Interfacial Tension Test of Petroleum Products

Interfacial Tension Test of Petroleum Products

Overview

  Petroleum products are a general term for various oil products processed from crude oil through distillation, refining and other processes, including lubricating oil, fuel oil, transformer oil and other categories, which are widely used in industrial production, transportation, power transmission and other fields. Interfacial tension is an important physicochemical index of petroleum products, which characterizes the interfacial molecular force between oil and media such as water when they are in contact. Its value directly reflects the emulsification performance, anti-foaming property and compatibility with other media of petroleum products, and has a key impact on the storage, transportation and application performance of petroleum products.

Test Purpose

  By detecting the interfacial tension value of petroleum products, we can determine the purity of the oil, the effectiveness of additives and the performance degradation during service, which provides an important basis for the quality control and working condition applicability evaluation of petroleum products. This test is carried out in accordance with GB 6541-86 Standard Test Method for Interfacial Tension of Oil Against Water by the Ring Method for Petroleum Products. The SH107 Automatic Interfacial Tensiometer is a fully automatic testing equipment specially designed for this standard, which can accurately complete the determination of interfacial tension between petroleum products and water, as well as the surface tension of liquids.

Test Samples and Instruments

Test sample: Petroleum product to be tested (such as transformer oil, lubricating oil, etc.)

Test instruments and materials:

• SH107 Automatic Interfacial Tensiometer
• Cleaning reagents including petroleum distilled water, anhydrous ethanol, etc.
• Auxiliary tools such as alcohol lamp

Operation Procedures

• Thoroughly clean and dry the platinum ring and sample cup of the instrument. Install the cleaned platinum ring on the ring support rod of the instrument, adjust the machine feet to center the level bubble on the sample tray, connect the power supply, turn on the instrument and preheat it.
• Click the color touch screen of the instrument to enter the parameter setting interface, check and confirm the parameters including platinum wire radius, platinum ring radius, density of heavy liquid (water) and density of light liquid (petroleum product), save the settings and return to the main menu.
• Perform pure water calibration: pour distilled water into a clean sample cup up to the scale line, place the sample cup in the center of the sample tray, click "Pure Water Calibration", adjust the platform height through the ascend/descend buttons, and start the test until the calibration result is within the qualified range of 71~72 mN/m.
• After the calibration is completed, enter the sample test interface. The instrument will automatically immerse the platinum ring into the distilled water in the sample cup to the designated position. When prompted, slowly pour the petroleum product to be tested up to the scale line, and click "Continue".
• The instrument will start the tension test after an automatic delay, and display the dynamic tension curve in real time. After the test, it will automatically calculate and display the interfacial tension result of the petroleum product, store the data in the historical record at the same time, and can directly print the test result.
• If multiple groups of samples need to be tested, repeat the above sample test steps without shutting down the instrument.

Data Analysis and Result Evaluation

  For qualified industrial transformer oil tested by the SH107 Automatic Interfacial Tensiometer, its interfacial tension against water at 25℃ is usually ≥35 mN/m, and the results obtained in this test are all within this reasonable range. The instrument has a repeatability error of ≤0.3% and an accuracy of 0.1 mN/m, with accurate and stable test data, which fully meets the quality inspection requirements for the interfacial tension of petroleum products.

The fully automatic operation mode of the instrument greatly reduces manual operation errors. The color touch screen and Chinese character menu make the operation process simpler. The historical data storage and printing functions also provide convenience for the sorting of test reports and data traceability. It is suitable for daily inspection work in petrochemical enterprises, quality inspection institutions and other scenarios.