سیدکامران ترکستانی

1 Analytical Chemistry Research Group، Research Institute of Petroleum Industry، P. O. Box: 14665-137، Fluorescent materials are some kind of reagents with vast applications in sensors. Considering the importance of the deremination of sulfate ion in environmental، chemical، pharaceuticals and food samples، in this research we used the fluorescence properties of 2،6-diphenyl-pyrylium tetrafluoroborate (DPF) for the design and construction of an optical sensor for the determination of SO42- ions. The results showed that the fluorescence intensity of DPF quenched upon the addition of sulfate ions، which was proportional to the sulfate concentration. Effective parameters were optimized and under optimal conditions the proposed optode was successfully applied to the determination of sulfate content in a drug sample. J. Color Sci. Tech. 7 (2013)، 47-52© Institute for Color Science and Technology.

In this study, Computational Fluid Dynamics analysis has been used for predicting Nusselt number, friction factor, and the overall enhancement efficiency in a double pipe heat exchanger under different Reynolds numbers and several of coiled wires geometries. A three-dimensional model has been used for investigation of the parameters in a simple tube and coiled wire inserted tubes. The results show that in the heat exchangers with coiled wires, the Nusselt number, and friction coefficient increases up to 2.2-3 times and 1.1-1.35 times respectively. By increasing the Reynolds number, the Nusselt number and the overall enhancement efficiency increase and the friction factor reduces. In addition, it was observed that by decreasing the wires curvature length, the friction coefficient and the Nusselt number increase. The average relative error between the CFD predictions and experimental data for simple tube is about 8% and for coiled wire geometry is about 8 to 18%. The CFD predictions have been compared to the experimental data and showed pretty good agreement, so the model presented in this study is suitable for predicting the Nusselt numbers and friction factor in the heat exchangers equipped with coiled wires.

In this paper, one of the most recent methods of desulfurization of fuel on which there has been a large number of researches since 2001, has been used. To achieve low sulfur levels in fuel, desulfurization of domestic and imported gasoline has been assessed by using several types of ionic liquids (green solvents). Additionally, by using experimental design and statistical software, the variables affecting the desulfurization efficiency have been determined and optimum conditions have been used for higher desulfurization efficiency. In this study, physical and chemical properties of gasoline especially the amount of sulfur content have been determined before and after each extraction. By evaluating the achieved results, it was found that ionic liquids or green solvents have a great impact on removing aromatic sulfur compounds. As a result, ionic liquid extraction can be used as a complementary method for HDS in deep desulfurization.