A phosphite-based composite additive and a highly stable phosphate ester fire-resistant oil and its application

Abstract

This invention provides a phosphite-based composite additive and a highly stable phosphate ester fire-resistant oil, as well as their applications. 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. Adding the phosphite-based composite additive to the phosphate ester fire-resistant oil can simultaneously improve the antioxidant and hydrolysis resistance of the phosphate ester fire-resistant oil, enhance the stability of the phosphate ester fire-resistant oil product, and provide a guarantee for the safe operation of generator sets.

Description

Technical Field

[0001] This invention belongs to the field of phosphate ester fire-resistant oil technology, specifically to a phosphite-based composite additive and a highly stable phosphate ester fire-resistant oil and its application. Background Technology

[0002] Phosphate ester fire-resistant oil, as a fully synthetic phosphate ester flame-retardant hydraulic fluid, occupies an important position in the speed control systems of steam turbines and gas turbines due to its excellent fire-retardant and lubricating properties. Its unique triaryl phosphate ester composition endows it with these unique properties, but it is precisely this component characteristic that makes phosphate ester fire-resistant oil face a series of challenges during use.

[0003] Because phosphate ester fire-resistant oil is a chemically synthesized product, its molecular structure is relatively complex, resulting in poor compatibility with most additives. Therefore, without any additives, phosphate ester fire-resistant oil will deteriorate rapidly during use. Specifically:

[0004] Increased acid value: Under the influence of oxygen, heat and moisture, phosphate ester fire-resistant oil is prone to oxidation and hydrolysis, generating acidic polar substances, which leads to a continuous increase in the acid value of the oil.

[0005] Decreased resistivity: As the acid value increases, the electrical properties of oil are also affected, and the resistivity gradually decreases, which affects the insulation performance of electrical equipment.

[0006] Oil sludge formation: As the oxidation and hydrolysis reactions deepen, the reaction products further condense, forming oil sludge. The accumulation of oil sludge can clog oil passages, affecting the normal operation of the speed control system.

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

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

[0009] Additives are not very effective: Even additives that can be added to phosphate ester fire-resistant oil often have insufficient effect and cannot fundamentally solve problems such as rapid oil deterioration, increased acid value, decreased resistivity and sludge formation.

[0010] During use, oil deterioration and sludge buildup can clog oil passages, causing turbine components to operate inflexibly and affecting the normal operation of the unit. The accumulation of acidic substances can corrode components such as servo valves in the speed control system, leading to jamming and, in severe cases, even abnormal unit shutdowns. Frequent oil changes and expensive additives increase the economic costs of the power industry. Replaced phosphate ester fire-resistant oil is classified as general hazardous waste, and improper disposal can pollute water sources and soil, causing harm to the environment. Summary of the Invention

[0011] To overcome the problems of existing technologies, this invention provides a phosphite-based composite additive and a highly stable phosphate ester fire-resistant oil, as well as its application. 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. Adding the phosphite-based composite additive to the phosphate ester fire-resistant oil can simultaneously improve the antioxidant and hydrolysis resistance of the phosphate ester fire-resistant oil, enhance the stability of the phosphate ester fire-resistant oil product, and provide a guarantee for the safe operation of generator sets.

[0012] To achieve the above objectives, 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, by weight fraction, the dosage 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 dosage of 2,6-di-tert-butyl-p-cresol accounts for 0.01% to 0.10% of the phosphate ester fire-resistant oil, and the dosage of Revonox 501 accounts for 0.0020% to 0.0050% of the phosphate ester fire-resistant oil.

[0014] Furthermore, the main component of the phosphate ester fire-resistant oil is tris(2,4-dimethyl)phosphate.

[0015] The present invention also provides a highly stable phosphate ester fire-resistant oil, wherein a phosphite-based composite additive is added to the phosphate ester fire-resistant oil, the composite additive being 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 specific dosage of the phosphite-based composite additive in the phosphate ester fire-resistant oil is as follows: the dosage 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 dosage of 2,6-di-tert-butyl-p-cresol accounts for 0.01% to 0.10% of the phosphate ester fire-resistant oil; and the dosage of Revonox 501 accounts for 0.0020% to 0.0050% of the phosphate ester fire-resistant oil.

[0017] Furthermore, the main component of the phosphate ester fire-resistant oil is tris(2,4-dimethyl)phosphate.

[0018] This invention also provides a method for preparing a highly stable phosphate ester fire-resistant oil, the specific steps of which are as follows:

[0019] S1 determines the dosage of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol, and Revonox 501 based on the total amount of oil. The bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol, and Revonox 501 are dissolved in new phosphate ester fire-resistant oil to obtain phosphite-based composite additive mother liquor.

[0020] Under the S2 sealed condition, the composite additive mother liquor is added to the phosphate ester fire-resistant oil.

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

[0022] This invention also provides an application of highly stable phosphate ester fire-resistant oil in the speed control system of a power plant turbine.

[0023] This invention also provides an application of highly stable phosphate ester fire-resistant oil in the speed control system of a gas turbine in a power plant.

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

[0025] This 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 overall performance of phosphate ester fire-resistant oil. The phosphite-based composite additive of this invention not only improves the oxidation stability of phosphate ester fire-resistant oil but also enhances its hydrolytic stability. This means that the fire-resistant oil maintains good performance stability under various operating conditions. Furthermore, the amount of the phosphite-based composite additive of this invention is small, yet the effect is significant, resulting in relatively low overall cost while achieving highly efficient performance improvement.

[0026] This invention provides a highly stable phosphate ester fire-resistant oil. The addition of a phosphite-based composite additive enhances both its antioxidant and hydrolysis resistance, meaning the fire-resistant oil can maintain its performance for a longer period, reducing maintenance and replacement costs due to performance degradation. By slowing the rate of acid value increase and resistivity decrease, and extending the operating time before sludge formation, this invention significantly extends the service life of phosphate ester fire-resistant oil. This is particularly important for large equipment requiring long-term stable operation (such as power plant turbines and gas turbines). The stable operation of phosphate ester fire-resistant oil directly affects the reliability and safety of equipment (such as speed control systems). Using the highly stable phosphate ester fire-resistant oil of this invention can improve the overall operational reliability of equipment and reduce downtime and failures caused by oil quality issues.

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

[0028] The highly stable phosphate ester fire-resistant oil of this invention is applicable to various equipment such as steam turbine speed control systems and gas turbine speed control systems in power plants, exhibiting wide applicability. Using highly stable phosphate ester fire-resistant oil can reduce equipment failures and downtime caused by oil quality issues, thereby improving the power generation efficiency and economic benefits of power plants. Furthermore, by extending the service life of the fire-resistant oil and reducing replacement frequency and waste generation, the application of this invention also has the advantages of environmental protection and energy conservation.

[0029] In summary, the method for adding the phosphite-based composite additive of this invention is simple. After addition, it can improve the oxidation stability and hydrolysis stability of phosphate ester fire-resistant oil, enhance the stability of acid value, resistivity and sludge precipitation during the use of phosphate ester fire-resistant oil, reduce the rate of increase in acid value and decrease in resistivity of phosphate ester fire-resistant oil products, extend its operating time before sludge formation, and thus extend the service life of phosphate ester fire-resistant oil. Moreover, it is inexpensive, has a simple addition method, and has high economic and social value. Detailed Implementation

[0030] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.

[0032] Unless otherwise specified, all the technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0033] In this invention, unless otherwise specified, percentage (%) or parts refer to weight percentage or parts relative to the composition.

[0034] Unless otherwise specified, the components or preferred components involved in this invention can be combined with each other to form new technical solutions.

[0035] In this invention, unless otherwise specified, the numerical range "a~b" represents an abbreviation of any combination of real numbers between a and b, where a and b are both 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 simply an abbreviation of these numerical combinations.

[0036] The "scope" disclosed in this invention can be in the form of a lower limit and an upper limit, and can be one or more lower limits and one or more upper limits, respectively.

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

[0038] In this invention, unless otherwise stated, the various reactions or operation steps may be performed sequentially or in a particular order. Preferably, the reaction methods described herein are performed sequentially.

[0039] Unless otherwise stated, the technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods or materials similar to or equivalent to those described herein may also be used in this invention.

[0040] This 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 above three additives are mixed to obtain the phosphite-based composite additive. This phosphite-based composite additive can be used to improve the overall performance of phosphate ester fire-resistant oil. The main component of the phosphate ester fire-resistant oil mentioned here is tris(2,6-methyl)phosphite.

[0041] Preferably, by weight percentage, the dosage of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite is 0.0020% to 0.0100% of the phosphate fire-resistant oil, the dosage of 2,6-di-tert-butyl-p-cresol is 0.01% to 0.10% of the phosphate fire-resistant oil, and the dosage 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 Glassware Reagent and Electronic Equipment Co., Ltd., with analytical purity, and is a phosphite antioxidant.

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

[0044] The present invention also provides a highly stable phosphate ester fire-resistant oil, the specific steps of which are as follows:

[0045] 1) Determine the amount of phosphate ester fire-resistant oil used, and obtain the dosage of phosphite-based composite additives based on the amount of phosphate ester fire-resistant oil used.

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

[0047] 3) At 60℃±5℃, under closed conditions, bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol and Revonox 501 were dissolved in the composite additive mother liquor solvent.

[0048] 4) Under sealed conditions, the composite additive mother liquor is added to the phosphate ester fire-resistant oil to obtain highly stable phosphate ester fire-resistant oil.

[0049] Example 1

[0050] A test sample of high-stability phosphate ester fire-resistant oil No. 1 was prepared, and a full analysis was performed on the test sample of high-stability phosphate ester fire-resistant oil No. 1 and the phosphate ester fire-resistant oil:

[0051] I. The test sample for No. 1 high-stability phosphate ester fire-resistant oil was prepared as follows:

[0052] 1) Select a phosphate ester fire-resistant oil whose main component is tris(2,4-dimethyl)phosphate. Take a sample bottle equipped with a sealing stopper, weigh a certain amount of phosphate ester fire-resistant oil into the sample bottle, calculate the mass of each additive based on the mass of the phosphate ester fire-resistant oil in the sample bottle, weigh it with an analytical balance and add it to the corresponding sample bottle, then seal the bottle with the cap.

[0053] The phosphite-based composite additive includes, 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 sample bottle has a volume of 1000 mL, and the sample bottle stopper is a polytetrafluoroethylene (PTFE) stopcock.

[0055] 2) Place the sealed sample vials on the mixing device, which includes a vertically arranged triangular support. The bottom of the triangular support is fixed in the drying oven, and a motor is installed on the top of the triangular support. The motor shaft is detachably connected to the sample vial fixing plate. When the motor shaft is connected to the sample vial fixing plate, the sample vial fixing plate is driven by the motor to achieve continuous vertical rotation at a speed of 5 r / min to 10 r / min. Multiple sample vial fixing clamps are arranged along the circumference of the sample vial fixing plate to fix the mouths of multiple sample vials toward the center of the sample vial fixing plate.

[0056] Preferably, the sample bottle fixing clamp includes 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 holder plate containing the sample bottle to the motor shaft. Keep the temperature in the drying oven constant at 60℃±5℃. Rotate the sample bottle holder plate to mix the sample for 1 hour to ensure that the additive dissolves in the phosphate ester fire-resistant oil and is mixed evenly.

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

[0059] II. The specific details of the full analysis and testing are as follows:

[0060] To test the actual effect of the phosphite-based composite additive of the present invention in improving phosphate ester fire-resistant oil after being added to phosphate ester fire-resistant oil, a full analysis was performed on the test samples of phosphate ester fire-resistant oil and No. 1 high-stability phosphate ester fire-resistant oil. The test results are shown in Table 1.

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

[0062]

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

[0064] When the compound additive combination does not contain bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, the oxidation stability 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 increased to 0.04 mg (KOH) / g, an increase of up to 60%.

[0065] The preferred method for detecting hydrolytic stability used in the full analytical testing is as follows:

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

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

[0068] 3) Separate the mixture of hydrolyzed phosphate fire-resistant oil and water to obtain a hydrolyzed phosphate fire-resistant oil layer and a water layer, and test the acid value A1 of the hydrolyzed phosphate fire-resistant oil layer and the acid value a1 of the water layer respectively.

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

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

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

[0072] Example 2

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

[0074] Table 2. Test results of base oil samples after adding compound additives.

[0075]

[0076]

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

[0078] Example 3

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

[0080] Table 3. Test results of base oil samples after adding compound additives.

[0081]

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

[0083] Example 4

[0084] Unlike Example 1, commercially available TURBOFLUID 46SJ phosphate fire-resistant oil was selected. The added phosphite-based composite additives included: 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. This yielded sample No. 4, a high-stability phosphate fire-resistant oil. The test results of key indicators are shown in Table 4.

[0085] Table 4. Test results of base oil samples after adding compound additives

[0086]

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

[0088] In summary, the phosphite-based composite additive of the present invention specifically comprises bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol, and Revonox. The mixture of 501, wherein the dosage of the additives 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 Revonox 501; when the three additives are used together, they exhibit a significant synergistic effect. The addition method is simple. After addition, it can improve the oxidation stability and hydrolytic stability of phosphate ester fire-resistant oil, enhance the stability of acid value, resistivity and sludge precipitation during the use of phosphate ester fire-resistant oil, reduce the rate of increase in acid value and decrease in resistivity of phosphate ester fire-resistant oil products, extend the running time before sludge formation, and thus extend the service life of phosphate ester fire-resistant oil. Moreover, it is inexpensive, the addition method is simple, and it has high economic and social value.

Claims

1. A highly stable phosphate ester fire-resistant oil, characterized in that, It is composed of a base oil and a phosphite-based composite additive added to the base oil. The base oil is tris(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, and 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. The specific addition amounts are as follows: bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite is added at a rate of 0.0020% to 0.0100% of the base oil, 2,6-di-tert-butyl-p-cresol is added at a rate of 0.01% to 0.10% of the base oil, and Revonox 501 is added at a rate of 0.0020% to 0.0050% of the base oil.

2. The method for preparing a highly stable phosphate ester fire-resistant oil according to claim 1, characterized in that, The specific steps are as follows: S1: Determine the dosage of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol, and Revonox 501 based on the total amount of oil. Dissolve bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol, and Revonox 501 in the base oil to obtain a phosphite-based composite additive mother liquor. S2: Under sealed conditions, add the composite additive mother liquor to the phosphate ester fire-resistant oil.

3. The method for preparing a highly stable phosphate ester fire-resistant oil according to claim 2, characterized in that, In S1, under closed conditions at 60℃±5℃, bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol and Revonox 501 are dissolved in base oil and mixed to obtain a phosphite-based composite additive mother liquor.

4. The application of the high-stability phosphate ester fire-resistant oil as described in claim 1 in the turbine speed control system of a power plant.

5. The application of the high-stability phosphate ester fire-resistant oil as described in claim 1 in the speed regulation system of a gas turbine in a power plant.

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