(104d) Selective Oxidation of Hydrotreated Diesel to Increase the Cetane Number

A new selective oxidation process was developed to improve the cetane number of the Hydrotreated diesel to ultra-low sulfur. The oxidation was carried out in a slurry type reactor using air and CuCr/I(4-PVP) catalyst to incorporate oxygen in the alkyl-naphtho-aromatics molecules. The Hydrotreated and the oxidized products were deeply characterized using three different solvents in a HPLC separation procedure, followed by GC-MS and HNMR analysis of the fractions. The light medium and heavy part of the Hydrotreated diesel were oxidized at different temperatures and space velocity at 10 bar of total pressure. The families of oxygenated naphthoaromatics were identified in the three fractions. In addition their acid number, fuel stability and cetane number were measured using ASTM methods. At low oxygen uptakes in the full range diesel the Cetane number increases proportional to the oxygen content. Then, at higher oxygen uptake, the rate of cetane number increase is largely reduced and the fuel stability deteriorated. The cetane number contribution of the light medium and heavy part of the diesel change differently as a function of oxygen content. The effect of temperature in the cetane number modification is discussed