EP3653983A1 - Plate heat exchanger, method for operating a plate heat exchanger and method for production of a plate heat exchanger - Google Patents

Abstract

A plate heat exchanger (1) for a process plant (26), with a connection device (9-18), in particular an inlet header, for supplying a liquid phase (FP) of a fluid (A-E) to be evaporated to the plate heat exchanger (1), a Heat exchanger block (2) which has a distributor opening (36) for distributing the liquid phase (FP) to a heat transfer passage (32) of the heat exchanger block (2), and a pressure loss element (52) which is arranged on the distributor opening (36) and which with the heat exchanger block (2) is connected in order to generate a pressure loss when the liquid phase (FP) flows into the heat exchanger block (2).

Description

The invention relates to a plate heat exchanger for a process plant, a method for operating such a plate heat exchanger and a method for producing such a plate heat exchanger.

With the help of a so-called plate heat exchanger or plate heat exchanger, heat exchange between several different fluids or media can be realized. For example, such a plate heat exchanger can be used for the production of liquefied natural gas (LNG). Here, natural gas is liquefied using a refrigerant, whereby the refrigerant evaporates. So-called mixed refrigerants can be used in particular as refrigerants. After expansion to operating pressure, these are two-phase and are separated into a gas phase and a liquid phase before the plate heat exchanger. The liquid phase is fed to the plate heat exchanger in a single phase via a so-called entry header. The liquid phase is evaporated upwards in the plate heat exchanger.

Evaporation of the liquid phase, which forms a two-phase flow after entering the plate heat exchanger, can lead to the phenomenon of so-called Ledinegg instability. Ledinegg instability can result in a total pressure loss of the liquid phase not increasing monotonically with a mass flow of the liquid phase over the length of a heat transfer passage of the plate heat exchanger. This results in a sink in the course of the total pressure loss over the mass flow. This sink means that the desired uniform distribution of the liquid phase on channels or passages of the heat transfer passage is no longer guaranteed, but there are channels or passages with a larger or a smaller mass flow with the same total pressure loss.

This unequal distribution can go so far that in some channels or passages the liquid phase is no longer completely evaporated and therefore biphasic from the Plate heat exchanger exits. The uneven distributions can therefore lead to a thermal underperformance of the plate heat exchanger. Furthermore, the uneven distributions can also lead to an uneven temperature profile in the plate heat exchanger and thus to thermal stresses. Therefore, it is desirable to prevent the occurrence of Ledinegg instability, or at least to reduce this phenomenon.

Against this background, an object of the present invention is to provide an improved plate heat exchanger.

Accordingly, a plate heat exchanger for a process plant is proposed. The plate heat exchanger comprises a connection device, in particular an inlet header, for supplying a liquid phase of a fluid to be evaporated to the plate heat exchanger, a heat exchanger block which has a distributor opening for distributing the liquid phase to a heat transmission passage of the heat exchanger block, and a pressure loss element which is arranged at the distributor opening and which is connected to the heat exchanger block in order to generate a pressure drop when the liquid phase flows into the heat exchanger block.

Because the pressure loss element is provided, an overall pressure loss can be generated which has a monotonic course with a relative mass flow of the liquid phase. The uniform distribution of the total flow of the liquid phase or parts thereof is ensured on the channels of the respective heat transfer passages of the heat exchanger block, the required heat conversion is achieved and the temperature distribution is homogenized.

The fluid is in particular a mixture refrigerant, which has the aforementioned liquid phase and a gas phase. Another fluid, for example natural gas, can be liquefied with the aid of the fluid. The process plant can be, for example, a plant for producing liquid gas or the like. The process plant can include a large number of such plate heat exchangers.

The plate heat exchanger or plate heat exchanger is in particular a so-called plate fin heat exchanger (PFHE) or can be referred to as such. The plate heat exchanger is preferably constructed from components that are made of aluminum and are brazed to one another. The plate heat exchanger can therefore also be referred to as a brazed aluminum plate heat exchanger. The heat exchanger block is in particular cuboid or block-shaped and preferably comprises a large number of heating surface elements and a large number of separating plates. The heating surface elements are so-called fins, in particular so-called heat transfer fins, or can be referred to as fins. The heating surface elements can be designed as corrugated or ribbed sheets, for example as aluminum sheets. Each heating surface element has a plurality of ribs or shafts arranged in parallel, between which passages or channels are formed. The channels of a heating surface element each form a heat transfer passage. The waves can be called ripples, webs or fin webs.

The heating surface elements and the separating plates are arranged alternately, so that a multiplicity of parallel heat transfer passages are formed in the heat exchanger block, in which the fluids can flow and can indirectly transfer heat to fluids guided in adjacent heat transfer passages. The individual heat transfer passages can be supplied with a respective fluid with the aid of respective connection devices or the respective fluid can be guided away from the plate heat exchanger with the aid of such a connection device. The connection devices are so-called headers, in particular entry headers or exit headers, or can be referred to as such.

In particular, exactly one or only one pressure loss element is provided. The pressure loss element can be any component which is suitable for generating a pressure loss at the distributor opening. The pressure loss element is in particular constructed analogously to the heating surface element. This means that the pressure loss element preferably comprises a plurality of ribs or shafts arranged in parallel, between which passages or channels arranged in parallel run. The waves can also be referred to as corrugations, webs or fin webs. The pressure loss element is a fin, in particular a so-called hardway fin, or can be referred to as such. In operation of the plate heat exchanger, the entire liquid phase which is supplied to a heat transfer passage is passed or forced through the pressure loss element. Leakage flows or bypass flows around the pressure element are preferably not provided.

The pressure loss element is preferably arranged outside the heat transmission passage, in particular outside an active region of the heat transmission passage. The active area of a heat transfer passage is in particular formed by the respective heating surface element. The pressure loss element is positioned upstream of the respective heating surface element. Distributor elements for evenly distributing the liquid phase over the channels of the heating surface element can be provided between the pressure loss element and the heating surface element.

The fact that the pressure loss element is arranged “at” the distributor opening can be understood to mean that the pressure loss element rests on an outer surface of the heat exchanger block or that the pressure loss element is received in the distributor opening. The fact that the pressure loss element is “connected” to the heat exchanger block means in particular that the pressure loss element is fastened directly to the plate heat exchanger and not to the connection device. For example, the pressure loss element can be integrally and / or positively connected to the heat exchanger block. In the case of integral connections, the connection partners are held together by atomic or molecular forces. Integral connections are non-detachable connections that can only be separated by destroying the connection means and / or the connection partner. A material connection can be made, for example, by soldering or welding. A positive connection is created by the interlocking or interlocking of at least two connection partners.

According to one embodiment, the pressure loss element is arranged within the distributor opening.

This means that an outer contour of the pressure loss element is received in an inner contour of the distributor opening. The outer contour and the inner contour can be rectangular. The pressure loss element is thus accommodated in the distributor opening. As mentioned previously, however, the pressure loss element can also rest on the outer surface of the heat exchanger block and cover the distributor opening. In this case, the pressure loss element is not positioned directly inside the distributor opening.

According to a further embodiment, the pressure loss element is arranged flush with an outer surface of the heat exchanger block.

In particular, the heating surface element and the distributor elements are framed by a plurality of frame-like wheel rims or sidebars. The outer surface is defined by the edge strips. "Flush" means that the pressure loss element does not protrude beyond the outer surface. Alternatively, the pressure loss element can also be set back with respect to the outer surface or project beyond it.

According to a further embodiment, the connection device is connected to the outer surface, the connection device covering the pressure loss element in such a way that the pressure loss element is arranged outside an interior of the connection device.

The interior is delimited in the direction of the heat exchanger block, in particular by the outer surface. In the event that the pressure loss element is arranged flush with or protrudes behind the outer surface, the pressure loss element is positioned outside the interior. In the event that the pressure loss element projects beyond the outer surface in the direction of the connection device or rests on the outer surface, the pressure loss element is arranged at least in sections within the interior.

According to a further embodiment, an outer contour of the pressure loss element is connected to the distributor opening in a fluid-tight manner.

This reliably prevents bypass flows. The outer contour comprises a plurality of side edges, in particular four side edges, all of which are connected in a fluid-tight manner to the distributor opening, in particular to the inner contour of the distributor opening are. The fluid-tight connection can be produced using a seal, for example using a sealing cord, using a soldered seam or using a welded seam.

According to a further embodiment, the pressure loss element is set up to generate a pressure loss of 20 mbar to 400 mbar.

The pressure loss can be generated, for example, with the aid of a perforation provided on the pressure loss element.

According to a further embodiment, the pressure loss element has a perforation through which the liquid phase flows completely during operation of the plate heat exchanger.

The perforation comprises a large number of openings which break through the pressure loss element. The breakthroughs can be holes or punched holes. The openings can be evenly or unevenly distributed over the pressure loss element. The pressure loss can be influenced and thus adjusted with the aid of a variation of a geometry and / or a cross-sectional area of the openings.

According to a further embodiment, the pressure loss element has shafts arranged parallel to one another and spaced apart from one another, between which channels are provided.

The waves can also be called ripples, ribs, webs or fin webs. A distance between the shafts can be changed in order to influence the pressure loss during the production of the pressure loss element. The distance can also be referred to as division or fin division.

According to a further embodiment, the pressure loss element is arranged perpendicular to a flow direction of the liquid phase through the pressure loss element.

Under "vertical" or "transverse" is in particular an angle of 90 ° ± 10 °, preferably 90 ° ± 5 °, more preferably 90 ° ± 3 °, more preferably 90 ° ± 1 °, more preferably exactly 90 ° to understand.

According to a further embodiment, the pressure loss element is integrally connected to the heat exchanger block with the aid of a connecting seam, and / or the pressure loss element is positively connected to the heat exchanger block with the aid of a tongue and groove system.

The connection seam is a solder seam or a weld seam. The weld seam preferably runs completely around the pressure loss element. A plurality of connecting seams can also be provided, which run completely around the pressure loss element. The tongue and groove system preferably comprises grooves provided on the heat exchanger block, into which spring sections of the pressure loss element engage in a form-fitting manner. The grooves are provided in particular on edge strips of the heat exchanger block.

• a) Einspeisen einer zu verdampfenden Flüssigphase eines Fluids in einen Wärmetauscherblock des Plattenwärmetauschers, b) Erzeugen eines Druckverlusts an einer Verteileröffnung des Wärmetauscherblocks mit Hilfe eines an der Verteileröffnung angeordneten und mit dem Wärmetauscherblock verbundenen Druckverlustelements, und c) Umwandeln der Flüssigphase in einen Zweiphasenstrom innerhalb des Wärmetauscherblocks während eines Wärmetauschs mit einem zu verflüssigenden Fluid.

Furthermore, a method for operating such a plate heat exchanger for a process plant is proposed. The process includes the steps:

• a) feeding a liquid phase of a fluid to be evaporated into a heat exchanger block of the plate heat exchanger, b) generating a pressure loss at a distributor opening of the heat exchanger block with the aid of a pressure loss element arranged at the distributor opening and connected to the heat exchanger block, and c) converting the liquid phase into a two-phase flow within the Heat exchanger blocks during a heat exchange with a fluid to be liquefied.

As previously mentioned, the fluid is a mixed refrigerant. The further fluid is preferably natural gas. Thus, the aforementioned method is also a method for producing liquefied natural gas.

According to one embodiment, a pressure loss of 20 mbar to 400 mbar is generated in step b).

The desired pressure loss can be set in particular by modifying the perforation of the pressure loss element and / or the division of the waves of the pressure loss element.

Furthermore, a method for producing such a plate heat exchanger for a process plant is proposed. The method comprises the steps: a) providing a heat exchanger block, b) providing a pressure loss element, c) arranging the pressure loss element at a distributor opening of the heat exchanger block, and d) connecting the pressure loss element to the heat exchanger block.

The provision of the heat exchanger block can include manufacturing, for example soldering individual parts, of the heat exchanger block. Providing the pressure loss element may include making the same. In step c), the pressure loss element can, for example, be placed on or placed in the distributor opening. For example, the pressure loss element can be soldered or welded to the heat exchanger block in step d). The pressure loss element can additionally or alternatively also be connected to the heat exchanger block in a form-fitting manner with the aid of the tongue and groove system.

According to one embodiment, a perforation is introduced into the pressure loss element before or in step b).

For example, when the pressure loss element is provided, the perforation can be introduced into the same in the form of bores or punchings. As previously mentioned, the perforation can be changed to achieve the desired pressure drop.

According to a further embodiment, a distance from adjacent shafts of the pressure loss element is set before or in step b).

This can also influence the pressure loss. The perforations of the perforation can be positioned one behind the other on the shafts, viewed in the direction of flow, or offset relative to one another transversely to the direction of flow.

In the present case, "a" is not necessarily to be understood as restricting to exactly one element. Rather, several elements, such as two, three or more, can also be provided. Nor is any other measure word used here to be understood to mean that there is a restriction to exactly the number of elements mentioned. Rather, numerical deviations upwards and downwards are possible, unless stated otherwise.

The embodiments and features described for the plate heat exchanger apply correspondingly to the proposed methods and vice versa.

Further possible implementations of the plate heat exchanger and / or of the methods also include combinations of features or embodiments described above or below with reference to the exemplary embodiments that are not explicitly mentioned. The person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the plate heat exchanger and / or the processes.

• Fig. 1 zeigt eine schematische perspektivische Ansicht einer Ausführungsform eines Plattenwärmetauschers;
• Fig. 2 zeigt eine schematische perspektivische Ansicht einer Ausführungsform eines Wärmetauscherblocks für den Plattenwärmetauscher gemäß Fig. 1;
• Fig. 3 zeigt eine stark vergrößerte schematische Teilschnittansicht des Plattenwärmetauschers gemäß Fig. 1;
• Fig. 4 zeigt eine weitere stark vergrößerte schematische Teilschnittansicht des Plattenwärmetauschers gemäß Fig. 1;
• Fig. 5 zeigt ein schematisches Diagramm des Druckverlaufs über dem relativen Massenstrom im Betrieb des Plattenwärmetauschers gemäß Fig. 1;
• Fig. 6 zeigt eine stark vergrößerte schematische Teilschnittansicht einer weiteren Ausführungsform eines Plattenwärmetauschers;
• Fig. 7 zeigt eine weitere stark vergrößerte schematische Teilschnittansicht des Plattenwärmetauschers gemäß Fig. 6;
• Fig. 8 zeigt eine schematische Ansicht einer Ausführungsform eines Druckverlustelements für den Plattenwärmetauscher gemäß Fig. 6;
• Fig. 9 zeigt eine weitere schematische Ansicht des Druckverlustelements gemäß Fig. 8;
• Fig. 10 zeigt ein schematisches Diagramm des Druckverlaufs über dem relativen Massenstrom im Betrieb des Plattenwärmetauschers gemäß Fig. 6;
• Fig. 11 zeigt eine stark vergrößerte schematische Teilschnittansicht einer weiteren Ausführungsform eines Plattenwärmetauschers;
• Fig. 12 zeigt ein schematisches Blockdiagramm einer Ausführungsform eines Verfahrens zum Betreiben des Plattenwärmetauschers gemäß Fig. 6 oder gemäß Fig. 11; und
• Fig. 13 zeigt ein schematisches Blockdiagramm einer Ausführungsform eines Verfahrens zum Herstellen des Plattenwärmetauschers gemäß Fig. 6 oder gemäß Fig. 11.

Further advantageous refinements and aspects of the plate heat exchanger and / or the method are the subject of the subclaims and the exemplary embodiments of the plate heat exchanger and / or the method described below. Furthermore, the plate heat exchanger and / or the method are explained in more detail on the basis of preferred embodiments with reference to the attached figures.

• Fig. 1 shows a schematic perspective view of an embodiment of a plate heat exchanger;
• Fig. 2 shows a schematic perspective view of an embodiment of a heat exchanger block for the plate heat exchanger according to Fig. 1 ;
• Fig. 3 shows a greatly enlarged schematic partial sectional view of the plate heat exchanger according to Fig. 1 ;
• Fig. 4 shows another greatly enlarged schematic partial sectional view of the plate heat exchanger according to Fig. 1 ;
• Fig. 5 shows a schematic diagram of the pressure curve over the relative mass flow in the operation of the plate heat exchanger according to Fig. 1 ;
• Fig. 6 shows a greatly enlarged schematic partial sectional view of a further embodiment of a plate heat exchanger;
• Fig. 7 shows another greatly enlarged schematic partial sectional view of the plate heat exchanger according to Fig. 6 ;
• Fig. 8 shows a schematic view of an embodiment of a pressure loss element for the plate heat exchanger according to Fig. 6 ;
• Fig. 9 shows a further schematic view of the pressure loss element according to Fig. 8 ;
• Fig. 10 shows a schematic diagram of the pressure curve over the relative mass flow in the operation of the plate heat exchanger according to Fig. 6 ;
• Fig. 11 shows a greatly enlarged schematic partial sectional view of a further embodiment of a plate heat exchanger;
• Fig. 12 shows a schematic block diagram of an embodiment of a method for operating the plate heat exchanger according to Fig. 6 or according to Fig. 11 ; and
• Fig. 13 10 shows a schematic block diagram of an embodiment of a method for manufacturing the plate heat exchanger according to FIG Fig. 6 or according to Fig. 11 .

In the figures, elements that are the same or have the same function have been provided with the same reference numerals, unless stated otherwise.

The Fig. 1 shows a schematic perspective view of an embodiment of a plate heat exchanger or plate heat exchanger 1. Die Fig. 2 shows a schematic perspective view of an embodiment of a heat exchanger block 2 for the plate heat exchanger 1 according to FIG Fig. 1 . Below is the Fig. 1 and 2nd referred to at the same time.

With the help of Fig. 1 plate heat exchanger 1 shown, a heat exchange between several different fluids A to E can be realized. The fluids A to E can also be referred to as process media or media. The plate heat exchanger 1 is in particular a plate fin heat exchanger (PFHE) or can be referred to as such. The plate heat exchanger 1 is preferably constructed from components which are made of aluminum and brazed to one another. The plate heat exchanger 1 can therefore also be referred to as a brazed aluminum plate heat exchanger.

The heat exchanger block 2 is cuboid or block-shaped and comprises a large number of heating surface elements 3 and a large number of separating plates 4. The heating surface elements 3 are so-called fins, in particular so-called heat transfer fins, or can be referred to as fins. The heating surface elements 3 can be designed as corrugated or ribbed sheets, for example as aluminum sheets. The partition plates 4 are partition plates or can be referred to as partition plates. The partition plates 4 can also be made of aluminum. The number of heating surface elements 3 and the number of partition plates 4 is arbitrary.

The heating surface elements 3 and the partition plates 4 are arranged alternately. That is, a partition plate 4 is positioned between two heating surface elements 3 and a heating surface element 3 is positioned between two partition plates 4. The heating surface elements 3 and the partition plates 4 can be integrally connected to one another. In the case of integral connections, the connection partners are held together by atomic or molecular forces. Integral connections are non-detachable connections that can only be separated from one another by destroying the connection means and / or the connection partner. In particular, the heating surface elements 3 and the separating plates 4 can be soldered to one another.

The heat exchanger block 2 further comprises cover plates 5, 6, between which the plurality of heating surface elements 3 and the plurality of partition plates 4 are arranged. The cover plates 5, 6 can be constructed identically to the partition plates 4. The cover plates 5, 6 are positioned on the outside on a respective outermost heating surface element 3 and close the heat exchanger block 2 in the orientation of FIG Fig. 1 and 2nd forward and backward. Furthermore, the heat exchanger block 2 comprises so-called side bars or edge strips 7, 8, which laterally limit the heating surface elements 3. The edge strips 7, 8 can be integrally connected, for example soldered, to the separating plates 4 and / or the heating surface elements 3.

With the help of the heating surface elements 3 and the separating plates 4, the plate heat exchanger 1 forms a multiplicity of parallel heat transfer passages in which the fluids A to E can flow and can indirectly transfer heat to fluids A to E guided in adjacent heat transfer passages. The individual heat transfer passages can be supplied with a respective fluid A to E with the aid of connection devices 9 to 18 or the respective fluid A to E can be guided away from the plate heat exchanger 1 with the aid of such a connection device 9 to 18. The connection devices 9 to 18 are so-called headers or can be referred to as such. The connection devices 9 to 18 can also be referred to as distributors.

For example, the connection devices 11, 13, 15 are suitable for supplying the fluids A, B, D to the plate heat exchanger 1, and the connection devices 9, 10, 12, 14 are suitable for supplying the fluids A, C, D, E from the plate heat exchanger 1 to dissipate. Each connection device 9 to 18 is assigned a connection piece 19 to 25, with which the respective connection device 9 to 18 can be acted upon by the corresponding fluid A to E or the corresponding fluid A to E can be guided away from the connection device 9 to 18. The connection devices 9 to 18 are integrally connected to the heat exchanger block 2. In particular, the connection devices 9 to 18 are welded to the heat exchanger block 2.

The plate heat exchanger 1 can be part of a process engineering system 26. Process engineering system 26 can, for example, be a system for Air separation, for the production of liquefied natural gas (LNG), a plant used in the petrochemical industry or the like. The process plant 26 can include a plurality of such plate heat exchangers 1.

The Fig. 3 and 4th each show a schematic partial sectional view of the plate heat exchanger 1. In the Fig. 3 is the connection device 15 different from the Fig. 1 not arranged laterally, but centrally on the heat exchanger block 2. A coordinate system of the plate heat exchanger 1 comprises an x direction or width direction x, a y direction or vertical direction y and a z direction or depth direction z.

Each heating surface element 3 has a large number in the Fig. 3 only schematically indicated ripples or waves 27 to 29, which in the orientation of the Fig. 3 are oriented from top to bottom or in a direction of gravity g. The waves 27 to 29 can also be referred to as ribs, webs or fin webs. The shafts 27 to 29 form a plurality of passages or channels 30, 31 running in the direction of gravity g. The entirety of the channels 30, 31 of the heating surface element 3 form at least part of a heat transfer passage 32 of the plate heat exchanger 1. In particular, the channels 30, 31 insert one flowable area of the heat transfer passage 32 fixed. Mechanically and for heat transfer, however, the shafts 27 to 29 and the separating plates 4 are also important. The channels 30, 31 can be in fluid communication with one another perpendicular to the direction of gravity g, that is to say in the width direction x. For this purpose, the shafts 27 to 29 can have perforations or perforations, for example, which enable a mass transfer between the channels 30, 31. The heating surface element 3 can be referred to as an active fin. The heating surface element 3 forms an active area of the heat transfer passage 32. Therefore, the heating surface element 3 can also be referred to as an active area.

As the Fig. 3 further shows, distributor elements 33 to 35 are also provided, which are suitable for evenly distributing a liquid phase FP of the fluid A from a distributor opening 36 of the heat exchanger block 2 to the channels 30, 31 of the heating surface element 3. The distributor elements 33 to 35 are preferably constructed analogously to the heating surface element 3. That is, the distributor element 33 comprises one Variety in the Fig. 3 only schematically indicated ripples or waves 37 to 39, which in the orientation of the Fig. 3 are oriented from top to bottom or in the direction of gravity g. The waves 37 to 39 can also be referred to as ribs, webs or fin webs. The shafts 37 to 39 form a plurality of passages or channels 40, 41 running in the direction of gravity g. The channels 40, 41 can be part of the heat transfer passage 32. The distributor element 33 is wedge-shaped and comprises two side edges 42, 43 oriented obliquely to the width direction x and the vertical direction y.

The distributor elements 34, 35 are constructed identically and in particular are arranged in mirror symmetry with respect to the distributor element 33. Each manifold element 34, 35 includes a plurality in the Fig. 3 only schematically indicated ripples or waves 44 to 46, which in the orientation of the Fig. 3 are oriented obliquely to the direction of gravity g. The waves 44 to 46 can also be referred to as ribs, webs or fin webs. The shafts 44 to 46 form a plurality of passages or channels 47, 48 that run obliquely to the direction of gravity g. The channels 47, 48 can be part of the heat transfer passage 32. The distributor elements 34, 35 rest on the side edges 42, 43 of the distributor element 33. Furthermore, the distributor elements 34, 35 rest on a lower edge 49 of the heating surface element 3. The channels 40, 41 of the distributor element 33 are in fluid communication with the channels 30, 31 of the heating surface element 3 via the channels 47, 48 of the distributor elements 34, 35. The distributor elements 33 to 35 can also be referred to as distributor fins.

In the orientation of the Fig. 3 on the underside, the distributor elements 33 to 35 are closed with the aid of sidebars or edge strips 50, 51. The edge strips 50, 51 define an outer surface AF of the heat exchanger block 2, to which the connection device 15 is attached, in particular welded on. The edge strips 7, 8, 50, 51 thus run around the heating surface element 3 and the distributor elements 33 to 35 in a frame shape. The orientation of the Fig. 3 edge strips are also provided on the upper side, but are not shown. The distributor opening 36 is provided between the edge strips 50, 51. The distributor opening 36 can be designed as an opening in the edge strips 50, 51. The connection device 15 is attached to the heat exchanger block 2, for example welded to it, in such a way that the connection device 15 covers the distributor opening 36.

The connection device 15 comprises an interior space I which is delimited in the direction of the heat exchanger block 2 by the outer surface AF thereof. This means that the edge strips 50, 51 are not arranged inside the interior I but outside the interior I.

In the operation of the plate heat exchanger 1, the liquid phase FP of the fluid A is fed to the heat exchanger block 2 with the aid of the connection device 15. The connection device 15 distributes the liquid phase FP in the depth direction z to a plurality of heat transfer passages 32 arranged in parallel. Viewed in the width direction x, the distributor elements 33 to 35 distribute the liquid phase FP of the fluid A to the channels 30, 31 of the respective heating surface element 3.

In the production of liquefied natural gas, natural gas is cooled down and liquefied as a result. So-called mixed refrigerants can be used for this purpose. After the expansion to operating pressure, these are two-phase and are separated into a gas phase and a liquid phase upstream of the plate heat exchanger 1.

For example, fluid A is such a mixed refrigerant. At least one of the fluids A to E is natural gas. The liquid phase FP of the fluid A is supplied to the plate heat exchanger 1 in one phase via the connection device 15. In the plate heat exchanger 1, the liquid phase FP of the fluid A is directed upwards, that is, against the direction of gravity g, evaporates and is somewhat overheated by approximately 5 K to 25 K. The gas phase can be led around the plate heat exchanger 1 and mixed downstream of the plate heat exchanger 1 with the now evaporated liquid phase FP. Alternatively, the gas phase can also be fed separately from the liquid phase FP into the plate heat exchanger 1 and mixed with the liquid phase FP within the heat exchanger block 2 and evaporated together with the latter.

Evaporation of the liquid phase FP of the fluid A, which after entering the heat exchanger block 2 forms a two-phase flow which comprises a liquid and a gaseous phase, can lead to the phenomenon of the so-called Ledinegg instability. The Ledinegg instability can be particularly vertical arranged tube, in which the phase boundary of the two-phase current is located. For a given mass flow through the pipe, a total pressure loss per unit length of the pipe is lower in the case in which only the liquid phase is in the pipe compared to the case in which only the gas phase is in the pipe. This is due to the different densities of the liquid phase and the gas phase. If the phase boundary in the pipe now rises, the total pressure drop drops, which can increase the mass flow in an unstable manner.

Transferred to a heat transfer passage 32 of the plate heat exchanger 1, this means that a total pressure loss p ( Fig. 5 ) of the fluid A, which is divided between the channels 30, 31 of the heat transfer passage 32, does not rise monotonously with a mass flow m in the channels 30, 31. The total pressure loss p includes a friction component and a gravitation component. It follows, as in the Fig. 5 shown, a sink in the course of the total pressure loss p over the relative mass flow m. This sink means that, viewed in the width direction x, the desired uniform distribution of the fluid A on the channels 30, 31 of the heat transfer passage 32 is no longer guaranteed, but there are channels 30, 31 with a larger or a smaller mass flow m with the same total pressure loss p .

This unequal distribution can go so far that in some channels 30, 31 the liquid phase FP of the fluid A is no longer completely evaporated and thus exits the heat exchanger block 2 in two phases. The uneven distributions can lead to a thermal underperformance of the plate heat exchanger 1. Furthermore, these can also lead to an uneven temperature profile in the heat exchanger block 2 and thus to thermal voltages. As a consequence, these thermal voltages can lead to leaks. It is therefore important to prevent the occurrence of Ledinegg instability or at least to reduce this phenomenon.

The Fig. 6 and 7 show a training of the in the Fig. 3 and 4th shown plate heat exchanger 1, which is optimized so that no Ledinegg instability occurs. The embodiment of the plate heat exchanger 1 according to the Fig. 6 and 7 differs from the embodiment of the plate heat exchanger 1 according to the Fig. 3 and 4th in that the distributor opening 36 is closed with the aid of pressure loss element 52. The pressure loss element 52 can be constructed analogously to the heating surface element 3 or the distributor elements 33 to 35. That is, the pressure loss element 52 is a fin, in particular a so-called hardway fin. The entire liquid phase FP of the fluid A, which is still single-phase in the region of the distributor opening 36, is passed or forced through the pressure loss element 52.

For this purpose, the pressure loss element 52 is connected to the heat exchanger block 2 in a fluid-tight manner. For example, the pressure loss element 52 with the help of connecting seams 53, 54, in particular with the aid of welded seams or soldered seams, of which in the Fig. 7 only one is shown, welded or soldered into the distribution opening 36. That is, the pressure loss element 52 is arranged within the distributor opening 36 and in particular within the heat exchanger block 2. For example, the pressure loss element 52 can be welded or soldered to the separating plates 4 and the edge strips 50, 51. In particular, the pressure loss element 52 is connected to the heat exchanger block 2 such that no bypass flows occur between the pressure loss element 52 and adjacent components, such as, for example, the separating plates 4 or the edge strips 50, 51.

The pressure loss element 52 is preferably arranged flush with the outer surface AF. That is, the pressure loss element 52, viewed in the vertical direction y, preferably does not protrude beyond the outer surface AF. Alternatively, the pressure loss element 52 can also protrude slightly beyond the outer surface AF. In this case, for example, the pressure loss element 52 can be soldered or welded onto the outer surface AF. As previously mentioned, the interior I of the connection device 15, viewed in the vertical direction y, is delimited by the outer surface AF. That is, the pressure loss element 52 is preferably not arranged inside the interior I but outside the interior I. This enables a very compact structure.

The pressure loss element 52, like for example the heating surface elements 3, can have a plurality of corrugations or shafts 55 to 57 ( Fig. 9 ) which are oriented along the width direction x. In the Fig. 9 are only three shafts 55 to 57 with a reference number Mistake. The waves 55 to 57 can also be referred to as ribs, webs or fin webs. The waves 55 to 57 form a plurality of passages or channels 58, 59 running in the width direction x. The waves 55 to 57 are oriented perpendicularly or transversely to a flow direction DR in which the liquid phase FP of the fluid A flows through the pressure loss element 52 . Under "vertical" or "transverse" is in particular an angle of 90 ° ± 10 °, preferably 90 ° ± 5 °, more preferably 90 ° ± 3 °, more preferably 90 ° ± 1 °, more preferably exactly 90 ° to understand. The shafts 55 to 57 are arranged at a distance a from one another. The distance a can also be called division or fin division. In order to modify the properties of the pressure loss element 52, the distance a can be changed during the production of the pressure loss element 52.

The pressure loss element 52 further includes one in the Fig. 8 Perforation 60 shown through which the liquid phase FP of the fluid A can flow. The perforation 60 comprises a plurality of openings 61 to 63 provided in the pressure loss element 52, of which in the FIG Fig. 8 only three are provided with a reference symbol. The openings 61 to 63 can be bores or punched-outs. The breakthroughs 61 to 63 can break through all the waves 55 to 57. The openings 61 to 63 can be arranged on the shafts 55 to 57 in such a way that the openings 61 to 63, viewed in the vertical direction y, are arranged one behind the other or in the width direction x offset from one another.

To modify the properties of the pressure loss element 52, a cross-sectional area and / or a geometry of the openings 61 to 63 can be changed. In the view of the Fig. 8 The pressure loss element 52 comprises four side edges 64 to 67, which are connected to the heat exchanger block 2 in a fluid-tight manner, in particular welded or soldered. A seal, for example a sealing cord, can also be provided for fluid-tight sealing. The side edges 64 to 67 form an outer contour 68 of the pressure loss element 52.

In particular, the pressure loss element 52 is suitable for generating a pressure loss of 20 mbar to 400 mbar at the distributor opening 36. The pressure loss to be generated can be changed by modifying the perforation 60 and / or by changing the distance a. The in the Fig. 6 shown center The position of the connection device 15 is arbitrary. Each of the other connection devices 9 to 14 and 16 to 18 can also be provided with a pressure loss element 52. In this case, however, the pressure loss element 52 is only provided where the respective fluid A to E enters the heat exchanger block 2 and not where it exits, since the two-phase fluid A to E in question can occur at the outlet.

As the Fig. 10 shows, the pressure loss element 52 generates a total pressure loss p, which has a monotonic course with the relative mass flow m and which in the Fig. 5 shown sink of the course in the two-phase pressure loss converts into a monotonic course. The uniform distribution of the total flow of the liquid phase FP of the fluid A or the proportions thereof to the channels 30, 31 of the heat transfer passage is ensured, the required heat conversion is achieved and the temperature distribution is homogenized.

The Fig. 11 shows a schematic partial sectional view of a further embodiment of a plate heat exchanger 1. The plate heat exchanger 1 according to FIG Fig. 11 differs from the plate heat exchanger 1 according to the Fig. 6 and 7 only in that the pressure loss element 52 is not welded or soldered into the heat exchanger block 2, but is connected to it by means of a tongue and groove system 69. The tongue and groove system 69 comprises grooves 70, 71 provided in the edge strips 50, 51, into which tongue sections 72, 73 provided on both sides of the pressure loss element 52 are inserted. The insertion can take place in the depth direction z. In order to avoid bypass flows, seals, not shown, can be provided. With the help of the tongue and groove system 69, a positive connection between the pressure loss element 52 and the heat exchanger block 2 can be produced. A positive connection is created by the interlocking or engaging of at least two connection partners, in the present case the grooves 70, 71 and the tongue sections 72, 73 of the tongue and groove system 69.

Furthermore, the embodiment of the plate heat exchanger 1 according to the Fig. 6 and 7 with the embodiment of the plate heat exchanger 1 according to the Fig. 11 can be combined so that the pressure loss element 52 in addition to the attachment can still be welded or soldered to the heat exchanger block 2 with the aid of the tongue and groove system 69.

The Fig. 12 shows a schematic block diagram of an embodiment of a method for operating a plate heat exchanger 1 as explained above. In the method, the liquid phase FP of the respective fluid A to E to be evaporated is fed into the heat exchanger block 2 of the plate heat exchanger 1 in a step S1. In a step S2, a pressure loss is generated at the distributor opening 36 with the aid of the pressure loss element 52 arranged at the distributor opening 36 and connected to the heat exchanger block 2. In a further step S3, the liquid phase FP is converted into a two-phase flow during the heat exchange with a fluid A to E to be liquefied within the heat exchanger block 2. The liquid phase FP evaporates at least partially.

The Fig. 13 shows a schematic block diagram of an embodiment of a method for producing a plate heat exchanger 1 as explained above. In a step S10, the heat exchanger block 2 is provided. The provision of the heat exchanger block 2 can include producing, for example soldering individual parts, the heat exchanger block 2. The pressure loss element 52 is provided in a step S20. Providing the pressure loss element 52 may include fabricating the same. For example, when the pressure loss element 52 is provided, the perforation 60 can be introduced into the same. Perforation 60 can be altered to achieve the desired pressure drop. Furthermore, the distance a between the shafts 55 to 57 can also be set to a desired dimension. In a step S30, the pressure loss element 52 is arranged at the distributor opening 36. In this case, the pressure loss element 52 can be placed, for example, on the distributor opening 36 or placed therein. In a step S40, the pressure loss element 52 is connected to the heat exchanger block 2. For example, the pressure loss element 52 can be soldered or welded to the heat exchanger block 2. The pressure loss element 52 can additionally or alternatively be connected to the heat exchanger block 2 in a form-fitting manner with the aid of the tongue and groove system 69.

Although the present invention has been described on the basis of exemplary embodiments, it can be modified in many ways.

References used

1

Plate heat exchanger

2nd

Heat exchanger block

3rd

Heating surface element

4th

Partition plate

5

Cover plate

6

Cover plate

7

Sidebar

8th

Sidebar

9

Connection device

10th

Connection device

11

Connection device

12

Connection device

13

Connection device

14

Connection device

15

Connection device

16

Connection device

17th

Connection device

18th

Connection device

19th

Support

20th

Support

21st

Support

22

Support

23

Support

24th

Support

25th

Support

26

process plant

27th

wave

28

wave

29

wave

30th

channel

31

channel

32

Heat transfer passage

33

Distribution element

34

Distribution element

35

Distribution element

36

Distribution opening

37

wave

38

wave

39

wave

40

channel

41

channel

42

Side edge

43

Side edge

44

wave

45

wave

46

wave

47

channel

48

channel

49

Lower edge

50

Sidebar

51

Sidebar

52

Pressure loss element

53

Connecting seam

54

Connecting seam

55

wave

56

wave

57

wave

58

channel

59

channel

60

perforation

61

breakthrough

62

breakthrough

63

breakthrough

64

Side edge

65

Side edge

66

Side edge

67

Side edge

68

Outer contour

69

Tongue and groove system

70

Groove

71

Groove

72

Spring section

73

Spring section

a

distance

A

Fluid

AF

Outside surface

B

Fluid

C.

Fluid

D

Fluid

DR

Flow direction

E

Fluid

FP

Liquid phase

G

Direction of gravity

I.

inner space

m

Mass flow

p

Total pressure loss

S1

step

S2

step

S3

step

S10

step

S20

step

S30

step

S40

step

x

Width direction

y

Vertical direction

e.g.

Depth direction

Claims (15)

Plate heat exchanger (1) for a process plant (26), with a connection device (9 - 18), in particular an inlet header, for supplying a liquid phase (FP) of a fluid (A - E) to be evaporated to the plate heat exchanger (1), a heat exchanger block (2), which has a distributor opening (36) for distributing the liquid phase (FP) to a heat transfer passage (32) of the heat exchanger block (2), and a pressure loss element (52) which is arranged at the distributor opening (36) and which is connected to the Heat exchanger block (2) is connected to generate a pressure drop when the liquid phase (FP) flows into the heat exchanger block (2). The plate heat exchanger according to claim 1, wherein the pressure loss element (52) is arranged inside the distributor opening (36). Plate heat exchanger according to claim 1 or 2, wherein the pressure loss element (52) is arranged flush with an outer surface (AF) of the heat exchanger block (2). Plate heat exchanger according to claim 3, wherein the connection device (9 - 18) is connected to the outer surface (AF), and wherein the connection device (9 - 18) covers the pressure loss element (52) such that the pressure loss element (52) outside an interior (I ) of the connection device (9-18) is arranged. Plate heat exchanger according to one of claims 1-4, wherein an outer contour (68) of the pressure loss element (52) is fluid-tightly connected to the distributor opening (36). Plate heat exchanger according to one of claims 1-5, wherein the pressure loss element (52) is set up to generate a pressure loss of 20 mbar to 400 mbar. Plate heat exchanger according to one of claims 1-6, wherein the pressure loss element (52) has a perforation (60) through which the liquid phase (FP) flows completely during operation of the plate heat exchanger (1). Plate heat exchanger according to one of Claims 1-7, wherein the pressure loss element (52) has shafts (55-57) arranged parallel to one another and spaced apart from one another, between which channels (58, 59) are provided. Plate heat exchanger according to one of claims 1-8, wherein the pressure loss element (52) is arranged perpendicular to a flow direction (DR) of the liquid phase (FP) through the pressure loss element (52). Plate heat exchanger according to one of claims 1-9, wherein the pressure loss element (52) with the aid of a connecting seam (53, 54) is integrally connected to the heat exchanger block (2), and / or wherein the pressure loss element (52) with the aid of a tongue and groove Systems (69) is positively connected to the heat exchanger block (2). Method for operating a plate heat exchanger (1) for a process plant (26), comprising the steps: a) feeding (S1) a liquid phase (FP) of a fluid (A - E) to be evaporated into a heat exchanger block (2) of the plate heat exchanger (1), b) generating (S2) a pressure loss at a distributor opening (36) of the heat exchanger block (2) with the aid of a pressure loss element (52) arranged on the distributor opening (36) and connected to the heat exchanger block (2), and b) converting (S3) the liquid phase (FP) into a two-phase flow within the heat exchanger block (2) during a heat exchange with a fluid to be liquefied (A - E). The method of claim 11, wherein in step b) a pressure loss of 20 mbar to 400 mbar is generated. Method for manufacturing a plate heat exchanger (1) for a process plant (26), comprising the steps: a) providing (S10) a heat exchanger block (2), b) providing (S20) a pressure loss element (52), c) arranging (S30) the pressure loss element (52) on a distributor opening (36) of the heat exchanger block (2), and c) connecting (S40) the pressure loss element (52) to the heat exchanger block (2). The method of claim 13, wherein a perforation (60) is introduced into the pressure loss element (52) before or in step b). The method according to claim 13 or 14, wherein a distance (a) from adjacent shafts (55-57) of the pressure loss element (52) is set before or in step b).

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