Method for evaluating service life of steam turbine oil

Abstract

The invention relates to a steam turbine oil service life evaluation method which comprises the following steps: placing steam turbine oil to be evaluated in a steam turbine oil service life evaluation device for regular sampling detection to obtain basic data; key indexes used for evaluating the service life of the steam turbine oil are screened out from the basic data based on the oxidative degradation theory; establishing an oxidative degradation rate equation of the key indexes according to an evolution rule of the key indexes; combining the oxidative degradation rate equation of the key index with an Arrhenius oxidation kinetic equation, and establishing a steam turbine oil life evaluation model taking the key index as an evaluation index; and analyzing the evaluation result of the steam turbine oil life evaluation model taking the key index as the evaluation index through a multi-level analysis method, and establishing a multi-evaluation steam turbine oil life prediction model based on the analysis result, so as to evaluate and predict the life of the steam turbine oil at any temperature. The method is high in accuracy of evaluating the service life of the steam turbine oil.

Description

Technical Field

[0001] The invention belongs to the field of turbine oil, and in particular relates to a method for evaluating the life of turbine oil. Background Art

[0002] Steam turbine oil is mainly used to lubricate the sliding bearings, reduction gears and speed governors of steam turbine generator sets and hydro-turbine generator sets, and is also used as the working medium of the hydraulic system. Since these units have large oil tanks and use a lot of oil, the cost of replacing the oil is high. Therefore, formulating a reasonable oil change cycle is of great significance to ensure the safe operation of the unit and reduce costs.

[0003] At present, in the process of oil monitoring, we usually rely on experience and standards to monitor parameters such as acid value, moisture, pour point, flash point, kinematic viscosity, rotating oxygen bomb, antioxidant content, film tendency index and contamination to evaluate the oil quality and service life of turbine oil. However, some conventional parameters change little, while oxidation index is the key factor in turbine oil deterioration. Therefore, the mechanism analysis method is used to screen out the key physical and chemical indicators that affect turbine oil deterioration, which can not only save the detection cost, but also improve the pertinence and efficiency of the detection. This method avoids unnecessary detection of those physical and chemical indicators with less impact, thereby significantly improving the accuracy and reliability of the evaluation.

[0004] At the same time, the existing turbine oil life assessment method mainly uses oven aging tests to evaluate the changes in physical and chemical indicators of oil products after aging, but this method ignores the oxidation degradation of oil products during actual equipment use and lacks mechanism explanation and the establishment of oxidation degradation models. Therefore, this method may not be able to accurately assess the life of turbine oil.

[0005] Therefore, the present invention provides a method for evaluating the life of turbine oil to solve the shortcomings of traditional evaluation methods and provide a more accurate theoretical basis for evaluating the life of turbine oil. Summary of the invention

[0006] The present invention provides a method for evaluating the life of a steam turbine oil, comprising the following steps:

[0007] S1, placing the turbine oil to be evaluated in a turbine oil life evaluation device for regular sampling and testing to obtain basic data;

[0008] S2, based on the oxidation degradation theory, selecting key indicators for evaluating the life of turbine oil from the basic data, wherein the key indicators include kinematic viscosity, acid value, oxidation value, antioxidant content, film tendency index and rotating oxygen bomb;

[0009] S3, according to the evolution law of the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the paint film tendency index and the rotating oxygen bomb, respectively establish the oxidative degradation rate equations of the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the paint film tendency index and the rotating oxygen bomb;

[0010] S4, combining the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the paint film tendency index and the oxidation degradation rate equation of the rotating oxygen bomb with the Arrhenius oxidation kinetic equation, respectively, to establish a turbine oil life assessment model using the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the paint film tendency index and the rotating oxygen bomb as evaluation indicators;

[0011] S5, analyzing the evaluation results of the turbine oil life evaluation model using the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the varnish tendency index and the rotating oxygen bomb as evaluations through a multi-level analysis method, and establishing a multi-evaluation turbine oil life prediction model based on the analysis results to achieve evaluation and prediction of the life of the turbine oil at any temperature.

[0012] 5. Preferably, the formula of the oxidative degradation rate equation of the kinematic viscosity is: Ly = L y0 exp(k y t y ), the equation for logarithmic transformation of the oxidative degradation rate equation of kinematic viscosity is: Among them, L y0 is the new oil value of the kinematic viscosity index at room temperature, Ly is the value of the kinematic viscosity index at a certain test time; k y is the oxidative degradation rate of the kinematic viscosity; t y is the life of the turbine oil estimated by the kinematic viscosity index;

[0013] The formula of the oxidation degradation rate equation of the acid value is: Ls = L s0 exp(k s t s ), the oxidation degradation rate equation of the acid value is logarithmically transformed as follows: Among them, L s0 is the new oil value of the acid value index at room temperature, L s k is the value of the acid value index at a certain test time; s is the acid value oxidation degradation rate; t s is the life of the steam turbine oil estimated by the acid value index;

[0014] The oxidation degradation rate equation of the oxidation value is: Lo = Lo0 exp(k o t o ), the oxidation degradation rate equation of the acid value is logarithmically transformed as follows: Among them, L o0 is the new oil value of the acid value index at room temperature, L o k is the value of the acid value index at a certain test time; o is the acid value oxidation degradation rate; t o is the life of the steam turbine oil estimated by the acid value index;

[0015] The formula of the oxidation degradation rate equation of the antioxidant content is: Lk = L k0 exp(k k t k ), the oxidation degradation rate equation of the antioxidant content is logarithmically transformed as follows: Among them, L k0 is the new oil value of the antioxidant content index at room temperature, L k k is the value of the antioxidant content index at a certain test time; k is the oxidative degradation rate of the antioxidant content; t k is the life of the steam turbine oil estimated by the antioxidant content index;

[0016] The formula of the oxidation degradation rate equation of the paint film tendency index is: Lq = L q0 exp(k q t q ), the oxidation degradation rate equation of the paint film tendency index is logarithmically transformed as follows: Among them, L q0 is the new oil value of the paint film tendency index at room temperature, L q k is the value of the paint film tendency index at a certain test time; q is the paint film tendency index oxidative degradation rate; t q is the life of the steam turbine oil estimated by the varnish tendency index;

[0017] The formula of the oxidation degradation rate equation of the rotating oxygen bomb is: Lx = L x0 exp(k x t x ), the equation for logarithmic transformation of the oxidation degradation rate equation of the rotating oxygen bomb is: Among them, L x0 is the new oil value of the rotating oxygen bomb index at room temperature, L x k is the value of the rotating oxygen bomb index at a certain test time; x is the oxidation degradation rate of the rotating oxygen bomb; tx is the turbine oil life estimated by the rotating oxygen bomb index.

[0018] Preferably, the turbine oil life assessment model using kinematic viscosity as an evaluation index is: The turbine oil life assessment model using the acid value as an evaluation index is: The turbine oil life assessment model using the oxidation value as an evaluation index is: The turbine oil life assessment model using the antioxidant content as an evaluation index is: The turbine oil life evaluation model using the paint film tendency index as an evaluation index is: The turbine oil life assessment model using the rotating oxygen bomb as an evaluation index is: Among them, A y , A s , A o , A k , A q , A x is the frequency factor; E y 、E s 、E o 、E k 、E q 、E x is the reaction activation energy; R y , R s , R o , R k , R q , R x is the gas constant, which is 8.314 J / (mol·K); T is the absolute temperature; L yfailure is the kinematic viscosity failure value, L sfailure is the acid failure value, L ofailure is the oxidation failure value, L kfailure is the antioxidant content failure value, L qfailure is the failure value of the paint film tendency index, L xfailure is the failure value of the rotating oxygen bomb; L y 0 is the oil value of the kinematic viscosity, L s 0 is the oil value of the acid value, L o 0 is the oil value of the oxidation value, L k 0 is the oil value of the antioxidant content, L q 0 is the oil value of the paint film tendency index, L x 0 is the oil value of the rotating oxygen bomb.

[0019] Preferably, the multi-evaluation turbine oil life prediction model is: z =P y ×t y+P s ×t s +P o ×t o +P q ×t q +P k ×t k +P x ×t x , wherein the P y is the weight of the kinematic viscosity; the P s is the weight of the acid value; s is the weight of the oxidation number; q is the weight of the paint film tendency index; P k is the weight of the antioxidant content; P x is the weight of the rotating oxygen bomb.

[0020] Preferably, the turbine oil life assessment device includes an oil filter, a one-way valve, a pressure gauge, a gear pump, a motor, a relief valve, a thermometer, a cooler, a thermostatic oil tank with adjustable temperature, and a hydraulic oil pipe connecting the above components; the oil filter is connected to the one-way valve through the hydraulic oil pipe, the one-way valve is connected to the pressure gauge and the gear pump at the same time through the hydraulic oil pipe, the gear pump is connected to the thermostatic oil tank with adjustable temperature through the hydraulic oil pipe, the thermostatic oil tank with adjustable temperature is connected to the cooler through the hydraulic oil pipe, the cooler is connected to the thermostat and the relief valve at the same time through the hydraulic oil pipe, and the motor is electrically connected to the gear pump.

[0021] Preferably, in S1, the turbine oil to be evaluated is sampled and tested regularly, specifically as follows: the temperature of the adjustable thermostatic oil tank is set to 80°C, the frequency of the regular sampling and testing is 3 days / time, and the cycle of the regular sampling and testing is 30 days; the temperature of the adjustable thermostatic oil tank is set to 100°C, the frequency of the regular sampling and testing is 2 days / time, and the cycle of the regular sampling and testing is 20 days; the temperature of the adjustable thermostatic oil tank is set to 120°C, the frequency of the regular sampling and testing is 1 day / time, and the cycle of the regular sampling and testing is 10 days.

[0022] Preferably, the kinematic viscosity is detected by a petroleum product kinematic viscosity determination method and a dynamic viscosity calculation method; the acid value is detected by a petroleum product acid value determination method; the oxidation value and the antioxidant content are detected by infrared spectroscopy; and the rotary oxygen bomb is detected by lubricating oil oxidation stability.

[0023] Compared with the related art, the present invention has the following beneficial effects:

[0024] 1. The turbine oil life evaluation device can simulate the oxidation degradation process of turbine oil in the circulating oil circuit, avoiding the problem that the traditional beaker thermal aging test only considers thermal oxidation and ignores the problem that the turbine oil may accelerate oxidation degradation in the circulating oil circuit.

[0025] 2. The temperature is adjusted by the thermostatic oil tank with adjustable temperature to accelerate the oxidation of the turbine oil, shorten the oil oxidation cycle, and realize the rapid evaluation of the turbine oil life.

[0026] 3. The kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the paint film tendency index and the oxidation degradation rate equation of the rotating oxygen bomb are respectively combined with the Arrhenius oxidation kinetic equation to realize the life evaluation of the turbine oil at any temperature, avoiding the problem of evaluating the life of the turbine oil at a certain operating temperature only through device tests.

[0027] 4. The present invention uses the oxidation degradation theory to effectively screen out key indicators for evaluating the life of turbine oil, thereby saving the testing cost and avoiding the testing of physical and chemical indicators with less impact. In addition, by comprehensively evaluating multiple evaluation indicators, the evaluation bias that may be caused by relying on only a single indicator is avoided, and the accuracy of the evaluation is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic flow chart of a method for evaluating the life of a steam turbine oil according to the present invention;

[0029] Figure 2 It is a schematic diagram of the structure of the device for evaluating the life of turbine oil according to the present invention. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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] Please also refer to the attached Figure 1-2 The present invention provides a method for evaluating the life of a steam turbine oil, comprising the following steps:

[0032] S1, placing the turbine oil to be evaluated in a turbine oil life evaluation device for regular sampling and testing to obtain basic data.

[0033] Specifically, the turbine oil life assessment device includes an oil filter 1, a one-way valve 2, a pressure gauge 3, a gear pump 4, a motor 5, a relief valve 6, a thermometer 8, a cooler 9, a thermostatic oil tank 10 with adjustable temperature, and a hydraulic oil pipe 7 connecting the above components; the oil filter 1 is connected to the one-way valve 2 through the hydraulic oil pipe 7, the one-way valve 2 is simultaneously connected to the pressure gauge 3 and the gear pump 4 through the hydraulic oil pipe 7, the gear pump 4 is connected to the thermostatic oil tank 10 with adjustable temperature through the hydraulic oil pipe 7, the thermostatic oil tank 10 with adjustable temperature is connected to the cooler 9 through the hydraulic oil pipe 7, the cooler 9 is simultaneously connected to the thermometer 8 and the relief valve 6 through the hydraulic oil pipe 7, and the motor 5 is electrically connected to the gear pump 4.

[0034] Further, in S1, according to the Van't Hoff law, the reaction rate increases with increasing temperature, and the reaction rate will increase exponentially for every 10-20K increase in reaction temperature. On this basis, this embodiment selects a certain brand of turbine oil as the turbine oil to be evaluated, and formulates three groups of test schemes for the turbine oil to be evaluated at different temperatures, including temperature, time period and sampling frequency, etc. The test scheme is shown in Table 1; then, the turbine oil to be evaluated is placed in the temperature-adjustable constant temperature oil tank 10, and is set to constant temperatures of 80°C, 100°C and 120°C respectively to operate the turbine oil life evaluation device. By testing the turbine oil life evaluation device at these different temperatures, the oxidation degradation behavior and life of the turbine oil can be more accurately evaluated.

[0035] Table 1

[0036] Test temperature / ℃ Test time period / day Sampling frequency / times 80 30 3 days 100 20 2 days 120 10 1 day

[0037] By starting the turbine oil life assessment device, the oxidation degradation process of the turbine oil in the circulating oil circuit at different temperatures can be simulated, and the temperature-adjustable constant temperature oil tank 10 can adjust the temperature change to accelerate the oxidation of the oil, shorten the oil oxidation cycle, and achieve a rapid assessment of the turbine oil life.

[0038] The turbine oil life evaluation device test is carried out according to the test plan. The turbine oil to be evaluated is extracted from the temperature-adjustable constant temperature oil tank 10 at preset time intervals, and the key indicators of the turbine oil to be evaluated are tested to monitor the oxidative degradation behavior of the oil product, thereby providing basic data for turbine oil life evaluation.

[0039] In addition, it should be noted that the complete process of the turbine oil life evaluation device for testing the turbine oil to be evaluated is as follows:

[0040] (1) An evaluation device for checking the life of the turbine oil:

[0041] Before starting the turbine oil life assessment device, it is necessary to correctly connect all pipelines and all wiring according to the schematic diagram, and check whether the hydraulic oil pipe is correctly matched and connected with the actuator.

[0042] (2) Add the turbine oil to be evaluated:

[0043] Add an appropriate amount of the turbine oil to be evaluated. The turbine oil to be evaluated must be kept clean. Use a refueling machine with a fine filter to inject it. When refueling, add it from the oil filter 1. Pay attention to the liquid level and add the required amount of oil. At the same time, observe the temperature-adjustable constant temperature oil tank 10 and the pipeline for oil leakage.

[0044] (3) Adjusting the temperature of the thermostatic oil tank 10 with adjustable temperature:

[0045] After adding a proper amount of the turbine oil to be evaluated, the temperature-adjustable constant temperature oil tank 10 is adjusted to a corresponding temperature, and after the temperature reaches a preset requirement, the cooler 9 is started.

[0046] (4) Starting the turbine oil life assessment device:

[0047] After the temperature of the turbine oil to be evaluated reaches the preset requirement, the turbine oil life evaluation device is started. Before starting the turbine oil life evaluation device, it is necessary to check again whether the pipeline is connected properly; jog the gear pump 4 and the motor 5 to observe whether the direction of the motor 5 is correct. If not, adjust the motor 5 connection to ensure the correct direction of the motor 5; jog the motor 3 to 5 times so that the gear pump 4 can fully absorb the oil, and then start the motor 5 normally to make the turbine oil life evaluation device operate normally.

[0048] (5) Regular sampling and testing:

[0049] During the normal operation of the turbine oil life assessment device, the turbine oil to be assessed in the temperature-adjustable constant temperature oil tank 10 is sampled and tested regularly according to a preset sampling frequency to establish basic data.

[0050] S2, based on the oxidation degradation theory, the key indicators for evaluating the life of turbine oil are screened out from the basic data, and the key indicators include kinematic viscosity, acid value, oxidation value, antioxidant content, varnish tendency index and rotating oxygen bomb.

[0051] In this embodiment, according to the oxidation degradation theory, a series of chain reactions will occur during the degradation process of the turbine oil to be evaluated, forming vapor-phase evaporated oil and products of low relative molecular mass. Subsequently, the oxidation products of low relative molecular mass evaporate to form gas-phase products, such as ketones, aldehydes, alcohols and acids. The remaining oxidation free radical byproducts polymerize into oxidation products of high relative molecular mass, and finally form oxidation degradation products such as sludge and paint film. Based on this, kinematic viscosity, acid value, oxidation value, antioxidant content, paint film tendency index and rotating oxygen bomb are screened as key indicators for turbine oil life evaluation.

[0052] It is worth mentioning that the kinematic viscosity is detected by GB / T 265 petroleum product kinematic viscosity determination method and dynamic viscosity calculation method; the acid value is detected by GB / T 264 petroleum product acid value determination method; the oxidation value and the antioxidant content are detected by infrared spectroscopy; the rotating oxygen bomb is detected by SH / T 0193-2008 lubricant oxidation stability; the paint film tendency index is detected by ASTM D7843-2012 Standard Test Method for Mesurement of Lubricant Generated Insoluble Color Bodies in In-Service Turbine Oils using Membrane Patch Colorimetry.

[0053] S3, according to the evolution law of the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the paint film tendency index and the rotating oxygen bomb, establish the oxidative degradation rate equations of the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the paint film tendency index and the rotating oxygen bomb respectively.

[0054] In this embodiment, based on the evolution law of the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the paint film tendency index and the rotating oxygen bomb over the test time, the first-order integral rate equation is used to establish the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the paint film tendency index and the oxidation degradation rate equation of the rotating oxygen bomb, and the oxidation rate at a certain temperature is obtained by solving the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the paint film tendency index and the oxidation degradation rate equation of the rotating oxygen bomb. The specific formula is as follows:

[0055] The formula of the oxidative degradation rate equation of the kinematic viscosity is: Ly = L y0 exp(k y t y), the equation for logarithmic transformation of the oxidative degradation rate equation of kinematic viscosity is: Among them, L y0 is the new oil value of the kinematic viscosity index at room temperature, Ly is the value of the kinematic viscosity index at a certain test time; k y is the oxidative degradation rate of the kinematic viscosity; t y is the life of the turbine oil estimated by the kinematic viscosity index;

[0056] The formula of the oxidation degradation rate equation of the acid value is: Ls = L s0 exp(k s t s ), the oxidation degradation rate equation of the acid value is logarithmically transformed as follows: Among them, L s0 is the new oil value of the acid value index at room temperature, L s k is the value of the acid value index at a certain test time; s is the acid value oxidation degradation rate; t s is the life of the steam turbine oil estimated by the acid value index;

[0057] The oxidation degradation rate equation of the oxidation value is: Lo = L o0 exp(k o t o ), the oxidation degradation rate equation of the acid value is logarithmically transformed as follows: Among them, L o0 is the new oil value of the acid value index at room temperature, L o k is the value of the acid value index at a certain test time; o is the acid value oxidation degradation rate; t o is the life of the steam turbine oil estimated by the acid value index;

[0058] The formula of the oxidation degradation rate equation of the antioxidant content is: Lk = L k0 exp(k k t k ), the oxidation degradation rate equation of the antioxidant content is logarithmically transformed as follows: Among them, L k0 is the new oil value of the antioxidant content index at room temperature, L k k is the value of the antioxidant content index at a certain test time; k is the oxidative degradation rate of the antioxidant content; t k is the life of the steam turbine oil estimated by the antioxidant content index;

[0059] The formula of the oxidation degradation rate equation of the paint film tendency index is: Lq = L q0 exp(k q t q ), the oxidation degradation rate equation of the paint film tendency index is logarithmically transformed as follows: Among them, L q0 is the new oil value of the paint film tendency index at room temperature, L q k is the value of the paint film tendency index at a certain test time; q is the paint film tendency index oxidative degradation rate; t q is the life of the steam turbine oil estimated by the varnish tendency index;

[0060] The formula of the oxidation degradation rate equation of the rotating oxygen bomb is: Lx = L x0 exp(k x t x ), the equation for logarithmic transformation of the oxidation degradation rate equation of the rotating oxygen bomb is: Among them, L x0 is the new oil value of the rotating oxygen bomb index at room temperature, L x k is the value of the rotating oxygen bomb index at a certain test time; x is the oxidation degradation rate of the rotating oxygen bomb; t x is the turbine oil life estimated by the rotating oxygen bomb index.

[0061] S4, combining the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the paint film tendency index and the oxidation degradation rate equation of the rotating oxygen bomb with the Arrhenius oxidation kinetic equation, and establishing a turbine oil life assessment model with the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the paint film tendency index and the rotating oxygen bomb as evaluation indicators.

[0062] In this embodiment, the Arhenius oxidation kinetic equation is: Among them, A is the frequency factor; E is the reaction activation energy; R is the gas constant, R = 8.314 J / (mol·K); T is the absolute temperature, and K is the oxidation rate.

[0063] The kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the paint film tendency index and the oxidation degradation rate equation of the rotating oxygen bomb are respectively combined with the Arrhenius oxidation kinetic equation to obtain the following turbine oil life assessment model:

[0064] The turbine oil life evaluation model using kinematic viscosity as an evaluation index is: The turbine oil life assessment model using the acid value as an evaluation index is: The turbine oil life assessment model using the oxidation value as an evaluation index is: The turbine oil life assessment model using the antioxidant content as an evaluation index is: The turbine oil life evaluation model using the paint film tendency index as an evaluation index is: The turbine oil life assessment model using the rotating oxygen bomb as an evaluation index is: Among them, A y , A s , A o , A k , A q , A x is the frequency factor; E y 、E s 、E o 、E k 、E q 、E x is the reaction activation energy; R y , R s , R o , R k , R q , R x is the gas constant, which is 8.314 J / (mol·K); T is the absolute temperature; L yfailure is the kinematic viscosity failure value, L sfailure is the acid failure value, L ofailure is the oxidation failure value, L kfailure is the antioxidant content failure value, L qfailure is the failure value of the paint film tendency index, L xfailure is the failure value of the rotating oxygen bomb; L y 0 is the oil value of the kinematic viscosity, L s 0 is the oil value of the acid value, L o 0 is the oil value of the oxidation value, L k 0 is the oil value of the antioxidant content, L q 0 is the oil value of the paint film tendency index, L x 0 is the oil value of the rotating oxygen bomb.

[0065] In the above model, according to the standard NB / SH / T 0636L-TSA turbine oil change index, the failure value of kinematic viscosity is more than ±10% of new oil; the failure value of acid value is more than 0.3mgKOH / g; the failure value of rotating oxygen bomb is less than 25% of new oil. The failure thresholds of oxidation value, antioxidant content and film tendency index need to be formulated during the test process.

[0066] S5, analyzing the evaluation results of the turbine oil life evaluation model using the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the varnish tendency index and the rotating oxygen bomb as evaluations through a multi-level analysis method, and establishing a multi-evaluation turbine oil life prediction model based on the analysis results to achieve evaluation and prediction of the life of the turbine oil at any temperature.

[0067] In this embodiment, the multi-evaluation turbine oil life prediction model is: z =P y ×t y +P s ×t s +P o ×t o +P q ×t q +P k ×t k +P x ×t x , wherein the P y is the weight of the kinematic viscosity; the P s is the weight of the acid value; s is the weight of the oxidation number; q is the weight of the paint film tendency index; P k is the weight of the antioxidant content; x is the weight of the rotating oxygen bomb.

[0068] Furthermore, the importance of the evaluation results of the turbine oil life evaluation model using the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the varnish tendency index and the rotating oxygen bomb as evaluations is determined by the analytic hierarchy process, and the corresponding weights are calculated; then, the weights are assigned to the corresponding single evaluation index life evaluation model to establish a highly reliable multi-evaluation turbine oil life prediction model. The steps for determining the weights by the analytic hierarchy process are as follows:

[0069] First, the hierarchical structure is determined and divided into two layers: the target layer and the factor layer. The target layer is "the importance of the evaluation results of the turbine oil life evaluation model of the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the lacquer tendency index and the rotating oxygen bomb", and the factor layer is "kinematic viscosity", "acid value", "oxidation value", "lacquer tendency index", "antioxidant content" and "rotating oxygen bomb".

[0070] Then, a judgment matrix is ​​established to measure the relative importance of the two indicators. The matrix is ​​tested for consistency and the weights of different evaluation indicators are obtained: the weight of kinematic viscosity is Py, the weight of acid value is Ps, the weight of oxidation value is Po, the weight of film tendency index is Pq, the weight of antioxidant content is Pk and the weight of rotating oxygen bomb is Px. Based on the weights of different evaluation indicators, a multi-evaluation turbine oil life prediction model is established.

[0071] Compared with the related art, the present invention has the following beneficial effects:

[0072] 1. The turbine oil life evaluation device can simulate the oxidation degradation process of turbine oil in the circulating oil circuit, avoiding the problem that the traditional beaker thermal aging test only considers thermal oxidation and ignores the problem that the turbine oil may accelerate oxidation degradation in the circulating oil circuit.

[0073] 2. The temperature is adjusted by the thermostatic oil tank with adjustable temperature to accelerate the oxidation of the turbine oil, shorten the oil oxidation cycle, and realize the rapid evaluation of the turbine oil life.

[0074] 3. The kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the paint film tendency index and the oxidation degradation rate equation of the rotating oxygen bomb are respectively combined with the Arrhenius oxidation kinetic equation to realize the life evaluation of the turbine oil at any temperature, avoiding the problem of evaluating the life of the turbine oil at a certain operating temperature only through device tests.

[0075] 4. The present invention uses the oxidation degradation theory to effectively screen out key indicators for evaluating the life of turbine oil, thereby saving the testing cost and avoiding the testing of physical and chemical indicators with less impact. In addition, by comprehensively evaluating multiple evaluation indicators, the evaluation bias that may be caused by relying on only a single indicator is avoided, and the accuracy of the evaluation is improved.

[0076] It should be noted that the above-described embodiments should be understood as illustrative rather than limiting the scope of protection of the present invention, and the scope of protection of the present invention shall be subject to the claims. For those skilled in the art, some non-essential improvements and adjustments made to the present invention still fall within the scope of protection of the present invention without departing from the essence and scope of the present invention.

Claims

1. A method for evaluating the life of a steam turbine oil, characterized in that: The method comprises the following steps: S1, placing the turbine oil to be evaluated in a turbine oil life evaluation device for regular sampling and testing to obtain basic data; S2, based on the oxidation degradation theory, selecting key indicators for evaluating the life of turbine oil from the basic data, wherein the key indicators include kinematic viscosity, acid value, oxidation value, antioxidant content, film tendency index and rotating oxygen bomb; S3, according to the evolution law of the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the paint film tendency index and the rotating oxygen bomb, respectively establish the oxidative degradation rate equations of the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the paint film tendency index and the rotating oxygen bomb; S4, combining the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the paint film tendency index and the oxidation degradation rate equation of the rotating oxygen bomb with the Arrhenius oxidation kinetic equation, respectively, to establish a turbine oil life assessment model using the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the paint film tendency index and the rotating oxygen bomb as evaluation indicators; S5, analyzing the evaluation results of the turbine oil life evaluation model using the kinematic viscosity, the acid value, the oxidation value, the antioxidant content, the varnish tendency index and the rotating oxygen bomb as evaluations through a multi-level analysis method, and establishing a multi-evaluation turbine oil life prediction model based on the analysis results to achieve evaluation and prediction of the life of the turbine oil at any temperature.

2. A method for evaluating the life of a steam turbine oil according to claim 1, characterized in that: The formula of the oxidative degradation rate equation of the kinematic viscosity is: Ly = L y0 exp(k y t y ), the equation for logarithmic transformation of the oxidative degradation rate equation of kinematic viscosity is: Among them, L y0 is the new oil value of the kinematic viscosity index at room temperature, Ly is the value of the kinematic viscosity index at a certain test time; k y is the oxidative degradation rate of the kinematic viscosity; t y is the life of the turbine oil estimated by the kinematic viscosity index; The formula of the oxidation degradation rate equation of the acid value is: Ls = L s0 exp(k s t s ), the oxidation degradation rate equation of the acid value is logarithmically transformed as follows: Among them, L s0 is the new oil value of the acid value index at room temperature, L s k is the value of the acid value index at a certain test time; s is the acid value oxidation degradation rate; t s is the life of the steam turbine oil estimated by the acid value index; The oxidation degradation rate equation of the oxidation value is: Lo = L o0 exp(k o t o ), the oxidation degradation rate equation of the acid value is logarithmically transformed as follows: Among them, L o0 is the new oil value of the acid value index at room temperature, L o k is the value of the acid value index at a certain test time; o is the acid value oxidation degradation rate; t o is the life of the steam turbine oil estimated by the acid value index; The formula of the oxidation degradation rate equation of the antioxidant content is: Lk = L k0 exp(k k t k ), the oxidation degradation rate equation of the antioxidant content is logarithmically transformed as follows: Among them, L k0 is the new oil value of the antioxidant content index at room temperature, L k k is the value of the antioxidant content index at a certain test time; k is the oxidative degradation rate of the antioxidant content; t k The life of the steam turbine oil estimated by the antioxidant content index; The formula of the oxidation degradation rate equation of the paint film tendency index is: Lq = L q0 exp(k q t q ), the oxidation degradation rate equation of the paint film tendency index is logarithmically transformed as follows: Among them, L q0 is the new oil value of the paint film tendency index at room temperature, L q k is the value of the paint film tendency index at a certain test time; q is the paint film tendency index oxidation degradation rate; t q is the life of the steam turbine oil estimated by the varnish tendency index; The formula of the oxidation degradation rate equation of the rotating oxygen bomb is: Lx = L x0 exp(k x t x ), the equation for logarithmic transformation of the oxidation degradation rate equation of the rotating oxygen bomb is: Among them, L x0 is the new oil value of the rotating oxygen bomb index at room temperature, L x k is the value of the rotating oxygen bomb index at a certain test time; x is the oxidation degradation rate of the rotating oxygen bomb; t x is the turbine oil life estimated by the rotating oxygen bomb index.

3. A method for evaluating the life of a steam turbine oil according to claim 2, characterized in that: The turbine oil life evaluation model using kinematic viscosity as an evaluation index is: The turbine oil life assessment model using the acid value as an evaluation index is: The turbine oil life assessment model using the oxidation value as an evaluation index is: The turbine oil life assessment model using the antioxidant content as an evaluation index is: The turbine oil life evaluation model using the paint film tendency index as an evaluation index is: The turbine oil life assessment model using the rotating oxygen bomb as an evaluation index is: Among them, A y , A s , A o , A k , A q , A x is the frequency factor; E y 、E s 、E o 、E k 、E q 、E x is the reaction activation energy; R y , R s , R o , R k , R q , R x is the gas constant, which is 8.314 J / (mol·K); T is the absolute temperature; L yfailure is the kinematic viscosity failure value, L sfailure is the acid failure value, L ofailure is the oxidation failure value, L kfailure is the antioxidant content failure value, L qfailure is the failure value of the paint film tendency index, L xfailure is the failure value of the rotating oxygen bomb; L y 0 is the oil value of the kinematic viscosity, L s 0 is the oil value of the acid value, L o 0 is the oil value of the oxidation value, L k 0 is the oil value of the antioxidant content, L q 0 is the oil value of the paint film tendency index, L x 0 is the oil value of the rotating oxygen bomb.

4. A method for evaluating the life of a steam turbine oil according to claim 3, characterized in that: The multi-evaluation turbine oil life prediction model is: z =P y ×t y +P s ×t s +P o ×t o +P q ×t q +P k ×t k +P x ×t x , wherein the P y is the weight of the kinematic viscosity; the P s is the weight of the acid value; s is the weight of the oxidation number; q is the weight of the paint film tendency index; P k is the weight of the antioxidant content; x is the weight of the rotating oxygen bomb.

5. The method for evaluating the life of a steam turbine oil according to claim 1, characterized in that: The device for evaluating the life of turbine oil includes an oil filter, a one-way valve, a pressure gauge, a gear pump, a motor, a relief valve, a thermometer, a cooler, a thermostatic oil tank with adjustable temperature, and a hydraulic oil pipe connecting the above components; the oil filter is connected to the one-way valve through the hydraulic oil pipe, the one-way valve is connected to the pressure gauge and the gear pump at the same time through the hydraulic oil pipe, the gear pump is connected to the thermostatic oil tank with adjustable temperature through the hydraulic oil pipe, the thermostatic oil tank with adjustable temperature is connected to the cooler through the hydraulic oil pipe, the cooler is connected to the thermometer and the relief valve at the same time through the hydraulic oil pipe, and the motor is electrically connected to the gear pump.

6. A method for evaluating the life of a steam turbine oil according to claim 5, characterized in that: In S1, the turbine oil to be evaluated is sampled and tested regularly, specifically as follows: the temperature of the adjustable thermostatic oil tank is set to 80°C, the frequency of the regular sampling and testing is 3 days / time, and the period of the regular sampling and testing is 30 days; the temperature of the adjustable thermostatic oil tank is set to 100°C, the frequency of the regular sampling and testing is 2 days / time, and the period of the regular sampling and testing is 20 days; the temperature of the adjustable thermostatic oil tank is set to 120°C, the frequency of the regular sampling and testing is 1 day / time, and the period of the regular sampling and testing is 10 days.

7. A method for evaluating the life of a steam turbine oil according to claim 1, characterized in that: The kinematic viscosity is detected by the petroleum product kinematic viscosity determination method and the dynamic viscosity calculation method; the acid value is detected by the petroleum product acid value determination method; the oxidation value and the antioxidant content are detected by infrared spectroscopy; the rotary oxygen bomb is detected by the lubricating oil oxidation stability.

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