The oil-water stratification instrument can significantly optimize the water injection control of the electric desalination device by real-time monitoring of the oil-water boundary and water content, combined with intelligent algorithms and closed-loop control. The specific optimization path is as follows:
1. Accurate boundary detection: dynamically adjust the water injection baseline
The electric desalination device needs to dilute the salt in the crude oil by injecting water. Insufficient water injection will lead to a decrease in desalination rate, while excessive water injection will increase energy consumption and subsequent processing load. The oil-water stratification instrument adopts microwave energy absorption technology (such as the ID200 series boundary detector), which utilizes the difference in dielectric constants (order of magnitude) between oil and water to detect the absorption rate of spherical media through high-frequency and low-power microwave detection
The aqueous phase absorbs most of the signal and outputs a strong analog signal (4-20mA current corresponds to a moisture content of 0-100%);
Oil phase absorbs weak signals and outputs weak analog signals.
The system dynamically calculates the required water injection volume based on the real-time detection of the oil-water boundary height. For example, when the oil-water boundary is detected to be too low (the water layer is too thin), the frequency of the water injection pump is automatically increased, and the water injection volume is increased to 110% of the theoretical calculation value to ensure that the salt is fully dissolved; When the boundary is too high, reduce the water injection rate to 90% to avoid excessive dilution.
2. Real time feedback on moisture content: closed-loop correction of water injection deviation
The oil-water stratification instrument is equipped with a water content analyzer (such as the 0W300 series), which uses a composite high-frequency microwave method to measure the fluid dielectric properties. It is not affected by salinity, density, or viscosity and can output real-time crude oil water content data. The system compares the detected value with the preset target moisture content (such as 0.3%):
If the actual moisture content is greater than the target value, it indicates that there is too much water injection. The system reduces the opening of the water injection pump and lowers the instantaneous flow rate through PID algorithm;
If the actual moisture content is less than the target value, increase the opening and increase the water injection volume.
A certain refinery application case shows that closed-loop control reduces the fluctuation range of water injection from ± 15% to ± 3%, and the salt content of desalinated crude oil decreases from 15mg/L to 3mg/L, saving an annual energy consumption of 2 million yuan.
3. Multi parameter collaborative control: adapting to dynamic changes in working conditions
The oil-water stratification instrument can integrate temperature and pressure sensors, combined with crude oil flow rate data (measured by an external clamp ultrasonic flowmeter), to construct a multi parameter control model:
Temperature compensation: When the temperature of crude oil increases (such as from 50 ℃ to 80 ℃), the water density decreases, and the boundary detector needs to adjust the microwave absorption threshold according to the temperature to avoid misjudgment;
Pressure synergy: Under a high-voltage electric field (such as 15kV/cm), the coalescence speed of water droplets accelerates. The system dynamically adjusts the water injection interval based on pressure sensor data (such as changing from every 10 minutes to every 5 minutes) to enhance the dehydration effect.
4. Anti interference design and redundancy verification: ensuring long-term stable operation
In response to interference from the emulsion layer, the oil-water stratification instrument adopts a three electrode redundant design:
When three pairs of electrodes work simultaneously and the detection results of two pairs of electrodes are consistent, the system adopts the data; If there is a contradiction (such as one pair of electrodes displaying oil layer and two pairs displaying water layer), an alarm will be triggered and switched to manual control mode;
Self cleaning function: The electrode surface is coated with an oil repellent coating, combined with regular pulse blowback (0.5MPa compressed air), to prevent wax deposition and conductivity degradation.