Improvement the Physico-chemical Characteristics of Diesel Fuel using Gamma Irradiation

The effect of gamma irradiation on physico-chemical properties of petro-diesel fuel using different rate and absorbed doses has been studied. The diesel fuel samples were exposed to gamma radiation for 1.3 h using different absorbed doses: 3, 6, 10, and 15 kGy, with dose rates 2.27, 4.5, 7.4, and 11.15 kGy/h, respectively. Physico-chemical characteristics of diesel fuel were determined according to the standard test methods assigned by ASTM, characteristics are: cetane number, distillation recovery points, flash point, calorific value, density, and kinematic viscosity. The effect of gamma irradiation doses on organic compounds of diesel fuel was study using GC/MS technique. Experimental results show that the density, distillation, kinematic viscosity and flash point were decreased at absorbed doses 3, 6 and 15 kGy whereas increases at 10 kGy, corresponding with rate doses. Cetane number of diesel fuel increased after exposure to 3, 6, and 15 kGy but decreased at 10 kGy. These results can be attributed to the broken and formed bonds as a result of the high applied energy. The formed fragments at (10 kGy; 7.5 kGy/h) made a new compounds that have physical parameters affected negatively on the overall properties of diesel fuel. The formed fragments in diesel fuel after exposed to 3, 6, and 15 kGy (2.27, 4.5, and 11.15 kGy/h) have converted some of cyclic, aromatic, and branched organic compounds to linear hydrocarbons, which supported increasing of cetane number to 54. All characteristics have been improved within limits assigned by ASTM.