SH/T 0241-1992 Determination of static thermal stability of jet fuels

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

• Method number: SH/T 0241-92 (confirmed in 2004)
• Full name: Determination of static thermal stability of jet fuels
• English name: not provided in the available source
• Replacement relationship: replaces SY 2232-82
• First issued: 1977
• Approval/implementation: approved by China Petrochemical Corporation in 1992-05-20, implemented in 1992-05-20

2. Scope of application and non-applicability

• Scope of application: This standard applies to jet fuels.
• Non-applicability: not provided in the available source.

3. Method principle

The thermal stability of jet fuel is evaluated by the amount of precipitate formed when a 50 mL sample is oxidized at 150℃ for 4 h.

4. Reagents and materials (purity / preparation)

4.1 Reagents

• 4.1.1 Petroleum ether: analytical reagent, 30～60℃ or 60～90℃.
• 4.1.2 Anhydrous ethanol: chemical reagent.
• 4.1.3 Benzene: chemical reagent.
• 4.1.4 Anhydrous ethanol-benzene mixed liquid: prepared by mixing anhydrous ethanol and benzene in a volume ratio of 1:4.

4.2 Materials

• 4.2.1 Quantitative filter paper: medium speed.
• 4.2.2 Sandpaper (or abrasive cloth): grit 220 or 180.
• 4.2.3 Copper strip: material meets the requirements of T1 in GB/T 5231, length 24.5～25.0 mm, width 19.5～20.0 mm, thickness 2.5～3.0 mm. Each copper strip has one hole of diameter 1～2 mm, with the hole center located 2～3 mm from the edge at the center of the width.
• 4.2.4 Nickel-chromium wire: diameter 0.2～0.5 mm.

5. Apparatus and equipment

• 5.1 Static thermal stability tester (see Figure 1): includes a steel bomb (see Figure 2), a hard glass oil cup (see Figure 3), and a temperature controller. Note: The LJRY-01 model jet fuel static thermal stability tester manufactured by Lanzhou Refining and Chemical General Factory has passed appraisal and may be used.
• 5.2 Acid-resistant glass filter funnel: filter plate pore diameter 3～5 μm.
• 5.3 Suction flask: 250 or 500 mL.
• 5.4 Glass beaker or enamel cup: 2000 mL.
• 5.5 Polytetrafluoroethylene gasket: thickness 1.5～2 mm.
• 5.6 Steel bomb base.
• 5.7 Adjustable wrench: 254 mm.
• 5.8 Mercury thermometer: 0～360℃, scale division 1℃.

6. Recommended operating conditions

• Oxidation temperature: 150℃±2℃
• Oxidation time: 4 h
• Sample amount: 50 mL
• Drying temperature (filter funnel): 105℃±2℃
• Drying time (filter funnel): 1 h
• Cooling time (desiccator): 30 min

7. Sampling and sample preparation

• 6.5 The sample is filtered with quantitative filter paper; samples with obvious water content are dehydrated with freshly calcined sodium sulfate and then filtered.
• 7.1 Take 50 mL of the filtered sample and inject it into a clean oil cup; place one copper strip in each oil cup and suspend it in the middle of the sample with nickel wire; then place the oil cup into a clean steel bomb and tighten the bomb cover on the bomb base with an adjustable wrench.

8. Analytical procedure

• 6.1 Immerse the acid-resistant glass filter funnel in potassium dichromate cleaning solution; after 12 h, remove it, rinse it by suction filtration with distilled water until the filtrate is neutral, and air-dry it.
• 6.2 Place the cleaned acid-resistant glass filter funnel in an oven at 105℃±2℃ and dry for 1 h; remove and place in a desiccator to cool for 30 min; weigh to the nearest 0.0002 g. Then place it in the oven again and dry for 30 min. Repeat drying, cooling, and weighing until the difference between consecutive weighings does not exceed 0.0004 g.
• 6.3 Polish the copper strip with sandpaper (or abrasive cloth) until smooth, bright, and free of obvious machining marks. Then wash with anhydrous ethanol-benzene mixed liquid and air-dry on filter paper.
• 6.4 Turn on the power of the temperature controller and raise the metal bath temperature to 150℃±2℃.
• 6.6 Add an appropriate amount of water to a 2000 mL beaker or enamel cup and heat to a state that is about to boil but not boiling, for checking the seal of the steel bomb.
• 7.2 Lift the steel bomb with a metal hook and immerse it in the nearly boiling water to check the sealing condition. If bubbles escape around the gasket, tighten again and repeat the leak test until no gas leaks.
• 7.3 Place the steel bombs loaded with samples diagonally into the metal aluminum bath holes at a temperature of 150℃±2℃, record the time, cover with the insulation cover, and after maintaining constant temperature for 4 h, cut off the power. Quickly remove the steel bombs with a metal hook in the order they were placed, cool in running water to room temperature, wipe off water on the bomb bodies, open the bomb covers on the bomb base, take out the oil cups, and wait for filtration.
• 7.4 Before filtration, install the constant-weight acid-resistant glass filter funnel on a suction flask connected to a vacuum pump.
• 7.5 First gradually pour the sample along a glass rod into the acid-resistant glass filter funnel for suction filtration, then wash the precipitate successively with petroleum ether and gradually transfer the precipitate into the acid-resistant glass filter funnel; the petroleum ether used to wash the oil cup and copper strip should be poured successively into the acid-resistant glass filter funnel; wash the precipitate with petroleum ether until the filtrate passing through the acid-resistant glass filter funnel is colorless.
• 7.6 Place the acid-resistant filter funnel with precipitate in an oven at 105℃±2℃ and dry for 1 h, and bring the acid-resistant glass filter funnel to constant weight according to clause 6.2.

9. Qualitative and quantitative determination and calculation formula

The amount of precipitate after oxidation of the sample, X (mg/100 mL), is calculated according to the following formula:

X = 2(m₂ − m₁)

Where:

• m₁ —— mass of the acid-resistant glass filter funnel, mg;
• m₂ —— mass of the acid-resistant glass filter funnel and precipitate, mg.

10. Precision

Repeatability: the difference between two repeated determination results shall not exceed 20% of the smaller result.

11. Report

Take the arithmetic mean of two repeated determination results as the sample determination result.

12. Referenced documents

• GB/T 5231 Wrought copper and copper alloys—Chemical composition and product forms

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