ULSD (Ultra Low Sulfur Diesel) Sulfur Analysis

According to the ISO 13032 standard test method, the analysis of sulfur in ultra-low sulfur diesel is demonstrated. Regulations around the world have limited the amount of sulfur in a number of fuel oils with particular attention to diesel fuel. For several years, on-road diesel has been restricted to a maximum sulfur concentration between 10 and 15 ppm, based on the global region.

Now, these restrictions are extended to all diesel fuels, including use in off-road diesel engines and large engines. Ultra-low sulfur on-road diesel fuel (15 ppm sulfur or less) was used in all on-road diesel vehicles and engines of model years 2007 and later. It is recommended to be used in all vehicles and diesel engines. Based on the ISO 13032 standard test method, sulfur analysis in ultra low sulfur diesel is used.

Instrumentation

Model: Rigaku NEX QC+
X-ray tube: 4W Ag-anode SDD
Typical sample: diesel fuel
Movie: Prolene
Analysis time: 300 seconds
Environment: Helium
Example of a ring: Single position 32mm

Figure 1.

International standard test method

The Rigaku NEX QC+ Complies with ISO 13032 for the measurement of ultra-low sulfur content between 8 and 50 mg / kg in diesel fuels and gasoline, as described in the scope of ISO 13032 method.

Sample preparation

For sample measurement, gently shake the sample vial, allow the bubbles to settle and fill a 32 mm XRF sample cup with 5 g of sample.

Calibration

Empirical calibration was performed using a series of 6 certified diesel calibration standards as shown in Table 1

Table 1.

Elements
Units: ppm
RMS deviation: 0.76
Correlation: 0.99170
Sample ID Standard value Calculated value
STD 1 5.0 5.2
STANDARD 2 10.0 10.1
STANDARD 3 15.0 14.0
STANDARD 4 20.0 20.9
STANDARD 5 25.0 24.9
STANDARD 6 50.0 49.4

Figure 2.

Precision

The repeatability of the instrument (precision) is determined by ten repeated analyzes of a sample in a static position using an analysis time of 300 seconds.

Table 2.

Item: S Units: ppm
Sample Standard value Average value Standard dev % relative
STANDARD 2 10.0 10.2 0.48 4.8
STANDARD 6 50.0 50.9 0.50 1.0

Limit of detection

Ten repeated analyzes of a sample of virgin sulfur-free diesel are performed with the static sample and the standard deviation is determined. The lower limit of detection (LLD) is then defined as three times the standard deviation. The following typical LLDs are reported here using a scan time of 300 s.

Table 3.

Element LLD Analysis time
S 1.3 ppm 300 seconds
S 1.9 ppm 600 seconds

Note: 1 ppm = 1 mg / kg

Conclusion

The results shown here indicate that the Rigaku NEX QC+ The EDXRF analyzer offers excellent performance for measuring ULSD according to the ISO 13032 standard test method. The versatility of the NEX QC+ also makes it a suitable tool for measuring many other oil elements and matrices, such as lubricating oils, wear metals in oils, used oils and used oils, and other elemental analysis needs throughout the oil industry.

This information was obtained, reviewed and adapted from documents provided by Rigaku.

For more information on this source, please visit Rigaku.


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Jenny T. Curlee

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