A rapid leak-sealing method for condensers based on the click reaction of mercapto-isocyanates.

Abstract

This invention proposes a rapid condenser plugging method based on a mercapto-isocyanate click reaction. First, a mixture containing mercapto and isocyanate groups is prepared, and a catalyst is added to obtain a plugging agent suitable for plugging condenser heat exchangers. When plugging is needed, the plugging agent is added to the condenser heat exchange tubes. Under the dual catalytic action of the catalyst and water vapor within the heat exchange tubes, a rapid plugging effect is achieved. The rapid plugging method proposed in this invention features simple plugging agent preparation, a fast plugging process, and adaptability to various heat exchange tube sizes and different surface cleanliness levels. Furthermore, the presence of water vapor within the heat exchange tubes accelerates the solidification and plugging process of the mixture. This method, based on click chemical reaction for plugging, overcomes the shortcomings of traditional physical plugging techniques, improving plugging efficiency and effectiveness.

Description

Technical Field

[0001] This invention belongs to the field of condenser leak treatment technology, specifically relating to a rapid condenser leak sealing method based on mercapto-isocyanate click reaction. Background Technology

[0002] Condensers, as crucial components of the steam-water system in power generating units, are widely used in thermal and nuclear power plants, and their stable operation is paramount. However, condenser heat exchanger tube leaks occur frequently. This is because the cooling water outside the condenser heat exchanger tubes is typically of poor quality, especially in coastal power plants using seawater direct cooling. Seawater has a much higher salinity than freshwater, with a high sodium content. + and Cl - The content of these elements is very high; once Na... + and Cl - If leaks into the steam-water system, it will cause a sharp drop in the quality of steam and water in the unit, resulting in serious consequences such as corrosion and salt accumulation in the steam turbine and corrosion and scaling in thermal equipment.

[0003] Traditional methods for dealing with condenser leaks include adding sawdust and plugging. Adding sawdust can be effective for minor leaks in operating units, but it is often ineffective when the leak diameter is large. Plugs are made of copper or rubber, tailored to the dimensions of the condenser tubes. To ensure the effectiveness of plugging, high requirements are placed on the matching degree between the plug size and the condenser tubes, the material of the plug, and its service life. If the plug corrodes and leaks, the plug size is unsuitable, or foreign objects are present inside the condenser tube wall during the plugging process, the plugging effect will decrease, failing to completely isolate the leaking condenser tubes and leading to serious consequences such as turbine corrosion and salt buildup, and scale buildup in thermal equipment.

[0004] Therefore, developing a rapid leak-sealing method for condensers that is compatible with the size of the condenser heat exchange tubes and has no requirements on the cleanliness of the inner wall of the heat exchange tubes will help improve the leak-sealing effect and thus ensure the safe operation of the unit. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art, and proposes a rapid leak sealing method for condensers based on mercapto-isocyanate click reaction.

[0006] Embodiments of the present invention provide a rapid condenser plugging method based on the click reaction of mercapto-isocyanate, the method comprising:

[0007] A sealant is obtained by mixing a compound containing thiol groups and a compound containing isocyanate groups at room temperature in a thiol:isocyanate molar ratio of 1:1.

[0008] Mix the sealant and catalyst thoroughly.

[0009] The leak-sealing agent, mixed with a catalyst, is filled into the leaking condenser heat exchange tube. The leak-sealing agent is then allowed to solidify on its own, thus completing the rapid sealing of the condenser heat exchange tube.

[0010] In some possible embodiments, the thiol-containing compound is a polyfunctional thiol compound.

[0011] In some possible embodiments, the mercapto-containing compound includes trimethylolpropane trimercaptopropionate, pentaerythritol tetramercaptopropionate, or triphenyl-2,3,6,7,10,11-hexathiol.

[0012] In some possible embodiments, the isocyanate-containing compound is a polyfunctional isocyanate compound.

[0013] In some possible embodiments, the isocyanate-containing compound includes 1,6-hexamethylene diisocyanate, isophorone diisocyanate, or toluene-2,4-diisocyanate.

[0014] In some possible embodiments, the catalyst is a catalyst for the mercapto-isocyanate reaction.

[0015] In some possible embodiments, the catalyst comprises dibutyltin diacetate, triethylamine, or an imidazole compound.

[0016] In some possible embodiments, the mass ratio of the plugging agent to the catalyst should be 0.1% to 0.5%.

[0017] In some possible embodiments, the step of filling the leaking condenser heat exchange tube with a plugging agent mixed with a catalyst and waiting for the plugging agent to solidify on its own can complete the rapid plugging of the condenser heat exchange tube, including:

[0018] The leak-sealing agent mixed with the catalyst is filled into the leaking condenser heat exchange tube. Under the combined catalysis of the catalyst and the moisture in the heat exchange tube, a mercapto-isocyanate click reaction occurs, which solidifies to form a polymer resin material, thus achieving rapid condenser leak sealing.

[0019] In some possible embodiments, the curing and sealing time is controlled within 5 to 30 minutes, and with the contact of moisture, the sealing agent will further cure and form hydrogen bonds with the heat exchange tube wall, strengthening the adhesion strength to the tube wall and enhancing the sealing effect.

[0020] Compared with the prior art, the present invention provides a rapid condenser plugging method based on mercapto-isocyanate click reaction, which has the following beneficial effects:

[0021] First, the rapid reaction rate of mercapto-isocyanate allows for quick condenser leak sealing. Second, the generally high humidity inside the heat exchange tubes accelerates the mercapto-isocyanate reaction, further increasing sealing efficiency. Furthermore, the polymer resin formed after mercapto-isocyanate curing can form hydrogen bonds with the condenser tube walls, strengthening the adhesion between the sealant and the heat exchange tubes, thus enhancing the sealing effect and preventing leaks that could contaminate the condensate. Finally, because the sealant is a mixture of compounds with a certain viscosity, it can seal leaks in condenser heat exchange tubes of different sizes, and the process does not require high cleanliness of the tube walls, making it suitable for various condenser tube types. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a scanning electron microscope image of the polymer resin formed after the mercapto-isocyanate plugging agent of this invention has been cured. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0025] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale, and techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail; however, where appropriate, the illustrated techniques, methods, and apparatus should be considered part of the specification. In all the examples shown and discussed herein, any other specific example may have different values. It should be noted that similar symbols and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0026] In the description of the embodiments of the present invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In the embodiments of the present invention, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in the embodiments of the present invention, as well as the features of different embodiments or examples.

[0027] This invention provides a rapid condenser plugging method based on the click reaction of mercapto-isocyanate, the method comprising the following steps:

[0028] Step 1: Mix the compound containing thiol groups and the compound containing isocyanate groups at room temperature in a 1:1 molar ratio of thiol groups to isocyanate groups to obtain the sealing agent.

[0029] Specifically, in this step, the thiol-containing compound is a polyfunctional thiol compound. For example, such a thiol-containing compound includes, but is not limited to, trimethylolpropane trimercaptopropionate, pentaerythritol tetramercaptopropionate, or triphenylene-2,3,6,7,10,11-hexathiol. The isocyanate-containing compound is a polyfunctional isocyanate compound; for example, such an isocyanate compound includes, but is not limited to, 1,6-hexamethylenediisocyanate, isophorone diisocyanate, or toluene-2,4-diisocyanate.

[0030] Step 2: Mix the sealant and catalyst evenly.

[0031] Specifically, in this step, the catalyst can be a catalyst for the mercapto-isocyanate reaction. For example, the catalyst includes, but is not limited to, dibutyltin diacetate, triethylamine, or imidazole compounds.

[0032] In some embodiments, the mass ratio of the plugging agent to the catalyst is 0.1% to 0.5%.

[0033] Step 3: Fill the leaking condenser heat exchange tube with the sealant mixed with the catalyst and wait for the sealant to solidify on its own to complete the rapid sealing of the condenser heat exchange tube.

[0034] Specifically, in this step, the plugging agent mixed with the catalyst is filled into the leaking condenser heat exchange tube. Under the combined catalysis of the catalyst and the moisture in the heat exchange tube, a mercapto-isocyanate click reaction occurs, which solidifies to form a polymer resin material, thereby achieving rapid plugging of the condenser leak.

[0035] In some embodiments, the curing and sealing time is controlled within 5 to 30 minutes. As moisture comes into contact with the sealant, it will further solidify and form hydrogen bonds with the heat exchange tube wall, thereby strengthening the adhesion to the tube wall and enhancing the sealing effect.

[0036] In the rapid condenser plugging method based on the click reaction of mercapto-isocyanate in this embodiment of the invention, the scanning electron microscope image of the polymer resin formed after the mercapto-isocyanate plugging agent has been cured is shown below. Figure 1 As shown.

[0037] Compared with the prior art, the rapid condenser plugging method based on the click reaction of mercapto-isocyanate according to an embodiment of the present invention has the following beneficial effects:

[0038] First, the rapid reaction rate of mercapto-isocyanate allows for quick condenser leak sealing. Second, the generally high humidity inside the heat exchange tubes accelerates the mercapto-isocyanate reaction, further increasing sealing efficiency. Furthermore, the polymer resin formed after mercapto-isocyanate curing can form hydrogen bonds with the condenser tube walls, strengthening the adhesion between the sealant and the heat exchange tubes, thus enhancing the sealing effect and preventing leaks that could contaminate the condensate. Finally, because the sealant is a mixture of compounds with a certain viscosity, it can seal leaks in condenser heat exchange tubes of different sizes, and the process does not require high cleanliness of the tube walls, making it suitable for various condenser tube types.

[0039] The technical principles of the present invention will be explained below.

[0040] Click reactions are characterized by simple reaction conditions (no solvent or water required), fast reaction rates, high yields, few byproducts, and environmental friendliness. Typical click reactions include Cu-catalyzed azide-alkyne reactions and Diels-Alder reactions between alkenes. In addition, mercapto-isocyanate reactions are also representative of click chemistry due to their high reactivity, fast reaction rates, and low byproducts.

[0041] The click reaction of mercapto-isocyanate is a nucleophilic addition reaction, and its reaction principle is as follows.

[0042]

[0043] In this Michael addition reaction, under the action of a catalyst, the thiol is converted into a highly nucleophilic thioanion, and the carbonyl group of the isocyanate is polarized and exhibits electron-deficient characteristics, facilitating attack by the nucleophilic group. The reaction generates an anionic intermediate, which then transfers electrons to the thiol and abstracts a hydrogen atom from the thiol, thereby forming polythiourethane.

[0044] Typically, with the aid of a catalyst, this reaction can be completed in just a few minutes. Therefore, it is a fast and convenient option for use as a sealing agent for condenser heat exchanger tubes.

[0045] The present invention will now be further described with reference to the embodiments:

[0046] Example 1:

[0047] Weigh 10g of trimethylolpropane trimercaptopropionate and 6.33g of 1,6-hexamethylene diisocyanate, add 0.02g of dibutyltin diacetate catalyst, and mix thoroughly to obtain the sealing agent. Inject the sealing agent into the leaking condenser heat exchange tube and allow it to solidify naturally to achieve rapid sealing of the condenser heat exchange tube.

[0048] Example 2:

[0049] Weigh 10g of trimethylolpropane trimercaptopropionate and 8.37g of isophorone diisocyanate, add 0.02g of triethylamine catalyst, and mix thoroughly to obtain the sealing agent. Inject the sealing agent into the leaking condenser heat exchange tube and allow it to solidify naturally to achieve rapid sealing of the condenser heat exchange tube.

[0050] Example 3:

[0051] Weigh 10g of trimethylolpropane trimercaptopropionate and 6.55g of toluene-2,4-diisocyanate, add 0.03g of an imidazole-based catalyst, and mix thoroughly to obtain the sealing agent. Inject the sealing agent into the leaking condenser heat exchange tube and allow it to solidify naturally to achieve rapid sealing of the condenser heat exchange tube.

[0052] Example 4:

[0053] Weigh out 10g of pentaerythritol tetramercaptopropionate and 6.88g of 1,6-hexamethylene diisocyanate, add 0.03g of dibutyltin diacetate catalyst, and mix thoroughly to obtain the sealing agent. Inject the sealing agent into the leaking condenser heat exchange tube and allow it to solidify naturally to achieve rapid sealing of the condenser heat exchange tube.

[0054] Example 5:

[0055] Weigh 10g of pentaerythritol tetramercaptopropionate and 9.09g of isophorone diisocyanate, add 0.06g of triethylamine catalyst, and mix thoroughly to obtain the sealing agent. Inject the sealing agent into the leaking condenser heat exchange tube and allow it to solidify naturally to achieve rapid sealing of the condenser heat exchange tube.

[0056] Example 6:

[0057] Weigh 10g of pentaerythritol tetramercaptopropionate and 7.12g of toluene-2,4-diisocyanate, add 0.05g of imidazole-based catalyst, and mix thoroughly to obtain the sealing agent. Inject the sealing agent into the leaking condenser heat exchange tube and allow it to solidify naturally to achieve rapid sealing of the condenser heat exchange tube.

[0058] Example 7:

[0059] Weigh 10g of phenyl-2,3,6,7,10,11-hexathiol and 11.99g of 1,6-hexamethylene diisocyanate, add 0.09g of dibutyltin diacetate catalyst, and mix thoroughly to obtain the sealing agent. Inject the sealing agent into the leaking condenser heat exchange tube and allow it to solidify naturally to achieve rapid sealing of the condenser heat exchange tube.

[0060] Example 8:

[0061] Weigh 10g of triphenyl-2,3,6,7,10,11-hexathiol and 15.85g of isophorone diisocyanate, add 0.10g of triethylamine catalyst, and mix thoroughly to obtain the sealing agent. Inject the sealing agent into the leaking condenser heat exchange tube and allow it to solidify naturally to achieve rapid sealing of the condenser heat exchange tube.

[0062] Example 9:

[0063] Weigh 10g of phenyl-2,3,6,7,10,11-hexathiol and 12.42g of toluene-2,4-diisocyanate, add 0.11g of an imidazole-based catalyst, and mix thoroughly to obtain the sealing agent. Inject the sealing agent into the leaking condenser heat exchange tube and allow it to solidify naturally to achieve rapid sealing of the condenser heat exchange tube.

[0064] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A rapid leak sealing method for condensers based on the click reaction of mercapto-isocyanate, characterized in that, The method includes: A sealant is obtained by mixing a compound containing thiol groups and a compound containing isocyanate groups at room temperature in a thiol:isocyanate molar ratio of 1:

1. The plugging agent and catalyst are mixed evenly; wherein the mass ratio of the plugging agent to the catalyst should be 0.1% to 0.5%. The leak-sealing agent mixed with the catalyst is filled into the leaking condenser heat exchange tube and left to cure on its own to quickly seal the leak in the condenser heat exchange tube. Specifically, the leak-sealing agent mixed with the catalyst is filled into the leaking condenser heat exchange tube. Under the combined catalysis of the catalyst and the moisture in the heat exchange tube, a mercapto-isocyanate click reaction occurs, which cures to form a polymer resin material, thus achieving rapid sealing of the condenser leak. The curing and sealing time is controlled within 5 to 30 minutes. As the moisture comes into contact with the water, the sealing agent will further solidify and form hydrogen bonds with the heat exchange tube wall, strengthening the adhesion to the tube wall and enhancing the sealing effect.

2. The rapid condenser plugging method based on mercapto-isocyanate click reaction according to claim 1, characterized in that, The compound containing a thiol group is a polyfunctional thiol compound.

3. The rapid condenser plugging method based on mercapto-isocyanate click reaction according to claim 2, characterized in that, The thiol-containing compounds include trimethylolpropane trimercaptopropionate, pentaerythritol tetramercaptopropionate, or triphenyl-2,3,6,7,10,11-hexathiol.

4. The rapid condenser plugging method based on mercapto-isocyanate click reaction according to claim 1, characterized in that, The isocyanate-containing compound is a polyfunctional isocyanate compound.

5. The rapid condenser plugging method based on mercapto-isocyanate click reaction according to claim 4, characterized in that, The isocyanate-containing compounds include 1,6-hexamethylene diisocyanate, isophorone diisocyanate, or toluene-2,4-diisocyanate.

6. The rapid condenser plugging method based on mercapto-isocyanate click reaction according to claim 1, characterized in that, The catalyst is a catalyst for the mercapto-isocyanate reaction.

7. The rapid condenser plugging method based on mercapto-isocyanate click reaction according to claim 6, characterized in that, The catalyst includes dibutyltin diacetate, triethylamine, or an imidazole compound.

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