Heat exchanger core structure, spiral wound heat exchanger and EO / EG device

Abstract

The core structure of the heat exchanger, the wound tube heat exchanger and the EO / EG device, the core structure includes: a central tube; a heat exchange tube, having a spiral section, a straight tube section and a connecting section, and the outer diameter of the heat exchange tube is recorded as R; the connecting section has: a first arc section arched outward relative to the side wall of the central tube, the first end of the first arc section smoothly connects with the end of the spiral section, and the bending radius of the first arc section is recorded as R1, satisfying: 10R<R1<30R; a second arc section arched inward toward the side wall of the central tube, the first end of the second arc section smoothly connects with the end of the corresponding straight tube section, the second end of the second arc section smoothly connects with the second end of the first arc section, and the bending radius of the second arc section is recorded as R2, satisfying: 10R<R2<30R. The utility model can prevent the tube-side medium from forming vortices in the heat exchange tube.

Description

Technical Field

[0001] The utility model belongs to the technical field of heat exchangers, and in particular relates to a core structure of a heat exchanger, a wound tube heat exchanger and an EO / EG device. Background Art

[0002] The existing wound tube heat exchanger usually includes a shell and a core structure arranged in the shell. The core structure generally has a central tube, tube sheets arranged at both ends of the central tube, and a heat exchange tube spirally wound around the outer periphery of the central tube. The heat exchange tube wound around the outer periphery of the central tube mostly includes a central spiral section (also called a uniform section) and straight tube sections located on both sides of the central spiral section axially (the two straight tube sections can also be called a winding section and a closing section), and the ends of the two straight tube sections are supported on the corresponding tube sheets respectively. Specific structures such as the Chinese utility model patent "A heat exchange tube and a wound tube heat exchanger having the heat exchange tube" with patent number 202122266427.4 and authorization announcement number CN216159693U, and the Chinese utility model patent "A wound tube heat exchanger with high heat exchange efficiency" with patent number 201420757685.X and authorization announcement number CN204388658U.

[0003] The structure of the central spiral section and the straight section of the heat exchange tube often causes stress concentration problems at the junction of the two sections due to bending, which in turn causes damage to the heat exchange tube. In addition, during use, the structure of the junction of the existing central spiral section and the straight section may cause the tube-side medium to form vortices in the heat exchange tube.

[0004] In addition, the ethylene oxide / ethylene glycol (EO / EG) related technologies mainly include ethylene oxidation, that is, using ethylene and oxygen as raw materials, an oxidation reaction generates ethylene oxide (EO), and ethylene oxide (EO) is converted into ethylene glycol (EG) through a traditional hydration process or a catalytic hydrolysis process.

[0005] Existing devices for preparing EO / EG mostly include a reactor, an EO absorption tower, and a shell-and-tube heat exchanger. The shell-and-tube heat exchanger is used to exchange heat between the reaction product output from the reactor and the reaction feed (i.e., raw materials) to increase the temperature of the reaction feed and reduce the temperature of the reaction product. However, the shell-and-tube heat exchanger in the EO / EG device has problems such as large equipment diameter (the diameter of the tube sheet and the tube box is consistent with the diameter of the cylinder), high equipment height, large leakage flow, serious deviation flow, and uneven flow velocity distribution under the same cross section. In addition, since the reaction product contains inflammable and explosive media such as O2, EO, and ethylene, if the reaction product forms a vortex in the heat exchanger, severe vortex will generate static electricity and cause an explosion. Utility Model Content

[0006] The first technical problem to be solved by the utility model is to provide a core structure of a heat exchanger in view of the current status of the prior art, so as to prevent the tube-side medium from forming eddy currents in the heat exchange tubes.

[0007] The second technical problem to be solved by the utility model is to provide a wound tube heat exchanger with the core structure mentioned above.

[0008] The third technical problem to be solved by the present invention is to provide an EO / EG device having the above-mentioned wound tube heat exchanger so as to produce EO / EG safely and efficiently.

[0009] The technical solution adopted by the utility model to solve the above-mentioned first technical problem is: a core structure of a heat exchanger, comprising:

[0010] A central tube, with a first tube sheet and a second tube sheet respectively disposed at both ends;

[0011] The heat exchange tube comprises a spiral section spirally wound around the outer periphery of the central tube along the axial direction of the central tube, straight tube sections located on both sides of the spiral section axially, and a connecting section connecting the corresponding spiral section and the straight tube section, and the outer diameter of the heat exchange tube is denoted as R; the ends of the straight tube sections on both sides are supported on the first tube sheet and the second tube sheet respectively;

[0012] It is characterized in that the connecting section has:

[0013] A first arc segment arched outwardly relative to the side wall of the central tube, a first end of the first arc segment smoothly connects with the end of the spiral segment, and the bending radius of the first arc segment is R1, which satisfies: 10R<R1<30R;

[0014] A second arc segment arches inwardly toward the side wall of the center tube, and the first end of the second arc segment is smoothly connected with the end of the corresponding straight pipe segment, and the second end of the second arc segment is smoothly connected with the second end of the first arc segment, and the bending radius of the second arc segment is R2, satisfying: 10R<R2<30R.

[0015] In the utility model, the connecting section is designed to have a structure with a first arc section and a second arc section, and the bending radii of the first arc section and the second arc section are both greater than 10R and less than 30R, so that the transition between the straight pipe section and the spiral section is smoother, and the tube medium is prevented from forming eddy currents in the heat exchange tube. At the same time, the heat exchange tube can be prevented from being damaged due to stress concentration.

[0016] Preferably, the end of the spiral segment extends obliquely toward the first arc segment, and the connecting segment also has a third arc segment, which smoothly connects the end of the spiral segment with the first end of the first arc segment, and the bending radius of the third arc segment is R3, satisfying: 10R<R3<30R.

[0017] Preferably, R3>R2>R1.

[0018] Furthermore, the first arc segment, the second arc segment and the third arc segment are all inferior arcs smaller than a semicircle; and the arc length of the third arc segment>the arc length of the first arc segment>the arc length of the second arc segment.

[0019] In the above schemes, preferably, there are multiple heat exchange tubes, the straight tube sections of each heat exchange tube form a cylindrical body, and the outer diameter of the cylindrical body is recorded as D1, and the spiral sections of each heat exchange tube form a columnar body, and the outer diameter of the columnar body is recorded as D2, and both satisfy D2 / D1=1~2.5.

[0020] The technical solution adopted by the utility model to solve the second technical problem is: a wound tube heat exchanger, including a shell and a core structure arranged in the shell, wherein the shell further includes:

[0021] The shell side cylinder has a shell side inlet pipe and a shell side outlet pipe on its side wall;

[0022] The first pipe box and the second pipe box are respectively arranged at the two ends of the shell-side cylinder, and are respectively arranged corresponding to the first tube sheet and the second tube sheet in the core structure, and the first pipe box is provided with a tube-side inlet pipe, and the second pipe box is provided with a tube-side outlet pipe;

[0023] It is characterized in that the core structure adopts the core structure as described above, the central tube is arranged in the shell cylinder, and the ends of the two straight tube sections of the heat exchange tube are connected to the corresponding first tube box and second tube box.

[0024] The technical solution adopted by the utility model to solve the third technical problem mentioned above is: an EO / EG device, comprising: a reactor and an EO absorption tower, characterized in that it also includes the wound tube heat exchanger as described above, the tube side inlet pipe is connected to the discharge port of the reactor, the tube side outlet pipe is connected to the feed port of the EO absorption tower, the shell side inlet pipe is connected to a feed pipeline for conveying oxygen and ethylene, and the shell side outlet pipe is connected to the feed port of the reactor.

[0025] The reaction product output from the discharge port of the reactor goes through the tube side of the wound tube heat exchanger, and the reaction feed with oxygen and ethylene output from the feed pipeline goes through the shell side of the wound tube heat exchanger. The reaction feed in the shell side contacts the tube wall of each heat exchange tube, reducing the risk of leakage and bias flow, and the reaction feed is evenly distributed under the same cross section, ensuring heat exchange efficiency. At the same time, the structure of the heat exchange tube of the utility model can avoid the generation of eddy currents in the tube and improve safety.

[0026] Preferably, a water cooler is provided on the pipeline between the pipe outlet pipe and the feed inlet of the EO absorption tower.

[0027] Preferably, the top outlet of the EO absorption tower (9) is connected to the feed pipeline through a circulation pipeline, and a compressor and a heater are provided on the circulation pipeline.

[0028] Furthermore, it also includes a steam generator that can use the reaction heat in the reactor to heat water to generate steam. The steam generator has a hot water inlet for external hot water input, a steam outlet for steam output, and a heat inlet and a cold outlet connected to the reactor.

[0029] Compared with the prior art, the advantages of the present invention are as follows: in the present invention, the connecting section is designed to have a structure with a first arc section and a second arc section, and the bending radii of the first arc section and the second arc section are both greater than 10R and less than 30R, so that the transition between the straight pipe section and the spiral section is smoother, thereby avoiding the formation of vortexes in the heat exchange tube by the tube-side medium, and at the same time, avoiding damage to the heat exchange tube due to stress concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structure of some heat exchange tubes in an embodiment of the utility model;

[0031] Figure 2 It is a structural schematic diagram of part of the heat exchange tubes of an embodiment of the utility model from another perspective;

[0032] Figure 3 It is a schematic diagram of the partial structure of the heat exchange tube of an embodiment of the utility model;

[0033] Figure 4 This is a schematic structural diagram of a wound tube heat exchanger according to an embodiment of the utility model;

[0034] Figure 5 It is a schematic structural diagram of an EO / EG device according to an embodiment of the present utility model. DETAILED DESCRIPTION

[0035] The present invention will be described in further detail below in conjunction with the accompanying drawings.

[0036] like Figures 1 to 5 As shown, a preferred embodiment of the core structure of the heat exchanger, the wound tube heat exchanger and the EO / EG device of the utility model is shown, and the core structure includes a central tube 730, a first tube sheet 140 arranged at both ends of the central tube 730, a second tube sheet 160 and a plurality of heat exchange tubes 200, and the outer diameter of a single heat exchange tube 200 is recorded as R.

[0037] Each heat exchange tube 200 has a spiral section 20a spirally wound around the outer periphery of the central tube 730 along the axial direction of the central tube 730, straight tube sections 20b located on both sides of the spiral section 20a in the axial direction, and a connecting section 20c connecting the corresponding spiral section 20a and the straight tube section 20b. The ends of the straight tube sections 20b on both sides are supported on the first tube sheet 140 and the second tube sheet 160 respectively. The straight tube sections 20b of each heat exchange tube 200 are surrounded by a cylindrical body, and the outer diameter of the cylindrical body is recorded as D1. The spiral section 20a of each heat exchange tube 200 forms a columnar body, and the outer diameter of the columnar body is recorded as D2. Both satisfy D2 / D1=1~2.5 (D2 / D1 can be any value between 1 and 2.5, such as 1, 1.5, 2, 2.5, etc.). At the same time, the connecting section 20c of the present embodiment has a third arc segment 203, a first arc segment 201 and a second arc segment 202 which are connected in sequence. The first arc segment 201 is arched outward relative to the side wall of the central tube 730 and is relatively close to the straight tube segment 20b of the heat exchange tube 200, and the first end of the first arc segment 201 is smoothly connected with the end of the spiral segment 20a through the third arc segment 203; the second arc segment 202 is arched inward toward the side wall of the central tube 730 and is located on the inner side of the first arc segment 201, and the first end of the second arc segment 202 is smoothly connected with the end of the corresponding straight tube segment 20b, and the second end of the second arc segment 202 is smoothly connected with the second end of the first arc segment 201 through an inclined straight tube. In this embodiment, the first arc segment 201, the second arc segment 202 and the third arc segment 203 are all inferior arcs smaller than a semicircle; the arc length of the third arc segment 203> the arc length of the first arc segment 201> the arc length of the second arc segment 202. In addition, the bending radius of the first arc segment 201 is R1, the bending radius of the second arc segment 202 is R2, and the bending radius of the third arc segment 203 is R3, and the three satisfy: 30R>R3>R2>R1>10R. The connecting section 20c of this embodiment can be formed by bending the spirally wound heat exchange tube three times, so that the transition between the straight tube section 20b and the spiral section 20a is smoother, avoiding the formation of vortex in the heat exchange tube by the tube medium.

[0038] like Figure 4As shown, the wound tube heat exchanger 1 of this embodiment includes a shell-side cylinder 150, a first tube box 141, a second tube box 161 and the above-mentioned core structure. The shell-side cylinder 150 is arranged vertically, and a shell-side inlet pipe 170 is provided at the lower part of its side wall, and a shell-side outlet pipe 180 is provided at the upper part of its side wall. The above-mentioned first tube sheet 140 and the second tube sheet 160 are respectively arranged at the upper and lower ends of the shell-side cylinder 150. The above-mentioned first tube box 141 and the second tube box 161 are respectively arranged corresponding to the first tube sheet 140 and the second tube sheet 160, and the first tube box 141 is provided with a tube-side inlet pipe 110, and the second tube box 161 is provided with a tube-side outlet pipe 120; the above-mentioned central tube 730 is arranged in the shell-side cylinder 150, and the ends of the two straight tube sections 20b of the heat exchange tube 200 are connected to the corresponding first tube box 141 and the second tube box 161.

[0039] like Figure 5 As shown, the EO / EG device of this embodiment includes a reactor 8, an EO absorption tower 9, the above-mentioned wound tube heat exchanger 1 and a steam generator 6. The steam generator 6 can use the reaction heat in the reactor 8 to heat water to generate steam, and has a hot water inlet 61 for external hot water input, a steam outlet 62 for steam output, and a heat inlet 63 and a cold outlet 64 connected to the reactor 8.

[0040] The tube side inlet pipe 110 of the wound tube heat exchanger 1 is connected to the discharge port of the reactor 8. The tube side outlet pipe 120 of the wound tube heat exchanger 1 is connected to the feed port of the EO absorption tower 9 through a pipeline, and a water cooler 7 is provided on the pipeline. The shell side inlet pipe 170 of the wound tube heat exchanger 1 is connected to a feed pipeline 171 for conveying oxygen and ethylene, and the shell side outlet pipe 180 is connected to the feed port of the reactor 8. The top outlet of the EO absorption tower 9 is connected to the feed pipeline 171 through a circulation pipeline 172, and a compressor 173 and a heater 174 are provided on the circulation pipeline 172.

[0041] The steps of preparing EO / EG using the EO / EG device of this embodiment are as follows:

[0042] The reaction feed containing oxygen and ethylene and having a temperature of 63°C in the feed pipeline 171 is used as a shell-side medium and is input into the shell side of the wound tube heat exchanger 1 through the shell-side inlet pipe 170; the temperature of the reaction feed outputted from the shell-side outlet pipe 180 is 208°C, and is inputted into the reactor 8 for reaction and then outputted, and the temperature of the output EO reaction product is 227°C, and the EO reaction product is used as a tube-side medium and is inputted into the tube side of the wound tube heat exchanger 1 through the tube-side inlet pipe 110 to exchange heat with the shell-side medium, and the temperature of the EO reaction product outputted from the tube-side outlet pipe 120 is 82°C and is transported to the EO absorption tower 9, and the material outputted from the bottom of the EO absorption tower 9 is transported to the downstream equipment to generate EG.

Claims

1. A core structure of a heat exchanger, comprising: A central tube (730) having a first tube sheet (140) and a second tube sheet (160) respectively disposed at two ends thereof; The heat exchange tube (200) comprises a spiral section (20a) spirally wound around the outer periphery of the central tube (730) along the axial direction of the central tube (730), straight tube sections (20b) located on both axial sides of the spiral section (20a), and a connecting section (20c) connecting the corresponding spiral sections (20a) and straight tube sections (20b), and the outer diameter of the heat exchange tube (200) is denoted as R; the ends of the straight tube sections (20b) on both sides are supported on the first tube sheet (140) and the second tube sheet (160) respectively; Features The connecting section (20c) has: A first arc segment (201) arched outwardly relative to the side wall of the central tube (730), a first end of the first arc segment (201) smoothly connected with the end of the spiral segment (20a), and the bending radius of the first arc segment (201) is R1, satisfying: 10R<R1<30R; A second arc segment (202) is arched inwardly toward the side wall of the center tube (730), and the first end of the second arc segment (202) is smoothly connected with the end of the corresponding straight tube segment (20b), and the second end of the second arc segment (202) is smoothly connected with the second end of the first arc segment (201), and the bending radius of the second arc segment (202) is R2, which satisfies: 10R<R2<30R.

2. The core structure according to claim 1, characterized in that: The end of the spiral segment (20a) extends obliquely toward the first arc segment (201), and the connecting segment (20c) further comprises a third arc segment (203) which smoothly connects the end of the spiral segment (20a) and the first end of the first arc segment (201), and the bending radius of the third arc segment (203) is R3, satisfying the following: 10R<R3<30R.

3. The core structure according to claim 2, characterized in that: R3>R2>R1.

4. The core structure according to claim 3, characterized in that: The first circular arc segment (201), the second circular arc segment (202) and the third circular arc segment (203) are all minor arcs smaller than a semicircle; and the arc length of the third circular arc segment (203) is greater than the arc length of the first circular arc segment (201) and greater than the arc length of the second circular arc segment (202).

5. The core structure according to any one of claims 1 to 4, characterized in that: There are multiple heat exchange tubes (200), and the straight tube sections (20b) of each heat exchange tube (200) are enclosed in a cylindrical body, and the outer diameter of the cylindrical body is recorded as D1. The spiral sections (20a) of each heat exchange tube (200) form a columnar body, and the outer diameter of the columnar body is recorded as D2, and both satisfy D2 / D1=1~2.

5.

6. A wound tube heat exchanger, comprising a shell and a core structure arranged in the shell, wherein the shell further comprises: A shell-side cylinder (150) has a shell-side inlet pipe (170) and a shell-side outlet pipe (180) provided on its side wall; The first pipe box (141) and the second pipe box (161) are respectively arranged at two ends of the shell-side cylinder (150), and are respectively arranged corresponding to the first tube sheet (140) and the second tube sheet (160) in the core structure, and the first pipe box (141) is provided with a tube-side inlet pipe (110), and the second pipe box (161) is provided with a tube-side outlet pipe (120); Features The core structure adopts the core structure as described in any one of claims 1 to 5, the central tube (730) is arranged in the shell-side cylinder (150), and the ends of the two straight tube sections (20b) of the heat exchange tube (200) are connected to the corresponding first tube box (141) and second tube box (161).

7. An EO / EG device, comprising: a reactor (8) and an EO absorption tower (9), characterized in that It also includes the wound tube heat exchanger as described in claim 6, wherein the tube side inlet pipe (110) is connected to the discharge port of the reactor (8), the tube side outlet pipe (120) is connected to the feed port of the EO absorption tower (9), the shell side inlet pipe (170) is connected to a feed pipeline (171) for conveying oxygen and ethylene, and the shell side outlet pipe (180) is connected to the feed port of the reactor (8).

8. The EO / EG device according to claim 7, characterized in that: A water cooler (7) is provided on the pipeline between the pipe outlet pipe (120) and the feed inlet of the EO absorption tower (9).

9. The EO / EG device according to claim 7, characterized in that: The top outlet of the EO absorption tower (9) is connected to the feed pipeline (171) through a circulation pipeline (172), and a compressor (173) and a heater (174) are provided on the circulation pipeline (172).

10. The EO / EG device according to claim 7, characterized in that: The invention also includes a steam generator (6) which can utilize the reaction heat in the reactor (8) to heat water to generate steam. The steam generator (6) has a hot water inlet (61) for inputting external hot water, a steam outlet (62) for outputting steam, and a heat inlet (63) and a cold outlet (64) connected to the reactor (8).

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