High-efficiency evaporator based on high-flux heat exchange

Abstract

The application provides a high-efficiency evaporator based on high-flux heat exchange, which comprises a left pipe box, a middle section and a right pipe box, heat exchange pipes are arranged in the middle section, the two ends of the heat exchange pipes are respectively welded with pipe plates, the middle part is a heat exchange section, the inner surface of the heat exchange section is densely covered with inner surface spiral ribs, and the outer surface is arranged with outer surface dimples, the inner surface structure is a continuous spiral groove, the outer surface is dimples, and the dimples are provided with a porous layer. The spiral groove on the inner surface increases the heat exchange area and improves the heat exchange efficiency, and has the effect of flow disturbance, so that the heat exchange medium is prevented from being scaled; the dimples on the outer surface increase the heat exchange area, the dimples outside the pipe increase a large amount of area, and the porous structure on the dimples can provide a large amount of vaporization cores, so that the evaporator has excellent heat transfer enhancement effect under the pipe outside evaporation working condition.

Description

Technical Field

[0001] This application relates to the field of heat transfer equipment technology, and in particular to a high-efficiency evaporator based on high-throughput heat exchange. Background Technology

[0002] With the continuous advancement of technology in industries such as petroleum, petrochemicals, and fine chemicals, the requirements for heat exchangers are also increasing accordingly. Traditional high-flux heat exchangers use two types of heat exchange tubes: one type has a porous inner layer and a smooth outer tube or is machined into special shapes, such as longitudinal grooves, fins, corrugations, or spiral patterns. This type of heat exchanger is used for in-tube evaporation, especially vertical heat exchangers with in-tube evaporation. The other type has a porous outer layer and a smooth inner tube or is machined into special shapes, such as straight grooves or spiral grooves. This type of heat exchanger is used for out-of-tube evaporation. Currently, double-sided reinforced high-flux tubes are widely used. One side of the base tube has a porous layer fabricated on top of a smooth tube, while the other side has a specially machined structure. This further improves heat transfer efficiency and reduces equipment investment compared to traditional high-flux heat exchangers.

[0003] Currently, most high-throughput heat exchangers on the market use an external longitudinal groove with an internal porous layer or a single external porous layer for their internal heat exchange tubes. The external porous layer is basically prepared on the basis of a smooth tube. A few are processed before the porous layer is prepared. The processing of corrugated tubes and spiral groove tubes reduces the specific surface area and has no effect on evaporation. The porous layer is prepared after processing into fins, which easily fills the gaps between the fins, thus eliminating the effect of increasing the area by processing the fins and making the evaporation effect of the heat exchange tubes not obvious. Summary of the Invention

[0004] This application provides a high-efficiency evaporator based on high-throughput heat exchange, which can be used to solve the technical problem of ineffective evaporation in evaporators.

[0005] This application provides a high-efficiency evaporator based on high-throughput heat exchange, characterized in that the high-efficiency evaporator includes a heat exchange tube bundle disposed in the middle, the heat exchange tube bundle including a plurality of heat exchange tubes; a left tube box is disposed on one side of the heat exchange tube bundle and a right tube box is disposed on the other side.

[0006] A liquid inlet is located at the top of the left tubing tank; a liquid outlet is located at the bottom of the right tubing tank.

[0007] The outer layer of the heat exchange tubes in the heat exchange tube bundle is a support plate; a gas outlet is set at the top of the heat exchange tube bundle and a liquid inlet is set at the bottom.

[0008] The edges at both ends of the heat exchange tube are smooth; the inner and outer surfaces of the heat exchange section in the middle of the heat exchange tube are processed with different structures, with the inner surface densely covered with inner surface spiral ribs and the outer surface covered with outer surface pitting.

[0009] Furthermore, the outer surface with pitted surface is covered with a porous outer surface layer.

[0010] Furthermore, the inner surface spiral ribs have a spiral angle of 30 to 41°, a height range of 0.2 to 0.3 mm, and a number of heads range of 20 to 30; the cross-section of the inner surface spiral ribs is triangular or trapezoidal.

[0011] Furthermore, the spacing of the pits on the outer surface ranges from 1.25 to 2.0 mm, and the height ranges from 0.3 to 0.4 mm;

[0012] The pitting on the outer surface includes circumferential grooves and longitudinal grooves, with a helical angle ranging from 0.9 to 1.9°.

[0013] Furthermore, the thickness of the porous layer on the outer surface ranges from 0.1 to 0.15 mm, and the porosity ranges from 40 to 60%.

[0014] Furthermore, the outer surface pitting and the inner surface spiral ribs are formed in one process.

[0015] This application has the following beneficial effects:

[0016] 1. Reduce initial investment in high-throughput heat exchangers: As heat exchange efficiency increases, the number of heat exchange tubes can be reduced accordingly, and the size of the shell and tube sheet can also be reduced, which can significantly reduce the cost of heat exchanger equipment.

[0017] 2. Reduce process energy consumption of high-throughput heat exchangers: With the improvement of heat exchange efficiency, the system loses less energy and has a higher utilization rate, which helps to save the operating costs of engineering projects;

[0018] 3. Reduce the installation space required for high-throughput heat exchangers: When upgrading or replacing processes in some projects, the installation space is limited. Only by selecting high-throughput heat exchangers with higher heat exchange efficiency can the project be successfully completed. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a high-throughput heat exchanger.

[0020] Figure 2 A longitudinal section and enlarged view of a high-throughput tube with an inner spiral and an outer roughened surface;

[0021] Figure 3 This is a cross-sectional view and enlarged view of a high-throughput tube with an inner spiral and an outer roughened surface.

[0022] Figure 1 In the middle: 1—Liquid inlet, 2—Left tube box, 3—Heat exchange tube, 4—Support plate, 5—Gas outlet, 6—Shell, 7—Right tube box, 8—Liquid outlet, 9—Liquid inlet.

[0023] Figure 2In the middle: 21—outer surface circumferential spiral groove, 22—inner surface spiral rib, 23—outer surface porous layer.

[0024] Figure 3 In the middle: 24—longitudinal groove on the outer surface, 25—pockmarks on the outer surface. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0026] The embodiments of this application will now be described in conjunction with the accompanying drawings.

[0027] This application provides a high-efficiency evaporator based on high-throughput heat exchange, including a heat exchange tube bundle disposed in the middle, the heat exchange tube bundle including a plurality of heat exchange tubes 3; a left tube box 2 is disposed on one side of the heat exchange tube bundle and a right tube box 7 is disposed on the other side.

[0028] A liquid inlet 1 is provided above the left tube box 2; a liquid outlet 8 is provided below the right tube box 7.

[0029] The outer layer of the heat exchange tube 3 in the heat exchange tube bundle is a support plate 4; a gas outlet 5 is provided above the heat exchange tube bundle and a liquid inlet 9 is provided below it.

[0030] The edges at both ends of the heat exchange tube 3 are smooth tubes; the inner and outer surfaces of the heat exchange section in the middle of the heat exchange tube 3 are processed with different structures, wherein the inner surface is densely covered with inner surface spiral ribs 22; and the outer surface is covered with outer surface pits 25.

[0031] The outer surface of the pitted surface 25 is covered with a porous outer surface layer 23.

[0032] The inner surface spiral rib 22 has a spiral angle of 30 to 41°, a height range of 0.2 to 0.3 mm, and a number of heads range of 20 to 30; the cross section of the inner surface spiral rib 22 is triangular or trapezoidal.

[0033] The spacing of the pits 25 on the outer surface ranges from 1.25 to 2.0 mm, and the height ranges from 0.3 to 0.4 mm.

[0034] The outer surface pitting 25 includes an circumferential groove 21 and a longitudinal groove 24, with a helical angle ranging from 0.9 to 1.9°.

[0035] The thickness of the porous layer 23 on the outer surface ranges from 0.1 to 0.15 mm, and the porosity ranges from 40 to 60%.

[0036] The outer surface pitting 25 and the inner surface spiral ribs 22 are formed in one process.

[0037] The heat exchange tubes can be made from any material such as carbon steel, stainless steel, nickel-based alloys, and copper alloys.

[0038] The external pitting and internal spiral groove structure of the heat exchange tube are formed in one go through a combination of various molds, so that the outer diameter of the heat exchange section is smaller than the outer diameter of the bare tubes at both ends, with the difference in outer diameter ranging from 0.2 to 0.3 mm. The heat exchange section then undergoes a subsequent porous layer preparation process, which increases the outer diameter by 0.2 to 0.3 mm, making the outer diameter the same as that of the bare tubes at both ends.

[0039] The inner surface of this application can effectively eliminate the laminar boundary layer formed by the fluid inside the pipe on the pipe wall, and the disturbance makes the heat transfer temperature field of the fluid inside the pipe more uniform, thereby improving the heat transfer coefficient inside the pipe; the pitted surface of its outer surface can increase the outer area of ​​the pipe by about 1.5 times, and the porous layer on the pits can provide a large number of vaporization nuclei, thereby improving the heat transfer coefficient outside the pipe. By simultaneously strengthening the inner and outer surfaces, the heat transfer efficiency of the high-flux heat exchanger is further improved.

[0040] The present invention will be further described below with reference to the accompanying drawings and specific examples.

[0041] Implementation Cases

[0042] Referring to the attached diagram, a novel high-throughput heat exchanger has an overall length of 8000 mm and a diameter of 2350 mm. The liquid medium enters the shell side from the liquid inlet 9 at the bottom of the shell 6. After boiling heat exchange, it changes from liquid to gas and exits from the gas outlet 5 at the top of the shell 6. The high-temperature liquid phase enters the tube side from the liquid inlet 1 of the left tube box 2. After heat exchange, the medium temperature decreases, becoming a low-temperature liquid phase, and exits from the liquid outlet 8 of the right tube box 7. The evaporator contains 1820 φ19*1.5*5000 mm carbon steel high-throughput tubes with an inner spiral and outer roughened surface. The roughened surface has a pitted gap of 1.5 mm and a height of 0.4 mm, a porous layer thickness of 0.15 mm, and a porosity of 50%. The inner surface has trapezoidal spiral grooves with an angle of 41° and a height of 0.25 mm, and 25 tubes per section. The overall heat transfer coefficient of this high-throughput heat exchanger is 30% higher than that of ordinary high-throughput heat exchangers, and the overall cost of the equipment is reduced by 10%. It also has the advantages of low process energy consumption and small installation space.

[0043] The embodiments described above do not constitute a limitation on the scope of protection of this application.

Claims

1. A high-efficiency evaporator based on high-flux heat exchange, characterized in that, The high-efficiency evaporator includes a heat exchange tube bundle located in the middle, the heat exchange tube bundle including several heat exchange tubes (3); a left tube box (2) is provided on one side of the heat exchange tube bundle, and a right tube box (7) is provided on the other side. A liquid inlet (1) is provided above the left tube box (2); a liquid outlet (8) is provided below the right tube box (7); The outer layer of the heat exchange tube (3) in the heat exchange tube bundle is a support plate (4); a gas outlet (5) is provided above the heat exchange tube bundle and a liquid inlet (9) is provided below it; The edges at both ends of the heat exchange tube (3) are smooth tubes; the inner and outer surfaces of the heat exchange section in the middle of the heat exchange tube (3) are processed with different structures, wherein the inner surface is densely covered with inner surface spiral ribs (22); and the outer surface is covered with outer surface pits (25).

2. The high-efficiency evaporator according to claim 1, characterized in that, The outer surface of the pitted surface (25) is covered with a porous outer surface layer (23).

3. The high-efficiency evaporator according to claim 1, characterized in that, The inner surface spiral rib (22) has a spiral angle of 30 to 41°, a height range of 0.2 to 0.3 mm, and a number of heads range of 20 to 30; the cross section of the inner surface spiral rib (22) is triangular or trapezoidal.

4. The high-efficiency evaporator according to claim 1, characterized in that, The spacing of the pits (25) on the outer surface ranges from 1.25 to 2.0 mm, and the height ranges from 0.3 to 0.4 mm; The outer surface pits (25) include circumferential grooves (21) and longitudinal grooves (24), with a helical angle range of 0.9 to 1.9°.

5. The high-efficiency evaporator according to claim 2, characterized in that, The thickness of the porous layer (23) on the outer surface ranges from 0.1 to 0.15 mm, and the porosity ranges from 40 to 60%.

6. The high-efficiency evaporator according to claim 1, characterized in that, The outer surface pitting (25) and the inner surface spiral ribs (22) are formed in one process.

Images