SH/T 0062-1991 Determination of Depentanization of Gasoline and Naphtha

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Card type: Test method

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

• Standard number: SH/T 0062-91 (confirmed in 2001)
• Chinese title: Determination of Depentanization of Gasoline and Naphtha
• English title: not provided in the available source (the English name is not given in the main text)
• Replacement relationship: not provided in the available source
• Reference adoption: American Society for Testing and Materials standard ASTM D 2001-86 "Test Method for Depentanization of Gasoline and Naphtha" (see additional notes)
• Approval/implementation: approved by China Petrochemical Corporation 1991-06-28, implemented on 1992-07-01

2. Scope of application and non-applicability

• Applicable to: gasoline, naphtha, and similar petroleum fractions, for preparing samples for methods such as GB/T 11132.
• Method content: specifies a method for removing pentane and lighter hydrocarbons from a sample by distillation.
• Not applicable: this standard is not applicable to other uses not specified in the scope of application (see the note to Chapter 3).

3. Method principle

Distill the 50 mL sample under specified conditions; the distillate is C5 hydrocarbons and lighter fractions, and the residue is C6 hydrocarbons and heavier fractions; measure the volume of the residue. Note: Under the specified conditions, some C6 hydrocarbons and lighter hydrocarbons remain in the residue, while some C6 hydrocarbons and heavier hydrocarbons are carried into the distillate; their amount is generally below 2% of the sample volume, which is suitable for the uses specified in the scope of application of this standard; however, if their amount is expressed as volume percent of the distillate or residue, the result may be higher, so this standard is not applicable to other uses not specified in the scope of application.

4. Reagents and materials (purity / preparation)

• 4.2 Materials
  • 4.2.1 Column packing: stainless steel material.
    • a. Heli-Pak B column packing: dimensions as shown in Figure 6.
    • b. Heli-Pak C column packing: dimensions as shown in Figure 6; or short coarse-tube porous metal packing: 4.06 mm × 4.06 mm.
  • 4.2.2 Solid carbon dioxide.
  • 4.2.3 Hydrocarbon-insoluble grease: such as silicone, starch-glycerol, or metal soap, etc.
• 5 Reagents
  • 95% Ethanol: chemically pure.

5. Apparatus and equipment

• 4.1 Apparatus
  • a. Distillation column: glass column with vacuum jacket, dimensions as shown in Figure 1.
  • b. Reflux condenser: dimensions as shown in Figure 2.
  • c. Light fraction collector: dimensions as shown in Figure 3.
  • d. Receiver: 15 mL, dimensions as shown in Figure 4.
  • e. Thermometer: internal-standard mercury thermometer, 10 to 80℃ (the source text source-text extraction is "10 - 8090", requires confirmation against the source standard (source-text extraction)), scale division value is 0.5℃. Dimensions as shown in Figure 5.
  • f. Distillation flask: 100 mL, with 24/40 taper joint.
  • g. Vacuum flask: 200 mL.
  • h. Variable transformer: 1000 W (the source text source-text extraction is "loowo", requires confirmation against the source standard (source-text extraction)).
  • i. Heating mantle: suitable for 100 mL distillation flask.
  • j. Cold water bath: provides circulating water at 4 to 10℃.
  • k. Graduated cylinder: 50 mL, with graduations of 1 mL.
• Figure 7 Composition of the depentanization apparatus: 1— heating mantle support; 2— heating mantle; 3— receiver; 4— vacuum flask; 5— light fraction collector; 6— cooling water pipe; 7— reflux condenser; 8— thermometer; 9— distillation column; 10— column packing; 11— distillation flask; 12— heating mantle lead; 13— support; 14— voltmeter; 15— voltage regulator; 16— indicator light; 17— power switch.

6. Recommended operating conditions

• Reflux ratio: 1:1 (adjust the condenser position so that the oil drops from one of the two drip tips fall into the receiver, while the oil drops from the other drip tip flow back into the distillation column; maintain this position throughout the distillation process).
• Distillation rate: counted by the oil drops falling from each drip tip of the reflux condenser, 30 to 40 drops per 30 s.
• Cooling water: 4 to 10℃ circulating water passes through the reflux condenser.
• Cut temperature: the thermometer indicates 49℃ (based on 101.3 kPa (760 mmHg) standard atmospheric pressure; otherwise correct the temperature according to GB/T 6536, corrected to 0.5℃).
• Fill the vacuum flask and light fraction collector with a liquid mixture of 95% ethanol (or other suitable liquid) and solid carbon dioxide, in an amount of two-thirds of the container.

7. Sampling and sample preparation

• 7.1 Measure the temperature of the sample, take 50 mL of sample with a graduated cylinder and transfer it into the distillation flask, immediately connect the distillation flask to the distillation column, and install the heating mantle.
• 6.8 Record the atmospheric pressure.

8. Analytical procedure

• 6 Preparatory work
  • 6.1 Column packing: fill the recess at the bottom of the column with Heli-Pak C packing to a height of about 25 mm. If the packing falls down, the first 2 to 3 pieces of packing may be coiled and packed. Then fill the column with Heli-Pak B packing until no more than 25 mm from the top of the distillation column (the exact method of packing the column does not affect the packing efficiency).
  • 6.2 Connect the distillation column, reflux condenser, light fraction collector, receiver, etc., and install them on a suitable support (see Figure 7).
  • 6.3 Insert the thermometer (see Figure 5) into the side branch at the top of the distillation column. Note: The indication of the indicating thermometer at the cut temperature 49℃ must be calibrated.
  • 6.4 Fill the vacuum flask and light fraction collector with a liquid mixture of 95% ethanol (or other suitable liquid) and solid carbon dioxide (Caution: extremely cold, see Appendix A1), in an amount of two-thirds of the container.
  • 6.5 Immerse the receiver in the vacuum flask containing the liquid mixture.
  • 6.6 Circulate water at 4 to 10℃ through the reflux condenser.
  • 6.7 Apply hydrocarbon-insoluble grease to all joints of the depentanization apparatus.
  • 6.8 Record the atmospheric pressure.
• 7 Test procedure
  • 7.1 Measure the temperature of the sample, take 50 mL of sample with a graduated cylinder and transfer it into the distillation flask, immediately connect the distillation flask to the distillation column, and install the heating mantle.
  • 7.2 Turn on the power and heat the sample in the distillation flask uniformly. Before reflux oil drops are produced at the top of the distillation column, low-boiling light fractions will condense in the light fraction collector and flow into the receiver.
  • 7.3 When reflux oil drops are produced at the top of the distillation column, immediately adjust the position of the condenser so that the oil drops from one of the two drip tips (Caution: extremely flammable liquid, see Appendix A2) fall into the receiver, while the oil drops from the other drip tip flow back into the distillation column. Maintain this position of the reflux condenser throughout the distillation process to obtain a reflux ratio of 1:1.
  • 7.4 The distillation rate is counted by the oil drops falling from each drip tip of the reflux condenser, 30 to 40 drops per 30 s.
  • 7.5 Continue distillation until the thermometer indicates 49℃. When this temperature is reached, turn the reflux condenser so that the oil drops from both drip tips fall back into the distillation column. Cut off the power and lower the heating mantle. The above steps must be carried out quickly and continuously. The thermometer 49℃ reading is based on 101.3 kPa (760 mmHg) standard atmospheric pressure; otherwise correct the temperature according to GB/T 6536, corrected to 0.5℃.
  • 7.6 Allow the residue in the distillation flask, together with the distillation column, to cool for 30 min.
  • 7.7 Remove the distillation flask from the distillation column, carefully transfer the residue in the distillation flask into the same graduated cylinder used for taking the sample, read the volume, and measure the temperature.

9. Qualitative and quantitative determination and calculation formula

The volume percentage of the residue in the sample X [% (V/V)] is calculated according to the following formula:

X = (V1 / V2) × 100

Where:

• V1 — volume of the residue, mL;
• V2 — volume of the sample, mL.

Note: If the temperature of the sample and the temperature of the residue differ by more than 11℃ (the source text source-text extraction is "11`C", requires confirmation against the source standard (source-text extraction)), then correct the volumes of both parts to the volume at 20℃ according to GB/T 1885.

10. Precision

Use the following provisions to judge the reliability of test results (95% confidence level).

• 9.1 Repeatability: the difference between two results obtained by the same operator in repeated determinations shall not exceed 2% (V/V).
• 9.2 Reproducibility: the difference between two results submitted by different laboratories shall not exceed 4% (V/V).
• Note: This precision applies only to samples containing C5 hydrocarbons and lighter fractions in the range of 5% to 25% (V/V) (the source text source-text extraction is "q hydrocarbons and lighter fractions range is 5% to 25%( V/", requires confirmation against the source standard (source-text extraction)).

11. Report

Take the arithmetic mean of two results from repeated determinations (rounded to one decimal place) as the determination result of the sample.

12. Referenced documents

• GB/T 1885 Petroleum measurement tables
• GB/T 6536 Test method for distillation of petroleum products
• GB/T 11132 Test method for hydrocarbon types in liquid petroleum products (fluorescent indicator adsorption method)
• Appendix A Safety protection instructions (reference item): A1 solid carbon dioxide; A2 oil drops (extremely flammable liquid)

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