A plate-fin heat exchanger

Abstract

The present invention relates to a plate-fin heat exchanger, comprising a bottom surface and a sealing box, wherein the left and right ends of the bottom surface are both connected with side surfaces, and the upper and lower ends of the bottom surface are both installed with end plates, the sealing box is located on the outside of the end plate, and the upper left end of the side surface is installed with a high-pressure working medium inlet, the lower right end of the side surface is connected with a high-pressure working medium outlet, and the middle part of the bottom end of the sealing box is connected with a low-pressure working medium inlet. The beneficial effects of the present invention are as follows: in the plate-fin heat exchanger, the high-pressure working medium is input from the high-pressure working medium inlet on the side of the shell, and flows to the high-pressure working medium outlet along the high-pressure working medium channel in the heat exchange plate bundle; then, the low-pressure working medium is input from the low-pressure working medium inlet of the sealing box to the sealing box, and then enters the low-pressure working medium channel in the heat exchange plate bundle and flows to the low-pressure working medium outlet; it is ensured that the heat exchange plate pair is always under the action of positive pressure difference (external pressure is greater than internal pressure), so that the heat exchange plate pair is in a compressive stress state, and the integrity of the pressure boundary between the high-pressure working medium and the low-pressure working medium is maintained.

Description

Technical Field

[0001] The invention relates to the technical field of plate-fin heat exchangers, in particular to a plate-fin heat exchanger. Background Art

[0002] Plate-fin heat exchangers are usually composed of baffles, fins, seals, and guide vanes. Fins, guide vanes, and seals are placed between two adjacent baffles to form a sandwich called a channel. Such sandwiches are stacked up according to different fluid patterns and brazed into a whole to form a plate bundle, which is the core of the plate-fin heat exchanger.

[0003] General plate-fin heat exchangers cannot be tested according to standards, manufacturing costs cannot be effectively controlled, and positive pressure difference design is not adopted. The heat exchange plate is not under external pressure, and the reliability is lower than the internal pressure stress state of the diffusion welded printed circuit board heat exchanger. The welding of the heat exchange plate bundle and the bottom of the shell cannot enhance the bearing pressure of the shell. The regular shape of the heat exchanger is not conducive to reducing space occupancy when multiple modules are combined. Summary of the invention

[0004] The object of the present invention is to provide a plate-fin heat exchanger to solve the problems mentioned in the above background technology that the general plate-fin heat exchanger cannot be tested according to the standard, the manufacturing cost cannot be effectively controlled, and the positive pressure difference design is not adopted. The heat exchange plate pair is not in an external pressure stress state, and the reliability is lower than the internal pressure stress state of the diffusion welding printed circuit board heat exchanger. The welding of the heat exchange plate bundle and the bottom surface of the shell cannot enhance the bearing pressure of the shell. The shape of the heat exchanger is regular, which is not conducive to reducing space occupancy when multiple modules are combined.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a plate-fin heat exchanger, comprising a bottom surface and a sealing box, the left and right ends of the bottom surface are connected with side surfaces, and the upper and lower ends of the bottom surface are installed with end plates, the sealing box is located on the outside of the end plate, and the upper left end of the side surface is installed with a high-pressure working fluid inlet, the lower right end of the side surface is connected with a high-pressure working fluid outlet, the middle of the bottom end of the sealing box is connected with a low-pressure working fluid inlet, and the middle of the top end of the sealing box is provided with a low-pressure working fluid outlet, the bottom surface is connected with a heat exchange plate bundle, and the heat exchange plate bundle is provided with a heat exchange plate pair, the heat exchange plate is installed inside the heat exchange plate pair, and a channel is passed through the middle of the heat exchange plate, the channels are connected with ribs, and the two side edges of the two heat exchange plates of the heat exchange plate pair are welded and sealed, and the outer side of the bottom surface is connected with a tensioning bolt.

[0006] Preferably, two bottom surfaces are provided, and the bottom surface is a flat plate, and the side surface is a semicircular cylinder.

[0007] Preferably, the heat exchange plate bundle and the bottom surface are connected by welding.

[0008] Preferably, the heat exchange plates are arranged in mirror symmetry, and channels and ribs are provided on the front and back sides of the heat exchange plates.

[0009] Preferably, the hydraulic diameter of the heat exchange plate bundle is 1-2 mm, and the gaps through which the heat exchange plates pass through the end plates are sealed by welding.

[0010] Preferably, inlets and outlets are provided through gaps between the two ends of the heat exchange plate bundle and the end plates.

[0011] Preferably, the channels and ribs of the heat exchange plate are manufactured by precision casting, machining, chemical etching and other processes, and the channels and ribs are straight or wavy.

[0012] Preferably, the bottom of the shell is fixedly connected to the heat exchange plate bundle perpendicularly by tightening bolts.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. First, the high-pressure working fluid is input from the high-pressure working fluid inlet on the side, and flows along the high-pressure working fluid channel in the heat exchange plate bundle to the high-pressure working fluid outlet; then, the low-pressure working fluid is input from the low-pressure working fluid inlet of the sealing box to the sealing box, and then enters the low-pressure working fluid channel in the heat exchange plate bundle and flows to the low-pressure working fluid outlet; ensure that the heat exchange plate pair is always under the action of positive pressure difference (external pressure is greater than internal pressure), so that the heat exchange plate pair is in a compressed stress state, and the integrity of the pressure boundary between the high-pressure working fluid and the low-pressure working fluid is maintained; the bottom and side surfaces bear the pressure of the high-pressure working fluid, the sealing box bears the pressure of the low-pressure working fluid, and the end plate bears the pressure difference between the high-pressure and low-pressure working fluids; during the flow process, the high-pressure working fluid and the low-pressure working fluid transfer heat through the heat exchange plate; at the end of the heat exchanger operation, the low-pressure side pressure is first unloaded, and then the high-pressure side pressure is unloaded, ensuring that the heat exchange plate pair is always under the action of positive pressure difference, and the flow of high-pressure and low-pressure working fluids in the heat exchange plate bundle is full countercurrent.

[0015] 2. A compact heat exchanger without diffusion welding is realized, and its compactness is basically close to that of a printed circuit board heat exchanger. Since the material selection of the heat exchange plate is not restricted by the diffusion welding process, there are more optional material grades, and the processing and manufacturing adopt mature and low-cost processes. The products can be tested according to standards, and the manufacturing cost can be effectively controlled. The positive pressure difference design is adopted, and the heat exchange plate pair is in an external pressure stress state, and the reliability is higher than the internal pressure stress state of the diffusion welding printed circuit board heat exchanger. The welding of the heat exchange plate bundle and the bottom surface of the shell greatly enhances the bearing pressure of the shell. The shape of the heat exchanger monomer is regular, which is convenient for reducing space occupancy when multiple modules are combined. The plate-fin heat exchanger is used for the regenerator of the supercritical carbon dioxide cycle, with a maximum pressure of 30MPa and a maximum temperature of 600℃. It is made of heat-resistant alloy steel or stainless steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1This is a schematic diagram of the appearance structure of the plate-fin heat exchanger of the present invention;

[0017] Figure 2 It is a schematic diagram of the internal cross section of the plate-fin heat exchanger of the present invention;

[0018] Figure 3 It is a cross-sectional schematic diagram of a heat exchange plate pair of the present invention;

[0019] Figure 4 It is a schematic diagram of the heat exchange plate structure of the present invention (front and back sides);

[0020] Figure 5 is a schematic cross-sectional view of an end plate of the present invention;

[0021] Figure 6 It is a schematic diagram of the tension bolts arranged outside the plate-fin heat exchanger of the present invention.

[0022] In the figure: 1. bottom surface; 2. side surface; 3. end plate; 4. sealing box; 5. high-pressure working fluid inlet; 6. high-pressure working fluid outlet; 7. low-pressure working fluid inlet; 8. low-pressure working fluid outlet; 9. heat exchange plate bundle; 10. heat exchange plate pair; 11. heat exchange plate; 12. channel; 13. rib; 14. tightening bolts. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0024] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] See also Figure 1-6 The present invention provides a technical solution: a plate-fin heat exchanger, comprising a bottom surface 1, a side surface 2, an end plate 3, a sealing box 4, a high-pressure working medium inlet 5, a high-pressure working medium outlet 6, a low-pressure working medium inlet 7, a low-pressure working medium outlet 8, a heat exchange plate bundle 9, a heat exchange plate pair 10, a heat exchange plate 11, a channel 12, a rib 13, and a tightening bolt 14. The left and right ends of the bottom surface 1 are connected with the side surface 2, and the upper and lower ends of the bottom surface 1 are installed with the end plate 3. The sealing box 4 is located on the outside of the end plate 3, and the side surface 2 A high-pressure working medium inlet 5 is installed at the upper left end, a high-pressure working medium outlet 6 is connected to the lower right end of the side 2, a low-pressure working medium inlet 7 is connected to the middle of the bottom end of the sealing box 4, and a low-pressure working medium outlet 8 is arranged at the middle of the top of the sealing box 4, a heat exchange plate bundle 9 is connected to the bottom surface 1, and a heat exchange plate pair 10 is arranged on the heat exchange plate bundle 9, and a heat exchange plate 11 is installed on the heat exchange plate pair 10, and channels 12 are provided on both sides of the heat exchange plate 11, and the channel 12 is connected with a rib 13, and a tension bolt 14 is connected to the outer side of the bottom surface 1;

[0027] Furthermore: the high-pressure working medium and the low-pressure working medium are in full countercurrent in the heat exchange plate bundle 9. The hydraulic diameter of the channel 12 of the heat exchange plate 11 is selected to be 1 to 1.5 mm;

[0028] according to Figure 2 , a heat exchange plate bundle 9 is arranged between the bottom surfaces 1, the heat exchange plate bundle 9 is welded to the two bottom surfaces 1, and the edges of both sides of the two heat exchange plates 11 of the heat exchange plate pair 10 are welded and sealed;

[0029] according to Figure 3 , the two heat exchange plates 11 are attached to each other and are arranged in mirror symmetry, a low-pressure fluid channel 12 is formed inside the heat exchange plate pair 10, and a high-pressure fluid channel 12 is formed between the heat exchange plate pairs 10;

[0030] according to Figure 4 , adjacent channels 12 are separated by ribs 13, and channels 12 are formed between adjacent ribs 13. Channels 12 and ribs 13 are processed by chemical etching process. Both ends of heat exchange plate 11 pass through end plate 3. Appropriate gaps are reserved between both ends of heat exchange plate 11 and shell 15 and end plate 3 as inlet and outlet of low-pressure fluid entering channels 12 between heat exchange plate pair 10;

[0031] according to Figure 5 , the heat exchange plate bundle 9 passes through the end plate 3, and the gap between the heat exchange plate pair 10 and the end plate 3 is sealed by welding;

[0032] according to Figure 6 , the direction of the tightening bolt 14 is perpendicular to the heat exchange plate bundle 9, and the fixings at both ends of the tightening bolt 14 are welded to the bottom surface 1;

[0033] The working method of the above plate-fin heat exchanger is as follows:

[0034] First, high-pressure carbon dioxide is input from the high-pressure working medium inlet 5 and flows along the high-pressure carbon dioxide channel 12 in the heat exchange plate bundle 9 to the high-pressure working medium outlet 6; then, low-pressure carbon dioxide is input from the low-pressure working medium inlet 7 of the sealing box 4 and flows along the low-pressure channel 12 in the heat exchange plate bundle 9 to the low-pressure working medium outlet 8; ensure that the heat exchange plate pair 10 is always under the positive pressure difference, so that the heat exchange plate pair 10 is in a compressed stress state, and the integrity of the pressure boundary between the high-pressure carbon dioxide and the low-pressure carbon dioxide is maintained; the bottom surface 1 and the side surface 2 bear the pressure of the high-pressure carbon dioxide, the sealing box 4 bears the pressure of the low-pressure carbon dioxide, and the end plate 3 bears the pressure difference between the high-pressure and low-pressure carbon dioxide; during the flow process, the high-pressure carbon dioxide and the low-pressure carbon dioxide transfer heat through the heat exchange plate 11; at the end of the work, the low-pressure side pressure is first unloaded, and then the high-pressure side pressure is unloaded, ensuring that the heat exchange plate pair 10 is always under the positive pressure difference. The flow direction of the high-pressure and low-pressure carbon dioxide in the heat exchange plate bundle 9 is countercurrent. By using the plate-fin heat exchanger of the present invention, the heat recovery efficiency of the supercritical carbon dioxide regenerator can reach 95%, thereby ensuring the high efficiency of the cycle.

[0035] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A plate-fin heat exchanger, comprising a bottom surface (1) and a sealing box (4), characterized in that: The left and right ends of the bottom surface (1) are connected to the side surface (2), and the upper and lower ends of the bottom surface (1) are installed with end plates (3). The sealing box (4) is located outside the end plate (3), and the upper left end of the side surface (2) is installed with a high-pressure working medium inlet (5), and the lower right end of the side surface (2) is connected with a high-pressure working medium outlet (6). The middle of the bottom end of the sealing box (4) is connected with a low-pressure working medium inlet (7), and the middle of the top end of the sealing box (4) is provided with a low-pressure working medium outlet (8). The bottom surface (1) is connected to a heat exchange plate bundle (9), and the heat exchange plate bundle (9) is provided with a heat exchange plate pair (10). The heat plate pair (10) is installed with a heat exchange plate (11), and channels (12) are provided on both sides of the heat exchange plate (11), the channels (12) are connected with ribs (13), and the edges on both sides of the two heat exchange plates of the heat exchange plate pair (10) are welded and sealed, the outer side of the bottom surface (1) is connected with a tensioning bolt (14), and an inlet and outlet are penetrated through a gap between the two ends of the heat exchange plate bundle (9) and the end plate (3), the channels (12) and ribs (13) of the heat exchange plate (11) are manufactured by precision casting, machining, chemical etching and other processes, and the channels (12) and ribs (13) are straight or wavy.

2. A plate-fin heat exchanger according to claim 1, characterized in that: The bottom surfaces (1) are provided with two, and the bottom surface (1) is a flat plate, and the side surface (2) is a semicircular cylinder.

3. A plate-fin heat exchanger according to claim 1, characterized in that: The heat exchange plate bundle (9) and the bottom surface (1) are connected by welding.

4. The plate-fin heat exchanger according to claim 1, characterized in that: The heat exchange plate pair (10) is arranged in a mirror-symmetrical manner, and channels (12) and ribs (13) are provided on the front and back sides of the heat exchange plate (11).

5. The plate-fin heat exchanger according to claim 1, characterized in that: The hydraulic diameter of the heat exchange plate bundle (9) is 1 to 2 mm, and the heat exchange plate pair (10) passes through the gap of the end plate (3) and is sealed by welding.

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