An Accurate Determination of the Cetane Number Value of GTL Diesel

A method for determining the exceptionally high cetane number value of SasolChevron GTL diesel is described. The conventional ASTM D613 method is inadequate at such high cetane number ratings where the reproducibility exceeds ± 8 numbers. The ignition delay of a selection of primary and secondary reference fuels were modeled and characterized using a combustion bomb apparatus and this information was used to calibrate a virtual cetane engine model. CFD simulations of the combustion bomb apparatus was used to validate the calculation process using n-heptane as the reference fuel. The analytical treatment was applied to Sasol GTL diesel and the cetane number was deduced as 86.9 with a 95% confidence interval of ±1.3.