Application of automatic density meter Digipol-D70 in detecting API degree of crude oil and refined

In the petroleum industry, crude oil API degree and oil product density testing are of great significance for crude oil classification, quality assessment and trade settlement. The fully automatic density meter Digipol-D70 from Shanghai Welding Instrumentation Co., Ltd. plays a key role in the relevant inspection with its excellent performance.

I. Overview of crude oil API degree and refined oil testing
(A) crude oil API degree related concepts
API degree is developed by the American Petroleum Institute, used to measure the density of oil and products, is one of the main international crude oil pricing standards. Its value is negatively correlated with the crude oil density, and the larger the value, the lighter the crude oil and the higher the price. Our country divides crude oil into light, medium, heavy and extra heavy crude oil according to API degree. In crude oil trade, the accurate detection of API degree is very important to determine the value of crude oil and ensure the fairness of trade.

(2) Significance of oil density detection
The density of refined oil such as gasoline and diesel at a specific temperature (usually 20 ° C) is an important indicator to measure its quality. Density affects the combustion performance, storage stability and energy content of refined oil products, and must be accurately measured when trading to ensure product quality and trade justice.

Second, Digipol-D70 automatic density meter performance advantages
(1) Measurement principle and accuracy

Digipol-D70 uses the advanced U-shaped vibration tube method to determine the sample density by detecting the vibration frequency. With a density measurement range of 0.00000-3.00000 g/cm³, the measurement accuracy can reach ±0.0003g/cm³, the resolution is ±0.00001g/cm³, and the repeatability is ±0.0001g/cm³, which can meet the requirements of high-precision detection of crude oil and refined oil.

(2) Functional characteristics
Convenient operation: The instrument is equipped with intuitive operation interface, such as large color LCD touch screen, easy to understand operation, reducing the skill threshold of the operator and reducing human error. When testing, one-click operation can start the measurement, convenient and fast.
Rapid measurement: After the temperature balance, the measurement time of a single sample is only about 1 minute, which greatly improves the detection efficiency, and is suitable for high-frequency and large-scale detection tasks, meeting the efficient detection needs of the oil industry.
Multi-parameter measurement: In addition to directly measuring API degree, it can also measure a variety of parameters, such as density, specific gravity, etc. Through the internal data processing system, the complex conversion can be automatically completed without manual table lookup, improving the detection efficiency and accuracy.
Data processing and storage: with powerful data processing functions, measurement results can be displayed, saved and exported in real time. Support a variety of data formats output, such as PDF, Excel, convenient data management and analysis. The built-in large-capacity memory can store at least 1000 sets of data for easy data tracing and historical query.
(3) Environmental adaptability and stability

Temperature control system: with high precision temperature control device, temperature control range of 15-40 ℃, temperature control accuracy of ±0.05℃, temperature control accuracy of ±0.2℃. It can accurately control the measurement temperature, effectively reduce the influence of temperature on the density measurement of crude oil and refined oil, and ensure the measurement results are stable and reliable.
Anti-interference design: The design of the instrument fully considers the interference factors of the industrial environment, the use of special shielding technology and stable circuit system, to reduce the interference of external factors on the measurement, to ensure that the normal work in a complex environment, the measurement results are not affected.
Third, the application of Digipol-D70 in crude oil API degree detection
(1) Testing process
Instrument preparation: preheat the machine to make the internal temperature of the instrument stable. Calibrate the instrument using dry air and distilled water to ensure measurement accuracy. If the measured value is out of tolerance, it needs to be recalibrated to ensure the measuring accuracy of the instrument.
Sample treatment: Take an appropriate amount of crude oil sample with a clean syringe, slowly inject the U-shaped vibration tube, the injection amount is 2-3ml, and carefully check the tube for bubbles. If there are bubbles, the sample should be re-injected to avoid bubbles affecting the measurement results.
Measurement operation: Set the instrument temperature to 15.6℃, after the sample temperature and instrument temperature balance, select API degree measurement mode to start measurement. The instrument automatically collects data and calculates, and displays the measurement results.
Data recording and processing: After the measurement is completed, record the API degree measurement value, which can average the multiple measurement data and improve the measurement accuracy. Data can be stored inside the instrument or exported via a USB interface or USB flash drive for subsequent analysis and report generation.
Instrument cleaning: After the test is completed, clean the U-shaped vibration tube with petroleum ether or kerosene to remove residual samples. Then clean with anhydrous alcohol, and finally dry with dry air to prevent the sample residual contamination of the detection element, affecting the accuracy of the next measurement.
(2) Application cases
An oil trading company used Digipol-D70 to test the API degree of different batches of crude oil in the crude oil procurement process. Through accurate measurement, the type of crude oil can be accurately judged to provide a basis for purchase pricing. In one purchase, a batch of cargo claiming to be light crude oil was tested and measured by Digipol-D70, its API level did not meet the light crude oil standard, avoiding the loss of the company's purchase of low-quality crude oil at a high price.

Fourth, the application of Digipol-D70 in the detection of refined oil
(1) Testing process
Instrument preparation and calibration: Similar to crude oil testing, after starting up and preheating, calibrate the instrument with dry air and distilled water to ensure measurement accuracy.
Sample preparation: The product oil sample is placed in a constant temperature environment of 20℃ to make its temperature stable. Take an appropriate amount of sample with a clean syringe and slowly inject it into the U-shaped vibration tube to check for bubbles.
Measurement and data processing: Select the density measurement mode to measure and record the density of the finished oil at 20 ° C. Multiple measurements are averaged to ensure accurate measurement results. Data can be stored and exported for quality assessment and trade settlement.
Instrument cleaning and maintenance: After the completion of the test, clean the instrument according to the regulations, regular maintenance, to ensure the stability of the instrument performance.
(2) Application cases
A refinery used Digipol-D70 to monitor product density in real time during the production of refined oil products. In the diesel production line, through continuous testing, a batch of diesel density anomalies are found in time, and the production process is adjusted to ensure product quality and avoid unqualified products from entering the market.

5. Application precautions
(1) Control of environmental factors
Keep the measurement environment temperature stable to avoid temperature fluctuations affecting the measurement results. The measuring environment should be clean and dry to reduce the erosion of dust and moisture on the instrument.

(2) Sample handling points
Ensure uniform sample to avoid delamination or impurities affecting measurement accuracy. Prevent air bubbles from mixing in the sample. If air bubbles are found, re-process the sample.

(3) Instrument maintenance
Calibrate the instrument regularly to ensure measurement accuracy. Clean and maintain the instrument according to the instructions, and replace the wearing parts in time to ensure the long-term stable operation of the instrument.