The impact of bioesters on lubricity of diesel fuels

The paper discusses the influence of two fatty acid methyl esters (bioesters) derived from soybean oil (SME) and from rapeseed oil (RME) on the lubricity of the petroleum diesel fuels: Ekodiesel (S:26 mg/kg, HFRR: 555 žm) and Citydiesel (S: 8 mg/kg, HFRR: 617 žm). High-frequency reciprocating rig (HFRR) equipment was used to examine diesel fuels, neat bioesters and blends containing from 0,1 % up to 20 % of soybean ester or rapeseed ester in each reference fuel. Lubricity evaluation was based on the measurement of the diameter of the wear scar left on the oscillated ball being in contact with a stationary disc submerged in the examined fuel. The examinations have shown that soybean ester is the most effective additive enhancing the lubricity of both base diesel fuels, but the changes in the lubricity were more dynamic for the diesel fuel with higher level of sulphur.