Chemical cleaning reagent for condenser of thermal power plant, preparation method and application thereof

Abstract

This invention discloses a chemical cleaning reagent for condensers in thermal power plants, its preparation method, and its application. By mass percentage, the raw materials of the chemical cleaning reagent include 0.3-3% aminosulfonic acid, 0.1-1% nitric acid, 0.2-2% glycolic acid, 0.02-0.05% sodium isoascorbate, 0.1-0.2% Lan-826 corrosion inhibitor, 0.2-0.4% benzotriazole, 0.02-0.05% dialkyl phosphate, and the balance being water. It is suitable for cleaning calcium and magnesium scale in condensers, achieving a descaling rate of over 98%. Furthermore, the combination of corrosion inhibitor Lan-826 and benzotriazole can achieve a very low corrosion rate for heat exchange tubes, less than 0.05 g / (m²). 2 ·h).

Description

Technical Field

[0001] This invention belongs to the field of chemical cleaning technology for condensers in thermal power plants, specifically relating to a chemical cleaning reagent for condensers in thermal power plants, its preparation method, and its application. Background Technology

[0002] Condensers play a crucial role in thermal power plants. As large heat exchange equipment, they are an indispensable part of the steam turbine, and their operating status directly affects the turbine's work efficiency and overall performance. The main function of the condenser is to condense the turbine exhaust steam into water through a heat exchange process to maintain the turbine's vacuum and thermal efficiency.

[0003] However, scaling in condenser heat exchange pipes is a common and unavoidable problem during the operation of condensers in thermal power plants. Because the circulating water used in thermal power plants inevitably contains various impurities in nature, such as suspended solids, dissolved salts, and microorganisms, these impurities may deposit on the inner walls of the condenser heat exchange pipes as the circulating water passes through, forming scale layers of varying degrees and types.

[0004] The presence of scale has a significant adverse impact on the heat exchange efficiency of condensers. Since the thermal conductivity of scale is much lower than that of metal pipes, scale formation increases the thermal resistance of the heat exchange pipes, leading to a larger temperature difference between the condenser outlet steam and the cooling water inlet. This not only reduces the condenser's heat exchange efficiency, preventing sufficient condensation of turbine exhaust steam and thus affecting the turbine's work capacity, but also reduces the unit's load-bearing capacity, increases energy consumption, and decreases economic efficiency.

[0005] Chemical cleaning is an effective measure to prevent heat exchange tubes from becoming less efficient due to corrosion and scaling, and to prevent a decrease in condenser vacuum. It is also one of the effective measures to improve condenser thermal efficiency and ensure the safe and economical operation of the unit. However, commonly used chemical cleaning agents on the market, such as hydrofluoric acid, sulfuric acid, citric acid, nitric acid, and hydrochloric acid, although they have a certain ability to dissolve scale, often result in corrosion after cleaning.

[0006] Therefore, when selecting chemical cleaning agents, it is necessary to consider both their strong scale-dissolving ability and low corrosivity to stainless steel pipes in order to meet the urgent need for chemical cleaning of condenser heat exchange tubes and solve existing problems. Summary of the Invention

[0007] In order to overcome the shortcomings of the prior art, the present invention aims to provide a chemical cleaning reagent for condensers in thermal power plants, its preparation method and application. This chemical cleaning reagent has high descaling efficiency and low corrosivity to copper and stainless steel pipes, thereby solving the technical problem of existing chemical cleaning agents causing corrosion to stainless steel pipes.

[0008] To achieve the above objectives, the present invention employs the following technical solution:

[0009] This invention provides a chemical cleaning reagent for condensers in thermal power plants. The raw materials of the chemical cleaning reagent, by mass percentage, include 0.3-3% aminosulfonic acid, 0.1-1% nitric acid, 0.2-2% glycolic acid, 0.02-0.05% sodium isoascorbate, 0.1-0.2% Lan-826 corrosion inhibitor, 0.2-0.4% benzotriazole, 0.02-0.05% dialkyl phosphate, with the balance being water.

[0010] In one embodiment, when the chemical cleaning reagent is prepared, the ratio of nitric acid, glycolic acid, and aminosulfonic acid is 1:2:3.

[0011] In one embodiment, when the chemical cleaning reagent is prepared, the ratio of Lan-826 corrosion inhibitor to benzotriazole is 1:2.

[0012] In one embodiment, the pH value of the chemical cleaning agent is maintained at 3-4.

[0013] The present invention also provides a method for preparing the above-mentioned chemical cleaning reagent for condensers of thermal power plants, comprising the following steps: adding aminosulfonic acid, nitric acid, glycolic acid, sodium isoascorbate, Lan-826 corrosion inhibitor, benzotriazole, and dialkyl phosphate to water in sequence to obtain the chemical cleaning reagent for condensers of thermal power plants.

[0014] The present invention also provides an application of the above-mentioned chemical cleaning reagent for condensers in thermal power plants in the condenser cleaning process of thermal power plants.

[0015] In one embodiment, the cleaning temperature when using the chemical cleaning agent is 45-55°C.

[0016] In one embodiment, the chemical cleaning agent is used for cyclic cleaning.

[0017] In one embodiment, the chemical cleaning agent has a descaling rate of greater than 98%.

[0018] In one embodiment, the corrosion rate of the chemical cleaning agent is less than 0.05 g / (m²). 2 ·h).

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] This invention provides a chemical cleaning agent for condensers in thermal power plants, suitable for cleaning calcium and magnesium scale in condensers. Firstly, this chemical cleaning agent contains various corrosion inhibitors and desiccant, such as Lan-826 corrosion inhibitor and benzotriazole. These components effectively inhibit corrosion of stainless steel pipes during the cleaning process, protecting the pipe surface from damage. Lan-826 corrosion inhibitor is a highly efficient corrosion inhibitor that forms a protective film on the metal surface, preventing direct contact between corrosive components in the cleaning agent and the metal. Benzotriazole has a dual effect of inhibiting metal corrosion and oxidation, further enhancing the corrosion inhibition effect. Secondly, this invention also selects aminosulfonic acid, nitric acid, and glycolic acid as the main cleaning agent components. These components have excellent scale dissolving capabilities, effectively removing scale and impurities (calcium and magnesium scale and other impurities) from the condenser heat exchange tubes. Simultaneously, through reasonable proportioning and concentration control, these cleaning agent components can reduce corrosion of stainless steel pipes while exerting a cleaning effect. Furthermore, the addition of sodium isoascorbate also helps improve the corrosion inhibition performance of the cleaning agent. Sodium isoascorbate, as an antioxidant, can prevent unnecessary oxidation reactions on metal surfaces, especially preventing copper plating, thus protecting the pipes from damage. Dimethyl alkyl phosphate, as an auxiliary corrosion inhibitor, can further enhance the corrosion inhibition effect of the cleaning agent, protecting the pipes from damage. Simultaneously, it also has an antifoaming effect, reducing foam generated during cleaning and improving cleaning efficiency. In summary, this invention effectively solves the technical problem of existing chemical cleaning agents causing corrosion to stainless steel pipes by adding multiple corrosion inhibitors and suppressants, selecting cleaning agent components with excellent scale-dissolving capabilities, and rationally controlling their ratio and concentration. This chemical cleaning agent not only has highly efficient cleaning capabilities but also protects the pipes from damage, extends the service life of the condenser, and improves the safety and economy of the unit. Detailed Implementation

[0021] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0022] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0023] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0024] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0025] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0026] This invention provides a chemical cleaning reagent for condensers in thermal power plants, its preparation method, and its application.

[0027] On the one hand, a chemical cleaning reagent for condensers in thermal power plants is provided, which, by mass percentage, comprises 0.3-3% aminosulfonic acid, 0.1-1% nitric acid, 0.2-2% glycolic acid, 0.02-0.05% sodium isoascorbate, 0.1-0.2% Lan-826 corrosion inhibitor, 0.2-0.4% benzotriazole, 0.02-0.05% dialkyl phosphate, with the balance being water.

[0028] Specifically, the pH value of this chemical cleaning agent is maintained at 3-4.

[0029] The present invention provides a chemical cleaning agent for condensers in thermal power plants. This cleaning agent, through a carefully designed formula, achieves highly efficient cleaning capabilities and excellent protection for the pipes.

[0030] Among the cleaning agents, sulfamic acid, as the main acidic component, possesses excellent scale-dissolving capabilities. It effectively penetrates and removes scale layers inside condenser heat exchange tubes, especially insoluble scale such as calcium and magnesium scale. During the cleaning process, sulfamic acid not only functions alone but also works synergistically with nitric acid to further enhance the scale-dissolving effect. The addition of nitric acid not only increases the overall acidity of the cleaning agent but also complements sulfamic acid, working together to dissolve and remove scale layers more easily. Simultaneously, at appropriate concentrations, nitric acid can reduce the corrosiveness of the cleaning agent to metals, ensuring the safety and effectiveness of the cleaning process. Glycolic acid, as an organic acid, has excellent chelating ability. It can form stable complexes with metal ions, thereby removing insoluble scale layers. Furthermore, glycolic acid has low corrosiveness and high biodegradability, making the cleaning agent more environmentally friendly and safer. During the cleaning process, glycolic acid not only effectively removes scale layers but also reduces corrosion to stainless steel pipes, protecting the integrity and service life of the pipes. The addition of sodium isoascorbate helps improve the corrosion inhibition performance of the cleaning agent. As an antioxidant, sodium isoascorbate can combine with metal ions to form stable complexes, thereby slowing down the rate of metal corrosion. It is particularly effective in preventing copper plating defects, avoiding unnecessary corrosion losses and further protecting the pipes from damage. Lan-826 corrosion inhibitor is another important corrosion inhibitor. It forms a dense protective film on the metal surface, effectively preventing corrosive components in the cleaning agent from directly contacting the metal. This protective film not only has excellent corrosion resistance but also remains stable during the cleaning process, ensuring the pipes are not damaged by corrosion. Benzotriazole has a dual effect of inhibiting metal corrosion and oxidation. It can form chemical bonds with the metal surface, enhancing the corrosion inhibition effect. During the cleaning process, benzotriazole not only reduces the metal corrosion rate but also prevents metal oxidation, further extending the service life of the pipes. Dimethyl alkyl phosphate, as an auxiliary corrosion inhibitor, plays an important role in the cleaning agent. It not only further enhances the corrosion inhibition effect of the cleaning agent but also reduces foam generated during the cleaning process, improving cleaning efficiency. Meanwhile, dialkyl phosphate also has good biocompatibility and environmental friendliness, ensuring that the cleaning agent will not have a negative impact on the environment during long-term use.

[0031] In summary, this invention successfully solves the technical problem of existing chemical cleaning agents causing corrosion to stainless steel pipes by adding various corrosion inhibitors and descaling agents, selecting cleaning agent components with excellent scale-dissolving capabilities, and rationally controlling their ratios and concentrations. This chemical cleaning agent not only has highly efficient cleaning capabilities but also effectively protects the pipes from damage, extends the service life of the condenser, and improves the safety and economy of the unit.

[0032] The ratio of nitric acid, glycolic acid, and aminosulfonic acid in the raw materials of the above chemical cleaning reagent is 1:2:3, and the ratio of Lan-826 corrosion inhibitor to benzotriazole is 1:2.

[0033] On the one hand, the preparation method of the above-mentioned chemical cleaning reagent for condensers of thermal power plants includes the following steps: by mass percentage, 0.3-3% of aminosulfonic acid, 0.1-1% of nitric acid, 0.2-2% of glycolic acid, 0.02-0.05% of sodium isoascorbate, 0.1-0.2% of Lan-826 corrosion inhibitor, 0.2-0.4% of benzotriazole, and 0.02-0.05% of dialkyl phosphate are added to water to obtain the chemical cleaning reagent for condensers of thermal power plants.

[0034] On the other hand, the aforementioned chemical cleaning reagents for condensers in thermal power plants are used in the condenser cleaning process of thermal power plants.

[0035] When using chemical cleaning agents, the cleaning temperature is 45-55℃, and the cleaning method is circulating cleaning.

[0036] The aforementioned chemical cleaning agents have a descaling rate greater than 98%, ensuring effective cleaning and restoring the condenser's heat exchange efficiency. Furthermore, the corrosion rate is less than 0.05 g / (m²). 2 •h) ensures that the cleaning agent has extremely low corrosiveness to the pipes, protecting them from damage.

[0037] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0038] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0039] Example 1

[0040] This embodiment provides a chemical cleaning system for condensers in thermal power plants, specifically for the condenser of a 300MW thermal power unit.

[0041] The chemical cleaning agent is prepared by weight percentage as follows: 3% aminosulfonic acid, 1% nitric acid, 2% glycolic acid, 0.05% sodium isoascorbate, 0.2% Lan-826 corrosion inhibitor, 0.4% benzotriazole, 0.05% dialkyl phosphate, with the balance being water. The ratio of nitric acid, glycolic acid, and aminosulfonic acid is 1:2:3, and the ratio of Lan-826 corrosion inhibitor to benzotriazole is 1:2. The cleaning temperature is 50℃, the cleaning time is 24 hours, and the pH value is maintained at 3-4.

[0042] Example 2

[0043] This embodiment provides a chemical cleaning system for condensers in thermal power plants, specifically for the condenser of a 600MW thermal power unit.

[0044] The chemical cleaning agent is prepared by weight percentage as follows: 1.5% aminosulfonic acid, 0.5% nitric acid, 1% glycolic acid, 0.05% sodium isoascorbate, 0.1% Lan-826 corrosion inhibitor, 0.2% benzotriazole, 0.05% dialkyl phosphate, with the balance being water. The ratio of nitric acid, glycolic acid, and aminosulfonic acid is 1:2:3, and the ratio of Lan-826 corrosion inhibitor to benzotriazole is 1:2. The cleaning temperature is 50℃, the cleaning time is 24 hours, and the pH value is maintained at 3-4.

[0045] Example 3

[0046] This embodiment provides a chemical cleaning system for condensers in thermal power plants, specifically for the condenser of a 600MW thermal power unit.

[0047] The chemical cleaning agent, by mass percentage, consists of: 0.3% aminosulfonic acid, 0.1% nitric acid, 0.2% glycolic acid, 0.02% sodium isoascorbate, 0.1% Lan-826 corrosion inhibitor, 0.2% benzotriazole, 0.02% dialkyl phosphate, with the balance being water. The ratio of nitric acid, glycolic acid, and aminosulfonic acid is 1:2:3, and the ratio of Lan-826 corrosion inhibitor to benzotriazole is 1:2. The cleaning temperature is 45℃, the cleaning time is 24 hours, and the pH value is maintained at 3-4.

[0048] Example 4

[0049] This embodiment provides a chemical cleaning system for condensers in thermal power plants, specifically for the condenser of a 600MW thermal power unit.

[0050] The chemical cleaning agent, by mass percentage, consists of: 2.7% aminosulfonic acid, 0.9% nitric acid, 1.8% glycolic acid, 0.04% sodium isoascorbate, 0.15% Lan-826 corrosion inhibitor, 0.3% benzotriazole, 0.04% dialkyl phosphate, with the balance being water. The ratio of nitric acid, glycolic acid, and aminosulfonic acid is 1:2:3, and the ratio of Lan-826 corrosion inhibitor to benzotriazole is 1:2. The cleaning temperature is 55℃, the cleaning time is 24 hours, and the pH value is maintained at 3-4.

[0051] Example 5

[0052] This embodiment provides a chemical cleaning reagent for condensers in thermal power plants, used in the condenser of a 600MW thermal power unit.

[0053] The chemical cleaning reagent, by mass percentage, consists of: 2% aminosulfonic acid, 0.67% nitric acid, 1.33% glycolic acid, 0.04% sodium isoascorbate, 0.15% Lan-826 corrosion inhibitor, 0.3% benzotriazole, 0.03% dialkyl phosphate, with the balance being water. The ratio of nitric acid, glycolic acid, and aminosulfonic acid is 1:2:3, and the ratio of Lan-826 corrosion inhibitor to benzotriazole is 1:2. The cleaning temperature is 52℃, the cleaning time is 24 hours, and the pH value is maintained at 3-4.

[0054] Example 6

[0055] This embodiment provides a chemical cleaning reagent for condensers in thermal power plants, used in the condenser of a 600MW thermal power unit.

[0056] The chemical cleaning reagent, by mass percentage, consists of: 0.5% aminosulfonic acid, 0.17% nitric acid, 0.33% glycolic acid, 0.03% sodium isoascorbate, 0.12% Lan-826 corrosion inhibitor, 0.24% benzotriazole, 0.025% dialkyl phosphate, with the balance being water. The ratio of nitric acid, glycolic acid, and aminosulfonic acid is 1:2:3, and the ratio of Lan-826 corrosion inhibitor to benzotriazole is 1:2. The cleaning temperature is 48℃, the cleaning time is 24 hours, and the pH value is maintained at 3-4.

[0057] Example 7

[0058] This embodiment provides a chemical cleaning reagent for condensers in thermal power plants, used in the condenser of a 300MW thermal power unit.

[0059] The chemical cleaning reagent, by mass percentage, consists of: 1% aminosulfonic acid, 0.33% nitric acid, 0.67% glycolic acid, 0.025% sodium isoascorbate, 0.1% Lan-826 corrosion inhibitor, 0.2% benzotriazole, 0.045% dialkyl phosphate, with the balance being water. The ratio of nitric acid, glycolic acid, and aminosulfonic acid is 1:2:3, and the ratio of Lan-826 corrosion inhibitor to benzotriazole is 1:2. The cleaning temperature is 50℃, the cleaning time is 24 hours, and the pH value is maintained at 3-4.

[0060] Example 8

[0061] This embodiment provides a chemical cleaning reagent for condensers in thermal power plants, used in the condenser of a 400MW thermal power unit.

[0062] The chemical cleaning reagent, by mass percentage, consists of: 2.5% aminosulfonic acid, 0.83% nitric acid, 1.67% glycolic acid, 0.05% sodium isoascorbate, 0.18% Lan-826 corrosion inhibitor, 0.36% benzotriazole, 0.03% dialkyl phosphate, with the balance being water. The ratio of nitric acid, glycolic acid, and aminosulfonic acid is 1:2:3, and the ratio of Lan-826 corrosion inhibitor to benzotriazole is 1:2. The cleaning temperature is 54℃, the cleaning time is 24 hours, and the pH value is maintained at 3-4.

[0063] Example 9

[0064] This embodiment provides a chemical cleaning reagent for condensers in thermal power plants, used in the condenser of a 600MW thermal power unit.

[0065] The chemical cleaning reagent, by mass percentage, consists of: 0.8% aminosulfonic acid, 0.27% nitric acid, 0.54% glycolic acid, 0.035% sodium isoascorbate, 0.14% Lan-826 corrosion inhibitor, 0.28% benzotriazole, 0.02% dialkyl phosphate, with the balance being water. The ratio of nitric acid, glycolic acid, and aminosulfonic acid is 1:2:3, and the ratio of Lan-826 corrosion inhibitor to benzotriazole is 1:2. The cleaning temperature is 47℃, the cleaning time is 24 hours, and the pH value is maintained at 3-4.

[0066] Example 10

[0067] This embodiment provides a chemical cleaning reagent for condensers in thermal power plants, used in the condenser of a 500MW thermal power unit.

[0068] The chemical cleaning reagent, by mass percentage, consists of: 1.2% aminosulfonic acid, 0.4% nitric acid, 0.8% glycolic acid, 0.045% sodium isoascorbate, 0.16% Lan-826 corrosion inhibitor, 0.32% benzotriazole, 0.04% dialkyl phosphate, with the balance being water. The ratio of nitric acid, glycolic acid, and aminosulfonic acid is 1:2:3, and the ratio of Lan-826 corrosion inhibitor to benzotriazole is 1:2. The cleaning temperature is 51℃, the cleaning time is 24 hours, and the pH value is maintained at 3-4.

[0069] Comparative Example 1

[0070] This comparative example is basically the same as Example 1. The chemical cleaning agent is prepared by mass percentage as follows: 3% aminosulfonic acid, 0.05% sodium isoascorbate, 0.2% Lan-826 corrosion inhibitor, 0.4% benzotriazole, 0.05% dialkyl phosphate, and the balance is water. The cleaning is carried out at 50°C for 24 hours.

[0071] Compared with Example 1, Comparative Example 1 only used aminosulfonic acid for cleaning, while other aspects remained unchanged. The descaling rate was significantly lower than that of cleaning with nitric acid, glycolic acid, and aminosulfonic acid.

[0072] Comparative Example 2

[0073] This comparative example is basically the same as Example 1. The chemical cleaning agent is prepared by mass percentage as follows: 3% glycolic acid, 0.05% sodium isoascorbate, 0.2% Lan-826 corrosion inhibitor, 0.4% benzotriazole, 0.05% dialkyl phosphate, and the balance is water. The cleaning is carried out at 50°C for 24 hours.

[0074] Compared with Example 1, Comparative Example 2 only used glycolic acid for cleaning, while other aspects remained unchanged. The descaling rate was significantly lower than that of cleaning with nitric acid, glycolic acid, and aminosulfonic acid.

[0075] Comparative Example 3

[0076] This comparative example is basically the same as Example 1. The chemical cleaning agent is prepared by mass percentage as follows: 3% aminosulfonic acid, 0.05% sodium isoascorbate, 0.2% Lan-826 corrosion inhibitor, 0.05% dialkyl phosphate, and the balance is water. The cleaning is carried out at 50°C for 24 hours.

[0077] Compared with Example 1, Comparative Example 3 removed glycolic acid and nitric acid, as well as benzotriazole corrosion inhibitor. The descaling rate was significantly lower than that of cleaning with nitric acid, glycolic acid, and aminosulfonic acid, and the corrosion rate increased.

[0078] Comparative Example 4

[0079] This comparative example is basically the same as Example 1. The chemical cleaning agent is prepared by mass percentage as follows: 3% aminosulfonic acid, 2% glycolic acid, 1% nitric acid, 0.05% sodium isoascorbate, 0.2% Lan-826 corrosion inhibitor, 0.05% dialkyl phosphate, and the balance is water. The cleaning is carried out at 50°C for 24 hours.

[0080] Compared with Example 1, Comparative Example 4 removed the benzotriazole corrosion inhibitor, resulting in a significantly increased corrosion rate.

[0081] test:

[0082] Before cleaning, test pieces made of the same material as the condenser tubes were suspended in the water chamber to determine the corrosion rate.

[0083] The following methods were used to test the descaling rate and corrosion rate of the examples and comparative examples, respectively.

[0084] Descaling rate is calculated using the formula Calculate, where G0 represents the descaling rate, G1 represents the original scale amount of the tube sample, and G1 represents the residual scale amount of the tube sample.

[0085] Corrosion rate according to formula The calculation is performed, where V is the corrosion rate, m0 is the mass of the specimen before the experiment, m1 is the mass of the specimen after the experiment, S is the surface area of ​​the specimen, and t is the reaction time.

[0086] The testing methods for descaling rate and corrosion rate shall be carried out in accordance with the Boiler Chemical Cleaning Guidelines DL / T794.

[0087]

[0088] This invention provides a chemical cleaning agent for condensers in thermal power plants. The main cleaning agents, nitric acid, glycolic acid, and aminosulfonic acid, have good solubility and are suitable for cleaning calcium and magnesium scale in condensers. It exhibits strong descaling ability at temperatures of 45-55℃, achieving a descaling rate of over 98%. Furthermore, the combination of corrosion inhibitor Lan826 and benzotriazole can achieve a very low corrosion rate for heat exchange tubes, less than 0.05 g / (m²). 2 As can be seen from the above, the present invention provides a chemical cleaning agent for condensers in thermal power plants, which has a cleaning effect far superior to that of single cleaning agents and is suitable for removing calcium and magnesium scale and other corrosion products from condensers in thermal power plants.

[0089] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A chemical cleaning agent for condensers in thermal power plants, characterized in that, The chemical cleaning reagent comprises, by mass percentage, 0.3-3% aminosulfonic acid, 0.1-1% nitric acid, 0.2-2% glycolic acid, 0.02-0.05% sodium isoascorbate, 0.1-0.2% Lan-826 corrosion inhibitor, 0.2-0.4% benzotriazole, 0.02-0.05% dialkyl phosphate, with the balance being water. When preparing the chemical cleaning reagent, the ratio of nitric acid, glycolic acid, and aminosulfonic acid is 1:2:3; the ratio of Lan-826 corrosion inhibitor to benzotriazole is 1:

2.

2. The chemical cleaning reagent for condensers in thermal power plants according to claim 1, characterized in that, The pH value of the chemical cleaning agent is maintained at 3-4.

3. A method for preparing a chemical cleaning reagent for condensers in thermal power plants according to any one of claims 1 to 2, characterized in that, Includes the following steps: A chemical cleaning reagent for condensers in thermal power plants was prepared by sequentially adding aminosulfonic acid, nitric acid, glycolic acid, sodium isoascorbate, Lan-826 corrosion inhibitor, benzotriazole, and dialkyl phosphate to water.

4. The application of a chemical cleaning agent for condensers in thermal power plants as described in any one of claims 1 to 2 in the condenser cleaning process of thermal power plants.

5. The application of the chemical cleaning reagent for condensers in thermal power plants according to claim 4 in the condenser cleaning process of thermal power plants, characterized in that, The cleaning temperature when using the chemical cleaning reagent is 45-55℃.

6. The application of the chemical cleaning reagent for condensers in thermal power plants according to claim 4 in the condenser cleaning process of thermal power plants, characterized in that, The chemical cleaning reagent is used for cyclic cleaning.

7. The application of the chemical cleaning reagent for condensers in thermal power plants according to claim 4 in the condenser cleaning process of thermal power plants, characterized in that, The chemical cleaning agent has a descaling rate of greater than 98%.

8. The application of the chemical cleaning reagent for condensers in thermal power plants according to claim 4 in the condenser cleaning process of thermal power plants, characterized in that, The corrosion rate of the chemical cleaning agent is less than 0.05 g / (m²). 2 ·h).

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