GB/T 1793-2008 Aviation Fuel Water Reaction Test Method

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Card type: Test method

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

• Standard number: GB/T 1793—2008
• Chinese name: Aviation Fuel Water Reaction Test Method
• English name: Standard test method for water reaction of aviation fuels
• Replacement relationship: replaces GB/T 1793—2000; GB/T 1793—2000 was formulated by equivalent adoption of ASTM D1094—97. Previous versions: GB/T 1793—1979, GB/T 1793—2000.
• Adoption relationship: modified adoption of ASTM D1094-00 (2005) "Standard Test Method for Water Reaction of Aviation Fuels", redrafted according to ASTM D1094-00 (2005).
• Main differences from ASTM D1094-00 (2005): the referenced standards of this standard adopt the corresponding national standards and industry standards of our country.
• Editorial modifications: deleted the keywords of Chapter 13; in accordance with the drafting format of our country's standards, textual modifications were made to ASTM D1094-00 (2005).
• Main changes compared with GB/T 1793—2000: in Chapter 2, added referenced standard SH/T 0616; in the terms and definitions of Chapter 3, added terms such as film, ribbon, foam, and debris; the water reaction interface rating was changed from the original three levels 1, 1b, 2 to the five levels 1, 1b, 2, 3, 4 of this standard.
• Publication/implementation: published on 2008-02-13, implemented on 2008-09-01.
• Proposal/administration/drafting: proposed by China Petrochemical Corporation; administered by the Petrochemical Research Institute of China Petroleum & Chemical Corporation; drafting organization is the Petrochemical Research Institute of China Petroleum & Chemical Corporation; main drafters: Gong Dongmei, Zhang Cuijun.

2. Scope of application and non-applicability

• Scope of application: specifies the inspection of water-soluble components in aviation gasoline and aviation turbine fuels and the determination method for the effects of these components on volume change and the oil-water interface.
• System of units: adopts International System of Units [SI] units.
• Safety note: use may involve hazardous materials, operations, and equipment; this standard does not purport to address all safety problems associated with this; users are responsible for establishing appropriate safety and protection measures before using this standard and for clarifying its restricted scope of application.
• Non-applicability: the source text does not explicitly list a non-applicable scope.

3. Method principle

The sample placed in a clean glass graduated cylinder is shaken uniformly with phosphate buffer solution at room temperature using a standard method. The cleanliness of the glass graduated cylinder is checked, and the change in the volume of the aqueous layer and interface phenomena are used as the water reaction test results of the sample. (Chapter 4 Method summary)

4. Reagents and materials (purity / preparation)

• 4.1 Reagent purity: analytical grade reagents shall be used in all tests. (source text 7.1)
• 4.2 Water purity: distilled water or water of equivalent purity. (source text 7.2)
• 4.3 Acetone. Warning: flammable, harmful to health. (source text 7.3)
• 4.4 Glassware cleaning solution: a mixed solution of saturated concentrated sulfuric acid (H₂SO₄, relative density 1.84) with potassium dichromate (K₂Cr₂O₇) or sodium dichromate (Na₂Cr₂O₇). Warning: corrosive, harmful to health, oxidizer. (source text 7.4)
• 4.5 Industrial hexane: meets the requirements of GB/T 17602. Warning: flammable, harmful to health. (source text 7.5)
• 4.6 n-Heptane: meets the requirements of GB/T 11117.2. Warning: flammable, harmful to health. (source text 7.6)
• 4.7 Petroleum ether: 60 ℃～90 ℃, meets the requirements of GB/T 15894. Warning: flammable, harmful to health. (source text 7.7)
• 4.8 Phosphate buffer solution (pH=7): dissolve 1.15 g anhydrous dipotassium hydrogen phosphate (K₂HPO₄) and 0.47 g anhydrous potassium dihydrogen phosphate (KH₂PO₄) in 100 mL water. If a larger amount of phosphate buffer solution is to be prepared, the concentrations of the two phosphates in the aqueous solution shall be kept the same as described above. Likewise, laboratories may also use commercial buffer solutions. (source text 7.8)
• Note: in the referenced documents of Chapter 2 of the source text, GB/T 1589D chemical reagent petroleum ether, GB 17602 CD industrial hexane have source-text extraction noise, requires confirmation against the source standard (source-text extraction); the main text 7.5, 7.7 are respectively written as GB/T 17602, GB/T 15894.

5. Instruments and equipment

• Glass graduated cylinder: with a glass stopper, 100 mL, scale division 1 mL, the distance between the 100 mL mark and the top of the graduated cylinder shall be 50 mm～60 mm. (Chapter 6 of the source text)
• Other instruments and equipment: not provided in the available source.

6. Recommended operating conditions

• Test temperature: room temperature (source text 10.1).
• Shaking conditions: shake the graduated cylinder up and down 2 min±5 s, 2～3 times per second, with a shaking amplitude of 12 cm～25 cm. (source text 10.2)
• Standing conditions: immediately place the graduated cylinder on a platform free of vibration and let stand for 5 min. (source text 10.3)
• Observation conditions: do not pick up the graduated cylinder; observe and record under scattered light. (source text 10.4)
• Caution: shake the graduated cylinder carefully to avoid creating a vortex, because it will destroy any emulsion that may form. (source text 10.2 Caution)

7. Sampling and sample preparation

• The sample shall be at least 100 mL. A clean container is required. (source text 9.1)
• Under no circumstances shall the sample taken be pre-filtered. The filter medium may remove surfactants, and the detection of surfactants is one of the purposes of this test method. If the sample is contaminated by particulate matter, settling may be carried out before testing. (source text 9.2)
• Note: test results are easily affected by trace contaminants in the sampling container. (source text 9.2 Note)
• Instrument preparation (cleaning of graduated cylinder):
  • 8.1 The graduated cylinder shall be thoroughly cleaned before testing.
  • 8.1.1 Rinse the graduated cylinder and stopper with hot tap water to remove oil traces, and brush if necessary. Alternatively, remove all oil traces from the graduated cylinder and stopper with industrial hexane, n-heptane, or petroleum ether. Then rinse with tap water, and finally rinse with acetone.
  • 8.1.2 After cleaning according to the procedure described in 8.1.1, immerse the graduated cylinder and stopper in a nonionic detergent solution or the glassware cleaning solution specified in 7.4. Each laboratory needs to determine the type of nonionic surfactant and establish the conditions for its use, so as to achieve a cleaning effect equivalent to that of chromic acid cleaning solution. The use of nonionic surfactants can avoid some potential hazards and the trouble of handling corrosive chromic acid cleaning solution. The latter is still retained in the reference cleaning procedure as another option to the preferred nonionic detergent solution cleaning procedure. After cleaning with the nonionic detergent solution or glass cleaning solution, rinse respectively with tap water and distilled water, finally rinse with phosphate buffer solution and dry.
  • 8.1.3 If the glass graduated cylinder is not cleaned thoroughly enough, the test may give a false indication that the fuel is contaminated. Only a completely clean graduated cylinder may be used. Invert the cleaned graduated cylinder; only a graduated cylinder from which the cleaning liquid is completely drained (with no droplets adhering to the wall) is completely clean. In addition, a separation degree rating (see Table 1) equal to or less than grade 2 indicates that the glass graduated cylinder is completely clean.

8. Analytical procedure

• 10.1 At room temperature, take 20 mL phosphate buffer solution and pour it into the graduated cylinder, record the volume to the nearest 0.5 mL. At room temperature, add 80 mL sample and stopper with a glass stopper.
• 10.2 Shake the graduated cylinder up and down 2 min±5 s, 2～3 times per second, with a shaking amplitude of 12 cm～25 cm. Caution: shake the graduated cylinder carefully to avoid creating a vortex, because it will destroy any emulsion that may form.
• 10.3 Immediately place the graduated cylinder on a platform free of vibration and let stand for 5 min.
• 10.4 Do not pick up the graduated cylinder; under scattered light, observe and record the following:
  • 10.4.1 The change in the volume of the aqueous phase, to the nearest 0.5 mL.
  • 10.4.2 Rate according to Table 2.
  • 10.4.3 Determine the degree of separation of the two phases according to Table 1.
  • 10.4.4 Slight turbidity appearing in the fuel layer may be disregarded if this turbidity is not observable against a white background.

9. Qualitative and quantitative determination and calculation formulas

• Change in aqueous phase volume: record the change in the volume of the aqueous phase, to the nearest 0.5 mL (source text 10.4.1, 11.1.1).
• Interface condition rating (Table 2):
  • Grade 1: clear and clean
  • Grade 1b: small clear bubbles covering an interface estimated to be no greater than 50%, with no debris, ribbon, or film at the interface
  • Grade 2: debris, ribbon, or film at the interface
  • Grade 3: loose ribbons and/or a small amount of foam
  • Grade 4: tight ribbons and/or more foam
• Separation degree rating (Table 1):
  • Grade 1: completely no emulsion and/or precipitate in each layer or on the fuel layer
  • Grade 2: same as grade 1 except for small bubbles or small water droplets in the fuel layer
  • Grade 3: emulsion and/or precipitate in each layer or on the fuel layer, or small droplets in the aqueous layer, or small droplets adhering to the wall of the graduated cylinder (excluding the wall surface above the fuel layer)
• Calculation formula: not provided in the available source.

10. Precision

• 12.1 Precision: the change in the volume of the aqueous phase is a qualitative indication of the water reaction of aviation gasoline and water-soluble components, so no precision is reported.
• 12.1.1 Because the aviation turbine fuel water reaction rating method is entirely qualitative, it is impractical to specify precision for the water reaction interface rating; a number is assigned to the interface ratings in Table 2 to facilitate qualitative rating.
• 12.2 Bias: Because the volume change value and interface rating are defined only according to this test method, the test procedure has no bias.

11. Report

• 11.1 This report shall include the following:
  • 11.1.1 Water phase volume change, accurate to 0.5 mL.
  • 11.1.2 Interface condition rating (see Table 2).
  • 11.1.3 Separation degree rating (see Table 1).

12. Referenced Documents

• GB/T 11117.2 Knock test reference fuels—reference fuel n-heptane
• GB/T 1589D Chemical reagent petroleum ether (requires confirmation against the source standard (source-text extraction), in the main text 7.7 written as GB/T 15894)
• GB 17602 CD industrial hexane (requires confirmation against the source standard (source-text extraction), in the main text 7.5 written as GB/T 17602)
• SH/T 0616 Jet fuel water separation index determination method (portable separator method)
• Note: In the referenced documents of Chapter 2 of the original text, some standard numbers contain source-text extraction noise, requires confirmation against the source standard (source-text extraction).

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