A ship heat and mass exchanger coated with high heat transfer anti-corrosion coating and preparation method thereof

Abstract

The present invention discloses a ship heat and mass exchanger coated with a high heat transfer anti-corrosion coating and a preparation method, belonging to the field of heat and mass transfer technology, comprising a main pipe and a mixing element, the mixing element comprising a straight plate section and a spiral section, the mixing element being fixed to the inner wall surface of the main pipe through the straight plate section, and the mixing element being coated with a high heat transfer anti-corrosion coating. The present invention adopts the above structure to reduce the pressure drop in the pipeline and improve its mixing uniformity, and can also enhance its heat exchange performance and effectively reduce NO x The coating of high heat transfer anti-corrosion coating on the surface of internal mixing element can improve the corrosion resistance of heat and mass exchanger working inside the element. The super hydrophobic surface has the effect of inhibiting scaling and self-cleaning. Multi-walled carbon nanotubes can enhance the heat transfer of fluid.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat and mass transfer, and in particular relates to a ship heat and mass exchanger coated with a high heat transfer anti-corrosion coating and a preparation method thereof. Background Art

[0002] In the marine shipping industry, diesel engines have become the main power source in the field of ship transportation due to their high thermal efficiency, good fuel economy, and wide power range. The fuel of diesel engines is mainly extracted from fossil energy. With the increasingly obvious trend of economic globalization, the demand for oil in various countries is also increasing, which makes oil resources increasingly depleted and environmental problems gradually worse. For this reason, the International Maritime Organization has begun to implement more stringent Tier III emission regulations. In order to effectively improve the energy efficiency of marine diesel engines and reduce NO x In order to reduce emissions, water-blended combustion technology was proposed, among which water-blended emulsified oil is the most widely used. Static mixers are an online, efficient mixing heat and mass exchange equipment that relies on periodically arranged spiral elements in the pipeline to continuously divide, deform, shift and mix the fluid. They are favored by the production fields of petroleum, chemical, food, and pharmaceuticals. Therefore, using static mixers as water-blending emulsifiers for marine diesel engines and emulsifiers for mixing water with fuel for heat and mass exchange can not only reduce the pressure drop in the pipeline and improve the mixing uniformity, but also enhance the heat exchange performance and effectively reduce NO x emissions.

[0003] Metal components are very susceptible to corrosion in marine atmosphere, hot and humid air environments, and other environments. When heat and mass exchange elements work in high temperature, high pressure, or high acidity and alkalinity environments, direct contact between metal materials and fluids will cause serious corrosion of the heat and mass exchange element structure. Heat and mass exchange elements are difficult to maintain and repair due to their delicate structure. Therefore, proposing protective measures against corrosion of heat and mass exchangers is of great significance for extending the service life of equipment, reducing enterprise maintenance costs, and improving their economic benefits. Summary of the invention

[0004] The present invention aims to provide a ship heat and mass exchanger coated with a high heat transfer anti-corrosion coating and a preparation method thereof, so as to solve the problems of high pressure drop in mixing uniformity and emission pollution caused by water emulsification of marine diesel engines and the internal corrosion problem of the heat and mass exchanger, and improve the heat exchange efficiency of the heat and mass exchanger.

[0005] To achieve the above object, the present invention provides a ship heat and mass exchanger coated with a high heat transfer anti-corrosion coating, comprising a main pipe and a mixing element. The mixing element comprises a straight plate section and a spiral section. The mixing element is fixed to the inner wall surface of the main pipe through the straight plate section. The mixing element is coated with a high heat transfer anti-corrosion coating.

[0006] Preferably, the spiral segment includes four blades, and the four blades are evenly divided into two groups and arranged at both ends of the straight plate segment. The torsion angle between the spiral segment and the straight plate segment is 30°.

[0007] Preferably, the two groups of blades at both ends of the straight plate segment are centrally symmetrical, the two blades at the same end of the straight plate segment are centrally symmetrical, and the misalignment angle of two adjacent blades is any one of 30°, 45°, 60° and 90°.

[0008] Preferably, the outer dimensions of the main pipe include a pipe length:pipe diameter ratio of 69:4.

[0009] Preferably, the outer dimensions of the straight section are length:width:height of 10:20:1.

[0010] Preferably, the high heat transfer anti-corrosion coating includes a first coating and a second coating from inside to outside.

[0011] Preferably, the first coating consists of bisphenol F diglycidyl ether, resorcinol diglycidyl ether, polyurethane, curing agent, ethyl acetate, nano ZrO2 and sodium linear alkylbenzene sulfonate.

[0012] Preferably, the second coating consists of a curing agent, ethyl acetate, nano ZrO2, multi-walled carbon nanotubes, TiO2, neopentyl glycol diheptanoate and heptadecafluorodecyl triethoxysilane.

[0013] The present invention also discloses a method for preparing a ship heat and mass exchanger coated with a high heat transfer anti-corrosion coating, comprising the following steps:

[0014] S1. Pretreatment of the heat and mass exchanger: Print out the mixing element of the heat and mass exchanger by 3D printing technology, put the mixing element into an organic acid chemical cleaning agent, heat it to 60-80°C and soak it for 1-2 hours, wash it with clean water after soaking, and dry it after washing until there is no obvious cleaning agent residue;

[0015] S2, preparation of the first coating: at room temperature, preheat bisphenol F diglycidyl ether, add resorcinol diglycidyl ether, amino ester, curing agent and ethyl acetate, stir magnetically until mixed uniformly to obtain a mixed solution, add nano ZrO2, ethyl acetate and linear alkyl benzene sodium sulfonate to the mixed solution, stir magnetically to obtain an epoxy resin mixed solution;

[0016] S3, preparation of component 1: TiO2 and nano ZrO2 are mixed and added to ethyl acetate for ultrasonic mixing, and then neopentyl glycol diheptanoate is added for magnetic stirring, and then neopentyl glycol diheptanoate, a curing agent and heptadecafluorodecyl triethoxysilane are added, and magnetic stirring is performed to obtain a super hydrophobic dispersion;

[0017] S4, preparation of component 2: adding carbon nanotubes to a mixture of concentrated sulfuric acid and concentrated nitric acid, heating and stirring at a constant temperature to acidify, cooling to room temperature, diluting with distilled water and filtering, washing the acidified carbon nanotubes with water and vacuum filtering until the filtrate is neutral for standby use;

[0018] S5, preparation of the second coating: deionized water, component 2, and neopentyl glycol diheptanoate are mixed and stirred in a constant temperature water bath, and after ultrasonic dispersion, they are added to component 1 and ultrasonicated to obtain the second coating;

[0019] S6, spraying: immerse the mixing element of the heat exchanger into the first coating, take it out after standing, and when the coating is cured, use an airless spray device to spray the second coating on the main board and top cover of the heat exchanger, and then cure it at 70°C;

[0020] S7. Sealing: Combine the mixing element of the heat and mass exchanger with the main pipe through sealing technology, and check the air tightness and water tightness.

[0021] Therefore, the present invention adopts the above-mentioned ship heat and mass exchanger coated with high heat transfer anti-corrosion coating and preparation method, and its beneficial effects are:

[0022] 1. The application of high heat transfer anti-corrosion coating can improve the oxidation resistance and corrosion resistance of the heat and mass exchanger during fluid heat exchange. Multi-walled carbon nanotubes can further optimize the configuration process of high heat transfer anti-corrosion coating and bring better heat transfer performance to the high heat transfer anti-corrosion coating.

[0023] 2. After the high heat transfer anti-corrosion coating is applied to the heat and mass exchanger for ships, a super hydrophobic surface is formed, which can inhibit the scaling in the static mixer and has a good self-cleaning function. Its medium resistance enables it to work normally in water, oil and other media for a long time;

[0024] 3. As an efficient mixing device, heat and mass exchangers are increasingly used in continuous mixing and heat transfer process industries. They can generate radial secondary flow, destroy the boundary layer, improve the internal mixing uniformity, reduce the pressure drop in the pipeline, and improve the heat transfer efficiency between the mainstream fluid and the boundary layer. The new design of the spiral plate generates transverse and longitudinal vortices in the tube, further enhancing heat transfer.

[0025] 4. Alternately use the infiltration technology and the airless nozzle technology to spray the inner coating of the new micro-channel heat exchanger, which increases the uniformity of the high heat transfer anti-corrosion coating on the inner wall of the new heat and mass exchanger, prevents the accumulation of the high heat transfer anti-corrosion coating or the occurrence of material shortages, and enhances the overall service life.

[0026] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is an overall model diagram of a heat and mass exchanger for a ship coated with a high heat transfer anti-corrosion coating according to the present invention;

[0028] Figure 2 It is a schematic diagram of a mixing element of a heat and mass exchanger for a ship coated with a high heat transfer anti-corrosion coating according to the present invention;

[0029] Figure 3 This is an axial schematic diagram of a heat and mass exchanger for a ship coated with a high heat transfer anti-corrosion coating according to the present invention;

[0030] Figure 4 It is a two-dimensional streamline diagram of the internal cross section of a heat and mass exchanger for a ship coated with a high heat transfer anti-corrosion coating according to the present invention;

[0031] Figure 5 The present invention discloses a three-dimensional streamline diagram of the interior of a heat and mass exchanger for a ship coated with a high heat transfer anti-corrosion coating.

[0032] Reference numerals:

[0033] 1. Main pipe; 2. Mixing element; 3. Straight plate section; 4. Blades; D-pipe diameter; l i -Inlet section length; l o - Length of outlet section; l m - length of mixing section; l e - length of mixing element; a- length of straight plate segment; b- width of straight plate segment; c- length of helical segment; α- torsion angle; β- misalignment angle; δ- thickness of mixing element. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0035] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0036] In addition, it should be understood that although this specification is described according to the implementation modes, not every implementation mode includes only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. These other implementation modes are also covered within the protection scope of the present invention.

[0037] The present invention is further described below with reference to the accompanying drawings and specific embodiments.

[0038] As the instruction manual Figure 1As shown, the present invention discloses a heat and mass exchanger for ships coated with a high heat transfer anti-corrosion coating. It is different from the currently common spiral type and grid type, and consists of a main pipe 1 and a mixing element 2. The overall dimensions of the heat and mass exchanger for ships are length: diameter, which is equal to the overall dimensions of the main pipe 1, and the pipe length L: pipe diameter D is 69:4.

[0039] This embodiment adopts a Cartesian coordinate system, and six mixing elements 2 are placed in the main pipe 1. The mixing section length l of the six mixing elements 2 in the main pipe 1 is m The mixing element 2 at the two ends of the main pipe 1 is 490 mm long and the distance from the two ends of the main pipe 1 is the inlet section length l. i = Exit section length l o =100mm, therefore, the length of main pipe 1 is L = l m +l i +l o =690mm, pipe diameter D is 40mm.

[0040] The structure of the mixing element 2 is as shown in the attached manual. Figure 2-3 As shown, the mixing element 2 includes a straight plate section 3 and a spiral section. The mixing element 2 is fixed to the inner wall surface of the main pipe 1 through the straight plate section 3. The torsion angle α between the spiral section and the straight plate section 3 is 30°, so the spiral section rotates by a corresponding angle of 30° relative to the vertical flow direction of the fluid.

[0041] The spiral section includes four blades 4, which are evenly divided into two groups and arranged at the two ends of the straight plate section 3. The two groups of blades 4 at the two ends of the straight plate section 3 are symmetrical in center, and the two adjacent blades 4 at the same end of the straight plate section 3 are symmetrical in center. The misalignment angle of the two adjacent blades 4 is any one of 30°, 45°, 60° and 90°. The length: width: height of the straight plate section 3 in the mixing element 2 is 10:20:1. In this embodiment, the length of the mixing element 2 is l e is 87.5 mm, the thickness δ of the mixing element 2 is 2 mm, the length a of the straight plate section 3 is 20 mm, the width b of the straight plate section 3 is 40 mm, and the length c of the spiral section is 40 mm.

[0042] The specific parameters of the ship heat and mass exchanger in this embodiment are shown in the following table:

[0043] Table 1 Heat and mass exchanger parameters

[0044]

[0045] As the instruction manual Figure 4 And the instruction manual Figure 5 As shown, attached Figure 4The two-dimensional streamline diagram of the internal cross-section of the ship heat and mass exchanger is shown. It can be seen from the figure that the local fluid of the twisted blade is divided and disturbed by the element, and the velocity field changes to a certain extent with the rotation of the blade. Since the blade divides the flow area evenly into two parts, the flow of the fluid is symmetrical. When (a) Z = 145mm, the fluid flows through the midpoint of the first rectangular plate. At this time, the fluid is divided into two parts with good symmetry. The combination of two forced vortices with opposite vortex directions forms a pair of Dean vortices, which are smaller than the pipe diameter and help to enhance heat transfer. When (b) Z = 185mm, the Dean vortex gradually weakens, and a new longitudinal vortex gradually merges before the end edge of the central rectangular plate and is generated in the mainstream area. When the fluid flows through the middle of the element, the two pairs of secondary flow areas are completely merged into a pair of large-scale, high-intensity secondary flow areas symmetrical around the center of the element. When (c) Z = 225 mm, the fluid flows through the rectangular plate again. At this time, a forced vortex is generated again near the rectangular plate, and the overall flow becomes more uniform. The secondary flow zone begins to gradually differentiate into two pairs and form a periodic change.

[0046] By periodically mixing and cutting the fluid, the fluid produces a larger velocity gradient, thereby generating a greater shear force, causing the viscosity of the fluid to change, which is beneficial to reducing the pressure drop. At the same time, the overall velocity of the fluid is closer to unity, and the longitudinal vortex formed destroys the boundary layer, making the boundary layer thinner. The heat exchange between the fluid and the wall near the wall is stronger, and the heat transfer effect is better.

[0047] Attached Figure 5 The three-dimensional streamline diagram inside the heat and mass exchanger for ships is shown. As shown in the figure, when the fluid just enters the pipeline, it is turbulent and flows very regularly. When it flows to the first spiral plate, the fluid separates, produces spiral flow, and begins to compress the boundary layer. It can be clearly seen that forced vortices in opposite directions are generated at the rectangular plate. Transverse vortices are also generated between the spiral plate and the pipe wall. Unlike the longitudinal vortex, the transverse vortex compresses the boundary layer, making the boundary layer thinner and enhancing the heat exchange capacity of the fluid near the wall. The spiral plate induces the fluid to separate. After passing through the rectangular plate, the spiral plate induces the fluid to mix again, with obvious flow characteristics. After flowing through the last spiral plate, the fluid develops into complete turbulence, and the overall flow is spiral. It has a significant effect on the destruction of the boundary layer.

[0048] The mixing element 2 can generate radial secondary flow, destroy the boundary layer, improve the internal mixing uniformity, reduce the pressure drop in the pipeline, and improve the heat transfer efficiency between the mainstream fluid and the boundary layer. The new spiral plate design in the mixing element 2 generates transverse vortices and longitudinal vortices in the tube, further enhancing heat exchange.

[0049] The mixing element 2 of the heat and mass exchanger is coated with a high heat transfer anti-corrosion coating, which is a first coating and a second coating from the inside to the outside. The present invention adopts a heat and mass exchanger for ships coated with a high heat transfer anti-corrosion coating of the above structure. The coating of the high heat transfer anti-corrosion coating can improve the corrosion resistance of the heat and mass exchanger in fluid heat exchange work, and the formed super-hydrophobic surface has the effect of inhibiting scaling and self-cleaning, and the multi-walled carbon nanotubes can enhance the heat transfer of the fluid.

[0050] The first coating consists of bisphenol F diglycidyl ether, resorcinol diglycidyl ether, polyurethane, curing agent, ethyl acetate, nano ZrO2 and sodium linear alkylbenzene sulfonate.

[0051] The second coating consists of a curing agent, ethyl acetate, nano ZrO2, multi-walled carbon nanotubes, TiO2, neopentyl glycol diheptanoate and heptadecafluorodecyl triethoxysilane.

[0052] The present invention also discloses a method for preparing a heat and mass exchanger for a ship coated with a high heat transfer anti-corrosion coating:

[0053] S1. Pretreatment of the heat and mass exchanger: Print out the mixing element 2 of the heat and mass exchanger by 3D printing technology, put the mixing element 2 into an organic acid chemical cleaning agent, heat it to 60-80° C. and soak it for 1-2 hours, wash it with clean water after soaking, and dry it after washing until there is no obvious cleaning agent residue;

[0054] S2, preparation of the first coating: at room temperature, preheat bisphenol F diglycidyl ether, add resorcinol diglycidyl ether, amino ester, curing agent and ethyl acetate, stir magnetically until mixed uniformly to obtain a mixed solution, add nano-ZrO2, ethyl acetate and sodium linear alkylbenzene sulfonate, stir magnetically to obtain an epoxy resin mixed solution;

[0055] S3, preparation of component 1: TiO2 and nano ZrO2 are mixed and added to ethyl acetate for ultrasonic mixing, and then neopentyl glycol diheptanoate is added for magnetic stirring, and then neopentyl glycol diheptanoate, a curing agent and heptadecafluorodecyl triethoxysilane are added, and magnetic stirring is performed to obtain a super hydrophobic dispersion;

[0056] S4, preparation of component 2: adding carbon nanotubes to a mixture of concentrated sulfuric acid and concentrated nitric acid, heating and stirring at a constant temperature to acidify, cooling to room temperature, diluting with distilled water and filtering, washing the acidified carbon nanotubes with water and vacuum filtering until the filtrate is neutral for standby use;

[0057] S5, preparation of the second coating: deionized water, component 2, and neopentyl glycol diheptanoate are mixed and stirred in a constant temperature water bath, and after ultrasonic dispersion, they are added to component 1 and ultrasonicated to obtain the second coating;

[0058] S6, spraying: immerse the mixing element 2 of the heat and mass exchanger into the first coating, take it out after standing, and when the coating is cured, use an airless spray device to spray the second coating on the main board and the top cover of the heat exchanger, and then cure it at 70°C;

[0059] S7. Sealing: Combine the mixing element 2 of the heat and mass exchanger with the main pipe 1 through sealing technology, and check the air tightness and water tightness.

[0060] Therefore, the present invention discloses a heat and mass exchanger for ships coated with a high heat transfer anti-corrosion coating, which can reduce the pressure drop in the pipeline and improve the mixing uniformity for the water emulsification of marine diesel engines, and can also enhance the heat exchange performance and effectively reduce NO x In addition, the high heat transfer anti-corrosion coating applied to the internal mixing element can improve the corrosion resistance of the heat and mass exchanger when working inside the element. The super hydrophobic surface formed has the effect of inhibiting scaling and self-cleaning, and the multi-walled carbon nanotubes can enhance the heat transfer of the fluid.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for preparing a ship heat and mass exchanger coated with a high heat transfer anti-corrosion coating, characterized in that: The invention comprises a main pipe and a mixing element, wherein the mixing element comprises a straight plate section and a spiral section, the mixing element is fixed to the inner wall surface of the main pipe through the straight plate section, and the mixing element is coated with a high heat transfer anti-corrosion coating; The following steps are involved: S1. Pretreatment of the heat and mass exchanger: Print out the mixing element of the heat and mass exchanger by 3D printing technology, put the mixing element into an organic acid chemical cleaning agent, heat it to 60-80°C and soak it for 1-2 hours, wash it with clean water after soaking, and dry it after washing until there is no obvious cleaning agent residue; S2, preparation of the first coating: at room temperature, preheat bisphenol F diglycidyl ether, add resorcinol diglycidyl ether, amino ester, curing agent and ethyl acetate, stir magnetically until mixed uniformly to obtain a mixed solution, add nano ZrO2, ethyl acetate and linear alkyl benzene sodium sulfonate to the mixed solution, stir magnetically to obtain an epoxy resin mixed solution; S3, preparation of component 1: TiO2 and nano ZrO2 are mixed and added to ethyl acetate for ultrasonic mixing, and then neopentyl glycol diheptanoate is added for magnetic stirring, and then neopentyl glycol diheptanoate, a curing agent and heptadecafluorodecyl triethoxysilane are added, and magnetic stirring is performed to obtain a super hydrophobic dispersion; S4, preparation of component 2: adding carbon nanotubes to a mixture of concentrated sulfuric acid and concentrated nitric acid, heating and stirring at a constant temperature to acidify, cooling to room temperature, diluting with distilled water and filtering, washing the acidified carbon nanotubes with water and vacuum filtering until the filtrate is neutral for standby use; S5, preparation of the second coating: deionized water, component 2, and neopentyl glycol diheptanoate are mixed and stirred in a constant temperature water bath, and after ultrasonic dispersion, the mixture is added to component 1 and ultrasonic dispersion is continued to obtain the second coating; S6, spraying: immerse the mixing element of the heat exchanger into the first coating, take it out after standing, and when the coating is cured, use an airless spray device to spray the second coating on the main board and top cover of the heat exchanger, and then cure it at 70°C; S7. Sealing: Combine the mixing element of the heat and mass exchanger with the main pipe through sealing technology, and check the air tightness and water tightness.

2. The method for preparing a ship heat and mass exchanger coated with a high heat transfer anti-corrosion coating according to claim 1, characterized in that: The spiral section includes four blades, which are evenly divided into two groups and arranged at both ends of the straight plate section. The torsion angle between the spiral section and the straight plate section is 30°.

3. The method for preparing a ship heat and mass exchanger coated with a high heat transfer anti-corrosion coating according to claim 2, characterized in that: The two groups of blades at both ends of the straight plate segment are centrally symmetrical, the two blades at the same end of the straight plate segment are centrally symmetrical, and the misalignment angle of two adjacent blades is any one of 30°, 45°, 60° and 90°.

4. The method for preparing a ship heat and mass exchanger coated with a high heat transfer anti-corrosion coating according to claim 1, characterized in that: The outer dimensions of the main pipe are that the pipe length:pipe diameter is 69:

4.

5. The method for preparing a ship heat and mass exchanger coated with a high heat transfer anti-corrosion coating according to claim 1, characterized in that: The outer dimensions of the straight section are length: width: height of 10:20:

1.

6. The method for preparing a ship heat and mass exchanger coated with a high heat transfer anti-corrosion coating according to claim 1, characterized in that: The high heat transfer anti-corrosion coating includes a first coating and a second coating from the inside to the outside.

7. The method for preparing a ship heat and mass exchanger coated with a high heat transfer anti-corrosion coating according to claim 6, characterized in that: The first coating consists of bisphenol F diglycidyl ether, resorcinol diglycidyl ether, polyurethane, curing agent, ethyl acetate, nano ZrO2 and linear alkyl benzene sodium sulfonate.

8. The method for preparing a ship heat and mass exchanger coated with a high heat transfer anti-corrosion coating according to claim 6, characterized in that: The second coating consists of a curing agent, ethyl acetate, nano ZrO2, multi-walled carbon nanotubes, TiO2, neopentyl glycol diheptanoate and heptadecafluorodecyl triethoxysilane.

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