Environmental and economic concerns are pushing the need for fuel-efficient engines. One of the ways that engine manufacturers are getting more power from a given amount of fuel is by designing the engine to run a high compression. This means that fuel is ‘squeezed’ more by the piston at the point of ignition. At least, that’s the theory. In practice, if the fuel has a low octane rating it will ignite before the maximum level of compression is reached and you won’t get the improved efficiency the engine was designed for. Instead you’ll get unwanted combustion within the engine that can be heard as a distinct ‘knocking’ sound and can cause engine damage. Therefore, high efficiency engines need a high octane fuel.
Historically, tetraethyl lead (TEL) was added to fuel to boost the octane rating. However, this was phased out in the 1990s when it was discovered that leaded fuel caused air pollution that adversely affected human health. Today, methylcyclopentadiethyl manganese tricarbonyl, or MMT, has largely replaced TEL as an octane boosting additive.
We talk about the manganese content in fuel rather than the MMT content, because the level of manganese (Mn) is what we test for. Currently, the ASTM test method for measuring the level of manganese in fuel relies on atomic absorption spectroscopy – ASTM D3831 – 12(2017). However, to bring the standards up to date with current additives used in the industry, ASTM is revising the test method D5059 (Standard test method for lead in gasoline by X-ray spectroscopy) to extend its scope and include the detection of manganese in gasoline (ASTM WK62596).
The LAB-X5000 XRF benchtop analyzer from Hitachi High-Tech can measure manganese in aviation fuel and motor gasoline. Its typical performance for this application is summarised in the table below:
| Analyte | Mn |
|---|---|
| Concentration Range | 0-300 |
| Unit | mg/1 |
| Standard Error of Calibration | 1.5 |
| Measurement Time | 60s |
| Limit of detection (3 sigma) | 0.8 |
| Limit of quantification (10 sigma) | 2.5 |
| Mid-range precision (2 sigma) | 2.1 |
The LAB-X is used in refineries worldwide to measure many elements found in fuels, including sulfur, from the ppm range to several percent. It conforms to ASTM D4294, ISO20847 and IP336. The LAB-X also meets the precision requirements of ASTM D5059.
Engineered for accurate and repeatable fuel oil analysis, the LAB-X5000 includes automatic compensation for changes in sample density due to variations in the oil matrix. This means you can measure different types of oils and fuels on one single calibration rather than matrix-match. This is especially useful if you are testing samples from different provenance.
The LAB-X range of analyzers has been trusted by the petroleum industry for decades. Over the years we have developed and improved the range to keep up with wider industry developments. Designed for round-the-clock use, the LAB-X5000 will help you ensure that you are meeting the right specification for manganese in your aviation fuel and gasoline.
If you would like to see the LAB-X5000 in action, get in touch with us to arrange a demo.
