SH/T 0619-1995 Determination of Water Separability of Marine Oils

AI-translated method card — human verification pending. This is not an official translation of the standard. Unclear source values remain unverified; check the original standard and product certificate before use.

Card type: Test method

1. Method number / full name / English name / replacement relationship

• Standard number: SH/T 0619-95
• Chinese name: Determination of Water Separability of Marine Oils
• English name: not provided in the available source
• Replacement relationship: not provided in the available source (only “2004 confirmed” is seen)
• Approval/implementation: approved by China Petrochemical Corporation in 1995-06-15, implemented in 1995-10-01
• Adoption relationship: not equivalent to the emulsion separation part of the second edition appendix B of the British Defence Standard 91-22/, “Method for the determination of the separation of emulsions and the stability of oil additives in the presence of water”

2. Scope of application and non-applicability

• Applicable to: marine low-speed crosshead diesel engine oils and medium-speed trunk piston diesel engine oils.
• Specifies a test method for determining the ability of oil and water to separate in the presence of water.
• Not applicable to: not provided in the available source.

3. Method principle

Add 98mL test sample and 2mL distilled water to a conical centrifuge tube, stir at 18℃±2℃ with a specific stirrer at a speed of 3600r/min±100r/min for 30s, then separate the oil-water mixture for 2h under a relative centrifugal force of 700, and evaluate the water separation ability of the oil by observing the volume of the water layer and emulsion layer after centrifugal separation.

4. Reagents and materials (purity / preparation)

• 3.2.1 Distilled water.
• 3.2.2 Straight-run gasoline: final boiling point < 150℃.
• 3.2.3 Petroleum ether: 60—90℃, analytical reagent.

5. Apparatus and equipment

• 3.1.1 Centrifuge: capable of centrifuging two or more conical centrifuge tubes filled with liquid and having a length of 203mm at one time, with the relative centrifugal force at the tip of the centrifuge tubes controllable within the range of 500—800. Speed calculation formula: n=1335√(rcf/d), where n— speed r/min; rcf— relative centrifugal force; d— distance between the tips of two opposing centrifuge tubes in the rotating state mm.
• 3.1.2 Centrifuge tube: conical, dimensions as shown in Figure 1, calibration tolerances as shown in Table 1 (contents of Table 1 not provided in the available source).
• 3.1.3 Stirring device: as shown in Figure 2, motor speed 3600r/min±100r/min, can reach the required speed within 5s after startup, equipped with a timing device and speed display; the stirring paddle is made of 1Cr18Ni9Ti alloy, shape and dimensions as shown in Figure 3.
• 3.1.4 Oven: capable of maintaining a constant temperature at 105℃±2℃.
• 3.1.5 Pipette: 2mL.
• 3.1.6 Stopwatch: minimum scale of 0.1s.
• 3.1.7 Water bath: capable of maintaining a constant temperature at 18℃±2℃.
• 3.1.8 Safety shield: transparent, thickness not less than 6mm, size sufficient to protect the operator.

6. Recommended operating conditions

• Water bath/fixed cylinder temperature: 18℃±2℃.
• Stirring speed: 3600r/min±100r/min, reached within 5s.
• Stirring time: 30s.
• Distance from the tip of the stirring paddle to the bottom of the centrifuge tube: 3mm±0.5mm.
• Centrifugal relative centrifugal force: 700 (at the bottom of the centrifuge tube).
• Centrifugation time: 2h.
• Oven temperature: 105℃±2℃.

7. Sampling and sample preparation

• 4.1 Cleaning of the centrifuge tube: thoroughly clean the centrifuge tube with straight-run gasoline, petroleum ether, tap water and distilled water in sequence, then place it in an oven to dry for 1h, take out the centrifuge tube with a clamp, allow it to cool naturally to room temperature, and set aside for use.
• 4.2 Cleaning of the stirring paddle: immerse the stirring paddle vertically in petroleum ether 2—3 times, then rinse repeatedly with petroleum ether from a wash bottle, and set aside for use after the petroleum ether has completely evaporated.
• 4.3 Setting of stirring time: start the motor, and immediately start timing when the speed reaches 3600r/min±100r/min; the set time is 30s plus the time to reach that speed.
• 5.3 Add about 50mL of test sample to the centrifuge tube, add 2mL of distilled water with a pipette, then add test sample to the 100mL mark.

8. Analytical procedure

• 5.1 Place the centrifuge tube in the fixed cylinder of the stirring device, then place the fixed cylinder in the magnetic stop groove of the stirring device base, then insert the stirring paddle into the drill chuck and secure it, adjust the height of the stirring paddle with the handwheel so that the tip of the stirring paddle is 3mm±0.5mm from the bottom of the centrifuge tube. Then fix the positioning ring to ensure that each time the telescopic cylinder descends to the lowest point, the distance from the tip of the stirring paddle to the bottom of the centrifuge tube is 3mm±0.5mm.
• 5.2 Connect the water bath to the fixed cylinder, and maintain the temperature inside the fixed cylinder at 18℃±2℃.
• 5.3 Take out the centrifuge tube, add about 50mL of test sample, add 2mL of distilled water with a pipette, then add test sample to the 100mL mark.
• 5.4 Place the centrifuge tube containing the test sample in the fixed cylinder, place the fixed cylinder in the magnetic stop groove of the stirring device base, and set it securely.
• 5.5 Lower the stirring paddle; at this time the stirring paddle should be located at the center of the centrifuge tube, and the stirring paddle and the centrifuge tube should be concentric. Turn the stirring paddle by hand; there must be no friction between any part of the stirring paddle and the centrifuge tube. Place the safety shield in an appropriate position. Leave the centrifuge tube for a period of time so that the test sample in the centrifuge tube reaches the same temperature as the water bath.
• 5.6 Start the motor; within 5s the speed of the stirrer should reach 3600r/min±100r/min, and stir at this speed for 30s.
• 5.7 Stop stirring, shake the handwheel, lift the stirring paddle from the centrifuge tube, and suspend it for 2min so that the test sample remaining on the paddle drips into the centrifuge tube.
• 5.8 Clean the residual oil on the stirring paddle with petroleum ether and carefully wipe it with silk cloth until it is confirmed clean, then air-dry.
• 5.9 Within 15min, place the centrifuge tube (clause 5.7) into the centrifuge and start the centrifuge. The relative centrifugal force at the bottom of the centrifuge tube is 700, and the operating time is 2h.
• 5.10 Take the centrifuge tube out of the centrifuge and evaluate the test results.

9. Qualitative and quantitative determination and calculation formulas

• 6.1 Water layer volume: read to 0.05mL.
• 6.2 Emulsion layer volume: above 2mL read to 0.1mL; below 2mL read to 0.05mL.
• 6.3 For submission for product quality certification, take a color photograph of the lower end of the centrifuge tube within 30min after completing the test.
• Test result report: a. volume of separated water layer, mL; b. volume of separated emulsion layer, mL. Take the arithmetic mean of two results from duplicate determinations as the test result report (mL, retain two decimal places).
• Centrifuge speed calculation formula: n=1335√(rcf/d) (see Section 5).

10. Precision

not provided in the available source.

11. Report

The test results shall report the following items:

• a. Volume of separated water layer, mL.
• b. Volume of separated emulsion layer, mL.
• Take the arithmetic mean of two results from duplicate determinations as the test result report (mL, retain two decimal places).

12. Referenced documents

not provided in the available source (the main text does not list a normative reference document list).

13. Source and verification

This page is an AI translation of the available Chinese method card. Human verification is pending. It is not an official translation of the standard. Check the source standard and product certificate before use.

14. Quick reference Q&A