Composite additive based on 2, 6-butylated hydroxytoluene, phosphate fire-resistant oil and application

Abstract

The invention provides a composite additive based on 2, 6-butylated hydroxytoluene, phosphate fire-resistant oil and application, the composite additive is a mixture of 2, 6-butylated hydroxytoluene and Revonox 501, the addition amount of 2, 6-butylated hydroxytoluene is 0.01%-0.10%, the addition amount of Revonox 501 is 0.0020%-0.0050%, the addition amount of 2, 6-butylated hydroxytoluene is 0.01%-0.10%, the addition amount of 2, 6-butylated hydroxytoluene is 0.0020%-0.0050%, and the addition amount of 2, 6-butylated hydroxytoluene is 0.01%-0.10%. After the phosphate fire-resistant oil is added with the composite additive, the comprehensive performance of the phosphate fire-resistant oil in the operation process can be improved, and the defects that after new phosphate fire-resistant oil is loaded into a system, the action flexibility of a steam turbine assembly is reduced and a servo valve of a speed regulating system is corroded and jammed due to the phenomena that the acid value is increased, the resistivity is reduced, oil sludge is generated and the like in the use process are overcome; and the operation safety of a turbine set of a power plant is influenced.

Description

Technical Field

[0001] The invention belongs to the technical field of phosphate fire-resistant oil, and in particular to a composite additive based on 2,6-di-tert-butyl-p-cresol and a phosphate fire-resistant oil and application thereof. Background Art

[0002] Phosphate ester fire-resistant oil is a fully synthetic phosphate ester flame-retardant hydraulic fluid. Due to its excellent fire retardant and lubricating properties, it is widely used in the speed control system of steam turbines and gas turbines.

[0003] The composition of phosphate fire-resistant oil is triaryl phosphate ester. The difference between different brands of products lies in the different substituents on the benzene ring. Since phosphate fire-resistant oil is a chemical synthetic product, it has poor compatibility with additives, and most additives cannot be added. Compared with mineral oils, phosphate fire-resistant oil deteriorates quickly. During use, the acid value of the oil often increases, the resistivity decreases quickly, and sludge is generated after a short running time. These can lead to reduced flexibility of the turbine parts and corrosion and jamming of the servo valve of the speed control system. In severe cases, it can cause abnormal shutdown accidents of the unit, affecting the safe operation of the power plant turbine unit. At the same time, phosphate fire-resistant oil is expensive, and frequent oil changes will increase the economic cost of the power industry; the replaced phosphate fire-resistant oil is a general hazardous waste, and improper disposal will pollute water and soil.

[0004] There are two main reasons why phosphate fire-resistant oils age during use: one is oil oxidation, and the other is oil hydrolysis.

[0005] The oxidation of fire-resistant oil mainly occurs on the substituents of the aromatic ring. Due to the complexity of the oil structure itself and the variability of the external conditions of the oxidation reaction, the oxidation process is very complicated. The free radical chain reaction theory is more recognized in the auto-oxidation mechanism of oil. The reaction process includes three stages: chain initiation, development and termination. The initiation of the chain is mainly caused by the contact of the substituents of the aromatic ring with active oxygen. A part of the RH chain will be broken, generating alkyl radicals and hydrogen peroxide radicals; phosphate fire-resistant oil easily absorbs moisture in the air during operation and is easily hydrolyzed under high temperature and high pressure. The hydrolysis reaction is mainly divided into three steps, which respectively form diaryl phosphate, monoaryl phosphate, phosphoric acid and corresponding alkylphenol. In actual operation, due to different operating conditions of the oil, the aging process of phosphate fire-resistant oil is very complicated. The oxidation reaction and hydrolysis reaction will proceed simultaneously and promote each other. The aging product is also a mixture of various organic substances.

[0006] In order to improve the performance of phosphate ester fire-resistant oil in operation, researchers have tried to add 2,6-di-tert-butyl-p-cresol to improve the acid value, resistivity and sludge precipitation stability of phosphate ester fire-resistant oil during use. After adding 2,6-di-tert-butyl-p-cresol to phosphate ester fire-resistant oil, it can indeed improve the stability of phosphate ester fire-resistant oil in the early stage, but it will cause the acid value of phosphate ester fire-resistant oil to increase rapidly in the later stage of degradation. Therefore, it is necessary to study how to improve the comprehensive anti-degradation performance of oil products, increase the stability of phosphate ester fire-resistant oil and extend its service life by adding composite additives. Summary of the invention

[0007] In order to solve the problems existing in the prior art, the present invention provides a composite additive based on 2,6-di-tert-butyl-p-cresol and a phosphate fire-resistant oil and application thereof. The composite additive is a mixture of 2,6-di-tert-butyl-p-cresol and Revonox 501, wherein the addition amount of 2,6-di-tert-butyl-p-cresol is 0.01%-0.10%, and the addition amount of Revonox 501 is 0.0020%-0.0050%. After the composite additive is added to the phosphate fire-resistant oil, the comprehensive performance of the phosphate fire-resistant oil during operation can be improved, and the problems that after the new phosphate fire-resistant oil is loaded into the system, the acid value increases and the resistivity decreases quickly, and sludge is generated prematurely during use are overcome, thereby reducing the flexibility of the steam turbine parts and causing the servo valve of the speed control system to corrode and become stuck, thereby affecting the safe operation of the steam turbine unit in the power plant.

[0008] To achieve the above object, the present invention provides the following technical solution: a composite additive based on 2,6-di-tert-butyl-p-cresol, wherein the composite additive comprises 2,6-di-tert-butyl-p-cresol and Revonox 501.

[0009] Furthermore, the composite additive includes, by weight percentage, 0.01% to 0.10% of 2,6-di-tert-butyl-p-cresol and 0.0020% to 0.0050% of Revonox 501.

[0010] Furthermore, by weight percentage, the composite additive includes 0.0500% of 2,6-di-tert-butyl-p-cresol and 0.0050% of Revonox 501.

[0011] The present invention also provides application of the composite additive in improving the comprehensive performance of phosphate fire-resistant oil.

[0012] The present invention also provides a phosphate fire-resistant oil, the raw materials of which include phosphate fire-resistant oil, 2,6-di-tert-butyl-p-cresol and Revonox 501, wherein, by weight percentage, the addition amount of 2,6-di-tert-butyl-p-cresol is 0.01% to 0.10% of the total amount of the phosphate fire-resistant oil, and the addition amount of Revonox 501 is 0.0020% to 0.0050% of the total amount of the phosphate fire-resistant oil.

[0013] Furthermore, the phosphate fire-resistant oil is trixylene phosphate.

[0014] The present invention also provides a method for preparing a phosphate fire-resistant oil, the specific steps of which are as follows:

[0015] S1 obtains the total amount of phosphate ester fire-resistant oil, and calculates the addition amount of 2,6-di-tert-butyl-p-cresol and Revonox 501 according to the total amount of phosphate ester fire-resistant oil;

[0016] S2 adds calculated amounts of 2,6-di-tert-butyl-p-cresol and Revonox 501 into phosphate fire-resistant oil, and mixes them in a constant temperature and closed environment to obtain phosphate fire-resistant oil.

[0017] Furthermore, in S2, the constant temperature is a fixed temperature within the range of 60°C±5°C.

[0018] The present invention also provides application of the phosphate fire-resistant oil in a turbine speed regulating system of a power plant.

[0019] The present invention also provides application of the phosphate fire-resistant oil in a gas turbine speed control system of a power plant.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] The present invention provides a composite additive based on 2,6-di-tert-butyl-p-cresol. Although 2,6-di-tert-butyl-p-cresol, as a traditional antioxidant, has the problem of poor hydrolysis stability when added alone to phosphate fire-resistant oil, it not only makes up for the deficiency of 2,6-di-tert-butyl-p-cresol in anti-oxidation after being combined with Revonox 501, but also enhances the ability of Revonox 501 to capture free radicals, and can significantly improve the comprehensive anti-degradation performance of phosphate fire-resistant oil at a very low addition amount, ensuring that it does not excessively affect the performance of oil products, and can effectively exert their respective advantages. The adding process is simple, and the composite additive only needs to be compounded and directly added to the phosphate fire-resistant oil, without complicated operation or equipment. And because the addition amount of the composite additive is extremely low, the cost is low, and at the same time, the service life of the phosphate fire-resistant oil can be significantly extended, the maintenance cost and replacement frequency are reduced, and it has a high economic value.

[0022] After the composite additive is added to the phosphate fire-resistant oil of the present invention, the acid value stability, resistivity stability and sludge precipitation stability of the phosphate fire-resistant oil are significantly improved, effectively extending the operation time of the oil product, solving the problems of increased acid value, reduced resistivity, sludge generation and the like during the use of the new phosphate fire-resistant oil, avoiding the negative effects of these problems on the flexibility of the movement of the turbine parts and the servo valve of the speed control system, and improving the safety and reliability of the steam turbine unit in the power plant.

[0023] Phosphate ester fire-resistant oil is widely used in many fields such as electric power, metallurgy, chemical industry, etc. due to its excellent performance. The composite additive of the present invention further improves the comprehensive performance of phosphate ester fire-resistant oil, making its application in these fields more reliable and efficient. The service life of phosphate ester fire-resistant oil is extended, the frequency of oil replacement and treatment is reduced, which is conducive to reducing environmental pollution and saving resources, and is in line with the current development trend of environmental protection and energy saving.

[0024] In summary, the composite additive based on 2,6-di-tert-butyl-p-cresol provided by the present invention and its application in phosphate fire-resistant oil achieves a dual improvement in economic and social benefits by optimizing the additive ratio, simplifying the addition process, and improving oil performance. DETAILED DESCRIPTION

[0025] 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.

[0026] 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.

[0027] 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.

[0028] In the present invention, unless otherwise specified, percentage (%) or part refers to the weight percentage or weight part relative to the composition.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] The present invention provides a composite additive based on 2,6-di-tert-butyl-p-cresol, which comprises, by weight percentage, 0.01% to 0.10% of 2,6-di-tert-butyl-p-cresol and 0.0020% to 0.0050% of Revonox 501, wherein 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 heat stabilizer and antioxidant;

[0036] After the composite additive is added to the phosphate ester fire-resistant oil, the added composite additive can improve the comprehensive performance of the phosphate ester fire-resistant oil. The main component of the phosphate ester fire-resistant oil targeted by the present invention is trixylyl phosphate. The specific steps for preparing the phosphate ester fire-resistant oil with the composite additive added are as follows:

[0037] S1: preparing a phosphate ester fire-resistant oil sample: adding a certain amount of composite additives into a phosphate ester fire-resistant oil whose main component is trixylyl phosphate to obtain a phosphate ester fire-resistant oil sample;

[0038] S1.1 Composite additives and content:

[0039] The composite additive comprises 2,6-di-tert-butyl-p-cresol and Revonox 501; in terms of weight percentage, the addition amount of 2,6-di-tert-butyl-p-cresol is 0.01% to 0.10% of the total amount of the phosphate ester fire-resistant oil, and the addition amount of Revonox 501 is 0.0020% to 0.0050% of the total amount of the phosphate ester fire-resistant oil;

[0040] S1.2 Preparation of phosphate ester fire-resistant oil samples:

[0041] S1.2.1 Take a glass bottle equipped with a sealed bottle stopper, weigh a certain amount of phosphate ester fire-resistant oil and place it in the glass bottle; calculate the amount of 2,6-di-tert-butyl-p-cresol and Revonox 501 to be added according to the total mass of the phosphate ester fire-resistant oil in the sample bottle, weigh the calculated amount of 2,6-di-tert-butyl-p-cresol and Revonox 501 with an analytical balance and add them to the corresponding sample bottle, then cover the bottle cap and seal it.

[0042] Preferably, the volume of the sample bottle is 1000 mL, and the sealing stopper of the sample is a stopper made of polytetrafluoroethylene.

[0043] S1.2.2 Place 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, and a motor is arranged on the top of the triangular bracket. 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 achieve continuous rotation in the vertical direction at a speed of 5r / min to 10r / min. A plurality of sample bottle fixing clamps are arranged along the circumference of the sample bottle fixing plate for fixing the mouths of a plurality of sample bottles toward the center of the sample bottle fixing plate.

[0044] 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.

[0045] S1.2.3 Connect the sample bottle fixing plate with the sample bottles to the motor shaft. Keep the temperature in the drying oven constant at a fixed temperature of 60℃±5℃. Rotate the sample bottle fixing plate to rotate and mix the samples for 1 hour to ensure that 2,6-di-tert-butyl-p-cresol and Revonox501 are dissolved in the phosphate fire-resistant oil and mixed evenly with the phosphate fire-resistant oil. Take the mixture out of the drying oven and cool it to room temperature to obtain the phosphate fire-resistant oil sample.

[0046] Compatibility test and analysis of S2 composite additive and phosphate ester fire-resistant oil

[0047] S2.1 Test the acid value, resistivity, oxidation stability, hydrolysis stability and air release value of the phosphate ester fire-resistant oil sample, and compare them with the acid value, resistivity, oxidation stability, hydrolysis stability and air release value of the original phosphate ester fire-resistant oil (phosphate ester fire-resistant oil without composite additives) to determine whether the composite additive is compatible with the phosphate ester fire-resistant oil. If the quality of the above indicators is significantly reduced, it indicates that the composite additive is incompatible with the phosphate ester fire-resistant oil; if there is improvement on some indicators and no effect on other indicators, it means that the composite additive is compatible with the phosphate ester fire-resistant oil, and further closed cup aging test is carried out.

[0048] S2.2 A closed cup aging test is conducted on the phosphate ester fire-resistant oil sample and the original phosphate ester fire-resistant oil. During the aging test, samples of the phosphate ester fire-resistant oil sample and the original phosphate ester fire-resistant oil are taken regularly, and the acid value, resistivity, and sludge precipitation data are tested. The acid value, resistivity, and sludge precipitation data of the phosphate ester fire-resistant oil sample and the original phosphate ester fire-resistant oil are compared. If the deterioration rate of the above-mentioned quality indicators is significantly accelerated, it indicates that the composite additive and the phosphate ester fire-resistant oil are incompatible. Otherwise, it is considered that the composite additive is compatible with the phosphate ester fire-resistant oil.

[0049] Preferably, a 1000 mL ground-mouth conical flask is used during the aging process, and the sample amount in the flask is 600 g;

[0050] Preferably, 3 copper wires with a purity of not less than 99.9%, a diameter of 1.00 mm to 1.02 mm, and a length of 330 mm are added to the 600 g sample;

[0051] Preferably, after removing the surface oxide layer of the copper wire with mixed acid, the acid attached to the surface is washed off with running tap water and distilled water in turn, and then the copper wire is placed in a beaker containing ethanol and acetone for 10 seconds in turn, and placed at room temperature for 5 minutes to dry the solvent;

[0052] Preferably, the mixed acid for cleaning the copper wire is a mixture of phosphoric acid and nitric acid, with a mixing ratio of 1:3;

[0053] Preferably, the water content of the samples compared in parallel during the aging process is consistent, between 200 mg / L and 300 mg / L;

[0054] Preferably, the number of time points for longitudinal comparison of a single sample is 7 to 10;

[0055] Preferably, the samples for longitudinal and transverse comparisons are prepared at the same time;

[0056] Preferably, samples for horizontal comparison are sampled at the same aging time.

[0057] Analysis of the effect of different addition amounts of S3 composite additives on improving the comprehensive performance of phosphate fire-resistant oil

[0058] Phosphate ester fire-resistant oil samples were obtained by adding different amounts of composite additives into phosphate ester fire-resistant oil. The phosphate ester fire-resistant oil samples were subjected to closed cup aging test. During the aging test, samples were taken regularly to detect the acid value, resistivity and sludge precipitation of the phosphate ester fire-resistant oil samples. The quality indicators of the original phosphate ester fire-resistant oil and the phosphate ester fire-resistant oil samples with different amounts of composite additives were compared to clarify the effects of different amounts of composite additives on improving the comprehensive performance of phosphate ester fire-resistant oil.

[0059] After 2,6-di-tert-butyl-p-cresol is added to phosphate ester fire-resistant oil, the hydrolysis stability of the oil will deteriorate as the amount of addition increases. When the additive is too low, the oil will lose protection after it is consumed during operation. Revonox 501 is a highly efficient active free radical scavenger, but it has limited effect in improving the antioxidant capacity of oil. When Revonox 501 and 2,6-di-tert-butyl-p-cresol are used in combination, there is a very high synergistic effect, and adding a very small amount of both will improve the comprehensive anti-degradation performance of phosphate ester fire-resistant oil. In the addition process, Revonox 501 and 2,6-di-tert-butyl-p-cresol can be directly added to the phosphate ester fire-resistant oil. The addition method is simple. After addition, the stability of the acid value, resistivity and sludge precipitation changes during the use of phosphate ester fire-resistant oil can be improved, the speed of the acid value increase and resistivity decrease of phosphate ester fire-resistant oil can be reduced, and the operating time before sludge is generated can be extended, thereby extending the service life of phosphate ester fire-resistant oil. It is low in cost, simple in addition method, and has high economic and social value.

[0060] Example 1

[0061] The phosphate fire-resistant oil sample 1 is prepared in the following specific steps:

[0062] S1 Sample preparation, as follows:

[0063] S1.1 Take a 1000mL sample bottle, numbered as 1, and weigh 1000.0g of phosphate fire-resistant oil into the sample bottle;

[0064] S1.2 Weigh 0.0500 g of Revonox 501 and 0.5000 g of 2,6-di-tert-butyl-p-cresol, add the additives into the sample bottle, and seal the bottle with the cap.

[0065] S1.3 Fix the sealed sample bottle on the mixing device at a speed of 10r / min;

[0066] S1.4 Place the mixing device of S1.3 in a drying oven kept at a constant temperature of 65°C and fix it, rotate the sample for 1 hour to ensure that 2,6-di-tert-butyl-p-cresol and Revonox 501 are dissolved in the phosphate fire-resistant oil and mixed evenly with the phosphate fire-resistant oil, take the mixture out of the drying oven, cool it to room temperature to obtain phosphate fire-resistant oil sample 1.

[0067] Compatibility test and analysis of S2 composite additive and phosphate ester fire-resistant oil

[0068] S2.1 The acid value, resistivity, oxidation stability, hydrolysis stability and air release value of the original phosphate ester fire-resistant oil and phosphate ester fire-resistant oil sample 1 were tested. The test results are shown in Table 1.

[0069] Table 1 Preliminary solubility test data of composite additives

[0070]

[0071] Note: The repeatability deviation of acid value is 0.02mgKOH / g, and the resistivity is greater than 1.0×10 10 Ω·cm, the repeatability is no more than 25% of the relative error (4.5×10 10 Ω·cm), when the air release value is less than 5min, the repeatability is no more than 0.7min.

[0072] Therefore, compared with the results of the original phosphate ester fire-resistant oil, the resistivity of phosphate ester fire-resistant oil sample 1 is 5.0×10 10 Ω·cm, the hydrolysis stability and oxidation stability of phosphate ester fire-resistant oil sample 1 are better than those of the original phosphate ester fire-resistant oil. Therefore, it is believed that the addition of composite additives can improve the volume resistivity, antioxidant properties and hydrolysis resistance of the oil, and has no negative effect on phosphate ester fire-resistant oil.

[0073] The test results in Table 1 show that the hydrolysis stability, oxidation stability and resistivity of the phosphate ester fire-resistant oil sample 1 after adding the composite additive are significantly improved compared with the original phosphate ester fire-resistant oil, and there is no negative impact on other indicators of the phosphate ester fire-resistant oil, so further closed cup aging tests can be carried out.

[0074] S2.2 A closed cup aging test was performed on the phosphate ester fire-resistant oil sample 1 and the original phosphate ester fire-resistant oil. During the aging test, samples were taken regularly to test the acid value, resistivity, and sludge precipitation of the phosphate ester fire-resistant oil sample 1 and the original phosphate ester fire-resistant oil. The test results are shown in Tables 2 to 4.

[0075] Table 2 Acid value test results of each sample during 115℃ closed cup aging test

[0076]

[0077]

[0078] Table 3 Resistivity test results of each sample during 115℃ closed cup aging test

[0079]

[0080] Table 4 Detection results of sludge precipitation during the 115℃ closed cup aging test of each sample

[0081]

[0082] The test results in Tables 2 to 4 show that compared with the original phosphate ester fire-resistant oil, the phosphate ester fire-resistant oil sample 1 improves the tendency of sludge precipitation during aging, reduces the trend of acid value increase and resistivity decrease, indicating that the composite additive of the present invention is suitable as an additive for phosphate ester fire-resistant oil.

[0083] S3 prepares phosphate ester fire-resistant oil comparison samples with a single additive, including, by weight percentage, a phosphate ester fire-resistant oil comparison sample with 0.0500% 2,6-di-tert-butyl-p-cresol added and a phosphate ester fire-resistant oil comparison sample with 0.0050% Revonox 501 added, performs a closed cup aging test on the two phosphate ester fire-resistant oil comparison samples, and compares the closed cup aging test results with those of the original phosphate ester fire-resistant oil and the phosphate ester fire-resistant oil sample 1. The comparison of the effects is shown in Tables 5 to 7:

[0084] Table 5 Acid value test results of each sample during 115℃ closed cup aging test

[0085]

[0086] Table 6 Results of sludge precipitation during the 115℃ closed cup aging test of each sample

[0087]

[0088] Table 7 Volume resistivity test results of each sample during 115℃ closed cup aging test

[0089]

[0090] Tables 5 to 7 show that the composite additive of 2,6-di-tert-butyl-p-cresol and Revonox 501 can better improve the acid value index of phosphate fire-resistant oil during aging compared with single 2,6-di-tert-butyl-p-cresol and Revonox 501 added at the same content.

[0091] Example 2

[0092] The phosphate fire-resistant oil sample 2 was prepared in the following specific steps:

[0093] S1 Take a 1000mL sample bottle, numbered as No. 2, and weigh 1000.0g of phosphate fire-resistant oil into the sample bottle;

[0094] S2 weighed 0.0200 g of Revonox 501 and 0.1000 g of 2,6-di-tert-butyl-p-cresol, added the additives into the sample bottle, and sealed it with a cap.

[0095] S3 fixes the sealed sample bottle on the mixing device at a rotation speed of 10r / min;

[0096] S4 puts the mixing device of S3 into a drying oven kept at a constant temperature of 60°C, rotates the sample for 1 hour, ensures that 2,6-di-tert-butyl-p-cresol and Revonox 501 are dissolved in the phosphate fire-resistant oil and are evenly mixed with the phosphate fire-resistant oil, takes the mixture out of the drying oven, and cools it to room temperature to obtain the phosphate fire-resistant oil sample 2.

[0097] Example 3

[0098] The phosphate fire-resistant oil sample 3 was prepared in the following specific steps:

[0099] S1 Take a 1000mL sample bottle, numbered 3, and weigh 1000.0g of phosphate fire-resistant oil into the sample bottle;

[0100] S2 Weigh 0.0300 g of Revonox 501 and 1 g of 2,6-di-tert-butyl-p-cresol, add the additives into the sample bottle, and seal it with the cap.

[0101] S3 fixes the sealed sample bottle on the mixing device at a rotation speed of 10r / min;

[0102] S4: placing the mixing device of S3 into a drying oven at a fixed temperature of 55°C, rotating the sample for 1 hour to ensure that 2,6-di-tert-butyl-p-cresol and Revonox 501 are dissolved in the phosphate fire-resistant oil and evenly mixed with the phosphate fire-resistant oil, taking the mixture out of the drying oven, and cooling it to room temperature to obtain phosphate fire-resistant oil sample 3.

[0103] The closed cup aging test was carried out on the original phosphate ester fire-resistant oil and the phosphate ester fire-resistant oil samples 1 to 3. During the aging test, samples were taken regularly to test the acid value, sludge precipitation and resistivity of the original phosphate ester fire-resistant oil and the phosphate ester fire-resistant oil samples 1 to 3. The test results are shown in Tables 8 to 10:

[0104] Table 8 Acid value test results of each sample during 115℃ closed cup aging test

[0105]

[0106] Table 9 Results of sludge precipitation during the 115℃ closed cup aging test of each sample

[0107]

[0108]

[0109] Table 10 Volume resistivity test results of each sample during 115℃ closed cup aging test

[0110]

[0111] Tables 8 to 10 show that when 0.01% to 0.10% of 2,6-di-tert-butyl-p-cresol and 0.0020% to 0.0050% of Revonox 501 composite additives are added to phosphate ester fire-resistant oil, the quality indicators of acid value and sludge precipitation of phosphate ester fire-resistant oil samples during aging can be optimally improved compared with the original phosphate ester fire-resistant oil. Therefore, the composite additive of Revonox 501 and di-tert-butyl-p-cresol is suitable as an additive for fire-resistant oil products, and the addition amounts are 0.0020% to 0.0050% and 0.01% to 0.10%, respectively.

Claims

1. A composite additive based on 2,6-di-tert-butyl-p-cresol, characterized in that: The composite additive comprises 2,6-di-tert-butyl-p-cresol and Revonox 501.

2. A composite additive based on 2,6-di-tert-butyl-p-cresol according to claim 1, characterized in that: In terms of weight percentage, the composite additive includes 0.01% to 0.10% of 2,6-di-tert-butyl-p-cresol and 0.0020% to 0.0050% of Revonox 501.

3. A composite additive based on 2,6-di-tert-butyl-p-cresol according to claim 1, characterized in that: In terms of weight percentage, the composite additive includes 0.0500% of 2,6-di-tert-butyl-p-cresol and 0.0050% of Revonox 501.

4. Use of the composite additive according to any one of claims 1 to 3 in improving the comprehensive properties of phosphate ester fire-resistant oils.

5. A phosphate fire-resistant oil, characterized in that: The raw materials include phosphate fire-resistant oil, 2,6-di-tert-butyl-p-cresol and Revonox 501, wherein, by weight percentage, the addition amount of 2,6-di-tert-butyl-p-cresol is 0.01% to 0.10% of the total amount of the phosphate fire-resistant oil, and the addition amount of Revonox 501 is 0.0020% to 0.0050% of the total amount of the phosphate fire-resistant oil.

6. A phosphate fire-resistant oil according to claim 5, characterized in that: The phosphate fire-resistant oil is trixylene phosphate.

7. The method for preparing a phosphate fire-resistant oil according to claim 5 or 6, characterized in that: The specific steps are as follows: S1 obtains the total amount of phosphate ester fire-resistant oil, and calculates the addition amount of 2,6-di-tert-butyl-p-cresol and Revonox 501 according to the total amount of phosphate ester fire-resistant oil; S2 adds calculated amounts of 2,6-di-tert-butyl-p-cresol and Revonox 501 into phosphate fire-resistant oil, and mixes them in a constant temperature and closed environment to obtain phosphate fire-resistant oil.

8. The method for preparing a phosphate fire-resistant oil according to claim 7, characterized in that: In S2, the constant temperature is a fixed temperature within 60°C±5°C.

9. Use of the phosphate fire-resistant oil according to claim 5 or 6 in a turbine speed control system of a power plant.

10. Use of the phosphate fire-resistant oil according to claim 5 or 6 in a gas turbine speed control system of a power plant.

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