GB/T 11128-1989 Determination of Glow Value of Jet Fuel

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Card type: Test method

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

• Standard number: GB 11128-89
• Chinese name: Determination of Glow Value of Jet Fuel
• English name: Aviation turbine fuels-Determination of luminometer numbers
• Replacement relationship: From the date of implementation of this standard, the former Ministry of Petrochemical Industry standard SY 2225—77 "Determination of Glow Value of Jet Fuel" is void.
• Reference adoption: American Society for Testing and Materials standard ASTM D1740-85 "Standard Test Method for Glow Value of Aviation Turbine Fuels".
• Technical administration: Technical administration by the Research Institute of Petroleum Processing; drafting: Research Institute of Petroleum Processing; main drafter: Zang Yurong.
• Approval/implementation: approved by China Petrochemical Corporation 1989-03-31, implemented on 1990-04-01.

2. Scope of application and non-applicability

• Applicable to jet fuels and similar distillate fuels.
• Not applicable: not provided in the available source.

3. Method principle

The test sample is placed in the wick-type small oil lamp of the glowmeter and burned. The flame radiation intensity is measured through a filter and photocell device. At the same time, the temperature rise value at the cross-section of the oil lamp measured by a thermocouple directly above the flame is used to plot a curve. The temperature rise value of the sample is compared with the flame temperature rise values measured under a constant radiation level for the reference samples tetrahydronaphthalene and isooctane respectively. To ensure that all instruments have the same constant evaluation reference, the flame radiation intensity at the smoke point of tetrahydronaphthalene is specified as the reference. The glow value is calculated by dividing the difference between the temperature rise value of the sample and the temperature rise value of tetrahydronaphthalene by the difference between the temperature rise values of isooctane and tetrahydronaphthalene.

4. Reagents and materials (purity / preparation)

• 7.1 Tetrahydronaphthalene: analytical reagent, n²¹ 1.5396–1.5410 (the source text writes "n21.5396–1.5410", requires confirmation against the source standard (source-text extraction)).
• 7.2 Isooctane: analytical reagent, n²¹ 1.3913–1.3917 (the source text writes "[unreadable character]1.3913–1.3917", requires confirmation against the source standard (source-text extraction)).
• 7.3 Acetone: analytical reagent.
• 7.4 Petroleum ether: 60~90°C, analytical reagent.
• 7.5 Toluene: analytical reagent.
• 7.6 Anhydrous methanol: analytical reagent.
• Note: Among the reagents, tetrahydronaphthalene combustible vapor is toxic and isooctane is extremely flammable. Special care must be taken during operation, attention must be paid to ventilation, and open flames are strictly prohibited.
• Materials:
  • 6.2.1 Wick: meets the wick requirements of GB 382.
  • 6.2.2 Test tube brush.
  • 6.2.3 Lens cleaning paper.

5. Instruments and equipment

• 6.1.1 Glowmeter: CRC type glowmeter (see Figure 1).
• 6.1.2 Wick-type small oil lamp: the sample is burned therein.
• 6.1.3 Filter and photocell circuit: should ensure flame radiation intensity within the range of 4800~7000Å.
• 6.1.4 A dual-element thermocouple circuit and a potentiometer indicated by a digital output meter.
• 6.1.5 Fat extractor.
• 6.1.6 Graduated cylinder: 25 mL.
• Figure 1 Glowmeter schematic labels: 1— wick-type small oil lamp; 2— orange filter; 3— photocell; 4— amplifier; 5— glowmeter meter; 6— flame thermocouple; 7— potentiometer; 8— atmospheric thermocouple; 9— air inlet.

6. Recommended operating conditions

• 6.1.3 The filter and photocell circuit should ensure flame radiation intensity within the range of 4800~7000Å.
• 8.4 The thermocouple sleeve is fixed on the center line of the lamp, and its bottom end should be accurately located 25.4 mm above the wick sleeve.
• 9.1 Note ①: The distance from the flame to the thermocouple is not allowed to be less than 3.2 mm, or the temperature indicator reading to exceed 538°C.
• 9.1 Note ②: The manufacturer has adjusted all glowmeters so that the reading at the smoke point of tetrahydronaphthalene is 45~55; if the instrument exceeds this range, the internal resistance located between the two amplifier tubes can be adjusted (remove the rear cover of the instrument) until the glowmeter meter reading reaches 45.
• 8.2.1 Wick drying: dry at 105±5°C for 30 min (the source text writes "1055 °CC", requires confirmation against the source standard (source-text extraction)).
• 8.2.2 Small oil lamp drying: dry in an oven at 105±5°C (the source text writes "105[unreadable sign]5CC", requires confirmation against the source standard (source-text extraction)).
• 8.2.3 The top end of the wick is 6.4 mm higher than the sleeve.
• 9.1 Burn tetrahydronaphthalene for 15 min to warm up the instrument.
• 9.2 After stabilizing for 30 s, stabilize for a further 5 min and record the reading; each time the small oil lamp is raised so that the glowmeter meter reading increases by nearly 5 units, record after stabilizing for 5 min.
• 8.5.2 Note: Do not charge for more than 18 h; digital display symbols: HI means temperature out of range; HELP means battery discharge; C means degrees Celsius.
• 8.5.3 Instrument power supply: four rechargeable batteries of model 1.2AHR SC size; the 115V charger may only be used on the 115V line.

7. Sampling and sample preparation

• 9.1 At room temperature, take 20 mL of tetrahydronaphthalene and inject it into a clean, dry wick-type small oil lamp.
• 8.1 Lamp cleaning: Before each test, use a small test tube brush dipped in acetone or petroleum ether to clean the top and inner side of the wick sleeve (inside the lamp body). During cleaning, use lens cleaning paper to protect the filter. After cleaning, check whether there are spots on the filter; if spots are found, wipe them clean with lens cleaning paper. If necessary, first move the oil lamp away, then loosen the screws of the filter retaining ring, remove the filter for cleaning, and after the lamp is restored to its original position, it should be checked with reference fuels (tetrahydronaphthalene and isooctane).
• 8.2.1 The wick is extracted in a fat extractor with a mixed liquid of equal volumes of toluene and anhydrous methanol for at least 25 cycles. Take out the wick and place it in a ventilated place for 5 min, so that the residual solvent in the local part of the wick evaporates naturally and dries, then place it in an oven and dry at 105±5°C for 30 min, and store it in a desiccator for later use. Note: If no suitable extractor is available, the wick may be treated and dried according to GB 382. When the determination results are disputed, treat according to 8.2.1 and clean all parts with acetone.
• 8.2.2 The small oil lamp is thoroughly cleaned in acetone or petroleum ether, then placed in a ventilated place to let the residual solvent evaporate, and then placed in an oven at 105±5°C to dry. Note: If the vapors of the sample, acetone, or petroleum ether are not completely removed during the cleaning and drying of the small oil lamp, erroneous test results may be obtained.
• 8.2.3 Insert the dried wick into the wick sleeve of a clean small oil lamp. A thin iron wire may be used to hook one end of the wick and pull the wick through the tube, but do not twist the wick. Then use a clean blade or other sharp tool to cut the top end of the wick flat. Push the lower part of the wick by hand so that its head extends upward, then pull the wick upward, and loosen and turn the end of the wick so that the wick has no distortion. Then pull the wick downward until its top end is 6.4 mm higher than the sleeve. Trim the uneven part of the wick head again so that it meets the requirements. Note: ① Some blades are coated with a chemical protective layer, which should first be removed with solvent. ② Another method for preparing an untwisted, neat wick is to use a set of wick trimmers. Insert the wick trimmer base into the top of the wick tube, insert long-nose three-pronged tweezers through the wick tube and trimmer base, clamp the wick, and carefully pull it out of the tube without twisting. Use a sharp blade to cut the wick flush with the trimmer base surface, and remove the bad head. When the trimmer base is removed, the wick will be at the appropriate height in the tube. Then insert the wick tube into the small oil lamp and tighten it in the direction of the stone spiral. Place the small oil lamp into the lamp chamber.
• 8.3 Glowmeter: It has a base for adjusting the inclination of the lamp chamber. Use the small level on the flame height adjustment ring to check the level of the lamp chamber. The flame axis of the oil lamp must be vertical.
• 8.5.1 Potentiometer: Adjust according to the instrument instruction manual. If the potentiometer cannot be adjusted to zero, replace the battery inside the potentiometer.
• 8.5.2 Temperature indicator: According to the instrument instruction manual, place the power switch in the "Celsius" position; no additional adjustment is required. After the test, turn the power "off" to save battery.
• 8.6 Glowmeter meter: Adjust the zero point according to the instrument instruction manual. Then turn the lower right knob to the A1, A2, B1 and B2 positions to check the battery voltage. If the pointer stops at the corresponding scale on the meter dial in each position, the battery is considered acceptable and the instrument may be used. If the battery power is insufficient, it should be replaced. When replacing the "B" battery, the photocell battery placed in the photocell box should also be replaced.

8. Analysis procedure

• 9.1 At room temperature, take 20 mL of tetrahydronaphthalene and inject it into a clean, dry wick-type small oil lamp. Insert the wick sleeve through the upper opening of the small oil lamp and tighten it. Use a small wooden stick to pass through the vent hole at the bottom of the wick-type small oil lamp so that the fuel vent hole is unobstructed. After the fuel rises to the top of the wick, place the wick-type small oil lamp into the lamp chamber and light the small oil lamp. If soot has accumulated on the thermocouple sleeve, extinguish the flame, wipe the sleeve clean, lower the small oil lamp slightly, and light it again. Through the observation hole in the center of the lamp door, make sure the flame burns without smoke. Under these conditions, let tetrahydronaphthalene burn for 15 min to warm up the instrument.
• 9.2 After the instrument is warmed up, lower the small oil lamp so that the glowmeter meter pointer approaches 30, then adjust the glowmeter meter and potentiometer to "zero". Then turn the lower right knob of the glowmeter meter to the "test" position. After stabilizing for 30 s, at this position, with the outer door of the glowmeter lamp chamber closed and no air flow, stabilize for a further 5 min, and record the glowmeter meter and temperature indicator readings. Then raise the small oil lamp so that the glowmeter meter reading increases by nearly 5 units. After stabilizing for 5 min, record the glowmeter meter and temperature indicator readings again according to the above test steps. Each time the small oil lamp is raised by 5 units, repeat the above steps until four data points are obtained. The flame height of the last data point is selected so that a small glowing flame tail (slight smoking) just appears at the top of the flame, that is, exactly at the smoke point of tetrahydronaphthalene. Note: If a small grid screen of 40~60 mesh is placed in front of the door, equilibrium can be easily re-established.
• 9.3 Plot the data points as a curve of glowmeter meter reading value against the lamp temperature rise value; all points should fall on a smooth curve. Its highest point (the smoke point of tetrahydronaphthalene) represents the evaluation reference for the instrument when testing all samples. Repeat this four times to determine the average value of the instrument evaluation reference (see Figure 2).
• 9.4 According to the procedure described in clauses 9.1 to 9.3, test two samples of isooctane, but four data points must be measured each time, of which two points must be below the evaluation reference calibrated with tetralin for the instrument, and the other two points must be above this reference. Among the four data points, the temperature rise between every two points must be about 10 glow value units. One isooctane sample must be placed before measuring the test sample, and the other after the test sample has been measured. Draw two curves, and find the lamp temperature rise value of each isooctane sample at the evaluation reference (see Figure 3). Calculate their average value. Note: ① If there are many test samples to be measured, and all tests are conducted on the same day, the second isooctane sample may be tested after all test samples. ② High glow value fuels readily form water vapor condensation; using a small flame to preheat the interior of the lamp chamber or adopting a method of gradually and slowly increasing the temperature can both prevent water vapor condensation. Once water vapor condensation occurs, the glowmeter reading will become unstable, and moisture will appear on the glass of the observation hole. If water vapor condensation occurs, the sample may be burned with the lamp door removed until the moisture on the filter and the small oil lamp completely disappears. ③ Fuels with very low glow values often smoke when the glowmeter reading is relatively low; by observing through the observation hole of the lamp door, keep the flame of the low temperature rise value sample from smoking. Once a smoking flame appears, wipe the filter and thermocouple sleeve clean.
• 9.5 According to the method for determining isooctane, measure the lamp temperature rise value of the test sample (see Figure 4). Using the difference between this temperature rise value and the temperature rise value of tetralin, divided by the difference between the temperature rise values of isooctane and tetralin, calculate the glow value of the test sample.

9. Qualitative and Quantitative and Calculation Formula

• 10 The glow value X of the test sample is calculated according to the following formula:
  • The original formula part source-text extraction is missing, only symbol explanations are seen:
    • ΔT₁ (written in the original as “AT,”) — the flame temperature rise value of the test sample flame radiation intensity at the evaluation reference, °C;
    • ΔT₂ (written in the original as “AT;”) — the flame temperature rise value of tetralin flame radiation intensity at the evaluation reference, °C;
    • ΔT₃ (written in the original as “AT;”) — the flame temperature rise value of isooctane flame radiation intensity at the evaluation reference, °C.
  • The ΔT of tetralin and isooctane is the average value at the evaluation reference of tetralin.
  • Formula body: not provided in the available source (source-text extraction missing), requires confirmation against the source standard (source-text extraction).
• 12.1 Report the result of the glow value, with the effective value taken to one decimal place.
• 12.2 Take the arithmetic mean of two results from repeated determinations as the glow value of the test sample.

10. Precision

Judge the reliability of the determination results according to the following provisions (95% confidence level) (written in the original as “96% confidence level”, requires confirmation against the source standard (source-text extraction)).

• 11.1 Repeatability: the difference between two results from repeated determinations by the same operator shall not be greater than 6 (written in the original as “shall not be greater 6.”, unit requires confirmation against the source standard (source-text extraction)).
• 11.2 Reproducibility: the difference between two results respectively proposed by different laboratories shall not be greater than 8.8 (written in the original as “shall not be greater than 8.8”).

11. Report

• 12.1 Report the result of the glow value, with the effective value taken to one decimal place.
• 12.2 Take the arithmetic mean of two results from repeated determinations as the glow value of the test sample.

12. Reference Documents

• GB 382 Kerosene smoke point determination 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 Reference for Questions and Answers