Oil-water interface optimization control method of crude oil three-phase separator

Abstract

The invention relates to the technical field of crude oil pretreatment, in particular to an oil-water interface optimization control method of a crude oil three-phase separator, which comprises the following steps: firstly, separating crude oil according to separation parameters, and selecting different treatment modes according to the thickness of an emulsion film in the separation process; and then periodically calculating an oil-water separation offset characterization coefficient S when the separation parameters are automatically adjusted based on the PID controller, judging whether the separation has a risk or not based on the oil-water separation offset characterization coefficient S, and adaptively correcting various parameters causing the risk when the risk exists. The control method provided by the invention solves the problem that the traditional technology is insufficient in risk pre-judgment, emulsification membrane interference and parameter correction capability, and realizes comprehensive optimization of the crude oil separation process by intelligently detecting and optimizing the emulsification membrane, constructing a water separation offset characterization coefficient and timely correcting various parameters when the quality out-of-control risk is detected, so that the crude oil separation efficiency is improved. The oil-water separation efficiency and stability of crude oil are improved.

Description

Technical Field

[0001] This invention relates to the field of crude oil pretreatment technology, specifically to a method for optimizing and controlling the oil-water interface in a crude oil three-phase separator. Background Technology

[0002] In the petroleum industry, crude oil separation is a crucial step. Its core objective is to remove impurities such as water, silt, and salt from crude oil through separation operations, thereby ensuring the purity of the crude oil and improving the quality of subsequent processed products. Currently, three-phase separators are widely used for separating water, oil, and gas from crude oil. Oil-water interface control is the core element of this separation process.

[0003] However, traditional oil-water interface control technology mainly relies on manual experience to adjust the parameters of the three-phase separator and controls the oil-water interface through PID control or float-linkage mechanisms. Such control methods are typically based on fixed parameters or simple adjustments, lacking the ability to dynamically adjust multiple parameters comprehensively. Therefore, they are ill-suited to address the numerous problems that may arise from the complex components during crude oil separation. Furthermore, PID control or float-linkage mechanisms often exhibit lag, making it difficult to predict and eliminate potential fluctuation risks, thereby reducing separation efficiency and affecting the purity of crude oil and the quality of subsequent processed products. In addition, because the emulsion film blurs the oil-water interface and is constantly changing, existing methods relying on PID control or float-linkage mechanisms to adjust the oil-water interface cannot accurately sense and effectively regulate it, resulting in insufficient control accuracy and response speed.

[0004] In summary, optimizing the stability of the oil-water interface during crude oil separation, improving the stability of oil-water separation, avoiding the adverse effects of emulsion films on separation results, timely detection of potential quality degradation risks, and comprehensive adjustment of the operating parameters of the three-phase separator in response to quality degradation risks have become pressing research challenges in the current petroleum industry.

[0005] Chinese patent CN118110492A discloses an integrated separator device with three-phase separation function, comprising: a reflective deflection plate, a coalescing plate, an anti-foaming plate, an oil-water baffle, and a demister disposed within a tank; a liquid inlet disposed on the tank, with a second branch valve connected to the liquid inlet and a control valve; the oil-water baffle disposed at the bottom of the tank, with an oil vortex eliminator and a water vortex eliminator disposed at the bottom of the tank; a liquid level sensor disposed at the bottom of the anti-foaming plate; the demister connected to an outlet through the tank, with a first pressure gauge and a first pressure regulating valve disposed at the outlet; the reflective deflection plate connected to a safety valve through the tank, with a second pressure gauge and a second pressure regulating valve disposed on the safety valve. This device allows remote control of the sensors and valves within the separator via a separator control module and a communication module. While this device improves the automation level of the separator operation to some extent, it still fails to overcome the inherent defects of traditional control technologies in terms of oil-water interface control accuracy and response speed. Meanwhile, the device failed to offer effective solutions to the problems of oil-water interface blurring and dynamic changes caused by emulsion films. Furthermore, its adaptability to complex component changes during crude oil separation and its ability to predict and comprehensively correct potential quality decline remain limited, failing to fundamentally address the complex challenges of oil-water interface control in current crude oil separation processes. Therefore, further optimization and improvement of crude oil separation technology, particularly innovation in oil-water interface control, remains a crucial area requiring breakthroughs in the petroleum industry. Summary of the Invention

[0006] This invention provides an optimized control method for the oil-water interface of a crude oil three-phase separator, which overcomes the problem that traditional control technology has weak comprehensive correction capabilities when predicting fluctuation risks and emulsion film interference, resulting in unsatisfactory oil-water separation effect.

[0007] A method for optimizing the oil-water interface control of a crude oil three-phase separator includes separating crude oil based on pre-set separation parameters of the three-phase separator. The primary adjustment strategy is determined based on the emulsion film thickness, including automatically adjusting each separation parameter based on the PID controller in the three-phase separator when the emulsion film thickness is less than or equal to the set emulsion film thickness threshold, or increasing the emulsifier injection rate in the separation parameters based on the ratio of the emulsion film thickness to the emulsion film thickness threshold and continuously monitoring when the emulsion film thickness is greater than the emulsion film thickness threshold. Real-time acquisition of oil and water purity data, and periodic calculation of the oil-water separation offset characterization coefficient S based on the average oil purity and average water purity within the current period. , in, , This is the oil output weighting coefficient. This is the effluent weighting coefficient. This represents the average oil purity during this cycle. This represents the average purity of the effluent during this cycle. Minimum oil purity Minimum effluent purity; Based on the oil-water separation offset characterization coefficient S, determine whether there is a risk in the separation, and when a risk is determined to exist, correct each of the separation parameters, the primary adjustment strategy selection parameters, and the PID controller control parameters, and issue a notification.

[0008] Furthermore, the process of determining whether there is a risk in the separation based on the oil-water separation offset characterization coefficient S includes: The oil-water separation offset characterization coefficient S is calculated based on the average oil purity and the average water purity within this cycle. If the oil-water separation offset characterization coefficient S is less than or equal to the preset oil-water separation offset characterization coefficient, it is determined that there is a risk in the separation, and the opening of the oil inlet valve in the separation parameters is corrected based on the ratio of the preset oil-water separation offset characterization coefficient to the oil-water separation offset characterization coefficient S. If the oil-water separation offset characterization coefficient S is greater than the preset oil-water separation offset characterization coefficient, it is determined that there is no risk in the separation, the parameters are maintained and the detection continues; Wherein, the oil purity refers to the proportion of the mass of the oil component in the total mass of the oil sample obtained from the three-phase separator, and the water purity refers to the proportion of the mass of the water component in the total mass of the water sample obtained from the three-phase separator.

[0009] Furthermore, the process of correcting the inlet valve opening in the separation parameters based on the ratio of the preset oil-water separation offset characterization coefficient to the oil-water separation offset characterization coefficient S includes: The separation offset ratio is determined based on the ratio of the preset oil-water separation offset characterization coefficient to the oil-water separation offset characterization coefficient S. The opening degree of the oil inlet valve is reduced based on the separation offset ratio, and the reduction in the opening degree of the oil inlet valve is proportional to the separation offset ratio.

[0010] Furthermore, the process of correcting the target temperature value of the temperature controller in the separation parameters based on the difference in the opening degree of the inlet valve before and after correction includes: The inlet valve difference is determined based on the difference in the opening degree of the inlet valve before and after the correction, and the target temperature value of the temperature controller is increased based on the inlet valve difference, and the increase in the target temperature value of the temperature controller is proportional to the inlet valve difference.

[0011] Furthermore, based on the corrected oil-water separation offset characterization coefficient S, the process of determining whether there is a risk in the separation includes: The risk of separation is determined based on the corrected oil-water separation offset characterization coefficient S. If the corrected oil-water separation offset characterization coefficient S is less than or equal to the preset oil-water separation offset characterization coefficient, it is determined that there is a risk in the separation, and the emulsion film thickness threshold is corrected based on the ratio of the average oil outlet density in this cycle to the preset average oil outlet density. If the corrected oil-water separation offset characterization coefficient S is greater than the preset oil-water separation offset characterization coefficient, it is determined that there is no risk in the separation, the parameters are maintained and the detection continues; The emulsion film thickness threshold refers to the maximum thickness of the emulsion film at the oil-water interface inside the three-phase separator when the PID controller in the three-phase separator automatically adjusts the separation parameters. The average oil outlet density refers to the average density of the oil sample separated from the three-phase separator in the current cycle.

[0012] Furthermore, the process of correcting the emulsion film thickness threshold based on the ratio of the average oil outlet density to the preset average oil outlet density during this period includes: The oil outlet density ratio is determined based on the ratio of the average oil outlet density during this period to the preset average oil outlet density, and the emulsion film thickness threshold is reduced based on the oil outlet density ratio, with the reduction in the emulsion film thickness threshold being proportional to the oil outlet density ratio.

[0013] Furthermore, based on the revised oil-water separation offset characterization coefficient S, the process of determining whether there is a risk in the separation includes: The risk of separation is determined based on the revised oil-water separation offset characterization coefficient S. If the revised oil-water separation offset characterization coefficient S is less than or equal to the preset oil-water separation offset characterization coefficient, it is determined that there is a risk of separation, and the PID controller proportional band is corrected based on the number of times the PID controller output control signal is corrected for each component within this cycle. If the revised oil-water separation offset characterization coefficient S is greater than the preset oil-water separation offset characterization coefficient, it is determined that there is no risk in the separation, the parameters are maintained, and the detection continues.

[0014] Furthermore, the process of correcting the proportional band of the PID controller based on the number of times the PID controller outputs control signals to correct each component within this cycle includes: The PID automatic correction frequency is determined based on the number of times the PID controller outputs control signals to correct each component within this cycle. The proportional band is increased based on the PID automatic correction frequency, and the increase in the proportional band is proportional to the PID automatic correction frequency.

[0015] Furthermore, based on the revised oil-water separation offset characterization coefficient S, the process of determining whether there is a risk in the separation includes: Based on the revised oil-water separation offset characterization coefficient S, determine whether there is a risk in the separation process; If the oil-water separation offset characterization coefficient S after another correction is less than or equal to the preset oil-water separation offset characterization coefficient, then it is determined that the measurement signal is drifting, there is a risk of separation, and a measurement signal drift warning is output. In addition, the integral time in the PID controller is increased based on the ratio of the interface height standard deviation to the preset interface height standard deviation. If the revised oil-water separation offset characterization coefficient S is greater than the preset oil-water separation offset characterization coefficient, it is determined that there is no risk to the separation, the parameters are maintained and the detection continues. The standard deviation of the interface height refers to the standard deviation of the height of the oil-water interface within the current period.

[0016] Furthermore, the process of increasing the integral time in the PID controller based on the ratio of the interface height standard deviation to the preset interface height standard deviation includes: The interface height standard deviation ratio is determined based on the ratio of the interface height standard deviation to the preset interface height standard deviation, and the integration time is increased based on the interface height standard deviation ratio, wherein the increase in integration time is proportional to the interface height standard deviation ratio.

[0017] Compared with existing technologies, the advantages of this invention lie in its innovative oil-water interface optimization control method for crude oil three-phase separators. This invention effectively addresses the shortcomings of traditional control technologies in predicting fluctuation risks, overcoming emulsion film interference, and automatically correcting parameters. First, by monitoring the emulsion film thickness and combining it with the automatic adjustment function of the PID controller, the separation parameters are dynamically optimized, enabling precise response to interference from the emulsion film. Second, the introduction of the oil-water separation offset characterization coefficient S allows for a quantitative evaluation of the separation effect, enabling the invention to predict the risk of quality degradation during the separation process. Furthermore, once a risk is detected, the invention automatically corrects the separation parameters, adjusts the primary strategy selection parameters, and optimizes the control parameters of the PID controller, thereby achieving comprehensive optimization of the separation process. This dynamic adjustment mechanism not only improves the system's adaptability but also significantly enhances the oil-water separation effect, ensuring the efficiency and stability of the separation process.

[0018] Furthermore, by comparing the S-value with a preset value, the deviation of the separation effect is precisely quantified, thereby determining whether a risk exists. When the S-value is lower than the preset value, the inlet valve opening is adjusted using the ratio of the preset value to S, dynamically adjusting the separation load. This method not only improves the accuracy of risk assessment but also achieves precise control through quantified ratios, avoiding the lag and crudeness of traditional control methods, and enhancing the stability and reliability of the separation process.

[0019] Furthermore, by dynamically adjusting the valve opening based on the separation offset ratio, a precise response to separation risks is achieved. This method is based on the direct proportionality between the separation offset ratio and the valve opening adjustment range, which allows for reasonable adjustment of the valve opening according to the level of risk while avoiding the impact of over-adjustment on the system. This dynamic adjustment strategy not only improves the system's response speed and adaptability but also enhances the stability of the separation process, ensuring optimized separation results.

[0020] Furthermore, adjusting the inlet valve opening may cause changes in the emulsion film thickness, thus affecting the separation effect. By adjusting the temperature based on the inlet valve differential, the coalescence and sedimentation of oil and water droplets are promoted, optimizing the separation effect. This method achieves coordinated optimization among separation parameters, improves the system's energy efficiency and economy, enhances its adaptability to complex operating conditions, and further improves the stability of the separation process.

[0021] Furthermore, after initial parameter correction, the presence of separation risk is assessed again based on the corrected oil-water separation offset characterization coefficient S. This further confirms whether the separation process has truly stabilized, avoiding misjudgments due to the limitations of a single correction measure. On this basis, when the risk still exists, the emulsion film thickness threshold is adaptively adjusted to ensure it remains optimal. This effectively addresses complex operating conditions caused by changes in crude oil properties and enhances the system's adaptability to dynamic changes in the emulsion film.

[0022] Furthermore, by dynamically adjusting the emulsion film thickness threshold, the system can accurately address separation risks based on changes in crude oil properties. This adjustment method, based on the direct proportionality between the oil outlet density ratio and the adjustment range of the emulsion film thickness threshold, achieves adaptive control of the emulsion film thickness, improves the system's adaptability, further optimizes the control precision of the separation process, and ensures efficient oil-water separation.

[0023] Furthermore, when the separation effect still does not improve, the PID controller's calibration frequency is analyzed to determine if the PID controller is overly sensitive. Based on the calibration frequency, the proportional band is dynamically adjusted to reduce the controller's over-response and minimize oscillations. This method achieves dynamic optimization of the PID controller parameters, enhances system stability, and further improves the system's robustness and the reliability of the separation effect.

[0024] Furthermore, by analyzing the calibration frequency of the PID controller and dynamically optimizing the proportional band parameters, oscillations caused by an excessively narrow proportional band in the PID controller are avoided, while ensuring the system's rapid response to the separation process. This dynamic optimization strategy improves the system's adaptability to complex operating conditions, enhances the stability of the separation process, further optimizes the control effect, and ensures the efficient operation of the separation process.

[0025] Furthermore, if the separation effect remains unimproved after ruling out all possibilities such as process load, separation temperature, emulsion layer state, and controller parameter misalignment, the root cause can be diagnosed as signal drift in the sensor measuring the oil-water interface. At this point, the system issues a warning to notify manual instrument maintenance. Simultaneously, it dynamically adjusts the integral time based on the interface height standard deviation ratio. This correction method not only accurately detects and promptly notifies when anomalies that are difficult to repair are identified, but also optimizes the PID controller's adaptability to signal drift, avoiding extreme actuator actions caused by integral saturation, thus improving the system's robustness and safety.

[0026] Furthermore, by dynamically adjusting the integral time of the PID controller based on the ratio of the interface height standard deviation, the system can adaptively reduce the controller's integral action according to the severity of the fault. When the signal is slightly abnormal, the integral action is only moderately reduced to maintain control accuracy; while when the signal is severely unreliable, the integral action is significantly suppressed, causing the control system to switch from a precise tracking mode to a fault-tolerant mode focused on stability. This design achieves a precise match between the severity of the fault and the extent of control strategy degradation, not only improving the system's robustness and safety under abnormal sensor conditions but also providing a quantitative basis for manual intervention, demonstrating a shift from passive alarm to proactive adaptive protection. Attached Figure Description

[0027] Figure 1 This is a flowchart illustrating the oil-water interface optimization control method for a crude oil three-phase separator in this embodiment of the invention. Figure 2 This is a flowchart illustrating the process of determining the presence of risk in oil-water separation based on the oil-water separation offset characterization coefficient S in an embodiment of the present invention. Figure 3 This is a flowchart illustrating the correction of the inlet valve opening based on the separation offset ratio in an embodiment of the present invention; Figure 4 This is a flowchart illustrating the process of correcting the target temperature value of the temperature controller based on the inlet valve difference in an embodiment of the present invention. Detailed Implementation

[0028] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0029] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0030] This invention provides a method for optimizing and controlling the oil-water interface in a crude oil three-phase separator, comprising: Crude oil is separated based on pre-set separation parameters of the three-phase separator; The primary adjustment strategy is determined based on the emulsion film thickness, including automatically adjusting each separation parameter based on the PID controller in the three-phase separator when the emulsion film thickness is less than or equal to the set emulsion film thickness threshold, or increasing the emulsifier injection rate in the separation parameters based on the ratio of the emulsion film thickness to the emulsion film thickness threshold and continuously monitoring when the emulsion film thickness is greater than the emulsion film thickness threshold. Real-time acquisition of oil and water purity data, and periodic calculation of the oil-water separation offset characterization coefficient S based on the average oil purity and average water purity within the current period. ; in, , This is the oil output weighting coefficient. This is the effluent weighting coefficient. This represents the average oil purity during this cycle. This represents the average purity of the effluent during this cycle. Minimum oil purity Minimum effluent purity; Based on the oil-water separation offset characterization coefficient S, determine whether there is a risk in the separation, and when a risk is determined to exist, correct each of the separation parameters, the primary adjustment strategy selection parameters, and the PID controller control parameters, and issue a notification.

[0031] The thickness of the emulsion film can be obtained through a capacitor array; The separation parameters include, but are not limited to, oil pump flow rate, oil inlet valve opening, separator internal operating pressure, oil inlet pressure, oil outlet pressure, temperature controller target temperature value, oil-water interface height, emulsifier injection rate, oil-water interface height, oil outlet flow rate, water outlet flow rate, PID controller integral time, PID controller proportional coefficient, PID controller derivative gain, and gas phase regulating valve opening, etc., which will not be elaborated here. The value range of the oil inlet valve opening degree SOR is 30%-80% to adapt to changes in crude oil flow rate under different requirements; The emulsion film thickness threshold EFT1 refers to the maximum thickness of the emulsion film at the oil-water interface inside the three-phase separator when the PID controller in the three-phase separator automatically adjusts the separation parameters. The impact of the emulsion film varies with different types of crude oil, but it is generally believed that when the emulsion film thickness exceeds 80 mm, the water content in the oil phase will increase by 3-5 times. Therefore, the range of the emulsion film thickness threshold EFT1 is set to 30 mm-70 mm. Specifically, the process of determining the primary adjustment strategy based on the emulsion film thickness includes: The emulsion film thickness EFT is obtained and compared with the preset emulsion film thickness threshold EFT1; If the emulsion film thickness EFT is less than or equal to the emulsion film thickness threshold EFT1, then the separation parameters are automatically adjusted based on the PID controller in the three-phase separator. If the emulsion film thickness EFT is greater than the emulsion film thickness threshold EFT1, then the emulsifier injection rate in the separation parameters is increased based on the ratio of the emulsion film thickness to the emulsion film thickness threshold, and this is continuously monitored. Specifically, the process of increasing the emulsifier injection rate in the separation parameters based on the ratio of emulsion film thickness to emulsion film thickness threshold includes: The film thickness ratio (FTR) is determined based on the ratio of the emulsion film thickness to the emulsion film thickness threshold. The film thickness ratio FTR is compared with the set first preset film thickness ratio FTR1 and second preset film thickness ratio FTR2. When the emulsion film thickness reaches 100mm, it may not only cause a sharp increase in the water content in the oil sample, but also cause the valve controlled by the PID controller to operate frequently. Therefore, the first preset film thickness ratio is set... The second preset film thickness ratio ; If the film thickness ratio FTR is less than or equal to the film thickness ratio FTR1, then the first emulsifier correction threshold is used. The modified emulsifier injection rate ED, the modified emulsifier injection rate Among them, a first emulsifier correction threshold is set. ; If the film thickness ratio FTR is less than or equal to the film thickness ratio FTR1, then a second emulsifier is used to correct the threshold. The modified emulsifier injection rate ED, the modified emulsifier injection rate Among them, a second emulsifier correction threshold is set. ; If the film thickness ratio FTR is less than or equal to the film thickness ratio FTR1, then a third emulsifier is used to correct the threshold. The modified emulsifier injection rate ED, the modified emulsifier injection rate Among them, a third emulsifier correction threshold is set. .

[0032] The oil purity refers to the proportion of the oil component mass in the total mass of the oil sample separated from the three-phase separator. Currently, when separating crude oil using a three-phase separator, a qualified oil purity is generally considered to be greater than or equal to 99.5%. To achieve early warning, the oil purity is set to 99.3%. The water purity refers to the proportion of the water component mass in the total mass of the water sample separated from the three-phase separator. Currently, a water content in the oil sample is generally considered to be greater than or equal to 99.8%, and the water purity is set to 99.6%.

[0033] Specifically, the oil-water separation offset characterization coefficient , in, , This is the oil output weighting coefficient. This is the effluent weighting coefficient. This represents the average oil purity during this cycle. This represents the average purity of the effluent during this cycle. Minimum oil purity Minimum effluent purity; The primary objective of a three-phase separator is to effectively separate oil, water, and gas from crude oil, ensuring that the water content in the effluent and the oil content in the effluent meet process requirements. Therefore, the purity of the effluent directly reflects the effectiveness of the separation and is a core indicator. To avoid the influence of instantaneous fluctuations, measurement errors, or interference, this invention uses the average oil purity and the average water purity within the current cycle to calculate the oil-water separation offset characterization coefficient S. In the oil-water separation offset characterization coefficient S... and The impurities of the current oil and water output were measured separately, and then compared with... After comparison, it will reflect the degree of deviation of the separated oil and water samples from the ideal state. Subsequently, in order to combine the two parameters with different units and ranges, the deviation of the actual oil and water samples from the ideal state is normalized. For crude oil separation, although both water purity and oil purity are important parameters for judging the water-oil separation effect, oil purity often has more stringent requirements. Therefore, different weights are assigned to the deviation of the oil and water samples from the ideal state. In general, the oil-water separation deviation characterization coefficient S essentially quantifies the degree of deviation of the separation effect from the minimum allowable purity. Therefore, compared with the traditional three-phase separator separation control relying on single-parameter threshold triggering, the oil-water separation deviation characterization coefficient S can detect the risk of oil-water separation decline in advance, thereby achieving rapid early warning and timely intervention, thus effectively improving the stability of oil-water separation.

[0034] Please see Figure 1 As shown, this is a flowchart of the oil-water interface optimization control method for a crude oil three-phase separator in an embodiment of the present invention. The workflow of the oil-water interface optimization control method for a crude oil three-phase separator in an embodiment of the present invention includes: S1: Separate crude oil based on pre-set separation parameters of the three-phase separator; S2: Determine a primary adjustment strategy based on the emulsion film thickness, including automatically adjusting each separation parameter based on the PID controller in the three-phase separator when the emulsion film thickness is less than or equal to the set emulsion film thickness threshold, or increasing the emulsifier injection rate in the separation parameters based on the ratio of the emulsion film thickness to the emulsion film thickness threshold and continuously monitoring when the emulsion film thickness is greater than the emulsion film thickness threshold. S3: Real-time acquisition of oil purity and water purity, and periodic calculation of oil-water separation offset characterization coefficient S based on the average value of oil purity and water purity within the current period. S4: Based on the oil-water separation offset characterization coefficient S, determine whether there is a risk in the separation, and when a risk is determined to exist, correct each of the separation parameters, the primary adjustment strategy selection parameters, and the PID controller control parameters, and issue a notification.

[0035] Furthermore, the process of determining whether there is a risk in the separation based on the oil-water separation offset characterization coefficient S includes: The oil-water separation offset characterization coefficient S is calculated based on the average oil purity and the average water purity within this cycle. If the oil-water separation offset characterization coefficient S is less than or equal to the preset oil-water separation offset characterization coefficient, it is determined that there is a risk in the separation, and the opening of the oil inlet valve in the separation parameters is corrected based on the ratio of the preset oil-water separation offset characterization coefficient to the oil-water separation offset characterization coefficient S. If the oil-water separation offset characterization coefficient S is greater than the preset oil-water separation offset characterization coefficient, it is determined that there is no risk in the separation, the parameters are maintained and the detection continues; The oil-water separation deviation coefficient S quantifies the degree of deviation of the separation effect from the minimum allowable purity. When the S value is lower than the preset threshold, it indicates that the overall score of the current separation effect has entered the warning range. Even if the purity of a single item may not have fallen below the minimum standard, the overall system has shown a trend of developing in an unfavorable direction, thus being judged as "risk exists". This design upgrades the binary judgment of "whether it exceeds the standard" to a continuous quantitative assessment of "how far is it from the safety boundary". This design realizes the transformation from passive remediation to active prevention, thereby simplifying the monitoring complexity and greatly improving the foresight and stability of the three-phase separator for oil-water interface control.

[0036] Please see Figure 2 As shown, this is a flowchart illustrating the process of determining whether there is a risk in the separation based on the oil-water separation offset characterization coefficient S in an embodiment of the present invention. The process of determining whether there is a risk in the separation based on the oil-water separation offset characterization coefficient S in this embodiment of the present invention includes: The oil-water separation offset characterization coefficient S is calculated based on the average oil purity and the average water purity within this cycle. The oil-water separation offset characterization coefficient S is compared with the preset oil-water separation offset characterization coefficient S1. For a three-phase separator, if the oil purity is higher than 99.5% and the water purity is higher than 99.8%, it is considered to meet the separation requirements. Therefore, the preset oil-water separation offset characterization coefficient S1 is set to [0.35, 0.5]. If the oil-water separation offset characterization coefficient S is less than or equal to the preset oil-water separation offset characterization coefficient S1, then it is determined that there is a risk in the separation, and the opening degree of the oil inlet valve in the separation parameters is corrected based on the ratio of the preset oil-water separation offset characterization coefficient to the oil-water separation offset characterization coefficient S. If the oil-water separation offset characterization coefficient S is greater than the preset oil-water separation offset characterization coefficient S1, it is determined that there is no risk in the separation, the parameters are maintained and the detection continues. Furthermore, the process of correcting the inlet valve opening in the separation parameters based on the ratio of the preset oil-water separation offset characterization coefficient to the oil-water separation offset characterization coefficient S includes: The separation offset ratio is determined based on the ratio of the preset oil-water separation offset characterization coefficient to the oil-water separation offset characterization coefficient S. The opening degree of the oil inlet valve is reduced based on the separation offset ratio, and the reduction in the opening degree of the oil inlet valve is proportional to the separation offset ratio.

[0037] Valves are the core actuators for regulating the load handled by the separator. When the oil-water separation offset coefficient S indicates a risk, the primary task is to reduce the feed load to restore the stability of the separation environment. Reducing the valve opening directly reduces the flow rate and prolongs the residence time of the mixture, thereby improving the separation effect from the source. The separation offset ratio precisely quantifies the severity of the risk. The larger the ratio, the further the operating condition deviates from the safety baseline. Based on this ratio, the valve opening is reduced proportionally, achieving a precise match between the control amplitude and the risk level: when the risk is small, only fine adjustments are needed to avoid production fluctuations; when the risk is large, significant adjustments are needed to quickly curb the deterioration. This constitutes a smooth, adaptive proportional control closed loop. By quantifying the risk and implementing precise on-demand control, the crude drawbacks of traditional on / off control are avoided, significantly improving the stability of the system response, control efficiency, and overall adaptability.

[0038] Please see Figure 3 The diagram shows a flowchart illustrating the process of correcting the inlet valve opening based on the separation offset ratio in an embodiment of the present invention. The process of correcting the inlet valve opening in the separation parameters based on the separation offset ratio in this embodiment includes: The separation offset ratio SOR is determined based on the ratio of the preset oil-water separation offset characterization coefficient S1 to the oil-water separation offset characterization coefficient S. The separation offset ratio SOR is compared with the set first preset separation offset ratio SOR1 and second preset separation offset ratio SOR2, ​​wherein the first preset separation offset ratio is... The second preset separation offset ratio ; If the separation offset ratio SOR is less than or equal to the first preset separation offset ratio SOR1, then the first inlet valve correction threshold is used. Correct the inlet valve opening SOR, the corrected inlet valve opening Among them, the first inlet valve correction threshold is set. ; If the separation offset ratio SOR is greater than the first preset separation offset ratio SOR1 and less than or equal to the second preset separation offset ratio SOR2, ​​then the oil inlet valve opening SOR is corrected using the second inlet valve correction threshold α2. The corrected oil inlet valve opening SOR' = SOR × α2, where the second inlet valve correction threshold α2 is set to 0.93. If the separation offset ratio SOR is greater than the second preset separation offset ratio SOR2, ​​the oil inlet valve opening SOR is corrected using the third inlet valve correction threshold α3. The corrected oil inlet valve opening SOR' = SOR × α3, where the third inlet valve correction threshold α3 is set to 0.88.

[0039] Furthermore, the process of correcting the target temperature value of the temperature controller in the separation parameters based on the difference in the opening degree of the inlet valve before and after correction includes: The inlet valve difference is determined based on the difference in the opening degree of the inlet valve before and after the correction, and the target temperature value of the temperature controller is increased based on the inlet valve difference, and the increase in the target temperature value of the temperature controller is proportional to the inlet valve difference.

[0040] Reducing the valve opening directly lowers the processing load and prolongs the residence time, which may lead to an increase in the thickness of the emulsion film. Therefore, by appropriately increasing the temperature to promote the coalescence and sedimentation of oil and water droplets, the separation effect is enhanced at a lower flow rate. The inlet valve difference reflects the intensity of the load adjustment taken by the system to cope with risks. The larger the difference, the more serious the deviation from the initial operating conditions. Based on this difference, the target temperature is increased proportionally, achieving a precise match between the temperature control compensation and the load adjustment range: when the load decreases slightly, only a slight increase in temperature is needed to avoid a sharp increase in energy consumption; when the load decreases significantly, it may indicate an increased risk of increased emulsion film thickness, so sufficient temperature increase is required to minimize the decline in separation quality. This design method achieves systematic optimization of control actions through parameter linkage, avoiding the limitations that may be caused by single parameter adjustment, and ensuring an economic balance between energy input and process requirements through proportional relationships, thereby improving overall energy efficiency while stabilizing operating conditions.

[0041] Please see Figure 4 As shown, this is a flowchart illustrating the process of correcting the target temperature value of the temperature controller based on the inlet valve difference in an embodiment of the present invention. The process of correcting the target temperature value of the temperature controller in the separation parameters based on the difference in the opening degree of the inlet valve before and after correction in this embodiment of the present invention includes: The inlet valve difference value SORD is determined based on the difference in the inlet valve opening before and after the correction. The inlet valve difference SORD is compared with the first preset inlet valve difference SORD1 and the second preset inlet valve difference SORD2, wherein the first preset inlet valve difference SORD1 is set to [0.9, 3] and the second preset inlet valve difference SORD2 is set to (3, 5]. If the inlet valve difference SORD is less than or equal to the first preset inlet valve difference SORD1, then the target temperature value TT of the temperature controller is corrected using the first temperature correction threshold β1. The corrected target temperature value TT' of the temperature controller is TT' = TT × β1, where the first temperature correction threshold β1 is set to 1.03. If the inlet valve difference SORD is greater than the first preset inlet valve difference SORD1 and less than or equal to the second preset inlet valve difference SORD2, then the target temperature value TT of the temperature controller is corrected using the second temperature correction threshold β2. The corrected target temperature value TT' of the temperature controller is TT' = TT × β2, where the second temperature correction threshold β2 is set to 1.07. If the inlet valve difference SORD is greater than the second preset inlet valve difference SORD2, then the target temperature value TT of the temperature controller is corrected using the third temperature correction threshold β1. The corrected target temperature value TT' = TT × β3, where the third temperature correction threshold β3 is set to 1.12.

[0042] Furthermore, based on the corrected oil-water separation offset characterization coefficient S, the process of determining whether there is a risk in the separation includes: The risk of separation is determined based on the corrected oil-water separation offset characterization coefficient S. If the corrected oil-water separation offset characterization coefficient S is less than or equal to the preset oil-water separation offset characterization coefficient, it is determined that there is a risk in the separation, and the emulsion film thickness threshold is corrected based on the ratio of the average oil outlet density in this cycle to the preset average oil outlet density. If the corrected oil-water separation offset characterization coefficient S is greater than the preset oil-water separation offset characterization coefficient, it is determined that there is no risk in the separation, the parameters are maintained and the detection continues; The average density of the oil outlet refers to the average density of the oil sample separated from the three-phase separator during the current cycle.

[0043] When the oil-water separation offset characterization coefficient S still indicates risk after initial physical adjustments, the current anomaly is first suspected to be caused by the deterioration of crude oil properties (such as an increase in the content of asphaltenes, gums, or solid particles in the crude oil leading to abnormal stability of the emulsion film), resulting in an unreasonable setting of the emulsion film thickness threshold. This causes the emulsion film in the three-phase separator to affect the final oil-water separation. Therefore, this invention attempts to make an adaptive correction to the emulsion film thickness threshold. This design realizes refined and intelligent fault handling. It not only avoids the invalid repetitive operation of the system when the initial measures are ineffective, but also actively optimizes the decision-making logic by evaluating the effect of its own actions, thereby greatly improving the robustness and effectiveness in dealing with complex and deep process faults.

[0044] Specifically, the process of determining whether there is a risk in the separation based on the corrected oil-water separation offset characterization coefficient S includes: The corrected oil-water separation offset characterization coefficient S' is compared with the preset oil-water separation offset characterization coefficient S1; If the corrected oil-water separation offset characterization coefficient S' is less than or equal to the preset oil-water separation offset characterization coefficient S1, then it is determined that there is a risk in the separation, and the emulsion film thickness threshold is corrected based on the ratio of the average oil outlet density in this cycle to the preset average oil outlet density. If the corrected oil-water separation offset characterization coefficient S' is greater than the preset oil-water separation offset characterization coefficient S1, it is determined that there is no risk in the separation, the parameters are maintained, and the detection continues.

[0045] Furthermore, the process of correcting the emulsion film thickness threshold based on the ratio of the average oil outlet density to the preset average oil outlet density during this period includes: The oil outlet density ratio is determined based on the ratio of the average oil outlet density during this period to the preset average oil outlet density, and the emulsion film thickness threshold is reduced based on the oil outlet density ratio, with the reduction in the emulsion film thickness threshold being proportional to the oil outlet density ratio.

[0046] The oil outlet density ratio directly quantifies the degree of deterioration in separation performance. After initial physical adjustments prove ineffective, the system determines that the root cause may lie in the deterioration of feed properties leading to the failure of the emulsion film thickness threshold. At this point, by lowering the emulsion film thickness threshold, the system proactively lowers the threshold for initiating the chemical demulsification strategy, shifting the control focus from adjustment to the more fundamental injection of emulsifier. Crucially, the threshold reduction is proportional to this ratio, ensuring the precision and economy of control actions: the more severe the deterioration in separation performance, the greater the threshold reduction, and the lower the system's "tolerance" for emulsification, thus enabling the more decisive use of chemical demulsification as the ultimate solution. Conversely, if the problem is minor, only minor adjustments are made to avoid overreaction. This design, by dynamically adjusting its decision-making benchmark based on the final product quality feedback, enables the invention to achieve adaptive optimization, thereby effectively improving the stability of oil-water separation.

[0047] Specifically, the process of correcting the emulsion film thickness threshold based on the ratio of the average oil outlet density during the current period to the preset average oil outlet density includes: The oil export density ratio (ODR) is determined based on the ratio of the average oil export density during the current period to the preset average oil export density. The range of values ​​for the preset average oil export density is determined by the type of crude oil and is not limited here. For example: The preset average density of light crude oil at the oil outlet ranges from 0.80 to 0.87 g / cm³. The preset average density of medium-quality crude oil at the oil export site ranges from 0.87 to 0.92 g / cm³. The preset average density of heavy crude oil at the oil outlet ranges from 0.92 to 1.00 g / cm³. The preset average density of extra-heavy oil / asphalt oil at the outlet ranges from 1.00 g / cm³. The oil outlet density ratio ODR is compared with the first preset oil outlet density ratio ODR1 and the second preset oil outlet density ratio ODR2. When the water content in the oil sample is less than 0.05%, it has almost no effect on the density of the oil sample. However, when the water content reaches 0.5%, the crude oil density may increase significantly. When the water content reaches 1%, the density of the oil sample may increase by more than 0.15%. Therefore, the first preset oil outlet density ratio ODR1 is set to (1, 1.002) and the second preset oil outlet density ratio ODR2 is set to (1.002, 1.008). If the oil outlet density ratio ODR is less than or equal to the first preset oil outlet density ratio ODR1, then the emulsion film thickness threshold EFT1 is corrected using the first film thickness correction threshold θ1. The corrected emulsion film thickness threshold EFT1' = EFT1 × θ1, where the first film thickness correction threshold θ1 is set to 0.98. If the oil outlet density ratio ODR is greater than the first preset oil outlet density ratio ODR1 and less than or equal to the second preset oil outlet density ratio ODR2, then the emulsion film thickness threshold EFT1 is corrected using the second film thickness correction threshold θ2. The corrected emulsion film thickness threshold EFT1' = EFT1 × θ2, where the second film thickness correction threshold θ2 is set to 0.95. If the oil outlet density ratio ODR is greater than the second preset oil outlet density ratio ODR2, then the emulsion film thickness threshold EFT1 is corrected using the third film thickness correction threshold θ3. The corrected emulsion film thickness threshold EFT1' = EFT1 × θ3, where the third film thickness correction threshold θ3 is set to 0.9.

[0048] Furthermore, based on the revised oil-water separation offset characterization coefficient S, the process of determining whether there is a risk in the separation includes: The risk of separation is determined based on the revised oil-water separation offset characterization coefficient S. If the revised oil-water separation offset characterization coefficient S is less than or equal to the preset oil-water separation offset characterization coefficient, it is determined that there is a risk of separation, and the PID controller proportional band is corrected based on the number of times the PID controller output control signal is corrected for each component within this cycle. If the revised oil-water separation offset characterization coefficient S is greater than the preset oil-water separation offset characterization coefficient, it is determined that there is no risk in the separation, the parameters are maintained, and the detection continues.

[0049] After correcting the above parameters, by re-evaluating the oil-water separation offset characterization coefficient S, it is possible to accurately control whether the current risk has been eliminated and to detect the risk in a timely manner if it has not been eliminated. If the risk still exists after correcting the above parameters, it means that the separation effect cannot be improved by physical adjustment and chemical preparation. At this time, the authenticity of the collected data will be questioned. That is, whether the current anomaly is due to the PID controller being too sensitive, resulting in continuous oscillation or over-adjustment. Therefore, the proportional band of the PID controller is corrected, thereby forming a complete intelligent closed loop from process parameter adjustment, control strategy adjustment to controller parameter self-optimization, to ensure the long-term stability and optimal performance of oil-water interface control.

[0050] Specifically, the process of determining whether there is a risk in the separation based on the revised oil-water separation offset characterization coefficient S includes: The revised oil-water separation offset characterization coefficient S" is compared with the preset oil-water separation offset characterization coefficient S1. If the revised oil-water separation offset characterization coefficient S" is less than or equal to the preset oil-water separation offset characterization coefficient S1, then it is determined that there is a risk of separation, and the PID controller proportional band is corrected based on the number of times the PID controller output control signal is corrected for each component within this cycle. If the revised oil-water separation offset characterization coefficient S" is greater than the preset oil-water separation offset characterization coefficient S1, then it is determined that there is no risk in the separation, the parameters are maintained, and the detection continues.

[0051] Furthermore, the process of correcting the proportional band of the PID controller based on the number of times the PID controller outputs control signals to correct each component within this cycle includes: The PID automatic correction frequency is determined based on the number of times the PID controller outputs control signals to correct each component within this cycle. The proportional band is increased based on the PID automatic correction frequency, and the increase in the proportional band is proportional to the PID automatic correction frequency.

[0052] The PID autocorrection frequency can effectively measure the sensitivity of the current PID controller. When the correction frequency is too high, it indicates that the controller may be in an unstable state of oversensitivity due to the narrow proportional band. Its continuous oscillation will seriously disrupt the static environment required for the stability of the oil-water interface. At this time, the system weakens the controller's response intensity by increasing the proportional band proportionally, thereby accurately suppressing the oscillation. This design realizes the automatic correction of the internal parameters of the PID controller, completing a complete closed loop from process adjustment to control system self-optimization, fundamentally ensuring the long-term robustness of the separation process.

[0053] Specifically, the process of correcting the proportional band of the PID controller based on the number of times the PID controller outputs control signals to correct each component within this cycle includes: The PID automatic correction frequency (NAC) is determined based on the number of times the PID controller outputs control signals to correct each component within this cycle. The PID auto-correction frequency NAC is compared with the set first preset PID auto-correction frequency NAC1 and second preset PID auto-correction frequency NAC2. It is generally believed that when the PID auto-correction frequency is less than 5 times per minute, the system is allowed to be stable. When the correction frequency reaches 5-10 times per minute, it indicates that the current system may have a large reaction to minor disturbances. When the correction frequency is greater than 10 times per minute, it is believed that the current PID controller may be oversensitive. Therefore, the first preset PID auto-correction frequency NAC1 is set to [5, 10 min / time] and the second preset PID auto-correction frequency NAC2 is set to (10, 20 min / time). If the PID auto-correction frequency NAC is less than or equal to the first preset PID auto-correction frequency NAC1, then the proportional band PB is corrected using the first proportional band correction coefficient λ1, and the corrected proportional band PB' = PB × λ1, wherein the first proportional band correction coefficient λ1 is set to 1.02. If the PID auto-correction frequency NAC is greater than the first preset PID auto-correction frequency NAC1 and less than or equal to the second preset PID auto-correction frequency NAC2, then the proportional band PB is corrected using the second proportional band correction coefficient λ2, and the corrected proportional band PB' = PB × λ2, wherein the second proportional band correction coefficient λ2 is set to 1.05. If the PID auto-correction frequency NAC is greater than the second preset PID auto-correction frequency NAC2, then the proportional band PB is corrected using the third proportional band correction coefficient λ3. The corrected proportional band PB' = PB × λ3, where the third proportional band correction coefficient λ3 is set to 1.09.

[0054] Furthermore, based on the revised oil-water separation offset characterization coefficient S, the process of determining whether there is a risk in the separation includes: Based on the revised oil-water separation offset characterization coefficient S, determine whether there is a risk in the separation process; If the oil-water separation offset characterization coefficient S after another correction is less than or equal to the preset oil-water separation offset characterization coefficient, then it is determined that the measurement signal is drifting, there is a risk of separation, and a measurement signal drift warning is output. In addition, the integral time in the PID controller is increased based on the ratio of the interface height standard deviation to the preset interface height standard deviation. If the revised oil-water separation offset characterization coefficient S is greater than the preset oil-water separation offset characterization coefficient, it is determined that there is no risk to the separation, the parameters are maintained and the detection continues. The standard deviation of the interface height refers to the standard deviation of the height of the oil-water interface within the current period.

[0055] If the separation effect still does not improve after the system has successively ruled out all possibilities such as process load, separation temperature, emulsion layer state, and controller parameter misalignment, the root cause can be diagnosed as signal drift of the sensor measuring the oil-water interface. At this time, the system issues a warning to notify manual instrument maintenance. Meanwhile, the capacitor array drift may be due to the complex composition of crude oil. Therefore, the integral time is synchronously corrected to reduce the sensitivity and response intensity of the capacitor array to such high-frequency, erratic drift signals. This transforms the risk of rapid integral saturation that may have caused violent valve action into a slow and gentle adjustment, thereby optimizing its adaptability to different crude oils and improving the oil-water separation effect.

[0056] Specifically, the process of determining whether there is a risk in the separation based on the revised oil-water separation offset characterization coefficient S includes: The revised oil-water separation offset characterization coefficient S ag Compare with the preset oil-water separation offset characterization coefficient S1; If the oil-water separation offset characterization coefficient S is corrected again ag If the measured signal drift is less than or equal to the preset oil-water separation offset characterization coefficient S1, then the measurement signal is determined to be drifting, separation is at risk, a measurement signal drift warning is output, and the integral time in the PID controller is increased based on the ratio of the interface height standard deviation to the preset interface height standard deviation. If the oil-water separation offset characterization coefficient S is corrected again ag If the value is greater than the preset oil-water separation offset characterization coefficient S1, it is determined that there is no risk to the separation, the parameter is maintained and the detection continues.

[0057] Furthermore, the process of increasing the integral time in the PID controller based on the ratio of the interface height standard deviation to the preset interface height standard deviation includes: The interface height standard deviation ratio is determined based on the ratio of the interface height standard deviation to the preset interface height standard deviation, and the integration time is increased based on the interface height standard deviation ratio, wherein the increase in integration time is proportional to the interface height standard deviation ratio.

[0058] The ratio of interface height standard deviation reflects the severity of measurement signal instability. Based on this ratio, and by dynamically increasing the integral time of the PID controller in a proportional relationship, this invention can adaptively reduce the integral action of the controller according to the severity of the fault. When the signal is slightly abnormal, the integral action is only moderately reduced to maintain control accuracy; while when the signal is severely unreliable, the integral action is significantly suppressed, causing the control system to switch from a precise tracking mode to a fault-tolerant mode centered on stability, effectively avoiding extreme actuator actions caused by integral saturation. This design achieves a precise match between the severity of the fault and the extent of control strategy degradation, which not only improves the robustness and safety of the system under abnormal sensor conditions, but also provides a quantitative basis for manual intervention, reflecting a shift from passive alarm to active adaptive protection control.

[0059] Specifically, the process of increasing the integral time in the PID controller based on the ratio of the interface height standard deviation to the preset interface height standard deviation includes: The interface height standard deviation ratio (HSR) is determined based on the ratio of the interface height standard deviation to the preset interface height standard deviation. The interface height standard deviation ratio HSR is compared with the first preset interface height standard deviation ratio HSR1 and the second preset interface height standard deviation ratio HSR2. In principle, the specific values ​​of the first preset interface height standard deviation ratio HSR1 and the second preset interface height standard deviation ratio HSR2 are not limited. Technicians can set them according to historical records or specific requirements, which will not be elaborated here.

[0060] If the interface height standard deviation ratio HSR is less than or equal to the first preset interface height standard deviation ratio HSR1, then the integration time IT is corrected using the first integration correction threshold μ1, and the corrected integration time IT' = IT × μ1, wherein the first integration correction threshold μ1 is set to 1.01. If the interface height standard deviation ratio HSR is greater than the first preset interface height standard deviation ratio HSR1 and less than or equal to the second preset interface height standard deviation ratio HSR2, then the integration time IT is corrected using the second integration correction threshold μ2, and the corrected integration time IT' = IT × μ2, wherein the second integration correction threshold μ2 is set to 1.03. If the interface height standard deviation ratio HSR is greater than the second preset interface height standard deviation ratio HSR2, then the integration time IT is corrected using the third integration correction threshold μ3. The corrected integration time IT' = IT × μ1, where the third integration correction threshold μ3 is set to 1.06.

[0061] In summary, this invention provides an optimized control method for the oil-water interface of a crude oil three-phase separator, aiming to solve the problems of hysteresis, emulsion film interference, and insufficient adaptability to complex operating conditions in traditional control technologies for oil-water interface control. This method comprehensively considers multiple key factors such as emulsion film thickness, oil purity, and water purity, and introduces an oil-water separation offset characterization coefficient S, thereby achieving dynamic monitoring and optimized adjustment of the separation process.

[0062] Specifically, this method first separates crude oil based on pre-set separation parameters and dynamically adjusts the separation strategy according to the emulsion film thickness. By collecting real-time purity data of the oil and water output, the oil-water separation deviation characterization coefficient S is periodically calculated to quantify the deviation of the separation effect from the minimum allowable purity, thus identifying separation risks in advance. When a risk is detected, the system automatically corrects the separation parameters, adjusts the primary strategy selection parameters and the control parameters of the PID controller, and issues a notification, thereby achieving precise optimization of the separation process.

[0063] This method further enhances the system's adaptability and stability to complex operating conditions by introducing various correction mechanisms, such as adjusting the inlet valve opening based on the separation offset ratio, adjusting the target temperature value of the temperature controller based on the inlet valve difference, correcting the emulsion film thickness threshold based on the oil outlet density ratio, adjusting the proportional band based on the PID controller correction frequency, and adjusting the integral time based on the interface height standard deviation ratio. These dynamic adjustment strategies not only improve the response speed and control accuracy of the separation process but also optimize the system's energy efficiency and economy, ensuring efficient and stable oil-water separation.

[0064] In summary, this invention provides an intelligent and adaptive oil-water interface optimization control method for crude oil three-phase separators, which can effectively cope with emulsion film interference, complex crude oil composition changes, and potential quality decline risks, significantly improving the stability and efficiency of oil-water separation. It provides an innovative and efficient solution for the field of crude oil pretreatment technology, and has important practical application value and broad market prospects.

[0065] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for optimizing the oil-water interface control in a crude oil three-phase separator, characterized in that, include, Crude oil is separated based on pre-set separation parameters of the three-phase separator; The primary adjustment strategy is determined based on the emulsion film thickness, including automatically adjusting each separation parameter based on the PID controller in the three-phase separator when the emulsion film thickness is less than or equal to the set emulsion film thickness threshold, or increasing the emulsifier injection rate in the separation parameters based on the ratio of the emulsion film thickness to the emulsion film thickness threshold and continuously monitoring when the emulsion film thickness is greater than the emulsion film thickness threshold. Real-time acquisition of oil and water purity data, and periodic calculation of the oil-water separation offset characterization coefficient S based on the average oil purity and average water purity within the current period. ， in, , This is the oil output weighting coefficient. This is the outflow weighting coefficient. This represents the average oil purity during this cycle. This represents the average purity of the effluent during this cycle. Minimum oil purity Minimum effluent purity; Based on the oil-water separation offset characterization coefficient S, determine whether there is a risk in the separation, and when a risk is determined to exist, correct each of the separation parameters, the primary adjustment strategy selection parameters, and the PID controller control parameters, and issue a notification.

2. The oil-water interface optimization control method according to claim 1, characterized in that, The process of determining whether there is a risk in the separation based on the oil-water separation offset characterization coefficient S includes: The oil-water separation offset characterization coefficient S is calculated based on the average oil purity and the average water purity within this cycle. If the oil-water separation offset characterization coefficient S is less than or equal to the preset oil-water separation offset characterization coefficient, it is determined that there is a risk in the separation, and the opening of the oil inlet valve in the separation parameters is corrected based on the ratio of the preset oil-water separation offset characterization coefficient to the oil-water separation offset characterization coefficient S. If the oil-water separation offset characterization coefficient S is greater than the preset oil-water separation offset characterization coefficient, it is determined that there is no risk in the separation, the parameters are maintained and the detection continues; Wherein, the oil purity refers to the proportion of the mass of the oil component in the total mass of the oil sample obtained from the three-phase separator, and the water purity refers to the proportion of the mass of the water component in the total mass of the water sample obtained from the three-phase separator.

3. The oil-water interface optimization control method according to claim 2, characterized in that, The process of correcting the inlet valve opening in the separation parameters based on the ratio of the preset oil-water separation offset characterization coefficient to the oil-water separation offset characterization coefficient S includes: The separation offset ratio is determined based on the ratio of the preset oil-water separation offset characterization coefficient to the oil-water separation offset characterization coefficient S. The opening degree of the oil inlet valve is reduced based on the separation offset ratio, and the reduction in the opening degree of the oil inlet valve is proportional to the separation offset ratio.

4. The oil-water interface optimization control method according to claim 3, characterized in that, The process of correcting the target temperature value of the temperature controller in the separation parameters based on the difference in the opening degree of the inlet valve before and after correction includes: The inlet valve difference is determined based on the difference in the opening degree of the inlet valve before and after the correction, and the target temperature value of the temperature controller is increased based on the inlet valve difference, and the increase in the target temperature value of the temperature controller is proportional to the inlet valve difference.

5. The oil-water interface optimization control method according to claim 4, characterized in that, The process of determining whether there is a risk in the separation based on the corrected oil-water separation offset characterization coefficient S includes: The risk of separation is determined based on the corrected oil-water separation offset characterization coefficient S. If the corrected oil-water separation offset characterization coefficient S is less than or equal to the preset oil-water separation offset characterization coefficient, it is determined that there is a risk in the separation, and the emulsion film thickness threshold is corrected based on the ratio of the average oil outlet density in this cycle to the preset average oil outlet density. If the corrected oil-water separation offset characterization coefficient S is greater than the preset oil-water separation offset characterization coefficient, it is determined that there is no risk in the separation, the parameters are maintained and the detection continues; The emulsion film thickness threshold refers to the maximum thickness of the emulsion film at the oil-water interface inside the three-phase separator when the PID controller in the three-phase separator automatically adjusts the separation parameters. The average oil outlet density refers to the average density of the oil sample separated from the three-phase separator in the current cycle.

6. The oil-water interface optimization control method according to claim 5, characterized in that, The process of correcting the emulsion film thickness threshold based on the ratio of the average oil outlet density during this period to the preset average oil outlet density includes: The oil outlet density ratio is determined based on the ratio of the average oil outlet density during this period to the preset average oil outlet density, and the emulsion film thickness threshold is reduced based on the oil outlet density ratio, with the reduction in the emulsion film thickness threshold being proportional to the oil outlet density ratio.

7. The oil-water interface optimization control method according to claim 6, characterized in that, The process of determining whether there is a risk in the separation based on the revised oil-water separation offset characterization coefficient S includes: The risk of separation is determined based on the revised oil-water separation offset characterization coefficient S. If the revised oil-water separation offset characterization coefficient S is less than or equal to the preset oil-water separation offset characterization coefficient, it is determined that there is a risk of separation, and the PID controller proportional band is corrected based on the number of times the PID controller output control signal is corrected for each component within this cycle. If the revised oil-water separation offset characterization coefficient S is greater than the preset oil-water separation offset characterization coefficient, it is determined that there is no risk in the separation, the parameters are maintained, and the detection continues.

8. The oil-water interface optimization control method according to claim 7, characterized in that, The process of correcting the proportional band of the PID controller based on the number of times the PID controller outputs control signals to correct each component within this cycle includes: The PID automatic correction frequency is determined based on the number of times the PID controller outputs control signals to correct each component within this cycle. The proportional band is increased based on the PID automatic correction frequency, and the increase in the proportional band is proportional to the PID automatic correction frequency.

9. The oil-water interface optimization control method according to claim 8, characterized in that, The process of determining whether there is a risk in the separation based on the revised oil-water separation offset characterization coefficient S includes: Based on the revised oil-water separation offset characterization coefficient S, determine whether there is a risk in the separation process; If the oil-water separation offset characterization coefficient S after another correction is less than or equal to the preset oil-water separation offset characterization coefficient, then it is determined that the measurement signal is drifting, there is a risk of separation, and a measurement signal drift warning is output. In addition, the integral time in the PID controller is increased based on the ratio of the interface height standard deviation to the preset interface height standard deviation. If the revised oil-water separation offset characterization coefficient S is greater than the preset oil-water separation offset characterization coefficient, it is determined that there is no risk to the separation, the parameters are maintained and the detection continues. The interface height standard deviation refers to the standard deviation of the oil-water interface height within the current period.

10. The oil-water interface optimization control method according to claim 9, characterized in that, The process of increasing the integral time in the PID controller based on the ratio of the interface height standard deviation to the preset interface height standard deviation includes: The interface height standard deviation ratio is determined based on the ratio of the interface height standard deviation to the preset interface height standard deviation, and the integration time is increased based on the interface height standard deviation ratio, wherein the increase in integration time is proportional to the interface height standard deviation ratio.

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