Oil sludge cleaning agent for steam turbine speed regulating system and preparation method of oil sludge cleaning agent

Abstract

The invention relates to the technical field of chemistry and chemical engineering technologies, in particular to a steam turbine speed regulating system oil sludge cleaning agent and a preparation method thereof. Comprising phosphate base oil, a surfactant, a dispersing agent and a clearing agent, wherein the phosphate base oil comprises one or three of trimethyl phosphate, di-tert-butyl-phenyl phosphate and tri (xylene) phosphate; the oil sludge cleaning agent can efficiently and rapidly remove oil sludge attached to the speed regulating system, has good compatibility with a sealing material used in the speed regulating system, and solves the problems that cleaning is not thorough, the cost is high, the environment is polluted when operating oil is used, and a conventional cleaning agent cannot be used.

Description

Technical Field

[0001] The present invention relates to the technical field of chemistry and chemical engineering technology, and specifically to an oil sludge cleaning agent for a steam turbine speed regulating system and a preparation method thereof. Background Art

[0002] Phosphate ester fire-resistant oil, as a highly specialized fully synthetic flame-retardant hydraulic fluid, plays an important role in the turbine speed control system of modern power plants with its excellent flame retardancy, good oxidation stability and excellent lubrication performance. This type of hydraulic fluid is designed to provide stable and reliable speed control under extreme working conditions, such as high temperature, high pressure and potential fire risk environments. It can not only effectively reduce the risk of downtime caused by hydraulic system failure, but also significantly improve power generation efficiency and safety.

[0003] However, despite the many advantages of phosphate fire-resistant oils, their chemical stability will still be challenged by many factors during long-term use. First, high temperature environment will accelerate the oxidation process of oil products, causing molecular chain breakage and generating a series of acidic byproducts. These acidic substances will not only corrode metal parts in the system, but also promote the formation of colloid and sludge, further affecting the normal operation of the system. Secondly, moisture is another influencing factor that cannot be ignored. It can enter the oil through penetration and react with phosphate molecules to hydrolyze, which also promotes the deterioration of oil products. Furthermore, the presence of metal catalysts, such as trace elements such as iron and copper, will catalyze the oxidation and decomposition of oil products, further increasing the rate of oil deterioration.

[0004] The speed control system, especially its core servo valve assembly, has extremely high requirements for the cleanliness of the oil. The clearance between the valve sleeve and the valve core inside the servo valve is extremely small, usually only a few microns to tens of microns. Any tiny impurity deposition may cause the valve core to become stuck, slow to move, or completely fail, directly threatening the stable operation of the steam turbine. In severe cases, it may even lead to "unplanned shutdown" (i.e. "non-stop") accidents, causing huge economic losses and safety hazards to the power plant.

[0005] Regarding the cleaning and maintenance of the speed control system, the traditional hot oil circulation cleaning method can alleviate the problem of sludge accumulation to a certain extent, but its limitations are also very obvious. On the one hand, hot oil circulation mainly relies on the dissolution and flushing ability of the system operating oil itself, and the cleaning efficiency is low for stubborn sludge and sediments, and it is difficult to achieve a thorough cleaning effect; on the other hand, the oil at high temperature may accelerate the further oxidation of the remaining oil, which in turn aggravates the overall deterioration process of the oil.

[0006] In addition, the unique physical and chemical properties of phosphate ester fire-resistant oils also bring additional challenges to cleaning. Compared with traditional mineral oils, phosphate ester fire-resistant oils have higher polarity, lower flash point and different chemical activity, which means that they have special requirements for the compatibility of sealing materials. Most cleaning agents designed for mineral oils on the market cannot effectively remove the sludge in phosphate ester fire-resistant oils due to differences in composition and potential chemical reaction risks. They may also damage the system seals and cause secondary failures such as oil leaks.

[0007] In summary, developing an efficient, safe, and specialized solution for cleaning phosphate ester fire-resistant oil sludge is of great significance for ensuring the stable operation of the turbine speed control system of power plants, extending equipment life, and reducing maintenance costs. This requires not only that the cleaning agent has excellent solubility and compatibility with phosphate ester fire-resistant oil, but also that it is harmless to system materials to ensure that the cleaning process does not cause secondary pollution or damage to the system. Summary of the invention

[0008] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a turbine speed control system sludge cleaning agent and a preparation method thereof, which can efficiently and quickly remove the sludge attached to the speed control system, has good compatibility with the sealing materials used in the speed control system, and solves the problems of incomplete cleaning, high cost and environmental pollution when using operating oil, and the inability to use conventional cleaning agents.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a steam turbine speed control system sludge cleaning agent, comprising a phosphate ester base oil, a surfactant, a dispersant and a detergent, wherein the phosphate ester base oil comprises one or three of trimethyl phosphate, di-tert-butyl-phenyl phosphate and tri(xylene) phosphate.

[0010] Preferably, the surfactant includes one or more of polyol polyoxypropylene ether, sodium dodecyl sulfate and alkylbenzene sulfonic acid.

[0011] Preferably, the dispersant includes one or both of 3-aminopropane sulfonate and bis-succinimide.

[0012] Preferably, the detergent is one or both of disodium ethylenediaminetetraacetate and polyisobutylene succinimide.

[0013] Preferably, the weight of the surfactant accounts for 5% to 10% of the weight of the phosphate base oil.

[0014] Preferably, the weight of the dispersant accounts for 3% to 10% of the weight of the phosphate base oil.

[0015] Preferably, the weight of the detergent accounts for 2% to 8% of the weight of the phosphate base oil.

[0016] In a second aspect, the present invention provides a method for preparing a sludge cleaning agent for a steam turbine speed control system, comprising the following steps: The dispersant and detergent are mixed, and after the first stirring, the phosphate base oil is added, after the second stirring, the surfactant is added, and after heating, the third stirring is performed to obtain the sludge cleaning agent for the turbine speed control system.

[0017] Preferably, the first stirring time is 30 to 60 minutes; the second stirring time is not less than 40 minutes; and the third stirring time is not less than 1 hour.

[0018] Preferably, the heating temperature is 45-55°C.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The anions such as sulfonic acid groups in the surfactant in the steam turbine speed control system cleaning agent of the present invention can interact with the sludge molecules attached to the inside of the pipes and valves to fully dissolve them. The dispersant and detergent can disperse the dissolved sludge well in the base oil, so that the sludge is finally discharged from the system with the cleaning agent, thereby achieving the purpose of thoroughly cleaning the sludge in the system. The sludge cleaning agent of the present invention can efficiently and quickly remove the sludge attached to the metal surface of the speed control system, avoid oil pollution after replacing new oil, thereby improving the safety and economy of the operation of the power plant speed control system; the synthesis method of the present invention is simple and low in cost, suitable for large-scale production, and suitable for cleaning sludge in the steam turbine speed control system of a power plant or other hydraulic control systems using phosphate fire-resistant oils. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0021] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0022] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0023] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0024] The first object of the present invention is to provide a steam turbine speed control system sludge cleaning agent, comprising a phosphate ester base oil, a surfactant, a dispersant and a detergent; the phosphate ester base oil, as the main carrier of the cleaning agent, not only has excellent lubrication performance, but also can provide a stable solvent environment during the cleaning process, and its good solubility and permeability help other active ingredients to better penetrate into the sludge and dirt, accelerating their decomposition and peeling; the surfactant can significantly reduce the surface tension of the oil-water interface, making the sludge easier to be wetted and dispersed by water or other solvents; the dispersant is mainly used to prevent the sludge particles peeled off during the cleaning process from being redeposited on the equipment surface, so as to maintain the cleanliness of the cleaning liquid.

[0025] The phosphate base oil includes one or three of trimethyl phosphate, di-tert-butyl-phenyl phosphate and tri(xylene) phosphate. Trimethyl phosphate is an organic phosphate compound, usually a colorless transparent liquid, with a low melting point and a high boiling point, and is volatile. In phosphate ester fire-resistant oils, trimethyl phosphate can significantly improve the flame retardancy of the fuel when used in combination with other flame retardants. Di-tert-butyl-phenyl phosphate is an organic phosphate compound with high thermal stability and chemical stability. In phosphate ester fire-resistant oils, it is often used as a high-temperature fire-resistant hydraulic oil, and is particularly suitable for hydraulic systems that require high heat resistance and stability; its high thermal stability and chemical stability enable it to maintain good fire resistance in high temperature environments, and it is an important component of high-temperature fire-resistant hydraulic oil. Tri(xylene) phosphate, also known as trixylenol phosphate, is a common component in phosphate ester fire-resistant oils. It usually exists in the form of a mixture, contains multiple isomers, and has excellent flame retardant properties and chemical stability; it has excellent flame retardant properties, can significantly reduce the ignition point of fuel, inhibit the spread of flames, and improve the safety of fuel.

[0026] The surfactant includes one or more of polyol polyoxypropylene ether, sodium dodecyl sulfonate and alkylbenzene sulfonic acid. Polyol polyoxypropylene ether is a nonionic surfactant, and its chemical structure is formed by alternating polyoxyethylene and polyoxypropylene groups, which gives it unique hydrophilicity and lipophilicity, and can be mixed with water and other organic solvents. Sodium dodecyl sulfonate is an anionic surfactant, which is formed by combining a benzene sulfonic acid group with a dodecyl chain. It is usually a white or light yellow powder or flaky solid, which is difficult to volatilize but soluble in water to form a translucent solution. Alkylbenzene sulfonic acid and its salts have excellent surface activity, can significantly reduce the surface tension of the solution, and improve the effects of washing, emulsification, dispersion, etc. The three each have different lipophilic groups and hydrophilic groups, which can work synergistically to enhance the ability to wrap, disperse and suspend sludge, thereby improving the cleaning effect.

[0027] The dispersant includes one or two of 3-aminopropane sulfonate and bis-succinimide. Both can be adsorbed on the surface of sludge particles to form a protective film to prevent aggregation and sedimentation between particles. At the same time, they can also promote the uniform distribution of sludge particles in the cleaning liquid, further improving the cleaning efficiency. 3-aminopropane sulfonic acid, as a zwitterionic surfactant, has excellent decontamination, antistatic, and hydrophilic abilities, can effectively reduce surface tension, and promote uniform dispersion of substances. Disuccinimide is composed of a lipophilic group (hydrocarbon group), a polar group, and a connecting group, so that it can interact with the oil phase and the solid particles or colloids to be dispersed at the same time. The oil-soluble groups provided by bis-succinimide can effectively prevent the polymerization of carbon deposits and colloids, forming a three-dimensional barrier film to prevent them from aggregating with each other; at the same time, its ionization polarity is also large, which can attract and disperse the peptized particles in the oil, so that larger particles are dispersed in the oil.

[0028] The detergent is one or both of disodium ethylenediaminetetraacetate (EDTA) and polyisobutylene succinimide (PIBA). Not only can they effectively neutralize acidic residues, but they can also form a protective film with the metal surface to prevent further corrosion. In addition, they also have a certain cleaning effect and can further remove stubborn stains and oil films on the surface of equipment. EDTA can enhance the cleaning power and emulsifying power, prevent precipitation, and improve the washing effect. PIBA is prepared from highly active polyisobutylene, has good cleaning and dispersibility, and can inhibit the formation of carbon deposits and paint films on engine pistons.

[0029] The weight of the surfactant accounts for 5% to 10% of the weight of the phosphate base oil. This ratio can ensure that a sufficient number of molecules cover the surface of the sludge, reduce surface tension, make the sludge easier to be wetted and dispersed by the cleaning fluid, and help the sludge particles to be peeled off from the surface of the equipment and suspended in the cleaning fluid to prevent re-deposition. Too high a surfactant ratio will increase costs and will not significantly improve the cleaning effect; while too low a ratio will lead to insufficient wetting and dispersion capabilities, affecting the cleaning effect.

[0030] The weight of the dispersant accounts for 3% to 10% of the weight of the phosphate base oil. This ratio can ensure that there are enough dispersant molecules adsorbed on the surface of the sludge particles to form a stable protective layer, prevent aggregation and sedimentation between particles, help maintain the cleanliness of the cleaning fluid, and improve cleaning efficiency. The right amount of dispersant can also promote the uniform distribution of sludge particles in the cleaning fluid, so that the cleaning fluid can more comprehensively contact and clean the equipment surface, further improving the cleaning performance.

[0031] The weight of the detergent accounts for 2-8% of the weight of the phosphate base oil. This ratio can effectively neutralize the acidic residues generated during the cleaning process and prevent corrosion to the equipment, which is of great significance for protecting the equipment surface and extending the service life of the equipment. The detergent can also work synergistically with surfactants, dispersants and other ingredients to jointly improve the cleaning effect. For example, the detergent can remove stubborn stains and oil films on the surface of the equipment, providing a better working environment for surfactants and dispersants.

[0032] The second object of the present invention is to provide a method for preparing a steam turbine speed control system sludge cleaning agent, comprising the following steps: The dispersant and detergent are mixed, stirred for 30-60 minutes, then the phosphate base oil is added, and stirring is continued for not less than 40 minutes. A surfactant is added, and after heating to 45-55°C, stirring is continued for not less than 1 hour to obtain the sludge cleaning agent for the turbine speed control system.

[0033] First, the dispersant and detergent are mixed and stirred to ensure that the two additives can be more evenly dispersed in the phosphate ester base oil in the subsequent steps, which helps them to play a more stable and consistent role in the cleaning process. The good solubility of the phosphate ester base oil can ensure that the dispersant and detergent are fully dissolved and dispersed in it, so as to play a better role. When the temperature is raised to 45~55℃, the activity of the surfactant can be maximized, which helps the surfactant to penetrate into the sludge and dirt more effectively and accelerate its decomposition and stripping. Continuing to stir for no less than 1h can ensure that the surfactant is fully mixed and reacted with the previous mixture, which helps to form a uniform detergent system and further improve its cleaning effect. The role of the surfactant is fully exerted in this process, which can significantly reduce the surface tension of the oil-water interface and enhance the ability to wrap, disperse and suspend the sludge. At the same time, the synergistic effect with other components also improves the overall performance of the detergent.

[0034] Example 1 Mix 3 g of 3-aminopropane sulfonate and 2 g of disodium ethylenediaminetetraacetate, stir for 30 min, add 100 g of trimethyl phosphate, continue stirring for 40 min, add 5 g of polyol polyoxypropylene ether, heat to 45°C, continue stirring for 1 h to obtain a turbine speed control system sludge cleaning agent.

[0035] Performance test: The turbine speed control system sludge cleaning agent prepared in this embodiment was used to circulate and flush the speed control system of a 1000MW unit in a thermal power plant in Shandong at room temperature for 3 hours, then discharged and injected with new oil. After the unit ran for 168 hours, the phosphate anti-oil in the speed control system was tested for "sludge precipitation" according to DL / T 429.7-2017 "Determination Method for Sludge Precipitation of Power Oil", and the result was "none".

[0036] Example 2 Mix 5 g of bis(succinimide) and 4 g of polyisobutylene succinimide, stir for 40 min, add 100 g of di-tert-butyl-phenyl phosphate, continue stirring for 40 min, add 6 g of sodium dodecyl sulfate, heat to 48° C., continue stirring for 1 h to obtain a turbine speed control system sludge cleaning agent.

[0037] Performance test: The turbine speed control system sludge cleaning agent prepared in this embodiment was used to circulate and flush the speed control system of a 300MW unit in a thermal power plant in Lanzhou at room temperature for 2 hours, then discharged and injected with new oil. After the unit ran for 168 hours, the phosphate anti-oil in the speed control system was tested for "sludge precipitation" according to DL / T 429.7-2017 "Determination Method for Sludge Precipitation of Power Oil", and the result was "none".

[0038] Example 3 A total of 7 g of 3-aminopropane sulfonate and bis-succinimide were mixed with a total of 5 g of disodium ethylenediaminetetraacetate and polyisobutylene succinimide, and stirred for 45 minutes, followed by the addition of 100 g of tri(xylene) phosphate, and continued stirring for 45 minutes. Then, 7 g of alkylbenzene sulfonic acid was added, and the temperature was raised to 50°C, and continued stirring for 1.5 hours to obtain a sludge cleaning agent for a turbine speed control system.

[0039] Performance test: The turbine speed control system sludge cleaning agent prepared in this embodiment was used to circulate and flush the speed control system of a 1000MW unit in a thermal power plant in Henan Province at room temperature for 2 hours, then discharged and injected with new oil. After the unit was operated for 168 hours, the phosphate anti-oil in the speed control system was tested for "sludge precipitation" according to DL / T 429.7-2017 "Determination Method for Sludge Precipitation of Power Oil", and the result was "none".

[0040] Example 4 A total of 9 g of 3-aminopropane sulfonate and disodium ethylenediaminetetraacetate were mixed with 6 g of polyisobutylene succinimide, and stirred for 50 min. A total of 100 g of trimethyl phosphate, di-tert-butyl-phenyl phosphate and tri(xylene) phosphate were added, and stirring was continued for 45 min. A total of 9 g of polyol polyoxypropylene ether and sodium dodecyl sulfonate were added, and the temperature was raised to 52°C. Stirring was continued for 2 h to obtain a sludge cleaning agent for a turbine speed control system.

[0041] Performance test: The turbine speed control system sludge cleaning agent prepared in this embodiment was used to circulate and flush the speed control system of a 600MW unit of a thermal power plant in Inner Mongolia at room temperature for 3.5 hours, then discharged and injected with new oil. After the unit ran for 168 hours, the phosphate anti-oil in the speed control system was tested for "sludge precipitation" according to DL / T 429.7-2017 "Determination Method for Sludge Precipitation of Power Oil", and the result was "none".

[0042] Example 5 Mix 10 g of 3-aminopropane sulfonate and 8 g of disodium ethylenediaminetetraacetate, stir for 60 min, add 100 g of trimethyl phosphate, continue stirring for 50 min, add a total of 10 g of polyol polyoxypropylene ether, sodium dodecyl sulfonate and alkylbenzene sulfonic acid, heat to 55°C, continue stirring for 3 h to obtain a turbine speed control system sludge cleaning agent.

[0043] Performance test: The turbine speed control system sludge cleaning agent prepared in this embodiment was used to circulate and flush the speed control system of a 600MW unit in a thermal power plant in Shaanxi at room temperature for 3 hours, then discharged and injected with new oil. After the unit ran for 168 hours, the phosphate anti-oil in the speed control system was tested for "sludge precipitation" according to DL / T 429.7-2017 "Determination Method for Sludge Precipitation of Power Oil", and the result was "none".

[0044] According to the performance test results of Examples 1-5, the cleaning agent finally obtained can efficiently and quickly remove the sludge and dirt in the turbine speed control system. The present invention not only improves the stability and cleaning effect of the cleaning agent, but also protects the equipment from corrosion and wear, and prolongs the service life of the equipment. In addition, since each component is an environmentally friendly material and no harmful by-products are produced during the preparation process, the cleaning agent also has good environmental performance. In summary, the turbine speed control system sludge cleaning agent prepared in this embodiment shows excellent cleaning effect, durability and safety in practical applications, and is an effective tool to ensure the stable operation of the turbine speed control system of a power plant.

[0045] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A steam turbine speed control system sludge cleaning agent, characterized in that: The invention comprises a phosphate ester base oil, a surfactant, a dispersant and a detergent. The phosphate ester base oil comprises one or three of trimethyl phosphate, di-tert-butyl-phenyl phosphate and tri(xylene) phosphate.

2. The steam turbine speed control system sludge cleaning agent according to claim 1, characterized in that: The surfactant includes one or more of polyol polyoxypropylene ether, sodium dodecyl sulfonate and alkylbenzene sulfonic acid.

3. The steam turbine speed control system sludge cleaning agent according to claim 1, characterized in that: The dispersant includes one or both of 3-aminopropane sulfonate and bis-succinimide.

4. The steam turbine speed control system sludge cleaning agent according to claim 1, characterized in that: The detergent is one or both of disodium ethylenediaminetetraacetate and polyisobutylene succinimide.

5. The steam turbine speed control system sludge cleaning agent according to claim 1, characterized in that: The weight of the surfactant accounts for 5% to 10% of the weight of the phosphate base oil.

6. The steam turbine speed control system sludge cleaning agent according to claim 1, characterized in that: The weight of the dispersant accounts for 3% to 10% of the weight of the phosphate base oil.

7. The steam turbine speed control system sludge cleaning agent according to claim 1, characterized in that: The weight of the detergent accounts for 2% to 8% of the weight of the phosphate base oil.

8. The method for preparing a steam turbine speed control system sludge cleaning agent according to claim 1, characterized in that: The following steps are involved: The dispersant and detergent are mixed, and after the first stirring, the phosphate base oil is added, after the second stirring, the surfactant is added, and after heating, the third stirring is performed to obtain the sludge cleaning agent for the turbine speed control system.

9. The method for preparing a steam turbine speed control system sludge cleaning agent according to claim 8, characterized in that: The first stirring time is 30~60min; the second stirring time is not less than 40min; the third stirring time is not less than 1h.

10. The method for preparing a steam turbine speed control system sludge cleaning agent according to claim 8, characterized in that: The heating temperature is raised to 45-55°C.