Performance test method for high-precision filtration of turbine oil

Abstract

The application discloses a kind of turbine oil high-precision oil filter performance test method, more specifically related to lubricating oil testing technical field, including S1, construct closed loop test system and prepare reference oil sample, S2, programed collaborative injection solid particles and soluble colloidal contaminant, to simulate dynamic pollution load, S3, run the multi-stage composite operating condition cycle including high temperature and high flow, rapid cooling, pressure fluctuation and high temperature and low pressure stage, and real-time monitoring filter oil upstream and downstream particle distribution, moisture and pressure difference, S4, test continues until reaching any one of composite termination conditions based on pressure difference exceeding standard, filtration ratio drops or oil key performance degradation, S5, generate comprehensive report containing dynamic dust capacity, efficiency curve, performance influence coefficient and simulation life.The application can more truly and comprehensively evaluate the comprehensive performance and long-term reliability of filter oil.

Description

Technical Field

[0001] This invention relates to the field of lubricating oil testing technology, and more specifically, to a performance testing method for high-precision turbine oil filtration. Background Technology

[0002] The cleanliness of the turbine oil system is crucial for ensuring the safe, stable, and long-term operation of large rotating equipment. High-precision oil filters, also known as high-precision oil filters, are core components for maintaining oil cleanliness. Their performance directly affects the reliability and lifespan of the unit. Therefore, accurate and reliable performance testing and evaluation of high-precision oil filters are key aspects of equipment operation and maintenance and oil filter selection.

[0003] Currently, the testing and evaluation methods for oil filter performance are mainly based on the international standard ISO 16889 "Hydraulic transmission - Filters - Determination of filtration characteristics by multiple pass method" or a simplified single pass method based on similar principles. These methods evaluate the filtration efficiency and dirt holding capacity by testing the filtration ratio and dust holding capacity of the oil to standard test dust under constant flow rate, temperature and contaminant injection rate.

[0004] However, current testing methods have the following drawbacks: static testing cannot simulate actual dynamic working conditions, the evaluation dimension is too singular and ignores the impact on the performance of the oil itself, and there is a lack of comprehensive consideration of the synergistic effect of soft contamination and multiple failure modes.

[0005] In view of this, the present invention provides a performance test method for high-precision turbine oil filtration. Summary of the Invention

[0006] In order to overcome the above-mentioned defects of the prior art, the present invention provides a performance test method for high-precision filtration of turbine oil to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a performance testing method for high-precision turbine oil filtration, conducted in a closed-loop oil circuit test system with precisely controllable parameters, the method comprising the following steps:

[0008] S1. Construction of the test system and preparation of the reference oil sample: Construct a closed-loop test system and prepare a reference clean turbine oil sample that meets the standard, and record its initial physicochemical properties.

[0009] S2. Simulate dynamic pollution load establishment: inject solid particulate pollutants and soluble / colloidal pollutants into the baseline clean oil sample according to a preset procedure to simulate the pollutant release characteristics in actual operation.

[0010] S3. Dynamic performance test of high-precision filter oil: The high-precision filter oil to be tested is installed in the test section and runs a multi-stage composite working condition cycle. In each stage, the number and size distribution of particles, moisture content and pressure difference of the upstream and downstream of the filter oil are collected and recorded in real time through a multi-parameter online monitoring unit.

[0011] S4. Comprehensive performance evaluation and life termination determination, continuous testing until one of the preset composite termination conditions is met;

[0012] S5. Generate a comprehensive performance report. Based on the full-process data, calculate and generate a comprehensive performance report that includes the effective dust holding capacity under dynamic operating conditions, the average filtration efficiency curve over the entire life cycle, the impact coefficient on the key physical and chemical properties of the oil, and the simulated life.

[0013] Preferably, in step S2, the establishment of the simulated dynamic pollution load specifically involves: using a program control method, co-injecting ISO-MTD standard test dust as solid particulate pollutant, and an emulsion formed by a specific formulation of oxidation degradation simulant and trace amounts of free water as soluble / colloidal pollutant. The injection process is synchronized with the low-flow-high-flow cycle of the simulated start-up and shutdown and the temperature cycle of the simulated load change.

[0014] Preferably, in step S3, the multi-stage composite operating condition cycle refers to a periodic cycle that includes at least the following four stages: constant high temperature and high flow rate stage, rapid cooling stage, low pressure fluctuation stage, and high temperature and low pressure stage. The temperature, flow rate, and pressure parameters of each stage are set and controlled by the program according to the actual operating parameter range of the target turbine oil system.

[0015] Preferably, in step S3, the data collected and recorded in real time includes at least: the number and size distribution of particles upstream and downstream of the filter oil, the moisture content upstream and downstream of the filter oil, and the real-time pressure difference between upstream and downstream of the filter oil.

[0016] Preferably, in step S4, the compound termination condition is any one of the following conditions:

[0017] The pressure difference between the upstream and downstream sides of the filter reaches 125% of the maximum value specified by the manufacturer;

[0018] The filtration ratio for key particle sizes downstream of the filter is below 90% of its nominal value for three consecutive monitoring periods;

[0019] The demulsification time or air release value of the downstream oil sample after filtration deteriorates by more than 15% compared to the initial value of the baseline clean oil sample recorded in step S1.

[0020] Preferably, step S4 further includes weighing the ash-holding capacity of the high-precision filter oil to be tested and dissecting and analyzing the filter element after the test is terminated.

[0021] Preferably, the oxidative degradation simulator is a mixed solution containing an oil-soluble metal catalyst, an organic peroxide, and a polar oxidation product.

[0022] Preferably, the cooling rate during the rapid cooling phase is not less than 5°C / min, and the pressure fluctuation amplitude during the low-pressure fluctuation phase is not less than 30% of the system's rated working pressure.

[0023] Preferably, in step S5, the influence coefficient on the key physicochemical properties of the oil is obtained by calculating the relative change rate of the demulsification time and air release value of the downstream oil sample measured during the test relative to the initial value of the benchmark clean oil sample, and then weighting and summing them.

[0024] Preferably, in the comprehensive performance report generated in step S5, the simulated life is defined as the equivalent time of cumulative operation of the multi-stage composite operating condition cycle from the start of the test to the attainment of any composite termination condition.

[0025] The technical effects and advantages of this invention are as follows:

[0026] 1. This invention not only tests the filtration efficiency and dust holding capacity of oil filters for solid particles, but also introduces the evaluation of the impact on key physical and chemical properties of oil products, and sets corresponding composite termination conditions. By calculating the influence coefficient, it can quantitatively assess whether the oil filter will lead to the deterioration of the oil product's performance during long-term operation. This method can more comprehensively identify those inferior oil filters that, although they have high filtration accuracy, may be incompatible with oil additives or may accelerate oil aging, thus providing a more reliable guarantee for the overall health of the oil system.

[0027] 2. This invention abandons the static test mode of constant temperature and constant flow and adopts a multi-stage composite working condition cycle controlled by a program. It includes stages such as rapid cooling and pressure fluctuation, and injects contaminants synchronously with these dynamic working conditions. This test environment greatly restores the real complex working state of the turbine oil system. The simulated life and performance degradation curves measured under this condition can more accurately predict the replacement cycle and performance maintenance capability of the filter in the field than the results of traditional methods, providing users with accurate and direct decision-making basis for economical maintenance and preventive maintenance.

[0028] 3. The composite termination condition set by this invention is a multi-faceted judgment system based on logical "OR", which covers three main failure paths: differential pressure blockage, efficiency reduction, and oil quality influence. It can quickly and proactively reach the performance boundary of the filter oil through a single accelerated test and identify its primary failure mode. Combined with the filter element dissection analysis after the test, it can help manufacturers and users diagnose the root cause of failure, thereby making targeted improvements to the filter oil design or optimizing system operating conditions, which has significant engineering application value. Attached Figure Description

[0029] Figure 1This is a diagram illustrating the overall method steps of the present invention. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0031] This invention provides a performance testing method for high-precision filtered turbine oil. The method is implemented in a specially designed closed-loop oil circuit testing system, which mainly includes the following components:

[0032] The oil tank is used to store turbine oil for testing. Its volume should be sufficient to meet the system circulation and have heating and cooling functions.

[0033] The main circulation pump uses frequency conversion control, which can accurately adjust the system flow and simulate the oil flow state under different loads;

[0034] The heating and cooling unit, integrated into the oil tank or main oil circuit, can programmatically control the oil temperature and achieve rapid heating and cooling.

[0035] The high-precision oil filtration test section provides a standard interface for the oil to be tested. Sampling ports and sensor interfaces are provided at both the upstream and downstream sides for easy installation and monitoring.

[0036] The online pollutant injection unit includes two independent precision injection pumps, which are used for programmed quantitative injection of solid particulate pollutant suspensions and soluble / colloidal pollutant emulsions, respectively.

[0037] The multi-parameter online monitoring unit includes:

[0038] An online particulate counter, installed upstream and downstream of the filter oil, is used to monitor and record the number and size distribution of particles in real time, in accordance with ISO11500 standard;

[0039] Online moisture sensors are installed upstream and downstream of the filter oil to monitor moisture content in real time, based on SH / T0255 standard or other equivalent principles;

[0040] Differential pressure sensor: connected across the upstream and downstream of the filter oil, used to monitor the pressure difference ΔP between the two ends of the filter oil in real time;

[0041] Temperature and pressure sensors are installed at critical points in the system;

[0042] The control system, typically an industrial computer or PLC, receives all sensor signals, controls the pumps, heating and cooling units, and contaminant injection units to operate according to preset programs, and collects, stores, and processes all test data.

[0043] The following describes the implementation process of the present invention in detail with reference to a preferred embodiment, as shown in the appendix. Figure 1 As shown:

[0044] S1. Construction of the test system and preparation of reference oil samples

[0045] In a specific embodiment, this step first involves connecting, installing, and debugging the aforementioned test system to ensure there are no leaks and that all monitoring instruments are calibrated accurately.

[0046] Select L-TSA 46 turbine oil conforming to GB 11120 standard and inject it into the oil tank. Start the main circulation pump and heating device to control the oil temperature at 50±2℃ and circulate it at this temperature for at least 4 hours to allow any trace moisture in the oil to be evenly distributed and reach equilibrium. Then, pre-clean the oil through a high-precision filtration device until the upstream online particle counter reading stabilizes at NAS0 level. At this point, take an oil sample from the system sampling port and measure its initial physicochemical indicators according to relevant national standards, including: particulate contamination degree, moisture content, demulsification time and air release value. These data are recorded as the initial value V0 of the baseline clean oil sample.

[0047] S2, Establishment of Simulated Dynamic Pollution Load

[0048] This step aims to simulate the complex contamination process of turbine oil during actual operation due to start-up, shutdown, and load changes;

[0049] Pollutant preparation:

[0050] Solid particulate pollutants: ISO12103-A3 (MTD) intermediate test dust was used. It was mixed with a small amount of reference oil sample and ultrasonically dispersed to prepare a stable suspension with a concentration of about 1.0 g / L, which was then placed in pollutant injection unit A tank.

[0051] Soluble / colloidal contaminants: Prepare an oxidation degradation simulant, which is a mixed solution containing ferric naphthenate (oil-soluble metal catalyst), tert-butyl hydrogen peroxide (organic peroxide), and polar oxidation products extracted from used turbine oil. Emulsify the simulant with a trace amount of deionized water (0.05% of the oil sample volume) under high-speed shear to form an emulsion, which is then placed in contaminant injection unit B tank.

[0052] Programmatic Cooperative Injection:

[0053] The control system initiates a dynamic pollution load setup program, which runs continuously for two simulation cycles, each lasting 60 minutes. Within each cycle:

[0054] The first 30 minutes (simulated start-up / load ramp-up phase): The system flow rate linearly increases from a low flow rate (e.g., 30% of the rated flow rate) to 100%, while the oil temperature rises from 50°C to 70°C. During this process, injection pump A injects a solid particle suspension at a constant rate to simulate system scouring and the release of wear particles, while injection pump B injects an oxidized and deteriorated simulated emulsion at a low rate.

[0055] The last 30 minutes (simulating high-load operation phase): maintain high flow rate (100%) and high temperature (70°C), pause injection pump A, and increase injection rate of injection pump B to simulate the continuous oxidation and deterioration process of oil at high temperature;

[0056] In this way, the injection of pollutants is synchronized with the simulated low-flow-high-flow and temperature cycles, which more realistically reproduces the transient characteristics of pollutant release.

[0057] S3, High-precision oil filter dynamic performance test

[0058] Using the oil sample system that has completed the above-mentioned pollution process as the test medium, a certain type of high-precision filter oil (e.g., rated precision of 3μm) to be evaluated is installed in the test section;

[0059] Initiate a multi-stage composite operating condition cyclic test program. This program defines a test cycle with a period of 120 minutes. Each cycle forces the execution of the following four stages in sequence, precisely controlled by the control system:

[0060] Constant high temperature and high flow rate stage (0-40min): Simulate the full-load stable operation of the steam turbine, control the oil temperature at (70±1)℃, the flow rate at the rated flow rate of the filter oil, and the pressure at the rated working pressure of the system. This stage mainly tests the continuous filtration capacity of the filter oil under harsh working conditions and the effect of temperature rise.

[0061] Rapid cooling phase (41-55 min): Simulates a sudden load drop or the commissioning of cooling water, controlling the oil temperature to drop rapidly from 70℃ to 45℃ at a rate of no less than 5℃ / min. During this phase, the oil viscosity increases, and the sudden temperature change may cause dissolved colloidal substances to precipitate, testing the filter oil's adaptability to changes in physical properties.

[0062] Low-pressure fluctuation stage (min 56-85): Simulate oil pump switching or system disturbance, maintain temperature at 45℃, and make the upstream pressure of the filter oil fluctuate periodically within ±20% of the rated pressure (i.e., the fluctuation amplitude is not less than 30% of the rated pressure) by adjusting the pump frequency and bypass valve. The flow rate fluctuates slightly accordingly. This stage tests the structural stability and filtration performance consistency of the filter oil under pressure shock.

[0063] High temperature and low pressure stage (86-120 min): Simulate a special working condition (such as the initial start-up), control the oil temperature to rise to 60℃, but control the system pressure at a low level (such as 50% of the rated pressure), and reduce the flow rate accordingly. This stage tests the dirt-holding characteristics of the filter oil under high temperature but weak oil flow scouring force.

[0064] Within each stage, the multi-parameter online monitoring unit automatically collects and records a set of data at fixed time intervals (e.g., every 5 minutes), including: the number of particles upstream and downstream of the filter oil (in channels such as ≥4μm, ≥6μm, ≥14μm, etc.), moisture content (ppm), and real-time pressure difference ΔP (kPa).

[0065] S4. Comprehensive Performance Evaluation and Lifespan Termination Determination

[0066] The test continues to cycle through the above combined operating conditions, and the control system determines in real time whether any of the following combined termination conditions are met:

[0067] Pressure differential condition: The real-time pressure differential ΔP between the upstream and downstream of the filter oil continuously exceeds 125% of the maximum permissible pressure differential (e.g., 200 kPa) claimed by the filter oil manufacturer (i.e., reaching 250 kPa).

[0068] Filtration efficiency condition: The calculated value of the filtration ratio β (number of upstream particles / number of downstream particles) for key particle sizes (e.g., ≥6μm) downstream of the filter oil is lower than 90% of its nominal β value (e.g., β6≥200) for three consecutive monitoring periods (3 consecutive sets of data) (i.e., β6<180).

[0069] Oil quality impact conditions: In offline analysis conducted periodically (e.g., every 8 hours of operation) from downstream samples, the demulsification time or air release value of the oil sample, compared to the baseline initial value V0 recorded in step S1, shows a degradation degree (i.e., percentage of performance loss) exceeding 15%;

[0070] Once any condition is triggered, the test will automatically stop, and the cumulative number of cycles and time will be recorded. After the test is terminated, the filter oil to be tested will be carefully removed, its ash holding capacity will be weighed, and then the filter element will be dissected to observe and record the distribution level and morphology of pollutants, as well as any abnormalities such as fiber shedding.

[0071] S5. Generate a comprehensive performance report.

[0072] Based on the monitoring and recording data from step S3 to step S4, a structured comprehensive performance report is automatically calculated and generated using the control system's built-in or external analysis software. The report must include at least the following:

[0073] Dynamic effective dust holding capacity: This value is obtained based on the final dust holding capacity weighing result. Since it is measured under dynamic working conditions, it is more valuable for reference than static dust holding capacity.

[0074] Average filtration efficiency curve over the entire life cycle: The curve is plotted with the test time on the horizontal axis and the instantaneous filtration efficiency (or β value) of particles of different sizes on the vertical axis, which intuitively shows the decay trend of oil filtration performance with test time (simulated running time).

[0075] Influence coefficient on key physicochemical properties of oil products Calculated using formulas, for example, ;

[0076] in:

[0077] This is the difference between the demulsification time of the downstream oil sample at the end of the test and the demulsification time in the baseline value V0;

[0078] This represents the demulsification time in the baseline value V0;

[0079] This is the difference between the air release value of the downstream oil sample at the end of the test and the air release value in the baseline value V0.

[0080] This represents the air release value in the reference value V0;

[0081] and Weighting coefficients set according to importance, for example =0.6, =0.4;

[0082] The smaller the value, the less negative impact the filtration has on the oil's performance;

[0083] Simulated life L: This is directly recorded as the cumulative running time of the multi-stage composite operating condition cycle from the start of the test to the triggering of the termination condition. For example, if the test is terminated after running 15 complete 120-minute cycles, then the simulated life L = 30 hours. This life is obtained under accelerated, harsh and comprehensive operating conditions and can be used to compare the durability of different filter oils.

[0084] The following tests were conducted using the method of this invention to evaluate high-precision filtered oils of equal precision made from two different materials (such as glass fiber and composite filter paper). Traditional constant pressure tests showed that the dust holding capacities of the two materials were similar. However, under the dynamic composite working condition test of this invention:

[0085] Filter A was terminated after 20 cycles because the filtration ratio β value dropped to 88% of the nominal value (trigger condition b), with a simulated life of 40 hours. A relatively high value (0.12) indicates a slight negative impact on the air release value of oil products;

[0086] Oil filter B terminated after 28 cycles due to excessive differential pressure (trigger condition a), with a simulated lifespan of 56 hours. The value is low (0.05);

[0087] The test report clearly shows that filter B has better dynamic durability and better compatibility with oil performance. Although its traditional dust holding capacity is not outstanding, this result provides a key decision-making basis that traditional methods cannot provide for power plant filter selection, fully demonstrating the beneficial effects of the method of this invention, which is comprehensive, accurate and highly predictive.

[0088] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A performance test method for high-precision turbine oil filtration, characterized in that: The method is performed in a closed-loop, parameter-accurately-controlled oil circuit test system, and comprises the following steps: S1, test system construction and reference oil sample preparation, constructing a closed-loop test system and preparing a reference clean turbine oil sample in accordance with standards, and recording the initial physical and chemical indexes thereof; S2, establishing a simulated dynamic pollution load, injecting solid particle pollutants and soluble / gelatinous pollutants into the reference clean oil sample according to a preset program to simulate the release characteristics of pollutants in actual operation; S3, high-precision oil filter dynamic performance test, installing the high-precision oil filter to be tested in the test section, and running a multi-stage composite operating condition cycle, wherein the multi-stage composite operating condition cycle refers to a periodic cycle comprising at least the following four stages: a constant high-temperature high-flow stage, a rapid cooling stage, a low-pressure fluctuation stage, and a high-temperature low-pressure stage, the temperature, flow rate and pressure parameters of each stage are set and programmed according to the actual operating parameter range of the target turbine oil system, and the particle number and size distribution, water content and pressure difference upstream and downstream of the oil filter are collected and recorded in real time by a multi-parameter online monitoring unit in each stage; S4, comprehensive performance evaluation and life termination determination, continuously testing until one of the preset composite termination conditions is reached, and the composite termination condition is any one of the following conditions: The pressure difference upstream and downstream of the oil filter reaches 125% of the maximum value specified by the manufacturer; The filtration ratio of the oil filter downstream for key particle sizes is lower than 90% of the nominal value for three consecutive monitoring periods; The demulsification time or air release value of the oil sample downstream of the oil filter is degraded by more than 15% compared to the initial value of the reference clean oil sample recorded in step S1; S5, generating a comprehensive performance report, calculating and generating a comprehensive performance report including effective dust holding capacity under dynamic operating conditions, average filtration efficiency curve in the whole life cycle, influence coefficient on key physical and chemical properties of the oil product, and simulated life based on the whole process data.

2. The method of claim 1, wherein: In step S2, the establishment of a simulated dynamic pollution load is as follows: using a program control method, ISO-MTD standard test dust is injected as a solid particle pollutant, and an emulsion formed by a specific formula of an oxidation deterioration simulation agent and a small amount of free water as a soluble / gelatinous pollutant, and the injection process is synchronized with the low-flow-high-flow cycle simulating start-stop machines and the temperature cycle simulating load changes.

3. The method of claim 1, wherein the turbine oil high efficiency filtration performance test is a turbine oil high efficiency filtration test. In step S3, the data collected and recorded in real time at least include the particle number and size distribution upstream and downstream of the oil filter, the water content upstream and downstream of the oil filter, and the real-time pressure difference between the upstream and downstream of the oil filter.

4. The method of claim 1, wherein the turbine oil high efficiency filtration performance test is a turbine oil high efficiency filtration test. Step S4 further comprises weighing the dust holding capacity of the high-precision oil filter to be tested and dissecting and analyzing the filter element after the test is terminated.

5. The method of claim 2, wherein the turbine oil high efficiency filtration performance test is a turbine oil high efficiency filtration test. The oxidation deterioration simulation agent is a mixed solution containing an oil-soluble metal catalyst, an organic peroxide and a polar oxidation product.

6. The method of claim 1, wherein the turbine oil high efficiency filtration performance test is a turbine oil high efficiency filtration test. The temperature drop rate of the rapid cooling stage is not less than 5℃ / min, and the pressure fluctuation amplitude of the low-pressure fluctuation stage is not less than 30% of the rated working pressure of the system.

7. The method of claim 1, wherein the turbine oil high efficiency filtration performance test is a turbine oil high efficiency filtration test. In step S5, the influence coefficient of the key physical and chemical properties of the oil product is obtained by calculating the relative change rate of the demulsification time and the air release value of the filtered oil downstream sample measured during the test relative to the initial value of the reference clean oil sample, and then weighting and integrating.

8. The method of claim 1, wherein the turbine oil high efficiency filtration performance test is a turbine oil high efficiency filtration performance test. In the comprehensive performance report generated in step S5, the simulation life is defined as the equivalent time of the cumulative operation of the multi-stage combined working condition cycle from the start of the test to the time when any combined termination condition is reached.

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