NB/SH/T 0509-2010 Test method for separation of asphalt into four fractions

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.

Source limitations: The pore-volume unit, filter-paper size, circulating-water temperature, hot n-heptane temperature and alumina-activation wording require verification. Some precision-table values and their fraction assignments are missing or unclear. The available card specifies branches above and below 10% asphaltenes but does not specify the branch for exactly 10%; this gap remains unresolved.

Card type: Test method

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

• Standard number: NB/SH/T 0509-2010
• Chinese title, translated: Determination of four fractions in petroleum asphalt
• English name: Test method for separation of asphalt into four fractions
• Replacement relationship: replaces SH/T 0509-1992.
• Adoption: non-equivalent adoption of JPI-SS-22-83 (confirmed in 1998).
• Publication / implementation: published 2010-05-01; implemented 2010-10-01.
• Issuing authority: National Energy Administration.
• Previous editions: SH/T 0509-1992 (1998).

2. Scope of application and exclusions

• 1.1 This standard specifies a method for determining the four fractions of petroleum asphalt: saturates, aromatics, resins and asphaltenes.
• 1.2 This standard applies to petroleum asphalt; it may also be used as a reference for residual oils.
• 1.3 This standard does not address the safety requirements associated with its use. Users are responsible for establishing appropriate safe operating procedures before use.

3. Principle

Precipitate the asphaltenes from the sample with n-heptane and filter. Reflux with n-heptane to remove soluble material entrained in the precipitate, then dissolve the precipitate by refluxing with toluene to obtain the asphaltenes. Adsorb the deasphalted fraction on an alumina chromatography column and elute successively with n-heptane (or petroleum ether), toluene and toluene–ethanol to obtain saturates, aromatics and resins, respectively.

4. Reagents and materials (purity / preparation)

• 4.2.1 n-Heptane: analytical reagent grade, dearomatized (passes the sulfuric acid–formaldehyde test).
• 4.2.2 Petroleum ether: analytical reagent grade, 60℃–90℃, dearomatized (passes the sulfuric acid–formaldehyde test).
• 4.2.3 Toluene: chemically pure.
• 4.2.4 95% ethanol: chemically pure.
• 4.2.5 Alumina: neutral, chromatography grade, 100–200 mesh, specific surface area >150 m²/g, pore volume 0.23 cm²/g–0.27 cm²/g (requires confirmation against the source standard: the pore-volume unit may be cm³/g). Activate before use.
• 4.2.6 Quantitative filter paper: medium speed, φ11.96 cm (requires confirmation against the source standard: the extracted text is "[unreadable character]11.96m").
• 5.1 Alumina activation: activate the alumina in a muffle furnace at 500℃ for 6h. Remove and immediately place it in a desiccator fitted with a stopcock and containing no desiccant. After cooling, transfer it into a previously weighed, stoppered narrow-mouth bottle. Add distilled water equal to 1% of the net alumina mass, stopper tightly, shake vigorously and leave for 24h before use. The storage life is 1 week. Unused activated alumina may be reactivated before use. (The extracted wording in this paragraph is garbled and requires confirmation against the source standard.)

5. Apparatus

• 4.1.1 Asphaltene determination apparatus: see Figure 1, comprising a ground-glass-jointed Erlenmeyer flask, an extractor and a condenser.
• 4.1.2 Electric heating mantle.
• 4.1.3 Short-stem glass funnel: φ75mm–90mm.
• 4.1.4 Funnel stand.
• 4.1.5 Glass adsorption column: see Figure 2; externally jacketed for temperature control using circulating hot water.
• 4.1.6 Precision constant-temperature water bath.
• 4.1.7 Muffle furnace: 0℃–800℃.
• 4.1.8 Vacuum oven: capable of maintaining 105℃–110℃ and a vacuum level of 93kPa±1kPa (700mmHg±10mmHg).
• 4.1.9 Ground-glass-jointed Erlenmeyer flasks: size 24 joint, 150mL–250mL.
• 4.1.10 Desiccators: fitted with a stopcock, capacity 3000mL, without desiccant; and capacity 3000mL–5000mL, with desiccant.
• 4.1.11 Analytical balance: weighing to the nearest 0.0001g.
• 4.1.12 Graduated cylinders: 20mL, 50mL and 100mL.

6. Recommended operating conditions

• 6.3.2 Adsorption-column circulating-water temperature: 5℃–10℃ (requires confirmation against the source standard: the extracted text is "5–:1°").
• 6.3.5 Elution flow rate: 2mL/min–3mL/min.
• 6.2.6 / 6.3.6 Vacuum-oven drying conditions: temperature 105℃–110℃, vacuum level 93kPa±1kPa (700mmHg±10mmHg), held for 1h.
• 6.2.2 Reflux conditions: heat samples with an asphaltene content below 10% under reflux for 0.5h. For samples above 10%, the reflux time may be extended to 1h. Control the condensate return so that it falls as drops rather than a continuous stream.
• 6.2.3 Temperature of hot n-heptane used for washing: 60℃–70℃ (requires confirmation against the source standard: the extracted text is "00/C[unreadable separator]70C").
• 5.1 Alumina activation temperature: 500℃, for 6h.

7. Sampling and sample preparation

• Refer to GB/T 11147, Sampling of asphalt.
• 6.2.1 Into a ground-glass-jointed Erlenmeyer flask previously brought to constant mass, weigh 1g±0.1g of sample (for asphaltene content below 10%), or 0.5g±0.01g (for asphaltene content above 10%), to the nearest 0.0001g. Add n-heptane at 50mL per gram of sample.
• 6.3.1 For samples with asphaltene content below 10%, directly weigh 0.5g±0.01g of sample to the nearest 0.0001g and dissolve and dilute with n-heptane.

8. Procedure

• 6.1 See Figure 3 for the analytical flow chart. For samples with asphaltene content greater than 10%, separate the asphaltenes by n-heptane precipitation and determine the other three fractions in the soluble portion by elution chromatography. For samples with asphaltene content less than 10%, two portions may be weighed: one for asphaltenes and the other for direct determination of saturates and aromatics; resins are obtained by difference.
• 6.2 Determination of asphaltene content:
  • 6.2.1 Weigh the sample and add n-heptane (see section 7).
  • 6.2.2 Connect the ground-glass-jointed flask containing the sample and n-heptane (flask 1) to the condenser and heat under reflux (see section 6 for the duration). After the solution has cooled, remove flask 1, stopper it and leave it in the dark to settle.
  • 6.2.3 Without shaking, slowly decant as much clear supernatant as possible into a funnel containing quantitative filter paper. Finally, shake the remaining small volume of solution with the precipitate and pour onto the filter paper. Do not let the liquid rise to the upper edge of the paper. Wash the residue in flask 1 in several portions using a total of 30mL of n-heptane heated to 60℃–70℃, also pouring the washes onto the filter paper. Collect all filtrate in flask 2. Flask 1 need not be cleaned; retain it for 6.2.5.
  • 6.2.4 Fold the filter paper containing the precipitate and place it in the extractor. Assemble flask 2, the extractor and condenser as shown in Figure 1. Heat under reflux for 1h or until the liquid dripping down is colorless. After reflux, allow to cool slightly, remove flask 2 and proceed as described in 6.3.1.
  • 6.2.5 Add 60mL of toluene to flask 1, fit the extractor and condenser used in 6.2.4, and reflux for at least 1h or extract until the droplets are colorless.
  • 6.2.6 After cooling, remove flask 1 and distil off the toluene. Place the flask in the vacuum oven at 105℃–110℃ and a vacuum level of 93kPa±1kPa (700mmHg±10mmHg) for 1h. Remove, cool to room temperature in a desiccator containing desiccant, and weigh the asphaltenes obtained, m₁, to the nearest 0.0001g.
• 6.3 Determination of saturates, aromatics and resins (or resins plus asphaltenes):
  • 6.3.1 For samples with asphaltene content above 10%, recover most of the n-heptane from flask 2, concentrating the solution to approximately 10mL for loading onto the elution chromatography column, and proceed according to 6.3.2. For samples below 10%, directly weigh 0.5g±0.01g of sample to the nearest 0.0001g and dissolve and dilute with n-heptane.
  • 6.3.2 Connect the adsorption column to the precision constant-temperature water bath as shown in Figure 2 and maintain the circulating-water temperature at 5℃–10℃.
  • 6.3.3 Place a small plug of absorbent cotton at the bottom of the clean, dry adsorption column. Add 40g of prepared alumina from the top while tapping the column gently with a rubber-covered thin rod to pack it uniformly and firmly. Immediately add 30mL of n-heptane to prewet the column.
  • 6.3.4 When all the prewetting n-heptane has entered the top of the alumina bed, immediately add the concentrated solution (or dissolved and diluted sample) from 6.3.1. Use 10mL of n-heptane, taken from the 80mL allocated to eluting the saturates, in several portions to wash the flask residue onto the column. Place a graduated cylinder below the column to collect the n-heptane emerging first. As soon as the whole sample enters the top of the alumina bed, cover it with a little additional prepared alumina.
  • 6.3.5 Add the solvents from Table 1 in sequence for elution. A double rubber bulb may be used to apply pressure and control the flow rate, but the initial flow should not be too fast so that adsorption is complete; pressure is generally adjusted only after collection of the aromatic fraction. Maintain 2mL/min–3mL/min throughout. The first 20mL of eluate is pure n-heptane and may be recycled as part of the 80mL in Table 1. Subsequently use ground-glass-jointed Erlenmeyer flasks previously brought to constant mass as receivers. Change the eluent and receiver when all of the preceding solvent has entered the top of the alumina bed. Fractions desorbed with toluene–ethanol may be collected in the same flask 5. Record the flask numbers in order.
  • 6.3.6 After recovering the solvent from each collected fraction, place the flasks in the vacuum oven at 105℃–110℃ and a vacuum level of 93kPa±1kPa (700mmHg±10mmHg) for 1h. Remove, cool to room temperature in a desiccator containing desiccant and weigh to the nearest 0.0001g, obtaining the masses of saturates m₂, aromatics m₃ and resins m₄ (or resins plus asphaltenes m₅). Because small amounts of toluene-insoluble material are not measured and small amounts of resins (or resins plus asphaltenes) cannot be completely desorbed, the total recovery is generally 90%–97%. The resin (or resin-plus-asphaltene) content may be calculated by difference.

Table 1 Elution solvents and fractions obtained

*Dearomatized petroleum ether may replace n-heptane for elution of saturates, but n-heptane must be used in referee tests.

9. Qualitative and quantitative determination and calculation

• 7.1 Calculate the asphaltene content X_A using equation (1): X_A = m₁ / m × 100 where m₁ is the mass of asphaltenes in the sample, g, and m is the mass of the asphalt sample, g.
• 7.2 Calculate the saturate content X_S using equation (2): X_S = m₂ / m × 100 where m₂ is the mass of saturates in the sample, g.
• 7.3 Calculate the aromatic content X_Ar using equation (3): X_Ar = m₃ / m × 100 where m₃ is the mass of aromatics in the sample, g.
• 7.4 There are two methods for determining the resin content:
  • 7.4.1 Difference method: calculate the resin mass fraction X_R using equation (4): X_R = 100 - X_S - X_A - X_Ar
  • 7.4.2 Elution method: calculate the resin content X_R using equation (5) or (6):
    • For a sample asphaltene content >10%, use equation (5): X_R = m₄ / m × 100 where m₄ is the mass of resins in the sample, g.
    • For a sample asphaltene content <10%, use equation (6): X_R = [(m₅ - m₁) / m] × 100 where m₅ is the mass of resins plus asphaltenes in the sample, g.

10. Precision

Apply the following limits to results expressed as percentages (95% confidence level).

• 9.1 Repeatability: the difference between two results obtained by the same operator on the same sample should not exceed the values in Table 2.
• 9.2 Reproducibility: the difference between two results obtained by different operators on the same sample should not exceed the values in Table 2.

Table 2 Method precision

(The fraction names corresponding to the determination ranges and some reproducibility values in Table 2 are garbled in the available source and require confirmation against the source standard. The words aromatics, resins and asphaltenes can be identified.)

11. Report

Report the arithmetic mean of two replicate results for a sample. For resins, state the determination method used.

12. Referenced documents

• GB/T 514 Specification for liquid-in-glass thermometers for testing petroleum products.
• GB/T 11147 Sampling of asphalt.
• SH/T 0652 Terminology relating to petroleum asphalt.

13. Source uncertainties requiring verification

• Items requiring confirmation against the source standard: the pore-volume unit in 4.2.5; filter-paper dimensions in 4.2.6; circulating-water temperature in 6.3.2; hot n-heptane temperature in 6.2.3; wording of the alumina-activation paragraph in 5.1; and some precision values and their associated fractions in Table 2.

14. Quick reference questions and answers