 8 merge, the z. B. not with an inventive

Coating 41 is provided. In this second section A2 so can the

Inner sides of the flow channels 40 have no heat-insulating coating.

In this case, the first section A1 preferably adjoins inlets 9 for the first

Heat exchange passages 1 a, via which a first fluid B at a start, in particular restarting, before other fluids (eg, before a second fluid A) is introduced into the block 1 1. Furthermore, such a coating 41 may also be provided on the collector 7 and / or port 6, via which the first fluid B is introduced into the inlets 9.

LIST OF REFERENCE NUMBERS

Claims

claims

A plate heat exchanger (10) having a plate heat exchanger block (1 1) having a plurality of mutually parallel partitions (4, 5) forming a plurality of heat exchange passages (1 a, 1 b) for each other to be brought in indirect heat transfer fluids, said the

Heat exchange passages (1 a, 1 b) are limited by side strips (8), and wherein between adjacent partitions (4, 5), a heat-conducting member (2, 3) is arranged, and wherein the heat exchange passages (1 a, 1 b) each one Inlet (9) for introducing a fluid and an outlet (19) for discharging the fluid, characterized in that a plurality of partitions (4, 5) and / or a plurality of heat-conducting elements (2, 3) each have a coating (41) of a have heat-insulating material.

2. Plate heat exchanger according to claim 1, characterized in that the coating (41) having partition (4, 5) and / or that the coating (41) having thermally conductive element (2, 3) at the inlet (9) arranged first Section (A1) and a second section (A2) connected to the first section (A1), the second section (A2) being farther from the inlet (9) than the first section (A1), and the first section (A1) A1) has the coating (41), and wherein the second portion (A2) has no heat-insulating coating.

3. Plate heat exchanger according to one of the preceding claim, characterized in that the plate heat exchanger block (1 1) at least first heat exchange passages (1 a) for receiving a first fluid (B) and second heat exchange passages (1 b) for receiving a second fluid (A) , wherein the first heat exchange passages (1 a) each one

Coating (41) of the heat-insulating material, and wherein the second heat exchange passages (1 b) have no coating of the heat-insulating material.

4. Plate heat exchanger according to one of the preceding claims, characterized in that the heat-insulating material is one of the following materials or one of the following materials: a plastic, a polymer, a ceramic.

5. Plate heat exchanger according to one of the preceding claims, characterized in that the heat-insulating material has a

Wärmeleitkoeffizienten which is less than 5 W / mK, in particular less than 1 W / mK.

6. Plate heat exchanger according to one of the preceding claims, characterized in that the respective coating (41) has a thickness (D1) which is less than or equal to 0.2 mm.

7. Plate heat exchanger according to one of the preceding claims, characterized in that for introducing fluids (B) via the inlets (9) of the first heat exchange passages (1 a) and via the inlets (9) of the second heat exchange passages (1 b) each a collector (7) with a connecting piece (6) is mounted.

8. Plate heat exchanger according to claim 7, characterized in that the collector (7) and / or the nozzle (6) of the first heat exchange passages (1 a) has a coating (41) made of the heat-insulating material.

9. Plate heat exchanger according to one of the preceding claims, characterized in that the respective heat-conducting element (2, 3) has a wavy structure with alternating foot sections (12) and

Head portions (14), wherein the respective foot portion (12) via a web (13) with an adjacent head portion (14) is connected.

10. A method for producing a plate heat exchanger according to one of

preceding claims, wherein a flowable material which forms a heat-insulating material in the cured state, in heat exchange passages (1 a) of the plate heat exchanger block (1 1) is introduced, the partitions and / or heat-conducting elements (2, 3) and / or side strips (8)

To obtain coating (41), wherein the material is cured to form the coatings (41).

1 1. A method according to claim 10, characterized in that the

Plate heat exchanger block (1 1) is at least partially immersed in the flowable material to the flowable material in the corresponding

Heat exchange passages (1) to initiate.

12. A method of operating a plate heat exchanger according to one of

preceding claims, wherein at least a first fluid (B) and a second fluid (A) in at least one heat exchange passage (1 a, 1 b) of the

Plattenwärmeübertragers are introduced so that the fluids (B, A) can exchange heat.

13. The method of claim 12, wherein the first fluid (B) in the at least one first heat exchange passage (1 a) and the second fluid (A) in the at least one second heat exchange passage (1 b) is initiated.

14. The method according to claim 12 or 13, wherein when starting the

Plattenwärmeübertragers the first fluid (B) in the at least one first

Heat exchange passage (1 a) is initiated before the second fluid (A) is introduced into the at least one second heat exchange passage (1 b).

15. The method according to any one of claims 12 to 14, wherein the first fluid (B) via the nozzle (7) and collector (6) which is arranged above the inlet (9) of the at least one first heat exchange passage (1 a), in the at least one first heat exchange passage (1 a) is initiated.

16. The method according to any one of the preceding claims, wherein the at least one first fluid (B), which is introduced before the start of the plate heat exchanger before all other fluids in the plate heat exchanger, having a temperature which is a temperature difference of a temperature of the

Plate heat exchanger before starting differs.