GB/T 11129-1989 Determination of Water Separation Index of Jet Fuels

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Card type: Test method

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

• Standard number: GB 11129-89
• Chinese name: Determination of Water Separation Index of Jet Fuels
• English name: Jet fuels - Determination of water separation characteristics
• Replacement relationship: From the date of implementation of this standard, the former Ministry of Petroleum Industry standard SY 2233-80 "Determination of Water Separation Index of Jet Fuels" is void.
• Reference adoption: American Society for Testing and Materials standard ASTM D2550-85 "Determination of Water Separation Index of Jet Fuels".
• Approval/implementation: Approved by China Petrochemical Corporation 1989-03-31, implemented on 1990-04-01.

2. Scope of application and non-applicability

• This standard specifies a method for determining the water separation characteristics of jet fuels.
• It is applicable to evaluating the cleanliness of jet fuels, can reflect whether surfactants such as sulfonates and naphthenates are present in the fuel, and estimates the ability of the fuel to separate water when passing through a filter coalescer.
• Not applicable: not provided in the available source.

3. Method principle

In a water separation index tester, after water and fuel form an emulsion, it quantitatively passes through a coalescer cell equipped with a standard filter pad, and the turbidity of the fuel after passing through the coalescer is measured by a photocell.

4. Reagents and materials (purity / preparation)

• 5.1 Isopropanol: chemically pure.
• 5.2 Acetone: chemically pure (the extracted reagent name is garbled; requires confirmation against the source standard (source-text extraction)).
• 5.3 Toluene: analytically pure.
• 5.4 Benzene: analytically pure.
• 5.5 Chloroform: chemically pure.
• 5.6 Dispersant: each milliliter of toluene contains 1 mg anhydrous sodium di(2-ethylhexyl) sulfosuccinate (100% dried, abbreviated as penetrant T).
  • 5.6.1 If 100% dried penetrant T is not available, purification method: take 100 g water-containing penetrant T, distill off water at atmospheric pressure, obtaining about 50 g anhydrous penetrant T; dissolve in 700–800 g benzene, let stand for 6–7 days, remove precipitate; first distill off benzene at atmospheric pressure, then distill to dryness under a water aspirator, obtaining light yellow anhydrous penetrant T, store in a desiccator for later use.
• 5.7 Distilled water.
• 5.8 Reference liquids: liquids prepared with reference base fuel containing different concentrations of dispersant (0~0.8 mL/L). See Appendix D for preparation of reference liquids.
• 4.2 Materials:
  • 4.2.1 Hydrocarbon cleaning liquid: a water-white clean kerosene-type fuel containing no surfactants.
  • 4.2.2 Reference base fuel: a kerosene-type fuel containing no surfactants and having a water separation index of 98~100; see Appendix C for preparation method.

5. Instruments and equipment

• 4.1.1 Water separation index tester: model 1104 CRC tester, Figure 1 is the front view, Figure 2 is the instrument flow diagram. See Appendix A for detailed description, and Appendix B for maintenance and troubleshooting.
• 4.1.2 Medical syringe: 2 mL, graduation 0.1 mL, needle length 305 mm, inner diameter 0.30 mm; 1 mL, graduation 0.01 mL.
• 4.1.3 Coalescer filter pads: each test requires a new set of standard filter pads (coarse and fine).
• 4.1.4 Graduated cylinders: 100, 250, 500, 2000 mL (the extracted apparatus name is garbled; requires confirmation against the source standard (source-text extraction)).
• Appendix A supplement: total instrument height 660 mm, total width 966 mm, total depth 356 mm, mass 79.4 kg, minimum base area 0.47 m²; power supply 220 V, 50 Hz single phase, voltage fluctuation not greater than ±15 V.
• Appendix A supplement: coalescer cell orifice 3.55±0.013 mm (the source text source-text extraction writes "3.55t0.013mm", requires confirmation against the source standard (source-text extraction)).
• Appendix A supplement: fuse 4 A.

6. Recommended operating conditions

• Flowmeter calibration: 600 mL fuel temperature 21–27 °C; with emulsification valve closed, start pump and circulate for 1 min; open emulsification valve, pressure gauge reads 138–207 kPa (20~30 psig); adjust float to about scale 20, measure the outflow time of 100 mL fuel; adjust float to scale 16 and 24 and repeat measurement; determine the float position when 40 s flows out 100 mL fuel.
• Instrument cleaning:
  • Isopropanol cleaning: add 200 mL isopropanol, additionally use 50 mL to rinse the inner wall of the storage tank; with all valves closed, start the pump and circulate through the return line for 2 min; open the emulsification valve and adjust to pressure gauge 552 kPa (80 psig), then circulate for 2 min; close the emulsification valve, open the cleaning valve 5 s, allow pressure to drop to about 552 kPa; close the cleaning valve, drain the system; repeat the above operation three times (four times in total).
  • Hydrocarbon cleaning: steps same as isopropanol cleaning.
• Coalescer cell preparation: disassemble, rinse all parts with isopropanol and acetone, thoroughly dry, then install a pair of new filter pads according to Figure 3; the compression gap is specified as 1.588±0.013 mm (0.0625±0.0005 in).
• Reference liquid test: containing different concentrations of dispersant (0~0.8 mL/L), the measured water separation index should conform to the allowable range listed in the table, otherwise re-prepare.
• Instrument preheating: connect power, turn on the voltage regulator switch, when voltage rises to 220 V turn on the instrument power switch, stabilize for 15 min before testing.
• Emulsification conditions: maintain storage tank fuel temperature at 24–27 °C (75–80 °F); adjust emulsification valve pressure to 552±14 kPa (80±2 psig); use a long-needle syringe to inject 2 mL distilled water at a uniform rate into the fuel at the bottom of the storage tank within 60±15 s; continuously circulate and emulsify for 5 min.
• Test run: immediately after emulsifying for 5 min, close the emulsification valve, open the metering valve so that the emulsified mixture flows through the system at a flow rate of 150 mL/min; record the photocell reading every two minutes, record until the eighth minute, and the indication value at the eighth minute is taken as the water separation index value.
• Pump output: under pressure 689 kPa (100 psig), output 415±15 mL/min; check every 100 runs, if lower than 400 mL/min the pump should be replaced.
• Test fuel cleaning flow calibration: the measured outflow time of 100 mL fuel should be 40±0.8 s.

7. Sampling and sample preparation

• 6.2.1 Sample before test: the fuel must not be pre-filtered, so as not to remove surfactants therein; if the fuel has been contaminated by solid particles, separation by sedimentation is allowed before the test.
• 6.2.2 For precautions related to sample containers and sampling techniques, see Appendix E.
• Appendix E Sampling techniques:
  • E1.1 Sample container: preferably an epoxy resin-lined container; carbon steel drums, stainless steel drums, hard glass bottles, and polytetrafluoroethylene drums may also be used; polyethylene and polypropylene plastic drums must not be used; the container must be clean and dry.
  • E1.2 Sample source: the sample should be drawn from flowing fuel, and as far as possible from the water layer at the bottom of the tank.
  • E1.3 Sample line: a short tube with diameter 6~13 mm, open at one end, with a suitable shut-off valve at the other end.
  • E1.4 Sampling: before sampling, first rinse the sample line with an appropriate amount of the fuel sample to be taken, then rinse the sample container with the fuel sample to be taken three times in total, and finally place the sample into the tank and cover it.

8. Analytical procedure

• 7.1 Instrument preheating: connect power, turn on the voltage regulator switch, when voltage rises to 220 V turn on the instrument power switch, stabilize for 15 min before testing.
• 7.2 Instrument cleaning:
  • 7.2.1 Perform instrument cleaning according to the requirements of 6.1.2.
  • 7.2.2 Cleaning of test fuel: according to the 6.1.2.1 isopropanol cleaning method, clean twice with test fuel; according to 6.1.3 prepare the coalescer cell and install it on the instrument; pour 350±5 mL fuel into the storage tank, start the pump; open the emulsification valve, adjust the fuel pressure to 552 kPa (80 psig) and circulate for 5 s, close the emulsification valve, open the metering valve to fill the system with fuel; open and close the metering valve several times continuously to remove air bubbles; open the cleaning valve for 3 s then close it; if flow calibration is required, close all valves, adjust the pressure to 689 kPa (100 psig), let the fuel flow through the system at the float position determined during flowmeter calibration (within 40 s flow through 100 mL), check the flow rate with a calibrated 100 mL graduated cylinder; let the test fuel in the storage tank flow almost completely out; close the metering valve, stop the pump; measure the time for 100 mL fuel to flow out, which should be 40±0.8 s; if not within the specified range, adjust via the flowmeter float position during the second fuel cleaning; add 250±5 mL fuel for the second cleaning and flow calibration; if still not calibrated after the second cleaning, discard the coalescer filter pad and install a new pad, recalibrate the float flowmeter according to 6.1.1.2 and reclean the instrument according to 6.1.2; if flow calibration is normal, turn the adjustment knob to set the photoelectric meter reading to 100; when the fuel in the storage tank is almost completely out, stop the pump and close the metering valve.
  • Note ①: Some fuels may generate static electricity in the storage tank and waste oil discharge section; suitable grounding wires may be connected at the storage tank and waste oil discharge line; if nitrogen can be used to blanket the storage tank and waste oil discharge system, it is even better.
  • Note ②: If the photoelectric meter reading is unstable, check the bulb; if the bulb is not faulty, it may be poor contact of the rheostat or bulb socket, and the electrical contact points can be polished with fine sandpaper.
• 7.3 Formation of emulsion: add 2 L test fuel to the storage tank, start the pump; check the storage tank fuel temperature throughout the test run, turn on the cooling water or heating switch to adjust and maintain the storage tank fuel at 24–27 °C (75–80 °F); open the emulsification valve, adjust the pressure to 552±14 kPa (80±2 psig); use a long-needle syringe to inject 2 mL distilled water directly into the fuel at the bottom of the storage tank at a uniform rate within 60±15 s; record the start time of water injection, and allow the water and fuel mixture to continuously circulate and emulsify for 5 min.
• 7.4 Test run: immediately after emulsifying for 5 min, close the emulsification valve, open the metering valve so that the emulsified mixture flows through the system at a flow rate of 150 mL/min; record the photoelectric meter reading every two minutes, stop recording at the eighth minute, and take the eighth-minute indicated value as the water separation index value of that fuel.
• 7.5 End of test: after recording at the eighth minute, stop the pump, first remove the coalescer cell, connect the jumper plastic line, drain the system according to 6.1.2.3, clean the instrument according to 6.1.2, and then shut down.
• 6.1.2.3 System draining: at the end of each test and after each cleaning, all residual liquid remaining in the instrument must be completely drained; use a plastic tube jumper to replace the coalescer cell, fully open the metering valve, and start the pump; when a large number of air bubbles appear in the jumper line, stop the pump immediately, otherwise the pump running under evacuation conditions is easily damaged.
• 6.1.4 Pump output check: the pump output must be checked regularly, following the procedure in Appendix B1.1.
• 6.1.5 Test of reference liquid: the reference liquid (for instrument calibration) contains different concentrations of dispersant (0~0.8 mL/L); determine its water separation index, and the result should conform to the allowable range in the table below, otherwise prepare the reference liquid again; the reference liquid test is carried out according to the method in Appendix D.

Table of water separation index requirements for reference liquids

Note: For new instruments and when major parts of the instrument are replaced or abnormalities are found, verification must be carried out with the reference liquid, and only when the results meet the requirements in the above table may fuel determination be carried out.

1. Based on the determination results of 8 laboratories, with a confidence level of 95%.

9. Qualitative and quantitative determination and calculation formulas

• Water separation index: a numerical value used to evaluate the ease or difficulty of separating water when jet fuel passes through a coalescing medium, expressed in units of 0~100; clean and transparent jet fuel is 100.
• Result reading: the photoelectric meter indicated value at the eighth minute of the test run is taken as the water separation index value of that fuel.
• Report: take the arithmetic mean of two results that meet the repeatability requirement as the test result.
• Calculation formula: not provided in the available source.

10. Precision

• Judge the reliability of the determination results according to the following provisions (95% confidence level).
• 8.1 Repeatability: the difference between two results obtained by repeated determination by the same operator shall not be greater than the value shown by the repeatability curve in Figure 4.
• 8.2 Reproducibility: the difference between two results submitted by different laboratories shall not be greater than the value shown by the reproducibility curve in Figure 4.
• Figure 4 specific values: the original is a curve graph and does not give specific values; not provided in the available source.

11. Report

Take the arithmetic mean of two results that meet the repeatability requirement as the test result.

12. Reference documents

• ASTM D2550-85 "Determination of Water Separation Index of Jet Fuel" (referenced and adopted).
• SY 2233-80 "Determination of Water Separation Index of Jet Fuel" (withdrawn).
• Appendix A: Detailed description of the water separation index tester (supplementary document).
• Appendix B: Instrument maintenance and troubleshooting (supplementary document).
• Appendix C: Preparation of reference base fuel (supplementary document).
• Appendix D: Preparation and testing of reference liquid (supplementary document).
• Appendix E: Sample containers and sampling techniques (supplementary document).

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 for questions and answers