⛽ Total contamination in diesel fuel

Petrochemistry PN-EN 12662

Overview

Total contamination in diesel fuel is the total content of solid particles insoluble in the fuel, expressed in mg/kg. This parameter is crucial for the proper operation of injection systems in high-pressure diesel engines, especially modern common rail systems, where tolerances between working elements of injectors are on the order of a few micrometers.

The PN-EN 12662 standard defines a method of filtering a fuel sample (800 mL) through a pre-weighed filter membrane with 0.8 µm porosity. After filtration, the membrane is rinsed with heptane to remove residual oil, dried, and weighed again. The difference in membrane mass represents the contamination content. The method is applicable to middle distillates, diesel fuels with up to 30% (V/V) FAME addition, and pure methyl esters.

Quality requirements for diesel fuel according to PN-EN 590 specify a maximum total contamination level of 24 mg/kg. Exceeding this value can lead to clogging of fuel filters, accelerated wear of pumps and injectors, and failure of the engine fuel supply system. In the era of biofuel components (B7, B10, B20), monitoring this parameter is especially important because FAME tends to form deposits and increase contamination.

The working range of the method is from 12 to 26 mg/kg, established based on international studies according to EN ISO 4259-1. The method is applicable to products with kinematic viscosity not exceeding 8 mm²/s at 20°C or 5 mm²/s at 40°C.

Method principle

The method consists of filtering a measured volume of fuel sample (800 mL) through a previously dried and weighed filter membrane with nominal porosity of 0.8 µm, using vacuum created by a vacuum pump. Insoluble matter is retained on the membrane surface. After filtration is complete, the membrane is rinsed with solvent (heptane) to remove adsorbed oil, then dried in an oven and weighed on an analytical balance. The difference in membrane mass before and after filtration, related to the mass of the filtered sample, constitutes the result of total contamination determination expressed in mg/kg.

Applications

• Quality control of diesel fuel according to PN-EN 590 (max 24 mg/kg)
• Testing fuels with FAME biocomponents (B7, B10, B20, B100)
• Monitoring fuel purity in the logistics chain (refinery-terminal-station)
• Control of storage impact on fuel quality
• Evaluation of filtration system efficiency in fuel installations
• Quality complaints and commercial disputes regarding fuels
• Type testing and homologation testing of fuels

Key parameters

Standard

Standard number

PN-EN 12662:2014

Title (PL)

Ciekle przetwory naftowe — Oznaczanie zanieczyszczenia ogolnego destylatow srednich, olejow napedowych i estrow metylowych kwasow tluszczowych

Title (EN)

Liquid petroleum products — Determination of total contamination in middle distillates, diesel fuels and fatty acid methyl esters

Step-by-step procedure

1. Membrane preparation

   Rinse membrane with heptane, dry in oven (105°C, 30 min), cool in desiccator to room temperature. Weigh with 0.1 mg accuracy.

   ⏱ Time: 45 min • 🌡 Temperature: 105°C

2. Assembly of filtration set

   Place membrane on fritted funnel, attach funnel to suction flask. Connect vacuum pump. Check connections for leaks.

3. Sample preparation

   Thoroughly mix fuel sample by inverting container. Measure 800 mL with graduated cylinder.

   ⏱ Time: 5 min

4. Sample filtration

   Turn on vacuum pump. Slowly pour sample onto membrane, maintaining constant liquid level above membrane. Filter entire 800 mL.

   ⏱ Time: 15–30 min

5. Membrane rinsing

   After filtering entire sample, rinse membrane 3 × 20 mL with heptane to remove adsorbed oil. Continue suction until solvent is removed.

   ⏱ Time: 5 min

6. Membrane drying

   Remove membrane from funnel with tweezers, place in oven (105°C, 30 min). Cool in desiccator to room temperature (min. 30 min).

   ⏱ Time: 60 min • 🌡 Temperature: 105°C

7. Membrane weighing

   Weigh membrane on analytical balance with 0.1 mg accuracy. Record final mass.

   ⏱ Time: 5 min

8. Result calculation

   Contamination [mg/kg] = (m2 - m1) × 1000 / (V × d), where m2 = final mass, m1 = initial mass of membrane [mg], V = sample volume [mL], d = sample density [g/mL].

   ⏱ Time: 5 min

9. Quality control

   Perform blank test (filtration of heptane through membrane). Membrane mass difference should not exceed 0.3 mg.

   ⏱ Time: 60 min

10. Recording and reporting

    Record result in mg/kg with accuracy to 1 mg/kg. Compare with PN-EN 590 limit (max 24 mg/kg). Include data on sample temperature and density.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• n-Heptane — flammable (R11), use away from ignition sources, work under fume hood
• Toluene — toxic by inhalation (R20), use only under fume hood
• Acetone — flammable, may cause eye irritation
• Diesel fuel — harmful, avoid skin contact, use nitrile gloves
• Vacuum pump — risk of solvent vapor explosion, ensure ventilation

Frequently asked questions