A compact, high-efficiency, in-container plate-fin heat exchanger and method

Abstract

The application discloses a compact high-efficiency separation built-in plate-fin heat exchanger, and belongs to the technical field of heat exchange equipment. The device comprises a cylinder body, a plate-fin heat exchanger inside the cylinder body, defoaming heat exchange blades, column tubes, a main pipe and transition joints. The side wall of the cylinder body is provided with a hot fluid inlet pipe and an outlet pipe, and the inlet pipe is higher than the outlet pipe; the inlet pipe is communicated with the main pipe through the transition joint, the main pipe is communicated with a plurality of column tubes, the lower end of the column tube is connected with the head of the plate-fin heat exchanger through an elbow, and the outlet pipe of the heat exchanger is communicated with the hot fluid outlet pipe through another transition joint. The outer wall of the column tube is provided with the defoaming heat exchange blades at the lower part, the defoaming heat exchange blades are provided with vertical downward extending sealing plates at both ends, a gas collection groove is formed between the sealing plates and the defoaming heat exchange blades, and the gas collection groove is used for collecting gas-liquid mixture from the outlet of the plate-fin heat exchanger. The cylinder body is provided with a refrigerant inlet pipe at the bottom and a refrigerant gas phase outlet pipe at the top. The application realizes compact design and high-efficiency separation effect through optimization of pipeline layout and integrated gas-liquid separation structure.

Description

Technical Field

[0001] This invention belongs to the field of heat exchange equipment technology, specifically relating to a compact, high-efficiency, and separate container-integrated plate-fin heat exchanger. Background Technology

[0002] Siphon heat exchangers with built-in plate-fin heat exchangers are widely used in processes such as ethylene separation and LNG liquefaction. Taking an ethylene condenser as an example, its working principle is as follows: Medium-pressure superheated ethylene gas enters the plate-fin heat exchanger channel within the heat exchanger and condenses into a liquid. Simultaneously, upstream high-pressure propylene, after throttling, becomes a gas-liquid two-phase fluid at a temperature of approximately -40°C, which enters the shell side of the heat exchanger as a refrigerant. After gas separation, the refrigerant is led out from the upper outlet, while the liquid accumulates at the bottom of the shell. Once a certain liquid level is reached, it enters the refrigerant channel of the plate-fin heat exchanger (usually a fully open channel with built-in high-efficiency fins). During the heat exchange with ethylene, a siphon circulation is formed, and the gas-liquid mixture is flushed out of the upper part of the heat exchanger and separated in the upper space.

[0003] However, the aforementioned plate-fin heat exchangers built into containers have the following shortcomings in practical applications: 1) Large equipment size: Conventionally, this type of heat exchanger uses a small-diameter outlet pipe, and the outlet pipe is led out from the bottom of the heat exchanger, resulting in the need for a relatively high installation position. Simultaneously, the low density and extremely high volumetric flow rate of refrigerants such as low-pressure propylene require a large separation space on the shell side, further increasing the overall size of the equipment. 2) Poor gas-liquid separation efficiency: The gas-liquid mixture at the outlet of the plate-fin heat exchanger has a certain flow velocity, and the liquid will be ejected to a high position due to inertia. Even with a wire mesh separator installed at the top, it is difficult to effectively capture these droplets, resulting in mist entrainment and adversely affecting the downstream system. 3) Poor adaptability to large temperature difference conditions: Under specific process conditions, if the temperature of the ethylene entering the heat exchanger is too high, the local temperature difference inside the heat exchanger will exceed the allowable upper limit (for plate-fin heat exchangers with two-phase flow heat exchange, this allowable upper limit is 30℃). Although this portion of the sensible heat load is relatively small (approximately 5°C of vapor phase sensible heat), to meet this operating condition, either the heat exchanger's strength needs to be increased, or its service life will be shortened. 4) Inappropriate refrigerant inlet layout: Refrigerants such as propylene are usually located at the top of the shell. Due to the large diameter of the inlet pipe, in order to accommodate the inlet pipe and ensure sufficient separation space, either the equipment size must be increased, or the separation effect must be sacrificed, resulting in incomplete gas-liquid separation.

[0004] Therefore, developing a container-integrated plate-fin heat exchanger that is compact, has high separation efficiency, and can adapt to complex operating conditions has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and to provide a compact, high-efficiency separation container-integrated plate-fin heat exchanger and method.

[0006] The specific technical solution adopted in this invention is as follows:

[0007] In a first aspect, the present invention provides a compact, high-efficiency, and separate container-integrated plate-fin heat exchanger, comprising a cylinder and a plate-fin heat exchanger, demister heat exchange blades, tubes, a main tube, and a transition joint disposed within the cylinder.

[0008] The sidewall of the cylinder is provided with a hot fluid inlet pipe and a hot fluid outlet pipe, with the hot fluid inlet pipe being higher than the hot fluid outlet pipe. One end of the hot fluid inlet pipe is connected to the steel pipe side of the transition joint, and the aluminum pipe side of the transition joint is connected to one end of the main pipe. The other end of the main pipe is connected to several tubes. The lower end of the tubes is connected to the end cap of the plate-fin heat exchanger through an elbow, introducing the hot fluid into the plate-fin heat exchanger. The outlet pipe of the plate-fin heat exchanger is connected to the hot fluid outlet pipe through another transition joint. Defogging heat exchange blades are provided on the lower part of the outer wall of the tubes, and vertically downward extending sealing plates are provided at both ends of the defogging heat exchange blades. The sealing plates and the defogging heat exchange blades form a gas collecting groove for capturing the gas-liquid mixture from the outlet of the lower plate-fin heat exchanger. Several refrigerant inlet pipes are provided at the bottom of the cylinder, and the refrigerant inlet pipes are connected to the inner cavity of the cylinder. Several connected refrigerant gas phase outlet pipes are provided at the top of the cylinder.

[0009] Preferably, the transition joint is a steel-aluminum transition joint, and both the main pipe and the tubing are aluminum tubes.

[0010] Preferably, the tubes are knurled tubes with enhanced heat exchange performance.

[0011] Preferably, the demister heat exchange blades are corrugated aluminum sheets with 2 to 5 bends, each bend angle being 90° to 120°.

[0012] Furthermore, the corrugated aluminum fins are flanged and fixedly connected to the tubes via interference fit; the corrugated aluminum fins at the bottom of the tubes cover the outlet of the plate-fin heat exchanger.

[0013] Furthermore, each fold of the corrugated aluminum sheet is machined with an extension section to form a liquid collection tank.

[0014] Preferably, the sealing plate extends downward below the low operating liquid level to achieve a liquid seal.

[0015] Preferably, the diameter of the refrigerant inlet pipe is less than 1 / 2 of the width of the plate-fin heat exchanger.

[0016] Preferably, the side wall of the cylinder is also provided with a manhole inspection port for easy equipment maintenance.

[0017] Secondly, the present invention provides a heat exchange method utilizing the container-embedded plate-fin heat exchanger described in the first aspect, as follows:

[0018] The hot fluid enters the shell through the hot fluid inlet pipe, passes through the transition joint, main pipe, and tubes in sequence, and then enters the internal core of the plate-fin heat exchanger for heat exchange; after heat exchange, the hot fluid leaves the shell through the transition joint and hot fluid outlet pipe.

[0019] The refrigerant enters the cylinder through the refrigerant inlet pipe at the bottom of the cylinder and exchanges heat with the hot fluid in the core of the plate-fin heat exchanger. After the heat exchange, the heat-absorbing part of the refrigerant evaporates and becomes a gas-liquid two-phase fluid. After passing through the defoaming heat exchange blades and being heated by the tubes, it leaves the cylinder through the refrigerant gas phase outlet pipe.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] (1) The device provided by the present invention can significantly improve the adaptability to large temperature difference conditions: through the tube precooling structure, the temperature of the hot fluid entering the main heat exchanger is effectively reduced, avoiding equipment damage caused by excessive temperature difference.

[0022] (2) The device provided by this invention significantly improves gas-liquid separation efficiency: the corrugated aluminum sheet has 2 to 5 bends, forming a structure similar to a blade separator, which lengthens the fluid flow path and prolongs the gravity separation time; a liquid collection tank is set at the lower end of the corrugated aluminum sheet to guide the separated liquid to an area outside the upper surface of the heat exchanger, preventing secondary liquid entrainment; a sealing plate is set around the corrugated aluminum sheet to form a gas collection tank, which wraps the siphon outlet of the heat exchanger, and the lower liquid seal ensures that all gas-liquid two-phase fluids are separated by the corrugated aluminum sheet and the tubes, eliminating the phenomenon of flow deviation. The above structure can replace or simplify the upper wire mesh separator and completely solve the problems of liquid jetting and mist entrainment.

[0023] (3) The device provided by the present invention achieves compactness and miniaturization of equipment: by optimizing the layout of the hot fluid inlet pipe in the upper space and moving the refrigerant inlet pipe to the lower part and using its flow channel as part of the separation path, the space utilization rate inside the cylinder is greatly improved, creating conditions for reducing the size of the equipment.

[0024] (4) The device provided by the present invention comprehensively improves the heat exchange performance: the combination of tubes and corrugated aluminum sheets increases the heat exchange area, the optimized refrigerant distribution enhances boiling heat exchange, and finally improves the overall heat transfer efficiency. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the container-integrated plate-fin heat exchanger provided in this embodiment;

[0026] Figure 2 This is a side view of the container-integrated plate-fin heat exchanger provided in this embodiment;

[0027] Figure 3This is a partial enlarged view of the demister heat exchange blades provided in this embodiment;

[0028] In the diagram: 1. Shell; 2. Plate-fin heat exchanger; 3. Refrigerant inlet pipe; 4. Manhole inspection port; 5. Refrigerant vapor phase outlet pipe; 6. Defoaming heat exchange blades; 7. Tube set; 8. Main pipe; 9. Transition joint; 10. Hot fluid inlet pipe; 11. Hot fluid outlet pipe; 12. Sealing plate; 13. Liquid collection tank. Detailed Implementation

[0029] The present invention will be further described and illustrated below with reference to the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly, provided that there is no mutual conflict.

[0030] like Figure 1 and Figure 2 As shown, as a preferred embodiment of the present invention, this embodiment provides a compact, high-efficiency, and separate container-integrated plate-fin heat exchanger. The heat exchanger includes a cylinder 1, and a plate-fin heat exchanger 2, demister heat exchange blades 6, tubes 7, a main pipe 8, and a transition joint 9 disposed within the cylinder 1.

[0031] In the device provided in this embodiment, a hot fluid inlet pipe 10 and a hot fluid outlet pipe 11 are provided on the side wall of the cylinder 1, and the hot fluid inlet pipe 10 is higher than the hot fluid outlet pipe 11 to ensure that the hot fluid flows smoothly under the assistance of gravity.

[0032] In this embodiment, the transition joint 9 is a steel-aluminum transition joint, with one side being a steel pipe and the other side being an aluminum pipe, to achieve a reliable connection between the steel and aluminum pipes. Both the main pipe 8 and the tubes 7 are aluminum pipes to reduce weight and improve thermal conductivity. One end of the hot fluid inlet pipe 10 is connected to the steel pipe side of the transition joint 9, and the aluminum pipe side of the transition joint 9 is connected to one end of the main pipe 8; the other end of the main pipe 8 is connected to several tubes 7. The lower end of the tubes 7 is connected to the end cap of the plate-fin heat exchanger 2 via an elbow, thereby introducing the hot fluid into the plate-fin heat exchanger 2 for heat exchange. The outlet pipe of the plate-fin heat exchanger 2 is connected to the hot fluid outlet pipe 11 via another transition joint 9, completing the discharge of the hot fluid.

[0033] Preferably, in this embodiment, tube 7 is a knurled tube with a knurled structure on its outer surface, which can significantly enhance the heat exchange performance of the tube and improve the pre-cooling effect on the hot fluid.

[0034] In this embodiment, demister heat exchange blades 6 are provided on the lower part of the outer wall of the tube 7. The demister heat exchange blades 6 are corrugated aluminum sheets with 2 to 5 bends, each bend angle being 90° to 120°, forming a baffle structure similar to a blade separator. Vertically downward extending sealing plates 12 are provided at both ends of the demister heat exchange blades 6. The sealing plates 12 and the corrugated aluminum sheets in the demister heat exchange blades 6 together form a gas collecting groove. This gas collecting groove covers the entire upper surface of the plate-fin heat exchanger 2, and the lower end of the sealing plate 12 extends below the low operating liquid level, using liquid to achieve liquid sealing.

[0035] Preferably, in this embodiment, the corrugated aluminum fins are flanged and fixedly connected to the tube 7 via interference fit. The corrugated aluminum fins at the bottom of the tube 7 completely cover the outlet of the plate-fin heat exchanger 2, ensuring that the gas-liquid two-phase mixture flowing out of the heat exchanger siphon outlet is completely guided into the gas collection tank, preventing fluid deviation. Figure 3 As shown, each fold of the corrugated aluminum sheet has an extension section, which forms the liquid collection tank 13. The liquid collection tank 13 is used to collect the liquid separated by the corrugated aluminum sheet and discharge it to both sides of the heat exchanger, that is, the area outside the upper surface of the heat exchanger, to prevent the liquid from being re-entrained by the rising gas, thereby improving the separation efficiency.

[0036] In the device provided in this embodiment, a plurality of refrigerant inlet pipes 3 are provided at the bottom of the cylinder 1, and the refrigerant inlet pipes 3 are connected to the inner cavity of the cylinder 1; a plurality of refrigerant gas phase outlet pipes 5 are provided at the top of the cylinder 1.

[0037] Preferably, in this embodiment, the diameter of the refrigerant inlet pipe 3 is less than half the width of the plate-fin heat exchanger 2, so as to avoid the separation space being squeezed due to an excessively large inlet pipe diameter, which is conducive to maintaining a high gas-liquid separation efficiency in a compact structure. In order to facilitate equipment installation, maintenance and repair, a manhole inspection port 4 is also provided on the side wall of the cylinder 1 in this embodiment for easy equipment maintenance.

[0038] Next, this embodiment also provides a heat exchange method for the above-mentioned container-embedded plate-fin heat exchanger, as detailed below:

[0039] The hot fluid (such as ethylene) enters the shell 1 through the hot fluid inlet pipe 10, and then enters the internal core of the plate-fin heat exchanger 2 through the transition joint 9, the main pipe 8, and the tube 7 in sequence for heat exchange; after heat exchange, the hot fluid leaves the shell 1 through the transition joint 9 and the hot fluid outlet pipe 11.

[0040] Refrigerant (such as propylene) enters the shell 1 through the refrigerant inlet pipe 3 at the bottom of the shell 1, and exchanges heat with the hot fluid in the core of the plate-fin heat exchanger 2. After heat exchange, the refrigerant absorbs heat and evaporates into gas. The gas-liquid mixture is flushed out from the siphon outlet of the plate-fin heat exchanger 2 and enters the gas collection tank composed of the sealing plate 12 and corrugated aluminum fins. The gas-liquid mixture flows in the multiple bends of the corrugated aluminum fins. The liquid is captured by the corrugated surface due to inertial impact and gravity, and flows along the corrugations to the liquid collection tank 13, and is finally discharged to both sides of the heat exchanger. The separated gas continues to rise, and after further separation on the outer wall of the tube 7, it is discharged from the refrigerant gas phase outlet pipe 5.

[0041] With the above structure, the present invention achieves efficient gas-liquid separation in a compact container space, effectively avoiding mist entrainment and fluid deviation, and is especially suitable for complex working conditions such as large temperature difference and low refrigerant density.

[0042] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.

Claims

1. A compact, high-efficiency, container-integrated plate-fin heat exchanger, characterized in that, It includes a shell (1) and a plate-fin heat exchanger (2), demister heat exchange blades (6), tubes (7), main tube (8) and transition joint (9) installed in the shell (1); The side wall of the cylinder (1) is provided with a hot fluid inlet pipe (10) and a hot fluid outlet pipe (11), and the hot fluid inlet pipe (10) is higher than the hot fluid outlet pipe (11); one end of the hot fluid inlet pipe (10) is connected to the steel pipe side of the transition joint (9), and the aluminum pipe side of the transition joint (9) is connected to one end of the main pipe (8); the other end of the main pipe (8) is connected to several tubes (7); the lower end of the tubes (7) is connected to the end cap of the plate-fin heat exchanger (2) through an elbow, so as to introduce the hot fluid into the plate-fin heat exchanger (2); the outlet pipe of the plate-fin heat exchanger (2) passes through another The transition joint (9) is connected to the hot fluid outlet pipe (11); the lower part of the outer wall of the tube (7) is provided with demister heat exchange blades (6), and the two ends of the demister heat exchange blades (6) are respectively provided with vertically downward extending sealing plates (12); the sealing plates (12) and the demister heat exchange blades (6) form a gas collection groove for capturing the gas-liquid mixture from the outlet of the lower plate-fin heat exchanger (2); the bottom of the cylinder (1) is provided with several refrigerant inlet pipes (3), and the refrigerant inlet pipes (3) are connected to the inner cavity of the cylinder (1); the top of the cylinder (1) is provided with several connected refrigerant gas phase outlet pipes (5).

2. The compact, high-efficiency separation container-embedded plate-fin heat exchanger according to claim 1, characterized in that, The transition joint (9) is a steel-aluminum transition joint, and the main tube (8) and the column tube (7) are both aluminum tubes.

3. The compact, high-efficiency separation container-embedded plate-fin heat exchanger according to claim 1, characterized in that, The tubes (7) are made of knurled tubes to enhance heat exchange performance.

4. The compact, high-efficiency, separated container-embedded plate-fin heat exchanger according to claim 1, characterized in that, The defoaming heat exchange blades (6) are corrugated aluminum sheets with 2 to 5 bends, each bend angle being 90° to 120°.

5. The compact, high-efficiency separation container-embedded plate-fin heat exchanger according to claim 4, characterized in that, The corrugated aluminum sheet is flanged and fixedly connected to the tube (7) by interference fit; the corrugated aluminum sheet at the bottom of the tube (7) covers the outlet of the plate-fin heat exchanger (2).

6. The compact, high-efficiency separation container-embedded plate-fin heat exchanger according to claim 4, characterized in that, Each fold of the corrugated aluminum sheet is machined with an extension to form a liquid collection tank (13).

7. The compact, high-efficiency, container-embedded plate-fin heat exchanger according to claim 1, characterized in that, The sealing plate (12) extends downward below the low operating liquid level to achieve liquid sealing.

8. The compact, high-efficiency, separated container-embedded plate-fin heat exchanger according to claim 1, characterized in that, The diameter of the refrigerant inlet pipe (3) is less than 1 / 2 of the width of the plate-fin heat exchanger (2).

9. The compact, high-efficiency, separated container-embedded plate-fin heat exchanger according to claim 1, characterized in that, The side wall of the cylinder (1) is also provided with a manhole inspection port (4) to facilitate equipment maintenance.

10. A heat exchange method using a container-embedded plate-fin heat exchanger as described in any one of claims 1 to 9, characterized in that, Specifically as follows: The hot fluid enters the shell (1) through the hot fluid inlet pipe (10), passes through the transition joint (9), the main pipe (8), and the tube (7) in sequence, and then enters the internal core of the plate-fin heat exchanger (2) for heat exchange; the hot fluid after heat exchange leaves the shell (1) through the transition joint (9) and the hot fluid outlet pipe (11). The refrigerant enters the cylinder (1) from the refrigerant inlet pipe (3) at the bottom of the cylinder (1) and exchanges heat with the hot fluid in the core of the plate-fin heat exchanger (2). After the heat exchange, the heat-absorbing part of the refrigerant evaporates and becomes a gas-liquid two-phase fluid. After being heated by the defoaming heat exchange blades (6) and the tubes (7), it leaves the cylinder (1) from the refrigerant gas phase outlet pipe (5).

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