WO2007025766A1

WO2007025766A1 - Heat exchanger device for the rapid heating or cooling of fluids

Info

Publication number: WO2007025766A1
Application number: PCT/EP2006/008564
Authority: WO
Inventors: Rolf Dahlbeck; Marcel Dierselhuis
Original assignee: Syntics Gmbh
Priority date: 2005-09-01
Filing date: 2006-09-01
Publication date: 2007-03-08
Also published as: DE202005013835U1; JP2009507202A; CA2600057A1; US20080190594A1; EP1920208A1; AU2006286714A1; IL185605A0

Abstract

Disclosed is a heat exchanger (1) composed of a stack of foils or plates (F), particularly a micro heat exchanger. Breakthroughs (4, 5, 7, 8) and ducts (2, 3) that extend on the level of the plate are configured in the individual plates (F). The plates (F) are placed on top of each other in such a way that the ducts (2, 3) intersect in successive plates (F), a first fluid (P) flows through the ducts (2) of one plate (F) while a second fluid (W) flows through the ducts (3) of the adjacent plate (F), feeding tubes and discharge tubes are embodied on the external faces of the resulting blocks of intersecting ducts (2, 3) by means of the breakthroughs (4, 5, 7, 8), and at least one of the two fluids (P, W) flows through the ducts of the respective plate antiparallel to one another or alternately in opposite directions.

Description

Heat exchanger device for rapid heating or cooling of fluids

The invention relates to a heat exchanger device with which fluids can be cooled or heated very quickly and with great uniformity.

Heat exchangers are needed in numerous industrial applications. At the same time, the trend towards ever higher heat transfer rates in a small space is increasing. These requirements are met in particular by micro-heat exchangers. In the process technology, it is also desired that the heat transfer is very uniform, d. H. that no so-called. "hot spots" (hot zones) arise, which can lead to product damage due to an uncontrolled increase in temperature.

A microstructured heat exchanger is known from DE 100 22 972 A1, which is composed of small tubes or hollow fibers which are located in a graphite matrix.

Furthermore, micro-heat exchangers are also constructed from multiple layers of microstructured layers, the individual layers each having a number of microchannels. The layers are arranged so that the microchannels of adjacent layers are aligned in a simple cross-flow construction, DC construction or countercurrent construction. Such a micro heat exchanger is known from DE 196 08 824 A1.

The countercurrent heat exchanger achieves the highest heat exchange capacity per exchange surface. However, it can not be ruled out that inadmissibly high temperature differences can occur at the inlet of the warmer fluid, which leads to damage to the fluid to be heated.

In the case of the DC heat exchanger, in turn, the wall temperatures remain in a central region at all points of the heating surface. Due to the rapidly decreasing Temperature difference between the adjacent fluids, the heat exchange performance, however, is relatively poor.

In simple cross-flow heat exchangers, as currently known in micro heat exchangers, the heat exchange rates are between those of the DC heat exchanger and the countercurrent heat exchanger. However, here the full heat exchange surface is not used efficiently because the temperature differences in a quadrant of the heat exchange surface are extremely small or no longer exist.

Furthermore, the known micro-heat exchanger no sufficient or no thermal insulation to the environment, which is particularly in modular microreaction systems, as they are, for. B. from DE 202 01 753 Ul, very detrimental effect, because it comes to an intensive heat exchange with adjacent modules.

The invention is based on the object, with the highest possible heat transfer performance, d. H. the creation of a large heat transfer surface to achieve an extremely low pressure drop for both the process fluid and the heat transfer fluid.

This is inventively achieved in that the heat exchanger is constructed of a stack of films or plates, in each of which adjacent channels for the fluids are formed, wherein the channels of the superimposed films or plates intersect. The heat transfer fluid flows in the adjacent channels of a film or plate in partial streams in anti-parallel to each other, while in the overlying and underlying film or plate, the process fluid flows transversely to the heat transfer fluid in parallel in the adjacent channels. By each straight channel guide the pressure drop in the heat exchanger is minimized.

With the device according to the invention, the inlet conditions of each partial flow of the process fluid over the entire volume of the heat exchanger are produced at each crossing point of heat transfer fluid and process fluid Countercurrent heat exchanger with the known high temperature differences between heat transfer fluid and process fluid. Due to the numerous points of intersection of heat transfer fluid and process fluid, this results in an optimum temperature difference between heat transfer fluid and process fluid over the entire volume of the heat exchanger and thus an extremely high heat transfer performance per unit volume and at the same time an absolutely uniform heat transfer over the entire volume of the heat exchanger.

With the present invention, on the one hand, the advantages of a countercurrent heat exchanger are combined with the advantages of a crossflow heat exchanger.

Reference to the drawing, the invention is explained in more detail below, for example.

Show it:

1 shows a schematic cross section through a film stack,

2 shows a section along the line A-A in Fig. 1,

3 is a section along the line C-C in Fig. 1 and Fig. 2,

4 is a section along the line B-B in Fig. 1,

5 schematically shows the flow pattern in two superimposed layers of flow paths,

6 shows a schematic, perspective view of the arrangement of channels and lines of the heat exchanger,

7 is an exploded view of distribution plates,

8 is a cutaway perspective view of a housing with a micro heat exchanger from a film stack and

FIG. 9 schematically shows a grouping of a plurality of heat exchanger units according to FIG. 6, which form a heat exchanger of greater capacity.

Figs. 1 to 4 show schematically the structure of a micro heat exchanger 1, wherein Fig. 1 shows a stack of sheets or thin plates F, as indicated by dashed lines in Fig. 1. In the individual foils of the plates are channels and openings formed, wherein the horizontally extending channels may be formed in a film F, for example, by depressions, which are covered by the surface of the adjacent film F, so that there is a closed channel. In the exemplary embodiment according to FIG. 1, the lowermost film of the film stack is merely shown as a cover film for the lower row of channels 3. But it is also another form of channeling in the individual sheets or plates F possible, for example by a dividing line between two adjacent foils F respectively along the center of the horizontally extending channels 2 and 3 extends.

1 shows, as an example, a flow pattern in which a process fluid P flows through the channels 2 and a heat transfer fluid W flows through the channels 3 extending transversely thereto. The channels 3 are juxtaposed in a film F and form a row 30 of channels in every other film F. In the same way, the channels 2 for the process fluid P are arranged side by side, each in a row 20, as shown in FIG. showing a section along the line AA in Fig. 1. The process fluid P flows in parallel through the adjacent channels 2, while the heat transfer fluid W in two partial streams Wi and W _{2 flows} antiparallel through the adjacent channels 3, as schematically shows the flow pattern in Fig. 5. The antiparallel flow of the partial flows of the heat transfer fluid can also be seen from Fig. 4, which shows a section along the line BB in Fig. 1, Fig. 4 shows only a partial section and the top and bottom edge portions of the heat exchanger unit 1 are not reproduced.

The supply of the heat transfer fluid W via openings 4 in the sheets F, which form a line 4 in FIG. 2 from bottom to top, which extends approximately at an angle of 90 ° transverse to the horizontally extending channels 2 and 3. The discharge of the heat transfer fluid W takes place on the opposite side by a line 4a, which is formed by corresponding openings in the superimposed films F and also in the plane of FIG. 2 from top to bottom or vice versa respectively transverse to the channels 2 and 3 runs. The adjacent in Fig. 2 channels 3, flow through the partial streams W ₂ from right to left, are supplied by a formed by apertures 5 line, which lies in front of and behind the line 4a. The removal of the partial streams W ₂ is carried out by lines 5a in front of and behind the line 4 in Fig. 2, as can be seen also from Fig. 6. Fig. 1 shows in the same way through openings formed lines 7 and 8 on the opposite sides of the intersecting channels 2 and 3, wherein in the illustrated embodiment, the process fluid P is supplied from above through the line 7 and discharged through the line 8.

To clarify the flow pattern, the flow direction is represented by X in Fig. 1 to 4 away from the viewer and by a point the flow direction to the viewer.

Fig. 5 shows schematically the flow pattern in the core region of the heat exchanger with intersecting channels 2 and 3, wherein the heat transfer fluid W in the first upper row 30 of channels 3 in Fig. 1 and the process fluid P in the underlying row in FIG of channels 2, without reproducing the channels themselves. Thus, FIG. 5 shows the flow in the core region of the heat exchanger only by arrows, with the process fluid P flowing in parallel through the channels 2 arranged in rows and the heat transfer fluid W transversely thereto in each case in antiparallel flow of the partial streams Wi and W ₂ .

Fig. 6 shows in a schematic perspective view of a heat exchanger unit 1. The core of the heat exchanger is formed by the intersecting channels 2 and 3, which are each arranged in rows 20 and 30, wherein the heat transfer fluid W in adjacent channels 3 antiparallel or in Countercurrent is guided while the process fluid P flows in DC through the adjacent channels 2. The fluid supply and removal takes place in each case on the outer sides of the block-shaped arrangement of the intersecting channels 2, 3 by lines which are formed by the apertures 4, 5 and 7, 8 in the films F. Thus, the heat exchange in the inner block of intersecting channels 2,3, while the supply and discharge lines are arranged 4.5 and 7.8 on the outside of the block.

In Fig. 6, the reproduced in Fig. 1 and 3 lines 6 are not shown on opposite outer sides of the heat exchanger 1. If, in an alternative embodiment, the micro-heat exchanger 1 is used for cooling a process fluid P, the heat-transfer fluid W first flows through openings 6, which are formed in FIG. 1 on the outside of the supply and discharge lines 7 and 8 for the process fluid P, so that through these lines 6 with cold heat transfer fluid W an efficient thermal insulation of the warm process fluid P in the channels 7 and 8 is achieved with respect to the environment. Subsequently, the heat transfer fluid W is supplied through the apertures 4 to the channels 3 running out of the drawing plane in FIG. 2 through a line guide, not shown, on the upper and lower side in FIG. 1, after which the heat transfer fluid exits via the lines formed by the apertures 8 , In this embodiment, the block of intersecting channels 2 and 3 on the four outer sides is insulated from the environment by a series of conduits 6, only two outer sides being shown in FIG. The outer sides of the heat exchanger core located at the top and at the bottom in FIGS. 1 and 2 are also formed by rows 30 of the channels 3, through which the heat transfer fluid W flows. In this way, the process fluid P to be cooled in the channels 2, 7 and 8 is effectively shielded from the environment.

If the micro-heat exchanger 1 is used for heating a process fluid P or as an evaporator, then the feeds of the heat-transfer fluid W and of the process fluid P can be exchanged so that in this case too the colder fluid flows into the external lines 6, 7 and 8, so that a thermal insulation is given to the environment. Here, the design is chosen so that the arranged on the outer sides channel rows 30 are also flowed through by the colder fluid.

The structure described allows for a variety of customization options by changing the number of films F and the channels 2, 3 and adapted to the respective desired flow rates. By increasing the stack of films or thin plates F, the capacity of the micro heat exchanger 1 can be increased accordingly. It is also possible to flow both the process fluid P and the heat transfer fluid W antiparallel through the respective rows 20, 30 of channels 2, 3. It may also be advantageous to allow only the process fluid P to flow antiparallel or in countercurrent through the adjacent channels 2, while the heat transfer fluid W flows transversely thereto in one direction in the channels 3.

The channels 2,3 and the lines 4 to 8 can be designed so that they have the same cross section throughout. This results in a minimal pressure drop in the flow through the heat exchanger. But it is also possible to make the lines 4 to 8 larger in cross-section than the channels 2 and 3.

8 schematically shows a film stack FS in a housing 100, in which lines for the supply and discharge of process fluid P and heat transfer fluid W are formed. As shown, the housing Io0 is constructed as a module which can be combined with other modules for the treatment of a process fluid P. However, the heat exchanger 1 described with reference to FIGS. 1 to 4 can also be used without a housing 100, wherein in Fig. 1 on the upper and lower side in each case a device for routing is provided which the connections for the lines 4, 5, 6 , 7 and 8 have.

Fig. 7 shows in an embodiment distributor plates or foils Fl to F3 in an exploded view, which shows the supply of the heat transfer fluid W from the bottom of a film stack and the division into the partial streams Wi and W ₂ . In the bottom film F 1, an opening 10 is formed through which the heat transfer fluid W is supplied. From the aperture 10, a channel 10a extends in the film plane, which divides into two channels 10b, which in turn split into two channels 10c and so on, until on the right side in Fig. 7, the number of lines 10e is available , which is required for the supply of the channels 3 of a row 30 for the heat transfer fluid in the core region of the heat exchanger. In the overlying film F2 openings 5 are formed in a row, which are opposite to the ends of the individual lines 1 Oe, so that the heat transfer fluid W, as indicated by dashed line, can flow up through the openings 5. In the film F 2, a branching line 11 is formed on each second opening 5, which in the film plane to the opposite side the core region of the heat exchanger unit 1 leads. In the overlying film F3 a series of openings 4 is formed, which lie opposite the ends of the lines 11, so that a partial flow Wi of the heat transfer fluid can flow through the openings 4 upwards. The opposite row of apertures 5 in the film F3 is opposite to the apertures 5 in the film F2, of which no lines branch off 11, so that through the apertures 5, a partial stream W ₂ flows upwards.

Over the film F3, a channel arrangement according to FIG. 4 may be formed in the next film plane in which the two partial streams Wi and W ₂ flow in countercurrent through the channels 3. For ease of illustration, the return lines 4a and 5a are not shown in the films Fl to F3. They can be formed by corresponding openings in the films, wherein according to the films Fl and F2 the back-flowing heat transfer fluid W is collected and discharged through a common outlet corresponding to the opening 10.

The supply of the process fluid P in the illustrated embodiment is carried out from above by an arrangement of distributor plates corresponding to that shown in Fig. 7, wherein the bottom in Fig. 7 plate Fl forms the top plate for the supply of the process fluid. Since the process fluid P flows through the channels 2 in DC, it is not necessary to provide a distributor plate corresponding to the distributor plate F2. On the contrary, a film with openings corresponding to film F3, in which rows of openings 7 and 8 are formed, instead of the row of openings 4 and 5 shown in FIG. 7, can adjoin the uppermost film corresponding to the film F1.

In the illustration in Fig. 7, the lines lying in Fig. 1 and 3 6 are not shown to simplify the illustration, which are also formed by openings in the individual foils F.

In Fig. 7, the films Fl to F3 are disc-shaped, while in Figs. 1 to 4 and 6 each only a block-shaped arrangement of channels 2,3 and lines 4 to 8 is shown. The channels and lines shown in these figures can be found in the be formed in the same manner in disc-shaped films, so that a round stack FS of films F results, as shown in Fig. 8.

In the heat exchanger unit shown in Fig. 8, the heat transfer fluid W is supplied from below and discharged upward so that any air contained in the heat exchanger is pushed up. The process fluid can be supplied from above and discharged on the bottom again. However, another flow direction of the fluids P and W is also possible. Thus, the heat transfer fluid W can be supplied from above and also discharged upward again, while the process fluid P is supplied from below and discharged down.

FIG. 9 schematically shows a grouping of individual heat exchanger units 1, one of which is shown in FIG. For very large heat transfer capacities or large fluid flows, a plurality of such heat exchanger units 1 can be arranged side by side and one above the other, as shown in FIG. 9, wherein a further layer of heat exchanger units 1b and 1c is arranged above a lower layer of heat exchanger units 1a. Thereby, the heat transfer performance can be multiplied without substantially increasing the total pressure drop by the individual heat exchanger units 1 are supplied in parallel fluidly. In other words, each individual heat exchanger unit 1 can be supplied with fluid via distributor plates according to FIG. 7, wherein the various distributor plates can be centrally supplied with fluid by means of an additional distributor plate. Between the individual layers of heat exchanger units Ia. Ib and Ic can be provided distributor plates in which openings are formed for the formation of vertical between the heat exchanger units Ia upwardly leading lines through which the heat exchanger units Ib and Ic are supplied with the fluids W and P. Similarly, manifold plates may be provided on the top of the block from a plurality of heat exchanger units.

According to a simpler embodiment, only a group of heat exchanger units Ia can be supplied in parallel to increase the heat transfer capacity, which corresponds to the lower layer in FIG. In such a configuration, in addition to the reproduced in Fig. 7 distribution plates on the top and Bottom another distributor plate are provided, from which the individual apertures 10 are supplied with fluid, said additional distributor plate having a central fluid supply of the channels to the individual openings 10 of the individual heat exchanger units Ia lead away according to the reproduced in Fig. 7 film Fl.

To determine the temperature of the fluids, temperature sensors can advantageously be integrated in the immediate vicinity of the microstructured films or thin plates.

The term fluid or process fluid is to be understood according to the invention and includes both liquids and gases as well as emulsions, dispersions and aerosols. The device can be used both for cooling and for heating

Microstructured channels are structures that are smaller than 1 mm in at least one spatial dimension. The walls between the microstructured channels are preferably between 10 μm and 500 μm thick.

Advantageously, the films or thin plates from which the micro heat exchanger is joined together consist of sufficiently inert material, preferably metals, semiconductors, alloys, stainless steels, composite materials, glass, quartz glass, ceramics or polymer materials or combinations of these materials.

As a suitable method for fluidly sealing the films or thin plates come z. As pressing, riveting, gluing, soldering, welding, diffusion soldering, diffusion bonding, anodic or eutectic bonding in question.

The structuring of the films or thin plates can, for. B. carried out by milling, laser ablation, etching, the LIGA-V experienced, galvanic molding, sintering, stamping or deformation. For the skilled person it is easy to understand that the device can not only be used as a micro heat exchanger, but z. B. also use as an evaporator or condenser as in their combination (rectification) is possible.

Furthermore, the structure of a heat exchanger according to the invention is not only suitable for the microstructure. It can also be used for larger sized heat exchangers. These may e.g. be constructed of thicker plates in which punched channels, milled or stamped and formed instead of openings holes. Such structures can also be formed by spark erosion on the plates.

The material of the plates or foils F preferably consists of inert material or of the fluids used with respect to sufficiently inert material.

Claims

claims

1. Heat exchangers (1) constructed from a stack of foils or plates (F), in particular micro-heat exchangers, wherein apertures (4, 5, 7, 8) and channels (2, 3) running in the plate plane are formed in the individual plates (F) and the plates (F) are arranged one above the other in such a way that the channels (2, 3) intersect in successive plates (F), a first fluid (P) through the channels (2) of one plate (F) and a second one Fluid (W) flows through the channels (3) in the adjacent plate (F), on the outsides of the resulting block of intersecting channels (2,3) supply and discharge lines through the apertures (4,5,7,8 ), and wherein at least one of the two fluids (P, W) flows antiparallel or alternately in the opposite direction through the channels of the relevant plate.

2. A heat exchanger according to claim 1, wherein the channels (2, 3) are each juxtaposed in rows (20, 30) are arranged in a plate, and on the outer sides of the block of intersecting channels (2,3) rows of feed and Outlet lines through the openings (4,5,7,8) are formed.

3. Heat exchanger according to claim 1 or 2, wherein at least on two opposite outer sides of the block of intersecting channels (2,3) and on the outer sides of the supply and discharge lines (7,8) each have a series of lines (6) through openings is formed in the individual foils or plates (F), through which one of the fluids for thermal insulation of the other fluid flowing in the heat exchanger (1) flows with respect to the environment.

4. Heat exchanger according to one of the preceding claims, wherein at the top and bottom of the stack of sheets or plates (F) distribution plates (F1-F3) are arranged, through which a central feed (10) of the fluid (P; W) in Split sub-channels and through openings (4,5) to the individual channels (2,3) in the plates (F) is passed.

5. Heat exchanger according to one of the preceding claims, wherein the stack of films or thin plates (F) in a housing (100) is arranged, which is provided with supply and discharge lines for the two fluids (W, P).

6. Heat exchanger according to one of claims 1 to 4, wherein a plurality of heat exchangers (1) 2x1 a group are summarized in a block and each individual heat exchanger (1) separately with the two fluids (W, P) is supplied by a common supply line distributed on the individual heat exchanger (1) and is discharged through a common discharge line.

7. Heat exchanger according to one of the preceding claims, wherein the films or plates (F) are made from respect to the fluids sufficiently inert material.