Lubricity

The lubricity property in diesel shows the ability of diesel to minimize friction between surfaces in relative motion under load conditions. When lubricity is insufficient, many internal engine components including fuel pumps and injections are prone to excessive wear and metal damage. This results in a shortened service life and high replacement costs.

Naturally, diesel has a good lubricity property. However, the introduction of ultra-low sulfur diesel (ULSD) with a maximum sulfur limit of 10 mg/kg by a hydrodesulfurization process has resulted in a loss of diesel’s inherent lubricity.

While sulfur does not directly link to the lubricity property of diesel, the lower lubricity level of ULSD is an effect of the refinery process used for desulfurization. To increase lubricity values