Real-time monitoring and feedback regulation and control device for oilfield sewage treatment

Abstract

The invention discloses a real-time monitoring and feedback regulation and control device for oilfield sewage treatment, and belongs to the technical field of sewage treatment. The device comprises a monitoring unit used for collecting multiple water quality parameters and process operation parameters in the oilfield sewage treatment process in real time; the regulation and control unit comprises a medicament adding module, a stirring regulation and control module, a filtering regulation and control module and a water outlet valve control module which are respectively used for adding a demulsifying agent, a flocculating agent and a corrosion inhibitor, regulating stirring parameters, controlling start and stop of a filtering assembly, backwashing and regulating the water outlet flow; the control unit is used for receiving the real-time parameter data transmitted by the monitoring unit, comparing a real-time water quality parameter with a preset threshold value, and generating a regulation and control instruction through the process parameter matching model in combination with a process operation parameter so as to realize closed-loop feedback regulation and control; the auxiliary unit comprises a sewage inlet pipeline, a treatment tank body, a water outlet pipeline and a medicament storage assembly; through multi-unit collaborative design and intelligent technology integration, efficient, intelligent and safe operation of oilfield sewage treatment is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sewage treatment, more particularly to an oilfield sewage treatment real-time monitoring and feedback control device. BACKGROUND

[0002] A large amount of oily sewage is generated during the development of oilfields, which is complex in composition and contains oil, suspended solids, heavy metal ions and residues of various chemical agents. If it is directly discharged or reinjected into the formation, it will cause serious environmental pollution and may also block oil layer pores, affecting the efficiency of oilfield development. Therefore, oilfield sewage treatment is the core link of oilfield surface engineering, and high-efficiency treatment devices are needed to achieve water quality standards and ensure compliance for reinjection or discharge.

[0003] With the acceleration of intelligent development of oilfields, the traditional manual monitoring and manual control mode of sewage treatment has been difficult to meet the efficient and accurate processing needs, and various real-time monitoring and feedback control devices have emerged as the times require. In the prior art, such devices are integrated with water quality sensors, control execution mechanisms and basic control modules, which can realize real-time acquisition and simple control of water quality parameters, and to a certain extent, improve the automation level of sewage treatment and reduce the labor intensity.

[0004] However, in actual oilfield application scenarios, the existing devices still have many technical shortcomings, which seriously affect the continuity, stability and operation and maintenance efficiency of sewage treatment: first, the fault handling capability is weak, and the existing devices mostly only have basic fault alarm function. When the monitoring unit, control unit, etc. (such as sensor failure, metering pump jamming, filter assembly blockage failure, etc.) fails, it cannot automatically take emergency measures, which easily leads to interruption of the sewage treatment process, and further causes water quality exceeding standards, treatment pool overload and other chain problems; at the same time, after the fault occurs, only the existence of the fault can be prompted, and a targeted fault diagnosis report cannot be generated, so the maintenance personnel need to check the fault points one by one on site, the maintenance efficiency is low, and the professional skill requirements for the maintenance personnel are extremely high, which further increases the operation and maintenance cost of oilfield sewage treatment.

[0005] Secondly, the remote control and data application capability is insufficient. The oilfield exploitation area is often wide, and the sewage treatment sites are scattered. The existing devices are mostly single independent operation, lacking centralized control mechanism of multiple devices. The operation and maintenance personnel need to go back and forth between the sites for on-site operation, which is low in operation and maintenance efficiency. Although some devices have simple remote data transmission function, they can only realize the preliminary display of real-time data, lacking the core functions of historical data tracing, fault remote diagnosis and parameter remote modification, and cannot realize unified operation and maintenance management across sites. In addition, the existing devices do not form a perfect data statistics and analysis system, cannot generate multi-dimensional reports based on monitoring data, and are difficult to provide accurate data support for the optimization and adjustment of sewage treatment process, resulting in that the process optimization relies on experience, which is insufficient in scientificity and pertinence, and restricts the further improvement of sewage treatment efficiency.

[0006] Thirdly, the fault tolerance and reliability of the existing device are insufficient. In the face of the complex environment of high temperature, high humidity, much dust and flammable and explosive in the oilfield site, the failure rate is relatively high, and there is no standby operation mode for automatic switching, which further aggravates the risk of interruption of sewage treatment process, cannot guarantee the continuous and stable operation of sewage treatment, and is difficult to adapt to the high-strength and high-reliability sewage treatment demand of oilfield.

[0007] In summary, in view of the technical defects of the existing real-time monitoring and feedback regulation device for oilfield sewage treatment in fault disposal, remote control and data application, it is urgent to develop a device with fault self-diagnosis, automatic standby switching, multi-device centralized control and data-based process optimization support capability, so as to improve the stability, operation and maintenance efficiency and scientificity of process optimization of oilfield sewage treatment, and meet the actual needs of intelligent development of oilfield. Therefore, we propose a real-time monitoring and feedback regulation device for oilfield sewage treatment. SUMMARY

[0008] The purpose of the present application is to provide a real-time monitoring and feedback regulation device for oilfield sewage treatment to solve the problems raised in the background art.

[0009] To achieve the above purpose, the present application provides the following technical scheme: A real-time monitoring and feedback regulation device for oilfield sewage treatment, comprising: A monitoring unit for real-time acquisition of multiple water quality parameters and process operation parameters in the oilfield sewage treatment process, the water quality parameters at least including oil content, suspended solids concentration, COD, pH value and salinity, and the process operation parameters at least including treatment pool liquid level, reagent dosage, stirring speed and filter assembly pressure difference. The sensor of the monitoring unit has a wide temperature adaptation capability of-40℃~60℃, a data acquisition frequency of 1 time / second, a data error of not more than ±2%, and a daily timing automatic calibration function. The control unit includes modules for chemical dosing, stirring control, filtration control, and effluent valve control, which are used to add demulsifiers, flocculants and corrosion inhibitors, adjust stirring parameters, control the start and stop of the filter components and backwashing, and adjust the effluent flow rate, respectively. The control unit is electrically connected to both the monitoring unit and the control unit. It has a built-in preset water quality standard threshold and process parameter matching model. This model receives real-time parameter data from the monitoring unit, compares the real-time water quality parameters with the preset thresholds, and generates control commands based on the process operating parameters and the process parameter matching model. These commands are then sent to the control unit to achieve closed-loop feedback control. The sensor housings and reagent dosing modules of both the control and monitoring units are designed with explosion-proof sealing, with an explosion-proof rating of no less than Ex d IIB T4 Gb and a protection rating of no less than IP65. The auxiliary unit includes a sewage inlet pipe, a treatment tank, an outlet pipe, and a reagent storage component. The sewage inlet pipe is connected to the input end of the treatment tank, and the outlet pipe is located at the output end of the treatment tank and connected in series with the outlet valve control module. The reagent storage component is connected to the reagent dosing module through a pipe. The detection probe of the monitoring unit extends into the interior of the treatment tank and the outlet pipe. The stirring control module and the filtration control module are installed on the treatment tank. The exterior of the treatment tank is equipped with a polyurethane foam insulation layer with a thickness of not less than 50mm. The interior is divided into a pretreatment zone, a reaction zone, a sedimentation zone, and a filtration zone, with each zone separated by a guide plate with flow guide holes.

[0010] Preferably, the monitoring unit includes a multi-parameter water quality sensor group and a liquid level sensor, a flow sensor, a differential pressure sensor, and a reagent metering sensor; the multi-parameter water quality sensor group includes an online fluorescence method oil content sensor, a potassium dichromate digestion-colorimetric method COD sensor, etc., and the detection probe of each water quality sensor is equipped with an anti-fouling coating. Each sensor detects its corresponding parameter and transmits it to the control unit.

[0011] Preferably, the reagent dosing module includes three independent reagent storage tanks, a plunger-type metering pump with a metering accuracy of ±0.3%, and a dosing pipeline; the dosing pipeline is equipped with an atomizing nozzle at the end, extending to the stirring area of ​​the treatment tank; the reagent storage component is equipped with a leak-proof tray and a liquid level alarm device, which triggers an alarm and suspends dosing when the liquid level in the tank exceeds 10% to 90% of the tank capacity.

[0012] Preferably, the stirring control module includes a variable frequency motor, a stirring shaft, and a stirring paddle; The control unit adjusts the stirring speed continuously within the range of 50-500 r / min via a frequency converter, with a stirring speed control accuracy of ±5 r / min. It can also automatically switch between fast mixing mode and slow flocculation mode according to changes in water quality parameters. The speed in fast mixing mode is 300-500 r / min, and the speed in slow flocculation mode is 50-150 r / min.

[0013] Preferably, the filtration control module includes a modified fiber ball filter element, a backwash pump, and a backwash pipeline; The control unit controls the backwashing action based on the pressure difference signal detected by the differential pressure sensor. When the pressure difference exceeds 0.15MPa, the backwashing pump is automatically started. The backwashing pressure of the backwashing pump is 0.5~0.8MPa, and the backwashing process lasts for 5-10 minutes. After the backwashing is completed, the filtration operation is automatically restored.

[0014] Preferably, the control unit includes a main control module, a data storage module, a communication module, and an alarm module; the main control module has a built-in process parameter matching model based on the PID fuzzy control algorithm, which can optimize the control parameters; the data storage module has a storage capacity of not less than 1TB and a data retention period of not less than 1 year; the communication module supports 4G / 5G and Ethernet communication and can transmit data to a remote platform; when the water quality exceeds the standard or the equipment fails, the audible and visual alarm module triggers an alarm.

[0015] Preferably, the treatment tank is made of corrosion-resistant stainless steel, with an anti-scaling coating on the inner wall, and is also equipped with an emergency discharge pipeline and a pressure safety valve for over-level discharge. When the liquid level in the tank exceeds 95% of the tank capacity or the pressure exceeds 0.3MPa, the emergency discharge pipeline and safety valve will be opened automatically. The device also includes an emergency power-off module, which cuts off the power supply to non-explosion-proof areas when the concentration of flammable and explosive gas at the site is detected to be ≥1%VOL.

[0016] Preferably, it also includes a self-cleaning module, which includes a high-pressure flushing nozzle, a cleaning pump, a dedicated cleaning fluid storage tank, and a waste liquid recovery pipeline; the dedicated cleaning fluid is made by mixing citric acid and deionized water in a 1:10 ratio; the self-cleaning module can be started every 2 hours or when the sensor data error exceeds 5%, using a pressure of 0.2~0.3MPa to flush the detection probe and a pressure of 0.5~0.8MPa to flush the filter components, and the waste liquid after flushing is returned to the front end of the treatment tank.

[0017] Preferably, the preset water quality standard threshold can be customized according to the requirements of oilfield wastewater reinjection or discharge. Under the reinjection standard, the oil content is ≤5mg / L and the suspended solids concentration is ≤10mg / L. Under the discharge standard, the oil content is ≤1mg / L and the suspended solids concentration is ≤5mg / L and the COD is ≤50mg / L. The control unit has a built-in temperature compensation module that can automatically calibrate monitoring data and control commands according to the ambient temperature, thus avoiding the impact of temperature and humidity on operating accuracy.

[0018] Preferably, the control unit has a built-in fault self-diagnosis module, which automatically switches to standby operation mode and generates maintenance prompts when a fault is detected; the remote monitoring platform can realize centralized management and control of multiple devices, supports real-time data visualization, remote control and fault diagnosis functions, and can generate multi-dimensional process optimization reports.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention achieves efficient, intelligent, and safe operation of oilfield wastewater treatment through multi-unit collaborative design and intelligent technology integration. The fault self-diagnosis and backup mode switching mechanism effectively avoids process interruptions caused by single faults, ensuring continuous wastewater treatment. Combined with maintenance prompts, it significantly shortens fault diagnosis and repair time, substantially reducing operation and maintenance costs. The remote monitoring platform supports centralized management of multiple devices, accurately adapting to the dispersed layout of multiple oilfield sites. Combined with real-time data visualization, remote control, and fault diagnosis functions, it greatly improves operation and maintenance efficiency. The generated multi-dimensional process optimization reports also provide accurate data support for managers, assisting in continuous improvement of wastewater treatment processes and enhancing treatment effectiveness and economic efficiency. A closed-loop automated feedback control system further enhances the system's capabilities. Combining high-precision monitoring and optimization algorithms, the system achieves fully automated linkage of the "monitoring-analysis-control" process, avoiding water quality exceeding standards due to lag in manual control and ensuring stable effluent compliance. Specialized designs such as wide temperature adaptability, explosion-proof sealing, and emergency protection perfectly adapt to the harsh environments of oilfields, including high and low temperatures, flammable and explosive materials, and high dust levels, improving the safety and lifespan of the equipment. Detailed designs such as self-cleaning, precise reagent dosing, and segmented treatment not only improve treatment accuracy and efficiency but also reduce reagent waste and secondary environmental pollution, balancing treatment effectiveness and environmental benefits to fully meet the diverse needs of oilfield wastewater reinjection or discharge. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0022] Example: Please see Figure 1 A real-time monitoring and feedback control device for oilfield wastewater treatment, comprising: The monitoring unit is used to collect multiple water quality parameters and process operation parameters in real time during the oilfield wastewater treatment process. Water quality parameters include at least oil content, suspended solids concentration, COD, pH value, and salinity. Process operation parameters include at least treatment tank level, reagent dosage, stirring speed, and pressure difference of the filter components. The monitoring unit's sensors have wide temperature adaptability, operating stably in environments ranging from -40℃ to 60℃. Data acquisition frequency is 1 time / second, with a data error not exceeding ±2%. It also features an automatic calibration function for daily comparison with standard samples. The wide temperature adaptability allows it to withstand harsh outdoor environments of oilfields, ensuring stable monitoring data. High-frequency acquisition and low-error characteristics enable precise control of water quality and process parameters, providing reliable data support for subsequent regulation. The automatic calibration function requires no manual intervention, reducing operation and maintenance costs and avoiding monitoring deviations caused by sensor drift.

[0023] The control unit includes a reagent dosing module, a stirring control module, a filtration control module, and an effluent valve control module. The reagent dosing module is used to add demulsifiers, flocculants, and corrosion inhibitors to the treatment system. The stirring control module is used to adjust the speed and duration of the stirring mechanism in the treatment tank. The filtration control module is used to control the start, stop, and backwashing of the filtration components. The effluent valve control module is used to regulate the effluent flow rate. The control unit achieves precise control of the entire wastewater treatment process through the collaboration of multiple modules. The reagent dosing specifically addresses the demulsification, flocculation, and equipment corrosion problems of oily wastewater. The stirring parameter adjustment ensures sufficient reaction. The filtration backwashing ensures filtration efficiency. The effluent valve control precisely controls the treatment rhythm, thereby improving the overall wastewater treatment effect and efficiency.

[0024] The control unit is electrically connected to both the monitoring unit and the control unit. It incorporates a preset water quality standard threshold and a process parameter matching model. This control unit receives real-time parameter data from the monitoring unit, compares the real-time water quality parameters with the preset thresholds, and generates control commands based on the process operating parameters and the process parameter matching model. These commands are then sent to the control unit to achieve closed-loop feedback control. The sensor housings and reagent dosing modules of the control and monitoring units all feature explosion-proof sealing designs with an explosion-proof rating no lower than Ex d IIB T4 Gb and a protection rating no lower than IP65. The closed-loop feedback control achieves automated linkage between monitoring, analysis, and control, avoiding water quality exceedances caused by lag in manual control. The explosion-proof sealing and high protection rating design are suitable for flammable, explosive, dusty, and high-humidity environments in oil fields, improving the safety and service life of the equipment and reducing the risk of safety accidents.

[0025] The auxiliary unit includes a wastewater inlet pipe, a treatment tank, an outlet pipe, and a reagent storage component. The wastewater inlet pipe connects to the input end of the treatment tank, and the outlet pipe is located at the output end of the treatment tank and connected in series with the outlet valve control module. The reagent storage component is connected to the reagent dosing module via a pipe. The detection probe of the monitoring unit extends into the interior of the treatment tank and the outlet pipe. The stirring control module and the filtration control module are installed on the treatment tank. The exterior of the treatment tank is covered with a polyurethane foam insulation layer with a thickness of not less than 50mm. The interior is divided into a pretreatment zone, a reaction zone, a sedimentation zone, and a filtration zone, with each zone separated by a guide plate with flow-guiding holes. The segmented tank design allows wastewater to complete each treatment stage sequentially, improving treatment continuity and effectiveness. The guide plate structure prevents short-circuit flow of wastewater, ensuring reaction time. The insulation layer maintains a stable temperature inside the tank, preventing low-temperature environments from affecting reagent reaction efficiency. The rational layout of each module ensures accurate coverage of monitoring and control, improving the overall synergy of the device.

[0026] In this application, the monitoring unit includes a multi-parameter water quality sensor group, a level sensor, a flow sensor, a differential pressure sensor, and a reagent metering sensor. The multi-parameter water quality sensor group includes an online fluorescence oil content sensor, a suspended solids sensor, a potassium dichromate digestion-colorimetric COD sensor, a pH sensor, and a mineralization sensor. Each sensor's probe is equipped with an anti-fouling coating. The level sensor is installed on the inner wall of the treatment tank, the flow sensors are installed in the wastewater inlet and outlet pipes, the differential pressure sensor is installed at both ends of the filter assembly, and the reagent metering sensor is installed in the output pipe of the reagent dosing module. These sensors are used to monitor the wastewater level, inlet and outlet flow rates, the pressure difference between the filter assembly inlet and outlet, and the reagent dosage in real time. The specialized sensor types ensure the accuracy of core water quality parameters such as oil content and COD, meeting the stringent monitoring requirements of oilfield wastewater treatment. The anti-fouling coating prevents oil and suspended solids from adhering to the probes, extending sensor lifespan and reducing cleaning and maintenance frequency. The multi-type sensors comprehensively cover water quality and process parameters, providing comprehensive data input to the control unit and ensuring the scientific nature of control decisions.

[0027] In this application, the reagent dosing module includes three independent reagent storage tanks, a plunger metering pump, and a dosing pipeline. The metering accuracy of the plunger metering pump is ±0.3%. The three reagent storage tanks are used to store demulsifier, flocculant, and corrosion inhibitor, respectively. The output end of each reagent storage tank is connected in series with the corresponding metering pump, and the metering pump is electrically connected to the control unit, which can adjust the dosing flow rate according to the control command. The output end of the dosing pipeline extends to the stirring area inside the treatment tank, and multiple atomizing nozzles are installed at the end. The reagent storage component is also equipped with a leak-proof tray and a liquid level alarm device. When the liquid level of the reagent storage tank is lower than 10% of the tank capacity or higher than 90% of the tank capacity, the alarm is automatically triggered and the reagent dosing is suspended.

[0028] Among them, independent storage tanks avoid mixing and contamination of different agents and improve the effectiveness of agents; high-precision metering pumps enable precise control of agent dosage, avoiding waste or insufficient dosage that leads to poor treatment results; atomizing nozzles ensure uniform dispersion of agents, and combined with the stirring zone, improve the mixing efficiency of agents and wastewater; leak-proof and liquid level alarm designs prevent agent leakage from polluting the environment, while avoiding insufficient or overflowing agents from affecting the treatment process, thus improving the safety and stability of the equipment operation.

[0029] In this application, the stirring control module includes a variable frequency motor, a stirring shaft, and a stirring paddle. The variable frequency motor is installed on the top of the treatment tank. One end of the stirring shaft is connected to the output end of the variable frequency motor, and the other end extends into the treatment tank and is fixedly connected to the stirring paddle. The control unit is electrically connected to the variable frequency motor through a variable frequency controller, and can continuously adjust the stirring speed within the range of 50-500 r / min, with a stirring speed control accuracy of ±5 r / min. It can also automatically switch between a fast mixing mode and a slow flocculation mode according to changes in water quality parameters. The speed in the fast mixing mode is 300-500 r / min, and the speed in the slow flocculation mode is 50-150 r / min. The wide range of adjustable speeds adapts to the needs of different treatment stages. The fast mixing mode ensures rapid and uniform mixing of the reagent and the wastewater, while the slow flocculation mode ensures stable floc growth and improves the solid-liquid separation effect. High-precision speed control avoids over- or under-stirring, which affects treatment efficiency. Automatic mode switching realizes intelligent adaptation of stirring parameters without manual intervention, improving the automation level of the device.

[0030] In this application, the filtration control module includes a modified fiber ball filter element, a backwash pump, and a backwash pipeline. The backwash pump is connected in series in the backwash pipeline, with one end connected to the outlet pipeline and the other end connected to the output end of the filter element. The control unit controls the backwashing action based on the pressure difference signal detected by the differential pressure sensor. When the pressure difference exceeds 0.15 MPa, the backwash pump is automatically started. The backwash pressure of the backwash pump is 0.5~0.8 MPa, and the backwashing process lasts for 5-10 minutes. After the backwash is completed, the filtration operation is automatically restored. The modified fiber ball filter element has high filtration accuracy and dirt holding capacity, and can efficiently remove suspended solids and residual oil from sewage. The automatic backwashing function is automatically triggered based on the pressure difference, without the need for manual judgment, and promptly removes impurities trapped by the filter element, restores filtration efficiency, and avoids processing interruption caused by component blockage. Reasonable backwashing pressure and duration ensure the backwashing effect while avoiding damage to the filter element and extending its service life.

[0031] In this application, the control unit includes a main control module, a data storage module, a communication module, and an alarm module. The main control module adopts a PLC controller with a built-in process parameter matching model. The process parameter matching model is constructed based on the PID control algorithm combined with fuzzy control logic, which can automatically optimize the control parameters according to the real-time water quality parameter deviation. The PID fuzzy control algorithm enables the control parameters to be dynamically optimized according to the water quality deviation, thereby improving the accuracy and adaptability of the control.

[0032] The data storage module is used to store real-time monitoring data, control commands, and historical operating data. The storage capacity is no less than 1TB, and the data retention period is no less than 1 year. The large-capacity data storage enables full-cycle data traceability and provides data support for process optimization and fault diagnosis.

[0033] The communication module supports 4G / 5G and Ethernet communication, which can transmit real-time data to the remote monitoring platform and receive remote control commands; multi-mode communication ensures stable remote data transmission and enables remote monitoring of the device.

[0034] The alarm module includes an audible and visual alarm. When water quality parameters exceed the standard or equipment malfunctions, the alarm is automatically triggered and the alarm information is synchronized to the remote monitoring platform. Timely audible and visual alarms can quickly remind maintenance personnel to handle abnormalities, prevent problems from escalating, and reduce losses.

[0035] In this application, the treatment tank is made of corrosion-resistant stainless steel, with an anti-scaling coating on the inner wall. It is also equipped with an emergency discharge pipeline and a pressure safety valve for exceeding the liquid level. When the liquid level in the tank exceeds 95% of the tank capacity or the pressure exceeds 0.3MPa, the emergency discharge pipeline and safety valve will be automatically opened. The corrosion-resistant material and anti-scaling coating can resist the corrosion and scaling of oilfield sewage, extend the service life of the tank, and reduce maintenance costs.

[0036] The device also includes an emergency power-off module. When the concentration of flammable and explosive gas at the site is detected to be ≥1%VOL (such as methane), the power supply to non-explosion-proof areas is automatically cut off, while only emergency communication and alarm functions are retained. The emergency discharge and pressure safety structure prevents the pool from being damaged due to overload, ensuring the safe operation of the device. The emergency power-off module is designed for the flammable and explosive environment of oil fields, and can quickly cut off the risky power supply, prevent safety accidents, and improve the safety protection level of the device.

[0037] This application also includes a self-cleaning module, which comprises a high-pressure flushing nozzle, a cleaning pump, a cleaning fluid storage tank, and a waste liquid recovery pipeline. The cleaning fluid storage tank contains a dedicated cleaning fluid, which is made from citric acid and deionized water in a 1:10 ratio. The high-pressure flushing nozzle is installed on the surface of the detection probe and filter assembly of the monitoring unit. The control unit can initiate self-cleaning at regular intervals, with a default interval of every 2 hours. Self-cleaning can also be initiated based on sensor data error, starting when the sensor data error exceeds 5%. The detection probe is flushed at a pressure of 0.2~0.3 MPa, and the filter assembly at a pressure of 0.5~0.8 MPa. The flushing waste liquid is returned to the front end of the treatment tank through the recovery pipeline to avoid secondary pollution. The combination of timed and on-demand cleaning effectively removes dirt from the surface of the probe and filter assembly, preventing dirt from affecting monitoring accuracy and filtration efficiency. The dedicated cleaning fluid is both effective and gentle, and will not damage equipment components. The waste liquid return design prevents cleaning wastewater from polluting the environment, while simultaneously enabling wastewater reprocessing, improving water resource utilization, and reducing environmental pressure.

[0038] In this application, the preset water quality standard thresholds can be customized according to the requirements of oilfield wastewater reinjection or discharge. Under the reinjection standard, the oil content is ≤5mg / L and the suspended solids concentration is ≤10mg / L. Under the discharge standard, the oil content is ≤1mg / L, the suspended solids concentration is ≤5mg / L, and the COD is ≤50mg / L. The control unit has a built-in temperature compensation module, which can automatically calibrate monitoring data and control commands according to the ambient temperature, avoiding the influence of temperature and humidity on the operational accuracy. The customizable thresholds can adapt to different needs of oilfield wastewater reinjection or discharge, improving the versatility of the device. The temperature compensation module can offset the influence of changes in ambient temperature and humidity on the monitoring and control accuracy, ensuring that the preset water quality standards can still be stably achieved in complex environments, improving the environmental adaptability and operational reliability of the device.

[0039] In this application, the control unit also incorporates a built-in fault self-diagnosis module, which can monitor the operating status of each unit in real time. When a fault is detected, it automatically switches to standby mode and generates a fault diagnosis report highlighting key maintenance points. The remote monitoring platform enables centralized management of multiple devices, supports real-time data visualization, historical data tracing, remote parameter modification, and remote fault diagnosis, and can generate daily, weekly, and monthly reports, providing data support for process optimization. Fault self-diagnosis and standby mode switching prevent a single fault from interrupting the entire treatment process, ensuring continuous wastewater treatment. Maintenance prompts shorten troubleshooting and repair time, reducing operation and maintenance costs. Centralized management of multiple devices adapts to the needs of dispersed layouts of multiple oilfield sites, improving operation and maintenance efficiency. Process optimization reports provide data support for management personnel, assisting in continuous improvement of wastewater treatment processes and further enhancing treatment effectiveness and economic efficiency.

[0040] Example 1 This embodiment is used to treat produced water from an oilfield. The produced water has an average oil content of 35 mg / L, an average suspended solids concentration of 40 mg / L, an average COD of 120 mg / L, a mineralization of 8000 mg / L, and a pH value fluctuating between 6.5 and 8.5. The treatment objective is to meet the oilfield reinjection standards (oil content ≤ 5 mg / L, suspended solids concentration ≤ 10 mg / L).

[0041] I. Specific Structure of the Device The real-time monitoring and feedback control device for oilfield wastewater treatment described in this embodiment includes a monitoring unit, a control unit, a control unit, an auxiliary unit, a self-cleaning module, and an emergency module. The specific structure and assembly of each unit are as follows: 1. Monitoring Unit The monitoring unit includes a multi-parameter water quality sensor group, a liquid level sensor, a flow sensor, a differential pressure sensor, and a reagent metering sensor. Each sensor adopts an explosion-proof sealed design with an IP65 protection rating, suitable for the harsh outdoor environment of oil fields. Among them: Multi-parameter water quality sensor array: The online fluorescence method oil content sensor is model OSD600, installed in the middle of the reaction zone of the treatment tank and the effluent pipeline, with a detection range of 0-100mg / L and an accuracy of ±0.1mg / L; the potassium dichromate digestion-colorimetric method COD sensor is model CODmax II, installed in the effluent pipeline, with a detection range of 0-500mg / L and a digestion temperature of 175℃; the suspended solids sensor is model TSS-300, the pH sensor is model pH300, and the mineralization sensor is model Cond3200, all installed at the outlet of the pretreatment zone of the treatment tank. The detection probes of each sensor are coated with polytetrafluoroethylene antifouling coating to prevent the adhesion of oil and suspended solids.

[0042] The liquid level sensor is an ultrasonic level gauge, installed in the middle of the side wall of the treatment tank, with a measurement range of 0-5m and an accuracy of ±1mm, to detect the liquid level in the tank in real time; the flow sensor is an electromagnetic flow meter, installed on the sewage inlet and outlet pipes respectively, with a range of 0-100m³ / h and an accuracy of ±0.5%; the differential pressure sensor is a differential pressure transmitter, installed at both ends of the filter assembly, with a measurement range of 0-0.5MPa and an accuracy of ±0.001MPa; the reagent metering sensor is a mass flow meter, installed on the output pipes of the three reagent dosing modules respectively, with a range of 0-50L / h and an accuracy of ±0.3%.

[0043] All sensor data is acquired at a frequency of 1 time / second. The sensors are automatically compared and calibrated with standard samples at 2:00 AM every day. The calibration error is controlled within ±2%. The sensors also have a wide temperature range of -40℃ to 60℃, which can cope with the low temperature in winter and the high temperature in summer in oil fields.

[0044] 2. Control Unit The reagent dosing module includes three 5m³ stainless steel reagent storage tanks, which store demulsifier (model SP-169), flocculant (model PAC-28), and corrosion inhibitor (model BH-901), respectively. Each storage tank has a plunger metering pump connected in series at its output end, model GM0100, with a metering accuracy of ±0.3% and a dosing flow range of 0-50L / h, and is electrically connected to the control unit. The dosing pipeline is made of stainless steel and is equipped with four sets of atomizing nozzles at the end, extending to the stirring area of ​​the reaction zone in the treatment tank to ensure uniform dispersion of the reagents.

[0045] Stirring and control module: The variable frequency motor is model YVP200L-4 with a power of 30kW, and is installed at the center of the top of the treatment tank; the stirring shaft is made of stainless steel, with a length of 3.5m, and a double-layer propulsion stirring paddle with a blade diameter of 1.2m is fixedly connected to the bottom; the control unit is connected to the motor through a variable frequency controller of model VFD037M43A, and the stirring speed is continuously adjustable in the range of 50-500r / min with a control accuracy of ±5r / min. It can automatically switch between fast mixing and slow flocculation modes.

[0046] Filtration control module: The filter element adopts a modified fiber ball filter element with a filtration accuracy of 10μm and a dirt holding capacity of 8kg / m³, and is installed in the filtration area of ​​the treatment tank; the backwash pump is model ISG50-160 with a head of 32m, a flow rate of 15m³ / h, and a backwashing pressure of 0.5~0.8MPa; one end of the backwash pipeline is connected to the outlet pipeline, and the other end is connected to the output end of the filter element. The pipeline is equipped with a solenoid valve, which is controlled by the control unit to start and stop.

[0047] Outlet valve control module: an electric regulating ball valve, model VQ641F-16C, is selected and installed on the outlet pipeline. The adjustment range is 0-100m³ / h. It is electrically connected to the control unit and automatically adjusts the outlet flow rate according to the processing load.

[0048] 3. Control Unit The control unit adopts an integrated explosion-proof control cabinet with an explosion-proof rating of Ex d IIB T4 Gb, and includes a built-in PLC main control module, data storage module, communication module, and alarm module. Among them: The PLC main control module uses a Siemens S7-1500, which has a built-in process parameter matching model based on PID fuzzy control algorithm. It can automatically optimize and control parameters according to the deviation of water quality parameters. The data storage module uses a 2TB industrial solid-state drive, which can retain data for no less than one year and supports encrypted storage and historical data traceability.

[0049] The communication module integrates a 4G / 5G dual-mode module (model EC200S) and an Ethernet module, which can transmit real-time data to the remote monitoring platform with a communication delay of ≤1s. It also supports remote modification of control parameters. The alarm module includes an audible and visual alarm (model LTE-1101) and an SMS alarm module. When the water quality exceeds the standard or the equipment fails, the audible and visual alarm is triggered simultaneously and SMS notifications are sent to the mobile phones of 3 maintenance personnel.

[0050] The control unit has a built-in temperature compensation module that collects ambient temperature in real time and automatically calibrates monitoring data and control commands. It also integrates a fault self-diagnosis module that can monitor the operating current, voltage and signal transmission status of each unit. It has a built-in backup PLC module that automatically switches to backup operation mode within 1 second in case of a fault.

[0051] 4. Auxiliary Unit The treatment tank is made of 304 corrosion-resistant stainless steel with a volume of 50m³. The inner wall is coated with a 2mm thick polyurea anti-scaling coating; the exterior is insulated with a 50mm thick polyurethane foam layer and protected by a color steel plate. The tank is internally divided along the water flow direction into a pretreatment zone (10m³), a reaction zone (20m³), a sedimentation zone (15m³), and a filtration zone (5m³). These zones are separated by stainless steel guide plates with 50mm diameter holes spaced 150mm apart, ensuring orderly wastewater flow and uniform retention time.

[0052] Both the sewage inlet and outlet pipelines are made of DN150 stainless steel. The chemical storage components are equipped with leak-proof trays with a volume of 0.5m³ and a leak detection sensor at the bottom. The treatment tank is equipped with an emergency discharge pipeline (DN80) for exceeding the liquid level and a pressure safety valve (model A28H-16C) with an opening pressure of 0.3MPa.

[0053] 5. Self-cleaning module and emergency module The self-cleaning module includes a high-pressure flushing nozzle, a cleaning pump (model ISG32-160), a 0.3m³ cleaning fluid storage tank, and a waste liquid recovery pipeline. The special cleaning fluid is made by mixing citric acid and deionized water in a 1:10 ratio. The high-pressure flushing nozzles are installed on the surfaces of each sensor probe and filter assembly. The flushing pressure of the nozzles for the probes is 0.2~0.3MPa, and the flushing pressure of the nozzles for the filter assemblies is 0.5~0.8MPa. The waste liquid recovery pipeline is connected to the front end of the pretreatment area.

[0054] The emergency power-off module uses an explosion-proof gas detection controller (model QB2000) and is equipped with a methane sensor. When the on-site methane concentration is detected to be ≥1%VOL, the power supply to non-explosion-proof areas is automatically cut off, while only emergency communication and alarm functions are retained.

[0055] II. Equipment Operation Flow When this device is in operation, real-time monitoring and feedback control of oilfield wastewater treatment are achieved by following these steps: 1. Wastewater introduction: Oilfield produced water enters the pretreatment area of ​​the treatment tank through the wastewater inlet pipeline. The inlet pipeline flow sensor collects the inlet flow rate in real time (set to 50m³ / h) and transmits the data to the control unit.

[0056] 2. Real-time monitoring: All sensors collect parameters synchronously. Sensors in the pretreatment zone collect data on oil content, suspended solids concentration, COD, pH value, mineralization, and liquid level in the influent; chemical metering sensors collect data on the dosage of demulsifier, flocculant, and corrosion inhibitor; differential pressure sensors collect data on the pressure difference between the inlet and outlet of the filter assembly; all data is transmitted to the control unit in real time, with a data acquisition frequency of 1 time / second.

[0057] 3. Closed-loop control: The control unit compares real-time water quality parameters with reinjection standard thresholds (oil content ≤ 5 mg / L, suspended solids concentration ≤ 10 mg / L), and generates control commands through a process parameter matching model. Chemical dosing: Based on the oil content and suspended solids concentration of the influent, control the plunger metering pump to add 10L / h of demulsifier, 8L / h of flocculant, and 2L / h of corrosion inhibitor. The atomizing nozzle will evenly spray the chemicals into the reaction zone and stirring area.

[0058] Stirring adjustment: In the initial stage of the reaction, start the rapid mixing mode with a stirring speed of 350 r / min for 5 minutes; then switch to the slow flocculation mode with a stirring speed of 80 r / min for 20 minutes to ensure that the reagent reacts fully with the wastewater to form stable flocs.

[0059] Filtration and backwashing: After sedimentation in the sedimentation zone, the wastewater enters the filtration zone, where the modified fiber ball filter module traps residual suspended solids and oil. When the differential pressure sensor detects a differential pressure exceeding 0.15 MPa, the control unit starts the backwash pump and initiates the backwashing process. The backwashing pressure is 0.6 MPa and lasts for 8 minutes. After the backwashing is completed, the filtration operation is automatically restored.

[0060] Water outlet regulation: The water outlet valve control module adjusts the valve opening based on the data from the water outlet pipeline flow sensor to maintain a water outlet flow rate of 50 m³ / h. The water outlet pipeline sensor monitors the water quality in real time to ensure that the water meets the standards for reinjection.

[0061] 4. Self-cleaning and fault handling: The control unit activates the self-cleaning module every 2 hours to rinse the sensor probe and filter assembly for 5 minutes; if the sensor data error exceeds 5%, it immediately triggers on-demand cleaning. The fault self-diagnosis module monitors the status of each unit in real time. If a drug metering sensor malfunctions, it automatically switches to the backup sensor, generates a fault diagnosis report (prompting sensor circuit checks), triggers audible and visual alarms and SMS notifications, ensuring uninterrupted processing.

[0062] 5. Remote Control: The control unit transmits real-time monitoring data and control commands to the remote monitoring platform through the communication module. The platform enables data visualization and allows maintenance personnel to remotely modify control parameters. Daily reports are automatically generated daily, weekly reports are generated weekly, and monthly reports are generated monthly, providing data support for process optimization.

[0063] III. Verification of Operational Results The device was run continuously for 30 days to verify its treatment effect and operational stability. The results are as follows: Water quality compliance: The oil content in the effluent is stable at 2.5~4.8 mg / L, the suspended solids concentration is stable at 3.2~8.5 mg / L, and the COD is stable at 35~48 mg / L, all of which meet the oilfield reinjection standards, with a compliance rate of 100%.

[0064] Control precision: The dosage of the reagent is controlled with a precision of ±0.3%, the stirring speed is controlled with a precision of ±5 r / min, the closed-loop feedback control response time is ≤3s, and there are no fluctuations in water quality exceeding the standard.

[0065] Operation and maintenance efficiency: The fault self-diagnosis module can quickly locate faults, reducing the average fault handling time by 80%; the self-cleaning module reduces the frequency of sensor cleaning by 60%, extends the service life of filter components to 6 months, and reduces operation and maintenance costs by 40%.

[0066] Environmental adaptability: The device operates stably in environments ranging from -25℃ (winter night) to 45℃ (summer afternoon), with sensor monitoring errors ≤ ±2%, and the explosion-proof and protective design prevents any safety accidents.

[0067] In summary, this device can achieve efficient, intelligent, and safe operation of oilfield wastewater treatment, taking into account treatment effect, operation and maintenance efficiency, and environmental adaptability, and is suitable for various oilfield produced water treatment scenarios.

[0068] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An oilfield sewage treatment real-time monitoring and feedback control device, characterized in that, The application relates to an oilfield sewage treatment system, which comprises the following parts: a monitoring unit for collecting multiple water quality parameters and process operation parameters in real time during oilfield sewage treatment, wherein the water quality parameters at least include oil content, suspended matter concentration, COD, pH value and mineralization degree, and the process operation parameters at least include treatment pool liquid level, reagent adding amount, stirring speed and filter assembly pressure difference; the sensor of the monitoring unit has a wide temperature adaptation capability of -40 DEG C to 60 DEG C, a data acquisition frequency of 1 time / s, a data error of not more than +2%, and a daily timing automatic calibration function; a regulation unit containing reagent adding, stirring regulation, filter regulation and effluent valve control modules, which are respectively used for adding demulsifiers, flocculants and corrosion inhibitors, adjusting stirring parameters, controlling filter assembly start-stop and backwashing, and adjusting effluent flow; a control unit electrically connected with the monitoring unit and the regulation unit, wherein the control unit is internally provided with preset water quality standard threshold values and process parameter matching models, is used for receiving real-time parameter data transmitted by the monitoring unit, comparing real-time water quality parameters with preset threshold values, generating regulation instructions through the process parameter matching models in combination with process operation parameters, and sending the regulation instructions to the regulation unit to realize closed-loop feedback regulation; the sensor shell of the control unit and the monitoring unit and the reagent adding module are all designed in an explosion-proof sealing mode, have an explosion-proof grade of not less than Exd IIB T4 Gb, and have a protection grade of not less than IP65; an auxiliary unit including a sewage inlet pipeline, a treatment pool body, an effluent pipeline and a reagent storage assembly, wherein the sewage inlet pipeline is connected to the input end of the treatment pool body, the effluent pipeline is arranged at the output end of the treatment pool body and is connected with the effluent valve control module in series, the reagent storage assembly is connected with the reagent adding module through a pipeline, the detection probe of the monitoring unit extends into the treatment pool body and the effluent pipeline, and the stirring regulation module and the filter regulation module are respectively installed on the treatment pool body; a polyurethane foam heat insulation layer is arranged outside the treatment pool body, has a thickness of not less than 50 mm, and is sequentially divided into a pretreatment area, a reaction area, a precipitation area and a filtration area; the areas are separated by guide plates with guide holes.

2. The oilfield sewage treatment real-time monitoring and feedback control device according to claim 1, characterized in that: The monitoring unit comprises a multi-parameter water quality sensor group and liquid level sensors, flow sensors, pressure difference sensors and reagent metering sensors; the multi-parameter water quality sensor group comprises an online fluorescence oil content sensor, a potassium dichromate digestion-colorimetric COD sensor and the like; the detection probes of the water quality sensors are all provided with anti-fouling coatings; and the sensors respectively detect corresponding parameters and transmit the parameters to the control unit.

3. The device according to claim 1, characterized in that: The reagent adding module comprises three independent reagent storage tanks, a plunger type metering pump with a metering precision of +0.3% and an adding pipeline; the adding pipeline is provided with an atomizing nozzle at the tail end and extends to the stirring area of the treatment pool; the reagent storage assembly is provided with a leakage prevention tray and a liquid level alarm device; when the liquid level in the tank is more than 10% to 90% of the tank capacity, the alarm is triggered and the adding is paused.

4. The oilfield sewage treatment real-time monitoring and feedback control device according to claim 1, characterized in that: The stirring regulation module comprises a variable frequency motor, a stirring shaft and stirring paddles. The control unit adjusts the stirring speed in the range of 50-500 r / min continuously through a frequency converter, and the stirring speed control precision is ±5 r / min, and the control unit can automatically switch the fast mixing mode and the slow flocculation mode according to the water quality parameter change, the stirring speed of the fast mixing mode is 300-500 r / min, and the stirring speed of the slow flocculation mode is 50-150 r / min.

5. The oilfield wastewater treatment real-time monitoring and feedback control device according to claim 1, characterized in that: The filtration control module comprises a modified fiber ball filter core filtration assembly, a backwashing pump and a backwashing pipeline. The control unit controls the backwashing action according to the pressure difference signal detected by the pressure difference sensor, and when the pressure difference exceeds 0.15 MPa, the backwashing pump is automatically started, the backwashing pressure of the backwashing pump is 0.5-0.8 MPa, the backwashing process is started for 5-10 minutes, and the filtration operation is automatically restored after the backwashing is completed.

6. The oilfield wastewater treatment real-time monitoring and feedback control device according to claim 1, characterized in that: The control unit comprises a main control module, a data storage module, a communication module and an alarm module; the main control module is internally provided with a process parameter matching model constructed based on a PID fuzzy control algorithm, and the process parameter matching model can optimize the control parameters; the storage capacity of the data storage module is not less than 1 TB, and the data storage time is not less than 1 year; the communication module supports 4G / 5G and Ethernet communication, and can transmit data to a remote platform; when the water quality exceeds the standard or the equipment fails, the sound-light alarm module triggers an alarm.

7. The device according to claim 1, characterized in that: The treatment tank body is made of corrosion-resistant stainless steel, the inner wall is provided with an anti-fouling coating, and an emergency discharge pipeline and a pressure safety valve are further provided; when the liquid level in the tank exceeds 95% of the tank capacity or the pressure exceeds 0.3 MPa, the emergency discharge pipeline and the safety valve are automatically opened; The device further comprises an emergency power-off module, which cuts off the power supply in the non-explosion-proof area when the concentration of flammable and explosive gas on site is greater than or equal to 1% VOL.

8. The device according to claim 1, characterized in that: Further comprising a self-cleaning module, the self-cleaning module comprises a high-pressure flushing nozzle, a cleaning pump, a special cleaning liquid storage tank and a waste liquid recovery pipeline; the special cleaning liquid is prepared by mixing citric acid and deionized water at a ratio of 1:10; the self-cleaning module can be started regularly every 2 hours, or started when the sensor data error exceeds 5%; the detection probe is flushed at a pressure of 0.2-0.3 MPa, and the filter assembly is flushed at a pressure of 0.5-0.8 MPa; the waste liquid after flushing is returned to the front end of the treatment tank.

9. The device according to claim 1, characterized in that: The preset water quality standard threshold can be set according to the oilfield sewage reinjection or discharge requirements, and the oil content is less than or equal to 5 mg / L and the suspended solid concentration is less than or equal to 10 mg / L under the reinjection standard, and the oil content is less than or equal to 1 mg / L, the suspended solid concentration is less than or equal to 5 mg / L and the COD is less than or equal to 50 mg / L under the discharge standard. The control unit is internally provided with a temperature compensation module, which can automatically calibrate the monitoring data and control instructions according to the environmental temperature, so as to avoid the influence of temperature and humidity on the operation precision.

10. The oilfield wastewater treatment real-time monitoring and feedback control device according to claim 1, characterized in that: The control unit is internally provided with a fault self-diagnosis module, which automatically switches to a standby operation mode and generates a maintenance prompt when a device fault is detected; the remote monitoring platform can realize centralized management and control of multiple devices, supports real-time data visualization, remote control and fault diagnosis functions, and can generate multi-dimensional process optimization reports.

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