SH/T 0568-1993 Determination of Storage Stability of Water-in-Oil Emulsions (Oven Method)

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Card type: Test method

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

• Standard number: SH/T 0568-93
• Full title: Determination of Storage Stability of Water-in-Oil Emulsions (Oven Method)
• English name: not provided in the available source
• Replacement relationship: not provided in the available source
• Other: confirmed in 2004; reference adoption of ASTM D3707-89 "Determination of Storage Stability of Water-in-Oil Emulsions (Oven Method)"
• Approval/implementation: approved by China Petrochemical Corporation 1993-08-19, implemented on 1994-05-01

2. Scope of application and non-applicability

• This standard specifies a method for determining the storage stability of water-in-oil emulsions.
• This standard applies to water-in-oil emulsions.
• Not applicable: not provided in the available source.

3. Method principle

Take a 100 mL test sample, place it in an oven at 85℃±1℃, and keep it at constant temperature for 48 h or 96 h. Then determine its oil separation amount [%(V/V)], water separation amount [%(V/V)], and the water content [%(m/m)] in the upper and lower test samples at the specified positions.

4. Reagents and materials (purity / preparation)

not provided in the available source.

5. Instruments and equipment

• 5.1 Oven: with forced air circulation, temperature controlled at 85℃±1℃.
• 5.2 Graduated cylinder: 100 mL, with graduations of 1 mL, with a ground-glass stopper. The stopper shall have a vent groove.
• 5.3 Pipette: 10 mL.
• 5.4 Microsyringe: 0.5 or 1 μL.
• 5.5 Narrow-mouth glass bottle: about 30 mL.
• 5.6 Rubber bulb.

6. Recommended operating conditions

• Oven temperature: 85℃±1℃.
• Constant-temperature time: 48 h or 96 h.
• Placement position of the graduated cylinder: place in the middle of the oven and at least 75 mm from the bottom of the oven to ensure uniform heating.
• Standing at room temperature after the test: stand at room temperature (21℃±3℃) for 1 h.
• Sampling positions: the upper test sample is taken at the 80 mL mark of the graduated cylinder; the lower test sample is taken at the 15 mL mark of the graduated cylinder.

7. Sampling and test sample preparation

• Place the sample into a container of 1 L or 500 mL, and shake vigorously by hand or mix mechanically for 3～5 min to ensure the sample is uniform.
• Note: A water-in-oil emulsion is a two-phase system, unlike a completely homogeneous system; therefore, it is difficult to mix in a large container and to withdraw a representative test sample. The best method for obtaining a uniform liquid is continuous, vigorous mechanical stirring. However, for unstable emulsions that have been stored for more than half a year, this sampling method also cannot obtain a representative test sample.

8. Analytical procedure

• 7.1 Measure 100 mL of test sample with a graduated cylinder, and cover it.
• 7.2 Place the graduated cylinder in an oven maintained at 85℃±1℃, and leave it for 48 h (or 96 h). When placing it, the graduated cylinder shall be placed in the middle of the oven and at least 75 mm from the bottom of the oven to ensure uniform heating.
  • Note: When completing multiple tests within the same time period, adjust the positions of the graduated cylinders to avoid temperature changes in the oven caused by inappropriate convection. For the same reason, the number of tests completed at the same time should be limited.
• 7.3 After 48 h (or 96 h), remove the graduated cylinder from the oven and leave it at room temperature (21℃±3℃) for 1 h.
• 7.4 Observation and recording:
  • 7.4.1 Oil separation amount [%(V/V)].
  • 7.4.2 Water separation amount [%(V/V)].
• 7.5 Using a 10 mL pipette, withdraw the test sample according to the following steps:
  • 7.5.1 Place the tip of the pipette accurately at the 80 mL mark of the graduated cylinder, slowly draw 10 mL of test sample, and transfer it to a narrow-mouth glass bottle of about 30 mL. The sample thus obtained is the upper test sample.
  • 7.5.2 Place the tip of the pipette accurately at the 15 mL mark of the graduated cylinder, slowly draw 10 mL of test sample, and transfer it to a narrow-mouth glass bottle of about 30 mL. The sample thus obtained is the lower test sample.
  • Note: If the water separation amount is equal to or exceeds 10%(V/V), then the determination of the lower-layer water content may be omitted.
• 7.6 Shake the narrow-mouth glass bottle of about 30 mL containing the test sample, take 0.5 μL of test sample with a microsyringe, and determine the water content [%(m/m)] of the upper and lower test samples in accordance with SH/T 0246.

9. Qualitative and quantitative determination and calculation formulas

• Determination items: oil separation amount [%(V/V)], water separation amount [%(V/V)], upper-layer water content [%(m/m)], lower-layer water content [%(m/m)].
• The determination of water content shall be carried out in accordance with SH/T 0246.
• Calculation formulas: not provided in the available source.

10. Precision

The precision of this standard depends on the degree of stability of the emulsion.

9.1 Type I — Stable emulsion

Note: A test sample whose water separation amount does not exceed 1%(V/V) after testing at 85℃ for 48 h or 96 h, and whose upper and lower layer water contents differ relatively little, with a ratio greater than 0.9.

Judge the reliability of the test results according to the following provisions (95% confidence level):

• 9.1.1 Repeatability: The difference between two results obtained by the same operator from repeated determinations shall not be greater than the value specified for repeatability in Table 1.
• 9.1.2 Reproducibility: The difference between two results submitted by different laboratories shall not be greater than the value specified for reproducibility in Table 1.

Table 1 Precision of Type I

Note: The above precision provisions were obtained from hydraulic fluids with water contents between 35%～50%(m/m) through statistical testing of interlaboratory test results.

9.2 Type II — Unstable emulsion

Note: A test sample whose water separation amount exceeds 10%(V/V) after testing at 85℃ for 48 h or 96 h. The precision limits of the 96 h test are the same as those in Table 1.

9.3 Type III — Marginal-stability emulsion

The change in the stability of the test sample varies with the treatment time or conditions or both, making the determination precision meaningless; therefore, no precision is specified. Note: A test sample whose water separation amount does not exceed 10%(V/V) after testing at 85℃ for 48 h or 96 h, but whose upper and lower layer water contents differ relatively greatly, with a ratio less than 0.9.

11. Report

• 8.1 Oil separation amount [%(V/V)].
• 8.2 Water separation amount [%(V/V)].
• 8.3 Upper-layer water content [%(m/m)].
• 8.4 Lower-layer water content [%(m/m)].

12. Referenced documents

• SH/T 0246 Determination of Water Content in Light Petroleum Products (Coulometric Method)

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 Q&A reference