GB/T 21452-2008 Determination of particulate matter content in middle distillate fuels — Laboratory filtration method

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Card type: Test method

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

• Standard number: GB/T 21452—2008
• Chinese title: Determination of particulate matter content in middle distillate fuels — Laboratory filtration method
• English title: Petroleum products—Determination of particulate content of middle distillate fuels—Laboratory filtration method
• Adoption relationship: Modified adoption of ISO 15167:1999 (MOD)
• Replacement relationship: This standard is first published (not provided in the available source as replacing other standards)
• Publication/implementation: published on 2008-02-13, implemented on 2008-09-01
• Custodian: National Technical Committee for Standardization of Petroleum Products and Lubricants (SAC/TC 280)
• Drafting organization: Engineering Research Institute of Luoyang Petrochemical Engineering Corporation, Sinopec Group
• Main drafters: Liu Fengyang, Lü Dawei, Wang Yanxing
• Main differences from ISO 15167:1999: referenced standards adopt the corresponding national standards of our country; the wording of repeatability and reproducibility is rewritten according to our country's conventions; Chapter 14 test report is deleted.

2. Scope of application and non-applicability

• 1.1 is applicable to the determination of particulate matter content in middle distillate fuels with a closed-cup flash point not lower than 38 ℃ (determined by GB/T 261).
• 1.1 is not applicable to the determination of light distillate fuels (such as gasoline) or jet fuels.
• 1.2 limits on particulate matter content in middle distillate fuels used for diesel engines and civil use can prevent filter clogging and other operational problems. The determination range of this standard is not greater than 25 g/m³.
• 1.3 The precision of this standard is valid only when the determination is carried out strictly in accordance with the clauses of this standard, especially when the membrane material (see Note to 6.9), sample amount, and complete filtration of the sample all conform to the provisions of this standard.

3. Method principle

• 4 Method summary: A certain volume of sample is filtered through a pre-weighed test filter membrane; after rinsing and drying, the mass increase of the test filter membrane is obtained by weighing, and the mass increase of the control filter membrane located below the test filter membrane can also be obtained. The particulate matter content of the sample is obtained by subtracting the mass increase of the control membrane from the mass increase of the test membrane.
• 3.1 Definition of particulate matter content: under the test conditions of this standard, the amount of substance retained on a filter membrane with a nominal pore size of 0.8 μm, expressed as g/m³.

4. Reagents and materials (purity / preparation)

• 5 General: Unless otherwise specified, analytically pure reagents are used throughout all test procedures. Water shall meet the requirements for grade three water in GB/T 6682.
• 5.1 Isopropanol: chemically pure, filtered through a filter membrane with a pore size of 0.45 μm or smaller before use.
• 5.2 Liquid detergent: water-soluble.
• 5.3 Rinsing liquid: n-heptane or 2,2,4- trimethylpentane. Filter through a filter membrane with a pore size of 0.45 μm or smaller before use.
• 5.4 Tap water: clean, meeting drinking water standards. If suitable water is not available, obtain suitable water by filtration according to 5.3 or use commercially available purified water instead.

5. Apparatus and equipment

• 6.1 Analytical balance: single-pan or double-pan, weighing accuracy of 0.1 mg or higher.
• 6.2 Air ionizer: for use in the balance chamber.
  • Note 1: When using a fixed-pan balance, the air ionizer may be omitted as long as the filter membrane is ensured not to extend beyond the edge of the weighing pan during weighing.
  • Note 2: The air ionizer should be used within one year of manufacture.
• 6.3 Oven: explosion-proof type, air circulation fan should not be used, temperature controllable at 90 ℃±5 ℃.
• 6.4 Petri dish: diameter about 125 mm, with a movable glass support inside for supporting the filter membrane.
  • Note: A watch-glass-sized glass dish is suitable as a support for the filter membrane.
• 6.5 Tweezers: stainless steel, flat tips, without serrations.
• 6.6 Laboratory clamps: made of stainless steel or other suitable corrosion-resistant material, used to close container lids.
• 6.7 Vacuum system: capable of maintaining an absolute pressure of 1 kPa–100 kPa (the source text source-text extraction is "[unreadable character].1KPa–100 kPa", requires confirmation against the source standard (source-text extraction)).
• 6.8 Test filter membrane: flat, diameter at least (the source text source-text extraction is missing, requires confirmation against the source standard (source-text extraction)); nominal pore size of 0.8 μm, material is nylon or cellulose ester (see Note to 6.9).
• 6.9 Control filter membrane: diameter 17 mm (the source text source-text extraction is "17/mr", requires confirmation against the source standard (source-text extraction)), nominal pore size of 0.8 μm, material is nylon or cellulose ester, flat or grid form.
  • Note: The precision of this standard was obtained using only nylon membranes (the source text source-text extraction is "[garbled wording about precision and nylon membranes]", requires confirmation against the source standard (source-text extraction)).
• 6.10 Rinsing liquid dispenser: usually equipped with a filter membrane with a nominal pore size of 0.15 μm or smaller, as shown in Figure 1.
  • Note: If the rinsing liquid is pre-filtered through a filter membrane with a nominal pore size of 0.15 μm or smaller, and measures are taken to ensure good cleanliness inside the rinsing liquid bottle, a standard laboratory rinsing liquid bottle may also be used.
  • Figure 1 Rinsing liquid filtration and dispensing apparatus: 1— reagent-resistant plastic tubing; 2— support plate; 3— membrane, 0.45 μm; 4— solvent filtration dispenser.
• 6.11 Filtration apparatus: as shown in Figure 2.
  • 6.11.1 Filtration funnel: composed of a funnel and a funnel support plate that supports the filter membrane; the filter membrane is fixed between the sealing surface of the funnel and the funnel support plate by a locking ring or elastic clamp.
  • 6.11.2 Receiving flask: borosilicate glass, capacity 1 L, preferably graduated, used to receive the filtered sample and the rinsing liquid during rinsing (see 10.1 and 10.10). The side tube of the receiving flask is connected to a buffer flask (6.11.3), and through the buffer flask to the vacuum system; assemble as shown in Figure 2 during use, so as to prevent the flask from breaking.
    • Note: The flask may be wrapped with dense, strong plastic mesh or tape to prevent glass fragments from scattering everywhere if the flask breaks.
  • 6.11.3 Buffer flask: minimum capacity 600 mL, borosilicate glass. The side tube is connected to the receiving flask (6.11.2); protect it carefully to prevent the flask from breaking.
  • 6.11.4 Ground wire: diameter 0.912 mm~2.59 mm (requires confirmation against the source standard (source-text extraction)), flexible stainless steel or copper wire. As shown in Figure 2, connected to the flask and grounded.
  • Figure 2 Apparatus for determination of particulate matter content: 1— vacuum tube; 2— funnel; 3— clamp; 4— ground wire; 5— receiving flask; 6— buffer flask; 7— laboratory clamp; 8— to vacuum system; 9— use suitable sealing material to ensure good sealing among the tube, clamp, and ground wire; 10— the clamp jaws and handle, the ground wire is connected to the exposed metal part of the handle.
• 6.12 Plastic film: polyethylene film or other clean film resistant to reagents and samples.
  • Note: Clean aluminum foil may also be used.
• 6.13 Graduated cylinder: borosilicate glass, capacity 100 mL~500 mL.

6. Recommended operating conditions

• Oven temperature: 90 ℃±5 ℃ (6.3).
• Drying time: 30 min (9.5).
• Equilibration time in the balance room: 30 min (9.6).
• Weighing accuracy: 0.1 mg (6.1, 9.7).
• Shaking time: 30 s±5 s (10.3).
• Determination of filtration stop: 100 mL sample exceeding 10 min before filtration can be completed is regarded as slow (10.9).
• Continuation of vacuum: after washing is completed, 10 s~15 s or until all rinsing liquid is removed from the filter membrane (10.10.2).
• Absolute pressure of vacuum system: 1 kPa~100 kPa (6.7, requires confirmation against the source standard (source-text extraction)).

7. Sampling and sample preparation

• 8.1 During sampling, ensure that the sampling equipment is cleaned in accordance with Chapter 7. As far as possible, the sampling point and the specified sampling equipment should have the same cleanliness, and contamination of the sample by the external environment should be avoided as much as possible.
• 8.2 Only sample containers with a capacity of 1 L±0.15 L are used.
• 8.3 Sampling containers may be glass bottles, or containers lined with epoxy resin, polytetrafluoroethylene, or colorless high-density polyethylene material. The advantage of using colorless glass containers is that it is easy to see clearly whether the inside of the container is clean. However, transparent glass containers exposed to ultraviolet light have the risk of generating particulate matter. If transparent glass containers are used, avoid exposing the sample to ultraviolet light as much as possible.
• 8.4 The sample should be filled to 85%~95% of the container capacity.
• 8.5 Sample in accordance with GB/T 4756; the sample is preferably taken dynamically from the product distribution line or the sampling port of an on-site sampling device. Before sampling, ensure that the sampling line has been flushed with the sample to be tested.
• 8.6 When sampling from a fixed storage tank in accordance with the requirements of GB/T 4756, ensure that the sample is not passed through other containers but is directly loaded into a pre-prepared container.
  • Note: When sampling from a fixed storage tank, particulate matter in the fuel is likely to settle, resulting in low determination results. If possible, circulate or stir the components in the tank before sampling, or sample immediately before canning.
• 7 Preparation of sample containers and instruments:
  • 7.1 Thoroughly clean the sample container (remove all markings, labels, etc.), sampler, and all surfaces of instrument parts that may come into contact with the sample or rinsing liquid or may carry impurities onto the filter membrane, in accordance with the requirements of 7.2~7.7.
  • 7.2 Wash with hot tap water (5.4) containing detergent (5.2).
  • 7.3 Rinse thoroughly with hot tap water.
  • 7.4 During this process and the subsequent cleaning, use clean laboratory clamps (6.6) to hold the outer surface of the container lid and rinse thoroughly with water.
  • 7.5 Rinse thoroughly with isopropanol (5.1).
  • 7.6 Rinse thoroughly with flushing liquid (5.3).
  • 7.7 Cover the top of the sample container and the opening of the funnel connected to the filtration apparatus with a plastic film (6.12) that has been pre-rinsed (rinsed with flushing liquid) clean and air-dried.
• 9 Preparation of filter membranes:
  • 9.1 Prepare at least two sets of filter membranes for each test; each set includes a test filter membrane (6.8) and a control filter membrane (6.9).
  • 9.2 Mark the petri dish (6.4) to distinguish the membranes.
  • 9.3 Ensure that all glassware has been cleaned as specified in Chapter 7.
  • 9.4 Using tweezers (6.5), place the test filter membrane (6.8) and the control filter membrane (6.9) side by side on the glass support in the petri dish.
  • 9.5 Slightly open the lid of the petri dish and place it in the oven (6.3) to dry for 30 min.
  • 9.6 Remove each petri dish from the oven and place it near the balance (6.1), keeping the lid slightly open but protecting the filter membranes from air contamination. Allow to stand for 30 min so that the membranes reach the same temperature and humidity as the room.
  • 9.7 Using tweezers (6.5), grip the edge of the control filter membrane, remove the control filter membrane from the petri dish, place it in the center of the balance weighing pan, weigh to the nearest 0.1 mg, and record the mass. Then return the weighed control filter membrane to the petri dish.
  • 9.8 Weigh the mass of the test membrane in the same manner as in 9.7.
  • 9.9 Using clean tweezers (6.5), grip the edge of the filter membrane, place the weighed control filter membrane on the membrane support plate of the filtration apparatus (see Figure 2), then place the weighed test filter membrane on top of the control filter membrane, and then secure the membranes by clamping the upper and lower parts of the funnel with a locking ring or elastic clip as shown in Figure 2. Do not remove the plastic film from the funnel opening before filtration begins.

8. Analytical procedure

• 10.1 All contents of the sample container shall be processed according to the analytical procedure of this standard. Therefore, it is necessary to place the container holding the filtered sample separately from containers holding any other materials (such as flushing liquid). Prepare clean, correctly labeled sample containers for use in rapidly transferring the filtered sample, so that changes in other properties of the sample caused by contamination can be minimized.
• 10.2 First, thoroughly wash the outer surface of the top area of the sample container with hot water (5.4) containing detergent (5.2), then wash with tap water, and then wash with isopropanol (5.1). Discard the waste liquid after rinsing.
• 10.3 Shake the sample container vigorously for 30 s±5 s.
• 10.4 Open the lid of the sample container, rinse off any dirt on the inner sealing surface of the lid with flushing liquid (5.3), ensuring that the flushing liquid does not enter the sample container. Collect the flushing liquid in a clean, dry container and cover it with plastic film (6.12).
• 10.5 Install the filtration apparatus as shown in Figure 2 and place it in a fume hood.
• 10.6 Pour the sample from the sample container into a graduated cylinder (6.13) of 500 mL, record the sample volume, apply vacuum, and pour the sample in steps into the filtration funnel for filtration.
  • Note: Most samples can be filtered quickly. However, some samples may clog the filter membrane during filtration due to the amount and/or nature of particulate matter. If the filtration rate is very slow, it is recommended to use a graduated cylinder of 100 mL.
• 10.7 If the sample poured into the filtration funnel for the first time filters quickly, repeat 10.6 until all sample in the sample container has been filtered, and measure the volume of the filtered sample.
• 10.8 Remove the receiving flask and quickly transfer the filtered sample into a clean, dry container (10.1).
• 10.9 If the filtration rate is so slow that 100 mL of sample requires more than 10 min to complete filtration, record the volume of filtered sample, perform the operation according to 10.8 and then according to 10.10. Install the second set of filter membranes on the filtration apparatus as described in 9.9, and repeat 10.6 and 10.7. Repeat as many times as necessary.
  • Note: If the filtration rate is very slow (Note 10.6), it is recommended to reduce the amount of sample poured into the filtration funnel each time, so as to minimize the amount of liquid retained on the filter membrane when filtration is clogged.
• 10.10 If the sample in the filtration funnel completely stops flowing while liquid still remains on the filter membrane, proceed according to 10.10.1. If the liquid flow rate is slower than required by 10.9, but the liquid on the filter membrane has been completely filtered, proceed according to 10.10.2.
  • 10.10.1 Disconnect the receiving flask from the vacuum system, carefully remove the filtration funnel while keeping it vertical. Replace the first set of funnels on the receiving flask with a second set (or more) of assembled funnels containing a pair of weighed filter membranes. Carefully pour the liquid on the filter membrane in the first set of funnels into the second set of funnels. Reconnect the vacuum system and continue filtration. Install the first set of filtration funnels on another receiving flask and proceed according to 10.10.2.
  • 10.10.2 Replace the original receiving flask with another receiving flask (which need not have the same standard of cleanliness), and thoroughly rinse the inner wall of the funnel and the surface connected to the filter membrane support plate with flushing liquid. Continue applying vacuum, carefully remove the upper part of the funnel, and rinse the edge of the filter membrane from the edge inward with a gentle stream of flushing liquid, taking care not to wash away particulate matter on the surface of the filter membrane. Continue applying vacuum until after washing is completed for 10 s–15 s or until all flushing liquid is removed from the filter membrane. Using clean tweezers (6.5), carefully remove the test filter membrane and control filter membrane from the filter membrane support plate, place them in a clean petri dish, and dry and weigh according to 9.5–9.7. Take care not to disturb particulate matter on the surface of the test filter membrane.
• 10.11 After all contents of the sample container have been filtered, record the volume of the filtered sample, replace the original receiving flask with another receiving flask (which need not have the same standard of cleanliness), and thoroughly rinse the sample container and graduated cylinder with flushing liquid (5.3). Rinse each container 3 times, using 25 mL each time, ensuring that particulate matter in the containers is washed away; pour the flushing liquid through the filtration funnel. The flushing liquid obtained in 10.1 shall also pass through the filtration funnel, and rinse that container with a portion of 25 mL flushing liquid, which shall also pass through the filtration funnel. Dismantle the apparatus and pour out the wash liquid. Dry and weigh according to 10.10.2.

9. Qualitative and quantitative determination and calculation formulas

• 11 Calculation: Calculate the particulate matter content P (g/m³) in the sample according to formula (1).
  • P = [(m₂ − m₁) − (m₄ − m₃)] / V × 100 ……(1)
  • Where:
    • m₁—the numerical value of the mass of the test filter membrane before sample filtration, in grams (g);
    • m₂—the numerical value of the mass of the test filter membrane after sample filtration, in grams (g);
    • m₃—the numerical value of the mass of the control membrane before sample filtration, in grams (g);
    • m₄—the numerical value of the mass of the control filter membrane after sample filtration, in grams (g);
    • V— the numerical value of the total volume of filtered sample, in milliliters (mL).
  • Note: The original formula source-text extraction is “P=Smna-m)(m, one ma2 ×100”; the formula structure has been arranged according to the context and the general form of ISO 15167, requires confirmation against the source standard (source-text extraction).
• 12 Expression of results: Report the particulate matter content of the sample (g/m³), accurate to 0.1 g/m³. At the same time, also report the total volume of filtered sample during the test (mL). If more than one set of filter membranes is used, also indicate the number of sets of filter membranes used in parentheses.
  • The report format is: particulate matter content (g/m³)/total volume of filtered sample (mL) (number of membrane sets)
  • Example: 14.2/985 (3)

10. Precision

• 13.1 General: The precision of this standard is determined by statistical analysis of interlaboratory test results and is expressed as follows (confidence level of 95%).
• 13.2 Repeatability (r): The difference between two results obtained by the same operator, in the same laboratory, using the same apparatus, following the procedure specified in the method, on the same sample shall not exceed the value calculated by formula (2). Typical repeatability values are shown in Table 1.
  • r = 0.6894 X^0.5 ……(2)
  • Where: X— the average of the two results.
• 13.3 Reproducibility (R): The difference between two independent test results obtained by different operators, in different laboratories, following the procedure specified in the method, on the same sample shall not exceed the value calculated by formula (3). Typical reproducibility values are shown in Table 1.
  • R = 1.133 X^0.5 ……(3)
  • Where: X— the average of the two results.
• Table 1 Typical precision values (in grams per cubic meter):

11. Report

• 12 Expression of results: Report the particulate matter content of the sample (g/m³), accurate to 0.1 g/m³. At the same time, also report the total volume of filtered sample during the test (mL). If more than one set of filter membranes is used, also indicate the number of sets of filter membranes used in parentheses.
• Report format: particulate matter content (g/m³)/total volume of filtered sample (mL) (number of membrane sets)
• Example: 14.2/985 (3)
• Note: When this standard was modified and adopted from ISO 15167:1999, Chapter 14 test report was deleted; the reporting requirements shall be governed by Chapter 12 of this standard.

12. Referenced documents

• GB/T 261 Petroleum products—Determination of flash point—Closed cup method (GB/T 261—1983, eqv ISO 2719:1973)
• GB/T 4756 Petroleum liquids—Manual sampling (GB/T 4756—1998, eqv ISO 3170:1988)
• GB/T 6682 Water for analytical laboratory use—Specification and test methods (GB/T 6682—1992, neq ISO 3696:1987)
• Note: In the original text, 8.5 contains “IGB/T 1756”, requires confirmation against the source standard (source-text extraction), and according to the context should be GB/T 4756.

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