- Nagham Salman Hassan AL- Maliky
Prof. Dr.Jabir Shanshool
Dr. Talib Kashmoula

 Reduced crude is considered usually as the main source for heating oils.Therefore, it was chosen in addition to, a commercial fuel oil in the present investigation, to improve their ability for pipelining.
 Blending with low viscous fractions or heating are the major commercial applications for pipeline transportation of residual fuel oils. Accurate data on oil viscosity as function of temperature and composition are required for design of oil pipelines. The effect of heating, up to 70oC on the lowering viscosity of reduced crude and fuel oil and their mixtures with gas oil were studied. The viscosity of the considered oils undergoes significant reduction by temperature increase. Percentage reductions are 53% and 50% can be achieved by heating of reduced crude and fuel oil respectively at 40oC. It is practically possible to improve the viscosity of residual oils using the method of blending with gas oil. As it is expected, light gas oil effected more viscosity reduction than heavy gas oil. The addition of methanol in low concentration to reduced crude and fuel oil leads to a reduction in their viscosities. The maximum decrease in viscosity (about 32% and 31% respectively) was obtained with addition of 3-4% by volume methanol.The effect of viscosity lowering by heating and diluting on pumping horse power requirement and flow rate was tested. The calculation was done using operating data of two locally available fuel oil pipelines of 250m and 10Km distances were supplied from Daura Refinery in Baghdad. The results indicated reasonable decrease in power requirements or increase in oil output by diluting with gas oil or temperature increase.  
 A model was modified to estimate the kinematic viscosity of blended residual fuel oil at different temperatures. The method is based up also on the concentration (wt. %) of the diluting component as follows: