Phosphite-based composite additive, high-stability phosphate fire-resistant oil and application

Abstract

The invention provides a phosphite-based composite additive and high-stability phosphate fire-resistant oil and application thereof, and the phosphite-based composite additive is a mixture of bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, 2, 6-butylated hydroxytoluene and Revonox 501, and the mixture is a mixture of 2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, 2, 6-butylated hydroxytoluene and Revonox 501. After the phosphite-based composite additive is added into the phosphate fire-resistant oil, the oxidation resistance and hydrolysis resistance of the phosphate fire-resistant oil can be improved at the same time, the stability of a phosphate fire-resistant oil product is enhanced, and a guarantee is provided for safe operation of a generator set.

Description

Technical Field

[0001] The invention belongs to the technical field of phosphate fire-resistant oil, and in particular to a phosphite-based composite additive and a high-stability phosphate fire-resistant oil and applications thereof. Background Art

[0002] As a fully synthetic phosphate ester flame-retardant hydraulic fluid, phosphate ester fire-resistant oil plays an important role in the speed control system of steam turbines and gas turbines due to its excellent fire retardant and lubricating properties. Its unique triaryl phosphate component gives it these unique properties, but it is also this component characteristic that makes phosphate ester fire-resistant oil face a series of challenges during use.

[0003] Since phosphate ester fire-resistant oil is a chemically synthesized product, its molecular structure is relatively complex and its compatibility with most additives is poor. Therefore, if no additives are added, phosphate ester fire-resistant oil will deteriorate rapidly during use. The specific manifestations are:

[0004] Increased acid value: Under the action of oxygen, heat and moisture, phosphate fire-resistant oils are prone to oxidation and hydrolysis reactions, generating acidic polar substances, which causes the acid value of the oil to continue to increase.

[0005] Resistivity decreases: As the acid value increases, the electrical properties of the oil will also be affected, and the resistivity will gradually decrease, affecting the insulation performance of electrical equipment.

[0006] Oil sludge generation: As the oxidation reaction and hydrolysis reaction continue to deepen, the reaction products will further condense to form oil sludge. The accumulation of oil sludge will block the oil circuit and affect the normal operation of the speed control system.

[0007] Although adding additives can improve the performance of phosphate ester fire-resistant oils to a certain extent, the existing additive solutions still have many problems:

[0008] Limited types of additives: Due to the poor compatibility between phosphate ester fire-resistant oils and additives, most additives cannot be directly applied to phosphate ester fire-resistant oils, resulting in very limited types of optional additives.

[0009] The effect of additives is not significant: Even if additives can be added to phosphate ester fire-resistant oils, their effects are often not significant enough to fundamentally solve problems such as rapid oil deterioration, increased acid value, reduced resistivity and sludge generation.

[0010] During use, the deterioration of oil and the generation of sludge will clog the oil circuit, causing the turbine parts to move inflexibly and affecting the normal operation of the unit; the accumulation of acidic substances will corrode the servo valve and other components of the speed control system, causing jamming, and in severe cases even causing abnormal shutdown of the unit; frequent oil changes and expensive additive costs increase the economic cost of the power industry; the replaced phosphate fire-resistant oil is a general hazardous waste, which will pollute water and soil and cause harm to the environment if not disposed of properly. Summary of the invention

[0011] In order to overcome the problems of the prior art, the present invention provides a phosphite-based composite additive and a high-stability phosphate fire-resistant oil and application thereof, wherein the phosphite-based composite additive is a mixture of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol and Revonox 501. After the phosphite-based composite additive is added to the phosphate fire-resistant oil, the oxidation resistance and hydrolysis resistance of the phosphate fire-resistant oil can be improved at the same time, the stability of the phosphate fire-resistant oil product can be enhanced, and the safe operation of the generator set can be guaranteed.

[0012] To achieve the above object, the present invention provides the following technical solution: a phosphite-based composite additive, wherein the composite additive is a mixture of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol and Revonox 501.

[0013] Furthermore, based on weight fraction, the additive amount of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite accounts for 0.0020% to 0.0100% of the phosphate fire-resistant oil, the additive amount of 2,6-di-tert-butyl-p-cresol accounts for 0.01% to 0.10% of the phosphate fire-resistant oil, and the additive amount of Revonox 501 accounts for 0.0020% to 0.0050% of the phosphate fire-resistant oil.

[0014] Furthermore, the main component of the phosphate fire-resistant oil is trixylene phosphate.

[0015] The present invention also provides a high-stability phosphate fire-resistant oil. A phosphite-based composite additive is added to the phosphate fire-resistant oil. The composite additive is a mixture of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol and Revonox 501.

[0016] Furthermore, the additive amount of the phosphite-based composite additive in the phosphate fire-resistant oil is specifically as follows: the additive amount of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite accounts for 0.0020% to 0.0100% of the phosphate fire-resistant oil, the additive amount of 2,6-di-tert-butyl-p-cresol accounts for 0.01% to 0.10% of the phosphate fire-resistant oil, and the additive amount of Revonox 501 accounts for 0.0020% to 0.0050% of the phosphate fire-resistant oil.

[0017] Furthermore, the main component of the phosphate fire-resistant oil is trixylene phosphate.

[0018] The present invention also provides a method for preparing a high-stability phosphate fire-resistant oil, the specific steps of which are as follows:

[0019] S1: determining the dosage of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol and Revonox 501 according to the total amount of oil products, dissolving bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol and Revonox 501 in new phosphate fire-resistant oil to obtain a phosphite-based composite additive mother liquid;

[0020] In the S2 sealed state, the composite additive mother liquid is added into the phosphate ester fire-resistant oil.

[0021] Further, in S1, at 60°C±5°C, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol and Revonox 501 are dissolved in a new phosphate fire-resistant oil having an amount of 10,000 times the weight of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite in a sealed state to obtain a phosphite-based composite additive mother liquor.

[0022] The invention also provides an application of a high-stability phosphate fire-resistant oil in a turbine speed regulating system of a power plant.

[0023] The invention also provides an application of a high-stability phosphate fire-resistant oil in a gas turbine speed regulating system of a power plant.

[0024] Compared with the prior art, the present invention has at least the following beneficial effects:

[0025] The present invention provides a phosphite-based composite additive, specifically a mixture of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol and Revonox 501, which exhibit a significant synergistic effect. This synergistic effect enhances the performance of each additive, thereby improving the various properties of phosphate ester fire-resistant oil as a whole. The phosphite-based composite additive of the present invention can not only improve the oxidation stability of the phosphate ester fire-resistant oil, but also enhance its hydrolysis stability. This means that under various working conditions, the fire-resistant oil can maintain good performance stability. The amount of the phosphite-based composite additive of the present invention is very small, but the effect is significant, so that the overall cost is relatively low, and efficient performance improvement is achieved at the same time.

[0026] The present invention provides a high-stability phosphate fire-resistant oil. After adding a phosphite-based composite additive, the antioxidant ability and the hydrolysis resistance are both improved, which means that the fire-resistant oil can maintain its performance for a longer time during use, reducing the maintenance and replacement costs caused by performance degradation. By reducing the speed of acid value increase and resistivity decrease, and extending the operating time before sludge is generated, the present invention significantly extends the service life of the phosphate fire-resistant oil. This is particularly important for large-scale equipment (such as power plant steam turbines and gas turbines) that require long-term stable operation. The stable operation of the phosphate fire-resistant oil is directly related to the reliability and safety of the equipment (such as the speed control system). Using the high-stability phosphate fire-resistant oil of the present invention can improve the overall operating reliability of the equipment and reduce the failure and downtime caused by oil problems.

[0027] During the preparation process of the high-stability phosphate fire-resistant oil of the present invention, only an appropriate amount of additives need to be dissolved in the new phosphate fire-resistant oil, and the operation is simple and easy. By accurately controlling the dosage and dissolution conditions (such as temperature and closed state) of the additives, it can be ensured that the prepared fire-resistant oil has stable performance. Since the preparation method is simple and low-cost, the preparation method of the present invention is easy to promote and apply in industrial production.

[0028] The high-stability phosphate fire-resistant oil of the present invention is suitable for various equipment such as steam turbine speed control systems and gas turbine speed control systems of power plants, and has wide applicability. The use of high-stability phosphate fire-resistant oil can reduce equipment failures and downtime caused by oil quality problems, thereby improving the power generation efficiency and economic benefits of power plants; and because the service life of the fire-resistant oil is extended, the replacement frequency and waste generation are reduced, so the application of the present invention also has the advantages of environmental protection and energy saving.

[0029] In summary, the method for adding the phosphite-based composite additive of the present invention is simple. After addition, the oxidation stability and hydrolysis stability of the phosphate fire-resistant oil can be improved, the stability of the acid value, resistivity and sludge precipitation during the use of the phosphate fire-resistant oil can be enhanced, the rate at which the acid value of the phosphate fire-resistant oil product increases and the resistivity decreases can be reduced, and the operating time before sludge is generated can be extended, thereby achieving the extension of the service life of the phosphate fire-resistant oil. Moreover, the phosphite-based composite additive is low in cost, the adding method is simple, and it has high economic value and social value. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In the present invention, unless otherwise specified, all the embodiments and preferred implementation methods mentioned herein can be combined with each other to form a new technical solution.

[0032] In the present invention, unless otherwise specified, all technical features and preferred features mentioned herein can be combined with each other to form a new technical solution.

[0033] In the present invention, unless otherwise specified, percentage (%) or part refers to the weight percentage or weight part relative to the composition.

[0034] In the present invention, unless otherwise specified, the components or preferred components involved can be combined with each other to form a new technical solution.

[0035] In the present invention, unless otherwise specified, the numerical range "a-b" represents an abbreviation of any real number combination between a and b, where a and b are real numbers. For example, the numerical range "6-22" means that all real numbers between "6-22" have been listed in this document, and "6-22" is just an abbreviation of these numerical combinations.

[0036] The “range” disclosed in the present invention is in the form of a lower limit and an upper limit, which can be one or more lower limits, and one or more upper limits, respectively.

[0037] In the present invention, the term "and / or" used herein refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0038] In the present invention, unless otherwise specified, each reaction or operation step can be carried out sequentially or in accordance with the sequence. Preferably, the reaction method herein is carried out sequentially.

[0039] Unless otherwise specified, the professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the described content may also be applied to the present invention.

[0040] The invention provides a phosphite-based composite additive, comprising bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol and Revonox 501. The three additives are mixed to obtain the phosphite-based composite additive. The phosphite-based composite additive can be used to improve the comprehensive performance of phosphate fire-resistant oil. The main component of the phosphate fire-resistant oil mentioned here is trixylene phosphate.

[0041] Preferably, by weight percentage, the additive amount of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite is 0.0020% to 0.0100% of the phosphate fire-resistant oil, the additive amount of 2,6-di-tert-butyl-p-cresol is 0.01% to 0.10% of the phosphate fire-resistant oil, and the additive amount of Revonox 501 is 0.0020% to 0.0050% of the phosphate fire-resistant oil.

[0042] Preferably, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite is sold by Xi'an Heping Chemical Glass Reagent Co., Ltd., has analytical purity, and is a phosphite antioxidant;

[0043] Preferably, Revonox 501 is sold by Shanghai Puzhan Industrial Co., Ltd., belongs to the benzofuranone system, is a carbon-neutral free radical ion scavenger, and is a multifunctional lactone-type thermal stabilizer and antioxidant;

[0044] The present invention also provides a high-stability phosphate fire-resistant oil, and the specific steps are as follows:

[0045] 1) determining the amount of the phosphate ester fire-resistant oil, and obtaining the amount of the phosphite-based composite additive according to the amount of the phosphate ester fire-resistant oil;

[0046] 2) taking 10000±3% of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite as the composite additive mother liquid solvent;

[0047] 3) Dissolve bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol and Revonox 501 in the composite additive mother solution solvent at 60°C±5°C in a sealed state;

[0048] 4) In a sealed state, the composite additive mother liquid is added into the phosphate ester fire-resistant oil to obtain a high-stability phosphate ester fire-resistant oil.

[0049] Example 1

[0050] Prepare the test sample of No. 1 high stability phosphate fire-resistant oil, and conduct full analysis and detection on the test sample of No. 1 high stability phosphate fire-resistant oil and phosphate fire-resistant oil:

[0051] 1. The test sample of No. 1 high stability phosphate fire-resistant oil is prepared as follows:

[0052] 1) Select a phosphate fire-resistant oil whose main component is trixylyl phosphate, take a sample bottle equipped with a sealed bottle stopper, weigh a certain amount of the phosphate fire-resistant oil into the sample bottle, calculate the mass of each additive based on the mass of the phosphate fire-resistant oil in the sample bottle, weigh it with an analytical balance and add it to the corresponding sample bottle, and cover the bottle cap to seal it.

[0053] The phosphite-based composite additive comprises: by weight percentage, 0.0050% of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 0.05% of 2,6-di-tert-butyl-p-cresol, and 0.0050% of Revonox 501;

[0054] Preferably, the volume of the sample bottle is 1000 mL, and the sealing stopper of the sample is a stopper made of polytetrafluoroethylene.

[0055] 2) placing the sealed sample bottle on a mixing device, which includes a vertically arranged triangular bracket, the bottom of which is fixed in a drying oven, a motor is arranged on the top of the triangular bracket, and the motor shaft is detachably connected to the sample bottle fixing plate. When the motor shaft is connected to the sample bottle fixing plate, the sample bottle fixing plate is driven by the motor to realize continuous rotation in the vertical direction at a speed of 5 r / min to 10 r / min. A plurality of sample bottle fixing clamps are arranged along the circumference of the sample bottle fixing plate for fixing the mouths of the plurality of sample bottles toward the center of the sample bottle fixing plate.

[0056] Preferably, the sample bottle fixing clamp comprises a bottle bottom fixing clamp, a bottle body fixing clamp and a bottle top fixing clamp, wherein the bottle top fixing clamp is a movable fixing clamp, which can prevent the sample bottle from falling off during rotation after being tightened.

[0057] 3) Connect the sample bottle fixing plate with the sample bottles to the motor shaft, keep the temperature in the drying oven constant at 60°C ± 5°C, rotate the sample bottle fixing plate to rotate and mix the samples for 1 hour to ensure that the additives are dissolved in the phosphate fire-resistant oil and mixed evenly therewith.

[0058] 4) Take the sample out of the drying oven and cool it to room temperature to obtain a test sample of No. 1 high-stability phosphate fire-resistant oil (when testing the sample, the mother liquor preparation stage can be skipped and the test can be performed directly).

[0059] Second, the full analysis test is as follows:

[0060] In order to detect the actual effect of the phosphite-based composite additive of the present invention on improving phosphate fire-resistant oil after being added to phosphate fire-resistant oil, the test samples of phosphate fire-resistant oil and No. 1 high-stability phosphate fire-resistant oil were fully analyzed. The test results are shown in Table 1.

[0061] Table 1 Test results of base oil samples before and after adding composite additives

[0062]

[0063] It can be seen from Table 1 that the phosphite-based composite additive of the present invention has no negative impact on other properties of phosphate fire-resistant oil, so the phosphite-based composite additive of the present invention is suitable as an additive for phosphate fire-resistant oil; compared with phosphate fire-resistant oil, the high-stability phosphate fire-resistant oil of the present invention has improved antioxidant and hydrolysis resistance, especially antioxidant ability, which is improved by about 80% compared with the base oil.

[0064] When the composite additive combination does not contain bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, the oxidation stability test result of the oil sample is 0.10 mg(KOH) / g. After adding bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, the oxidation stability of the phosphate ester fire-resistant oil can be improved to 0.04 mg(KOH) / g, an increase of up to 60%.

[0065] Preferably, the hydrolysis stability detection method used in the full analysis test is as follows:

[0066] 1) Detect the acid value A0 of the phosphate fire-resistant oil to be tested and the blank acid value a0 of the water to be used for the test;

[0067] 2) In a closed environment with a protective atmosphere, add water to the phosphate ester fire-resistant oil to be tested, with a weight ratio of water to the phosphate ester fire-resistant oil to be tested of 1:3, and perform a hydrolysis reaction at a constant temperature of 120℃±2℃ for 18h;

[0068] 3) separating the mixture of the phosphate fire-resistant oil and water after the hydrolysis reaction to obtain the phosphate fire-resistant oil layer after the hydrolysis reaction and the water layer, and detecting the acid value A1 of the phosphate fire-resistant oil layer after the hydrolysis reaction and the acid value a1 of the water layer respectively;

[0069] 4) The hydrolysis stability of phosphate ester fire-resistant oil is expressed by the increase in acid value of phosphate ester fire-resistant oil and water. The calculation formula is shown in formula (1):

[0070] A=(A1-A0)+(a1-a0)(1).

[0071] The water may be distilled water or deionized water and must meet the requirements of secondary water in GB / T 6682. The indicator used for titrating the water is a phenolphthalein indicator. The standard alkaline solution used for titrating the acid value is a potassium hydroxide ethanol standard solution. The concentration of potassium hydroxide in the solution is 0.03 mgKOH / g to 0.06 mgKOH / g.

[0072] Example 2

[0073] The difference from Example 1 is that the phosphite-based composite additive includes: by weight percentage, the additive amount of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite is 0.0020%, the additive amount of 2,6 di-tert-butyl-p-cresol is 0.01%, and the additive amount of Revonox 501 is 0.0020%. The test sample of No. 2 high-stability phosphate fire-resistant oil is obtained, and the test results of key indicators are shown in Table 2:

[0074] Table 2 Test results of samples after adding composite additives to base oil

[0075]

[0076]

[0077] It can be seen from Table 2 that the high stability phosphate fire-resistant oil of the present invention has improved antioxidant and hydrolysis resistance compared with phosphate fire-resistant oil, especially the antioxidant capacity, which is improved by about 70% compared with the base oil.

[0078] Example 3

[0079] Different from Example 1, the phosphite-based composite additive includes: by weight percentage, the additive amount of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite is 0.0100%, the additive amount of 2,6 di-tert-butyl-p-cresol is 0.10%, and the additive amount of Revonox 501 is 0.0030%. The test sample of No. 3 high-stability phosphate fire-resistant oil is obtained, and the test results of key indicators are shown in Table 3:

[0080] Table 3 Test results of samples after adding composite additives to base oil

[0081]

[0082] It can be seen from Table 3 that the high stability phosphate fire-resistant oil of the present invention has improved antioxidant and hydrolysis resistance compared with phosphate fire-resistant oil, especially the antioxidant capacity, which is improved by about 80% compared with the base oil.

[0083] Example 4

[0084] Different from Example 1, TURBOFLUID 46SJ phosphate fire-resistant oil from the market is selected, and the added phosphite-based composite additive includes: by weight percentage, the addition amount of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite is 0.0050%, the addition amount of 2,6 di-tert-butyl-p-cresol is 0.05%, and the addition amount of Revonox 501 is 0.0050%. The test sample of No. 4 high-stability phosphate fire-resistant oil is obtained, and the test results of key indicators are shown in Table 4:

[0085] Table 4 Test results of samples after adding composite additives to base oil

[0086]

[0087] It can be seen from Table 4 that after adding the composite additive of the present invention, the antioxidant capacity and hydrolysis resistance of TURBOFLUID 46SJ fire-resistant oil are improved.

[0088] In summary, the phosphite-based composite additive of the present invention is specifically bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol and Revonox The invention discloses a mixture of phosphate fire-resistant oil and 501, wherein the additive amount is 0.0020% to 0.0100% of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 0.01% to 0.10% of 2,6-di-tert-butyl-p-cresol, and 0.0020% to 0.0050% of Revonox501; when the three additives are used in combination, a significant synergistic effect is exhibited, and the adding method is simple. After adding, the oxidation stability and hydrolysis stability of phosphate fire-resistant oil can be improved, the acid value, resistivity and sludge precipitation stability of phosphate fire-resistant oil can be enhanced, the speed of acid value increase and resistivity decrease of phosphate fire-resistant oil products can be reduced, and the operating time before sludge is generated can be extended, thereby achieving the extension of the service life of phosphate fire-resistant oil. The invention also has low cost, simple adding method, and high economic value and social value.

Claims

1. A phosphite-based composite additive, characterized in that: The composite additive is a mixture of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol and Revonox 501.

2. A phosphite-based composite additive according to claim 1, characterized in that: Calculated by weight, the additive amount of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite accounts for 0.0020% to 0.0100% of the phosphate ester fire-resistant oil, the additive amount of 2,6-di-tert-butyl-p-cresol accounts for 0.01% to 0.10% of the phosphate ester fire-resistant oil, and the additive amount of Revonox501 accounts for 0.0020% to 0.0050% of the phosphate ester fire-resistant oil.

3. A phosphite-based composite additive according to claim 2, characterized in that: The main component of the phosphate fire-resistant oil is trixylene phosphate.

4. A high-stability phosphate fire-resistant oil, characterized in that: A phosphite-based composite additive is added to the phosphate fire-resistant oil. The composite additive is a mixture of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol and Revonox 501.

5. A high-stability phosphate fire-resistant oil according to claim 4, characterized in that: The additive amount of the phosphite-based composite additive in the phosphate fire-resistant oil is specifically as follows: the additive amount of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite accounts for 0.0020% to 0.0100% of the phosphate fire-resistant oil, the additive amount of 2,6-di-tert-butyl-p-cresol accounts for 0.01% to 0.10% of the phosphate fire-resistant oil, and the additive amount of Revonox 501 accounts for 0.0020% to 0.0050% of the phosphate fire-resistant oil.

6. The high-stability phosphate fire-resistant oil according to claim 4, characterized in that: The main component of the phosphate fire-resistant oil is trixylene phosphate.

7. A method for preparing a high-stability phosphate fire-resistant oil according to any one of claims 4 to 6, characterized in that: The specific steps are as follows: S1: determining the dosage of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol and Revonox 501 according to the total amount of oil products, dissolving bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol and Revonox 501 in new phosphate fire-resistant oil to obtain a phosphite-based composite additive mother liquid; In the S2 sealed state, the composite additive mother liquid is added into the phosphate ester fire-resistant oil.

8. The method for preparing a high-stability phosphate fire-resistant oil according to claim 7, characterized in that: In S1, at 60°C±5°C, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol and Revonox 501 are dissolved in a new phosphate fire-resistant oil of 10,000 times the weight of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite in a sealed state to obtain a phosphite-based composite additive mother solution.

9. Use of the high-stability phosphate fire-resistant oil according to any one of claims 4 to 6 in a steam turbine speed control system of a power plant.

10. Use of the high-stability phosphate fire-resistant oil according to any one of claims 4 to 6 in a gas turbine speed control system of a power plant.

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