Winding pipe type heat exchanger

Abstract

A winding tube type heat exchanger is vertically arranged, a shell pass and a tube pass are arranged in the winding tube type heat exchanger, a heat exchange tube forming the tube pass is spirally wound around the periphery of a center cylinder in the vertical direction, and the tube pass is provided with a tube pass inlet for cold medium input and a tube pass outlet for cold medium output after heat exchange; the upper part of the shell side is provided with a shell side inlet for inputting a medium to be condensed, and the lower part of the shell side is provided with a cavity for receiving condensate and a shell side liquid phase outlet for outputting the condensate in the cavity; meanwhile, the upper portion of the shell pass is provided with a shell pass gas phase outlet for outputting non-condensable gas, the interior of the center cylinder is hollow to form an independent channel extending vertically, a lower port of the independent channel is located above the cavity so that the non-condensable gas can pass upwards and enter the independent channel, and an upper port of the independent channel is communicated with the shell pass gas phase outlet. The condenser can be used for condensing media such as overhead gas and the like, and the number of downstream equipment can be reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of heat exchangers, and in particular relates to a wound tube heat exchanger. Background Art

[0002] Conventional vacuum tower top gas temperature is low, heat recovery is difficult, the tower top gas is directly cooled by air cooling and / or water cooling, the condensed liquid phase enters a separate storage tank, the top of the storage tank is equipped with non-condensable gas condensation recovery and vacuum connection, please refer to the details Figure 1 In the prior art, the tower top condensation, the separation of the non-condensable gas after condensation, and the vacuum pumping system are complicated, and the resistance drop is large, making it difficult to ensure the vacuum degree of the vacuum tower top pressure or the energy consumption is high. And because of the above problems, the vacuum degree of the vacuum tower is reduced, the operating temperature of the vacuum tower is high, the vacuum tower feed needs to be directly heated by a heat source, and the temperature of the heat source is high, and the energy consumption of the vacuum tower operation is high.

[0003] At the same time, the existing air-cooled and / or water-cooled condensers, storage tanks, pumps, condensers above the storage tanks and other equipment used for cooling the tower top gas are numerous, occupy a large area, and have high operating and maintenance costs. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a wound tube heat exchanger which can be used for condensing the medium waiting for condensation of the tower top gas in view of the current status of the prior art, so as to reduce the number of downstream equipment.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: a wound tube heat exchanger, which is vertically arranged and has a shell side and a tube side inside, the heat exchange tubes forming the tube side are vertically spirally wound around the outer periphery of the central tube, and the tube side has a tube side inlet for inputting a cooling medium and a tube side outlet for outputting the cooling medium after heat exchange;

[0006] Features:

[0007] The upper part of the shell side has a shell side inlet for inputting the medium to be condensed, the lower part of the shell side has a chamber for receiving the condensate, and has a shell side liquid phase outlet for outputting the condensate in the chamber; at the same time, the upper part of the shell side has a shell side gas phase outlet for outputting the non-condensable gas, and the central tube is hollow inside to form a vertically extending independent channel, the lower port of the independent channel is located above the chamber to allow the non-condensable gas to pass upward and enter the independent channel, and the upper port of the independent channel is connected to the shell side gas phase outlet.

[0008] The medium to be condensed enters the shell side through the shell side inlet, flows downward, and exchanges heat with the cold medium in the tube side. After condensation, the condensate flows into the chamber under its own gravity, and then is discharged from the shell side liquid phase outlet. The non-condensable gas enters the independent channel inside the central tube from the lower port of the central tube, and then flows upward and is discharged from the shell side gas phase outlet. In this process, the chamber acts as a "storage tank" without the need to set up an additional storage tank. There is no need to set up additional equipment such as a condenser above the storage tank. Therefore, the design of the wound tube heat exchanger of the present invention can simplify downstream equipment.

[0009] Preferably, the shell-side gas phase outlet is located at the top of the shell-side, and the upper end of the central tube extends upward to the shell-side gas phase outlet, thereby simplifying the structure.

[0010] Also preferably, the shell-side gas phase outlet is located at the side of the shell-side, and the upper end of the central tube is connected to the shell-side gas phase outlet through an intermediate pipeline.

[0011] Furthermore, the shell side is provided with:

[0012] An upper distribution plate and a lower distribution plate, the plate surfaces of which are opposite to each other and arranged above the central tube, and the edges of the two plates are butted against the shell side wall so that the above-mentioned intermediate pipeline is formed between the two plates and the shell side wall, and a through hole is provided in the center of the lower distribution plate to connect the intermediate pipeline with the independent channel;

[0013] A connecting pipe with a hollow interior and heat-conducting wall is vertically inserted in the upper distribution plate and the lower distribution plate, and the upper end of the connecting pipe opens in the upper distribution plate, and the lower end of the connecting pipe opens in the lower distribution plate and is located at the periphery of the through hole;

[0014] The shell side inlet is located above the upper distribution plate.

[0015] In this way, the medium to be condensed entering from the shell side inlet passes through the connecting pipe and enters the space below the lower distribution plate to exchange heat with the cold medium in the tube side. Before heat exchange, the medium to be condensed in the connecting pipe can preheat the non-condensable gas in the intermediate pipeline to prevent the non-condensable gas from carrying the uncondensed gas phase from the shell side gas phase outlet to enter the downstream vacuum pump to produce droplets and damage the equipment.

[0016] In order to ensure the preheating effect of the non-condensable gas, preferably, there are multiple connecting pipes, which are arranged at intervals on the upper and lower distribution plates. And the design of multiple connecting pipes can achieve uniform flow of the medium to be condensed, so that the medium to be condensed can evenly enter the space below the lower distribution plate and exchange heat with the tube-side medium in the heat exchange tube, thereby ensuring the heat exchange effect.

[0017] Furthermore, an annular tube with a hollow interior forming the intermediate pipeline is provided in the shell side. The annular tube is circumferentially arranged at the periphery of the upper end of the central tube and is connected with the central tube and the shell side gas phase outlet.

[0018] In the above schemes, preferably, a plurality of fins are vertically spaced in the central tube, and each fin extends obliquely upward from the inner wall of the central tube. The fins can improve the deliquescence effect on the non-condensable gas and enhance the bending strength of the central tube.

[0019] Preferably, a leakage hole is provided at the connection between the fin and the inner wall of the central tube, so that the condensate can pass through and enter the chamber.

[0020] Preferably, the fins are arranged relatively close to the lower end of the central tube.

[0021] In the above schemes, preferably, the wall of the central tube is a heat-conducting wall. Since a heat exchange tube is arranged around the outer circumference of the central tube, the coldness of the cold medium in the heat exchange tube can be transferred to the central tube through the wall of the central tube, so that the non-condensable gas in the central tube can be further condensed, thereby improving the deliquescence effect of the non-condensable gas.

[0022] Compared with the prior art, the advantages of the present invention are: by designing the positions of the shell side inlet and the shell side gas phase outlet, and setting a chamber in the shell side and a central tube with an independent channel extending vertically formed in the hollow interior, during heat exchange, the medium to be condensed enters the shell side through the shell side inlet and flows downward, and after heat exchange and condensation with the cold medium in the tube side, the condensate flows into the chamber under the action of its own gravity, and then is output from the shell side liquid phase outlet, and the non-condensable gas enters the independent channel inside the central tube from the lower port of the central tube, and then flows upward and is discharged from the shell side gas phase outlet. In this process, the chamber acts as a "storage tank" without the need to set up an additional storage tank. There is also no need to set up equipment such as a condenser above the storage tank. Therefore, the design of the wound tube heat exchanger of the present invention can simplify downstream equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of a vacuum tower top condensation reflux system in the prior art;

[0024] Figure 2 This is a schematic structural diagram of a vacuum tower top condensation reflux system according to Embodiment 1 of the present invention;

[0025] Figure 3 A longitudinal cross-sectional view of a wound tube heat exchanger according to Embodiment 1 of the present invention;

[0026] Figure 4 for Figure 3 Enlarged view of part A in the middle;

[0027] Figure 5 for Figure 4 Top view of the middle fin;

[0028] Figure 6 for Figure 4 Schematic diagram of the middle fin in direction B;

[0029] Figure 7 It is a longitudinal cross-sectional view of a wound tube heat exchanger according to the second embodiment of the present invention;

[0030] Figure 8 It is a longitudinal cross-sectional view of a wound tube heat exchanger according to the third embodiment of the present invention. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below with reference to the accompanying drawings.

[0032] Embodiment 1:

[0033] like Figures 2 to 6 As shown, it is a preferred embodiment 1 of a wound tube heat exchanger of the invention, and the wound tube heat exchanger can be used for condensing the top gas of a vacuum tower. This embodiment is described in conjunction with a vacuum tower, and is specifically as follows:

[0034] The vacuum tower 1 is of prior art.

[0035] The wound tube heat exchanger 2 is vertically arranged above the vacuum tower 1, and has a shell side cylinder forming a shell side 22, a central cylinder 20 vertically arranged in the shell side cylinder, and a heat exchange tube vertically spirally wound around the outer periphery of the central cylinder 20. The heat exchange tube forms a tube side 21, and there are two tube sides 21, namely the first tube side 211 and the second tube side 212. The first tube side inlet 211a is used for raw material input, the first tube side outlet 211b is connected to the vacuum tower 1 through a pipeline, the second tube side inlet 212a is used for external cold source input, and the second tube side outlet 212b is used for cold source output after heat exchange. At the same time, a shell side inlet 22a for vacuum tower top gas input is provided at the top of the shell side cylinder, and the shell side inlet 22a is connected to the top outlet of the vacuum tower 1 through a pipeline. The bottom space of the shell-side cylinder is a chamber 220 for receiving the condensate after the condensation of the vacuum tower top gas. The chamber 220 is located below the central cylinder 20. The bottom of the chamber 220 is provided with a shell-side liquid phase outlet 22b for the output of the condensate. The shell-side liquid phase outlet 22b is connected to the vacuum tower 1 and the downstream equipment through two pipelines, and a valve for controlling the flow rate is provided on the pipeline connecting the shell-side liquid phase outlet 22b and the vacuum tower 1. At the same time, the center cylinder 20 is hollow inside to form an independent channel. The lower port of the independent channel is located above the chamber 220 to allow the non-condensable gas to pass upward. The upper port of the independent channel is connected to the shell-side gas phase outlet 22c on the upper side wall of the shell-side cylinder through the intermediate pipeline 26. The shell-side gas phase outlet 22c is used to be connected to the vacuum pump.

[0036] In this embodiment, an upper distribution plate 261, a lower distribution plate 262 and a plurality of connecting pipes 264 are provided in the shell-side cylinder. The upper distribution plate 261 and the lower distribution plate 26 are arranged above the center cylinder 20 with their plate surfaces facing each other, one above and one below the other. The edges of the two are butted against the side wall of the shell-side cylinder so that the above-mentioned intermediate pipeline 26 is formed between the two and the side wall of the shell-side cylinder. A through hole 263 is provided in the center of the lower distribution plate 262 to connect the intermediate pipeline 26 with the independent channel in the center cylinder 20. The connecting pipe 264 is hollow inside and the tube wall can conduct heat. The connecting pipes 264 are arranged at intervals in the horizontal direction and vertically inserted in the upper distribution plate 261 and the lower distribution plate 262. The upper port of the connecting pipe 264 is located above the upper distribution plate 261, and the lower port of the connecting pipe 264 is located below the lower distribution plate 262 and is located on the periphery of the through hole 263, so that the vacuum tower top gas entering from the shell side inlet 22a can flow downward through the connecting pipe 264 to the space below the lower distribution plate 26 and exchange heat with the cold medium in the heat exchange tube for condensation. The condensate after heat exchange is collected in the chamber 220, and the non-condensable gas enters the central tube 20 from the lower port.

[0037] The non-condensable gas entering the central tube 20 may carry uncondensed gas phase. In order to further remove the liquid from the non-condensable gas entering the central tube 20, the tube wall of the central tube 20 is a heat-conducting wall that can conduct heat. A plurality of fins 201 are arranged vertically at intervals in the central tube 20. The fins 201 are arranged relatively close to the lower end of the central tube 20. Each fin 201 extends upwardly from the inner wall surface of the central tube 20, and a leakage hole 202 is arranged at the connection between each fin 201 and the inner wall surface of the central tube 20, so that the liquid can flow down and be collected in the chamber 220. The non-condensable gas passing through each fin 201 continues to flow upward into the intermediate pipeline 26. At this time, the vacuum tower top gas energy through the connecting pipe 264 can preheat the non-condensable gas in the intermediate pipeline 26 to prevent the non-condensable gas from carrying the uncondensed gas phase into the vacuum pump to generate droplets and damage the equipment. In this embodiment, since the fins 201 are arranged relatively close to the lower end of the central tube 20 , and the lower end of the central tube 20 is relatively close to the tube inlet, the cold medium with a lower temperature can condense and remove liquid from the non-condensable gas in the central tube 20 .

[0038] The wound tube heat exchanger of this embodiment replaces the original tower top condenser (air cooling + water cooling), storage tank, reflux pump and distillate pump, reducing equipment investment and achieving significant energy saving effect. The wound tube heat exchanger uses the central tube as the space for gas-liquid separation, which helps to reduce the size of the equipment and reduce the height of the equipment, thereby reducing the resistance loss, increasing the vacuum degree of the tower, and reducing the energy consumption of the vacuum pump.

[0039] Embodiment 2:

[0040] like Figure 7As shown, a preferred embodiment 2 of a vacuum tower top condensation reflux system of the present invention is shown. This embodiment is basically the same as the embodiment 1, except that in this embodiment, an annular tube with a hollow interior forming an intermediate pipeline 26 is provided in the shell-side cylinder. The annular tube is circumferentially arranged on the periphery of the upper end of the central cylinder 20, and is connected to the central cylinder 20 and the shell-side gas phase outlet 22c.

[0041] Embodiment three:

[0042] like Figure 8 As shown, a preferred embodiment 3 of a vacuum tower top condensation reflux system of the present invention is shown. This embodiment is basically the same as the embodiment 1, except that in this embodiment, the shell-side gas phase outlet 22c is located at the top of the shell-side cylinder, and the upper end of the central cylinder 20 extends upward and is directly connected to the shell-side gas phase outlet 22c.

[0043] In the specification and claims of the present invention, terms indicating directions, such as "upper", "lower", "side", "top", "bottom", etc., are used to describe various exemplary structural parts and elements of the present invention, but these terms are used here only for the purpose of convenience of description and are determined based on the exemplary orientations shown in the accompanying drawings. Since the embodiments disclosed in the present invention can be arranged in different directions, these terms indicating directions are only used as explanations and should not be regarded as limitations. For example, "upper" and "lower" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

[0044] The term "vertical" is also used in the specification and claims of the present invention, which means basically along the up and down direction, and is not limited to the vertical direction only, and can also be slightly inclined relative to the vertical direction.

Claims

1. A wound tube heat exchanger, which is arranged vertically and has a shell side (22) and a tube side (21) inside, wherein the heat exchange tubes forming the tube side (21) are vertically spirally wound around the outer circumference of a central tube (20), and the tube side (21) has a tube side inlet for inputting a cooling medium and a tube side outlet for outputting the cooling medium after heat exchange; Features: The upper part of the shell side (22) has a shell side inlet (22a) for inputting the medium to be condensed, the lower part of the shell side (22) has a chamber (220) for receiving the condensate, and has a shell side liquid phase outlet (22b) for outputting the condensate in the chamber (220); at the same time, the upper part of the shell side (22) has a shell side gas phase outlet (22c) for outputting the non-condensable gas, and the central tube (20) is hollow inside to form a vertically extending independent channel, the lower port of the independent channel is located above the chamber (220) to allow the non-condensable gas to pass upward and enter the independent channel, and the upper port of the independent channel is connected to the shell side gas phase outlet (22c).

2. The wound tube heat exchanger according to claim 1, characterized in that: The shell-side gas phase outlet (22c) is located at the top of the shell-side (22), and the upper end of the central tube (20) extends upward to the shell-side gas phase outlet (22c).

3. The wound tube heat exchanger according to claim 1, characterized in that: The shell-side gas phase outlet (22c) is located at the side of the shell-side (22), and the upper end of the central tube (20) is connected to the shell-side gas phase outlet (22c) through an intermediate pipeline (26).

4. The wound tube heat exchanger according to claim 3, characterized in that: The shell side (22) is provided with: An upper distribution plate (261) and a lower distribution plate (262), the plate surfaces of which are arranged above the central tube (20) and below each other, and the edges of which are butted against the side wall of the shell side (22) so that the intermediate pipeline (26) is formed between the upper distribution plate (261) and the lower distribution plate (262), and a through hole (263) is provided in the center of the lower distribution plate (262) to connect the intermediate pipeline (26) with the independent channel; A connecting tube (264) with a hollow interior and a heat-conducting tube wall is vertically inserted into the upper distribution plate (261) and the lower distribution plate (262), and the upper end of the connecting tube (264) opens to the upper distribution plate (261), and the lower end of the connecting tube (264) opens to the lower distribution plate (262) and is located at the periphery of the through hole (263); The shell side inlet (22a) is located above the upper distribution plate (261).

5. The wound tube heat exchanger according to claim 4, characterized in that: There are a plurality of connecting pipes (264) arranged at intervals on the upper and lower distribution plates.

6. The wound tube heat exchanger according to claim 3, characterized in that: The shell side (22) is provided with an annular tube with a hollow interior forming the intermediate pipeline (26). The annular tube is circumferentially arranged on the periphery of the upper end of the central tube (20) and is connected to the central tube (20) and the shell side gas phase outlet (22c).

7. The wound tube heat exchanger according to any one of claims 1 to 6, characterized in that: A plurality of fins (201) are arranged at intervals along the vertical direction in the central tube (20), and each fin (201) extends obliquely upward from the inner wall surface of the central tube (20).

8. The wound tube heat exchanger according to claim 7, characterized in that: A liquid leakage hole (202) is provided at the connection between the fin (201) and the inner wall surface of the central tube (20).

9. The wound tube heat exchanger according to claim 7, characterized in that: The fin (201) is arranged relatively close to the lower end of the central tube (20).

10. The wound tube heat exchanger according to any one of claims 1 to 6, characterized in that: The cylinder wall of the central cylinder (20) is a heat-conducting wall.

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