GB/T 255-1977 Determination of distillation range of petroleum products

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Card type: Test method

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

• Standard number: GB 255-77
• Chinese name: Determination of distillation range of petroleum products
• English name: Petroleum products-Determination of distillation characteristics
• Replacement relationship: replaces GB 255-64
• Confirmation status: confirmed in 1988
• Publication/implementation: issued by the National Bureau of Standards and Metrology in 1977-11-08, implemented in 1978-01-01
• Proposed/drafted: this standard was proposed by the Ministry of Petrochemical Industry of the People's Republic of China; drafted by the Comprehensive Research Institute of the Research Institute of Petroleum Processing

2. Scope of application and non-applicability

• Applicable to the determination of the distillation composition of engine fuels, solvent naphtha and light petroleum products.
• Not applicable: not provided in the available source.

3. Method principle

100 milliliters of sample, under the specified apparatus and test conditions, are distilled according to the requirements of the product properties, the temperature readings and condensate volume are systematically observed, and then the test results are calculated from these data.

4. Reagents and materials (purity / preparation)

• Ice blocks or snow: used when distilling gasoline to fill the water bath and cover the condenser tube; when ice or snow is lacking, cold water may be used instead for acceptance tests according to 3.4, but ice or snow must be used for arbitration tests.
• Cold water: used for condenser inlet/outlet water; when distilling solvent naphtha, jet fuel, kerosene and other petroleum products, the outlet water temperature is adjusted to not higher than 30 ℃; when distilling waxy liquid fuels (pour point higher than -5 ℃), the water temperature is controlled at 50~70 ℃.
• Light gasoline: used to wash the distillation flask, then blow dry with air.
• Chromic acid cleaning solution or alkaline cleaning solution: used when necessary to remove carbon deposits in the distillation flask.
• Collodion: applied to the cork stopper connections.
• Cotton: used to plug the mouth of the graduated cylinder.
• Metal weight: used when distilling gasoline to press the bottom of the graduated cylinder so that the graduated cylinder cannot float up.
• Soft cloth (wrapped on copper wire or aluminum wire): used to wipe the inner wall of the condenser tube.
• Purity and specific preparation: not provided in the available source.

5. Apparatus and equipment

• Petroleum products distillation range tester: complies with the provisions of GB 515 "Technical conditions for distillation range determination apparatus for petroleum products". The components include: 1— condenser tube, 2— condenser, 3— water inlet branch pipe, 4— water outlet branch pipe, 5— distillation flask, 6— graduated cylinder, 7— thermometer, 8— asbestos pad, 9— upper shield, 10— blast burner, 11— lower shield, 12— support, 13— bracket.
• Stopwatch.
• Blast burner or electric furnace with autotransformer.
• Thermometer: complies with GB 514 "Technical conditions for liquid thermometers for petroleum product testing".
• 100 milliliter graduated cylinder: clean and dry; used for measuring the sample.
• 10 milliliter graduated cylinder: used for measuring the volume of residue.
• Tall beaker: when distilling gasoline, the graduated cylinder is immersed in it, and the liquid level in the beaker is higher than the 100 milliliter mark of the graduated cylinder.
• Asbestos pad: complies with the provisions for A, B and C in GB 515 Figure 7, selected according to the sample type.

6. Recommended operating conditions

• Condenser temperature:
  • Distilling gasoline: the water bath temperature is maintained at 0~5 ℃.
  • Distilling solvent naphtha, jet fuel, kerosene and other petroleum products: the outlet water temperature is not higher than 30 ℃.
  • Distilling waxy liquid fuels (pour point higher than -5 ℃): water temperature 50~70 ℃.
• Time to heat to the first drop of distillate:
  • Gasoline or solvent naphtha: 5~10 minutes.
  • Aviation gasoline: 7~8 minutes.
  • Jet fuel, kerosene, light diesel: 10~15 minutes.
  • Heavy diesel or other heavy oil materials: 10~20 minutes.
• Distillation rate: uniform, 4–5 milliliters distillate per minute, generally equivalent to 20–25 drops per 10 seconds.
• Heavy diesel: the initial 10 milliliters distill at a rate of 2–3 milliliters per minute, thereafter at 4–5 milliliters per minute.
• When distilling gasoline, neither the heater nor the lower shield temperature should be higher than room temperature.
• When distilling gasoline, the water temperature of the tall beaker is maintained at 20±3 ℃ (the source source-text extraction is "203°", requires confirmation against the source standard (source-text extraction)).
• Sample injection temperature into the distillation flask: 20±3 ℃.
• Reading precision: all readings are accurate to 0.5 milliliters and 1 ℃.
• Residue cooling temperature: 20±3 ℃ (the source source-text extraction is "203C", requires confirmation against the source standard (source-text extraction)).

7. Sampling and sample preparation

• If the sample contains water, dehydration should be carried out before the test.
• Use a clean, dry 100 milliliter graduated cylinder to measure 100 milliliters of sample and inject it into the distillation flask; do not let the liquid flow into the side arm of the distillation flask.
• The sample volume in the graduated cylinder is read at the lower edge of the meniscus; when observing, keep the eye at the same level as the liquid surface.
• When injecting into the distillation flask, the sample temperature should be 20±3 ℃.
• Note: when determining waxy liquid fuels, the sample temperature may be appropriately raised so that it is measured in a flowing state; in case of dispute, the temperature for measuring the sample should be consistent with the receiving temperature.

8. Analysis procedure

• 3.2 Before distillation, the condenser tube 1 of condenser 2 should be wiped on the inner wall with a soft cloth wrapped on copper wire or aluminum wire to remove liquid remaining from the previous distillation.
• 3.3 When distilling gasoline, the water inlet branch pipe 3 of condenser 2 should be fitted with a rubber tube with a clamp, then fill the water bath with ice blocks or snow, and inject cold water to cover the condenser tube; during distillation, the water bath temperature is maintained at 0~5 ℃. When ice or snow is lacking, cold water may be used instead for acceptance tests according to 3.4; ice or snow must be used for arbitration tests.
• 3.4 When distilling solvent naphtha, jet fuel, kerosene and other petroleum products, both the water inlet and water outlet branch pipes of the condenser should be fitted with rubber tubes, allowing cold water to flow into the water bath through the water inlet branch pipe 3, and then flow away through the water outlet branch pipe 4; the outlet water temperature is adjusted to not higher than 30 ℃. During the distillation of waxy liquid fuels (pour point higher than -5 ℃), the water temperature is controlled at 50~70 ℃.
• 3.5 The distillation flask 5 may be washed with light gasoline, then blow dry with air; when necessary, use chromic acid cleaning solution or alkaline cleaning solution to remove carbon deposits.
• 3.8 (source numbering) Use a clean, dry 100 milliliter graduated cylinder 6 to measure 100 milliliters of sample and inject it into the distillation flask; do not let the liquid flow into the side arm; calculate the volume at the lower edge of the meniscus; injection temperature 20±3 ℃.
• 3.7 Tightly insert the cork stopper fitted with thermometer 7 into the mouth of the distillation flask containing the sample, so that the thermometer and the axis of the distillation flask coincide with each other, and the upper edge of the mercury bulb is in the same plane as the lower edge of the welded joint of the side arm.
• 8.8 (source numbering, suspected to be 3.8, requires confirmation against the source standard (source-text extraction)) The distillation flask containing gasoline or solvent naphtha is mounted on the asbestos pad specified as A in GB 515 Figure 7; the distillation flask containing kerosene, jet fuel or light diesel is mounted on the asbestos pad specified as B in GB 515 Figure 7; the distillation flask containing heavy diesel or other heavy oil materials is mounted on the asbestos pad specified as C in GB 515 Figure 7. The side arm of distillation flask 5 is connected to the upper end of condenser tube 1 with a tight cork stopper; the side arm is inserted into the condenser tube to a length of 25~40 millimeters, but must not contact the inner wall of the condenser tube. After applying collodion to the cork stopper connections, place the upper shield 9 on the asbestos pad to cover the distillation flask. Note: when distilling gasoline, neither the heater nor the lower shield temperature should be higher than room temperature.
• 3.9 The graduated cylinder used for measuring the sample does not need to be dried; place it under the condenser tube so that the lower end of the condenser tube is inserted into the graduated cylinder (temporarily not contacting each other) by not less than 25 millimeters, and not lower than the 100 milliliter mark. Plug the mouth of the graduated cylinder with cotton before distillation. When distilling gasoline, the graduated cylinder should be immersed in a tall beaker filled with water, with the beaker liquid level higher than the 100 milliliter mark of the graduated cylinder; a metal weight is pressed on the bottom of the graduated cylinder so that the graduated cylinder cannot float up; during distillation, the water temperature of the tall beaker is maintained at 20±3 ℃ (the source source-text extraction is "203°", requires confirmation against the source standard (source-text extraction)).
• 4.1 After the apparatus is assembled, first record the atmospheric pressure, then begin heating the distillation flask uniformly.
• 4.2 When the first drop of distillate falls from the condenser tube into the graduated cylinder, record the temperature at this time as the initial boiling point.
• 4.3 After distillation reaches the initial boiling point, move the graduated cylinder so that its inner wall contacts the end of the condenser tube, allowing the distillate to flow down along the inner wall of the graduated cylinder. Thereafter the distillation rate is uniform, 4–5 milliliters distillate per minute, generally equivalent to 20–25 drops per 10 seconds. When checking the distillation rate by the corresponding number of drops per 10 seconds, the inner wall of the graduated cylinder may be separated from the end of the condenser tube for a moment. When distilling heavy diesel, the initial 10 milliliters distill at a rate of 2–3 milliliters per minute, and thereafter at 4–5 milliliters per minute.
• 4.4 During the distillation process, record the items required in the technical standard of the sample:
  • 4.4.1 If the technical standard requires the temperature at a distilled percentage (such as 10%, 50%, 90%, etc.), when the volume of distillate in the graduated cylinder reaches the specified percentage, immediately record the distillation temperature. At the end of the test, the thermometer error is corrected according to the correction value in the thermometer verification certificate; the distillation temperature is affected by atmospheric pressure and is corrected according to 4.12.1.
  • 4.4.2 If the technical standard requires the distilled percentage at a certain temperature (such as 100 ℃, 200 ℃, 250 ℃, 270 ℃), when the distillation temperature reaches the specified temperature, immediately record the volume of distillate in the graduated cylinder. At this time, the thermometer error should be corrected in advance according to the correction value in the verification certificate, and the distillation temperature affected by atmospheric pressure should also be corrected in advance according to 4.12.1.
  • Example: When distilling kerosene with a distillation lamp, at atmospheric pressure 96.7 kPa (725 mmHg), the thermometer correction value at 270 ℃ is +1 ℃, that is, use 269 ℃ instead of 270 ℃. When the thermometer reading reaches (270-1)-0.065(101.3-98.7)×7.5 = 267 ℃ [(270-1)-0.065(760-725)=267 ℃]), record the volume of distillate in the graduated cylinder.
• 4.5 During the distillation of gasoline or solvent naphtha, when the distillate in the graduated cylinder reaches 90 mL, a final adjustment of the heating intensity is allowed, requiring the dry point to be reached within 3–5 minutes; if an end point is required but not a dry point, the end point should be reached within 2–4 minutes. The definition of dry point is given in 4.7. During the distillation of jet fuel, kerosene, or light diesel fuel, when the liquid level in the graduated cylinder reaches 95 mL, do not change the heating intensity, and record the time elapsed from 95 mL to the end point; if this time exceeds 3 minutes, the test is invalid.
• 4.6 When distillation reaches the end point specified by the technical standard for the sample (e.g., distillate 95%, 96%, 97.5%, 98%, etc.), in addition to recording the distillation temperature, heating should be stopped at the same time, allow the distillate to flow out for 5 minutes, and record the volume of liquid in the graduated cylinder. When distilling jet fuel or kerosene, if the sample has been evaporated to dryness before reaching the distillate 98% required by the technical standard, a repeat test is allowed to record the distillation temperature and stop heating when the distillate reaches 97.5% (the original text source-text extraction is "$7.5%", requires confirmation against the source standard (source-text extraction)), allow the distillate to flow out for 5 minutes, and then record the volume of liquid in the graduated cylinder; if the volume of liquid in the graduated cylinder is less than 98 mL, the test should be repeated.
• 4.7 If the technical standard for the sample specifies a dry point temperature, heat the distillation flask until the mercury column of the thermometer stops rising and begins to fall, and record the highest temperature indicated by the thermometer as the dry point. After stopping heating, allow the distillate to flow out for 5 minutes, and record the volume of liquid in the graduated cylinder.
• 4.8 During distillation, all readings must be accurate to 0.5 mL and 1 ℃.
• 4.9 At the end of the test, remove the upper cover, allow the distillation flask to cool for 5 minutes, and then remove the distillation flask from the condenser tube. After removing the thermometer and stopper, carefully pour the hot residue in the distillation flask into a 10 mL graduated cylinder. After the graduated cylinder has cooled to 20±3 ℃ (the original text source-text extraction is "203C", requires confirmation against the source standard (source-text extraction)), record the volume of the residue, accurate to 0.1 mL.
• 4.10 The difference obtained by subtracting the total volume of distillate and residue from the 100 mL of sample is the distillation loss.
• 4.11 For samples with unknown distillation range, the following temperatures shall be recorded during the test:
  • 4.11.1 Initial boiling point;
  • 4.11.2 The temperatures at which 10%, 20%, 30%, 40%, 50%, 60%, 70%, 90%, and 97% are distilled.
  • After the approximate grade of the sample is determined, the distillation range determination shall be re-conducted according to the distillation range requirements specified in the technical standard for that grade.
• 4.12 Correction of the effect of atmospheric pressure on distillation temperature:
  • 4.12.1 When the atmospheric pressure is higher than 102.7 kPa (770 mmHg) or lower than 100.0 kPa (750 mmHg), the effect of atmospheric pressure on the distillation temperature shall be calculated according to formula (1) or formula (2) to obtain the correction value C:
    • C = 0.0009(101.3-P)(273+t) ………… (1)
    • C = 0.00012(760-P)(273+t) ………… (2)
    • Where: P— atmospheric pressure during the test, kPa (or mmHg); t— thermometer reading, ℃.
  • Alternatively, the distillation temperature correction constant k from the table may be used to simply calculate the correction value C according to formula (3) or formula (4):
    • C = k(101.3-P)×7.5 ………… (3)
    • C = k(760-P) ………… (4)
  • The data t for distillation temperature at atmospheric pressure P and the data t0 at 101.3 kPa (760 mmHg) have the following conversion relationship:
    • t0 = t + C ………… (5)
    • t = t0 - C ………… (6)
  • 4.12.2 When the actual atmospheric pressure is within the range of 100.0–102.7 kPa (750–770 mmHg), the distillation temperature does not require the above correction, that is, it is considered that t = t0.
• Distillation temperature correction constant table k:
  • 11~20 ℃: 0.035
  • 21~30 ℃: 0.036
  • 31~40 ℃: 0.037
  • 41~50 ℃: 0.038
  • 51~60 ℃: 0.039
  • 61~70 ℃: 0.041
  • 71~80 ℃: 0.042
  • 81~90 ℃: 0.043
  • 91~100 ℃: 0.044
  • 101~110 ℃: 0.045
  • 111~120 ℃: 0.047
  • 121~130 ℃: 0.048
  • 131~140 ℃: 0.049
  • 141~150 ℃: 0.050
  • 151~160 ℃: 0.051
  • 161~170 ℃: 0.053
  • 171~180 ℃: 0.054
  • 181~190 ℃: 0.055
  • 191~200 ℃: 0.056
  • 201~210 ℃: 0.057
  • 211~220 ℃: 0.059
  • 221~230 ℃: 0.060
  • 231~240 ℃: 0.061
  • 241~250 ℃: 0.062
  • 251~260 ℃: 0.063
  • 261~270 ℃: 0.065
  • 271~280 ℃: 0.066
  • 281~290 ℃: 0.067
  • 291~300 ℃: 0.068
  • 301~310 ℃: 0.069
  • 311~320 ℃: 0.071
  • 321~330 ℃: 0.072
  • 331~340 ℃: 0.073
  • 341~350 ℃: 0.074
  • 351~360 ℃: 0.075

9. Qualitative and Quantitative and Calculation Formulas

• Initial boiling point: The temperature recorded when the first drop of distillate falls from the condenser tube into the graduated cylinder.
• Dry point: Heat the distillation flask until the mercury column of the thermometer stops rising and begins to fall, and record the highest temperature indicated by the thermometer.
• End point: When distillation reaches the end point specified by the technical standard for the sample (e.g., distillate 95%, 96%, 97.5%, 98%, etc.), record the distillation temperature.
• Distillation loss: The difference obtained by subtracting the total volume of distillate and residue from the 100 mL of sample.
• Atmospheric pressure correction formulas:
  • C = 0.0009(101.3-P)(273+t) ………… (1)
  • C = 0.00012(760-P)(273+t) ………… (2)
  • C = k(101.3-P)×7.5 ………… (3)
  • C = k(760-P) ………… (4)
  • t0 = t + C ………… (5)
  • t = t0 - C ………… (6)
  • Where: P— atmospheric pressure during the test, kPa (or mmHg); t— thermometer reading, ℃; k— distillation temperature correction constant.
• Correction applicable conditions: Correction is performed when the atmospheric pressure is higher than 102.7 kPa (770 mmHg) or lower than 100.0 kPa (750 mmHg); when the actual atmospheric pressure is within the range of 100.0–102.7 kPa (750–770 mmHg), no correction is required, that is, t = t0.
• Expression of results: The distillation range of the sample is expressed as the arithmetic mean of the repeated determination results specified for each distillation range.

10. Precision

• 5.1 The difference between two repeated determination results shall not exceed the following values:
  • 5.1.1 Initial boiling point is 4 ℃.
  • 5.1.2 Dry point and intermediate distillate are 2 ℃ and 1 mL.
  • 5.1.3 Residue is 0.2 mL.

11. Report

• The distillation range of the sample is expressed as the arithmetic mean of the repeated determination results specified for each distillation range.
• Other reporting requirements: not provided in the available source.

12. Referenced Documents

• GB 515 Technical Conditions for Apparatus for Determination of Distillation Range of Petroleum Products
• GB 514 Technical Conditions for Liquid Thermometers for Petroleum Product Testing

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