Method for regulating phosphonate anti-flame oil defoamer

Abstract

This invention relates to the field of power plant hydraulic operation and maintenance technology, specifically a method for regulating defoamer in phosphate ester fire-resistant oil. The method includes: selecting the defoamer to be added; determining whether to add the defoamer based on the foam condition and oil quality; when adding the defoamer, first preparing an activated mother liquor by mixing the defoamer to be added with qualified fire-resistant oil, and then adding the activated mother liquor to the fire-resistant oil at a certain oil temperature; after addition, controlling the unit's circulating pump to assist the defoamer in undergoing gradient diffusion and passivation in the oil; after passivation, replenishing the defoamer and regulating unit operation according to foam characteristics. This invention enables the appropriate selection, precise addition, and long-term maintenance of phosphate ester fire-resistant oil defoamers. By constructing a standardized technical system covering the entire process, it fills a technological gap in the industry and is applicable to foam control, oil protection, and long-term operation and maintenance of phosphate ester fire-resistant oil in high-pressure speed-regulating servo hydraulic systems of thermal power, nuclear power, and gas turbine generator sets.

Description

Technical Field

[0001] This invention relates to the field of power plant hydraulic operation and maintenance technology, specifically a method for regulating phosphate ester fire-resistant oil defoamer. Background Technology

[0002] Phosphate ester fire-resistant oil is a high-end flame-retardant hydraulic medium for power plants. It possesses characteristics such as high pressure resistance, flame retardancy, explosion prevention, and precise response. It directly undertakes core functions such as unit speed regulation, valve servo control, and system pressure stabilization. The quality and operational stability of this oil directly determine the unit's safety level. Under conditions of long-term high-pressure reciprocating motion, pump circulation and agitation, frequent load fluctuations, and slight oil aging, fire-resistant oil systems are highly prone to generating large amounts of fine suspended foam. Foam accumulation can cause system oil pressure fluctuations, servo valve jamming, delayed speed regulation response, falsely high oil levels, and poor heat dissipation. In severe cases, it can lead to unit load fluctuations and unplanned shutdowns, posing a high-frequency safety hazard for power plant operation and maintenance.

[0003] Currently, the industry commonly addresses foaming issues in fire-resistant oils by adding defoamers. For example, CN118892677B discloses a system and method for automatically adding defoamers to phosphate ester fire-resistant oil systems. The system includes a defoamer adding device, a defoamer injection device, a displacement testing device, and a defoamer adding control system. The defoamer adding control system precisely controls the injection volume, pressurization pressure, and addition process of the defoamer, ensuring effective distribution of the defoamer in the oil system while avoiding the tediousness and errors of manual operation. This invention fixes the defoamer adding device inside the fuel tank on the return oil side, ensuring that defoamer particles quickly diffuse throughout the entire fuel tank with the return oil, thus improving defoaming efficiency. Meanwhile, the bottom of the defoamer adding device is close to the oil flow position on the return side inside the oil tank, which helps to increase the concentration gradient of the defoamer and promote the uniform distribution of defoamer particles. This solves the problem that after the defoamer is added to the oil system in the form of mother liquor, the defoamer is prone to agglomeration due to its own characteristics, and then gradually floats on the top of the oil tank with the filter element replacement, and cannot form a stable and uniform dispersion system in the oil, thus failing to achieve the defoaming effect or having a poor effect.

[0004] However, existing technologies suffer from multiple systemic defects: First, there are no standards for defoamer selection, with ordinary silicone and mineral oil-based defoamers being randomly chosen on-site. These defoamers have poor compatibility with the polar phosphate ester system, easily leading to oil microemulsification and interface imbalance, resulting in a significant decrease in resistivity, an increase in acid value, and accelerated hydrolysis, severely shortening the service life of the oil. Second, the addition method is crude, generally employing direct addition of the original liquid and a high-shear diffusion mode, leading to localized enrichment of additives and severe turbulent disturbances, continuously damaging the molecular structure of fire-resistant oil, generating gum and suspended impurities, and clogging precision valve groups and filter elements. Third, there are no quantitative judgment standards for excessive foam, and the timing and amount of addition rely entirely on manual experience, easily resulting in ineffective defoaming with insufficient addition and damage to the oil with excessive addition. Fourth, there is no long-term maintenance and failure prediction mechanism, leading to passive replenishment after defoaming failure, resulting in repeated foam rebound, high maintenance frequency, and high maintenance costs. Furthermore, existing publicly available technologies mostly focus on single defoamer formulations or simple addition methods, which cannot simultaneously meet the dual requirements of efficient defoaming and zero damage to oil products, making them unsuitable for the operation and maintenance requirements of high-standard units such as nuclear power and large-scale thermal power plants. Summary of the Invention

[0005] To address the problem that existing technologies, with their single defoamer formulations or simple addition methods, cannot simultaneously meet the dual requirements of efficient defoaming and zero oil damage, this invention provides a method for regulating phosphate ester fire-resistant oil defoamers. This method is a complete set of procedures for selection, judgment, addition, stabilization, and maintenance, enabling the appropriate selection, precise addition, and long-term maintenance of phosphate ester fire-resistant oil defoamers. By constructing a standardized technical system for the entire process, it fills a technological gap in the industry and is applicable to foam control, oil protection, and long-term operation and maintenance of phosphate ester fire-resistant oil in high-pressure speed-regulating servo hydraulic systems of thermal power, nuclear power, and gas generator sets.

[0006] This invention is achieved through the following technical solution: A method for regulating phosphate ester fire-resistant oil defoamer includes: Step S1: Select the defoamer to be added according to the specific selection criteria for fire-resistant oil defoamers; Step S2: Determine whether to add defoamer based on the foaming condition and quality of the oil. Step S3: When adding defoamer, first prepare the defoamer to be added and qualified fire-resistant oil into an activated mother liquor. Then, at a certain oil temperature, add the activated mother liquor into the fire-resistant oil by uniformly dripping through a sealed replenishment port. Step S4: After addition, control the unit's circulating pump to assist the defoamer in gradient diffusion and passivation in the oil. Step S5: After passivation and shaping, add defoamer and adjust unit operation according to foam characteristics.

[0007] Preferably, in step S1, the defoamer comprises polyether-modified silicone or fluoroalkyl-modified polysiloxane. Defoamers with a bulk volume resistivity ≥1.0×10¹⁰Ω·cm at 20℃ were selected as candidate defoamers; The candidate defoamer was added to the qualified fire-resistant oil at a ratio of 0.10%. After mixing, the volume resistivity of the mixed oil sample was measured to be ≥6.0×10⁹Ω·cm (20℃), and the decrease in resistivity compared with the original liquid was ≤15%. The candidate defoamer was added to fire-resistant oil containing 0.10% water at a ratio of 0.10%. After being kept at a constant temperature of 60℃ for 72 hours, the increase in acid value was measured to be ≤0.03 mgKOH / g, and the solution remained transparent and homogeneous, without turbidity, layering, or precipitation. Under laboratory conditions, candidate defoamers were added to foamed fire-resistant oil at four gradients of 0.05%, 0.08%, 0.10%, and 0.15%, and the foam elimination time at the corresponding concentrations was measured. The defoamer with the highest defoaming efficiency and the lowest addition amount was selected as the defoamer to be added.

[0008] Preferably, in step S2, determining whether to add a defoamer and the timing of its addition based on the foaming condition and quality of the oil includes: Step S21: Measure the foam tendency index, foam stability index, and dynamic foam residence time index at two temperature ranges of 24℃ and 93.5℃ respectively. If any index exceeds the standard or is seriously exceeded, it indicates that the foam characteristics of the oil do not meet the requirements; if the foam meets the requirements, proceed to step S202. Test the resistivity, acid value, moisture content and cleanliness of the oil. If the oil is not up to standard, take corresponding treatment measures. If all the indicators of the oil are up to standard, the oil is qualified and proceed to step S202. Step S22: When both the foam and the oil are qualified, add the defoamer.

[0009] Preferably, in step S3, the defoamer to be added is prepared into an activated mother liquor by mixing the qualified fire-resistant oil with the mother liquor. Then, at a certain oil temperature, the activated mother liquor is added to the fire-resistant oil by uniform dripping through a sealed inlet. This includes: Step S31: Prepare an activation mother liquor by mixing the defoamer to be added with qualified fire-resistant oil at a mass ratio of 1:20 to 1:25. Then, stir and activate the mother liquor at room temperature until it is transparent and homogeneous, with no visible particles, no layering, and no flocculation. Then, allow it to stand and filter to obtain a clean activation mother liquor. Step S32: Close the system. Maintain static pressure or operate in steady state at ≤0.5 MPa. Add the clean activation mother liquor within 25-35 minutes at 38-42℃. The initial dosage, expressed as a percentage by mass, is determined based on the severity of excessive foaming. When the foam tendency value is 50~100mL, it is considered a slight exceedance, and the total amount added should be 0.06% of the total oil volume in the oil system. When the foam tendency value is 100~200mL, it is considered a moderate exceedance, and the total dosage should be 0.08% of the total oil volume in the oil system. When the foam tendency value is greater than 200mL and the residence time is greater than 30s, it is considered a serious overdose, and the total amount added is 0.10% of the total oil volume of the oil system.

[0010] Preferably, in step S4, during gradient diffusion, the circulation pump is turned on and controlled to operate at 30% to 40% of the rated flow rate, and the entire gradient diffusion time is 40 to 50 minutes. The gradient diffusion process includes a low flow rate stage and a medium flow rate stage. In the low flow rate stage, the circulating pump operates at 30% of the rated flow rate for 0 to 20 minutes; in the medium flow rate stage, the circulating pump operates at 30% of the rated flow rate for 20 to 50 minutes.

[0011] Preferably, in step S4, the circulation pump is stopped, and the system is left to stand in a closed environment for passivation and shaping.

[0012] Preferably, in step S5, adjusting the unit according to the foam characteristics includes: S511, determine foam characteristics, including: foam elimination time ≤20 s; foam tendency ≤50 mL at both 24℃ and 93.5℃; foam stability 0 mL; simultaneously retest resistivity and acid value to confirm that the oil has not deteriorated before addition; S512: If all the above indicators are qualified, the unit shall be restored to operation; if any indicator is unqualified, the cause shall be investigated and adjustments shall be made before the unit is put back into operation.

[0013] Preferably, in step S5, the defoamer is added according to the foam characteristics, including: Step S521: Determine the detection cycle of foam characteristics according to the unit type; Step S522: Determine whether the defoamer has entered the decay period based on the foam failure prediction threshold. When any condition of the failure threshold is met, it is determined that the defoamer has entered the decay device. Among them, the foam failure prediction thresholds include: foam tendency to rebound to >30 mL at 24℃ or 93.5℃, or foam stability at any temperature >0 mL, or dynamic foam residence time rebounding to >20 s.

[0014] Preferably, when replenishing, a graded replenishment strategy is formulated based on the foam tendency detection value. The activation mother liquor, gradient diffusion, and passivation qualitative analysis are repeatedly prepared for replenishment. After replenishment, the foam characteristics and oil quality are re-measured until the test is qualified.

[0015] The preferred strategy for staged replenishment of defoamer is as follows: The first method: When the foam tendency detection value at 24℃ or 93.5℃ is between 30mL and 50mL, it is considered a slight exceedance. A single replenishment method should be adopted, with the replenishment amount being 0.015% to 0.020% of the total oil volume of the system as activation mother liquor. The second method: When the foam tendency detection value is between 50mL and 100mL, it is considered a moderate exceedance. A single replenishment method is adopted, and the replenishment amount is 0.020% to 0.025% of the total oil volume of the system, which is the activation mother liquor. The third method is to add foam in two separate additions when the foam tendency detection value exceeds 100mL, which is considered a severe over-limit. In this case, the foam tendency detection value exceeds 100mL and is considered a severe over-limit. The foam tendency detection value is 100mL, which is 100mL, ...

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a method for regulating defoamers in phosphate ester fire-resistant oil. Through a closed-loop process of scientific selection, precise judgment, low-disturbance addition, stable formulation, and predictive maintenance, it achieves rapid defoaming, long-term foam suppression, zero oil damage, and standardized operation and maintenance. This ensures the long-term safe and stable operation of power plant hydraulic systems and resolves safety hazards such as oil pressure fluctuations, valve jamming, and abnormal unit load caused by repeated foaming. It is particularly suitable for high-precision power plant hydraulic systems. Notably, this invention pioneers a selection and adaptation mechanism, establishing a dedicated defoamer selection standard for phosphate ester fire-resistant oil. It screens specialized additives with matching polarity, insulation, and hydrolysis resistance, eliminating oil damage at the source. This solves the problems of microemulsification, resistivity reduction, and gum formation caused by chaotic traditional selection methods, thereby ensuring the long-term stability of core oil indicators.

[0017] This invention sets up a complete set of quantitative indicators, including the quantitative judgment of excessive foam, the dosage ratio, the stirring parameters, the diffusion flow rate, the settling time, and the failure prediction threshold. By defining quantifiable physical / chemical boundary conditions, it eliminates the reliance on the subjective experience of operators, thereby ensuring that the process solution has high replicability and stable treatment effect in different water quality scenarios and projects in different regions. It has the advantages of being standardized, implementable, and scalable.

[0018] This invention provides a method for regulating the defoamer of phosphate ester fire-resistant oil. The entire process is carried out at low temperature, low shear, low turbulence, and in a steady state. There are no severe disturbances in the operating conditions, and the molecular structure of the fire-resistant oil is not damaged. It can protect the natural polar head groups of the fire-resistant oil. After the addition, there is no decrease in acid value, moisture, resistivity, and cleanliness, and the oil aging rate is greatly reduced.

[0019] This invention discloses a method for regulating phosphate ester fire-resistant oil defoamer. Through mother liquor activation, gradient diffusion, and interface passivation and shaping, the defoamer molecules are stably bound throughout the process, and the defoaming speed is fast and the foam suppression cycle is long. The defoaming time can reach 4 to 8 months, which is 3 to 5 times better than the traditional method. This can reduce the workload of operation and maintenance and material costs.

[0020] The present invention provides a method for regulating the defoamer of phosphate ester fire-resistant oil, which can be completed entirely using existing equipment in the unit without any system modification. It is suitable for phosphate ester fire-resistant oil systems in various operating conditions of thermal power, nuclear power, and gas turbines, and has extremely high value for industrial application. Attached Figure Description

[0021] Figure 1 This is a flowchart of a method for regulating a phosphate ester fire-resistant oil defoamer according to the present invention. Detailed Implementation

[0022] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0023] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0024] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0025] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0026] This invention discloses a method for regulating phosphate ester fire-resistant oil defoamer, referring to... Figure 1 ,include: Step S1: Select the defoamer to be added according to the specific selection criteria for fire-resistant oil defoamers. Specifically: The components of defoamers include polyether-modified organosilicon or fluoroalkyl-modified polysiloxane. This is because both have polar groups (polyether segments / fluoroalkyl) and non-polar siloxane backbones, which can form a moderately compatible but not excessively miscible interface with the phosphate ester system. Pure mineral oil-based defoamers and pure dimethyl silicone oil (unmodified) are strictly prohibited.

[0027] Screening of defoamers for electrical insulation properties: Defoamers with a volume resistivity ≥1.0×10¹⁰Ω·cm at 20℃ were selected as candidate defoamers; The candidate defoamer was added to the qualified fire-resistant oil at a ratio of 0.10%. After mixing, the volume resistivity of the mixed oil sample was measured to be ≥6.0×10⁹Ω·cm (20℃), and the decrease in resistivity compared with the original liquid was ≤15%. Screening of defoamer hydrolysis resistance: Candidate defoamers were added to fire-resistant oil containing 0.10% water at a ratio of 0.10%. After being kept at 60℃ for 72 hours, the increase in acid value was measured to be ≤0.03 mgKOH / g, and the solution remained transparent and uniform, without turbidity, layering, or precipitation. Defoamer defoaming efficiency verification: Under laboratory conditions, candidate defoamers were added to the foamed fire-resistant oil at four gradients of 0.05%, 0.08%, 0.10%, and 0.15%, and the foam elimination time at the corresponding concentrations was measured. The defoamer with the highest defoaming efficiency and the lowest addition amount was selected as the defoamer to be added.

[0028] Step S2: Determine whether to add defoamer based on the foaming condition and quality of the oil. Specifically: The decision to add defoamer and the timing of its addition are determined based on the foaming characteristics and quality of the oil, including: Step S21: Measure the foam tendency index, foam stability index, and dynamic foam residence time index at two temperature ranges: 24℃ and 93.5℃. If any index exceeds the standard or is severely exceeded, it indicates that the foam characteristics of the oil do not meet the requirements. Take appropriate measures according to the severity until the foam characteristics of the oil meet the requirements. If the foam meets the requirements, proceed to step S202, specifically: The foam tendency index was measured at two temperatures: 24℃ and 93.5℃. The judgment criteria were the same: a foam tendency of no more than 50mL was considered acceptable; a foam tendency of more than 50mL was considered excessive, and a foam tendency of more than 200mL was considered severely excessive.

[0029] The foam stability index was also measured at two temperatures, 24℃ and 93.5℃, and the result at either temperature was taken as the standard: the foam was required to completely defoam within 10 seconds and the volume after stabilization was 0mL to be considered qualified; any residual foam visible to the naked eye (i.e., greater than 0mL) was considered to be exceeding the standard; if the volume of residual foam exceeded 10mL, it was considered to be seriously exceeding the standard.

[0030] The dynamic foam retention time index requires that it not exceed 15 seconds to be considered qualified; exceeding 15 seconds but not exceeding 30 seconds is considered exceeding the standard; exceeding 30 seconds is considered seriously exceeding the standard.

[0031] The resistivity, acid value, moisture content, and cleanliness of the oil are tested. If the oil fails to meet the standards, corresponding treatment measures are taken. If all indicators of the oil meet the standards, the oil is qualified, and step S202 is executed. Specifically: Resistivity (20℃): ≥6.0×109Ω·cm. If the value is lower than this, defoamer should not be added and regeneration treatment must be performed first. Acid value: ≤0.15 mgKOH / g. Those exceeding the standard must first undergo ion exchange regeneration to reduce the acid value. Moisture content: ≤0.10%; products exceeding this limit must first undergo vacuum filtration and dehydration. Cleanliness: ≤NAS 1638 Level 6. Those exceeding the standard must be precision filtered first.

[0032] Step S22: When both the foam and the oil are within acceptable limits, the defoamer is added. In other words, the defoamer addition process can only begin when the foam index exceeds the limit and all four oil quality indicators are within acceptable limits; if any indicator fails to meet the limit, corresponding oil quality restoration treatment must be performed until all indicators are within acceptable limits.

[0033] Step S3: When adding the defoamer, first prepare an activated mother liquor by mixing the defoamer to be added with qualified fire-resistant oil. Then, at a certain oil temperature, add the activated mother liquor to the fire-resistant oil using a sealed replenishment port and a uniform dripping method. Specifically: Step S31: Prepare an activation mother liquor by mixing the defoamer to be added with qualified fire-resistant oil at a mass ratio of 1:20 to 1:25. Then, stir and activate the mother liquor at room temperature until it is transparent and homogeneous, with no visible particles, no layering, and no flocculation. Then, allow it to stand and filter to obtain a clean activation mother liquor.

[0034] During stirring, the stirring speed is 1200-1600 r / min and the stirring time is 30-40 min; the shearing method is low-shear impeller (anchor or paddle type, linear velocity ≤3 m / s), and high-shear emulsification head should be avoided.

[0035] After stirring, seal and let stand for 10-15 minutes to allow the microbubbles entrained in the mother liquor to rise and fall naturally, while allowing the defoamer molecules to complete the initial intermolecular arrangement and interfacial orientation in the fire-resistant oil.

[0036] After standing, the activated mother liquor is filtered through a 1-3μm absolute precision filter to remove any trace amounts of insoluble matter or agglomerates, ensuring the purity of the mother liquor.

[0037] Step S32: Lock down the system (lock all servo valve adjustment actions and load adjustment operations to avoid system disturbance during addition). Maintain static pressure or steady-state operation at ≤0.5 MPa. Add clean activated mother liquor within 25-35 minutes at 38-42℃. The initial addition amount, expressed as a percentage by mass, is determined according to the severity of excessive foaming. When the foam tendency value is 50~100mL, it is considered a slight exceedance, and the total amount added should be 0.06% of the total oil volume in the oil system. When the foam tendency value is 100~200mL, it is considered a moderate exceedance, and the total dosage should be 0.08% of the total oil volume in the oil system. When the foam tendency value is greater than 200mL and the residence time is greater than 30s, it is considered a serious overdose, and the total amount added is 0.10% of the total oil volume of the oil system.

[0038] During addition, a sealed inlet should be used for uniform dripping; direct pouring from the top of the tank is strictly prohibited. System pressure, oil temperature, and oil level should be continuously monitored during addition; if any abnormality is detected, addition should be stopped immediately.

[0039] Step S4: After addition, the circulating pump of the control unit assists the defoamer in undergoing gradient diffusion and passivation in the oil. Specifically: During gradient diffusion, turn on the circulation pump and control it to run at 30% to 40% of the rated flow rate. The entire gradient diffusion process takes 40 to 50 minutes. The gradient diffusion process includes a low flow rate stage and a medium flow rate stage. In the low flow rate stage, the circulating pump runs at 30% of the rated flow rate for 0 to 20 minutes, allowing the activated mother liquor to slowly diffuse from the addition point to the periphery, avoiding excessively high local concentrations. In the medium flow rate stage, the circulating pump runs at 30% of the rated flow rate for 20 to 50 minutes, ensuring that the defoamer is homogeneously distributed throughout the system.

[0040] During the circulation diffusion process, the system pressure difference is monitored. If the pressure difference of the filter element suddenly increases beyond the warning value, it indicates that defoamer may be agglomerated and precipitated, and the process must be stopped and inspected immediately.

[0041] Stop the circulation pump and allow the system to stand in a closed environment for 1.5–2.5 hours to passivate and solidify. During this standing period, the defoamer molecules complete their directional alignment and interfacial adsorption at the oil-gas interface, forming a stable interfacial film (i.e., "passivation"). This interfacial film can effectively inhibit the formation of new foam and the merging and growth of microbubbles.

[0042] Step S5, after passivation and shaping, defoamer is added and unit operation is adjusted according to foam characteristics. Specifically: Adjusting unit operation based on foam characteristics: S511, After settling, take a sample from the system sampling port and re-determine the foam characteristics according to GB / T 12579 standard: including: foam elimination time ≤20 s; foam tendency at 24℃ and 93.5℃ ≤50 mL; foam stability 0 mL; at the same time, re-measure the resistivity and acid value to confirm that the oil has not deteriorated before addition. S512: When all the above indicators are qualified, the unit operation is restored; if any indicator is unqualified, the cause (insufficient dosage, uneven diffusion, incompatible defoamer, etc.) is investigated and adjusted before the unit is put back into operation.

[0043] The defoamer is added according to the foam characteristics, including: Step S521: Determine the detection cycle of foam characteristics according to the type of unit. For example, the foam characteristics of thermal power units operating continuously at full load are detected every 4 months, the foam characteristics of gas-fired units operating intermittently during peak shaving are detected every 6 months, and the foam characteristics of nuclear power units operating stably are detected every 8 months.

[0044] Step S522: Determine whether the defoamer has entered the decay period based on the foam failure prediction threshold. When any condition of the failure threshold is met, it is determined that the defoamer has entered the decay device. Among them, the foam failure prediction thresholds include: foam tendency to rebound to >30 mL at 24℃ or 93.5℃, or foam stability at any temperature >0 mL, or dynamic foam residence time rebounding to >20 s.

[0045] When replenishing, a graded replenishment strategy is formulated based on the foam tendency detection value. The activation mother liquor, gradient diffusion, and passivation qualitative analysis are repeatedly prepared for replenishment. After replenishment, the foam characteristics and oil quality are re-measured until the test is qualified.

[0046] The defoamer replenishment strategy is as follows: The first method: When the foam tendency detection value at 24℃ or 93.5℃ is between 30mL and 50mL, it is considered a slight exceedance. A single replenishment method should be adopted, with the replenishment amount being 0.015% to 0.020% of the total oil volume of the system as activation mother liquor. The second method: When the foam tendency detection value is between 50mL and 100mL, it is considered a moderate exceedance. A single replenishment method is adopted, and the replenishment amount is 0.020% to 0.025% of the total oil volume of the system, which is the activation mother liquor. The third method is to add foam in two separate additions when the foam tendency detection value exceeds 100mL, which is considered a severe over-limit. In this case, the foam tendency detection value exceeds 100mL and is considered a severe over-limit. The foam tendency detection value is 100mL, which is 100mL, ...

[0047] In one embodiment, a defoamer dosing log is established for each unit, recording the following information: dosing date, defoamer batch number, mother liquor ratio, dosing amount, foam characteristic data before and after dosing, complete oil quality data before and after dosing, replenishment cycle, and replenishment amount. Through long-term data accumulation, a personalized defoamer decay curve and replenishment cycle model are established for specific units.

[0048] This invention provides a method for regulating phosphate ester fire-resistant oil defoamer. Example 1 Taking a thermal power unit operating at full load continuously as an example, the specific steps for adjusting the defoamer of its corresponding phosphate ester fire-resistant oil are as follows: Step S1, Defoamer Selection: Select a polyether-modified silicone-based defoamer with a flash point of 295℃, viscosity of 550 mPa·s, and volume resistivity of 1.2 × 10¹. 0 Ω·cm, which meets the polarity adaptation requirements.

[0049] Step S2, Quantitative Judgment and Oil Quality Verification: For the fire-resistant oil system of a 300MW thermal power unit, the dynamic foam retention time was measured at 38s and the foam tendency at 65mL, indicating excessive foam levels; the oil sample resistivity was measured at 7.3×10⁻⁶. 9 The oil quality is qualified, with an Ω·cm, acid value of 0.12 mg KOH / g, and moisture content of 0.08%. The oil temperature is controlled at 40℃, the system operates under static pressure in a steady state, and the load regulation action is locked.

[0050] Step S3, preparation of mother liquor: Mix defoamer and qualified fire-resistant oil on site at a ratio of 1:22, stir at room temperature at 1400r / min with low shear for 35min, let stand for 10min, and the mother liquor is transparent and free of impurities.

[0051] Start the low-pressure auxiliary circulation, add 0.08% of the total effective dosage, and add the solution at a constant rate for 30 minutes with the liquid filling port sealed.

[0052] Step S4, gradient diffusion and passivation shaping: Circulate at low speed for 45 minutes at 35% of the rated flow rate, then let stand in a sealed environment for 2 hours; check the foam elimination time of 18 seconds, if there is no rebound and no decrease in resistivity, then restore the unit to full load operation.

[0053] Step S5, Failure Prediction and Maintenance: Test foam performance every 4 months. After reaching the decay threshold, add 0.02% activation mother liquor. The unit will operate for a long time without excessive foam or oil deterioration.

[0054] Example 2 For gas-fired intermittently operating units that utilize gas for peak shaving, the specific steps for adjusting the defoamer of the corresponding phosphate ester fire-resistant oil are as follows: Step S1, Defoamer selection: Select a low-viscosity dimethyl polysiloxane defoamer with a viscosity of 450 mPa·s, whose insulation and hydrolysis resistance properties are compatible with the phosphate ester system.

[0055] Step S2, quantitative judgment and oil quality verification: the residence time of the fire-resistant oil foam in the gas turbine unit is 35s and the foam height is 60mL, which is considered to exceed the standard; the oil quality is qualified, the precision filtration purification system is turned on for 1.5h, the oil temperature is stable at 38℃, and the system is operating under stable pressure.

[0056] Step S3, preparation of mother liquor: the defoamer and fire-resistant oil are mixed at a ratio of 1:20 and stirred at a low shear rate of 1200 r / min for 40 min to obtain a qualified activated mother liquor.

[0057] The total dosage is 0.10%, and it is added at a constant rate for 25 minutes to maintain the system in a low-pressure steady state.

[0058] Step S4, gradient diffusion and passivation shaping: circulate at 30% of the rated flow rate at low speed for 50 minutes, let stand for 1.5 hours, and the foam performance and insulation performance will all meet the standards.

[0059] Step S5, Failure Prediction and Maintenance: Perform foam performance prediction every 6 months, add 0.015% mother liquor, adapt to peak-shaving intermittent working conditions, and maintain long-term foam suppression and stability.

[0060] Example 3 Taking a nuclear power unit in stable operation as an example, the specific steps for adjusting the defoamer of its corresponding phosphate ester fire-resistant oil are as follows: Step S1, Defoamer selection: Select a high-insulation polyether modified silicone defoamer, and ensure that all compatibility indicators meet the high-standard operation and maintenance requirements of nuclear power plants.

[0061] Step S2, quantitative judgment and oil quality verification: the foam retention time of the fire-resistant oil in the nuclear power unit is 32s and the foam height is 55mL, which is considered to exceed the standard; the oil quality is qualified in all aspects, the oil temperature is stable at 42℃, and the system is locked out of all disturbance operations.

[0062] Step S3, preparation of mother liquor: the defoamer and fire-resistant oil are mixed at a ratio of 1:25 and stirred at 1600 r / min with low shear for 30 min to prepare a high-purity activated mother liquor.

[0063] Low-disturbance, precise dosing: Total dosing amount 0.06%, uniform dripping for 35 minutes, ultra-low disturbance dosing.

[0064] Step S4, gradient diffusion and passivation shaping: Circulate at 40% of the rated flow rate at low speed for 40 minutes, then let stand in a sealed environment for 2.5 hours. The interface is completely stable with no residual microbubbles.

[0065] Step S5, Failure Prediction and Maintenance: Add oil every 8 months for prediction, with an addition amount of 0.025%, ensuring zero deterioration of oil quality and zero system failures throughout the process.

[0066] Comparative Example 1 The traditional direct-injection method was adopted, without selection criteria or pre-verification. Ordinary defoamer concentrate was directly added, coupled with a high-flow-rate, high-shear diffusion system. Results showed severe foam rebound within 3-5 days after addition; after 15 days, the resistivity of the fire-resistant oil decreased to 4.2 × 10⁻⁶. 9 When the acid value increases (Ω·cm), trace amounts of suspended colloids appear in the system, the filter element pressure difference increases, and the oil performance continues to deteriorate, requiring frequent filtration and repeated addition of defoamer.

[0067] Performance comparison tests, conducted according to the DL / T 571-2014 standard, showed that the fire-resistant oil treated by the method of this invention rapidly eliminated foam without rebound, and maintained stable resistivity, acid value, moisture content, particle size, and oxidation stability throughout the process, with no emulsification, no gum, and no sedimentation. Compared with traditional methods, the effective defoaming cycle is increased by more than 4 times, and the oil aging rate is reduced by 40%. This method can solve the core problems of unstable defoaming and easy damage to oil products caused by traditional technologies, and fully meets the operation and maintenance standards of various high-end power plant units.

[0068] In summary, for phosphate ester fire-resistant oil systems, this invention provides a method for regulating defoamers in phosphate ester fire-resistant oil. Firstly, it establishes a dedicated defoamer selection standard and a complete set of quantitative control indicators to address the oil quality degradation problem caused by the chaotic selection process in traditional methods. During the addition process, a steady-state addition process with low temperature, low shear, and low turbulence is employed throughout to ensure zero oil degradation and no decline in core indicators such as acid value and resistivity. Furthermore, the defoaming time is improved through activation diffusion and interface passivation. Simultaneously, the overall regulation method relies on existing equipment without modification and can be widely adapted to various units such as thermal power, nuclear power, and gas turbines, possessing extremely high industrial application value.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the technical solution of the present invention in any way. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can be modified and replaced in several simple ways, and these modifications and replacements are all within the scope of protection covered by the claims.

Claims

1. A method for regulating the defoaming agent of phosphate ester fire-resistant oil, characterized in that, include: Step S1: Select the defoamer to be added according to the specific selection criteria for fire-resistant oil defoamers; Step S2: Determine whether to add defoamer based on the foaming condition and quality of the oil. Step S3: When adding defoamer, first prepare the defoamer to be added and qualified fire-resistant oil into an activated mother liquor. Then, at a certain oil temperature, add the activated mother liquor into the fire-resistant oil by uniformly dripping through a sealed replenishment port. Step S4: After addition, control the unit's circulating pump to assist the defoamer in gradient diffusion and passivation in the oil. Step S5: After passivation and shaping, add defoamer and adjust unit operation according to foam characteristics.

2. The method for regulating the defoamer of phosphate ester fire-resistant oil according to claim 1, characterized in that, In step S1, the defoamer comprises polyether-modified silicone or fluoroalkyl-modified polysiloxane. Defoamers with a bulk volume resistivity ≥1.0×10¹⁰Ω·cm at 20℃ were selected as candidate defoamers; The candidate defoamer was added to the qualified fire-resistant oil at a ratio of 0.10%. After mixing, the volume resistivity of the mixed oil sample was measured to be ≥6.0×10⁹Ω·cm (20℃), and the decrease in resistivity compared with the original liquid was ≤15%. The candidate defoamer was added to fire-resistant oil containing 0.10% water at a ratio of 0.10%. After being kept at a constant temperature of 60℃ for 72 hours, the increase in acid value was measured to be ≤0.03 mgKOH / g, and the solution remained transparent and homogeneous, without turbidity, layering, or precipitation. Under laboratory conditions, candidate defoamers were added to foamed fire-resistant oil at four gradients of 0.05%, 0.08%, 0.10%, and 0.15%, and the foam elimination time at the corresponding concentrations was measured. The defoamer with the highest defoaming efficiency and the lowest addition amount was selected as the defoamer to be added.

3. The method for regulating the defoamer of phosphate ester fire-resistant oil according to claim 2, characterized in that, In step S2, the decision on whether to add defoamer and the timing of its addition are determined based on the foaming condition and quality of the oil, including: Step S21: Measure the foam tendency index, foam stability index, and dynamic foam residence time index at two temperature ranges of 24℃ and 93.5℃ respectively. If any index exceeds the standard or is seriously exceeded, it indicates that the foam characteristics of the oil do not meet the requirements; if the foam meets the requirements, proceed to step S202. Test the resistivity, acid value, moisture content and cleanliness of the oil. If the oil is not up to standard, take corresponding treatment measures. If all the indicators of the oil are up to standard, the oil is qualified and proceed to step S202. Step S22: When both the foam and the oil are qualified, add the defoamer.

4. The method for regulating the defoamer of phosphate ester fire-resistant oil according to claim 1, characterized in that, In step S3, the defoamer to be added is prepared into an activated mother liquor by mixing the qualified fire-resistant oil. Then, at a certain oil temperature, the activated mother liquor is added to the fire-resistant oil at a uniform drip rate through a sealed replenishment port. This includes: Step S31: Prepare an activation mother liquor by mixing the defoamer to be added with qualified fire-resistant oil at a mass ratio of 1:20 to 1:

25. Then, stir and activate the mother liquor at room temperature until it is transparent and homogeneous, with no visible particles, no layering, and no flocculation. Then, allow it to stand and filter to obtain a clean activation mother liquor. Step S32: Close the system. Maintain static pressure or operate in steady state at ≤0.5 MPa. Add the clean activation mother liquor within 25-35 minutes at 38-42℃. The initial dosage, expressed as a percentage by mass, is determined based on the severity of excessive foaming. When the foam tendency value is 50~100mL, it is considered a slight exceedance, and the total amount added should be 0.06% of the total oil volume in the oil system. When the foam tendency value is 100~200mL, it is considered a moderate exceedance, and the total dosage should be 0.08% of the total oil volume in the oil system. When the foam tendency value is greater than 200mL and the residence time is greater than 30s, it is considered a serious overdose, and the total amount added is 0.10% of the total oil volume of the oil system.

5. The method for regulating the defoamer of phosphate ester fire-resistant oil according to claim 1, characterized in that, In step S4, during gradient diffusion, the circulation pump is turned on and controlled to run at 30% to 40% of the rated flow rate. The entire gradient diffusion takes 40 to 50 minutes. The gradient diffusion process includes a low flow rate stage and a medium flow rate stage. In the low flow rate stage, the circulating pump operates at 30% of the rated flow rate for 0 to 20 minutes. During the medium flow stage, the circulating pump operates at 30% of its rated flow for 20-50 minutes.

6. The method for regulating the defoamer of phosphate ester fire-resistant oil according to claim 1, characterized in that, In step S4, the circulation pump is stopped, and the system is sealed and left to stand for passivation and shaping.

7. The method for regulating the defoamer of phosphate ester fire-resistant oil according to claim 1, characterized in that, In step S5, the unit is adjusted according to the foam characteristics, including: S511, determine foam characteristics, including: foam elimination time ≤20 s; foam tendency ≤50 mL at both 24℃ and 93.5℃; foam stability 0 mL; simultaneously retest resistivity and acid value to confirm that the oil has not deteriorated before addition; S512: If all the above indicators are qualified, the unit shall be restored to operation; if any indicator is unqualified, the cause shall be investigated and adjustments shall be made before the unit is put back into operation.

8. The method for regulating the defoamer of phosphate ester fire-resistant oil according to claim 1, characterized in that, In step S5, defoamer is added according to the foam characteristics, including: Step S521: Determine the detection cycle of foam characteristics according to the unit type; Step S522: Determine whether the defoamer has entered the decay period based on the foam failure prediction threshold. When any condition of the failure threshold is met, it is determined that the defoamer has entered the decay device. Among them, the foam failure prediction thresholds include: foam tendency to rebound to >30 mL at 24℃ or 93.5℃, or foam stability at any temperature >0 mL, or dynamic foam residence time rebounding to >20 s.

9. The method for regulating the defoamer of phosphate ester fire-resistant oil according to claim 8, characterized in that, When replenishing, a graded replenishment strategy is formulated based on the foam tendency detection value. The activation mother liquor, gradient diffusion, and passivation qualitative analysis are repeatedly prepared for replenishment. After replenishment, the foam characteristics and oil quality are re-measured until the test is qualified.

10. The method for regulating the defoamer of phosphate ester fire-resistant oil according to claim 9, characterized in that, The defoamer replenishment strategy is as follows: The first method: When the foam tendency detection value at 24℃ or 93.5℃ is between 30mL and 50mL, it is considered a slight exceedance. A single replenishment method should be adopted, with the replenishment amount being 0.015% to 0.020% of the total oil volume of the system as activation mother liquor. The second method: When the foam tendency detection value is between 50mL and 100mL, it is considered a moderate exceedance. A single replenishment method is adopted, and the replenishment amount is 0.020% to 0.025% of the total oil volume of the system, which is the activation mother liquor. The third method is to add foam in two separate additions when the foam tendency detection value exceeds 100mL, which is considered a severe over-limit. In this case, the foam tendency detection value exceeds 100mL and is considered a severe over-limit. The foam tendency detection value is 100mL, which is 100mL, ...

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